Hello all,
After a few successful runs through my new reflux column I thought I'd post here regarding the end result. Hopefully I'm not telling people something they already know! Sorry if that's the case. The reason I chose this path is because I intend to automate the rig, and temperature control seemed simpler than accurately measuring flow, and being able to accurately adjust the flow. This is my second attempt at this type of device, the first was ok, but the internal tubes of my previous RC we too large and too few.
My RC is overkill by normal standards, in order to get a smaller variation in vapour escaping per coolant degreeC. Its 400mm long, 3" jacket with 6 x 1/2" internal tubes.
I run a recirculated coolant via pump and radiator, controlled via a simple thermostat accurate to 1C. IE: it over/undershoots by about 1C from the target, but sometimes a little more. This turned out to be a bit less than ideal. I got some surging on the output, and increments of 1C weren't incremental enough. 40C virtually no flow, to 43C decent flow but not quite right. It worked ok, but I'd like more gradual control. So to that end I'm upgrading the thermostat to PWM power control of a 12v thermofan on the radiator. I'm using the micro-controller that will be used for the entire rig so it's no extra expense. Just a bit of programming to get the algorithm sorted.
I'll report back on the effectiveness of the new temperature controller when I run it again. Hopefully it will be accurate to 0.1 of target.
Cheers all