Rotary vacuum pumps suffer from crystalline corrosion when pumping formaldehyde gas; what material should be used?
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Our company’s Roots vacuum pumps suffer from crystalline corrosion when pumping formaldehyde gas; the current material used is carbon steel. It is prone to crystallization and corrosion. What material should be used, or can a polymer material be sprayed on?
It’s easy to solve; there’s a problem with the design of the Roots vacuum pump. The coating of polymer materials on the rotor has nothing to do with crystalline corrosion – does applying a coating somehow prevent crystallization? Furthermore, since the linear expansion coefficient of polymer materials differs from that of the rotors in rotary vane pumps, different thermal expansion coefficients arise during the operation of the pump, which can lead to detachment over time
I wonder what the temperature is? When applying polymer materials, the operating conditions must be considered!
I ask the original poster: Has the crystallization issue been resolved?
Gaseous formaldehyde automatically polymerizes at room temperature to form cyclic trimethylolpropane and similar compounds
Crystallization or not has little to do with the material itself; it’s mainly a matter of the manufacturing process! I’ve learned it
How to solve it? Educational background. . . .
Add a steam pipe to the inlet pipe and utilize automatic control. Blow-down treatment is carried out after each use to dissolve surface crystals and residues, as well as the accumulation of crystals on the surface when it is at low temperature during shutdown. After purging, dry using the residual heat. Nitrogen protection is introduced. This can resolve the aforementioned issues.