From the analysis of the cause of the damage of the seal, we can see that it is necessary to choose the proper sealing material, the correct seal design and the processing method to improve the quality and the service life of the valve seal.

First, fatigue damage, seals in the long-term use, the valve under the effect of alternating load, resulting in the appearance of the sealing surface fatigue, cracks and stripped layer. Rubber and plastics, through long-term use, are simple, aging and aging, resulting in poor function.

Two, mechanical damage, skeleton oil seal seals in the opening and closing will occur in our fire, bruise, bruise, extrusion and other damage. Two between the seals, under the effect of high temperature and high pressure, the firing atoms are saturated with each other. When the two seals move each other, the adhesion is simply pulled and ripped.  The higher the roughness of the seal is, the simpler the appearance is. During the blocking process, the disc will bump and crush the sealing cover in the process of returning to the seat, causing the seal surface to be worn or burned.

Three, the electrochemical erosion, the touch of sealing surface of oil seal, the touch of sealing surface and blockade body and valve body, and the difference of concentration and oxygen concentration between the medium and other causes, the ignition potential difference will occur, the ignition electrochemical erosion occurs, and the sealing surface of the anode one side is eroded.

Four, the chemical erosion of the medium, the medium near the seal without ignition current, the medium directly with the sealing part to play a chemical effect, erosion seal.

Five, improper installation and poor repair cause the seal work is not normal, the valve is ill, and premature damage to the seal.

Six. Improper selection and bad handling. The first table is not used to choose the valve according to the working condition, and the blocking valve is used as the throttle valve, which causes the blockade to be overpressure and the blockade is too fast or the blockade is not strict, so that the seal is eroded and worn.

Seven. The quality of the sealing parts is not good. The first table is that there are cracks, holes and ballast on the seal. It is due to improper selection of the surfacing and heat treatment scale, and bad handling in the process of overlaying and heat treatment. The sealing ring is too hard or too low, which is due to improper selection of material or improper heat treatment. The hardness of the sealing ring is uneven and the erosion is not resistant. The first is that the bottom metal is blown to the top of the metal in the process of surfacing, and the alloy composition of the seal ring is weakened. Of course, there are also portrayed topics.

Eight. The erosion of the medium is the result of the wear, washing and cavitation of the seal when the medium flows. Under the necessary speed, the floating fine particles in the medium touch the sealing ring of the combination washer, so that it forms some damage, and the high speed flowing medium can flush the seal directly, and make it form some damage. When the medium is mixed and some vaporization, the ignition bubble explode and shocks the surface of the seal surface and forms some damage. The erosion of the medium and the substitution effect of chemical erosion will corrode the seals severely.

The reasons for the damage of the sealing surface can be summarized as follows.

1, the cause of damage to the sealing surface is man-made damage and natural damage two kinds.

1) man-made damage is caused by such factors as poor description, poor production, poor material selection, improper installation, poor utilization and poor repair.

2) natural damage is the wear and tear of the valve under normal working conditions, and the damage caused by the medium to the inevitable erosion and erosion of the sealing surface.

2. Due to the effect of sealing and connecting, adjusting and distributing, separation and mixing medium on the valve channel, the sealing appearance is often eroded, eroded and worn by the medium, and it is simple damage.