Patternator Testing - 2012
Our vineyard sprayer used in the project is a three point hitch Berthoud MGP 360 with torex nozzles purchased in 1975. The tractor utilized to operate the sprayer is an Oliver Super 55. Tractor PTO was set to 450 RPM using an ES 332 laser tachometer for all tests. At this RPM the sprayer pressure was set at 70 PSI. The nozzles utilized in the sprayer were Berthoud Saphirex 10 discs. The disc orifice diameter was checked with a digital caliper accurate to 0.0005 inches. The Berthoud Saphirex 10 discs had an orifice diameter of 0.033 inches.
The Berthoud 360 MPG sprayer has a total of 10 nozzles with five on each side. When spraying in our vineyard, once the vines have reached the top wire at 6 feet, only three nozzles per side are opened. The top and bottom nozzles are not utilized. For all testing of the patternators, the same setup was used. Only the nozzles on the left side of the sprayer were utilized during testing in 2012. In 2010 the right side of the sprayer was used.
A total of four paper patternators were constructed. The four paper patterntors were placed about 24 feet apart in a straight line. Each patternator had one type of paper. Four different papers were used in each test. A total of four replicates were done for each paper. With four different possible locations for a patternator during the testing, each type of paper was tested once at each of the four patternator locations.
For testing the paper patternators, 10 gallons of water and the proper amount of dye was added to the sprayer's tank. For proper color intensity 40 ml of the red food coloring per gallon of water was required. The blue turf spray pattern indicator required only 20 ml per gallon of water. The Berthoud 360 MPG has a 75 gallon tank. The height of the sprayer above the ground remained constant throughout all testing. The tractor was started 50 feet before the first paper patternator in third gear and with the left side nozzles of the sprayer open. Testing should be done on level ground at the same speed used when spraying.
Testing paper patternators
1st test The blue spray pattern indicator, Terramark SPI, was tested with four different papers;Office Max professional grade matte photo paper, semi-gloss photo paper, gloss photo paper and water sensitive papers. The Office Max papers were cut into 4”x6” paper cards and placed on the patternator with the 6” side being vertical. Water sensitive papers where attached with the 3” side being vertical. Seven cards were attached to each patternator at 1,5, 2.5, 3.5, 4.5, 5.5, 6.5 and 7.5 feet on center above the ground. All papers were attached with push pins, one at the top and one at the bottom.
2nd test Shank's red food coloring was used in the second test instead of the blue indicator. All other parameters remained the same as in the first test.
3rd test Red food coloring was used in the third test. The same type of papers were repeated, but the size and number of the cards was changed. Cards made of the Office Max professional grade photo papers were reduced in size to 3”x4” with the 4” side being vertical. Instead of just seven cards, fourteen cards were attached to the patternators at 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0 and 7.5 feet on center above the ground.
4th test Red food coloring was used in the fourth test, but two new papers were introduced. Fourteen 3” x 4” cards with the same placement as in the third test were used on each patternator. Gloss and matte OfficeMax professional grade photo papers were repeated. The new papers introduced were Hewlett-Packard Everyday gloss and Premium matte.
After each replicate in each test the cards were placed in resealable plastic bags. Each of the cards was later scanned on a Canon LiDE 200 scanner. An image analysis software program written in C was developed to interpret scanned photographic printer paper or water sensitive papers. Part of the image analysis software is a scanning program that allows multiple cards to be scanned simultaneously with Linux. If Mac or Windows are used the scanner's program must be used for scanning the cards. The image analysis program for interpreting the cards has cross platform capabilities with Windows, Mac and OSX and is open source. The image analysis program measures percent coverage of the spray on each card, droplet density in droplets/cm² and droplet size in microns (μm). The droplet size is measured at the volume median diameter (VMD or Dv0.5) or the size at which 50% of the volume is in larger droplets and 50% of the volume is in smaller droplets. Results were interpreted with both the image analysis program developed in this project (NESareScan) and the USDA program DepositScan, which was developed exclusively for water sensitive paper.
Statistical analysis of the results was done using the online site vassarstats.net. Depending on the number of variables being tested either a two-tailed t test for independent samples or a one-way analysis of variance (ANOVA) with Tukey's hsd test were run.