Requirements for the use of regulating valves in modern industry
Advanced modern industry is marked by production automation. From the perspective of the development history and progress of automation systems, changes in technical tools play an extremely important role. Various advanced control methods are constantly emerging, but the basic control laws have not changed, while the improvement of technical tools is changing with each passing day. The development and use of smart meters is a brighter future for industrial automation. A typical automation control system mainly consists of three parts: detection, control, and execution. In recent years, it is obvious to all that the detection instruments and control instruments are influenced by digital technology and microprocessor technology, and the actuator, especially the control valve as the main product, has also made great progress. Traditionally used control valves 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 efficiently and safely, how to make full use of resources, save energy and protect the ecological environment, people recall that they have put forward higher requirements for regulating valves , These requirements can be summarized as follows: more stable quality, more reliable work, safer operation. In process control, once the regulating valve is in direct contact with the fluid, the consequences will be disastrous.
In the petroleum industry, from oil fields to refineries, various production units are 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 high pressure. Various oil products, therefore, the reliability and fire resistance of the regulating valve are mentioned in the first place. In the chemical industry, there are special problems in the control and implementation of the four major thermal variables of temperature, pressure, flow rate and liquid level due to the diversity of processes and changes in process conditions that require control valves to be applicable.
In the electric power industry, thermal power plants need to control the boiler. It is very important to keep the water level normal in the boiler regulation system, and to avoid the wrong opening and closing of the regulating valve. How important is it? In order to ensure the working performance and reliability of the regulating valve, the following requirements are met:
1. Ensure the quality of the control valve. The selection of the control valve must be strictly calculated; the type, diameter, and various properties must meet the requirements; the materials of various parts of the control valve must be strictly selected, and there must be sufficient strength and rigidity. The standard passes the pressure test, air tightness and other tests. The manufacturer's manufacturing technology and testing methods conform to the standards and must be signed and approved by the competent authority. Small factories that do not have production conditions are strictly prohibited from producing.
2. Ensuring reliable operability The injustice here refers to the manufacturing quality of the control valve itself, but also includes the training and quality improvement of operators. In order to prevent misoperation, the staff must pay attention to the precautions marked on the nameplate. According to my country's new pneumatic control valve standard (GB/T4213-92), the nameplate of the pneumatic actuator should at least indicate the manufacturer's name, product model, rated flow coefficient, design number, product number, and manufacturing year and month. On the valve body, the arrow indicating the flow direction of the medium and the value of DN and the words and values of PN should be cast or punched out. Important valves must have sufficient accessories, such as positioners, limit switches, etc. There should be enough installation space and operation space, enough installation space and operation, enough lighting, and strict operation rules.