Mornin chaps-
Ive been working on another, smaller monotube boiler.
This time with the aim of being able to drive a decent sized engine (d10 or similar) with a minimum of fuss, controls and hassle. And be easily convertable to radio control.
This is the prototype-
Its a double layer, counterflow version of the previous design. Still got 23 feet of pipe, but in half the space. Cold water feed to the top double loop layer, steam from the bottom triple loop layer, and another camping gas stove as the heater.
Heres the test rig-
Boiler, 100:1 mfa como pump motor, 1/4 inch ram pump, and a twin cylinder single acting piston valve engine.
It worked, but was a trifle wet, and still had 3 valves to control it during startup and run and shutdown, which was a bit complicated. Ok for a straightrunner but rubbish for RC as none of them really acted as a throttle.
So i designed a steam separator/ water trap/ throttle / bypass unit that does everything with just one valve.
And it seems to work, hurrah. Totally throttleable, single valve control of a monotube boiler that doesnt send slugs of water to the engine, just steam. Still needs a load of work cos i threw it together in a bit of a rush out of more bits from the spares box.
Vids-
First test, before making the separator-
https://www.youtube.com/watch?v=_rFd2lG_PIkTest of the separator and throttle valve.-
http://youtu.be/h4ErAfMiQMgHeres the basic plan for the separator, but i think i neglected to draw attention to the hole in the bottom that goes to the outlet valve. It needs to be really small. I used a 0.5 mm drill and it seems to work. You can set it up so it automatically purges the tank of water at the same rate it fills up, without losing steam pressure. I made mine from an old spirit lamp from a junk shop. Its made of chunky turned brass, and i silver soldered all the connections, as it runs at boiler pressure, but obviously not in a flame. Good idea to hydrostatically test it first....
And heres the system flow diagram. Mine actually includes a safety valve as well, its on the steam separator, and blows at 80psi.
Cheers!
Rich.