Control system for temperature compensated vapor recovery in gasoline dispenser

• US 5,156,199 A
• Filed: 01/21/1992
• Issued: 10/20/1992
• Est. Priority Date: 12/11/1990
• Status: Expired due to Term

• Current Assignee: Gilbarco Incorporated (Vontier Corp.)
• Original Assignee: Gilbarco Incorporated (Vontier Corp.)
• Inventors: Pope, Kenneth L., Hartsell, Hal C. Jr.
• Primary Examiner(s): Cusick, Ernest G.
• Application Number:
  US07/824,702
• Time in Patent Office: 273 Days
• Field of Search: 141/1, 141/4, 141/5, 141/44, 141/51, 141/59, 141/83, 141/192, 141/198
• US Class Current: 141/83
• CPC Class Codes: B67D 7/0486 Pumps driven in response to electric signals indicative of pressure, temperature or liquid flow
• CPC Class Codes: B67D 7/32 Arrangements of safety or warning devices; Means for preventing unauthorised delivery of liquid

Abstract

A system for recovering vapor emerging from a tank to which liquid is being delivered wherein a vapor pump sucks vapor from the tank with a volumetric flow that is equal to the volumetric flow of the liquid as modified so as to compensate for the change in volume of the emerging vapor caused by its proximity to the entering liquid, and apparatus for measuring the actual vapor flow and adjusting the volumetric flow of the vapor pump so that it is equal to the flow required for ideal compensation.

Claims

1. A liquid delivery system, comprising:

a liquid delivery path adapted for engagement with a tank to be filled,

means for delivering liquid to the tank along said liquid delivery path with a variable volumetric flow;

means for providing and electrical signal indicative of said volumetric flow;

a second path that is adjacent to said liquid delivery path;

vapor recovery means responsive to said electrical signal for sucking vapor from the tank along said second path with a nominal volumetric flow corresponding to the volumetric flow;

means for deriving second and third signals respectively representing the absolute temperatures of liquid in said liquid delivery path and vapor entering said second path; and

means responsive to said second and third signals for increasing the volumetric flow of the vapor recovery means when the temperature of the liquid is greater than the temperature of vapor and for decreasing the volumetric flow to the vapor recovery means when the temperature of the liquid is less than the temperature of vapor.

2. A liquid delivery system as set forth in claim 1 further comprising:

means for determining from said second and third signals an indication of the ideal volumetric flow of vapor required to remove the vapor displaced from the tank by delivery of the liquid thereto;

means for providing an indication of the actual volumetric flow of vapor produced by said vapor recovery means; and

means responsive to said indication of the ideal vapor flow and the indication of the actual vapor flow for modifying the volumetric flow produced by said vapor recovery means so that it is equal to the ideal volumetric flow.

9. A liquid delivery system as set forth in claim 1 wherein said means for deriving said third signal includes a thermal transducer exposed to ambient air.

3. For a fuel dispensing system, the method comprising the steps of:

delivering fuel to a tank along a first path with a variable volumetric flow;

producing an electrical signal indicative of the volumetric flow;

sucking vapor from the tank in response to the electrical signal, along a second path that is adjacent to the first path with a nominal volumetric flow corresponding to the volumetric flow;

producing second and third signals respectively representing the absolute temperatures of fuel in the first path and vapor entering the second path; and

increasing the volumetric flow of the vapor being sucked, in response to said second and third signals, if the temperature of the fuel is greater than the temperature of vapor and decreasing the volumetric flow of the vapor being sucked, in response to said second and third signals, if the temperature of the fuel is less than the temperature of vapor.

4. The method of claim 3, further comprising the steps of:

calculating from said second and third signals an indication of the ideal volumetric flow of vapor required to remove the vapor displaced from the tank by delivery of the fuel thereto;

producing an indication of the actual volumetric flow of vapor produced by sucking back vapor at a given time; and

adjusting the volumetric flow of sucking back vapor in response to said indication of the ideal vapor flow and the indication of the actual vapor flow for equating the rates of actual vapor flow and ideal vapor flow.

5. A fuel delivery system comprising:

a first conduit,

a fuel delivery pump adapted for withdrawing fuel form a fuel reservoir and forcing it along said first conduit;

a meter coupled to said first conduit for providing a first signal indicative of the volumetric flow of fuel in said first conduit;

a second conduit,

a vapor recovery pump for withdrawing vapor along said second conduit;

driving means for said vapor recovery pump;

a controller responsive to said first signal for causing said driving means to drive said vapor recovery pump so that is has an initial nominal volumetric flow corresponding to the volumetric flow of fuel in said first conduit;

a first transducer means for deriving a second signal indicative of the temperature of fuel in said first conduit;

a second transducer means for deriving a third signal indicative of the temperature of vapor in said second conduit; and

said controller also being responsive to said second and third signals for deriving a motor control signal which when applied to said driving means modifies the initial nominal volumetric flow provided by said vapor recovery pump in such manner as to reduce the difference int he volume of vapor emerging from a tank to which fuel is being delivered and the volume of the vapor passing through said vapor recovery pump.

6. A system as set forth in claim 5, further comprising:

a housing;

a vapor barrier mounted in said housing that divides it into non-hazardous and hazardous zones;

said fuel delivery pump, said meter, said first conduit, and said first transducer means for deriving said second signal being within said hazardous zone;

said vapor recovery pump and said second conduit being within said hazardous zone;

said controller and said driving means being within said non-hazardous zone;

means for coupling said second signal from said first transducer means to said controller through said vapor barrier; and

mechanical means extending through said vapor barrier for coupling said driving means for said vapor recovery pump to said vapor recovery pump.

7. A system as set forth in claim 6, further comprising:

a flow meter coupled to said second conduit for providing a fourth signal indicative of the volumetric flow of vapor through said second conduit;

means for coupling said fourth signal through said vapor barrier to said controller; and

said controller being programmed to provide a signal to said driving means so as to further modify the volumetric flow of said vapor recovery pump in such manner that it actually equals the amount theoretically required to compensate for the difference in volume of vapor emerging from the tank to which fuel is being delivered and the volume of the vapor passing through the vapor recover pump.

8. A fuel delivery system as set forth in claim 7, further comprising:

a hose having a first tube having one end coupled to a nozzle and the other end coupled to said first conduit and a second tube having one end coupled to said nozzle and the other end coupled to said second conduit; and

said nozzle having manually controllable means for varying the volumetric flow of said fuel delivery pump.

10. A fuel delivery system as set forth in claim 5 wherein said second transducer is exposed to ambient air.