Page 1
space is limited
ease of installation
without closing spring
API 598
travel
water hammer in liquid media
according to Pressure Equipment Directive
/minute - regardless of connection size - for specifi ed test
PN
Page 2
40 -250
40 -250
Page 3
Page 4
on the horizontal
on the horizon-
tal axis is larger than 200 (point 2-E) in a vertical pipe, or
the pressure drop across fully open valve on the vertical
/h the pressure drop
- fi g. 2.
Page 5
v m/s
= 1000
= 1,3 kg/m
= 1,3 x 15
= 1,3 x 225 = 292
open. Pressure drop 0,052 m wC
Flow velocity 2 m/s
x v
= 1000 x 2
= 4000
Pressure drop 0,73 m vp
spring
Fully open
valve
The valve is not fully open -
Page 6
0,1 1 3 5 7 10 3 5 7 100 3 5 7 1000
/h water
spring-assistance and as fi tted
in a horozontal pipe.
assisted disc and as fi tted in
a horizontal pipe.
Before the valve is fully open,
the pressure drop across it
exceeds the value shown - see fi g. 1.
Valve fully open - without spring-
assistance and as fi tted in a vertical
pipe.
assisted disc and as fi tted in a
vertical pipe.
Location on suction side of centrifugal
pumps. Place the check-valve on the delivery
side to avoid starting and cavitaton problems.
4.
Pumps in parallel. Make certain that pump
characteristic fall the entire fl ow range.
Small, pulsating gas fl ows
from a piston compressor
The valve selected in such cases shall be small
enough to open fully during normal operations,
thus preventing fl utter.
Low-pressure gases.
force is affected by density. Make certain that
velocity and density are adequate to open the
valve - fi g. 1.
�
.
(�
in kg/m
and Q in m
/h)
Page 7
528530
Auxiliary
The NAF-Check valve can be installed in vertical
valve.
Oblique seat results in short closing swing
(DN 40 and DN 50 have straight seats)
Page 8
indicates that the internal diameter of the pipe flange
as shown in the table on page 7.
ANSI
Weld neck
xxxxxxx
x
xxxxxxx
x
xxxxxxx
x
ANSI
Weld neck
ANSI
to B16.1
Weld neck
xxxxTx
xxxxTxx x
x
xxxxTxx x
x
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