Applicable occasions for check valves

The purpose of using a check valve is to prevent backflow 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, to prevent backflow of the medium, check valves should be installed on equipment, devices, or pipelines.

Vertical lift check valves are generally used on horizontal pipelines with a nominal diameter of 50mm. The straight through lift check valve can be installed on both horizontal and vertical pipelines. Bottom valves are generally only installed on the vertical pipeline at the pump inlet, and the medium flows from bottom to top.

Swing check valves can be designed for high working pressures, with a PN of up to 42MPa and a DN of up to 2000mm or more. According to the different materials of the shell and seals, it can be applied to any working medium and any working temperature range. The medium includes water, steam, gas, corrosive medium, oil, food, medicine, etc. The working temperature range of the medium is between -196~800 ℃.

The installation position of the swing check valve is not limited, usually installed on horizontal pipelines, but it can also be installed on vertical or inclined pipelines.

The butterfly check valve is suitable for low-pressure large-diameter applications, and its installation is limited. Because the working pressure of butterfly check valves cannot be very high, but the nominal diameter can be very large, reaching over 2000mm, but the nominal pressure is below 6.4MPa. Butterfly check valves can be made into clamp type, usually installed between the two flanges of the pipeline, using a clamp connection form.

The installation position of butterfly check valve is not limited, it can be installed on horizontal pipelines, vertical pipelines or inclined pipelines.

Diaphragm check valves are suitable for pipelines that are prone to water hammer, and diaphragms can effectively eliminate water hammer caused by medium backflow. Due to the limitations of diaphragm materials on the working temperature and operating pressure of diaphragm check valves, they are generally used in low-pressure and room temperature pipelines, especially suitable for water pipelines. The working temperature of the general medium is between -20~120 ℃, and the working pressure is less than 1.6MPa. However, diaphragm check valves can achieve larger diameters, with a maximum DN of over 2000mm.

Diaphragm check valves have been widely used in recent years due to their excellent waterproof performance, simple structure, and low manufacturing cost.

Spherical check valves have good sealing performance, reliable operation, and good water hammer resistance due to the fact that the sealing element is a rubber coated sphere; Due to the fact that the seal can be a single ball or made into multiple balls, it can be made into a large diameter. But its sealing element is a hollow ball wrapped in rubber, which is not suitable for high-pressure pipelines, only suitable for medium and low-pressure pipelines.

Due to the fact that the shell material of the spherical check valve can be made of stainless steel, and the hollow sphere of the sealing element can be coated with polytetrafluoroethylene engineering plastic, it can also be applied in pipelines with general corrosive media.

The working temperature of this type of check valve is between -101~150 ℃, with a nominal pressure of ≤ 4.0MPa and a nominal diameter range of 200~1200mm.