Knowledge of pneumatic valve gate

brake pneumatic valve knowledge
brake pneumatic valve is closed ( Disc along the pathway of the center line of the vertical direction of the pneumatic valve. Brake pneumatic valve in the pipeline are cut off. Brake pneumatic valve is a kind of pneumatic valve, use is very wide diameter DN of mm or cutting device are usually choose it, sometimes caliber brake pneumatic valve is used in the small cutting device also. A

the advantages of pneumatic valve, gate, small fluid resistance.
, open and close the required external force is small.
and the flow of medium is not restricted.
, wide open, the sealing surface erosion by working medium is smaller than by the pneumatic valve.
, is relatively simple, casting process is better.
2, the shortcomings of pneumatic valve gate
open height are larger, size and shape. Install the required space.
, opening and closing process, has the relative friction sealing surface, easy to cause scratches.
and brake pneumatic valve is generally has two sealing surface, adds some difficulties to machining, grinding and maintenance.
3
the kinds of pneumatic valve, gate, according to the structure of the disc can be divided into:
parallel brake pneumatic valve sealing surface parallel to the vertical centerline, the two brake pneumatic valve sealing surface parallel to each other. In parallel brake pneumatic valve, with thrust wedge structure for common, most often in both two gate with double side thrust wedge, the brake pneumatic valve is suitable for the low pressure of medium and small diameter ( DN— Mm brake pneumatic valve. A between the two gate there is spring, spring can be preloaded force, is advantageous to the disc sealing. Pneumatic wedge gate valve, sealing surface and vertical centerline into some sort of perspective, namely two pneumatic sealing surface into a wedge gate valves. Sealing surface Angle generally have a ° & acute; °,朴归隐者; , °, °, °, such as Angle mainly depends on the size of the medium temperature. Generally the higher the working temperature, from the point of view should be more big, to reduce the temperature change occurs when the possibility of a wedge. In the pneumatic wedge gate valve, and the single ram, double disc and flexible disc. Single ram air wedge gate valve, the structure is simple, the use of reliable, but for the sealing surface Angle of the accuracy is higher, the processing and maintenance more difficult, the temperature changes of wedge possibility is very large. Double ram pneumatic wedge gate valve is widely used in the water and steam pipe. Its advantages are: precision requirements for sealing surface Angle is low, the temperature change is not easy to cause the phenomenon of wedge, sealing surface wear, can add gasket compensation. But this kind of structure parts is more, easy bonding in viscous medium, and affect the sealing. More mainly upper and lower damper long-term use are prone to rust, ram is easy to fall off. Flexible disc pneumatic wedge gate valve, it has a single ram pneumatic wedge gate valve structure simple, the advantages of using can be *, and make up for the sealing surface Angle can produce trace amounts of elastic deformation occurring in the process of processing deviation, improve the manufacturability, is widely adopted now.
, according to the structure of the pneumatic valve rod brake can be divided into the
pneumatic valve stem brake pneumatic valve, pneumatic valve stem nut on the pneumatic valve cover or stents, open and close the damper, using rotating pneumatic stem nut to realize the rise and fall of pneumatic valve stem. This structure is good for pneumatic lubrication of the stem, the degree of opening and closing, so widely used.
non-rising stem brake pneumatic valve, pneumatic valve stem nut in pneumatic valve body, direct contact with the media. When open and close the damper using rotary pneumatic valve stem. The advantage of this structure is: the height of the pneumatic valve gate always remains the same, so the space is little, installation is suitable for large diameter or restricted the pneumatic brake valve installation space. With this kind of structure to open and close indicator, to indicate the degree of opening and closing. The disadvantage of this structure is: pneumatic valve stem threads without lubrication, and directly to medium erosion, easy to damage.
4, brake pneumatic valve size shrink if a pneumatic valve body is not the same as the channel diameter ( Tend to be pneumatic seat in size less than the size of the flange joint, called size shrinkage.
size shrinkage can make parts size shrink, the opening and closing force corresponding decreases, and at the same time can also enlarge the range of components. But after size shrinkage. Fluid resistance loss increased. Under the condition of some certain department ( Departments such as oil pipeline, are not allowed to use size shrinkage of pneumatic valve. This is in order to reduce pipeline resistance loss on the one hand, on the other hand is to avoid size shrinkage after create obstacles to mechanical cleaning the pipeline.