Screw Compressor Control Unit for Compression Ratio Adjustment

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Solution Overview

Problem

Compressor units with screw compressors require significant operational know-how due to complex functional relationships, making their integration into refrigeration systems cumbersome and requiring extensive system control implementation.

Innovation Solution

A compressor unit with an integrated compressor operating control unit that manages essential operational functions, including parameter acquisition, protection, and control, reducing the need for external system complexity by monitoring and controlling key parameters and ensuring safe operation within defined limits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the ability to influence final volume and initial volume is improved, then the adaptability of the screw compressor is improved, but the device complexity increases due to additional control mechanisms

Engineering Contradiction:
Improveability to influence final volume and initial volumeVSAvoidcontrol mechanisms
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The control unit automatically adjusts the slide channel position and valve opening based on sensor feedback about actual compression ratios, eliminating the need for manual intervention and complex external control systems while maintaining adaptability across different operating conditions

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Sensors monitor the actual compression ratio and provide feedback to the control unit, which then adjusts the slide channel position and valve timing to optimize performance, enabling adaptability through a closed-loop control system rather than complex open-loop mechanisms

Inventive Principle:
Principle #23Feedback

2Ease of operation

If manual adjustment of slide channel and control valve is simplified, then the ease of operation is improved, but the manufacturing precision requirements increase due to tighter tolerances needed for automatic control

Engineering Contradiction:
Improvemanual adjustment of slide channel and control valveVSAvoidtolerances
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

Manual mechanical adjustment of the slide channel and control valve is replaced with an automated control system that uses sensors and actuators to precisely position components, reducing the need for extremely tight manufacturing tolerances while improving ease of operation

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The control system dynamically adjusts operational parameters such as slide channel position, valve opening timing, and compressor speed to optimize performance across varying conditions, allowing the system to compensate for broader manufacturing tolerances through real-time parameter optimization

Inventive Principle:
Principle #35Parameter changes

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

Facilitates the installation and operation of refrigeration systems by simplifying the integration of screw compressors, enabling efficient monitoring and control without external units, thus reducing the complexity and cost of system integration.

Implementation Method 1

two screw rotors arranged in the screw rotor chamber and each rotatably mounted on the compressor housing about a screw rotor axis, the screw contours interlocking and each interacting with adjacent and partially surrounding compression wall surfaces, in order to receive gaseous medium supplied via a low-pressure chamber arranged in the compressor housing with an initial volume and to discharge it compressed to a final volume

Methodology Applied
Scientific EffectMechanical compression: Compression

Data Source

PatentEP4245997B1Compressor unit and method for operating a compressor unit
Publication Date: 2026.04.29 BITZER KUEHLMASCHINENBAU GMBH
  • EP4245997B1 patent drawingFigure 1
  • EP4245997B1 patent drawingFigure 2
  • EP4245997B1 patent drawingFigure 3

AI summary

A compressor unit comprising a screw compressor with a compressor housing, a screw rotor chamber arranged in the compressor housing, two screw rotors arranged in the screw rotor chamber and each rotatably mounted on the compressor housing about a screw rotor axis, the screw contours interlocking and each interacting with adjacent and partially surrounding compression wall surfaces, in order to receive gaseous medium supplied via a low-pressure chamber arranged in the compressor housing with an initial volume and to discharge it compressed to a final volume in the area of ​​a high-pressure chamber arranged in the compressor housing, and at least one control valve arranged in a slide channel of the compressor housing and adjacent to both screw rotors, which is movable in a displacement direction parallel to the screw rotor axes,and to improve the screw compressor's ability to influence the final volume and/or the initial volume in such a way that it can be used with as little functional know-how as possible regarding the functional relationships of the screw compressor, it is proposed that a compressor operating control unit be provided on the screw compressor, which is designed to perform at least one compressor operating function supporting the operation of the compressor unit.