Connection mode of instrument valve
1、 Flange connection form of instrument valve.
The flange connection of instrument valve is the connection with flange at both ends of the valve body, which is corresponding to the flange on the pipeline, and the flange is fixed on the pipeline with bolts. Flange connection of instrument valve is the most commonly used connection form in valves. The process is relatively simple; concave convex type: high working pressure, can use medium hard washer; tenon groove type: can use plastic large deformation washer, widely used in corrosive medium, sealing effect is good; trapezoidal groove type: use elliptical metal ring as gasket, valve or instrument valve, working pressure ≥ 64kg / cm2; lens type: washer is lens shape, made of metal. It is suitable for high pressure valve, working pressure ≥ 100kg / cm2. It is a new flange connection form. It is developed with the appearance of various rubber rings and instrument valves, and its sealing effect is more reliable than ordinary flat washer.
2、 Type of clamp connection for instrument valves.
The valve is installed in the middle of two flanges. There are usually positioning holes on the valve body to facilitate installation and positioning. The valve and the two flanges are directly connected by bolts.
3、 Type of welded connection for instrument valves.
Butt welding connection: the two ends of the valve body are processed into corresponding groove corresponding to the butt welding of the pipeline weld according to the requirements of butt welding, and the groove is fixed with the weld.
Socket welding connection: both ends of valve body are treated as socket connection, and connected with pipeline through socket welding.
4、 Instrument valve threaded connection type.
Thread connection is a simple way of connection, which is often used in small valves. According to the specification of thread, the valve body has internal thread and external thread. Corresponding to the thread on the pipe.
There are two types of threaded joints:
Direct sealing: internal and external threads directly play a sealing role. In order to ensure no leakage, lead oil, thread hemp and polytetrafluoroethylene (PTFE) raw material are used for filling. Polytetrafluoroethylene (PTFE) raw material belt is very common in use, with long service life, good corrosion resistance, easy to seal, easy to use and save. It can be taken out completely when disassembled, because it is a non viscous film, far better than lead oil and thread hemp.
Indirect seal: the force of screw thread is transmitted to the washer between two planes to seal. There are five kinds of common thread: metric common thread; British common thread; sealed pipe thread; unsealed pipe thread; American Standard pipe thread.
