A check valve may be defined as the mechanical device which is used to allow the stream of liquid or gas through the valve in single direction only. The most important type of check valve is the ball check valve. The ball check valves are check valves which have a spherical ball as the movable part for blocking the flow of fluids though them. Sometimes, in these valves, the ball is spring loaded in order to help in shutting. For other designs which do not have springs, in order to create a seal, the ball has to be moved towards the seat with the help of a reverse flow of fluids. The internal surface of the seats of the ball check valves are cone shaped in order to direct the ball in to the seat which forms a seal to stop the reverse flow of liquids.

Usage of ball check valves

The design of the ball check valves are simple and so they are very cheap. They are usually employed in liquid mini pump dispensers, manual air pumps, refillable dispensing syringes, spray devices etc. In most of the times, the balls are made up of metals. But sometimes, they can be made with other materials also such as artificial ruby. For instance, high pressure HPLC pumps usually use small ball check valves for both inlet and outlet where the balls are made up of artificial ruby. This is done in order to ensure hardness and chemical resistance.

After using for a long period, these ball check valves may wear out eventually and they require replacements. For this reason, the ball check valve is made up of easily replaceable materials that are cheap. For instance, sometimes the ball check valves are positioned in a plastic body which is fitted inside a metal vessel in order to counter the high pressure inside it. The ball check valve is not the same as ball valve. These two valves are often misinterpreted. In a ball valve, the ball acts as the rotor which is used to stop or direct the flow of liquid.