Burkert Type 2731 - Manual (Page 27)

11.2 replacing the diaphragm
required spare part
• Diaphragm
fastening types
Orifice dn
(diaphragm
size)
fastening types for diaphragms
ptfe epdm / fkm
15 Diaphragm buttoned
Diaphragm buttoned 20
Diaphragm with bayonet
catch
25
32
Diaphragm with bayonet
catch
Diaphragm screwed in 40
50
Tab. 13: Fastening types for diaphragms
Danger!
risk of injury from discharge of medium and pressure!
It is dangerous to remove a device which is under pressure due to
the sudden release of pressure or discharge of medium.
▶ Before removing a device, switch off the pressure and vent the
lines.
replacement for control function a
→
Clamp the valve body in a holding device
(applies only to valves not yet installed).
noTiCe!
damage to the diaphragm or the seat contour!
▶ When removing the actuator, ensure that the valve is in open
position.
→
Pressurize lower pilot air port of the actuator with compressed
air (5 bar): valve opens.
→
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.
→
Insert the body screws and lightly cross-tighten until the dia-
phragm is between the body and actuator.
do not tighten the screws yet.
→
Actuate the diaphragm control valve twice.
→
Without pressurization tighten the body screws to the per-
mitted tightening torque (see “Tab. 14: Tightening torques for
diaphragms”).
27
Repairs
english
Type 2730 / 2731 / 2731K