Document: Maintenance instruction
Product: SLV, SLF, SLH, SLX
Issue: 2
Issue date: 2012-11-05
5
12. Place the box bottom scraper (9a) in the bottom of the gland box. Install the first braid (9) on one of
the long sides of the gate (6). Use a blunt tool in plastic or wood and a hammer to push the braid into
the box. Make sure that the braid ends meets properly. It is important to push the first braid evenly into
the bottom of the box. The joint of the second and third braid must be placed on the opposite long side
of the joint of the previous braid, not on top of each other.
13. Install the gland (8) on the stud bolts (8a).
14. Add washers (8b) and nuts (8c).
15. Install the seats (13), see section A.
16. Put pressure on the gland (8) by tightening the nuts (8c) gradually and crosswise, see figure 4. The
box packing must be
equally compressed all around. Recommended torque for gland nuts, see section D.
17. The gland (8) must put a uniform pressure on the box packing (9). The gland (8) must also be in line
with the gate (6) with the same distance between the gland and the gate all around. Check that there
is no metal contact between the gland (8) and the gate (6).
18. Remove the round bar from the purge ports and install the plugs (55).
19. Install the other components in reversed order according to step 2.
20. Make a function test before the valve is put into operation.
21. Make sure that the valve is fully open.
22. Install the valve in the system according to instructions in the operating instruction.
23. Operate the valve a few times before the system is pressurised.
Note:
The box packing may start to leak when the system is pressurised and the temperature increases. This is
caused due to that the box packing, which is a soft material, moves depending on pressure and tempera-
ture when the valve is operated. If the box packing is leaking, tighten the gland nuts (8c) gradually and
crosswise according to chapter D.
C –Change of box packing when the valve is installed in a system
No work is allowed on the Stafsjö knife gate valve when the system is pressurised or the automatic
actuator is connected. The system must be empty and free from pressure before any work begins
and the actuator and accessories must be disconnected.
Work on the knife gate valve when the system is under pressure can cause damages on persons
and equipment.
Check that the system is free from pressure by:
oObserving the pressure measurement on the system
oOpening the drain on the pipe
When the system is free from pressure and empty:
1. Check the gate (6) visually for damages such as dents and scratches. If the gate is damaged it can
wear out the box packing (9) and the seats (13), which could cause leakage. Stafsjö recommends
changing gate if it is damaged in order to ensure proper operation. Procedure of changing the gate is
described in section B.
2. Close the valve completely.
3. Demount the actuator and top.
g. Demount the hand wheel (1).
h. Loosen the nuts (5b).
i. Lift off the bearing (2c), bearing washer (2b), yoke (2), bearing washer (2b) and
