A check valve is also known as a clack valve, one-way valve, or non-return valve as it allows fluid to flow in one direction only. These industrial valves are automatically activated by the force produced by the flow of the medium itself through the pipeline and can be classified as an automatic valve. The check valves are being used in pipeline systems, their key functions are to prevent the medium from flowing back, to prevent the pump and its generator from reversing, and to prevent the medium from flowing back from the container. The check valve may also be used to substitute the auxiliary system at which pressure can increase above the pressure of the main system. If the flow reverse and no check valve is fitted, water hammer can take place. Water hammer often occurs with excessive force and can easily damage the pipeline or parts.