9
4.9 Re-assembly of the valve
•
Place the valve body (1) and the body cap (2) on the pipe flange
end. Use a level surface that will not scratch the flanges.
Pre assembly of the seats
S and T seats:
Check the sealing surfaces.
•
Place the back seal (O-ring) (63) into the groove in the seat. See
Figures 13 and 14.
•
Place the back-up rings (64) made of PTFE strips at the side of
the O-ring. To ensure that the seam becomes flexible, the strip
must have slanted ends.
•
For easier assembly, lubricate the O-ring and backup ring sur-
faces facing the seats with silicone grease or another suitable
substance. Please ensure the compatibility with the flow medium.
•
Place the spring (62) into the groove in the seat (7). Connect the
ends of the spring.
•
Place the seats into the body and body cap by hand or if neces-
sary, using a plastic mallet. The seat is in correct position when
the spring touches the body shoulder.
D and B seats:
K and G seats:
H seats:
•
Check the sealing surfaces.
•
Place the back seal (63) into the seat (7). See Figure 18.
•
Place the seat into the body counterbore.
L seats:
L seats:
•
Measure the 0-torque of the valve. It should be acc. to Table 2.
0-torque shall be adjusted with graphite plate rings (available
thicknesses are 0.2, 0.5 and 1.0 mm).
Table 2
0-torques
Roughness of the surfaces in contact with graphite back seals shall
be Ra 0.4 or better. Sharp edges shall be rounded off. Apply a thin
and even layer of molybdenum grease spray on cleaned ball and
seat surfaces before assembly.
•
Place the O-ring (63) and the back up rings (64) into the grooves
of the ball seat (7) and lubricate them with silicone grease.
Fig. 13
S seat
Fig. 14
T seat
Fig. 15
D seat
Fig. 16
B seat
62
7
63
64
62
7
63
64
63
7
129
130
62
63
7
129
130
62
75
Fig. 17
G and K seat
Fig. 18
H seat
Fig. 19
L seat
DN / NPS
0-torque (Nm / lbf ft)
1-seat
2-seat
80 / 3
50-100 / 37-74
150-200 / 110-148
100 / 4
100-150 / 74-110
200-250 / 148-184
150 / 6
150-200 / 110-148
250-300 / 184-221
200 / 8
200-250 / 148-184
300-350 / 221-258
250 / 10
250-300 / 184-221
350-400 / 258-295
300 / 12
300-350 / 221-258
400-450 / 295-332
350 / 14
350-400 / 258-295
450-550 / 332-405
400 / 16
400-500 / 295-368
550-650 / 405-479
63
7
129
130
62
75
63
7
7
63
64
129
196
