GTA
All Springer/NP/PCP Air Gun Discussion General => Machine Shop Talk & AG Parts Machining => Engineering- Research & Development => Topic started by: stalwart on January 15, 2016, 04:30:04 PM
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I am working on refining a homemade hydro testing rig, and it's first use ( https://www.youtube.com/watch?v=CwL5x_vF0s0&feature=youtu.be (https://www.youtube.com/watch?v=CwL5x_vF0s0&feature=youtu.be) ) has made it clear the rig needs refinement.
The mess seen in frame is nothing, compared to what the immediate area looks like (This is the first, and last indoor test). So...
My question is: Is there something I could add to water that would allow me to use that, and leave it in the pump, without corroding the pump during storage? I only know that water based cutting/cooling fluids have protection for the tools... would that be a smart place to start looking?
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When you say PUMP ... what type pump we talking about ?
Are you using AIR to push fluid , or is pump compressing fluid ?
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It's a "Porta-Power" hand pump (Chinese Porto-Power clone). All fluid.
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It's a "Porta-Power" hand pump (Chinese Porto-Power clone). All fluid.
Ok, so PUMP is meant to pump Hydraulic fluid ... but your asking if you can use WATER with an anti corrosive component then ?
BEST way I see is incorporating a vessel ( Cylinder w/ floating piston ) between the pump and test apparatus.
This cylinder has a o-ring sealed piston able to float between ends, then a long coil spring inside compressing piston towards one end. This is the end where your pump is located.
As you force oil into cylinder the piston is moved towards the other end of cylinder.
Now on the other side of floating piston can be your water going into test fixture.
In this way you isolate fluids, no contamination.
If a failure happens all you loose is clean water.
Simply releasing bleed off on pump has spring retract piston and fluid returns to pump.
Rebleed the water side and go at it again & again ... ;D
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Correct. I used winter grade hydraulic fluid for the first test, and lost nearly $9 worth of it... but, that isn't even close to being the major expense...
Cleaning the stuff up took enough shop time to make that peanuts. Outdoors will be easier, but I can't be leaving puddles behind.
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Added content to above
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Very good thinking, Scott. If I can't find a fluid for this, it may be my only option.
I could, if I choose, build a system that allows me to double (or any ratio) the power of this thing, right?
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Very good thinking, Scott. If I can't find a fluid for this, it may be my only option.
I could, if I choose, build a system that allows me to double (or any ratio) the power of this thing, right?
Pump side output can move more or less the floating piston with differing diameters. But because floating piston of the chamber would have the same area either side of piston there would be no change in that regard within this part of system.
Also understand larger in diameter this chamber becomes, MORE fluid it takes to move displacing the water on otherside of the piston. As well beefier wall thickness etc needs to be. For a near static minimal flow HP test fixture you don't need much displacement to take place.
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If you use a larger piston and bore on the pump side and one, say, half the area (piston and bore) on the output side, you will double the pressure downstream to use for testing.... Basically, you are building a booster pump....
eg. 1" bore pump side - area = 0.785 in^2, at 10,000 psi force = 7850 lbs.... If the downstream side is 0.707" bore - area = 0.3925 in^2.... 7850 lbs. applied on that area gives 7850 / 0.3925 = 20,000 psi.... but only half the volume displaced....
In addition, if you get a break on the output side, the piston will simply bottom out in the large cylinder.... The space on the downstream side of the large piston will have to be vented, or the air there might superheat on a sudden failure.... Alternately, it could be filled with oil and vented through a small orifice into a holding tank (which is vented) which would cushion any sudden failure....
Bob
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Scott... Yeah, there is actually very little volume moved, when the system doesn't leak.
I'll eventually need a lot more power to test my 4.5K design to destruction, and am thinking that a 2:1 ratio would be fine, and given the tiny amount it would have to move, the booster wouldn't have to be very big.
I have to get through the 1.8K tests (FDPCP) first, and the rig will suffice for now (with the noted exception).
Bob... Looks like there will be more of my homework to check, as if my life depends on it. As soon as the Gen 1 thing is put to rest.
I already feel better, I hadn't thought about what to do when the gun failed.... and a cushion may save quite a few gauges. Good idea, as always. Thanks.
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Eric,
the final output headed to the part being tested should have a very tiny flow restricting orifice in the line, right at the booster pump. That will slow the gush of water if/when you have a failure. The booster/multiplier pump is a good idea.
Lloyd
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Eric,
Everybody has their favorite stuff, but this is the series of fittings I like to use in the shop for HPA and hydraulic test fixtures.
http://www.mcmaster.com/#52215k621/=10pnuwb (http://www.mcmaster.com/#52215k621/=10pnuwb)
1/8" O.D. annealed steel tubing. They are relatively inexpensive, and the ferrells are only 88 cents each so you don't mind throwing away a section of line if it gets a kink in it. They are only rated to 4000 psi working pressure, but I would guess they are highly derated to that 4000. Also, you can them apart and put them back together with a 3/8 and 7/16 wrench and no having to worry about leaking pipe threads. Just my 2 cents.
BTW, if someone were doing testing to 10,000 psi and expecting a failure and was adequately protected from the imminent "release", someone "might" use these 4k fittings in the hopes that their safety margin is above the 10k, which could be the case. I know someone who used these to 10k on a one-usage-and-then-throw-away, type of deal, without issue. We have to make our own decisions, though, and take responsibility for them.
Lloyd
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Thank you, gentlemen!!
8) 8) 8)
V2 is already simmering in my head, ahead of schedule. I'm formulating a rig with the booster and probe integrated (or, at least in close proximity) to keep the high pressure away from me... the boost rate high enough that the pump, gauge and hose will never see their max... and an inability to move any real volume, as it is never needed.
This is a big deal to my tiny endeavor, and is most appreciated.