According to connection method classification ( 1) threaded connection valves: valve with internal thread or external thread, and pipe thread connection. 按连接方法分类(1)螺纹连接阀门:阀体带有内螺纹或外螺纹,与管道螺纹连接。
Component parts with bore such as pin valve, internal thread, oil pipe take up a large proportion in the oil industry, chemical industry and modern manufacturing industry. 孔类零件如针阀体、内螺纹、油管等在石油、化工和现代制造业中占有相当大的比重。