What are the main factors affecting the valve seal?
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Release Time：2020-07-02
Valve leakage is very common in industrial production, and the impact is very large. A valve that relies on external force to rotate and drive to open and close is designed with a sealing device, which is used to install a certain number of packing seals in the packing culvert to achieve the sealing effect. The leakage of the valve packing is one of the most prone parts of the valve to leak. The reasons are as follows: 1. The structure of the sealing pair changes when the temperature or sealing force changes. And this change will affect and change the sealing force between each other, so that the valve sealing performance is reduced. Therefore, when selecting a seal, a seal with elastic deformation must be selected. At the same time, also pay attention to the width of the sealing surface. The reason is that the contact surface of the sealing pair can not be completely consistent, when the sealing surface width increases, it is necessary to increase the sealing force required. 2. The specific pressure of the sealing surface affects the sealing performance of the valve and the service life of the valve. Therefore, the sealing surface pressure is also a very important factor. Under the same conditions, the pressure is too large to cause damage to the valve, but the pressure is too small to cause valve leakage. Therefore, we need to fully consider the suitability of the specific pressure in the design. The physical properties of the medium also affect the sealing performance of the valve. These physical properties include temperature, viscosity, and hydrophilicity of the surface. Temperature changes not only affect the relaxation of the sealing pair and the change of the size of the parts, but also have a close relationship with the viscosity of the gas. The gas viscosity increases or decreases as the temperature increases or decreases. Therefore, in order to reduce the degree of influence of temperature on the sealing performance of the valve, we should design the valve with thermal compensation, such as elastic valve seat. Viscosity is related to the ability of the fluid to penetrate. When under the same conditions, the greater the viscosity, the smaller the permeability of the fluid. Surface hydrophilicity means that when there is a film on the metal surface, the film should be removed. Because this layer is very thin oil film, will destroy the surface of the hydrophilic, resulting in blockage of the fluid channel. 4. The quality of the sealing pair The quality of the sealing pair mainly means that we have to check the selection, matching and manufacturing accuracy of materials. For example, the valve and valve seat sealing surface is consistent, can improve sealing.
Valve leakage is very common in industrial production, and the impact is very large. A valve that relies on external force to rotate and drive to open and close is designed with a sealing device, which is used to install a certain number of packing seals in the packing culvert to achieve the sealing effect. The leakage of the valve packing is one of the most prone to leakage in the valve. The reasons are as follows:
1. Sealing sub-structure
Under the change of temperature or sealing force, the structure of the sealing pair will change. And this change will affect and change the sealing force between each other, so that the valve sealing performance is reduced. Therefore, when selecting a seal, a seal with elastic deformation must be selected. At the same time, also pay attention to the width of the sealing surface. The reason is that the contact surface of the sealing pair can not be completely consistent, when the sealing surface width increases, it is necessary to increase the sealing force required.
2. Sealing surface specific pressure
The specific pressure of the sealing surface affects the sealing performance of the valve and the service life of the valve. Therefore, the sealing surface pressure is also a very important factor. Under the same conditions, the pressure is too large to cause damage to the valve, but the pressure is too small to cause valve leakage. Therefore, we need to fully consider the suitability of the specific pressure in the design.
3. Physical properties of the medium
The physical properties of the medium also affect the valve sealing performance. These physical properties include temperature, viscosity, and hydrophilicity of the surface. Temperature changes not only affect the relaxation of the sealing pair and the change of the size of the parts, but also have a close relationship with the viscosity of the gas. The gas viscosity increases or decreases as the temperature increases or decreases. Therefore, in order to reduce the degree of influence of temperature on the sealing performance of the valve, we should design the valve with thermal compensation, such as elastic valve seat. Viscosity is related to the ability of the fluid to penetrate. When under the same conditions, the greater the viscosity, the smaller the permeability of the fluid. Surface hydrophilicity means that when there is a film on the metal surface, the film should be removed. Because this layer is very thin oil film, will destroy the surface of the hydrophilic, resulting in blockage of the fluid channel.
4. Quality of sealing pair
The quality of the sealing pair mainly means that we have to check the selection, matching and manufacturing accuracy of materials. For example, the valve and valve seat sealing surface is consistent, can improve sealing.
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