Description: At present, domestic control valves are basically intelligent, standardized, fine and small, rotary transformation, integration and safety.
First, the intelligent control valve:
The intellectualization and standardization of control valves have been mentioned on the agenda. Intelligent mainly uses intelligent valve positioner. Intelligence is manifested in the following aspects.
1, the self-diagnosis of the control valve, the remote communication of the operating state and other intelligent functions, so that the management of the control valve is convenient, fault diagnosis is easy, but also reduce the skill requirements for maintenance personnel.
2. Reduce product types and simplify production processes. The use of intelligent valve positioner can not only easily change the flow characteristics of the control valve, but also improve the control quality of the control system. As a result, the requirements for control valve flow characteristics can be simplified and standardized (for example, only linear control valves are produced). The intelligent function module is used to match the characteristics of the controlled object, so that the types and varieties of the control valve products are greatly reduced, and the manufacturing process of the control valve is simplified.
3. Digital communication. Digital communication will be widely used in control valves, based on HA and the control field. Based on fieldbus technology, the valve positioner of the control and control valve realizes the input signal and the valve position signal in the same transmission line realization level, so that the danger is dispersed, and the control and control function is combined with the valve positioner and PID control function module in the field to make the system more timely and quickly.
4, intelligent valve positioner. Intelligent valve positioner has all the functions of the valve positioner, at the same time, can change the dynamic and static characteristics of the control valve, improve the control accuracy between the control, therefore, intelligent valve positioner in the next period of time will become an important control valve auxiliary equipment is widely used.
Second, the standardization of control valves is manifested in the following aspects.
1, in order to achieve interchangeability, control valves produced by different manufacturers of the same size and specifications can be exchanged, so that users do not have to spend a lot of time to choose a manufacturer.
2, in order to achieve interoperability, the control valves produced by different manufacturers should be able to work together with the products of other manufacturers, and there will be no signal mismatch or impedance mismatch.
3, standardized diagnostic software and other auxiliary software, so that different manufacturers of control valves can use standardized diagnostic software for operating status diagnosis, operating data analysis, etc. Standardized selection procedures. Control valve selection is still a matter of great concern to automatic control designers, the use of standardized calculation procedures, according to the data provided by the process, can correctly calculate the flow coefficient of the required control valve, determine the piping and select the appropriate valve body, spool and valve interior materials, so that the design process standardization, improve the design quality.
Three, the control valve miniaturization:
In order to reduce the weight of the control valve and facilitate transportation, installation and maintenance, the following measures are adopted to minimize the control valve.
1, the use of fine small actuator. Use lightweight materials; Multiple sets of springs are used to replace a set of springs to reduce the height of the actuator. In general, the control valve composed of a small pneumatic film actuator is more controlled than that composed of a pneumatic film actuator of the same type
2. Change the flow path structure. For example, change the movement of the spool to the movement of the seat, change the linear displacement to the angular displacement, etc., so that the volume of the control valve is reduced and the weight is reduced.
3, using electric actuator. It can not only reduce the air supply device and auxiliary equipment required for the pneumatic actuator, but also reduce the weight of the actuator. For example, Fisher's 9000 series electric actuators, whose Type 20 height is less than 330mm, reduce the weight of the entire control valve (with digital controller and actuator) to 20~ 32kg.
4. Rotary transformation of control valve:
Rotary control valves, such as ball valves, etc., they have the advantages of relatively small volume, small flow path resistance, large adjustable ratio, good sealing, good blocking performance, and large flow capacity, so the proportion of rotating valves increases in the new varieties of control valves. Especially in large diameter pipelines, ball valves, butterfly valves and other types of control valves are commonly used, from the perspective of foreign products in recent years
The proportion of rotary valve applications is increasing year by year.
Five, the integration of control valves:
The intelligent electric actuator adopts an integrated structure to reduce the incidence of failure, reduce cost and weight, and reduce maintenance costs.
6. Safety of control valve:
The safety of the instrument control system has been paid attention to by all aspects concerned, and the safety instrument system (81S) has increasingly high requirements for the control valve, as shown below.
1, to improve the control valve fault information diagnosis and processing requirements, not only to the control valve after the failure of passive maintenance, but also to carry out preventive maintenance and predictive maintenance of the fault stage. Therefore, it is more important to make statistics and analysis on the relevant components of the control valve and put forward maintenance suggestions in time.
2, for the control valve used in the emergency shutdown system or safety interlock system, put forward the requirements of timely, reliable and safe action. Ensure that these control valves are opened in time when they are to be opened. It can be closed in time when it is to be closed, and it can be kept in time when it is to be kept in the original operating position.
3, for the control valve used in dangerous places, the certification process should be simplified. For example, the fieldbus instrument for the safety application can be simplified to adopt the FISCO fieldbus intrinsic safety concept, which simplifies the certification process of the safety product.
4, similar to the safety of other on-site instruments, the safety of the control valve can use flameproof technology, fire prevention technology, increased safety technology, intrinsic safety technology, no spark technology; For fieldbus instrument, the concept of entity, intrinsic safety, FISCO and non-flammable (FINCO) can also be used.
7. Energy saving of control valve:
Reducing energy consumption and improving energy efficiency is a development direction of control valves. The main manifestations are as follows.
1, the use of low pressure drop ratio control valve. Reduce the proportion of the control valve in the whole system pressure drop, so as to reduce energy consumption, therefore, the design of low pressure drop ratio of the control valve is one of the development directions; Another development direction is the use of low impedance control valves, for example, the use of butterfly valves, eccentric rotary valves and so on.
2, using self-operated control valve. For example, the pressure of the medium behind the valve is directly used to form a self-reliant control system, and the energy of the controlled medium is used to control the pressure behind the valve. ,
3, the use of electric actuator control valve. The pneumatic actuator needs a certain air pressure during the entire operation of the control valve, although the amplifier with small consumption can be used, but over time, the gas consumption is still huge. The electric actuator requires power supply when changing the opening of the control valve, and can no longer be powered when the required opening is reached. Therefore, from the perspective of energy saving, the electric actuator has obvious energy-saving advantages than the pneumatic actuator.
4, using piezoelectric control valve. In the intelligent electric valve positioner, the piezoelectric control valve is used, and the air source is consumed only when the output signal is increased.
5, the use of balanced structure of the spool. Reduce the actuator thrust or pushing moment, shrink the membrane head chamber, and reduce energy requirements.
6, the use of frequency conversion speed regulation technology instead of control valve. For the application of the high voltage drop ratio, if the energy consumption is large, the frequency conversion speed regulation technology can be used, and the speed of the relevant operating equipment can be changed by the frequency converter to reduce the energy consumption.
Eight, control valve environmental protection:
Environmental pollution has become a public hazard, and the pollution of the control valve to the environment mainly includes the control valve noise and the leakage of the control valve. Among them, the pollution of the control valve noise to the environment is very serious. To this end, the development of the control valve should surround to reduce the noise of the control valve and prevent atmospheric pollution of the control valve. The performance is as follows.
1, reduce control valve noise. Various methods to reduce the noise of the control valve are developed, including the design of the flow path of the control valve, the design of the internal parts of the control valve, the analysis of the noise source and the measures to reduce the noise. The main design of noise reduction control valve and noise reduction control valve internal parts; Rational distribution of pressure drop, use of external noise reduction measures, for example, increased isolation, use of mufflers, etc.
2, reduce the air pollution of the control valve. The air pollution of the control valve refers to the "run", "take", "drop", "leak" of the control valve, which not only causes waste of materials or products, but also causes pollution to the atmospheric environment, and sometimes causes casualties or equipment explosions and other accidents. Therefore, the development of control valve packing structure and packing type, the development of control valve seal will be an important research topic in the future.