Page 97 - banneredTapco Catalog

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computing 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 fgure the capacity of a bucket elevator you must frst 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 fll)

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 _________ = _________

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 _________ = _________

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 _________ = _________

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 _________ = _________

60

2,150

1.10

60

1,728

1.10

2,000

1.10

2,204.62

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.

p

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