Check valve is also known as reverse flow valve, check valve, back pressure valve and one-way valve. This type of valve automatically opens and closes by the force generated by the flow of the medium in the pipeline. It is an automatic valve.
Check valve refers to a valve that relies on the flow of the medium itself to automatically open and close the valve disc to prevent the medium from flowing back. It is also called a check valve, one-way valve, reverse flow valve and back pressure valve. The check valve is an automatic valve whose main function is to prevent the backflow of the medium, the reverse rotation of the pump and drive motor, and the release of the container medium. Check valves may also be used on lines supplying auxiliary systems where the pressure may rise above the system pressure. Check valves can be mainly divided into swing check valves (rotating according to the center of gravity) and lift check valves (moving along the axis).
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.
Wafer check valve uses:
The check valve is installed in the pipeline system. Its main function is to prevent the backflow of the medium. The check valve is an automatic valve that relies on the pressure of the medium to open and close. Wafer check valve is suitable for various pipelines with nominal pressure PN1.0MPa~42.0MPa, Class150~25000; nominal diameter DN15~1200mm, NPS1/2~48; operating temperature -196~540℃, used to prevent Medium flow back. By choosing different materials, it can be used in various media such as water, steam, oil, nitric acid, acetic acid, strong oxidizing media and uric acid.
Structural features of clamp check valve:
1. Short structural length, its structural length is only 1/4~1/8 of traditional flange check valves.
2. Small size and light weight, its weight is only 1/4~1/20 of traditional flange check valves.
3. The valve disc closes quickly and the water hammer pressure is small.
4. Both horizontal and vertical pipelines can be used and are easy to install.
5. Smooth flow channel and small fluid resistance.
6. Sensitive action and good sealing performance.
7. The valve disc has short stroke and small closing impact force.
8. The overall structure is simple and compact, and the shape is beautiful.
9. Long service life and reliable performance.
The function of the check valve in the water pump water supply system is to prevent the backflow of high-pressure water from impacting the water pump impeller. When the water pump suddenly stops running for some reason during the operation of the system, the pressure in the pump disappears, and the high-pressure water connected to the water pump outlet will flow back to the water pump in the reverse direction. When the water pump outlet is equipped with a check valve, it will close immediately to prevent high-pressure water from flowing back into the water pump in the reverse direction.
The function of the check valve in the hot water system is to prevent hot water from flowing back into the pipes. If it is a PVC pipe, it is likely to burn the pipe and even injure people, especially in solar water heater systems.
Lift check valve:
Lift check valve is a check valve whose disc slides along the vertical centerline of the valve body. On high-pressure small-diameter check valves, the disc can be made of round balls. The valve body shape of the lift check valve is the same as that of the stop valve (can be used universally with the stop valve), so its fluid resistance coefficient is larger. Its structure is similar to that of a globe valve, and its valve body and 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 processed with a guide sleeve. The valve disc guide sleeve can be freely raised and lowered in the valve cover guide sleeve. When the medium flows forward, the valve disc opens by the thrust of the medium. When the medium stops flowing, the valve disc falls by its own weight. On the valve seat, it prevents the reverse flow of medium.
Straight-through lift check valve:
The direction of the medium inlet and outlet channels is perpendicular to the direction of the valve seat channel. The lift-type horizontal flap check valve can only be installed on horizontal pipelines, and is generally available on horizontal pipelines with a nominal diameter of 50mm.
Vertical lift check valve:
The direction of the medium inlet and outlet channel is the same as that of the valve seat channel. The lift-type vertical flap check valve can only be installed on vertical pipes, and its flow resistance is smaller than that of the straight-through type.
The lifting type has better sealing and greater fluid resistance than the swing type.
Resistance value: Straight-through lift check valve>vertical lift check valve>swing check valve
Butterfly check valve:
The installation position of the butterfly check valve is not restricted and can be installed on horizontal pipelines, vertical or inclined pipelines.
Micro-resistance slow-closing butterfly check valve:
It is mainly composed of a valve body, two semicircular valve discs, a return spring, an oil storage cylinder, a slow-closing small cylinder group, and a needle valve (micro-control valve). It can be used in drainage pipelines of clean water, sewage, seawater and other media. It can not only prevent the backflow of media, but also effectively limit destructive water hammer and ensure the safety of pipelines. It is not suitable for granular media containing solid particles and high viscosity. It is small in size, light in weight and only about one-third of the length of the swing check valve.
Product performance features:
When the medium flows forward through the valve, the butterfly plate is opened due to the pressure of the medium itself. The pressure water in the pipeline compresses the oil in the spherical rubber oil pool through the small hole in the valve body. The oil passes through the oil pipe through the oil cylinder and pushes the piston out. , and at the same time, because the butterfly plate is subject to the double reaction force of the torsion spring and piston assembly, the opening of the butterfly plate is relatively slow.
When the medium flows in the opposite direction, the weight of the butterfly plate itself, the elastic force of the torsion spring and the force of the counter-flow medium make the butterfly plate move in the closing direction. When the butterfly plate moves to the piston (about 80% closed), due to the hydraulic action of the piston assembly, the butterfly plate is prevented from closing quickly. The oil in the cylinder is adjusted through the oil pipe and the needle valve, and then returns to the oil pool. The plate slowly closes until it completely matches the sealing surface. In this process, the slow closing and silencing function of the check valve is realized, and at the same time, the reverse flow of the medium is effectively prevented. By adjusting the needle valve, the slow closing of the butterfly plate can be changed. The length of time.
