Heidolph ROTACOOL Betriebsanleitung Seite 15

Minimum operating temperature: The viscosity of the thermofluid increases at
low temperatures. This impairs flow and reduces heat transfer. Viscosity should
therefore be as low as possible and should not exceed 120 mm²/s.
Remember that many thermofluids are hygroscopic. The air humidity to collect
in the thermofluid will form a layer of ice on the surface of the evaporator which
will impair heat transfer. At temperatures below room temperature in particular,
the filling apertures should be sealed with the cover I. The water to accumulate
in the thermofluid must be evaporated off from time to time, if necessary.
The following substances may not be used in the bath:
•
Cooling liquids which contain additives such as ethers, esters and
amines (which are contained in some glycolenes)
•
Demineralized or distilled water
•
Mineral or sea water
•
No CaCI
The bath for the cooling liquid for the circulating chiller has a capacity of approx. 2.5 l.
6. Tube connections
Screw the connections for the cooling liquid (A) to the threaded sockets (B) using an open-
ended, 19 mm spanner. To connect the condenser of the rotary evaporator to your circulating
chiller, you will need a tube with a nominal width of 7 – 8 mm for both the advance and the
return. Connect the tube for the advance to the left socket (D) on top of the appliance and
make sure it is leak-proof. Connect the return to the right socket (E). Protect both tubes
against inadvertent slippage using hose clamps. If you want to work with advance
temperatures in excess of 5 to 10 K either above or below the ambient temperature, these
connecting tubes must be thermally insulated as well.
To ensure the proper circulation of the cooling liquid, make sure there are
no kinks in the connecting tubes.
7. Filling the cooling liquid
Only an externally closed system can be connected to the rotary chiller. Shut off the
discharge valve (F) (so that the slit is vertical). After removing the cover I, fill the system
through the filling aperture up to approx. 1 cm below the overflow hole (T) in the filling gauge
(G) Aerate the condenser of the rotary evaporator by switching on the ROTACOOL at the
On/OFF switch (H) (press the switch and the control lamp will light up to confirm operation).
The circulating condenser aerates itself via the built-in expansion vessel.
During operation of your circulating chiller and when using a large
capacity condenser (e.g. condenser G4) the level of liquid in the filling
gauge (G) may fall so far that the cooling liquid level switch responds and
stops the circulating chiller. Top up with the cooling liquid. (See Chapter 8
„Discharging the cooling liquid").
8. Discharging the cooling liquid
Remove the screw-on cap (I) of the discharge socket (J) and slide a tube with an inner
diameter of 8 mm over the discharge socket (J). Secure the tube to prevent inadvertent
slippage. Hold the other end in a collection vessel and open the discharge valve (F) (so that
the slit is horizontal).
brines as these destroy the high-grade steel material 1.4301.
2
open
F
closed
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