The Basic Knowledge of the Safety Valve (3)
The difficulty of designing and manufacturing the safety valve
How to ensure accurate popping, good mechanical property, effective sealing and steady discharging of safety valves involves many basic subjects such as hydrodynamics, structural mechanics and mechanics of materials. In addition, mathematical models must be set up.
In recent years, the quality and the technological level of the Chinese safety valve are continuously improved. Most of the users have recognized the Chinese safety valve. For users, the premise of choosing the safety valve products is safety and stability.
The following is the main difficulty in manufacturing the safety valve
The spring is one of the key components of the safety valve. The quality of the spring affects the stability of safety valves’ performance directly. The overall pressure of the safety valve is obtained by adjusting the compressing volume of the spring. When the structure size of the safety valveis determined, the stability of elastic coefficient of the spring determines whether discharging pressure, reseating pressure, opening height and mechanical properties of the safety valve can meet the relevant standards or not. The elastic coefficient of the spring is affected by temperature. From the perspective of automatic control, the temperature drift and the zero drift of the spring are related to the control of the temperature of the spring’s material, especially the special spring.
From the perspective of industrial applications, the safety valve is the static equipment, but it has an internal moving parts. The safety valve should have reasonable structure and good mechanical property to ensure that there is not any jam occurring in the running process.
Set up the fluid mechanics model of the valve body’s structure and internal structure.
The structure of the nozzle must be designed properly to ensure that the medium can be discharged steadily.
The sealing performance of the safety valve is obtained mainly by the valve clack and the valve seat. The working accuracy has a great influence on the sealing performance of the safety valve. Build-up welding of hard alloy on the surface of the safety valve is the usually way to improve the sealing performance and wearing life of the safety valve. The technology of build-up welding is relatively complex and it is difficult to control. These difficulties can be improved through improvement of the technology. The main difficulty is to control the quality. Even if all the parts have passed the exam, the operation level and working attitude of the operator and the control of the testing process are likely to cause the human error in the assembly process, affecting the performance of the safety valve.
Source: China Valves Manufacturer – Yaang Pipe Industry (www.ugsteelmill.com)