19
2023-05
Today, I will analyze the main technical performance of brass valves from seven aspects: light performance, sealing performance, flowing medium, opening and closing force and torque, opening and closing speed, action sensitivity and reliability, and service life. I hope it will be helpful for you to understand brass valve products.
1. strength performance
The strength performance of copper valves refers to the ability of copper valves to withstand medium pressure. Copper valves are mechanical products that bear internal pressure, so they must have sufficient strength and stiffness to ensure long-term use without cracking or deformation.
2. sealing performance
The sealing performance of copper valve refers to the ability of each sealing part of copper valve to prevent medium leakage. It is the most important technical performance index of copper valve. There are three sealing parts of the copper valve: the contact between the two sealing surfaces of the hoist and the valve seat; Packing, valve stem and stuffing box; Connection between valve body and bonnet. The leakage in the former part is called internal leakage, that is, if it is not closed tightly, it will affect the ability of the copper valve to cut off the medium. For block valves, internal leakage is not allowed. The leakage at the last two places is called external leakage, that is, the medium leaks from inside the valve to outside the valve. External leakage will cause material loss, pollute the environment, and even cause accidents in serious cases. For flammable, explosive, toxic or radioactive media, leakage is not allowed, so the copper valve must have reliable sealing performance.
3. flowing medium
After the medium flows through the copper valve, there will be pressure loss (i.e. the pressure difference between the front and back of the copper valve), that is, the copper valve has a certain resistance to the medium flow, and the medium will consume a certain amount of energy to overcome the resistance of the copper valve. From the perspective of energy conservation, when designing and manufacturing copper valves, the resistance of copper valves to flowing media should be reduced as much as possible.
4. hoisting force and moment
The opening and closing force and torque refer to the force or torque that must be applied to open or close the copper valve. When closing the copper valve, it is necessary to form a certain sealing specific pressure between the opening and closing parts and the two sealing surfaces of the hair seat. At the same time, it is also necessary to overcome the friction between the valve rod and the packing, between the threads of the valve rod and the nut, at the end support of the valve rod and other friction parts. Therefore, a certain closing force and closing torque must be applied. During the opening and closing process of the copper valve, the required opening and closing force and torque are variable, Its maximum value is at the final instant of closing or the initial instant of opening. When designing and manufacturing copper valves, try to reduce their closing force and closing torque.
5. opening and closing speed
The opening and closing speed is expressed by the time required for the copper valve to complete an opening or closing action. Generally, there are no strict requirements on the opening and closing speed of copper valves, but some working conditions have special requirements on the opening and closing speed. For example, some require rapid opening or closing to prevent accidents, and some require slow closing to prevent water hammer. This should be considered when selecting the type of copper valves.
6. action sensitivity and reliability
This refers to the sensitivity of copper valves to changes in medium parameters. For copper valves used to regulate medium parameters, such as throttle valve, pressure reducing valve and regulating valve, and copper valves with specific functions, such as safety valve and steam trap, their functional sensitivity and reliability are very important technical performance indicators.
7. service life
It indicates the durability of copper valves, is an important performance index of copper valves, and has great economic significance. It is usually expressed by the number of opening and closing times that can ensure the sealing requirements, and it can also be expressed by the service time.
