Williamson Hall & Microkelvin Lab Cryogenics Systems Status.
Clearly not all of this information is for everyone, but I think at
one of the items applies to everyone. Please scan the topics for those
pertinent to you.
This is information that I believe is true and current. It is
intended to be policy or the final word of or for the Department
of Physics. I hope you find it useful.
Wiiliamson Hall is now the Geology Department.
The gaseous nitrogen line is set to approx. 5 psig in Williamson 30
in Microkelvin. It is available and can be used. There is a restriction
in the Williamson feed line that will cause the whole piping system to
drop to a lower pressure for everyone if there is too much demand. It
an intentional restriction for safety and to prevent the supply tank
being emptied if a line should break or if someone leaves a valve open.
You need to have someone in Cryogenic Services or your PI to train you
before you can do nitrogen fills. Please use the computer that
is set up for recording your liquid nitrogen
fills. It is near the fill port located inside the beige panel
next to Rm. 130.
We are now collecting all recovered gas at the NPB. Williamson has a
pressure gas transfer system. Recovered gas from Williamson,
and Chemistry is metered and collected into the same recovery balloon
it always has been. However, the high pressure recovery compressors
been replaced with low pressure ones. The new compressors
compress the gas just enough to send it down the pipe to the NPB. If
recovery rate at Williamson exceeds the rate at which it can be sent to
the NPB, the excess gas is further compressed and stored in the Room 30
gray pressure vessel bank and the white horizontal tanks until it can
be bled off
to the NPB. The whole system is automated and remotely monitored.
The dewar storage area (cage) in the hallway has been removed. The new
location has been set up in room 130. If at all possible dewars #15
16 should be stored in Microkelvin. The extra travel distances are
their toll on the dewar wheels. We have already replaced 6 castors that
have been damaged. Praxair 500s should be stored in Microkelvin or at
Williamson hallway port. Requests for helium should be by phone or e-mail
return unused dewars to a storage area as soon as you are done with
empty or not. The PSI liquefaction equipment is in the NPB.
We have a truck for transporting
dewars to and from Williamson and Microkelvin.
Vendor owned Gas Cylinder tanks:
A small collection of helium cylinders is set up in 130 for lab use.
any other gasses, please let me know what you need a few days before
need it. Please return empties to the same room but to the empties side
of the rack. Make sure all cylinders are secured with straps or chains
and that empty returned cylinders have their caps.
The exhaust fan for the Room 41 equipment has been replaced. A single
KVA RMG motor generator is on-line but is not fully operational for
labs. Two 35 KVA RMG motor generators are on-line and fully operational
A 70 KVA generator feeds Williamson and its UPS. A 125 KW diesel
feeds Microkelvin and its UPSs. PPD will be responsible for maintenance
and monitoring them. They are standby
generators. They only run after power is lost. There will be a 5-15
period when there is no power except from the UPS system when utility
goes out. Typically all generator supplied power is labeled in the lab
and comes from a single circuit breaker panel. The lab emergency
power is shared with the Microkelvin's emergency power systems (fire
elevator,...). The Williamson generator is strictly for the labs. Both
generators have a weekly, 20 minute preset runtime.
All WM and uK labs are now fed from a closed loop process water system
as of 6-6-02.
It is running at 60 psig supply - 18 psig return - 50F.
Stop here; this is next part is here for memory only, it is
We had big plans for changing the cooling water system to use
chilled water system in Williamson. However, our heat
aged to the point of being unusable due to leaks. The old
system for the tap water supply to the labs was failing due to age. We
replaced the old PVC filter manifold with a new copper
in order to expedite the installation we used flexible wire reinforced
PVC tubing to connect the existing plumbing to the new filter
This resulted in the very unfortunate situation that the tubing is able
to slip off of the hose barb fittings even though they are double
Additional clamping and connectors have been installed. The lab water
has failed again in two ways; It will not run reliably without shutting
down and heating the circulating water. The PVC piping is continuing to
fail and leak. The string filter cartridges in the basement of
are scheduled to be replaced every week on Tuesday mornings.
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