详情
Floating Ball Valve
Nominal Size: 1/2”~8”
Pressure rating: Class**0LB~**0LB
Design standard: API 6D, BS***1, API **8, ASME B*6.*4
End to end: DIN***2, API 6D, ASME B*6.*0
Connection Type: Flanged ends, Butt-welding ends
Materials: WCB, LCB. CF8, CF8M, CF3, CF3M, A**5, LF2, F**4, F**6,
F**4L, F**6L, F*1
Operation Style: Lever, Worm gear, Pneumatic, Electric Actuator,
Hydrodynamic
Test standard: API **8, API 6D, BS ***5, DIN***0
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
**-
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 |