Classification of pipe fitting union

　　The pipe fitting union is a general term for the connector that can be installed and disassembled in the fluid path. Commonly used pipe fitting union can be divided into two types: hard pipe fitting union and hose pipe fitting union. According to the connection mode of pipe fitting union and pipe, there are three types of hard pipe fitting union: welding type, ferrule type and flared type. The hose pipe fitting union is mainly the buckle type rubber pipe fitting union, which is often called quick pipe fitting union. Stainless steel and carbon steel are commonly used.

　　The thread standards include American, British and metric NPT, which are 60 degree taper pipe threads of American standards, and are used in North America. The national standard can be found in GB / t12716-1991pt, which is 55 degree sealed taper pipe thread, belonging to the Wyeth thread family, mostly used in European and Commonwealth countries. It is commonly used in water and gas pipe industry, with the taper specified as 1:16. The national standard can be found in GB / t7306-2000g, which is 55 degree non thread sealed pipe Thread, belonging to the Wyeth thread family, is marked as g for cylindrical thread. The national standard can refer to GB / t7307-200 welded pipe fitting union, which is welded by connecting pipe and pipe.

　　The end face of the O-ring seal is used between the connector body and the connecting pipe. It is simple in structure, easy to manufacture, good in sealing and low in size accuracy.