40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  40m Log  Not logged in ELOG logo
Entry  Thu Jan 1 01:15:45 2009, Yoichi, Summary, VAC, N2 line leak ? 
    Reply  Wed Jan 14 09:22:43 2009, steve, HowTo, VAC, N2 supply pressure lowered for vac valves n280d.jpg
Message ID: 1226     Entry time: Wed Jan 14 09:22:43 2009     In reply to: 1212
Author: steve 
Type: HowTo 
Category: VAC 
Subject: N2 supply pressure lowered for vac valves 

I've been replacing the N2 bottles recently.
I noticed that the consumption is too high. I had to replace them every two days.
Normally the interval is three or more days.
I suspect there is some leak in the line.

Strangely, it is always the left hand bottle which goes empty. The right hand bottle has been
there for more than a week at about 1000 psi.

We should check it when Steve is back.

All vac valves operated by N2
The two cylinders are located in entry room 103
There is an auto switch over valve between them to insure continuous supply.
The pressure regulator should be set 70 PSI on the gauge
This pressure we keep constant.
All vac valves will close in case of running out of N2 or losing ac power so
it is essential that one replaces empty N2 cylinder.

Simply disconnect large CGA580 fitting with a crescent wrench.
Swap in full cylinder from outside, reconnect fitting tightly and open cylinder valve.
Now you should be reading the full cylinder pressure.
Write each cylinder pressure and date-time on the board so one can see if there is a leak
Attachment 1: n280d.jpg  53 kB  | Hide | Hide all
ELOG V3.1.3-