Posted on Wednesday Mar 13, 2019 at 04:19AM in Belting & Conveyors
Bucket Elevator Selection
The following factors should be considered when selecting a bucket elevator.
1.) Type and characteristics of material being handled:
2.) Abrasive, free-flowing, sluggish, temperature, fluffy, friable, subject to degradation etc.
3.) Weight of material in pounds per cubic foot.
4.) Maximum rate in tons, bushels or cubic feet per hour.
5.) Maximum size and percentage of lumps, along with average size of material.
6.) Operating conditions: indoors, outdoors, corrosive, contamination, etc.
7.) Service required: continuous or intermittent.
Common Types of Bucket Elevators
Centrifugal Discharge Elevators
Elevators of this design are predominate in the bulk handling of free-flowing, fine, and loose materials with small to medium size lumps. They are generally selected when there is a need to move large amounts of material quickly. Instead of direct loading, the buckets serve as the loading apparatus, scooping material up from the boot/inlet section. For this reason, durable buckets should be selected with this design. Centrifugal force at the head pulley “throws” material into the discharge chute. The buckets are spaced in wider intervals to prevent discharge interference from the preceding bucket and to assure maximum fill of the buckets at the boot end (inlet) while moving at a higher speed. The design of this style yields optimized material fill and reduced interference between buckets. They can be supplied with belt or chain depending on the material be handled.
Continuous Discharge Elevators
Continuous elevators are designed to handle friable, fragile materials to minimize product degradation, or damage. They are also ideal for handling sluggish or abrasive materials. They are used to convey light, free-flowing material where aeration of the material must be avoided. Material is fed directly into the bucket from the inlet chute. The buckets are designed for gentle discharge, the buckets are closely spaced on the belt or chain to allow the material to flow over the backside of the preceding bucket, whose extended sides form a chute to guide the material into the discharge spout. Direct loading of the material combined with the slow speed of this elevator avoids the “throwing” action associated with centrifugal style elevators. Making it ideal for use with fragile materials. This style elevator can also be supplied with belt or chain.
Positive discharge elevators operate efficiently at low bucket speeds and are suitable for handling light, fluffy and fragile materials and those having a tendency to stick in the buckets. The buckets are mounted at spaced intervals, are loaded by scooping up material from the boot or by feeding the material directly into them. After passing over the head wheel, the buckets are inverted over the discharge spout, thus providing a positive discharge of material. Normally, the buckets are malleable iron mounted at intervals on double strands of chain.