BUCHI Extraction System B-811 LSV - Manual (Page 32)

5 Putting into operation
32 B-811 Operation Manual, Version G
5 .7 Connecting to a recirculating chiller
5 .7 .1 When is it recommended to work with a recirculating chiller?
The temperature difference between the boiling point of the solvent and the cooling water temperature
should be 20 - 25 °C to achieve a good condensation of the solvent in the condenser and to keep a
good solvent recovery throughput during the extraction. When using solvents like dichloromethane or
petroleum ether, a recirculating chiller (e.g. B-740) should be used if the tap water is warmer than
15 °C.
The cooling water tubes pass mainly inside the B-811 to facilitate the instrument handling and to
protect the tubes from damages. When using tap water usually there are no extreme temperature
differences between cooling water and surrounding. Using a recirculating chiller the temperature differ-
ence between the cooling medium and the surrounding is usually higher and thereby condensation
water can be formed outside the tubes. This condensation water can accumulate inside the B-811
and affect the optimal use. To prevent an accumulation we recommend to connect the tubes outside
the housing.
The graphic below shows the connection to a chiller.
1
2
3
in out
a Connection from left con-
denser
b Outlet from B-811 to chiller
inlet
c Connection from right
condenser to chiller outlet
(see also Fig. 5.6)
Fig. 5.3: Connections to a chiller