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4.5 Welding procedures
NOTE:
Electric welding must be used to
weld the valve in place.
· Recommended welding method is manual
metal arc welding. Recommended welding
rod is ESAB OK 48.00 or equal (standard: EN
ISO 2560-A; classification: E 42 4 B 42 H5).
· Valve may be welded only by an authorized
mechanic, following valid norms and
standards.
· The valve must remain closed during
installation and welding to ensure that welding
residue does not damage the seal surfaces.
· The ends of the pipes must be parallel to the
valve and correctly aligned.
· The length of the valve must be the same as
the distance between the pipe ends, taking
into consideration the welding gaps.
· Diameter and wall thickness of the pipes must
be compatible with the welding ends of the
valve
· It is recommended to install the valve so
that the main flow direction is same as the
recommended flow direction for the valve.
· The recommended installation position for the
valve is at an angle (see Figure 19.) or with the
shafts in the horizontal position
(see Figure 18.). Avoid installation with the
shafts fully upright.
4
2
Figure 18. Welding the seams.
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1
3
NOTE:
The greatest angle between stem
axis and horizontal axis is 45
degrees (see Figure 19.).
· The valve must first be bridged to the
pipeline using spot welding, with 4–8 seams
alternately on opposite sides of the valve.
· Then the seams between the bridges are
welded as shown in Figures 18. and 19.
Welding order: 1-2-3-4.
· Any lid welding must be carried out at a
minimum of 200 mm from the valve seam.
· During welding the ground must be
connected to the pipe of the valve body or the
pipeline. Ground cable should be connected
to the pipe on the same side as the welding
seam. Otherwise the current may damage the
valve seal. Never connect the ground to the
valve neck, actuator flange or actuator.
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4
2
Figure 19. Welding the seams.
3
max 45º
15
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