Analysis on Damage Factors of Dry Screw Vacuum Pump

I. Cause Analysis of Rotor Surface Corrosion of Screw Pump

The feed medium of vacuum pump contains sulphur dioxide and water. Sulfur dioxide combines with water to form sulfite. Sulfite corrodes metals. To prevent corrosion of rotors and pump chambers, Teflon coatings are applied on the surface of rotors and pump chambers. Corrosion in the rotor and pump cavity indicates that the layers are destroyed and sulfite has corroded to the pump cavity.

II. Cause Analysis of Damage to Rotor and Pump Cavity Teflon Layer

There are three possible causes of damage to the surface layers of the rotor and pump cavity:

First: Solid particles enter the pump chamber, causing coating damage.

Second: Chemicals form gum on pump chamber and rotor, gum carbonizes and hardens, destroying rotor and pump chamber coating.

Third: Other reasons.

1. Destruction analysis of solid particles

Inspect the pump inlet equipment and piping, no free moving solid particles such as metal debris, iron cutting, etc. were found.

2. Analysis of Carbon Deposition Damage of Gum

Attachment is found on the inner wall of the inlet pipe of the pump. The substance is dark brown. After analysis, it contains iron, carbon, oxygen, etc. It is a polymer such as butadiene and sulfolane, which are bonded to the inner wall of the pipe. If the material is bonded to the pump cavity and rotor surface, it tends to carburize and harden, thereby destroying the rotor surface layer.