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Document id
Issue Date
Maintenance instruction
mi-WB14E-HW-SC-EN 1
2021-04-14
6 (10)
If the gland nuts are tightened to hard, it shortens the lifetime of the box packing and the force
needed to operate the valve will increase.
The box packing may start to leak when the system is pressurized and the temperature
increases. This is caused by the box packing which is a soft material that moves depending on
pressure and temperature and when the valve is operated. If the box packing leaks, re-tighten
the gland nuts (8c) gradually and crosswise according torque above.
From DN 350/14”, follow steps below to change box packing, scrapers, seat and guiding pads.
1.
Place both valve body halves on a bench and check that the inside is clean. Put some spacers between
the halves, conveniently a thinner piece under the top and a thicker in the bottom. It should be possible
to get in the screws from below!
2.
Make sure that the valve body gate groove is cleaned and free from grease
and residues.
3.
Apply approx. 3 mm wide Terason adhesive paste in the seat groove in the
gland box and apply it approx. 50 mm below the gland box.
4.
Take the seat (13) with the short pins installed (13b) in each end of the seat
and install it into the seat (13) groove in the valve body. Use clamps to hold
it in place. The seat should extend approximately 2 mm in the bottom of
the gland box (the braid will compress it). Make sure that steel pins are
inserted in the housing.
5.
Install new guiding pads (14) in the guiding pads groove in the valve body.
6.
Apply approx. 3 mm wide Terason adhesive paste in the seat groove in the
gland box and apply it approx. 50 mm below the gland box on the other valve body side.
7.
Put the other valve body half in place on top of the one with the seat installed.
a.
Make sure that the seat profile pins are inserted correctly in each valve body halves.
b.
Insert three body bolts, two in the top and one in the bottom, tighten them gently by hand.
c.
Check that the seal profile is positioned correctly.
d.
Tighten the body bolts again and then insert the rest of the body bolts.
e.
Tighten them but let it be approximately 0,5-1 mm space between the body halves in the lower
area. In the top, tighten the longer bolts according to torque chart below. Tighten remaining
valve body bolting after the actuator have been installed.
8.
Apply grease (Multipurpose Grease OKS 1110 or similar grease approved for EPDM, Nitril and FEPM) on
the gate edges.
9.
Push down the gate (6) to the bottom (100 % closed position) of the valve body (10) by using your own
weight or use a plastic surfaced hammer. If you have not tightened the valve body bolts all-around it
becomes easier. However due to the friction you may need to use a pneumatic cylinder, to get the gate
down into 100 % closed position. Ensure the gate is cantered and the seat is still in correct position in
the gland box.
10.
Install the first layer of TwinPack box packing braid (9). Make sure they close tightly against the seat.
NOTE! Do not use any sharp tools when installing the box packing braids. It can damage the box packing
and the gate!
11.
Add box bottom scraper (9a) on top of the first layer of braids. Box bottom scrapers are a bit thicker
than optional top scrapers. Ensure you install correct ones.
12.
Add another layer of TwinPack braid (9) on top the scrapers. Make sure the braid ends does not meet on
the same side as the first layer.
13.
Add final layer of TwinPack braids. Make sure the braid ends does not meet on the same side as the
second layer.
Screw joints Sd mm
Max recommended torque
Nm for stainless steel A2/A4
Max recommended lbf x ft
stainless steel A2/A4
M12
100/100
74/74
M16
140/190
103/140
M20
275/365
203/269
