where would i put the temp prob outside the flask if i dont have room between the mantle and boiling flask?
1 Like
I would run the sleeve temp with the little black plug that plugs into the back instead of a probe
Do you not have a 2 neck flask? Any reason why you want to run this way?
1 Like
saw something about it in another post but it seems like you wouldnt get an accurate readout of your oil temp in the boiling flask. they were saying something in the post that only head temp matters. but im pretty sure boiling temp matters as well, i dont see any real good reason for doing this, i just read it and thought i would ask. ill try to post a link to the comment where i read this
1 Like
1 Like
1 Like
Are you running hot condenser tek?
dont have the heater/chillers i need but i have the glassware for it
i have 1 recirculating heater, and currently using water and dry ice for condensing
I know someone who runs that way and seems to like it, i have yet to try it. Irs nust like autopilot when im setting up. The glack plug in the back i have heard from many sources that it doesnt work, i tried just to clean some glass ware and it performed horribly.
Every one I’ve encountered works fine. Just not telling you temps inside of flask
Flask will never get hotter than mantle being co trolled externally so no worries about what’s temp of oil in flask …all that needs known is its less than the constant outer temp of mantle…
Constant temp of oil in flask typically required delayed pid response and resulting overshoot can be bad for goal products at best, and dangerous at worst given the lack of limits on the heating coils on some larger Chinese mantles
1 Like
Old thread dredge but had an across international mantle that would overshoot by 30c each 10c increment. Called up engineer and they helped manually change programming. Pretty easy to get walked through it
1 Like
I like the idea in this post of securing the thermometer on the outside of the flask. The hottest part of the mantle seems to be about halfway up the heating bowl so I try to get the thermometer down there.
It helps prevent overshoot and allows an operator to set it and forget it a bit more easily
1 Like
Agreed, in the flask you have to go up in 5c increments or it overshoots. I use a thermometer in flask, mantle probe under flask, temp probe at head. I also attempted to “train” the probe in oil but if i went past 5c increments ie 10c at a time it would still overshoot by 30c until I asked an engineer to help redial in the settings on the mantle.
3 Likes
I typically calibrate my mantles monthly to try and avoid temp issues. Still happens from time to time. Calibrating in an oil bath gave me best results for my AI mantles.
2 Likes
every single reaction, crystallization, distillation or any procedure that anyone here is running in an electric mantle should include a wire probe between the RBF and the electric heating mantle, without exception. There is effectively no reason not to do this, and the value (information and heat control) added is worth that $2 probe.
Outside probe can be used to visualize your overshoot (how much hotter is the outside of the mantle vs inside of mantle), ensure you aren’t temp shocking your glass or product (you don’t want a delta T of >50C under ideal circumstances, altho it does happen)and allows you to actually control the temperature that the outside of the glass is actually be subjected to. There is literally no scenario in which including an external probe will not be of some value, even if only for an additional point of reference.
4 Likes
Our mantles have an external and internal thermocouple. The internal probe is buried in the insulation. The advantage is also that by placing the probe closer to the heating source the responsiveness of the heating will be much faster. When the probe is in the oil it is basically in the coldest area furthest away from the heat source. That causes the response to be longer which results in the pid being less accurate and prone to overshooting.
3 Likes