Abstract:
A system ( 50 ) is provided for the production of elongated comestible products such as hot dogs, without the use of traditional casings. The system ( 50 ) includes a circular pattern of arrays ( 92 ) of elongated, open-ended, extruded synthetic resin cooking tubes ( 92, 94 ) within a rotatable cylindrical heating drum or housing ( 70 ). The tube housing ( 70 ) and arrays ( 92 ) are incrementally rotated and at each stop position certain of the tubes ( 92, 94 ) are filled with portions of meat emulsion ( 590 ) and alternating plugs ( 208 ), while previously filled tubes ( 92, 94 ) containing cooked product are unloaded, and other unfilled tubes are internally coated with a lubricant (e.g., a mixture of lecithin and vegetable oil). Energy exchange media such as hot water and/or steam are used within the housing to continuously cook the emulsion portions within the tubes ( 92, 94 ) to the desired extent.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of application Ser. No. 12/703,396, filed Feb. 10, 2010, and further claims the benefit of Provisional Application Ser. No. 61/222,765, filed Jul. 2, 2009, and of Provisional Application Ser. No. 61/152,576, filed Feb. 13, 2009. All of the above-identified applications are incorporated by reference herein in their entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention is concerned with improved apparatus and methods for the commercial-scale production of elongated cooked food items such as hot dogs, corn dogs and sausages (e.g., Vienna sausages) without the use of casings. More particularly, the invention is directed to such devices and methods wherein automated injector heads coupled with a supply of meat emulsion create successive, predetermined weight portions or charges of emulsion which are then partially or completely cooked in elongated heat exchange cooking tubes. The equipment is preferably designed so that the products are statically heated using a plurality of tubes so as to achieve a batch-continuous operation. Advantageously, the equipment provides a plurality of cooking tube arrays, and delivers meat emulsion to at least one tube array while also removing cooked product from a second array and applying oil to a third array. 
         [0004]    2. Description of the Prior Art 
         [0005]    Presently, elongated cooked meat products such as hotdogs, the inner meat portions of corn dogs, and Vienna sausages are produced using casings. Generally speaking, a starting meat emulsion is pumped into a casing, and the casing is twisted in order to initially form the product, followed by cooking and/or smoking to fully cook and gelatinize the protein in the emulsion. The product is chilled and the casing is stripped from the cooked product and is discarded. Such use of casing represents a very significant cost to the food processors. Indeed, many large scale plants purchase several million dollars worth of casings per year. 
         [0006]    Attempts have been made in the past to process these meat products without the use of casings. However, these efforts have not met with any significant commercial acceptance. The principal difficulty with these prior devices has been that the products are not equivalent to the typical products made with casings. For example, the products may not have the same shape, color, or texture as the conventional counterparts, and are thus unacceptable to consumers. 
         [0007]    U.S. Pat. No. 4,113,890 to Long describes a continuous stuffing machine  30  that feeds a tube  32  which injects emulsion into a coil  10  that is covered by a jacket  12 . A heat transfer medium, such as steam or hot water, flows through the jacket in a direction opposite to the flow of the emulsion through the coil  10 . Metal-core plugs  36  are also inserted into the coil  10  automatically by a loader  62 . The loader  62  has two similar chambers  72 ,  74  that rotate about a central axis  70  that is connected to a gear  64 , which may be driven by an external motor. One chamber  74  accepts (by the use of a hydraulic ram  78 ) a plug  36  from a supply line  60 , while at nearly the same time, the other chamber  72  injects (by the use of a hydraulic ram  76 ) a plug  36  into a feed line  10   c . The chambers  72 ,  74  rotate and perform reciprocal tasks in repeated fashion. The plugs  36  and the partially-cooked hot dogs exit the coil  10  onto conveyor  52 , where the plugs  36  are separated by a magnetic roller  54  from the hot dogs which continue on conveyor  56 . The plugs  36  are dropped into a receptacle  58 . 
         [0008]    U.S. Pat. No. 3,502,018 discloses a system for fully cooking sausages without casings. The system includes a stuffer  14  that forces meat emulsion into a tube which extends through multiple stages  10 ,  11 ,  12  of heating. Cooked sausage exits the tube  16  and is carried on a belt  26  through a cooling chamber  13 . Cooled sausage exits the cooling chamber  13  and may be cut by blade  32  before being transported by conveyor  36 . 
         [0009]    U.S. Pat. No. 3,889,013 discloses a system for preparing frankfurters or sausages by creating a casing from the meat product itself. The system includes a supply tank  2  that supplies the meat product to a metering pump  6  which delivers pressurized meat product to a heating unit  8 . The meat product is heated in a cylindrical mold  20  to cook the outer surface of the meat product so that it forms a casing. The meat product is then cooled by the cooling unit  10 . 
         [0010]    See also U.S. Pat. Nos. 2,182,211; 3,421,434; 4,726,093; 4,989,505; 5,056,425; 5,118,519; 6,203,832; 6,322,832; and 6,326,039. 
         [0011]    Notwithstanding these efforts, no commercially successful has heretofore been devised which is capable of properly cooking sausage-type products without casings and while retaining the appearance, taste, and mouth feel of traditional products. 
         [0012]    There is accordingly a real and unsatisfied need in the art for improved methods and apparatus capable of producing elongated, partially or fully cooked meat products such as hotdogs or sausages without the use of casings, while still providing finished products equivalent in all respects to conventional products of these types made using casings. 
       SUMMARY OF THE INVENTION 
       [0013]    The present invention overcomes the problems outlined above and provides greatly improved methods and apparatus for the production of elongated comestible products, and especially sausage-type products such as hot dogs, without the need for disposable casings. Thus, the invention entirely eliminates the costly expedient of using disposable casings, which greatly minimizes production costs. Moreover, the invention is characterized by reduced energy consumption owing to the use of conduction cooking, reduced labor costs, and improved food safety. The system of the invention also discharges product in an organized fashion wherein the products are oriented end-to-end in straight lines, which facilitates downstream product management. 
         [0014]    Generally speaking, the apparatus of the invention includes a plurality of elongated, separate, individual cooking tubes, each presenting a longitudinal axis and an inlet end. A loading station is provided which includes structure operable to load comestible material (e.g., meat emulsion) into the inlets of the tubes. Shifting mechanism is also provided which is operable to shift the tubes in a first direction transverse to the longitudinal axes thereof and into the loading station for successive loading. The shifting movement may be of any suitable type, such as circular or reciprocal. The overall apparatus further has a cooking arrangement to at least partially cook the comestible material within the tubes, as well as a discharge station separate from the loading station and including discharge structure for discharge of the at least partially cooked material from the cooking tubes. To this end, the shifting mechanism is also operable to successively shift the tubes containing the at least partially cooked comestible material in a second direction also transverse to the longitudinal axes and into the discharge station. 
         [0015]    Preferably, the cooking tubes have open inlet and outlet ends and are arranged in a circular pattern with the tubes substantially parallel with each other and in circumferentially spaced apart relationship. In this embodiment, the tubes are incrementally moved in the same direction (i.e., either clockwise or counterclockwise) into and out of the loading and discharge stations during rotation of the tube pattern. Advantageously, and in order to increase production capacity, an array of radially spaced apart tubes are provided at each circumferentially spaced apart tube position, and the loading and discharge stations are appropriately equipped to simultaneously load and discharge plural tubes. The arrays may have tubes of different diameters, so that differentially sized products may be produced on the same machine. In such an arrangement, the tubes are located within a cylindrical, axially rotatable, water-tight housing, and energy exchange media (e.g., heated water and/or steam) surrounds the tubes for cooking of the comestible material within the tubes during tube rotation. 
         [0016]    In order to create properly formed hot dog and related products, the loading station includes structure for successively introducing forming plugs into the tubes between successive portions of the comestible material. Thus, at the loading station, each cooking tube is filled with individual portions of material with a plug on either end of and in engagement with the portion. In such operations, the discharge station is equipped with specialized apparatus for recovery of the plugs as they are discharged, in order to return the plugs to the loading station for reuse. A particularly useful feature is that the plug recovery apparatus maintains the plugs in a substantially parallel alignment with the longitudinal axes of the tubes throughout the recovery sequence. Thus, the tubes are handled in the most efficient manner and without the need for manual manipulation thereof. 
         [0017]    The loading station of the system of the invention preferably includes an improved apparatus for loading of the cooking tubes with both portions of comestible material and forming plugs. This apparatus broadly includes a magazine operable to hold a plurality of the elongated plugs and to individually deliver the plugs to a plug delivery location. An elongated, axially shiftable plug seating rod is adjacent the magazine and is oriented to engage and move successive plugs from the plug delivery location. An elongated, axially rotatable plug and meat injection rod is provided, which is spaced from the seating rod and is located proximal to the tube inlet end, with the longitudinal axis of the injection rod being substantially coaxial with the tube longitudinal axis. The apparatus also has a portioning assembly spaced from both of the rods and includes structure for successively forming and delivering individual portions of the comestible material, as well as an input for the comestible material. 
         [0018]    A shiftable plate is located between the injection rod and the cooking tube open end and has a plug seating and injection bore, a material conveying bore, and a material delivery bore. Shifting mechanism is coupled with the plate for selective shifting thereof between a first position wherein the seating and injection bore is aligned with the seating rod, and the material delivery bore communicates the portioning assembly with the tube inlet, and a second position wherein the seating and injection bore is aligned with the injection rod and the tube inlet, and the material conveying bore communicates the input and the portioning assembly. An operating mechanism is coupled with the plate shifting mechanism, the seating rod, the injecting rod, and the portioning assembly. This serves to shift the plate to the first position thereof and to cause (a) shifting of the seating rod to shift a plug from the plug delivery location and into the seating and injection bore of the plate, and (b) to operate the portioning assembly in order to deliver a portion of the material to the tube inlet. The operating mechanism also subsequently shifts the plate to the second position thereof and causes (c) shifting of the injection rod to shift the seated plug from the seating and injection bore and into the tube through the tube inlet, and (d) to operate the portioning assembly to create a portion of the material for subsequent delivery to the cooking tube behind the injected plug. 
         [0019]    The preferred systems of the invention are provided with an output conveyor for finished product also having a spray assembly for the application of liquids to the cooked products, in order to increase the palatability thereof, and to facilitate downstream additional processing or packaging. A plug recovery assembly is also provided in order to recover plugs from the output conveyor and to direct these plugs for reuse; if desired, the plugs may be washed during recovery thereof. 
         [0020]    An additional feature of the invention is the provision of a plug storage assembly, which is an adjunct of the plug recovery assembly. The storage assembly is operable to create accumulated rows of plugs from the discharge station and to successively move such rows onto a receiving rack. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  is a perspective view of a processing system in accordance with the present invention, operable for the batch-continuous production of elongated, sausage-type products, and viewing the input end of the system; 
           [0022]      FIG. 2  is another perspective view of the processing system of  FIG. 1 , but viewing the output end thereof; 
           [0023]      FIG. 3  is an end elevational view of the processing system, viewing the input end thereof; 
           [0024]      FIG. 4  is an end elevational view of the front face of a gate assembly forming a part of the input end of the processing system, and supporting the plug and meat emulsion injection assembly; 
           [0025]      FIG. 5  is a perspective view of the plug and meat emulsion injection assembly of  FIG. 4 , viewing the rear face thereof; 
           [0026]      FIG. 6  is a fragmentary, perspective view of the plug and meat emulsion injection assembly of  FIGS. 4 and 5 , viewing downwardly from the top thereof; 
           [0027]      FIG. 7  is a fragmentary, vertical sectional view of the plug and meat emulsion injection assembly of  FIGS. 4-6 ; 
           [0028]      FIG. 8  is an exploded, perspective view of the plug and meat emulsion injection assembly; 
           [0029]      FIG. 9  is a fragmentary, vertical sectional view of a portion of the plug and meat emulsion injection assembly, and illustrating delivery of plugs to a plug magazine; 
           [0030]      FIG. 10  is a fragmentary, exploded, perspective view depicting one of the magnetic plug pickups forming a part of the plug and meat emulsion injection assembly; 
           [0031]      FIG. 11  is a perspective sectional view of one of the magnetic pickups; 
           [0032]      FIG. 12  is an end elevational view of the input end of the processing system, with the gate assembly removed and illustrating the input end of the cooking drum; 
           [0033]      FIG. 13  is a vertical sectional view of the cooking drum of the system, taken at a central location; 
           [0034]      FIG. 14  is another vertical sectional view of the cooking drum, at a location closer to the inlet end of the drum, as compared with  FIG. 13 ; 
           [0035]      FIG. 15  is an fragmentary, sectional view illustrating the operation of the cooking drum indexing device operable to incrementally rotate the drum during operation of the processing system; 
           [0036]      FIG. 16  is a perspective view of internal components of the cooking drum; 
           [0037]      FIG. 17  is an enlarged, fragmentary, sectional view illustrating the steam injection assembly forming a part of the cooking drum; 
           [0038]      FIG. 18  is a plan view of the plug storage racks of the processing system; 
           [0039]      FIG. 19  is a perspective view of one of the storage racks, and illustrating plug-holding supports for both small and large plugs; 
           [0040]      FIG. 20  is a perspective view of a plug storage rack, viewing the underside thereof; 
           [0041]      FIG. 21  is an end elevational view of a plug storage rack; 
           [0042]      FIG. 22  is a fragmentary perspective view illustrating the progression of plugs through the plug storage assembly and into the plug and meat emulsion injection assembly; 
           [0043]      FIG. 23  is a fragmentary perspective view similar to that of  FIG. 22 , but illustrating the initial operation of plug storage; 
           [0044]      FIG. 24  is a fragmentary, vertical sectional view illustrating the second step of plug storage, wherein a row of plugs is elevated and delivered to the plug conveyor; 
           [0045]      FIG. 25  is a fragmentary, vertical sectional view similar to  FIG. 24 , illustrating the completion of plug storage with the storage rack lowered; 
           [0046]      FIG. 26  is a perspective view of the output assembly forming a part of the processing system; 
           [0047]      FIG. 27  is an end view of the output assembly; 
           [0048]      FIG. 28  is a vertical sectional view depicting the configuration of the plug and meat emulsion injection assembly in the standby position thereof while the cooking drum is indexed; 
           [0049]      FIG. 29  is a sectional view similar to that of  FIG. 28 , depicting the configuration of the plug and meat emulsion injection assembly during an initial plug injection sequence; 
           [0050]      FIG. 30  is a sectional view similar to that of  FIG. 29 , depicting the configuration of the plug and meat emulsion injection assembly during drawing of a charge of meat emulsion and injection of a plug into a cooking tube; 
           [0051]      FIG. 31  is a sectional view similar to that of  FIG. 30 , depicting the configuration of the plug and meat emulsion injection assembly during injection of a charge of meat emulsion into the cooking tube behind the previously injected plug; 
           [0052]      FIG. 31A  is a fragmentary sectional view illustrating an alternative embodiment wherein a source of pressurized air is directed against the leading forming plugs within the cooking tubes during loading of the tubes with plugs and meat emulsion portions, and/or during cooking of the meat emulsion; 
           [0053]      FIG. 32  is a sectional view similar to that of  FIG. 31 , depicting the configuration of the plug and meat emulsion injection assembly during injection of a second plug behind the previously injected emulsion charge and within the delivery tube; 
           [0054]      FIG. 33  is a sectional view similar to that of  FIG. 32 , depicting the configuration of the plug and meat emulsion injection assembly during insertion of the second plug into the cooking tube behind the previously injected emulsion charge; 
           [0055]      FIG. 34  is a sectional view of the meat emulsion delivery block and illustrating the connection thereof to a pair of emulsion cylinders forming a part of the plug and meat emulsion injection assembly; 
           [0056]      FIG. 35  is a fragmentary sectional view illustrating a pair of delivery tubes forming a part of the plug and meat emulsion injection assembly, with the delivery tubes mated with corresponding cooking tubes of the cooking drum; 
           [0057]      FIG. 36  is a view similar to that of  FIG. 35 , but illustrating the alternate use of larger diameter cooking tubes for the production of differently sized end products, as compared with  FIG. 35 ; 
           [0058]      FIG. 37  is an enlarged, vertical sectional view illustrating a plug injected into one of the delivery tubes; 
           [0059]      FIG. 38  is a greatly enlarged, fragmentary sectional view depicting the plug-retaining shoulder of the delivery tube; 
           [0060]      FIG. 39  is an enlarged sectional view of the input end of a cooking tube; 
           [0061]      FIG. 40  is a fragmentary, enlarged sectional view illustrating the plug-retaining should of the input end of the cooking tube; 
           [0062]      FIG. 41  is a fragmentary sectional view illustrating the operation of the water eject assembly forming a part of the processing system; 
           [0063]      FIG. 42  is a fragmentary, sectional view illustrating the components of the oil application assembly forming a part of the processing system, with the oil injection system in its standby mode; 
           [0064]      FIG. 43  is a fragmentary, vertical sectional view illustrating an air cushion assembly at the outlet end of a cooking tube; 
           [0065]      FIG. 44  is a view similar to that of  FIG. 42 , but showing the oil application assembly in operation during injection of oil into the cooking tubes; 
           [0066]      FIG. 45  is a fragmentary, vertical, sectional view illustrating components of the oil application assembly; 
           [0067]      FIG. 46  is a fragmentary sectional view illustrating the end seal arrangement in the oil application assembly; 
           [0068]      FIG. 47  is a sectional view illustrating the output end of the cooking tubes and the product and plug delivery assembly, with the latter in a standby mode during indexing of the cooking drum; 
           [0069]      FIG. 48  is a view similar to that of  FIG. 47 , but illustrating the product and plug delivery assembly engaged with the output ends of the cooking tube, during delivery of cooked products and plugs; and 
           [0070]      FIG. 49  is a fragmentary, sectional view illustrating an alternate, spring-biased cooking tube embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0071]    Turning now to the drawings, a processing system  50  is illustrated in  FIGS. 1 and 2 . The system  50  presents an input end  52  and an output end  54 , and broadly includes a cooking drum assembly  56 , a gate assembly  58  at the input end  52  supporting a control panel  60 , a forming plug and meat emulsion injection assembly  62 , and a water ejection assembly  63 . A cooked product output conveyor  64  is situated adjacent output end  54 , along with a finished product and plug delivery assembly  65 , a plug recovery assembly  66 , and an oil application assembly  68 . A plug storage assembly  69  is situated above cooking drum assembly  56 , as shown. The system  50  is designed to produce elongated, cooked, commercially acceptable sausage-type products on a continuous basis without the use of casings. In the system  50 , the assembly  62  defines a loading station, whereas assemblies  63  and  65  and conveyor  64  cooperatively define a discharge station. 
       Cooking Drum Assembly  56   
       [0072]    In more detail, the cooking drum assembly  56  includes an elongated, axially rotatable, cylindrical housing  70  supported on a frame assembly  72 . The latter has upright corner posts  74  with interconnecting lateral frame members  76 ,  78  and a pair of upright central posts  80  at each end of the frame assembly. The housing  70  comprises an outer wall  71 , an inner wall  84 , with end spacers  105  (see  FIGS. 41-42 ) and intermediate spacers  85  interconnecting the walls  71 ,  84 . Thermal insulation  82  is situated between the walls  71 ,  84  (see  FIG. 41 ). A series of temperature probes  86  are mounted on housing  70  and extend into the interior of the housing  70 , along with a steam vent  91 . The vent  91  can be opened in order to allow filling of the housing  70  with water. 
         [0073]    Internally, the assembly  56  has a plurality of radially extending, circumferentially spaced apart tube arrays  92 . Each such array is made up of two smaller diameter cooking tubes  94  and two larger diameter cooking tubes  96 . Each tube has an inlet end presenting an inwardly extending, plug-retaining shoulder  97  (see  FIGS. 39-40 ). All of the tubes  94 ,  96  are substantially rectilinear and extend the full length of housing  56 , and are supported by fore and aft annular, apertured plates  98 ,  100 . In addition, two intermediate supporting plates (not shown), identical to the plates  98 ,  100 , are located between the latter. The plates  98 ,  100  and the intermediate plates are in maintained in proper spaced relationship by elongated rigid rods  102 . An elongated, tubular, fixed, central mounting member  104  having fore and aft bearing surfaces  106 ,  108  also extends the full length of the housing  70 . The outboard ends of the mounting member  104  are supported by fittings  110  affixed to the central posts  80  (see  FIG. 12 ). 
         [0074]    A stationary steam injection assembly  112  is positioned within housing  70  and includes a steam injection pipe  114  extending through the forward portion of mounting member  104  and terminating in an injection manifold  116  ( FIG. 17 ). The manifold  116  supports a total of four radially extending, circumferentially spaced steam delivery stems  118  in communication with pipe  114 ; each stem  118  has a check valve  119  therein to prevent backward flow of water into the steam injection assembly  112 . The stems  118  are operably coupled with a total of four elongated, axially extending steam tubes  120  within housing  70  and having apertures for delivery of steam throughout the entire lengths thereof. The ends of the tubes  120  are supported on circular mounts  122 , which are in turn secured to mounting member  104 . 
         [0075]    The ends of the housing  70  are defined by solid, apertured fore and aft bulkheads  99   a  and  99   b , which have the identical pattern of apertures of the corresponding plates  98 ,  100  (see FIGS.  2  and  12 - 14 ). The bulkheads also have a solid section  124  inboard of the arrays  92 , equipped with central nylon bearings engaging the bearing surfaces  106 ,  108 . The bulkheads  99   a ,  99   b  are secured to housing  70  by means of threaded fasteners extending through the bulkhead margins and coupled with internal spacer rings  105 . 
         [0076]    Referring to  FIGS. 12-14 , the input bulkhead  99   a  is provided with an integral, annular indexing ring section  126  having a series of outermost teeth  128 . An indexing drive  130  is mounted to the forward portion of frame assembly  72 , and has a pivotally mounted pneumatic actuating cylinder  132  with an extendable rod  134  terminating in a fixture  136  complemental with teeth  128  ( FIGS. 14-15 ). A pivotal locking element  137  serves to hold the housing  70  in place between indexing movements thereof. A total of three dual roller guides  138  are secured to the forward corner posts  74  and engage indexing ring section  126  in order to assure smooth rotation of the cooking drum. It will be appreciated that the ring  126  and drive  130  provide a mechanism for incremental shifting of the housing  70  and thus tubes  94 ,  96 . 
         [0077]    Referring now to exemplary cooking  FIG. 35 , an array  92  of cooking tubes  94 ,  96  is illustrated, along with the associated sealing structure. Specifically, at the forward end of the array  92 , an apertured sealing block  140  is provided secured by fasteners  141  to bulkhead  99   a . The sealing block  140  is equipped with sealing rings to provide a watertight seal. The aft end of the tube array  92  is likewise provided with an identical sealing block  140  (see  FIG. 41 ) in order to provide the same type of seal. In practice, each of the sealing blocks  140  is used to seal a pair of adjacent tube arrays  92 . 
         [0078]    Referring to  FIG. 49 , an alternate embodiment is illustrated. In this case, the cooking tubes, such as exemplary cooking tube  96   a , are shiftable during operation of the processing system. Accordingly, the cooking tubes are sealed by means of a sealing block  140   a  secured to bulkhead  99   b  by fasteners  141   a . In addition, it will be observed that a biasing spring  144  is positioned about the aft end of tube  96   a  and abuts the rear sealing block  140   a , which biases the outer ends of the tube away from bulkhead  99   a . The spring  144  is within a housing  146 , which is secured between a connecting ring  148  and the fasteners  141 . The rearmost end of tube  140  has a bevel  150 , as shown. A tubular, beveled actuator  150   a  is designed to mate with bevel  150  during operation of the alternate embodiment, as will be described. As also depicted in  FIG. 49 , the bulkheads  99   a ,  99   b  are secured to housing  70  by means of annular endmost connector rings  152  secured to the inner surface of the housing and which receive threaded fasteners (not shown). 
       Gate Assembly  58   
       [0079]    Referring to  FIGS. 5-7 , the gate assembly  58  supports control panel  60  as well as the plug and meat emulsion injection assembly  62 . The gate assembly includes a rigid box frame  154  having uprights  158  with upper and lower crosspieces  160 ,  162 . In addition, the gate assembly  58  has an adjustment mechanism  164  having a pair of stationary, inclined frame tubes  166 ,  168  each having a pair of spaced-apart clamping screws  170 ,  172  ( FIG. 5 ). The upright  158  is equipped with a pair of latching elements  174  which mate with latches  175 , attached to the right-hand corner post  74 , as viewed in  FIG. 3 . An elongated pivot rod  176  extends between and is secured to the upper and lower crosspieces  160 ,  162  with the outermost ends of the rod  176  secured to the left-hand corner post  74  by couplers  177 , as viewed in  FIG. 3 . In this fashion, the entire gate assembly  58  can be moved between a closed, operating position adjacent the input end of the cooking drum, or to an open position allowing access to the cooking drum. 
         [0080]    The control panel  60  is secured between the upper and lower crosspieces  160 ,  162  by means of standoff connectors  178 . The control panel  60  is itself conventional, and includes the usual digital control components for system  50 . It also receives inputs from the sensors described below. 
       Forming Plug and Meat Emulsion Injection Assembly  62 —Plug Handling Subassembly  180   
       [0081]    Referring to  FIGS. 5-6 , the plug and meat emulsion injection assembly  62  broadly includes a plug handling subassembly  180  and a plug and meat emulsion injection subassembly  182 . The subassembly  180  has a pair of identical, right- and left-hand plug elevators  184  leading to a common, generally V-shaped plug magazine  186 . Each of the elevators  184  is connected to upper crosspiece  160  by connection blocks  185  and has a continuous roller chain  188  trained about upper and lower sprockets  190  and powered by motor  192 .  FIGS. 9-11  depict chain guard structure  189  is provided about the roller chain  188 , as shown. Each link of the roller chain  188  supports a laterally extending lug  194 . Every other lug carries a magnetic plug pickup  196  with intervening lugs supporting blanks  198 . Referring to  FIGS. 10 and 11 , it will be seen that each pickup  196  includes a mounting plate  200 , a circular magnet  202 , and a plug cradle  204 , these components secured together via screws  206 . Each of the pickups  196  is operable to engage and hold a plug  208  delivered to the corresponding elevator by the plug recovery subassembly described below. The delivered plugs  208  are carried downwardly by the moving chain  188  and the pickups  196  to the magazine  186 . The magazine  186  has a pair of upright, obliquely oriented channels  210 ,  212 , extending upwardly from a common base  213 ; each of the channels  210 ,  212  has an inlet throat  214  and a lower, elongated, tubular plug outlet passageway structure  215  separate from base  213  and attached thereto; the passageway structure  215  is in registry with an opening  215   a . Each throat  214  presents a plug detachment segment  216 . 
         [0082]    In order to provide enhanced automated control, the channels  210 ,  212  are each provided with upper and lower proximity sensors  210   a ,  210   b . These sensors are operable to sense the presence of plugs  208  within the respective channels, and to monitor the plug output through the lower outlet passageway structures  215 . 
       Forming Plugs  208   
       [0083]    The preferred forming plugs  208  are illustrated in  FIGS. 37 and 38 . Each plug  208  has a central metallic body  218  presenting an outermost cylindrical surface  220 . The body  218  is formed of an appropriate metal for magnetic handling of the plugs. In addition, the plugs  208  have endmost resilient synthetic resin caps  222 , which are fastened to body  218  and have concave outboard surfaces  224 . If desired, the surfaces  224  may be configured with elongated projections, so that the final formed product may exhibit the appearance of casing wrinkles found in conventionally-produced hot dog products, for example. Additionally, each of the caps  222  have an outer periphery  226 , which is slightly greater than the diameter of the corresponding cooking tubes. It will be appreciated that differently sized plugs are provided for use with the smaller and larger diameter cooking tubes  94  and  96 . The illustrated plugs  208  are for use with the smaller diameter cooking tubes  94 . 
       Plug and Meat Emulsion Injection Subassembly  182   
       [0084]      FIG. 8  illustrates the assembly  182 , including an upright injector support plate  228 , which is secured to a slide frame  230 , the latter being attached to the gate assembly frame tubes  166 ,  168 . The slide frame  230  includes slotted upper and lower frame members  232  and  234 , as well as spaced apart uprights  236 ,  238  (see  FIG. 5 ). The screws  170 ,  172  forming a part of the gate assembly secure the slide frame  230 , and thus plate  228 , in alternate positions. A total of four apertured support blocks  240  are attached to the uprights  236 ,  238 . 
         [0085]    The plate  228  is shiftable fore and aft by means of four pancake cylinders  244 , each having and extendable rod  246 . The position of the pancake cylinders  244  is monitored by way of proximity sensors  245  ( FIG. 6 ). Each rod  246  extends through a corresponding support block  240  and is secured to plate  228  by bolts  248 . The upper and lower pairs of pancake cylinders  244  are interconnected by means of respective support channels  250 ,  252 . The channels  250 ,  252  each have an elongated support legs  254 , which are affixed to the slide frame  230  and uprights  236 ,  238 . A total of four rigid mounting rods  256  are also secured to the plate  228  and extend therefrom. The outermost end of each rod  256  is provided with a clamping sleeve  258  and a threaded, rotatable clamping knob  260 . 
         [0086]    The plate  228  has two lower meat emulsion delivery openings  262  therethough, as well as a pair of plug and meat injection openings  264 . The openings  264  are designed to receive tubular delivery elements  265 , each having a beveled outlet end  265   a  equipped with a sealing ring  265   b  (see  FIG. 37 ). The inlet end of each element  265  has an annular, inwardly extending, plug-retaining shoulder  265   c  ( FIGS. 37-38 ). The elements  265  are changed when different diameter products are being produced, as explained below. The plate  228  further has a pair of spaced apart keyhole openings  266  designed to receive respective vacuum fittings  268 . 
         [0087]    The rods  256  support a pair of upright plates  270 ,  272 . Plate  270  includes a pair of vertical, apertured spacers  274 , and also has a series of openings through the plate between the spacers  274 . In particular, the plate  270  has a pair of plug and meat emulsion injection openings  276 , a lower pair of meat emulsion delivery openings  278 , each equipped with a stationary, tubular, projecting fitting  279 , and a pair of vacuum openings  280 , which receive the fittings  268 . It will be observed ( FIG. 28 ) that the vacuum openings  280  communicate with the opposite face of the plate  270 . 
         [0088]    The plate  272  has a pair of upper plug-receiving openings  286  equipped with entry ferrules  288 , and a pair of lower meat emulsion conveying openings  290  with tubular beveled inserts  292  therein. The plate  272  also has a pair of injector rod openings  294  between the openings  286  and  290 , and a pair of vacuum openings  296  equipped with vacuum fittings  298 . The vacuum openings  296  communicate with the opposite face of plate  272 . The face of plate  272  remote from plate  270  is provided with attachment screws  304 ,  306  to permit attachment of actuating cylinder structure, as described below. 
         [0089]      FIG. 8  also illustrates a vertically shiftable injection head assembly  308  is located between the plates  270  and  272 , and broadly includes an apertured and internally slotted plate  310  and a pneumatic actuating cylinder  312 . The cylinder  312  is secured to the upper ends of the plates  270 ,  272 , and has a downwardly extending rod  314  threaded into the upper end of plate  310 . The plate  310  has a pair of lower meat emulsion conveying openings  316  and a corresponding pair of vertically offset, upper meat emulsion conveying openings  318 , with each pair of openings  316 ,  318  connected via an internal oblique passageway  320 . Additionally, the plate  310  has a pair of through openings  322  above the openings  316 , and a pair of plug injection openings  324  with internal tubular inserts  326  therein. 
         [0090]      FIG. 28  illustrates a number of pneumatic actuating cylinders secured to plate  272 , including a pair of meat emulsion portioning cylinders  328  aligned with the openings  290  and secured in place by the fittings  304 , and a pair of plug injection cylinders  330  aligned with the openings  294  and secured by the fittings  306 . Each cylinder  328  includes a shiftable rod  332  supporting a plunger head  334  equipped with sealing structure  336 . A surrounding housing  338  extends between the base of the cylinder  328  and fitting  304  and defines a fluidtight portioning chamber  340 . As shown, the plunger  334  sealingly engages the housing  338  and also, in the extended position thereof, sealingly engages the associated beveled insert  292 . The stroke of rod  332  is adjustable by means of stroke length control mechanism  342 . Each cylinder  330  has a shiftable rod  344  terminating in a rounded end  346  which, in the retracted position thereof, is seated within the associated fitting  306  and the opening  294 . 
         [0091]    A pair of plug injection seating rods  348  are located in registry with the openings  215   a  and are supported by a crosspiece  350 . A small pneumatic actuating cylinder  352  having extensible rod  354  is secured to crosspiece  350  in order to simultaneously move the rods  348 . Cylinder  352  is supported on an elongated bracket  356  secured to plate  272 . 
         [0092]    As best viewed in  FIG. 6 , the V-shaped magazine  186  is mounted on the bracket  356  and also rests upon the upper set of rods  256 . Moreover, in the operating condition of assembly  182 , the clamping sleeves  258  and knobs  260  serve to hold the components of the assembly together, i.e., the sleeves  258  bear against the adjacent face of plate  272 . 
         [0093]    The assembly  282  also has a meat emulsion delivery unit  358  operable to deliver meat emulsion from a pressurized source to the system  50 . Preferably, the meat emulsion is generated by a Marlen twin piston pump, although any suitable food pump may be used. The unit  358  includes a primary emulsion conduit  360  with an upstanding delivery pipe  362  ( FIG. 12 ). An elbow conduit  364  is secured to pipe  362  and in turn is coupled with a meat delivery block  366 . The block  366  is affixed to the face of plate  228  adjacent the cooking drum, and has a pair of outlet openings  368  connected by passageway  370  and communicating with conduit  364 . The outlet openings  368  mate with the fittings  279  to provide a liquidtight seal ( FIGS. 28 and 34 ). 
       Water Ejection Assembly  63   
       [0094]    The ejection assembly  63  includes a water block  372  having a pair of water inlets  374  and a corresponding pair of tubular water outlets  376 . Each outlet  376  is equipped with an o-ring seal  378  ( FIGS. 5 ,  8 , and  41 ). The block  372  is secured to plate  228  by means of attachment pin  380  and a vertical locating pin  381  (see  FIG. 41 ) allowing replacement of the block when different sized products are being produced. The assembly  63  serves to remove cooked products and forming plugs  208  from the cooking tubes by injection of hot water or oil, as will be explained below. 
       Output Conveyor  64   
       [0095]    Referring to  FIGS. 2 ,  26 , and  27 , the output conveyor  64  includes a frame  382  and an elongated, endless, draining wire conveyor belt  384 . The frame  382  is designed to be bolted to the output end of frame  72 . The belt  384  is powered by means of motor  388  and is operable to deliver cooked product to the outlet end  390  thereof. One or more intermediate spray heads (not shown) are positioned above belt  384  and beneath a spray housing  392 . The spray head(s) are operably coupled with a pump  394  in order to deliver liquid (e.g., vinegar) to the heads from a storage tank  398 . In addition, an oil pump  396  is provided, along with an oil tank  400 , in order to supply vegetable oil to the assembly  68 . 
         [0096]    A trough  432  extends the full length of conveyor  64  below the lower run of belt  384  and has three section sections: a first water collection section adjacent the forward end of the frame  382 ; a second vinegar collection section separated from the first section by a baffle plate; and third section separated from the second section by another baffle plate and terminating at an open end adjacent output end  390  of the conveyor. The first water collection section of the trough  432  has an oblique discharge outlet  434 . The outlet  434  is typically equipped with a discharge hose or similar device for water disposal purposes. The second vinegar collection section also has an outlet similar to the outlet  434 . 
       Finished Product and Plug Delivery Assembly  65   
       [0097]      FIG. 28  illustrates the finished product and plug delivery assembly  65  comprising mechanism  402  mounted on frame  382  and operable to successfully deliver cooked products and plugs onto belt  384 . The mechanism  402  includes a block  404  secured to a shiftable plate  406 . The plate is in turn supported by a pair of pancake cylinders  408  affixed to frame  382 . The block carries an array  410  of four tubular outlets  412 - 418  sized and designed to mate with an array  92  of cooking tubes. The input ends  419  of the outlets  412 - 418  are situated within an enlarged opening  419   a  and present a beveled surface  420  (see  FIGS. 43 and 47 ), whereas the outlet ends thereof closely overlie the upper run of belt  384 . A common bore  422  is provided for the outlets  412 - 418 , located to communicate with the corresponding enlarged opening  419   a . An air inlet fitting  424  is secured to block  404  and communicates with the bore  422 , so as to maintain a slight positive pressure within the openings  419   a . This gives a slight cushioning effect when the input ends  419  mate with the corresponding cooking tubes  94 ,  96 . 
         [0098]    The block  404  and tubes  412 - 418  are shiftable between a standby position ( FIG. 47 ) and an operating position ( FIG. 48 ). A series or proximity sensors  426  are secured to block  404  in order to count the plugs  208  from the tube array. In addition, a proximity sensor  430  is provided so as to monitor the position of the pancake cylinders  408 . 
       Plug Recovery Assembly  66   
       [0099]    The plug recovery assembly  66  includes a driven wire belt  438  having an inclined stretch and a horizontal stretch. The belt  438  is trained about a lower roller  440  and a mating upper roller (not shown). The roller  440  has a magnetic core serving to magnetically pick up the plugs  208  as they travel along the length of belt  438  after exiting mechanism  402 , and thus separates the plugs from the finished product. The plugs are then conveyed upwardly and horizontally as shown. A portion of the belt  438  passes through the housing  442  where a wash/drain assembly is provided for washing the plugs as they travel through the housing  442 . This wash/drain assembly is an optional feature of the system  50 . 
         [0100]    A pair of laterally spaced apart plug conveyors  450 ,  452  are provided downstream of the horizontal stretch of belt  438  and receive the plugs from the latter. Each conveyor  450 ,  452  has a pair of vertically spaced apart forward rollers  454 , a rearmost driven roller  456 , and an idler roller  458 . A motor  460  is provided to power each of the belts  450 ,  452 . The upper runs  450   a ,  452   a  convey the plugs  208  toward and into the corresponding elevators  184 , where they are picked up by the magnetic pickups  196  carried on the roller chains  188  (see  FIG. 18 ). 
       Oil Application Assembly  68   
       [0101]      FIG. 42  illustrates the assembly  68 , which is designed to deposit a thin film of a 2:1 volumetric mixture of lecithin and vegetable oil along the inner surfaces of each of the cooking tubes  94 ,  96  prior to filling thereof. The assembly  68  is carried adjacent the front end of conveyor frame  382 , and includes a synthetic resin block  462  secured to a cross plate  464 , the latter being supported by a pair of pancake cylinders  466  attached to the frame  382 . The block  462  has four laterally spaced apart bores, with two of the bores  468  in alignment with and sized for communication with the smaller diameter tubes  94  of a tube array  92 ; the other two bores  470  are in alignment with and sized for communication with the larger diameter tubes  96  of the array  92 . The inlet ends  472  of the bores  468  are configured to mate with the output ends of the tubes  94 , and similarly the inlet ends  474  of the bores  470  mate with the output ends of the larger diameter tubes  96 . Four rearwardly extending oil tubes  476 - 482  are secured to the rear face of block  462 , and communicate with the bores  468 ,  470 . As best seen in  FIGS. 42 and 44 , the oil tubes  476  and  480  are of large diameter, while the tubes  478  and  482  are of smaller diameter. 
         [0102]    An elongated rod assembly is situated within each of the tubes  476 - 482  and includes a forward most swab piston  484  associated with the larger diameters tubes  476  and  480  and a smaller diameter piston  486  associated with the smaller diameter tubes  478 ,  482 . Elongated rods  488  extend rearwardly from the swab pistons  484 , and likewise elongated rods  490  extend rearwardly from the swab pistons  486 . Each rod has a piston  487  of appropriate diameter secured to the rearmost end thereof. The tubes  476 - 482  and internal rods  488 ,  490 , are of essentially the same length as the cooking tubes  94 ,  96  and these components extend rearwardly below the lower run of conveyor belt  384 . 
         [0103]    The block  462  includes four oil inlet passageways  492  coupled with nipple  493 , each located adjacent the rear face of a swab piston  484 ,  486 . The block also has four other oil inlet passageways  494  coupled with nipple  495  spaced rearwardly of the corresponding inlets  492 . A stationary, apertured bushing  496  of appropriate diameter is situated within each of the bores  468 ,  470  immediately in front of the rearwardly-extending tubes  476 - 482 . 
         [0104]    In order to maintain automated control, four proximity sensors  498  are provided for the bores  468 ,  470 , and a sensor  500  is provided to sense the condition of the pancake cylinders  466 . 
         [0105]    As best seen in  FIGS. 45 and 46 , the block  462  has an apertured rear plate  508  which receives the tubes  476 - 482 . In order to provide an oil-tight seal about each of the tubes, the block  462  has o-rings  510  and the rear plate  508  is notched as at  512  about each tube. An annular seat  514  is within each notch  512 , and mates with an annular, compressible seal  516 . 
       Plug Storage Assembly  69   
       [0106]    During production runs using the system  50 , the plugs  208  are continuously reused as cooked product is produced. However, at the end of a production run during cleanup, or when a different sized product is to be produced, the plugs  208  are conveniently stored for subsequent use. To this end, a plug storage assembly  69  is provided above the cooking drum assembly  56 , close to the input end thereof. In general, the assembly  69  has a pair of left- and right-hand storage units  518 . Inasmuch as the units are identical, only the lefthand unit  518  will be described in detail. 
         [0107]    In particular, the unit  518  includes a box frame  520  presenting sidewalls  522 ,  524  and an end wall  526 . A pair of transverse shafts  528  and  530  extend along the length of the unit within box frame  520 . Each of the shafts  528 ,  530  has a pair of sprockets  532 ,  534  thereon, which support a pair of laterally spaced roller chains  536 ,  538 . A drive motor  540  is operably coupled with shaft  530  in order to move the roller chains  536 ,  538 . A plurality of elongated, generally L-shaped flights  542  are attached to aligned links of the roller chains  536 ,  538 , and extend the full lateral distance between sidewalls  522 ,  524 . The outwardly extending segments  544  of the flights  542  are sized to engage and convey a row of plugs  208 , as later described. 
         [0108]    The box frame  520  also is equipped with a gate mechanism  546  comprising a pair of individually shiftable gates  548 ,  549 . Each gate  548 ,  549  has a mounting element  550  within a corresponding slot  552  respectively adjacent the inner surfaces of the side walls  522 ,  524 . The gates are individually movable by means of a small pneumatic piston and cylinder assembly  554 ,  555 . In the retracted position of the gate mechanism ( FIG. 22 ), the gates  548 ,  549  are located out of blocking relationship to the belt run  450   a  ( FIG. 25 ). 
         [0109]    The unit  518  also includes a magnetic pickup roller  556 , which is situated adjacent belt run  450   a  and has a row of magnets  558  each operable to pick up a respective plug  208  of a row thereof. The roller  556  is mounted between the gates  548 ,  549  as shown, and rotates by means of motor  560 . An arcuate plug retainer guide wall  562  extends from the periphery of roller  556  remote from belt run  450   a  downwardly to a rack loading location. 
         [0110]    The unit  518  is equipped with a plug rack  564  or  566  for receipt of smaller or larger diameter plugs  208 . The selected rack is supported beneath the roller chains  536 ,  538  by means of a rack elevator assembly  568 . As best seen in  FIGS. 24-25 , the rack  564  presents a series of spaced apart plug-storing recesses  570  extending between the sidewalls  522 ,  524 , as well as corner blocks  525  mounted to the underside thereof. The assembly  568  includes a pair of opposed, depending walls  573  and a crank mechanism  574  operable to selectively raise and lower a rack  564  or  566 . The foreground wall  573  illustrated in  FIG. 20  supports an upstanding rack stop  567 . The mechanism  574  includes a lever  576  mounted on a depending wall  573  and is operated by means of pneumatic cylinder  578 . An elongated pivot rod  580  extends between the walls  573  and is coupled with lever  576 . A pair of linkages  577  are mounted on the outer face of each wall  573  and are coupled with rod  580 . Each linkage includes a coupler  582  secured to the outer end of the rod  580 , with a pair of elongated linkage rods  586  secured thereto. Each linkage rod  586  is in turn connected with a pivotally mounted crank  588  having an outermost adjustment screw  588   a  located below the respective corner blocks  525 . The underside of the unit  518  also has four corner-mounted connection walls  589 , which permit attachment of the unit  518  to frame assembly  72 . As illustrated, the cylinder  578  is secured to the inner surface of one of the walls  589 . 
         [0111]    The unit  518  is also provided with proximity sensors  589   a  to facilitate control thereof during operation, as described below. 
       Operation 
       [0112]    In the ensuing discussion, the production of hot dog products using system  50  will be described, wherein only the small diameter cooking tubes  94  are employed. Hence, the larger diameter tubes  96  are not used for any purpose. For such operation, the gate assembly is closed and latched with slide frame  230  is in the upper position thereof as depicted in  FIG. 5 , and the strokes of the cylinders  328  are adjusted via mechanisms  342  to deliver the proper portions of meat emulsion. Small diameter change parts are also installed, namely the delivery elements  265 , vacuum fittings  268 , water block  372 , plug magazine  186 , entry ferrules  288 , and inserts  326  of plate  310 ; and if the plug storage assembly  69  is to be used, the small plug racks  564  are installed. 
         [0113]    In general, the operation of system  50  involves continuous cooking and plug recovery, with intermittent indexing movement of the cooking drum assembly  56 . When the drum assembly  56  is stationary after each increment of rotation, three individual operations occur substantially simultaneously, namely (1) filling of empty and previously oiled small diameter tubes  94  of an array  92   a  with injection of successive charges of meat emulsion and forming plugs  208 ; (2) oiling of empty tubes  94  in an array  92   b  immediately adjacent and upstream of the array  92   a  being filled; and (3) ejection of cooked product and plugs from the tubes  94  of another array  92   c  spaced two arrays from the array  92   b.    
         [0114]    Cooking occurs owing to the fact that the housing  70  is filled with water, with steam injection into pipe  114 , so that the steam travels through the stems  118  and the steam tubes  120 . This serves to inject steam into the surrounding water so as to heat the latter and thus effect cooking of product within the tubes  94 . The temperature probes  86  are continuously monitored in order to maintain proper cooking temperatures within the housing  70  As indicated, this cooking step occurs continuously during operation of system  50 . 
         [0115]    It is next assumed that the cooking drum has been indexed to a new incremental position by the operation of indexing drive  130 , while the assemblies  63 ,  65  and  68 , and subassembly  182 , are in their standing positions spaced from the ends of the cooking tubes (see  FIGS. 42 and 47 ). This involves operation of cylinder  132  to withdraw fixture  136  from the initial tooth, whereupon the cylinder pivots downwardly in an orientation such that fixture  136  can engage the next tooth. The cylinder is again operated to extend the fixture to engage the next tooth, with consequent pivoting or the locking element  137  until the latter comes into engagement with the initial tooth When the drum is thus indexed, the output ends of the cooking tubes  94  of array  92   c  filled with fully cooked product and intermediate forming plugs  208  are immediately adjacent the finished product and plug delivery assembly  65  (i.e., the output ends of tubes  94  are in alignment with the input ends  419  of the smaller diameter tubular outlets  414 ,  418 ). Additionally, the input ends of the tubes  94  of array  92   c  are immediately adjacent the water outlets  376  of water ejection assembly  63 . The empty tubes  94  of array  92   b  are in alignment with the smaller diameter bores  472  of oiling assembly  68 . Finally, the outlet ends of the empty tubes  94  of array  92   a  are in alignment with the delivery elements  265  of the plug and meat emulsion injection subassembly  182 . 
         [0116]    Next, the pancake cylinders  244  of subassembly  180  are actuated in order to shift the latter towards housing  70  until the open ends of the delivery elements  265  come into mating engagement with the inlet ends of the cooking tubes  94  of array  92   a  ( FIG. 35 ), and the water outlets  376  are similarly engaged with the inlet ends of the tubes  94  of array  92   c  ( FIG. 41 ). At substantially the same time, the pancake cylinders  408  and  466  of the assemblies  65  and  68  are actuated, which serves to shift these assemblies toward the outlet end of the housing  70 . This causes the outlets  414 ,  418  to come into mating engagement with the output ends of the tubes  94  of array  92   c , and the ends of the bores  472  to matingly engage the output ends of the tubes  94  of array  92   b.    
         [0117]    Ejection of cooked product and plugs  208  from the tubes  94  of array  92   c  is accomplished by directing pressurized water from block  372  and outlets  376  into these tubes behind the closest plugs  208  ( FIG. 41 ). The product and plugs  208  thus progressively pass through the tubes  94  and  414 ,  418 , and are ultimately deposited onto moving conveyor  384 . This moves the cooked product away from housing  70  and towards output end  390  of the conveyor for further processing or packaging. If desired, the products may be sprayed with a substance in order to assist with skin formation and/or color development in the cooked product (e.g., acetic acid or white vinegar) or the like in the spray housing  392 . The intermediate plugs  208  are handled by the subassembly as described hereafter. At the end of the product and plug ejection sequence, the water within the tubes  94  of array  92   c  passes out of the tubes and descends though the conveyor  384  where it is collected in trough  432  and disposed of through outlet  434 . 
         [0118]    Oiling of the tubes  94  of array  92   b  is effected by directing a pressurized mixture of lecithin and vegetable oil though the nipple  493  of block  462  for passage through inlets  492  immediately behind the swab pistons  486 . This progressively moves the swab pistons through the length of the tubes  94  ( FIG. 44 ), and simultaneously pulls the rods  490  from the oil tubes  478 ,  482  until the rearmost pistons  487  seat within the block  462  ( FIG. 45 ). At this point the forward faces of the pistons  487  are adjacent the oil outlets  494 . Pressurized lecithin/oil is introduced through the outlets  494 , which causes rearward movement of the pistons  487  and consequent retraction of the rods  490  and swab pistons  486  to the original positions thereof. This in turn creates a very thin film of lecithin/oil on the inner surfaces of the tubes  94  of the array  92   b , which assists in filling thereof with meat emulsion and plugs  208  when the housing  74  is indexed to the next position. It will be appreciated that lecithin/oil application may not be required if the cooking tubes are formed of other types of materials. 
         [0119]    Referring now to  FIGS. 28-33 , the sequential operation of the plug and meat emulsion injection subassembly  182  is illustrated, depicting the filling of the tubes  94  of array  92   a  from the beginning and through a complete cycle. It will be understood in this respect that these tubes have been previously oiled, as described above, and are ready to be filled with the plugs  208  and meat emulsion portions.  FIG. 28  illustrates the subassembly  182  in its standby mode, with a series of plugs  208  located within each of the channels  210 ,  212  of magazine  186 , and with meat emulsion  590  within the passageways of block  366 . 
         [0120]      FIG. 29  illustrates the subassembly  182  in its first operational position with the tubular element  265  operatively coupled with cooking tubes  94 . In addition, this Figure depicts the initial insertion and seating of plugs  208  into the inserts  326  of plate  310 . This is accomplished by appropriate actuation of the cylinder  352 , which shifts the plug injection and seating rods  348  through the corresponding adjacent openings  215   a  and passageway structures  215  in order to shift the lowermost plug  208  within each channel toward and into the inserts  326 . Any residual air present in the leading concavities of the seated plugs  208  is removed by means of a vacuum drawn through fittings  268 . 
         [0121]      FIG. 30  illustrates the next steps wherein the rods  348  have been withdrawn, thereby allowing the next adjacent plugs  208  to descend into loading positions. Further, the plate  310  has been shifted downwardly by actuation of the cylinder  312  to a second position wherein the inserts  326  are in alignment with the tubular elements  265 , and the first stages of the cylinders  330  have been actuated to extend the rods  344  so as to move the initially-seated plugs  208  into the delivery elements  265 . A vacuum drawn through the fittings  298  serves to remove air from the trailing concave face of the previously injected plugs  208 . This downward shifting of the plates  310  also aligns the through-openings  322  with those of plate  310  with the meat emulsion conveying openings  290  of plate  272 , and with the meat emulsion delivery openings  279  of plate  270 . In this fashion, the initial portions or charges of meat emulsion  590  are drawn by actuation of the cylinders  328  into the portioning chambers  340 . 
         [0122]      FIG. 31  illustrates the next steps wherein the plate  310  is shifted upwardly to the position of  FIG. 29 . This has two principal functions. First, the oblique passageways  320  are moved so as to communicate the portioning chambers  340  with the delivery elements  265 , allowing actuation of the cylinders  328  in order to move the previously drawn initial portions of emulsion  590  from the chambers  340  into and through the delivery elements  265  and against the trailing face of the previously injected initial plugs  208 . Second, the passageway  324  with inserts  326  therein are again located for loading of succeeding plugs  208  into the inserts  326 , via the action of the cylinder  352  and rods  348 . 
         [0123]      FIG. 31A  illustrates an additional embodiment wherein pressurized air is directed either continuously or intermittently against the rearward faces of the initially injected plugs  208  during filling of the tubes  94 . As illustrated, a sealing plug and tubular injector assembly are used for air injection, as indicated by the arrow, with the sealing plug operatively engaging the output end of the tube. The pressurized air serves to inhibit any undo forward movement of these plugs away from the adjacent meat portions, owing to the speed of operation of the system  50 . 
         [0124]    It is also contemplated that pressurized air may be injected into the cooking tubes during emulsion cooking, either continuously or intermittently throughout all or a portion of the cooking sequence. This serves to cook the emulsion under positive pressure to assist in product formation. In such a situation, a plurality of the sealing plug and tubular injector assemblies would be positioned adjacent to the output ends of the tubes  94 , and would be shiftable into engagement with the output ends, in the manner of the assemblies  65  and  68 . Hence, during indexing movement of the housing  70 , the sealing plug and tubular injector assemblies would be retracted, and once the housing  70  was indexed to its next position, these assemblies would be moved back into operative engagement with the outlet ends of the tubes  94 . This serves to cook the emulsion portions under compressive pressure within the tubes  94 . 
         [0125]      FIG. 32  illustrates the plate  310  downwardly shifted to the  FIG. 30  position, with the next succeeding plugs  208  being shifted through actuation of the second stages of cylinders  330 , which moves the plugs  208  through the delivery elements  265  and into the cooking tubes  94 . Finally,  FIG. 33  illustrates the plate  310  again shifted so as to allow portions of meat emulsion  590  to be drawn into the portion chambers  340 , for the next step of the tube loading operation. 
         [0126]    It will thus be appreciated that the tubes  94  of array  92   a  will be successively filled with plugs  208  and intermediate portions of meat emulsion. This operation is facilitated by the presence of the thin film of lecithin/oil on the inner surfaces of the tubes  94 . In this fashion, all of the portions are cooked to essentially the same degree. The lecithin/oil coating has been found to facilitate ejection of cooked product from the tubes  94 , without disrupting the skinned surfaces of the products. 
         [0127]    As explained, the steps of filling the tubes  94  of array  92   a , the application of oil to the tubes  94  of array  92   b , and the ejection of cooked product and plugs from the tubes  94  of array  92   c , occur substantially simultaneously. Once these steps are completed for a given set of arrays  92   a - 92   c , the assemblies  63 ,  65 , and  68 , and subassembly  182 , are separated from the ends of the tubes  94  by operation of the associated pancake cylinders, to assume the standby positions thereof. This permits a further indexing operation of the housing  70  using the indexing drive  130 , whereupon the foregoing assemblies and subassemblies are again moved into operative engagement with the tubes  94  and the above steps repeat. 
         [0128]    As the housing  70  is successively indexed and the tubes  94  of the arrays are filled with meat emulsion and plugs, cooking of the emulsion portions within the tubes is carried out. The system  50  is operated so that by the time filled tubes  94  successively reach the ejection assembly  63  and the finished product and plug delivery assembly  65 , the emulsion portions are cooked to the desired degree. 
         [0129]    The plug recovery assembly  66  operates essentially continuously and serves to pick up the plugs  208  from the belt  384  and direct these plugs to the plug elevators  184 . In this regard, two streams of cooked product and plugs  208  are successively deposited upon the conveyor  386 . As the plugs reach the magnetic roller  40 , they are separated from the cooked products and two parallel streams of plugs pass along the conveyor belt  438 . At the end of the belt  438 , the plugs are transferred to the individual conveyors  450  and  452 . This serves to move the plugs  208 , again in separate plug streams, to the respective plug elevators  184  where the plugs are picked up by the magnetic pickups  196 . The plugs then descend through movement of the roller chains  188  until they reach the detachment segments  216  of the channels  210 ,  212  ( FIG. 9 ). This causes the detachment of the plugs  208  from the pickups  196 , allowing the plugs to descend into the channels for reuse, as described. 
         [0130]    As indicated, during production operations of system  50 , the plug storage assembly  69  is not used. However, during system shutdown, for purposes of cleanup or size changeover, the plugs  208  are collected, and assembly  69  is used for this purpose. Accordingly, the proper sized rack  564  or  566  is inserted into each unit  518  by sliding the racks into the spaces above the depending walls  573  until the racks engage the rack stops  567 . Next, the racks are elevated using the assemblies  568  so that the screws  588   a  thereof engage the undersides of the corner blocks  525  and raise the racks to their loading positions in the units  518 . 
         [0131]      FIGS. 24 and 25  illustrate the filling of a rack  564  in a unit  518 . Specifically, the forward gate  549  is first extended, which stops the flow of plugs to the associated plug elevator  184 . Continued movement of the belt  450  causes succeeding plugs  208  to come into abutment and accumulate. This continues until a full row of plugs  208  is collected, whereupon the second gate  548  is actuated to prevent further plugs from entering the unit  518 . 
         [0132]    At this point, the roller  556  is rotated so as to pick up the entire row of plugs  208  between the gates, and to deposit this row onto a flight  542 . As the roller chains  538  continue to move, the transferred row of plugs  208  is moved downwardly along the path of wall  562  until the row of plugs is deposited on the proximal recess provided in the plug rack  564 . This operation is continued and as additional plug rows are created and transferred, the flights  542  move the previously collected plug rows to successive plug recesses spaced from roller  556 . 
         [0133]    When the rack  564  is filled, the rack elevator assembly  568  is actuated to lower the filled rack out of the path of the chain flights  542 , allowing the filled rack to be removed from the unit  518 . Specifically, the assembly  568  is operated to shift the filled rack  564  supported on the screws  588   a  to the lowered position thereof, thereby permitting sliding withdrawal of the filled rack from the unit  518 . 
         [0134]    The above description has focused on the production of smaller diameter hot dog-type products making use of the smaller diameter cooking tubes  94  and related components. When it is desired to produce larger diameter products, the tubes  96  are used and the previously described change parts are installed on the system  50  in lieu of the smaller diameter change parts (see, e.g.,  FIG. 36 ). The slide frame  230  is also shifted to its alternate, lowered position. All other operations in the production of the larger diameter products are the same as those described previously. 
         [0135]    In preferred forms, the tubes  94 ,  96  and all other meat emulsion-conveying components are the system  50  are formed from extruded Teflon. It has been found that this material gives an advantageous balance between cooking efficiency while avoiding problems of sticking and the like, which can degrade the integrity of the finished products. In other instances, however, materials such as stainless steel may be used. 
         [0136]    The provision of plug-retaining shoulders  265   c  on the elements  265 , and shoulders  97  on the cooking tubes  94 ,  96  is important in that it inhibits backward travel of the plugs  208  after insertion thereof. It has been found that without such shoulders, the plugs  208  can migrate backwardly, owing to the pressure conditions within the tubes, and thus disrupt production. The shoulders  265   c  and  97  have been found to mitigate this problem. However, along with the shoulders  97 , positive pressure air or mechanical stops could be employed at the input ends of the tubes  94  after complete filling thereof as an additional means of preventing backward migration of the plugs  208 . In the former case, seal and injector assemblies of the type illustrated in  FIG. 31A  could be employed. 
         [0137]    The preferred embodiment of the invention makes use of cooking tubes  94 ,  96 , which are axially fixed, and operating assemblies  62 ,  63  and  68 , which move axially relative to the cooking tubes between standby and operating positions.  FIG. 49  illustrates an embodiment wherein alternate cooking tubes, such as tube  96   a , are axially shiftable and are provided with a biasing spring  144  serving to urge the cooking tubes rightwardly. In this case, a tube-displacing mechanism including actuator  150   a  is provided to engage the beveled ends  150  of the tubes  96   a . In operation, the mechanism engages the ends  150  and axially shifts the tubes  96   a  against the bias of the springs  144  and into mating engagement with a forward emulsion and plug filling assembly. At the same time, filled tubes  96   a  engage an ejector device which serves to push the contents of the filled tubes rearward and out the tube ends.