Closed Cooling Circuit - Bosch Rexroth PS6000 W Serie Anwendungsbeschreibung

R911370699 | PS6000/PRC7000 with water cooling Bosch Rexroth AG 25/35
Cooling circuit
 Oxygen in the water may have a negative effect on the chemicals added for
treatment (e.g. precipitation).
 Working temperatures of below 60°C promote algae growth.
Measures need to be taken to eliminate problems in closed water circuits. A
mechanical treatment by filtering alone is not sufficient in most cases. In addition
to a chemical treatment of the water or the use of a stable heat carrier,
constructional measures during plant design need to be taken as well.
The purpose of water treatment is to ensure:
 Corrosion can not occur anymore.
 Algae growth and sludge formation are prevented.
 Particles loosened from incrustations and sludge are filtered out.
On the part of the system, it has to be ensured that the circuits are ventilated
thoroughly and further contact with air or oxygen is avoided to increase the
service life. Thereby are all in this cycle involved components and equipment
as tools and processing plant to consider.
The electro-chemical processes occurring in a cooling system have to be
minimized by selection of the materials and the conditioning of the coolant.
Therefore mixed installations, i.e. the combination of different materials such as
copper and alloys, iron, zinc as well as halogenated plastics (PVC tubes and
gaskets) must be avoided or limited to the absolute necessary minimum.
The coolant is guided through the PS6000 or PRC7000 weld timer, the PSG xxxx
welding transformers and the components needed for heat removal as well as
through external components.
A chemist on site has to recommend suitable additives depending on the water
quality.
To provide an overview, the following cooling circuits will be described.
5.1.1

Closed cooling circuit

The cooling circuit is closed (no penetration of oxygen) and is equipped with a
pressure-relief valve; it is always connected at the suction side of the pump.
The coolant is only guided through the lines and components necessary for heat
removal, refer to Fig. 1.
The water is used permanently in a circuit. In contrast to cooling in an open
circuit, the cooling water is circulated in a closed system and the heat is
discharged indirectly via the heat exchanger. Since there is no evaporation, no
thickening and thus no losses by evaporation and desalination will occur. The
closed system principally entails no losses so that it can be operated efficiently
with demineralized water.
The materials used in the cooling circuit correspond to the recommendations
given in Section 7.