Lift check valve: Structural features of the lift check valve:

The lift check valve disc moves up and down along a direction perpendicular to the center line of the pipeline, similar to the structure of a globe valve. It is usually composed of a valve body, valve disc, valve seat, and spring (or no spring).The lift check valve is designed to prevent backflow and is essential in various applications where safety and efficiency are paramount.

· Working principle of the lift check valve:

The upper part of the valve disc and the lower part of the valve cover are machined with guide sleeves. The valve disc guide sleeve can move freely up and down within the valve seat guide sleeve. When the medium flows in the direction, the valve disc opens under the thrust of the medium. When the medium stops flowing, the valve disc drops vertically onto the valve seat, preventing the reverse flow of the medium.

· advantage:

Good sealing performance, suitable for high-pressure and small-diameter pipelines.

· Simple structure,and easy to maintain.

· shortcoming ：

· The fluid resistance is large, and the opening pressure is required to be high.

· Not suitable for large diameter pipelines, because the valve disc stroke is short, fluid impact may lead to water hammer when closed.

· Applicable scenarios:

· Often used in small diameter, high-pressure, or high-sealing needs, such as water supply systems, steam pipelines, etc.

· Suitable for horizontal or vertical installation (vertical installation requires upward flow of fluid).

Swing Check Valve:

The valve disc rotates around the pivot of the valve seat. this design offers lower flow resistance compared to lift check valves. It is ideal for large-diameter applications with low flow rates and stable flow patterns, though it’s not recommended for pulsating flows. However, the sealing performance is not good as lift check valves.

· Structural characteristics:

The swing check valve is divided into three types: single disc, double disc, and multi disc. These three forms are primarily classified by valve opening diameter, designed to prevent the medium from stopping or backflowing, and to reduce hydraulic shock.

· Working principle:

The forward flow pushes the valve disc to rotate around the axis to open; in reverse flow, the valve disc closes by gravity or fluid pressure to prevent backflow.

· advantage：

· Low fluid resistance, suitable for a large diameter pipeline.

· The structure is suitable for a variety of installation methods (horizontal or vertical, with the fluid flowing downward when vertical).

· Suitable for low pressure and high flow.

· shortcoming ：

Water hammer may occur when the closure is closed, especially at large diameters or high flow rates. The sealing performance is slightly worse than the lifting type

. Applicable scenarios:

Often used in large diameter, low-pressure pipelines, such as sewage treatment, fire protection systems, large water transmission pipelines, etc. Not suitable for frequent switching or high-pressure systems.

wafer check valve:

Structural Features:

The wafer-type check valve shares structural similarities with butterfly valves, but differs in that, while butterfly valves require external force to operate as shut-off devices, wafer check valves function automatically without mechanical drive mechanisms. When the flow stops or backflow occurs, the disc rotates onto the valve seat due to gravity and the pressure of the backflow medium. This type of check valve can be installed horizontally or vertically, typically using a wafer-type mounting method.

Working principle:

The forward flow of fluid pushes the valve to rotate and open, and the reverse flow or spring force makes the valve close quickly to prevent backflow.

advantage：

Compact structure, small space occupied, suitable for a large diameter pipeline.

Low resistance, fast opening and closing speed. Light weight, low installation and maintenance costs.

Disadvantages:

The sealing performance is generally not suitable for high pressure or high sealing requirements. The valve disc may become impacted by fluid and wear out with prolonged use.

applicable scene ：

Often used in ventilation systems, air conditioning systems, low-pressure water systems, etc. Suitable for situations requiring rapid closure and low flow resistance.

Summary and comparison

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