Technical
Rob Hayward
Rob Hayward is an export sales manager at Ransomes Jacobsen. He manages several dealerships in the UK and Sweden, with a special interest in sprayers, developed during his time as a greenkeeper. In this article, Rob discusses sprayers, the common causes of poor performance, and the technology surrounding sprayers today
A
sprayer will be a very familiar piece of equipment for many. Knapsack, tractor mounted or perhaps self‐propelled, it’s an essential piece of equipment for any fine turf facility. In this article, we look at sprayers in general, the common causes of poor performance, and the effect that advancements in technology will have on sprayers of the future.
A sprayer is fundamentally a delivery system for a liquid product. It can, with the correct nozzle, deliver either a contact product to the leaf, a systemic product to
the plant roots for uptake, or wetting agent to the soil.
The cost and complexity of these products is increasing all the time, as are the controls and legal restrictions associated with the delivery of pesticides and other products. Therefore, it’s important to understand how the sprayer works, and how, given the cost, legal and ethical considerations, to set‐up your unit for the best performance.
Operating systems
There is a wide range of sprayer options out there, from simple knapsacks, to tractor mounted units, utility vehicle mounted units and dedicated self‐propelled spray vehicles. All of these come with a range of operating systems and multiple feature options. Once you have decided on the type of sprayer, there are three main types of operating system to choose from:
Base models
The basic sprayers will have a manual pressure control valve and either levers or electric switches to activate the boom(s) depending on the size of the sprayer. These units often hit the cost requirement, but the very simple controls do mean the units must be accurately calibrated and carefully driven to achieve the desired application rate. Attaining a constant speed over undulating ground is not easy, so the errors can, and do, add up.
Mid-Range systems
Many operations have now moved to a mid‐ range sprayer, where the controller can measure and vary the flow rate to match the forward speed (within a certain range), and therefore deliver a consistent application rate (litres per hectare).
This is more expensive to buy, but a lot of the errors caused by poor speed control are removed by the variable flow rate and the controller. Providing you get the nozzle selection right, the controller should be able to handle the rest for you.
Top of the range units
There are fully computer driven sprayers with GPS speed measurement and the option of real‐time mapping of the target areas. There is also individual nozzle shut off, to prevent any overspray or overlapping. “Pulse width modulation” nozzles, mounted in pairs give such a wide range of application rates that once set‐up, the operator shouldn’t need to change the nozzle size again, and they always deliver a consistent application rate regardless of the changes to the forward speed.
So there really is something for everyone in the range of sprayers, and they all have one thing in common: nozzles!
Spray Nozzles
All sprayers deliver the liquid product through a spray nozzle. These are essential
PC JUNE/JULY 2018 I 129
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