Farmers Guardian: Focus on high capacity and high output

WHEN it comes to self-propelled sprayers, there is big and bigger. Then we come to the Lite Trac. We look at how a Cambridgeshire-based contractor is getting on with such a machine.

Source: Farmers Guardian (please click here to see the original article with images)

With a contract to apply Omex liquid suspension fertiliser to over 9,000 hectares (22,000 acres) each year, Richard Redhead considered he could do with a sprayer that would not be too long getting over some large areas.

What he needed, he reasoned, was a high capacity – high output sprayer, which could cope specifically with the high application rates normally required by liquid fertiliser.

After much deliberation, Mr Redhead delivery of a Lite Trac SS240 self-propelled sprayer at the beginning of March – a brute of a machine having an all-up weight of over 20 tonnes.

“For as long as I can remember I’ve been running forward control Unimogs equipped with 24m booms,” he explains. “I always thought they were pretty good but this machine is in another league.”

Visually, the SS240 looks to have the right proportions – cab, tank, boom, wheels – but then so does the Queen Mary until you get close up and realise just how big things are.

Weight distribution

Shod on 800/70 R 38 tyres, its upper deck is dominated by a 5,500 litre stainless steel tank, located centrally to ensure weight distribution is shared equally between the front and rear axles. This is further enhanced by having the engine – a turbocharged and intercooled 260hp Cummins – placed directly beneath the tank.

Before the words ‘service’ and ‘access’ leap to mind, let it be known the whole sprayer deck – tank, pump and booms – can be raised hydraulically to provide unlimited access to the engine.

Transmission is a six-speed Spicer box complete with torque converter and means all changes are clutch-less and made with a small toggle switch. Set in constant four-wheel drive, steering modes can be front only, opposite and most entertainingly, crab.

“It’s quite noticeable how the weight distribution remains constant,” says Mr Redhead. “I have to say, despite the 20 tonne loaded weight, the large diameter, wide tyres help prevent any severe compaction.”

Use of air bag suspension which is able to compensate for weight changes, helps create a soft ride, both for the operator and, more importantly, the booms.

This machine is fitted with 36m aluminium booms built in France by Pommiere – a company that specialises in the production of such equipment. Mounted on a parallel linkage, the support/height rams have gas accumulators to provide suspension.

“With no tramlines to follow, a good, reliable guidance system is essential when operating this sprayer”
Richard Redhead

Opening the boom is achieved hydraulically and follows a sequence which contains the boom within a set distance of the machine to minimise accidental contact with power lines, people or pillars.

For liquid fertiliser application the boom is fitted with 12 flood jets spaced at 3m intervals. Each has its own shut off valve that is activated automatically when that section of the boom is travelling over land already sprayed.

A nice touch is a deflector plate fitted to each of the boom end nozzles, which can be moved into place when spraying headlands and prevent fertiliser from being deposited in the hedgerows.

There are also boom height sensors but these have yet to be used – the system still needs some modifications to the lift rams to allow them to be operated.

A New Holland forage harvester cab with all round glass, air conditioning and weight sensitive pneumatic seat suspension, provides generous levels of operator comfort, while a very cosy looking work station carries banks of switches, touch sensitive screens and the all important gear toggle switch.

One bank of switches is for boom positioning, master spray and manual control of sections while another has light switches and other machine controls.

Satellite guidance

Key to this fertiliser operation though, which is normally applied when the ground is still to be planted and there are no tramlines in place, is a satellite guidance system.

“It’s essential to have automated steering and with it, a system which can record the areas that have been sprayed so there is only minimal overlapping,” he says.

“The SS240 has the Topcon X20 system on board which means, when it is set up, I can just let go of the steering wheel and leave the sprayer to it.”

Application rate can be set and automatically maintained irrespective of forward speed with Mr Redhead normally travelling at about 15kph.

The display also keeps him informed of details such as tank levels, hectares sprayed and field sizes, for example.

“In terms of output, I consider 100 hectares a day to be near the mark,” he says. “Depending on application rate, a full tank does about seven hectares which doesn’t take very long to apply.”

So what’s the verdict after just a few weeks’ operation?

“Overall, it’s a first class sprayer and well suited to the type of work I do,” he says. “There have been a few problems with the Topcon control system and the boom height sensors have yet to work, but I’m reasonably impressed so far.

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