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www.tapcoinc.comcomputing bucket elevator capacity
Note:
Traditional formulas for computing elevator capacity are based on the bucket manufacturer’s published gross bucket capacity. Tapco recommends using water
level bucket capacities because published gross capacities are inaccurate and irrelevant. Tapco can provide the water level capacity for any size and brand of bucket.
To figure the capacity of a bucket elevator you must first know the following:
1.
CAPACITY
of the bucket at water level (cubic inches).
4.
SPEED
of the belt or chain (feet per minute). See formula below.
2.
SPACING
of the buckets on the belt or chain (centers).
5.
PRODUCT WEIGHT
per cubic foot (only if answer is desired in tons or metric tons).
3.
NUMBER OF ROWS
of buckets on the belt or chain.
Then proceed as follows: Multiply the capacity of the bucket times the spacing multiplier in the table below times the number of rows of buckets. This will give the ca-
pacity in cubic inches of each running foot of the belt or chain. Multiply this times the speed of the belt or chain for the capacity discharged per minute. Then multiply
by 60 to get the capacity discharged per hour. The answer will be in cubic inches.
Convert as follows:
BUSHELS
- Divide by 2,150 to convert bushels.
CUBIC FEET
- Divide by 1,728 to convert to cubic feet.
TONS
- Multiply cubic feet capacity times weight of product per cubic foot and divide by 2,000.
METRIC TONS
- Multiply cubic feet capacity times weight of product per cubic foot and divide by 2,204.62.
You now have the water level capacity of the elevator. Actual capacity would range from 10% to 20% above water level. For engineering purposes, Tapco recommends
using 10% above water level capacity. Greater capacity may be realized in the elevator, however, this is dependent on several factors besides the buckets: head and boot
design, loading and discharge, angle of repose of the product, etc..
CAPACITY FORMULAS (Based on water level bucket fill)
For BUSHELS per hour:
capacity
bu./hr.
+10%
of bucket
spacing
number
speed
water
actual
bu./hr.
water level
multiplier
of rows
feet/min.
min./hr.
cu. in./bu.
level
capacity
actual
_________ x _________ x _________ x _________ x _________ ÷ _________ = _________ x _________ = _________
_________ x _________ x _________ x _________ x _________ ÷ _________ = _________ x _________ = _________
_________ x _________ x _________ x _________ x _________ ÷ _________ = _________ x _________ = _________
_________ x _________ x _________ x _________ x _________ ÷ _________ = _________ x _________ = _________
For CUBIC FEET per hour:
capacity
cu. ft./hr.
+10%
of bucket
spacing
number
speed
water
actual
cu. ft./hr.
water level
multiplier
of rows
feet/min.
min./hr.
cu. in./cu. ft.
level
capacity
actual
_________ x _________ x _________ x _________ x _________ ÷ _________ = _________ x _________ = _________
_________ x _________ x _________ x _________ x _________ ÷ _________ = _________ x _________ = _________
_________ x _________ x _________ x _________ x _________ ÷ _________ = _________ x _________ = _________
_________ x _________ x _________ x _________ x _________ ÷ _________ = _________ x _________ = _________
For TONS per hour: First determine cubic feet/hr. at water level using above formula then proceed as follows:
product
+10%
cu. ft./hr.
weight
tons/hr.
actual
tons/hr.
water level
per cu. ft.(lbs.)
lbs./ton
water level
capacity
actual
_________ x _________ ÷ _________ = _________ x _________ = _________
_________ x _________ ÷ _________ = _________ x _________ = _________
_________ x _________ ÷ _________ = _________ x _________ = _________
For METRIC TONS per hour: First determine cubic feet/hr. at water level using above formula then proceed as follows:
product
lbs.
metric
+10%
metric
cu. ft./hr.
weight
metric
tons/hr.
actual
tons/hr.
water level
per cu. ft.(lbs.)
tons
water level
capacity
actual
_________ x _________ ÷ _________ = _________ x _________ = _________
_________ x _________ ÷ _________ = _________ x _________ = _________
_________ x _________ ÷ _________ = _________ x _________ = _________
60
60
60
60
2,150
2,150
2,150
2,150
1.10
1.10
1.10
1.10
60
60
60
60
1,728
1,728
1,728
1,728
1.10
1.10
1.10
1.10
2,000
2,000
2,000
1.10
1.10
1.10
2,204.62
2,204.62
2,204.62
1.10
1.10
1.10
3
1
⁄
2
" 4" 4
1
⁄
2
" 5" 5
1
⁄
2
" 6" 6
1
⁄
2
" 7" 7
1
⁄
2
" 8"
3.43 3.00 2.67 2.40 2.18 2.00 1.85 1.71 1.60 1.50
8
1
⁄
2
" 9" 9
1
⁄
2
" 10" 10
1
⁄
2
" 11" 11
1
⁄
2
" 12" 13" 14" 15" 16" 17" 18"
1.41 1.33 1.26 1.20 1.14 1.09 1.04 1.00 .92 .86 .80 .75 .71 .67
FEET PER MINUTE FORMULA: Belt or chain speed can be determined if the head pulley or sprocket diameter and R.P.M. of the head shaft is known.
π
head pulley dia./in.
RPM
in./ft.
feet/min.
______________ x ______________ x ______________ ÷ ______________ = ______________
SPEED RANGE FOR TAPCO BUCKETS - Contact Tapco Inc. for engineering recommendations on either new or existing elevators.
3.1416
12
Multiplier
SPACING multipliers: For determining number of buckets per foot of belt or chain. Below multipliers are calculated by dividing one foot (12") by the bucket spacing dimension in inches.
Bucket Spacing on
belt or chain