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3.2 Pressure Relief Valve Assembly
The pressure relief valve assembly is a critical component to any chlorine vaporizer system and
is required by ASME code for operation. This mechanical safety device limits the pressure of
the chlorine pressure chamber to a maximum value. The rupture disc must be installed prior to
installation. Installation to the gas pipeline is made through the use of 1" Ammonia type unions. The
pressure relief valve assembly should also be installed as close as possible to the vaporizer gas outlet
of the pressure chamber. No other interferences can be installed in between the outlet of the vaporizer
and the rupture disc of this assembly. This assembly must be installed horizontally and in the upright
position. Piping coming out of the relief valve must be 1.5" schedule 80 seamless carbon steel and
slope downward outside or to another safe location with an insect screen on the outside end.
The pressure relief valve assembly also includes a pressure switch that may be wired into the signal
output connections box of the vaporizer for Modbus indication of rupture disc failure. It will be wired
into the V- and DI4 input terminals.
3.3 Expansion Chamber Assembly
The expansion chamber assembly is a mechanical safety device used on liquid chemical lines to
prevent pipe rupture in the event of an over pressure condition. Thus, an expansion chamber assembly
must be installed everywhere that the liquid has the potential to become trapped in the pipe. This
includes sections of pipe that could become isolated through ball valves. In any section of pipe that
an expansion chamber is installed on, it must be located at the highest point of this pipe section. The
volume of the expansion chamber must also be sized so that its volume is not less than 20% of the pipe
volume it is protecting. Supports should also be provided to the expansion chamber assembly.
The expansion chamber assembly also comes with a pressure switch that may be wired into the signal
output connections box of the vaporizer for Modbus indication of rupture disc failure. It will be wired
into the V- and DI3 input terminals.
