The DBR harvest-assist system continues to be refined with commercialization in mind.
The decelerator has a large wheel inside with foam wedges to remove apples from the vacuum environment. Large elephant ears of foam gently distribute apples in the bin.
Photo by Melissa Hansen
After five weeks of testing in Washington State apple orchards last fall, the DBR harvest-assist system has been extensively modified for further tests this season in preparation for commercialization in 2013.
The system, developed by DBR Conveyor Concepts in Michigan, is on a platform and has four flexible tubes into which workers place apples as they pick them. The apples are transported through the tubes by vacuum into a bin on the platform. A straddle trailer at the back carries empty bins that are loaded onto the system as full bins are discharged in the row.
Mike Rasch, a partner in DBR, believes that a 50 percent increase in efficiency is possible, compared with traditional apple picking from ladders. In a fruiting wall system, the gain in efficiency could be 80 percent or more.
Karen Lewis, Washington State University extension tree fruit specialist, who has been testing a prototype built for Washington conditions, said last year’s trials focused primarily on how to reduce bruising to the 5 percent tolerance level. The harvesting system was tested with many different apple varieties, and an Impact Recording Device was used to measure impacts as it traveled through the system. The IRD showed that impacts were highest in the machine’s tubes that carry apples up to the platform, though not all the impacts caused damage. Speed and vacuum power affect the amount of impact.
A comparison of Fuji apples picked with workers using the harvesting system versus workers using ladders showed that there was bruising of fruit even when it was harvested in the traditional manner, Lewis reported to the Washington Tree Fruit Research Commission.
DBR field validation work is supported by the Comprehensive Automation for Specialty Crops project, in which she is a cooperator. Equipment costs for the DBR 2011 prototype that was built to Washington specifications were shared by CASC and the Washington Tree Fruit Research Commission.
Rasch told the Good Fruit Grower that he and his colleagues have made a number of modifications to the system since last season. These include:
- A self-leveling trailer to ensure that the bins are evenly filled with fruit, even when the system operates on slopes. The platforms will stay perpendicular to the trees, rather than the ground, helping with the positioning and access to the tree and fruit.
- A shelf above the elephant ears in the bin filler to ensure even filling of the bins even when the volume of fruit being picked varies from one side of the row to the other, or when picking outside rows.
- LED lighting, so that the system can be used for two shifts per day. Rasch said LED lighting is close to natural light and doesn’t cast shadows, and also has a low amp draw.
- A telescoping tongue between the tractor and the platform that can be retracted when turning rows.
- A remote steer/shuttle shift system on the tractor that can be operated from the platform to eliminate the need for a driver in the row, and a creep gear so that the tractor can move at about 0.2 miles per hour.
- Replacement of the safety rail with harnesses, which workers in Washington are more accustomed to.
Rasch said the system compared favorably with hand picking in terms of the quality of the fruit last season, but modifications have also been made to the fruit handling aspect. Each of the system’s four tubes can handle apples at a rate of up to two per second.
In August, the system will be tested in processing peach orchards in California. In late August and early September, it will be tested in California pear orchards. From the second week of September until the end of the season, it will be tested with apples and pears in Washington on more sloped terrain than last year.
Rasch said the system was designed to handle any round fruit or vegetable that’s not larger than the 4.5-inch diameter of the tube holes. However, it probably won’t be suitable for picking fresh peaches because friction between the fruit and the tubes removes the fuzz.
It has already been tested on Asian and European pears. If the European pears are oriented correctly, there seems to be no problem, but he’s not sure how well it would work if pears were put into the tube stem first.
“I think it’s all doable,” he said, “ But it’s going to be a learning curve. I think it will be a landmark year to get it out and get some time on it.”
Another model of the system will be tested in Michigan this season. Though the state only has between 10 and 15 percent of a full apple crop, this will be a good season to test it, Rasch said, because all the crop is in the tops of the trees.
“I think it will really shine this year for that reason, but we won’t get the efficiency on it because of the limited crop.”
Return on investment
Rasch said more refinements might be made before the system goes on sale in 2013 at an estimated cost of between $85,000 and $95,000. The cost does not include a tractor to pull it. Phil Brown Welding in Michigan will manufacture many of the trailer and platform components, and DBR Conveyor Concepts will manufacture the vacuum and other components of the system.
Rasch expects the grower’s return on investment to be good. The system is designed so that the harvesting part can be separated and the platform used year round for such jobs as pruning, thinning, trellis tying, and hanging of pheromone dispensers. “It’s the whole gamut of things a grower has to do in the tops of the trees,” Rasch said.
The partnership has already been contacted by interested potential buyers both in the United States and abroad, he said. “The interest is there. We’re excited about where it’s going, and we feel good about what we’ve achieved so far.”
Collaboration with the Washington tree fruit industry, the Michigan Apple Committee, Pennsylvania State University, and the CASC project has helped move the project along more quickly, he said.
With labor availability becoming an increasing concern, Rasch senses a greater willingness among growers to consider mechanization. “Labor is an issue, and the industry seems to have turned the corner towards looking at mechanization. Labor is really going to dictate the need for it.”