Steam pump

Hi all,

I have just made a worthington single type steam water feed pump and it works a treat until it goes under pressure when on the loco.Any ideas what the problem could be?

Cheers

A stuck clack valve at the boiler end?

Chris Gunn

Duplicated

Chris Gunn

Edited By Chris Gunn on 29/03/2017 22:06:34

No checked the clacks and pipework blockages,Glands were leaking so repacked them ,just need to test again.

When i tried it last week it would pump twice then stop,wait a minute or two and it would start n stop again,strange.

The Stuart steam pumps are famous for not working, simply because, as designed, the steam piston covers the drain cock hoes before the end of the stroke, and you get a hydraulic lock. A small groove between the drain hole and the end of the bore, at both ends of course, fixes it. Could yours be doing something like this?

Maurice

Ah yes

There are no drain cocks at all in this design.

cheers

Exactly which drawings /design have you used?

It works ok on air with the water side not connected to a pressure valve/pressurised vessel?

It works ok on steam with the water side as above?

It doesnt work on steam when water side connected to the loco boiler?

Where is the pump situated on the loco, and how long is the steam pipe to same and from where on the loco?

What is the bore of the steam side cylinder compared to the bore of water side cylinder?

What does the steam exhaust look like when running on steam on the loco?

Cheers,

Julian

Hi Julian,

Drawings were from Allen models in the US

No idea if it works with the water side disconnected and connected to pressure vessel(Good point and would answer your next question).

IT does work under steam all connected but only pumps a couple of times stops and after a minute restarts only to stop and the cycle goes on.

Pump is at the front of the loco about 14" from the steam valve

Steam cylinder bore is 1" water is 5/8

Cannot see the exhaust as it is piped into the smokebox.

Hope this helps and thanks for taking time to help me.

Del, could that be the correct way it operates? It is getting water into the boiler presumably, if it were running continuously you might soon fill up the boiler with a pump ram that size. The water pump piston is 5/8" which seems pretty big to me, my 4" scale Garrett has a 5/8" piston feeding a much bigger boiler. Is there a restriction on the steam feed? it seems as if the pump will go when pressure builds on the steam side or water pressure drops on the pump side?

Chris Gunn

Del just had another thought or two, can the water get into the pump OK? Maybe obvious but are any of the pipes blocked with PTFE tape or a lump of silicone sealant for example?

Chris Gunn

Chris,

All lines are clear,i am trying it again tomorrow so will report back.

cheers

If the steam supply were taken off the turret/manifold then fed through a hollow stay through the boiler to the smokebox then to the pump, I think you would find the pump will work. This, of course, wont be possible with a boiler without a spare hollow longitudinal stay, though you could swap the blower feed for same if it goes through a longitudinal hollow stay. The blower could be run off the manifold outside the boiler though you will get water up the chimney when first turned on.

The 14" long steam supply to the pump outside will definitely cause the steam side of the pump to be water logged due to condensation. This is the cause of the problem commented upon by others previously.

I doubt if lagging the steam supply pipe will help.

Cheers,

Julian

Having seen the dramatic change to the performance of my Stuart pump, once I was able to drain the cylinder properly, I still think you should fit drain cocks if possible.

Maurice

I found that running the blower pipe on my locos right next to the boiler (touching if possible) under the lagging gave a dry blower, might be worth trying with the pump. One loco in our club which has external exposed blower pipe has a fountain going up te chimney most of the time.