What Is an Inline Check Valve?
An inline check valve is a valve that is inserted inside a pipe to prevent backflow. When fluid at a pressure greater than or equal to the preset pressure reaches the inline check valve in relation to the direction of flow of the inline check valve, the valve opens, and the fluid flows. In the case of reverse flow or fluid flow below the preset pressure, the valve will not open, and the fluid will not flow. Many products are characterized by the fact that they do not require external momentum, such as electric power, and operate solely on the internal mechanism.
Uses of Inline Check Valves
Inline check valves are used in various applications, including chemical and petroleum plant factories, machine tools that use lubricants and abrasives, household products, and public institutions such as waterworks and water treatment plants. When selecting an inline check valve, it is necessary to consider such factors as the set pressure to allow the fluid to pass through the valve’s inside diameter, the magnitude of the fluid loss coefficient, construction, allowable flow and pressure, vibration, and ease of maintenance. It is also necessary to consider whether the material is compatible with the type of fluid used.
Principles of Inline Check Valves
The following explains the principle of operation of an inline check valve. Inline check valves consist of a seat affixed to the side of the piping to provide thickness. This component is called a poppet that normally inhibits flow and, under certain conditions, allows flow through a spring to keep the poppet in contact with the seat by applying force in a direction that keeps it in contact with the seat, and a seat affixed to the side of the piping to hold that spring in place. The seat is used to hold the poppet in place.
While the inline check valve is operating, if a pressure more significant than the force exerted by the spring in the flow direction is applied by the fluid, the spring is pushed together with the poppet, allowing the fluid to flow through the inline check valve. The poppet will not open unless the flow applies a pressure greater than the force exerted by the spring. If flow occurs in the reverse direction, the poppet is pushed by the flow in the direction of the seat, so the higher the pressure exerted on the poppet by the flow, the more it will inhibit the flow.