Causes damage to the sealing surface of the valve

The causes of damage to the sealing surface can be summarized as follows.

The cause of damage to the sealing surface is either damage or natural damage. Man-made damage, natural damage caused by factors such as poor design, poor manufacturing, improper material selection, improper installation, poor use and poor maintenance, wear under normal valve conditions, inevitable erosion and erosion of the sealing surface by the medium, etc. Damage caused.

Mechanical damage, the sealing surface will be damaged by scratches, bumps, crushing, etc. during opening and closing. Between the two sealing surfaces, under the action of high temperature and high pressure, atoms permeate and ooze out, and blocking occurs. When the two sealing faces move relative to each other, the adhesion is easily pulled. The higher the roughness of the sealing surface, the easier it is. During the sealing process, the valve flap will damage and crush the sealing surface during the returning process, causing partial wear or indentation of the sealing surface.

The erosion of the medium, the result of wear, rinsing, and cavitation of the sealing surface when the medium is active. When the medium is at a certain speed, the floating fine particles in the medium resist the offensive sealing surface, causing local damage. The high-speed moving medium directly flushes the sealing surface, causing local damage, medium mixed flow and local vaporization, gas production and blasting Impact on the surface of the sealing surface, causing local damage. The erosion of the medium and the alternating chemical attack will strongly etch the sealing surface.

Electrochemical erosion, contact between the sealing surfaces, contact between the sealing surface and the sealing body and the valve body, and the difference in concentration of the medium, oxygen concentration, etc., cause a potential difference, causing electrochemical erosion, causing the sealing surface of the anode side to be eroded.

Chemical attack of the medium, the medium near the sealing surface does not generate current, the medium directly chemicalizes with the sealing surface, eroding the sealing surface.

The device is not correct and the maintenance is not good, resulting in the sealing surface working abnormally. The valve is sick and runs, and the sealing surface is damaged prematurely.

Damage caused by improper selection and poor control. It mainly indicates that the valve is used in the absence of the working condition, and the shut-off valve is used as a throttle valve, resulting in a large closing pressure and a too fast closing or a tight sealing, so that the sealing surface is eroded and worn.

The sealing surface is of poor quality, mainly indicating defects such as cracks, pores and pinching on the sealing surface, because the improper selection of the surfacing and heat treatment specifications and the poor control of the sealing surface during the surfacing and heat treatment process are too high. Or too low, because the hardness of the sealing surface is uneven and the corrosion is not uniform due to improper selection of materials or improper heat treatment, mainly because the underlying metal is blown onto the surface during the surfacing process to dilute the alloy composition of the sealing surface. There are also design issues in it.