A mechanical temperature controller for liquid nitrogen cooling

✍ Scribed by A. Dupré

• Publisher: Elsevier Science
• Year: 1976
• Tongue: English
• Weight: 251 KB
• Volume: 16
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/0011-2275(76)90219-8

✦ Synopsis

Testing was carried out with different specimens and the following observations were made.

The specimen reached liquid nitrogen temperature in three minutes.

No frosting occured on the surface of the aluminium containers nor on the tensiometer grips. This is because the pressurized nitrogen gas prevents any air or moisture leaks in the system. In conventional cryostats for each test the system has to be evacuated which is a time consuming process. It was observed by the authors that the preparation time for this arrangement is less than five minutes.

After soldering the thermocouple, the specimen was slid into the grooves of the holders and liquid nitrogen was passed through. When the thermocouple recorded liquid nitrogen temperature, the tensile load was slowly applied. The results obtained for various specimens were found to be satisfactory. Consistency was also checked by testing a number of specimens of the same material. The total duration of the test would normally be ten minutes.

Conclusion

The simplicity and reliability of this set-up encourage the authors to hope it will be widely used in various research laboratories. This work has been carried out only at liquid nitrogen temperature. The authors propose that the same cryostat could be developed to test specimens at temperatures above liquid nitrogen by incorporating a heater into the specimen.