Compressor Damage Detection via Isentropic Model

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Solution Overview

Problem

Existing methods for monitoring compressors require complex instrumentation and evaluation logic, making them costly and difficult to install and maintain, while also being less effective in detecting damage within the compressor.

Innovation Solution

A method that calculates a comparison variable based on suction pressure, suction temperature, discharge pressure, and discharge temperature using a model of isentropic compression, including an isentropic exponent and a correction factor adjusted with measurement data, to determine the compressor's condition and detect potential damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If complex instrumentation and evaluation logic are used to monitor compressor damage, then measurement precision and reliability improve, but device complexity and cost increase

Engineering Contradiction:
Improvedetection accuracyVSAvoidinstrumentation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention extracts only the essential measurement variables (suction pressure, suction temperature, discharge pressure, discharge temperature) needed for damage detection, eliminating the need for complex vibration sensors and sophisticated evaluation logic on all compressor components. By focusing on these four key parameters, the system achieves reliable damage detection with minimal instrumentation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces complex mechanical vibration sensing systems with a thermodynamic model-based approach using pressure and temperature measurements. The damage detection is achieved through calculation of the comparison variable based on thermodynamic relationships, substituting mechanical measurement complexity with computational analysis of simpler thermal parameters.

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

2Reliability

If sensors are attached to all valves to be monitored, then reliability of damage detection improves, but device complexity and installation difficulty increase

Engineering Contradiction:
Improvedamage detection reliabilityVSAvoidsensor installation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention makes the four measurement variables (suction pressure, suction temperature, discharge pressure, discharge temperature) serve multiple functions: they simultaneously provide data for calculating the comparison variable, validating compressor performance, and detecting damage. This multi-functionality eliminates the need for separate sensors on each valve while maintaining reliable damage detection capability.

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

Solution Approach 2:

The invention introduces the comparison variable as an intermediary that mediates between the raw measurement data and the damage assessment. This comparison variable, calculated from the four measurement variables, serves as an intermediate representation that indicates compressor damage without requiring direct sensing of individual valve conditions, thereby simplifying the sensor installation while maintaining detection reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If complex evaluation logic is used to process measured signals, then measurement precision improves, but ease of operation and maintenance deteriorate

Engineering Contradiction:
Improvecondition assessment accuracyVSAvoidmaintenance simplicity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The invention uses a simple, readily available computational model (isentropic compression equations) that can be easily implemented and updated without requiring complex proprietary evaluation logic. The comparison variable calculation based on standard thermodynamic relationships provides accurate damage assessment while being simple to operate and maintain, as it relies on fundamental physical principles rather than complex algorithms.

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 method allows for reliable and early detection of compressor damage, such as wear or deposits, with minimal and inexpensive sensor requirements, enabling timely preventive measures and reducing unplanned downtime.

Implementation Method 1

Determination of a calculated end temperature (T2b), a calculated suction temperature (T1b), a calculated end pressure (p2b) or a calculated suction pressure (p1b) as a target value, which represents a good condition of the compressor, as a function of the measurement data from a maximum of three the measured variables (p1, T1, p2, T2)

Methodology Applied
Scientific EffectIsentropic compression: Adiabatic Heating

Data Source

PatentEP3983681B1Method for detecting damage to a compressor
Publication Date: 2023.08.09 BASF SE
  • EP3983681B1 patent drawingFigure 1
  • EP3983681B1 patent drawingFigure 2
  • EP3983681B1 patent drawingFigure 3

AI summary

The invention relates to a method for identifying damage on a compressor having an intake side and a discharge side, comprising the following steps: (i) detecting measurement data of the intake pressure (p1) and intake temperature (T1) measurement variables on the intake side, as well as end pressure (p2) and end temperature (T2) on the discharge side; (ii) determining a calculated end temperature (T2b), a calculated intake temperature (T1b), a calculated end pressure (p2b) or a calculated intake pressure (p1b) as a target variable, representing a good operating state of the compressor, as a function of the measurement data of max. three of the measurement variables (p1, T1, p2, T2); (iii) determining a comparison variable from at least one of the measurement variables (p1, T1, p2, T2) not used in step (ii); (iv) comparing the comparison variable and the target variable as a gauge of damage to the compressor; wherein the target variable determined in step (ii) is determined according to a model of the isentropic compression, taking into consideration the isentropic exponent (κ) of the gas to be compressed and a correction factor (η), and the correction factor (η) is adjusted on the basis of measurement data.