Classifying – separating – and assorting solids – Stratifiers – Elements
Reexamination Certificate
2000-02-22
2001-09-25
Walsh, Donald P. (Department: 3653)
Classifying, separating, and assorting solids
Stratifiers
Elements
C209S172500, C209S492000, C209S493000, C209S460000, C209S501000, C209S494000
Reexamination Certificate
active
06293407
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention pertains generally to devices for separating items by introducing the items into a fluid flow path. This invention also pertains generally to devices and systems for separating debris from items. The preferred embodiments of the invention have specific relevance to apparatus for separating debris from produce, such as potatoes, sweet potatoes, sugar beets, carrots, and any other commodity or material having a specific gravity greater than one, the most preferred embodiments pertaining to—the separation of debris—e.g., vines, grass, defective potatoes, plastic, dirt, and/or rocks from potatoes. The invention can also be used to separate a variety of other product, such as apples, oranges, other citrus fruit and product having a specific gravity less than one.
2. Description of the Related Art
Typically, when potatoes or the like are gathered from a farm site, various debris is unavoidably collected along with the potatoes. The type of debris depends, in part, upon the soil and farm conditions; however, such debris typically includes one or more of the following: vines, grass, defective potatoes, plastic materials used in potato fields, dirt and/or rocks. Often, the ratio of debris to potatoes is on the order of about 1/3. Accordingly, separation of such debris is critical. When farmers sell such potatoes to end users—e.g., manufacturers of potato chips, french fries, and the like—such end users typically demand, that such potatoes be virtually free of such debris. A few items of debris in a single delivery can result in a lost sale and/or can even lead to the farmer's need to compensate the end user for costs related to such lost sale. As a result, considerable efforts are applied by farmers to remove such debris. This debris is usually removed manually. However, the amount of potatoes or the like processed is often a very large number. A farmer often must hire even about 30 people to work at the same time to separate unwanted debris from the potatoes.
Similar problems exist with other produce such as sugar beets, carrots, sweet potatoes and the like. There has been a need for an apparatus which can accurately separate debris from potatoes and the like. Existing systems which have been developed for the automation of debris elimination have a variety of problems—making their use less desirable, impracticable and/or impossible.
One known system is shown in U.S. Pat. No. 4,759,841 (Flodin). The '841 patent shows a density-current method and apparatus for separating produce, such as potatoes, from debris. In this system, an elongated tank has a water current directed from an inlet at one end wall. Products are conveyed into the tank by a conveyor adjacent to the inlet. As a result, the products introduced into the water stratify, due to their different densities. This device has a number of drawbacks, such as inability to handle a large quantity of produce at a single time, inability to maintain cleanliness of the water in the tank, inefficient separation capabilities and non-adaptability.
A variety of other systems are also known for the separation of various items in a fluid medium. However, all of the existing systems have substantial drawbacks and/or are inapplicable to certain uses contemplated by the present invention. There is still a great need for a device that will enable farmers to overcome the problems inherent with existing methods of removing debris from potatoes—which to this date, has largely been performed by substantial manual labor. In addition, there still remains a need for a permanently installed separation apparatus, such as at a processing plant which receives and processes potatoes and the like items.
SUMMARY OF THE INVENTION
The present invention overcomes the above and other problems in the existing devices and prior methods of product separation.
According to a first aspect of the present invention, a debris eliminating system is provided which includes: a) a tank for holding water; b) a system for circulating water across the tank from a first side to a second side and for returning at least a portion of the water from the second side back to the first side so that water generally continually flows across the tank; c) a pump for circulating the water across the tank; d) a medium density object collector within the tank; e) a light debris collector within the tank for receiving light debris which flows further downstream than the medium density objects; and f) a conveyor filter through which substantially all of the water in the tank is circulated, wherein the light debris is collected upon the conveyor filter and discharged out of the tank by the conveyor filter.
According to another aspect of the invention, the debris eliminating system further includes a high density object collector within the tank at a location upstream of both the medium density object collector and the light density object collector.
According to another aspect of the invention, the medium density object collector and the light debris collector within the tank include upwardly curved ducts.
According to another aspect of the invention, the upwardly curved ducts converge in a manner to cause the medium density objects and the light debris to be conveyed upwards by the water flow through the ducts.
According to another aspect of the invention, a receiving flume is located proximate the top of the tank for placing items to be separated into the tank, the receiving flume having a horizontal surface and a plurality of fingers at the output end of the horizontal surface which allow water to freely pass between the fingers while maintaining larger objects above the fingers.
According to another aspect of the invention, the medium density object collector includes a conveyor belt or chain which receives medium density objects and conveys such objects out of the tank.
According to another aspect of the invention, the conveyor filter includes a conveyor having cross bars which pass over a surface of the filter so as to draw debris off the filter and out of the tank.
According to a second aspect of the invention, an item separating system is provided which includes: a) a tank for holding water; b) a system for circulation of water from an output location in the tank through a duct and back to an input location to the tank so that water flows in a first direction across the tank; c) a pump for pumping and circulating the water through the duct; d) a medium density object collector within the tank; e) a light debris collector within the tank downstream of the medium density object collector; f) the light debris collector including a filter through which substantially all of the water in the tank is circulated. According to a further aspect of the invention, the item separating system is a debris eliminating system. According to a further aspect of the invention, the debris eliminating system further includes a high density object collector within the tank at a location upstream of both the medium density object collector and the light density object collector. According to a further aspect of the invention, the pump circulates 1000 to 2000 gallons of water through the system per minute per foot width. According to a further aspect of the invention, the system for circulating water includes a duct for circulating water and a flume for receiving water from the duct. According to a further aspect of the invention, the debris eliminating system as recited in claim
1
, wherein the system for circulating water includes a duct for circulating water and a discharge diffuser at the end of the duct. According to another aspect of the invention, the flume receives water from the duct at a level above the water line within the tank and directs the water in an opposite direction to the first direction, and wherein a redirecting baffle receives water from the flume and redirects the water so as to double back to flow in the first direction within the tank. According to a further aspect of the invention, the flume has a bottom
Recot Inc.
Rothwell Figg Ernst & Manbeck
Schlak Daniel K
Walsh Donald P.
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