Valve is used to open close the pipeline, control the flow direction, adjust control the parameters of the medium (temperature, pressure flow). The sealing surface on the water bag valve is used to cut off, connect, adjust, distribute, separate mix media. Therefore, the sealing surface is usually corroded worn by the medium, which is very easy to be damaged.
The reasons of damaging the sealing surface of water bag valve are divided into artificial damage natural damage. Human damage is caused by excessive design, incorrect manufacturing, incorrect material selection, improper installation, improper use ineffective maintenance. Natural damage refers to the wear of valve under normal working condition. The damage is caused by inevitable corrosion erosion of the sealing surface by the medium.
The erosion of medium is the result of abrasion, flushing cavitation of sealing surface when the medium is active. At a certain speed, the floating fine particles in the medium collide with the sealing surface cause local damage. The high-speed moving medium directly washes the sealing surface to cause local damage. When the medium is mixed vaporized locally, the gas generating bubble blasting impacts the sealing surface, resulting in local damage. Medium erosion chemical erosion alternate action, will strongly erode the sealing surface.
Electrochemical corrosion, contact between sealing surfaces, contact between sealing surfaces sealing body valve body, as well as medium concentration difference, oxygen concentration difference other reasons, will produce potential difference electrochemical erosion, resulting in corrosion of sealing surface on anode side.
In the case of no electric current generated by the medium near the sealing surface, the medium directly reacts with the sealing surface erodes the sealing surface. Improper installation maintenance lead to the abnormal working of sealing surface, the water bag valve operates with fault, which damages the sealing surface prematurely.
Fatigue damage: when the sealing surface is used for a long time, under the action of alternating load, the sealing surface will cause fatigue, fracture falling off. Long term use of rubber plastics can lead to aging, which weakens performance.