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DEALER

as the cable. The hydrant will be in the middle of the 200 mrun to which one end of the hose will be connected. The otherend of the hose is connected to the machine. The 4 mm drivenozzle is turned to open and the clutch pin is inserted. Whenthe hydrant is opened the machine will move slowly forward.At the end of the 200 m run the machine will automaticallystop moving and should again be set up for the next run.When the machine continues to move in the same directionthe hose can be pulled up to the next hydrant after the waterhas been purged from the hose. One worker will be required tomanually wind the hose onto the hose reel through the rollersas soon as the machine has to be turned around to run in theopposite direction.

Important: Always roll up the hose before transportation.Failure to do so will affect your hose warranty.

Selecting a self propelled irrigatorYou will need to calculate the water requirement (refer to page 2) and to determine the hours and days available for irrigatingthe crop. Remember that 10 m3 spread over 1 ha gives 1mmdepth of water.

GunsBig guns have a reputation for creating large droplets at theend of the stream trajectory and thus soil compaction. Thoseguns that use an impact arm that hits the main stream to turnthe gun have this tendency. While the gun turns the streamsfull length is presented to the atmosphere and break upoccurs. The pause between impacts is when there is littlecontact with the atmosphere and minimal break up occurscreating large droplets which would cause compaction. Someguns use a secondary smaller nozzle to revolve them to avoidthis problem.

Irrigation System EfciencyTests have been carried out by farmers in Zimbabwe in sugar c aneto determine the efciency of the Rainmaker. The 48 x 24mlane spacing system was used and it was found that only 6 % ofthe irrigation water was lost to the atmosphere.

By far the most important inuence on system efciency is thelevel of management decision making. Drip irrigation is saidto be the most efcient water system as losses to atmosphereare negligible but, if too little or too much water is scheduled

the efciency of the whole system may well drop to 20 %.It is of course assumed that the system has been designedcorrectly.

Hose WinderWhere more than one machine is operated it is an option touse a tractor driven hose winder to retrieve the hose and setthe machine up for the next run. Where six or eight machinesare in use and only one worker is available the hose winderwould be recommended.

Droplet Population

When water from a nozzle forms a trajectory it breaks up asit makes contact with air and falls to the ground as thousandsof small droplets. The size of these droplets vary accordingto the size of nozzle and the pressure at the nozzle. Largedroplets are created with big nozzles and low pressure whilesmall droplets are made with high pressure and small nozzles.A rain curtain can be produced with the desired droplet sizeby selecting the correct pressure and nozzle size that will notcompact the soil. Sprinkler type also affects droplet size.

WarrantyRotrix machines are covered by a 1-year factory warranty.

ROTRIXAFRICA INDUSTRIES CC

R A I N M A K E RSELF-PROPELLED IRRIGATION SYSTEMS

Built to irrigate Africamaximising your

farming pro ts

R O T R I XA F R I C A I N D U S T R I E S C C

13 KRONE STREET WORCESTER 685 0 SOUTH AFRICATel: +27 23 3423438 Fax: +27 23 3428469

E-mail: rotrix@intekom.co.za www.rotrixirrigator.co.za

HANDYWORCESTER

E X P

E R

I

E N C E

I N I R RIG AT I O N

S Y S T E

M S

Y EA R S

PERFECT RAIN CURTAIN

MECHANICAL HOSE WINDER

WHEAT

TOBACCO

VEGETABLES

MAIZE

VINEYARDS

SUGAR CANE

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Water RequirementThis is the amount of water measured in mm per monthrequired by a particular crop and will depend on the rainfall,climate and crop factor. It will be necessary to calculate thisamount before selecting the machines most suitable to do thework.

SchedulingThe time available between irrigation cycles will need to bescheduled to provide enough settings for the travelling irrigatorto cover the total area to be irrigated.

CropsOverhead sprinkler irrigation has been used on just aboutevery crop. Travelling irrigators are another form of overheadirrigation. The sprinkler is winched slowly forward at apressure of 3 bar or less and eliminates the use of quickcoupling pipes.

Low PressureMost irrigation systems including drip and microjet irrigationrequire a pressure at the lters of around 3 bar. The operatingpressure of the Rotrix travelling irrigator is also around 3 bar.

Management of the Irrigation SystemAs the machine is very visible it is not difcult to plan itsschedule and to know where it should be irrigating on a certainday.

MaintenanceOwing to the simple construction of the machine it has a lowmaintenance requirement and it is not necessary to use oil orgrease as the large open turbine gearbox is sealed.

Low Tech DesignOver the last 24 years the Rotrix Rainmaker has proved itselfin the agricultural industry as a har d working and trouble freetravelling irrigator. There is very little that can go wrong andparts are available from local agents or ex-factory.

Wind Distortion of the Distribution PatternWind is a negativefactor when usingoverhead sprinklersand the Rainmakeris no exception. Inwindy conditions itis advisable to lowerthe pressure fromsay 3 bar to 2.5bar to increase thedroplet size wherethis is possible. Thelane spacing canbe reduced from36 to 30 m or useshould be made ofthe 48 x 24 m laneskipping system (seewebsite).

PrecipitationMeasured in mm/h is the rate at which water enters the soil.It varies between 6 and 15 mm/h and will depend upon theinltration rate of the soil.

CapacityThe capacity of the machine is the amount of water it canirrigate measured in m3/h and with the Rotrix range ofirrigators varies between 6 and 40 m3/h.

GerminationBy using 9 millimeter nozzlesat 3 bar pressure it is possibleto germinate seed bedswith a Rainmaker irrigator.If a faster travel speed isrequired, and additionalgearbox sprocket is availableto increase the speed between4-5 hours over 200 m. TheNaan 255/37 sprinkers mayalso be adjusted to keep thepath in front dry until groundhas rmed.

Speed RangeThe speed of the Rainmaker can be set to complete a 200m run between 6 and 12 hours. Tests carried out by theDepartment of Water Affairs show that speed variation iswithin 10%.

Open TurbineLow pressure operation is achieved through the use of a peltonwheel type drive. An irrigation system which uses sprinklerswill be able to use the existing pump to run these machines.

Manual OperationThe Rainmaker machine requires the services of twoworkers for 20 min each time the machine is set up for itsnext 200 m long run.

Energy RequirementIs very similar to the energy r equirement for a sprinkler system.That is why it is easy to run these self propelled irrigatorswith existing motors and mainlines. The Rainmaker requiresabout 5 kw at thebeginning of the hose.

Lay-Flat HoseThe Rotrix Rainmakeruses an easily rolledup imported irrigationhose with a 2-year pro-rata warranty.

TransportationIf it is necessary touse the machine fortwo crops say, maizeand tobacco, then themachine is moved from one land to another by loading ontoa pick-up or by towing it behind a tractor. The mass of theRainmaker is 180 kg.

Setting up the machine for a 200 m runThe Rainmaker is brought to the beginning of the lane andthe 200 m cable is drawn off the winch and anchored at theend of the lane. The lay-at irrigation hose is drawn off thehose reel through the rollers for 100 m in the same direction

USEFUL IRRIGATION INFORMATION

I D E A L F O R G E R M I N A T I O N O F S E E D B E D S C O M B I N E D W I T H F A S T E R S P R O C K E T S E T

NozzleSize

PressurekPa

No. ofNozzles

Flowm3 /h

LaneSpacing

Application mm Pressure atHydrant kPa

WettedDia m6 h Run 12 h Run

9mm

300 1 5,3 30m 5 ,74 10 ,6 320 4436m 4,10 8,2

350 1 5,7 30m 5 ,75 11,5 370 4636m 4,80 9,6

300 2 10,6 30m 1 0,6 21 ,2 330 4436m 8,2 16,4

350 2 11,5 30m 11 ,5 23 ,0 380 4636m 9,5 19,0

10mm

300 1 6,6 30m 6,6 13,2 320 4536m 5,5 11,0

350 1 7,1 30m 7,1 14,2 370 4736m 5,9 11,8

300 2 13,2 30m 1 3,2 26,4 330 453 6m 11,0 22,0

350 2 14,2 30m 1 4,2 28,4 380 473 6m 11,8 23,6

11mm

300 1 8,0 30m 8,0 16,0 320 4636m 6,6 13,2

350 1 8,6 30m 8,6 17,2 370 4836m 7,0 14,0

300 2 16 30m 1 6,0 32,0 340 463 6m 1 3,2 26,4

350 2 17,2 30m 16,2 32,4 390 4836m 14,0 28,0

12mm

300 1 10,2 30m 9,3 18,6 320 4736m 7,75 15,5

350 1 11,0 30m 8,2 16,6 370 4936m 6,9 13,8

300 2 20,4 30m 18,6 37,2 350 4736m 15,5 31,0

350 2 22,0 30m 16,6 32,2 400 4936m 13,8 27,6

13mm

300 1 11,3 30m 10,9 21,8 320 4936m 9,0 18,0

350 1 12,1 30m 12,6 25,2 370 5036m 10,5 21,0

300 2 22.5 30 m 21 ,8 4 3,6 360 4936 m 18 ,1 3 6,2

350 2 24.2 30 m 25 ,2 5 0,4 410 5036 m 21 ,3 4 2,6

14mm

300 1 12,7 30 m 12 ,7 2 5,4 330 5036 m 10,6 21 ,2

350 1 14,7 30 m 14,7 29 ,4 380 5136m 12,3 24 ,6

300 2 25..2 30m 25,5 51 ,0 360 5036m 21,3 42 ,6

350 2 27,5 30m 27,5 55 ,0 420 5136m 23,0 46 ,0

S M A L L D R O P L E T P O P U L A T I O N W I T H G O O D R A I N C U R T A I N

NozzleSize

PressurekPa

No. ofNozzles

Flowm3 /h

LaneSpacing

Application mm Pressure atHydrant kPa

WettedDia m6 h Run 12 h Run

15mm

300 1 15,5 30m 1 4,5 29,0 330 513 6m 1 2,0 24,0

350 1 16,7 30m 1 5,6 31,2 380 523 6m 1 3,0 26,0

400 1 18,0 30m 1 6,7 33,4 440 533 6m 1 3,9 27,8

300 2 31,0 30m 2 9,0 58,0 380 513 6m 2 4,1 48,2

350 2 33,5 30m 3 1,2 62,4 440 5236m 26,0 52,0

400 2 36,0 30m 33,4 66,8 550 5336m 27,8 56,6

16mm

300 1 16,5 30m 15,5 31,0 350 5136m 13,0 26,0

350 1 17,7 30m 16,7 33,4 420 5236m 13,9 27,8

400 1 19,4 30m 18,0 36,0 480 5336m 15,0 30,0

300 2 33,0 30m 31,0 61,0 430 5136m 25,8 51,6

350 2 35,0 30m 33,5 67,0 500 5236m 27,9 55,8

400 2 38,8 30m 36,0 72,0 580 5336 m 30 ,0 6 0,0

Rotrix Irrigators are unique irrigation systems with many advantages Capital cost per ha dramatically reduced. The IRRIGATORS can be moved and set-up by two Labour saving system with low running costs. operators Irrigates large areas without supervision. Can be used with existing pump and mainline systems. Water application can be adjusted and well managed. Quickly set-up or moved from one eld to another.

PERFORMANCE CHART FOR ROTRIX IRRIGATORS USING NAAN 255/31 SPRINKLERS AND 200M LONG RUNS

CALCULATIONS TO SELECT THE CORRECT NOZZLES FOR YO UR RAINMAKER1. Q: How many m 3 of water do I need to apply 20mm net to 2 ha? A: 1 mm of water over 1 ha = 10 m 3 therefore 20 x 10 x 2 = 470 m 3

0,85

2. Q: What ow rate do I need in the above case if my irrigation cycle is 3 days and I can pumpwater to the irrigator for 6 hours per day?

A: 470 = 26 m 3/h Select 2 x 14 mm nozzles at 300 kPa and 36 m 6 x 3 lane spacing for Rotrix Rainmaker Irrigator.

3. Q: What is the maximum and the minimum travelling speed of the irrigator? A: A 200 m run can be completed between 6 and 12 hours depending upon drive pressure

settings.

4. Q: How ef cient is my overhead irrigation system? A: More water is lost to sun and wind at low application rates. The application rate should

be equal to the maximum absorbtion rate of a particular soil type for ef ciencies of up to90%. Set pressure at sprinkler correctly to avoid misting which is responsible for mostwater losses. Choose lower pressure.

5. EXAMPLE TO IRRIGATE 10HA APPLYING 35 mm OF WATER Q: I would like to apply 35 mm net to an area of 10 ha per week (7 days)?

A: First determine your lane scheduling , eg. 2 x 11 h runs per day over an area of 200 m x 500 m using a lane spacing of 36 m, will cover 10 ha in 14 runs.

Second calculate the volume required = 35 mm x 10 x 10 = 4118 m 3 0,85 ef ciency Third calculate the fow m 3 /h required = 4118 m

3 = 27 m 3/h 11 h x 2/day x 7 day cycle

From the performance chart select 14 mm nozzles x 2 = 27,5 m 3/h @ 3,5 bar.

Application rate @ 36 m lane spacing per 11 h runs = 46 mm/12 h run x 11 h runs 12 h run for 46 mm = 42 mm per 11 h run over 200 mIf conditions are windy consider selecting the 30 m lane spacing.

I D E A L F O R E S T A B L I S H E D C R O P S

, W H E A T ,

S U G A R C A N E

, B A N A N A S A N D M A I Z E

S U I T A B L E F O R L I G H T W I N D Y C O N D I T I O N S

NozzleSize

PressurekPa

Flowm3 /h

LaneSpacing

Application mm WettedDia m6 h Run 12 h Run

14,5+

8,5

4 00 2 2, 5 42m 1 6,0 32,0 6448m 14,0 28,0

5 00 2 5, 1 42m 17,8 35,6 6848m 15,6 31,2

16+

8,5

4 00 2 5, 7 42m 18,3 34,0 6848m 16,0 30,0

5 00 2 8, 8 42m 24,5 39,0 7448m 21,4 36,0

18+

8,5

4 00 2 9, 0 42m 18,3 36,6 6848m 16,0 32,0

5 00 3 4, 3 42m 24,5 49,0 7848m 21,4 42,8

20+

8,5

4 00 3 6, 2 42m 25,8 51,6 7448m 22,6 45,2

5 00 4 0, 4 42m 28,8 57,6 8048m 25,2 50,4

NAAN 268/31 RAIN GUN

NAAN268/31

HOSEWINDER

2 xNAAN255/31

E x t e n

d s

t o 3 m e

t r e s

f o r

t a l l r o w c r o p s

Wetted diameter 50 metres

TYPICAL METHOD OF OPERATING IRRIGATOR

LANE SPACING OPTIONS NAAN 255 SPRINKLER

CROPS SUITABLE FOR RAINMAKERMaize Wheat Potatoes Soya Beans

Paprica Tobacco Sugar CaneVegetables Onions Pastures

Lucern Vineyards Citrus

MAIN LINE

HOS E

20 0

HYDRANT

18 mHYDRANT

36 m HYDRANT36 m

36 m

3 R D

R U

N 2 N D R

U N 1 S T R U N