Best-fit affinity sensorless conversion means or technique for pump differential pressure and flow monitoring

• US 9,938,970 B2
• Filed: 04/07/2015
• Issued: 04/10/2018
• Est. Priority Date: 12/16/2011
• Status: Active Grant

• Current Assignee: Fluid Handling LLC (Xylem, Inc.)
• Original Assignee: Fluid Handling LLC (Xylem, Inc.)
• Inventors: Cheng, Andrew A., Gu, James J., Scott, Graham A.
• Primary Examiner(s): LaBalle, Clayton E
• Assistant Examiner(s): BUTLER, KEVIN C
• Application Number:
  US14/680,667
• Publication Number:
  US 20160010639A1
• Time in Patent Office: 1,099 Days
• Field of Search: 73168
• CPC Class Codes: F04B 17/03 driven by electric motors
• CPC Class Codes: F04B 49/065 and making use of computers
• CPC Class Codes: F04B 49/103 Responsive to speed
• CPC Class Codes: F04B 49/106 Responsive to pumped volume
• CPC Class Codes: F04B 51/00 Testing machines, pumps, or pumping installations
• CPC Class Codes: F04D 15/0088 Testing machines
• CPC Class Codes: F05D 2270/304 Spool rotational speed
• CPC Class Codes: F05D 2270/335 Output power or torque
• CPC Class Codes: F15B 19/00 Testing; Calibrating; Fault detection or monitoring; Simulation or modelling of fluid-pressure systems or apparatus not otherwise provided for
• CPC Class Codes: F16K 37/0075 For recording or indicating the functioning of a valve in combination with test equipment
• CPC Class Codes: G01L 5/0061 Force sensors associated with industrial machines or actuators for the specific machine or actuator involved see relevant class, e.g. F01, F04, F16, B66, E21

Abstract

The present invention provides apparatus, including a hydronic sensorless pumping system, that features a signal processor or processing module configured to receive signaling containing information about motor readout values of power and speed, and also about pump and system characteristics equations together with empirical power equations that are constructed by a polynomial best-fit function together with pump affinity laws based upon a pump curve published by a pump manufacturer; and determine corresponding signaling containing information about a pump or system pressure and a flow rate at the motor readout values of power and speed, based upon the signaling received.

Claims

1. Apparatus for pump differential pressure and flow monitoring, comprising:

a signal processor or processing module configured at least to;

receive signaling containing information about motor readout values of power and speed, and also about pump and system characteristics equations together with empirical power equations that are constructed by a polynomial best-fit function together with pump affinity laws based upon a pump curve published by a pump manufacturer; and

determine corresponding signaling containing information about a pump or system pressure and a flow rate at the motor readout values of power and speed, based upon the signaling received.

2. Apparatus according to claim 1, wherein the signal processor or processing module is configured to resolve pump differential pressures and flow rate at an equilibrium point of the pump or system pressure at a motor steady state condition.

3. Apparatus according to claim 1, wherein the signal processor or processing module is configured to provide the corresponding signaling containing information about the pump or system pressure and the flow rate, including for pump differential pressure and flow monitoring.

4. Apparatus according to claim 3, wherein the corresponding signaling contains information used to control a hydronic pumping system.

5. Apparatus comprising:

a signal processor or processing module configured at least to;

receive signaling containing information about motor readout values of power and speed, and also about pump and system characteristics equations together with empirical power equations that are constructed by a polynomial best-fit function together with pump affinity laws based upon a pump curve published by a pump manufacturer; and

determine corresponding signaling containing information about a pump or system pressure and a flow rate at the motor readout values of power and speed, based upon the signaling received, wherein the signal processor or processing module is configured to;

resolve the pump or system pressure and the flow rate at a steady state equilibrium point of pump and system pressures which is at an intersection of pump and system curves functions determined,

determine or represent an instant pump characteristic curve, which is the pump differential pressure P with respect to flow rate Q and motor speed of n, using an approximation in a polynomial form of P=f(Q,n) based upon a pump curve at a motor full speed n_max as well as the pump affinity laws, and

resolve a system flow rate by using a pump differential pressure function of P=f(Q,n) together with the system flow equation of C_v=Q/√

{square root over (P)} subsequently.

6. Apparatus according to claim 5, wherein the signal processor or processing module is configured to use the pump affinity laws denoted by the equations for pump flow, differential pressure and motor power, as follows:

Q/Q_max=n/n_max, P/P_max=(n/n_max)² and, w/w_max=(n/n_max)³, respectively.

7. Apparatus according to claim 6, wherein the signal processor or processing module is configured to derive the system flow rate, using a second order best-fit affinity pump curve function together with a system flow equation as follows:

8. Apparatus according to claim 7, wherein the signal processor or processing module is configured to use a pump differential pressure function of P=f(Q,n) in the form of Equation (2) as follows:

P(n,Q)=(α

Q²+b(n/n_max)¹Q+(n/n_max)²c).

9. Apparatus according to claim 8, wherein the signal processor or processing module is configured to reconstruct a motor power function at maximum speed with respect to the system coefficient by using a fitting or interpolating technique, and formulating the motor power at a given motor speed of w=w(C_v,n), by utilizing the pump affinity law.

10. Apparatus according to claim 9, wherein the signal processor or processing module is configured to use a second order best-fit affinity motor power function and express a system coefficient C_v in form of the Equation as follows:

11. Apparatus according to claim 10, wherein the signal processor or processing module is configured to express the motor power function at any instant speed, w=w(C_v,n), in form of the Equation as follows:

12. Apparatus according to claim 10, wherein the signal processor or processing module is configured to use a modified affinity law for motor power and speed representation in the form of the Equation as follows:

13. A method for pump differential pressure and flow monitoring, comprising:

receiving in a signal processor or processing module signaling containing information about motor readout values of power and speed, and also about pump and system characteristics equations together with empirical power equations that are constructed by a polynomial best-fit function together with pump affinity laws based upon a pump curve published by a pump manufacturer; and

determining in the signal processor or processing module corresponding signaling containing information about a pump or system pressure and a flow rate at the motor readout values of power and speed, based upon the signaling received.

14. A method according to claim 13, wherein the method further comprises resolving in the signal processor or processing module pump differential pressures and flow rate at an equilibrium point of the pump or system pressure at a motor steady state condition.

15. A method according to claim 13, wherein the method further comprises providing from the signal processor or processing module the corresponding signaling containing information about the pump or system pressure and the flow rate, including for pump differential pressure and flow monitoring.

16. A method according to claim 15, wherein the corresponding signaling contains information is used to control a hydronic pumping system.