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Comparison of low-cost detection methods for liquid refrigerant flow at compressor inlet.

Number: 1294

Author(s) : LANGEBACH R., ANDJELKOVIC M., PFLIEHINGER T., PAL F. J.

Summary

Up to now, refrigerant compressors have been monitored in standard systems on the basis of continuous measurements of temperature, pressure, electrical variables and the oil level in the housing. Other measured variables are often not or only rarely taken into consideration due to comparatively high costs. These include, for example, mechanical vibrations or the vapor fraction in the suction line. In particular, the existence of liquid refrigerant in the suction line can be responsible for short-term damage as well as for continuous damage in the compressor over the long term. This includes liquid slugging as well as oil wash-out at important bearing points. Up to now, mainly capacitive sensors have been available for measuring the vapor fraction, which are only attractive in terms of price for very large refrigeration plants. In order to counter this situation in the future, three measurement methods for detecting liquid in the suction line of the compressor were investigated. These are optical detection by means of a camera and image recognition, optical detection of the light intensity when transilluminated by an LED, and the change in the natural frequency of a cantilever using a MEMS accelerometer. The results show that all three measurement methods are basically capable of reliably detecting of liquid refrigerant in the suction line at very low cost. The optical detection of the light intensity by transillumination with an LED has proven to be particularly suitable at best. In this case, the use of a standard inspection glass with few electronic components enables very good detection of the phase boundary and also filters out failure events, for example from machine oil passing the measurement section.

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Pages: 11 p.

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Details

  • Original title: Comparison of low-cost detection methods for liquid refrigerant flow at compressor inlet.
  • Record ID : 30030303
  • Languages: English
  • Subject: Technology
  • Source: 2022 Purdue Conferences. 26th International Compressor Engineering Conference at Purdue.
  • Publication date: 2022/07/15

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