1. Field of the Invention
This invention relates to a spray shield for use on crop spraying equipment.
The conventional crop or field sprayer includes a boom assembly attached to a trailer and extending outwardly from both sides thereof in the spraying position. The boom assembly includes an elongated pipe or boom carrying a plurality of spaced apart nozzles, each having a spray tip for dispensing liquid. The currently preferred flat fan spray tip distributes the liquid in an elliptical pattern, the major axis of which is inclined with respect to the axis of the boom. When a plurality of such tips are spaced equidistant apart along the length of the boom, the spray patterns formed by the tips overlap but do not interfere with each other. Because the patterns flare or fan out, overlap without interfering with each other and are spaced equidistant apart, the spray can be distributed along the length of the boom with a plus or minus 5% variation in spray tip output.
On the other hand, because the droplets are so small, they can readily be deflected from their normal pattern by a wind of 10 km/hr or greater. Spray distribution can easily be disrupted to reach unacceptable levels, i.e. an unacceptably large crop area is missed by the spray. Because of the relatively short spraying season, it is almost inevitable that spraying must sometimes be done during unfavorable windy conditions.
2. Discussion of the Prior Art
One solution to the above mentioned problem is to provide a spray cover or hood over all or most of the boom structure. Such solution is proposed, for example by U.S. Pat. No. 3,512,714, which issued to M. E. Phelps et al on May 29, 1970. The Phelps et al and other commercially available spray hoods either contact or come close to the top of the crop being sprayed to ensure minimal wind interference with the minute droplets. Thus, such devices possess the disadvantages that they are large, cumbersome and expensive to produce. Moreover, the hoods extend so far from the boom that the spray nozzles and tips are not readily accessible, and there is no way of knowing when a nozzle or tip becomes plugged because the spray patterns are not visible.
The object of the present invention is to solve the above-mentioned problems by providing a relatively simple, economical spray shield, which substantially reduces wind interference with a spray pattern while still permitting access to the spray nozzle or tip.