Calculating Required Horsepower For a Horizontal Drag Conveyor

Calculating Required Horsepower For a Horizontal Drag Conveyor (En-Masse Conveyor):
There are several ways to calculate horsepower for a drag chain conveyor in a grain handling application, however, I have found this shortcut for figuring horsepower for a horizontal drag conveyor to be one of the easiest to use.
1.  Determine overall length of drag conveyor
2. Multiply LENGTH X BUSHELS PER HOUR
3.  Divide results by 55,000

The above formula has been found to be adequate for products such as shelled corn and soybeans.  HEAVIER PRODUCTS MAY REQUIRE ADDITIONAL HORSEPOWER.

Example:
50 foot overall length conveyor handling corn at 10,000 bushels per hour.
50 x 10,000 = 500,000
500,000 divided by 55,000 = 9.0909
Round up to nearest motor size means you would use a 10 horsepower electric motor.

Calculating Horsepower for a Bucket Elevator

HORSEPOWER FORMULA FOR BUCKET ELEVATORS:

1. DISCHARGE HEIGHT IN FEET X BUSHELS PER HOUR,

Divided by 33,000 gives BARE HORSEPOWER

2. Multiply Bare Horsepower x 1.25 (safety factor) to get DESIGN

HORSEPOWER.

3. This calculation is based on grain weighing 60# per bushel.

ALTERNATE HORSEPOWER FORMULA:

1. Multiply DISCHARGE HEIGHT IN FEET X POUNDS OF MATERIAL

RAISED IN 1 MINUTE. Divided by 33,000 gives BARE HORSEPOWER.

2. Multiply Bare Horsepower by 1.25 (Safety Factor) for DESIGN

HORSEPOWER.

Calculate Bucket Elevator Capacity

TO FIND BUCKET ELEVATOR LEG CAPACITY:

1. DETERMINE BELT SPEED IN FEET PER MINUTE

a. Motor RPM x motor pulley diameter, divided by driven pulley diameter = Input shaft speed to drive.

b. Divide Input shaft speed by Drive reduction ratio (15:1, 25:1, etc.) This gives the head shaft RPM.

c. Multiply the head shaft RPM x head pulley diameter in feet, x

3.1416. This gives the Belt speed in feet per minute.

2. FIND THE NUMBER OF CUPS FILLED IN ONE MINUTE:

a. Multiply feet per minute of belt speed x 12”, divided by cup spacing in inches.

b. Find cup capacity from Manufacturer’s chart in cubic feet.

Use water level + 10% or 75% of gross cup capacity.

c. Multiply cups filled per minute x cup capacity in cubic ft. This gives capacity of leg in one minute. Multiply result x 60 minutes

for hourly capacity in cubic feet.

d. For Bushels per hour, multiply cubic ft. per hour x .8

Calculating Grain Bunker Volume and Capacity

Following is an illustration that can assist you in determining how many bushels of grain will fit in a grain bunker or planned flat storage grain area.  Note: All volume is in cubic feet.  All capacities are in bushels.

Calculating Bucket Elevator Spout Length

Dry grain typically flows in a spout at an angle of 45° or more.  High moisture grain, sunflowers and ground feed generally require spouts at a minimum angle of 60°.  To calculate spout length, the following calculations apply:

Elevator Leg Spout Capacities

When determining the required diameter of spouting, consider the following: Material flow characteristics, moisture content, cleanliness of material (no trash), spouting angle, speed of material entering the spout, possible bottlenecks created by distributors, elbows or other devices in the system.

'*Note: The above information should be used as a guideline suggestion only.  No liability is assumed for its use. All considerations mentioned above will alter spout capacity and must be allowed for. Spouting for ground feed and other fluffy materials should not be set at less than 50 degrees. Some of these materials have unusual characteristics. Spouting for almost all materials should be vented if the spout angle is 55 degrees or more.

Hydraulic Motor Size vs. RPM Calculation:

Some useful formulas are listed below for figuring out how to size a hydraulic motor for your auger or other grain handling equipment.

                Gallons per minute of supply x 231
RPM =   Cubic inches of motor displacement

                                 Gallons per minute x 231
Motor cubic inches =              RPM

                            RPM x cubic inches of motor displacement
GPM required =                          231


PTO Shaft
A common question is, "How long can I expect my PTO shaft to last?"  While there are many factors that contribute to that answer, there are a few rules of thumb that should be kept in mind.

Grease! Grease! Did I mention grease?  The more often the better.  The number one thing you can do to extend the life of your PTO shaft is to grease it often.  Want to make sure it gets done?  Hang a grease gun on the equipment with a PTO shaft.

Some information regarding how operating angle contributes to the life expectancy of a PTO shaft:
At 540 RPM and transmitting 40 HP, a category 4 PTO shaft at 22 degrees has a 12% decrease in life expectancy when the angle is changed by 3 degrees.
At 540 RPM and transmitting 24 HP, a category 3 PTO shaft at 22 degrees has a 22% decrease in life expectancy when the angle is changed by 6 degrees.