Differences Between Lift Check Valve, Swing Check Valve, and Butterfly Check Valve

A lift check valve is a type of check valve where the valve disc slides along the vertical centerline of the valve body.

It can only be installed in horizontal pipelines. In high-pressure, small-diameter check valves, the valve disc may be a spherical ball.

The shape of the valve body is similar to that of a globe valve (so they can be interchangeable), which leads to a relatively high flow resistance coefficient. Its structure is similar to a globe valve, with the valve body and disc being the same as those of a globe valve. The upper part of the valve disc and the lower part of the valve cover are equipped with guide sleeves.

The valve disc guide sleeve can move freely up and down within the valve body’s guide sleeve. When the fluid flows in the forward direction, the valve disc opens due to the push from the fluid’s thrust. When the fluid stops flowing, the valve disc drops under its own weight to the valve seat, preventing reverse flow of the fluid.

The straight-through lift check valve has an inlet and outlet channel perpendicular to the valve seat channel, while the vertical lift check valve has the inlet and outlet channel in the same direction as the valve seat channel, resulting in lower flow resistance compared to the straight-through type.

The valve disc of a swing check valve is disc-shaped and rotates around the valve seat's axis.

Because the internal flow passage is streamlined, the flow resistance is lower than that of a lift check valve. Swing check valves are suitable for low-flow speed and large-diameter applications where flow changes are infrequent, but they are not recommended for pulsating flows.

Their sealing performance is not as good as that of lift check valves. Swing check valves can be classified into single-disc, double-disc, and multi-plate types, depending on the valve size. The purpose of these forms is to reduce hydraulic shock when the fluid stops flowing or reverses.

The wafer check valve has a structure similar to that of a butterfly valve, with the main difference being that a butterfly valve is a shut-off valve requiring external driving forces, while a wafer check valve is an automatic valve that does not require a driving mechanism.

When the fluid flow stops or reverses, the disc rotates to the valve seat due to its own weight and the backward flow of the medium.

This type of check valve can be used in both horizontal and vertical pipelines and is typically installed in a wafer-style arrangement. The two valve discs rotate around a pin axis under the action of fluid pressure, overcoming spring force, and the valve opens in a state resembling the ">" symbol. A certain length of straight pipe must be left at both the inlet and outlet to provide sufficient rotational space for the valve disc.