Document: Maintenance instruction
Product: HL/HG/HP/HPT/HX
Issue: 4
Issue date: 2017-02-27
6
B –Change of box packing
Place the valve upright in for example a screw vice to simplify changing the gate and box
packing. Large valves shall be placed on a horizontal work bench.
1. Close the valve.
2. Demount the actuator and top by:
Pneumatic cylinder (18)
1. Disconnect the air connections so that the cylinder (18) is depressurised.
2. Remove the gate guards (16).
3. Demount the split pins (21) and clevis pin (20).
4. Loosen the nuts (5b) keeping the cylinder in place.
5. Lift off the cylinder (18).
6. Demount the beam (7) and tie rods (5) from the valve
Hand wheel (1)
1. Demount the hand wheel (1).
2. Loosen the nuts (5b).
3. Lift off the bearing (2c), bearing washer (2b), yoke (2), bearing washer (2b)
and bearing (2a) from the stem (3).
4. Demount the beams (7) and tie rods (5).
5. Loosen the screw (4b) from the stem nut (4) and gate (6).
6. Lift off the stem (3) and stem nut (4).
3. Loosen the nuts (8c) on the gland (8).
4. Lift of the gland (8) from the stud bolts (8a).
5. Remove the box packing braid (9) and if any, box support (9a/b).
6. Clean the box from residues.
7. Check the gate (6) visually for damages such as dents and scrapes. Do not remove
the gate (6) from the valve body (10). If the gate is damaged it can wear out the box
packing (9) and the seat (13), causing leakage. Stafsjö recommends changing the
gate if it is damaged to ensure the function of the valve.
8. Check that the guide strips (14a/b) in the valve body are not worn out and in place.
9. If any, check the box support (9a/b) for damages. If the box support (9a/b) is damaged
Stafsjö recommends changing it. Place the box support (9b), in the valve body (10).
10. Begin assembling 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. Where the
braid ends meet, check that the short ends are opposite each other, not on top of each
other. It is important to push the first braid evenly into the bottom of the box. The joint
of next braid must be placed on the opposite long side of the joint of the previous braid.
If any, place box support (9a) on top of the braids.
11. Place the gland (8) on the stud bolts (8a).
12. Add the washers (8b) and nuts (8c).
13. Put force on the gland (8) by tightening the nuts (8c) gradually and crosswise. The
box packing must be equally compressed all around. Recommended torque for gland
nuts, see chapter D.
14. The gland (8) must put uniform force on the box packing (9) and be in level with the
top of the valve body (10).
