Blowers

Material Handling Blowers and grades of Abrasion Resistant Construction.

 Most common form of wear plate is mild-steel floor plate, welded onto the Blower blades and onto the back and center plates in the areas where erosive particles impinge on the Blower wheel. The raised pattern on the plate has the effect of deflecting erosive particles away from the blade surface so that wear may actually be less than with another harder wear material.

 One advantage of using a relatively soft sacrificial material for wear protection is that wear patterns on a new Blowers are often unknown. After a few months or years of service, with frequent inspection, the areas of greatest wear can be The mild-steel wear plates can be removed and harder protective material placed where it is really needed. The most commonly used hard. faced wear plate is chromium carbide weld overlay, applied on soft steel sheet. The weld overlay provides the hard erosion resistant surface, while the soft carbon steel backing enables the material to be cut, shaped, and welded onto the fan blades.

 The mild-steel base plate makes it possible to remove the wear plate from the Blower if necessary, but this requires skilled work with a gas torch. Most Blower wheels are built with regular carbon steel plate (20-25,000 psi yield strength), and present little problem. However, a Blower built with high-strength structural steel such as SSSIOO (about 100,000 psi) should be treated with care to avoid degrading its structural integrity. It is always possible to add more weld overlay onto the Mild Steel base plate, provided the erosive wear has not progressed through to the structural material.

 Note that the weld overlay is not intended to provide any structural strength to the Blower and may actually be cracked when delivered from the manufacturer. This cracking is due to the Flame or plasma-sprayed metalizing of a Blower wheel is frowned on by most manufacturers because of the thinness of the protective layer and because it can peel off if not correctly applied. However, if the wheel surface is properly prepared beforehand, and the sprayed coating is regularly inspected, this may be a viable method of extending fan life. But it should be understood that spray coatings involve a certain amount of alloying with the base material and may interfere with future fan elements.

 Ceramic or tungsten carbide tiles are receiving considerable attention because of their extreme hardness, but their big problem is secure attachment and cost. Ceramic tiles have been successfully applied to flat Radial Blower Impellers and are excellent for Housing linings, but epoxy grouting methods limit operating temperatures.