Types Of Sanitary Check Valve

1. Sanitary Check Valve
- The disc of this type of check valve moves along the vertical centerline of the valve body. Like a vertical elevator, the disc can only move up or down. When the medium flows in the forward direction, the force of the medium pushes the disc open, much like a person inside an elevator door pushing it open, allowing the medium to pass through smoothly. When the medium stops flowing or reverses flow, the disc quickly closes due to its own weight and the pressure differential between the medium, much like an elevator door automatically closing to prevent entry. This type of check valve is suitable for small-diameter pipes. During installation, ensure that the disc can rise and fall freely without obstruction.
2. Swing Check Valve
- The disc of a swing check valve rotates around a pin. Imagine a door rotating on its hinge; the disc is like that door. When the medium flows in the forward direction, the medium pushes the disc open, allowing it to rotate smoothly, just like a door being gently pushed open. When the medium flows in the reverse direction, the disc quickly closes under its own weight and the pressure of the medium. This type of check valve is suitable for large-diameter pipes and offers the advantage of relatively low flow resistance. However, during installation, ensure that the disc's pivoting axis is securely fastened. Otherwise, it will affect proper operation, much like a door with loose hinges.
3. Butterfly Check Valve
- A butterfly check valve is structured like a butterfly. The disc is a circular disc, like a butterfly's wings. When the medium flows in the forward direction, the disc is pushed open by the medium, much like a butterfly's wings spread in the wind. When the medium flows in the reverse direction, the disc quickly closes. This type of check valve is small, lightweight, and relatively inexpensive. During installation, ensure that the flow direction of the medium in the pipeline aligns with the direction indicated on the disc. Otherwise, it will fail to function properly, like a butterfly flying against the wind.
4. Wafer Check Valve
- A wafer check valve is a compact check valve. It resembles two tightly sandwiched slices of bread, secured to the center of the pipeline by bolts and other fasteners. This type of check valve is quick and easy to install, saving space. Its operating principle is similar to other check valves: the disc opens during forward flow and closes during reverse flow. However, special attention must be paid to sealing during installation. A poor seal, like a gap between two slices of bread, can cause leakage and affect the operation of the entire system.

5. Slow-closing Check Valve
- A slow-closing check valve is unique, primarily designed to prevent water hammer. It acts like a gentle guardian. When forward flow ceases, it does not suddenly close the disc like other check valves, but rather slowly closes. This is like a car slowing down rather than suddenly braking. This type of check valve is particularly useful in piping systems sensitive to pressure surges. During installation, parameters such as the slow-closing time should be adjusted according to the manufacturer's specifications.