Bucket Elevators
Bucket Elevators are designed to lift material vertically and are, by far, the least expensive option
for elevating bulk materials. There are two basic styles; Centrifugal Discharge and Continuous
Discharge; either of which can have buckets mounted on a belt or a chain. (Please see “Bucket Elevator Types” in the down loads section for more illustration.)
Centrifugal Discharge units have buckets mounted at wide intervals and are designed to dig or scoop
dry, granular, free flowing materials that are smaller than 1 1/2” in size (maximum lump size
varies by bucket size).from the boot, or the bottom of the casing. They operate at higher speeds, which
will throw the material from the bucket as it comes over the head pulley (or sprocket) due to
centrifugal force and are capable of handling up to 15,000 cubic feet per hour. (Common bucket sizes
are 6x4, 8x5, 10x6, 12x7, 14x7, 16x8, 18x8, 18x10 and 20x10.)
A sub-style of Centrifugal Discharge elevators is called a “Cement Mill” unit; it
utilizes style “AC” style buckets, which are designed to handle the dry, fine, free-flowing
materials that are typically found in a cement plant application. Cement Mill elevators are usually
chain mounted and can handle up 15,000 cubic feet per hour with standard “AC” buckets and
12,000 cubic feet per hour “ACS” style (saddlebag) buckets. (Common bucket sizes are: 12x8,
16x8, 18x10, 20x10, 24x10 and 27x12.)
Continuous Discharge units have buckets spaced very closely together and are designed to handle
larger lump sizes or materials that are easily broken. Therefore, they generally do NOT dig or scoop
material, but rather the material is loaded directly into the buckets. They operate at much lower
speeds, allowing the material to gently slide from the buckets, rather than be thrown. They can deliver
up to 25,000 cubic feet per hour. (Common bucket sizes are: 8x5, 10x5, 10x6, 10x7, 12x6, 12x7, 12x8,
14x8, 16x8, 18x8, 18x10, 20x12 and 24x12.)
A variation on the Continuous Delivery bucket elevator is the “Super Capacity” style,
which has larger buckets mounted between two strands of chain. This configuration can handle 15,000
cubic feet per hour, or more. (Common bucket sizes are 12x8, 14x8, 16x8, 16x12, 20x8, 20x12, 24x12,
30x12 and 36x12.)
Bucket Elevators are highly efficient and have the added benefit of being dust-tight and
weather-tight. They also lend themselves to harsh applications, such as; highly abrasive materials,
corrosive materials, elevated temperatures and potentially explosive materials.
As an alternative to bucket elevators, a Vertical Screw Elevator (VSE) is an option for a fairly
small capacity with not much lift needed. They actually take up the least amount of floor space, but
require quite a bit more power and are not nearly as self-cleaning as a bucket elevator. (Common sizes
are 6”, 9” 12” and 16”.)
Elevator Buckets can be belt mounted or chain mounted. Here are some of the differences:
Belt Mounted Elevators
- Less costly
- Quieter
- Smooth running
- More Corrosion resistant
- Lighter hanging weight means a smaller head shaft and bearings
- More wear resistance in highly abrasive applications
- More likely to slip if not properly tensioned or lagging is worn or wet
- More difficult to splice or remove excessive belting
- Bucket bolts more likely to pull out
- Less tolerant of boot flooding
- Complete Belt is harder to install
- Bucket spacing significantly more flexible
Chain Mounted Elevators
- More costly
- More Noise
- Tend to vibrate and “clank”
- Stronger
- Higher hanging weight means a larger head shaft and bearings
- Higher material and ambient temperature tolerance
- Positive engagement w/ no slippage (traction wheels subject to slippage)
- Easy to remove excessive chain links
- Bucket bolts unlikely to pull out
- More tolerant of boot flooding
- Complete chain easier to install
- Bucket spacing must match chain pitch multiples
TPI Engineered Systems is based in Atlanta, Georgia; serving as the premier designer, engineer,
manufacturer, and installer of custom bulk materials conveyor systems all across the United States. For
more information on any of the TPI Systems, call 804-232-4580 to speak to one of our knowledgeable and
highly experienced employees.
