Regulator flow measurement apparatus

• US 6,539,315 B1
• Filed: 06/23/2000
• Issued: 03/25/2003
• Est. Priority Date: 06/29/1999
• Status: Expired due to Term

• Current Assignee: Fisher Controls International LLC (Emerson Electric Company)
• Original Assignee: Fisher Controls International LLC (Emerson Electric Company)
• Inventors: Woollums, David E., Adams, Paul R., Milliken, Jon B.
• Primary Examiner(s): Barlow, John
• Assistant Examiner(s): Cherry, Stephen J.
• Application Number:
  US09/603,474
• Time in Patent Office: 1,005 Days
• Field of Search: 702/45, 702/47, 702/100, 137/487.5, 731/99, 738/614.7, 738/615.8
• US Class Current: 702/47
• CPC Class Codes: G01F 1/363 with electrical or electro-mechanical indication G01F1/37 and G01F1/38 take precedence
• CPC Class Codes: G01F 1/383 with electrical or electro-mechanical indication
• CPC Class Codes: G01F 1/40 Details of construction of the flow constriction devices
• CPC Class Codes: G01F 1/42 Orifices or nozzles
• CPC Class Codes: G05D 16/2095 using membranes within the main valve
• CPC Class Codes: Y10T 137/7761 Electrically actuated valve
• CPC Class Codes: Y10T 137/8158 With indicator, register, recorder, alarm or inspection means
• CPC Class Codes: Y10T 137/8326 Fluid pressure responsive indicator, recorder or alarm

Abstract

Apparatus for determining fluid flow through a pressure regulator is disclosed. The pressure regulator is disposed in a fluid flow passage and has a throttling element moveable in the flow passage. A stem is attached to the throttling element. The apparatus includes a first pressure sensor for measuring pressure upstream of the throttling element, a second pressure sensor for measuring pressure downstream of the throttling element, and a travel sensor for detecting the position of the throttling element. A processor is provided which includes a stored algorithm for determining flow rate based on the measured pressure and travel values.

Claims

1. A pressure regulator comprising:

a body defining a fluid flow passage;

an actuator housing attached to the body and having an actuator disposed therein, the actuator being in fluid communication with the fluid flow passage;

a throttling element moveable in the flow passage and attached to the actuator;

a first pressure sensor in fluid communication upstream of the throttling element for measuring an upstream pressure P₁;

a second pressure sensor in fluid communication downstream of the throttling element for measuring a downstream pressure P₂;

a travel indicator for determining a throttling element position Y; and

a processor associated with the first pressure sensor, second pressure sensor, and travel sensor, the processor having a stored program for determining a flow rate F based on the upstream pressure P₁, the downstream pressure P₂, and the throttling element position Y.

2. The apparatus of claim 1, further comprising a temperature sensor for measuring a temperature T of the fluid, wherein the stored program determines flow rate F in accordance with:

$F=\sqrt{\frac{K_1}{G*T}}*K_2*Y*P_1$

where

K₁ is a temperature constant,

G is a specific gravity of the fluid, and

K₂ is a throttling element position constant.

3. The apparatus of claim 2, in which the fluid flow is sub-critical, and the flow rate algorithm is multiplied by a further function $\sin $

 



K3

P1-P2P1

wherein K₃ is a trim shape constant.

4. The apparatus of claim 2, in which the throttling element comprises a flexible member, and in which the constant K₂ is a function of P₁-P₂.

5. The apparatus of claim 2, in which the throttling element comprises a non-linear trim valve member, and in which the constant K₂ is a function of throttling element position Y.

6. The apparatus of claim 2, in which the throttling element comprises a non-linear trim valve member, and in which the constant K₂ is a function of upstream pressure P₁, downstream pressure P₂, and throttling element position Y.

7. The apparatus of claim 2, further comprising a memory structure operably coupled to the processor for storing digital data concerning operation of the pressure regulator, and a communications circuit operably coupled to the processor for communicating at least some of the stored digital data to an outside communication device.

8. The apparatus of claim 7, in which the processor includes a logic sub-routine for comparing stored digital data to current digital data to obtain diagnostic data corresponding to the operation of the pressure regulator.

9. The apparatus of claim 8, in which the processor includes a logic sub-routine for comparing at least two of the upstream pressure P₁, downstream pressure P₂, and stem position Y and generates an alarm signal in accordance with a logic sub-routine.

10. The apparatus of claim 9, in which the logic sub-routine generates an alarm when the stem position Y equals zero and the downstream pressure P₂ is increasing.

11. The apparatus of claim 9, in which the logic sub-routine generates an alarm when the stem position Y is greater than zero and the downstream pressure P₂ is decreasing.

12. The apparatus of claim 9, in which the logic sub-routine generates an alarm when the stem position Y is greater than zero and the upstream pressure P₁ is increasing.

13. The apparatus of claim 9, in which the logic sub-routine generates an alarm when the stem position Y is greater than zero and the downstream pressure P₂ is greater than a user entered downstream pressure limit.

14. The apparatus of claim 9, in which the logic sub-routine generates an alarm when the flow rate F is greater than a user entered flow rate limit.

15. The apparatus of claim 1, in which the travel sensor comprises a hall effect sensor.

16. The apparatus of claim 1, in which the pressure regulator further comprises a stem attached to the throttling element, and in which the stored program infers throttling element position Y by measuring a position of the stem.

17. The apparatus of claim 1, in which the fluid comprises a liquid, and in which the stored program determines the liquid flow rate F in accordance with:

$F=\sqrt{\frac{K_1}{G*T}}*K_2*Y*\sqrt{P_1-P_2}$

where

K₁ is a temperature constant,

G is a specific gravity of the liquid,

T is a temperature of the liquid, and

K₂ is a throttling element position constant.

18. The apparatus of claim 17, in which the throttling element comprises a non-linear trim valve member, and in which the throttling element position constant K₂ is a function of throttling element position Y.

19. A method for determining fluid flow through a pressure regulator, the method comprising the steps of:

providing a body defining a fluid flow passage;

providing an actuator housing attached to the body and having an actuator disposed therein, the actuator being in fluid communication with the fluid flow passage;

providing a throttling element moveable in the flow passage and attached to the actuator;

generating an upstream pressure value P₁ by measuring fluid pressure upstream of the throttling element;

generating a downstream pressure value P₂ by measuring fluid pressure downstream of the throttling element;

generating a travel value Y by determining a position of the throttling element; and

calculating a fluid flow value F based on the upstream pressure value P₁, downstream pressure value P₂, and travel value Y.

20. The method of claim 19, further comprising the step of generating an absolute temperature value T by measuring the temperature of the fluid, wherein the fluid flow value F is calculated in accordance with:

$F=\sqrt{\frac{K_1}{G*T}}*K_2*Y*P_1,\text{\hspace{1em}<br><br>}<br><br>\mathrm{where}$

K₁ is an absolute temperature constant,

G is a specific gravity of the fluid, and

K₂ is a stem position constant.

21. The apparatus of claim 20, in which the fluid flow is sub-critical, and the flow rate algorithm is multiplied by a further function $\sin $

 



K3

P1-P2P1

wherein K₃ is a trim shape constant.

22. The method of claim 20, in which the pressure regulator is an elastomeric style regulator, and in which the constant K₂ is a function of P₁-P₂.

23. The method of claim 20, in which the throttling element comprises a non-linear trim valve member, and in which the constant K₂ is a function of throttling element position Y.

24. The method of claim 20, in which the throttling element comprises a non-linear trim valve member, and in which the constant K₂ is a function of upstream pressure P₁, downstream pressure P₂, and throttling element position Y.

25. The method of claim 20, in which the pressure regulator comprises a flexible diaphragm connected to the throttling element, and in which the apparatus includes a third pressure sensor for measuring a gauge loading pressure P_L on the diaphragm, and the stored program calculates flow rate F by substituting the gauge loading pressure P_L and a loading pressure constant K₄ for the throttling element position Y and throttling element position constant K₂, respectively.

26. The method of claim 20, in which the throttling element comprises a flexible member, and in which the apparatus includes a third pressure sensor for measuring a gauge loading pressure P_L on the flexible member, and the stored program calculates flow rate F by substituting the gauge loading pressure P_L and a loading pressure constant K₄ for the throttling element position Y and throttling element position constant K₂, respectively.

27. The method of claim 26, in which the loading pressure constant K₄ is a function of upstream pressure P₁ minus downstream pressure P₂.

28. The method of claim 20, in which the throttling element comprises a non-linear trim valve member, and in which the apparatus includes a third pressure sensor for measuring a gauge loading pressure P_L on the non-linear trim valve member, and the stored program calculates flow rate F by substituting the gauge loading pressure P_L and a loading pressure constant K₄ for the throttling element position Y and throttling element position constant K₂, respectively.

29. The method of claim 28, in which the loading pressure constant K₄ is a function of gauge loading pressure P_L.

30. A pressure regulator comprising:

a body defining a fluid flow passage;

a throttling element moveable in the fluid flow passage and directly responsive to a pressure of fluid in the fluid flow passage;

a first pressure sensor in fluid communication upstream of the throttling element for measuring an absolute upstream pressure P₁;

a second pressure sensor in fluid communication downstream of the throttling element for measuring an absolute downstream pressure P₂;

a third pressure sensor for measuring a loading pressure P_L on the throttling element; and

a processor associated with the first pressure sensor, second pressure sensor, and third pressure sensor, the processor having a stored program for determining a flow rate F based on the upstream pressure P₁, downstream pressure P₂, and loading pressure P_L.

31. The apparatus of claim 30, further comprising a temperature sensor for measuring a temperature T of the fluid, wherein the stored program determines flow rate F in accordance with $F=\sqrt{\frac{K_1}{G*T}}*K_4*P_L*P_1*\sin $

 



P1-P2P1

where

K₁ is an absolute temperature constant,

G is a specific gravity of the fluid,

T is an absolute temperature of the fluid, and

K₄ is a loading pressure constant.

32. The apparatus of claim 31, in which the loading pressure constant K₄ is a function of upstream pressure P₁ minus downstream pressure P₂.

33. The apparatus of claim 31, in which the loading pressure constant K₄ is a function of gauge loading pressure P_L.

34. The apparatus of claim 30, in which the throttling element comprises a flexible member, and in which the third pressure sensor measures the loading pressure P_L on the flexible member.

35. The apparatus of claim 30, in which the throttling element comprises a non-linear trim valve member, and in which the third pressure sensor measures the loading pressure P_L on the non-linear trim valve member.

36. A pressure regulator comprising:

a body defining a fluid flow passage;

an actuator housing attached to the body and having an actuator disposed therein, the actuator being in fluid communication with the fluid flow passage;

a throttling element moveable in the flow passage and attached to the actuator;

a first pressure sensor in fluid communication upstream of the throttling element for measuring an absolute upstream pressure P₁;

a second pressure sensor in fluid communication downstream of the throttling element for measuring an absolute downstream pressure P₂;

a third pressure sensor for measuring a loading pressure P_L on the actuator; and

a processor associated with the first pressure sensor, second pressure sensor, and third pressure sensor, the processor having a stored program for determining a flow rate F based on the upstream pressure P₁, downstream pressure P₂, and loading pressure P_L.

37. The apparatus of claim 36, further comprising a temperature sensor for measuring a temperature T of the fluid, wherein the stored program determines flow rate F in accordance with $F=\sqrt{\frac{K}{G*T}}*K_4*P_L*P_1*\sin $

P1-P2P-1

where

K₁ is an absolute temperature constant,

G is a specific gravity of the fluid,

T is an absolute temperature of the fluid, and

K₄ is a loading pressure constant.

38. The apparatus of claim 36, in which the pressure regulator actuator comprises a flexible diaphragm, and in which the third pressure sensor measures the loading pressure P_L on the diaphragm.