FAQ - How to conserve D2 gas and avoid leak down

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Richard Hull
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FAQ - How to conserve D2 gas and avoid leak down

Post by Richard Hull » Wed Mar 06, 2019 7:24 am

Carl Willis long ago posted that you must purchase a special regulator for hydrogen gas only as other types of gauges can leak down over time when not in use. Naturally, if you are not using your fusion system, you must close the deuterium tank or bottle valve. this is for safety sake and just common sense. Over days or weeks the high pressure gauge typically falls to zero.

Following Carl's suggestion, I ordered my custom hydrogen only gauge and spent $100, but still have never hooked it up. (typical here in my lab of slothfulness). Thus, I am still using the old "adapted" Victor oxygen welding dual gauge regulator. I did install a 0-3 PSI line gauge on the low side of the regulator. I have used this large, out-sized gauge since 1998.

I have a trick..... I slowly open the main D2 bottle valve and only let in a low pressure of maybe 200- 400 PSIG on the high pressure gauge and then cut off the bottle completely. This means that in the tiny volume of the high pressure gauge I have 200 PSIG of stored D2. The deuterium tank is no longer on line or feeding my gas system. Only the high pressure gauge's "dead volume" is my D2 supply.

I have set the low pressure output regulator for about 1.5 PSIG. This pressurizes a CO2 cartridge tank in the small copper line to that low level. Then I run the fusor like crazy for an hour or two using the bleeder valve in the gas line to feed the fusor.......Slowly, the dead volume of the high pressure gauge yields to the 1.5 PSIG tank and line as I flow gas into the fusor. I note that all the time, during my fusor runs, the high pressure gauge is slowly dropping. I usually end my session when the high pressure gauge is nearing or at 0. If I want to keep going for another hour, I just barely crack the D2 bottle valve, once again, and put a little more in the dead volume of the high pressure gauge and continue until it is exhausted. I must tell you to take your fusor voltage back to zero before replenishing the high pressure gauge. (more on why you should do this , below...)

A great tip. Never, ever leave your D2 bottle valve open, nor open it all the way. Just crack the valve enough to let in a tiny bit of high pressure gas and use the dead volume of the high pressure gauge as a main high pressure storage tank and put a small tiny back up volume tank in your low pressure gas line as a bit of a buffer.

Just be sure your high pressure gauge doesn't go to zero during a run or your fusion fire will die as the voltage climbs due to light current loading and reduced D2 pressure. I have had this happen and it is easily corrected. All you need to do is just crack the bottle valve again to continue on as before. Note*** Turn your voltage down or off before cracking the valve as the fresh gas pressure may overload your supply or burn out your grid. Just bring the voltage back up normally to your "sweet spot". you may also have to adjust your bleeder fine control valve again.

Again, this is a neat little trick to conserve gas and avoid having a high pressure gas leak down over time. Remember, key to the process is a dual gauge system regulator with an ultra low PSI gauge set to a very low gas line pressure and you must have a very small tank in you low pressure gas line as a buffer. (I used an old CO2 cartridge that I silver soldered into the copper line.) You must be mindful all the time of the high pressure gauge reduction in pressure due to gas usage while doing fusion. It is an art....You will get the hang of it.

If you are working at very high pressure leak rates i.e., 30-50 microns as seen in some 2.75 cross fusors you will need to FILL the high pressure gauge all the way to max pressure then cut the tank off, as you are gobbling up your gas in such a fusion system.

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
Retired now...Doing only what I want and not what I should...every day is a saturday.

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