Installation | Operation Manual C 2214 |
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5.2.1 Overpressure pipes
Chlorine gas metering units are perfectly suitable for gaseous chlorine. However, liquid chlorine chemically
attacks the unit. Therefore the penetration of liquid chlorine into the units must be avoided. Overpressure
pipes must be run upwards in direction of the metering units. This also applies for flexible connection pipes.
Therefore the turns of the flexible copper pipes must be positioned horizontally! condensate drops may flow
back into the cylinder.
Fig. 7: Correct design of the pipes
As a result of temperature variations, chlorine gas may condense to liquid chlorine in the overpressure system.
Therefore a uniform ambient temperature must be provided. A room heating is recommended. If a uniform
temperature is not possible because of structural reasons, a pressure reducing valve has to be installed in
order to reduce the temperature at which condensation starts. It decreases the temperature, at which conden-
sation begins. If necessary, the chlorine has to be heated up using a chlorine heating block before entering the
metering unit. Here, also a heated demister may be used.
Fig. 8:
Cylinder installation
As solid lines, seamless pipes are used for overpressure piping. An internal corrosion protection is not required
as steel (e.g. St37-2 or St35.8) is chemically resistant against chlorine. Please make sure that the entering of
humidity is avoided so that hydrochloric acid cannot be formed. For connecting flexible lines, flat gasket are
used. As a result of the mechanical strain, the service life of flexible cop per pipes is limited. Accident Preven-
tion Rule BGV D5 for example stipulates an exchange of these lines after two years at the latest.
