Fluid flow meter with normalized output

• US 10,260,923 B2
• Filed: 07/25/2017
• Issued: 04/16/2019
• Est. Priority Date: 07/25/2017
• Status: Active Grant

• Current Assignee: Ecolab USA Incorporated (Ecolab, Inc.)
• Original Assignee: Ecolab USA Incorporated (Ecolab, Inc.)
• Inventors: Tokhtuev, Eugene, Schilling, Paul S.
• Primary Examiner(s): Dowtin, Jewel V
• Application Number:
  US15/658,437
• Publication Number:
  US 20190033114A1
• Time in Patent Office: 630 Days
• CPC Class Codes: G01F 15/0755 involving digital counting
• CPC Class Codes: G01F 25/10 of flowmeters
• CPC Class Codes: G01F 3/10 Geared or lobed impeller meters
• CPC Class Codes: G01F 3/24 with measuring chambers moved during operation wet gas-meters G01F3/30

Abstract

A fluid flow meter is described, that includes intermeshing gears that may rotate synchronously. The fluid flow meter may produce a pulsed output that can be normalized to suitable values according to a method of normalizing input pulses generated in response to the rotation of gears. A volume counter can be incremented by an amount equal to a volume per input pulse each time an input pulse is generated. When the volume counter exceeds a first reference volume, a normalized output pulse can be generated until the volume counter exceeds a second reference volume.

Claims

1. A fluid flow meter, comprising;

a flow chamber;

a first gear intermeshing with a second gear, the first gear and the second gear being positioned within the flow chamber, the intermeshing of the first gear and the second gear permitting synchronous rotation of the first gear and the second gear in response to flow of a fluid through the flow chamber;

a flow sensor configured to generate a detection signal in response to the passage of fluid through the flow chamber and/or synchronous rotation of the first gear and the second gear; and

a controller having an input pulse generator and a normalized output pulse generator, the controller being configured to

receive detection signal from the flow sensor,

cause the input pulse generator to generate input pulses when detection signal is received from the flow sensor,

increment a volume counter by an amount equal to a volume per input pulse each time an input pulse is generated,

transition the normalized output pulse generator from a state where the normalized output pulse generator does not generate output pulses to a state where the normalized output pulse generator starts generating a normalized output pulse when the volume counter exceeds a first reference volume, and

transition the normalized output pulse generator from a state where the normalized output pulse generator generates a normalized output pulse back to a state where the normalized output pulse generator stops generating the normalized output pulse.

2. The fluid flow meter of claim 1, wherein the controller is configured to decrease the volume counter by the first reference volume each time when or after the normalized output pulse is generated.

3. The fluid flow meter of claim 1, wherein the controller is configured to determine whether volume counter corresponds to the first reference volume, and if the volume counter corresponds to the first reference volume, the normalized output pulse generator is further configured to generate a single normalized output pulse until the volume counter corresponds to a second reference volume.

4. The fluid flow meter of claim 3, wherein, when the volume counter exceeds the second reference volume the controller is further configured to decrease the volume counter by the second reference volume.

5. The fluid flow meter of claim 4, wherein the controller is further configured to transition the normalized output pulse generator to a state where the normalized output pulse generator generates a subsequent normalized output pulse when the volume counter subsequently reaches first reference volume.

6. The fluid flow meter of claim 1, wherein a measurement accuracy of the fluid flow meter is +/−

Δ

V, whereby Δ

V is approximately equal to the first reference volume.

7. The fluid flow meter of claim 1, wherein the controller is configured to transition the normalized output pulse generator from a state where the normalized output pulse generator generates normalized output pulses for a duration corresponding to one-half of a pulse cycle, such that the fluid flow meter has a duty cycle of 50% for normalized output pulse generation.

8. The fluid flow meter of claim 1, wherein the controller is configured to increment the volume counter by non-integer values each time an input pulse is generated.

9. The fluid flow meter of claim 1, further comprising a non-transitory data storage medium operatively connected to the controller, the non-transitory data storage medium being configured to store the non-integer value by which the volume counter is to be incremented when an input pulse is generated.

10. The fluid flow meter of claim 9, wherein the non-integer values correspond to a volume passing through the fluid flow meter when the flow sensor generates an input pulse.

11. The fluid flow meter of claim 1, wherein a measurement resolution of the fluid flow meter is approximately equal to the first reference volume.

12. A method of providing a normalized output for a fluid flow meter, comprising:

providing a fluid flow meter, comprising;

a flow chamber,

a first gear intermeshing with a second gear, the first gear and the second gear being positioned within the flow chamber, the intermeshing of the first gear and the second gear permitting synchronous rotation of the first gear and the second gear in response to flow of a fluid through the flow chamber,

a flow sensor, and

a controller having an input pulse generator and a normalized output pulse generator;

receiving a detection signal from the flow sensor;

generating, input pulses using the input pulse generator when a detection signal from the flow sensor is received by the controller;

increment a volume counter by an amount equal to a volume per input pulse each time an input pulse is generated;

transition the normalized output pulse generator from a state where it does not produce a normalized output pulse to a state where it starts producing the normalized output pulse when the volume counter exceeds a first reference volume; and

transition the normalized output pulse generator from a state where it produces the normalized output pulse to a state where it stops producing the normalized output pulse when the volume counter exceeds a second reference volume.

13. The method of claim 12, wherein a volume corresponding to normalized output pulse is M, the first reference volume is M/2, and the second reference volume is M.

14. The method of claim 12, wherein the flow sensor generates a detection signal when the rotation of the first gear and the second gear correspond to a predetermined valid rotational state.

15. A method of providing a normalized output for a fluid flow meter, comprising:

providing a fluid flow meter, comprising;

a flow chamber,

a first gear intermeshing with a second gear, the first gear and the second gear being positioned within the flow chamber, the intermeshing of the first gear and the second gear permitting synchronous rotation of the first gear and the second gear in response to flow of a fluid through the flow chamber, and

a controller having an input pulse generator and a normalized output pulse generator;

generating input pulses using the input pulse generator when a non-integer value of volume passing through the fluid flow meter;

incrementing a volume counter by an amount equal to the non-integer value of volume passing through the flow meter when an input pulse is generated;

transitioning the normalized output pulse generator from a state where it does not produce a normalized output pulse to a state where it starts producing the normalized output pulse when the volume counter exceeds a first reference volume; and

transitioning the normalized output pulse generator from a state where it produces the normalized output pulse to a state where it stops producing the normalized output pulse when the volume counter exceeds a second reference volume, whereby,

the first reference volume is one-half of the second reference volume.

16. The method of claim 15, wherein the non-integer value is an average pulse rate for input pulses.

17. The method of claim 15, wherein the second reference volume is a non-zero integer.

18. The method of claim 15, wherein a frequency of normalized output pulses is less than a frequency of the input pulses.

19. The method of claim 15, wherein a frequency of normalized output pulses is less than a frequency of the input pulses.