What affects valve sealing issues?

What affects valve sealing issues?

1. Valve sealing secondary structure

Under changes in temperature or sealing force, the structure of the sealing pair will undergo changes. And this change will affect and alter the interaction force between the sealing pairs, thereby reducing the sealing performance of the valve. Therefore, when selecting seals, it is important to choose seals with elastic deformation. Meanwhile, attention should also be paid to the width of the sealing surface. The reason is that the contact surface of the sealing pair cannot fully match, and as the width of the sealing surface increases, the required sealing force needs to be increased.

2. Valve sealing surface pressure ratio

The specific pressure of the sealing surface affects the sealing performance and service life of the valve. Therefore, the specific pressure of the sealing surface is also a very important factor. Under the same conditions, a high specific pressure can cause damage to the valve, but a low specific pressure can cause valve leakage. Therefore, we need to fully consider the suitability of specific pressure during design.

3. Physical properties of valve media

The physical properties of the medium also affect the sealing performance of the valve. These physical properties include temperature, viscosity, and surface hydrophilicity. The temperature change not only affects the relaxation of the sealing pair and changes in the size of the parts, but also has an inseparable relationship with the viscosity of the gas. The viscosity of gas increases or decreases with the increase or decrease of temperature.

Therefore, in order to reduce the impact of temperature on the sealing performance of the valve, we need to design the sealing pair as a valve with thermal compensation such as an elastic valve seat. Viscosity is related to the permeability of fluids. When under the same conditions, the higher the viscosity, the smaller the fluid's permeability. Surface hydrophilicity refers to the removal of a thin film on a metal surface. Because this thin oil film can damage the hydrophilicity of the surface and block the channels of the fluid.

4. Quality of valve sealing pair

The quality of the sealing pair mainly refers to the quality control of material selection, matching, and manufacturing accuracy. For example, the sealing surface between the valve disc and the valve seat matches well, which can improve the sealing performance. The characteristic of high circumferential waviness is its good labyrinth sealing performance. Valve leakage is very common in daily life and production, which can cause waste or pose a danger to daily life. For example, water valve leakage can lead to serious consequences, such as toxic, harmful, flammable, ex plosive, and corrosive medium leakage in the chemical industry, posing a serious threat to personal safety, property safety, and environmental pollution accidents.

A valve that relies on external force to rotate and open and close is designed with a sealing device. It is used to install a certain number of packing sealing rings in the packing culvert to achieve a sealing effect. But what is the sealing situation? The leakage at the packing of the valve is one of the parts in the valve that are prone to leakage faults, but there are generally two reasons for this.