Cannibalizing the Ebullator

I’ve moved on, in regards to what I think can be learned from the first flooded evaporator system, I have been calling “The Ebullator”.  Far too many limiting features were preventing me from moving on to the next step in my research, and the modifications needed would not have been worth the effort.  I chose to dismantle, and harvest the copper for the next project:  a finned evaporator coil.

This is the last picture of the machine, before it was dismantled.  Several changes were made since the last post, including an air cooled condenser, a plastic sight glass, several embedded thermocouples, and a pneumatically controlled expansion valve.

The extended view sight glass was made with a piece of 1/2″ OD polyethylene tubing, sealed with compression fittings.  Initially, it was a great success, allowing me to understand how the liquid level changed in the separator column under various system conditions.  I found that over the course of 12 hours or so, the continuous pressure exerted by propane under ambient saturated conditions, caused the tubing to swell into the shape you see above.  I removed the charge in the system as a precaution, and sought out a higher working pressure tubing.  I ended up with some nylon tubing with a 250 psi working pressure, as opposed to 100 psi for the PE.  The nylon is a little harder to see through, but has yet to swell like this.

I acquired an R-22 expansion valve, rated at 1/4 ton, and proceeded to cut the sensing bulb in such a way as to control the pressure on the power head with an air pressure regulator fitted to a small air tank I assembled.  I found this to provide easier control of throttling for the device.  Although I did not try utilizing the sensing bulb as it was intended, it was unlikely to function correctly, as the evaporator is designed for a flooded condition, and the suction gas is in a saturated state.

Here you can see an “exploded view” of the system, after I dismantled it.  The evaporator unit itself was aesthetically pleasing, and would have been nice to keep, but I really could use the parts.  Out of the four coils, I have since straightened one of them, and used the copper for further developments.  I find the re-usability of copper to be fascinating and something I take pride in achieving.

The following post will provide some detail on how I have been manufacturing embedded thermocouples, to take refrigerant temperatures directly inside the lines.

-M.C. Pletcher