Duster

duster

a cloth used for dusting furniture, etc.

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Duster 

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