Burkert Type 2731 - Manual (Page 28)

Actuator
Valve body
Lower pilot air port
Upper pilot air port
Body screws (4x)
Diaphragm
Marker flap of the
diaphragm
Fig. 20: Repairs
replacement for control functions B
→
Clamp the valve body in a holding device.
(applies only to valves not yet installed).
→
Loosen the four body screws.
→
Remove the actuator from the body.
→
Unbutton or unscrew old diaphragm. If attachment is with a
bayonet catch, remove the diaphragm by rotating it through 90°.
→
Install new diaphragm.
→
Align diaphragm.
the marker flap of the diaphragm must be perpendicular to
the direction of flow (see “Fig. 20”)!
→
Place actuator back on the body.
→
Lightly cross-tighten the body screws without pressurization until
the diaphragm is between the body and actuator.
do not tighten screws yet.
→
Pressurize upper pilot air port of the actuator with compressed
air (5 bar) (see “Fig. 20”).
→
Actuate the diaphragm control valve twice.
→
With pressurization tighten the body screws to the per-
mitted tightening torque (see “Tab. 14: Tightening torques for
diaphragms”).
Orifice dn
(diaphragm
size)
tightening torques for diaphragms [nm]
epdm ptfe
15 3.5 4
20 4 4.5
25 5 6
32 6 8
40 8 10
50 12 15
Tab. 14: Tightening torques for diaphragms
28
Repairs
english
Type 2730 / 2731 / 2731K