Application of electric butterfly valve in vibration equipment
At present, the application scope of electric butterfly valve is more and more extensive, especially in some vibration equipment, electric butterfly valve has become one of the indispensable equipment. Therefore, it is necessary to discuss the application of electric butterfly valve in vibration equipment, which is necessary to improve the application effect.
2、 Construction mode and characteristics of electric butterfly valve
The electric butterfly valve is an elastic element that uses the reaction force of compressed air inside the electric butterfly valve as the elastic restoring force. Electric butterfly valves are widely used in power machinery, electronic equipment, instrumentation, chemical machinery and other equipment in the fields of automobile, railway vehicles, ships, aviation, industry, etc. due to their good vibration reduction and isolation performance.
1. Construction mode of electric butterfly valve
The electric butterfly valve is a non-metallic butterfly valve that is filled with air with a certain pressure in the flexible bag and uses the compressibility of air to complete the elastic function. The electric butterfly valve is mainly divided into two categories: the capsule type electric butterfly valve and the membrane type electric butterfly valve.
In today's mechanical design process, electric butterfly valves, like gears, can be regarded as standard parts, and corresponding electric butterfly valves can be selected according to the weight of the load and the size of the geometric device.
2. Characteristics of electric butterfly valve
(1) The elastic coefficient of the electric butterfly valve is variable. As the load increases, the elastic coefficient also increases. The electric butterfly valve can design various characteristic curves to meet various performance requirements, because the electric butterfly valve has nonlinear characteristics.
(2) The body of the electric butterfly valve is relatively light, and the air quality is also very small. Most of the weight of the electric butterfly valve comes from the upper cover and the lower cover. Unlike the steel butterfly valve, the metal quality is relatively heavy.
(3) The bearing capacity of the electric butterfly valve can be adjusted according to the inflation pressure in the electric butterfly valve. For the same electric butterfly valve, the inflation pressure can be adjusted to meet different bearing capacity requirements.
(4) Since the electric butterfly valve uses air as the elastic medium, when compressed, the internal friction is small, so the vibration isolation characteristics are comparable. In addition, the electric butterfly valve has a good ability to eliminate noise, because the air and the ability to transmit sound are relatively weak.
(5) Electric butterfly valves are relatively strong in fatigue resistance. Experiments show that the acceptable number of stress cycles for ordinary steel plate butterfly valves is 500000 to 600000 times, while that for ordinary electric butterfly valves can reach about 3 million times, and that for high-performance electric butterfly valves can reach more than 5 million times. Therefore, the electric butterfly valve plays a prominent role in resisting strain.
(6) However, the manufacturing process of electric butterfly valve is demanding and complex, so the cost is high.
3、 Control system of electric butterfly valve
The control system of the electric butterfly valve has undergone two innovations with the progress of other related technologies, and experienced three development stages: mechanical control, electronic control and intelligent control. However, no matter what kind of control system, it generally includes three sub modules: air supply system (air source), control components (including software), and safe installation (to ensure the normal operation of electric butterfly valve). The air source and safe installation of the three control systems will be different with different control components, but their most basic difference is the control components. As for the mechanical control system, its control components are mainly height control valves, which can automatically stop the inflation and exhaust of the electric butterfly valve to complete the height control of the electric butterfly valve; The electronic control system is a qualitative leap forward compared with the mechanical control system. It uses the electronic controller (ECU) to collect the signals from various sensors, stop analyzing the signals, and send the control signals to the actuator (mainly various solenoid valves) to complete the control of the electric butterfly valve; The intelligent control system is developed on the basis of the electronic control system with the help of today's automatic control theory. It mainly improves the software of the ECU. It can not only control the height and rigidity of the electric butterfly valve, but also control the nonlinear characteristics of the electric butterfly valve by applying control technologies such as fuzzy neural network.
4、 Analysis of several influencing factors
The proportion of the volume of the air chamber and the additional air chamber, the shape, data and size of the electric butterfly valve, and the size of the orifice between the air chamber and the additional air chamber have a certain impact on the system stiffness and natural frequency.
1. The influence of the stiffness of the spring capsule data on the first order resonant frequency of the system. The experiment proves that the rigidity of the electric butterfly valve has a great influence on the rigidity of the electric butterfly valve, which is the reason why the theoretical value of the rigidity of the electric butterfly valve differs greatly from the experimental value. The greater the rigidity of the electric butterfly valve, the greater the rigidity of the electric butterfly valve, and the higher its first resonant frequency, which results in the improvement of the minimum operating frequency of the system. Therefore, the electric butterfly valve isolation system should reduce the data stiffness and natural vibration frequency, so that the minimum operating frequency of the system is as low as possible under the condition that the bearing capacity of the flawless butterfly valve isolator can have enough margin.
2. When the vibration table vibrates laterally, the stiffness of the spring capsule data is much greater. The body of the electric butterfly valve is soft, so it has comprehensive vibration isolation functions in axial, transverse and rotary directions. When the mechanical vibration table vibrates laterally, the spring capsule data stiffness is much larger.
3. An orifice is set between the electric butterfly valve and the additional air chamber. When air flows through the orifice, it will absorb a local vibration energy due to resistance, thus playing the role of vibration damping. In addition to affecting the stiffness and natural frequency of the system, the size of the orifice mainly affects the damping of the system.
The system stiffness decreases with the increase of the orifice opening, and the damping first increases and then decreases with the increase of the orifice. The increase of the volume of the additional air chamber can reduce the system stiffness and increase the damping ratio. The increase of the incentive frequency will increase the system stiffness and reduce the system damping ratio. The change of static load has little effect on the system vibration characteristics.