- leakages.
Leakages of knapsack sprayers remain a single most important problem in crop application procedures.Tank lids, triggers, hoses and their attachment points must all be effective at controlling leaks; under pressure and when the knapsack sprayer is inclined, horizontal or even vertical.
2. Safety and comfort.
Comfort,safety and convenience while carrying a sprayer is a key check point. Check to establish it has a lifting point[s] and if fully loaded can be readily carried. Straps and their fixing points are also critical. Wrong straps may break,become loose, or absorb spray solution. It should have a waist belt to both secure the sprayer in use and stabilise it when pumping. The knapsack sprayer should be economically designed to align with the user’s back for friendly usage.
3.The sprayer should be filled without spillage and filter out debris that can clog the spray line and nozzle.
Knapsack sprayers should be filled with spray solution quickly [ within 60 seconds] without excessive splash or spill and with adequate filtration.
The tank opening and the filter should be wide enough to ease the filling up.
4. knapsack stability on the ground.
Knapsack sprayers must not fall over when not in use but placed on uneven level ground. weight distribution and design especially of its base ensures stability. Nozzles are normally clogged and lances damaged on sprayers not in use if there is no parking device for the lance.
5.Adequate filtration.
Poor filtration will cause nozzles to be blocked; cause field loses and compromise safety. Tank filters/strainers must be fitted to trap debris when sprayer is being loaded. There must be a pressure filter to protect the shut-off valve in the lance and a filter behind the nozzle. All these filters must be cleaned as and when necessary.
6. Tank content gauge must be appropriate and readable.
A content gauge is critical to accuracy of spraying and minimising any surplus spray liquid.The gauge must show spray liquids clearly and the design must allow adequate spare tank capacity [head room] when filled to the rated maximum. These free space allows for easy physical agitation inside the tank.
7.Adequate pressure and flow rate.
Flow rate by the nozzle[s] must be within the range specified by its manufacturer. It should vary [within a comfortable pumping frequency range] to meet your spraying needs.A Lance fitted with a pressure gauge and a graduated Jug could be used for calibration evaluation purpose.
8. knapsack sprayer be cleaned after use with ease.
Chemical residual spray deposits are a threat to your safety, the next crop sprayed and the environment. The sprayers tank must have smooth surfaces both inside and outside. There should not be any liquid trapping points on the sprayer except in the tank sump. The knapsack sprayer must be able to expel out all the prepared solution from its tank.
9.The sprayer must be robust.
Knapsack sprayers are expected to suffer some shocks in normal use and so they must be capable of withstanding reasonable impact. This impact is tested in a controlled environment to check if the components will withstand such shock and more so allow their continued safe use. The sprayer design should withstand reasonable impact.
10. Knapsack sprayer weight.
Different manufacturers will produce knapsack sprayers of different weights even when the volume and materials are the same. They range from a net weight of 2.2 kg to 6 kg. The difference in weight is meant to dictate the market prices. It is obvious that the heavier the better the quality. Gullible customers will only consider the price but not the density of the materials used.