Leaking... How much?

[Hoosier]

I almost complete my 2nd chamber project... Yahoo..

However, there are a couple of leaking spot including the gauges and bleed valves.

In brief, here is my chamber design.

Triple PO filter - gauge #1 -bleed-check-2nd chamber-bleed-gauge #2-check-3rd chamber.

After pressursing,
Gauge 1: 1750 psi
Gauge 2: 1800 psi


After 24hrs,
Gauge 1: 1520 psi
Gauge 2: 1650 psi

Is this acceptable margin?

Thanks in advance,

 

[pescador775]

"Acceptable" is a relative term. I would say it is acceptable if tanks are being filled daily. However, the leak down will increase, presumably, at 3000+ psi. If the tape is not working for you try the teflon paste. That stuff is very effective, particularly when joining stainless and especially if 1/8 pipe thread is in use. However, a clean single wrap of tape should work fine on brass, 1/4 inch thread. If not, the paste will, especially if the piece is being screwed into aluminum.

 

[Hoosier]

I submerged the system in UW. I couldn't find any leaking point.

Many folks mentioned about a check valve leaking. What do you think?

 

[captain]

I have found most check valves leak over time. If you need positive shut off put a standard valve either before or after the check valve.

 

[jvisser]

I don't mean to hijack this thread, so please excuse; if it's digression, I'll delete it.

I'm not sure I understand the first post completely, but I take it that among the design goals is to maintain the purifier pressure, in the name of cartridge longevity. Is this so?

My perhaps simpler Bauer-based system has leakage problem. The purifier doesn't hold pressure. There appears to be a check valve between the Purus compressor head outlet and the P0 purifier inlet. By the action of the pressure gauge on the filler whip it seems that the P0 integral pressure maintaining valve is operating at about 2200 psi. But, left a few hours after filling a tank, the P0 pressure is zero.

My questions are, should the purifier stay at 2200 indefinitely? How can one detect and cure leaks (which I think it the original poster's question)?

Thanks,

jv

 

[Hoosier]

JV,

Yes, that is my original question.

Many posters mentioned about a check-valve leakage based on their experience. It sounds like that it is common issue on the check valve. I am not sure if there is any qualirty difference between the brand because I can see a wide variance of price.

Most common way is to use a soapy water for a leaking check up.

 

[captain]

Both check valves and backpressure valves are not positive shut off. If you really need to hold pressure use a positive shutoff manual valve. With all the connections and O rings some leakage over time is expected. A small leak on say an 80 cuft tank may only be noticable after several months but the same leak on a filter system that is only 2 or 3 cuft will be noticeable in a few weeks or even days.

 

[pescador775]

Visser, I don't recall seeing a check valve between the third stage and the condenser of a compressor except in some homemade rigs for reasons not germane to the thread. I suppose, over time, there could be some leak back through the poppet valves and tubing of the compressor which would draw down the pressure inside the condenser. Tubing fittings or pipe fittings are a more likely source of small leaks. Perhaps that is what you are seeing. Hoosier is trying to maintain a head inside a large volume filtration system so that gas and compressor run time are not wasted when the unit is started up from idle. Of course, valving is the way to do this as pointed out by Captain.