5.7 Piping Supports / Maintenance Space
Leave sufficient
space for
maintenance,
inspection and
repair.
Install the
DR20/A-DR20, paying
attention to avoid
excessive load,
bending and vibration.
Supporting the inlet
and outlet pipes
securely is
recommended.
5.10 Accessories
Always install a shut-off valve and pressure gauge at both the inlet and outlet, and a shut-off
valve in the bypass line. Ball valves, which will not retain condensate, are recommended for inlet
and outlet shut-off valves. The bypass pipe should be at least 1/2 the size of the inlet pipe.
5.8 Piping Size / Diffuser
If the secondary side flow velocity is expected to be more than 30 m/s (100 ft/s), install a
diffuser in order to keep the flow velocity below 30 m/s (100 ft/s). If the distance between the
reducing valve and the equipment is great, a possible drop in pressure should be taken
into consideration when selecting the piping size.
5.9 Two-stage Pressure Reduction
Employ 2-stage pressure reduction if the required reduction is not possible due to operating
range limitations (when it is not possible to reduce the pressure to the desired pressure using a
single pressure-reducing valve).
Straight piping: 10 d or longer upstream 15 d or longer downstream
Pressure
Gauge
Pressure
Gauge
Globe Valve
Diffuser
Safety Valve
(Relief Valve)
Ball Valve
Ball Valve
DR20/
A-DR20
150
mm
(6
″
)
150
mm
(6
″
)
150 mm
(6
″
)
150 mm
(6
″
)
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English
