Check Valve

Types of Check valves

Swing Check valve
A basic swing Check valve consists of a valve body, a bonnet, and a disk that is connected to a hinge. The disk swings away from the valve-seat to allow flow in the forward direction, and returns to valve-seat when upstream flow is stopped, to prevent backflow. The disc in a swing type check valve is unguided as it fully opens or closes.

Lift Check or Piston valve
The seat design of a lift-check valve is similar to a globe valve. The disc is usually in the form of a piston or a ball. Lift check valves are particularly suitable for high-pressure service where velocity of flow is high. In lift check valves, the disc is precisely guided and fits perfectly into the dashpot. Lift check valves are suitable for installation in horizontal or vertical pipe-lines with upward flow.

Valve connections

There are a various methods used for connecting valves into the piping systems. They are as follows:

• Flanges: Suitable rated flanges are provided with the pipe valve.
• Wafer: The pipe valve is provided with suitable sealing faces. It is trapped between line flanges.
• Butt Welded: The pipe valve is provided with butt weld end. This is welded into the piping system using high integrity joints.
• Socket Welded: These welds allow and weld into the piping system using fillet welds.
• Screwed Ends: Ends of pipe valves can be provided with female or male screwed ends . The threads can be parallel or tapered.
• Compression Fittings: Ends of pipe valves can be provided with compression fittings.