Description

Forged Steel Gate Valve
Nominal size: 3/8”~2”
Pressure rating: Class**0LB~***0LB
Design standard: API**2, BS***2, ASME B*6.*4
End to end: ASME B*6.*0
Connection type: Thread ends, Socket welded ends
Materials: A**5, LF2, F*1, F*2, F5, F**4, F**6, F**4L, F**6L, F*1
Operation style: Handwheel
Test standard: API**8
 

1. Scope
This manual covers motor or manually operated gate valves of different types having nominal size DN*5mm~**0mm(1/2”~*4”) and class PN1.6MPa~*6MPa(ANSI CLASS**0~**0). The valve ends can be threaded, flanged, butt-welded or socket-welded.
2. Application
2.1 Gate valves are used to open/close the flow in the pipeline.
2.2 The nature of applicable fluid depends on valve material.
2.2.1 Carbon steel valves apply to non-corrosive fluid, such as water, vapor or oil, etc.
2.2.2 Stainless steel valves apply to corrosive fluid.
2.3 Temperature range：
2.3.1 Carbon steel valves  **9℃~***5℃
2.3.2 Alloy steel valves   ≤**0℃
2.3.3 Stainless steel valves ***6℃~***0℃
3. Structure
3.1 Valve structure is shown in Fig.1
3.2 Gasket and packing are PTFE or GRAPHITE. They are used to secure sealing.
4. Operation
         Manual valves or motor valves use hand-wheel or electric actuator to open or close the valve by stem and disc rising or moving down. When the drive set moves clockwise the disc moves down to close the valve. When the drive set moves anticlockwise the disc moves up to open the valve.
5. Storage, maintenance, installation and service
 5.1 The valve should be stored in dry room with good ventilation. Valve ends should be covered.
5.2 For valves stored for a long period of time, regular checkup is required to ensure that the valves are in good conditions. Foreign particles should be removed and special care should be taken to keep the valves seat sealing face.
5.3 Check the conformance of valve identification to the service requirements prior to installation.
5.4 Check the cleanness of the valve cavity and sealing surface and wipe off any dirt with white cloth prior to installation.
5.5 Before installation, the tightness of packing should be checked to ensure that sealing is secured without affecting the movement of stem.
5.6 The valve shall be in full open position when conducting system or pipeline pressure test after the valve installation.
5.7 Gate valve shall be in full open or full close position whole in service. Partial opening for controlling the flow is not allowed.
5.8 Lubricant should be injected regularly to the stem thread while in service.
5.9 Manually operated valve should be operated by using the hand-wheel. Use of levers or other tools is not allowed.
5.*0 Valve in service should be examined at prescribed intervals to see whether the wear of sealing surface or stem occurs and the gasket or packing fails. Repair or replacement shall be carried out timely if necessary.
5.*1 Electric Valve Actuator Instruction Manualshould be referred with regard to the storage, maintenance, installation and service for motor-operated valve.
 
6. Possible troubles, cause and solution    
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  Possible troubles, cause and solution

Possible trouble	Cause	Solution
Leakage through packing	1.Packing not sufficient pressed 2. Packing failure	1.Tighten the nut to press packing evenly 2.Replace packing
Leakage from sealing surface	1. Some contamination adhered to the sealing surface 2. Damage of the sealing surface	1.Clean up the contamination 2.Repair or change
Leakage from middle flange	1.The body and the bonnet are not joint tightly 2.The sealing surface of middle flange spoiled 3.Gasket is broken or useless	1.Fix bolts and nuts averagely 2.Repair the sealing surface 3.Change the middle flange gasket
The hand-wheels cannot turn smoothly or cannot open and close the valve	1.Packing is pressed too tight 2.Packing gland is deflected 3.The stem nut has damaged 4.The screw thread of the stem nut is destroyed or broken 5. Stem is not straight	1.Loosen the nuts properly 2.Adjust packing gland 3.Repair the thread and clean contamination 4.Change stem nut 5.Adjust the stem
Trouble of electric actuator and pneumatic actuator	Refer to Electric Valve Actuator Instruction Manual