Where the check valve is applicable

Author:check valve     Published time:2018-11-15 08:10     Reading times:369    

China check valves are versatile and powerful, and high-quality check valves play a huge role in pipeline fluids. Check valves are often used as bottom valves for pumping devices to prevent backflow of water. The combination of the stop valve and the shut-off valve provides a safe isolation.


The purpose of using a check valve is to prevent back flow of the medium, and a check valve is generally installed at the outlet of the pump. In addition, a check valve is also installed at the outlet of the compressor. In summary, in order to prevent backflow of the medium, a check valve should be installed on the equipment, equipment or piping.


Vertical lift check valves are generally used on horizontal pipes with a nominal diameter of 50 mm. Straight-flow lift check valves are available for both horizontal and vertical lines. The bottom valve is typically mounted only on the vertical line of the pump inlet and the medium flows from bottom to top.


The swing check valve can be made to work at a very high working pressure, PN up to 42 MPa, and the DN can be made very large, up to 2000 mm or more. Depending on the material of the housing and the seal, any working medium and any operating temperature range can be applied. The medium is water, steam, gas, corrosive medium, oil, food, medicine, and the like. The media operating temperature range is between -196 and 800 °C.


The swing check valve is installed in an unrestricted position and is usually installed on a horizontal pipe, but it can also be installed on a vertical pipe or a slanted pipe.


The application of the butterfly check valve is low pressure and large diameter, and the installation is limited. Because the working pressure of the butterfly check valve can not be very high, but the nominal diameter can be very large, can reach 2000mm or more, but the nominal pressure is below 6.4MPa. The butterfly check valve can be made into a clip type, generally installed between the two flanges of the pipeline, in the form of a clip connection.


The butterfly check valve is installed in an unrestricted position and can be installed on a horizontal pipe or on a vertical pipe or a slanted pipe.


The diaphragm check valve is suitable for pipes that are prone to water hammer, and the diaphragm can well eliminate the water hammer generated when the medium flows back. Since the operating temperature and the use pressure of the diaphragm type check valve are limited by the diaphragm material, it is generally used on a low pressure normal temperature line, and is particularly suitable for a water pipe. Generally, the working temperature of the medium is between -20 and 120 °C, and the working pressure is <1.6 MPa. However, the diaphragm type check valve can achieve a larger diameter, and the DN can be up to 2000 mm or more.


The diaphragm type check valve has many applications in recent years due to its excellent waterproof performance, simple structure and low manufacturing cost.


Since the sealing member is a rubber-coated sphere, the sealing performance is good, the operation is reliable, and the water hammer resistance is good; and since the sealing member can be a single ball or a multi-ball, it can be made into a large diameter. . However, its seal is a rubber-coated hollow sphere that is not suitable for high-pressure pipelines and is only suitable for medium and low pressure pipelines.


Since the shell material of the ball check valve can be made of stainless steel, the hollow sphere of the seal can be coated with PTFE engineering plastic, so it can also be applied to the pipeline of general corrosive medium.


The operating temperature of this type of check valve is between -101 and 150 °C, the nominal pressure is ≤4.0 MPa, and the nominal diameter is between 200 and 1200 mm.


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