Water-Injected Gas Compressor Water Mixing for Conductivity Control

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Solution Overview

Problem

Existing methods for controlling the water supply in water-injected gas compressors are inadequate in maintaining consistent conductivity and calcium carbonate content, leading to increased corrosion and sedimentation, which reduces compressor lifetime.

Innovation Solution

The method adjusts the proportions of demineralized and non-demineralized water based on locally available drinking water quality, eliminating the need for complex conductivity measurements in the cooling circuit, ensuring consistent conductivity and calcium carbonate levels in the cooling water.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cooling water is circulated in a closed circuit without additives, then the system operates as a quasi-closed system with constant water quantity, but the cooling water conductivity increases over time due to evaporation and absorption, leading to calcification and corrosion

Engineering Contradiction:
Improvecompressor operation stabilityVSAvoidcalcification and corrosion
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the chemical composition parameters of the cooling water by introducing a specific additive mixture containing phosphoric acid (0.5-5 ppm), polyphosphates (10-50 ppm), and silicates (10-50 ppm). This parameter change prevents calcification and corrosion while maintaining the closed circuit operation, resolving the contradiction between system stability and harmful effects.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention introduces chemical additives as intermediaries that mediate between the cooling water and the compressor components. These additives form protective films on metal surfaces and prevent calcium carbonate precipitation, thereby preventing calcification and corrosion without disrupting the closed circuit operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If complex conductivity measurements and control systems are implemented to maintain water quality, then water quality consistency is improved, but device complexity and cost increase significantly

Engineering Contradiction:
Improvewater quality consistencyVSAvoidmeasurement and control system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention applies preliminary action by pre-determining the optimal additive dosages based on expected operating conditions. The additives are introduced at fixed dosages (phosphoric acid: 0.5-5 ppm, polyphosphates: 10-50 ppm, silicates: 10-50 ppm) to proactively maintain water quality within target ranges, eliminating the need for complex real-time measurements and control systems.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention uses inexpensive chemical additives that can be easily dosed and mixed into the cooling water. These simple chemical substances provide continuous protection without requiring expensive sensors, controllers, or complex measurement systems, thereby maintaining water quality consistency while minimizing device complexity.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 provides cooling water with optimized conductivity and calcium carbonate content, effectively preventing calcification and corrosion, thereby extending compressor lifespan and maintaining consistent water quality.

Implementation Method 1

the mineral content of the cooling water decreases due to atmospheric humidity absorption, then this has a negative effect on the buffer capacity of the cooling water to absorb free carbonic acid

Methodology Applied
Scientific EffectBuffer capacity: Absorption (physical)

Implementation Method 2

Evaporation of cooling water causes the relative mineralization of the cooling water to increase, thereby increasing sediment

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP2811165B1Water-injected gas compressor and method for controlling the water supply
Publication Date: 2018.04.18 GARDNER DENVER DEUTLAND
  • EP2811165B1 patent drawingFigure 1

AI summary

The application relates to a method for controlling the water supply of a water-injected gas compressor which has a cooling water circuit into which is injected, as fresh water, demineralized water and non-demineralized water. The method according to the application comprises the following steps: determination of the electrical conductivity of the non- demineralized water; determination of a proportion of the demineralized water that must be added to the non-demineralized water, to provide a resulting mixture with a desired conductivity; addition of the specified proportion of demineralized water to the non-demineralized water and supplying the resulting mixture as the fresh water for the cooling water circuit; supply of the fresh water to the cooling water circuit in a desired amount. Further, the application relates to a Water-injected gas compressor comprising a compression stage, a cooling water circuit, and a water mixing unit.