Heidolph LABOROTA 20 automatic - Manual (Page 108)

108
E
32. Fill evaporator flask
32.1 Weight sensor
The
LABOROTA 20 drive head features a weight sensor to determine weight evaporator flask
and its contents. This way, evaporator flask can be filled to a certain mass all the time and start
refill at a certain weight defined before. Weight is displayed as
„Solvent Level“, figure
displayed being relative, instead of the absolute weight in kg.
32.2. Accuracy of weight displayed
Weight displayed is a function of a variety of factors and may differ:
32.2.1. Evaporator flask weight
Depending on flask size (6 liters, 10 liters or 20 liters), weight is different.
32.2.2. Buoyancy in hot bath
Depending on flask size (6 liters, 10 liters or 20 liters), buoyancy is different.
32.2.3. Hot bath fill level
Rule of thumb: the higher fill level in the hot bath, the higher buoyancy of the evaporator
flask.
Talking about a water bath, featuring automatic water refill and fluid level control, fill
level is kept constant within very narrow limits. Hence, influence by fill level is rather
low.
Talking about an oil bath, not featuring refill mode, fill level depends on the user who is
going to fill it. Account for thermal expansion of the oil or heater fluid all the time.
Operational buoyancy will settle when reaching hot bath nominal temperature.
2 4 8