Installation and Commissioning
Valve with Welding Ends
28
Operating Instructions · VARIVENT
®
Mixproof Valve L with Lifting Actuator, suitable for pigging operation
Edition 26/08/2016
Valve with Welding Ends
This section describes the welding procedure for the valve.
WARNING
Spring tension in the valve
Danger of injury when opening the clamp joint at the actuator or at the housing as the
released spring pretension will suddenly lift the actuator.
Therefore, release the spring tension before detaching the clamp joint by pressur-
izing the actuator with compressed air at max. 10 bar.
IMPORTANT NOTE
Seals are wearing parts
Old seals will cause malfunction of the valve
When fitting the valve be sure to fit new housing O-rings.
Carry out the following steps:
1.
Release the spring tension.
2.
Remove the valve insert, see chapter “Disassembling the Valve“ (Page 37).
3.
Fit the housing without sealing rings.
4.
Fit the housing into place and tack it.
5.
Always close the housing before welding.
6.
Flush the housing with forming gas from the inside to push the oxygen out of the
system.
7.
Weld the housing into the pipe system; use welding filler if necessary. Use the TIG
welding with pulse method.
8.
Passivate the seam after welding.
9.
Fit the seals.
10.
Assemble the valve and depressurize the actuator.
The valve disk is lowered.
Done
