Williamson Hall & Microkelvin Lab Cryogenics Systems Status.

Clearly not all of this information is for everyone, but I think at least 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 not intended to be policy or the final word of or for the Department of Physics. I hope you find it useful.

Renovations:

Wiiliamson Hall is now the Geology Department.

Gaseous nitrogen:

The gaseous nitrogen line is set to approx. 5 psig in Williamson 30 psig 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 is an intentional restriction for safety and to prevent the supply tank from being emptied if a line should break or if someone leaves a valve open.

Liquid nitrogen:

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. 

Helium recovery:

We are now collecting all recovered gas at the NPB. Williamson has a low pressure gas transfer system. Recovered gas from Williamson, Microkelvin, and Chemistry is metered and collected into the same recovery balloon that it always has been. However, the high pressure recovery compressors have been replaced with low pressure ones. The new compressors compress the gas just enough to send it down the pipe to the NPB. If the 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.

Liquid helium:

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 taking 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 the Williamson hallway port. Requests for helium should be by phone or e-mail or web. Please return unused dewars to a storage area as soon as you are done with them, 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. For any other gasses, please let me know what you need a few days before you 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.

Uninterruptable power:

The exhaust fan for the Room 41 equipment has been replaced. A single 15 KVA RMG motor generator is on-line but is not fully operational for Williamson labs. Two 35 KVA RMG motor generators are on-line and fully operational for Microkelvin.

Generator power:

A 70 KVA generator feeds Williamson and its UPS. A 125 KW diesel generator 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 second period when there is no power except from the UPS system when utility power goes out. Typically all generator supplied power is labeled in the lab and comes from a single circuit breaker panel. The lab emergency generator power is shared with the Microkelvin's emergency power systems (fire systems, elevator,...). The Williamson generator is strictly for the labs. Both generators have a weekly, 20 minute preset runtime.

Water:

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 not the current situation.

We had big plans for changing the cooling water system to use the new chilled water system in Williamson.  However, our heat exchanger has aged to the point of being unusable due to leaks.  The old filtration 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 version.  However, in order to expedite the installation we used flexible wire reinforced PVC tubing to connect the existing plumbing to the new filter manifold.  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 clamped.  Additional clamping and connectors have been installed. The lab water chiller 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 Williamson are scheduled to be replaced every week on Tuesday mornings.



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Cryogenic Services at the University of Florida in the Department of Physics
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