BACKGROUND [0001] The present invention relates generally to equipment used in fuel dispensing environments. More specifically, embodiments of the present invention relate to a fuel dispenser having a power supply protection arrangement.

[0002] Fuel dispensers may be subject to variations in AC power supply connectivity and/or quality. Additionally, fuel dispensers may suffer from component failures, due to such events as power glitches, power surges, lightning strike, electrostatic discharge (ESD), or the like. In some fueling environments, such as rural areas or areas with a developing power grid, power supply failures and transients may cause one or more fuel dispensers to fail. This results in a loss of revenue to the fueling station operator. In areas where there are few qualified technicians to repair the dispenser, the loss of revenue is more acute.

SUMMARY

[0003] The present invention recognizes and addresses various considerations of prior art constructions and methods. According to one aspect, the present invention provides a fuel dispenser including a fuel nozzle configured to be connected to a vehicle fuel system, fuel piping configured to transfer fuel from a fuel storage tank associated with the fuel dispenser through the fuel nozzle into the vehicle fuel system, as well as fuel handling components operative to control and measure flow of the fuel through the fuel piping. The fuel dispenser further includes a suitable power supply such as a switch mode power supply configured to receive alternating current power from a mains power source and provide direct current power for one or more direct current components associated with the fuel dispenser. A power supply protection arrangement configured to limit voltage in excess of a predetermined voltage threshold from reaching the power supply is also provided.

[0004] Those skilled in the art will appreciate the scope of the present invention and realize additional aspects thereof after reading the following detailed description of preferred embodiments in association with the accompanying drawing figures. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] A full and enabling disclosure of the present invention, including the best mode thereof directed to one skilled in the art, is set forth in the specification, which makes reference to the appended drawings, in which:

[0006] FIG. 1 illustrates a perspective view of an exemplary fuel dispenser in accordance with an embodiment of the present invention. [0007] FIG. 2 illustrates a diagrammatic representation of internal components of the fuel dispenser of FIG. 1 according to an embodiment of the present invention.

[0008] FIG. 3 illustrates a block diagram of an example of a fuel dispenser power supply and associated protection arrangement according to an embodiment of the present invention.

[0009] FIG. 4 illustrates a block diagram of one example of a power supply protection arrangement according to an embodiment of the present invention.

[0010] FIGs. 5A and 5B show operation of the circuit of FIG. 4 in normal and overvoltage conditions, respectively.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0011] Reference will now be made in detail to presently preferred embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope or spirit thereof. For instance, features illustrated or described as part of one embodiment may be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the present disclosure including the appended claims and their equivalents.

[0012] A fuel dispenser according to the present invention may include a power supply protection arrangement configured to prevent or limit excessive voltage from reaching a power supply, which may otherwise cause damage to or malfunction of the power supply. The power supply protection arrangement may be configured to monitor supplied AC voltage and interrupt the voltage source in response to the voltage exceeding a predetermined voltage threshold. In some example embodiments, the power supply protection arrangement may include a switch, which may be opened in response to the excessive voltage and closed in response to the voltage returning to a suitable value. In an example embodiment, the power supply protection arrangement may also include one or more energy storage components, such as at least one suitable capacitor to supply power during the interruption of the external power source.

[0013] In some example embodiments, the power supply protection circuit may also include one or more surge suppression components configured to shunt, clamp, or otherwise dissipate undesired electrical transients, such as voltage spike of about 0.5 kV to about 4 kV. The surge suppression components may include, for example, one or more of a metal-oxide varistor (MOV), a gas discharge tube (GDT) and a thyristor surge protector device (TSPD).

[0014] Some embodiments of the present invention may be particularly suitable for use with a fuel dispenser in a retail service station environment, and the below discussion will describe some preferred embodiments in that context. However, those of skill in the art will understand that the present invention is not so limited. In fact, it is contemplated that embodiments of the present invention may be used with any fluid dispensing environment and with other fluid dispensers. For example, embodiments of the present invention may also be used with diesel exhaust fluid (DEF) dispensers, compressed natural gas (CNG) dispensers, and liquefied petroleum gas (LPG) and liquid natural gas (LNG) applications, among others.

Example Fuel Dispenser

[0015] FIG. 1 is a perspective view of an exemplary fuel dispenser 10 according to an embodiment of the present invention. Fuel dispenser 10 includes a housing 12 with a flexible fuel hose 14 extending therefrom. Fuel hose 14 terminates in a fuel nozzle 16 adapted to be inserted into a fill neck of a vehicle's fuel tank. Fuel nozzle 16 includes a manually-operated fuel valve. Various fuel handling components, such as valves and meters, are also located inside of housing 12. These fuel handling components allow fuel to be received from underground piping and delivered through fuel hose 14 and fuel nozzle 16 to a vehicle's fuel system (fuel tank).

[0016] Fuel dispenser 10 has a customer interface 18. Customer interface 18 may include an information display 20 relating to an ongoing fueling transaction that shows the amount of fuel dispensed and the price of the dispensed fuel. Further, customer interface 18 may include a display 22 that provides instructions to the customer regarding the fueling transaction. Display 22 may also provide advertising, merchandising, and multimedia presentations to a customer, and may allow the customer to purchase goods and services other than fuel at the dispenser.

[0017] FIG. 2 is a schematic illustration of internal fuel flow components of fuel dispenser 10 according to an embodiment of the present invention. In general, fuel may travel from an underground storage tank (UST) via main fuel piping 24 to fuel dispenser 10 and nozzle 16 for delivery. In some embodiments, fuel dispenser 10 may have an internal pumping unit to draw fuel from the UST. In other cases, a submersible turbine pump (STP) associated with the UST may be used to push fuel to the fuel dispenser 10.

[0018] In this case, main fuel piping 24 passes into housing 12 through a shear valve 26. As is well known, shear valve 26 is designed to close the fuel flow path in the event of an impact to fuel dispenser 10. Shear valve 26 contains an internal fuel flow path to carry fuel from main fuel piping 24 to internal fuel piping 28.

[0019] Fuel from the shear valve 26 flows toward a flow control valve 30 positioned upstream of a flow meter 32. Alternatively, valve 30 may be positioned downstream of the flow meter 32. In one embodiment, valve 30 may be a suitable proportional solenoid controlled valve.

[0020] Flow control valve 30 is under control of a control system 34. In this manner, control system 34 can control the opening and closing of flow control valve 30 to either allow fuel to flow or not flow through meter 32 and on to the hose 14 and nozzle 16. Control system 34 may comprise any suitable electronics with associated memory and software programs running thereon whether referred to as a processor, microprocessor, controller, microcontroller, or the like. In a preferred embodiment, control system 34 typically includes a pump control node (PCN) and a "card reader in dispenser" (CRIND) module. The PCN includes the hardware and software necessary to control the dispenser's hydraulic functions. The CRIND module includes the hardware and software necessary to support any payment processing and peripheral interfaces, such as PIN pad, card reader, and the displays(s). The CRIND module may, for example, inform the PCN that a transaction has been authorized, which in turn causes valve 30 to open. In addition, control system 34 may be in electronic communication with a site controller located at the fueling site. The site controller, which may take the form of or be incorporated into a point-of-sale (POS) system, communicates with control system 34 to control authorization of fueling transactions and other conventional activities.

[0021] A vapor barrier 36 delimits hydraulics compartment 38 of fuel dispenser 10, and control system 34 is located in electronics compartment 40 above vapor barrier 36. Fluid handling components, such as flow meter 32, are located in hydraulics compartment 38. In this regard, flow meter 32 may be any suitable flow meter known to those of skill in the art, including positive displacement, inferential, and Coriolis mass flow meters, among others. Meter 32 typically comprises electronics 42 that communicates information representative of the flow rate or volume to control system 34. For example, electronics 42 may typically include a pulser as known to those skilled in the art. In this manner, control system 34 can update the total liters (or gallons) dispensed and the price of the dispensed fuel on information display 20.

[0022] As fuel leaves flow meter 32 it enters a flow switch 44, which preferably comprises a one-way check valve that prevents rearward flow through fuel dispenser 10. Flow switch 44 provides a flow switch communication signal to control system 34 when fuel is flowing through flow meter 32. The flow switch communication signal indicates to control system 34 that fuel is actually flowing in the fuel delivery path and that subsequent signals from flow meter 32 are due to actual fuel flow. Fuel exits flow switch 44 through internal fuel piping 46 to fuel hose 14 and nozzle 16 for delivery to the customer's vehicle.

[0023] A blend manifold may also be provided downstream of flow switch 44. The blend manifold receives fuels of varying octane levels from the various USTs and ensures that fuel of the octane level selected by the customer is delivered. In addition, fuel dispenser 10 may comprise a vapor recovery system to recover fuel vapors through nozzle 16 and hose 14 to return to the UST.

[0024] The various peripherals and other components of fuel dispenser 10 may require AC and/or DC voltage of different voltage levels for their operation. Toward this end, fuel dispenser 10 includes a power distribution system 100 in accordance with the present invention. Power distribution system 100 preferably receives AC mains power at a known nominal level and provides both AC and DC power to the various components inside the dispenser. For example, the AC power needed by some of the internal components may be at the same or a different voltage level than the input voltage. In addition, the DC voltage can be supplied by a suitable power supply, such as a switch mode power supply (SMPS) 102, at a particular voltage level equal to or slightly higher than the level required for the various DC-powered components. Generally, the SMPS can take AC or DC input and generates a DC output. Each such DC-powered component may have an associated voltage regulator to provide the precise DC voltage level that it requires. Preferably, the AC power may be provided through a power supply protection circuit 200 configured to prevent an overvoltage condition at power supply 102.

[0025] Referring now also to FIG. 3, power supply 102 receives AC power from an external AC power source 104, such as a mains supply associated with the gas station or other fueling environment. The AC power source 104 may typically supply voltage at a level within the range of 98-240 VAC depending on the local available voltage. The switch mode power supply may convert the AC power to DC power, such as 24 VDC for supplying DC-powered components within the dispenser, such as flow control valves, pump control signals, various other hydraulic components of the fuel dispenser, thermal printers, or the like.

Example Power Distribution System

[0026] As shown in FIG. 3, a fuel dispenser power distribution system 100 includes the switch mode power supply (SMPS) 102 and power supply protection arrangement 200. The power supply protection circuit 200 may be electrically connected in series between the external AC power source 104 and the power supply 102. As noted above, the power supply protection circuit 200 may receive AC power between 98 VAC and 240 VAC based on the local available voltage. The power supply protection circuit 200 may be configured to limit or prevent voltage in excess of a predetermined voltage threshold from reaching the power supply 102. In addition, as will be explained, power supply protection arrangement 200 may continue to provide an adequate voltage (for a period of time) in an under-voltage condition, such as less than 80 VAC, to allow uninterrupted operation of the fuel dispenser. The power supply protection circuit 200 may also be configured to suppress a potentially damaging voltage surge, e.g., a voltage of between 0.5kV to 4.0 kV, appearing on the power supply line.

[0027] FIG. 4 illustrates a block diagram of exemplary circuitry which may comprise a power supply protection arrangement 200 in accordance with the present invention. As noted, power supply protection arrangement 200 may nominally receive alternating current power between 98 VAC and 240 VAC from external AC power source 104. Power supply protection arrangement 200 may include surge suppression components (labeled "surge suppressor 202") configured to prevent voltage spikes from reaching the power supply 102 and/or other downstream components. Surge suppressor 202 is operative to shunt, clamp, or otherwise dissipate large voltage transients, such as voltage spike, of about 0.500 kV to about 4 kV. By way of example, surge suppressor 202 may comprise a metal-oxide varistor (MOV), a thyristor surge protection device (TSPD), a gad discharge tube (GTD), or the like. Due to this fault current generated, the safety FUSE (which is mounted outside of this circuit) shall blow to avoid a fire hazard. But now this fault current will be generated only in case of very high energy spikes and not for the faulty overvoltage situation such as above 300 VAC.

[0028] In some example embodiments, surge suppressor 202 may degrade over its lifetime. The degradation of the surge suppressor 202 may be accelerated in response to exposure to large voltage spikes or transients. A fuse, such as a thermal fuse, may be electrically connected in series with the surge suppressor. In an instance in which degradation of the surge suppressor 202 causes an increase of current through the surge suppressor 202, the fuse 203 may open preventing excessive current or electrical shorts. [0029] Other components of power supply protection arrangement 200 may include a voltage sensor 204, charge controller 206, switch 208, and energy storage component 210. Power supply switch 208 is configured to interrupt the incoming AC power when it exceeds a predetermined voltage threshold, such as a voltage exceeding 290 VAC. In this regard, it will be appreciated that the threshold voltage will generally depend on the particular characteristics of power supply 102. Such power supplies can generally tolerate some excessive voltage for short periods of time without damage. For example, a typical power supply that delivers 24 VDC up to 72 Watts may be able to withstand 300 VAC input for a maximum of 5 seconds and 2kV surge of 12 μ 8 duration for up to approximately 50 times. Power supply switch 208 may comprise a mechanical switch or an electronic switch, such as a silicon controlled rectifier (SCR), transistor, or the like. In some instances, power supply switch 208 may be configured to quickly open before damage occurs to the switch mode power supply 102, such as before 1 microsecond, after sensing AC power in excess of the predetermined voltage threshold.

[0030] Voltage sensor 204 is configured to sense or measure the voltage of the AC power supplied by the external AC power source 104. Voltage sensor 204 acts fast to trigger activation of charge controller 206. Charge controller 206 may open the power supply switch 208, such as by applying or removing a gating bias, which may cause the switch 208 to interrupt the AC power supplied to the switch mode power supply 102.

[0031] In some embodiments, charge controller 206 may cause the power supply switch 208 to close in response to the AC power returning to a value less than the predetermined voltage threshold. Charge controller 206 may cause a gate bias to be applied or removed to close the power supply switch 208.

[0032] In an example embodiment, the power supply protection arrangement 200 may also include one or more energy storage components 210, such as one or more capacitors. The AC power may be utilized to charge the components 210 during normal operations. In response to the AC power dropping to less than a storage voltage, e.g. normal AC power voltage, due to a transient or switch 208 opening, components 210 may provide power to the switch mode power supply 102. In this regard, charge controller 206 provides controlling action which keeps charging the energy storage component(s) so as to supply the AC/DC power adequately so that the power supply can generate the rated output.

[0033] Referring now to FIG. 5A, in normal operation the switch is always "ON" and the charge controller is disabled. The output capacitor is fully charged and delivers a constant DC voltage to the SMPS input. Referring now to FIG. 5B, if there is sustained overvoltage beyond threshold, the switch is controlled by the charge controller so as to maintain a predefined charge in the output capacitor enough to sustain the SMPS output load. The charge controller is triggered by the over voltage detector. During a very high voltage surge, the surge suppression device such as a MOV which is rated well above the threshold voltage of overvoltage detection stage, conducts to create an additional current path so that a fault current is generated which can blow a FUSE connected via an external circuit. In normal operating voltage range the surge suppression device does not conduct.

[0034] Many modifications and other embodiments of the invention set forth herein will come to mind to one skilled in the art to which the invention pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the embodiments of the invention are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the invention. Moreover, although the foregoing descriptions and the associated drawings describe example embodiments in the context of certain example combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative embodiments without departing from the scope of the invention. In this regard, for example, different combinations of elements and/or functions than those explicitly described above are also contemplated within the scope of the invention. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.