Do you want to know the knowledge by the pneumatic valve are all here!

as pneumatic valve opening and closing is plug piece of pneumatic valve, sealing surfaces appear flat or cone, pneumatic disc make linear movement along the centerline of the fluid. Pneumatic valve stem form of exercise, lifting lever ( Pneumatic valve rod and hand wheel lifting) And lift rotating lever ( The handwheel with pneumatic valve rod rotating lifting, nut is located in the pneumatic valve) 。 By pneumatic valve used throughout opened only close, not allowed to adjust and throttling.
by the pneumatic valve belong to mandatory sealed pneumatic valve, in pneumatic valve is closed, so must to pressure pneumatic disc, to force a sealing surface does not leak. When medium by pneumatic disc below 6 into the pneumatic valve, operating force required to overcome resistance, pneumatic stem and packing of the friction force is produced by medium pressure and thrust, close the pneumatic valve force than the pneumatic valves open force is big, so the larger the diameter of the pneumatic valve stem, or pneumatic stem top bending failure happens. In recent years, from the seal of the pneumatic valve, the flow direction of medium by the pneumatic valve is replaced by air above the disc into the pneumatic valve cavity, in the medium pressure at this moment, close the pneumatic valve is small, the force and the great strength of pneumatic valve, pneumatic valve stem diameter can be reduced accordingly. At the same time, in the role of media, this kind of pneumatic valve is tight.

as the pneumatic valve opens, the opening of pneumatic disc height, for the nominal diameter % ~ %, traffic has reached maximum, said the pneumatic valve to full open position. So by the pneumatic valve fully open position, should be determined by pneumatic disc trip.
as of pneumatic valve has the following advantages:

, simple structure, manufacture and maintenance more convenient.
, small work schedule, opening and closing time is short.
, good sealing, small friction between the sealing surface, long service life.
as the shortcoming of pneumatic valve is as follows:

and fluid resistance is big, opening and closing the required force is larger.
, does not apply to take larger particles, viscosity, easy to coking of the medium.
and poor regulation performance.
as the kinds of pneumatic valve:

as the types of pneumatic valve according to the location of the pneumatic valve stem threads with external thread type, internal thread type. According to the flow of medium, have straight-through type, straight and Angle. By the pneumatic valve points, the form of the seal packing seal by the pneumatic valve and pneumatic valve bellows seal globe.
as the structure of pneumatic valve pneumatic valve body:

as the structure of pneumatic valve pneumatic valve body has a straight-through, straight and right Angle type. Straight-through are the most common type of structure, but the maximum resistance of the fluid. Once-through fluid resistance small, usually for containing solids or the viscosity of fluid. Right Angle type pneumatic valve forged, more suitable for smaller drift diameter, high pressure by the pneumatic valve.
as pneumatic valve installation and maintenance should be paid attention to the following:

, hand wheel, lever operation by the pneumatic valve can be installed in any position.
, hand wheel, lever and wei mechanism, does not allow for lifting.
and the flow of medium should be consistent with the direction arrow shown in pneumatic valve body.
as of pneumatic valve has the following advantages:

, in the process of opening and closing small pneumatic valve sealing surface friction than gate, wear-resisting.
, small opening.
, usually only one seal face, good manufacturing process, easy to repair
as many different kinds of pneumatic valve, pneumatic valve stem according to the position of the screw thread can be divided into:

. Thread on the pneumatic valve rod by pneumatic valve
as pneumatic valve pneumatic valve stem thread outside the pneumatic valve body. Its advantage is pneumatic valve stem from medium erosion, easy and smooth, this kind of structure is more common.
. Thread under pneumatic pneumatic valve stem as
as pneumatic valve pneumatic valve stem thread in pneumatic valve body. The structure of pneumatic valve stem thread direct contact with the media, are susceptible to erosion, and lubrication. This structure is used for small diameter and temperature is not high.
according to the channel direction of the stop pneumatic valve, can divide again; Straight through by the pneumatic valve, Angle type by the pneumatic valve and three-pass by pneumatic valve, both by the pneumatic valve is usually done after the flow direction of medium change and distribution of media use.