172-65634MAJ-03 (A-DR20) 6 Oct 2021
9
6. Piping Size/Diffuser
If the secondary air flow
velocity is expected to be
more than 30m/s (100
ft/s), install a diffuser in
order to keep the flow
velocity below 30m/s
(100 ft/s). If the distance
between the A-DR20 and
the air-using equipment
is great, a possible drop
in pressure should be
taken into consideration
when selecting the piping
size.
In addition, when
installing the strainer, the
strainer screen should
be either at the 3 o
’clock
or 9 o
’clock position to
prevent condensate
accumulation..
7. Two-stage Pressure Reduction
Install a pressure reducing
valve at the inlet side of the
A-DR20 wherever the
pressure cannot be reduced
to the desired level with a
single A-DR20 due to
operating range limitations,
such as when the reduction
ratio is greater than 30:1.
8. Accessories
Always install a shut-off valve, pressure gauge and bypass lines at both inlet and outlet.
Ball valves, which will not retain condensate, are recommended for inlet and outlet shut-
off valves. The bypass pipe should be at least ½ of the size of the inlet (primary) pipe.
A-DR20
Open
Closed
Closed
Primary
Side
Secondary
Side
Diffuser
Straight piping: 10d or longer upstream,
15d or longer downstream
(d: nominal diameter)
A-DR20
Primary
Side
Secondary
Side
A-DR20
Primary
Side
Secondary
Side
Pressure
Gauge
Bypass Valve
Inlet
Valve
Outlet
Valve
Safety Valve
(Relief Valve)
Pressure
Reducing
Valve
Bypass Valve
Inlet
Valve
Outlet
Valve
Pressure
Gauge
Primary
Side
Secondary
Side
A-DR20
Pressure
Gauge
Inlet
Valve
Outlet
Valve
Safety Valve
(Relief Valve)
Bypass Valve
Pressure
Gauge
A-DR20
Primary
Side
Primary
Side
A-DR20
Secondary
Side
Secondary
Side
