Rotary Evaporator Troubleshoot

CannaBusiness
1

Hey everyone,

I hope someone can help me identify the issue. I’ve spent the entire day taking my 50L Rotary Evaporator apart and I can’t locate the issue.

It seems that the system is struggling to maintain a vacuum. The odd part is that it can hold a vacuum (around 0.095 MPa) as long as the boiling flask is oriented a certain way. If I rotate it 180°, there is an audible leak and pressure quickly increases back to atmospheric pressure.

Does anyone have any suggestions? I took out all the gaskets, changed them, greased everything, and the problem persists.

2

What direction does it hold vac?
The problem is somewhere in your rotery seal.
Ps: Dont use grease in a rotovap rotery seal, the etoh might not dissolve it, but other solvent like hexanes will eat it. Thats product contamination just waiting to happen.

3

I had mine leak at the condenser and motor. Took me 45 mins to figure it out.

Reposition, retighten, recheck

2 Likes
4

The point at which I insert the rod from tightening is when it holds vac. 180° after that is the leak.

5

You sure it’s not the seal between the evaporating flask and motor? If you leave that overnight with product inside the weight will warp the seals and cause such a leak.

2 Likes
6

I’ve changed it out with different gaskets (in exception of one) and was unable to fix the issue. It may be that single gasket and will be the next thing I replace.

7

This can also be caused by a defective vapor tube which I observed with smaller units. If the vapor tube is not 100% straight it can warp the gaskets while at certain rotational positions while working fine in others. I had this problem when buying replacement parts from Ace but with ones from the original manufacturer it worked fine.

8

I second @goldleaf_scientific , check the seals near the motor, try helium testing.

9

I know the location of the leak. I am having issues locating specifically what is causing the leak.