Liquid Ring Pump Port Member Anti-Cavitation Design

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Solution Overview

Problem

Liquid ring pumps experience cavitation damage due to the sealing liquid, which existing solutions have not adequately addressed, leading to inefficiencies and potential mechanical failure.

Innovation Solution

The design incorporates an anti-cavitation passage and angled sealing liquid introduction channels to direct fluid flow, reducing pressure drops and cavitation by admitting high-pressure fluid into the bucket before discharge, thus minimizing the risk of cavitation damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sealing liquid is introduced into the buckets to ensure proper pump operation, then the liquid ring pump can maintain proper sealing and operation, but cavitation damage occurs at the base of the leading side of the trailing blade

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

Solution Approach 1:

The patent introduces sealing liquid into the buckets through a sealing liquid introduction port and channel before the buckets reach the discharge zone. This preliminary introduction ensures that the buckets are properly filled with sealing liquid to maintain operation reliability, preventing cavitation by ensuring proper liquid sealing in advance

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses a diverter structure as an intermediary element positioned near the sealing liquid introduction port. The diverter modifies the flow path of the sealing liquid, directing it to flow along the trailing blade surface in a controlled manner, which prevents direct high-velocity injection that would cause cavitation while still ensuring proper distribution of sealing liquid for reliable operation

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If material resistant to cavitation is used to reduce damage, then the pump components become more durable, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improvecomponent durabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of using special cavitation-resistant materials, the patent converts the harmful cavitation effect into a beneficial controlled flow pattern. By using the diverter to guide the sealing liquid flow along the blade surface, the patent creates a protective liquid film that prevents cavitation damage through proper flow management rather than material resistance, thereby avoiding increased manufacturing complexity

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Object-affected harmful factors

If diverters are added proximate the sealing liquid introduction port to reduce cavitation, then cavitation damage is reduced, but the device complexity increases

Engineering Contradiction:
Improvecavitation damageVSAvoidport member complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the diverter structure with the port member itself, making the diverter an integrated part of the port member rather than a separate component. This integration is achieved by providing a diverter surface or structure that is formed as part of the port member's geometry, thereby reducing the number of separate parts and simplifying manufacturing while still providing the cavitation protection function

Inventive Principle:
Principle #5Merging (Combining)

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 design effectively reduces cavitation damage by gradually increasing pressure within the bucket, preventing implosion and extending the lifespan of the pump components.

Implementation Method 1

admitting high-pressure fluid into the bucket before discharge, thus minimizing the risk of cavitation damage

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

The ring compresses the gas in the buckets because of its eccentric orientation. The orientation means the radially inward surface of the liquid ring has a much closer approach to the axis of the shaft in the radial direction along the compression zone

Methodology Applied
Scientific EffectEccentric compression: Eccentric

Implementation Method 3

The sealing liquid in the bucket can cause cavitation of the blades and in particular at the base of a leading side of a trailing blade forming the bucket

Methodology Applied
Scientific EffectCavitation: Cavitation

Data Source

PatentEP3256730B1A liquid ring pump port member having Anti-cavitation constructions
Publication Date: 2021.04.07 GARDNER DENVER NASH LLC
  • EP3256730B1 patent drawingFigure 1A
  • EP3256730B1 patent drawingFigure 1B~1C
  • EP3256730B1 patent drawingFigure 2~3

AI summary

A pump includes a housing that contains a liquid, and a rotor including a plurality of blades extending radially from a shaft, and defining a conical space. A port member is disposed within the conical space. The port member defines an inlet port in communication with a low pressure region, a discharge port in communication with a high pressure region, and an anti-cavitation port in communication with a fluid supply having a pressure between the low and the high pressure regions. Each pair of adjacent blades cooperates with the liquid and the port member to enclose a variable volume bucket, wherein rotation of the rotor selectively positions a bucket in an inlet position adjacent the inlet port to draw in fluid, in an anti-cavitation position wherein the bucket is adjacent the anti-cavitation port and fluid is admitted into the bucket, and a discharge position wherein the bucket is positioned adjacent the discharge port to discharge fluid.