Here is my set up for simple ultra short path distillation. This is set is basic however it works very well. Be cautious of any online retailer of short path kits. I recently sent one an example of this video - Imhad seen an online complaint about their systems not working and their reponse online to,their customer was to double check the themometer well vacuum grease! This is not ehat prevents a pull down under 100 microns lolz.
This major online retailer of "short path" distillaiton equipment has several major tech errors in their system and seems to have just thrown together a kit from a quick read of Wikipedia about short path distillation. This guy responded that I had simply installed my pirani sensor in the wrong place to achieve ¾ of a micro vacuum! Lolz, he asserted that the pressure sensor must be inside the boiling flask for the readings to be meaningful!!! He then went on to inform me from his business email account that, "... your readings are meaningless because you placed the vacuum sensor after the gas has condensed."
Well, I did not bother asking the guy to try to come up with any additional bullshit to try to explain how on Earth anyone can possibly position a vacuum sensor inside the boiling flask, but my point is that this guy posts all over the internet about distillation but ignores technical flaws in the sytems he sells, and clearly does not sell the correct vscuum system components (red rubber hose is in his kits which is contraindicated for molecular distillation and which is whynhis customers fight vacuum issues) favoring instead explanations that cannot possibly be correct. For my application the Pirani sensor is the best choice and the positioning is correct according to vacuubrand who manufactures the sensor - " ... we are unaware of inaccuracies in readings from our sensors when installed as depicted."
Be VERY cautious when any salesman selling a Welch pump with red rubber hose tells you about what is needed because he or she is locking you into a real nightmare with eternally chasing the temperatures all around and 20-50C higher than is possible with a tight vacuum. You may even be told the system works great, but it is your own placement of (fill in the blank) that makes a multi thousand dollar commitment not work.
Here is a post of how I do it. There are only a couple inches of polymer tubing to couple things then stainless steel bellows otherwise for hose. This rig proves that distillation at 140C is possible at a vacuum of ¾ of one micron.
My suggestion is to avoid the salesman selling packages and learn for yourself what is needed. I would not invest in a Welch 1400 and certainly if you see a kit with one offered alongside orange rubber vacuum hose then understand that you are being sold a real headache because it means the folks selling it to you do not understand something fundamental about the process and likely will portray their knowledge as "expert".
Both vids are the same rig but second vid had thermometer placed one inch over top of boiling puddle inside boiling flask. This temp of 140C agrees with previous measurements during other setups I have done including my traditional short path head rig (not shown).
THC boils at 140C at a vacuum of ¾ of one micron as shown in the second video.
