What are the reasons for the damage to the sealing surface of the card sleeve needle valve


Release time:

2024-01-18

The sealing element of the needle valve plays a role in cutting off and connecting, adjusting, distributing, separating, and mixing media on the channel. Therefore, the sealing surface is often corroded, eroded, and worn by the media, which is easy to damage. The causes of damage to the sealing surface of the card sleeve needle valve can be divided into two types: artificial damage and natural damage. Human damage is caused by factors such as poor design, poor manufacturing, improper material selection, improper installation, poor use, and inadequate maintenance. Natural damage refers to the wear and tear of the valve under normal working conditions, which is caused by inevitable corrosion and erosion of the sealing surface by the medium. The causes of damage to the sealing surface of the card sleeve needle valve are roughly as follows:

The sealing element of the needle valve plays a role in cutting off and connecting, adjusting, distributing, separating, and mixing media on the channel. Therefore, the sealing surface is often corroded, eroded, and worn by the media, which is easy to damage. The causes of damage to the sealing surface of the card sleeve needle valve can be divided into two types: artificial damage and natural damage. Human damage is caused by factors such as poor design, poor manufacturing, improper material selection, improper installation, poor use, and inadequate maintenance. Natural damage refers to the wear and tear of the valve under normal working conditions, which is caused by inevitable corrosion and erosion of the sealing surface by the medium.
The causes of damage to the sealing surface of the card sleeve needle valve are roughly as follows:
1. The poor processing quality of the sealing surface is mainly manifested in defects such as cracks, pores, and inclusions on the sealing surface, which are caused by improper selection of welding and heat treatment specifications and poor operation during the welding and heat treatment process. The hardness of the sealing surface is too high or too low, which is caused by improper material selection or heat treatment. The uneven hardness and corrosion resistance of the sealing surface are mainly due to blowing the underlying metal onto it during the welding process, Diluted the alloy composition of the sealing surface. Of course, there are also design issues involved. 2. Damage caused by improper selection and poor operation. The main manifestation is that the valve was not selected according to the operating conditions, and the cut-off valve was used as a throttle valve, resulting in excessive closing pressure, too fast or not tightly closed, causing erosion and wear on the sealing surface.
3. Improper installation and inadequate maintenance of the sleeve needle valve resulted in abnormal operation of the sealing surface, causing the valve to operate with defects and premature damage to the sealing surface.
4. Chemical corrosion of the medium, the medium around the sealing surface directly interacts with the sealing surface to corrode the sealing surface without generating an electric current.
5. Electrochemical corrosion occurs due to factors such as mutual contact between sealing surfaces, contact between sealing surfaces and closing bodies and valve bodies, as well as differences in medium concentration and oxygen concentration, which can lead to potential differences and electrochemical corrosion, resulting in corrosion of the sealing surface on the anode side.
6. The erosion of the medium is the result of wear, erosion, and cavitation of the sealing surface during the flow of the medium. At a certain speed, the floating fine particles in the medium collide with the sealing surface, causing local damage. The high-speed flowing medium directly washes the sealing surface, causing local damage. When the medium mixes and vaporizes locally, bubbles burst and impact the surface of the sealing surface, causing local damage. The erosion of the medium, combined with the alternating effect of chemical corrosion, will strongly corrode the sealing surface.
7. Mechanical damage can cause scratches, bumps, and squeezing on the sealing surface during opening and closing. Under the action of high temperature and high pressure, atomic permeation occurs between the two sealing surfaces, resulting in adhesion. When the two sealing surfaces move towards each other, the adhesive area is prone to tearing. The higher the surface roughness of the sealing surface, the more likely this phenomenon is to occur. During the closing process of the sleeve needle valve and the valve disc during the reseating process, the sealing surface may be damaged and squeezed, causing local wear or pressure marks on the sealing surface.
8. Fatigue damage: During long-term use, the sealing surface of the Sanjing valve is subjected to alternating loads, resulting in fatigue, cracks, and delamination on the sealing surface. Rubber and plastic are prone to aging after long-term use, resulting in poor performance.