LN2 circuit for MIT test - videoJune05 - PowerPoint PPT Presentation

Title: LN2 circuit for MIT test - videoJune05


1
Exhaust to atmosphere
LN2 Circuit for MIT Test, September 2005
LN2 Storage Vessel
V1
G1
Exhaust to atmosphere
Cryostat
V2
Nitrogen or helium gas bottle
V3
150 l Dewar
2
Operation V1 V2 V3 G1
Fill Cryostat Open Open Closed Closed
Empty Cryostat Closed Closed Open Open
Monitor remaining LN2 in cryostat Open Closed Closed Closed
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. Dear
Colleagues, Here are our thoughts on the
requirements for the MIT test this autumn. As I
see it the important thing is to measure the
amount of LN2 remaining in the cryostat after
blowing out the LN2 from the full cryostat,
because it is a safety issue. The attached scheme
shows the minimum equipment required. After
filling the cryostat the LN2 is blown out into
the temporary storage Dewar. Then the system is
sealed off allowing the boil off from the
cryostat to flow through a gas flow monitor to
atmosphere. A simple gas meter will do. The gas
will need to be warm since they measure volume
flow. I am pressing Cryonorm for a price for
their heater and if necessary we could use this.
The lines and valves do not need to be thermally
insulated and almost anything would do for the
test. Now a question for Peter Titus. Would you
be able to supply all the bits? If not, we will
have to discuss. Cheers, Roger Dr J. R. J. Bennett