Law of pneumatic butterfly valve
According to this law, when the additional force gradually increases from zero and the sum of internal pressure PL × S is exactly the spring preload, the valve will slightly open, and the medium working area S will increase to the spring preload. The force increases exponentially, resulting in an immediate reduction of the additional external force. Therefore, the characteristic peak A appears. When the external additional force gradually decreases and reaches the closing point due to the rapid reduction of the medium working range, the external additional force immediately increases at that point to maintain force balance, which is the second feature.
It becomes the peak point B. The above two characteristic peaks A and B are the basis for detecting the opening and return pressure of the pneumatic butterfly valve in the online state. Pneumatic butterfly valves can be divided into vertical type, lever type, spring type and pilot type (pulse type) according to the structure. According to the structure of valve body, it can be divided into closed type and non closed type. The fact that the pneumatic butterfly valve is closed means that the discharged medium will not leak, and everything will be discharged along the outlet.
Usually used for corrosive and corrosive media. Closed pneumatic butterfly valve is mainly used for air and steam pneumatic butterfly valve. The selection of pneumatic butterfly valve products shall be determined according to the actual sealing pressure. The spring of the spring loaded pneumatic butterfly valve has multiple working pressure levels within the rated pressure (PN) range. When ordering, in addition to the type, name, medium and temperature of the pneumatic butterfly valve, the sealing pressure of the valve body must also be indicated.
