Pneumatic control valve
For reliable operation, the valve seat, seal assembly, brass support ring and valve stem should be replaced at the same time. The SST support ring can be used again.
Cut off the air source.
Remove the air supply hose and electrical wiring on the solenoid valve.
Loosen and remove the high-pressure sealing gland joint and drain joint.
Remove the pneumatic control valve and its actuator components from the ultra-high pressure jet pump.
Figure 9－27： Pneumatic control valve assembly
2 Stemp/ Needle
3 SST backup ring
4 Brass backup ring
HP M／F Adapter
5 HP seal
Loosen and remove the actuator.
Loosen the high-pressure joint, and remove the high-pressure joint, the tapered part of the high-pressure joint and the valve seat.
Remove the stem, SST backup ring and brass backup ring from the valve body.
Remove the sealing assembly by pushing the sealing assembly with a wooden, plastic or brass force transmission rod. The seal pushing tool can also be used to remove the seal assembly. The seal assembly should be pushed out through the actuator port on the top of the valve body.
Clean the valve body, taking care not to cause boring damage or scratches.
Figure 9－28： Actuator Seal Installation
HP M／F Adapter
Seal positioning tool
3 Valve body
Seal installation tool
4 Cone adatper
Seal push tool
If the actuator seal assembly is to be replaced, the brass wedge ring should be removed first. Use FML- 2 food grade grease to lubricate a new seal and "O" ring. Insert the seal and "O" ring into the seal installation tool and into the tapered end of the first seal.
Figure 9－28：Seal assembly
1Seal 3 Brass wedge ring
1. Place the seal positioning tool on the opposite end of the valve body, and use a high-pressure adapter to fix the
positioning tool. After the seal is positioned, the seal installation tool is placed in the matching cavity of the valve
2. Fix the positioning tool and use the seal pushing tool to push the boring of the valve body until the shoulder of the
pushing tool touches the seal installation tool.
3. Remove the pushing tool, installation tool and positioning tool.
3. Place the brass wedge ring in the seal pushing tool (thick end first), and use the tool as a positioning datum to
position the wedge ring in the seal. Remove the pushing tool and use your fingertips to gently move the wedge
ring onto the seal.
4. Install the existing SST backup ring and a new brass backup ring to a new valve stem. The "V" groove on the SST
backup ring should face the brass backup ring. The smaller outer diameter of the brass backup ring should face the
seal assembly. Refer to Figure 9－27 for pneumatic control valve assembly.
6. Insert the sealing assembly into the valve body so that the valve stem enters the inner diameter of the sealing assembly.
7. Apply the anti-seize compound to the threads of the actuator, and carefully screw the actuator onto the valve body,
and guide the valve stem into the bore of the actuator. Rotate the actuator clockwise until you feel resistance. Rotate
the actuator 1/4 turn in the opposite direction and quickly turn it clockwise to seat it. It is only allowed to tighten by
hand, and the tightening torque is 5 ft-lbs (7 Nm).
8. Apply the anti-seize compound to all surfaces (except the inner diameter of the new seat). Install the valve seat on
the valve body and insert the smaller outer diameter first.
9. Apply the anti-seize compound to the thread of the high-pressure connector and apply it to the back of the
high-pressure connector. Position the taper of the high-pressure connector on the high-pressure connector and install
the high-pressure connector with a torque of 50 ft-lbs (68 Nm).
10. Replace the 1/4 inch discharge compression nut and collar to a torque of 25 ft-lbs (34 Nm).
11. Apply anti-seize compound to the threads of the 3/8-inch high-pressure gland fitting. Install the collar and gland
fittings to a torque of 50 ft-lbs (68 Nm).
Install the air supply hose and electrical connector to the solenoid valve. Open the air pressure to the actuator,
and check whether the solenoid valve has a leakage point and whether the solenoid valve operates normally.