Conclusions - 2010
The results of this project have been extremely encouraging. Both patternators developed in the project outperformed the previously designed Cornell patternator. The large amount of uncollected spray material (82% to 87%) generated by the Cornell design could introduce errors in sprayer adjustment. On average, the new patternator designs represent an almost four fold increase in spray material captured versus the Cornell patternator. The efficiency of the Cornell patternator could be improved with a tighter mesh window screen. Fiberglass window screen of 18 x 16 mesh is commonly available and was used for the patternators in this project.
| Patternator | Recovery |
|---|---|
| Cornell | 13% - 18% |
| SARE | 62% - 63% |
| SARE with screens | 53% - 60% |
SARE patternator is recommended due to ease of construction and high performance.
Statistical analysis comparing the individual panels of each patternator show the SARE developed patternators are far superior to the Cornell patternator. Statistical significance was determined with Tukey's hsd test. With the Berthoud Saphirex discs the SARE patternator captured significantly more spray material than the Cornell patternator on all panels except the bottom panel. The same discs with the SARE WITH SCREENS patternator captured significantly more spray than the Cornell patternator on five of the seven panels. The TeeJet discs gave results similar to the Berthoud discs. The SARE patternator captured significantly more spray material than the Cornell patternator on all panels except the two bottom panels. The same discs with the SARE WITH SCREENS patternator also captured significantly more spray than the Cornell patternator on five of the seven panels.
The Cornell design of patternator with its screens allows a great deal of the spray to pass right through the patternator. This is easily visible while the patternator is being used. The amount of spray passing through the Cornell patternator is at its greatest when the spray is hitting perpendicular to the patternator at a 0 degree angle of incidence. This can be seen in the graph showing the results with the Berthoud discs. The amount of spray captured by the Cornell patternator on panel #3 is actually lower than the amount captured by panels #2 and #4. With the two SARE patternators the greatest amount of spray was captured on panel #3. As the angle of incidence increases, a lower percentage of water will pass through the Cornell patternator and the efficiency of the panels will increase.
Air velocity also comes into play with the patternators. The upper and lower panels of the Cornell patternator are a greater distance from the sprayer and would consequently have lower air velocities hitting them. For the panel that is directly opposite the sprayer, the higher velocity air stream helps to blow water through the screen before it has a chance to be collected in the channel at the bottom.
The modified Cornell patternator had a much lower cost than the previously developed Cornell patternator. In 2006, the Cornell patternator had a material cost of $489.28, while the modified Cornell patternator developed in this project had a total materials cost of $127.44 in 2010. The material cost of the SARE patternator totaled $93.44, below the targeted total costs of $100. Of the three patternators tested, the SARE patternator performed the best. Combining the statistical results of both spray discs for the SARE patternator, 79% of the panels captured spray amounts that were significantly greater than the modified Cornell patternator. All significant panels but one were at a 1% level of significance. From the results of this project, the SARE patternator is recommended as an efficient and low cost patternator that is easily constructed. This patternator will help famers reduce pesticide use and improve the profitability of their operation.