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EPDT-023c
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ΔP : Differential press. (MPa)
4. Nominal Size Selection Method
When selecting pipe size, please take piping condition and application into consideration and
secure a safety rate of 20% or more for the performance value.
4.1 Nominal Size Selection Chart
<For Liquid>
Fig. 5
Example of Selection
For example, take a pressure regulating valve whose pressure differential before/after a valve(ΔP)
is 0.2MPa, specific gravity is 1(water), flow rate(V) is 5.5m3/h. Firstly, vertically proceed on the line
of pressure differential 0.2MPa to come across the flow rate 5.5m3/h , and regard this point as(A).
Point(A) is between nominal size 25A and 32A. Select the lager nominal size 32A.
For example, take a pressure regulating valve whose condition is same as above, but specific
gravity is 0.7. Firstly, vertically proceed on the line of pressure differential 0.2MPa to come across
the line of specific gravity 1, and regard this point as (B). Move, in parallel to diagonal line, to
intersection point (C) with the line of specific gravity 0.7. Vertically proceed from point (D) to come
across the flow rate 5.5m3/h , and regard this point (E). Point (E) is between nominal size 20Aand
25A. Select the lager nominal size 25A.
(C)
・
・
(B)
(A)
(D)
V
:
Fl
ow
r
at
e
(m
3
/h)
V
:
Fl
ow
r
at
e
(m
3
/h)
