Recently i have been looking to add a mass flow controller to my set up and have come across a few bumps in the road i am having some difficulty getting over. I have searched the forums quite extensively and have found little information on the specifics of the MFC such as the optimal flow range, the best reference temperature or connectors , the most common fittings or external seals/ valve seat. Obviously most of us use MFC set for D2 but those of us who don't how do you manage that. Personally i think it would be nice to have a reference to how you guys make your decisions on what specific MFC to purchase, There seems to be a cross road with a million different paths in front of me when deciding which specific configuration MFC to buy. a bit of guidance would be greatly appreciated.
-Juan Dosio
specifics of Mass Flow Controllers(MFC)
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Richard Hull
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Re: specifics of Mass Flow Controllers(MFC)
Most fusors built here do not use an MFC. The MFC would be one of the last items one might consider when building a fusor especially if cost is a factor. I have five MFC's and haven't used them on my fusor. Just another thing I stumbled on and bought that I did not need. A few discussions of late have mentioned them. Nice to have, but not needed.
Someone who is using one and is qualified in some of the details might do a FAQ on them. In a much older posting, Carl Willis gave a good chat on how to get gas into a fusor without the need for an MFC, mentioning they were sort of an overkill.
Richard Hull
Someone who is using one and is qualified in some of the details might do a FAQ on them. In a much older posting, Carl Willis gave a good chat on how to get gas into a fusor without the need for an MFC, mentioning they were sort of an overkill.
Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Jerry Biehler
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- Location: Beaverton, OR
Re: specifics of Mass Flow Controllers(MFC)
You can get a used mfc for the price of a good vacuum rated needle valve.
First you need to know what the conductance of your high vacuum pump is. I would not recommend running wide open, you will waste a lot of D2. You can either throttle it down with an oriface plate or something like a butterfly or gate valve. Once you have an idea of conductance you can figure out the ideal gas flow into the system to reach the designed pressure. Then pick a MFC.
MFCs are rated for specific gasses since the properties of the gas effect the reading. There are conversion charts online that give correction factors when working with gases so if you get one intended for argon you can figure out what the conversion is to H2.
They are easy to conrtol but I picked up a matheson MFC and controller box for something like 50-75 off eBay a while back. So if you can find one with a controller it is pretty easy to go. The connectors on the MFCs are pretty standard, you will fine one of three on the older style analog MFCS, a card edge connector, a 15 pin d-sub, and a 9 pin d-sub. For the most part they are interchangeable, thought you wan to varify before mixing and matching.
First you need to know what the conductance of your high vacuum pump is. I would not recommend running wide open, you will waste a lot of D2. You can either throttle it down with an oriface plate or something like a butterfly or gate valve. Once you have an idea of conductance you can figure out the ideal gas flow into the system to reach the designed pressure. Then pick a MFC.
MFCs are rated for specific gasses since the properties of the gas effect the reading. There are conversion charts online that give correction factors when working with gases so if you get one intended for argon you can figure out what the conversion is to H2.
They are easy to conrtol but I picked up a matheson MFC and controller box for something like 50-75 off eBay a while back. So if you can find one with a controller it is pretty easy to go. The connectors on the MFCs are pretty standard, you will fine one of three on the older style analog MFCS, a card edge connector, a 15 pin d-sub, and a 9 pin d-sub. For the most part they are interchangeable, thought you wan to varify before mixing and matching.