Advanced modern industry is marked by production automation. From the development history and progress of automation system, the change of technical tools plays an extremely important role. Various kinds of advanced control methods are constantly emerging, but the basic rules of control have not changed. The improvement of technical tools is changing with each passing day. The development and use of intelligent instruments more for industrial automation to create a better future. Typical automation control system has three main parts: detection, control, the implementation of three parts. In recent years, testing instrumentation and control instrumentation by digital technology and microprocessor technology changes occur for a moment to see, and this part of the actuator, especially as the main product of the control valve, but also great progress. Traditionally used control valve basically meet the needs of many industrial systems, but with the large-scale development of modern industry. How to produce more and better advanced products, how to improve product quality standards, how to operate more effectively and safer, how to make full use of resources, save energy and protect the ecological environment, people recall that the regulating valve put forward higher requirements , These requirements can be summarized as follows: (1) more stable quality, work more reliable, safer operation In the process control, the control valve directly in contact with the fluid, in the event of failure, the consequences could be disastrous. In the oil industry, from oilfields to oil refineries, all kinds of production facilities are centrally monitored and controlled on a large scale. Most of the operating conditions are carried out under high temperature and low pressure or high temperature and pressure. The mediums are all flammable and explosive oils All kinds of oil, therefore, the reliability and fire control valve was mentioned in the first place. In the chemical industry, the process of diversity and process conditions change, the temperature, pressure, flow and level of the four major thermal variables in the control and implementation, there are very special problems require regulatory valve can be applied. In the power industry, the thermal power plant to control the boiler, boiler control system to maintain the normal water level is crucial to avoid misoperation of the control valve, double what is important. In order to ensure the working performance and reliability of the control valve, the following requirements must be met: 1. To ensure the quality of the control valve. The selection of the control valve is subject to rigorous calculation; the type, caliber and various properties shall meet the requirements; Parts of the material to be rigorously selected, to have sufficient strength and stiffness, in accordance with national standards through the pressure test, tightness and other tests. Manufacturers of manufacturing technology and testing methods must meet the standards, to be recognized by the competent authorities. It is strictly forbidden to produce small factories that do not have the production conditions. 2, to ensure reliable operability Here does not mean that the quality of the valve manufacturing itself, but also to the training of operators and improve the quality. In order to prevent misuse, process personnel must pay attention to the nameplate marked the precautions. According to our new pneumatic control valve standard (GB / T4213-92) pneumatic actuator nameplate at least indicate the manufacturer name, product type, rated flow coefficient, design number, product number and manufacturing date and other matters. The body should be cast or punched out of the media flow direction of the arrow and DN values ​​and PN words and values. Important valve must have enough accessories, such as locators, limit switches. Have enough installation space and operating space, adequate installation space and operation, adequate lighting, strict operating procedures. 3, emergency device When the high-pressure gas equipment failure, in order to prevent direct damage to other equipment, must be installed in the pipeline connecting equipment cut off, if necessary, install quick shut-off valve. The rapid cut-off valve leakage to have strict rules. In the case of easy to sweep the fire, from the structural considerations to the valve fire resistance, or fire-retardant coating approach. The emergency device has a fireproof bag which can be put in a few minutes. The material of the bag contains a plurality of layers of ceramic fibers or glass fibers. A connecting rod protection method is also available. The clamping elements can be made of some fusible connecting rod, Electric connecting rod, these links start when the heat, when the fire is off, so that the valve moved to a safe location. (2) Protecting the environment The importance and necessity of protecting the natural environment and the living environment are well known. Regulating valve on the environment pollution is mainly air pollution and noise and other issues. 1, in order to prevent air pollution, valve sealing parts can not be leaked. Pay attention to the sealing method and sealing material selection. When the fluid is toxic, such as chlorine or CO and other media, we must consider the bellows seal or a more reliable method of sealing. In order to prevent the more terrible leakage of radiation fluid, but also to comply with the requirements and regulations of the use of nuclear power plants, using a special method. 2, to prevent noise In the control valve on the issue of environmental protection, the noise problem is very prominent. The types of control valve noise are mechanical noise, hydrodynamic noise, aerodynamic noise, the mechanisms by which they are generated, their prediction and prevention, as discussed in detail in Chapter 5. (3) energy conservation In the process of using the adjustment to the energy-saving issues and control valve structure, use, installation, maintenance linked. 1, the use of low-impedance valves to minimize the fluid flow valve kettle impedance, reduce energy consumption. When using the ball valve, under the full opening of the core hole and the pipe diameter if the same, you can save compressor, pump and other equipment power consumption. Compared with some traditional valves. Cam deflection valve has a larger capacity, the same pressure can be adjusted for the same flow, to reduce energy consumption purposes. The use of some valve trim changes in the structure of the valve, such as the use of low-S valve, can achieve the purpose of saving energy. 2, to improve the valve core, seat sealing performance Valve core seat seal is not good, the valve can not be completely closed, leakage caused by the pressure drop caused by loss of power. In order to improve the sealing energy, can be used with glass fiber-doped PTFE or graphite instead of pure PTFE valve seat, the use of high hardness gaskets, the use of labyrinth sealing surface and other methods, but also to protect the seal Face can not be damaged. 3, try to adopt the electric actuator using pneumatic actuator to maintain a certain pressure to move, so a lot of energy consumed by the year, such as electric actuator, just to change the opening when the power supply, when the valve reaches the desired opening Stop the power supply. (4) Suitable for new energy For a long time, petroleum is a major energy source. In recent years, many new energy sources have come up with more special requirements on control valves, from processing to production to transportation and storage. Liquefied natural gas is a clean energy source, but due to the fluid temperature of the liquefied natural gas plant being as low as minus 162 degrees centigrade, liquefied natural gas has new requirements for the regulating valve and the materials and structures used therein. The key is to solve the material strength, brittleness and deformation problems, and requires the action part can not be frozen. Cryogenic valves require a special approach from structure to material handling if they are used in cryogenic space vehicle liquid hydrogen (negative 253 degrees Celsius) and liquid helium (negative 269 degrees Celsius). 2, liquefied coal slurry Pulverized coal and flux mixed, and then after a series of treatment and desulfurization, get a high quality fuel --- liquefied coal slurry. The spinning valve used in this system is subject to high-speed erosion of coal slurry, which will be abraded and damaged quickly. The hardness, wear resistance, heat resistance and toughness of the material are very important. , In addition to the selection of suitable materials, but also can be segmented or labyrinth structure to ease the scouring effect of coal slurry. 3, atomic power station automatic control system must use the control valve. Control of superconducting low temperature liquid hydrogen in the process of nuclear polymerization, this control valve must meet the following requirements: a, with a structure to prevent the leakage of radioactive material; b, excellent performance; c, adjustment, easy maintenance; d, Materials can withstand radioactivity; e, can not use taboo substances (such as chlorine and other halogen materials). Can be seen, compared with the common control valve, the control valve design, manufacture, testing, inspection and use of more special and more stringent, in order to ensure safety, must be given from all aspects. Looking forward, we should face more problems: the demand for raw materials falls short of demand; the consumption and lack of oil, coal and water resources; the demand of society for improving productivity and working conditions; and the calls for environmental protection and improving the quality of human life. To solve these problems, the old process control system should be improved, or to create a new process control method, and the new system on the regulatory valve requirements even higher.