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3
■EPDT-179c■
4.
4.
4.
4. Theory of operation
Theory of operation
Theory of operation
Theory of operation
The adjusting screw
○
34
compresses
the adjusting spring
○
29
to press down
the diaphragm
○
22
that will open the
directly connected disc
⑩
.
The fluid from the inlet flows through
above the disc
⑩
to outlet side and
also to the external sensing pipe. The
pipe
directly
applies
the
fluid
pressure to the diaphragm
○
22
as
reduced pressure.
While the stop valve at the outlet is
closed,
the
pressure
on
the
diaphragm
○
22
increases until it
overcomes the load from the spring
○
29
,
allowing the disc
⑩
to close.
Fluid at inlet side
Fluid at outlet side
Gradually opening the outlet stop
valve proportionally decreases the
pressure applied on the diaphragm
○
22
until the load from the spring
○
29
enables the disc
⑩
to open.
Portion of fluid flowing toward outlet
applies pressure to the diaphragm
○
22
to balance between the load from the
spring
○
29
,
adjusting the valve
openings to keep outlet pressure
constant.