12" Southworth pump question

Good morning folks.

I have a rather troublesome 12" Southworth pump in my 16 ft steam launch.

I obtained the pump from Keith Appleton (Mainsteam) and it was superbly made by Don English, so I have no doubts as the the quality of it.
I am sure that the problem lies with OPERATOR ERROR.

The pump can be very erratic in use.

Sometime it will work perfectly and then all of a sudden judder and stop or just stop.

Sometimes it sounds like the pump it not completing a full stroke properly.

It has been suggested that there is an air lock.

I know nothing about these pumps so wouldn't know where to start !

There are no drain cocks fitted. I added a drain cock to the steam line adjacent to the steam chest to help remove any condensate.Apparently Southworth pumps rely on seepage through the glands to drain. Mmmm ?

I have fitted a displacement lubricator.

Any advice gratefully received.

Fortunately I do have two other methods of getting water into the boiler !!!

Many thanks.

Ian

Greetings Ian, although I have no experience with the Southwold range, I have built a number of this type of pump, as well as operating the "full size" versions.

I would say that they all can behave as you describe, but the biggest single item that does need care with single cylinder pumps is lubrication. If your lubrication system is OK, then look elsewhere, but i have found that lubrication on the steam side to be very important for reliable running.

Regards

Brian B

Thanks for that. I’m pretty sure the lubrication side is ok. As well as the displacement lubricator there is a mechanical one that feeds the cylinder.
I will be pulling the boat out of the water next week so can investigate at my leisure.
All part of the fun

I have a steamboat buddy who is an extremely competent engineer and he has the same pump, totally relies on saturated steam to lubricate and never misses a beat !!!

Here's a link to a video of my pump

**LINK**

Ian,

I have built my variation on the Southworth and run it this season on my steam lorry at 160 psi. A few bits of experience I have gleaned:

• Include a bypass in the pump delivery line. That way you can get it warmed up on "no load". Makes life a lot easier.
• Mine is run on highly superheated steam (300 C+), so relies totally on the mechanical lubrictor. I had to adjust the Ewins element on this up to max delivery and put a fan tail spray on the oil delivery. Initially, the internals were dry after a run (too little oil), and what oil there was all seemed to disappear out of the valve rod gland - hence the need to "spray" the oil in.
• I have included 3 auto drain cocks (1 on a longish feed line, 1 on each end of cylinder). The free ball in a chamber type that are quite popular on smaller loco cylinders. I am not convinced they do much but they do no harm either. Incidentally, they don't really need drain cocks. They will run quite happily on pressurised water, which is what they do to get rid of condensate - they can only do this slowly though. The water will end up in your hot well, not the bilge.
• I always run the pump on air after a steam run, as my cylinder block is cast iron (as were Weir's). This blows out the condensate and gets plenty of oil in.
• Being cast iron, the shuttle valve still has a tendency to stick, so I have put two little plugs on the caps at each end. Remove the plugs, poke in two small screwdrivers and waggle the shuttle about a bit, replace plugs, open to steam and away you go.

The pump will run very evenly on air against no load (just like KA's example). On steam, even when warmed up it takes a few strokes to get into it's stride when you open the steam valve, but once properly warmed through is OK, but never as even as on air. I think this problem is likely to be more marked for you as a boat is unlikely to be running the superheat that I have.

An ex engineer on the Waverley tells me that they can be temperamental in full size. He recommends opening the steam supply valve when you light the fire and just let the pump warm up with the boiler, you will soon know when the pump is running from the "clonk - clonk". I have tried this approach and it certainly has some merit.

My modifications to the design were driven by two thoughts:

• As drawn it is a symphony of leaks conducted by 6BA bolts. It needs to be far more rugged to be a reliable boiler feed on boats (or steam lorries). If you think I am fishing for 6BA bolts in a filthy bilge or roadside verge - think again!
• As drawn it is not a Weir. The Weir was distingushed by the horizontal shuttle that incorporated a piston valve and distinct absence of extra ports and drillings.
• A bronze cylinder, piston and shuttle is not going to take kindly to highly superheated steam.

You can see more detail about the pump on my Flickr pages of the steam lorry build here:

**LINK**

The Weir pump album is 2 row 3rd from left.

Hope that helps, PM me to compare notes if you wish.

Martin

Hi Martin.
That’s going to be a great help and I will digest it later.
I have just come back from a 4 hour steam trip where amazingly the Southworth performed faultlessly.
It must know I was that I was “on the case”.
Will get back to you later.
Thanks again.
Ian

Where's the viaduct, Calstock?

Indeed it is

My mooring is adjacent to the viaduct

Martin.
That’s been an immense help.
A long warm up and using the bypass I already had installed enabled a faultless 4 hour steaming today.
Also reducing the amount of steam in and restricting the exhaust a bit has provided a nice steady beat.
I think I have it cracked !!!

Thanks again.
Ian

Glad to be of service, Ian. I have not yet tried restricting the exhaust, but I read that you can explore really slow running with it. Thats a bit tricky to arrange a control in the cab!

Martin

Martin.

BTW. Keith Appleton doesn't agree with restricting the exhaust, but it does work !!!

Thanks again.

Ian