IR Sensor Temperature Correction via Reference Heating

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Solution Overview

Problem

Existing IR sensor systems in vacuum pumps, such as turbomolecular pumps, face reliability and accuracy issues due to contamination and environmental influences, leading to incorrect temperature measurements, which can cause operational defects and reduce the efficiency of rotating machines.

Innovation Solution

A method that involves measuring a first temperature using an IR sensor and comparing it to a reference temperature generated by a heat source, allowing for correction of the measured value if deviations occur, thereby compensating for sensor impairments and ensuring accurate temperature determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an IR sensor is used for continuous temperature monitoring during operation, then non-contact temperature measurement is achieved, but the sensor becomes subject to contamination and functional impairment leading to incorrect measurements

Engineering Contradiction:
Improvetemperature measurement accuracyVSAvoidsensor functional reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system uses a reference temperature measurement path that provides continuous feedback about the IR sensor's actual performance. The control unit compares the reference temperature measured by the IR sensor against the known actual reference temperature, detects deviations caused by contamination, and uses this feedback to correct the measurement location temperature readings, thereby maintaining measurement accuracy despite sensor degradation

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

A reference temperature source (heating element) is introduced as an intermediary standard between the IR sensor and the measurement location. This reference source provides a known, controllable temperature that acts as a mediator to calibrate and correct the IR sensor's measurements indirectly, allowing the sensor to compensate for its own contamination without direct contact with the process being measured

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the IR sensor is repeatedly calibrated using a blackbody radiator, then sensor deterioration is compensated, but the device complexity and calibration requirements increase

Engineering Contradiction:
Improvetemperature measurement accuracyVSAvoidcalibration system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The calibration function is extracted from an external blackbody radiator and integrated directly into the vacuum pump system through a compact heating element that serves as an on-board reference temperature source. This eliminates the need for external calibration equipment and simplifies the overall system while maintaining measurement accuracy

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system performs self-calibration by using its own integrated heating element as a reference source. The IR sensor measures the known temperature of the heating element, automatically detects its own drift or contamination, and corrects subsequent measurements without requiring external intervention or complex external calibration equipment

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If temperature-dependent expansion of components is allowed beyond certain levels, then operational flexibility is maintained, but defects occur reducing reliability

Engineering Contradiction:
Improveoperational flexibilityVSAvoidcomponent defect prevention
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The control unit continuously monitors the corrected temperature at the measurement location and provides feedback about the actual thermal state of rotating components. This enables real-time detection of temperature trends that could lead to excessive expansion, allowing operational adjustments before defects occur, thus maintaining both flexibility and reliability

Inventive Principle:
Principle #23Feedback

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 approach enhances the operational reliability of temperature-sensitive devices by correcting erroneous readings and preventing defects, thus improving the overall efficiency and maintenance economy of vacuum pumps.

Implementation Method 1

an infrared (IR) sensor system integrated in a vacuum pump... a first temperature Tobs,1 is measured at a measurement location... a second temperature Tobs,2 is measured at the reference location

Methodology Applied
Scientific EffectInfrared radiation detection: Infrared Radiation

Implementation Method 2

The heat source for generating the reference temperature Tref at the reference location can include a heating element, in particular a controllable heating element. For example, a resistance heater can be used.

Methodology Applied
Scientific EffectResistive heating: Joule Heating

Data Source

PatentEP3636933B1Method for determining a temperature using an infrared sensor
Publication Date: 2021.11.03 PFEIFFER VACUUM GMBH
  • EP3636933B1 patent drawingFigure 1
  • EP3636933B1 patent drawingFigure 2
  • EP3636933B1 patent drawingFigure 3

AI summary

The present invention relates to a method for determining a temperature using an IR sensor system, for example a vacuum pump, in particular a turbomolecular pump, in which a first temperature Tobs,1 is measured at a measuring location, a reference temperature Tref is generated by a heat source at a reference location, a second temperature Tobs,2 is measured at the reference location, the second temperature Tobs,2 is compared with an expected temperature Texp resulting from the reference temperature Tref, and if the second temperature Tobs,2 deviates from the expected temperature Texp, the first temperature Tobs,1 is corrected on the basis of the deviation.