Author Topic: Southworth Engines Boiler Feed Pump  (Read 54440 times)

Offline Doc

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Re: Southworth Engines Boiler Feed Pump
« Reply #75 on: November 28, 2013, 10:17:49 AM »
Just spotted this build and I must say nicely done! I haven't done a boiler yet but am hoping to attempt one in the future. That is a nice little feed pump! Thanks for posting a build on it!

Offline alanfrost

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Re: Southworth Engines Boiler Feed Pump
« Reply #76 on: November 28, 2013, 08:07:33 PM »
Thanks Don, I was trying to work out how to include the URL in a post but the server didn't like the punctuation in the message and kept kicking me out.

Offline dsquire

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Re: Southworth Engines Boiler Feed Pump
« Reply #77 on: November 28, 2013, 09:23:31 PM »
Alan

Glad to help. Nice work that you are doing.  :D :D

Cheers  :beer:

Don
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Offline alanfrost

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Re: Southworth Engines Boiler Feed Pump
« Reply #78 on: January 09, 2014, 03:00:15 AM »
Finally got back to plumbing the pump into the boiler to attempt to get it running on real steam.  This is my first serious steam project so Iím on a steep learning curve and may be missing some essential point so feel free to provide feedback and suggestions on what I have missed.
The power plant is a PM1 boiler coupled with a PM #8 steam engine. I set up a temporary oil trap, jam jar and plastic piping, for the test.


The initial test resulted in large amount of steam exhausting from the pump but no pumping action because the pump piston suffered from hydraulic lock. The amount of condensate from the engine and pump was large and rapidly filled the separator.  The volume of condensate led me to believe that while the boiler raised steam quickly the steam itself was highly saturated.  I modified the steam line routing it directly back into the boiler head space, down into the firebox via one of the fire tubes and up and out through a second fire tube to provide a degree of super heating. This did drastically reduce the amount of condensate in the separator to that generated by the steam condensing when it hit the cold masses of the engine and pump. It did not however, eliminate the lack of pump action.
 I disconnected and plugged the steam feed to the pump and fed the pump with a regulated supply of air.  I then fired up the boiler to run the engine.  Running the pump on air I adjusted the pump stroke and speed to replace the steam consumed by the engine and ran the system for an hour. Boiler pressure was between 10 and 25 PSI during the test.
To determine the PSI at which the pump was operating compared to the boiler pressure I replaced the displacement oiler with a pressure gage. To maintain the required feed rate I used an indicated pressure of 15 PSI which gave an open valve flow at 10 PSI. You can see this on the posted you tube video.
So I have a conundrum to solve; the individual components, engine and pump, run from independent pressure sources but not from the boiler alone. The pump requires less pressure than the boiler is generating so my current thought is that there needs to be some pressure regulation of the steam feed to the pump.
« Last Edit: January 09, 2014, 03:35:18 AM by alanfrost »

Offline alanfrost

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Re: Southworth Engines Boiler Feed Pump
« Reply #79 on: January 20, 2014, 06:36:28 PM »
Finally have the pump and motor running but as usual there is more work to do. Having determined that the pump needed more of the available steam at a flow of at least 10 PSI while the engine will happily turn over with as little as 2 PSI of flow I designed and built a regulator to reduce the pressure and flow to the engine only discover that the ceramic burner I'm using only provides sufficient output to provide a flow that barely exceeds the minimum required. It is possible to get the motor and pump running at the same time for short periods but the pump was not able to replenish the boiler losses even with the burner on full and the fuel tank icing up because of the high evaporation rate. I  resorted to directing the flame from my trusty MAPP blow torch into the firebox which increased the flow rate to around 25 psi. The added pressure and flow ran both the engine and pump and the pump sustained the boiler level.  More heat or a more efficient boiler appears to be the solution. The test is on YouTube. If anyone has suggestion for a higher output heating source let me know.     

&feature=youtu.be

Offline alanfrost

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Re: Southworth Engines Boiler Feed Pump
« Reply #80 on: January 20, 2014, 07:47:06 PM »
Eureka!!! I've been running my ceramic burner on butane lighter fuel as it's all I can get locally but I finally stopped at a camping store and picked up some butane/propane camp stove fuel and wow it really burns much hotter than butane alone so I now have the pressure I need.   

Offline Steam Geek

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Re: Southworth Engines Boiler Feed Pump
« Reply #81 on: June 27, 2014, 05:00:57 AM »
I have actually got round to machining my set of castings, one thing that always bugs me on model engineering drawings is the lack of tolerance information.

What tolerances have you been machining to for your steam pumps? :nrocks:
Turning good metal into swarf