Liquid Ring Pump Feedback Control for Cavitation Reduction

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Solution Overview

Problem

Cavitation is a significant cause of wear and failure in liquid ring pumps, particularly those operating at low-pressure/high-vacuum conditions, leading to reduced performance and reliability.

Innovation Solution

A control system comprising sensors and a controller to regulate the operation of a liquid ring pump, including a suction line, exhaust line, and operating liquid line, with feedback mechanisms to adjust motor speed based on sensor measurements to control temperature and pressure, thereby reducing the likelihood of cavitation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the liquid ring pump operates at low-pressure/high-vacuum conditions, then the pump achieves high vacuum performance, but cavitation occurs causing wear and failure

Engineering Contradiction:
Improvepump reliabilityVSAvoidcavitation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The control system continuously monitors pump operation parameters and adjusts the drive system in real-time based on sensor feedback, preventing cavitation conditions from developing while maintaining high vacuum performance

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts operational parameters such as drive speed and liquid ring level to optimize pump performance and prevent cavitation, allowing the pump to operate reliably at low-pressure/high-vacuum conditions

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the liquid ring pump operates without control, then the device complexity is low, but cavitation causes wear and reduced performance

Engineering Contradiction:
Improvepump reliabilityVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control system automatically monitors and adjusts pump operation without requiring external intervention, using sensors and automated control logic to prevent cavitation and maintain optimal performance

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system replaces manual monitoring and adjustment with automated electronic sensors and control circuits, reducing the need for mechanical intervention while improving reliability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system effectively minimizes cavitation, enhances pump performance, efficiency, and reliability, reduces operating liquid consumption, and lowers energy costs by maintaining optimal temperature and pressure conditions within the pump.

Implementation Method 1

When the drive system drives the shaft and the impeller, a liquid ring is formed on the inner wall of the chamber, thereby providing a seal that isolates individual volumes between adjacent impeller vanes

Methodology Applied
Scientific EffectLiquid ring formation:

Implementation Method 2

The impeller and shaft are positioned eccentrically to the liquid ring, which results in a cyclic variation of the volumes enclosed between adjacent vanes of the impeller and the liquid ring

Methodology Applied
Scientific EffectCyclic volume variation:

Implementation Method 3

Cavitation tends to be a significant cause of wear and failure in certain liquid ring pumps, especially those operating at a low-pressure/high-vacuum condition

Methodology Applied
Scientific EffectCavitation: Cavitation

Data Source

PatentEP3765741B1Control system for liquid ring pumps
Publication Date: 2026.03.11 EDWARDS TECH VACUUM ENG (QINGDAO) CO LTD
  • EP3765741B1 patent drawingFigure 1
  • EP3765741B1 patent drawingFigure 2
  • EP3765741B1 patent drawingFigure 3

AI summary

A control system comprising: a suction line (34); an exhaust line (38); an operating liquid line; a liquid ring pump (10) comprising a suction input coupled to the suction line (34), an exhaust output coupled to the exhaust line (38), and a liquid input coupled to the operating liquid line; a pump (16) configured to pump operating liquid into the liquid ring pump (10) via the operating liquid line and the liquid input; a motor (17) configured to drive the pump (16); a first sensor (24) configured to measure a first parameter, the first parameter being a parameter of an exhaust fluid of the liquid ring pump (10); a second sensor (22,32) configured to measure a second parameter, the second parameter being a parameter of a fluid received by the liquid ring pump (10); and a controller (20) operatively coupled to the first sensor (24), the second sensor (22,32), and the motor (17), and configured to control the motor (17) based on sensor measurements of the first sensor (24) and the second sensor (22,32). The control system advantageously tends to reduce or eliminate the wear caused by cavitations.