Causes of Abrasion Problems in Helical Rotor Pumps?

January 12, 2018

While its armour-plated rotor smoothly delivers a turgid load, a nominated helical rotor pump functions flawlessly. The long screw-like mechanism operates well within its design parameters, it creates packets of viscous fluid, and the flow is regulated. There is, however, an adverse condition accompanying that smoothly regulated stream. Suspended in the fluid, abrasive materials are scraping against the chrome-plated rotor. There, between the rotor and stator, what's happening?

The Importance of Stator Conformity

Sure, fine slurry mixes do impact rotor performance. Right now, though, we're more concerned about what's taking place at the sealing points that occur between the helical metal ridges and the elastomeric stator. As long as this seal is properly maintained, the fluid packets move as a shear-free stream. Currently, in this hypothetical failure scenario, that seal is compromised. The stator is swelling or the chrome plating is damaged. Because of that tiny gap, the abrasive particles are creating an interference fit. Imagine the pressure increase that occurs here, with the dirty film forcing the coarse material into a region between the rotor and stator, a region that should act as a wiping seal. Left to its own devices, this abrasive load will leave deep scores in the rotor plating. As for the stator polymer, tough though it undoubtedly is, the material will deform when it's subjected to this particle-induced seal penetrating effect.

Cracking Suspended Fluid Loads

Durable helical rotor pumps are designed to convey many different fluid types. However, if that fluid is caustic, then a chemical reaction can take place. The response to this aggressive chemical attack is a surface breakdown, a disintegration of the toughened alloy skin. Temperature extremes worsen this chemical assault, as do the rough-edged particles suspended in that fluid stream. Even when those physically coarse slurry surges attack without a caustic element, the damage caused by this mechanically active discharge factor can be extreme. In the construction industry, for example, gypsum slurries cut into the rotor. Meanwhile, on a farm or in an agricultural facility, it's milk or the acid contained in some animal offal that acts as a caustic fluid, even when there are no hard-edged powders in the stream.

Curiously enough, the same disastrous conditions are repeated when there's a dry flow. Instead of a corrosive chemical or a viscous, semi-solid stream full of hard grains, the slurry is dry. As we'd expect, that dry load can really cause some damage. Granulated sugar, granite dust, sand and grout, any of these desiccated materials contains enough power to damage a helical rotor pump.

Contact Alpha Pumps:

Phone:    (03) 9311 7188
Fax:          (03) 9364 9554
Mobile:    0403 030 830

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