Metso L12 Series, Installation Maintenance And Operating Instructions

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10 2 L12 71 en

Drill the holes deep enough, but not to reach the
disc.

Pull the pins out.

Dismantle the gland packing according to
Section 5.3.

Detach the screws (26) and the blind flange (10) and
remove the gasket (18).

Place rubber strips or other protection between the
disc edge and the body and remove the shafts,
Fig. 15.

Remove the bearings (15, 16).

Clean and check all parts carefully.
5.6 Assembling the valve

Replace damaged parts with new ones.

Set the disc and the shaft together beforehand. In
case the pin holes have been damaged during
removal of the old pins the holes can be drilled to a
larger pin size. File off any burrs from the shafts.
The bearing material of the standard construction valves is
PTFE-impregnated stainless steel net.
The bearings for the high temperature valves (H-construc-
tion) are cobalt alloy bushings which are mounted into the
body together with the shafts.

Mount the bearings into the body (see Fig. 16).

Place the disc horizontally on a surface so that the
flat side of the disc lays against the surface. Lift the
body around the disc so that the shaft bores are
aligned with the bores in the disc. Protect the disc
(see Fig. 15).

Press the shafts into the disc drillings. Align the pin
holes. The shaft (13) position against the disc must
be according to Fig. 13.

Support the disc well in a horizontal position during
mounting of the pins. Push the new pins into the
holes and press them in a press to final form (see Fig.
17). Use a smaller tool than the pin diameter. See
Table 6 for force needed.

Install the gasket (18) and the blind flange (10).
Screws of the blind flange must be tightened evenly,
see Table 7. An unevenly tightened flange will dam-
age the seat.

Install the seat ring. See details in Section 5.4.

Install the body seal (19) and the clamp ring (2). See
details in Section 5.4.

Install the gland packing (see Section 5.3).

Check the contact line between the seat ring and the
disc (see Fig. 13).
Fig. 15 Protecting the disc during disassembly and assembly
Fig. 16 Mounting the standard bearings
NOTE:
Use only pins supplied by the manufacturer!
NOTE:
The pins must be pressed with enough force to deform
them so that the connection will be free from backlash.
Fig. 17 Pressing the pins
Table 6 Pressing the pins, forces
Pin diam., mm Force kN Pin diam., mm Force kN
5 45 20 500
6 60 25 780
8 80 30 1125
10 125 35 1500
12 180 40 2000
15 280 50 3150
Table 7 Torque values for blind flange screws,
sizes 80–1400
Screw M6 M8 M10 M16 M20
Torque
[Nm] 8 18 35 170 330