172-65188M-08 (
M-COS 3,16,21
Pressure Reducing Valve) 24 Jun 2015
8
4. Precautions for the Installation of Additional Fittings Before or After the
M-COS
In order to ensure stable steam flow, the piping upstream and downstream of
the
M-COS
must be straight runs. If a
M-COS
is installed either directly before or
after an elbow or control valve, unevenness in steam flow may result in
chattering and unstable pressure.
To ensure stable steam flow, it is recommended that the
M-COS
be installed on
straight runs of piping, as illustrated below.
(d = pipe diameter)
(1) Inlet (primary side) of the
M-COS
Maintain a straight piping
run of
10 d or more
when a
manual valve, a strainer or
an elbow, etc. is installed.
(Example: if nominal size is 25
mm, have 250 mm or more)
M-COS
10 d or more
Less
than
10d
M-COS
Maintain a straight piping
run of
30 d or more
when
an automated valve (on-off
valve) is installed.
(Example: if nominal size is 25
mm, have 750 mm or more)
30 d or more
M-COS
Automatic
Valve
Automatic
Valve
Less than
30 d
M-COS
(2) Outlet (secondary side) of the
M-COS
Maintain a straight piping
run of
15 d or more
when a
manual valve, a strainer or
an elbow, etc. is installed.
(Example: if nominal size is 25
mm, have 375 mm or more)
M-COS
15 d or more
Less
than
15 d
M-COS
Maintain a straight piping
run of
30 d or more
when a
safety valve is installed.
(Example: if nominal size is 25
mm, have 750 mm or more)
M-COS
30 d or more
Safety Valve
Less than
30 d
Safety Valve
M-COS
Maintain a straight piping
run of
30 d or more
when
another pressure reducing
valve is installed. (Two-
stage pressure reduction)
(Example: if nominal size is 25
mm, have 750 mm or more)
30 d or more
M-COS
M-COS
Less than
30 d
M-COS
M-COS
Maintain a straight piping
run of
30 d or more
when a
control valve or an
automated valve (on-off
valve) is installed.
(Example: if nominal size is 25
mm, have 750 mm or more)
Control Valve
or
Automatic Valve
M-COS
30 d or more
Less than
30 d
M-COS
Control Valve
or
Automatic Valve