Schlagel, Inc.

- Conveyor



The following information is provided as a guide to assist the designer in evaluating the operating characteristics and drive requirements for various conveying applications. It is not intended to provide overall engineering for those not thoroughly familiar with the basic of en masse conveying. We recommend that all design criteria be presented to factory engineers for evaluation and recommendations.

Conveying Speeds
In general, the maximum recommended chain speed is 180 FPM. Total conveyor life increases rapidly as this speed is reduced. Severe duty service conveyors should be limited to approximately 120 FPM or less.

When flood feeding (see Figure 1) the capacity is exactly that of the design tables shown here. In this condition the conveyor is 100% full and capacity is adjusted by regulating the conveyor speed.

When the input is controlled (see Figure 2) the conveyor should be run at 105% of the maximum capacity that can be input. This will assure enough capacity within the conveyor housing to eliminate the possibility of material backup or plugging.


There are many factors that must be considered when determining horsepower requirements. The formula shown here represents a compromise of these factors to allow a close approximation. In most cases, this figure will be greater than the horsepower actually required. When conveying higher friction materials such as soybean, formula (1) should be used.

1.) HP = (BPH x Length)/56000

When conveying corn or most of the small grains formula (2) should be used.

2.) HP = (BPH x Length)/75000

If inclines are involved additional horsepower must be added. Formula (3) estimates this.

3.) HP = (BPH x E)/30000

Where E = Elevation in feet              HE = Additional HP required

Add this figure to that obtained with formula (1) or (2).

Maximum Lengths
The maximum length of a Powerflow Conveyor is limited by the pull required on the conveying chain. This is a function of the material weight per foot of conveyor, the friction factor of the material, breaking load of the chain, safety factors and chain wear. Acceptable chain life is often the most important factor.
The figures shown in Table 1, see page 101, serve as guidelines for maximum lengths. The shorter value shown is for the higher friction and or weight material such as soybean. The longer value can be used with materials like corn or wheat. It is possible to increase these lengths if chain speed or service requirements are reduced.

Material flowability determines the maximum incline at which a conveyor may be operated. When the incline exceeds 4 degrees (7/8 inch rise per foot of run) chain modifications may have to be considered. These modifications can increase the inclinability to 9 degrees or more.

Inlets usually consist of a simple housing above the conveyor. Care must be taken to keep the inlet well in front of the tail sprocket. Long hoppered inlets from dump pits etc., will consume additional horsepower. Factory engineering is available to help you with this special hopper design and horsepower requirement.
If you intend to feed the conveyor from more than one inlet at a time, then you must make certain that the conveyor is not running full after the last inlet. Consult the factory for further information on this.

Most installations use shaft mounted drives because of their reliability and efficiency. Gear and roller chain drives may be used but access to the head section cover and a rigid mechanical connection between the head and drive platform must be provided. We can furnish drives of any configuration to suit your installation.

Example Requirements
A conveyor 160 feet long to convey 14,000 BPH of soybean and corn is required. It is to be fed from a 14,000 BPH leg and it will be placed on an incline with the discharge end 7 feet higher than the inlet.

Conveyor Size
Referring to Table 1, page 101, it is found that Model 1618 is the smallest conveyor that will handle 14,000 BPH. Because soybean will be conveyed, the shorter value listed under “Maximum Length” (153 feet) must be used. Since 160 feet is required, Model 1620 will be selected as all of the parameters fall within the requirements set forth in our example.

Check Incline
Within the discharge elevated 7 feet above the inlet, it will be necessary to check the incline to see if it exceeds the 4 degree maximum angle or 7/8 inch rise per foot of run. This can be accomplished by multiplying the elevation (7 feet) by 12 and dividing by the overall length (160 feet) The answer is (.53 inches “rise per foot of run” is well below the maximum incline. If the angle had been greater than 4 degrees, a chain modification may have been necessary. In that case the factory should be contacted for assistance.

Compute Horsepower
Since soybean will be conveyed formula (1) will be used.

1.) (14000 x 160)/56000 = 40 HP

The incline will require additional horsepower as computed with formula (3).

3.) (14000 x 7)/30000 = 3.27 HP

If inclines are involved additional horsepower must be added. Formula (3) estimates this.

2.) HP = (BPH x Length)/75000

The horsepower required is therefore
40 + 3.27 = 43.27 HP
Select a 50 HP Motor and Drive.

Chain Speed and RPM
Table 1 shows that a Model 1620 delivers 82.67 BPH for each FPM of chain speed. Divide 14000 by 82.67 to obtain chain speed.

14000/82.67 = 169.3 FPM

Using the same table, it is found that Model 1620 delivers 330.7 BPH for each RPM of the drive shaft. Divide 14000 by 330.7 to obtain RPM.

14000/330.7 = 42.3 RPM

Because the bucket elevator will provide a controlled feed of up to 14,000 BPH, the conveyor should be run at 105% of the computed speed.

169.3 x 1.05 = 177.8 actual FPM
42.3 x 1.05 = 44.4 actual RPM

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