Impeller

FIGURE 70 A sleeve for pumps with an overhung impeller

SLEEVE SHAFT NUT

FIGURE 71 A seal arrangement for the shaft sleeve to prevent leakage along the shaft

SLEEVE SHAFT NUT

FIGURE 71 A seal arrangement for the shaft sleeve to prevent leakage along the shaft

ferred. For pumps subject to abrasives, hardened chrome or other stainless steels give good results. In most applications, a hardened chromium steel sleeve will be technically adequate, and the most economical choice. For severe or unusual conditions, coated sleeves are used. Ceramic coatings, applied using a plasma spray process, have also been used. Chromium oxide and aluminum oxide are the most common ceramic coatings. Both are extremely hard and resist abrasive wear well.

Ceramic coatings have been replaced in some applications by tungsten carbide coatings applied using a high-velocity oxyfuel (HVOF) process. The superior impact resistance and bond strength of these coatings is well documented. Another coating that is widely used on pump sleeves is a nickel-chromium-silicon-boron self-fluxing coating. This coating has a good resistance to galling and moderate resistance to abrasive wear.

Sleeves intended for coating should be machined with an undercut, so that the coating does not extend to the edge of the sleeve. This will prevent chipping at the edge, especially with the more brittle ceramic coatings.

Renewable Energy 101

Renewable Energy 101

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.

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