A Weir Steam Pump

[cnr6400]

Hi Chris, do you have one of those Dremel engravers? the ones I mean are for engraving initials on tools and things. Anyway, these can be used to engrave a cast like finish in pockets and recesses on machined parts. If you work back and forth one way, overlapping to cover the whole surface, then do the same at 90 degrees to the first pass, it can produce an effect very much like sand cast metal. Just an idea. I find doing this op relaxing after doing more mentally strenuous machine ops earlier in an evening. 

[crueby]

Hi Chris, do you have one of those Dremel engravers? the ones I mean are for engraving initials on tools and things. Anyway, these can be used to engrave a cast like finish in pockets and recesses on machined parts. If you work back and forth one way, overlapping to cover the whole surface, then do the same at 90 degrees to the first pass, it can produce an effect very much like sand cast metal. Just an idea. I find doing this op relaxing after doing more mentally strenuous machine ops earlier in an evening. 

I've done things like that in the past, used a little air powered rotary tool that takes dental burs. For this one I'm thinking of using a airbrush style sandblaster that has a small pattern, so it will get into small areas. Same that I did on the engine block of the Stanley. Doesn't do the deeper pits and roughness, but more of a matte finish which looks like a scaled down cast surface.
Or, may leave it like it is. Not totally sure yet.


 

[crueby]

With the main structural parts shaped, time to start on the moving parts. Started with the reversing valve rod, which is a straight rod, threaded at the bottom end and notched down near the top end to hold the valve slider. The slider is held in the notch, and all the travel adjustment is at the bottom end.

Here it is fitted to the reversing valve chest - the top/bottom plates on the chest hold o-rings to seal around the rod.

And fitted back on the pump, also made the post that the reversing arm hangs from. The pipework on top of the pump is just set in place for now, till the final length of the valve rod is determined and the rod trimmed back - rather start oversize than come up short.


Then made up the piston rod, which doubles as the pump ram. Its interesting that the piston rod is such a large diameter at the top end, much bigger than a normal double acting engine would be, but this way it reduces the volume under the piston, which reduces both the force and the amount of steam used to raise the piston and draw in water - its not doing anywhere near the work that it does on the downstroke, and they took that into accound. I think steam hammers are set up the same way.

The piston set in position - there is an o-ring between the plates at the pump end as well as at the base of the cylinder to seal it. I also am adding o-rings at the base of the piston head and on top of it, to cushion it slightly in case it over-runs the normal travel when starting up dry.

Just got the two valve faces (one on the main cylinder, one on the reversing valve) lapped smooth, so I can start on the valve sliders. Both of them are normal d-valve style. I dont want to use brass on the sliders, since the faces are brass, so may use either bronze or stainless steel, will see what size bar I have that is closest.

[cnr6400]

 

[gary.a.ayres]

Beautiful!

[crueby]

On to the fiddly-bits for the pump - milled the valve sliders out of some bronze bar, here is the reverse valve slider set in place

Then made the shuttle bar for the main cylinder valve. This dumb-bell shaped bar acts like a double ended piston, and gets pushed back and forth by pressure sent from the reversing valve, moving the main cylinder slider to send the piston up and down. It acts like a wall light switch - nothing happens till the reversing valve gets moved far enough, then it snaps the main slider over to the other end of its travel, sending the piston the other way.


shuttle in place on the slider:

and both installed in the steam chest - the shuttle goes through the hole in the end of the chest, then the slider slips on over the narrow part. A cover at either end of the chest seals up the hole.

A view from the end of the chest, showing the end of the shuttle and the ports that bring pressure from the reversing valve. As pressure is sent to one end of the shuttle, the other end is opened to the exhaust to let it get pushed over. The ends of the shuttle are stepped in, so that the shuttle can't plug the hole if it goes all the way across.

Down to the final few parts - the reverse lever which takes movement from the piston rod to the reverse valve rod, gaskets for the steam/pump chests and covers, and a steam inlet pipe and valve. Should have first movement in a couple days!
 

[cnr6400]

 

[crueby]

[crueby]

The reversing arm was milled out of some flat bar, and the slot in the piston milled through. Since the arm tips as the piston moves, the slot has to be angled from back to front. So, milled the narrow part of the slot vertically, then tiipped the mill head each way to do the angled portions.

Parts test fit, all looks good. Hard to move the piston since there is not much to hold onto, no flywheel or crankshaft to grip onto, but the throw seems to be good.


And added a threaded block to hold the steam valve - I prefer to use a valve at the engine to control flow, and let the compressor just send higher pressure like a boiler would, it tends to give a better slow running engine.

All thats left is to make the gaskets, and tighten everything up for a timing test!

[steamer]

Oh that's a cute little pump!!    Coming along nicely!     Steamer wants big vroom!.....

[tghs]

I think we need to pay a welfare visit,, me thinks the elfs have the shop master confined to the shop with an ankle chain (he is making the rest of us look really lazy)

[cnr6400]

 

Earlier this week I mailed Chris a virtual cookie with a file in it, thinking the shop elves may have chained him to a bench, similar to your train of thought.  (Files in cakes went out of style with the 3 stooges)   

Little do the shop elves know that Weir pumps can deliver very high force spurts of water capable of serious elf motion inducement! They may have forgotten the pressure washer hose incident (known as the shop elf tilt a whirl ride).

   Just joking, looking forward to the test running report and video! 

[Don1966]

Damn Dog how did I miss this one, boy an’t no grass growing under your feet. Geez another great project.....



 
Don

[crueby]

Thanks guys - this has been a very fun project!


CNR/tghs, the file in the cookie was a great idea, but the elves danced with it just out of reach of my chain, ate the cookie, and tossed the file behind the cabinet....        I eventually got the chain into the mill vise and cut myself loose...

But, it was worth it! Its a runner!  Am uploading a video to youtube now, will post the results in a few minutes. In the meantime, the elves are making a showerhead for the output pipe...  And you are right, if I block the output tube with my finger, it will squirt water a long way, just like playing with a garden hose!
 

[crueby]

This morning/afternoon I got the gaskets made for the pump, and started testing it to get it to run. At first, no luck, seemed to be leaking really badly somewhere. I traced it back to the gasket on the main valve face - there is a passage next to the slider that takes exhaust from the reverse valve chest and runs it out to the main exhaust on the cylinder side. When I made the gasket, I had connected that passage to the main chamber rather than keeping it seperate. Whoops!  That just ran steam straight out the exhaust. Once I realized that goof, made another gasket and reassembled, and things started to move. Then it was just a matter of figuring out the timing on the valve rod, adjusting the nuts up and down till it ran by itself.
So, first a couple of pictures:





And then a couple videos of it running - it is sitting in a tray of water about 1/2" deep. It actually primed itself after a few strokes the first run, so the check valves must be sealing well. Here goes:

<a href="https://www.youtube.com/watch?v=mxoGmxfvNX0" target="_blank">http://www.youtube.com/watch?v=mxoGmxfvNX0</a>

<a href="https://www.youtube.com/watch?v=alJvcBV_H-U" target="_blank">http://www.youtube.com/watch?v=alJvcBV_H-U</a>