Abstract:
A dough forming apparatus for flatbread products, the apparatus having: a loading station; a pressing station; a discharge station; and a conveyor belt passing through the loading station, the pressing station and the discharge station; wherein the discharge station further comprises a heated discharge platen.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a dough processing apparatus, such as a flour tortilla making machine, and in particular is directed to an improved discharge platen for such an apparatus. 
     Normally, presses for flat breads and tortillas have upper and lower platens equipped with heat elements. Dough balls are moved on a conveyor through the press. After the dough balls are pressed flat, the resulting flattened dough elements are typically moved onto an unheated holding station to rest for a second or two before being discharged into an oven or for other subsequent processing. 
     Discharge typically involves some combination of malleable or flexible-stripping elements mounted to a rotating shaft, as well as a jet of air to aid in the transfer of the pressed dough elements from the holding station onto a mesh or other conveyor. The discharge is often a source of great waste. If the bottom side of a pressed dough element is not heated enough, then the pressed dough element will not release from the main conveyor without distortion to the product. Conversely, if the bottom side of a pressed dough element is heated too much, then the pressed dough element can be dislodged from its relative orientation causing waste from overlaps. 
     Therefore, problems discharging pressed dough elements from the holding station often limit production speed and negatively impact the quality of the finished products. There is a need for an improved apparatus for processing pressed dough. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is direct to a dough forming apparatus for flatbread products, the apparatus comprising: a loading station; a pressing station; a discharge station; and a conveyor belt passing through the loading station, the pressing station and the discharge station; wherein the discharge station further comprises a heated discharge platen. 
     The heated discharge platen can have a variable heating element. Additionally, the discharge platen can have a temperature sensor. A controller can be coupled to the variable heating element and the temperature sensor, the controller altering the heat from the heating element in response to a temperature sensed by the temperature sensor. 
     The heat discharge platen can be heated by an open flame positioned below the heated discharge platen. Alternatively, the heated discharge platen has a channel with an electric heating element positioned in the channel or a heated fluid pumped through the channel. Additionally, the pressing station may have heated upper and lower pressing platens with the upper pressing platen being heated to a higher temperature than the lower pressing platen. 
     The present invention is also directed to a method for making dough for flatbread products comprising the steps of: loading a dough ball on a conveyor at a loading station; advancing a dough ball on the conveyor to a pressing station; pressing the dough ball in the pressing station; forwarding the pressed dough ball to a discharge station; and heating the pressed dough ball on the discharge station. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description, appended claims, and accompanying drawings, where: 
         FIG. 1  is a side elevation view of a dough processing apparatus according to an embodiment of the present invention; 
         FIG. 2  is a perspective view of the apparatus of  FIG. 1  showing a partially cut-away discharge platen; 
         FIG. 3  is a magnified view of portion  3  of  FIG. 2 ; and 
         FIG. 4  is a schematic diagram of a system employing a heated discharge platen according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 and 2 , a dough pressing apparatus, generally designated  10 , of the type in which the heated discharge platen of the present invention may be used is illustrated. The apparatus  10  includes a support housing  11  that supports the apparatus  10  on the ground and contains many of the operating components and controls (not shown) for the apparatus. The apparatus includes a loading station  12 , a pressing station  14  and a discharge station  16  for loading, pressing and discharging, respectively, the dough balls that are being processed by the apparatus  10 . 
     Dough balls are placed onto a conveyor belt  18 . The apparatus may be of a width to accommodate plural rows of dough balls. The conveyor belt  18  is then advanced a predetermined distance by a drive roller  20  which is rotated by a drive mechanism  22  for a predetermined number of revolutions to cause the desired distance of movement of the conveyor belt to bring the dough balls into proper position within the pressing station  14 . 
     When the conveyor belt  18  is stopped by stoppage of the drive roller  20 , an upper pressing platen  24  of the pressing station  14  is moved downwardly with an appropriate force and spacing from a lower pressing platen  26  of the pressing station  14  for squeezing the dough balls to a desired thickness and shape. One or both of the pressing platens  24  and  26  are heated for causing parbaking of the dough balls to maintain a flattened condition and proper texture. The upper pressing platen  26  is then raised and the conveyor belt is advanced by the drive roller  20  to move the flattened dough balls from the pressing station  14  to the discharge station  16  and advance new dough balls from the loading station  12  to the pressing station  14  for repeating the cycle. 
     The discharge station  16  has a heated discharge platen  28 . Preferably, the discharge platen  28  is made of metal such as aluminum. The discharge platen  28  is heated by a heater  30 . 
     In an embodiment of the present invention, as shown in  FIGS. 2 and 3 , the heater  30  is an electric heater. Channels  32  are formed throughout the platen, such as by drilling. Rod shaped electric heating elements  34  are mounted in the channels  32  using an adhesive. Such a construction is advantageous, because broken heating elements  34  can be removed from the channels and replaced. Additionally, individual heating elements can be separately and variably controlled. Alternatively, a circular or annular heater may be coupled to the discharge platen or routed inside a circular shaped channel formed in the discharge platen. 
     In an alternative embodiment, the heater  30  utilizes a recirculated fluid such as oil heated by a heat source. In this embodiment, a plurality of channels are formed in the discharge platen  28  and the heated fluid is pumped through the channels by a pump. The channels may have a variety of different shapes to distribute the heated fluid through the discharge platen so as to either heat the platen uniformly or to variably heat particular portions of the discharge platen. For example, the channels may be serpentine, or circular. This type of heater is advantageous because it allows for uniform heating of the discharge platen. In another alternative embodiment of the present invention, the heater  30  is an open flame positioned below the discharge platen  28 . 
     As shown in  FIG. 4 , at least one temperature sensor  36 , such as a thermocouple made by Allen Bradley of Rockwell Automation in Milwaukee, Wis. may be coupled to the discharge platen to monitor the temperature. For example, the temperature sensor  36  may be mounted in the center of the discharge platen  28 . A plurality of temperature sensors may be coupled to the discharge platen to monitor the temperature at a plurality of different locations. 
     Preferably, the temperature sensor  36  and the heater  30  are coupled to a controller  38 . The controller  38 , which may be a computer coupled to user input and display devices, may be independent. Alternatively, the controller  38  may also control one or more of the heating of the upper pressing platen  24 , the heating of the lower pressing platen  26  and the speed of the conveyor. The use of a plurality of thermocouples in combination with a heater having a plurality of separately controllable heating elements allows for differential temperatures to be separately generated and controlled on different areas of the discharge platen. 
     Optionally, the discharge platen is multilayered. Separately controllable heaters  30  and thermocouples  36  may be provided for each layer. 
     As a result of the heated discharge platen of the present invention, faster dough processing apparatus cycling times can be achieved. Additionally, products produced by a dough processing apparatus according to the present invention have greater consistency. Additionally, the temperature of the lower pressing platen can be lowered, because the discharge platen allows for additional heating of the lower side of the pressed dough element. Lowering the temperature of the lower pressing platen allows for the formation of rounder product shapes. 
     All features disclosed in the specification, including the claims, abstract, and drawings, and all the steps in any method or process disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. Each feature disclosed in the specification, including the claims, abstract, and drawings, can be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. 
     Also, any element in a claim that does not explicitly state “means for” performing a specified function or “step for” performing a specified function, should not be interpreted as a “means” or “step” clause as specified in 35 U.S.C. section 112. 
     Although the present invention has been discussed in considerable detail with reference to certain preferred embodiments, other embodiments are possible. Therefore, the scope of the appended claims should not be limited to the description of preferred embodiments contained in this disclosure.