FAQ - The best vacuum gauge for the fusioneer??

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Richard Hull
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FAQ - The best vacuum gauge for the fusioneer??

Post by Richard Hull »

There is no best gauge in the vacuum biz! However the fusioneer is not in the vacuum biz. Vacuum, for us, is just another technology we must rise to master at our own level of incompetence. I could write forever on the various choices and their pro's and con's. I will not. You must read the MKS company gauge tutorial before listening to me in my notes below. Go to....

https://www.mks.com/n/introduction-to-v ... easurement

Now to my comments

TC gauge

For the average guy drifting into this endeavor of doing fusion, the first gauge, but not the best gauge must be the rather inexpensive Thermocouple gauge (TC gauge for short). It will be used to qualify any vacuum pump you buy and serve as a rough indicator of fusor operation pressures if you can't afford the best or a better gauge for you fusor chamber.

The TC gauge is easy to maintain and gives rather accurate readings for air and moderately close readings for deuterium at the lower end of its useful scale.

The best gauge

The capacitive manometer

There is no better gauge for the amateur fusioneer where accuracy is concerned. It is gas independent, It reads the true absolute pressure of all gases at all pressures within its range. Most all cover 4 decades with high accuracy. These are all electronic gauges that require no controller to operate! There normal operating ranges are all well within the operating range of a running fusor using deuterium.

Great!..... Price? well....... Purchased new from the manufacturer figure on $1,000 for the gauge assembly. E-bay will be much less if you get one used that is not broken or damaged. I got mine at a hamfest for $20 in great shape. I found another at a Teslathon flea market for $40, also in good shape.

Why no controller?? You will need a plus/minus +15/-15 volt regulated power supply (you can make this yourself!) You will need a common digital multimeter (list price new $6.95 to $200) spend the big bucks and get a $25.00 one brand new.

All capacitive manometers are linear scaled 0v-10v so the multimeter will read pressure directly! All you need to to supply ground - 0 volts, +15 volts and -15 volts and bring the two 0-10v output lines to the multimeter and you have your controller.

Example: a 1 torr rated capacitive manometer will read 10 volts until your vacuum pump line hits 1 torr. As the voltmeter now drops with pressures below 1 torr, at 1 volt on the meter you are at 100 millitorr/ microns. Change your range to 1 volt and at 20 millitorr/microns you will read 0.2 volts. Switch to the .1 volt range and at 5microns you will read .05 volts and so on.


Other gauges are not the ideal gauge. All will never read real deuterium pressure unless you have a correction chart or build an Arduino controller with a lookup table to take the reading and adjust to the real pressure. Thus, all other gauges just like the TC gauge will read in error. For this reason they are not the best gauge and you can perhaps get a great price and versatility in many other type of gauges, but will always need correction factors and all are made to read calibrated for air or nitrogen only. For most this will not matter as for them the best gauge is going to be the one I bought really cheap and has all these features!.

Many will enter here who are very astute and adroit in electronics and programming and can and will build lesser gauge heads into very accurate pressure indicators of deuterium pressures in their fusors. More power to them.

This FAQ was about the first gauge you need and the best gauge you can have for doing fusion in a fusor. Those criteria are listed and satisfied above.
The real value of this FAQ is the pointer to MKS superb explanation of the various types of gauges.

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
Peter Schmelcher
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Joined: Sat Nov 13, 2010 1:56 am
Real name: Peter Schmelcher

Re: FAQ - The best vacuum gauge for the fusioneer??

Post by Peter Schmelcher »

I would suggest finding a Leak is worth some vacuum gauge consideration. I am just not lucky enough to buy a bunch of used parts and bolt them together and have no leaks. I was frustrated years ago with a bad commercial weld (used) and posted about it. The locating procedure required an ionizing pressure gauge and canned air. Just my 2 cents painfully learned.

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