Liquid Ring Vacuum Pump Cavitation Regulation via Vibration Monitoring

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Solution Overview

Problem

Liquid ring vacuum pumps face inefficiencies due to the need to maintain a safe distance from cavitation limits to prevent damage, which limits their performance capacity, and existing speed control methods are inadequate for addressing different types of cavitation.

Innovation Solution

The method involves recording and comparing vibration and liquid content measurements with predetermined thresholds to adjust pump speed, increasing speed when liquid content is high and decreasing it when low, to effectively manage cavitation and optimize performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the pump operates close to cavitation limits to maximize performance capacity, then productivity is improved, but reliability deteriorates due to mechanical damage from cavitation

Engineering Contradiction:
Improveperformance capacityVSAvoidpump durability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system continuously monitors vibration levels and liquid content, comparing them against threshold values to detect cavitation conditions. Based on this feedback, the control unit automatically adjusts pump speed to prevent cavitation damage while maximizing performance capacity utilization

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The pump speed is dynamically adjusted based on real-time operating conditions rather than maintaining a fixed safe distance from cavitation limits. The system adapts speed continuously to operate near cavitation thresholds when conditions permit, thereby maximizing productivity while preventing damage

Inventive Principle:
Principle #15Dynamics

2Reliability

If the pump speed is reduced to prevent cavitation, then reliability is improved, but productivity deteriorates due to underutilization of pump capacity

Engineering Contradiction:
Improvecavitation preventionVSAvoidperformance capacity utilization
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system changes the operating parameters (speed) dynamically based on detected cavitation conditions and liquid content. When cavitation is detected and liquid content is low, speed is reduced to prevent damage. When liquid content is high, speed is increased to pump out excess liquid, thereby maintaining both reliability and productivity

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the pump speed is increased to pump out excess liquid, then reliability is improved by eliminating cavitation caused by high liquid content, but energy consumption increases

Engineering Contradiction:
Improvecavitation eliminationVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system applies periodic speed adjustments rather than continuous high-speed operation. Speed is increased temporarily when cavitation is detected with high liquid content to pump out the excess liquid, then reduced when conditions normalize, thereby eliminating cavitation while minimizing energy consumption

Inventive Principle:
Principle #19Periodic action

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

This approach allows for automatic adjustment of pump operation to handle various cavitation types, enhancing efficiency by utilizing the pump's capacity while preventing damage, and can reduce energy consumption by operating close to cavitation limits.

Implementation Method 1

measured vibration values of the pump are recorded and compared with a predetermined cavitation threshold value

Methodology Applied
Scientific EffectVibration detection: Vibration

Data Source

PatentEP2791511B1Liquid ring vacuum pump with cavitation regulation
Publication Date: 2016.09.14 STERLING IND CONSULT GMBH
  • EP2791511B1 patent drawingFigure 1~2
  • EP2791511B1 patent drawingFigure 3~4
  • EP2791511B1 patent drawingFigure 5A~5C

AI summary

The invention relates to a method for operating a liquid ring vacuum pump in which vibration measurements of the pump are taken and compared with a prescribed cavitation threshold (26). In addition, a measurement representing the liquid content in the gas to be conveyed is taken. This measurement is compared with a prescribed threshold. The rotational speed of the liquid ring vacuum pump is reduced if the prescribed cavitation threshold (26) has been exceeded and the liquid content is less than the prescribed threshold. The rotational speed is increased if the prescribed cavitation threshold has been exceeded and the liquid content is greater than the prescribed threshold. The invention also relates to a liquid ring vacuum pump designed for implementing the method. Due to the regulation depending on the oscillations of the pump in accordance with the invention, the pump can be operated near the cavitation boundary without any risk of damage.