BACKGROUND

The present disclosure relates to pumps, and in particular, to hydraulic piston pumps.

Industry experts agree that a reliable and efficient method of sludge, slurry, and paste transfer is accomplished with positive displacement, dual, reciprocating piston pumps, such as a poppet valve system.

The poppet valve system uses suction and discharge poppets to control the movement of material from the feed area into the delivery pipeline. This is accomplished with two piston pumps. While one piston pump is discharging material into the pipeline, the other piston pump is sucking material from the feed system. Then, the piston pumps switch roles. The piston pump that was discharging material sucks in material, and the piston pump that was filling up takes over the discharge task. This is an extremely reliable, efficient, and cost-effective way of conveying materials. A disadvantage of this positive displacement, dual, reciprocating piston pump system is that the material stops forward movement while the pistons change directions, and a pulsation can occur in the pipeline. While this does not affect the efficiency of the unit, it can cause noise and unwanted pipeline movement.

SUMMARY

A multi-piston pump includes a first pump having a first linear position sensor and a first pressure sensor, a second pump independent from the first pump, the second pump having a second linear position sensor and a second pressure sensor, a discharge pipe connected to the first pump and the second pump, a user interface, and a controller connected to the first pump, the second pump, and the user interface, the controller configured to coordinate operations of the first pump and the second pump based upon sensor inputs of position information and pressure information of the first pump and the second pump from the first linear position sensor, the first pressure sensor, the second linear position sensor, and the second pressure sensor to execute, in response to input received by the controller from the user interface, at least one diagnostic test from a group of diagnostic tests that includes a poppet seat leak pressure calibration test, a poppet seat leak test, a cylinder position test, a hydraulic pump leak down test, and a hydraulic piston seal test, and display a result of the diagnostic test on the user interface. A method for providing diagnostic testing of a multi-piston pump that includes a first pump having a first linear position sensor and a first pressure sensor, a second pump independent from the first pump, the second pump having a second linear position sensor and a second pressure sensor, a discharge pipe connected to the first pump and the second pump, a user interface, and a controller connected to the first pump, the second pump, and the user interface, the controller configured to coordinate operations of the first pump and the second pump based upon sensor inputs of position information and pressure information of the first pump and the second pump from the first linear position sensor, the first pressure sensor, the second linear position sensor, and the second pressure sensor includes executing, in response to input received by the controller from the user interface, at least one diagnostic test from a group of diagnostic tests that includes a poppet seat leak pressure calibration test, a poppet seat leak test, a cylinder position test, a hydraulic pump leak down test, and a hydraulic piston seal test and displaying a result of the diagnostic test on the user interface.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective side view of a multi-piston pump.

FIG. IB is a perspective end view of the multi-piston pump.

FIG. 2 is a schematic block diagram of the multi -piston pump.

FIGS. 3A, 3B, 3C, and 3D are a flowchart showing steps in a continuous flow process.

FIGS. 4A-4K illustrate eleven stages of one complete pumping cycle of the multi-piston pump.

FIGS. 5A-5C illustrate three stages in a start-up cycle of the multi-piston pump.

FIG. 6 is a partial schematic view of the multi-piston pump showing a hydraulic power unit status display of a hydraulic power unit.

FIG. 7 is a partial schematic view of the multi-piston pump showing a pump diagnostic display of the hydraulic power unit.

FIG. 8 is a flow chart showing steps in a poppet seat leak pressure calibration test.

FIG. 9 is a flow chart showing steps in a poppet seat leak test.

FIG. 10 is a flow chart showing steps in a cylinder position test.

FIG. 11 is a flow chart showing steps in a hydraulic pump leak down test.

FIG. 12 is a flow chart showing steps in a hydraulic piston seal test. DETAILED DESCRIPTION

A continuous flow multi-piston pump includes a pair of sequenced and reciprocating hydraulic pumps, driving material rams within material cylinders. The material cylinders intake and exhaust the desired pumping material that produces a continuous volumetric output, including during the changeover between the pumps. Each pump direction and speed is controlled using independent hydraulic direction, pressure and flow controls to maintain material cylinder output through a common pump discharge housing. Each material cylinder has an associated intake control valve (or suction poppet valve) and or associated exhaust control valve (or discharge poppet valve).

In one example, the operational sequence begins with each cylinder retracting to a known calibrated position or initial state. While retracting, the delivery cylinders intake material through open intake control valves, also known as suction poppet valves. The exhaust control valves, also known as discharge poppet valves, remain closed. The first and second delivery cylinders are performing an intake (or suction) stroke. When the delivery cylinder has reached the desired intake position, the intake stroke is complete, and the system waits for the other delivery cylinder to reach the desired intake position.

Once both cylinders have reached the desired intake position, the first delivery cylinder will extend at a desired speed and allowable pressure, known as the pressure stroke, to exhaust material out of the delivery cylinder and into the pump discharge housing. During a pressure stroke, the associated first suction poppet valve is closed and first discharge poppet valve is opened. During the first delivery cylinder pressure stroke, the pressure required to move the first ram is sampled.

While the first delivery cylinder is performing the pressure stroke, the second delivery cylinder applies hydraulic pressure to extend the second ram, at a static compression speed and at an allowable pressure that is about (just below) equal to the sampled pressure from first delivery piston. During the compression stroke, the suction poppet valve and the discharge poppet valve of the second delivery cylinder remain closed. This operation pressurizes the second delivery cylinder to a pressure that is approximately (just below) equal to the first delivery cylinder. Once that pressure is reached in the second delivery cylinder, the second delivery cylinder holds until the first delivery cylinder reaches the changeover position threshold.

When the first delivery cylinder reaches the changeover position threshold, both cylinders are in changeover, and executing the changeover between the first pump and the second pump simultaneously. During changeover, the discharge poppet valve opens for the second delivery cylinder that has completed a compression stroke and was holding, and the first and second delivery cylinders are now both open to the pump discharge housing. As such, the first pump and the second pump are both executing a discharge stroke during the changeover. The second delivery cylinder allowable pressure is raised to the operating system pressure. At an equal pump speed step and time interval step, the first ram speed ramps down and the second ram speed ramps up. As the rate of material flow decreases from the first delivery cylinder, the rate of material flow increases from the second delivery cylinder. When the speed change is complete for both the first material cylinder and the second material cylinder, or if the first material cylinder reaches an end of travel threshold, changeover is complete. The second material cylinder is now performing its pressure stroke at a desired pump speed and allowable pressure. During the second delivery cylinder pressure stroke, the pressure required to move the second ram is sampled.

When changeover is complete, the first delivery cylinder’ s hydraulic piston side is vented to a hydraulic tank which allows cylinder drift as the discharge poppet valve closes. The discharge poppet valve for the first delivery cylinder is closed. When the first discharge poppet valve for the first delivery cylinder is closed, the first suction poppet valve for the first delivery cylinder is opened. Hydraulic pressure is applied to the rod side of the first drive piston to retract the first delivery cylinder at a rate that is faster than the rate of the pressure stroke of the second delivery cylinder. The first delivery cylinder is now performing an intake, or suction, stroke. The suction stroke will continue until the calibrated retract position or initial state is achieved.

Once the first delivery cylinder suction stroke is complete, the first delivery cylinder suction poppet valve is closed. Hydraulic pressure is then applied to extend the ram of the first delivery cylinder, at a static compression speed, and at an allowable pressure that is about (just below) equal to the sampled pressure from the second delivery cylinder. During the compression stroke, the suction poppet valve and discharge poppet valve of the first delivery cylinder remain closed. This operation pressurizes the first delivery cylinder to a pressure that is approximately (j ust below) equal to the second delivery cylinder. Once that pressure is reached in the first delivery cylinder, the first delivery cylinder holds until the second delivery cylinder reaches the changeover position threshold.

When the second delivery cylinder reaches the changeover position threshold, both delivery cylinders are in changeover, executing the changeover between the first pump and the second pump simultaneously. During changeover, the discharge poppet valve opens for the first delivery cylinder that has completed a compression stroke and was holding, and the delivery cylinders are now both open to the pump discharge housing. As such, the first pump and the second pump are both executing a discharge stroke during the changeover. The first delivery cylinder allowable pressure is raised to the operating system pressure. At an equal pump speed step and time interval step, the second delivery cylinder speed ramps down and the first delivery cylinder speed ramps up. As the rate of material flow decreases from the second delivery cylinder, the rate of material flow increases from the first material cylinder. When the speed ramp is complete for both the first delivery cylinder and the second delivery cylinder, or if the second delivery cylinder reaches an end of travel threshold, the changeover is complete. The first delivery cylinder is now performing its pressure stroke at a desired pump speed and allowable pressure.

When the changeover is complete, the hydraulic piston side of the second delivery cylinder is vented to a hydraulic tank which allows cylinder drift as the discharge poppet valve closes. The discharge poppet valve for the second delivery cylinder is closed. When the second delivery cylinder discharge poppet valve is closed, the suction poppet valve for the second delivery cylinder is opened. Hydraulic pressure is applied to the rod side of the second drive piston to retract the second delivery cylinder. The second delivery cylinder is now performing a suction stroke. The suction stroke will continue until the calibrated retract position or initial state is achieved. From here the operational sequence for the continuous flow reciprocating twin multi-piston pump repeats.

Multi-Piston Pump - Figures 1A and IB

FIG. 1A is a perspective side view of multi-piston pump 10. FIG. IB is a perspective end view of multi-piston pump 10. FIG. 2 is a schematic block diagram of multi-piston pump 10. FIGS. 1A, IB, and 2 will be discussed together.

Multi-piston pump 10 includes first pump PMP1 and second pump PMP2 (shown in FIG. IB), frame 12, discharge pipe 14, poppet block 16, feeder 18, water box 20, hydraulic power unit (HPU) 22, drive cylinder (DRC) control modules 24, first linear position sensor LI, second linear position sensor L2, and accumulator circuit 25, which includes single accumulator bottle 26 and double accumulator bottle 28, controller 30, and user interface 31.

First pump PMP1 includes first drive cylinder DRCI (shown in FIGS. IB and 2), first delivery cylinder DC1 (shown in FIG. 2), first discharge poppet valve DPV1, first suction poppet valve SPV1, and first linear position sensor LI (shown in FIG. 2). Second pump PMP2 includes second drive cylinder DRC2, second delivery cylinder DC2, second discharge poppet valve DPV2, second suction poppet valve SPV2, and second linear position L2 (shown in FIG.2)

Frame 12 supports first drive cylinder DRCI, second drive cylinder DRC2, first delivery cylinder DC1 (shown in FIG. 2), and second delivery cylinder DC2. First drive cylinder DRCI is parallel to second drive cylinder DRC2. First delivery cylinder DC1 is parallel to second delivery cylinder DC2. First drive cylinder DRCI is connected to first delivery cylinder DC1 , and second drive cylinder DRC2 is connected to second delivery cylinder DC2. First drive cylinder DRCI and second drive cylinder DRC2 drive first delivery cylinder DC1 and second delivery cylinder DC2, respectively. First delivery cylinder DC1 is fluidly connected to first discharge poppet valve DPV1 and first suction poppet valve SPV1. Second delivery cylinder DC2 is fluidly connected to second discharge poppet valve DPV2 and second suction poppet valve SPV2.

First discharge poppet valve DPV1 and second discharge poppet valve DPV2 are in fluid communication with discharge pipe 14. First suction poppet valve SPV1 and second suction poppet valve SPV2 are fluidly connected to poppet block 16. Poppet block 16 controls first suction poppet valve SPV1, first discharge poppet valve DPV1, second suction poppet valve SPV2, and second discharge poppet valve DPV2. Feeder 18 is fluidly connected to first suction poppet valve SPV 1 and second suction poppet valve SPV2. Feeder 18 provides material to multi-piston pump 10. Water box 20 is positioned between first drive cylinder DRCI and first delivery cylinder DC1 and is also positioned between second drive cylinder DRC2 and second delivery cylinder DC2. Hydraulic power unit (HPU) 22 is supported by frame 12 and connected to first drive cylinder DRCI by piston line Pl and tank line T1 and connected to second drive cylinder DRC2 by piston line P2 and tank line T2. DRC control modules 24 are mounted on frame 12 and are connected to HPU 22. First linear position sensor LI senses the position of first drive piston DRP1 and is electrically connected to controller 30. First linear position sensor LI sends position information of first pump PMP1 to controller 30. Second linear position sensor L2 senses the position of second drive piston DRP2 and is electrically connected to controller 30. Second linear position sensor L2 sends position information of second pump PMP2 to controller 30. Accumulator circuit 25 is mounted on frame 12 and includes single accumulator bottle 26 and double accumulator bottle 28. Single accumulator bottle 26 is mounted on frame 12 and contains a bladder that stores hydraulic fluid. Double accumulator bottle 28 is mounted on frame 12 and comprises two bottles, each bottle containing a bladder that stores hydraulic fluid. Controller 30 is also electrically connected to user interface 31.

Schematic Block Diagram - Figure 2

First pump PMP1 includes first drive cylinder DRCI, first delivery cylinder DC1, first discharge poppet valve DPV1, first suction poppet valve SPV1, first linear position sensor LI, first drive piston DRP1, first ram Rl, first connecting rod CR1, first piston to tank orifice PTO1, first pressure sensor PS I, first temperature sensor TS1, first hydraulic speed/flow HS/F1 , first hydraulic pressure HP1 .

Poppet block 16 includes first suction poppet control solenoid SPCS1, first discharge poppet control solenoid DPCS1, first suction poppet rod fluid line SPRFL1, first suction poppet piston fluid line SPPFL1, first discharge poppet rod fluid line DPRFL1, and first discharge poppet piston fluid line DPPFL1.

DRC control modules 24 include first piston side tank PST1, first rod side tank RST1, first piston side pressure PSP1, first rod side pressure RSP1, first piston side tank fluid lines PSFL1, first rod side tank fluid lines RSFL1, first piston side pressure fluid lines PSFL1, and first rod side pressure fluid lines RSFL1.

Second pump PMP2 includes second drive cylinder DRC2, second delivery cylinder DC2, second discharge poppet valve DPV2, second suction poppet valve SPV2, second linear position sensor L2, second drive piston DRP2, second ram R2, second connecting rod CR2, second piston to tank orifice PTO2, second pressure sensor PS2, second temperature sensor TS2, second hydraulic speed/flow HS/F2, and second hydraulic pressure HP2.

Poppet block 16 also includes second suction poppet control solenoid SPCS2, second discharge poppet control solenoid DPCS2, second suction poppet rod fluid line SPRFL2, second suction poppet piston fluid line SPPFL2, second discharge poppet rod fluid line DPRFL2, and second discharge poppet piston fluid line DPPFL2.

DRC control modules 24 also include second piston side tank PST2, second rod side tank RST2, second piston side pressure PSP2, second rod side pressure RSP2, first piston side fluid line PSFL1, first rod side tank fluid line RSFL1, second piston side tank fluid line PSFL2, second rod side tank fluid line RSFL2, second piston side pressure fluid line PSFL2, and second rod side pressure fluid line RSFL2.

First drive piston DRP1 moves within first drive cylinder DRCI, and first ram Rl moves within first delivery cylinder DC1. First connecting rod CR1 extends from first drive piston DRP1 within first drive cylinder DRCI to first ram Rl within first delivery cylinder DC1, so that movement of first drive piston DRP1 produces corresponding movement of first ram R1 in first delivery cylinder DC1.

Second drive piston DRP2 moves within second drive cylinder DRC2, and second ram R2 moves within second delivery cylinder DC2. Second connecting rod CR2 extends from second drive piston DRP2 within second drive cylinder DRC2 to second ram R2 within second delivery cylinder DC2, so that movement of second drive piston DRP2 produces corresponding movement of second ram R2 in second delivery cylinder DC2.

First drive cylinder DRCI is connected to first delivery cylinder DC1 , and second drive cylinder DRC2 is connected to second delivery cylinder DC2. First delivery cylinder DC1 is fluidly connected to first discharge poppet valve DPV1 and first suction poppet valve SPV1 opposite from first drive cylinder DRCI. Second delivery cylinder DC2 is fluidly connected to second discharge poppet valve DPV2 and second suction poppet valve SPV2 opposite from second drive cylinder DRC2. First suction poppet valve SPV1, first discharge poppet valve DPV1, second suction poppet valve SPV2, and second discharge poppet valve DPV2 are fluidly connected to poppet block 16.

Each of first suction poppet valve SP V 1 , first discharge poppet valve DPV 1 , second suction poppet valve SPV2, and second discharge poppet valve DPV2 include a rod having a piston within a cylinder on one end and a trapezoidal valve stopper on the other end. Poppet block 16 controls first suction poppet valve SPV1, first discharge poppet valve DPV1, second suction poppet valve SPV2, and second discharge poppet valve DPV2.

Hydraulic power unit 22 is connected to first drive cylinder DRCI and second drive cylinder DRC2 via DRC control modules 24. First linear position sensor LI senses the position of the first drive piston DRP1 in first drive cylinder DRCI and provides a first piston position signal to controller 30. Similarly, second linear position sensor L2 senses the position of the second drive piston DRP2 in second drive cylinder DRC2 and provides a second piston position signal to controller 30. Accumulator circuit 25 supplies hydraulic fluid to poppet block 16.

Controller 30 is electrically connected to poppet block 16, DRC control modules 24, and hydraulic power unit 22. First piston to tank orifice PTO 1 and second piston to tank orifice PTO2 are fluidly connected to DRC control modules 24. First pressure sensor PSI and first temperature sensor TS1 sense pressure and temperature information of first pump PMP1 and provide pressure and temperature signals to controller 30 from first drive cylinder DRCI. Second pressure sensor PS2 and second temperature sensor TS2 sense pressure and temperature information of second pump PMP2 and provide pressure and temperature signals to controller 30 from second drive cylinder DRC2. First hydraulic pressure HP1 and second hydraulic pressure HP2 provide control signals to controller 30 from hydraulic power unit 22.

Poppet block 16 has first suction poppet control solenoid SPCS1, second suction poppet control solenoid SPCS2, first discharge poppet control solenoid DPCS1, second discharge poppet control solenoid DPCS2.

First suction poppet control solenoid SPCS1 is connected to first suction poppet valve SPV1 via first suction poppet rod fluid line SPRFL1 and first suction poppet piston fluid line SPPFL1. First suction poppet rod fluid line SPRFL1 is a fluid line connected to and between first suction poppet control solenoid SPCS1 and the rod side of first suction poppet valve SPV1. First suction poppet piston fluid line SPPFL1 is a fluid line connected to and between first suction poppet control solenoid SPCS1 and the piston side of first suction poppet valve SPV1.

Second suction poppet control solenoid SPCS2 is connected to second suction poppet valve SPV2 via second suction poppet rod fluid line SPRFL2 and second suction poppet piston fluid line SPPFL2. Second suction poppet rod fluid line SPRFL2 is a fluid line connected to and between second suction poppet control solenoid SPCS2 and the rod side of second suction poppet valve SPV2. Second suction poppet piston fluid line SPPFL2 is a fluid line connected to and between second suction poppet control solenoid SPCS2 and the piston side of second suction poppet valve SPV2.

First discharge poppet control solenoid DPCS1 is connected to first discharge poppet valve DPV1 via first discharge poppet rod fluid line DPRFL1 and first discharge poppet piston fluid line DPPFL1. First discharge poppet rod fluid line DPRFL1 is a fluid line connected to and between first discharge poppet control solenoid DPCS1 and the rod side of first discharge poppet valve DPV1. First discharge poppet piston fluid line DPPFL1 is a fluid line connected to and between first discharge poppet control solenoid DPCS 1 and the piston side of first discharge poppet valve DPV 1.

Second discharge poppet control solenoid DPCS2 is connected to second discharge poppet valve DPV2 via second discharge poppet rod fluid line DPRFL2 and second discharge poppet piston fluid line DPPFL2. Second discharge poppet rod fluid line DPRFL2 is a fluid line connected to and between second discharge poppet control solenoid DPCS2 and the rod side of second discharge poppet valve DPV2. Second discharge poppet piston fluid line DPPFL2 is a fluid line connected to and between second discharge poppet control solenoid DPCS2 and the piston side of second discharge poppet valve DPV2. DRC control modules 24 include first piston side tank PST1, first rod side tank RST1, first piston side pressure PSP1, first rod side pressure RSP1, second piston side tank PST2, second rod side tank RST2, second piston side pressure PSP2, second rod side pressure RSP2, all of which are modules fluidly connected to hydraulic power unit 22.

First piston side tank PST1, first rod side tank RST1, first piston side pressure PSP1, and first rod side pressure RSP1 are also fluidly connected to first drive cylinder DCR1. First piston side tank fluid line PSFL1 is a fluid line connected to and between first piston side tank PST1 and the piston side of first drive cylinder DRC1 . First rod side tank fluid line RSFL1 is a fluid line connected to and between first rod side tank RST1 and the rod side of first drive cylinder DRCI. First piston side pressure fluid line PSFL1 is a fluid line connected to and between first piston side pressure PSP1 and the piston side of first drive cylinder DRCI. First rod side pressure fluid line RSFL1 is a fluid line connected to and between first rod side pressure RSP1 and the rod side of first drive cylinder DRCI. First piston to tank orifice PT01 is fluidly connected to first piston side pressure PSP 1. First linear position sensor LI determines the position of first drive cylinder DRCI and first delivery cylinder DC1.

Second piston side tank PST2, second rod side tank RST2, second piston side pressure PSP2, and second rod side pressure RSP2 are fluidly connected to second drive cylinder DCR2. Second piston side tank fluid line PSFL2 is a fluid line connected to and between second piston side tank PST2 and the piston side of second drive cylinder DRC2. Second rod side tank fluid line RSFL2 is a fluid line connected to and between second rod side tank RST2 and the rod side of second drive cylinder DRC2. Second piston side pressure fluid line PSFL2 is a fluid line connected to and between second piston side pressure PSP2 and the piston side of second drive cylinder DRC 1. Second rod side pressure fluid line RSFL2 is a fluid line connected to and between second rod side pressure RSP2 and the rod side of second drive cylinder DRC2. Second piston to tank orifice PT02 is fluidly connected to second piston side pressure PSP2. Second linear position sensor L2 determines the position of second drive cylinder DRC2 and second delivery cylinder DC2.

First drive cylinder DRCI drives first delivery cylinder DC1. Second drive cylinder DRC2 drives second delivery cylinder DC2. First discharge poppet valve DPV1 opens and closes to discharge material from first delivery cylinder DRCI. First suction poppet valve SPV1 opens and closes to input material to first delivery cylinder DC1. Second discharge poppet valve DPV2 opens and closes to discharge material from second delivery cylinder DC2. Second suction poppet valve SPV2 opens and closes to input material to second delivery cylinder DC2.

First discharge poppet valve DPV1 and second discharge poppet valve DPV2 are in fluid communication with discharge pipe 14 such that material is discharged from first delivery cylinder DC1 and second delivery cylinder DC2 through discharge pipe 14.

Poppet block 16 hydraulically controls first suction poppet valve SPV1, first discharge poppet valve DPV1 , second suction poppet valve SPV2, and second discharge poppet valve DPV2 using hydraulic fluid from accumulator circuit 25. Accumulator circuit 25 supplies hydraulic fluid to extend or retract first discharge poppet valve DPV 1 , first suction poppet valve SPV1, second discharge poppet valve DPV2, and second suction poppet valve SPV2 based on signals from first suction poppet control solenoid SPCS1, second suction poppet control solenoid SPCS2, first discharge poppet control solenoid DPCS1, and second discharge poppet control solenoid DPCS2 of poppet block 16.

Hydraulic power unit (HPU) 22 is controlled by controller 30 based upon inputs from user interface 31 and sensor inputs from linear position sensors LI and L2, pressure sensors PSI and PS2, and temperature sensors TS1 and TS2. HPU 22 controls flow of hydraulic control fluid through DRC control modules 24 to control the direction and speed of movement of drive pistons DRP1 and DRP2 and rams R1 and R2. In addition, controller 30 controls operation of poppet suction valves SPV1 and SPV2, and discharge valves DPV1 and DPV2 through poppet block 16.

First suction poppet valve SPV1 and first discharge poppet valve DPV1 open and close based on input from first suction poppet control solenoid SPCS 1 and first discharge poppet control solenoid DPCS1. When first suction poppet control solenoid SPCS1 is activated by controller 30, hydraulic fluid from accumulator circuit 25 is delivered to first suction poppet valve SPV 1. When first discharge poppet control solenoid DPCS1 is activated by controller 30, hydraulic fluid from accumulator circuit 25 is delivered to first discharge poppet valve DPV1. When first suction poppet control solenoid SPCS 1 is not activated, hydraulic fluid from accumulator circuit 25 is not delivered to first suction poppet valve SPV1. When first discharge poppet control solenoid DPCS1 is not activated, hydraulic fluid from accumulator circuit 25 is not delivered to first discharge poppet valve DPV 1.

Second suction poppet valve SPV2 and second discharge poppet valve DPV2 open and close based on input from second suction poppet control solenoid SPCS2 and second discharge poppet control solenoid DPCS2. When second suction poppet control solenoid SPCS2 is activated by controller 30, hydraulic fluid from accumulator circuit 25 is delivered to second suction poppet valve SPV2. When second discharge poppet control solenoid DPCS2 is activated by controller 30, hydraulic fluid from accumulator circuit 25 is delivered to second discharge poppet valve DPV2. When second suction poppet control solenoid SPCS2 is not activated, hydraulic fluid from accumulator circuit 25 is not delivered to second suction poppet valve SPV2. When second discharge poppet control solenoid DPCS2 is not activated, hydraulic fluid from accumulator circuit 25 is not delivered to second discharge poppet valve DPV2.

First piston side tank PST1 and first rod side pressure RSP1 are activated or inactivated by controller 30 at the same time, while first rod side tank RST1 and first piston side pressure PSP1 are activated or inactivated by controller 30 at the same time and opposite from first piston side tank PST1 and first rod side pressure RSP1. Second piston side tank PST2 and second rod side pressure RSP2 are activated or inactivated by controller 30 at the same time, while second rod side tank RST2 and second piston side pressure PSP2 are activated or inactivated by controller 30 at the same time and opposite from second piston side tank PST2 and second rod side pressure RSP2. Controller 30 coordinates activation of poppet block 16 with hydraulic power unit 22 and DRC control modules 24 such that first delivery cylinder DC1 and second delivery cylinder DC2 move in conjunction with first suction poppet valve SPV1, first discharge poppet valve DPV1, second suction poppet valve SPV2, and second discharge poppet valve DPV2 to result in suction or discharge by first delivery cylinder DC1 and second delivery cylinder DC2, respectively, to result in continuous flow through discharge pipe 14.

For example, controller 30 may send signals to HPU 22 and accumulator circuit 25 for second delivery cylinder DC2 to execute a suction stroke based on linear position information from first linear position sensor LI and second linear position sensor L2. HPU 22 activates second rod side pressure RSP2 and second piston side tank PST2 via hydraulic control fluid. As such, HPU 22 also uses hydraulic control fluid to activate first piston side pressure PSP 1 and first rod side tank RST 1. Second drive piston DRP2 in drive cylinder DRC2 moves in response to the hydraulic fluid and delivery cylinder DC2 executes a suction stroke. At the same time, controller signals to poppet block 16 to activate second suction poppet control solenoid SPCS2 so that hydraulic fluid from accumulator circuit 25 moves to second suction poppet valve SPV2. As a result, hydraulic fluid moves into the rod side of the cylinder of second suction poppet valve SPV2, causing the rod to move such that the valve stopper moves. Second suction poppet valve opens and material enters second delivery cylinder DC2.

First delivery cylinder DC1 and second delivery cylinder DC2 operate independently from each other so that the flow from discharge pipe 14 is continuous and near constant. As a result, there is no pulsation in the flow from discharge pipe 14.

Flowchart - Figures 3A-3D

FIGS. 3A, 3B, 3C, and 3D are a flowchart of continuous flow process 32 showing steps 34-76. Continuous flow process 32 begins with initiation of startup operation at step 34 in FIG. 3 A.

At step 34, continuous flow system values are initialized by controller 30. Step 34 is the first step in the start-up cycle of multi-piston pump 10, which initiates the continuous flow pump logic at controller 30.

At step 36, first suction poppet control solenoid SPCS1 and second suction poppet control solenoid SPCS2 are turned on by controller 30. First suction poppet control solenoid SPCS1 and second suction poppet control solenoid SPCS2 are activated simultaneously during the start-up cycle of multi-piston pump 10 to deliver hydraulic fluid and cause first suction poppet valve SPV1 and second suction poppet valve SPV2 to retract and open.

At step 38, first delivery cylinder DC1 and second delivery cylinder DC2 are both executing a suction stroke, as seen in FIG. 5 A. First drive cylinder DRCI and second drive cylinder DRC2 are both at a starting position for a suction stroke, where the hydraulic fluid is in the piston side of both cylinders to push each of first drive piston DRP1 and second drive piston DRP2 to an extended position, or the furthest forward position toward first delivery cylinder DC1 and second delivery cylinder DC2. As a result, first ram R1 of first delivery cylinder DC1 and second ram R2 of second delivery cylinder DC2 are in an extended position, which is the furthest forward position toward first suction poppet valve SPV1 and second suction poppet valve SPV2. First delivery cylinder DC1 and second delivery cylinder DC2 are retracted by controller 30. The hydraulic fluid of first drive cylinder DRC 1 and second drive cylinder DRC2 is directed to the rod side of both cylinders to push each of first drive piston DRP1 and second drive piston DRP2 rearward to a retracted start position, or the furthest back position toward first linear position sensor LI and second linear position sensor L2. As a result, first ram R1 of first delivery cylinder DC1 and second ram R2 second delivery cylinder DC2 are also retracted to an initial calibrated state, which is the rearward back position toward first drive cylinder DRCI and second drive cylinder DRC2. As first ram R1 of first delivery cylinder DC1 and second ram R2 of second delivery cylinder DC2 retract to starting positions, first delivery cylinder DC1 undergoes initial filling of material through first suction poppet valve SPV1, and second delivery cylinder DC2 undergoes initial filling of material through second suction poppet valve SPV2. At this point, both first delivery cylinder DC1 and second delivery cylinder DC2 are fully filled with material to be pumped, as shown in FIG. 5B.

At step 40, controller 30 determines whether first ram R1 of first delivery cylinder DC1 and second ram R2 of second delivery cylinder DC2 are fully retracted based on position information from first linear position sensor LI and second linear position sensor L2. If so, continuous flow process 32 proceeds to step 42. If not, continuous flow process proceeds back to step 38.

At step 42, first suction poppet valve SPV 1 and second suction poppet valve SPV2 turn off, and first delivery cylinder DC1 executes a pressure stroke, as seen in FIG. 4A. First suction poppet control solenoid SPCS1 and second suction poppet control solenoid SPCS2 are activated to direct oil to the piston side of first suction poppet valve SPV1 and second suction poppet valve SPV2 via first suction poppet piston fluid line SPPFL1 and second suction poppet piston fluid line SPPFL2, respectively. First suction poppet valve SPV1 and second suction poppet valve SPV2 extend to a closed position. First discharge poppet control solenoid DPCS 1 is activated and hydraulic fluid is delivered through first discharge poppet rod fluid line DPRFL1 to the rod side of first discharge poppet valve DPV1. As a result of the force produced by the pressure of the material in first delivery cylinder DC1, first discharge poppet valve DPV1 is forced open and is retracted from first delivery cylinder DC1, opening first discharge poppet valve DPV1. First piston side pressure PSP1 in DRC control module 24 is activated by controller 38 using hydraulic fluid from hydraulic power unit 22 to deliver hydraulic fluid to the piston side of first drive cylinder DRCI. As such, first rod side tank RST1 of DRC control module 24 is controlled by controller 30 to vent control fluid through first rod side tank fluid line RSFL1 from the rod side of first drive cylinder DRCI. The first drive piston DRP1 of first drive cylinder DRCI extends, causing the piston of first delivery cylinder DC1 to also extend, executing a pressure stroke. As a result, material from first delivery cylinder DC1 is pushed through first discharge poppet valve DPV1 to discharge pipe 14. At this point, initialization has been completed. In alternate embodiments, multi-piston pump 10 may undergo any suitable initialization or initiate any suitable startup operation. For example, first delivery cylinder DC1 and second delivery cylinder DC2 of multi -piston pump 10 may not both retract to execute suction strokes at start-up. Multi-piston pump 10 may engage only one of first delivery cylinder DC1 or second delivery cylinder DC2 at start-up.

Step 44 is the first recursive state, which is the first step, or stage, in a normal repetitive cycle of multi-piston pump 10 in which pumps Pl and P2 alternate in performing (a) delivery of material from one delivery cylinder to discharge pipe 14 and (b) filling and compression of material in the other delivery cylinder. At step 44, second delivery cylinder DC2 executes a compression stroke, as shown in FIG. 4B. Second piston side pressure PSP2 is in DRC control module 24 is activated by controller 30 to deliver hydraulic fluid from hydraulic power unit 22 through second piston side pressure fluid line PSFL2 to the piston side of second drive cylinder DRC2. Controller 30 regulates the pressure from hydraulic power unit 22 at a pressure equal to PSP1, pushing the second ram R2 of second delivery cylinder DC2 forward to execute a compression stroke. Second rod side tank RST2 in DRC control module 24 is activated by controller 30 to remove hydraulic fluid through second rod side tank fluid line RSFL2 from the rod side of second drive cylinder DRC2. Second suction poppet valve SPV2 and second discharge poppet valve DPV2 are closed, the pressure of second delivery cylinder DC2 increases until pressure sensor PS2 signals controller 30 that the pressure is just below the opening pressure of second discharge poppet valve DPV2. At that point, the compression stroke is complete. The pressure in second delivery cylinder DC2 is just below the pressure in first delivery cylinder DC1. Second delivery cylinder DC2 holds until first delivery cylinder DC1 is ready for changeover. First delivery cylinder DC1 continues to execute the discharge stroke.

At step 46, controller 30 initiates the changeover from first delivery cylinder DC1 to second delivery cylinder DC2 when first piston DRP1 and first ram R1 have reached the changeover point of their forward stroke, as indicated by first linear position sensor LI to controller 30. First delivery cylinder DC1 and second delivery cylinder DC2 undergo changeover simultaneously. As shown in FIG. 3A and FIG. 4C, when changeover occurs, second delivery cylinder DC2 is ready to begin a pressure stroke, and first delivery cylinder DC1 is ready to transition from a pressure stroke to a suction stroke, first ram R1 beginning to reach full extension. As such, at step 46, controller 30 determines whether first ram R1 is at the changeover position based on position information from first linear position sensor LI. If the piston of first delivery cylinder DC1 has not reached the changeover position, continuous flow process 32 repeats step 44 and 46.

At step 48, and as shown in FIG. 3B and FIG. 4C, the pressure of second delivery cylinder DC2 is raised to full system pressure. Second ram R2 of second delivery cylinder DC2 ramps up speed, increasing the pressure in second delivery cylinder DC2 to full system pressure. Second discharge poppet control solenoid DPCS2 is activated to deliver hydraulic fluid via second discharge poppet rod fluid line DPRFL2 to the rod side of the material cylinder of second discharge poppet valve DPV2, which retracts and opens. Second delivery cylinder DC2 executes a discharge stroke. First delivery cylinder DC1 has reached changeover position and continues to execute a discharge stroke, ramping down speed. As such, at changeover, first delivery cylinder DC1 and second delivery cylinder DC2 are executing a discharge stroke. First ram R1 of first delivery cylinder DC1 ramps down speed until reaching a fully extended position and coming to a stop. The changeover between first delivery cylinder DC1 and second delivery cylinder DC1 is occurring.

At step 50, controller 30 a determines whether first ram R1 of first delivery cylinder DC1 is fully extended. If the speed ramp down is complete such that first ram R1 has come to a stop, the discharge stroke within first delivery cylinder DC 1 is complete and continuous flow process 32 proceeds to step 52. If first ram R1 of first delivery cylinder DC1 is not fully extended, continuous flow process 32 repeats step 48.

At step 52, first piston to tank orifice PTO1 of first drive cylinder DRCI turns on. First piston side pressure PSP1 turns off and hydraulic control fluid is no longer being delivered to the piston side of first drive cylinder DRCI. The first discharge poppet valve DPV 1 closes in response to first discharge poppet control solenoid DPCS 1 activating to deliver hydraulic fluid through first discharge poppet fluid line DPPFL1 to the piston side of first discharge poppet valve DPV1. The first ram R1 of first delivery cylinder DC1 cannot extend further. Any excess hydraulic pressure fluid acting on DRP1 is routed to first piston to tank orifice PTO1. The pressure in first delivery cylinder DC1 decreases. Continuous flow process 32 proceeds to step 54.

At step 54, controller 30 determines whether first discharge poppet valve DPV1 of first delivery cylinder DC1 is fully closed. If first discharge poppet valve DPV1 is fully closed, the changeover is complete and continuous flow process 32 progresses to step 56. If first discharge poppet valve DPV1 is not fully closed, continuous flow process 32 repeats step 52.

At step 56, first piston to tank orifice PTO1 of first drive cylinder DRCI is turned off by controller. Controller 30 activates first suction poppet control solenoid SPCS1 to deliver hydraulic fluid through first suction poppet rod fluid line SPRFL1 to the rod side of first suction poppet valve SPV1, which causes first suction poppet valve SPV1 to open. First ram R1 of first delivery cylinder DC1 executes a suction stroke, as seen in FIG. 4E. First rod side pressure RSP1 delivers hydraulic control fluid via first rod side pressure fluid line RSPFL1 to the rod side of first drive cylinder DRCI. First piston side tank PST1 is also activated such that first drive piston DRP1 of first drive cylinder DRCI retracts, causing first ram R1 of first delivery cylinder DC1 to retract at a rate of rearward movement that is greater than the rate of forward movement of second ram R2. As first ram R1 retracts, first delivery cylinder DC1 undergoes filling of material as material is pulled through first suction poppet valve SPV1. As a result, first delivery cylinder DCl will complete filling before second delivery cylinder DC2 has completed the pressure stroke. This allows time for a compression stroke to be performed so that first delivery cylinder DCl is pressurized to just below the opening pressure of first discharge poppet valve DPV1. First discharge poppet valve DPV 1 remains closed. Second delivery cylinder DC2 continues to execute the discharge stroke.

At step 58, controller 30 determines whether first ram R1 of first delivery cylinder DCl is fully retracted based upon a signal from first linear position sensor LI. If first ram R1 of first delivery cylinder DCl is fully retracted, the suction stroke is complete. First suction poppet control solenoid SPCS 1 is activated to direct hydraulic fluid via first suction poppet piston fluid line SPPFL1 to the piston side of first suction poppet valve SPV1, extending first suction poppet valve SPV 1 such that first suction poppet valve SPV1 is closed, or off. First discharge poppet valve DPV 1 remains closed. First piston side tank PST1 and first rod side pressure RSP1 are off. Second delivery cylinder DC2 continues to execute the discharge stroke. If first ram R1 of first delivery cylinder DCl has not fully retracted, continuous flow process 32 repeats step 56.

At step 60, first delivery cylinder DCl executes a compression stroke, as shown in FIGS. 4F and 4G. First piston side pressure PSP1 is in DRC control module 24 is activated by controller 30 to deliver hydraulic fluid from hydraulic power unit 22 through first piston side pressure fluid line PSFL1 to the piston side of first drive cylinder DRC. Controller 30 regulates the pressure from hydraulic power unit 22 at a pressure equal to PSP2, pushing the first ram R1 of first delivery cylinder DCl forward to execute a compression stroke. First rod side tank RST 1 in DRC control module 24 is activated by controller 30 to remove hydraulic control fluid through first rod side tank fluid line RSFL1 from the rod side of first drive cylinder DRCI. First discharge poppet valve DPV1 and first suction poppet valve SPV1 are closed. The pressure of first delivery cylinder DCl increases until first pressure sensor PS 1 signals controller 30 that the pressure is just below the opening pressure of the pressure of first discharge poppet valve DPV 1. At that point, the compression stroke is complete. The pressure in first delivery cylinder DC1 is just below the pressure in second delivery cylinder DC2. First delivery cylinder DC1 holds until second delivery cylinder DC2 is ready for changeover. Second delivery cylinder DC2 continues to execute the discharge stroke.

At step 62, controller 30 is ready to initiate the changeover from second delivery cylinder DC2 to first delivery cylinder DC1, as shown in FIG. 4H. First delivery cylinder DC I is holding ready to begin a pressure stroke while second delivery cylinder DC2 is ready to transition from a pressure stroke to a suction stroke when second ram R2 has reached the changeover point of the forward stroke. As such, controller 30 determines whether second ram R2 of second delivery cylinder DC2 is at the changeover position based on position information from second linear position sensor L2. If second ram R2 of second delivery cylinder DC2 has not reached the changeover position, continuous flow process 32 repeats steps 60 and 62. If second ram R2 of second delivery cylinder DC2 has reached the changeover position, continuous flow process 32 proceeds to step 64.

At step 64, and as shown in FIG. 3C and FIG. 4H and 41, first delivery cylinder DC1 and second delivery cylinder DC2 undergo changeover simultaneously. The pressure of first delivery cylinder DC1 is raised to full system pressure. First ram R1 of first delivery cylinder DC1 ramps up speed, increasing pressure in first delivery cylinder DC1 to full system pressure. First discharge poppet control solenoid DPCS1 is activated to deliver hydraulic fluid via first discharge poppet rod fluid line DPRFL1 to the rod side of the material cylinder of first discharge poppet valve DPV1, which retracts and opens. First delivery cylinder DC1 executes a discharge stroke. Second delivery cylinder DC2 continues to execute a discharge stroke, ramping down speed. As such, at changeover, first delivery cylinder DC1 and second delivery cylinder DC2 are executing a discharge stroke. Second ram R2 of second delivery cylinder DC2 ramps down speed until reaching a fully extended position and coming to a stop. The changeover between second delivery cylinder DC2 and first delivery cylinder DC1 is occurring.

At step 66, controller 30 determines whether second ram R2 of second delivery cylinder DC2 is fully extended. If the speed ramp down is complete such that second ram R2 has come to a stop, the discharge stroke within second delivery cylinder DC2 is complete and continuous flow process 32 proceeds to step 68. If second ram R2 of second delivery cylinder DC2 is not fully extended, continuous flow process 32 repeats step 64. At step 68, second piston to tank orifice PT02 of second drive cylinder DRC2 turns on. Second piston side pressure PSP2 turns off and hydraulic control fluid is no longer being delivered to the piston side of second drive cylinder DRC2. The second discharge poppet valve DPV2 closes in response to second discharge poppet control solenoid DPCS2 activating to deliver hydraulic fluid through second discharge poppet fluid line DPPFL2 to the piston side of second discharge poppet valve DPV2. The second ram R2 of second delivery cylinder DC2 cannot extend further. Any excess hydraulic pressure fluid acting on DRP2 is routed to second piston to tank orifice PT02. The pressure in second deliver}' cylinder DC2 decreases. Continuous flow process 32 proceeds to step 70.

At step 70, controller 30 determines whether second discharge poppet valve DPV2 of second delivery cylinder DC2 is fully closed. If second discharge poppet valve DPV2 is fully closed, the changeover is complete and continuous flow process 32 progresses to step 72. If second discharge poppet valve DPV2 is not fully closed, continuous flow process 32 repeats step 68.

At step 72, second piston to tank orifice PTO2 of second drive cylinder DRC2 is turned off by controller 30. Controller 30 activates second suction poppet control solenoid SPCS2 to deliver hydraulic fluid via second suction popped rod fluid line SPRFL2 to the rod side second suction poppet valve SPV2, which causes second suction poppet valve SPV2 to open. Second ram R2 of second delivery cylinder DC2 executes a suction stroke, as seen in FIG. 4J. Second rod side pressure RSP2 delivers hydraulic control fluid via second rod side pressure fluid line RSPFL2 to the rod side of second drive cylinder DRC2. Second piston side tank PST2 is also activated such that second drive piston DRP2 of second drive cylinder DRC2 retracts, causing second ram R2 of second delivery cylinder DC2 to retract at a rate of rearward movement that is greater than the rate of forward movement of first ram Rl. As second ram R2 retracts, second delivery cylinder DC2 undergoes filling of material as material is pulled through second suction poppet valve SPV2. As a result, second delivery cylinder DC2 will complete filling before first delivery cylinder DC1 has completed the pressure stroke. This allows time for a compression stroke to be performed so that second delivery cylinder DC2 is pressurized to just below the opening pressure of second discharge poppet valve DPV2. Second discharge poppet valve DPV2 remains closed. First delivery cylinder DC1 continues to execute the discharge stroke.

At step 74, controller 30 determines whether second ram R2 of second delivery cylinder DC2 is fully retracted based upon a signal from second linear position sensor L2. If second ram R2 of second delivery cylinder DC2 is fully retracted, the suction stroke is complete. Continuous flow process 32 proceeds to step 76. If second ram R2 of second delivery cylinder DC2 has not fully retracted, continuous flow process 32 repeats step 72.

At step 76, second piston side tank PST2 and second rod side pressure RSP2 turn off. Second suction poppet control solenoid SPCS2 is activated by controller 30 to direct hydraulic fluid via second suction poppet piston fluid line SPPFL2 to the piston side of second suction poppet valve SPV2, extending second suction poppet valve SPV2 such that second suction poppet valve SPV2 is closed, or off, as shown in FIG. 4K. Second discharge poppet valve DVP1 remains closed. First delivery cylinder DC1 continues to execute the discharge stroke. Following step 76, continuous flow pump logic 32 returns to step 44 and repeats steps 44-76.

Separating the operation of first delivery cylinder DC1 and second delivery cylinder DC2 allows for individual control of first delivery cylinder DC1 and section delivery cylinder DC2. Each of first delivery cylinder DC1 and second delivery cylinder DC2 completes a suction stroke and completes a compression stroke and holds before the other delivery cylinder ends a pressure (discharge) stroke. As a result, the suction strokes take place more quickly than the pressure strokes. Each of first delivery cylinder DC1 and second delivery cylinder DC2 also engages in a compression stroke so that the pressure within the delivery cylinder is near the pressure required to open the corresponding discharge poppet valve DPV1 or DPV2 for the pressure stroke before the other delivery cylinder completes its pressure stroke. The quick retraction and compression stroke to increase the cylinder pressure of the filled delivery cylinder to that just below the pressure in the other cylinder, and the pressure needed to force the discharge poppet valve open, added digital feedback, such as location knowledge from first linear position sensor LI and second linear position sensor L2, and the ability to vary the pressure to each of first delivery cylinder DC1 and second delivery cylinder DC2 has produced a nearly seamless transition from first delivery cylinder DC1 to second delivery cylinder DC2. As a result, there is a negligible drop in pressure during the changeovers between first delivery cylinder DC1 and second delivery cylinder DC2, and the pipeline pulsation is reduced to a nearly undetectable operation.

Full Cycle Piston Positions - Figures 4A-4K

FIGS. 4A-4K illustrate the positions of delivery pistons DLP1 and DLP2, suction poppet valves SPV1 and SPV2, and discharge poppet valves DPV1 and DPV2 during a complete cycle of pump 10. FIG. 4A is a schematic view of first stage 80 in cycle 82 of piston pump 10. FIG. 4B is a schematic view of second stage 84 in cycle 82 of piston pump 10. FIG. 4C is a schematic view of third stage 86 in cycle 82 of piston pump 10. FIG. 4D is a schematic view of fourth stage 88 in cycle 82 of piston pump 10. FIG. 4E is a schematic view of fifth stage 90 in cycle 82 of piston pump 10. FIG. 4F is a schematic view of sixth stage 92 in cycle 82 of piston pump 10. FIG. 4G is a schematic view of seventh stage 94 in cycle 82 of piston pump 10. FIG. 4H is a schematic view of eighth stage 96 in cycle 82 of piston pump 10. FIG. 41 is a schematic view of ninth stage 98 in cycle 82 of piston pump 10. FIG. 4J is a schematic view of tenth stage 100 in cycle 82 of piston pump 10. FIG. 4K is a schematic view of eleventh stage 102 in cycle 82 of piston pump 10.

Multi-piston pump 10 includes first delivery cylinder DC1, second delivery cylinder DC2, first discharge poppet valve DPV1, first suction poppet valve SPV1, second discharge poppet valve DPV2, and second suction poppet valve SPV2.

As seen in FIG. 4A, at first stage 80 in cycle 82, first delivery cylinder DC1 begins a pressure stroke in response to controller 30 signaling to HPU 22 after receiving position information regarding first delivery cylinder DC1 from first linear position sensor LI. Second delivery cylinder DC2 is in a retracted state, having just completed a suction stroke. Second linear position sensor L2 sends a signal to controller 30 that the suction stroke is complete based on the position of second drive piston DRP2, and thus second ram R2. First discharge poppet valve DPV1 opens and first suction poppet valve SPV1 closes. Controller 30 has signaled to poppet block 16 to deliver hydraulic fluid to the piston side of first suction poppet valve SPV1 and hydraulic fluid to the rod side of first discharge poppet valve DPV1. Second discharge poppet valve DPV2 closes and second suction poppet valve SPV2 remains closed.

As seen in FIG. 4B, second stage 84 in cycle 82 includes first delivery cylinder DC1 continuing the pressure stroke. The piston of first delivery cylinder DC1 continues to extend. First suction poppet valve SPV 1 remains closed and first discharge poppet valve DPV1 remains open, material discharging through first discharge poppet valve DPV1. When controller 30 receives information from second linear position sensor L2 indicating that second ram R2 has completed the suction stroke, second delivery cylinder DC2 executes a compression stroke. Second discharge poppet valve DPV2 and section suction poppet valve SPV2 are closed. Controller 30 directs hydraulic fluid through HPU 22 such that second ram R2 of second delivery cylinder DC2 beings to extend, increasing the pressure in second delivery cylinder DC2. As a result, the pressure in second delivery cylinder DC2 increases to a pressure just below the pressure in first delivery cylinder DC1, or just below the pressure required to open second discharge poppet valve DPV2 and execute a discharge stroke. Second delivery cylinder DC2 holds until first delivery cylinder DC1 is ready for changeover.

As seen in FIG. 4C, at third stage 86 in cycle 82, first delivery cylinder DC1 continues the pressure stroke at a changeover position, ready for changeover from first delivery cylinder DC1 to second delivery cylinder DC2. Changeover is initiated by controller 30 when pressure information from first pressure sensor PS 1 and second pressure sensor PS2 indicates that the pressures in first delivery cylinder DC1 and second delivery cylinder DC2 are almost equal, and first linear position sensor LI signals to controller 30 that first drive piston DRP1 is nearing completion of the discharge stroke, or at the changeover position. First delivery cylinder DC1 and second delivery cylinder DC2 undergo changeover simultaneously. Controller 30 sends signals to poppet block 16 and HPU 22. First suction poppet valve SPV1 remains closed and first discharge poppet valve DPV1 remains open. Second delivery cylinder DC2 begins to execute a pressure stroke at the changeover. The second discharge poppet valve DPV2 opens and the second suction poppet valve SPV2 remains closed in response to hydraulic fluid from poppet block 16, coordinated by controller 30. The pressure in second delivery cylinder DC2 has reached full system pressure, the pressure in second delivery cylinder DC2 being sufficient to open second discharge poppet valve DPV2 and begin the discharge stroke. The pressure in second delivery cylinder DC2 is equal to the pressure in first delivery cylinder DC1. Material is discharged from first delivery cylinder DC1 and second delivery cylinder DC2 during the changeover from first pump PMP1 to second pump PMP2. During changeover, both first delivery cylinder DC1 and second delivery cylinder DC2 are executing a discharge stroke, and there is no pressure disruption.

As seen in FIG. 4D, at fourth stage 88 in cycle 82, first delivery cylinder DC1 ends the pressure stroke. First ram R1 reaches full extension and stops, depressurizing first delivery cylinder DC1. Position information for first delivery cylinder DC1 is gathered from first drive cylinder DRCI by first linear position sensor LI and sent to controller 30, and pressure information for first delivery cylinder DC1 is gathered from first drive cylinder DRCI by first pressure sensor PSI and sent to controller 30. Controller 30 signals first discharge poppet DPV 1 to close and first suction poppet valve SPV 1 to remain closed. Second delivery cylinder DC2 continues to execute the pressure stroke in response to signals sent by controller 30 to HPU 22 based on the position and pressure in second delivery cylinder DC2, gathered from second drive cylinder DRC2 by second linear position sensor L2 and second pressure sensor PS2 and sent to controller 30. Material is discharged from second delivery cylinder DC2 through second discharge poppet valve DPV2. The changeover from first delivery cylinder DC1 to second delivery cylinder DC2 is complete.

As seen in FIG. 4E, at fifth stage 90 in cycle 82, first delivery cylinder DCl executes a suction stroke. First suction poppet valve SPV1 opens in response to signals from controller 30 to poppet block 16 such that material is pulled into first delivery cylinder DCl through first suction poppet valve SPV1 as first ram R1 retracts. First discharge poppet valve DPV 1 remains closed. Second delivery cylinder DC2 continues to execute the pressure stroke, or the discharge stroke. Second discharge poppet valve DPV2 is open, material exiting second delivery cylinder DC2 through second discharge poppet valve DPV2. Second suction poppet valve SPV2 remains closed.

As seen in FIG. 4F, sixth stage 92 in cycle 82, the piston of first delivery cylinder DCl has executed the suction stroke such that first ram R1 is fully retracted and is located at the beginning of a compression stroke. The linear position of first ram R1 is determined by linear position sensor LI and controller 30. First suction poppet valve SPV1 closes in response to hydraulic fluid sent from poppet block 16 by controller 30, and first discharge poppet valve DPV1 remains closed. Second delivery cylinder DC2 continues to execute the pressure stroke. Second discharge poppet valve DPV2 is open such that material from second delivery cylinder DC2 continues to be discharged through second discharge poppet valve DPV2. Second suction poppet valve SPV2 remains closed.

As seen in FIG. 4G, at seventh stage 94 in cycle 82, first delivery cylinder DCl executes a compression stroke. Controller 30 directs hydraulic fluid through HPU 22 such that first ram R1 of first delivery cylinder DCl begins to extend, building the pressure in first delivery cylinder DCl as first suction poppet valve SPV1, and first discharge poppet valve DPV1 remain closed. During the compression stroke, the pressure in first delivery cylinder DCl increases to just below the pressure in second delivery cylinder DC2, or just below the pressure required to open first discharge poppet valve DPV1. First delivery cylinder DCl holds until second delivery cylinder DC2 is ready for changeover. Second delivery cylinder DC2 continues the pressure stroke such that second ram R2 of second delivery cylinder continues to extend. Second discharge poppet valve DPV2 remains open and second suction poppet valve SPV2 remains closed, material continuing to discharge from second delivery cylinder DC2.

As seen in FIG. 4H, at eighth stage 96 in cycle 82, second deliver cylinder DC2 continues the pressure stroke and has reached the changeover position. First delivery cylinder DC1 and second delivery cylinder DC2 undergo changeover simultaneously from second delivery cylinder DC2 to first delivery cylinder DC1. Changeover is initiated by controller 30 when pressure information from first pressure sensor PS 1 and second pressure sensor PS2 indicates that the pressures in first delivery cylinder DC1 and second delivery cylinder DC2 are almost equal, and second linear position sensor L2 signals to controller that second drive piston DRP2 is nearing completion of the discharge stroke, or at the changeover position. Controller 30 sends signals to poppet block 16 and HPU 22. Second suction poppet valve SPV2 remains closed and second discharge poppet valve DPV2 remains open. First delivery cylinder DC1 begins to execute a pressure stroke at the changeover. First suction poppet valve SPV 1 remains closed, and first discharge poppet valve DPV1 opens in response to hydraulic fluid from poppet block 16, coordinated by controller 30. The pressure in first delivery cylinder DC1 has reached full system pressure, the pressure in first delivery cylinder DC1 being sufficient to open first discharge poppet valve DPV 1 and begin the discharge stroke. The pressure in first delivery cylinder is equal to the pressure in second delivery cylinder DC2. Material is discharged from first delivery cylinder DC1 and second delivery cylinder DC2 during the changeover from second pump PMP2 to first pump PMP1. During changeover, both second delivery cylinder DC2 and first delivery cylinder DC1 are executing a pressure stroke, and there is no pressure disruption.

As seen in FIG. 41, at ninth stage 98 in cycle 82, second delivery cylinder DC2 ends the pressure stroke, discharge stroke. Second ram R2 reaches full extension and stops, de-pressurizing second delivery cylinder DC2. Position information for second delivery cylinder DC2 is gathered from second drive cylinder DRC2 by second linear position sensor L2 and sent to controller 30, and pressure information for second delivery cylinder DC2 is gathered from second drive cylinder DRC2 by second pressure sensor PSI and sent to controller. Controller 30 signals second discharge poppet valve DPV2 to close and second suction poppet valve SPV2 to remain closed. First delivery cylinder DC1 continues to execute the pressure stroke, or discharge stroke, in response to signals sent by controller 30 to HPU 22 based on the position and pressure in first delivery cylinder DC1, gathered from first drive cylinder DRCI by first linear position sensor LI and first pressure sensor PSI and sent to controller 30. Material is discharged from first delivery cylinder DC1 through first discharge popper valve DPV1. The changeover from second delivery cylinder DC2 to first delivery cylinder DC1 is complete.

As seen in FIG. 41, at tenth stage 100 in cycle 82, second delivery cylinder DC2 executes a suction stroke. Second suction poppet valve SPV2 opens in response to signals from controller 30 to poppet block 16 such that material is pulled into second delivery cylinder DC2 through second suction poppet valve SPV2 as second ram R2 retracts. Second discharge poppet valve DPV2 remains closed. First delivery cylinder DC1 continues to execute the pressure stroke, or discharge stroke. First discharge poppet valve DPV1 is open, material exiting first delivery cylinder DC1 through first discharge poppet valve DPV1. First suction poppet valve SPV1 remains closed.

As seen in FIG. 4K, at eleventh stage 102 in cycle 82, the piston of second delivery cylinder DC2 has executed the suction stroke such that second ram R2 is fully retracted and is located at the beginning of a compression stroke. The linear position of second ram R2 is determined by linear position sensor L2 and controller 30. Second suction poppet valve SPV2 closes in response to hydraulic fluid sent from poppet block 16 by controller 30, and second discharge poppet valve DPV1 remains closed. First delivery cylinder DC1 continues to execute the pressure stroke. First discharge poppet valve DPV1 is open such that material from first delivery cylinder DC1 continues to be discharged through first discharge poppet valve DPV1. First suction poppet valve SPV1 remains closed.

Following stage 102, cycle 82 repeats, beginning again with first stage 80 shown in and described with respect to FIG. 4A.

Separating the operation of first delivery cylinder DC1 and second delivery cylinder DC2 allows for individual control of first delivery cylinder DC1 and section delivery cylinder DC2. Each of first delivery cylinder DC1 and second delivery cylinder DC2 completes a suction stroke and completes a compression stroke and holds before the other delivery cylinder ends a pressure stroke. As a result, the suction strokes take place more quickly than the pressure strokes. Each of first delivery cylinder DC1 and second delivery cylinder DC2 also engages in a compression stroke so that the pressure within the delivery cylinder is near the pressure required for the pressure stroke before the other delivery cylinder completes its pressure stroke. Both the suction stroke and the compression stroke and a hold are completed before the pressure stroke of the opposite cylinder is completed. As a result, there is a negligible drop in pressure during the changeovers between first delivery cylinder DC1 and second delivery cylinder DC2, and the pipeline pulsation is reduced to a nearly undetectable operation.

Start-Up Cycle Piston Positions - Figures 5A-5C

FIGS. 5A-5C illustrate stages in start-up cycle 106 of multi-piston pump 10. Multi-piston pump 10 includes first delivery cylinder DC1, second delivery cylinder DC2, first discharge poppet valve DPV1, first suction poppet valve SPV1, second discharge poppet valve DPV2, and second suction poppet valve SPV2. Start-up cycle 106 of FIGS. 5A, 5B, and 5C is described above with respect to steps 38, 40, and 42 in FIG. 3A. Startup cycle 106 takes place when multi-piston pump 10 is initially powered. Start-up cycle 106 is followed by a recursive cycle 82. In alternate embodiments, multi-piston pump 10 may initialize with any suitable start-up cycle. For example, start-up cycle 106 may not include retraction of both first delivery cylinder DC1 and second delivery cylinder DC2. Multi-piston pump 10 may engage only one of first delivery cylinder DC1 or second delivery cylinder DC2 at start-up.

Hydraulic Power Unit Status Display - Figure 6

FIG. 6 is a partial schematic view of multi-piston pump 10 showing hydraulic power unit status display 112 of hydraulic power unit 22. Multi -piston pump 10 includes hydraulic power unit 22 and controller 30. HPU 22 includes hydraulic power unit status display 112.

Hydraulic power unit status display 112 shows information related to multipiston pump 10. Motor 1 and motor 2 are part of hydraulic power unit 22 and drive pumps that yield pressurized hydraulic fluid. Hydraulic power unit status display 112 shows whether motor 1 and/or motor 2 are online or offline and whether the pumps are enabled or disabled, and whether the pumps are on or off. Start hydraulic flow calculation while pumping is an input on hydraulic power unit status display 112 that can be used to start hydraulic flow calculation of motor 1 and/or motor 2. Menu, pump stop, pressure decrease, pump speed percentage, pressure increase, pump start, and alarm history are input buttons on hydraulic power unit status display 112. Pump stop can be activated to stop multi-piston pump 10. Pressure decrease can be activated to decrease the pressure in first pump PMP1 and/or second PMP2, based on the pump selected on hydraulic power unit status display 112. Pump speed percentage can be activated to increase or decrease the speed of first pump PMP1 and/or second pump PMP2. Pressure increase can be activated to increase the pressure in first pump PMP1 and/or PMP2, based on the pump selected on hydraulic power unit status display 112. Pump start can be activated to start multi-piston pump 10. Menu and alarm history can be selected to display menu options and a log of previous activated alarms for multi-piston pump 10.

The statuses of the HPU motor 1, HPU motor 2, oil cooler 1, and oil cooler 2 are displayed on the left column of hydraulic power unit status display 112. The left column also shows the oil temperature, oil level, cylinder 1 hydraulic oil pressure, cylinder 2 hydraulic oil pressure, and accumulator pressure. The runtime hours for each of the motors, the number of starts for each of the motors, the numerical value of pump speed percentage, a count of the strokes per minute, the gallons per minute at the pump speed percentage for each cylinder is displayed on the right column of hydraulic power unit status display 112. In alternate embodiments, the inputs and displays can be in any suitable location on hydraulic power unit status display 112.

Controller 30 receives sensor signals, taking in information and providing outputs to HPU 22 and poppet block 16. Hydraulic power unit status display 112 is a visual display of outputs from controller 30 related to the functioning of multi-piston pump 10 for diagnostics and monitoring of multi-piston pump 10. Hydraulic power unit status display 112 also acts as a user interface that can receive user inputs, via touch screen or any other suitable control, and send signals to controller 30 to execute various functions and tests of multi-piston pump 10. As such, hydraulic power unit status display 112 is bi-directional to display pump information and also receive user input, enabling both functionality and pump monitoring and diagnostics of multi-piston pump 10.

Pump Diagnostic Display - Figure 7

FIG. 7 is a partial schematic view of multi-piston pump 10 showing pump diagnostic display 114 of hydraulic power unit 22. Multi-piston pump 10 includes hydraulic power unit 22, controller 30. HPU 22 includes pump diagnostic display 114.

Pump diagnostic display 114 displays drift pressure, hydraulic pressure, cylinder speed, cylinder position, and cylinder drift position for each of pump 1 and pump 2 of multi-piston pump 10. Pump diagnostic display 114 also includes inputs for selecting and activating diagnostic tests, including poppet seat leak pressure calibration, poppet leak test, cylinder position test, hydraulic pump leak down test, and hydraulic piston seal test. Pump diagnostic display 114 displays which diagnostic tests are running and which diagnostic modes active or inactive. Pump diagnostic display 114 also displays test results, including poppet seat pressure, poppet leak pressure, cylinder target position percentage, hydraulic bleed down test pressure, and hydraulic piston seal test pressure. Controller 30 receives sensor signals, taking in information and providing outputs to HPU 22 and poppet block 16. HPU 22 can use the information obtained by controller 30 and output through controller 30 to conduct diagnostic tests on multi-piston pump. Controller 30 coordinates operations of first pump PMP1 and second pump PMP2 based upon sensor inputs of position information and pressure information of first pump PMP1 and second pump PMP2 to execute one or more diagnostic test in response to input received by controller 30. Pump diagnostic display 114 is a visual display of outputs from controller 30 related to the diagnostic tests that can be used with multi-piston pump 10, including diagnostic test results. Pump diagnostic display 114 also acts as a user interface that can receive user inputs, via touch screen or any other suitable control, for indicating which of various diagnostic tests to run and send signals to controller 30 to execute those tests. As such, pump diagnostic display 114 is bi-directional to display pump information allowing a user to see how multi-piston pump 10 is performing and also receive user input, enabling monitoring and diagnostic testing of multi -piston pump 10.

Poppet Seat Leak Pressure Calibration Test - Figure 8

FIG. 8 is a flowchart of poppet seat leak pressure calibration test 116 showing steps 118-131. Poppet seat leak pressure calibration test 116 includes steps 118- 131.

At step 118, poppet seat leak pressure calibration test 116 starts with user test selection input at pump diagnostic display 114, as shown in FIG. 7.

At step 120, controller 30 signals first suction poppet valve SPV1 and second suction poppet valve SPV2 open in response to the selection at pump diagnostic display 114. First suction poppet control solenoid SPCS 1 and second suction poppet control solenoid SPCS2 turn on in response to signals received from controller 30, which directs hydraulic fluid via first suction poppet rod fluid line SPRFL1 and second suction poppet rod fluid line SPRFL2 to the rod side of first suction poppet valve SPV1 and the rod side of second suction poppet valve SPV2, respectively. First discharge poppet valve DPV1 and second discharge poppet valve DPV2 close. First discharge poppet control solenoid DPCS 1 and second discharge poppet control solenoid DPCS2 turn off in response to signals from controller 30. The hydraulic fluid of first drive cylinder DRCI and second drive cylinder DRC2 is directed to the rod side of both cylinders by controller 30 to push each of first drive piston DRP1 and second drive piston DRP2 to a retracted position. As a result, first ram R1 of first delivery cylinder DC1 and second ram R2 of second delivery cylinder DC2 also move rearwardly to retract to the initialization position. As first ram R1 of first delivery cylinder DC1 and second ram R2 second delivery cylinder DC2 retract to the starting positions, first delivery cylinder DC1 undergoes initial filling of material through first suction poppet valve SPV1, and second delivery cylinder DC2 undergoes initial filling of material through second suction poppet valve SPV2, as seen in FIG. 5B.

At step 122 first suction poppet valve SPV1, first discharge poppet valve DPV 1 , second suction poppet valve SPV2, and second discharge poppet valve DPV2 close. First discharge poppet control solenoid DPCS1, first suction poppet control solenoid SPCS1 , second discharge poppet control solenoid DPCS2, and second suction poppet control solenoid SPCS2 are turned off by controller 30. First linear position sensor LI senses the position of first drive piston DRP1 and first ram R1 of first drive cylinder DRCI and delivers the sensed signal to controller 30, which records the position of first ram Rl. Second linear position sensor L2 senses the position of second drive piston DRP2 and second ram R2 of second drive cylinder DRC2 and delivers the sensed signal to controller 30, which records the position of second ram R2. The hydraulic pressure of first delivery cylinder DC1 and second delivery cylinder DC2 is at a minimum level as pistons are at the initialization position. Controller 30 then pressurizes the piston side of first drive cylinder DRP1 and piston side of second drive cylinder DRP2 by signaling first piston side pressure PSP1 and second piston side pressure PSP2 to deliver hydraulic fluid via first piston side pressure fluid line PSFL1 and second piston side pressure fluid line PSFL2, respectively. As such, controller 30 also signals first rod side tank RST1 and second rod side tank RST2 to remove hydraulic fluid via first rod side tank fluid line RSFL1 and second rod side tank fluid line RSFL2, respectively, to allow for movement of first ram Rl and second ram R2. As first suction poppet valve SPV1, first discharge poppet valve DPV1, second suction poppet valve SPV2, and second discharge poppet valve DPV2 are all closed, hydraulic fluid is pushing against first drive piston DRP1 and second drive piston DRP2, increasing the hydraulic pressure in first delivery cylinder DC1 and second delivery cylinder DC2, respectively, at a set time interval.

At step 124, controller 30 determines whether first ram Rl of first delivery cylinder DC1 has moved in excess of the movement threshold over the time interval. Controller 30 also determines whether second ram R2 of second delivery cylinder DC2 has moved in excess of the movement threshold over the time interval. The movement threshold over time interval is a user settable threshold that indicates the distance the delivery piston should move, or the expected change of position of the ram, over a given period of time. If first ram Rl and second ram R2 have not moved in excess of the movement threshold, poppet seat leak pressure calibration test 116 proceeds to step 126. If first ram R1 and second ram R2 have moved in excess of the movement threshold, poppet seat leak pressure calibration test 116 proceeds to step 128.

At step 126, controller 30 signals incremental increases in hydraulic pressure such that hydraulic fluid is incrementally delivered to the piston sides of first drive cylinder DRCI and second drive cylinder DRC2 at a time interval set at controller 30 using pump diagnostic display 114, shown in FIG. 7. As such, HPU 22 delivers hydraulic fluid via first piston side pressure PSP1 , second piston side pressure PSP2, first piston side pressure fluid line PSFL1, and second piston side pressure fluid line PSFL2 to the piston sides of first drive cylinder DRCI and second drive cylinder DRC2, respectively. As such, the pressure in first delivery cylinder DC1 and second delivery cylinder DC2 is continually increased at each time interval.

At step 128, controller 30 determines the pressure at which movement of first ram R1 and second ram R2 has occurred . The positions of first ram R1 and second ram R2 are monitored by first linear position sensor LI and second linear position sensor L2 as pressure increases in first delivery cylinder DC1 and second delivery cylinder DC2 until first ram R1 and second ram R2 moves, respectively. The lower of the pressure of first delivery cylinder DC1 and the pressure of the second delivery cylinder DC2 is recorded and stored by controller 30 as the poppet leak test pressure at pump diagnostic display 114, as shown in FIG. 7. Poppet leak test pressure PLTP is the pressure required for the material within first delivery cylinder DC1 or second delivery cylinder DC2 to unseat and leak past one or more of first discharge poppet valve DPV 1 , first suction poppet valve SPV2, second discharge poppet valve DPV2, and second suction poppet valve SPV2.

At step 130, poppet seat leak pressure calibration test 116 is stopped by controller 30.

At step 131, test results from poppet leak pressure calibration test 116 are displayed on pump diagnostic display 114. By using the first linear position sensor LI and the second linear position sensor L2 to calibrate the position of the first ram R1 and the second ram R2 and monitor drift of first ram R1 and second R2 as the pressure in first delivery cylinder DC1 and second delivery cylinder DC2 increases, the poppet leak test pressure, or pressure required to unseat a healthy discharge poppet valve, can be determined. Poppet seat leak pressure calibration test 116 identifies poppet leak test pressure for use in poppet seat leak test 132. Poppet seat leak pressure calibration test 116 can also be used as a diagnostic tool to ensure that the pump is functioning optimally. For example, poppet seat leak pressure calibration test 116 can be used to confirm whether both first drive cylinder DRCI and second drive cylinder DRC2 are driving simultaneously.

Poppet Seat Leak Test - Figure 9

FIG. 9 is a flow chart of poppet seat leak test 132 showing steps 134-147. Poppet seat leak test 132 includes steps 134-147.

At step 134, poppet leak test 132 starts with user test selection input at pump diagnostic display 114, as shown in FIG. 7.

At step 136, first suction poppet valve SPV1 and second suction poppet valve SPV2 open in response to the selection at controller 30. First suction poppet control solenoid SPCS 1 and second suction poppet control solenoid SPCS2 turn on in response to signals received from controller 30 to direct hydraulic fluid via first suction poppet rod fluid line SPRFL1 and second suction poppet rod fluid line SPRFL2 to the rod side of first suction poppet valve SPV1 and the rod side of second suction poppet valve SPV2, respectively. First discharge poppet valve DPV 1 and second discharge poppet valve DPV2 close. First discharge poppet control solenoid DPCS 1 and second discharge poppet control solenoid DPCS2 turn off in response to signals from controller 30. The hydraulic fluid of first drive cylinder DRCI and second drive cylinder DRC2 is directed to the rod side of both cylinders by controller 30 to push each of first drive piston DRP1 and second drive piston DRP2 to a retracted position. As a result, first ram R1 of first delivery cylinder DC1 and second ram R2 of second delivery cylinder DC2 also move rearwardly to retract to the initialization position. As first ram R1 of first delivery cylinder DC1 and second ram R2 second delivery cylinder DC2 retract to the starting positions, first delivery cylinder DC1 undergoes initial filling of material through first suction poppet valve SPV1, and second delivery cylinder DC2 undergoes initial filling of material through second suction poppet valve SPV2, as seen in FIG. 5B.

At step 138, first suction poppet valve SPV1, first discharge poppet valve DPV 1 , second suction poppet valve SPV2, and second discharge poppet valve DPV2 close. First discharge poppet control solenoid DPCS1, first suction poppet control solenoid SPCS 1, second discharge poppet control solenoid DPCS2, and second suction poppet control solenoid SPCS2 are turned off by controller 30. First linear position sensor LI senses the position of first ram R1 of first delivery cylinder DC1 and delivers the sensed signal to controller 30, which records the position of first ram Rl. Second linear position sensor L2 senses the position of second ram R2 of second delivery cylinder DC2 and delivers the sensed signal to controller 30, which records the position of second ram R2. Controller 30 signals to HPU22 to deliver hydraulic fluid until the pressure of first delivery cylinder DC1 and the pressure of second delivery cylinder DC2, which is delivered to controller 30 by first pressure sensor PSI and second pressure sensor PS2, is equal to just below poppet leak test pressure PLTP. The hydraulic pressure of first delivery cylinder DC1 and second delivery cylinder DC2 is at a minimum level as pistons are at the initialization position. Controller 30 then pressurizes the piston side of first drive cylinder DRP1 and piston side of second drive cylinder DRP2 by signaling first piston side pressure PSP1 and second piston side pressure PSP2 to deliver hydraulic fluid via first piston side pressure fluid line PSFL1 and second piston side pressure fluid line PSFL2, respectively. As such, controller 30 also signals first rod side tank RST1 and second rod side tank RST2 to remove hydraulic fluid via first rod side tank fluid line RSFL1 and second rod side tank fluid line RSFL2, respectively, to allow for movement of first ram R1 and second ram R2. As first suction poppet valve SPV1, first discharge poppet valve DPV1, second suction poppet valve SPV2, and second discharge poppet valve DPV2 are all closed, hydraulic fluid is pushing against first drive piston DRP1 and second drive piston DRP1, increasing the hydraulic pressure in first delivery cylinder DC1 and second delivery cylinder DC2, respectively, at a set time interval. First linear position sensor LI and second linear position sensor L2 monitor the positions of first ram R1 and second ram R2, respectively, before and during the hydraulic pressure increase.

At step 140, controller 30 determines whether first ram R1 or second ram R2 has moved beyond, or exceeded, the threshold of the expected change of position over the set time interval (i.e. whether first ram R1 or second ram R2 has drifted) by gathering position information of first delivery piston DL1 and second delivery piston DL2 from first linear position sensor LI and second linear position sensor L2, respectively. If not, poppet seat leak test 132 proceeds to step 142. If so, poppet seat leak test 132 proceeds to step 144.

At step 142, controller 30 conveys sensed signals to pump diagnostic display 114 to convey that the first discharge poppet valve DPV1, first suction poppet valve SPV1, second discharge poppet valve DPV2, and second suction poppet valve SPV2 have passed poppet leak test.

At step 144, controller 30 conveys that one or more of the first discharge poppet valve DPV 1 , first suction poppet valve SPV 1 , second discharge poppet valve DPV2, and second suction poppet valve SPV2 have not passed, or failed, the poppet seat leak test 132 to pump diagnostic display 114. As first delivery cylinder DC1 is independent from second delivery cylinder DC2, controller 30 also conveys which of first delivery cylinder DC1 and second delivery cylinder DC2 contain the failed poppet valves.

At step 146, poppet seat leak test 132 is stopped by controller 30.

At step 147, the pass/fail test results from poppet seat leak test 132 are displayed on pump diagnostic display 114. By using a hydraulic pressure lower than the pressure required to move the first discharge poppet valve DPV 1 or the first suction poppet valve SPV1 and the second discharge poppet valve DPV2 or the second suction poppet valve SPV2 (the poppet leak test pressure described above with respect to FIG. 8), first ram R1 and second ram R2 are pressurized while the poppet valves DPV 1 , SPV 1 , DPV2, SPV2 are held closed. As such, first delivery cylinder DC1 and second delivery cylinder DC2 can be monitored for drift to determine whether any of the poppet valves DPV1, SPV1, DPV2, SPV2 are failing. As such, poppet seat leak test 132 is used to identify potential leaks in first delivery cylinder DC 1 and/or second delivery cylinder DC2 without requiring complete disassembly and visual inspection of multi-piston pump 10. As a result, poppet seat leak test 132 allows for quick maintenance of multi-piston pump 10 and earlier identification of potential leaks rather than failure of the entirety of multi-piston pump 10.

Cylinder Position Test - Figure 10

FIG. 10 is a flow chart of cylinder position test 148 showing steps 150-173. Cylinder position test 148 includes steps 150-173.

At step 150, cylinder position test 148 starts.

At step 152, the known target position percentage for movement of first ram R1 and second ram R2 of first delivery cylinder DC1 and second delivery cylinder DC2, respectively, is entered by a user at pump diagnostic display 114, as shown in FIG. 7, and received by controller 30.

At step 154, cylinder position test 148 is started with user test selection input at pump diagnostic display 114, as shown in FIG. 7, and received by controller 30.

At step 156, controller 30 determines whether first ram R1 of first delivery cylinder DC1 and/or second ram R2 of second delivery cylinder DC2 need to extend to achieve the target location based on the target position percentage selected. First linear position sensor LI and second linear position sensor L2 send position information regarding first ram R1 and second ram R2, respectively, to controller 30. If so, cylinder position test 148 proceeds to step 158. If not, cylinder position test 148 proceeds to step 160. At step 158, first ram R1 of first delivery cylinder DC1 and/or second ram R2 of second delivery cylinder DC2 are extended by controller 30 such that first ram R1 and/or second ram R2 move forward. As such, controller 30 signals to HPU 22 to deliver hydraulic fluid to the piston side of first drive cylinder DRCI and/or the piston side of second drive cylinder DRC2.

At step 160, controller 30 determines whether first ram R1 of first delivery cylinder DC1 and/or second ram R2 of second delivery cylinder DC2 need to retract to achieve the target location based on the target position percentage selected. If so, cylinder position test 148 proceeds to step 162. If not, cylinder position test 148 proceeds to step 164.

At step 162, first ram R1 of first delivery cylinder DC1 and/or second ram R2 of second delivery cylinder DC2 are retracted by controller 30. As such, controller 30 signals to HPU 22 to deliver hydraulic fluid to the rod side first drive cylinder DRC 1 and/or the rod side second drive cylinder DRC2. First ram R1 and/or second ram R2 move rearwardly.

At step 164, controller 30 determines whether the first cylinder position indicator and/or the second cylinder position indicator on pump diagnostic display 114 of FIG. 7 matches the target location, as identified by first linear position sensor LI and second linear position sensor L2. If not, cylinder position test 148 proceeds to step 166. If so, cylinder position test 148 proceeds to step 168.

At step 166, controller 30 conveys signals to pump diagnostic display 114 that cylinder position test 148 resulted in a fail.

At step 168, controller 30 determines whether the actual physical position of first ram R1 of first delivery cylinder DC1 and/or second ram R2 of second delivery cylinder DC2, as identified by user observation, matches the target location identified by first linear position sensor LI and second linear position sensor L2 on pump diagnostic display 114. If not, cylinder position test 148 proceeds to step 166. If so, cylinder position test 148 proceeds to step 170.

At step 170, controller 30 conveys signals to pump diagnostic display 114 that cylinder position test 148 resulted in a pass.

At step 172, cylinder position test 148 is stopped by controller 30.

At step 173, the pass/fail test results from cylinder position test 148 is displayed on pump diagnostic display 114. Cylinder position test 148 is used to verify the accuracy of first linear position sensor LI and second linear position sensor L2. As such, the actual positions of first delivery cylinder DC1 and second delivery cylinder DC2 correspond to the values entered into and displayed on pump diagnostic display 114, as shown in FIG. 7, to prevent damage to and ensure accuracy of multi-piston pump 10. Additionally, first linear position sensor LI and second linear position sensor L2 provides the ability to command multi-piston pump 10 to a specified position for maintenance and troubleshooting assistance.

Hydraulic Pump Leak Down Test - Figure 11

FIG. 1 1 is a flow chart of hydraulic pump leak down test 174 showing steps 176-193. Hydraulic pump leak down test 174 includes steps 176-193.

At step 176, hydraulic pump leak down test 174 starts.

At step 178, controller 30 instructs the operator to close hydraulic pressure ball valves on HPU 22 for first pressure Pl and second pressure P2.

At step 180, hydraulic bleed down test pressure, which is the pressure at which hydraulic pump leak down test 174 will be performed, is entered at pump diagnostic display 114, shown in FIG. 7. The hydraulic bleed down test pressure must be in excess of a hydraulic relief setting, or high enough to force a relief valve open, to allow oil to flow into hydraulic power unit 22, so that a hydraulic pump swash plate of HPU 22 will not destroke.

At step 182, a pump group is selected from pressure one (pl) available pumps and pressure two (p2) available pumps of hydraulic power unit 22. The available pump or pumps are selected on hydraulic power unit status display 112, as seen in FIG. 6. Total horsepower of the selected pump group cannot be in excess of the motor horsepower associated with the pump group or motor overload will occur.

At step 184, hydraulic pump leak down test 176 begins via user test selection input at pump diagnostic display 114, as shown in FIG. 7.

At step 186, a hydraulic pressure regulator or compensator on hydraulic power unit 22 is set to a desired test pressure at pump diagnostic display 114, as shown in FIG. 7, and pressurized to the desired hydraulic pressure.

At step 188, pump hydraulic output is set to 100 percent at hydraulic power unit status display 112. During step 188, hydraulic output is gradually stepped down to minimum speed.

At step 190, hydraulic pressure is monitored using trend data to determine if the hydraulic pressure of the hydraulic pressure regulator decreases before the minimum speed of the hydraulic pump is reached. Controller 30 determines whether the hydraulic power unit passed or failed the test. If the hydraulic pressure of the hydraulic pressure regulator does not decrease before the minimum speed of the hydraulic pump is reached, hydraulic pump leak down test 174 results in a pass. If the hydraulic pressure of the hydraulic pressure regulator decreases before the minimum speed of the hydraulic pump is reached, hydraulic pump leak down test 174 results in a fail.

At step 192, hydraulic pump leak down test 174 is stopped by controller 30.

At step 193, the pass/fail test results from hydraulic pump leak down test 174 are displayed on pump diagnostic display 1 14. Hydraulic pump leak down test 174 identifies symptoms of decreased output. Hydraulic pump leak down test 174 checks whether pressure is maintained at low speeds, when the pump is slowing down. If hydraulic pump leak down test 174 fails, HPU 22 of multi-piston pump 10 can undergo the necessary internal inspections.

Hydraulic Piston Seal Test - Figure 12

FIG. 12 is a flow chart of hydraulic piston seal test 194 showing steps 196- 221. Hydraulic piston seal test 194 includes steps 196-221.

At step 196, hydraulic piston seal test 194 starts. The test is performed on one piston at a time.

At step 198, a selection is made, through user interface 31, of the piston seal to be tested. In addition, a selection is made whether hydraulic pressure will be used to pressurize the piston side or the rod side of drive cylinder DRCI or DRC2. If the rod side is pressurized, the flow of hydraulic fluid from the piston side is blocked during the test. Conversely, if the piston side is pressurized, the rod side is blocked during the test.

At step 200, a hydraulic piston seal test pressure is entered at pump diagnostic display 114, as shown in FIG. 7.

At step 202, hydraulic piston seal test 194 begins via user test selection input at pump diagnostic display 114, as shown in FIG. 7.

At step 204, hydraulic power unit 22 is commanded by controller 30 to extend or retract the selected piston to move the piston to a central target position which will allow for drift of the piston within the cylinder during pressurization if the piston seal leaks.

At step 206, controller 30 determines whether the piston has reached a predetermined target position. If so, hydraulic piston seal test 194 proceeds to step 208. If not, hydraulic piston seal test 194 returns to steps 204, and steps 204 and 206 are repeated until the piston is at the target position. At step 208, the piston is at the target position. Based upon whether the piston side or the rod side is to be pressurized (see step 198), either step 210 or step 212 follows.

At step 210, controller 30 signals HPU 22 to apply hydraulic pressure to the piston side while the rod side is blocked to prevent flow from the rod side to the tank exhaust.

Alternatively, at step 212, controller 30 signals to HPU 22 to apply hydraulic pressure to the rod side while flow from piston side to a tank exhaust is blocked.

At step 214, controller 30 determines whether the piston position moved in excess of a threshold value from the target position. If there is a leak in the piston seal, hydraulic fluid will flow from the rod side to the piston side, which causes the piston to move in the forward extending direction. The movement is sensed by the corresponding linear position sensor LI or L2. If so, hydraulic piston seal test 194 proceeds to step 216. If the piston has not moved in excess of the threshold value, hydraulic piston seal test 194 proceeds to step 218.

At step 216, controller 30 conveys signals to pump diagnostic display 114 that the piston seal failed the hydraulic piston seal test 194.

At step 218, controller 30 conveys signals to pump diagnostic display 114 that the piston seal passed the hydraulic piston seal test 194.

At step 220, hydraulic piston seal test 194 is stopped by controller 30.

At step 221, the pass/fail test results from hydraulic piston seal test 194 are displayed on pump diagnostic display 114. Hydraulic piston seal test 194 uses first linear position sensor LI and second linear position sensor L2 as a feedback tool. By stopping, or “corking,” blocking the rod sides of first drive cylinder DRCI and second drive cylinder DRC2 and activating first piston side pressure PSP1 and/or second piston side pressure PSP2, hydraulic piston seal test 194 determines whether there is a leak on the seal of first drive piston DRP1 or second drive piston DRP2. If there is no leak in the seal, the piston cannot move, indicating that the seal is still functioning. If hydraulic piston seal test 194 indicates a piston seal failure, the seal can be replaced earlier and prevent failure of multipiston pump 10. The test can then be repeated for the other piston.

While the invention has been described with reference to an exemplary embodiment(s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.