From: Geary Eppley (eppley_at_physics.rice.edu)
Date: Thu Jan 30 2003 - 15:58:28 EST
Hi Bill,
We would like to get safety approval to run isobutane in the TOFr gas
system starting February 10. A schematic of the gas system is attached.
The normal flow is 63 ccm r134a and 3.5 ccm isobutane. The isobutane flow
meter is slaved to the r134a flow meter and this ratio is automatically
maintained up to the maximum flow of 450 ccm r134a. To provide a double
check, we will monitor the flows with A-D input to a PC which will compute
the ratio and write the value (isobutane flow / r134a flow) to a slow
controls disk once per minute. Slow controls will monitor this ratio and
alarm yellow if it is outside .050-.055 and alarm red if it is >.080.
The shift crew should send email to tofp if the alarm is yellow and should
shut the valve on the isobutane tank if it is red.
Please let me know if we need to provide further information.
Regards,
Geary
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