16
17
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Ls ≥ L
Ls ≥ L
L mm
Figure 20. Cover the seal and disc with a water
cushion of minimum 40 mm.
If the valve is welded to a vertical pipeline,
close the valve and cover the seal and disc
with a water cushion of at least 40 mm
(see Figure 20.).
The water protects from welding spatters that
may damage the seal and disc surfaces during
welding.
· The recommended method of welding
the valve to the pipeline is welding with
connection pipes (see Figure 21.). Tack
welding and the welding order for the seams
are the same as in Figures 18. and 19.
Welding order: 1-2-3-4.
· The valve must remain closed during
installation and welding to ensure that welding
residue does not damage the seal surfaces.
· This also facilitates cleaning of the inner
surfaces from welding residue and impurities.
Figure 21. The recommended method.
4.5.2 Welding with connection pipes (recommended method)
4.5.1 Installation in a vertical pipeline