Overview
The Irrimec OPTI RAIN ST4 is a water-powered turbine drive hard hose irrigator designed and manufactured in Italy by Irrimec, a leading European irrigation equipment specialist. This hose reel irrigator utilises the pressure of the irrigation water itself to power its rewinding mechanism, eliminating the need for external fuel or electricity sources. Available in hose diameters ranging from 75 mm to 110 mm and lengths from 200 m to 430 m, the ST4 delivers reliable coverage across medium to large irrigation areas, making it an economical choice for farms and operations seeking consistent performance with minimal running costs.
What distinguishes the OPTI RAIN ST4 within the turbine drive hard hose irrigator category is its robust turbine-to-gearbox integration, precision chain drive transmission, and engineered hose guide system that ensures uniform winding under variable field conditions. The galvanised chassis treatment provides exceptional corrosion resistance for long service life, while the cart platform design offers stability during transport and operation across diverse terrain. With fourteen available hose configurations spanning four diameter classes, the ST4 provides operational flexibility to match specific flow rates, pressures, and field dimensions without the complexity or maintenance demands of engine-driven reels.
Key Features & Benefits
- Water-Powered Turbine Drive: Eliminates all fuel and electricity costs by harnessing the energy of the irrigation water supply itself — ideal for remote paddocks, leased land, and operations seeking to reduce carbon footprint and operating expenses.
- Integrated Gearbox and Chain Transmission: Delivers precise, controlled hose rewinding speed proportional to water flow, ensuring uniform retrieval without jerking or uneven winding that can damage hose or raingun.
- Built-In Speed Control Valve: Allows fine-tuning of rewinding speed by adjusting turbine by-pass flow, giving operators full control over irrigation travel rate to match soil infiltration and crop water requirements.
- Low Maintenance Operation: With no engine, fuel system, spark plugs, or oil changes required, the ST4 reduces scheduled maintenance to periodic lubrication and inspection — maximising uptime and lowering total cost of ownership.
- Engineered Hose Guide System: Ensures consistent, uniform winding across the full hose length, preventing overlap or gaps that lead to premature hose wear and extending service life.
- Galvanised Chassis Construction: Provides superior corrosion resistance against water, fertiliser, and environmental exposure, ensuring structural integrity and longevity in demanding agricultural conditions.
- Four Hose Diameter Options: Accommodates flow rates from moderate to high capacity, allowing operators to select the optimal diameter-length combination for specific field dimensions, pressure availability, and raingun specifications.
- Silent and Reliable Operation: The water-driven turbine operates quietly without engine noise, vibration, or exhaust emissions, making it suitable for sensitive environments and residential-adjacent properties.
Technical Specifications
| Specification |
Details |
| Manufacturer |
Irrimec |
| Model |
OPTI RAIN ST4 |
| Product Type |
Turbine Drive Hard Hose Irrigator |
| Drive System |
Water-Powered Turbine |
| Transmission |
Chain Drive with Gearbox |
| Hose Diameter Range |
75-110 mm (2.95-4.33 in) |
| Hose Length Range |
200-430 m (656-1,411 ft) |
| Speed Control |
Adjustable By-Pass Valve |
| Chassis Treatment |
Galvanised Steel |
| Cart Configuration |
Four-Wheel Stable Platform |
| Country of Manufacture |
Italy |
Available Hose Configurations
| Hose Diameter |
Hose Length |
Configuration Code |
| 75 mm (2.95 in) |
350 m (1,148 ft) |
75 TG |
| 75 mm (2.95 in) |
400 m (1,312 ft) |
75 TG |
| 75 mm (2.95 in) |
430 m (1,411 ft) |
75 TG |
| 82 mm (3.23 in) |
350 m (1,148 ft) |
82 TG |
| 82 mm (3.23 in) |
380 m (1,247 ft) |
82 TG |
| 82 mm (3.23 in) |
400 m (1,312 ft) |
82 TG |
| 90 mm (3.54 in) |
300 m (984 ft) |
90 TG |
| 90 mm (3.54 in) |
320 m (1,050 ft) |
90 TG |
| 90 mm (3.54 in) |
340 m (1,115 ft) |
90 TG |
| 100 mm (3.94 in) |
240 m (787 ft) |
100 TG |
| 100 mm (3.94 in) |
270 m (886 ft) |
100 TG |
| 100 mm (3.94 in) |
300 m (984 ft) |
100 TG |
| 110 mm (4.33 in) |
200 m (656 ft) |
110 TG |
| 110 mm (4.33 in) |
230 m (755 ft) |
110 TG |
Turbine Drive System & Operation
The OPTI RAIN ST4 employs a direct-flanged water turbine mounted to a sealed gearbox that converts irrigation water flow into controlled rotational energy for hose rewinding. As pressurised water passes through the turbine chamber, it spins the turbine blades, which drive the chain transmission system connected to the reel drum. Rewinding speed is directly proportional to water flow rate, providing inherent synchronisation between irrigation application and travel speed. The integrated by-pass valve allows operators to divert a portion of the turbine flow, enabling fine adjustment of rewinding speed to match specific soil types, slopes, and desired application depths without altering mainline pressure or raingun performance.
This water-powered approach delivers significant operational advantages over engine-driven alternatives. With zero fuel consumption, operators eliminate ongoing diesel or petrol costs, refuelling logistics, and exhaust emissions. The turbine system operates silently and requires no electrical connection, making it ideal for remote fields, leased land where infrastructure is limited, and environmentally sensitive areas. Maintenance is minimal — periodic chain lubrication and gearbox inspection replace the complex servicing schedules of combustion engines. Performance remains consistent and predictable, tied directly to water pressure rather than engine tuning, ambient temperature, or mechanical wear. The result is a highly reliable, cost-effective irrigation solution that delivers season after season with minimal intervention.
Ideal Applications
- Remote Pasture and Forage Fields: Perfect for irrigating distant paddocks without access to electricity or where fuel transport is impractical — the water supply itself provides all operating power.
- Large-Scale Row Crop Production: Delivers uniform water application across extended field lengths with consistent travel speed, ensuring even crop establishment and yield optimisation in maize, soybean, cotton, and vegetable production.
- Dairy and Livestock Grazing Systems: Provides reliable, low-noise irrigation for pasture rotation systems where fuel storage presents safety concerns and where operational simplicity reduces labour demands.
- Organic and Sustainable Farming Operations: Aligns with environmental stewardship goals by eliminating fossil fuel consumption, reducing carbon footprint, and operating without engine emissions or lubricant leakage risks.
- Sports Turf and Amenity Landscapes: Offers quiet, consistent operation suitable for parks, golf courses, and athletic fields where noise restrictions apply and where aesthetic considerations favour clean, fume-free equipment.
- Horticulture and Specialty Crops: Enables precise irrigation control for high-value crops requiring specific water application rates, with easy speed adjustment via the by-pass valve to accommodate varying soil conditions and growth stages.
- Leased and Contracted Farmland: Ideal for operations irrigating rental properties where installing permanent electrical infrastructure is not feasible or economically justified, providing full irrigation capability with only a water connection.
