NDTnet 1998 Aug, Vol.3 No.8

Abstract

Dynamic neutron radiography (DNR) has proved to be a useful method in visualization of inner working processes in various thermodynamic devices, especially in compression- and absorption-type refrigerators [1-3]. As far as DNR measurements are performed at research reactors, demand has arisen to combine the DNR visual observations with other methods [4], which can be used in the factory's quality control link system.

Vibration diagnostics is wide spread method in refrigerator industry. This method, however, can detect only the defective functioning - such as noise phenomena in compression-type refrigerators - but it can not discover the origin of malfunction. This is because of the small dimension of refrigerator boxes and due to their good sound conductivity.

We have performed combined DNR, vibration diagnostics (VD) and acoustic emission (AK) measurements to detect the origin of defective functioning in new constructions of compression-type refrigerators. Test of cooling units filled up with environment friendly R-134a freon cooling agent has been in the focus of our investigations. The main problem in these machines is, that the solvability of oil in the cooling agent is poor, which leads to the segregation of oil. By DNR measurements the reason of defective functioning is discovered by visualization the inner processes. By combined investigation of the visualized thermodynamic processes and simultaneous analysis of sound effects by VD and AE techniques, the results are adjusted to each other. On the basis of these observations development of a control method using AE for detection of defective refrigerators is under way.

References:
1. Balasko, M., Svab, E., Nedelik, "Neutron radiography investigations of absorption and compression refrigerators", Proc. 4th World Conf. on Neutron Radiography (Ed. J.P.Barton, Gordon and Breach Science Publ.) 1993, 31-38.

2. Parquet, du J., Bayon, G "Contribution of neutron radiography to the conservation of the environment", Proc. 4th WCNR, (Ed. J.P.Barton, Gordon and Breach Science Publ.) 1993, 65-72.

3. Asano, H "Application of neutron radiography to a diagnosis of refrigerator", Proc. 2nd Int. Topical Meeting on Neutron radiography System Design and Characterization (Eds. K.Mochiki and H.Kobayashi, RikkyoJ 1995, 392-397.

4. Balasko, M., Scab, E., Endroczi G "Combined dynamic neutron radiogpraphy and vibration diagnostics for industrial applications", Proc. 5th World Conference on Neutron Radiography, (Ed. Fischer et al, DGZfp, Berlin) 1997, 617-622.

Abstract Source:
Book of Abstracts, 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN: 87-986898-0-00

Full-Text Source:
Proceedings of the 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN:

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