Cleaning and liquid contact with solids – Processes – Including application of electrical radiant or wave energy...
Reexamination Certificate
1999-10-15
2002-03-26
Markoff, Alexander (Department: 1746)
Cleaning and liquid contact with solids
Processes
Including application of electrical radiant or wave energy...
C134S006000, C134S009000, C134S042000, C425S229000, C425S4360RM, C426S502000
Reexamination Certificate
active
06361609
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to an apparatus for sheeting dough products and, in particular, to a series of ultrasonic horns or blades used to strip a sheeter roller. The use of ultrasonic horns eliminates the need for a stripper wire and allows for the production of full-width dough sheets.
2. Description of Related Art
A sheeter is a device commonly used in the food industry for making flattened food products, such as tortilla chips, in a continuous processing operation. Typically, a dough product is compressed between a pair of counter rotating sheeter rollers that are located closely together, thereby providing a pinch point through which the dough is formed into sheets. The dough can then be cut by, for example, a cutting roller to form the shape of the product desired.
Many dough products, particularly those that are corn based (“masa”), have a tendency to stick to the sheeter rollers rather than dropping onto a conveyer for transportation to the next processing step, such as a baking oven. This is because masa is relatively sticky and has very little cohesive strength. The masa will not support its weight as it falls from the sheeter and cannot be pulled off the sheeter. The use of a stationary scraper blade, as is commonly used with flour dough applications, is not practical because the masa tends to build on and stick to the scraper blade. One common approach to this problem is to string a stripper wire across the face of the sheeter roller so that the stripper wire can scrap away the dough product off of the surface of the roller.
An example of a prior art sheeter wire design in this regard is illustrated by
FIGS. 1
and
2
.
FIG. 1
is a perspective view of the output of a dough sheeter device
110
. The cut dough product, in this case uncooked tortilla chips
120
made from masa, can be seen on a conveyer
130
after being deposited on the conveyer
130
by a sheeter roller
140
. The sheeter roller
140
will typically have a plurality of plastic bands
150
about the circumference of the sheeter roller
140
. These bands
150
ride in groves (now shown) in the sheeter roller
140
and hold the sheeter wire
160
close to the surface of the sheeter roller
140
. The bands
150
also provide a surface for returning ribbons of unused masa to the sheeter
110
.
A sheeter wire
160
is shown strung across the face of the sheeter roller
140
. This sheeter wire
160
is attached to two fixed points
170
,
180
and is threaded across the face of the sheeter roller
140
underneath each of the bands
150
. This provides a flush contact between the sheeter wire
160
and the surface of the sheeter roller
140
. The second fixed point
180
could also comprise a tension device such as a hydraulic or pneumatic device that provides a constant tension on the wire
160
. Such a tension device is typically connected to a warning device to provide an indication of wire breakage.
FIG. 2
is a schematic side view of a prior art sheeter wire design installed on a sheeter device. Masa
205
is fed between a press roller
207
and the sheeter roller
240
. The press roller
207
turns at a slower rotational speed than the sheeter roller
240
. This results in the masa
205
adhering to the sheeter roller
240
. The masa
205
is next cut by a cutter roller
209
. The cut masa is then stripped from the sheeter roller
240
, by the sheeter wire
260
. The cut product
220
then drops onto a conveyor
230
to be transported for further processing. As will be described below, sheeters using a sheeter wire arrangement such as illustrated in
FIGS. 1 and 2
have three primary drawbacks—wire
160
breakage, band
150
breakage, and an inability to produce full-width sheets.
Returning to
FIG. 1
, the sheeter wire
160
is typically commercial piano wire. A typical tension on the wire during operation is 100 to 125 pounds. Contact with hardened masa, particularly during start-up, can subject the sheeter wire
160
to higher tension for short time periods. During operation the wire
160
is also subject to friction from the moving face of the sheeter roller
140
. This wire
160
must be replaced periodically or the wire
160
is prone to breakage after time. In fact, in a continuous use operation for a typical sheeter device producing tortilla chips, it has been observed that such fixed sheeter wire
160
will break, if not replaced, nearly daily.
In order to replace a broken sheeter wire the entire sheeter device
110
and, consequently, the entire chip processing assembly, must be stopped. The broken sheeter wire
160
is removed. A new sheeter wire
160
is attached to the first attaching point
170
, strung across the face of the sheeter roller
140
under the bands
150
, and attached to a second attaching point
180
. Then the tension device
190
must be reactivated. Raw material is lost because the dough that was on the sheeter must be thrown away and additional product downstream may need to be discarded. Start-up procedures must next be followed, which result in further lost product. A wire breakage event, therefore, results in a substantial amount of unscheduled downtime and lost product. The alternative is to schedule, on a daily basis, the replacement of the sheeter wire
160
. A scheduled replacement of the sheeter wire
160
, however, results in even more frequent, although scheduled, downtime.
One attempt at addressing the wire breakage problem is reflected in U.S. Pat. No. 5,720,990 (“Lawrence”) issued on Feb. 24, 1998. The Lawrence patent discloses a wire separator system for a sheeter device comprising a motor that drives a feed spool and a motor that drives a take-up spool. Tension is maintained on the sheeter wire by use of a tension sensing pulley providing input to a controller which modulates the torque on the take-up reel. Provided that the wire does not unexpectedly break, the Lawrence patent discloses a device that will allow the sheeter to run for long periods of time without the necessity of stopping the sheeter to replace the sheeter wire, because new wire is constantly drawn across the contact surface.
The invention disclosed by Lawrence has several drawbacks, however. First, the design assumes that the wire will not break during operation. Unfortunately, this is not a safe assumption. In fact, it is not an infrequent occurrence that wire breakage occurs on the prior art model illustrated by
FIG. 1
shortly after a new wire has been installed. This could occur due to a sudden contact with a dried piece of dough that has become affixed to the sheeter while the sheeter is stationary. Further, an initial steady-state friction between the sheeter wire and the sheeter must be overcome at the instant the sheeter begins to rotate. Since the Lawrence device provides that one motor feeds wire while another motor takes-up wire, a breakage between the two motors can result in the continued feeding of wire into the sheeter until the feed motor comes to a stop. A breakage also results in a loss of tension on the feed spool and can lead to unraveling or the “weed eater” effect, whereby the spool becomes unwound. Further, the Lawrence device is designed to maintain constant tension of the wire by using a variable speed pulling motor connected to the take-up reel. Since the Lawrence feed spool is connected to a fixed speed motor, the tension will necessarily fluctuate at the point that the wire is leaving the feed spool when, for example, the wire encounters a piece of dried dough product on the sheeter during operation. These torque fluctuations could effect the consistency of the feed spool's wound tension, thereby leading to further torque fluctuations and potential feed problems.
Minor breakage issues aside, the prior art sheeter device illustrated in FIG.
1
and the Lawrence device have other shortcomings and problems. For example, the bands
150
that hold the sheeter wire
160
in place are also subject to frequent breakage. Band breakage will probably occur with even greater frequency when a continuously drawn
Leon Ouellette Edward
Perdue Samara Renee
Wilson Barry Forster
Cahoon Colin P.
Carstens, Yee & Cahoon
Markoff Alexander
Recot Inc.
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