Fixed center pivot system
One end of the machine is fixed and other spans move clock wise by motor drive tires, which is called fixed center pivot system.
River and bore well can be the water resource of the fixed point, the water transports through main pipes and sprinklers, finally applied to the field. The advantage of this system is to use less labor and water to irrigate 13-130ha from one water feeding point. Steel structure of special design can satisfy different lengths of the machine. One span with one overhang (80m) is the simplest machine you can choose for small land. The heavy duty design can be extend to more than 11 spans (650m) with the angles and bolt pivot anchors strong enough to fight windstorm.
| The specification of the Rainfine Center Pivot | |||
| Items | Specification | Items | Specification |
| Pivot length | 41.1-791.2m | Land covered | 0.53-196.7ha |
| Qty.of spans | 1-16 | Span length choice | 41.1/47.8/54.4/61.3m |
| Overhang length | 6.7/13.4/20.1/26.8m | Pivot clearance | 2.91-3.75m |
| Span dia. | 141/168/203mm | Pivot height | 4.62-5.46m |
| Span thickness | 3mm | Surface | Hot dip galvanization |
| Flow rate | 15-1080m3/hr | Water pressure at pivot base | 1-7.5Bar |
| Friction Loss | 0-2.5bar | Tire | 14.9×24 tubeless tire with hot dip galvanized 8×24 rim irrigation special |
| Max speed | 142m/hr | Sprinkler | Nelson/Senninger |
| Regulator | 10/15psi | Type of drops | Flex 5.5-ft drops |
| Gear box | 50:1 heavy duty | Gear motor | 33rpm(full loaded) at 380V.3/4HP 40:1 Ratio. Over-heating protection |
| Control panel | Standard | Required run power | 0.7-11.5kw |
| Power supply | 415V 50HZ | Irrigation Hours/Day | 0-24hr/day |
| Daily applicationrate | 0-50mm/day | Pressure gage | 0-60psi |
Fixed metallic zinc-coated central tower with Maine Panel with Auto, Shutdown & Auto reverse system, main hard on vertical pipe of the water feeding and Press Gauge, Pivot point light, thumbing electrical collector and irrigation end gun managerial system. Feeding by water from pipe line. The central tower fixed, is assembled on concrete foundation.
Metallic zinc-coated Spans rubber-band united between itself, mounted on support of intermediate towers-each with two wheels,<V>-type, axles drive unit from electric geared motor to Wheels gearboxes; the electronic block of the system of the equalization and checking.
Then center pivot can work automatically with the help of control panel. Below are the functions about it: Main breaker and contactor / Control transformer / Start stop switch / Monitoring indicators
Fused disconnect in panel rated 600v at 30 amps / Forward / reverse contactors rated 600v at 30 amps / Fuses - 30 amps / Lightning arrestor / System monitors : control power, pressure, last tower movement, control circuit power, safety circuit status, reverse control circuit, forward control circuit, pump control circuit, Monitors incoming 380V power
Our main control also supports:
No water start stop / Auto reverse/stop / Speed adjusting / Under voltage relay / Over current relay
/ Emergency stop / Low water pressure shut off
Rotational Sprinklers Nelson and Senninger with continuous circular action D12m for careful near-land type irrigation are optimum for all crops type and greatly approximate in drips sizes as natural rain. Fixed on the top part of pipes are the “Gooseneck” and flexible hose by clamp. The sprinklers have an individual pressure-regulator on 1.5 bars, position stabilizer, jet nozzle and revolving from flow of water sprinkling “plate”.
Motion of Rainfine Pivot derives from electric gear-motor to wheels gearboxes with the help of axles, located on each intermediate towers.
The technical data of the gear motor:
Motor | rpm (480v 60hz) | rpm(380v 50hz) | amp | hp | Ratio |
A | 43 | 33 | 1.43 | 0.75 | 40:1 |
B | 30 | 25 | 2.2 | 1.0 | 40:1 |
C | 59 | 49 | 3.0 | 1.0 | 29:1 |
D | 86 | 66 | 1.43 | 1.5 | 20:01 |
Center drive Type (60hz 480v) | Ratio | Drive Speed (RPM)(50hz) | Wheel Speed (RPM) | Tire Size | Distance Per Wheel Rev. | Last Tower Speed@100%(m/hr) |
30 RPM | 40:1 | 25 | 0.5 | 11.2*24 | 3.23 | 97 |
11.2*38 | 4.42 | 133 | ||||
14.9*24 | 3.60 | 108 | ||||
16.9*24 | 3.81 | 114 | ||||
43 RPM | 40:1 | 33 | 0.66 | 11.2*24 | 3.23 | 128 |
11.2*38 | 4.42 | 175 | ||||
14.9*24 | 3.60 | 142 | ||||
16.9*24 | 3.81 | 150 | ||||
59 RPM | 29:1 | 49 | 0.98 | 11.2*24 | 3.23 | 190 |
14.9*24 | 3.60 | 212 | ||||
16.9*24 | 3.81 | 224 |
The gearbox we use:
a The worm consists of high strength forged steel with a Brinell hardness of 210 while the wrong gear is manufactured from ductile cast iron with a relatively wide variation of hardness. This is totally different from those made by grey pig iron.
b The worm and gear pressure angle are designed at 14-1/2 degrees. This angle was selected based on reviewing of extensive engineering information and has supported by extensive testing. It exceeds the necessary strength requirement which makes it in greater efficiency with large angle.
c The output shaft is in full 2-1/4” diameter. Although large shafts can be used, the actual strength is determined by the load applied and physical properties of the material, while our shaft material is high-strength, forged steel. The gearbox overhung load point is relative small at 1-1/2” from the bearing to the wheel mounting flange.
d The worm end caps made of cast iron are held by 4 bolts to reduce the possibility of working loose in the field – unlike some system just with a threaded nut.