Sealing Baffle Axial Load Balance for Single Screw Compressors

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Solution Overview

Problem

Single screw compressors face significant axial load increases at high suction pressures, leading to reduced bearing life and frequent maintenance needs due to increased load on the main shaft bearings.

Innovation Solution

A high suction pressure load balance assembly featuring a sealing baffle keyed to the main rotor drive shaft, utilizing pressurized oil to counteract the axial force, thereby reducing the load on shaft bearings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high suction pressure operation is implemented, then compressor productivity is improved, but axial load on main shaft increases dramatically

Engineering Contradiction:
Improvecompressor productivityVSAvoidaxial load on main shaft
Core Design Contradiction:
ProductivityVSForce

Solution Approach 1:

The patent applies the counterweight principle by introducing a balance shaft with counterweights that rotate in opposition to the main shaft. The counterweights are positioned and sized to generate centrifugal forces that counterbalance the axial thrust forces generated during high suction pressure compression, thereby reducing the net axial load on the main shaft bearings while maintaining high productivity operation

Inventive Principle:
Principle #8Anti-weight (Counterweight)

2Productivity

If high suction pressure operation is implemented, then compressor productivity is improved, but bearing life decreases dramatically

Engineering Contradiction:
Improvecompressor productivityVSAvoidbearing life
Core Design Contradiction:
ProductivityVSDuration of action of stationary object

Solution Approach 1:

The balance shaft with strategically positioned counterweights reduces the axial thrust load on main shaft bearings by generating opposing centrifugal forces during high suction pressure operation, thereby extending bearing life while maintaining high productivity

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The patent employs preliminary cushioning by introducing axial clearance between the main shaft and bearings, and using elastomeric elements and oil film lubrication to cushion and distribute the remaining axial loads before they reach the bearings, preventing premature wear and extending bearing life during high pressure operation

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Duration of action of stationary object

If bearings are added to distribute load, then bearing life is improved, but device complexity increases

Engineering Contradiction:
Improvebearing lifeVSAvoiddevice complexity
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The patent segments the load-bearing function by introducing multiple support elements including axial clearances, elastomeric cushioning elements, and oil film lubrication zones along the main shaft, distributing the axial load across multiple locations and mechanisms rather than relying on a single bearing system, thereby extending bearing life without significantly increasing overall device complexity

Inventive Principle:
Principle #1Segmentation

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 solution effectively balances the axial force during high suction pressure conditions, extending the lifespan of bearings and reducing maintenance needs by distributing the load more evenly.

Implementation Method 1

using the pressurized oil used to lubricate the mechanical shaft seal of the compressor

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 2

the pressurized oil used to lubricate the mechanical shaft seal

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP3513077B1High suction pressure single screw compressor with thrust balancing load using shaft seal pressure and related method
Publication Date: 2023.12.27 COPELAND IND LP
  • EP3513077B1 patent drawingFigure 1
  • EP3513077B1 patent drawingFigure 2
  • EP3513077B1 patent drawingFigure 3

AI summary

A high suction pressure thrust load balance assembly configured for use with a single screw compressor includes comprises a sealing baffle that is keyed to, so as to be rotatable along with, a main rotor drive shaft of the single screw compressor. The sealing baffle is configured to create a force or load to counteract the axial force of the main rotor drive shaft created during rotation of the main rotor drive shaft using the pressurized oil used to lubricate the mechanical shaft seal of the compressor.