Shandong PPH Coated Flange Machining, PPH Coated Flange Price, PPH Coated Flange Sales. PPH pipe flange, also known as PPH pipe flange disk or boss, is a component that connects pipes with pipes and valves, fitting at the pipe ends. The PPH flange has holes, and bolts are used to tightly secure two PPH flanges. PPH flanges are sealed with gaskets. They come in threaded (screwed) PPH flanges,焊接 PPH flanges, and ferrule PPH flanges. They can be categorized by the connected parts as container PPH flanges and pipe PPH flanges; and by structural type, as integral PPH flanges, loose-fitting PPH flanges, and threaded PPH flanges. Common integral PPH flanges include flat welding PPH flanges and socket welding PPH flanges. Flat welding PPH flanges have lower rigidity and are suitable for pressure p≤4MPa; socket welding PPH flanges, also known as high-neck PPH flanges, have greater rigidity and are suitable for high-pressure and high-temperature conditions. The sealing surfaces of PPH flanges come in three types: flat sealing surface, suitable for low-pressure, non-toxic media conditions; concave-convex sealing surface, suitable for slightly higher pressure conditions; and tongue-and-groove sealing surface, suitable for flammable, explosive, toxic media, and high-pressure conditions.