[SEL] Thermo-syphon Question

[John Culp]

On the thermosiphon cooling system for Dolly the Listeroid I chose to 
manually control the coolant flow with a gate valve that I put in the 
BOTTOM line. My reasoning for that was that if I forgot to open the 
valve, the water in the head passages would boil, but the steam bubbles 
would percolate up the top line to the cooling tank. As long as the 
water level in the tank was above the opening of the top line, the 
water jacket would stay full of water. I made sure the line always 
slopes upward and could not have a kink to trap rising bubbles. This 
mode of operation is equivalent to hopper cooling. If a valve (or stuck 
thermostat) in the top line isn't opened, expanding steam in the head 
will push the water down and out the bottom line, leaving the water 
jacket full of steam. The engine will then overheat badly. I made a 
fitting with a closed off piece of copper tubing soldered into a hole 
drilled in a pipe plug to insert a cooking thermometer where the top 
line comes out of the head so I could monitor the temperature. I like 
to keep it at 200°F or so. It responds very slowly to changes in load. 
I don't feel a need for an automated system.

John

On Jan 19, 2007, at 3:48 PM, MaytagTwin at aol.com wrote:

>
> Hi Curt,
> If you don't want to have to monitor the temperature by hand, you might
> place an automobile thermostat in the top line.


John Culp
Bristol, Tennessee, USA