DN200 PN16 ASTM A351 GR. CF8M FEMALE NPT THREADED WCB FLANGED END
CHECK VALVE
What is a Check Valve?
The valve that used to prevent backflow in a piping system is known
as a check valve. It is also known as a non-return valve or NRV.
The pressure of the fluid passing through a pipeline opens the
valve, while any reversal of flow will close the valve.
It allows full unobstructed flow and automatically shuts as
pressure decreases. The exact operation will vary depending on the
mechanism of the valve.
Specifications:
| Nominal pressue (MPa) | 1.0 | 1.6 |
| Nominal diameter(mm) | 50-600 | 50-600 |
| Test pressure | Shell | 1.5 | 2.4 |
| (MPa) | Seal | 1.1 | 1.76 |
| Applicable temperature | 150 |
| Applicable medium | Fresh water, Sewage, Sea water, Air, Vapor, Food, Medicine, Oils,
Acids,
Alkalis, etc. |
| Operating mode | manual, worm gear, pneumatic, electric, etc. |
- Swing Type
- Working pressure: 200psi WOG
- Body: ASTM A351 Gr. CF8M
- Disc: ASTM A351 Gr. CF8M
- Packing: PTFE
- End Connections: Female NPT Threaded
Parts of Non-Return Valve
It is consists of body, cover, disk, hinge pin, and seat ring. In
the image below you can see the parts of the valve.
Types of Valves
The type of disk will decide the type of valve. Most common types
of Check valves are
- Swing Type.
- Lift Type
- Dual Plate Type
- Stop Check Valve
Swing Check Valve
The disc in a swing type valve is unguided as it fully opens or
closes. This Valve operates when there is flow in the line and get
fully closed when there is no flow. Turbulence and pressure drop in
the valve is very low. Disk and seat designs can be of metal to
metal or metal to composite.
Tilting Disc Check Valve
The tilting disc type valve is designed to overcome some of the
weaknesses of conventional swing type valves. The design of the
tilting disk enables the valve to open fully and remain steady at
lower flow rates and close quickly when the forwarding flow stop.
Ball Type and Plug Type Lift NRV
The seat design of a lift Check valve is similar to a Globe valve.
A piston or a ball is usually used as a disk.
Lift Check valves are particularly suitable for high-pressure
service where the velocity of flow is high. The disk is perfectly
set on the seat with full contact. They are suitable for
installation in horizontal or vertical pipelines with upward flow.
Dual Plate / Dual Disc Check Valve
A dual plate check valve is known as a butterfly check valve,
Folding Disc Check Valves, double-disc, or splits disc check valve.
As the name suggests, two halves of the disk move towards
centreline with the forward flow and with reverse flow two halves
open and rest on the seat to close the flow (Flapping action).
Stop Check Valve
Stop Check Valve is a combination of a lift check valve and a globe
valve. It can either be used as a check valve or as an isolation
(stop) valve like a globe valve. These valves can be closed with
the help of a stem that is not connected to the valve disc during
normal operation and make it possible to use these valves as a
regular NRV.
