Classification of check valves

Check valves can be classified into different types based on various factors such as the design, material used, application, and mechanism of operation. Here are some common types of check valves:

1. Swing check valve: It has a disc that swings on a hinge or a pin to allow flow in one direction and prevent backflow in the opposite direction. It is commonly used in water and wastewater applications.

2. Ball check valve: It uses a ball to control the flow direction. The ball is forced against the valve seat by the fluid pressure to prevent backflow. It is commonly used in high-pressure applications.

3. Piston check valve: It has a piston that moves up and down to control the flow direction. It is commonly used in low-pressure applications.

4. Diaphragm check valve: It uses a flexible diaphragm to control the flow direction. The diaphragm is forced against the valve seat by the fluid pressure to prevent backflow. It is commonly used in chemical and pharmaceutical applications.

5. Wafer check valve: It is designed to be sandwiched between two flanges and held in place by bolts. It is commonly used in HVAC and plumbing systems.

6. Dual plate check valve: It has two plates that open and close in response to the flow direction. It is commonly used in oil and gas applications.

7. Lift check valve: It uses a disc that lifts off the valve seat to allow flow in one direction and prevents backflow in the opposite direction. It is commonly used in steam and high-temperature applications.

8. Tilting disc check valve: It has a disc that tilts on a hinge to allow flow in one direction and prevent backflow in the opposite direction. It is commonly used in power generation and industrial applications.

These are some common types of check valves, but there are many other variations based on different factors.