Liquid Ring Pump Mechanical Seal Lubrication via Outlet Chamber Extension

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Solution Overview

Problem

Mechanical seals in liquid ring pumps, particularly in vacuum sewage systems, face high risks of damage due to dry conditions and turbulence, leading to reduced reliability and lifespan.

Innovation Solution

The mechanical seal is positioned within an enlarged outlet chamber with an integrated extension, ensuring a steady flow of sewage water for lubrication, and additional features like axial or radial vanes and flange means are used to direct and retain the sewage flow for enhanced lubrication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the mechanical seal is positioned in a standard outlet chamber, then the pump structure is simple, but the mechanical seal is subject to dry conditions and high risks of damage

Engineering Contradiction:
Improvemechanical seal reliabilityVSAvoidoutlet chamber structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The outlet chamber is extended axially along the drive shaft, creating an elongated space that allows the mechanical seal to be positioned within a region where sewage flow naturally provides lubrication. This dimensional extension transforms the seal's operating environment from dry to lubricated without adding external lubrication systems.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The sewage flow itself serves as the lubricant for the mechanical seal. By positioning the seal within the extended outlet chamber, the system uses the pumped medium (sewage water) to automatically lubricate the seal, eliminating the need for separate lubrication systems or external interventions.

Inventive Principle:
Principle #25Self-service

2Duration of action of moving object

If the outlet chamber is enlarged with an integrated extension, then sewage water flow is retained for lubrication, but the pump housing volume increases

Engineering Contradiction:
Improvemechanical seal lifespanVSAvoidoutlet chamber volume
Core Design Contradiction:
Duration of action of moving objectVSVolume of stationary object

Solution Approach 1:

The extension of the outlet chamber is integrated directly into the pump housing structure, merging the lubrication chamber with the existing outlet chamber. This combination allows the sewage flow to be retained and directed toward the mechanical seal without requiring a separate lubrication system or additional external components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Rather than increasing the radial or axial width of the outlet chamber, the design extends the chamber along the drive shaft dimension. This directional extension provides the necessary volume for lubrication while minimizing overall pump size increases by utilizing the existing structural orientation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If axial or radial vanes are added to direct sewage flow toward the mechanical seal, then lubrication is enhanced, but device complexity increases

Engineering Contradiction:
Improvemechanical seal lubricationVSAvoidoutlet chamber components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The vanes are positioned specifically within the extended outlet chamber region, creating localized flow direction only where needed near the mechanical seal. This localized flow control ensures lubrication at the critical seal interface without requiring complex flow management throughout the entire pump housing.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The vanes utilize the kinetic energy and flow dynamics of the sewage itself to direct the liquid toward the mechanical seal. Rather than requiring powered actuators or complex control systems, the hydraulic action of the flowing sewage is harnessed to achieve the desired flow direction and lubrication.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 arrangement significantly extends the mechanical seal's lifespan by maintaining consistent lubrication, improving the pump's reliability and operational efficiency in turbulent sewage environments.

Implementation Method 1

the mechanical seal is arranged to be lubricated by the flow of sewage, i.e. sewage water

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP2558727B2Liquid ring pump and method for operating a liquid ring pump
Publication Date: 2022.08.10 EVAC OY
  • EP2558727B2 patent drawingFigure 1
  • EP2558727B2 patent drawingFigure 2
  • EP2558727B2 patent drawingFigure 3

AI summary

The invention relates to a liquid ring pump (1) for generating vacuum and for pumping a flow of sewage in a vacuum sewage system. The liquid ring pump comprises in the direction of the flow of sewage a pump inlet (11), an inlet chamber (13), a pump housing (14) provided with a rotor (15) arranged on a drive shaft(16) provided with a mechanical seal (20), an outlet chamber(17), and an pump outlet (19). The mechanical seal (20) is arranged within the outlet chamber (17). The outlet chamber (17) is provided with an integrated extension (18) providing an enlargement of the outlet chamber (17)in order to retain the flow of sewage in the outlet chamber (17) before it is discharged from the pump outlet (19) in order to improve the lubrication of the mechanical seal (20).