The Versatility of the “Atomizador”
In the dense citrus orchards of São Paulo and the mountainous coffee regions of Minas Gerais, pest control requires precision. The tool of choice is the Air-blast Sprayer (Atomizador). However, treating a young coffee bush requires a gentle breeze, while penetrating the thick canopy of a mature orange tree to combat *Greening* (HLB) demands a hurricane-force gale. A single-speed fan cannot do both efficiently.
This is where the 2-Speed Fan Speed Increaser Gearbox (Caixa Multiplicadora de Duas Velocidades) becomes essential. This advanced drivetrain component sits between the tractor PTO and the axial fan. It allows the operator to mechanically shift between a “Low” gear (usually 1:3.5 ratio) for lighter applications and a “High” gear (1:4.5 ratio) for maximum air volume, plus a “Neutral” position for mixing chemicals without air blast.
EVER-POWER's DS-Series (Dual Speed) gearboxes are the gold standard for this application. Engineered with a robust internal shifting collar and an integrated Sprag Overrunning Clutch (Roda Livre), they protect the tractor PTO from the immense inertia of the heavy fan blades during shutdown, ensuring safety and longevity in the demanding Brazilian agribusiness environment.
Technical Specifications: DS-Series (2-Speed Fan Drive)
| Parâmetro | Especificação | Parâmetro | Especificação |
|---|---|---|---|
| Potência de entrada nominal | 40 HP – 90 HP (30-67 kW) | Gear 1 Ratio (Low) | 1:3.5 (Speed Up) |
| Velocidade de entrada | 540 RPM | Gear 2 Ratio (High) | 1:4.5 (Speed Up) |
| Material de construção | Ferro fundido HT250 / Alumínio | Shift Mechanism | Sliding Collar (Dog Clutch) |
| Eixo de entrada | 1-3/8″ Z6 (Through Shaft) | Eixo de saída | Flanged Hub / Tapered |
| Tipo de engrenagem | Helical (Ground Profile) | Material da engrenagem | 20CrMnTiH (endurecido superficialmente) |
| Tipo de rolamento | Bola de alta velocidade / Cônica | Embreagem de roda livre | Internal Sprag (Freewheel) |
| Sistema de Vedação | Viton (FKM) High Temp | Fan Support | Up to 1000mm Diameter |
| Lubrificação | Óleo sintético (ISO VG 150) | Capacidade de óleo | 1.8 Liters – 3.0 Liters |
| Eixo passante | Yes (For Pump Drive) | Pump Drive Speed | 540 RPM (1:1 Ratio) |
| Peso (seco) | 40 kg – 65 kg | Resfriamento | Aero-Fins (Airflow cooled) |
| Pintar | Epóxi resistente a produtos químicos | Garantia | 24 meses |
| Montagem | Comer / Bondioli Standard | Posição neutra | Yes (Fan Disengaged) |
Engineering the “Multi-Speed” Core
1. The Sliding Collar Mechanism
Changing speeds in a fan gearbox is different from a car. We use a robust Dog Clutch Sliding Collar. The gears for Low (1:3.5) and High (1:4.5) are constantly in mesh but spin freely on the shaft. The shift lever moves a splined collar that locks either the Low or High gear to the shaft. This simple, rugged design eliminates synchromesh rings which would fail under the high inertial loads of the fan, ensuring positive engagement every time.
2. The Safety of Neutral
Between the Low and High gears sits the Posição neutra. This is a critical operational feature. It allows the tractor PTO to remain engaged—driving the chemical pump via the through-shaft—while the fan remains stationary. This is essential for tank agitation (mixing) at the depot or when using a hand-gun hose reel for spot spraying, preventing chemical drift and saving fuel.
3. Sprag Clutch Inertia Management
A 900mm aluminum fan spinning at 2,400 RPM acts like a massive flywheel. If the PTO is disengaged suddenly, this stored energy tries to drive the tractor engine. This “Back-Driving” can snap PTO shafts or damage the transmission. EVER-POWER integrates an internal Sprag Overrunning Clutch. This mechanism allows the fan to coast down freely (freewheel) when input power is cut, isolating the harmful inertia from the drivetrain.
4. Dissipação Térmica
Operating at high speeds generates heat. However, the gearbox has a natural advantage: it sits in the eye of the storm. We design the housing with Aletas de resfriamento aerodinâmicas aligned with the intake airflow of the sprayer fan. This forced convection keeps the oil temperature well within the safe range for the synthetic lubricant, even during continuous operation in Brazil’s 40°C summers.
Comparative Analysis: 2-Speed vs. Single Speed vs. Hydraulic
| Recurso | 2-Speed Gearbox (DS Series) | Single Speed Box | Hydraulic Fan Drive |
|---|---|---|---|
| Versatility | High (3 Modes: Lo/Hi/Neu) | Low (One air volume) | Very High (Infinite) |
| Eficiência | Alto (96% Mecânico) | High (97%) | Low (70% – Heat loss) |
| Custo | Médio | Baixo | Muito alto |
| Segurança | High (Integrated Clutch) | Medium (Often external) | High (Relief valve) |
| Manutenção | Troca de óleo | Troca de óleo | Complex (Filters/Hoses) |
*Analysis based on citrus farm data in Araraquara, SP.
Aplicação localizada: Agronegócio brasileiro
Cítricos (São Paulo)
The “Citrus Belt” requires machines that can switch between spraying young saplings (Low Gear) to save fuel and chemical, and blasting mature trees with dense canopies (High Gear) to control the Psyllid vector of Greening. Our DS-Series provides the High-Ratio (1:4.5) needed to spin 900mm fans at 2,400 RPM for maximum penetration.
Coffee (Sul de Minas)
Coffee sprayers are often smaller and tractor power is limited on steep slopes. The Marcha reduzida (1:3,5) option allows farmers to operate effective spraying using smaller tractors (50-65 HP), maintaining good coverage without stalling the engine on uphill climbs.
📒 Field Engineer’s Log: The “Crunching” Shift
“September 2025, Bebedouro, SP. A fleet manager reported broken shift forks in their new sprayers. The operators were complaining about grinding noises.”
“We discovered the operators were trying to shift gears while the fan was still spinning down (freewheeling). Although the tractor PTO was off, the fan momentum kept the internal gears moving. Shifting a dog clutch while moving causes grinding.
Solution: We couldn’t change operator behavior easily, so we upgraded the Shift Collar Material to a higher-hardness nitrided steel and added a ‘Positive Detent’ mechanism that requires a deliberate pause in Neutral. We also added a warning decal: ‘WAIT FOR FAN STOP’. The failures ceased, and the gearboxes have run flawlessly for two seasons.”
Perguntas frequentes (OEM/B2B)
1. Can I shift gears while the PTO is running?
Absolutely NOT. This is a non-synchronized crashbox. You must disengage the tractor PTO and wait for the fan to come to a complete stop before moving the lever. Attempting to shift while rotating will destroy the dog clutch teeth.
2. Does the through-shaft stop in Neutral?
No. The through-shaft (driving the chemical pump) is directly connected to the input shaft. It rotates whenever the tractor PTO is turning, regardless of the gear lever position (Low, Neutral, or High). This ensures pump agitation is always available.
3. Are parts compatible with Comer or Bondioli?
Our DS-Series is designed as a direct replacement for many industry-standard European gearboxes (Comet, Bondioli & Pavesi). The mounting bolt pattern and output hub dimensions are identical for easy retrofitting on existing sprayer chassis.
4. What oil should be used?
Due to the high operating speeds (up to 2,500 RPM output), we strictly recommend Synthetic Gear Oil (ISO VG 150 or 75W-90). Mineral oils may foam or break down under the high shear and heat of a speed increaser.
Complete Your Sprayer Drivetrain
Embreagens centrífugas
Optional output hub that provides a “Soft Start” for the fan.
Adaptadores de bomba
Flanges to mount Jacto/Comet pumps to the rear through-shaft.
Control the Wind, Protect the Crop
Upgrade your sprayers with EVER-POWER 2-Speed Gearboxes for ultimate flexibility and safety.
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