Threaded valve generally refers to the valve with internal thread or external thread on the valve body. It is mainly divided into internal thread valve and external thread valve. The connection mode of thread is corresponding to the pipeline.Threaded valves can only be manufactured with small diameter, and are used in normal or low pressure projects,for example, it can not be used in high pressure work, so it is necessary to connect the valve by welding or to connect the valve by flange.The common threaded valves include: threaded gate valve, threaded ball valve, threaded globe valve and threaded check valve.

The differences between internal thread valve and external thread valve:

From the use: because of the price, work flow needs, the market is mostly using internal thread valve.

From the channel: considering the connection of the thread, the diameter of the external thread of the same caliber is smaller than that of the internal thread, the flow rate is fast and the flow rate is small.

From the appearance: the pattern of internal thread is mostly pipe thread, the external thread is mostly taper thread, and the ferrule type external thread is pipe thread.

From the pressure resistance:The valve wall of the external thread of the same material is usually thicker than that of the internal thread (the smaller the passage, the thicker the wall),and the pressure resistance is greater.

The sealing form of threaded valve:

1.Direct sealing: the internal and external threads directly play a sealing role.In order to ensure that the joints do not leak, they are often filled with lead oil, twine and PTFE thread seal tape;Among them,PTFE thread seal tape is widely used;This material has excellent corrosion resistance, excellent sealing effect, and is easy to use and keep,when disassembling, it can be completely removed, because it is a non sticky film, which is much better than lead oil and hemp.

2.Indirect sealing: The force of screw tightening is transferred to the gasket between the two planes,allowing the gasket to play a sealing role.