Hydraulic test set up

I'm planning a hydraulic tester for small boilers.

Water tank to pump, pump to T piece with gauge, pipe to bolier connector. Stop cocks: I've seen some with one after the gauge, some with one before and one after the gauge and some with none.

Is a stop cock needed? Would the setup be improved by adding one or two?

I think there would be benefit from a stop valve between the pump outlet and the gauge. Isolating the pump from the boiler would eliminate pressure drop due to pump valve leakage.

Liquids are generally fairly incompressible. A small internal leak would soon be identified by a drop in pressure. A valve after the pump would facilitate this option and take any back-leakage, through the pump, out of the equation.

Edited By not done it yet on 03/03/2019 20:26:17

Thanks gents, valve between pump and gauge it is then.

Two valves in series in liquid pipework have a potential issue that if you leave them both closed with fluid in the system thermal expansion can cause severe damage. The gauge will allow some expansion but if the pipe volume between valves is much larger than the volume of the bourdon tube in the gauge even normal UK daytime temperature changes could damage the gauge. One valve between pump and gauge will do all you need.

Robert G8RPI

Edited By Robert Atkinson 2 on 03/03/2019 21:54:30

The idea of a valve to isolate potential leakage from the pump is a nice one, in theory. In practice anything but a brand new boiler without its fittings is unlikely to hold pressure at a constant value without some top up. Anyone who thinks different has obviously not tried to test one on the frames or in the engine that has been round the track or field a bit or lives in la la land!

The fact pressure is lost during the test is not necessarily a reason to fail it, the important thing is identifying where the leaks are and if they are structural or have implications on the base integrity. The fact the regulator or valve glands leaks when doing a cold hydraulic is not the end of the world. So if it's a general rig that will re test boilers that have been in service I doubt the valve will get much use.

Paul.

Looking at the title I was all set to start sharing my experiences testing oil well pressure equipment at 15,000 psi and above ...

Sadly, having ready the above posts, I can't find any excuse.

Colin

If practicable, best practice would have the gauge on a different connection to vessel than the one the fluid is pumped in via.

Alternatively, letting the pressure down after test by a valve from separate connection from pump at least confirms that the vessel has seen pressure.

Pumping some fluid through the vessel to overflow before fitting final blank also gives some comfort that there are no blockages preventing pressure reaching vessel.

Make sure, if you've got a valve in between the pump and the boiler, that you don't kid yourself into thinking that the boiler is leak-free, when all you're actually doing is to pressurise the pipe between the pump and the (closed) valve...

I use one of these 

Edited By JasonB on 05/03/2019 07:49:24

Re my previous post tried 3 times but could not get the link to behave

H

Worked for me Harry, just clicked on it and went straight in.

Ron

Harry's odd-looking link works OK for me too.

I had the same problem the other day and had to log-out and in again to fix it. The whole post had to be retyped from scratch.  I think the URL editor as downloaded into my browser was damaged and copied the raw URL into the description.

Test to see if I can create the URL properly: Harry's link is to a commercial 2.5MPa Hydraulic Pump used for testing pipework on ebay. (2.5MPa = 362psi) Didn't know such things were available and so cheap!

Dave

Edited By SillyOldDuffer on 04/03/2019 10:47:04

Worked fine for me too, clicked on it -straight in

George.

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**LINK**

https://www.ebay.co.uk/itm/25KG-2-5Mpa-Hydraulic-Manual-Water-Pressure-Test-Pump-Pipeline-Tester-Machine/263932244875

MichaelG.

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 Superfluous post; given that S.O.D. has done it already.

Edited By Michael Gilligan on 04/03/2019 14:58:50

Hi Guy's the actual link worked for me too what I could not get it to do was look like the link in blue as above, I've done it that way many times but today it just would not work for me

H

Same here works for me.

You can use literally any type of pump bicyle, grease gun etc all you have to do is put a guage on and fill it up wit oil or water.

Its all i do for testing cylinders and end plugs to operate at 4500psi and test to 6700psi. Fill cylinder with water and pump oil in. If blows will only go about 2"

The initial boiler test should be for 2 x working pressure, so for an operation pressure of 50 psi, pump boiler tp 100 psi (100 psi WP/ 200 psi TP) and this should be maintained for at least 20 minutes to check for leaks or problems.

A bike pump would be a bit under size. (A 3/4" dia punp and would require a force of 226 lb). Have tried a grease gun but it did not work well pumping water.

I would not reccomemnd using oil as it will contaminate the water in the boiler and cause foaming when you put it in steam.

Paul.

Edited By Paul Lousick on 05/03/2019 07:47:16

Edited By Paul Ainsworth on 05/03/2019 11:27:31

Didn’t realise a bike pump would generate 6700 psi, you learn something new every day.

Dave W