Compressor Heat Detection in Fluid Machines Using Dynamic Thresholds

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Solution Overview

Problem

Existing fluid machines, such as gas compressors, fail to detect abnormal heat generation during low-pressure or high-speed operations, leading to delayed maintenance and potential damage.

Innovation Solution

Implementing a control system that adjusts threshold values for detecting abnormal heat generation based on frequency, pressure, current, and power, using temperature sensors and inverters to monitor and control compressor operation, allowing for early detection of abnormalities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a fixed upper limit temperature threshold is used for detecting abnormal heat generation, then the detection system is simple to implement, but abnormal heat generation cannot be detected during low-pressure or high-speed operations where temperature does not increase

Engineering Contradiction:
Improvedetection accuracy of abnormal heat generationVSAvoidcomplexity of control system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the temperature threshold dynamic rather than fixed. The threshold is adjusted based on operating conditions (pressure and frequency), allowing the detection system to adapt to different operational states. This resolves the contradiction by enabling accurate detection across varying conditions without requiring an overly complex multi-threshold system.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of temperature threshold based on other operating parameters (pressure and frequency). By establishing a relationship between these parameters, the system can determine appropriate thresholds dynamically. This approach improves detection accuracy while maintaining relatively simple control logic based on parameter interrelationships.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If temperature threshold is adjusted based on multiple parameters (pressure, frequency, current, power), then detection accuracy is improved, but the control system becomes more complex

Engineering Contradiction:
Improvedetection accuracy of abnormal heat generationVSAvoiddifficulty of monitoring multiple parameters
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies universality by using a single control system that handles multiple parameters (pressure, frequency, current, power) and performs both normal control functions and abnormality detection. This multi-functional approach improves detection accuracy while avoiding the need for separate complex monitoring systems for each parameter.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent implements feedback by continuously monitoring operating parameters and using them to dynamically adjust the temperature threshold. The control system receives feedback from sensors measuring pressure, frequency, current, and power, then adjusts detection thresholds accordingly. This feedback mechanism improves detection accuracy while keeping the system manageable through systematic parameter interrelationships.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3901461B1Fluid machine
Publication Date: 2025.07.09 HITACHI IND EQUIP SYST CO LTD
  • EP3901461B1 patent drawingFigure 1
  • EP3901461B1 patent drawingFigure 2(1)~2(2)
  • EP3901461B1 patent drawingFigure 3(1)~3(2)

AI summary

Even when abnormal heat generation occurs during operation in a state where the temperature of a compressor is not increased, abnormality cannot be detected. A fluid machine includes a fluid machine body; a motor that drives the fluid machine body; a temperature sensor that measures a temperature of the fluid machine body; and a control unit that controls the fluid machine body. The control unit changes a temperature threshold value based on at least one of a pressure of a fluid discharged by the fluid machine body and a frequency of a voltage input into the motor, and issues a notification when the temperature of the compressor body measured by the temperature sensor exceeds the temperature threshold value.