Removing The Valve From The Pipeline; Replacing The Gland Packing - Metso Neles L4 Series Intallation, Maintenance And Operating Instructions

8
NOTE:
For safety reasons, replace pressure retaining bolting if the
threads are damaged, have been heated, stretched or cor-
roded.
5.2

Removing the valve from the pipeline

CAUTION:
Do not dismantle the valve or remove it from the pipe-
line while the valve is pressurized!
It is generally most convenient to detach the actuator and
its auxiliary devices (see Section 6), before removing the
valve from the pipeline. If the valve package is small or diffi-
cult to access, it may be more practical to remove the entire
package at the same time.
Ensure that the valve is not pressurized and the pipeline is
empty. Ensure that the medium cannot flow into the sec-
tion where servicing is to take place. The valve must be in a
closed position when removing.
Support the valve carefully with a hoist. Place ropes care-
fully and unscrew the pipe flange bolts. Ensure that the
ropes are positioned correctly. Lift valve correctly (see
Fig. 3).
5.3

Replacing the gland packing

CAUTION:
Do not dismantle the valve or remove it from the pipe-
line while the valve is pressurized!
PTFE V-rings are used as a standard gland packing and
graphite rings for high temperature constructions. The
packing construction is live loaded as standard.
The gland packing (20) must be changed if leakage occurs
even after the hex nuts (25) have been tightened as recom-
mended.
5.3.1 L6C, L6D, L6F/D and L4F/D

Make sure the valve is not pressurized.

Unfasten the nuts (25) and remove the disc spring
(TA-Luft) kits (43), the retaining plates (42) and the
gland (9).

Remove old packing rings (20). Do not damage the
surfaces of the packing ring counterbore and shaft. It
is not necessary to change anti-extrusion ring (22).

Clean the gland and packing ring counterbore.
Install new set of packings (V-ring or graphite). Slip
the rings onto the shaft. Ensure that there are no
burrs in the keyway groove which could damage the
packing.

Install the gland.

Mount the retaining plates with the text UPSIDE on
top (see Fig. 10).

Mount the disc spring kits.

Place the nuts on the studs.

Pre-compress the gland packing by tightening the
nuts with a tool until the disc springs have value of
compression (h –h
1

Carry out 3...5 operation cycles with the valve. Suita-
ble range of movement is about 80 %.
It is not necessary to fully close or open the valve
during the operation.

Unfasten the nuts and disc springs.
) as in Tables 7 and 8.
2
Fig. 10. Mounting the retaining plates

Measure the height h
these values as a basis when defining the final
height of the springs (as compressed condition).

Re-install the disc springs and tighten the nuts with
the tool. Tighten the nuts until the set value of com-
pression (h –h ) of disc springs is achieved, see
1 2
Tables 7 and 8.
Table 7. Tightening of gland packing, L6C and L6D
Spring set
L6C L6D
dia
DN / NPS DN / NPS mm
100 / 4 100 / 4 20
150 / 6, 200 /
150 / 6 20
8
250 / 10 200 / 8 25
300 / 12 25
350 / 14 250 / 10 25
400 / 16 25
450 / 18 300 / 12 35.5
500 / 20 350 / 14 35.5
600 / 24 400 / 16 35.5
700 / 28, 450 / 18,
40
750 / 30 500 / 20
800 / 32 600 / 24 40
900 / 36, 700 / 28,
50
950 / 38 750 / 30
1000 / 40 50
1200 / 48 50
800 / 32 56
900 / 36 50
1400 / 56 71
1000 / 40,
56
1200 / 48
1400 / 56 80
Table 8. Tightening of gland packing, L6F/D and L4F/D
L6F/D
Spring set dia
L4F/D
DN / NPS mm
100 / 4 25
150 / 6 25
200 / 8 35.5
250 / 10 40
300 / 12 50
350 / 14 50
400 / 16 50
450 / 18 50
500 / 20 56
600 / 24 56
700 / 28 71
750 / 30 71
900 / 36 56
2 L6 70 en
of the disc springs and use
1
Compression (h –h
1
Thread
Packing ring material
Graphite +
M, UNC
PTFE
M8, 5/16 2.0
M8, 5/16 2.5
M10, 3/8 2.5
M10, 3/8 3.0
M10, 3/8 3.0
M10, 3/8 3.0
M14, 1/2 4.5
M14, 1/2 4.5
M14, 1/2 4.5
M18, 5/8 5.0
M18, 5/8 5.5
M20, 3/4 6.0
M20, 3/4 6.5
M20, 3/4 6.0
M24, 1 6.5
M22, 7/8 6.5
M30, 1 1/4 6.5
M24, 1
6.5
(4 pcs.)
M36, 1 1/2 9.0
Compression (h –h
1
Thread
Packing ring material
M, UNC Graphite + PTFE
M10, 3/8 1.5
M10, 3/8 1.5
M14, 1/2 2.0
M18, 5/8 3.5
M20, 3/4 4.0
M20, 3/4 3.5
M20, 3/4 3.5
M22, 7/8 4.0
M24, 1 6.0
M24, 1 6.5
M30, 1 1/4 6.5
M30, 1 1/4 6.5
M24, 1
6.5
(4 pcs.)
), mm
2
PTFE
1.0
1.5
1.5
1.5
2.0
2.0
2.5
2.5
3.0
3.0
3.5
4.0
4.0
5.0
5.5
5.0
6.5
6.0
6.5
) mm
2
PTFE
1.0
1.0
1.0
1.5
2.0
2.0
2.0
2.5
3.5
4.0
4.0
4.0
5.0