Analysis on the causes of vibration of pneumatic control valve and Its Solutions

Analysis on the causes of vibration of pneumatic control valve and Its Solutions

Analysis on the causes of vibration of pneumatic control valve and Its Solutions

The vibration of pneumatic control valve is generally divided into two states. One is the overall vibration of pneumatic control valve, that is, the whole pneumatic control valve vibrates frequently on the pipeline or base. The other is the vibration of the regulating valve core, which can be seen from the frequent movement of the valve stem up and down. The causes of these two kinds of vibration and their treatment measures are analyzed as follows:

The vibration causes of the whole pneumatic control valve on the pipeline are roughly as follows: the violent vibration of the pipeline or base is easy to cause the vibration of the whole pneumatic control valve; In addition, it is also related to frequency, that is, when the external frequency is equal to or close to the natural frequency of the system, the energy of forced vibration reaches a large value and produces resonance. These two factors sometimes affect each other, which will make the vibration more and more intense, make the pipeline jump, loose accessories or components, and make a clatter sound. In serious cases, it will also cause the valve stem to break and the valve seat to fall off, resulting in the failure of the system. Based on this situation, each pipe and base causing vibration shall be reinforced, which also helps to eliminate the interference of external frequencies.

The installation position of pneumatic control valve shall be far away from the vibration source. If it is inevitable, preventive measures shall be taken. When the vibration of the whole pneumatic control valve has not reached resonance, the pneumatic control valve can basically adjust with the external given signal. Because the relative displacement of the external given signal to the valve core does not change or change very little due to the vibration of the whole pneumatic control valve, the reason is that they are a whole. The sharp opening or closing of the stop valves at both ends of the pneumatic control valve will make the rapidly flowing wave measuring medium produce a strong reflected shock wave, which will shock the regulating valve core.

The output of the positioner fluctuates due to the fluctuation of the air source, or the movable part of the positioner is rusted and inflexible, so that the input and output signals do not correspond, resulting in jumping oscillation. At this time, open the cleaning positioner of the air supply pressure reducing valve and apply lubricating oil to the movable part to eliminate the friction force. As a result of the unbalanced force of the pneumatic regulating valve itself, the regulating valve core often oscillates. If the jacking force of the zero point spring is too small, the ability to resist external interference is small. When the external signal is small, the valve core is easy to vibrate.