Liquid ring pump control

Patent metadata

Field	Value
Publication number	US-11619232-B2
Application number	US-201916977770-A
Country	US
Kind code	B2
Filing date	Mar 14, 2019
Priority date	Mar 14, 2018
Publication date	Apr 4, 2023
Grant date	Apr 4, 2023

Abstract

A control system comprising: a suction line; an exhaust line; an operating liquid line; a liquid ring pump comprising a suction input coupled to the suction line, an exhaust output coupled to the exhaust line, and a liquid input coupled to the operating liquid line; a motor configured to drive the liquid ring pump; a first sensor configured to measure a first parameter of an exhaust fluid of the liquid ring pump; a second sensor configured to measure a second parameter of a gas being received by the liquid ring pump via the suction line; and a controller operatively coupled to the first sensor, the second sensor, and the motor, and configured to control the motor based on sensor measurements of the first sensor and the second sensor.

First claim

The invention claimed is:

1. A system comprising:
a suction line;
an exhaust line;
an operating liquid line;
a liquid ring pump comprising a suction input coupled to the suction line, an exhaust output coupled to the exhaust line, and a liquid input coupled to the operating liquid line;
a motor configured to drive the liquid ring pump;
a first sensor configured to measure a first parameter, the first parameter being a parameter of an exhaust fluid of the liquid ring pump;
a second sensor configured to measure a second parameter, the second parameter being a parameter of a gas being received by the liquid ring pump via the suction line; and
a controller operatively coupled to the first sensor, the second sensor, and the motor, and configured to:
calculate a vapor pressure of an operating liquid based on the equation:

P
wv

=

A
*

10

(

m
*

T
1

T
1

+

T
n

)

where A is a constant, m is a constant, T n is a constant, and T 1 is the first parameter; and
control the motor based on a function of the second parameter and the vapor pressure of the operating liquid.

2. The system according to claim 1 , wherein the first parameter is a temperature.

3. The system according to claim 1 , wherein the second parameter is a pressure.

4. The system according to claim 1 , wherein the function of the second parameter and the vapor pressure of the operating liquid is:
Δ P=P 1 −P

where P 1 is the second parameter, and
P=P wv +P offset

where P wv is the vapor pressure of the operating liquid and P offset is an offset value.

5. The system according to claim 1 , wherein the controller is configured to determine an operating speed for the motor based on sensor measurements of the first sensor and the second sensor, and to control the motor in accordance with the determined operating speed.

6. The system according to claim 1 , wherein the controller is a controller selected from the group of controllers consisting of a proportional controller, an integral controller, a derivative controller, a proportional-integral controller, a proportional—integral—derivative controller, a proportional—derivative controller, and a fuzzy logic controller.

7. The system according to claim 1 , further comprising an operating liquid recycling system configured to recycle operating liquid in the exhaust fluid of the liquid ring pump back into the liquid ring pump.

8. The system according to claim 7 , wherein the operating liquid recycling system comprises a separator configured to separate operating liquid from the exhaust fluid of the liquid ring pump.

9. The system according to claim 7 , wherein the operating liquid recycling system comprises a cooling means configured to cool the recycled operating liquid prior to the recycled operating liquid being received by the liquid ring pump.

10. The system according to claim 1 , further comprising a non-return valve disposed on the suction line and configured to permit fluid flow into the liquid ring pump and to oppose fluid flow out of the liquid ring pump.

11. The system according to claim 1 , further comprising a spray nozzle disposed on the suction line and configured to receive operating fluid and to spray the received operating fluid into the suction line.

12. The system according to claim 1 , further comprising:
one or more regulating devices configured to control flow of the operating liquid into the liquid ring pump; and
a third sensor configured to measure a third parameter, the third parameter being a parameter of an operating liquid received by the liquid ring pump via the operating liquid line; wherein
the controller is further operatively coupled to the third sensor and the one or more regulating devices and configured to control the one or more regulating devices based on sensor measurements of the first sensor and the third sensor.

13. A method for controlling a system, the system comprising: a suction line; an exhaust line; an operating liquid line; a liquid ring pump comprising a suction input coupled to the suction line, an exhaust output coupled to the exhaust line, and a liquid input coupled to the operating liquid line; and a motor configured to drive the liquid ring pump; the method comprising:
measuring, by a first sensor, a first parameter, the first parameter being a parameter of an exhaust fluid of the liquid ring pump;
measuring, by a second sensor, a second parameter, the second parameter being a parameter of a gas being received by the liquid ring pump via the suction line;
calculating, by a controller operatively coupled to the first sensor, the second sensor, and the motor, a vapor pressure of an operating liquid based on the equation:

P
wv

=

A
*

10

(

m
*

T
1

T
1

+

T
n

)

where A is a constant, m is a constant, T n is a constant, and T 1 is the first parameter; and
controlling, by the controller based on based on a function of the second parameter and the vapor pressure of the operating liquid, the motor.

14. The method according to claim 13 , further comprising:
recycling the operating liquid in the exhaust fluid of the liquid ring pump back into the liquid ring pump using an operating liquid recycling system.

15. The method according to claim 13 , further comprising:
determining, by the controller, an operating speed for the motor based on sensor measurements of the first sensor and the second sensor; and
controlling the motor in accordance with the determined operating speed.

Assignees

• Edwards Tech Vacuum Engineering Qingdao Co Ltd
• Edwards Ltd

Inventors

• COECKELBERGS Joeri
• Glaister Mark Gordon
• De Bock Andries Daniel Jozef

Classifications

• F04C2270/18

  Pressure · CPC title

• F04C2270/19

  Temperature · CPC title

• F04C2270/40

  Conditions across a pump or machine · CPC title

• F04C2210/22

  gaseous, i.e. compressible · CPC title

• F04C2240/81

  Sensor, e.g. electronic sensor for control or monitoring · CPC title