Oil-Injected Screw Compressor Dual Cooling Control

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Solution Overview

Problem

Screw air compressors face inefficiencies in energy consumption due to challenges in maintaining optimal compressed air temperatures, leading to condensation of water vapor and reduced operational efficiency across varying environmental conditions.

Innovation Solution

An oil-injected screw air compressor with two oil cooling devices and a control unit dynamically adjusts the temperature of lubricating oil based on measured pressure, temperature, and humidity data to maintain compressed air temperatures above the dew point, ensuring isothermal compression conditions year-round.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single oil cooling device is used, then the structure is simple, but the temperature control precision is insufficient to prevent condensation under varying environmental conditions

Engineering Contradiction:
Improvetemperature control precisionVSAvoidcooling device structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The single oil cooling device is divided into two separate oil cooling devices, each independently controlling the temperature for different compression stages. This segmentation allows precise temperature control for each stage, preventing condensation under varying environmental conditions while maintaining manageable system complexity through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic temperature control by using sensors to detect environmental conditions and compressor operating parameters, then dynamically adjusting the cooling degree of each oil cooling device. This dynamic adjustment ensures the compressed air temperature remains above dew point across different environmental conditions, resolving the contradiction between control precision and system complexity

Inventive Principle:
Principle #15Dynamics

2Temperature

If aggressive cooling is applied to reduce oil temperature, then lubrication effectiveness improves, but compressed air temperature drops below dew point causing condensation

Engineering Contradiction:
Improvelubricating oil temperatureVSAvoidwater vapor condensation
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent applies different cooling degrees to different compression stages through separate oil cooling devices. The first oil cooling device provides stronger cooling for the high-temperature first stage compression, while the second oil cooling device provides milder cooling for the second stage. This localized differential cooling maintains lubrication effectiveness while preventing the compressed air temperature from dropping below dew point

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The control unit receives feedback from sensors monitoring environmental conditions, compressed air temperature, and oil temperature. Based on this feedback, the control unit dynamically adjusts the operation of each oil cooling device to maintain optimal temperatures, preventing both overheating and condensation. This closed-loop feedback system resolves the contradiction by continuously balancing cooling effectiveness with condensation prevention

Inventive Principle:
Principle #23Feedback

3Use of energy by moving object

If isothermal compression is maintained year-round, then energy efficiency improves, but the system becomes highly sensitive to environmental condition variations

Engineering Contradiction:
Improvecompressor energy consumptionVSAvoidenvironmental condition adaptability
Core Design Contradiction:
Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The patent implements a dynamic control system that continuously adapts to environmental conditions. Sensors detect temperature, humidity, and pressure variations, and the control unit adjusts the cooling degree of each oil cooling device in real-time. This dynamic adaptability maintains near-isothermal compression conditions for energy efficiency while automatically adjusting to seasonal and environmental variations, resolving the contradiction between energy efficiency and environmental adaptability

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3315780B2Oil-injected screw air compressor
Publication Date: 2021.11.24 ALMIG KOMPRESSOREN
  • EP3315780B2 patent drawingFigure 1

AI summary

An oil-injected screw air compressor (100) includes a first stage compression chamber (130), an air buffering chamber (140) coupled to the first stage compression chamber (130), a second stage compression chamber (150) coupled to the air buffering chamber (140), a first oil cooling device (230) for cooling lubricating oil for the first stage compression chamber (130) and the air buffering chamber (140), a second oil cooling device (430) for cooling lubricating oil for the second stage compression chamber (150) and the first oil cooling device (230), a plurality sensors (132, 142, 152) respectively located at the first stage compression chamber (130) outlet and the second stage compression chamber (150) outlet, and a control unit (300) respectively and dynamically controlling the first oil cooling device (230) and the second oil cooling device (430) according to preset pressure and temperature data measured by the sensors (132, 142, 152) or pressure and temperature data measured by the sensors (132, 142, 152), and temperature data and humidity data of an environment. The first oil cooling device (230) and the second oil cooling device (430) are connected in series.