9 August 2002

Self-levelling range more evolution than revolution

Sands Agricultural Machinery

recently introduced its new

generation of SL sprayers

with improved comfort, self-

levelling suspension and an

intelligent hydrostatic

transmission. Geoff Ashcroft

got behind the wheel of an

SL3000 to check it out

SANDS Agricultural Machinery (SAM) believes its new self-levelling sprayer range is more evolutionary than revolutionary.

"SL replaces our traditional M class sprayer and its development is the result of feedback from operators who initially wanted much more comfort from their machines," says SAMs managing director, Neal Sands.

Key developments include an upgrade to the operators cab, the introduction of hydro-pneumatic self-levelling suspension on both axles and the firms optional Smart Drive system – the latter is a hydrostatic transmission which comes with traction control.

With the standard hydrostatic transmission, operators can choose from four transmission modes via a rotary control switch. It allows the selection of road, max traction, uphill/level spraying and steep downhill modes.

"It is a variable torque displacement system that provides different performance characteristics to suit field and road use," says Mr Sands. "As machine weight shifts from front to rear and vice-versa, the amount of torque available to each wheel motor needs to be varied to maintain an accurate forward speed."

The optional Smart Drive system takes hydrostatic transmission technology a step further. The Poclain-developed system uses sensors on each wheel to monitor the average wheel speed across all four wheels, determining how much speed difference is acceptable between all four wheels.

Should one or more wheels start to turn outside these parameters, Smart Drive momentarily stops the over-speeding wheel then modulates its speed to bring it in line with the other wheels – the result, says SAM is an effective form of traction control with a hydrostatic transmission.

"Its intervention is undetectable from the cab," he says. "It means you keep moving in conditions that would usually require assistance from extra farm vehicles with tow chains."

Three models make up the SAM SL range: SL2500, SL3000 and SL4000, with model designations that reflect the capacity of their spray tanks, in litres. Standard boom width on all three is a 12/24m Gullwing folding boom, though wider versions are available.

So what is the SL like to drive? farmers weekly travelled to Sands Brunstead, Norfolk, premises to try out the firms SL3000 – a 3000-litre demonstrator equipped with Smart Drive and a 24m Gullwing boom.

Climbing into the forward control cab, it is easy to appreciate the generous door opening and masses of space inside the cab. Its presence is almost Tardis-like with no shortage of legroom, headroom and all-round visibility.

Air suspension

Once comfortable on the air-suspension seat, the first point to note is the overall simplicity of the cabs layout – the roof panel carries the heating, air conditioning and ventilation controls, while the right-hand armrest and console carry all sprayer functions.

SAM says it has done much to simplify sprayer operation. The armrest-mounted joystick carries the most frequently used, essential sprayer controls – which, on the 24m boom, is all seven boom section controls and the forward/reverse function for the hydrostatic transmission, activated by pushing the lever forward and backwards.

Other machine functions, including the hand throttle, boom folding, steering mode selection and a series of LEDs to show which sections of boom are switched on, reside on the right-hand console.

On the cab floor, almost at the foot of the windscreen, are two pedals. The left pedal is used to activate four-wheel steering for headland turns, while the right foot pedal is the main spray on/off function.

Turning the key brings the 133hp Deutz six-cylinder turbocharged engine to life. After a few seconds, the hydro-pneumatic suspension senses the load on each axle and levels the sprayer to an even pitch.

Then with the handbrake released, a push of the joystick brings movement. No surprises yet, but switching on the four-wheel steering throws up the first clever function. Only the front axle is steered until the operator decides to implement tighter turning circles.

This is achieved by pressing the left-foot pedal to indicate that four-wheel steering is required and when the system detects that both axles are facing straight ahead, it automatically steers both axles to achieve a turning circle of just 6m.

Once activated, four-wheel steering stays in operation until the operator releases the foot pedal and two-wheel steering is resumed when the rear axle reaches the straight-ahead position and locks into place.

It is surprisingly simple to operate with machine controls being both precise and easy to use. The conclusion is that, despite topping £60,000, SAM will continue to hold a big share of the self-propelled sprayer market. &#42