Screw Compressor Control Unit Prevents Motor Overload

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Solution Overview

Problem

Screw compressors in commercial vehicles experience short-term pressure peaks and increased drive load due to residual pressure after shutdown, leading to potential overloading of the electric motor when restarting, as compressed air flows back into the screw chamber.

Innovation Solution

Incorporating a control and regulation unit that prevents the screw compressor from restarting for a predetermined period, allowing a relief valve to reduce pressure to near-atmospheric levels, thereby avoiding the 'loading effect' and excessive starting current.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the screw compressor restarts immediately after shutdown, then the compressed air supply response time is improved, but the drive torque increases excessively causing motor overload

Engineering Contradiction:
Improveresponse timeVSAvoiddrive torque
Core Design Contradiction:
SpeedVSForce

Solution Approach 1:

The control unit implements a predetermined waiting period after shutdown before allowing restart. During this waiting phase, the relief valve reduces the pressure in the pressure holder to near-atmospheric levels, preventing the loading effect that would otherwise cause excessive drive torque and motor overload upon restart

Inventive Principle:
Principle #10Preliminary action

2Reliability

If a waiting phase is implemented before restart, then the loading effect is prevented, but the compressed air supply productivity decreases

Engineering Contradiction:
Improveloading effect preventionVSAvoidcompressed air supply
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system performs pressure reduction during the waiting phase before restart, ensuring that when the screw compressor重新启动, it operates under favorable pressure conditions. This preliminary pressure management prevents the loading effect while minimizing the impact on overall productivity

Inventive Principle:
Principle #10Preliminary action

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

Prevents the 'loading effect' by ensuring the screw compressor restarts from atmospheric pressure, reducing drive torque and preventing motor overload, ensuring safe and reliable operation.

Implementation Method 1

the pressure in the pressure holder can be reduced via the relief valve (80) to a pressure which is close to the atmospheric pressure or essentially corresponds to the atmospheric pressure

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP3516229B1Screw compressor for a utility vehicle
Publication Date: 2022.08.31 KNORR BREMSE SYSTEME FUER NUTZFAHIZEUGE GMBH
  • EP3516229B1 patent drawingFigure 1
  • EP3516229B1 patent drawingFigure 2

AI summary

The invention relates to a screw compressor system (100) for a utility vehicle, comprising at least one screw compressor (10) and at least one control and/or regulation unit (110) for controlling and regulating the screw compressor (10). Said control and/or regulation unit (110) is designed such that the screw compressor (10) is prevented, for a determined period of time, from re-starting after being stopped.