A check valve or a non return valve is a device that allows the flow of water or other material in only one direction, it will stop the flow in the opposite direction. Check valves are installed in pipe lines and do not require any activation from the outside. Check valves sense when material is moving in the opposite direction and it will plug the pope to prevent the movement.

Check valves are used in several types of devices,  for instance they can be used in water heaters and sump pumps but can also be used with control valves, strainers, and flow meters.

Some different types of Check valves are:

• Ball - This type is the most common, a ball in the valve sits tightly against the valve where the material comes in. A spring holds the ball in place and helps seal the opening - water flowing through the pipe will push the ball against the spring allowing water to flow through - when the flow is cut off the ball is pushed back by the spring to stop any backflow of material.
• Cone - A cone valve is similar to a ball valve except the plug is shaped like a cone, these can also be called a lift check valve. The cone valve is designed with a cone that is held on a bar which will raise up when water or material flows through the pipe, it will then drop in place when the flow stops, if material was to flow backwards this would push against the cone and create a seal preventing it from going any further.
• Disk - These valves operate in the same way the ball and cone valves work except the plug is a disk shape that is connected with a hinge - the material will force the flap open and when it's turned off the flap goes back in place stopping any backflow - this type can and may affect the flow because the flap rides on top of the material creating drag. Disk valves are prone to more wear and tear because of the many parts involved in them - these are also known as swing check valves.

Check valves are very important when flow of material needs to be restricted - any one of these types will work for your application.

Kscdirect.com offers a large supply of check valves, contact a salesman today.