n
The flow rate of the heat transfer liquid at high cooling capacities
(> 15 kW) should be at least 40 l/min or equivalent to pump level 4.
n
When operating on a pressure-sensitive application (e.g. a glass reactor),
you must install a pressure relief device (e.g. a safety valve) in the
hydraulic circuit.
n
When determining the maximum process temperature, please bear in
mind that the temperature in the reverse flow is higher than the tem-
perature in the outflow in "cooling" operation.
The temperature difference from the outflow to the reverse flow
depends on the heat capacity of the heat transfer liquid, the pump level
and the amount of heat introduced by the application.
Set the process temperature and the overlay pressure in such a way
that the heat transfer liquid cannot boil in the constant temperature
equipment or in the application.
The following parameters must be set for the pressure overlay:
Tmax
- The Tmax value is the maximum operating temperature. It
must be at least 5 K below the boiling temperature of the
heat transfer liquid. The Tmax value is measured in the out-
flow of the temperature control unit.
Tmax_return - The Tmax_return value is the maximum operating tem-
perature. It must be at least 5 K below the boiling tem-
perature of the heat transfer liquid. The Tmax_return value
is measured in the reverse flow of the temperature control
unit. The Tmax_return value is particularly relevant to safety
at high outflow temperatures with high cooling loads.
Tih
- The temperature limit value Tih limits the input of the set
temperature.
The maximum value of Tih must be 2 K below the value
of Tmax. The constant temperature equipment reduces the
heating output when Tih is reached during operation.
Set pressure - The set pressure (Pset) is the pressure overlay which is
determined from the heat transfer liquid and the desired
operating temperature. Please bear in mind that the pres-
sure overlay refers to the relative pressure. The ambient
pressure must be taken into account when setting the pres-
sure overlay.
The possible setting range for the set pressure is 0 to 4 bar.
8.2 Menu structure of the pressure overlay
The menu structure for a device with pressure overlay is shown.
Safety instructions for operating the pres-
sure overlay
Pressure overlay parameters
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