The present invention relates generally to devices and methods for processing harvested nuts and more particularly to a system and method for processing harvested walnuts that includes a device and step for separating walnuts without hulls from those with hulls prior to the step for removing hulls from walnuts.
There are numerous devices, systems and methods that relate generally to the process of separating debris from harvested nuts and cracked nuts from un-cracked nuts and the meat of the nuts from their shells.
Devices have been developed that provide for the separation of harvested nuts from debris: U.S. Pat. Nos. 4,927,030, (sorting sticks, weeds and other debris from peanuts and sorts peanuts into size categories), 4,535,894, (separating peanuts from vines and debris), 4,364,222, (separating nuts from orchard trash in a windrow), 4,194,346, (separating fallen nuts from leaves and other foreign matter) and 2,762,506, (separating nuts from debris and other foreign matter).
There are devices and systems for cracking nuts and removing nuts from the shell: U.S. Pat. Nos. 5,404,809, (nut shelling device), 5,296,248, (cracking walnuts by subjecting the shell to opposed compressive forces) and 3,662,799, (cracking nuts, without crushing the kernels).
Similarly, there are devices and methods for separating partially cracked nuts from cracked nuts. U.S. Pat. Nos. 6,902,067, (removing debris including empty shells and sorting out unacceptable in-shell nuts), 6,824,804, (pecan processing method and system wherein pecan parts that fall beneath the cracker are conveyed to an air separation device that removes dust and shells for disposal), 6,527,124, (separating blank pistachio shells and other debris from pistachio nuts) and 5,879,734, (nuts and nut parts created in the cracker are separated in successive steps by width and thickness).
In addition there are various illustrations of the concept of combining various functions or steps in a system: U.S. Pat. Nos. 6,527,124, (combines a flotation tank, a weir and discharge channel, a conveyor within the flotation tank and a pair of counter-rotating rollers for squeezing floating items towards the weir and discharge channel) and 5,467,700, (a device for cleaning, shelling, and sizing nuts in a single step).
There are unique challenges presented by the processing of harvested walnuts that involve removal and handling of the hulls that surround the harvested nut. Typically, the harvested walnuts or “field run” contains leaves, rocks, dirt, sticks, walnuts and other matter. Some of the harvested walnuts have hulls, some do not. According to current practices because some harvested walnuts have hulls, all harvested walnuts are sent through a huller for processing. The time and therefore the cost associated with processing walnuts are affected by this fact.
Advantage may be found in providing a device for processing harvested walnuts that sorts walnuts with hulls from those that have no hulls and diverts those walnuts that have no hulls in a manner that circumvents the huller. Similarly, advantage may be found in providing a method for processing harvested walnuts that includes the step of sorting walnuts with hulls from those that have no hulls and diverting those walnuts that have no hulls in a manner that circumvents a hulling step.
Sorting harvested walnuts without hulls for bypass from those with hulls would increase the volume per hour that the hulling plant can produce while reducing wear/maintenance on the huller. Sorting harvested walnuts as described will also improve overall product quality by eliminating walnut damage that occurs within the huller to those walnuts that are selected for bypass.
One object of the present invention therefore is to provide a device for processing harvested walnuts that sorts walnuts with hulls from those that have no hulls and diverts those walnuts that have no hulls in a manner that circumvents the huller. Another object of the invention is to provide a method for processing harvested walnuts that includes the steps of sorting walnuts with hulls from those that have no hulls and diverting those walnuts that have no hulls in a manner that circumvents a hulling step.
The present invention is directed to a system and method for processing harvested walnuts that includes a walnut separator for separating walnuts without hulls from walnuts with hulls prior to a hulling process in order to increase productivity of the huller. A huller by-pass system conveys walnuts without hulls to post-hulling processing. In a preferred embodiment of the invention, a walnut separator includes an optical sensor positioned to scan harvested walnuts. A controller connected to the optical sensor processes input from the optical sensor and selectively actuates a walnut selection or ejection device to select or eject a walnut from a conveyance device. Those walnuts that include hulls are conveyed to the huller, while those walnuts that are free of the hull are diverted for conveyance to the washer and other downstream processing. Alternately the walnut separator may include a mesh, screen or grate having a selected interval between mesh, screen or grate elements that permit walnuts without hulls to pass through the screen and prohibit walnuts with hulls and therefore a larger diameter, to pass through the screen.
The present invention is also directed to a method for separating walnuts with hulls from those that do not have hulls. In a preferred embodiment of the method walnuts without hulls are diverted from a conveyance of walnuts for separate conveyance to a downstream processing step while walnuts with hulls are diverted for separate conveyance to the huller.
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In a preferred embodiment, pre-cleaner 12 includes a rotary cage or a rod type conveyor/elevator that functions to drop out loose hulls and small rocks or dirt clods that are contained in “field run” harvested walnuts H. The action of pre-cleaner 12 also knocks some hulls off of harvested walnuts H before they advance to float tank 15. Following pre-cleaner 12, harvested walnuts H are dropped into float tank 15, which is filled with water. Walnuts being buoyant float to the top of float tank 15 and are conveyed into walnut separator 20 while rocks and dirt, which would cause damage and wear to huller 35, drop to the bottom of float tank 15 and are removed from the system.
Walnut separator 20 includes means for separating walnuts with hulls from walnuts without hulls separating and diverting those walnuts without hulls from the flow of harvested walnuts H through system 10 for processing harvested walnuts. In a preferred embodiment, walnuts with hulls are separated from walnuts without hulls on the basis of color. In an alternate embodiment, walnuts with hulls are separated from walnuts without hulls on the basis of size. Those walnuts without hulls WO are directed to huller by-pass system 30 and ultimately to a post-hulling process, in this case, washer 51. Those walnuts with hulls W are directed through huller 35 where the hulls are removed. Walnuts without hulls that were diverted around huller 35 and those walnuts that have passed through huller 35 are discharged from discharge 40 into washer 51. Washer 51 includes a rotary cage or rod conveyor. Walnuts without hulls that were diverted around huller 35 and those walnuts that have passed through huller 35 are co-mingled in washer 51 and washed to remove dirt, loose hulls and debris.
Post-wash processing 55 includes final separating and sorting to remove blank or shriveled walnuts and walnuts that still have some hull left on them. Post-wash processing 55 may also include a visual inspection, (not shown), before continuing on to a drying process, (not shown). After walnuts are dried to the desired moisture content the nuts are ready for post-drying processing, packaging and sale.
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While the invention has been described in connection with the preferred embodiment, it is not intended to limit the scope of the invention to the particular form set forth, but, on the contrary, it is intended to cover such alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.