Check valves are unidirectional valves that ensure media flows in only a single direction. There are several check valve styles that perform unidirectional media flow like a ball, piston, or disk style. A ball check valve can prevent the backflow of various media like gas, air, steam, vapor, or water lines with high flow velocities. This article discusses the basic functions of a check valve, concentrating on the working and installation of a ball check valve.
A check valve is a device that allows the flow of fluids in only one direction. They have two ports, an inlet and an outlet. Since they only allow media flow in one direction, they are commonly referred to as ‘one-way valves’ or ‘non-return valves.’ The main purpose of a check valve is to prevent backflow in a system.
The valve relies on a pressure differential to work. To open, It requires a higher pressure on the input side of the valve than on the output side. The valve will close when the pressure is higher on the output side (or the input side pressure is not high enough to keep the valve open). Depending on the valve type, the closure mechanism is different. Unlike other valves, they do not need a handle, lever, actuator, or human to work.