Selection of bearing material for an intermediate hanger is based on experience, together with a consideration of the characteristics of the material to be conveyed. Normally, the bearing selection will be made from one of the following three bearing types:
A. Babbitted or Bronze Bearings
Lubricated babbitted bearings are very frequently used, but have a maximum operating temperature of 130° F; lubricated bronze bearings may be operated at temperatures up to 225° F. This temperature figure for bronze bearings may be exceeded by the use of appropriate high temperature lubricants. CARE MUST BE EXERCISED IN THE USE OF BABBITTED OR BRONZE BEARINGS WHEN THE CONVEYED MATERIAL MUST NOT BE CONTAMINATED BY THE PRODUCTS OR BEARING WEAR OR THE LUBRICANTS USED.
B. Self Lubricated Bearings
Self lubricated bearings are available in several types.
1. Oil impregnated hard maple wood has a maximum operating temperature of 160° F.
2. Oil impregnated sintered bronze has a maximum operating temperature of 200° F.
3. Plastic and reinforced fibre compounds are available in a wide variety of compositions and constructions, and can be obtained from many sources. They require no grease or oil lubrication and are usually run dry. They are best suited for use in conveyors wetted with water. Maximum operating temperatures vary with the composition and construction of the bearing. When appropriately used, the wear rate is usually low.
C. Ball Bearings
Ball bearings are preferably used when handling granular or pelletized materials not containing any fine powder. Maximum operating temperature is 225° F with petroleum based lubricants, or 270° F with high temperature synthetic lubricants. When appropriately used and sealed against loss of lubricant, ball bearings usually involve no contamination of the material conveyed.
No comments:
Post a Comment