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 I’m 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.