Vacuum equipment refers to a device or equipment that uses mechanical, physical, chemical or physical-chemical methods to evacuate the pumped container to obtain a vacuum. At present, the vacuum pump is the main equipment for obtaining vacuum, and it is widely used in various industries. The overall structure of the vacuum pump is generally made of metal, which is very easy to corrode. Corrosion will not only cause economic losses to the enterprise, but also damage to safety and the environment. do you know? These reasons can cause corrosion of the vacuum pump.
① Influence of material: The material selected under specific conditions is unreasonable. The material of the pump casing, sealing liquid disc and pump cover of the vacuum pump is made of gray cast iron. Although cast iron is convenient for casting parts with complex structures, cast iron has low strength and poor corrosion resistance.
② Influence of cavitation: Metal components in liquid, due to the rapid formation and collapse of vapor bubbles on their surface, cause damage with hole characteristics, which is called cavitation. Cavitation often occurs on metal surfaces where high-speed liquid flow and rapid alternating pressure changes occur. When the vacuum pump is working normally, in the suction stage, when the pressure is lower than the vapor pressure of the liquid, bubbles are formed rapidly. In the discharge stage, the bubbles are rapidly burst under pressure, and the shock wave generated is like a "water hammer", which is enough to damage the metal surface. , the exposed metal surface is further corroded by the medium.
③ Impact of impact corrosion: The high flow rate of the medium has the effect of mechanical wear, especially when the medium contains solid particles, the wear is more serious. When the liquid ring in the pump casing flows at a high speed, the passivation film on the surface is broken, the corrosion products are quickly removed, and a new passivation film is generated, which is quickly removed again, and the cycle is repeated, resulting in impact wear on the pump casing.
④ Influence of system load: When the catalyst is dry, the system needs to blow nitrogen back, and because of the leakage in the supply system, the operation system of the vacuum pump is unstable and the operation load is large. The vacuum pump has been in this unstable and high-load operation state for a long time, which aggravated the erosion of the vacuum pump, accelerated the damage of the vacuum pump, and shortened the service life of the pump.
In view of the corrosion and scouring problem of vacuum pumps, polymer composite materials can be used to implement organic coating on the surface of vacuum pumps for anti-corrosion. Polymer composites have good chemical resistance and excellent mechanical and adhesive properties. It can be widely used in corrosion, abrasion, cavitation protection and repair of equipment.
