NZ224188A - Liquefied gas dispenser controlled by pressure responsive control valve - Google Patents

Description

Q n NEW ZEALAND PATENTS ACT 1953 COMPLETE.SPECIFICATION LIQUEFIED' GAS DISPENSER SYSTEM WE, GAS CYLINDER SERVICES PTY. LIMITED, a company incorporated under the laws of the State of Victoria, Commonwealth of Australia, of 50 Norcal Road, Nunawading, Victoria, 3131, Australia, hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the fo1lowing statement:- la.

This invention relates to liquefied gas dispensing systems, particularly for dispensing LPG or other liquefied gas in filling vehicle fuel tanks, although the invention is not limited to this particular field.

LPG dispenser systems are known which include a vapour remover which receives liquefied gas from a supply tank and pump associated with the tank. The vapour remover is for separating gas phase from liquid phase and returning the separated gas phase to the tank. A supply line extends from the vapour remover to a i filling coupling for connection to aj vehicle fuel tank for receiving liquefied gas. Metering means is located downstream of the vapour remover and is operative to measure the amount of liquefied gas dispensed during the dispensing operation and to calculate a charge for the gas. A dispensing control valve is provided for controlling the flow of liquefied gas in the supply line between the metering means and the filling coupling.

In the known LPG dispenser systems, the dispensing control valve is solenoid operated. The solenoid valve holds the supply line to the filling coupling open during an initial time period to enable vapour in the supply line to be pressurised or purged so that principally liquid phase fills the line to the filling coupling. Then the solenoid valve is caused to close the supply line during which stage the metering means is reset to zero. Finally the solenoid valve is operated to reopen the supply line to enable a metered dispensing operation to commence. The operation of the solenoid valve is under timer control.

The known solenoid valves are prone to leakage of gas through the valve. This feature, together with the use of a timer operated control valve can enable incorrect metering and can also enable customer manipulation of the system to enable significant amounts of liquefied gas to be dispensed without being properly recorded by the metering means.

Also with the present dispenser systems for vehicles, if two dispensing lines are to be provided at a single bowser, the two dispensing systems have in the past both been provided with respective vapour, removers and all components downstream of the v vapour removers. j It is an object of the first aspect of the present invention to provide a liquefied gas dispenser system which can be more accurate and less susceptible to manipulation than the prior systems outlined above.

It is an object of the second aspect of the present invention to provide a liquefied gas dispensing system which enables simultaneous dispensing of liquefied gas to two destinations without unnecessary duplication of system components.

According to a first aspect of the present invention there is provided a liquefied gas dispenser system including: a vapour remover for receiving liquefied gas from a supply and a pump associated with the supply and for separating gas phase from liquid phase; a supply line extending from the vapour remover to a filling coupling for connection to a destination for liquefied gas; metering means downstream of the vapour remover and operative to measure the amount of liquefied gas dispensed during a dispensing operation; and a dispensing control valve for controlling the flow of liquefied gas in the supply line between o 224188 3. the metering means and the filling coupling, the control valve having an inlet port for receiving liquefied gas and an outlet port for the liquefied gas to be conveyed to the filling coupling, the control valve being operable to open the supply line if liquefied gas is pressurised up stream thereof, whereby liquefied gas dispensing flow can occur only if the liquefied gas is pressurised and whereby a significant liquefied gas pressure ^ drop upstream of the control valve will result in closing of the supply-line.

The control valve in the preferred embodiment is a pilot operable control valve in selective communication via a pilot line with a source of pressurised pilot fluid the pilot operable control valve being operable in response to the selective application of pilot fluid pressure in the pilot line to open the pilot operable control valve to allow liquefied gas flow from the inlet port to the outlet port of the pilot operable control valve. The pilot line is selectively communicable with pressurised liquefied gas upstream of the pilot operable control valve, e.g. with the pressurised liquified gas in the vapour remover.

In the preferred embodiment a selectively operable pilot control valve is included for controlling application of pilot fluid pressure in the pilot line, the pilot control valve including a pilot outlet connected by the pilot line to the pilot line port of the pilot operable control valve, a low pressure inlet connected in use to a source of relatively low pressure liquefied gas, and a - high pressure inlet connected in use to receive the pressurised liquefied gas from upstreany^Qr theP^ pilot k ol | 14 MAR 1990li <yj *»». ^ ;4. ;22 4 1 8 ;operable control valve; the pilot control valve being selectively operable to connect either the low pressure inlet to the pilot outlet or the high pressure inlet to the pilot outlet. The system preferably includes a vapour return line from the vapour remover to the liquefied gas supply, the low pressure inlet of the pilot control valve being connected in use to the vapour return line or to the liquefied gas supply upstream of the associated pump. ;Preferably there is a normal fail safe condition of the pilot control valve which comprises connectipn of the low pressure ;\ ;inlet to the pilot outlet. | ;The pilot control valve may be electrically operable to switch between two conditions corresponding respectively to connection of the low pressure inlet to the pilot outlet and a connection of the high pressure inlet to the pilot outlet. ;The dispenser system preferably further includes an ope ration control circuit for causing the dispensing control valve to open the supply line for a short time interval following start-up of the supply pump and before dispensing through the filling coupling commences so as to thereby allow pressurisation or purging of vapour in the supply line, then to cause the dispensing control valve to close for a period during which the metering means is reset, then subsequently to cause the dispensing control valve to reopen for enabling dispensing of liquefied gas through the supply line and filling coupling. ;According to a second aspect of the present invention there is provided a liquefied gas dispenser system including: a vapour remover for receiving liquefied gas from a supply and a pump associated with the supply and for separating gas phase from ;o ;1 0 ;liquid phase; a supply line extending from the vapour remover to a filling coupling for connection to a destination for liquefied gas; metering means downstream of the vapour remover and operative to measure the amount of liquefied gas dispensed therethrough during a dispensing operation; a dispensing control valve for controlling the flow of liquefied gas in the supply line between the metering means and the filling coupling, the control valve having an inlet port for receiving liquefied gas and an outlet port for the liquefied gas to be conveyed to the filling coupling; and a supply junction between the vapour remover and the metering means, the supply junction including an inlet and at least two outlets in communication with the inlet, a first one of the outlets being connected to the supply line, and a second outlet being connected to a second supply line, 15 extending from the vapour remover to a second filling coupling for connection to a destination for liquefied gas; a second _ metering means downstream of the vapour remover and operative to measure the amount of liquefied gas dispensed therethrough during a dispensing operation, a second dispensing control valve for controlling the flow of liquefied gas in the second supply line ">>) between the second metering means and the second filling coupling, the second control valve having an inlet port for receiving liquefied gas and an outlet port for the liquefied gas to be conveyed to the second f.illing coupling, whereby a single 25 common vapour remover is used for supplying liquefied gas to at least two supply lines and associated filling couplings for enabling two simultaneous dispensing operations to be carried out. ;20 ;The vapour remover preferably includes a liquid tank in which vapour phase is separated from liquid phase, the inlet of the. supply junction being in fluid communication with the bottom of the liquid tank. ;The inlet of the supply junction preferably is closely connected to the bottom of the liquid tank and there are provided two outlets of the supply junction which are closely adjacent the respective metering means receiving liquefied gas from the two outlets whereby there is minimal distance for liquefied gas flow from the vapour remover to either' of the two metering means. ;Possible and preferred features ! of the present invention will now be described with particular reference to the accompanying drawings. However it is to be understood that the features illustrated in and described with reference to the drawings are not to be construed as limiting on the scope of the invention. In the drawings: ;Fig. 1 is the schematic view of a liquefied gas dispenser system according to a possible and preferred embodiment of the present invention. ;In the drawing the system includes a vapour remover 10 which receives liquefied gas through line 11 from a supply tank (not shown) and an associated pump (not shown). The liquefied gas is pressurised by the pump. The vapour remover comprises a tank in which gas phase can separate from the liquid phase, the gas phase being returned through the vapour return line 12 to the supply tank. The line 12 is provided with a check valve 13 and double check 14 as is known in the art. ;Supply line 15 extends from the vapour remover 10 to a filling coupling 16, e.g. of the kind for connection to a vehicle liquefied gas fuel tank. Also provided in the supply line 15 is metering means 17 downstream of the vapour remover 10 and operative to measure the amount of liquefied gas dispensed during a dispensing operation. The metering means may be of conventional type having a measuring chamber which has a rotary element on a shaft, the rotation of the shaft being used by the system electronics to calculate the total amount of liquid dispensed and the cost of that dispensed gas. ;Downstream of the metering means li7 is a dispensing control valve 20 for controlling the flow liquefied gas in the supply line 15 between the metering means 17 and the filling coupling 16. The control valve 20 has an inlet port 21 receiving liquefied gas from the metering means 17 and an outlet port 22 for liquefied gas to be conveyed e.g. via conventional I.S.C. valve 23, sight gauge 24 and line break coupling 25 to the coupling 16. ;The control valve 20 is operable to open the supply line 15 if liquefied gas is pressurised upstream thereof, whereby liquefied gas dispensing flow can occur only if the liquefied gas is pressurised and whereby a significant liquefied gas pressure drop upstream of the control valve 20 will result in closing of the supply line 15. ;In the drawing the control valve 20 is a pilot operable control. v„alve, or differential valve, having a pilot line port 30 in selective communication via a pilot line 31 with a source of pressurised pilot fluid. The control valve 20 is operable in response to selective application of pilot fluid pressure in the ;8. ;CL * S pilot line 31 to open the control valve 20 to allow liquefied gas flow from the inlet port 21 to the outlet port 22. The pilot line 31 is selectively communicable with the pressurised liquefied gas in the vapour remover 10. This is achieved by providing selectively operable pilot control valve 32 in the pilot line 31. The pilot control valve 32 includes a pilot outlet 33 connected by the pilot line 31 to the control valve 20, a low pressure inlet 35 connected to a source of relatively low pressure liquefied gas, namely to the vapour return line 12, and a high pressure inlet 34 connected to:the pressurised liquefied \ gas upstream of the valve 20. As shown the high pressure inlet 34 can be connected to the tank of the vapour remover 10. The pilot control valve 32 is selectively operable to connect either the low pressure inlet 35 to the pilot outlet 33 or the high pressure inlet 34 to the pilot outlet 33.

Preferably there is a normal fail-safe condition of the pilot control valve 32 which comprises connection of the low pressure inlet 35 to the pilot outlet 33, resulting in low pressure in the pilot line 31 and the control valve 20 being closed to liquefied gas flow therethrough.

The pilot control valve 32 may be electrically operable, e.g. solenoid operated, to switch between two conditions corresponding respectively to connection of the low pressure inlet 35 to the pilot outle.t 33 and connection of the high pressure inlet 34 to the pilot outlet 33. In- particular the solenoid has two states: (1) not energised - correspond! ng to connection of inlet 35 to outlet 33 and closure of inlet 34, resulting in low pressure in pilot line 31 and control valve 20 being closed to liquefied gas flow; and (2) energised - 9. 22 4 1 8 8 correspond!' ng to connection of inlet 34 to outlet 33 and closure of inlet 35, resulting in high pressure in pilot line 31 and opening of control valve 20 to liquefied gas flow therethrough.

The system shown in the drawing may be operated under control of a circuit (not shown) for energising and de-energising the solenoid of pilot control valve 32 .so as to cause the dispensing control valve 20 to open the supply line 15 for a short time interval following start-up of the supply pump and before dispensing through the filling coupling 16 commences so as to thereby allow pressurisation or purging of vapour in the supply line 15. This time interval mayibe in the order of one -two seconds. After this the control circuit causes the dispensing control valve 20 to close for a period during which the metering means 17 is reset to zero litres and zero cost. Subsequently the control circuit causes the dispensing control valve 20 to reopen for enabling metered dispensing of liquefied gas through the supply line 15 and filling coupling 16.

In the drawing there is also shown a second or duplicated series of components so that the illustrated system can enable two simultaneous dispensing operations. The repeated system components have the same reference numerals with the added suffix "a". The operation of the second series of components is exactly the same as the first series of components described above. However there is a single common, vapour remover 10 which is used for supplying liquefied gas to both the supply lines 15, 15a. This is- achieved by providing a supply junction 40 between the vapour remover tank 10 and the metering means 17, 17a. The supply junction 40 includes an inlet 41 and two outlets 42, 43 in communication with the inlet 41. Outlet 42 is connected to . supply line 15 and outlet 43 to supply line 15a. The inlet 41 of the supply junction 40 is in fluid communication with the bottom of liquid tank 10. This location of the inlet 41 enables duplicated components of the two dispensing lines to be closely arranged within a housing such as a standard fuel supply bowser provided at service stations. Normally with the outlet from the vapour eliminator tank 10 in the past being provided in the side of the tank 10, generally opposite the inlet 11, there has been insufficient space within the standard bowser casing for duplication of other components, at least without having a relatively long length of line from | the tank outlet to the measuring means 17, 17a. This length of line from the tank 10 to the measuring 17, 17a is preferably minimised in order to minimise vapour phase arising in that length of line which might interfere with metering accuracy and for this purpose the inlet 41 of the supply junction 40 is preferably closely connected to the bottom of the liquid tank 10 and the outlets 42, 43 are closely adjacent the respective metering means 17, 17a. In the drawing this distance from the bottom of the tank 10 to measuring means 17, 17a is merely illustrated schematically for describing the function of the system whereas in practice the physical distance would be minimised.

The preferred dispenser system illustrated in the drawing can be constructed and arranged^to overcome the leakage and user manipulation drawbacks of the prior art and also enables provision of two dispensing systems within the one standard service station bowser with minimised duplication of components. 22 4 1 8 It is to be . understood that various alterations, modifications and/or additions may be made to the features of the possible and preferred embodiment(s) of the invention as herein described without departing from the scope of the invention as defined in the appended claims. 224188 12.

Claims (13)

WHAT WE CLAIM IS:

1. A liquefied gas dispenser system including: a vapour remover for receiving liquefied gas from a supply and a pump associated with the supply and for separating gas phase from liquid phase; a supply line extending from the vapour remover to a filling coupling for connection to a destination for liquefied gas; metering means downstream of the vapour remover and operative to measure the amount of liquefied gas dispensed during a dispensing operation; and a dispensing control valve for controlling the flow of liquefied gas in the supply line between the metering means and the filling coupling, the control valve having an inlet port for receiving liquefied gas and an outlet port for the liquefied gas to be conveyed to the filling coupling, the control valve being operable to open the supply line if liquefied gas is pressurised upstream thereof, whereby liquefied gas dispensing flow can occur only if the liquefied gas is pressurised and whereby a significant liquefied gas pressure drop upstream of the control valve will result in closing of the supply line.

2. A dispenser system as claimed in Claim 1 wherein the control valve is a pilot operable control valve in selective communication via a pilot line with a source x £ a; • y !>» \- // o • C.\\ . i '•2 nf f14 MAR WOjl % J 224188 13. of pressurised pilot fluid, the pilot operable control valve being operable in response to the selective application of pilot fluid pressure in the pilot line to open the pilot operable control valve to allow liquefied gas flow from the inlet port to the outlet port of the pilot operable control valve.

3. A dispenser system as claimed in Claim 2 wherein the pilot line is selectively communicable with pressurised liquified gas upstream of the pilot operable control valve.

4. A dispenser system as claimed in Claim 3 wherein the pilot line is selectively communicable with the pressurised liquefied gas in the vapour remover.

5. A dispenser system as claimed in Claim 3 or 4 and further including a selectively operable pilot control valve for controlling application of pilot fluid pressure in the pilot line, the pilot operable control valve including a pilot outlet connected by the pilot line to the pilot line port of the pilot operable control valve, a low pressure inlet connected in use to a source of relatively low pressure liquefied gas, and a high pressure inlet connected in use to receive the pressurised liquefied gas from upstream of the pilot '* 'A A * f, V I •* I! nil { 14 MAR 1990*// \\ A' 224108 14. operable control valve; the pilot control valve being selectively operable to connect either the low pressure inlet to the pilot outlet or the high pressure inlet to the pilot outlet.

6. A dispenser system as claimed in Claim 5 and further including a vapour return line from the vapour remover to the liquefied gas supply, the low pressure inlet of the pilot control valve being connected in use to the vapour return line or to the liquefied gas supply upstream of the associated pump.

7. A dispenser system as claimed in claim 5 or 6 wherein the normal fail-safe condition of the pilot control valve comprises connection of the low pressure inlet to the pilot outlet.

8. A dispenser system as claimed in Claim 5, 6 or 7 wherein the pilot control valve is electrically operable to switch between two conditions corresponding respectively to connection of the low pressure inlet to the pilot outlet and a connection of the high pressure inlet to the pilot outlet.

9. A dispenser system as claimed in any preceding claim and further including an operation control ?24J88 15. circuit for causing the dispensing control valve to open the supply line for a short time interval following start-up of the supply pump and before dispensing through the filling coupling commences so as to thereby allow pressurisation or purging of vapour in the supply line, then to cause the dispensing control valve to close for a period during which the metering means is reset, then subsequently to cause the dispensing control valve to reopen for enabling dispensing of liquefied gas through the supply line and filling coupling.

10. A liquified gas dispenser system including: a vapour remover for receiving liquefied gas from a supply and a pump associated with the supply and for separating gas phase from liquid phase; a supply line extending from the vapour remover to a filling coupling for connection to a destination for liquefied gas; metering means downstream of the vapour remover and operative to measure the amount of liquefied gas dispensed therethrough during a dispensing operation; a dispensing control valve for controlling the flow of liquefied gas in the supply line between the metering means and the filling coupling, the control valve having an inlet port for receiving liquefied gas and an outlet port for the liquefied gas to be conveyed to the 224188 16. filling coupling; and a supply junction between the vapour remover and the metering means, the supply junction including an inlet and at least two outlets in communication with the inlet, a first one of the outlets being connected to the supply line, and a second outlet being connected to a second supply line, extending from the vapour remover to a second filling coupling for connection to a destination for liquefied gas; a second metering means downstream of the vapour remover and operative to measure the amount of liquefied gas dispensed therethrough during a dispensing operation, a second dispensing control valve for controlling the flow of liquefied gas in the second supply line between the second metering means and the second filling coupling, the second control valve having an inlet port for receiving liquefied gas and an outlet port for the liquefied gas to be conveyed to the second filling coupling, whereby a single common vapour remover is used for supplying liquefied gas to at least two supply lines and associated filling couplings for enabling two simultaneous dispensing operations to be carried out.

11. A dispenser system as claimed in Claim 10 wherein the vapour remover includes a liquid tank in which vapour phase is separated from liquid phase, the inlet 224188 17. of the supply junction being in fluid communication with the bottom of the liquid tank.

12. A dispenser system as claimed in Claim 11 wherein the inlet of the supply junction is closely connected to the bottom of the liquid tank and there are provided two outlets of the supply junction which are closely adjacent the respective metering means receiving liquefied gas from the two outlets whereby there is minimal distance for liquefied gas flow from the vapour remover to either of the two metering means.

13. A dispenser system substantially as herein before described with particular reference to the accompanying drawing. GAS CYLINDER SERVICES PTY. LIMITED By its attorneys HENRY HUGHES LIMITED per v-w