Check valve
Judberd is a professional supplier of check valves, our check valves include swing check valve，wafer check valve，ball check valve，silent check valve, tilting disc check valve and foot valve (foot valve is a special check valve with strainer in the inlet end),If you want to buy good quality gate valve for water, feel free to let us know.
What is check valve?
Check valves are mainly installed where the water is allowed to flow in one direction only, back ward flow is prohibited.and the valve opens when the water is flowing in the correct direction. If there is a back flow of water, the valve closes. This way, water can’t flow backwards ,if water flow back wards, it will cause damage to pumps, valves and other facilities .
Where are check valve used?
Check valve belongs to the pipeline system fittings, is the main role in a variety of pipeline fluid parts, its role is mainly three points, to prevent the back flow of fluid, to prevent the pump and drive motor reversal, to prevent the release of the container medium, suitable for a variety of industrial pipelines and water supply and drainage systems, domestic water pipeline network and other fields.
Often will use the check valve occasions are mainly.
1,High-rise building water supply network.
2,There are certain chemically corrosive media pipeline network.
3,Sewage network.
4,Water supply and drainage system.
5,Submersible, drainage, sewage pumps.
6,Living water pipeline network.
7,Pipelines of petroleum, chemical, metallurgy and other industrial sectors.
Types of Check Valves and Their Applications
Check valves are devices that allow fluid to flow in only one direction. There are many different types of check valves, each with its own advantages and disadvantages.
Swing check valves can be made to work at very high pressures, up to 42MPa, and can also be made to a large diameter, up to 1200mm or more. Depending on the material of the shell and seals, they can be used for any working medium and any working temperature range. The media are water, steam, gas, corrosive media, oil, food, pharmaceuticals, etc. The working temperature range of the medium is between -196~560℃.
The installation position of the swing check valve is not limited, usually installed in the horizontal pipeline, but can also be installed in the vertical pipeline or inclined pipeline.
The wafer check valve is suitable for low pressure and large diameter, and the installation occasion is restricted. Because the working pressure of the wafer check valve can not be very high, but the nominal diameter can be very large, can reach more than 1200mm, but the nominal pressure should smaller than 6.4MPa The wafer check valve can be made into a pair of clamping type, generally installed in the pipeline between the two flanges, using the form of clamping connection.
The ball check valve has a good sealing performance, reliable operation and good resistance to water strikes because the seal is a rubber covered sphere; and it can be made into a large diameter because the seal can be a single ball or multiple balls. However, the seal is a rubber-coated hollow sphere, which is not suitable for high pressure pipelines, but only for low and medium pressure pipelines.
The silent check valve is a check valve with a spring inside. When the medium flows in one direction, the flap is forced open by the pressure of the medium, and when the medium flows in the other direction, the flap is closed by the action of the spring, so as to achieve the purpose of preventing back flow. The silent check valve is suitable for use in pipelines with high back pressure, or where it is not allowed to produce water hammer noise when the medium flows in the reverse direction.
The diaphragm check valve is suitable for use in a pipeline where the medium is corrosive or contains suspended particles, because the seal is a flexible non-metallic membrane. The diaphragm check valve can also be made into a metal-to-metal seal type, which is suitable for use in high pressure and high temperature pipelines.
The lift check valve is a check valve in which the flap is lifted up by the medium to open, and falls down by its own weight or by the action of the spring to close. The advantage of the lift check valve is that it can be made into a small diameter and can be used in a pipeline with a high back pressure.
The plug check valve is suitable for use in pipelines with high back pressure, because the seal is a metal plug. The disadvantage of the plug check valve is that it can not be made into a large diameter, and the maximum diameter is only 600mm.
The piston check valve is a check valve in which the seal is a piston. The advantage of the piston check valve is that it has good sealing performance and can be made into a large diameter. The disadvantage of the piston check valve is that it can not be used in pipelines with high back pressure.
Foot valves as a special check valve are generally installed only in the vertical line of the pump inlet and the medium flows from the bottom up.
Tilting check valve is a special check valve, its main feature is that it can be installed in any position of the pipeline.The valve flap closes quickly, the water hammer pressure is small, easy installation, smooth flow channel, small fluid resistance, sensitive action, good sealing performance, short stroke of the valve flap, small closing impact, overall structure, simple and compact, beautiful shape, long service life, high reliability.
Flap valve also called flap check valve,Normally installed to the end of the flange pipe, when there is pressure in the pipe, flush open the valve cover, the media out. When there is no pressure in the pipeline, the valve cover closes automatically by gravity.
Types of check valves for water
Swing check valve, ball check valve, wafer check valve, lift check valve, spring check valve, flap check valve, tilting disc check valve, foot valve
What are common check valve problems?
Water hammer is a common problem when using swing check valves, water hammer is caused by the sudden closure of the valve, causing the water to flow backwards, hitting the valve plate and then stirring, repeatedly impacting in the pipeline, although the impact is getting smaller and will disappear in a short time, but the water hammer damage to the pipe fittings, valves, pumps and other facilities is huge. It may even cause the pipe to break or leak. Therefore, to avoid water hammer, we can improve the following aspects
1, Install lever and weight on the check valves and add cylinders if necessary
2, Use tilting check valve
3, Use a spring check valve (silent check valve)
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