MDE Manifold

[NeilB]

OK Folks, I have an MDE manifold with isolator joining my twin 10s together. Recently the valves have not been as smooth as they should be to open and close. So I though it was time for a clean and gentle lube - first time I have done it to these valves.
On all my other valves I can remove the knob and unscrew the spindle with pressure in the cylinder. Obviously I can't do this with the isolator but can I do it to the two side valves without draining the tanks?

[access]

No, Drain the tanks as the part that you are taking out is under pressure.
I can't see how you can service any valve with pressure in the tank!
I could be wrong but would like to know how?

[MartyC]

He He, Your not wrong, Neil if you can manage it let the rest of us know how!

[NeilB]

On most valves that I have come across the spindle turns a slug that has the valve seal on. So you can take the spindle out and clean and lub the shaft with pressure in the tank.
In my experience it is usually the shaft of the spindle as it passes through the nut that starts to stick and causes the valve to be stiff. Probably from people over lubricating it and crap getting caught in the grease.
Very rarely have I seen the slug get stiff.....except in Apex case when their plastic ones crack and spread out so that they don't come out without a drill!

Anyway I will use the twins on Friday and have a look when there is no pressure in there. If I am wrong there is no harm done and I can do the isolator at the same time. If I am right then I will post piccys.

[NeilB]

A double post.....how did I manage that.....must be twins....double post ...geddit?

[Mal Bridgeman]

I don't know how the internals of an MDE valve work, but on my valves I have to remove the "slug" to clean it and grease it for smooth operation. .... which can only be done on an empty set.

HTH
Mal

P.S. Don't let NickB or Gary (WWD) know that the MDE valves need maintenance - that really would be the final straw

[wilbo]

- so you only leave the brass slug in there - without emptying the cylinders? that's trusting that brass thread!

[nickb]

Originally Posted by NeilB

On most valves that I have come across the spindle turns a slug that has the valve seal on. So you can take the spindle out and clean and lub the shaft with pressure in the tank.

DO NOT TRY THIS AT HOME KIDS.

On a balanced valve, the pressure equalises either side of the slug through the threads and maybe also via a groove or pin hole. There's an O ring at the knob end of the spindle that prevent the gas getting out. Once you remove the end nut the gas is free to come out and, at pressure, you wouldn't want to be anywhere close when this happens.

[NeilB]

Originally Posted by nickb

DO NOT TRY THIS AT HOME KIDS.

On a balanced valve, the pressure equalises either side of the slug through the threads and maybe also via a groove or pin hole. There's an O ring at the knob end of the spindle that prevent the gas getting out. Once you remove the end nut the gas is free to come out and, at pressure, you wouldn't want to be anywhere close when this happens.

No it don't....well it does but only once the valve is open. When it is closed there is no pressure between the slug and the spindle.

I have on many occasion removed the spindle and nut to clean the o ring or spindle shaft. Nothing bad has ever happened. In fact you know there is no pressure there becuase once you have moved the nut a quarter turn you can undo it by hand.

[Bottle Maker]

I have looked at two valves both MDE one on a 300cylinder one on my 232 7s there is know way they willcome apart under pressure without releasing the contents.

Graham.