way off subject

jgra1 · Unread post by **jgra1** » 07 Aug 2006, 16:50

Did not really know where to put this

I have a very old Broom and Wade compressor. Basically a motor/belt driven single cylinder upright engine, and a seperate (80?) litre tank.

It will not get above 40 psi

the gauge goes up to 120 .. I took the head off and poured oil into bore, it was engine oil so quite thick, but hadn't gone past rings over night..

what else could i do? I presume I just need a much higher compression ratio? I could skim.. hmmm

will have a look at whatever controls input/output of air from cylinder.. no valves as such..

John

James.UK · Unread post by **James.UK** » 07 Aug 2006, 17:02

There has to be a non return valve between the compressor and the tank somewhere.. Sounds like its leaking back somehow..

jgra1 · Unread post by **jgra1** » 07 Aug 2006, 17:08

thanks James

i will look later.. but it must have reed valves or similar?

AndersDK · Unread post by **AndersDK** » 07 Aug 2006, 23:50

No -

The valve James refers to is the valve supposed to be in-line with the pipe from the compressor cylinder to the tank. Could be part of - or built into - the pipe to tank union.
Its a very simple valve with a small/weak spring just barely holding the valve closed against the cylinder pressure. You could in fact test it with your mout blowing into the tank thru the valve (not practical

).
In principle this valve works like a bike or tyre valve.

jgra1 · Unread post by **jgra1** » 08 Aug 2006, 11:24

thanks guys..

I will look at that.. in the mean time I looked up inside the head. There are two (lightly) sprung valves in there. So, I guess the idea is, the compressor piston moves down and sucks air in, and on the up stroke simply pushes it straight back out of the exhaust. So the pressure build up is caused by the tank itself. If the non return valve mentioned by James was malfunctioning, the compressed air would probably be drawn back into the cylinder again?

J

bxbodger · Unread post by **bxbodger** » 08 Aug 2006, 13:30

Are you certain it's not just the gauge malfunctioning- mine certainly does: it reads 40 psi when the tank is unpressurised!!

If the tank has a condensation drain valve underneath check the rubber seal on that as well-if it's old it may have perished.

jgra1 · Unread post by **jgra1** » 08 Aug 2006, 21:49

thanks BX...

no it feels pretty weak.. cant use it to inflate tyres very well.. I used to own it and I am sure it got to 80-100 psi.. left it with a mate for 2 years and now its rubbish

I want to spray my camper..

unless.. anyone who wants easy cash spray it for me

?

john

demag · Unread post by **demag** » 10 Aug 2006, 02:15

On all the compressors I've ever used there's always been some sort of safety pressure relief valve on the tank somewhere just in case there's some sort of blockage and the thing goes into warp factor nine!

Also how is the compressor driven? Belt? If so is it any good? If it slips you will not get up to pressure.

There's more

Does the motor cut in and out or is it a permanent pumper?

If it cuts in and out the motor must be controlled by a pressure switch. The switch could be faulty i.e. dirty contacts. Especially if it's stood for two years.

jgra1 · Unread post by **jgra1** » 10 Aug 2006, 09:58

thanks Demaq

its a permanent pumper

I thought about the belt, but the thing turns over all of the time, you can hear each pump, if the belt was slipping this noise would stop?

Saftey valve, i have taken apart and checked, and reset it at a level that is not too high (to start with). There is no escape of air from it at 40Psi..

The whole thing is very archaic... I am tempted just to be a modern oil free one for £50 ...

J