Structural features of butterfly check valve

Butterfly check valves include swing check valves and lift check valves. A swing check valve has a hinge mechanism and a disc like a door that rests freely on the inclined surface of the valve seat.

　　Swing check valves include swing check valves and lift check valves. A swing check valve has a hinge mechanism and a valve disc like a door that rests freely on the inclined valve seat surface. To ensure that the valve disc reaches the proper position on the valve seat surface each time, the valve disc is designed in a hinge mechanism so that the valve disc has enough swing space and makes the valve disc truly and fully contact the valve seat. The valve disc can be made entirely of metal, or it can be inlaid with leather, rubber, or a synthetic covering on the metal, depending on the performance requirements. Swing check valves, when fully open, offer almost no obstruction to fluid pressure, so the pressure drop across the valve is relatively small. The disc of the lift check valve is located on the valve seat sealing surface of the valve body. Except that the valve disc can move up and down freely, the rest of this valve is like a globe valve. The fluid pressure lifts the valve disc from the valve seat sealing surface, and the backflow of the medium causes the valve disc to fall back onto the valve seat and cut off the flow. Depending on the conditions of use, the valve disc can be of all-metal construction, or it can be in the form of a rubber pad or rubber ring inlaid on the valve disc holder. Like globe valves, the passage of fluid through lift check valves is also narrow, so the pressure drop through lift check valves is greater than that of swing check valves, and the flow of swing check valves is less restricted. This type of valve should generally be installed horizontally in the pipeline.

　　Check valves can be divided according to their structure and installation method:

　　1. The disc of the butterfly check valve is disc-shaped and rotates around the axis of the valve seat passage. Because the passage inside the valve is streamlined, the flow resistance is smaller than that of the lift butterfly check valve. It is suitable for large-diameter applications with low flow rates and infrequent flow changes, but it is not suitable for pulsating flows. Its sealing performance is not as good as that of the lift type. Butterfly check valves are divided into three types: single-disc, double-disc, and multi-disc. These three forms are mainly divided according to the valve port diameter in order to weaken the water hammer when the medium stops flowing or flows back.

　　2. Butterfly check valve: divided into two types according to the working form of the valve disc: 1. A check valve in which the valve disc slides along the vertical center line of the valve body. The butterfly check valve can only be installed on a horizontal pipeline. On a high-pressure, small-diameter check valve, the valve disc can be a ball. The valve body shape of the butterfly check valve is the same as that of the globe valve (can be used with the globe valve), so its fluid resistance coefficient is large. Its structure is similar to that of a globe valve, and the valve body and valve disc are the same as those of a globe 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 up and down freely in the valve seat guide sleeve. When the medium flows in the forward direction, the valve disc is opened by the thrust of the medium. When the medium stops flowing, the valve disc falls on the valve seat by its own weight to prevent the medium from flowing backward. The direction of the medium inlet and outlet channels of the straight-through butterfly check valve is perpendicular to the direction of the valve seat channel; the vertical lift check valve has the same direction of the medium inlet and outlet channels as the valve seat channel, and its flow resistance is smaller than that of the straight-through type; 2. A check valve in which the valve disc rotates around the pin shaft inside the valve seat. The butterfly check valve has a simple structure and can only be installed on horizontal pipelines, and its sealing performance is poor.

　　3. Pipeline check valve: A valve in which the valve disc slides along the center line of the valve body. The pipeline check valve is a new type of valve. It is small in size, light in weight, and has good processing technology. It is one of the development directions of check valves. However, the fluid resistance coefficient is slightly larger than that of the swing check valve.

　　4. Compression check valve: This valve is used as a valve for cutting off boiler water supply and steam. It has the comprehensive functions of a lift check valve and a globe valve or angle valve.

　　In addition, there are some check valves that are not suitable for pump outlet installation, such as foot valves, spring type, Y type and other check valves.

　　5. Usage and performance specifications:

　　This valve is used on industrial pipelines as a device to prevent backflow of media.

Check Valves and Their Applications

What is a stop valve?

Check Valves and Their Applications

What is a stop valve?

Shandong Gongchen Machinery Technology: Customizing high-quality auto casting OEM solutions for you

2024-01-03

Challenging the difficulties of auto casting OEM, we are your reliable partner

2023-11-16

An experienced auto casting OEM supplier, helping you achieve product differentiation

2023-10-29