Cryogenic calibration facility for supercritical helium venturi flowmeter.

Abstract

Accurate flow measurement is essential in cryogenic field which is used for control, indication, alarm or commercial purposes. Because of good accuracy, simple structure and wide temperature range application, venturi flowmeters are selected to monitor supercritical helium flow rates at cooling loop of EAST (Experimental Advanced Superconducting Tokamak) superconducting magnets. In order to calibrate manufactured venturi flowmeters before application, a cryogenic calibration facility has been designed and constructed at CASIPP. The system of cryogenic calibration facility is comprised of cryostat, air-bath type vaporizer, standard flowmeter, cryogenic valve, helium refrigerator and data acquisition system. The maximum supercritical helium flow rate is 6g/s at about 5bara and 5K, which is available by a Linde LR280 helium refrigerator with a capacity of about 900W at 4.5K. This paper mainly presents the system of the cryogenic calibration facility and the first cool down with liquid nitrogen.