There are nine main functions of the regulating valve: 1 regulation; 2 cutting; 3 overcoming pressure difference; 4 anti-blocking; 5 corrosion resistance; 6 pressure resistance; 7 temperature resistance; 8 weight; 9 appearance. Let's learn about some functions of the regulating valve together. 

 I. Anti-jam blocking performance 

 For the adjustment of unclean media, or even if it is a clean medium, welding slag and other debris in the pipeline may cause the control valve to be blocked or stuck. Therefore, the regulating valve should have a good anti-blocking function so as not to affect the normal use of the regulating valve. 

 The most anti-jamming is the rotary valve with the simplest flow path, such as ball valves, butterfly valves, eccentric valves, and multi-function regulating valves. Control valves with complex flow routes and control valves guided by upper and lower bushings are easy to cause jams, such as single-seat valves, double-seat valves, sleeve valves, etc. Rotary valves not only have good anti-blocking function, but also have small leakage and large pressure difference, so their use will become more and more widely. 

 II. Corrosion resistance 

 Corrosion resistance of the regulating valve: that is, the regulating valve is resistant to the corrosion and erosion of the medium to improve the service life of the regulating valve. 

 The corrosion of the regulating valve is caused by the chemical properties of the medium, and corrosion-resistant materials are usually used to solve it. 

 The erosion of the regulating valve is caused by high-speed flowing media, granular media and cavitated media that produces flash evaporation. The solution is to select wear-resistant materials and adopt anti-vapor erosion and anti-flash erosion measures in the structure. If the high-pressure regulating valve, the regulating valve with large pressure difference work, and the regulating valve containing particle media need to focus on this problem. 

 III. Cutting performance 

 The cut-off function of the regulating valve: expressed by the leakage index of the regulating valve, the cut-off usually refers to the leakage of less than 0.001%, and the highest level is level VI (bubble level). With the continuous development and innovation of processing technologies such as material processing and machine tool equipment, the problem of large leakage of domestic regulating valves has also made good progress, basically solving most of the leakage index requirements. 

 IV. Overcome the differential pressure performance 

 Overcoming the pressure difference performance of the regulating valve: It is usually expressed by the allowable pressure difference when the regulating valve is closed. The larger the allowable pressure difference of the regulating valve, the better the overcoming pressure difference performance of the regulating valve. In the specific control valve selection work, if the problem of overcoming the pressure difference is not considered, it is easy for the valve core to be opened by the pressure difference, resulting in problems such as the control valve not closing and the leakage exceeding the standard. Therefore, to ensure the cutting performance of the regulating valve, it is necessary to overcome the working pressure difference when the regulating valve is closed. 

 Usually, the allowable pressure difference of single-sealed regulating valves is small, such as single-seat valves, angle valves, diaphragm valves, three-way valves, etc., and double-sealed regulating valves and rotary regulating valves allow a large pressure difference, such as double-seat valves, ball valves, and multi-function regulating valves. 

 From the perspective of the relationship between the amount of leakage and overcoming the pressure difference: 

 1. The single-sealing regulating valve leaks little but the allowable pressure difference is small; 

 2. The double seal valve leaks a lot, and the pressure difference is allowed to be large; 

 3. Only rotary regulating valves have small leakage and large pressure differences, which is one of the important reasons why rotary valves are used more and more. 

 V. Pressure resistance 

 Pressure resistance of the regulating valve: It reflects the strength and safety indicators of the regulating valve, that is, the medium cannot leak out through the seal and the valve body defect. 

 When the regulating valve leaves the factory, it is usually tested with a pressure of 1.5 times PN for pressure resistance test. For high-pressure media, it is best to use a forged structure; the compressive strength of cast iron regulating valves is the lowest, and it is generally recommended to use cast steel valves instead. 

 VI. Temperature resistance 

 High temperature will reduce the strength of the valve body material. In order to meet the requirements of the strength index of the regulating valve under different temperature conditions, the temperature resistance of the regulating valve material must be carefully considered, and the structure of the regulating valve must be reasonably designed to ensure that the regulating valve has good strength and safety guarantee at working temperature. 

 In the consideration of temperature resistance, in addition to considering the temperature, the impact of pressure and temperature difference (such as pressure considering pressure difference) should also be considered. 

 VII. Appearance and weight performance 

 With the continuous development of science and technology, the roughness and bulkiness of regulating valves are increasingly not suitable for the needs of modern industry. People began to pursue the exquisite appearance and instrumentation of the regulating valve; under the premise of meeting the required functions, they should be as light and miniaturized as possible. This can save material costs, facilitate transportation and installation, and reduce the maintenance workload of equipment.