Hi,
I could suggest that you consider having your He compressors rebuilt on a
defined schedule, such as when they reach, for example, 50,000 hours. There
is one very good company that will rebuild the compressor for you, which we
have had done by them many times over the years. The company is called
Independence Cryogenics Engineering, inc. (ICE). The website is
https://weareice.com/.
They also sell refurbished He compressors at discounted prices. We have had
good luck with them. By rebuilding on a set schedule rather than replacing
compressors when they fail, you save money and almost certainly avoid the
issue you experienced. I think over time it is the cheapest solution. Since
you have several systems in operation, you might also consider buying a
refurbished compressor as a spare as we have done. Then you can swap that =
ne out when you send one of yours out for rebuilding and have only minimal
downtime required to connect the spare one to your system.
Best to you,
Greg
Gregory J. Heffron | Director, Biomolecular NMR Facility | Visiting Scientist, Dana-Farber Cancer Institute | Department of Cancer Biology Harvard Medical School 240 Longwood Ave. | Boston, MA 02115 | Fax :617-432-4383
[cid:831b2eb9-339f-452c-80bc-cc36ab43ee30]
________________________________
> From: main_at_ammrl.groups.io on behalf of Todd Rappe via groups.io
> Sent: Tuesday, July 29, 2025 3:29 PM
> To: main_at_ammrl.groups.io <main_at_ammrl.groups.io>
> Subject: Re: [AMMRL] Coolant for He Compressors
Our chilled water loop is similar to the one Alex describes at NMRFAM. It
had been problem-free for the past 14 years until this past winter we had a
catastrophic failure. Here's my cautionary tale. Over the Christmas holiday,
one of our helium compressors failed in a manner that leaked oil into our
chilled water lines. The contaminated chilled water ultimately caused the
failure of three other compressors on the loop. I will note that all the
compressors that failed all had over 100,000 hours so we knew that replacement
was somewhat imminent but we weren't expecting to have to replace them all
at the same time. Four "younger" compressors survived. We contracted with a
local company to service our chilled water system and clean out the oil.
Everything is back up and running now. The moral of this story: think about
your replacement schedule for helium compressors and there may be some value
in having each cryocooler on its own isolated cooling system (we still don't).
Also, I believe the initial compressor failure was caused by a corroded/clogged
quick-connect fitting on the chilled water input to the compressor. I've
replaced all of the Bruker-provided quick-connect fittings on our compressors
with wider diameter hose barbs to hopefully prevent such clogging in the future.
_____________________________________
Todd Rappe
Minnesota NMR Center <nmr.umn.edu>
612-625-9147 (office)
651-321-TODD (rings office and mobile)
612-624-8892 (magnet lab)
On Tue, Jul 29, 2025 at 1:52 PM Alex Paterson via groups.io wrote:
Hi Luke,
Re 2, is it possible for you to split the difference and have a heat exchanger
between your building chilled and your process loop? That’s how we do
it at NMRFAM.
Our process chilled water loop is closed and exclusively serves our equipment
(approx. 14 helium compressors). It has dedicated redundant lead-lag circulation
pumps. Physical Plant does periodic maintenance on the pumps and the loop itself.
The process chilled water loop rejects heat to the campus chilled water system
via a pair of heat exchangers.
It’s a non-trivial amount of space, but we’ve found this arrangement
to be highly effective. Keeping our process loop closed allows us to keep the working
fluid within helium compressor specifications (no algae!) while reducing the amount
and complexity of equipment we need to maintain.
Best,
Alex
Alex Paterson
The National Magnetic Resonance Facility at Madison (NMRFAM)
University of Wisconsin-Madison
alpaterson_at_wisc.edu<mailto:alpaterson_at_wisc.edu>
> From: main_at_ammrl.groups.io On Behalf Of Fulton, Luke via groups.io
> Sent: Tuesday, July 29, 2025 11:27 AM
> To: main_at_ammrl.groups.io<mailto:main_at_ammrl.groups.io>
> Subject: [AMMRL] Coolant for He Compressors
Hi all,
I'm planning end-of-life transition for our chilled water recirculator which
services two helium compressor cold heads. The main unit sits in a hallway
just outside the lab, and the building's design doesn't allow for putting
it anywhere else.
1) Any recommendations for vendor or chiller type? I'm also interested in
general quotes (feel free to message me privately with any insights on what
we might expect).
2) Some in my department are pushing for integrating into the chemistry building's
existing chilled water network. I've not heard of labs choosing this approach,
and my impression is endless complications from algae and other sundry building
issues. Anyone seen success with this? Or is it one of those 39-and-a-half-foot-pole topics?
Kind regards,
Luke
Luke Fulton, PhD
CHEM BLDG R003
NMR Core Facility Director
Unit 3060
COR2E & Department of Chemistry
55 N Eagleville Road
University of Connecticut
Storrs, CT 06279
email: fko24003_at_uconn.edu<mailto:fko24003_at_uconn.edu>
(alias): luke.fulton_at_uconn.edu<mailto:luke.fulton_at_uconn.edu>
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Received on Tue Jul 29 2025 - 17:49:19 MST