[Dsg-rich] RICH gas panel test results

Tue Aug 15 11:38:48 EDT 2017

Hello George, 

Since it was a proof of concept test, we only went up to an output pressure of 75 psi. Also, the OSP says the pressure in the tank should be 80 psi so we did not want to go over 80psi in the event the compressor did not shut off right when its output pressure reached the set point. 

There are also relief valves on the gas panel that are rated for 90 psi. Since we know the compressor does shut off immediately when the output pressure set point is reached, we could set the output pressure to be 80 psi. 

For the length of the 1/2" OD tube, in April, Amanda, Pablo, and I did a rough measurement on the Forward Carriage (FC) for how long cables should be. We measured that roughly 110 feet would allow a cable to stretch from the location of the gas panel on the FC top deck to where RICH will be on the FC. I can go with Mindy to do a more precise measurement so we have a more precise length. 

Best regards, 
Tyler 

From: "Amrit Yegneswaran" <yeg at jlab.org> 
To: "George Jacobs" <jacobsg at jlab.org> 
Cc: "dsg-rich" <dsg-rich at jlab.org> 
Sent: Tuesday, August 15, 2017 11:06:43 AM 
Subject: Re: [Dsg-rich] RICH gas panel test results 

hello george, 
and here i was thinking you as the gas expert and would know all the answers or find out these answers , but apparently i was wrong. 

here, some comments. 

with regards to the length, since we know where the detector goes in the hall and where the compressor and air tank go, i suggest you determine the length to the best of your ability. 
100 ft was a good guess; also adequate length to run it around the clean room. 
mindy please assist george in this endeavor. 

the goals of the test was basically proof of principle that the system works. 
we learned that the system does indeed work, but not 100% as we expected. 

we learned that the wrong pressure gas was either ordered/delivered. 
then there were the issues with connections/ fittings. 
issues with cables. 
we learned that the output N2 temperature was 68F to 72F 
we learned that the flow never quite reached 400 l/m 
and so on and on... 

so we learned all the stuff which wasn't right and all the stuff that needed to be learned, 
one cannot know what one has to know before one knows it. 
or to quote amanda: i don't know what i don't know till i don't know. 

with regards to the compressor set point tyler will explain it to you. 

yes, there were two pre-test meetings on two consecutive wednesdays during the dsg meeting. 
i was requesting t he test to demonstrate proof of principle that the system works. 

so, the end 
amrit 

From: "George Jacobs" <jacobsg at jlab.org> 
To: dsg-rich at jlab.org 
Sent: Tuesday, August 15, 2017 8:53:43 AM 
Subject: Re: [Dsg-rich] RICH gas panel test results 

I have a couple questions on the air cooling system test performed yesterday; 
1) What is the length of the 1/2 OD line that goes from the air panel outlet to the RICH inlet? It started out as a 100ft length. 
2) Absent a written test procedure, what were the specific goals of this test? 
3) Why is the air compressor outlet pressure setpoint so far below the rated output of the compressor? 
4) Was there a pre-test meeting or discussion prior the test? 

George 

On 8/14/2017 2:58 PM, Tyler Lemon wrote: 

Hello, 

This morning Mindy, Marc, George, and I tested the RICH gas panel. Both the nitrogen purge instrumentation and air cooling instrumentation were tested. 

For the nitrogen purge system, we connected the nitrogen dewar to the gas panel. Initially, we were not able to get over 4 liters per minute (L/min) of nitrogen flow as the dewar was not a high-pressure dewar, as ordered. George has already arranged for the correct, high-pressure dewar to be delivered on Wednesday August 16. After noting the dewar was a low-pressure dewar, we swapped the installed pressure regulator with an orifice for a regulator without an orifice. The new regulator without the orifice allowed the nitrogen flow to be set to ~15 L/min. We set the nitrogen flow to 6 L/min and measured the temperature of the gas on the very end of the gas line in EEL 124 cleanroom. The output nitrogen temperature at the end of the gas line was ~69 degrees Fahrenheit. The ambient temperature of EEL 124 was ~72 degrees Fahrenheit. 

For the air-cooling system, we connected the air lines to the gas panel. We set the compressor to automatically turn off if its output pressure reached 70 psi and to automatically turn on if its output pressure drops to 58 psi. The values set on manual instrumentation and the values measured by the mass flow meter are in the table below. To get the flow output to be higher, we had to also increase the pressure to the rotameter using the manual pressure regulator. 

Manual Pressure Regulator [psi] 
	Manual Rotameter [L/min] 
	Mass Flow Meter Measurement [L/min] 

30 
	200 
	200 

50 
	300 
	300 

60 
	400 
	350 

We were not able to get 400 L/min when the manual rotameter was set to 400 L/min. We tried increasing the output pressure at which the compressor turns off from 70 psi to 75 psi, but the pressure at the manual pressure regulator did not go above ~60 psi and the measured flow above ~350 psi. If during the cooling tests, 350 L/min is not enough to sufficiently cool the electronic panel, we could further adjust the output settings of the compressor to try to reach 400 L/min. 

Best regards, 
Tyler 

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George Jacobs
Jefferson Lab (TJNAF)
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(email) jacobsg at jlab.org (website) https://userweb.jlab.org/~jacobsg 

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