How to prevent corrosion of Roots vacuum unit

The roots vacuum unit is equipped with an eccentric rotor with fixed blades, which throws water (liquid) to the stator wall. The water (liquid) forms a liquid ring concentric with the stator. The liquid ring and the rotor blades together form a rotary variable volume vacuum pump with variable volume.
Now in some large-scale chemical plants and highly corrosive industries, the material requirements of Roots vacuum unit are more and more stringent. In order to reduce the cost, some factories will require the impeller of Roots vacuum unit to be stainless steel impeller or the overflow parts to be stainless steel, but in the actual use process, the pump will be seriously corroded in a few months, which actually greatly increases the production Cost of production. In view of this situation, our company's engineers have studied a set of appropriate solutions through continuous tests.
The solution is to armour chemical ceramics inside the pump body and the cast iron shell with two side covers, fill the binder between the cast iron shell and the chemical ceramics, and seal the end face of the joint with resin. The impeller of Borui steel is fixed on the main shaft with a steel key. A Borui steel shaft sleeve is installed on both sides of the impeller to protect the main shaft from contacting with corrosive media. The shaft seals at both ends are mechanical seals.
The application of Roots vacuum unit made of the above anti-corrosion measures in the production process of selenium shows that its service life is more than 8 times longer than that of ordinary cast iron pump. The latter can not withstand the corrosion of sulfur dioxide and selenium dioxide gas, and the pump is damaged after one to two months, which seriously affects the continuous industrial production and increases the cost of spare parts and maintenance. If the vacuum unit is made of stainless steel, the manufacturing cost of the pump will be increased by more than three times. Some manufacturers try to spray corrosion-resistant materials on the overflow part of the vacuum unit by thermal spraying method, but it fails because the bonding strength between the sprayed materials and the body is weak and it can not withstand the erosion of the liquid ring.

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