power requirements for augering fertilizer and … · power requirements for augering fertilizer...

POWER REQUIREMENTS FOR AUGERING

FERTILIZER AND THE EFFECT OF AUGERING

ON FERTILIZER PULVERIZATIONby

E. H. WiensMember C.S.A.E.

Agricultural Engineering DepartmentUniversity of SaskatchewanSaskatoon, Saskatchewan

time and from the truck into the fertilizer attachment on the seeder orthe broadcast fertilizer spreader.

The objective of this study was todetermine:

1. The power requirements foraugering fertilizer.

2. The tendency for the fertilizerto plug the auger.

3. The degree of pulverization ofthe fertilizer due to augering.

4. The effect of fertilizer pulverization on the distribution pattern produced by a broadcastfertilizer spreader.

PROCEDURE

Throughput and power requirements to convey wheat, 11-48-0,33.5-0-0, 23-23-0 and 46-0-0 fertilizers,with a 6-inch diameter auger, atvarious angles of inclination, weremeasured.

The effect of augering on fertilizerpulverization was evaluated byspreading 33.5-0-0 and 27-14-0 fertilizers, which had been subjected toa different number of augerings,using a broadcast fertilizer spreader.

Sieve Analysis

The amount of fertilizer pulverization due to augering was determinedby performing a sieve analysis offertilizer samples. Representative 250gram samples were obtained using asample divider. The samples werethen placed in a stack of Tyler Canadian Standard Sieves, consisting ofseries numbers as shown in Tables3 to 6, and vibrated for five minuteson a Syntron Shaker which was setat 90 volts.

The series of sieves listed in Tables3 and 4 were so chosen that the sieveopenings represented a geometric

HYDRAULIC MOTOR

R.P.M. AND TORQUE

METER.

INTRODUCTION

The application of fertilizer on theprairie grain farm is accomplished intwo ways.

1. Phosphate fertilizers (11-48-0and 11-55-0) and low analysisnitrogen fertilizers (27-14-0 and23-23-0), up to approximately 25lbs. of nitrogen per acre, areapplied with the seed using afertilizer attachment on theseeder. Nitrogen in excess of 25lbs. per acre may cause germination damage if applied withthe seed (2). The 27-14-0 and23-23-0 fertilizers, if used at highrates, could be applied with abroadcast spreader.

2. High analysis nitrogen fertilizers(33.5-0-0 and 46-0-0) are applied as surface applicationseither in the fall or in the springprior to seeding, using a broadcast fertilizer spreader.

With the increased use of fertilizer,consumers are adopting bulk handling methods. The movement of fertilizer in bulk form, from dealer tofarmer, may be accomplished in oneof the following ways.

1. The dealer or manufacturer maydeliver the fertilizer to the farmand put it into the fanner's storage bin using pneumatic means.

2. The farmer may haul his ownfertilizer from the dealer. Thefertilizer at the dealer's facilityis loaded onto the farmer's truckeither from a hopper bottomedbin or by means of a belt conveyor.

In the case of the latter approach,it is possible for the fertilizer to besubjected to three augerings. It couldbe augered from the truck into thefarmer's storage bin, from the storagebin back onto the truck at seeding Figure 1. Test auger.

CANADIAN AGRICULTURAL ENGINEERING, VOL. 11, No. 1, MAY 196923

progression. The series used in Tables5 and 6 follow no set pattern orstandard but were chosen to give arepresentative analysis of the particlesizes encountered.

EQUIPMENT

The auger used for the tests wasa 10-foot long, 6-inch-diameter augerwith dimensions as shown in figure 1.A hydraulic motor was used to drivethe auger. A torque and rpm meter(3) was installed between the hydraulic motor and auger. The outputfrom the meter was recorded on aBrush Oscillograph. Simultaneously,the throughput was obtained from arecording on the Brush Oscillographproduced by the output from a transducer. The output voltage from thetransducer was proportional to thecumulative weight of the fertilizerdelivered by the auger for the sametime period that torque and rpmwere measured. Throughput inpounds per minute was calculatedfrom the slope of the recordedstraight line relating cumulativeweight and time. Values of torquewere obtained at various throughputs, speeds and angles of inclinationof the auger to the horizontal.Throughput was varied by varyingthe speed of the auger.

The broadcast fertilizer spreaderused to determine the effect of pulverization on the distribution patternwas equipped with two spinnerswhich were driven by the tractorpower take-off. The effect of spreaderadjustment on the distribution pattern had been established by previoustests (4).

OBSERVATIONS AND RESULTS

Power Requirements

Information on horsepower requirements for conveying grain at variousangles of inclination and throughputare available in the Agricultural Materials HandHng Manual (1). Material characteristics such as bulkdensity, particle size and angle ofrepose are factors which determinethe power required to convey them.

The bulk density of most fertilizersis greater than that of grain andthus the power requirements to convey the two materials differ. Bulkdensities of fertihzer vary, dependingon the manufacturer. Shown in Table1 are some nominal bulk densities offertilizers compared to the bulk den-

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TABLE I. BULK DENSITIES

Fertilizers

11-48-0

27-14-0

33. 5-0-0

46-0-0

59 lbs/ft. 3

60 lbs/ft. 3

56 lbs/ft. 3

46 lbs/ft. 3

Grain

Wheat

Barley

Oats

Flax

47 lbs/ft. 3

37 lbs/ft.

27 lbs/ft.

44 lbs/ft.

TABLE II. POWER REQUIREMENTS FOR A 6-INCH DIAMETER, 10-FOOTLONG AUGER AT AN ANGLE OF INCLINATION OF 60° AND A THROUGHPUTOF 800 LBS./MIN.

Percent IncreaseMaterial Augered Horsepower Over Wheat

Wheat 1. 7--

11-48-0 2. 7 59%

23-23-0 2. 2 30%

33.5-0-0 2. 0 18%

46-0-0 2.0 18%

sity of selected grains. The bulk densities of the fertilizers were suppliedby a fertilizer manufacturer and thebulk densities of the grains are basedon the prescribed bushel weights ofthe grains (2).

Figures 2 to 6 show horsepowerand speed versus throughput forwheat and four different anlyses offertilizers at various angles of inclination of the auger to the horizontal.In general, more horsepower was required to convey fertilizer thanwheat. However, in the case of33.5-0-0 and 46-0-0 at an angle ofinclination of 30°, the power requirement was approximately the same.

Table 2 shows a typical comparison of the power required to conveythe different materials at the throughput and angle of inclination shown.Also, the percent increase in horsepower required to convey fertilizersas compared to wheat is given. It wasnoted that after the fertilizer becamepulverized (augered 20 to 30 times)more power was required to conveyit.

Plugging

One of the problems encounteredduring the test was plugging or stoppage of the auger. Plugging occurredif the auger was not emptied of fertilizer after use and if the intake wasleft buried. The fertilizer, in thiscase, accumulated in the lower section of the auger tube and formed acompacted core. Plugging was moresevere and occurred more rapidly asthe angle of inclination of the augerto the horizontal was increased. Itwas also observed that the augertended to plug more readily withpulverized fertilizer. To free theauger after plugging occurred, theburied end had to be exposed, allowing the compacted fertilizer to runout. Thus, to insure trouble-freeauger performance when conveyingfertihzer, it would be advisable toempty the auger before allowing it tostand idle.

If the auger was left idle for onlya short time (10 to 15 minutes), plugging did not occur since the fertilizerdid not have time to compact at the


SPEED ----

/30° sy™> --

/ y/ /

//45° y //45- -/ s y//67 y / /

1/ y y y„cfy y y 67

" / yyy y

'}/ y/ AUGER SPECIFICATIONS

' , / Exposed Flighting— 12"

15 2 0 2 5 30

| HORSEPOWER300 400 500 600

SPEED -rpm

Figure 2. Speed and horsepower vs. throughput while conveying wheat at three anglesof inclination.

bottom of the tube. But even in thiscase the starting torque required wasat least double the actual runningtorque required for normal operation.Compaction of the fertihzer occursmore rapidly and is more severe ifthe full auger is in a truck bouncingover rough terrain.

Pulverization

Pulverization of fertilizer is dependent upon the moisture contentof the fertihzer. If the fertilizer isdry, pulverization is increased. Pulverization was also found to varywith the analysis of the fertilizer. Differences in the degree of pulverization were even noted among the sameanalysis of fertihzer, produced bydifferent manufacturers.

The nitrogen fertilizers (27-14-0and 33.5-0-0) pulverized more readilythan did the phosphate fertilizers(11-48-0). A comparison of the breakup after continued augering, between27-14-0 and 11-48-0 is shown inTables 3 and 4. As an arbitrary figurefor comparison the percentage of material passing the Tyler CanadianStandard Sieve Series Number 16was chosen. As can be seen by comparing Tables 3 and 4 the 27-14-0pulverized to a greater degree thanthe 11-48-0.

There has been some concern expressed that pulverization of fertilizer due to augering would affectthe distribution pattern produced bya broadcast fertilizer spreader. To determine the effect of pulverization onthe distribution pattern, a fertihzerspreader was adjusted to give thebest distribution pattern establishedin previous tests (4). A 27-14-0 fertilizer was then used to determinethe distribution pattern obtained with

I 5 2 0 2.5

i HORSEPOWER

300 400 500

SPEED - r p

Figure 3. Speed and horsepower vs. throughput while conveying 11-48-0 fertilizer atfour angles of inclination.

I 800

/'"-

AUGER SPECIFICATIONS

Length 10'

Exposed Flighting -I I

5 20 2 5 30 3 5

HORSEPOWER

300 400 500 600 700

SPEED -rpm

Figure 5. Speed and horsepower vs. throughput while conveying 33.5-0-0 fertilizer atthree angles of inclination.

DISTANCE FROM CENTERUNE

Figure 7. Distribution pattern obtained whilespreading 27-14-0 fertilizer that was notpreviously conveyed by an auger.

fertilizer which had not been augeredand augered 10 times. The 27-14-0fertihzer is composed of a blend of11-48-0 and 33.5-0-0 fertilizer particles. Since the 33.5-0-0 particlespulverize more readily than do the11-48-0 particles, it was thought thatparticle separation may occur duringbroadcast spreading and thus affect

CANADIAN AGRICULTURAL ENGINEERING, VOL. 11, No. 1, MAY 19*9

AUGER SPECIFICATIONS

_1_Exposed Flighting -

15 2 0 2 5 30 35

| HORSEPOWER | |300 400 500 600 700

SPEED -rpm

Figure 4. Speed and horsepower vs. throughput while conveying 23-23-0 fertilizer atfour angles of inclination.

, 30°

45^

60_^

— — AUGER SPECIFICATIONSLengthDiameter

Exposed Flighting -

20 25

| HORSEPOWER

300 400 500 600 700

SPEED- rpm

I

30 35

Figure 6. Speed and horsepower vs. throughput while conveying 46-0-0 fertilizer atthree angles of inclination.

DISTANCE FROM CENTERLiNE

Figure 8. Distribution pattern obtained whilespreading 27-14-0 fertilizer that was augered 10 times through a 10-foot long, 6-inch-diameter auger at a 45° angle of inclination and a speed of 600 rpm.

the distribution pattern. The resulting distribution patterns are shownin figures 7 and 8. No appreciabledifference in the distribution patternresulted and the mean applicationrate remained unchanged. Sieveanalysis of the fertilizer (table 5) indicated that very little pulverizationoccurred.

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DISTANCE FROM CENTERLINE

Figure 9. Distribution pattern obtained whilespreading 33.5-0-0 fertilizer that was notpreviously conveyed by an auger.

DISTANCE FROM CENTERLINE - feet

Figure 10. Distribution pattern obtainedwhile spreading 33.5-0-0 fertilizer that wasaugered five times through a 10-foot long,6-inch-diameter auger at a 45° angle of inclination and a speed of 600 rpm.

Distribution patterns were similarly obtained for a 33.5-0-0 fertihzerthat had not been previously augered(figure 9) and augered 5 times(figure 10). There was no noticeablechange in the distribution patternsand the sieve analysis (table 6)showed little pulverization due toaugering.

Fertilizer, on the farm, would notnormally be augered more than threetimes. Thus, it can be said that undernormal conditions, pulverization dueto augering will be negligible and hasvery little effect on the application ofthe fertilizer.

CONCLUSIONS

Conveying fertilizer with an augerrequires more power than is requiredfor conveying wheat.

If a full auger is left idle with theend buried in fertilizer, plugging willoccur, necessitating the freeing of theburied end and emptying of the

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TABLE III. PULVERIZATION OF 27-14-0 FERTILIZERTyler

Canadian

Standard

Sieve Series

No.

4

8

16

30

50

100

Pan

% of Material

Passingi No. 16 Sieve

Percent of Material Retained on Sieves

Unaugered

0

9. 6

84. 8

5.. 2

0. 4

5. 6

Augered 4 Times

0

8. 6

85. 4

5. 4

0. 4

0. 2

6. 0

Augered 40 Times

0

6.4

69. Z

19. 4

Z. 6

1. 0

1. 4

24. 4

TABLE IV. PULVERIZATION OF 11-48-0 FERTILIZERTyler

Canadian

Standard

Sieve Series

No.


Unaugered Augered 6 Times Augered 26 Times Augered 60Times

4

8

16

30

50

100

Pan

0

8. 4

91. 2

0

6. 2

91. 2

0

4. 8

90. 4

0

5. 0

86. 8

0. 4 2. 4

0. 2

4. 6

0. 2

6. 8

0.8

0. 4

0. 2

% of Material

PassingNo. 16 Sieve 0. 4 2. 6 4. 8 8. 2

TABLE V. SIEVE ANALYSIS OF 27-14-0 FERTILIZER*

Tyler

Canadian Standard

Sieve Series


Unaugered Augered 10 TimesNo.

8 12. 0 12. 0

10 34.0 33.0

14 48.0 43.0

16 4. 0 6.0

20 1.0 4. 0

28 1.0 1.0

Pan-- 1. 0

% of Material

PassingNo. 16 Sieve 2. 0 6.0

*NOTE: The discrepancy between the unaugered 27-14-0 sieve analysis contained inthis table and the unaugered 27-14-0 sieve analysis contained in table 3 isdue to the difference in fertilizer particle sizes from two different manufacturers.


TABLE VI. SIEVE ANALYSIS OF 33.5-0-0 FERTILIZER

Tyler

Canadian Standard

Sieve Series


Unaugered Augered 5 TimesNo

8 11. 0 13. 0

10 32. 0 28. 0

14 51. 0 50. 0

16 4. 0 6. 0

20 1. 0 2. 0

28 0 0

Pan 1. 0 1. 0

% of Material

PassingNo . 1 6 Sieve 2. 0 3. 0

auger before operation can be resumed.

Under normal conditions (augering three to four times) pulverization of the fertilizer is negligible anddoes not affect distribution of thefertilizer from a broadcast spreader.With increased augerings (20 to 60times), however, pulverization became more severe.

REFERENCES

1. Agricultural Materials HandlingManual, Section 2. 3 "Auger andBucket Conveyors" prepared byNational Committee on Agricultural Engineering of National Coordinating Committee on Agricultural Services, Canada Department of Agriculture.

THESE THINGS . . -

continued from page 1

Committee of Agricultural Engineering is an excellent sounding board foraction, and it seems logical that theC.S.A.E. initiate, through this body,ideas that will only bide well for thehealthy condition of Agricultural Engineering in Canada.

It bears repeating that problems ofpollution in air, ground and water aregoing to be amplified in the nearfuture and that efficiency in production will ever be needed on the farmsin this country. These will be handledby individuals and probably handledwell, but it will not be enough to copewith the obvious growth of our nation. Team work is essential and willoccur through either accident or de

2. Guide to Farm Practice in Saskatchewan, 1966, prepared jointlyby representatives of the University of Saskatchewan, Saskatchewan Department of Agricultureand Canada Department of Agriculture.

3. Mickleborough, R. O. "Design andConstruction of a Strain GaugeTorquemeter", Unpublished B.Sc.thesis, University of Saskatchewan,Saskatoon, Saskatchewan, 1962.

4. Reed, W. B. and Wacker, E. "Determination of the DistributionPattern of Dry Fertihzer Applicators", presented at a meeting ofthe A.S.A.E., December, 1968,Paper No. 68-606.

sign. Let us predict it will be by design.

Our Society will grow and witheach new Agricultural Engineer newhopes, new ideas, and new developments will necessarily result. We cannot afford to fail in our dedication toour chosen field when so many aredependent upon so few.

"These things shall be — a loftierrace shall rise."


SOME NEEDS AND . . .

continued from page 2

ern electronic services for information collection, classification, storage,retrieval, and communication towhich facts and technical data lendthemselves admirably. Agriculturalengineers, by virtue of their specialinterests and knowledge, are in anadvantageous position to contributeto such a development.

The research scientist, in turn, relieved of this tedious and endlessactivity and provided more adequately with relevant facts, would bemore likely to exercise his imagination in identifying significant problems within a system and, as a consequence, to generate ideas for theirsolution. The administrator would bemore likely to end up with a teamof 'systems analysts' who are scarce,than of 'programmers' who are plentiful. Conceivably, the trend, whichis not unknown even among agricultural engineers, to become specialists,and thereby run the risk of assignment to irrelevant routine tasks,could be overcome.

The grassland-animal product situation outlined earlier appears to present interesting possibilities for application of the approach suggested.

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power requirements for augering fertilizer and … · power requirements for augering fertilizer...

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