Dear Genevieve,
We have a somewhat different situation in that we use a Cryomech compressor and cold head in lieu of liquid nitrogen on our Bruker 7T/30 cm MRI magnet, but perhaps our data may still be useful to you. Our compressor receives cooling water through a Bruker heat exchanger which, in turn, is cooled using building chilled water with an automatic city water backup. Here are some typical operating conditions:
Primary loop (cools heat exchanger):
Building chilled water operation:
Supply temperature: 44 F (6.7 C)
Return temperature: 63 F (17.2 C)
Supply pressure: 110 psig
Return pressure: 90 psig
Flow rate: 4.9 GPM (18.5 lpm)
City water operation:
Supply temperature: 72 F (22.2 C)
Return temperature: 79 F (26.1 C)
Supply pressure: 30 psig
Return pressure: 0.3 psig (drains into sink)
Flow rate: 4.6 GPM (17.4 lpm)
Secondary loop (cools compressor):
Primary loop cooled with building chilled water:
Supply temperature: 58 F (14.4 C)
Return temperature: 68 F (20 C)
Supply pressure: 75.3 psig
Return pressure: 3.4 psig
Flow rate: 4.9 GPM (18.5 lpm)
Primary loop cooled with city water:
Supply temperature: 79 F (26.1 C)
Return temperature: 87 F (30.6 C)
Supply pressure: 74.7 psig
Return pressure: 3.2 psig
Flow rate: 4.9 GPM (18.5 lpm)
Please let me know if I can provide any additional information.
With best regards,
Ken.
Kenneth W. Fishbein, Ph.D.
Facility Manager, MRI Section
National Institute on Aging
National Institutes of Health
251 Bayview Boulevard
Suite 100, Room 04B120
Baltimore, MD 21224
(410) 558-8512
FAX: (410) 558-8376
kf31x_at_nih.gov<mailto:kf31x_at_nih.gov>
From: Genevieve Seabrook [mailto:gseabroo_at_uhnresearch.ca]
Sent: Friday, May 01, 2015 9:56 AM
To: ammrl_at_ammrl.org
Subject: AMMRL: differential pressure for cryoplatform compressor
Hi all,
I'm having a little bit of an issue with the water differential pressure and temperature of our 600MHz CryoPlatform compressor.
Everything was working fine with my 600MHz UNTIL while doing the renovations for my new 700MHz, someone noticed that the water line set-up for my 600 (installed 7 years ago) was not appropriate. And so, an expansion tank, a water feed and an air vent were installed. This is fine and makes sense since we are adding city water back-up. However, we now have a very low water pressure differential (15psi) and the return water temperature is too high (37degC).
At the moment, the supply water temperature is 15degC with a pressure of 59psi. The return water temperature is 37degC (used to be 30degC) with a pressure of 44psi. This gives me a differential pressure of 15psi which is too low (used to be 25psi). Apparently, the water flow is about 22L/min.
Any idea as why this would happen?
If people could email what they have as differential pressure and temperature, that would be great.
Thank you all,
Cheers,
Genevieve
*************************************************
Genevieve Seabrook PhD.
Scientific Associate
NMR Research & Facility Manager
UHN, Princess Margaret Cancer Centre
Division of Signaling Biology (OCI)
MaRS, Toronto Medical Discovery Tower
4th floor, Room 4-902
101 College Street
Toronto, ONT, M5G 1L7
Mobile: 416-629-7391
gseabroo_at_uhnresearch.ca<mailto:gseabroo_at_uhnresearch.ca>
http://nmr.uhnres.utoronto.ca/ikura/nmrsuite/nmrsuite.html
Received on Fri May 01 2015 - 08:20:36 MST