Single Acting AC Hydraulic Power Unit Single Acting Ac Hydraulic Power Unit,Ac Single-Acting Hydraulic Power Pack,Ac Single-Acting Hydraulic Power Pump,Ac Single-Acting Hydraulic Power Station Huaian Yansheng Hydraulic Machinery Co., Ltd. , https://www.yshydraulics.com
Abstract: The composition and classification of control valve, selection principle and method of adjustment type, actuator, mode of action, flow characteristics and so on are mainly expounded. And the methods and principles of adjusting Yan selection are analyzed. Analysis of the role of the control valve in the process control is to accept the control signal of the regulator or the computer to change the flow of the medium to be adjusted so as to maintain the parameter to be adjusted within the required range , So as to achieve the automation of the production process. If the automatic adjustment system compared with the manual adjustment process, the detection unit is the human eye, the control unit is the human brain regulation, then the execution unit is the human hand and foot, the control valve is the human hand and foot. To achieve a process parameters such as temperature, pressure, flow, level and other regulatory control, are inseparable from the control valve. Therefore, the correct choice of control valve in the process of automation of great significance. 1 control valve composition and classification Regulating valve, also known as control valve, is the main type of actuator, by receiving the control signal output of the control unit, with the power to change the fluid flow. Regulating valve generally by the implementing agencies and valves. If you press the actuator used by its power, the control valve can be divided into pneumatic, electric, hydraulic three, that is, compressed air as the power source of the pneumatic control valve, electric power to the electric control valve to liquid medium (Such as oil) pressure-powered electro-hydraulic control valve, in addition, according to their functions and characteristics of points, as well as solenoid valve, electronic, intelligent, field bus type regulating valve. Control valve of many types of products, the structure is also diverse, but also constantly updated and changing. Generally speaking, the valve is universal, it can be matched with the pneumatic actuator, but also with the electric actuator or other actuator. 2 control valve type selection 2.1 valve body type selection valve body selection is the most important part of the control valve selection. There are many types of regulating valve body, commonly used through a single seat, through two-seater, angular, diaphragm, small flow, tee, eccentric rotation, butterfly, sleeve, spherical and other 10 species. Before selecting a valve, carefully analyze the medium, process conditions, and parameters of the control process, collect enough data to understand the system requirements for the regulator, and determine the type of valve to be used based on the data collected. In the specific choice, the following aspects can be considered: (1) spool shape and structure based on the selected flow characteristics and unbalanced forces and other factors to consider. (2) Wear resistance When the fluid medium is a suspension containing high concentration of abrasive particles, the valve core, the valve seat joint surface will be severely rubbed each time it is closed. Therefore, the flow of the valve should be smooth, the valve's internal material to be hard. (3) Corrosion resistance Due to the corrosive medium, try to choose a simple structure of the valve in the case of regulatory function. (4) Medium temperature, pressure When the medium temperature, high pressure and changes, should use the valve core and valve seat material by temperature, pressure changes in small valves. (5) to prevent flash and cavitation flash and cavitation only produce liquid medium. In the actual production process, flash and cavitation not only affect the calculation of flow coefficient, but also the formation of vibration and noise, so that the valve life is shorter, so the valve should be selected to prevent flash and cavitation. 2.2 Control Valve Actuator Selection 2.2.1 Output Force Considerations Regardless of the type of actuator, its output force is used to overcome the effective load (mainly refers to unbalanced and unbalanced torque plus friction, Sealing force, gravity and other related forces). Therefore, in order for the regulating valve to work normally, the matched actuator should be able to generate enough output force to overcome various resistances and ensure a high degree of sealing and valve opening. For double-acting pneumatic, hydraulic, electric actuator, there is usually no return spring. The size of the force has nothing to do with its direction of operation, so the key to choosing an actuator lies in knowing the maximum output force and the torque of the motor. For single-acting pneumatic actuators, the output force is related to the opening of the valve, and the presence of force on the regulating valve will also affect the kinematic behavior, thus requiring a force balance across the opening of the regulating valve.