PRODUCT RETURN SYSTEM

Abstract: A bulk fluid delivery system comprising a plurality of storages (1) volumes each connected to the inlet of a pump via a selector valve (3) and a duct, a metering means (5) to measure the output of the pump (4) and a delivery hose (7) connected to the outlet of the pump and having a delivery nozzle (8) at its end remote from the pump (5), the system further comprising return pipe (10) means extending from an inlet nozzle (11) to communicate selectively with one of the storage volumes (1), the delivery nozzle (8) being connectable to the inlet nozzle (11) to deliver fluid into the inlet nozzle (11).

Description: PRODUCT RETURN SYSTEM The present invention relates to fluid delivery systems, and is particularly concerned with the metered delivery of bulk liquids from, for example, road tanker vehicles. Delivery of bulk liquids such as fuel oil, kerosene, lubricating oil, etc from tanker vehicles is conventionally achieved by providing the tanker vehicle with a tank having a number of internal compartments, each of which can hold a different bulk liquid. Outlet pipes are connected from each of the internal divisions of the tank to the inlet of a pump, via a selector valve. The outlet of the pump is delivered to a metering device, and thence to a delivery tube. In conventional arrangements, the delivery tube is mounted on a hose reel, and is positioned either between the tank and the vehicle cab, or at the rear of vehicle. When an amount of liquid is to be delivered from the vehicle to a receiving container, the appropriate internal division of the tank is selected using the selector valve, and the delivery hose is connected to the receptacle into which the liquid is to be delivered. Operating the pump causes liquid to flow from the tank into the receiving container, through the meter which records the amount of liquid delivered. At the end of the delivery, a valve at the distal end of the delivery hose is closed and the hose is wound back onto the reel, still filled with the last liquid delivered. When the tanker is to make its next delivery, if the liquid to be delivered is different from that delivered on the last call, the delivery system comprising the pump, the meter and the delivery hose, must first be emptied of the previous liquid and filled with the new liquid to be delivered. This is usually done by the tanker operator climbing onto the top of the tank, and inserting the end of the delivery hose into the internal division of the tank containing the liquid last delivered. The operator then selects the new liquid to be delivered, and operates the pump so as to draw off enough of the new liquid to fill the delivery system. This volume is a constant known volume and thus by delivering this amount of the new liquid, the pump, the meter and the delivery hose are purged of the previous liquid, which is returned to the tank. The tanker operator may then attach the delivery hose to the receiving container, and operate the pump to deliver the amount of the new liquid required. Clearly, such procedures of purging the delivery hose are time-consuming, particularly in single man operated vehicles. The possibility exists of the operator returning the purged liquid to the wrong compartment of the tank, and thus contaminating its contents. There is also a risk of the operative becoming injured or falling from the top of the tanker vehicle, particularly when liquids such as lubricating oil are being handled as spillages invariably occur. It is an objective of the present invention to provide a product return system which enables rapid purging of the delivery system without the need for the tanker operator to climb on top of the vehicle carrying a heavy hose, and can be automated to prevent contamination. According to a first aspect of the present invention, a bulk fluid delivery system comprises a plurality of storage volumes each connected to the inlet of a pump via a selector valve and a duct, a metering means to measure the output of the pump, and a delivery hose connected to the outlet of the pump and having a delivery nozzle at its end remote from the pump, the system further comprising return pipe means extending from an inlet nozzle to communicate selectively with one of the storage volumes, the delivery nozzle being connectable to the inlet nozzle to deliver fluid into the inlet nozzle. The selector means may be a hose connected at one end to the inlet of the pump, and connectable at its other end to a respective one of the outlets of the storage volumes. Alternatively, each storage volume may have its outlet connected via a duct to a selector valve which is operable to connect a selected one of the outlets to the pump inlet. According to a second aspect of the invention, a purging system for a fluid delivery installation, which includes a number of storage tanks selectively connectable through a meter to a delivery nozzle, comprises an inlet nozzle and duct means selectively connecting the inlet nozzle to one of the storage volumes. Preferably, the duct means comprises a single duct having branches extending into all of the storage volumes, each branch having a valve operable to connect the duct to the storage volume. The storage volumes may be internal compartments within a tank, or may be separate tanks. The duct means may be equipped with a pressurised gas reservoir through a valve operable to inject pressurised gas into the duct to expel fluids therein. An embodiment of the invention will now be described in detail, with reference to the accompanying drawings, in which: Figure 1 shows schematically the ducting layout of a first embodiment of the system; and Figure 2 shows schematically a second embodiment of the system. Referring now to Figure 1 , a tank of, for example, a road tanker vehicle is generally designated by reference numeral 1. The tank 1 is divided into four internal divisions of differing volumes, 1a, 1 b, 1c and 1d, but may be divided only into two, or into a larger number of divisions. Each of the internal divisions is provided with a respective delivery duct 2a, 2b, 2c and 2d. The delivery ducts 2a to 2d lead from the tank 1 to a selector valve 3. The arrangement of the selector valve 3 is such that any one of the ducts 2a to 2d may be connected to the outlet of the selector valve 3, while the other three ducts are closed off. The outlet of the selector valve 3 leads to the inlet of a pump 4, which delivers liquid to metering device 5 and thence to a delivery hose reel 6 on which is coiled a flexible delivery hose 7. A delivery nozzle 8 is fitted to the end of the delivery hose 7. As an alternative to the valve 3, a hose attached to the inlet of the pump 4 may be selectively connectable to one of the outlet ducts 2a to 2d. In order to deliver a liquid from one of the internal divisions of the tank 1 , the selector valve or hose 3 is operated to connect the relevant duct 2a to 2d to the pump 4, and the pump 4 is then operated until the meter 5 shows that the required amount of liquid has been delivered. Clearly, the internal divisions 1a to 1d of the tank 1 may contain different liquids. When the pump 4, meter 5, and delivery hose 7 are filled with a first liquid, for example from division 1a, and a second liquid, for example from division 1 b, is to be delivered, then the delivery system, comprising of pump 4, meter 5 and hose 7 must be cleared of the first liquid and filled with the second. This is generally done by arranging for the delivery system to be purged as it completes one delivery with the liquid to be delivered at the next call. If, however, the delivery cannot be completed, the purging can be done using the purging system of the present invention, which comprises a return pipe 10, which leads from an inlet nozzle 11 to the tank 1. The return pipe 10 includes a valve 12 situated adjacent to the nozzle 11 to prevent any liquid flowing back out of the nozzle 11. Adjacent the valve 12 is a further valve 14, which has two operating positions. In a first operating position, the valve 14 allows fluid to pass from the non-return valve 12 along the vertical section of the return pipe 10. In its second operating position, the valve 14 connects a high-pressure air reservoir 13 to the interior of the return pipe 10. The return pipe 10 is connected to each of the internal divisions of the tank 1 by means of a respective valve 15a to 15d. When the delivery system 3, 4, 5, 6, 7, 8 is filled with a first liquid, and a second liquid is to be delivered, the tanker operator connects the delivery nozzle 8 to the inlet nozzle 11 , and sets valve 14 into its first position. One of the valves 15 is opened, to connect the return pipe 10 with the division 1 a to 1d into which the liquid from the delivery system is to be discharged. The selector valve 3 is then operated to select the new liquid to be delivered, and the pump 4 is then operated to deliver a volume of liquid equal tσ the volume contained in the delivery system 3, 4, 5, 6, 7, 8. This causes the first liquid which is within the delivery system 3, 4, 5, 6, 7, 8 to be ejected through the nozzle 8, and into the return pipe 10. This liquid then flows through the return pipe 10, and out of the appropriate valve 15 to be delivered into the sub-division 1a of the tank 1 from whence the first liquid was drawn. When the required volume has been passed through the meter 5, the pump 4 is stopped. The delivery hose 7 is now filled with the second liquid, and the delivery nozzle 8 may be disconnected from the inlet nozzle 11 and used to make the delivery of the second liquid. In order to clear the return pipe 10 of any remaining first liquid, the valve 14 is moved to its second position and high-pressure air from the reservoir 13 is admitted into the return pipe 10 to blow through any remaining liquid into the appropriate division of tank 1 through its respective valve 15. Clearly, the return pipe 10 may be blown through either before or after the nozzle 8 is disconnected. Advantageously, the inlet nozzle 11 is positioned at a convenient location to the tanker operator, preferably adjacent the delivery hose reel 6. This enables the delivery nozzle 8 to be connected to the input nozzle 11 with the delivery hose 7 accommodated on the reel 6. It is further foreseen that a mechanical, electrical, or other interlock may prevent operation of the purging system unless the delivery nozzle 8 is connected to inlet nozzle 11. Although the system described above includes a single inlet nozzle 11 , linked by a single return pipe 10 to all of the internal divisions 1a to 1d of the tank via respective valves, it is foreseen that each sub-division 1a to 1d of the tank may have its own dedicated return pipe 10 and its own dedicated input nozzle 11. This will avoid the need for valves 15, but will require the delivery nozzle 8 to be connected to the correct inlet nozzle 11 for each purging operation. In a further alternative, the inlet nozzle 11 may be connected to a second selector valve similar to the selector valve 3, which is linked to each division of the tank 1 by a respective return pipe. In a preferred embodiment of the invention, the valves 15 and the selector valve 3 are linked to control circuitry which includes memory means to store information in relation to the last liquid to be delivered. Input means are provided to the control circuity which allow the operator to select the liquid to be delivered, and the control circuitry then compares the liquid to be delivered with the liquid previously delivered. If they are different, the control circuitry will operate the selector valve 3 and the relevant valve 15, and will control the operation of the pump 4 to deliver a metered amount of the new liquid into the delivery hose 7, once the delivery nozzle 8 has been connected to the input nozzle 11. The control circuitry may also operate the valve 14 to blow the remaining liquid out of the return pipe 10 when the necessary volume of new liquid has been delivered to fill the delivery system 3, 4, 5, 6, 7, 8. The tanker operator may then disconnect the delivery nozzle 8 from the input nozzle 11 , and proceed with the delivery of the new liquid to the customer. If the system is operated in such a way that, at the end of each delivery the tanker operator connects the delivery nozzle 8 to the input nozzle 11 , and if the control circuitry includes its input means positioned within the tanker's cab, it can be foreseen that after each delivery the operator can simply connect delivery nozzle 8 to the input nozzle 11 , and then enter the cab and drive to the next delivery point. While in transit, it will be possible for the operator to select the next liquid to be delivered and the system can automatically undertake any purging of the delivery system 3, 4, 5, 6, 7, 8 and return pipe 10 while the tanker is in motion. This will ensure that, when the tanker arrives at the next delivery point the delivery system 3, 4, 5, 6, 7, 8 is already filled with the correct liquid for delivery to commence. Operating time will therefore be saved, increasing the efficiency of the vehicle. While the delivery system has been described above in relation to bulk liquids such as fuel oils, kerosene, etc, it is foreseen that the system can equally well be applied to other liquids or to gases in gaseous or liquid form. It is further foreseen that a conventional tanker vehicle may be fitted with the return pipe 10 of the present invention, in order to convert an existing tanker vehicle to a vehicle operating the delivery system of the present invention. Figure 2 shows an alternative embodiment of the return system, similar to that of Figure 1. In the embodiment shown in Figure 2, the inlet nozzle 11 and non-return valve 12 are connected, via an air valve 14, to a second selector valve or valves 20 whose outlets are connected to respective outlet ducts 2a, 2b, 2c and 2d from the tank 1. Non-return valves (not shown in detail) may be provided and as indicated in Figure 2 at 10a, 10b, 10c and 10d, in the ducts downstream of selector valve or valves 20. In use, selector valve or valves 20 are used in place of valves 15 to direct the liquid back into its correct compartment. If the length of ducting between inlet the nozzle 11 and the selector valve or valves 20 is sufficiently small, the gas cylinder 13 and valve 14 may be omitted. Control of the various valves 3, 14, 15 and 20 may be by manual operating handles or handwheels, or by actuators such as hydraulic or electromechanical or pneumatic actuators. Control of the operation of the valves 3, 14, 15 and 20 and the pump 4 may be manual, with the operator controlling the various valves and pump in the correct sequence. Alternatively, the system may be automated by placing the valves and pump under microprocessor control.

Claims: CLAIMS 1. A bulk fluid delivery system comprising a plurality of storage volumes each connected to the inlet of a pump via a selector valve and a duct, a metering means to measure the output of the pump, and a delivery hose connected to the outlet of the pump and having a delivery nozzle at its end remote from the pump, the system further comprising return pipe means extending from an inlet nozzle to communicate selectively with one of the storage volumes, the delivery nozzle being connectable to the inlet nozzle to deliver fluid into the inlet nozzle. 2. A system as claimed in claim 1 in which the selector means is a hose connected at one end to the inlet of the pump and connectable at its other end to a respective one of the outlets of the storage volumes. 3. A system as claimed in claim 1 in which each volume has its outlet connected via a duct to a selector valve which is operable to connect a selected one of the outlets to the pump inlet. 4. A purging system for a fluid delivery installation which includes a number of storage tanks selectively connectable through a meter to a delivery nozzle, comprising an inlet nozzle and duct means selectively connecting the inlet nozzle to one of the storage volumes. 5. A system as claimed in claim 4 in which the duct means comprises a single duct having branches extending into all of the storage volumes each branch having a valve operable to connect the duct to the storage volume. 6. A system as claimed in claim 5 in which the storage volumes are internal compartments within a tank or are separate tanks. 7. A system as claimed in claim 6 in which the duct means are equipped with a pressurised gas reservoir through a valve operable to inject pressurised gas into the duct to expel fluids therein.

Inventors: BREWER LESLIE WILLIAM, GILLESPIE ERIC BRIAN, LUCAS FREDERICK GEORGE GRAHAM, MIHELL DEREK, BREWER, LESLIE, WILLIAM, GILLESPIE, ERIC, BRIAN, LUCAS, FREDERICK, GEORGE, GRAHAM, MIHELL, DEREK
Applicants: MAIDMENT TANKER SERVICES LIMIT, MAIDMENT TANKER SERVICES LIMITED
Application year: 1998
Main classification: B60P3
IPC codes: B60P3, B67D5