The purpose of using a check valve is to prevent the reverse flow of the medium, and a check valve is generally installed at the outlet of the pump. In addition, a check valve should also be installed at the outlet of the compressor. In short, in order to prevent the reverse flow of the medium, a check valve should be installed on the equipment, device or pipeline.
Generally, vertical lift check valves are used on horizontal pipelines with a nominal diameter of 50mm. Straight-through lift check valve can be installed on both horizontal and vertical pipelines. The bottom valve is generally only installed on the vertical pipeline of the pump inlet, and the medium flows from bottom to top.
Swing check valve can be made into very high working pressure, PN can reach 42MPa, and DN can also be made very large, the maximum can reach more than 2000mm. According to the different materials of the shell and seal, it can be applied to any working medium and any working temperature range. The medium is water, steam, gas, corrosive medium, oil, food, medicine, etc. The working temperature of the medium is between -196~800℃.
The installation position of the swing check valve is not limited, it is usually installed on the horizontal pipeline, but it can also be installed on the vertical pipeline or the inclined pipeline.
The applicable occasion of butterfly check valve is low pressure and large diameter, and the installation occasion is limited. Because the working pressure of the butterfly check valve cannot be very high, but the nominal diameter can be very large, which can reach more than 2000mm, but the nominal pressure is below 6.4MPa. The butterfly check valve can be made into a wafer type, which is generally installed between the two flanges of the pipeline in the form of wafer connection.
The installation position of butterfly check valve is not limited, it can be installed on horizontal pipeline, vertical pipeline or inclined pipeline.
Diaphragm check valve is suitable for pipelines that are prone to water hammer. The diaphragm can well eliminate the water hammer caused by the reverse flow of the medium. Since the working temperature and operating pressure of diaphragm check valves are limited by the diaphragm material, they are generally used in low-pressure and normal-temperature pipelines, especially for tap water pipelines. Generally, the working temperature of the medium is between -20~120℃, and the working pressure is less than 1.6MPa, but the diaphragm check valve can achieve a larger diameter, and the maximum DN can be more than 2000mm.
Diaphragm check valve has been widely used in recent years due to its excellent waterproof performance, relatively simple structure and low manufacturing cost.
The ball check valve has good sealing performance, reliable operation and good water hammer resistance because the seal is a sphere covered with rubber; and because the seal can be a single ball or multiple balls, it can be made into a large diameter . However, its seal is a hollow sphere covered with rubber, which is not suitable for high-pressure pipelines, but only suitable for medium and low-pressure pipelines.
Since the shell material of the ball check valve can be made of stainless steel, and the hollow sphere of the seal can be covered with PTFE engineering plastic, it can also be used in pipelines with general corrosive media.
The working temperature of this type of check valve is between -101~150℃, the nominal pressure is ≤4.0MPa, and the nominal diameter range is between 200~1200mm.
Post time: Mar-23-2022
