In the development process of the flanged gate valve, we must pay attention to the six technical indicators of the flanged gate valve, so that the flanged gate valve can be better developed, so what are the six technical indicators of the flanged gate valve?
1. The sealing performance of flanged gate valve
The sealing performance of the valve refers to the ability of each sealing part of the valve to prevent the leakage of the medium, which is an important technical performance index 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 cooperation between the packing and the valve stem and the stuffing box; the connection between the valve body and the valve cover.
The leakage in the former part is called internal leakage, which is commonly referred to as lax closure, which will affect the ability of the flanged gate valve to cut off the medium. For cut-off valves, internal leakage is not allowed.
The leakage in the latter two places is called external leakage, that is, the medium leaks from the inside of the valve to the outside of the valve. External leakage will cause material loss, pollute the environment, and even cause accidents in severe cases.
For flammable, explosive, toxic or radioactive media, leakage is not allowed, so the valve must have reliable sealing performance.
2. Flow medium of flanged gate valve
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 consumes a certain amount of energy to overcome the resistance of the valve.
Considering energy saving, when designing and manufacturing the valve, the resistance of the valve to the flowing medium should be reduced as much as possible.
3. Opening and closing force and opening and closing torque of flanged gate valve
Opening and closing force and opening and closing torque refer to the force or torque that must be applied to the valve to open or close. When closing the valve, it is necessary to form a certain sealing pressure between the opening and closing parts and the two sealing surfaces of the valve seat.
At the same time, it is necessary to overcome the friction between the valve stem and the packing, between the valve stem and the thread of the nut, the support at the end of the valve stem and other frictional parts.
Therefore, a certain closing force and closing torque must be applied. During the opening and closing process of the valve, the required opening and closing force and opening and closing torque vary.
Its maximum value is at the final moment of closing or the initial moment of opening, and the valve should be designed and manufactured to reduce its closing force and closing moment.
4. The opening and closing speed of the flanged gate valve
The opening and closing speed is expressed by the time required for the valve to complete an opening or closing action. Generally, there is no strict requirement for the opening and closing speed of the valve.
However, some working conditions have special requirements on the opening and closing speed. Some require the flanged gate valve to be opened or closed quickly to prevent accidents, and some require slow closing to prevent water hammer. This should be taken into account when selecting the valve type.
5. Action sensitivity and reliability of flanged gate valve
This refers to the sensitivity of the valve to respond to changes in medium parameters. For throttle valves, pressure reducing valves, regulating valves and other valves used to adjust medium parameters, as well as safety valves, steam traps and other valves with specific functions, their functional sensitivity and reliability are very important technical performance indicators.
6. Service life of flanged gate valve
It indicates the durability of the valve, is an important performance indicator of the valve, and has great economic significance. It is usually expressed by the number of times of opening and closing that can ensure the sealing requirements, and it can also be expressed by the use time.