Patternators Developed - 2010
Modified Cornell Patternator
The first part of this project was to develop a much lower cost and easier to construct Cornell type patternator. The Cornell patternator utilizes window screen to collect the spray generated by an airblast sprayer and the SARE modified Cornell design also utilizes the same material. Fiberglass window screen of 18 x 16 mesh was used for the patternator. All patternators built for this project are based on multiple panels with a standard size of 3 feet wide by 1 foot tall. A standard size panel allows for test results of the various designs to be compared statistically. The panel size was selected because it captured a majority of the spray and was not too large to be cumbersome.
All materials for the patternators were purchased at large national home improvement stores and farm supply stores.
Parts and instructions are for building an 8 foot tall vertical patternator for vineyard use. It is divided into numerous sections that allow the user to quantify the amount of spray in each section. This design divides the patternator into seven sections of one foot by three feet. If a taller patternator is needed the design can be extended with more panels.
Materials for a modified Cornell patternator
| Item | Count | per piece | price |
|---|---|---|---|
| window screen frame sections (7 feet/section) | 8 | $3.79 | $30.32 |
| plastic corners for frames | 7 | $1.29 | $9.03 |
| 25' spline (.160 inches) for frames | 2 | $3.49 | $6.98 |
| fiberglass window screen roll 36” x 25' | 1 | $12.57 | |
| screen tool for applying spline | 1 | $4.49 | |
| 5/8” J channel for vinyl siding (12.5 feet/section) | 3 | $6.17 | $18.51 |
| screw hooks 1.75 inches long | 14 | $5.37 | |
| deck screws ($2.99/lb.) 8-2” - #6, 4-2.5”- #8 | 1 | $0.24 | |
| machine screws 14-3/4”#8-32, 6-1 ¼”#8-32, nuts 26#8-32, washers 26#8, lock washers 20#8 | 1 | $8.92 | |
| 3/16” aluminum pop rivets, grip 1/4” | 1 | $5.19 | |
| 2”x4”x8' wood stud | 2 | $2.25 | $4.50 |
| 1”x3”x8' wood furring strip | 1 | $1.48 | |
| steel T posts 6' each | 2 | $4.45 | $8.90 |
| wood blocks – cut from a 2” x 4”, 3.5” x 3.5” | 2 | $1.80 | |
| large plastic syringe (60 ml) from farm supply store-for animal injections | 1 | $1.79 | |
| silicon caulk | 1 | $4.97 | |
| rubber bands | 1 | $2.49 | |
| string | 1 | ||
| baler twine or some rope | 1 | ||
| reused plastic containers or cans | 7 | ||
| 1' long rod or stick | 1 | ||
| Total | $127.55 |
Instructions for constructing a modified Cornell patternator
Click any image for a larger version.
Screens
- Construct seven identical window screens of 1' by 3' using instructions from hardware store.
- Cut J channel into 40.5” long sections and remove lip from low side, leaving it about 3/4” high along the front side. A tin snips works well to cut the J channel.
- All J channels must be closed on both ends. Fold in 3/4” of the J channel to form an end and secure with a pop rivet, screw or nut and bolt. A 3/16” pop rivet works well. Seal the ends with silicone caulk. Drill a 1/2” hole at the same end of all the J channels. Make up seven identical J channels.
- At the end of the J channel with the 1/2” hole, about 1/4” from the end, cut about an 1/8” wide slot on both sides of the J channel. The slots should end about 1/2” from the bottom. A container with a string will be suspended from the slots to catch the water running from the J channel.
- Place a screen section in the J channel and secure the bottom of the screen to the J channel with two 3/4” #8-32 machine screws, washers and nuts. The screen should be positioned very close to the end of the J channel opposite the hole. The J channel should extend about 2.25 inches from the screen on the other end with the 1/2” hole.
- Drill a 3/16” hole through the vertical side of six of the screen frames. The hole will be on the same side as the 1/2” hole in the J channel and about 4.5” from the top of the frame. A bolt will pass through this hole to secure a rubber band.
Frame
- Construct a frame with the 2x4's and furring strip. The 2x4's should be around 20 inches apart on center with the 4” side to the front and back. Secure the proper length of the furring strip to the top and center of the 2x4's with 2” deck screws.
- Prepare two square blocks from 2x4's. Cut about a 1/2” deep and 1/2” wide channel in the middle along one long side of the block. Attach the blocks with 2.5” deck screws to each 2x4 support about 2.5 feet from the bottom. The slot should be perpendicular to the length of the 2x4 and against the 2x4.
Assembly
- Drill two 3/16” holes through the top frame of each screen section. The holes should be about 20” apart so the screen section will be centered on the 2x4 frame.
- Place the first screen section, without a rubber band hole in the side of the frame, at the top of the wood frame.
- With a screen section that is three feet wide, there should be a 3/4” drop (1.2 degrees) from one end to the other end of the screen section. Mark the 2x4's for placement of the screw hooks. If the 2x4's are 20” apart on center, the drop will be 7/16” on the center of the 2x4's.
- Hang the first screen frame on the hooks and repeat the procedure for each screen.
- Place 1 ¼” machine screws through the holes in the side frames of the screen sections. About a 1/4” of the machine screws should extend beyond the nuts and washers on each side of the frame.
- Hammer the two T posts in the ground about 1.5 feet deep and 20 inches apart. The patternator will held to the posts with ropes or twine placed through the slots in the wood blocks.
- Hang a container from the end of each J channel. Polyethylene terephthalate (01, PET or PETE) sports drink containers work well.
- Secure the containers to the machine screws on the screen frames with the rubber bands.
- Secure the bottom container with a rubber band to a rod or stick placed in the ground.
Measuring
- Plug the tip of the plastic syringe body with silicone caulk.
- After collecting spray, the contents of the containers can be measured with the large syringe or the depth can be measured with a ruler.
- Important: To avoid the possibility of pesticide contamination, all measuring devices and containers should be dedicated for use only with the patternator. Use clean water only in your sprayer when testing with a patternator. Do not use a pesticide mixture.