Patent Publication Number: US-2011076373-A1

Title: Popcorn machines and other machines having reversible food moving devices for popping popcorn and producing other types of expanded foods

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) INCORPORATED BY REFERENCE 
     The present application claims priority to and the benefit of U.S. Provisional Application No. 61/247,394, filed Sep. 30, 2009, and entitled “POPCORN MACHINES AND OTHER MACHINES HAVING REVERSIBLE FOOD MOVING DEVICES FOR POPPING POPCORN AND PRODUCING OTHER TYPES OF EXPENDED FOOD,” which is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The following disclosure relates generally to systems and methods for popping corn and producing other types of expanded foods. 
     BACKGROUND 
     Popcorn machines for use in theaters, concession stands, and homes are well known. Industrial machines for making large quantities of popcorn, puffed rice, and other expanded food products for wholesale to retailers are also known. Conventional popcorn machines typically include a popping kettle positioned inside a cabinet. To make popcorn, unpopped corn kernels are placed in the kettle with cooking oil and heated with a gas burner or electric heating element. The cooking oil coats the kernels and ensures a relatively even distribution of heat throughout the kernel. 
     Agitating the kernels can prevent them from burning on the bottom of the kettle where the heat is most intense. For this reason, many popcorn machines include some type of agitator that mixes the corn kernels with the cooking oil and ensures even popping. Some machines, for example, include stirring blades that are mounted to a rotating shaft driven by an electric motor. In operation, the stirring blades sweep around the inside of the popping kettle, mixing the kernels with the cooking oil and ensuring the kernels are evenly heated. 
     In conventional popcorn machines, the temperature of the popping surface is thermostatically controlled to a uniform temperature of about 480° F. When the corn kernels and oil are poured onto the hot surface, the temperature of the surface initially drops to about 380° F. Over the next three to four minutes, the temperature rises back to approximately 480° F. and the kernels begins to pop. Most conventional kettles have a lid that allows the popped corn to spill out of the kettle as the volume of popped corn increases. When the popping operation is complete, the kettle can be tilted to dump any remaining popcorn onto the floor of the cabinet, and the cycle can be repeated. After popping, butter, oil, caramel, and/or other flavorings can be added to the popcorn if desired. 
     Corn kernels are pressure vessels that consist of about 14% moisture. When heated, the starch in the kernel becomes gelatinized (i.e., a thick liquid) and the moisture turns to steam which raises the internal pressure. When the internal pressure reaches about 135 pounds per square inch (PSI), the kernel explodes. As the kernel explodes, the steam expands and stretches the starch cells as the pressure drops to atmospheric. The temperature drops with the dropping pressure, and the starch freezes into a foam structure having a volume that is about 50 times greater than the original kernel. 
     Although heat is applied to the outside of the kernel during the popping process, the kernel is preferably cooked to the core for satisfactory popping. If the kernel is heated too rapidly, the kernel will pop before it is cooked to the core and the center will be hard and less satisfactory for eating. Conversely, if the kernel is heated too slowly, all the moisture may leak out before it reaches popping pressure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partially schematic isometric view of a popcorn machine having a reversible food moving device configured in accordance with an embodiment of the disclosure. 
         FIG. 2  is an enlarged end view of a cooking assembly from the popcorn machine of  FIG. 1 . 
         FIGS. 3A and 3B  are side cross-sectional views of the popcorn machine of  FIG. 1 . 
         FIG. 4  is a schematic diagram of a flow routine illustrating a method for operating a food moving device in a popcorn machine in accordance with an embodiment of the disclosure. 
         FIG. 5  is a schematic diagram of a flow routine illustrating a method for operating a food moving device in a popcorn machine in accordance with another embodiment of the disclosure. 
         FIG. 6  is a partially schematic isometric view of a popcorn machine having a reversible food moving device configured in accordance with another embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The following disclosure describes various embodiments of popcorn machines and other machines for producing expanded food that have reversible drive systems (e.g., an auger) that can move food in two directions (e.g., forward and back) on a cooking surface. In one embodiment, for example, a popcorn machine has a reversible auger with a spiral blade that moves raw popcorn kernels (or other food product) along a heated, trough-shaped cooking surface by repeatedly moving the corn forward a first amount and then back a second, lesser amount. More specifically, in this embodiment the auger rotates in a first direction to move the corn kernels forward a first distance, and then in the reverse direction to move the corn kernels back a second distance that is less than the first distance. These phases of auger rotation continue in a repeating cycle; and because the auger rotates further in the first direction in each cycle than in the second direction, the net result is that the auger ultimately moves the corn over the entire length of the cooking surface. The back and forth movement of the popcorn kernels provides good agitation of the corn and keeps it immersed in the cooking oil for even heating. In contrast, rotation of the auger in a single direction tends to push the corn up the sidewall of the trough-shaped cooking surface and away from the oil. 
     Certain details are set forth in the following description and in  FIGS. 1-6  to provide a thorough understanding of various embodiments of the invention. Other details describing well-known structures and systems often associated with popcorn machines, rice puffing machines, snack puffing machines, etc. have not been set forth in the following disclosure to avoid unnecessarily obscuring the description of the various embodiments of the invention. 
     Many of the details, dimensions, angles and other features shown in the Figures are merely illustrative of particular embodiments of the disclosure. Accordingly, other embodiments can have other details, dimensions, angles and features without departing from the spirit or scope of the present invention. In addition, those of ordinary skill in the art will appreciate that further embodiments of the invention can be practiced without several of the details described below. 
     In the Figures, identical reference numbers identify identical, or at least generally similar, elements. To facilitate the discussion of any particular element, the most significant digit or digits of any reference number refer to the Figure in which that element is first introduced. For example, element  110  is first introduced and discussed with reference to  FIG. 1 . 
       FIG. 1  is a partially schematic isometric view of a food expanding machine  100  configured in accordance with an embodiment of the disclosure. In the illustrated embodiment, the food expanding machine  100  is a popcorn machine for popping raw corn kernels in, e.g., a large scale industrial setting. (Accordingly, for ease of reference the food expanding machine  100  will be referred to hereinafter as a popcorn machine  100 ). In other embodiments, however, the machine  100  and suitable variations thereof can be used for making other types of expanded food products such as puffed rice, puffed snacks (e.g., extruded starch snacks) and other types of expanded foods. Accordingly, while portions of the present disclosure may be directed to popcorn machines, it should be understood that various embodiments of the machines and methods described herein can be used to produce other types of expanded food products. 
     In the illustrated embodiment, the popcorn machine  100  includes a cooking assembly  110  having a heated cooking surface  112 . The cooking surface  112  can include a metallic surface having a generally semi-circular cross-sectional shape in the form of a trough. In other embodiments, the cooking surface can have other shapes. The cooking surface  112  can be formed from stainless steel and/or other suitable metals known in the art. In some embodiments, the popcorn machine  100  and features thereof can be at least generally similar in structure and function to the popcorn machines described in U.S. patent application Ser. No. 11/942,648, filed Nov. 19, 2007, and entitled “POPCORN MACHINES AND OTHER MACHINES HAVING MULTIPLE HEAT ZONE COOKING SURFACES FOR PRODUCING POPCORN AND OTHER TYPES OF EXPANDED FOODS,” which is incorporated herein in its entirety by reference. 
     In the illustrated embodiment, a plurality of first heating elements  142  and second heating elements  144  are positioned proximate the underside of the cooking surface  112  to heat the cooking surface and pop, puff and/or expand food product placed thereon. Each of the heating elements  142 ,  144  can include a resistive wire (not shown) or other element encased in a metallic casing. Each of the resistive wires can receive electric power from a controller  140  that in turn receives electric power from a facility outlet via a power cord  146  to generate heat as known in the art. In other embodiments, other suitable heating elements (e.g., gas burners) known in the art in other arrangements can be used to heat the cooking surface  112 . 
     A food moving device or auger  116  is operably positioned adjacent to the cooking surface  112 . In one embodiment, the auger  116  has a helical or spiral blade with an outer diameter that is about the same, or slightly smaller, than the inner diameter of the semi-circular lower portion of the cooking surface  112 . The auger  116  includes a central shaft  114  rotatably coupled to an electric motor  120  by means of a drive belt  122 . The electric motor  120  is operably connected to the controller  140  and configured to rotate the auger  116  in two directions (e.g., clockwise and counterclockwise) about a longitudinal axis  118 . In other embodiments, the auger  116  can be driven by a gear system, a direct drive system, etc. 
     In another aspect of this embodiment, the popcorn machine  100  includes a raw corn hopper/dispenser  152  and a cooking oil container/dispenser  154 . The corn hopper  152  includes a corn feed outlet  156  that dispenses unpopped corn kernels  172  onto a first end portion of the cooking surface  112 . Similarly, the cooking oil container  154  includes an oil feed outlet  158  that dispenses cooking oil  176  onto the cooking surface  112  to mix with the incoming corn kernels  172 . 
     In the illustrated embodiment, an operator control panel  148  (shown schematically) having a keypad, one or more push-buttons or switches, and/or other user interface devices  184  is operably coupled to the controller  140 . The controller  140  can include a processor  180  for executing computer-readable operating instructions stored on memory  182 . The processor  180  can include a programmable logic controller (PLC) and/or other processing device suitable for executing computer-readable instructions for controlling operation of the popcorn machine  100  in accordance with operator input received via the control panel  148 . For example, in one embodiment the operator may turn the popcorn machine  100  on/off, set popping time, set popping temperature, etc. via the control panel  148 . 
     The controller  140  provides electric power to the heating elements  142 ,  144  and the electric motor  120  in response to operator inputs via the control panel  148 . The electric power causes the motor  120  to rotate the auger  116  as the popcorn kernels  172  and cooking oil  176  are dispensed onto the cooking surface  112 . For example, in one embodiment the auger  116  rotates in a first direction R 1  (e.g., the forward direction) through a first phase or first angle of rotation (e.g., 360 degrees), and then reverses direction and rotates backward in a second direction R 2  through a second phase or second angle of rotation (e.g., 300 degrees). This cycle continuously repeats as the popcorn and cooking oil mixture makes its way down the length of the heated cooking surface  112 . Because the auger  116  rotates more in the first (forward) direction R 1  and than in the second direction R 2 , the auger  116  ultimately drives the corn  172  over the entire length of the cooking surface  112 . The back and forth motion of the auger  116  provides good agitation of the raw corn  172  and helps to keep the corn in the cooking oil  176 . As it approaches the end portion of the cooking surface  112 , the heated corn  172  begins to pop and become popcorn  174 . The auger  116  drives the popcorn  174  out of the cooking assembly  110  and into a receptacle  130 . 
     In a further aspect of this embodiment, the first heating elements  142  and the second heating elements  144  can provide two different heat zones on the cooking surface  112 . For example, in some embodiments the first heating elements  142  can be heated to a first temperature ranging from about 350° F. to about 430° F., e.g., about 380° F., and the second heating elements  144  can be heated to a second temperature ranging from about 450° F. to about 500° F., e.g., about 480° F. In other embodiments, other operating temperatures can be selected for the first and second heating elements  142 ,  144  depending on the particular configuration of the cooking surface and/or other factors. In one embodiment, the first heating elements  142  can heat the corn kernels  172  on the first portion of the cooking surface  112  to a first temperature range of from about 72 degrees F. to about 380 degrees F., and the second heating elements  144  can heat the corn on the second portion of the cooking surface  112  to a second temperature range of from about 380 degrees F. to about 500 degrees F. As explained in U.S. patent application Ser. No. 11/942,684, operating a first heat zone at a first temperature and the second heat zone at a second, higher temperature provides gradual heating of the corn kernels  172  and prevents them from cooking too fast or too slow, resulting in a fully expanded popped corn without hard centers. In other embodiments, however, the cooking surface  112  can have one, two, or more heat zones heated to other temperatures in other ways. For example, in one embodiment the first heat zone can be operated at a higher temperature than the second, downstream heat zone. In other embodiments, the cooking surface  112  can have three or more heat zones. In further embodiments, the cooking surface  112  can be heated to a uniform or at least generally uniform temperature using only one heating element or one group of heating elements. Accordingly, the various popcorn machines and expanded food machines disclosed herein are not limited to a particular type of heated surface or heating device. 
       FIG. 2  is a partially schematic, enlarged end view of the cooking assembly  110  configured in accordance with an embodiment of the disclosure. As this view illustrates, the first heating elements  142  and second heating elements  144  can be aligned with each other, or at least approximately aligned with each other beneath the cooking surface  112 . Moreover, the first heating elements  142  can include five individual heating elements (identified individually as first heating elements  142   a - e ) and the second heating elements  144  can include five individual heating elements (identified individually as second heating elements  144   a - e ). The heating elements  142 ,  144  can be radially spaced apart from each other around the semi-circular bottom portion of the trough-shaped cooking surface  112 . In addition, one or more temperature sensors  250  (e.g., thermocouples, thermostats, etc.) can be operably coupled to the cooking surface  112  and to the controller  140  ( FIG. 1 ) to actively monitor the temperature of the cooking surface  112 . The controller  140  can utilize the information from the one or more temperature sensors  250  to control the power to the heating elements  142  and  144  to thereby control the temperature of the cooking surface  112 . 
       FIGS. 3A and 3B  are partially schematic cross-sectional side views of the popcorn machine  100  configured in accordance with an embodiment of the disclosure. Referring first to  FIG. 3A , a plurality of the temperature sensors  250  (identified individually as temperature sensors  250   a - d ) can be operably coupled to the underside (or proximate the underside) of the cooking surface  112  to provide temperature information to the controller  140 . As described above, the controller  140  can control electric power to the first heating elements  142  and the second heating elements  144  based on the temperature information received from the temperature sensors  250 . For example, the controller  140  can distribute electric power to the first heating elements  142  and the second heating elements  144  to provide a first heat zone  351  on a first portion of the cooking surface  112  and a second, higher temperature heat zone  352  downstream of the first heat zone  351 . In one embodiment, the first heat zone  351  can have a first surface temperature ranging from about 350° F. to about 430° F., e.g., about 380° F. The second heat zone  352  can have a second surface temperature ranging from about 450° F. to about 500° F., e.g., about 480° F. Providing stepped or increasingly hotter heat zones on the cooking surface  112  gradually heats the raw popcorn  172  and provides favorable popping characteristics. 
     As explained above, in one embodiment the auger  116  can rotate in the first or forward direction R 1  for about 360 degrees, then rotate in the reverse direction R 2  for about 300 degrees, and then repeat the cycle.  FIG. 3A  illustrates how the auger  116  moves the raw popcorn  172  forward when the auger  116  rotates in the first direction R 1 .  FIG. 3B  illustrates how the auger  116  moves the raw popcorn  172  backward when the auger  116  rotates in the second direction R 2 . 
       FIG. 4  is a schematic diagram of a flow routine  400  for operating a popcorn machine having a reversible food moving device in accordance with an embodiment of the disclosure. In one embodiment, the routine  400  or portions thereof can be performed by the processor  180  in the controller  140  of the popcorn machine  100  in accordance with computer-readable instructions stored in the memory  182  ( FIG. 1 ). In other embodiments, the routine  400  can be utilized by other popcorn machines and other machines for producing expanded food products. 
     After the operator has turned the popcorn machine (e.g., the popcorn machine  100 ) “on” and provided the necessary operating inputs, the routine begins in block  402  by initializing or setting the angle of auger rotation to zero degrees. In block  404 , the auger begins to rotate in a first direction (e.g., the forward direction or the direction that drives the food product forward on the cooking surface). In decision block  406 , the routine determines if the auger has rotated through an angle of A 1  degrees. For example, in one embodiment the angle A 1  can be from about 340 degrees to about 380 degrees, or about 360 degrees. If the auger is not rotated through an angle of 360 degrees, the routine returns to block  404  and continues to rotate the auger in the first direction. Once the auger has rotated in the first direction through an angle A 1  of 360 degrees, the routine proceeds to block  408  and resets the measurement of auger angle back to zero. 
     In block  410 , the routine begins rotating the auger in the second direction to move food product (e.g., corn kernels) backward on the cooking surface. In decision block  412 , the routine determines if the auger has turned through an angle of A 2  degrees in the second direction. For example, in one embodiment the angle A 2  can be from about 260 degrees to about 340 degrees, or about 300 degrees. If the auger has not rotated through an angle of 300 degrees in the second direction, the routine returns to block  410  and continues to rotate the auger in the second direction. Once the auger has rotated through an angle of 300 degrees in the second direction, the routine proceeds to decision block  414  to determine if the selected cooking cycle for the particular quantity and/or type of food product is complete. For example, in one embodiment the routine can determine if there is any more corn on the cooking surface to pop. If the cooking cycle is not complete, the routine returns to block  402  and repeats the cycle of running the auger in the first direction and then in the reverse direction. When the cooking cycle is complete (e.g., when all the food product has been popped or otherwise expanded, when the operator turns the popcorn machine “off,” etc.) the routine ends. 
       FIG. 5  is a schematic diagram of a flow routine  500  that is at least generally similar to the flow routine  400  described above. In this embodiment, however, rather than measure the phase or the amount of auger rotation in a particular direction, the routine measures the amount of time that the auger has rotated in a particular direction. For example, after the operator has turned the popcorn machine “on” and set the desired cooking parameters, the routine proceeds to block  502  and initializes the time of auger rotation to zero. In block  504 , the routine begins rotating the auger in the first direction (e.g., forward). In decision block  506 , the routine determines if the auger has rotated in the first direction for a time period equal to T 1 . In one embodiment, for example, the elapsed time T 1  can be about the amount of time it takes for the auger to rotate through 360 degrees, which will vary depending on the rotational speed of the auger. In other embodiments, however, the time period T 1  can be set to other periods of time. 
     If the auger has not rotated in the first direction for the predetermined amount of time, then the routine returns to block  504  and continues to rotate the auger in the first direction. Once the auger has rotated in the first direction for the time period T 1 , the routine proceeds to block  508  and resets the elapsed time to zero. In block  510 , the auger is then run in the second direction (e.g., reverse). In block  512 , the routine determines if the auger has rotated in the second or reverse direction for a predetermined second period of time T 2 . In one embodiment, for example, the elapsed time T 2  can be about the amount of time it takes for the auger to rotate through 300 degrees. If the auger has not rotated in the second direction for the period of time T 2 , the routine returns to block  510  and continues to rotate the auger in the second direction. Once the auger has rotated in the second direction for the second period of time T 2 , the routine proceeds to decision block  514  to determine if the cooking cycle is complete. If not, the routine returns to block  502  and repeats the cycle of alternating auger rotation as described above. Once the cooking cycle is complete, the routine  500  ends. 
     Although the foregoing embodiments describe alternating periods of auger rotation corresponding to 360 degrees of rotation in the forward direction and 300 degrees of rotation in the reverse direction, in other embodiments the auger or other food moving device can rotate or otherwise move back and forth for other time periods and/or other distances. For example, in other embodiments the auger can rotate forward for 270 degrees and backward for 180 degrees. Accordingly, the present disclosure is not limited to the particular phases, angles, and/or time periods described above, and contemplates a wide variety of operational parameters. 
     Although the foregoing description of reversible food moving devices have been described above in the context of a linear popcorn machine having a trough-shaped cooking surface, the various aspects and features of the reversible food moving devices described above can also be employed in other types of popcorn machines and food expanders in accordance with the present disclosure.  FIG. 6 , for example, is a partially schematic isometric view of a portion of a popcorn machine  600  having a kettle assembly  610  configured in accordance with another embodiment of the disclosure. By way of example, the kettle assembly  610  can be at least generally similar in structure and function to the kettle assemblies and related devices disclosed in international PCT Patent Application No. PCT/EP2005/009010 (Publication No. WO 2006/021387 A1), filed Aug. 19, 2005 (claiming priority to DE Patent Application No. 10 2004040662.6, filed Aug. 20, 2004), entitled “METHOD AND DEVICE FOR THE PRODUCTION OF EXPANDED FOOD,” which is incorporated herein in its entirety by reference. 
     In the illustrated embodiment, the kettle assembly  610  includes a heating vessel or pan  611  having a popping surface  612  positioned above heating elements  642   a,b . A food moving device  613  is operably positioned inside the pan  611 . In the illustrated embodiment, the food moving device  613  includes a plurality of rod-like stirring blades or rakes  616  (identified individually as rakes  616   a - i ) which extend outwardly from a central hub  614  in a radial pattern. In other embodiments, however, the rakes  616  can include paddle-like surfaces that extend upwardly from the popping surface  612 . These surfaces and/or rakes can help push the popcorn out of the kettle assembly  610  after popping. The rakes  616  rotate about a central axis  680  by means of a drive shaft  618  which is operably coupled to the hub  614 . The drive shaft  618  is in turn driven by an electric motor  660 . 
     In operation, the electric motor  660  rotates the rakes  616  about the central axis  680  in a first direction D 1  as corn kernels and cooking oil (not shown) are fed onto the popping surface  612 . As the rakes  616  rotate, they move the unpopped corn kernels outwardly on the popping surface  612  away from the hub  614 . In one aspect of this embodiment, after rotating the rakes  616  in the first direction D 1  a first predetermined amount, the electric motor  660  can reverse direction of the shaft  618  and rotate the rakes  616  in a second direction D 2  for a second predetermined period of time. As described above with regard to the linear popcorn machine  100 , reversing direction of the rakes  216  can keep the unpopped corn kernels suitably mixed with the cooking oil and provide other desirable popping characteristics. 
     From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the various embodiments of the invention. Further, while various advantages associated with certain embodiments of the invention have been described above in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the invention. Accordingly, the invention is not limited, except as by the appended claims.