Vapor recovery system for fuel dispenser

Abstract

A system for recovering vapor and liquid emerging from a tank as it is being filled, in which the volumetric flow of a recovery pump that withdraws the vapor through a recovery tube is made equal to the volumetric flow of a fuel delivery pump with a microprocessor. The microprocessor can also modify the volumetric flow of the recovery pump in response to variations in the hydraulic pressure at the inlet side of the recovery pump.

Description

indicated by the dashed line 55.

Whereas the system thus far described works well under some conditions, improved operation is obtained under other conditions by making the volumetric vapor flow greater or less than the volumetric fuel flow. If the temperature of the fuel delivered to the vehicle tank is the same as the temperature of the fuel in the vehicle tank, satisfactory operation may be attained by making the volumetric flow of the vapor recovery means equal to the volumetric fuel flow, but, if for example, the fuel in the vehicle tank is cooler, it will be warmed up as the delivery continues so as to produce more vapor than it would if the temperatures were the same so that the volumetric flow of the vapor recovery means 36, 44 should be increased. The inverse of this situation occurs if the temperature of the fuel in the vehicle tank is warmer than the fuel being delivered.

In the embodiments of the invention shown in FIGS. 1 and 2, a pressure transducer 38 provides a signal P corresponding to the pressure at the inlet of the vapor recovery pump 36. With any given design, P would have a known nominal value X if the volume of vapors emitted from the tank equalled the volume of fuel being delivered, as might be the case if the temperature of the fuel in the vehicle tank and the fuel being delivered were the same. But, if the volume of vapor is greater than the volume of fuel being delivered, the pressure P would be greater than X, and conversely, if the volume of the vapor is less than the volume of the fuel being delivered, P would be less than X. Referring again to FIG. 3 FIG. 5, we find the following.

If P=X, as determined by a decision block 58, the recovery pump 38 is considered to be operating at the correct speed and the repetition rate V is not changed, i.e. V is the output with V=F as in step 60.

If, however, P<X, the recovery pump 36 is running too fast, and the repetition rate V of the drive pulses is reduced, for example, by one pulse a second, step 62, i.e. to (V-1).

In the event that P>X, the pressure P is compared with an excess pressure Y, as indicated in a decision block 64.

If P≦Y, the repetition rate V is increased, for exampie, by one pulse a second, i.e. to (V+1), step 66, but if P>Y, the dispenser is shut down, via step 52. Thus if P>Y, the dispenser is shut down.

Means other than those illustrated in FIGS. 1 and 2 could be used to carry out the various functions.

The recovery pump could be driven by a D.C. motor rather than a stepping motorin which case the microprocessor 34 could be programmed to provide a signal that would select an appropriate one of a number of different D.C. voltages for application to the motor.

Instead of varying the speed of the motor driving the recovery pump 36, the vapor recovery means 36, 38 could have a valve or damper that is controlled by the microprocessor 34 so as to suck out the desired volume of vapor.

Whereas the use of the pressure P at the inlet of the recovery pump 36 is a satisfactory indication of the flow produced by the vapor recovery means, other indications could be used, e.g. a vapor flow meter could provide electrical signals indicative of the flow.

Although various embodiments of the invention have been illustrated and described herein, they are not meant to be limiting. Modifications to these embodiments may become apparent to those of skill in the art, which modifications are meant to be covered by the spirit and scope of the appended claims. For example, in the coaxial hose, the center hose could be the vapor hose, and the space between the inner and outer hose can be used to convey fuel in a system including the invention.

Claims

1. A fuel delivery system including:

fuel delivery means having a variable volumetric flow;

means for providing an electrical signal indicative of the volumetric flow of said fuel delivery means;

a vapor recovery means pump having a controllable volumetric flow, said vapor recovery means pump having means for sucking vapor at a first end and for ejecting it at a second end; and

means responsive to said electrical signal for making the volumetric flow of said vapor recovery means pump the same as the volumetric flow of said fuel delivery means.

2. A fuel delivery system as set forth in claim 1 further including:

means for deriving a second electrical signal indicative of the volumetric flow of vapor in said vapor recovery means pump;

means providing a third electrical signal indicative of the volumetric flow of said vapor recovery means pump under given conditions;

means for comparing said second and third signals;

means for increasing the volumetric flow of said vapor recovery means pump if the comparison indicates that the volumetric flow of said vapor recovery means pump is less than the flow under the given conditions; and

means for decreasing the volumetric flow of said vapor recovery means pump if the comparison indicates that the volumetric flow of said vapor recovery means pump is greater than the flow under the given conditions.

3. A fuel delivery system as set forth in claim 2 wherein:

the signal indicative of the volumetric flow of said vapor recovery means pump corresponds to a pressure at the first end of said vapor recovery means pump.

4. A fuel delivery system as set forth in claim 3, further including:

means for reducing the volumetric flow of said fuel delivery means to zero if the signal representing said pressure exceeds a given value.

5. In a system for delivering vaporizable liquid into an opening of a tank in such manner as to recover liquid and vapor that escapes from the opening, the combination comprising:

a delivery hose;

a nozzle connected to one end of said delivery hose for controlling the flow of said liquid into said tank;

first pumping means coupled to the other end of said delivery hose;

means coupled between said delivery hose and said pumping means for providing a first electrical signal representing the volumetric flow of fuel through said delivery hose;

a recovery hose;

second pumping means coupled to said recovery hose for drawing vapor through said recovery hose;

transducer means coupled to an inlet of said second pumping means for providing a second electrical signal representing a hydraulic pressure in said recovery hose; and

control means for said second pumping means including an electrical signal processor, said control means being responsive to said first electrical signal for initially making the volumetric flow of said second pumping means equal to the volumetric flow in said delivery hose and responsive to said second electrical signal for modifying the volumetric flow of said second pumping means as required to maintain said hydraulic pressure in said recovery hose within a given range of values.

6. In a system for delivering liquid into an opening of a tank in such manner as to recover vapor that may emanate from said opening, the combination comprising:

a liquid delivery hose;

a first pump coupled to said delivery hose so as to be capable of forcing a flow of liquid through it;

a recovery hose;

a second pump coupled to said recovery hose so as to be capable of withdrawing a flow of liquid and vapor through it, said second pump having an inlet side;

signalling means for providing an electrical signal indicative of the volumetric flow in one of said hoses; and

control means responsive to said signal for controlling the one of said pumps coupled to the other hose in such manner that it produces the same volumetric flow in said other hose as that in said one hose.

7. The combination as set forth in claim 6, wherein:

said signalling means provides an electrical signal in the form of indicator pulses having a repetition rate corresponding to the volumetric flow in said one hose;

a motor for driving the one of said pumps coupled to said other hose, said motor having a speed corresponding to the repetition rate of drive pulses applied to it;

drive means for supplying drive pulses to said motor; and

said control means responding to said indicator pulses to make the drive means provide drive pulses having the required repetition rate.

8. The combination as set forth in claim 7, wherein the required repetition rate of drive pulses to said motor is the same as the repetition rate of the indicator pulses.

9. The combination as set forth in claim 6, further comprising:

means coupled to an inlet side of said second pump for providing a second signal indicative of the pressure thereat; and

means for maintaining the volumetric flow of said second pump at the same value if the second signal indicates that the pressure equals a nominal value.

10. The combination as set forth in claim 6, further comprising:

means coupled to an inlet side of said second pump for providing a second signal indicative of the pressure thereat; and

means responsive to said second signal for reducing the volumetric flow of said second pump if the second signal indicates a pressure less than a nominal value.

11. The combination as set forth in claim 6, further comprising:

means coupled to an inlet side of said second pump, for providing a second signal indicative of the pressure thereat; and

means responsive to said second signal for increasing the volumetric flow of said second pump if the second signal indicates a pressure greater than a nominal value and less than an excessive value.

12. The combination as set forth in claim 7 10, further comprising means for preventing wherein said control means prevents delivery of liquid if a second signal indicates a pressure said pressure is greater than an excessive value.

13. In a system for delivering vaporizable liquid into an opening of a tank in such manner as to recover liquid vapor that may emanate from said opening during delivery, the combination comprising:

a liquid delivery hose;

a liquid delivery pump coupled to said delivery hose;

metering means coupled to one of said delivery hose and said delivery pump for providing pulses occurring at a repetition rate corresponding to the volumetric flow of liquid through said delivery hose; a recovery hose for liquid and vapor;

a recovery pump, a motor coupled to drive said recovery pump, said recovery pump producing a volumetric flow through said recovery hose corresponding to a repetition rate of drive pulses applied to said motor;

a source of drive pulses that may be varied in repetition rate coupled to said motor; and

processor control means responsive to the pulses provided by said means for metering, for controlling the repetition rate of drive pulses provided by said source of drive pulses so as to cause said recovery pump to have the same volumetric flow as said liquid delivery pump.

14. In a system for delivery vaporizable liquid into an opening of a tank in such manner as to recover liquid and vapor that may emanate from said opening during delivery, the combination comprising:

a liquid delivery hose;

a pump coupled to said delivery hose so as to be capable of forcing a flow of liquid through it;

a vapor recovery hose;

a pump coupled to said vapor recovery hose so as to be capable of withdrawing a flow of vapor and liquid through it;

means for providing an electrical signal indicative of the volumetric flow in said delivery hose; and

means responsive to said signal for controlling said recovery pump in such manner that it produces a flow in said recovery tube having the same volumetric rate as the volumetric rate in said delivery hose.

15. In a system for delivering vaporizable liquid into an intake pipe of a tank in such manner as to recovery recover fumes or liquid emanating thereform during the delivery process, the combination comprising:

a liquid delivery hose;

means coupled to said delivery hose for providing electrical indication of the volumetric flow through it;

a chamber for collecting any fumes or liquid emanating from the intake pipe when coupled thereto;

a recovery tube communicating with said chamber;

a recovery pump of the displacement type, communicating with said recovery tube; and

means responsive to said electrical indications indication for driving said recovery pump at a speed such that it has a derived volumetric flow as the volumetric flow in said delivery tube.

16. A fuel delivery system including:

fuel delivery means having a variable volumetric flow;

means for providing an electrical signal indicative of the volumetric flow of said fuel delivery means;

a vapor recovery means having a controllable volumetric flow, said vapor recovery means having a variable speed pump for sucking vapor at a first end and for ejecting it at a second end;

and means responsive to said electrical signal for driving the pump at a speed to make the volumetric flow of said pump be derived from the volumetric flow of said fuel delivery means.

17. A fuel delivery system as claimed in claim 16 further comprising a fuel dispenser housing and wherein said fuel delivery means includes a liquid fuel delivery path including a pump to pump liquid from a fuel reservoir along said path to a hose for conveying liquid which is attached to said housing and which terminates in a nozzle, and

a vapor recovery path including a vapor recovery hose portion located within said liquid-conveying hose from said nozzle to said housing so that the space between the vapor recovery hose and the liquid-conveying hose can be used to convey liquid fuel from said housing to said nozzle, as vapor is returned from said nozzle to said housing.

18. In a system for delivering vaporizable liquid into an intake pipe of a tank in such manner as to recover fumes or liquid emanating therefrom during the delivery process, the combination comprising:

a liquid delivery hose terminating in a nozzle;

means coupled to said delivery hose for providing an electrical indication of the volumetric flow through said delivery hose;

an intake port in said nozzle for collecting any fumes emanating from the intake pipe when coupled thereto;

a recovery tube communicating with said intake port;

a recovery pump communicating with said recovery tube;

and means responsive to said electrical indications for driving said recovery pump at a speed such that it has a volumetric flow derived from the volumetric flow in said delivery hose.

19. A vapor recovery fuel dispenser comprising

a liquid fuel delivery means including means for monitoring the flow rate of the liquid fuel being delivered and outputting a control signal indicative of the liquid flow rate,

a vapor recovery apparatus including a vapor recovery line through which vapor to be recovered is transported and a variable speed pump to pump vapor through said vapor recovery line, and

an electrical control for said variable speed pump to control the speed of said pump and, in turn, the rate of vapor pumping to correlate with said control signal indicative of the liquid flow rate. 20. A method of liquid fuel delivery including:

delivering fuel with a variable volumetric flow;

providing an electrical signal indicative of the volumetric flow of the fuel delivery;

withdrawing vapor at a first end of a pump driven by a variable speed motor having a controllable volumetric flow and ejecting it at a second end; and

controlling the volumetric flow rate of the vapor as derived from the electrical signal by controlling the speed of the motor. 21. A fuel delivery method as claimed in claim 20 comprising the preliminary step of providing a coaxial hose having inner and outer pathways through which to deliver fuel and withdraw vapor and

said fuel delivering step comprises delivering the fuel through the outer pathway of the coaxial hose, and

said vapor withdrawing step comprises withdrawing the vapor through the

inner pathway of the coaxial hose. 22. In a process for delivering vaporizable liquid into an opening of a tank in such manner as to recover vapor that may emanate from the opening, the combination comprising:

pumping a flow of liquid through a delivery hose with a first pump;

withdrawing a flow of vapor through the recovery hose with a second pump driven by a motor to produce a volumetric flow through the recovery hose corresponding to a signal applied to the motor;

providing pulses occurring at a repetition rate corresponding to the volumetric flow of liquid through the delivery hose; and

controlling the signal applied to the motor responsive to the pulses, to cause the recovery pump to have a volumetric flow derived from the volumetric flow of the liquid delivery pump. 23. A fuel delivery system including:

fuel delivery means having a variable volumetric flow;

means for providing an electrical signal indicative of

the volumetric flow of said fuel delivery means; vapor recovery means having a controllable volumetric flow, said vapor recovery means having a positive displacement pump and a variable speed motor arranged to drive said positive displacement pump for sucking vapor at a first end and for ejecting it at a second end; and

a controller responsive to said electrical signal for making the speed of said motor be derived from a value of the volumetric flow of said fuel delivery means without withdrawing excess air. 24. A fuel delivery system as claimed in claim 23, wherein said vapor recovery means includes a variable speed vapor pump capable of pumping a variable volumetric rate of vapor and said controller varies the pumping speed of the pump. 25. A fuel delivery system including:

a dispensing nozzle having a gas outlet and a vapor inlet;

a fuel conduit connecting the gas outlet of the dispensing nozzle to a fuel supply;

a fuel pump for delivering fuel to the dispensing nozzle through the fuel conduit;

a flow meter disposed in the fuel conduit for sensing the flow rate of the fuel and for generating an electrical signal indicative of the flow rate of the fuel;

a controller operatively connected to the flow meter for generating a control signal derived from the electrical signal from the flow meter;

a vapor conduit connected to the vapor inlet of the nozzle for directing vapor from the dispensing nozzle;

a variable flow control unit including a vapor pump for drawing vapor through the vapor conduit; and

a stepper motor operatively connected to the flow control unit and responsive to the control signal from the controller for controlling the flow rate of the vapor through the flow control unit. 26. The fuel delivery system of claim 25 wherein the stepper motor drives the vapor pump and is operative to vary the speed of the vapor pump in

response to the control signal. 27. The fuel delivery system as claimed in claim 25 wherein the variable flow control unit withdraws vapor without air. 28. A method of delivering fuel including:

pumping fuel from a fuel supply through a conduit and out of a nozzle having a fuel outlet and a vapor inlet;

returning vapor from the vapor inlet of the nozzle though a vapor conduit

sensing the flow rate of the fuel through the conduit to generate an electrical signal indicative of the flow rate of the fuel;

generating a control signal derived from the electrical signal;

drawing vapor through the vapor conduit; and

actuating a stepper motor responsive to the control signal to control the flow rate of the vapor through the flow control unit. 29. The fuel delivery method of claim 28 wherein the actuation of the stepper motor drives a vapor pump to vary the speed of the vapor pump in response to the control signal. 30. The fuel delivery method as claimed in claim 28 wherein the vapor drawing step withdraws vapor without

air. 31. A fuel delivery system comprising:

a dispensing nozzle having a liquid fuel inlet, a liquid fuel outlet, a vapor inlet and a vapor outlet;

a first conduit having a first end adapted for connection to a fuel pump associated with a fuel storage tank and a second end at said liquid fuel inlet of said nozzle;

a vapor pump having a vapor inlet and a vapor outlet;

a second conduit operatively connected between said nozzle vapor outlet and the vapor inlet of said vapor pump;

a third conduit having a first end operatively connected to said vapor outlet of said vapor pump and a second end adapted for connection to said fuel storage tank;

a means for providing electrical signals respresentative of fuel flow rate through said first conduit, and

drive means operatively connected to said vapor pump so as to drive it to produce a desired vapor flow rate in response to said electrical signals derived from said means for providing electrical signals. 32. In a system for delivering vaporizable liquid into an intake pipe of a tank in such manner as to recover fumes emanating from the tank during the delivery process, the combination comprising:

a liquid delivery path terminating in a nozzle;

a meter coupled to said delivery path and driving a pulser that generates pulses indicative of the volumetric flow through said delivery path;

an intake port in said nozzle for collecting fumes emanating from the intake pipe when coupled thereto;

a recovery path communicating with said intake port;

an electrically driven variable speed vapor pump arranged to pump vapor along said recovery path; and

a control responsive to said pulses and outputting an electrical signal to drive said variable speed pump at a speed such that it has a volumetric flow derived from the volumetric flow in said delivery path.

33. A vapor recovery fuel dispenser comprising

a liquid fuel delivery apparatus including a device that monitors the flow rate of the liquid fuel being delivered and outputs a first control signal indicative of the liquid flow rate,

a vapor recovery apparatus including a vapor recovery line through which vapor to be recovered is transported and a variable speed pump to pump vapor through said vapor recovery line,

a sensor that monitors the vapor being recovered and outputs a second control signal affected by the vapor flow rate, and

a control for said variable speed pump to control the rate of vapor pumping to correlate with said control signal indicative of the liquid flow rate and to compensate for deviations indicated by said second control signal.