There are a lot of sprayers available and choosing the right one for your needs is important. The type best suited will depend largely on the type of application, the site, frequency of use and operator experience.
The smallest sprayers are the trigger type and small handheld compression sprayers that hold about one litre of fluid. Sold in most hardware stores and generally deemed a domestic or DIY product, this design of sprayer can sometimes prove useful in the commercial world — and not necessarily for chemical application. They are particularly handy for freshening up displays or exhibits of plants with a mist of water and they can also be used for spot treating small, very localised weed problems on driveways, paths or patios.
Similarly, compression sprayers holding between three and eight litres of liquid, typically with a shoulder strap and a lance, can have a role in the professional workplace. It is not every situation that requires a knapsack full of herbicide or pesticide, so these handheld sprayers are ideal if working on beds and borders. Some have kits to convert them into irrigators for watering hanging baskets.
But it is the knapsack sprayer that is the mainstay of the professional industry, be it commercial or amenity. It is also the knapsack sprayer that, in the past, has had bad press. Problems such as splashback when filling, leaks and drips down the back, plus fatigue from carrying and operating the sprayer, meant many people loathed having to use them. Thankfully, better design and construction, industry regulations and operator training mean that knapsack models now give more accurate and safer applications.
Whatever the type of sprayer you are looking to buy, safety and strength are paramount. It should meet the requirements of British and European standards and the various parts of the sprayer must be well constructed. The parts — especially the hand lance, hoses, nozzle, lids and pumping lever — should fit together with seals in a way that eliminates leakage yet permits cleaning, maintenance and replacement when necessary.
The tank needs to be non-corrosive and should be impact resistant to withstand the knocks and bumps of being bounced around inside a van. A flat bottom is essential for stability when filling, and also for comfort. When choosing a knapsack sprayer, look for moulding so the tank fits nicely onto your back. There must be no opening below the liquid level and the inside should be smooth for easy cleaning and rinsing.
To reduce chemical spills, look for a sprayer with a wide-diameter filler hole. Check the basket filter or strainer inside — deep ones with mesh at the base and the sides are designed to reduce splashback to a minimum.
Knapsack sprayers are ideal when there is a lot of walking to be done between applications. But a full knapsack — with between 15 and 22 litres of solution — is soon going to tell on your back. Straps should be broad and well padded to help distribute the weight. They should also be non-absorbent. A waist strap will help take some of the weight off the shoulders.
Pumping the lever with one hand while holding the lance away from your body with the other is also tiring. A solution, especially for those likely to use knapsacks for hours at a time to control pavement and highway weeds, is to choose a model where the lever can be swapped from right- to left-handed pumping. But you should make sure that such a changeover is quick and easy. Motorised knapsack sprayers eliminate the need to pump altogether, though there will be the extra weight of the engine or battery to carry.
Hand lances should, ideally, be adjustable so that tall operators have no need to stoop when spraying. The trigger on the lance should be easy to use and the sprayer should come with a range of nozzles. Select the most suitable type and size of nozzle to ensure minimal drift and correct application rate for the product applied. Accessories such as hoods and shields may be useful, and make sure you find out about the availability of spare parts.
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