[labnetwork] N2 consumption by SRDs

[Paolini, Steven]

Nathan,
  Some, if not most SRD's have a N2 driven venturi that keeps the ferrofluidic rotor seal at some level of vacuum for when the seal ultimately fails. This is an effort to eliminate particles from contaminating the bowl when it occurs. The fix would be to switch the venturi feed to CDA which is quite less expensive but be careful that the N2 does not share the same feed as the bowl purge.
Interlocking the N2 with your lab software is a good way to reduce the N2 consumption but you must find a way to bleed some N2 into the bowl at idle. The N2 keeps the room's RH from clinging to the interior parts of the bowl which will drastically increase the time of rinsing to a resistance setpoint because of the water vapor in air not being deionized.
I hope this helps,
  Equipment Dood

Steve Paolini
Principal Equipment Engineer
Harvard University Center for Nanoscale Systems
11 Oxford St.
Cambridge, MA 02138
617- 496- 9816
spaolini at cns.fas.harvard.edu
www.cns.fas.harvard.edu

From: labnetwork <labnetwork-bounces at mtl.mit.edu> On Behalf Of Nathan Nelson - Fitzpatrick
Sent: Wednesday, April 05, 2023 2:47 PM
To: labnetwork at mtl.mit.edu
Subject: [labnetwork] N2 consumption by SRDs

Hi labnetwork,

My lab is going through a process of auditing our Nitrogen use, and an early target for saving on N2 are our spin rinse dryers.

We have four Sitek SRDs which are configured to continuously purge with N2 and to run occasionally (on a timer) to exercise the SRDs and run some DI water through them.  The constant N2 purge obviously consumes a ton of N2.

We're considering either:


  *   Purchasing an (expensive) valve from Sitek that would cut off N2 flow when the SRD controllers are off.  We would then leave the SRD controllers off when they are not enabled by our lab users.
  *   Or we might consider setting up an interlock to drive a solenoid valve that would cut off N2 flow to the SRDs when they are not enabled in our lab management software.

I'm wondering what other interesting solutions people have fashioned to reduce N2 consumption by SRDs?

I'm also curious if there are any pitfalls we should look out for when pursuing something like this?

Many thanks in advance,
  -Nathan

--
Nathan Nelson-Fitzpatrick  PhD, PEng   (He/Him)
Director, Quantum-Nano Fabrication and Characterization Facility (QNFCF)
Office of Research
University of Waterloo
200 University Avenue West, Waterloo, ON  N2L 3G1
P: 519-888-4567 ext. 31796
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