Working principle of butterfly valve.
The butterfly valve is a kind of valve that uses the disc type opening and closing parts to rotate about 90° to open, close or adjust the medium flow.
Butterfly valve is not only simple structure, small size, light weight, material consumption, small installation size, small driving torque, simple and rapid operation, and can also have good flow regulation function and close sealing characteristics, is one of the fastest developing valve varieties in recent decades. Butterfly valves are widely used. The variety and number of its use is still continuing to expand, and to high temperature, high pressure, large caliber, high sealing, long life, excellent regulating characteristics, as well as a valve multi-function development. Its reliability and other performance indicators have reached a high level.
With the application of chemical resistant synthetic rubber in butterfly valve, butterfly valve performance can be improved. Because the synthetic rubber has corrosion resistance, erosion resistance, size stability, good resilience, easy to form, low cost and other characteristics, and can be selected according to different use requirements of different properties of synthetic rubber, in order to meet the use of butterfly valve working conditions.
Because polytetrafluoroethylene (PTFE) has strong corrosion resistance, stable performance, not easy to aging, low friction coefficient, easy to form, size stability, and can be filled, add appropriate materials to improve its comprehensive performance, get better strength, lower friction coefficient butterfly valve sealing material, overcome the limitations of synthetic rubber, Therefore, polytetrafluoroethylene as the representative of polymer polymer materials and its filling modified materials, in the butterfly valve has been widely used, so that the performance of the butterfly valve has been further improved, the production of a wider range of temperature, pressure, reliable sealing performance, longer service life butterfly valve.
In order to meet the requirements of high and low temperature, strong erosion, long life and other industrial applications, the metal sealed butterfly valve has been greatly developed. With the application of high temperature resistance, low temperature resistance, strong corrosion resistance, strong erosion resistance, high strength alloy materials in the butterfly valve, the metal seal butterfly valve in high and low temperature, strong erosion, long life and other industrial fields have been widely used, the emergence of large diameter (9~750mm), high pressure (42.0MPa), wide temperature range (-196~606℃) butterfly valve, So that the butterfly valve technology to a new level.
The butterfly valve has small flow resistance when it is fully opened. When opened between about 15°~70°, and can carry out sensitive flow control, so in the field of large diameter adjustment, butterfly valve application is very common.
Most butterfly valves can be used in media with suspended solid particles due to the movement of the butterfly plate with wipeability. Depending on the strength of the seal, it can also be used for powder and granular media.
Butterfly valve is suitable for flow regulation. Because the butterfly valve in the pipe pressure loss is relatively large, about three times the gate valve, so in the selection of butterfly valve, should fully consider the pipeline system affected by the pressure loss, should also consider the closure of the butterfly plate under the pipeline medium pressure strength. In addition, the limitations of the operating temperature that the elastic seat material can withstand at high temperatures must be considered.
The structure length and overall height of the butterfly valve is small, opening and closing speed is fast, and has good fluid control characteristics. The structure principle of butterfly valve is most suitable for the production of large diameter valves. When the butterfly valve is required to be used for flow control, the most important thing is to correctly select the size and type of the butterfly valve, so that it can work properly and effectively.
Usually, in the throttling, adjusting control and mud medium, the structure is required to be short, fast opening and closing speed, low pressure cut-off (small pressure difference), the recommended choice of butterfly valve. The butterfly valve can be selected in the double position adjustment, reduced diameter channel, low noise, cavitation and vaporization phenomenon, a small amount of leakage to the atmosphere, with abrasive medium. Throttle adjustment under special working conditions, or require strict sealing, serious wear, low temperature (deep cooling) and other working conditions.
