Threaded Check Valve

1. Basic structure and principle of operation
● Structure: Mainly consists of valve body, valve disc (or ball), spring (optional) and threaded interface.

● Working Principle:

● When the medium flows forward, the pressure pushes the valve disc and the valve opens.

● When the medium flows back (reverse flow), the valve disc will automatically close by gravity, spring force, or medium pressure to prevent backflow.

2. Main types (classified by structure)

1. Lifting Check Valve (Vertical/Horizontal)

● The valve disc moves vertically or horizontally, suitable for higher pressure, but you should pay attention to the direction of flow when installing (horizontal installation is usually required).

2. Rotary check valve

● The valve disc swings like a door plate, suitable for more flow, but there may be water hammer when closing.

3. Spring Check Valve (Silent Check Valve)

● Built-in spring helps to close to reduce the impact of water hammer, suitable for piping systems with frequent starts and stops.

4. Ball Check Valve

● Adopts spherical valve core with good sealing performance, suitable for high-viscosity or particle-containing media.

3. Main characteristics
✅ Threaded connection (G/NPT standard), easy installation, suitable for small diameter DN15-DN50 pipes.

Automatic opening and closing, no manual control required to prevent the backflow of the medium.

Low flow resistance (compared to shut-off valve), energy-saving and efficient.
✅ Additional materials: cast iron, cast steel, stainless steel (304/316), brass, etc., to adapt to different environments.
❌ Not suitable for large diameter and high pressure pipelines (normal PN≤1.6 MPa).

4. Applicable Standards
● National Standard (GB): GB/T 8464 (Common Valve), GB/T 12233 (Iron Shut-off Valve and Check Valve).

● American Standard: ANSI B16.34 (Pressure and Temperature Grade), NPT Thread Standard.

● European Standard: EN 12334 (Check Valve Requirements).