Classifying – separating – and assorting solids – Sorting special items – and certain methods and apparatus for... – Separating means
Reexamination Certificate
2000-01-18
2001-07-24
Walsh, Donald P. (Department: 3653)
Classifying, separating, and assorting solids
Sorting special items, and certain methods and apparatus for...
Separating means
C209S659000, C209S660000, C209S667000, C209S670000
Reexamination Certificate
active
06264043
ABSTRACT:
BACKGROUND OF THE INVENTION
The following invention relates to a sizing apparatus for sizing food product such as potatoes.
Food product such as potatoes is frequently processed so that similar sized pieces of product are grouped together. Thus, part of the task of preparing food product for further processing or distribution is to size the product properly so that large pieces of product are not mixed in with smaller ones and vice-versa. In the past, various types of graders have been used to properly size food products. An example of such a device is a roll size grader manufactured by Welliver Metall Products Corporation of Salem, Oreg.
The Welliver grader used a sizing table which employed conically shaped rollers which had a gradual taper from the input end of the roller of the table to the output end. This device is illustrated in FIG.
1
. As can be seen from the figure, a set of tapered parallel rollers
2
extends from an input end of the table to an output end. Vanes in the form of spiral threads are included on every other roller
4
so that when product is deposited at the input end of the table the threads push it forward toward the output end, that is, from right to left. With the taper of the rollers becoming smaller from the input end to the output end, smaller food product near the input end then larger food product drops between the rollers to the conveyor belts
6
below. The problem with this size grader table is that it is incapable of grading food product in two dimensions. For example with potatoes, long thin potatoes will slip through the portion of the size grader intended only for smaller potatoes. Long thin potatoes do not process well into french fries and it would be desirable to remove these potatoes so that they are not mixed in with the other grades of product which have a more symmetrical shape.
Another problem with sizing tables having fixed sizing apertures is that they do not allow for variations in product or changes in the sizes of product. Product like potatoes can vary in size distribution depending upon agricultural factors such as rainfall in any given year. Thus, one year's harvest may yield large potatoes while the size distribution may be smaller the following year. Sizing tables such as the Welliver are fixed, however, and do not accommodate changes in product size distribution or even changes in the types of products processed.
BRIEF SUMMARY OF THE INVENTION
The present invention provides a sizing apparatus for sorting product according to its size and comprises a frame which supports a plurality of horizontally extending parallel rotary spindles. A first group of the spindles supports tapered rollers while a second group of the spindles interposed in an alternating fashion with the first group includes variable pitch augurs. A motor imparts rotary motion to both groups of spindles.
The rollers are tapered so that their diameters gradually decrease from the input end of the sizer to the output end. The augurs which have deep helical vanes so as to present a two dimensional aperture relative to the rollers have a pitch which increases progressively from the input end to the output end of the sizer. The pitch of the augurs can be made adjustable because the augurs are constructed in segments which fit together when each segment is placed on a rotating spindle. Each segment of the variable pitch augurs comprises a mounting portion which has an aperture for receiving a spindle shaft and a generally helically shaped blade portion where the blade portion of each segment extends for a radial length of between 90 degrees and 180 degrees. Preferably, the segments are 120 degree segments.
Since the augurs are constructed in segments, the pitch is continuously variable. The user may selectively construct augurs using segments of varying pitch to arrive at an overall sizing for the augur that can accommodate differing size distribution of the same product or different product altogether. The sizing table can therefore be changed or customized for product of variable size distribution.
The tapered rollers may also be adjusted for size and may be comprised of a set of frusto-conical segments which abut one another when they are threaded onto the spindles. The sizes of these rollers are selectively variable so that rollers may also be customized to complement the variations in the pitch of the augurs.
The augurs are situated adjacent the rollers and the space between the augur and each next adjacent roller defines an aperture through which only properly sized product can slip. Long skinny products cannot slip down into the space so defined because the pitch of the augurs is too fine near the input end even though the diameter of some of the product would be such that it could fit through these input openings. However, it is only near the output end that the pitch of the augurs becomes long enough to allow longer pieces of product (that is, longer along the major axis of the product) to slip between the threads of the augur and onto an appropriate conveyor or bin situated below the sizer table.
Thus, as the augurs turn, the food product is moved from one end of the sizing table to the other end, and properly sized product is allowed to drop at the appropriate point onto conveyors or bins located beneath the table which are grouped according to size.
Beauchaine Mark J.
Chernoff, Vilhauer, McLlung & Stenzel, LLP
Key Technology Inc.
Walsh Donald P.
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