1. Exhaust to atmosphere G1 V1 V2 V3 LN2 Storage Vessel 150 l Dewar Cryostat Exhaust to atmosphere Nitrogen or helium gas bottle LN2 Circuit for MIT Test, September 2005 Flow Monitor

2. OperationV1V2V3G1 Fill CryostatOpen Closed Empty CryostatClosed Open Monitor remaining LN2 in cryostat OpenClosed Measuring the LN2 remaining in the cryostat after emptying. The flow monitor must integrate the flow over time as the cryostat gradually warms up to room temperature. The flow monitor is placed far away from the cryostat to ensure that the nitrogen gas has reached ambient temperature when it passes through the flow monitor - or a gas heater is inserted into the exhaust line.

3. Exhaust to atmosphere G1 V1 V2 V3 LN2 Storage Vessel 150 l Dewar Cryostat Exhaust to atmosphere Nitrogen or helium gas bottle LN2 Circuit for MIT Test, September 2005 Bursting discs and relief valves not shown V4 pressure gauge Flow Monitor