wT 2860/02
Page 18
The preferred welding methods for the creation of welding seams are:
-
Manual electro-welding
-
TIG
-
MAG / MIG
The welding seam sequence is defined
as follows:
Vertical-down weld: A - C - D - B
Rising weld: A - C - B - D
12
Service and Maintenance
Maintenance and inspection intervals are to be determined by the operator dependent
on the operating mode, as these valves can be utilized under a number of different
operating conditions.
In order to increase service life at low activation counts, we recommend carrying out an
activation from time to time. For this purpose it is fully sufficient to only shift the ball by a
few angular degrees.
Maintenance and inspection work may only be carried out by trained personnel.
Prior to the start of service and maintenance work, it must be ensured that the pipeline
system is depressurized and that no medium residues are contained within.
In the event of tightness to atmosphere not being achieved at certain positions, the
tightening torques at the corresponding positions should be checked for their conformity
with the tightening torque table.
When removing an actuator, it is necessary to protect it against rotation prior to loosening
of the connecting screws.
12.1
Disassembly
12.1.1
Disassembly for Seal Exchange at the Operating Stem
»
Depressurize the pipe system
»
Bring the valve into the OPEN position
»
Remove valve lever and actuating unit respectively
»
Loosen top flange head screws (Pos. 31) and lift top flange (Pos. 7) over the end
of the operating stem
»
Remove washer (Pos. 16) – please note that these must be reinstalled in the
correct amount and strength during assembly
»
Pull the bush insert – upper part (Pos. 8) out of the body – use the extraction
groove
0
D
B
A
C
3
9
6
