Lubricators

[Deleted]

I've just been fitting the lubricators to my Modelworks Britannia, and they seem to deliver oil nicely to the steam inlet pipes. I'm just wondering how to determine the correct rate of oil flow, and how to adjust the lubricator accordingly. Does the engine need more oil when running in?

The lubricators each have two little O-rings around the plunger, separated by a brass spacer. I believe that these determine the amount of oil delivered on each stroke. The number of wheel revolutions per pump stroke depends on the relative lengths of the crank arms on the lubricator and on the expansion link spindle, which are 45mm and 33mm respectively. The latter is much longer than scale, and I'm tempted to reduce them both in proportion.

Regards, John

www.britanniabuilder.co.uk

[mott]

John, I have a copy for you of an e mail from Steve Baldock which explains the inner workings of the lubricator. Very interesting. he recommedns leaving well alone. I will have to scan it so will send it to you as a pm. Mott

[Jason]

Hi Mott

Sounds very interesting, any chance of another copy for me ;D?

Cheers

Jason

[mott]

Jason, I almost said "God being willing" this system is really stressing me. Send me your e mail in a pm and I will do my best!!Mott

[mott]

Hi guys, I have decided to distill the Steve Baldock message to all.

"Directly under the pump body is an o ring, then a spacer, then another o ring and then a ball. The ball should seat on the bottom o ring held lightly in place by the spring.
The theory about the cycle of events is best started with the pump ram in its lowest position. In this position it should be poking through the lower o ring.It may be touching the ball or even slightly pushing the ball away from the o ring, but that is not important.
As the pump ram moves upwards, through the lower O ring the ball seals against the o ring and prevents oil being sucked back.
The ram is still sealing against the upper O ring.
As the ram moves towards the top O ring it creates a vacuum which is sealed by the ram in the top O ring and the ball against the lower O ring.
The ram continues its upward travel and will eventually leave the top O ring and will expose the two small holes in the pump body.
Oil is then sucked in by the vacuum.
The ram now starts its downward travel. It seals against the top O ring and pushes the oil through the spacer, lower O ring and past the ball.
The thickness of the spacer deteremines the amount of oil delivered. A small alteration to this thickness can make a big difference to the amount of oil delivered. My advise is to stick with the standard sized spacer. Ive only told you about this aspect of the pump to help your understanding."

Steve then goes on to say that he has had 2 of these lubricators on his engine which has done over 200 hours with no problems.

Hope this helps

Mott

[Deleted]

Mott, thanks, that's very helpful. I hadn't appreciated that the O-rings and ball form a vacuum that sucks the oil in - I was wondering how enough viscous steam oil could get through the tiny holes in the pump body. I'll leave the setting well alone!

Regards, John

[Jason]

Hi Mott

Thanks for going to the trouble of typing that up so we all can have a read, and most interesting it is.

Cheers

Jason

[markt]

I bought a couple of identical lubricators from steamfittings. The first i bought already assembled and the second i bought as a kit i put together myself (to all you real model engineers out there i know that's cheating By assembling it, it gave me a better understanding as to how it worked. No problems with mine either.
Mark