Instruction Manual

Instruction Manual
D103356X012
24000C Valve
March 2011
4
Air Piping
1. For an air-to-extend actuator (air-to-close action), connect the actuating air pressure line to the 1/4 NPT opening in
the upper diaphragm case. For an air-to-retract actuator (air-to-open action) connect the actuating air pressure line
to the 1/4 NPT opening in the lower diaphragm case.
2. Use 6.4 mm (1/4 inch) O.D. tubing or equivalent for all air lines. If air line exceeds 8 m (25 ft) in length, 9.5 mm (3/8
inch) tubing is preferred. Air pressure should not exceed 2.5 barg (35 psig).
CAUTION
D When assembling or disassembling the valve, do not turn the valve stem while the plug is touching the valve seat. This
will damage the valve's seating surfaces.
D When adjusting the valve stem do not grip the stem directly with pliers or a wrench. This will damage the surface of the
stem, and cause damage to the packing in the valve. Instead, counter-tighten the two locknuts (key 27) on the stem
(key 5). This will allow you to turn the stem by turning the locknuts (key 27) with a wrench.
D When placing valve in a vise, clamp the flat end faces of the valve. Do not clamp the rounded sides of the valve. This will
distort the shape of the casting, and will ruin the valve.
Disassembly
1. Mount the valve in a vise by clamping flat end faces of the valve (figure 2). Caution must be taken not to damage
the serrated flange faces.
2. Remove the actuator, stem locknuts (key 27), travel indicator (key 58)) and yoke drive nut (key 9).
3. Turn the bonnet (key 8) in a counter-clockwise direction from the valve body (key 1). Remove the O-ring (key 12)
and remove and discard the valve body gasket (key 49). A new gasket should be installed each time the valve is
disassembled.
4. Pull the plug and stem assembly (keys 4 and 5) out through the bottom of the bonnet. Rotate the assembly to
prevent damage to the packing. Wipe the parts with a clean soft cloth and examine for signs of wear.
CAUTION
Handle the parts carefully to avoid damaging the seating and guiding surfaces.
5. To remove the seat ring (key 2), fabricate a special wrench to engage the lugs on the ring. Turn the seat ring (key 2)
counter-clockwise to remove it from the valve body (key 1). Clean thoroughly and examine for signs of wear.
Lapping the Metal Seat
If valve seat leakage becomes excessive, it may be necessary to lap the valve seat.
Lapping is the process of mating the valve plug to the seat ring, with an abrasive to produce a close fit. When valve
seat leakage becomes excessive, lapping becomes necessary. The plug and seat ring seating surfaces should be free of
large scratches or dents and the contact surface of the seats should be as narrow as possible.
1. Use a good quality lapping compound with a mixture that contains 280 to 600 grit. Apply at several spots around
the plug seating surface. Replace the plug (key 4) in the bonnet (key 8).
2. Place the bonnet (key 8) loosely into the valve body (key 1) to serve as a guide during the lapping operation.
3. Lap the valve by applying a slight pressure on the stem and rotate the stem in short oscillating strokes
approximately 8 to 10 times or until you see an even and complete lap line. The plug should be intermittently lifted
and turned 90 degrees while lapping to keep the plug and seat ring concentric.