Greetings,
I am hoping to gain some help in selecting some components. We have a home made vac oven comprising an old electric skillet and its corresponding temp control dial. That dial has quit working with any semblance of “control.” It is basically a crapshoot as to whether it holds any temp or just keeps heating the skillet.
Our problem is the frankensteined setup doesn’t give much chance to “replace” the skillet without destroying the rest of the rig. So we thought we might try to build a temp control system that senses the temp in a liquid used to insulate the vac chamber and when temp is reached turn off the skillet control at its wall plug.
Obviously a simple relay between the wall plug and the wall will handle that but what we are hoping to get some help selecting is the temp sensor and control device that would allow triggering of the wall plug relay setup.
I found the TC4-M1 device but it is ambient environment only and doesn’t have any external sensor capability. We could build our own rig for this but I stumbled on this site and am hoping one or more of the folks here might offer a suggestion or two on components to speed up the process. We are in a bit of a time crunch relative to sample runs with the vac oven. And, of course, since we are using a cobbled together vac oven, we are on a restricted budget as you might imagine.
Thanks for reading this and thanks in advance for any support or suggestions.
Martin
What temperature range?
Thermocouples are the most versatile temperature sensors, but require an amplifier. On the other hand, self contained thermocouple PID temperature controllers have become ridiculously cheap, and would solve the problem. Those with an SSR easily handle 1000 watt AC loads.
http://www.ebay.com/sch/i.html?_nkw=the … mfe=search
Jremington,
Thanks for the reply. Sorry about the delay in responding. Seems I am not getting alerts that my post was replied to… not even sure if I should be but I was relying anyway.
So, the temp range is relatively low at this time, in the 85 to 115 range. We are compounding organics and using ethyl alcohol as a delivery/segregator and then need to vac it off over a specific temp range.
We are pretty close to just tossing in the towel on the rig that was cobbled together over the last few months as we prototyped and refined the process but there is a certain familiarity and attachment to it that makes us reluctant to toss it when we know we could solve the problem with an external thermo setup. We just don’t know where to find the easiest to use parts.
We found that one-wire thermocouple and thought that would be great cuz it was rather cheap, but then realized we would need to mount IC chips, program same, and deal with a bunch of other stuff. We are organic chemists, not electrical engineers… Although we are obviously willing to cobble stuff together, there is a lack of knowledge on what would be smart both in the sense of cost as well as ease of assembly.
Those PIDs you linked me to will do the job nicely if I can figure out the right one. A few are pretty darn cheap and make the fabrication of something unnecessary. We will fetch one of those and go from there.
THANKS!!
Martin
FInal update…
Gotta admit, I feel kind of silly not having been able to figure out that the TC4-M1 device was a huge clue/lead into finding the almost identical REX-100 PID. Having acquired a REX-100 PID and run two batches over the weekend, we are back in the flow of running sample compounds and getting much better temp control with that PID vs the previous method of using a candy thermometer to “prove” the widely unpredictable skillet therm. We aren’t sure yet, but the first two batches actually look like they have gained desirable aspects from the more consistent and accurate temp range. We will see when we get the “cracklins,” as we call them, blocked and under the microscope.
thanks again to jremington specifically and to anybody else who might have read my init post.
And as an aside, I have ordered a couple of the kits found on this site for my kidlets(and me) to play with. GREAT STUFF!!
Martin and crew(and kids).