1. Field of the Invention
The present invention relates to a system or station and method for cleaning pallets or the like. More particularly, this invention relates to a station and method for cleaning, decontaminating or otherwise refurbishing wooden pallets so that after processing they can be reused for various product shipping applications.
2. Description of Related Art
Several devices are known for cleaning pallets per se. For example, Herschberger U.S. Pat. No. 7,087,121 shows a rotary brush device (and method) for removing sawdust from the deck of a newly made, wooden pallet. Using only an upper and lower brush (and no additional side brushes), this device combines with compressed air to mostly remove left over sawdust from unused pallets.
Foster et al U.S. Pat. No. 6,129,099 uses a plurality of high pressure, rotating jet nozzles to clean articles including pallets. Optional air blowers may supplement the water washings performed by this apparatus.
In Whitehorn U.S. Pat. No. 5,446,942, individual pallets are steam cleaned with a plurality of spraying nozzles. Similarly, a heated, pressurized fluid is sprayed on mostly plastic pallets in the portable cleaning chamber of Dobson U.S. Pat. No. 5,372,153.
For the manufacture of concrete blocks in molds, flat steel pallets are used to hold the blocks for curing. To remove flash buildup from these pallets, Coggin et al U.S. Pat. No. 4,428,090 taught using a pallet scraper that includes blade protection should pallets accidentally travel in the wrong, i.e., reverse, direction through that cleaning/scraping system. This represented an improvement over the pallet cleaning machine of Frese U.S. Pat. No. 2,799,879. For the type of pallets used in concrete pipe manufacturing, Lang U.S. Pat. No. 3,849,820 taught engaging the outer rims with several rotatable brushes. Nine years earlier, Simmons U.S. Pat. No. 3,217,348 used a reciprocating scraper blade to accomplish a similar cleaning of concrete mold pallets.
There are numerous other disclosures for cleaning block mold (rather than standard wooden) pallets. Among them are Warsaw U.S. Pat. No. 2,752,621, Beals U.S. Pat. No. 2,724,137, Moore U.S. Pat. No. 2,637,057, Wellnitz U.S. Pat. No. 2,333,285 and Collins U.S. Pat. No. 1,045,677.
Still other known pallet cleaning methods employ significant quantities of water, often sprayed in combination with other liquid chemical treatments. The present invention manages to streamline the process of decontaminating used pallets while eliminating the need for using potentially harmful chemicals. Furthermore, this invention accomplishes its goal of wooden pallet “rehabilitation” at a drastically reduced energy consumption level when compared to other currently known methods.
It is an object of the present invention to provide a two-stage system for cleaning and/or refurbishing used pallets, especially wooden pallets. The first stage sends pallets along a conveyer into an area where a plurality of brushes directed from the top, bottom, and sides scour away surface debris from all pallet exteriors. A plurality of brushes scour debris from the top, bottom and sides to each pallet interior. Preferably, these brushes are treated with a non-stick coating, such as Teflon®, for preventing removed pallet debris from sticking to same. When not in use, these brushes may retract into ridged chambers from which removed pallet debris may be periodically removed. While the first stage is readied for processing its next used pallet, the first, fully scoured pallet is advanced to a germicidal stage or station for killing off any remaining bacteria, viruses, molds, etc. Preferably, that latter stage exposes the pallet exterior to ultraviolet light for a determined length of time. Should end use applications dictate, the inside pallet surface areas may be subjected to additional germicidal irradiation. The preferred method is waterless and requires no natural gas, applied detergents or other chemicals. It is also more energy efficient than today's known alternative means for pallet rehabilitation.
Other objects and features of the present invention will be obvious to those of skill in the art. It should be noted, however, that the drawings are designed for the purpose of illustration only and not as a definition of the limits of the instant invention, for which reference should be made to the claims appended hereto.
Further features, objectives and advantages of the present invention will become clearer when referring to the following detailed description of preferred embodiments made with reference to the accompanying drawings in which:
The system of this invention is used to clean, cleanse or rehabilitate multiple pallets that are conveyed or otherwise transported through its various stages or stations. Preferably, this system and the method of disinfecting that it employs refurbishes already made and used wooden pallets or “skids”. It is not intended to clean newly constructed pallets that have yet to be used.
Pallets made of softwoods are often considered expendable. They may be discarded as trash, along with wrapping elements, after the item being transported reaches its final destination. Such pallets typically permit lifting from only one or opposite ends. Hardwood pallets, capable of being lifted from all four sides, are costlier to make. Their construction can vary with end use, i.e., general non-food versus FDA-compliant, long term storage and possible chemical contacting. If exporting outside the U.S. is anticipated, still other rules will apply. The National Wooden Pallet & Container Association has developed a pallet design system (PDS) for generating the best options for a given product load.
The hardwood pallet most commonly made and sold measures 48 inches long by 40 inches wide by 5 inches deep. Known as the GMA or “grocery” pallet, it is used for nearly thirty percent (30%) of all domestic applications. While the system and method of this invention are intended to primarily disinfect this wooden pallet size for reuse, it is to be understood that reasonable and inexpensive modifications to same will allow the system to be used for still other wooden pallet shapes and sizes, and/or to rehabilitate-refurbish non-wooden alternatives including those pallets made of plastics, composites, metals and/or combinations of same.
Referring now to
In the preferred view of
The preferred embodiments of first stage area 20 are divided into regions for ease of description. It is to be understood, however, that the transitions between regions and/or their precise order, may vary with equipment availability and/or plant floor layouts. The first preferred embodiment of
In either arrangement, there is a first region for cleaning or brushing a top exterior of each pallet. In
In
In
The brushes used in accordance with this invention may be treated with a non-stick coating. A representative example is Teflon®, as made and sold by DuPont. When duly treated, the pallet debris these brushes are removing is less likely to stick to or in the brush body proper thereby reducing the possibility of transferring to other pallets passing through, or cross-contamination. It is further desired that when the brushes of this system are not “in use”, they can retract into their respective chambers, depicted as a ridged region “RR” about the lower left brush in
Ideally, much of the foregoing brushing or scouring should be conducted under a dust hood like item 88 in
In this second embodiment, the pallet interior top, bottom and side surfaces are next commonly cleaned by inserting into each interior of pallet “P” a plurality of indexed brush heads 85. Such brush heads are designed to slide along preset track heads for allowing left-to-right, and top-to-bottom cleaning to effect a near simultaneous cleansing of the pallet interiors per regions five through eight of first stage area 20.
After all first stage area regions are finished, a fully scoured (both inside and outside) pallet “P” advances on conveyor 140 to a second stage 30. There, at least the pallet exteriors are treated by exposure to a non-chemical, non-liquidous germicidal treatment. Preferably, this is accomplished with a brief but effective barrage of ultraviolet light within tunnel or chamber 100. A representative treatment chamber, about 48 inches high, made and sold by American Air & Water, Inc., includes several GML425 lamps that can deliver at least about 72 WVC watts to the system. The lamps in chamber 100 should be Teflon-coated and protected with custom guard rails on which pallets “P” will slide.
If a given reuse application for the treated pallet dictates, the inside surfaces may be optionally treated with their own UV light exposure. That may be accomplished by adding another conveyor stop mechanism, additional UV bulbs (at least four) and some servo drives for indexing these bulbs to the open side areas of each pallet to be treated. That will affect, if needed, an exposure to all scoured under side surface board areas.
The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative, not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.