Big sprayers keep growing

FARGO, N.D. — In the high-stakes contest to have the biggest self-propelled high clearance sprayer, Hardi’s Rubicon 9000 with a 2,200 gallon tank and 160-foot front mount aluminum boom is the new leader.

In keeping with the latest sprayer technology, Rubicon booms are mounted out front of the cab and all liquids are carried in the middle of the 15-foot wheelbase so weight distribution remains 49 percent front and 51 percent rear whether tanks are empty or full.

Everything about the Rubicon 9000 is super-sized, including ground clearance. A six-foot farmer can walk under the chassis and not worry that his cap will catch the lowest point under the machine, thanks to the 72-inch ground clearance. Power comes from a 380 horsepower Cummins 8.9 litre QSL 9 engine. Four-wheel drive comes from a hydrostatic transmission. Four-wheel steering gives the operator better control and reduces ridging in the headlands. The rinse tank holds 165 gallons. The fuel tank holds 265.

Needless to say, Hardi also super-sized Rubicon’s performance. Sprayer performance depends on three factors: ground speed, liquid capacity and boom width. A transit speed of 35 m.p.h. means less time moving from field to field. Spray speed of 20 m.p.h. with the 160-foot aluminum boom means the machine can put down 13 gallons per acre and squeeze out 185 acres per tank fill. At high-end rates, it can put down 26 gallons per acre and spray 92 acres per tank fill.

In field demonstrations, a Rubicon with a 150-foot boom at 20 m.p.h. covered 309 acres per hour. That pencils out to 2,781 acres in a normal work day, according to Hardi’s Ben Kinzenbaw, who was at the Big Iron Farm Show held in Fargo on Sept. 10-12.

“I know some guys will go faster than 20 (mph), but we think you can cover a lot of ground in a day keeping it at the recommended 20,” says Kinzenbaw.

“However, we have done field trials at 30 m.p.h. with the boom set at 20 inches. We did turns in the headlands at 20 m.p.h. without having the boom touch the ground.”

According to Hardi, spring tension holds the centre frame in the middle while hydraulic dampers absorb energy from the boom movement. A hydraulic actuator exerts the correct amount of pressure to change the resistance. Two nitrogen accumulator plunge cylinders on the para-lift provide the boom with vertical shock absorption and height control. The result is a boom that remains stable under extreme conditions. Boom height ranges from 20 inches to nine feet.

The aluminum booms are from Pommier and are available on the Rubicon in a bi-fold 120-foot, 150-foot and 160-foot widths. Pommier says their wings are half the weight of equivalent width steel wings. The auto-height control system uses five ultrasonic sensors, which can take readings from either the soil or the crop. They are designed to maintain accurate boom height at speeds up to 22 mph.

“There’s another reason we say you’ll still get good boom control at that speed. Our engineers put a lot of work into the air bag suspension. Each wheel is sprung independent of the others. The low-pressure air springs give the machine a softer ride so the boom has a more stable ride, and they (air bags) keep the tires in contact with any surface you might be spraying on.”

With 72 inches ground clearance and a very clean smooth underbody, operators can work in tall crops during late season applications. Track width is adjustable on-the-go from 118 inches out to 157 inches. In transit, everything folds up to 12 feet wide.

The transmission uses the Danfoss 250 cubic centimetre, variable displacement axial piston pump driving variable displacement Danfoss H1 bent-axis axial piston wheel motors.

These Danfoss systems are integrated with the Cummins CAN platform. The micro-controller measures the speed at each wheel 86 times per revolution to minimize slippage and maximize torque. Each wheel is managed individually according to gradient, soil, load and other factors. An advanced engine cooling system allows the sprayer to run with only 53 gallons of hydraulic oil.

On the spraying side, product is delivered by a 180 gallons per minute ACE centrifugal wet seal run dry pump, which is managed by a hydraulic pulse width modulation valve.

Suction from the main tank, rinse tank or external supply is through a three-inch hydraulically operated rotary valve. A similar two-inch hydraulically operated rotary valve controls the supply to the boom recirculation system nozzles, the chemical filler or for pressure empty. A dedicated hydraulically driven 18 gallons per minute diaphragm pump with electric rotary control valve is for clean water to the main tank, rinse nozzles, priming the ACE pump or for the hand gun.

The fluid system automatically switches to recirculation as soon as the tank is recharged, allowing the operator to get to work as soon as the boom is unfolded. The system also lets the operator run clean water through the boom and back to the main tank instead of spraying it on the ground.

The ActivAir rapid on/off nozzle control taps into the Rubicon’s on-board air system to instantly open and close the non-drip nozzles. Air pressure is distributed along the boom through eight-millimetre tubes to electrically actuated solenoids, then through four-mm tubes to each non-drip valve. The system is divided into 14 sections for minimal overspray when AutoSection is used.

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