Inferential flow meter for use in fuel dispensing environments

1. Apparatus for measuring fluid flow comprising:

an inferential flow meter having a housing defining a fluid flow path;

a pulser operative to produce an output signal indicative of flow rate through said meter;

a controller in electronic communication with said pulser so as to receive said output signal; and

based on said output signal, said controller being operative to determine said fluid flow in a plurality of dynamic time sub-windows corresponding to respective periods of substantially consistent instantaneous flow, and to sum the fluid flow from each of the plurality of dynamic time sub-windows to compute a delivered volume of fluid.

2. Apparatus as set forth in claim 1 , wherein said output signal of said pulser comprises a pulse train in which pulse frequency varies with said instantaneous flow.

3. Apparatus as set forth in claim 2 , wherein said dynamic time sub-windows are ascertained by comparing duration between adjacent pulses.

4. Apparatus for measuring fluid flow comprising:

an inferential flow meter having a housing defining a fluid flow path;

a pulser operative to produce an output signal indicative of flow rate through said meter;

a controller in electronic communication with said pulser so as to receive said output signal; and

based on said output signal, said controller being operative to determine said fluid flow in a plurality of dynamic time sub-windows corresponding to respective periods of substantially consistent instantaneous flow,

wherein said output signal of said pulser comprises a pulse train in which pulse frequency varies with said instantaneous flow,

wherein said dynamic time sub-windows are ascertained by comparing duration between adjacent pulses, and

wherein said controller is operative to include a series of said adjacent pulses in one of said dynamic time sub-windows if respective durations therebetween are within a threshold of each other.

5. Apparatus as forth in claim 1 , wherein said inferential flow meter is a turbine meter having at least one rotor.

6. Apparatus as set forth in claim 5 , wherein said rotor rotates about a fixed shaft located in said housing.

7. Apparatus as set forth in claim 1 , including a magnetic detector affixed to said housing at a location adjacent to said rotor.

8. Apparatus for measuring fluid flow comprising:

a turbine flow meter having a rotor;

a pulser operative to produce a pulse train in which pulse rate varies with instantaneous flow through said turbine flow meter;

a controller operative to determine a total volume of fluid passing through said turbine flow meter during a time period, said controller configured to perform the steps of:

(a) determining a first partial volume based on a first pulse rate during a first time sub-window;

(b) determining a second partial volume based on a second pulse rate during a second time sub-window; and

(c) adding said first partial volume and said second partial volume.

9. Apparatus as set forth in claim 8 , wherein said first and second time sub-windows are dynamically determined corresponding to respective periods in which said first pulse rate and said second pulse rate remain substantially consistent.

10. Apparatus as set forth in claim 9 , wherein said first pulse rate and said second pulse rate remain consistent within a predetermined threshold during said first and second time sub-windows, respectively.

11. Apparatus as set forth in claim 9 , wherein said pulse rates within each of said time sub-windows are averaged during determination of said first and second partial volumes to filter out spurious variations.

12. A method of determining flow of a fluid through an inferential flow meter, said method comprising steps of:

(a) detecting a pulse train having a plurality of pulses occurring at a pulse rate indicative of fluid flow rate through said inferential flow meter;

(b) determining pulse rates of said plurality of pulses;

(c) grouping adjacent pulses having substantially consistent pulse rates into a plurality of time sub-windows;

(d) calculating respective partial volumes for each of said time sub-windows; and

(e) adding said respective partial volumes to determine a total delivered volume.

13. A method of determining flow of a fluid through an inferential flow meter, said method comprising steps of:

(a) detecting a pulse train having a plurality of pulses occurring at a pulse rate indicative of fluid flow rate through said inferential flow meter;

(b) determining pulse rates of said plurality of pulses;

(c) grouping adjacent pulses having substantially consistent pulse rates into a plurality of time sub-windows;

(d) calculating respective partial volumes for each of said time sub-windows; and

(e) adding said respective partial volumes to determine a total delivered volume,

wherein said substantially consistent pulse rates are those occurring within a predetermined threshold of each other.

14. A method as set forth in claim 12 , wherein said pulse rates within each of said time sub-windows are averaged during determination of said partial volumes to filter out spurious variations.

15. A fuel dispenser comprising:

a fluid flow conduit for delivering fuel from a storage tank;

a hose having a proximal end and a distal end, said proximal end in fluid communication with said fluid flow conduit;

a nozzle connected to said distal end of said hose;

an inferential flow meter located in line said fluid flow conduit;

a pulser associated with said inferential flow meter to produce an output signal indicative of flow rate through said inferential flow meter; and

a controller in electronic communication with said pulser so as to receive said output signal; and

based on said output signal, said controller being operative to determine fluid flow in a plurality of dynamic time sub-windows corresponding to respective periods of substantially consistent instantaneous flow, and to sum the fluid flow from each of the plurality of dynamic time sub-windows to compute a delivered volume of fluid.

16. A fuel dispenser as set forth in claim 15 , wherein said output signal of said pulser comprises a pulse train in which pulse frequency varies with said instantaneous flow.

17. A fuel dispenser as set forth in claim 6 , wherein said dynamic time sub-windows are ascertained by comparing duration between adjacent pulses.

18. A fuel dispenser comprising:

a fluid flow conduit for delivering fuel from a storage tank;

a hose having a proximal end and a distal end, said proximal end in fluid communication with said fluid flow conduit;

a nozzle connected to said distal end of said hose;

an inferential flow meter located in line said fluid flow conduit;

a pulser associated with said inferential flow meter to produce an output signal indicative of flow rate through said inferential flow meter; and

a controller in electronic communication with said pulser so as to receive said output signal; and

based on said output signal, said controller being operative to determine fluid flow in a plurality of dynamic time sub-windows corresponding to respective periods of substantially consistent instantaneous flow,

wherein said output signal of said pulser comprises a pulse train in which pulse frequency varies with said instantaneous flow,

wherein said dynamic time sub-windows are ascertained by comparing duration between adjacent pulses, and

wherein said controller is operative to include a series of said adjacent pulses in one of said dynamic time sub-windows if respective durations therebetween are within a threshold of each other.

19. A fuel dispenser as forth in claim 15 , wherein said inferential flow meter is a turbine meter having at least one rotor.

20. A fuel dispenser as set forth in claim 19 , wherein said rotor rotates about a fixed shaft located in a housing of said turbine meter.

21. A fuel dispenser as set forth in claim 20 , including a magnetic detector affixed to said housing at a location adjacent to said rotor.