If the butterfly valve is required to be used as flow control, the main thing is to correctly select the size and type of the valve. The structure principle of butterfly valve is particularly suitable for making large diameter valves. Butterfly valves are not only widely used in petroleum, gas, chemical, water treatment and other general industries, but also used in the cooling water system of thermal power stations.???

Classification and difference of metal conduit
The conduit is a device used to carry sporadic cables. The ordinary embedded device is in the wall or in the air. It serves as the threading channel from the bottom box of the user end to the bridge at the top of the room (or under the anti-static floor). It can also serve as the threading channel between the bottom box and the bottom box. The conduit can be divided into metal conduit and plastic conduit according to the data. The metal conduit is generally used in places where the grounding and shielding performance of the bearing equipment are required to be high. The specifications of threading pipes are usually divided by diameter, and the unit is mm, such as 16, 20, 25, 32, etc. Various threading pipes and their accessories are shown in the figure.
Various threading pipes and accessories
Common metal threading pipes can be divided into two categories according to material and process: K
G pipe and JDG pipe. K
G is a buckle type galvanized thin-walled wire tube. Its principle is to press the pipe and pipe fittings out of the pit with buckle pliers to achieve the purpose of tight connection; JDG is a tight set galvanized thin-walled wire tube, and its connection is completed by the pipe jacking screw. The differences between the two are mainly shown in the following three aspects.
1) Connection mode: K
G pipe is of buckle compression type, and JDG pipe is of fastening type.
2) Treatment for pipeline turning: K
Bend joints shall be used for G pipes, and benders shall be used for JDG pipes.
3) Pipe wall thickness: there are two types of JDG pipe thickness: ordinary type (1.2mm) and standard type (1.6mm); K
There are also two types of G pipe thickness: ordinary type (1. Omm) and standard type (1.2mm). The standard type is suitable for laying in the embedded and suspended ceiling, while the ordinary type is only suitable for laying in the suspended ceiling.