Crosshead pumps

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wbarbe
Posts: 299
Joined: Fri Jan 10, 2003 12:03 pm

Crosshead pumps

Post by wbarbe »

I was looking at a Facebook page about 1800’s locomotives and I saw that UP 119 had crosshead pumps but also had a separate check valve for an injector about half way down the boiler and I wondered, if you had two cross head pumps could you plumb them to the same check valve and use the other side for an injector? I know many RRSC 4-4-0’s have crosshead pumps on both sides. If you wanted to add an injector would you have to lose one pump or could you just plumb them together?

Anyone ever tried this? Thanks
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Builder01
Posts: 726
Joined: Mon May 18, 2015 5:26 am
Location: Erie, PA

Re: Crosshead pumps

Post by Builder01 »

It is completely possible to have multiple pump/injectors feeding a boiler at a common point. The requirement is to have a check valve at the discharge of each item, and/or before the point where they are all "teed" together.

I have a steam pump, injector, hand pump and axle pump that feed my boiler all at a common point toward the top front of the boiler. In my piping scheme, I have to remember to close the axle pump by pass valve when using the steam pump! Also, this piping scheme allows use of the hand pump to prime the axle pump if needed.
daves1459
Posts: 279
Joined: Mon Jun 07, 2010 7:58 pm
Location: Plainfield, Illinois

Re: Crosshead pumps

Post by daves1459 »

I have two crosshead pumps and an injector my Disney 4-4-0 piped just as you describe. Both pumps feed the boiler through the left side check valve and the injector feeds through right check. With the right driver crank 90 degrees rotation ahead of the left crank there is a period during each revolution that both pumps are feeding the boiler at the same time. The two pumps together will over fill the boiler. So, I installed recirculating valve under the cab floor. With the valve just slightly cracked open the amount of water fed to the boiler is about equal to amount of steam taken out. With this set up I use the injector mostly to replace steam released through the safeties while standing.

Dave
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Dick_Morris
Posts: 2841
Joined: Sat Jan 04, 2003 2:09 pm
Location: Anchorage, AK

Re: Crosshead pumps

Post by Dick_Morris »

My RRSC CP-173 uses two check valves, one on each side, that have a proper period look that I got from Gene Allen many years ago. The two crosshead pumps and their bypass are piped to one check and the injector to the other. That seems to work fine. I didn't have a lot of money for castings at the time I built the locomotive, so the pumps are fabrications, made to the RRSC outline. I started with one, but with a 1/4" ram it didn't have enough capacity so I added another.

I prefer using the injector, especially at higher boiler pressures, as the resistance of the two pumps on adjacent power strokes makes the locomotive jerky when the bypass is fully closed.
wbarbe
Posts: 299
Joined: Fri Jan 10, 2003 12:03 pm

Re: Crosshead pumps

Post by wbarbe »

Thanks for all the information. I figured it should work.
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