[Sneap] Fast closing gate-valves

[Chris Westerfeldt]

Greetings Ovidiu,
    We have used three types of ³fast² valves here at TUNL.  The least
expensive one was just a NC Solenoid valve with KF25 flanges
that we purchased from one of the standard suppliers.  It was not as fast as
the ones sold by NEC or VAT but closed in well under a second.
I cannot recall if it was Key High Vacuum, Vacoa or whom...

The second type that we have (no longer used) is a locomotive valve.  It has
a 4² bore and is spring loaded.  Air pressure is used to open and cock the
mechanism, a pressure sensor upstream triggers a vacuum tube controller (
that we have given up on) to release the valve.  I don¹t recall the
specifications but it was in the tens of  milliseconds.

    The third valve I know very little about.  It is homemade from a LANL
design I believe.  It uses a high voltage capacitor bank
and coil to drive a wedge shaped plug into the valve when triggered ­ sort
of like a rail gun.  I may be able to find some information on this
in the archives ­ last used in the late 70¹s here, still installed though.
It is on a 2² Dependex beamline as I recall.
- Chris
-- 

Chris R. Westerfeldt
Research Scientist / T.U.N.L. Radiation Safety Manager
Duke University Physics Department &
Triangle Universities Nuclear Laboratory
Science Drive, Box 90308
Durham, NC  27708-0308
Tel: (919) 660-2600
Fax: (919) 660-2634
Email: Cwest at Tunl.Duke.Edu



From: "Toader, Ovidiu" <ovidiu at umich.edu>
Reply-To: Symposium of Northeastern Accelerator Personnel
<sneap at tunl.duke.edu>
Date: Thu, 12 Jun 2008 16:52:23 -0400
To: Symposium of Northeastern Accelerator Personnel <sneap at tunl.duke.edu>
Conversation: Fast closing gate-valves
Subject: [Sneap] Fast closing gate-valves

The host for the 2008 SNEAP annual meeting is the University of Michigan at
Ann Arbor.  The meeting dates are: October: 12 - 17, 2008.
The meeting web link is:
http://www-ners.engin.umich.edu/research/Mibl/Sneap/2008.htm


Greetings!
 
We are looking into an application that would require some very fast closing
gate-valves in case of component / end station failure on our beamline. We
would be irradiating a thin membrane and have water on the other side of the
vacuum.  Upon failure of the membrane, it would be critical to isolate the
beamline components in the shortest amount of time possible.
 
Do any of you have such valves on your system?  If yes can you let me know
if they work as advertised, what experiences you had with them and maybe
recommend a manufacturer?  Any idea of the prices (what I got so far is
nothing short of astronomical)?
 
Thank you,
 
Ovidiu
University of Michigan
ovidiu at umich.edu


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