Antique pressure gauge

I put this 8 1/2 pressure gauge on my compressed air system:

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It looks awesome and can be easily seen from afar.

Now I am beginning to worry that I put it in the wrong place. It is fed by an air line right next to the output of the pump. Because of this, when the pump runs, the gauge fluctuates a bit as the air "puffs" in the line, and I am afraid that the mount of the needle was not designed for that and it will fail after a few months.

Is this a valid concern and should I connect it to something other place in the tank, where the pressure is more stable?

i
Reply to
Ignoramus27433
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That is a cool gauge! And if it were mine, I would certainly plumb it into my system. I agree about the danger in its twitching - it would be shame to have the needle loosen.

Now, about the structure that the aux tank sits on: I am not a cautious person, at all, but I think that it should have a couple of diagonal braces. Not that I don't trust your welds, it would just be prudent.

Bob

Reply to
Bob Engelhardt

"Ignoramus27433" wrote in message news: snipped-for-privacy@giganews.com...

The glycerin-filled gauge on my log splitter pump jumped its gearing, possibly from vibration as the relief setting isn't much over half scale on it.

Your gauge may have internal threads for a "pressure snubber" screw or you could add one in line.

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jsw

Reply to
Jim Wilkins

Bob, it has some reinforcement braces near the floor, you do not see them on the picture. It is sturdy enough.

I will re-plumb the gauge into the tank directly. It looks like we both agree on that. It was a mistake to plumb it near the output.

i
Reply to
Ignoramus27433

Thanks, Jim, you are the third person who shares this concern, I will do one thing or another, add a snubber or hook up somewhere else.

Reply to
Ignoramus27433

If you plumbed in an orifice followed by a small tank to absorb the remaining impulses you could leave it there . Or for that matter a larger diameter line to the gauge might be enough .

Reply to
Terry Coombs

Yes, that's a valid concern. Is there another plugged boss where you could mount it in the tank rather than at the compressor outlet? Many tanks have multiple bosses for running the piping from a different direction. Or insert it above the union on the tank outlet plumbing at the right.

Also, a concern I have is that the large gauge is out in the open and can easily be damaged. Consider putting a shield around it, Ig.

Yet another concern is that the outlet is on the very bottom of the (white upper) tank, ensuring that all moisture in that tank comes out in the air line. Very strange.

Reply to
Larry Jaques

I just learned something. Thanks

Reply to
Bob Engelhardt

If that won't work out, you can make a pneumatic low-pass filter. Just put a restriction of some sort (I was thinking of some purpose-made gizmo with a small orifice, but just a valve will do -- crack it barely open and leave it), then a couple of feet of largish-diameter (1"?) pipe, then your gauge.

Fast variations will be lost, but slow variations will register. If you do it with a valve, you can adjust the tracking speed by opening or closing the valve.

(Larry's idea is better, if it works).

Reply to
Tim Wescott

Yes, I will look into something, or other.

That is for draining.

i
Reply to
Ignoramus27433

Here it is, called a Throttle Screw:

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-jsw

Reply to
Jim Wilkins

I'll bet the rubber hose he used initially helped dampen the bounce.

Good idea, if there's one in the line already.

Yeah, the direct output of the compressor has far too much variance in pressure for a poor gauge to survive.

The same is true in car engines for vacuum gauges. The farther away from the cylinders, the better. Directly under the carb is the best.

Reply to
Larry Jaques

I could have sworn I saw a quick disconnect fitting on the end of that line, Ig. Oh, well.

Reply to
Larry Jaques

Simply add a restiction between the line and the guage to slow down the response. A needle valve that you can adjust works well, so dose filling a pipe nipple with solder and drilling a very fine hole through it. Since there is virtually no flow, the restriction will have virtually no effect on the pressure but WILL damp out the fluctuation

Reply to
clare

They make "pulse dampers that are used between a gauge and a pulsating source.

Reply to
John D. Slocomb

If you didn't notice the references I posted to gauge snubbers, one suggests starting with an 0.020" hole.

Several sizes of these bits have worked well enough for me in brass, better than the #61-80 set from Enco.

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I tried one in steel and it didn't dull instantly, FWIW.

-jsw

Reply to
Jim Wilkins

Is there a check valve between the pump and tank? If so, you are not reading tank pressure. If there is not one, there should be so the pump unloader can work.

Reply to
aasberry

it does not need a check valve.

Reply to
Ignoramus16276

Put in a snubber, everything is great now. Thanks for the advice.

i
Reply to
Ignoramus16276

Ignoramus16276 fired this volley in news: snipped-for-privacy@giganews.com:

Yeah... I have no idea what that poster was thinking... it had nothing to do with gauging.

Ig... If you need to plumb the gauge in a pulsing line to make it more accessible or visible, they sell "gauge line snubbers" designed to do exactly what you want -- take the pump pulses out of the stream before they reach the gauge.

Lloyd

Reply to
Lloyd E. Sponenburgh

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