TECHNICAL FIELD

The present invention relates to a pumping device, and more particularly to a flow control system for the pumping device.

BACKG ROUND

Pumping devices or pump apparatuses such as, electric pressure pumps, pressure tank units, or fuel-powered pressure pumps, which are generally used for various types of water management applications including gardening, agriculture, industrial or domestic water supply, include a flow control system. A typical flow control system includes a non-return valve or one-way valve having a closing member movable between an open position and a closed position to allow fluid (e.g. water) flow in only one direction. The non-return valve may include a restoring means, such as a spring, to apply a restoring force on the closing member to maintain the closing member in the closed position. Thus, in an absence of a hydrostatic fluid pressure in the pumping device the nonreturn valve prevents any backflow of the fluid or inflow of air into the pumping device or suction line.

In order to ensure a smooth intake of the fluid from a fluid reservoir, such as water tank or water-well, generally after a new installation of the pumping device or after performing a maintenance operation on the pumping device, an actuation mechanism is provided. The actuation mechanism is configured to forcibly move the closing member of the nonreturn valve to the open position to facilitate the intake of the fluid through the suction line. The actuation mechanism may apply a counteracting force on the closing member which acts against the restoring force of the non-return valve, so that already present air in the pumping device can flow out and an inflow of the fluid into the pumping device is effectively facilitated. Conventionally, the actuation mechanism includes an actuation element embodied as a lever which is pivotally connected to the closing member of the non-return valve. The actuation element is movable to an operative position from an inoperative position to apply the required counteracting force to move the closing member to the open position, particularly during a starting-up of the pumping device. During the starting-up of the pumping device, an operator is required to manually shift the actuation element from the inoperative position to the operative position. Further, after a pre-set hydrostatic fluid pressure builds in the pumping device the operator has to manually shift the actuation element to the inoperative position from the operative position to release the counteracting force on the closing member of the non-return valve. This type of flow control system essentially requires a regular manual intervention by the operator during the starting-up and a normal working state of the pumping device.

European Patent Application No. 1 ,767,789 A2 discloses a fluid control system, which allows a simplified starting-up of the pumping device. The disclosed fluid control system includes a non-return valve and an actuation mechanism having an actuation element, such as control pin movable to an operative position from an inoperative position to apply the counteracting force to move a closing member of the nonreturn valve to an open position. The fluid control system ensures that once a pre-set hydrostatic fluid pressure is reached in the pumping device, under the action of the hydrostatic fluid pressure the actuation element shifts to the inoperative position, without any manual intervention required from the operator. This automatically releases the counteracting force on the closing member of the non-return valve. Even though, in this case during starting-up of the pumping device, generally after the new installation of the pumping device or after performing the maintenance operation on the pumping device, the operator is required to manually shift the actuation element to the operative position from the inoperative position. Therefore, as aforementioned, the actuation element is inevitably required to be manually shifted to the operative position to start- up the pumping device, failure to which may cause ineffective pumping operation and also may decrease the life of the pumping device in the long run.

Therefore, in light of the foregoing, there is a need for an improved flow control system for a pumping device or a pump apparatus.

SUMMARY

In view of the above, it is an objective of the present invention to solve or at least reduce the problems discussed above. The objective is at least partially achieved according to a pumping device or a pump apparatus according to an aspect of the present invention. The pumping device includes an inlet, an outlet, and a pump housing defining a pressure chamber which is in fluid communication with the inlet and the outlet. The inlet and the outlet may be further connected to a suction line and a discharge line, respectively. The pumping device further includes a flow control system having a non-return valve and an actuation mechanism. The non-return valve includes a closing member which is movable between an open position and a closed position to allow a unidirectional fluid flow, and the actuation mechanism includes an actuation element which is movable between an operative position and an inoperative position with respect to the closing member. In the operative position, the actuation element is configured to apply a counteracting force to move the closing member to the open position. Further, the actuation element is biased towards the operative position such that during the starting-up of the pumping device an operator is not required to manually shift the actuation element from the inoperative position to the operative position. Moreover, while the closing member is in the open position, any air already present in the pumping device can flow out and an inflow of the fluid into the pumping device is effectively facilitated.

Following the starting-up of the pumping system, during a normal working status of the pumping device the actuation element is configured to be moved to the inoperative position by a fluid pressure acting on the actuation element again without any sort of manual intervention from the operator. Moreover, while the actuation element is in the inoperative position the non-return valve automatically prevents the backflow of the fluid in the pressure chamber and/or the suction line. The actuation mechanism may include a positioning means such as spring which is configured to constantly bias the actuation element towards the operative position.

The flow control system may be disposed on the discharge line along with a pressure sensor and a flow sensor. The pressure sensor and the flow sensor are configured to monitor a fluid pressure and the fluid flow rate in the discharge line, respectively. A controller operatively connected to the pressure sensor and the flow sensor is configured to start an operation of the pumping device in case the fluid pressure in the discharge line drops below a threshold start-up pressure. Also, the controller is configured to stop an operation of the pumping device in case a fluid flow ceases due to an obstruction in discharge line. The flow sensor may be a Hall-effect sensor. According to an aspect of the present invention, if a tap or a faucet is connected to the discharge line and the operator closes the tap or the faucet, the non-return valve moves to the closed position to prevent the backflow of the fluid and simultaneously the controller stops the operation of the pumping device or the pump apparatus. Once the operator opens the tap or the faucet again the controller starts the operation of the pumping device or the pump apparatus and the non-return valve moves to the open position due the water flow caused by the pumping action. This provides a complete automatic operation of the pumping device or the pump apparatus without any manual intervention during the starting-up or the pump and/or the normal working status. BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in more detail with reference to the enclosed drawings, wherein: FIG. 1 is a block block diagram of a pumping device, according to an embodiment of the present invention;

FIG. 2 illustrates a perspective view of a pump apparatus, according to an embodiment of the present invention;

FIG. 3A is a partial sectional view of the pump apparatus of FIG. 2 about AA';

FIG. 3B is a partial sectional view of the pump apparatus of FIG. 2 about AA'; and

FIG. 3C is a partial sectional view of the pump apparatus of FIG. 2 about AA'.

DESCRIPTION OF EMBODI MENTS

The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which example embodiments of the invention incorporating one or more aspects of the present invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. For example, one or more aspects of the present invention can be utilized in other embodiments and even other types of structures and/or methods. In the drawings, like numbers refer to like elements.

FIG. 1 is a block diagram of a pumping device 100, according to an embodiment of the present invention. The pumping device 100 includes a rotodynamic pump 102, such as a centrifugal pump (hereinafter referred to as the pump 102), used for water management, in particular for use in house, garden and/or industrial application. In various other embodiments, the pump 102 may be a positive displacement pump, such as a gear pump, a screw pump, or the like. The pump 102 is configured to pressurize a fluid (e.g. water or rain-water or waste-water) from a fluid reservoir 104, such as a low pressure water tank, a water-well, a rainwater tank, a garden pond, and the like, and deliver a pressurized fluid at a fluid release control valve 106, such as a tap, a faucet, or a spigot. The fluid release control valve 106 may be used for further connecting the pumping device 100 to an irrigation sprinkler or watering hose for irrigation of lawns and/or crops. Alternatively, the fluid release control valve 106 may be used as sampling point for the pressurized fluid delivered by the pumping device 100.

The pump 102 includes a pump housing 108 which defines a pressure chamber 110. The pressure chamber 110 may house an impeller, a propeller, or a rotor which is driven by an electric motor 112. The electric motor 112 may be mechanically coupled to the impeller via a pump shaft. In an alternative embodiment, the pump 102 may include a fuel powered garden pumps used for rain-water management, domestic water supply, or waste-water discharge.

The pump 102 further includes at least one inlet 114 and at least one outlet 116 which are provided in fluid communication with the pressure chamber 110 and arranged for the intake and discharge of the fluid, respectively. A suction line 118 is connected to the inlet 114 and configured to supply a low-pressure fluid from the fluid reservoir 104 to the pressure chamber 110. The suction line 118 may include at least one suction hose/pipe which is connected to the inlet 114 via a hose connector and/or a pre-filter unit. Further, a discharge line 120 is connected to the outlet 116 and configured to deliver the pressurized fluid from the pressure chamber 110 at the fluid release control valve 106. The discharge line 120 may include at least one discharge hose/pipe which is connected to the outlet 116 via a hose connector.

According to an embodiment of the present invention, the pumping device 100 may include a flow control system 122. As illustrated in FIG. 1 , the flow control system 122 may be disposed on the discharge line 120 and configured to separate the pressure chamber 110 from the discharge line 120 while the fluid release control valve 106 is closed and/or an obstruction is present in the discharge line 120. Thus, the flow control system 122 prevents the fluid from draining back into the pressure chamber 110 and the suction line 118. Additionally, the flow control system 122 may be used to deliver the pressurized fluid at a pre-set pressure.

The flow control system 122 includes a non-return valve 124 that allows a unidirectional flow of the fluid from the pressure chamber 110 towards the fluid release control valve 106 and configured to block the discharge line 120 before the hydrostatic fluid pressure in the pressure chamber 110 drops below a hydrostatic fluid pressure in the discharge line 120 due to the switch off of the electric motor 112 of the pump 102. Thus, prevents a backflow of the fluid into the pressure chamber 110 and/or the suction line 118. In an embodiment, the non-return valve 124 may be a check valve having a closing member 126 embodied as a movable part, such as a substantially spherical ball, received in a valve seat 127. The closing member 126 is movable between an open position (as shown in FIG. 1 ) and a closed position. In the open position, the closing member 126 is moved away from the valve seat 127 to allow an uninterrupted fluid flow through the non-return valve 124. In the closed position, the closing member 126 is moved towards the valve seat 127 to create a seal and block the fluid flow through the non-return valve 124. The non-return valve 124 may also include a valve spring 129 to exert a restoring force RF (shown by arrow) on the closing member 126 and sealingly press the closing member 126 in the valve seat 127. This is due to the fact that in case the fluid release control valve 106 is closed and/or an obstruction is present in the discharge line 120 the hydrostatic fluid pressure in the discharge line 120 equals the hydrostatic fluid pressure in the pressure chamber 110 and thus closing member 126 is moved towards the valve seat 127 by restoring force RF by valve spring 129.

According to an embodiment of the present invention, the flow control system 122 includes an actuation mechanism 128 having an actuation element 130. The actuation element 130 is movable between an operative position (as shown in FIG. 1) and an inoperative position with respect to the closing member 126. In the operative position, the actuation element 130 may apply a counteracting force CF (shown by arrow) to move the closing member 126 away from the valve seat 127 and towards the open position. The counteracting force CF acting on the closing member 126 acts against the restoring force RF exerted by the valve spring 129 on the closing member 126. In the inoperative position of the actuation element 130, the counteracting force CF acting on the closing member 126 is released. Thus, while the actuation element 130 is in the inoperative position and while the hydrostatic fluid pressure in the pressure chamber 110 equals the hydrostatic fluid pressure in the discharge line 120 and there is no fluid flow, the closing member 126 can move towards the valve seat 127 under the action of the restoring force RF.

According to an aspect of the present invention the actuation element 130 is constantly biased towards the operative position to allow a smooth intake of the fluid from the fluid reservoir 104 during the starting- up of the pumping device 100, generally after a new installation of the pumping device 100 or after performing a maintenance operation on the pumping device 100. While the actuation element 130 is in the operative position and the closing member 126 is forcibly moved away from the valve seat 127 towards the open position, any air already present in the pumping device 100 can flow out and an inflow of the fluid into the pumping device 100 is effectively facilitated. Also, during the starting-up of the pumping device 100 an operator is not required to manually shift the actuation element 130 from the inoperative position to the operative position. According to an embodiment of the present invention, the actuation mechanism 128 may include a positioning means 132 which is configured to constantly bias the actuation element 130 towards the operative position. In the illustrated embodiment, the positioning means 132 is embodied a compression spring which is configured to transfer a spring force into the counteracting force CF acting on the closing member 126. In various alternative embodiments, the positioning means 132 may be embodied as an electrical, a pneumatic, a hydraulic or an electromechanical means which is operative connected to an electric controller and configured to bias the actuation element 130 towards the operative position. In an aspect of the present invention, the counteracting force CF exerted by the positioning means 132 is greater than the restoring force RF exerted by the valve spring 129 on the closing member 126. However, when the electric motor 112 of the pump 102 is switched off as no fluid flow is detected the hydrostatic fluid pressure in discharge line 120 is equal to or above a threshold start-up pressure. As a result of this, a combined force due to the restoring force RF and the hydrostatic fluid pressure acting on the closing member 126 is more than the counteracting force CF exerted by the positioning means 132. Thus the actuation element 130 is not able to move into the operative position in which the closing element 126 would be moved in open position.

According to an embodiment of the present invention, the counteracting force CF exerted by the positioning means 132 is pre-set at slightly less than the combined force of threshold start-up pressure in the pumping device 100 and the restoring force RF. In an exemplary embodiment, if the threshold start-up pressure is about 2 bars the counteracting force CF is pre-set at about 1 .8 bars. Thus, during the normal working status of the pumping device 100 the actuation element 130 is configured to be moved to the inoperative position by the hydrostatic fluid pressure in the pressure chamber 110 acting on the actuation element 130. The hydrostatic fluid pressure in the pressure chamber 110 may act against the spring force of the positioning means 132. This also releases the counteracting force CF acting on the closing member 126 of the non-return valve 124. Further, during the normal working status of the pumping device 100, as the hydrostatic fluid pressure in the pressure chamber 110 and the discharge line 120 is substantially equal, the uninterrupted fluid flow through the non-return valve 124 is sufficient to retain the closing member 126 in the open position and the pressurized fluid is delivered at the fluid release control valve 106.

According to an embodiment of the present invention, the pumping device 100 may include a sensor unit 134. The sensor unit 134 may include a flow sensor and a pressure sensor which are configured to monitor a fluid flow rate and the hydrostatic fluid pressure in the discharge line 120, respectively. The flow sensor may embody a Hall-Effect sensor or an optical sensor, while the pressure sensor may embody a piezoelectric sensor, a strain gauge sensor or a bistable mechanical pressure switch. However, various other types of sensors and measurement units may be used in the sensing unit 134 without limiting the scope of the present invention. The sensor unit 134 may be operatively connected to a programmable controller 136 (e.g. an Electronic Control Unit) configured to control an operation of the pumping device 100. The controller 136 may include a processor operably associated with other electronic components such as, a storage device or memory, a sensor interface, a control signal interface and/or various communication channels for receiving and transmitting signals. The controller 136 is configured to receive a voltage or current signal indicative of the fluid flow rate and the hydrostatic fluid pressure in the discharge line 120 from the sensor unit 134. Based on the received signal by the controller 136, the memory may be operable on the processor to compare the fluid flow rate and the hydrostatic fluid pressure in the discharge line 120 with a threshold fluid flow rate and the threshold start-up pressure and subsequently transmit control signals to control the operation of the pumping device 100. In an embodiment, the threshold fluid flow rate and the threshold start-up pressure may be a predetermined based on the design and application of the pumping device 100 and stored in the memory of the controller 136.

According to an aspect of the present invention, when the operator shuts the fluid release control valve 106 or a certain obstruction is observed in the discharge line 120 such that the fluid flow rate decreases and reaches the threshold fluid flow rate or the fluid flow ceases in the discharge line 120 and the closing member 126 may move towards the closed position, the controller 136 stops or switches off the operation of the pumping device 100 based on the control signal received from the flow sensor of the sensor unit 134. Thus, the hydrostatic fluid pressure in the pressure chamber 110 rapidly decreases. In this situation, the restoring force RF and the hydrostatic fluid pressure in the discharge line 120 acts on the closing member 126 such that the combined force due to the restoring force RF and the hydrostatic fluid pressure acting on the closing member 126 is more than the counteracting force CF exerted by the positioning means 132. Thus, the actuation element 130 cannot move to the operative position to open the non-return valve 124, and the nonreturn valve 124 automatically prevents the backflow of the fluid in the pressure chamber 110 and/or the suction line 118. Moreover, after switching off the pumping device 100 the hydrostatic fluid pressure in the discharge line 120 acts as additional forces onto the closing member 126.

Following this, if the operator opens the the fluid release control valve 106 or remove the obstruction in the discharge line 120 such that the hydrostatic fluid pressure in the discharge line 120 decreases and reaches the threshold start-up pressure, the controller 136 starts the operation of the pumping device 100 based on the control signal received from the pressure sensor of the sensor unit 134. Thus, the hydrostatic fluid pressure in the pressure chamber 110 gradually increases and the non-return valve 124 opens by moving the closing member 126 to the open position. Once again, when the pumping device 100 may reach the normal state of working and the actuation element 1 30 is moved to the inoperative position by the fluid pressure acting on the actuation element 130. As illustrated in FIG. 1 , the flow control systems 122 are disposed on the discharge line 120 of the pumping device 100. However in various other embodiments, a pumping device may be embodied as a pump apparatus such that a flow control system may be arranged in a pump housing of the pump apparatus. FIG. 2 illustrates a perspective view of a pumping device embodied as a pump apparatus 200, according to an embodiment of the present invention. The pump apparatus 200 may be an electric pressure pump. In various other embodiments, the pump apparatus 200 may be include other pump assemblies, such as submersible pumps, garden pumps, fountain pumps, pressure tank units or the like.

The pump apparatus 200 includes a pump housing 202 made of an impact-resistant plastic or metal, such as stainless steel. The pump housing 202 defines a pressure chamber 204. The pressure chamber 204 may house an electric motor driven impeller (not shown) disposed on a pump shaft, which also may be air-cooled. The pump apparatus 200 includes at least one inlet 206 arranged in fluid communication with the pressure chamber 204 for the intake of the fluid. The inlet 206 is provided with an externally threaded inlet connection port 208 to connect with a suction line via a hose connector and/or via a pre-filter. Further, a replaceable pump filter unit 210 is provided with the inlet 206 to define a filling port 212 through which, for example, the fluid into the pressure chamber 204 can be filled. The filling port 212 is generally closed a sealing cap 214.

Further, the pump apparatus 200 may include a handle 226 connected to the pump housing 202 and can be used for carrying the pump apparatus 200 around. Moreover, the pump apparatus 200 may include a drainage port along with a drain screw 229 to empty the pump apparatus 200 during storage, transportation or a maintenance operation.

The pump apparatus 200 further includes an outlet 216. In the illustrated embodiment, the outlet 216 may include an outlet connection port 222. In an embodiment, the outlet connection port 222 may be swivelling type to further customize the connection according to the operator's individual requirements. Alternatively, when not in use the outlet connection port 222 may be closed by a sealing cap. It will be apparent to a person having ordinary skill in the art that, a discharge line or hose may be connected to the outlet connection port 222 via a hose connector. The outlet 216 is also arranged in fluid communication with the pressure chamber 204 via a pressure fluid line (not shown).

According to an embodiment of the present invention, a flow control system 220 may be disposed on the pressure fluid line disposed between the pressure chamber 204 and the outlet 216. The flow control system 220 is configured to separate the pressure chamber 204 from the the outlet 216 while the the outlet 216 is closed and/or an obstruction is present in the the outlet 216. Thus, the flow control system 220 prevents the fluid from draining back from the pump apparatus 200 into the suction line or supply hose. Additionally, the flow control system 220 may be used to supply the fluid at a pre-set pressure. As illustrated in FIG. 2, a covering member for the flow control system 220 is removed to show the details of the flow control system 220. Moreover, FIGS. 3A, 3B, and 3C illustrate a partial sectional view of the pump apparatus 200 about AA' to show an internal structure of the flow control system 220.

Referring to FIG. 3A, the flow control system 220 includes a nonreturn valve 230 that allows an unidirectional flow of the fluid from the pressure chamber 204 towards the outlet 216 and configured to block the fluid flow from the discharge line 120 due to the fact that a hydrostatic fluid pressure in the pressure chamber 204 drops below a hydrostatic fluid pressure in the outlet 216 due to the switch of off the pump apparatus 200 mainly due an obstruction observed in the outlet 216. Thus, prevents a backflow of the fluid into the pressure chamber 204 and/or the inlet 206. In an embodiment, the non-return valve 230 may be a check valve having a closing member, such as a valve body 232 which is movable with respect to a valve seat 238 to open or closed the non-return valve 230. In an open position of the non-return valve 230 (as shown in FIG. 3A), the valve body 232 is moved away from the valve seat 238 to allow an uninterrupted fluid flow through the non-return valve 230. In a closed position of the non-return valve 230, the valve body 232 is moved towards the valve seat 238 to create a seal and block the fluid flow through the non-return valve 230. The non-return valve 230 may also include a valve spring 234 to exert a restoring force on the valve body 232 and sealingly press the valve body 232 against the valve seat 238. The non-return valve 230 may further include a sealing member 236, such as an O-ring valve seal attached to the valve body 232 and configured to abut against the valve seat 238 in the closed position of the non-return valve 230. It will be apparent to a person having ordinary skill in the art the valve seat 238 may be integrally formed with the pump housing 202.

According to an embodiment of the present invention, the flow control system 220 includes an actuation mechanism 242 having an actuation element 244. The actuation element 244 is disposed along a substantially lateral direction with respect to a movement of the valve body 232 and is movable between an operative position (as shown in FIG. 3A) and an inoperative position with respect to the valve body 232. In the operative position, the actuation element 244 may apply the counteracting force to move the valve body 232 away from the valve seat 238 towards the open position. The counteracting force acting on the valve body 232 acts against the restoring force exerted by the valve spring 234 on the valve body 232. In the inoperative position of the actuation element 244, the counteracting force acting on the valve body 232 is released. Thus, while the actuation element 244 is in the inoperative position and while the hydrostatic fluid pressure in the pressure chamber 204 equals the hydrostatic fluid pressure in the outlet 216, the valve body 232 can move towards the valve seat 238 under the action of the restoring force RF. In the illustrated embodiment, the actuation element 244 is embodied as control pin having a substantially wedge shaped or conical engagement portion 248 which is configured to contact with a cam surface 240 of the valve body 232 and forcibly push the valve body 232 and the sealing member 236 away from the valve seat 238. According to an aspect of the present invention the actuation element 244 is constantly biased towards the operative position by a positioning spring 246. In an aspect of the present invention, the spring force exerted by the positioning spring 246 is greater than the restoring force exerted by the valve spring 234. However, during a normal working status of the pump apparatus 200 the hydrostatic fluid pressure, equal to or above the threshold start-up pressure, may be present in the pressure chamber 204 and the outlet 216. Further, to achieve a leak-proof sealing in the pump housing 202 during the movement of the actuation element 244 one or more sealing members 250, such as O-rings are provided.

During the starting-up of the pump apparatus 200, generally after a new installation or after performing a maintenance operation, while the actuation element 244 is in the operative position and the valve body 232 is forcibly moved away from the valve seat 238 towards the open position, any air already present in the pump apparatus 200 can flow out and an inflow of the fluid into the pump apparatus 200 is facilitated.

Further, the counteracting force exerted by the positioning spring 246 is pre-set at slightly less combined force of threshold start-up pressure in the pump apparatus 200 and the restoring force RF. Thus, during the normal working status of the pump apparatus 200 the actuation element 244 is configured to be moved to the inoperative position by the hydrostatic fluid pressure in the pressure chamber 204. The hydrostatic fluid pressure in the pressure chamber 204 may act against the spring force of the positioning spring 246 and releases the counteracting force acting on the valve body 232 of the non-return valve 230. Further, as illustrated in FIG. 3B, during the normal working status of the pump apparatus 200, as the hydrostatic fluid pressure in the pressure chamber 204 and the outlet 216 is substantially equal, the uninterrupted fluid flow through the non-return valve 230 is sufficient to retain the valve body 232 in the open position and the pressurized fluid is delivered at the outlet 216.

According to an embodiment of the present invention, the pump apparatus 200 includes a flow sensor comprising of a magnetic element 254 and a Hall-effect sensor/transducer 256. The magnetic element 254 is attached to the valve body 232 and configured to generate a dynamic magnetic field in response to a movement of the valve body 232 between the open position and the closed position of the non-return valve 230. The Hall-effect sensor 256 is fixedly mounted on outer wall of the nonreturn valve 230. The Hall-effect sensor 256 is configured to outputting a voltage or a current signal based on a position of the magnetic element 254 from the Hall-effect sensor 256. Further, the Hall-effect sensor 256 may be calibrated against the magnetic field strength corresponding to the open and the closed position of the non-return valve 230 and and monitor a fluid flow rate through the non-return valve 230. The pump apparatus 200 may further include a pressure sensor 252, such as a piezoelectric sensor, a strain gauge sensor or a bistable mechanical pressure switch which is configured to monitor the hydrostatic fluid pressure in the outlet 216. The Hall-effect sensor 256 and the pressure sensor 252 may be operatively connected to a programmable controller (not shown) which is configured to control an operation of the pump apparatus 200. The controller is configured to receive a voltage or current signal indicative of the fluid flow rate through the non-return valve 230 and the hydrostatic fluid pressure in the outlet 216 from the Hall-effect sensor 256 and the pressure sensor 252, respectively. Based on the received signal by the controller may transmit control signals to control the operation of the pump apparatus 200.

Referring to FIG. 3C, according to an aspect of the present invention, when the operator shuts the outlet 216 such that the fluid flow rate through the non-return valve 230 decreases and the fluid flow ceases and the valve body 232 moves towards the closed position. The controller stops the operation of the pump apparatus 200 based on the control signal received from the Hall-effect sensor 256. Thus, the hydrostatic fluid pressure in the pressure chamber 204 rapidly decreases. In this situation, the restoring force and the hydrostatic fluid pressure in the outlet 216 act on the valve body 232 such that the combined force due to the restoring force from the valve spring 234 and the hydrostatic fluid pressure acting on the valve body 232 is more than the counteracting force exerted by the positioning spring 246. Thus, the actuation element 244 cannot move to the operative position to open the non-return valve 230 and the non-return valve 230 automatically prevents the backflow of the fluid in the pressure chamber 204 and/or the suction line.

Following this, if the operator opens the the outlet 216 such that the hydrostatic fluid pressure in the outlet 216 decreases and reaches the threshold start-up pressure, the controller starts the operation of the pump apparatus 200, based on the control signal received from the pressure sensor 252. Thus, the hydrostatic fluid pressure in the pressure chamber 204 gradually increases and the non-return valve 230 opens by moving the valve body 232 to the open position. The actuation element 244 is moved to the inoperative position by the fluid pressure acting on the actuation element 244.

In an alternative embodiment, the actuation mechanism/actuation element may be embodied as a biasing member, such as a compression spring or tension spring, disposed within the pump housing 302 and arranged in a direction which is in-line with the movement of the valve body 332 and configured to constantly bias the valve body 332 in the open position.

In the drawings and specification, there have been disclosed preferred embodiments and examples of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation of the scope of the invention being set forth in the following claims.

PART LIST

100 pumping device

102 pump

104 fluid reservoir

106 fluid release control valve

108 pump housing

1 1 0 pressure chamber

1 1 2 electric motor

1 14 inlet

1 1 6 outlet

1 1 8 suction line

120 discharge line

122 flow control system

124 non-return valve

126 closing member

127 valve seat

128 actuation mechanism

129 valve spring

130 actuation element

132 positioning means

134 sensor unit

136 controller

RF restoring force

CF counteracting force

200 pump apparatus

202 pump housing

204 pressure chamber

205 motor chamber

206 inlet

208 inlet connection port

21 0 pump filter unit 21 2 filling port

214 sealing cap

21 6 outlet

220 flow control system

222 outlet connection port

224 second sealing cap

226 handle

229 drain screw

230 non-return valve

232 valve body

234 valve spring

236 sealing member

238 valve seat

240 cam surface of valve body

242 actuation mechanism

244 actuation element

246 positioning spring

248 engagement portion of actuation element

250 sealing members

252 pressure sensor

254 magnetic element

256 Hall-effect sensor