Giwa Knapsack Sprayer…
A knapsack is a type of sprayer that disperses liquid through a hand-held nozzle that is attached to a pressurized reservoir carried on the operators back. Knapsack sprayers can be used to apply liquids such as fertilizers, herbicides and fungicides.
Functioning and design
A manual knapsack sprayer basically consists of a tank for holding a liquid insecticide formulation, which can be pressurized by means of a hand pump attached to it. The compressed air forces the liquid from the tank via a hose with a cut-off valve, a lance and a nozzle.
Parts and functions of Giwa Knapsack Sprayer
- The tank itself is usually made of stainless steel. Most tanks have four openings on top: a large one for filling, fitted with a removable cover; and openings for the air pump, discharge system and pressure gauge.
- The tank cover consists of: (1) a rubber gasket; (2) a handle; (3) a pressure-release valve, operated by hand or by giving the handle a quarter turn; (4) a chain to prevent the cover from being lost.
- An air pressure gauge is used to measure pressure in the tank.
- The shoulder strap should be wide enough to prevent it from cutting into the shoulder of the person using the sprayer. It is fastened to the tank with steel buckles. On large tanks it is adjustable.
- When the tank is not in use, the spray lance is held in a bracket and nozzle cup, which protects the nozzle from damage.
Inspect the tank at regular intervals, and replace any worn or damaged part. Inspect the lip of the pump cylinder for cracks that could cause the tank to lose pressure. Check the rubber hose for cracks and weak spots. After some time the hose becomes weakened near the point of attachment to the spray-can or cut-off valve. The weak part should then be cut off and the hose remounted. Put a few drops of clean oil on the plunger cup leather to keep the pump cylinder lubricated and to ensure sufficient pressure. Replace the leather if damaged.
Nozzle tips erode during spraying. They should be replaced when worn. An eroded orifice causes an increase in the amount of pesticide delivered. The discharge rate should be measured from time to time by qualified personnel. A simple method is to spray a suspension on to a dark surface: irregularities in the swath indicate that the nozzle tip needs to be replaced.