[Dsg-rtpc] RTPC gas system

[kuhn]

My only concern is about the sensors - everything else seems to be in good hands. To reiterate, here is the dream wish list:

1 combination sensor (or small separate sensors) for ABSOLUTE PRESSURE and for Temperature. The required range for both is very small (50 - 100 F and 0.9 to 1.1 atm) but they have to be tiny to fit inside the RTPC. (We need two of each so we can also monitor the DMS, although there space is not quite as much at a premium. We MIGHT get around the pressure sensor for the RTPC if instead we have an extra (tight) gas line that attaches to one end of a differential pressure meter, with the other end attached to the DMS. We must know the absolute pressure in both to within 0.01 (0.14 psi) if at all possible, while the temperature is less sensitive (3 degrees Celsius or 5 F). We can accomplish this either by having an absolute pressure meter at at least one of these two places, or relative pressure sensors combined with a Hall barometer, or some combination thereof with a differential pressure sensor (probably most sensitive). 
I hope the gas group can look into possible sensors for this that are available on the market. The ones suggested by George look way too big, at least for the RTPC. (I think for the temperature sensor, a simple T-dependent resistor or diode should be good enough!)

Thanks - Sebastian

> On Mar 20, 2018, at 4:47 PM, George Jacobs <jacobsg at jlab.org> wrote:
> 
> Hi Carlos,
> 
> The misc swagelock hardware includes valves, fittings, adapters, ferrules, etc. 
> 
> The mass flow controllers have the longest lead times and should be ordered ASAP. A minimum of 2 mass flow controllers should be ordered in order to keep our options between series and parallel DMS setup.
> 
> As far as the temp sensor, would one of the following work?
> https://www.mcmaster.com/#6467t24/=1c2110g
> or
> https://www.mcmaster.com/#3866k43/=1c211mt
> 
> Cheers,
> George
> 
> On 3/20/2018 3:05 PM, Carlos Ayerbe wrote:
>> Hi George, Marc and Brian and all, 
>> 
>> I got noticed from Keith, that we can spend some money on the acquisition of several components for the gas system. 
>> 
>> I was checking and these attachments correspond to the latest configuration. I noticed that the excel file is not updated according to the scheme (just some discrepancy numbers, like how many MFC items are counted). 
>> 
>> There are a few items I would like to understand:
>> - the temperature probe is under interrogation mark, do we have any reference about it? In other words, do we know what do we want? 
>> - the item 'misc Swagelock hardware' is $2,500 but I don't know what are w talking about, valves, hoses, regulators, gauges? 
>> 
>> I would like to confirm with Sebastian (and the others) that the scheme is more or less the starting point to begin building the system, so we can discuss the exact number of components to buy as soon as possible. So, in accordance, update the excel file. 
>> 
>> Thank you 
>> 
>> Cheers,
>> 
>> -Carlos
>> 
>> 
>> ----- Original Message -----
>> From: "George Jacobs" 
>> <jacobsg at jlab.org>
>> 
>> To: 
>> dsg-rtpc at jlab.org, "kuhn" <kuhn at jlab.org>
>> 
>> Sent: Monday, February 12, 2018 9:25:58 AM
>> Subject: Re: [Dsg-rtpc] RTPC gas system
>> 
>> Hi Sebastian, 
>> 
>> Please find attached P&I diagram along with the components list for Series configuration. The list is also valid for the Parallel configuration, so there are options if needed. 
>> 
>> According to the markings on the deck, the magnetic field extends out slightly beyond the cart. Not sure if any part of it is free of the magnetic field. Maybe the field is low enough all the way outboard at floor level? This may require longer and larger ID gas lines. 
>> 
>> Cheers, 
>> George 
>> 
>> 
>> 
>> 
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>> 
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> 
> -- 
> George Jacobs
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> 
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> 
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