Oil-Cooled Screw Compressor Seal Gas Barrier

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Solution Overview

Problem

Oil-cooled screw compressors face issues with corrosive gases causing bearing degradation and high operational costs due to inefficient sealing and gas management systems, leading to increased power consumption and fluid leakage.

Innovation Solution

An oil-cooled screw compressor system with a separation gas supply system that uses a separation gas to prevent target gas from contacting the bearing lubricating fluid, combined with a control system to manage pressure and fluid flow, ensuring the separation gas is used efficiently and the bearing lubricating fluid is conserved.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a mechanical seal is used to seal the shaft in the seal chamber, then the target gas can be prevented from flowing into the bearing chamber, but the target gas may mix with the bearing lubricating fluid through the seal units, causing corrosion when the gas contains corrosive elements

Engineering Contradiction:

Improvesealing performanceVSAvoidcorrosion of bearing

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A buffer gas (nitrogen or inert gas) is introduced as an intermediary substance between the target gas and the bearing lubricating fluid. The buffer gas flows from the screw chamber through the first seal unit into the seal chamber, creating a protective gas barrier that prevents corrosive target gas from contacting the bearing lubricating fluid while maintaining effective sealing.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

An inert or non-corrosive gas atmosphere is created in the seal chamber by supplying buffer gas through the first seal unit. This inert atmosphere replaces the potentially corrosive target gas environment, protecting the bearing lubricating fluid from corrosion while maintaining sealing effectiveness.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Stress or pressure

If the target gas is supplied to the seal chamber to maintain pressure balance, then pressure equilibrium is achieved, but the corrosive target gas flows into the bearing chamber and degrades the bearing lubricating fluid

Engineering Contradiction:

Improvepressure balanceVSAvoidbearing lifespan

Core Design Contradiction:

Stress or pressureVSReliability

Solution Approach 1:

The seal chamber is filled with an inert or non-corrosive buffer gas instead of the corrosive target gas, while maintaining pressure balance with the screw chamber. This creates a protective atmosphere that prevents corrosion of the bearing lubricating fluid while achieving the necessary pressure equilibrium.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

A buffer gas acts as an intermediary substance between the target gas and the bearing lubricating fluid. The buffer gas maintains pressure balance with the target gas in the screw chamber while preventing direct contact between the corrosive target gas and the bearing lubricating fluid.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the separation gas supply pressure is increased to prevent target gas leakage, then sealing effectiveness is improved, but the consumption of separation gas increases operational costs

Engineering Contradiction:

Improvesealing effectivenessVSAvoidseparation gas consumption

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The pressure of the buffer gas supplied to the seal chamber is optimized to a specific range (higher than target gas pressure but controlled to avoid excessive consumption). This parameter optimization achieves effective sealing while minimizing buffer gas consumption and operational costs.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system monitors and controls the buffer gas supply pressure to maintain it within an optimal range that ensures sealing effectiveness while preventing excessive gas consumption. Pressure sensors and control mechanisms adjust the supply to match actual sealing needs.

Inventive Principle:

Principle #23Feedback

4Stress or pressure

If a pressure balancing path is provided to communicate the seal chamber with the screw chamber, then pressure equilibrium is maintained, but the target gas may flow through the pressure balancing path to the discharge side seal chamber

Engineering Contradiction:

Improvepressure equilibriumVSAvoidtarget gas contamination

Core Design Contradiction:

Stress or pressureVSObject-affected harmful factors

Solution Approach 1:

The pressure balancing path is designed to allow buffer gas to flow from the screw chamber through the first seal unit into the seal chamber, acting as an intermediary that maintains pressure equilibrium while preventing direct flow of target gas to the discharge side seal chamber.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP2896834B1Oil-cooled screw compressor system and oil-cooled screw compressor

Publication Date: 2017.10.25 MAYEKAWA MFG CO LTD

AI summary

In a housing 20 of an oil-cooled screw compressor 10, a separation gas supply path 59 through which separation gas is supplied to a separation gas supply gap 58 defined between a first seal unit and a second seal unit of a seal device 50, and a pressure balancing path 60 through which an area closer to a screw chamber 20a than the first seal unit in a discharge side seal chamber 20d communicates with a compression chamber at a pressure higher than an intake pressure and lower than a discharge pressure, are defined. A check valve 62 that restricts a flow of a fluid in a direction from the screw chamber 20a to the discharge side seal chamber 20d is disposed in the pressure balancing path 60.