Instruction Manual
D104709X012
8540 Valve
September 2021
4
Table 4. Maximum Allowable Pressure Drops at Temperature
TEMPERATURE
PRESSURE DROP
5
C
5
F
bar
psi
-46
-50
52
750
-32
-25
-18
0
38
100
66
150
93
200
43
620
121
250
35
510
149
300
27
390
204
400
11
160
232
450
3
50
Valve Orientation
Valve Direction
The high performance butterfly valve is designed to allow flow in either direction when in the open position. When in
the closed position, high pressure should be applied to a specific side of the disk to provide best performance and
optimal valve life (see seal types below). See figure 2.
The PTFE soft seal is bi‐directional under normal operating conditions can (at different times) experience pressure in
both directions; the highest of the two pressures should be exerted on the preferred side of the disk. If the two
pressures are equal, then the one lasting the longest period of time should be applied to the preferred side.
1.
For PTFE seal ring:
This seal is bidirectional. For optimal performance, high pressure should be applied to the front
(retaining ring side) of the disk.
Figure 2. Flow Direction Arrow
FLOW ARROW
FORWARD FLOW
REVERSE FLOW
RETAINER RING SIDE
FLOW ARROW
RETAINER RING SIDE
