CRTS:Rotary Evaporators
Function / Use
Rotary Evaporators (Rotavaps) can be found in almost all modern Chemistry labs. They are an essential piece of work-up equipment allowing you to recover your product post re-crystallisations or other purifying steps.
Maintenance / Basic Care
It is always good to have the appropriate size of cone on the end of the duct to prevent having to purchase too many adaptors. Most groups do not need anything larger than a B24 cone then you can set up all your glassware with only B24 and B19 sockets with the need of only one adaptor. This makes ease of use and cost savings possible.
Loss of Vacuum
There is generally only one source of vacuum leak on a rotavap if the pumping system is working efficiently and that is the vapour duct seal. These should be removed and degreased in petrol regularly perhaps once a month. This removes abrasives such as silica and reduces wear on the seal and duct. When clean, replace with a small quantity of grease on the seal which will both lubricate, reducing wear, and improve the vacuum by filling the small gap. Glass is never totally concentric.
Tutorial
Vapour Duct Removal
Vapour duct removal for the most common models in Chemistry the Buchi R111 and R114.
On all Buchii R114 models to remove the vapour duct push in the locking pin in the bearing housing then wind the combi clip up towards the bearing housing clockwise and it will come out. Clean with solvent then lightly grease the cone before pushing back in this will aid release the next time. These units only take the vapour duct with the green dot on next to the cone all others are too small.
Buchi R111 models and all previous models do not have a lock button but can be fitted with a vapour tube with a combi lock. Only vapour ducts without the green dot fit these models all others are too large.
If the duct is stuck solid then the motor housing has to be removed and the duct forced out. Best to take to the CRT to do this.
Recommended Supplier
Seals
| Model | Seal Assembly | Vapour Duct Vertical Assembly | Vapour Duct Diagonal Assembly | |||
|---|---|---|---|---|---|---|
| Part No. | Price | Part No. | Price | Part No. | Price | |
| R-111 | 000636 KD 22 | £31.35 | 017485 | £84.00 | 017484 | £84.00 |
| R-114 | 000636 KD 22 | £31.35 | 032339 | £84.00 | 032340 | £84.00 |
| R-210/215 | 048021 WD 26 | £31.35 | 048160 | £76.50 | 048164 | £84.50 |