1. Strength performance. Strength performance refers to the valve's ability to withstand the pressure of the medium. Taking pneumatic ball valves as an example, pneumatic ball valves are mechanical products that can withstand internal pressure during use. Therefore, strength and stiffness are parameters that must be paid attention to during inspection.
2.Flowing medium. After the medium flows through the valve, there will be a pressure loss (that is, the pressure difference before and after the valve), that is, the valve has a certain resistance to the flow of the medium, and the medium must consume a certain amount of energy to overcome the resistance of the valve, that is, the flow resistance coefficient.
3. Opening and closing force, opening and closing torque and opening and closing speed. During the opening and closing process of the valve, the required opening and closing force and opening and closing torque change, and their values are at the moment of closing or opening. Generally, there are no strict requirements for the opening and closing speed of valves, but some working conditions have special requirements for 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, etc. This should be considered when selecting the valve type.
4. Sealing performance. The sealing performance of the valve refers to the ability of each sealing part of the valve to prevent medium leakage, which is an important technical performance indicator of the valve. There are three sealing parts of the valve: the contact between the opening and closing parts and the two sealing surfaces of the valve seat, the fit between the packing and the valve stem and stuffing box, and the connection between the valve body and the valve cover. The leaks caused by these three places involve internal leakage and external leakage, but no matter what kind of leakage it is, it will lead to waste of raw materials and damage to the machine. We often divide valves into hard-sealed valves and soft-sealed valves based on different sealing materials (common valves include soft-sealed butterfly valves, hard-sealed ball valves, etc.).
5. Action sensitivity and reliability. This parameter represents the sensitivity of the valve to parameter changes. This parameter has special requirements for some throttle valves, safety valves and other valves, and is one of the indicators that needs to be continuously optimized.
6. Service life. This parameter represents the durability of the valve and reflects the quality of the valve to a certain extent. It is usually expressed by the number of opening and closing times that can ensure the sealing requirements, or it can also be expressed by the use time.
