Flange connection is the most basic and common connection method in various vessels and process pipelines. Due to the requirements of the production process or the convenience of manufacturing, transportation, installation and maintenance, the connection between the container and the process pipeline is often a detachable structure, that is, flange connection, which has good connection strength and tightness, and is applicable to a wide range of sizes. Therefore, flange connection is widely used in vacuum salt-making enterprises. Since the medium in the container and pipeline is sodium chloride solution (ie brine), it has strong corrosiveness. Although carbon steel flanges have higher Strong safety and good plasticity and cutability. But the corrosion resistance is poor. Generally, a large area of corrosion will occur after one month of use. After six months, a large area of perforation will appear. Cause medium leakage. If stainless steel flanges are used: First, the price is more expensive. The stainless steel (ICr18Ni9Ti) flat flange is about 3-5 times that of the carbon steel flange; the second is that the welding technology is relatively more demanding. The third is that the stainless steel flange currently used will reduce the plasticity, toughness and stamping performance of the material due to the existence of titanium carbide in the steel. If it is not used properly, it will easily cause the flange to break.
Flange connection stainless steel valve, flange connection is that the valve body has flanges at both ends, corresponding to the flanges on the pipeline, and is installed in the pipeline by bolting the flanges. Flange connection is the most used connection form in stainless steel valves. Flanges are divided into convex surface (RF), flat surface (FF), convex and concave surface (MF), etc. According to the shape of the joint surface, it can be divided into the following types:
1) Smooth type: for stainless steel valves with low pressure. Processing is more convenient
2) Concave-convex type: high working pressure, medium and hard washers can be used
3) Tongue and groove type: gaskets with larger plastic deformation can be used, which are widely used in corrosive media and have better sealing effect.
4) Trapezoidal groove type: use an oval metal ring as a gasket, used for valves with a working pressure of ≥64 kg/cm², or high temperature valves.
5) Lens type: The gasket is in the shape of a lens and is made of metal. Used for high pressure valves with working pressure ≥100 kg/cm², or high temperature valves.
6) O-ring type: This is a newer form of flange connection, which is developed with the emergence of various rubber O-rings.