Claims
- 1. A vapor recovery system for use with systems for dispensing volatile liquids, such as liquid fuels, from a reservoir wherein the liquid is pumped under pressure through a hose and discharged through a vapor recovery dispensing nozzle into the inlet of a container such as a fuel tank, the novel vapor recovery system comprising
- a liquid jet gas pump having its liquid inlet in communication with the pressurized liquid so as to receive a portion thereof, and
- a vapor conduit having one end in said nozzle and adapted to be placed in communication with the interior of said container when said nozzle is inserted into said inlet and the other end in communication with the vapor inlet of said jet pump,
- the outlet of said jet pump discharging into said reservoir,
- whereby vapor displaced from said container as it is filled will be drawn off through said conduit by suction created by the passage of said liquid through said jet pump.
- 2. The vapor control system of claim 1 wherein said vapor conduit comprises a second hose having a predetermined outer diameter less than the inner diameter of said first hose and disposed within said first hose.
- 3. The vapor control system of claim 2 wherein said second hose has an inner diameter of about 5/16 inch (0.79 cm.) and an outer diameter of about 1/2 inch (1.27 cm.).
- 4. The vapor control system of claim 1 wherein said vapor conduit has a predetermined inner diameter and said liquid jet gas pump generates a predetermined degree of suction, said predetermined inner diameter and said predetermined degree of suction cooperating to produce a vapor velocity in said vapor conduit sufficient to entrain any liquid in said vapor conduit.
- 5. The vapor control system of claim 4 wherein said vapor conduit has an inner diameter of about 5/16 inch (0.79 cm.) and said jet pump generates a suction in the range of about 16 to about 20 inches (40 to 50 cm.) of water.
- 6. The vapor control system of claim 1 wherein said liquid jet gas pump includes
- a pilot valve between said liquid inlet and said outlet.
- 7. The vapor control system of claim 6 wherein said pilot valve is biased to a closed configuration in absence of a predetermined threshold pressure in said liquid inlet.
- 8. The vapor control system of claim 1 wherein said liquid jet gas pump includes
- an interior fuel passage for conducting the fuel through the pump, and
- a needle valve provided in said passage,
- said needle valve being biased toward a first position in which delivery of fuel through said fuel passage is substantially unblocked, and said needle valve moving toward a second position increasingly blocking the flow of fuel through said passage as the vacuum produced by said suction in said vapor conduit increases toward a predetermined maximum.
- 9. A liquid jet gas pump for use in a vapor recovery system of a liquid dispensing unit wherein the liquid is pumped under pressure from a reservoir through a hose and discharged through a vapor recovery dispensing nozzle into the inlet of a container, such as a fuel tank, the vapor displaced from said reservoir being withdrawn through a vapor conduit having one end in said nozzle and adapted to be placed in communication with the interior of said container when said nozzle is inserted into said inlet, the novel jet pump comprising
- a housing having a liquid inlet in communication with the pressurized liquid so as to receive a portion thereof, and a vapor inlet which communicates with the other end of said vapor conduit,
- a mixing tube fixed at one end to said housing and communicating with the interior thereof, and communicating at its other end with said reservoir,
- a surge chamber within said housing adjacent said mixing tube and communicating with said vapor conduit through said vapor inlet,
- a valve seat having a jet orifice,
- said valve seat being spaced within said housing adjacent said surge chamber,
- said jet orifice being positioned over said mixing tube and communicating therewith through said surge chamber,
- a passage within said housing communicating at one end with said fuel inlet and at its other end with said jet orifice,
- a pilot valve disposed within said passage,
- said pilot valve being biased to a closed position against said valve seat in absence of a predetermined pressure within said passage,
- a needle valve disposed within said passage over said jet orifice,
- said needle valve biased to a first position in which delivery of fuel from said passage through said jet orifice is substantially unblocked,
- said needle valve moving toward a second position which increasingly blocks the flow of fuel from said passage through said jet orifice as the vacuum level within said surge chamber increases to a predetermined maximum.
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of my U.S. patent application Ser. No. 553,529, "Vapor Control", filed Feb. 27, 1975, now U.S. Pat. No. 4,057,086, and of my U.S. patent application Ser. No. 656,124, "Vapor Control in a Fuel Dispensing Nozzle", filed Feb. 9, 1976, now U.S. Pat. No. 4,056,131, the benefit of which filing dates are herein claimed.
This invention relates to vapor recovery systems for preventing the escape of vapors to the atmosphere during the refilling of a volatile liquid container from a dispensing apparatus. In particular, this invention deals with a vapor recovery system for preventing the escape of hydrocarbon vapors from a vehicle's fuel tank during refueling from a service station's fuel dispensing unit.
A number of systems have been proposed for dealing with the vapors displaced from a volatile liquid container while it is being refilled, such as the hydrocarbon vapors displaced from a vehicle's fuel tank during a refueling operation.
Previous vapor recovery systems for recovering hydrocarbon vapors from a vehicle's fuel tank have included passages in the dispensing nozzle for collecting vapors from the fuel tank, as well as a vapor return line for delivery of the collected vapors to the reservoir. Each of these prior systems, however, has suffered from one or more of various drawbacks.
Some of these systems have relied solely upon vapor pressure within the fuel tank to push the vapor through the vapor return line. Such systems required a large and cumbersome vapor return line to minimize resistance to vapor flow. Additionally, when that return line became blocked by liquid (e.g., from fuel splashback or condensation), the vapor pressure developed in the vehicle fuel tank was usually insufficient to overcome the blockage. The result was vapor leakage to the atmosphere at the nozzle-fuel tank interface.
Other systems used for fuel dispensing have employed a vacuum-assist for drawing vapor through a vapor return line. To avoid the expense of a separate vacuum pump at each dispensing station, such systems have typically resorted to a powerful, continuously-operating blow-type vacuum pump and a complicated arrangement of electrically actuated valves for connecting the various vapor return lines to the vacuum pump when the various pumps were actuated for dispensing. Acceptance of these systems has been minimal because of the expense and difficulty of both installation and maintenance. Additionally such systems typically draw such a large volume of ambient air, relative to the volume of fuel vapor, that there is a danger of an explosive mixture being formed.
Finally, it has been suggested that each dispensing unit include a vacuum pump driven by the dispensing unit's conventional meter and connected to a vapor return line. However, the well-known fragility of such meters renders suspect the practicality of this suggestion.
I provide a simple, foolproof, and inexpensive vapor recovery system for use with systems for dispensing volatile liquids, such as liquid fuels, from a reservoir wherein the liquid is pumped under pressure through a hose and discharged through a vapor recovery dispensing nozzle into the inlet of a container, such as a fuel tank, the novel vapor recovery system comprising a liquid jet gas pump having its liquid inlet in communication with the pressurized liquid so as to receive a portion thereof, and a vapor conduit having one end in the nozzle and adpated to be placed in communication with the interior of the container when the nozzle is inserted into the inlet and the other end in communication with the vapor inlet of the jet pump, the outlet of the jet pump discharging into the reservoir, whereby vapor displaced from the container as it is filled will be drawn off through the conduit by suction created by the passage of the liquid through the jet pump.
In preferred embodiments the vapor conduit comprises a second hose having a predetermined outer diameter less than the inner diameter of the first hose and disposed within the first hose; the second hose has an inner diameter of about 5/16 inch and an outer diameter of about 1/2 inch; the vapor conduit has a predetermined inner diameter and the jet pump generates a predetermined degree of suction cooperating to produce a vapor velocity in the vapor conduit sufficient to entrain any liquid in the vapor conduit; the vapor conduit has an inner diameter of 5/16 inch and the jet pump generates a suction in the range of 16 to 20 inches of water; a pilot valve is provided in a passage within the jet pump, between its liquid inlet and its outlet; the pilot valve is biased to a closed configuration in absence of a predetermined threshold pressure in the passage and moves to an open position when the threshold pressure is reached; a needle valve is provided in the passage; the needle valve is biased toward a first position in which delivery of liquid through the jet pump is substantially unblocked, and the needle valve moves toward a second position which increasingly blocks the flow of liquid through the jet pump as the vacuum within the vapor conduit increases.
My invention is useful for many types of systems for dispensing volatile liquids, and is especially useful for a fuel service station's conventional dispensing units. It is easily and inexpensively installed in existing dispensing systems, and is compatible with systems having conventional leak detection devices. It provides for reliably effective vapor removal without forming an explosive mixture or endangering the container being filled by exposing it to excessive vacuum levels which could cause it to collapse.
Other advantages and features of the invention will be apparent from the description and drawings herein of a preferred embodiment thereof.
The structure and operation of a preferred embodiment of the invention is as follows.
US Referenced Citations (6)
Related Publications (1)
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656124 |
Feb 1976 |
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Continuation in Parts (1)
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553529 |
Feb 1975 |
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Patent Grant
4095626
