Combating Pests with Velocity
Brazil holds the title of the world’s largest orange producer and coffee exporter. These high-value crops face constant threats from pests and diseases like Greening (Huanglongbing) in citrus and Hemileia vastatrix (Rust) in coffee. The primary weapon against these threats is the Air Blast Sprayer (Atomizador). This machine relies on a powerful fan to generate a high-velocity air curtain that carries micronized chemical droplets deep into the dense canopy of trees.
The heart of the atomizer is the Fan Drive Gearbox (Caixa Multiplicadora de Velocidade). Unlike most agricultural gearboxes that reduce speed to increase torque, this unit acts as a Speed Increaser. It takes the standard tractor PTO input of 540 RPM and amplifies it to 1,800 or 2,200 RPM to drive the large axial fan.
EVER-POWER’s FD-Series (Fan Drive) gearboxes are engineered specifically for the thermal and inertial challenges of this application. They feature a built-in Overrunning Clutch (Roda Livre) to handle the massive flywheel effect of the fan during shutdown, and a 2-speed shift mechanism (plus Neutral) to allow farmers to adjust air volume based on tree maturity and foliage density.
Technical Specifications: FD-Series (Sprayer Multiplier)
| Parameter | Specification | Parameter | Specification |
|---|---|---|---|
| Rated Input Power | 40 HP – 110 HP (30-82 kW) | Ratios (2-Speed) | 1:3.5 / 1:4.5 (Step-up) |
| Input Speed | 540 RPM | Fan Speed (Output) | 1890 / 2430 RPM |
| Housing Material | Cast Iron HT250 / Aluminum | Max Output Torque | 600 Nm (High Speed) |
| Input Shaft | 1-3/8″ Z6 (DIN 9611) | Output Shaft | Flange / Taper / Cylindrical |
| Gear Type | High-Speed Helical / Bevel | Gear Material | 20CrMnTiH (Grinding Class 5) |
| Bearing Type | High-Speed Ball / Tapered | Shifting | Manual Lever (Low-Neutral-High) |
| Overrunning Clutch | Integrated Internal Sprag | Cooling | Airflow Design |
| Lubrication | Synthetic Oil (ISO VG 150) | Oil Capacity | 1.2 Liters – 2.5 Liters |
| Through Shaft | Yes (For Chemical Pump) | Through Shaft Type | 1-3/8″ Z6 (540 RPM) |
| Weight (Dry) | 25 kg – 55 kg | Fan Diameter Support | 600mm – 1000mm |
| Paint | Heat Resistant Epoxy | Warranty | 24 Months |
| Mounting Pattern | Comer / Bondioli Standard | Thermal Limit | 120°C (Requires Airflow) |
Engineering the “Speed Increaser”
1. The Inertia Problem (Free Wheel)
An 800mm fan spinning at 2,000 RPM has immense kinetic energy. If the tractor operator disengages the PTO suddenly, the fan wants to keep spinning, but the tractor engine stops. Without protection, this inertia would destroy the gearbox teeth or twist the PTO shaft. EVER-POWER integrates a heavy-duty Overrunning Clutch (Roda Livre) inside the gearbox. This allows the fan to coast down safely for minutes after power is cut, protecting the drivetrain.
2. Thermal Management at High RPM
Speed increasers generate more heat than reducers due to fluid friction at high agitation speeds. However, the fan gearbox has a unique advantage: it sits directly in the airflow path. Our housing is designed with Aerodynamic Cooling Fins that harness the 100 km/h wind generated by the sprayer fan to actively cool the oil sump, keeping temperatures stable even in the 40°C heat of Ribeirão Preto.
3. The “Neutral” Importance
Sprayer operators need to mix chemicals in the tank without running the fan (to avoid blowing expensive chemicals away). Our FD-Series features a Three-Position Lever (High Speed – Neutral – Low Speed). The neutral position disconnects the fan while keeping the through-shaft spinning, allowing the rear-mounted diaphragm pump to continue agitating the tank mixture.
4. Through-Shaft Configuration
A sprayer needs to drive two things: the Fan (Air) and the Pump (Liquid). Our gearboxes feature a Through-Shaft (Eixo Passante). The PTO power enters the front, drives the step-up gears for the fan, and passes straight through the back at 1:1 speed (540 RPM) to drive the high-pressure ceramic plunger pump or diaphragm pump mounted at the rear of the machine.
Comparative Analysis: Gearbox vs. Belt Drive
| Feature | Gearbox Drive (FD Series) | Belt & Pulley Drive |
|---|---|---|
| Efficiency | High (97% – No Slip) | Medium (Slippage common) |
| Maintenance | Low (Oil Change) | High (Belt Tension/Replace) |
| Compactness | Very Compact | Bulky (Requires Guards) |
| Speed Change | Instant Lever Shift | Swap Pulleys (Slow) |
| Cost | Higher Initial | Lower Initial |
*Data derived from performance tests in Araraquara citrus groves.
Localized Application: Brazil Agri-Business
Citrus (São Paulo)
Citrus trees are dense and tall. Penetrating the canopy to kill psyllids (Greening vector) requires maximum air velocity. Farmers use the High Gear (1:4.5) to spin the fan at 2,200 RPM, creating a storm that flips leaves and coats the undersides. Our gearboxes are built to run at this red-line speed all day.
Coffee (Minas Gerais)
Coffee bushes are more delicate. Blasting them with too much air knocks off berries or flowers. Farmers shift to Low Gear (1:3.5) for a gentler breeze that carries the fungicide for Rust control without mechanical damage to the crop.
📒 Field Engineer’s Log: The “Exploding” Fan
“October 2025, Franca, SP. A coffee grower called us. His sprayer gearbox had seized, and the inertia snapped the PTO shaft. We investigated.”
“The internal overrunning clutch (sprag) had rusted solid. The farmer had been washing the machine with a high-pressure jet, forcing water through the breather. When he disengaged the PTO at 2000 RPM, the locked clutch forced the tractor engine to stop the fan instantly. Something had to break.
Solution: We replaced the unit with our Sealed Sprag Design and installed a ‘Labryinth Cap’ breather that blocks direct water jets. We also advised the farmer to check the clutch freewheeling action by hand before every season.”
Frequently Asked Questions (OEM/B2B)
1. Can I use this gearbox for a tower sprayer?
Yes. The FD-Series output shaft is typically a flange designed to bolt onto the fan hub. It supports both standard axial fans and “Tower” (Torre) deflectors used in dense orchards, provided the fan assembly is balanced (G6.3 grade).
2. What happens if I shift gears while running?
Never do this. The gearbox uses a sliding collar mechanism (dog clutch). Shifting under load or rotation will grind the gears and can shear the shift forks. Always stop the PTO and let the fan stop completely before changing speed.
3. Do you supply the propeller hub?
We offer output shafts with standard metric flanges or cylindrical keys. We can also supply a specialized Centrifugal Clutch Hub as an add-on, which provides a soft start for the fan, reducing wear on the gearbox gears.
4. Is synthetic oil required?
Yes. Due to the high RPM (2,200+) and speed-increasing nature (which generates heat), we strongly recommend Synthetic ISO VG 150 or 220. Mineral oils oxidize too quickly at these temperatures, leading to sludge buildup.
Complete Your Spraying System
Velocity Meets Reliability
Equip your atomizers with EVER-POWER Fan Drives for consistent air blast performance.
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Major Markets: Brazil, Italy, Spain, South Africa, USA.
