Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
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BramR
- Private
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- Joined: Thu Oct 23, 2014 11:20 am
Mon Jun 13, 2016 4:44 pm
Hi guys,
In my current setup, i am using a fire extinguisher as a ''pressure vessel''.
i have a fridge compressor connected to it using quick connect. It has a 12 bar pop-off valve and a manometer which goes up to 16 bar. Currently i'm not upping the pressure any higher then 7 bar for ''safety reasons''. i was looking for a way to test if my tank would be able to support a higher pressure. i read something about hydrostatic pressure tests and this seems like a proper way to test the capability of the tank while reducing the damage it can cause. i was wondering if you guys have any experience with (hydrostatically) testing your air tanks and are maybe eager to share this with me.
if this is a very common question please link me to the post on the site because i cant seem to find anything about this subject.
With kind regards,
Bram R
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D_Hall
- Staff Sergeant 5
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Mon Jun 13, 2016 11:06 pm
Hydrostatic testing is a pretty straight forward process.
1 - Fill your tank with water.
2 - Pressurize the tank to the pressure you're interested in.
Really, that's it! The only question tends to be how do you pressurize your tank. For small tanks (like you have), a hand-powered grease gun is a good way to do it. For large tanks, a pressure washer (with a few adapters in place of the nozzle) is a good way. In either case, *do* use a pressure gauge and beware that if you have zero bubbles in the system the pressure can rise *very* fast and damage your tank. With this in mind, it's often nice to have a very small (<<--- SMALL!!!) bubble in the system to provide a buffer. Note that the larger the bubble, the less safe the procedure so remember that you're balancing likelihood of damage due to rapid pressure rise with safety.
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BramR
- Private
- Posts: 14
- Joined: Thu Oct 23, 2014 11:20 am
Thu Jun 16, 2016 2:41 pm
Thanks for the quick reply!
That could indeed be a problem for me. I only have my fridge compressor to reach the pressures that i want to achieve. This may cause the pressure to rise too quick. I do have a pneumatic quick connect tube which is 2,5mm ID and has a length of about 4,5 m. A quick calculation tells me there will be about 80 mL of air in the tube. The tube is rated for 10 bar and will probably be able to hold a lot more. Do you think this is a sufficient volume to use as a buffer? (so that the compressor has some more volume to compress in and the increase in pressure will go a bit slower)
With kind regards,
Bram R
