JULABO LH 85 High Dynamic Temperature System - Manual (Page 22)

Operating controls and functional elements
22
4.1. The Presto Plus principle with closed external system
Operating:
The operation of the temperature
system and the indication is
effected via the local control
panel (2) and the removable
operating device RD(4).
Filling :
First connect the external
consumer. The menu option
>Mode< is set on >Fill<. The unit
is filled at the hinged filling funnel
(5) via the internal reservoir (5a).
The bath liquid spreads from
here into the external reservoir
(16a) and into the heat
exchanger (20).
e.g. double-sided glass vessel
The filling pipe (25) represents narrows. Therefore the filling should be done slowly. The air from the
heat exchanger (20) escapes via the venting valve. In a first step approximately 2,6 liters of bath liquid
is filled in until the level indication
indicates 3 or 4 batons (see –Filling volume- page 29). Then, by
pressing the key an automatic filling and venting mode with activation of the circulating pump
(23) is started. In intervals the tempering liquid is pumped via connection (14) into the external system
(33) and led back into the heat exchanger (20) via connection (13).
At the end of the filling process the
menu option >Mode< has to be set on >Sys close<.
Working:
In case of a closed external system the filling pipe (25) remains open and allows a change in volume
of the bath liquid caused by temperature during operation. In case of emergency it has to be possible
that the expanding bath liquid can drain off at the overflow (15) into a suitable vessel. If necessary the
external reservoir (16a) can be mounted at connection (16).
The temperature system can be cooled with air (32) or water (31). Connect the cooling water to the
lead in for cooling water (18). Lead the outflow for cooling water (17) into the locally provided drain
respectively backflow.
The temperature system is started with the key . The heating (21), the cooling aggregate (22) and
the circulating pump (23) start according to the desired adjustments at the operating device RD (4). In
the line to the pump exit (14) the pump pressure (29) and the actual temperature of the internal control
sensor (28a) is permanently measured. If the temperature control has to be effected externally a
Pt100 external sensor (28b) has to be connected and switched over to external control at the
operating device RD(4).
Safety:
In the internal reservoir (5a) there are the level sensor (26) as well as a safety sensor (27b).
The safety sensor (27a) as high temperature protection is located directly at the heater (21).
If the external circuit is interrupted (e.g. with a shut-off valve), an emergency circuit is maintained via
an internal Bypass (30).