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a machine or device for applying powdered dry pesticides to crops to protect them against pests and disease. Tractor-mounted or knapsack manual dusters are used, depending on conditions.
Tractor-mounted dusters are used to dust field crops, orchards, vineyards, and forest tracts. The working members are driven by a power takeoff shaft from the tractor engine. The operating width depends on the design of the duster; for vineyards it covers two to four rows, and for field crops, 10–100 m. Rated performance is from 3.5–5.0 to 30–64 hectares per hour.
|Table 1. Main drying oils and their uses|
|1 mixture of polymerized and dehydrated oils is used *White spirit is the solvent ‘Content of alkyd resin, which has a fat content of 59–65%|
|Name||Type of oil||Processing method||Oil content (percent)||Uses|
|Natural.............||Drying||Partial polymerization||100||Preparation of primers, putty, oil paints (concentrated and thinned to working consistency); treatment of wood surfaces and other porous materials|
|Compound...........||Drying or semidrying||Polymerization and dehydration1||70–732||Preparation of concentrated oil paints|
|Seminatural (for example, oxole) ............||Drying orsemidrying||Polymerization||50–552||Dilution of concentrated oil paints to working consistency|
|Alkyd (glyptal, pentaglyptal).||Drying||–||502,3||Preparation of oil paints (concentrated and thinned to working consistency)|
Knapsack dusters are used to treat vineyards, young fruit plantings, berry patches, vegetable fields, and other crops on small and inaccessible plots. The main units of such a duster are a tank with a feed device, a fan with a drive handle, and a tube with a spray nozzle. It has shoulder straps for carrying. Some knapsack dusters have a bellows instead of a fan for spraying the pesticide.
All dusters have the same principle of operation. The powder is fed from the bin or tank into a mixing chamber, and then it is forced by a stream of air created by the fan or bellows through the spray nozzle and out onto the plants.
G. P. SHAMAEV