|
Problems in the application of pressure control valves1. Problems in the application of pressure control valves ① There are many varieties, specifications, and parameters of pressure control valves. Pressure control valves have nearly a thousand different specifications and types of products to meet the control requirements of different industrial production processes, such as temperature, pressure, medium characteristics, etc., making it inconvenient to select, install, maintain, and manage pressure control valves. ② The reliability of pressure control valves is poor. The characteristics of pressure control valves at the factory are significantly different from those after a period of operation, such as increased leakage, increased noise, and decreased valve reproducibility, which pose difficulties for long-term stable operation. ③ Pressure control valves are bulky and require transportation, installation, and maintenance Maintenance brings inconvenience. Usually, the weight of a control valve is several to hundreds of times heavier than that of a typical instrument. For example, a DN200 control valve weighs 700kg, and transportation, installation, and maintenance require the use of some mechanical equipment to complete, which brings inconvenience to the application of the control valve. ④ The flow characteristics of the pressure control valve do not match the characteristics of the industrial process controlled object, resulting in a deterioration of the quality of the control system. The ideal flow characteristics of pressure control valves have been determined at the time of product delivery, but the characteristics of the controlled objects in industrial processes vary, and the pressure drop ratio on the force port changes, which makes the working flow characteristics of the control valve unable to match the characteristics of the controlled objects and deteriorates the control quality of the control system. ⑤ The pressure control valve has excessive noise. In industrial applications, control valve noise has become the main source of noise in industrial equipment. Therefore, reducing control valve noise has become an important research topic and has received attention from governments around the world. ⑥ Pressure control valves are energy consuming equipment. In the current situation where energy is becoming increasingly scarce, energy-saving technologies should be adopted to reduce the energy consumption of control valves and improve energy utilization efficiency. 2. Development direction of pressure control valves The development direction of pressure control valves mainly includes intelligence, standardization, miniaturization, rotation, and safety. (1) Intelligence and standardization The intelligence and standardization of control valves have been put on the agenda. Intelligence mainly adopts intelligent valve positioners. Intelligence is manifested in the following aspects. ① The intelligent functions such as self diagnosis of control valves and remote communication of operating status make the management of control valves convenient, fault diagnosis easy, and also reduce the skill requirements for maintenance personnel. ② Reduce product types and simplify production processes. The use of intelligent valve positioners can not only conveniently change the flow characteristics of the control valve, but also improve the control quality of the control system. Therefore, for the control valve flow rate The requirements for sex can be simplified and standardized (for example, only producing linear characteristic control valves). Intelligent functional modules can be used to match the characteristics of the controlled object, greatly reducing the types and varieties of control valve products, and making control valves more versatile The manufacturing process has been simplified and has been tested and recognized in production and the market. ③ Digital communication. Digital communication will be widely used in control valves. Based on the HART communication protocol, some valve positioners of control valves will implement input signals and valve position signals on the same transmission line; with Based on fieldbus technology, the combination of control valves, valve positioners, and PID control function modules enables control functions to be implemented at the field level, dispersing hazards and making control more timely and rapid. ④ Intelligent valve positioner. The intelligent valve positioner has all the functions of a valve positioner, while also improving the dynamic and static characteristics of the control valve and enhancing the control accuracy of the pressure control valve. Therefore, it is intelligent Valve positioners will become important auxiliary equipment for control valves and be widely used in the near future. |
