Importance of a Pressure Regulator

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Liam David
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Importance of a Pressure Regulator

Post by Liam David »

How critical is a pressure regulator for the admittance of deuterium into a vacuum from a pressurized bottle? In the FAQ it says that without a regulator the line would blow.

Couldn't you just install a valve between the tank and the chamber, open the deuterium tank valve a crack, close it, and then open the ball valve on the line to admit the gas into the chamber? Sorry for the stupid question. Money is getting rather tight.
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Richard Hull
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Re: Importance of a Pressure Regulator

Post by Richard Hull »

A regulator is a must have item. Tank pressures vary from 1500 to 3000 PSIG. You need to reduce the gas line pressure to 1-2 PSI and then use a needle valve to admit the flowing gas to the fusor while under continuous vacuum pumping. Gas feed is part of the art of running fusor. Again, no way around a regulator.

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Fusion is the energy of the future....and it always will be
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Chris Bradley
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Re: Importance of a Pressure Regulator

Post by Chris Bradley »

You'll have to have the capability of regulating the flow to 1 to 10 sccm. You are not going to accomplish this with the setup you describe.Yes, you could add bottle-pressure gas to a small reservoir and then take a feed of that, but you will still have to have fittings pressure-rated.

You will find that if you fit a regulator there will be several cc's of volume between the bottle valve and the regulator. I simply crack open the bottle very slightly and very quickly to fill the high pressure side of the regulator with 20Bars worth (I don't even allow out the full bottle pressure) and then close the bottle again. That is plenty for several runs, which I can control on that regulator. My bottle is never left open during any operations, it is all and only from that volume within the HP side of the regulator.

Yes, I would say you need a regulator. You are just making your task nearly impossible otherwise. You need fine gas control else you will not be able to operate the conditions. You need to be able to set the controls up and see a steady few sccm come through, then adjust pressure on the chamber valve. You will have too much else to deal with when you are controlling electrical inputs at the same time.

See viewtopic.php?f=6&t=3224 for the importance of accurate flow control.
Jerry Biehler
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Re: Importance of a Pressure Regulator

Post by Jerry Biehler »

You must have a regulator. If something were to happen and the line from the tank to your chamber were to get kinked you would have full tank pressure in the line and it may not support it. Or say you left all the vacuum valves closed on the chamber and you had a leak in the tank valve or the ball valve. Your chamber could explode from over pressure if it is a typical conflat sealed chamber.
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Dennis P Brown
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Re: Importance of a Pressure Regulator

Post by Dennis P Brown »

Agree with all of the above but will add that deuterium gas is rather expensive and an explosion hazard. The small cost of a regulator will save by helping to minimize deuterium gas usage - gas that will be wasted trying to get the correct amount in the line. Also, if a leak does occurs, a full pressurized line to an open tank will rapidly vent a large quantity of gas into the room possibly creating an explosion danger. While both these issues are not terribly significant, the cost of a regulator is minor compared to the risk.

That all said, I will add that following Chris' method of just opening the tank valve to get an initial volume of gas and then closing it is the safest manner to use a regulator. I was in a room when a regulator (main tank valve still open) diaphragm failed and the contents of the entire tank loudly and violently emptied into the room - luckily it was just nitrogen. Never leave a tank main valve open with the regulator - those units do fail.
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Liam David
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Re: Importance of a Pressure Regulator

Post by Liam David »

OK. Thanks for the replies. I bought a two stage hydrogen regulator just this morning for about $100. It was one that would usually sell for 300+.
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Richard Hull
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Re: Importance of a Pressure Regulator

Post by Richard Hull »

I have purchased a hydrogen regulator as well, but it is not in use as I am still using the two stage oxygen regulator I bought at a hamfest in 2000 for $5.00 It has done well on fusor III and IV since 2001. The hydrogen regulator is planned for use on fusor V.

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
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