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DOI: 10.5445/IR/1000078814
DOI: 10.1088/1757-899X/278/1/012169

Safety studies on vacuum insulated liquid helium cryostats

Weber, C; Henriques, A; Zoller, C; Grohmann, S

Abstract (englisch):
The loss of insulating vacuum is often considered as a reasonable foreseeable accident for the dimensioning of cryogenic safety relief devices (SRD). The cryogenic safety test facility PICARD was designed at KIT to investigate such events. In the course of first experiments, discharge instabilities of the spring loaded safety relief valve (SRV) occurred, the so-called chattering and pumping effects. These instabilities reduce the relief flow capacity, which leads to impermissible over-pressures in the system. The analysis of the process dynamics showed first indications for a smaller heat flux than the commonly assumed 4W/cm 2 . This results in an oversized discharge area for the reduced relief flow rate, which corresponds to the lower heat flux. This paper presents further experimental investigations on the venting of the insulating vacuum with atmospheric air under variation of the set pressure ( p set ) of the SRV. Based on dynamic process analysis, the results are discussed with focus on effective heat fluxes and operating characteristics of the spring-loaded SRV.

Zugehörige Institution(en) am KIT Institut für Technische Physik (ITEP)
Institut für Technische Thermodynamik und Kältetechnik (ITTK)
Publikationstyp Zeitschriftenaufsatz
Jahr 2017
Sprache Englisch
Identifikator URN: urn:nbn:de:swb:90-788149
KITopen ID: 1000078814
HGF-Programm 37.06.02; LK 01
Erschienen in IOP Conference Series: Materials Science and Engineering
Band 278
Seiten 012169
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