Hello!
I was looking to aquire/build with a mantle heating element core a mantle to heat a 500 or 1000mL round bottom flask.
I checked the ratings and rarely exceed 500W for 1L flask.
Now i wonder, how can it be so "low" in power?
even though i may sound dumb, i have various hot plates, and minimum are 1kW.
I have built also one with an aluminum cast block and heating element,. rated at 400W, and its much slower to say, boil water in a beaker.
Now am I missing something? Is the shape of the mantle significant in minimizing heat loss hence the lower rated power?
Thanks!Rainwater - 16-10-2023 at 06:36
Factor in heat loss.
How much heat is not going into your reactor vs how much goes through your reactor.
By reactor i mean rbf, beaker or whatever your heating.
The more insulation you have, the lower your wattage requirments. Sulaiman - 16-10-2023 at 06:45
Hello!
Now am I missing something? Is the shape of the mantle significant in minimizing heat loss hence the lower rated power?
Hello and welcome,
Yes, a heating mantle is much more efficient than a hotplate, especially with RBFs.
Stirring is not just a 'nice to have' feature, it is really useful,
For my diy 500ml heating mantle I've temporarily given up on magnetic stirring in favour of overhead stirring,
but either is good.
My 500ml heating mantle is suitable for neck size 24 glassware,
For solvent recovery I use my 5l mantle/rbf with my NS24 glassware, very useful,
but I was gifted it - too expensive for my hobby budget.
Choosing a heating mantle has consequences,
Rbf size determines experimental volumes,
which determines purchasing cost and volumes of chemicals,
and equipment (glassware, clamps/stands, measuring equipment (burette, cylinder, scales etc) etc.)
which determines storage space required,
and safety measures such as fire-fighting.
There are many discussions here on SM regarding choice of scale and glassware size.
[Edited on 16-10-2023 by Sulaiman]Dr.Bob - 16-10-2023 at 14:47
For heating organic solvents, which have a lower heat capacity, lower wattages are fine, especially when the filament is near the glass and insulated
somewhat. The only challenge is heating water, which is hard to do quickly in a heating mantle. But often heating mantles can provide enough heat
at 40-60 % of their rated voltage for organics, and go much higher with water. I just rarely use water for much organic work.
So 500 watts is plenty for a 500 ml heating mantle in my experience.VanUnamed - 16-10-2023 at 20:40
Oh i see, it's more efficient.
the intended use is.. indeed distilling water-like things (as in temperatures). azeotropic HCl from waste CuCl2 leachant, or nitric acid. so all
around the 100~120C BP.
