Method for determining pump flow rates using motor torque measurements
First Claim
1. A method for determining an actual fluid flow rate of a fluid flowing through a pump without intruding into the fluid flow, the pump driven by a motor, the method comprising the steps of:
- obtaining a motor speed measurement value of the motor;
obtaining a motor torque measurement value of the motor;
determining a first fluid flow rate value for a known speed value above the motor speed measurement value corresponding to the motor torque measurement value;
determining a second fluid flow rate value for a known speed value lower than the motor speed measurement value corresponding to the motor torque measurement value; and
evaluating a proportional relation between the first and second fluid flow rate values to obtain the actual fluid flow rate.
1 Assignment
0 Petitions
Accused Products
Abstract
A method and system for determining fluid flow rates through a motor driven pump controlled by a variable speed drive is disclosed. The variable speed motor drive is used to characterize a pump fluid flow for a plurality of motor torque values at a plurality of known pump speeds. These characterized pump flow rate/torque values/speed are stored and used to determine a pump fluid flow at a measured pump speed and motor torque by interpolating between the known characterized fluid flow/torque/speed values. In another aspect of the invention, the pump flow rate at a measured torque, at a specified characterizing speed value is determined by interpolating between known characterizing pump flow rates. The determined pump flow rates can then be used to determine pump flow rates at a measured speed by interpolating between corresponding speed values which bound the measured speed.
-
Citations
19 Claims
-
1. A method for determining an actual fluid flow rate of a fluid flowing through a pump without intruding into the fluid flow, the pump driven by a motor, the method comprising the steps of:
-
obtaining a motor speed measurement value of the motor;
obtaining a motor torque measurement value of the motor;
determining a first fluid flow rate value for a known speed value above the motor speed measurement value corresponding to the motor torque measurement value;
determining a second fluid flow rate value for a known speed value lower than the motor speed measurement value corresponding to the motor torque measurement value; and
evaluating a proportional relation between the first and second fluid flow rate values to obtain the actual fluid flow rate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 12, 13, 14, 15, 16, 18)
-
-
10. A system for determining an actual fluid flow rate of a fluid flowing through a pump without intruding into the fluid flow, the pump driven by a motor, the system comprising:
-
means for obtaining a motor speed measurement value of the motor;
means for obtaining a motor torque measurement value of the motor;
means for determining a first fluid flow rate value for a known speed value above the motor speed measurement value corresponding to the motor torque measurement value;
means for determining a second fluid flow rate value for a known speed value lower than the motor speed measurement value corresponding to the motor torque measurement value; and
means for evaluating a proportional relation between the first and second fluid flow rate values to obtain the actual fluid flow rate. - View Dependent Claims (11, 17, 19)
a torque measurement device selected from the group consisting of resistive, photoelectric, strain gauge sensors.
-
-
17. The system as recited in claim 10 wherein said proportional relation is a linear relation.
-
19. The system as recited in claim 10, wherein the evaluating means includes means for interpolating between the first and second fluid flow rate values to obtain the actual fluid flow rate.
Specification