Fluid handling – With leakage or drip collecting
Reexamination Certificate
1997-10-09
2001-05-01
Walton, George L. (Department: 3753)
Fluid handling
With leakage or drip collecting
C137S315010, C141S059000, C141S086000, C141S198000, C222S067000, C222S110000, C222S318000
Reexamination Certificate
active
06223765
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to the dispensing of fuels and more particularly to a novel casing which provides an interface for the flow pipes and electrical conductors in a fuel dispensing system.
BACKGROUND OF THE INVENTION
At gasoline service stations and other facilities that dispense fuel, underground tanks are commonly installed for storage of the fuel. A submersible electric pump operates to pump the fuel through a vertical column pipe when the dispenser is activated. The fuel is then delivered to a dispensing line which extends to a dispenser having a nozzle that discharges the fuel under the control of the service station attendant or customer.
The fuel path includes an interface between the column pipe and the dispensing line. Electrical power must also be supplied to the submersible pump from a power source which may be located in a building or other area. Conventionally, an assembly referred to as a packer or a manifold forms the interface section of the flow path and also allows electrical lines to extend through the column pipe in an electrical conduit leading to the pump.
The packer/manifold assemblies that have been used in the past have not been altogether without problems. Any fuel that leaks from the piping should be contained, and packers have not always been able to provide satisfactory containment. Consequently, leaking fuel can contaminate the area and can create environmental problems and violations of regulatory laws. Excess vapor pressure from the fuel can also cause similar problems.
The packer assembly is normally equipped with a check valve which holds the line pressure to the dispenser in order to assure that fuel is immediately available for each dispensing cycle. Proper maintenance procedures require that the check valve be inspected and serviced at suitable intervals. Often, it is necessary to disassemble and reassemble a number of components in order to obtain access for removal of the check valve. The complexity of this procedure adds to the maintenance costs and the down time of the equipment.
The column pipe and pump must also be removed and serviced periodically. Again, this can be a complicated procedure because the components of the packer assembly between the column pipe and the check valve must be disconnected and then reconnected after maintenance operations have been completed. Tools are required for assembly and disassembly of the components, and this adds both to the cost of the maintenance and to the time the system is out of service.
SUMMARY OF THE INVENTION
The present invention is directed to a casing which provides an improved flow interface between the column pipe and the dispensing pipe and also provides an improved electrical interface between the power leads and the supply wires extending to the submersible pump.
In accordance with the invention, a fluid tight casing has a threaded connection with a riser pipe extending from an underground fuel storage tank. A power head mounted in the casing has a threaded connection with a column pipe through which fuel is pumped from the tank by a submersible pump. An electrical conduit extending in the column pipe contains electrical wiring for operating of the pump. The power head provides a flow path for the fuel that turns through a 90° angle within the casing.
A check valve housing is mounted in the casing and connects with a dispensing pipe which leads to the fuel dispenser. Fuel from the power head flows into the check valve housing through a check valve which is urged toward a closed position by a spring that allows the check valve to open under the influence of the force of the fluid when the pump is in operation. The check valve is mounted on a post and stem assembly directly carried on a lid for the valve housing. As a result, the check valve can be removed along with the lid in order to facilitate servicing of the check valve and related components.
The flow path from the power head and check valve housing is equipped with a quick connect coupling that can be clamped and unclamped without the need for tools. Consequently, when the casing cover is removed, the coupling can be unclamped and the power head, column pipe and pump can be withdrawn from the casing as a unit for servicing.
The casing is fluid tight and is thus able to serve a secondary containment function to contain any fuel leaking from the flow line. A float valve opens a drain to return fuel to the tank when the accumulation of fuel on the floor of the casing reaches a selected level. Excessive fuel vapor in the casing is likewise returned to the tank through a pressure relief valve. Excess pressure downstream from the check valve is relieved by an expansion relief valve, and the fuel in this relief line is directed back to the tank through the power head.
Due to the unique construction and arrangement of the casing and the components associated with it, leaking fuel is contained and returned to the tank, excessive vapor pressure is relieved, and the safety of the fuel dispensing system is enhanced by these features, as well as by an intrinsic safety barrier plug which is installed in the casing to isolate the electrical lines from the fuel. In addition, removal and servicing of the components can be carried out quickly and easily to minimize the maintenance costs while providing ready access to the parts that require periodic maintenance.
REFERENCES:
patent: 3183723 (1965-05-01), Deters
patent: 3905405 (1975-09-01), Fowler et al.
patent: 3913633 (1975-10-01), Hiller
patent: 3915206 (1975-10-01), Fowler et al.
patent: 3981335 (1976-09-01), Deters
patent: 4256151 (1981-03-01), Gunn
patent: 4508139 (1985-04-01), Teumer
patent: 4842163 (1989-06-01), Bravo
patent: 5301721 (1994-04-01), Hartmann
patent: 5673732 (1997-10-01), Kenney et al.
Clark G. Todd
Schwan Robert Joe
Small Dorsey D.
Traver Martin J.
Young David S.
Marley Pump
Shook Hardy & Bacon LLP
Walton George L.
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