Check valve refers to a valve whose opening and closing parts are circular discs and rely on their own weight and medium pressure to act to block the reverse flow of the medium. It belongs to the automatic valve category, also known as one-way valve, return valve or isolation valve.
The function of this type of valve is to allow the medium to flow in one direction only and prevent the flow in the opposite direction. Usually this kind of valve works automatically. Under the pressure of fluid flowing in one direction, the valve disc opens; when the fluid flows in the opposite direction, the fluid pressure and the self-weight of the valve disc act on the valve seat, thereby cutting off the flow. Only allowing media to flow in one direction is to prevent accidents.
Check valves are divided according to their structures and connection forms.Different check valves can be used in different places.TWT,China will introduce it to buyers,and take a typical one as an example.
Wafer dual plate check valve is used in pure pipelines and industrial, environmental protection, water treatment, and high-rise building water supply and drainage pipelines to prevent the reverse flow of media.Wafer dual plate check valve adopts a wafer type, the butterfly plate is two semicircles, and is forced to return by a spring. The sealing surface can be made of wear-resistant material surfacing on the body or lined with rubber. It has a wide range of use and reliable sealing.
Structures of check valves
1. Lift check valve:
It can be divided into vertical and horizontal types. Its valve body style is the same as that of the stop valve, so the fluid resistance is very large. The vertical media outlet pipe is the same as the valve seat pipe, so the flow resistance is much smaller than that of the straight-through type. It is usually installed on the vertical pipeline. The straight-through type is generally installed on horizontal pipes, and due to installation restrictions, it can only be used when the diameter is less than 50 DN.
2. Swing check valve:
Its internal channel is streamlined, so the resistance is lower than that of the lifting type. It is usually used on small and medium-diameter and low-pressure large-diameter pipelines, and its sealing performance is not as good as that of the lifting type. It can be divided into three categories: single valve, double valve, and multi-valve type depending on the diameter of the valve door. It can mainly play the role of reducing the impact of water flow when stopping the flow or reversing the flow. The single-flap type is normally installed on medium-diameter pipelines, the double-flap type is used on large- and medium-diameter pipelines, and the multi-flap type is used on large-diameter pipelines.
3. Butterfly check valve:
Its structure is similar to that of a butterfly valve. It is relatively simple, with low flow resistance and small water hammer pressure. It is usually installed on horizontal pipelines and has poor sealing performance.
Connection of butterfly valves
1. Flange butterfly valve
Flange connection is the most common connection method for check valves. The flange check valve connects the check valve and the flange through the flange plate to form a whole. The flange check valve can be fixed on the pipeline through the connected flange and can be easily disassembled. Flange check valves are widely used in pipelines and equipment transporting industrial media such as oil, gas, water, and steam.
2. Threaded butterfly valve
Threaded connection is a common connection method for check valves. Threaded check valves are usually used on small pipelines and equipment. The connection method is simple. Common threaded connections include internal threads and external threads, which are easy to install and disassemble.
3.Wafer dual plate check valve
A wafer connection is a method of connecting a check valve to a pipe. The wafer dual plate check valve generally consists of two ferrules and a packing pad. During installation, the ferrules are clamped at both ends of the pipeline, and then the packing pads are clamped in the ferrules. The wafer dual plate check valve is fixed on the pipeline through bolts. . The clamp connection has the advantages of tight connection and easy disassembly.
4. Welding butterfly valve
Welded connections are generally used in high-temperature, high-pressure industrial production situations. Welded check valves are welded together with pipelines. Because the welded connection has the advantages of tightness and solidity, it is widely used in petroleum, chemical and other industries.
Features of wafer dual plate check valve
Wafer dual plate check valve is suitable for various pipelines with nominal pressure PN1.0MPa~42.0MPa, nominal diameter DN15mm~1200mm, NPS1/2”~48”; operating temperature -196C~540C, used to prevent Medium flow back. By selecting different materials, the double-leaf butterfly check valve can be applied to various media such as water, steam, oil, nitric acid, strongly oxidizing media and urea.
Wafer dual plate check valve mainly has the characteristics of compact structure, convenient installation and convenient operation, and is widely used.
China wafer dual plate check valve
TWT specializes in the production of wafer dual plate check valve and other valves, and our quality and service have been praised for many years. If you have any needs or questions, please feel free to call us. We look forward to your call in beautiful Tianjin, China.