Patent Publication Number: US-7906166-B2

Title: Preconditioner having independently driven high-speed mixer shafts

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of application Ser. No. 11/875,033, filed Oct. 19, 2007, which is a continuation-in-part of application Ser. No. 11/551,997, filed Oct. 23, 2006. Both of these prior applications are incorporated by reference herein in their entireties. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is broadly concerned with improved, dual mixing shaft preconditioners of the type used upstream of processing devices such as extruders or pellet mills in the production of animal feeds or human foods. More particularly, the invention is concerned with such preconditioners, and processing systems making use thereof, wherein the preconditioners include variable drive mechanisms operably coupled with the mixing shafts and designed to permit selective rotation of the shafts at individual rotational speeds independent of each other. 
     2. Description of the Prior Art 
     Preconditioners are widely used in combination with extruders for preparing and blending food materials before further processing and cooking of the same in an extruder. For example, products having a relatively high percentage of flour-like material are often blended with water and treated with steam in a conditioner prior to extrusion. Use of preconditioners is particularly advantageous in preparing pet food or similar products comprising quantities of protein and starch. There are a myriad of pet food formulas in today&#39;s market, with widely varying ingredients and quantities thereof. For example, low-calorie pet foods are popular and include very high quantities of starch-bearing materials (e.g., corn and rice). Such low-calorie pet food formulations cannot be subjected to long retention times in a preconditioner, because the starch content thereof tends to become gummy and unsuitable for downstream extrusion processing. On the other hand, standard pet food formulas having far less starch and higher protein contents require long residence times to become properly preconditioned. Therefore, a preconditioner capable of only limited variability of terms of residence times is often not suitable for sophisticated pet food processors. 
     In recent years there has been an increase in the production of extrusion-processed aquatic feeds used in fish farming. Such aquatic feeds have traditionally included large quantities of fish meal (up to about 70% by weight). However, there is a trend away from using such large quantities of fish meals, owing to the cost and availability of such meal. In lieu thereof processors are using greater quantities of high protein plant ingredients such as soy. A problem with these plant protein sources is that most contain significant quantities of anti-nutritional factors, which must be destroyed during processing. This requires the application of moist heat over a period of time, usually in a preconditioner. Many conventional preconditioners are incapable of fully destroying such anti-nutritional factors, which detracts from their usefulness in the context of modern-day aquatic feeds. 
     Conventional preconditioning apparatus often includes an elongated vessel having a pair of identical side-by-side, frustocylindrical, intercommunicated mixing chambers each presenting equal areas in transverse cross sections. Each chamber is provided with mixing bars or beaters radially mounted on the rotatable drive shaft aligned with the longitudinal axis of the chamber, and the beaters have a configuration for longitudinally advancing the product from an inlet end of the vessel toward an outlet end of the same as the materials are swept around the frustocylindrical walls. Also, the beaters of each chamber are configured to alternatively pass the product from one chamber to the other when the materials approach the intersection between the chambers. 
     A series of water inlets are often provided along at least a portion of the length of preconditioning vessels for adding water to the food materials during advancement of the latter longitudinally through the mixing chambers. Obviously, it is highly important that water introduced into preconditioning vessels becomes thoroughly and uniformly blended with materials having a flour-like consistency in order to avoid formation of lumps. Typically, lumps represent a non-homogeneous mixture of the material and water with the material forming the outer surface of the lump receiving the highest percentage of moisture. 
     Proper blending of water with materials having a flour-like consistency requires both appropriate residence time within the conditioning vessel as well as proper mixing or agitation of the materials with water. As such, increasing the rotational speed of the beaters of conventional preconditioners in an attempt to increase agitation within the vessel causes the materials to pass through the vessel at a greater speed which correspondingly reduces the residence time of the materials within the vessel to values that may be unacceptable. On the other hand, reducing the rotational speed of the beaters to increase residence time within the vessel adversely affects the mixing characteristics of the vessel to the point where proper blending of the materials with water is not achieved. Increasing the overall length of the vessel is not desirable because of mechanical problems associated with the mixing shafts. 
     Moreover, the structural nature of conventional preconditioning apparatus does not lend itself to flexibility of operation where it is desired, for example, to use one apparatus for processing different materials at varying flow rates. That is, temporarily increasing the length of the apparatus with modular vessel sections in an attempt to increase residence time of materials within the vessel is not a satisfactory solution due to the inherent weight and structural characteristics of the apparatus as well as the predefined material inlets and outlets which are often located at specified positions to pass the materials from one processing stage to the next. As such, it would be desirable to provide a means for varying the residence time of materials passing through a preconditioning apparatus to enable the latter to process different types of materials at optionally varying flow rates. 
     U.S. Pat. No. 4,752,139 (incorporated by reference herein) describes a class of preconditioners having differently-sized, arcuate mixing chambers with a mixing shaft along the center line of each chamber. The mixing shafts include radially-extending, intercalated mixing elements. In the preconditioners of the &#39;139 patent, the shafts are powered through a single drive motor, using appropriate gearing to maintain a constant speed differential (usually 2:1) between the mixing shafts. These preconditioners are commercialized by Wenger Mfg. Co. of Sabetha, Kans. and have proven to be a significant improvement in the art by increasing system through-puts without corresponding additional operating costs. However, the fixed speed differential design of the preconditioners of the &#39;139 patent can sometimes represent an operational drawback by limiting the range of operational parameters which may otherwise be desirable. 
     SUMMARY OF THE INVENTION 
     The present invention overcomes the problems outlined above and provides dual shaft preconditioners capable of independent shaft rotational speeds. Broadly, the preconditioners of the invention comprise an elongated mixing vessel having a material inlet and a material outlet, with a pair of elongated mixing shafts each having a plurality of mixing elements, the shafts located in laterally spaced apart relationship within the vessel. A pair of variable drive mechanisms respectively are coupled with the shafts in order to permit selective rotation of the shafts at individual rotational speeds independent of each other. Such shaft rotation is controlled by means of a control device operably coupled with the drive mechanisms to independently control the rotational speed of the shafts. 
     In preferred forms, the preconditioner mixing vessel includes a pair of arcuate, juxtaposed, intercommunicated chambers of different cross-sectional areas, each equipped with a mixing shaft substantially along the center line thereof. In addition, the preconditioner is preferably supported on a weighing device to weigh the contents of the preconditioner during use thereof thereby affording a means to readily alter the material retention time within the preconditioner. The weighing device is normally in the form of a plurality of load cells operatively coupled with the preconditioner control device. 
     In alternate forms, the preconditioner may be of the type having juxtaposed, intercommunicated chambers of the same cross sectional area, each equipped with a mixing shaft along the centerline thereof. This type of preconditioner may also be equipped with weighing devices so as to facilitate easy changes of retention time. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a somewhat schematic plan view of a preconditioner in accordance with the invention; 
         FIG. 2  is a front elevational view of the preconditioner of  FIG. 1 ; 
         FIG. 3  is a side elevational view of the preconditioner of  FIG. 1 ; 
         FIG. 4  is a sectional view taken along line  4 - 4  of  FIG. 3 ; 
         FIG. 5  is a schematic diagram of the interconnection between the preconditioner of the invention and an extruder; 
         FIG. 6  is a side view of another type of preconditioner in accordance with the invention; 
         FIG. 7  is an end view thereof; 
         FIG. 8  is a plan view thereof; 
         FIG. 9  is a perspective view of another preconditioner embodiment in accordance with the invention; 
         FIG. 10  is a side elevational view of the preconditioner illustrated in  FIG. 9 ; 
         FIG. 11  is a sectional view taken along line  11 - 11  of  FIG. 10 ; and 
         FIG. 12  is a sectional view taken along line  12 - 12  of  FIG. 10 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Embodiment of FIGS.  1 - 5   
     Turning now to the drawings, an improved preconditioner  10  is depicted in  FIGS. 1-4 . Broadly, the preconditioner  10  includes an elongated mixing vessel  12  with a pair of parallel, elongated, axially-extending mixing shafts  14  and  16  within and extending along the length thereof. The shafts  14 ,  16  are operably coupled with individual variable drive devices  18  and  20 , the latter in turn connected with digital control device  22 . The preconditioner  10  is adapted for use with a downstream processing device such as an extruder or pellet mill. As depicted in  FIG. 5 , the preconditioner  10  is coupled with an extruder  24  (which may be of the single or twin screw variety) having an inlet  26  and a restricted orifice die outlet  28 , as well as an internal, axially rotatable screw. 
     In more detail, the vessel  12  has an elongated, transversely arcuate sidewall  30  presenting a pair of elongated, juxtaposed, intercommunicated chambers  32  and  34 , as well as a material inlet  36  and a material outlet  38 . The chamber  34  has a larger cross-sectional area than the adjacent chamber  32 , as will be readily apparent from a consideration of  FIG. 4 . The sidewall  30  has access doors  40  and is also equipped with injection assemblies  42  for injection of water and/or steam into the confines of vessel  12  during use of the preconditioner, and a vapor outlet  44 . The opposed ends of vessel  12  have end plates  46  and  48 , as shown. 
     Each of the shafts  14 ,  16  has a plurality of radially outwardly-extending mixing elements  50  and  52  which are designed to agitate and mix material fed to the preconditioner, and to convey the material from inlet  36  towards and out outlet  38 . It will be observed that the elements  50  are axially offset relative to the elements  52 , and that the elements  50 ,  52  are intercalated (i.e., the elements  52  extend into the cylindrical operational envelope presented by shaft  14  and elements  50 , and vice versa). Although the elements  50 ,  52  are illustrated as being substantially perpendicular to the shafts  14 ,  16 , the invention is not so limited; rather, the elements  50 ,  52  are adjustable in both length and pitch, at the discretion of the user. Again referring to  FIG. 4 , it will be seen that the shaft  14  is located substantially along the center line of chamber  32 , and that shaft  16  is likewise located substantially along the center line of the chamber  34 . 
     The drives  18  and  20  are in the illustrated embodiment identical in terms of hardware, and each includes a drive motor  54 , a gear reducer  56 , and coupling assembly  58  serving to interconnect the corresponding gear reducer  56  and motor  54  with a shaft  14  or  16 . The drives  18  and  20  also preferably have variable frequency drives  59  which are designed to permit selective, individual rotation of the shafts  14 ,  16  in terms of speed and/or rotational direction independently of each other. In order to provide appropriate control for the drives  18  and  20 , the drives  57  are each coupled with a corresponding motor  54  and a control device  60 . The control device  60  may be a controller, processor, application specific integrated circuit (ASIC), or any other type of digital or analog device capable of executing logical instructions. The device may even be a personal or server computer such as those manufactured and sold by Dell, Compaq, Gateway, or any other computer manufacturer, network computers running Windows NT, Novel Netware, Unix, or any other network operating system. The drives  57  may be programmed as desired to achieve the ends of the invention, e.g., they may be configured for different rotational speed ranges, rotational directions and power ratings. 
     In preferred forms, the preconditioner  10  is supported on a weighing device in the form of a plurality of load cells  62 , which are also operatively coupled with control device  60 . The use of load cells  62  permits rapid, on-the-go variation in the retention time of material passing through vessel  12 , as described in detail in U.S. Pat. No. 6,465,029, incorporated by reference herein. 
     The use of the preferred variable frequency drive mechanisms  18 ,  20  and control device  60  allow high-speed adjustments of the rotational speeds of the shafts  14 ,  16  to achieve desired preconditioning while avoiding any collisions between intermeshing mixing elements  50 ,  52 . In general, the control device  60  and the coupled drives  57  communicate with each drive motor  54  to control the shaft speeds. Additionally, the shafts  14 ,  16  can be rotated in different or the same rotational directions at the discretion of the operator. 
     Retention times for material passing through preconditioner  10  can be controlled manually by adjusting shaft speed and/or direction, or, more preferably, automatically through control device  60 . Weight information from the load cells  62  is directed to control device  60 , which in turn makes shaft speed and/or directional changes based upon a desired retention time. 
     The preconditioner  10  is commonly used for the processing of animal feed or human food materials, such as grains (e.g., wheat, corn, oats, soy), meat and meat by-products, and various additives (e.g., surfactants, vitamins, minerals, colorants). Where starch-bearing grains are processed, they are typically at least partially gelatinized during passage through the preconditioner. The preconditioner  10  is usually operated at temperatures of from about 100-212 degrees F., residence times of from about 30 seconds-5 minutes, and at atmospheric or slightly above pressures. 
     The drive arrangement for the preconditioner  10  has the capability of rotating the shafts  14 ,  16  at variable speeds of up to about 1,000 rpm, more preferably from about 200-900 rpm. Moreover, the operational flexibility of operation inherent in the preconditioner design allows for greater levels of cook (i.e., starch gelatinization) as compared with similarly sized conventional preconditioners. 
     Embodiment of FIGS.  6 - 8   
     This embodiment is in many respects similar to that described above, and provides a preconditioner  70  having an elongated mixing vessel  72  with a pair of parallel, elongated, axially-extending shafts  74 ,  76  within and extending along the length thereof. The shaft  74 ,  76  are operably coupled with individual variable drive devices  78 ,  80 , the latter in turn connected with digital control device (not shown) similar to control device  22  described previously. The preconditioner  70  may be used with downstream processing equipment such as extruders or pellet mills. 
     The vessel  72  has an elongated, transversely arcuate sidewall  82  presenting a pair of elongated, juxtaposed, intercommunicated chambers of equal cross sectional area, as well as a material inlet  84  and a material outlet  86 . The sidewall  82  has an access door  88  and is also equipped with injection assemblies  90  for injection of water and/or steam into the vessel  82  during use of the preconditioner. 
     As in the first embodiment, each of the shafts  74 ,  76  has a plurality of outwardly extending mixing elements  92 ,  94  mounted thereon and normally extending the full length of the respective shafts. The elements  92 ,  94  are axially offset and intercalated as illustrated in  FIG. 8 , and are designed to agitate and mix material fed to the preconditioner and to convey the material from inlet  84  toward an out outlet  86 . 
     The drives  78 ,  80  are identical, each having a drive motor  96 , gear reducer  97  and coupler  98 . The drives are preferably variable frequency drives designed to present selective, individual rotation of the shafts  74 ,  76  independently of each other. 
     The preconditioner  70  is supported on a weighing device comprising a plurality of load cells  100  which are operatively coupled with the preconditioner control device. The load cell permits variation in retention time all as described in U.S. Pat. No. 6,465,029. 
     The preconditioner  72  may be used in the same fashion and under the same general operative parameters as described in connection with the embodiment of  FIGS. 1-5 . 
     Embodiment of FIGS.  9 - 12   
     The preconditioner  102  includes an elongated, dual-stage mixing vessel  104  with a pair of parallel, elongated, axially extending and rotatable mixing shafts  106  and  108  along the length thereof. The shafts  106 ,  108  are coupled with individual variable drive devices (not shown), as in the case of the earlier-described embodiments. These variable drive devices are in turn connected to a digital control device, also not shown, The preconditioner  102  is likewise adapted for connection with a downstream extruder or pellet mill. 
     The vessel  104  has an elongated, transversely arcuate sidewall  110  presenting a pair of elongated, juxtaposed, interconnected chambers  112  and  114 , as well as a material inlet  116  and a material outlet  118 . The chamber  114  has a larger cross sectional area than the adjacent chamber  112 , which is important for reasons to be described. Each of the chambers  112 ,  114  is equipped with a series of spaced apart inlet ports  120 ,  122  along the lengths of the corresponding chambers, and an intermediate set of ports  123  is located at the juncture of the chambers  112 ,  114 . These ports  120 ,  122  are adapted for connection of water and/or steam injectors leading to the interiors of the chambers. The overall vessel  104  further has fore and aft end plates  124  and  126 , as well as, a central plate  128 . 
     As illustrated, the shafts  106 ,  108  are essentially centrally located within the corresponding chambers  112 ,  114 . To this end, forward bearings  130  mounted on plate  124  support the forward ends of the shafts  106 ,  108 , and similarly rear bearings  132  secured to plate  126  support the rear ends of the shafts. The shafts  106 ,  108  have rearwardly extending extensions  106   a ,  108   a  projecting from the bearings  132  to provide a connection to the variable frequency drives previously described. 
     The shaft  106  is equipped with a plurality of radially outwardly extending mixing elements  134  located in staggered relationship along the length of the shaft. Each of the elements  134  ( FIG. 12 ) includes a threaded inboard segment  136  received within a correspondingly threaded bore  138  of the shaft  106 , with an outwardly projecting segment  140  having a substantially flat, paddle-like member  142 . As best seen in  FIG. 11 , the paddle members  142  of the mixing elements  134  are oriented in a reverse direction relative to the direction of travel of material from inlet  116  to outlet  118 . That is, these members serve to retard the flow of material through the preconditioner  102 . 
     The shaft  108  situated within smaller chamber  112  likewise has a series of mixing elements  144  along the length thereof in alternating, staggered relationship. The elements  144  are identical with the elements  134 , save that the elements  144  are somewhat smaller in size. Each element  144  presents an outboard paddle-like member  146 . In this case, the members  146  are oriented opposite that of the members  142 , i.e., they are oriented in a forward direction so as to more positively advance the flow of material from inlet  116  toward and out the outlet  118 . 
     As in the case of the earlier described embodiments, adjacent pairs of mixing elements  134  and  144  are axially offset from each other and are intercalated; thus the elements are not of self-wiping design. This allows the shafts to be rotated at greatly different rotational speeds, while avoiding any potential lock-up owing to mechanical interference between the elements  134  and  144 . 
     The preconditioner designs of the present invention permit processing of materials to a greater degree than heretofore possible. For example, prior preconditioners of the type described in U.S. Pat. No. 4,752,139 could not be field-adjusted to achieve different relative rotational speeds between the shafts thereof. That is, in such prior preconditioners, once a rotational speed differential was established during manufacture of the device, it could not thereafter be altered without a complete reconstruction of the device. Normal preconditioners of this type had a speed differential of 2:1 between the shafts within the small and large chainbers, respectively. In the present invention, however, far greater and infinitely adjustable speed differentials can be readily accomplished. Thus, in preferred forms the speed differential between the shafts  106 ,  108  is at least 5:1, and typically ranges from 3:1 to 18:1. This latter differential corresponds to a rotational speed of 900 rpm for the shaft  108 , and 50 rpm for the shaft  106 . 
     This enhanced design affords a number of processing advantages. To give one example, in the prior preconditioner design of the &#39;139 patent, the maximum degree of cook achievable was normally about 30%, with a maximum of about 43% (measured by gelatinization of starch components according to the method described in Mason et al.,  A New Method for Determining Degree of Cook,  67th Annual Meeting, American Association of Cereal Chemists (Oct. 26, 1982), incorporated by reference herein). With the present invention however, significantly greater cook percentages can be achieved, of at least 50% and more preferably at least 55%, and most preferably at least about 75%. At the same time, these enhanced cook values are obtained with the same or even shorter residence times as compared with the prior preconditioners; specifically, such prior designs would require a retention time of from about 160-185 seconds to obtain maximum cook values, whereas in the present preconditioners the retention times are much less, on the order of 120-150 seconds, to achieve this same cook. Further, if the longer typical preconditioner residence times are used, the extent of cook values are normally significantly increased. 
     In one form of the invention, human food or animal feed mixtures containing respective quantities of protein and starch (and normally other ingredients such as fats and sugars) are processed in the preconditioners of the invention to achieve at least about 50%, and more preferably at least about 75% cook values based upon starch gelatinization. Representative examples of such mixtures are pet and fish feeds. The preconditioner of the invention also give enhanced Specific Mechanical Energy (SME) values. Prior preconditioners typically exhibited relatively low SME values whereas the preconditioner hereof have increased SME values of from about 1.7-5.0, more preferably from about 1.9-4.5 kW-Hr/Ton of processed starting materials. 
     It is well understood in the art that increasing the degree of cook in a preconditioner is advantageous in that less energy and retention times are required during downstream processing to achieve a desired, fully cooked product such as a pet food. Thus, use of preconditioners in accordance with the invention increases product throughput and thus materially reduces processing costs. 
     EXAMPLE 1 
     In this Example, a standard dog food formulation was prepared and preconditioned using a preconditioner in accordance with the invention. The formulation contained 53.0% corn, 22.0% poultry meal, 15% soybean meal, and 10% corn gluten meal (all percentages by weight). This formulation was fed into the preconditioner inlet and subjected to treatment therein along with injection of steam and water. The small chamber shaft was rotated at a speed of 900 rpm in the reverse direction, whereas the large chamber shaft was rotated at 50 rpm in the forward direction. Three separate tests were conducted at different feed rates to the preconditioner, and the results of these tests are set forth in Table 1 below. As noted in Table 1, the percent cook values obtained using the preconditioner ranged from 47.6-50.9%, and total SME values varied from 1.97-3.49 kW-Hr/Ton. 
     
       
         
           
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 Name 
                 Test 1 
                 Test 2 
                 Test 3 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 Feed Rate (lbs/hr) 
                 5,000 
                 9,000 
                 10,000 
               
               
                 Cylinder Water (lbs/hr) 
                 850 
                 1,600 
                 1,700 
               
               
                 Cylinder Steam (lbs/hr) 
                 610 
                 1,221 
                 1,306 
               
               
                 Cylinder Oil (lbs/hr) 
                 0 
                 0 
                 0 
               
               
                 DDC Small (L) Shaft Direction 
                 R 
                 R 
                 R 
               
               
                 (F or R) 1   
               
               
                 DDC Small (L) Shaft Speed (RPM) 
                 900 
                 900 
                 900 
               
               
                 DDC Small (L) Shaft Load (%) 
                 51.0% 
                 56.0% 
                 57.0% 
               
               
                 DDC Small (L) HP 
                 15 
                 15 
                 15 
               
               
                 DDC Large (R) Shaft Direction 
                 F 
                 F 
                 F 
               
               
                 (F or R) 
               
               
                 DDC Large (R) Shaft Speed (RPM) 
                 50 
                 50 
                 50 
               
               
                 DDC Large (R) Shaft Load (%) 
                 27.0% 
                 33.0% 
                 31.0% 
               
               
                 DDC Large (R) HP 
                 15 
                 15 
                 15 
               
               
                 Cylinder Weight (lbs) 
                 293 
                 345 
                 350 
               
               
                 Cylinder Retention Time (Minutes) 
                 2.72 
                 1.75 
                 1.61 
               
               
                 Cylinder Downspout Temp (Deg F.) 
                 200 
                 199 
                 200 
               
               
                 DDC Small (L) SME (kW-Hr/Ton) 
                 2.28 
                 1.39 
                 1.28 
               
               
                 DDC Large (R) SME (kW-Hr/Ton) 
                 1.21 
                 0.82 
                 0.69 
               
               
                 Total DDC Calc&#39;d SME 
                 3.49 
                 2.21 
                 1.97 
               
               
                 (kW-Hr/Ton) 
               
               
                 Moisture (MCWB %) 
                 13.01 
                 12.74 
                 14.51 
               
               
                 Total Starch 
                 35.65 
                 34.61 
                 34.7 
               
               
                 Gelatinized Starch 
                 17.28 
                 17.61 
                 16.52 
               
               
                 % Cook 
                 48.5 
                 50.9 
                 47.6 
               
               
                   
               
               
                   1 F refers to the forward direction and R refers to the rearward direction. Directionality is achieved by orientation of the shaft mixing paddles and/or use of oppositely rotating shafts. In the present Examples, the shafts were rotated in the same direction, and in the F direction the paddles are oriented to move the mixture forwardly, whereas in the R direction the paddles are oriented to retard the forward movement of the mixture. 
               
            
           
         
       
     
     EXAMPLE 2 
     In this Example, a standard cat food formulation was prepared and preconditioned as set forth in Example 1. The cat food formulation contained 32% poultry meal, 28% corn, 14% rice, 13% corn gluten meal, 3% beat pulp, 2% phosphoric acid (54% H 3 PO 4 ), and 8% poultry fat (all percentages by weight). In the three separate test runs, the small chamber shaft was rotated at 800 rpm in the reverse direction while the large chamber shaft rotated at 50 rpm in the forward direction. The results of these tests are set forth in Table 2 below, where percent cook varied from 45.8 to 48.1% and total SME values ranged from 2.9 to 3.9 kW-Hr/Ton. 
     
       
         
           
               
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                 Name 
                 Test 4 
                 Test 5 
                 Test 6 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 Feed Rate (lbs/hr) 
                 4,000 
                 4,000 
                 4,000 
               
               
                 Cylinder Water (lbs/hr) 
                 760 
                 760 
                 1,140 
               
               
                 Cylinder Steam (lbs/hr) 
                 580 
                 580 
                 840 
               
               
                 Cylinder Oil (lbs/hr) 
                 200 
                 280 
                 0 
               
               
                 DDC Small (L) Shaft Direction 
                 R 
                 R 
                 R 
               
               
                 (F or R) 
               
               
                 DDC Small (L) Shaft Speed (RPM) 
                 800 
                 800 
                 800 
               
               
                 DDC Small (L) Shaft Load (%) 
                 40.0% 
                 40.0% 
                 42.0% 
               
               
                 DDC Small (L) HP 
                 15 
                 15 
                 15 
               
               
                 DDC Large (R) Shaft Direction 
                 F 
                 F 
                 F 
               
               
                 (F or R) 
               
               
                 DDC Large (R) Shaft Speed (RPM) 
                 50 
                 50 
                 50 
               
               
                 DDC Large (R) Shaft Load (%) 
                 28.0% 
                 29.0% 
                 35.0% 
               
               
                 DDC Large (R) HP 
                 15 
                 15 
                 15 
               
               
                 Cylinder Weight (lbs) 
                 286 
                 288 
                 310 
               
               
                 Cylinder Retention Time (Minutes) 
                 3.21 
                 3.24 
                 2.33 
               
               
                 Cylinder Downspout Temp (Deg F.) 
                 200 
                 200 
                 201 
               
               
                 DDC Small (L) SME (kW-Hr/Ton) 
                 2.10 
                 2.10 
                 1.60 
               
               
                 DDC Large (R) SME (kW-Hr/Ton) 
                 1.70 
                 1.80 
                 1.30 
               
               
                 Total DDC Calc&#39;d SME 
                 3.80 
                 3.90 
                 2.90 
               
               
                 (kW-Hr/Ton) 
               
               
                 Moisture (MCWB %) 
                 9.88 
                 9.75 
                 9.91 
               
               
                 Total Starch 
                 34.61 
                 32.77 
                 33.83 
               
               
                 Gelatinized Starch 
                 15.84 
                 15.78 
                 16.09 
               
               
                 % Cook 
                 45.8 
                 48.1 
                 47.6 
               
               
                   
               
            
           
         
       
     
     EXAMPLE 3 
     In this Example, a floating aquatic feed formulation used in the manufacture of catfish feeds was prepared and preconditioned as set forth in Example 1. The floating aquatic feed formulation contained 20% whole corn, 20% fish meal, 20% de-fatted rice bran, 15% wheat midlings, 10% soybean meal, 10% beat pulp, and 5% wheat (all percentages by weight). The three separate test runs, the small diameter shaft was rotated at 800 rpm in the reverse direction and the large diameter shaft was rotated at 50 rpm in the forward direction. These results are set forth in Table 3 where it can be seen that the cook varied from 78.7-84.5% and the total SME values were 3.7 kW-Hr/Ton. 
     
       
         
           
               
               
               
               
             
               
                 TABLE 3 
               
               
                   
               
               
                 Name 
                 Test 7 
                 Test 8 
                 Test 9 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 Feed Rate (lbs/hr) 
                 4,000 
                 4,000 
                 4,000 
               
               
                 Cylinder Water (lbs/hr) 
                 1,280 
                 1.360 
                 1.520 
               
               
                 Cylinder Steam (lbs/hr) 
                 1,200 
                 1,200 
                 1.200 
               
               
                 Cylinder Oil (lbs/hr) 
                 0 
                 0 
                 0 
               
               
                 DDC Small (L) Shaft Direction 
                 R 
                 R 
                 R 
               
               
                 (F or R) 
               
               
                 DDC Small (L) Shaft Speed (RPM) 
                 800 
                 800 
                 800 
               
               
                 DDC Small (L) Shaft Load (%) 
                 37.0% 
                 37.0% 
                 37.0% 
               
               
                 DDC Small (L) HP 
                 15 
                 15 
                 15 
               
               
                 DDC Large (R) Shaft Direction 
                 F 
                 F 
                 F 
               
               
                 (F or R) 
               
               
                 DDC Large (R) Shaft Speed (RPM) 
                 50 
                 50 
                 50 
               
               
                 DDC Large (R) Shaft Load (%) 
                 29.0% 
                 29.0% 
                 29.0% 
               
               
                 DDC Large (R) HP 
                 15 
                 15 
                 15 
               
               
                 Cylinder Weight (lbs) 
                 284 
                 285 
                 286 
               
               
                 Cylinder Retention Time (Minutes) 
                 2.63 
                 2.61 
                 2.55 
               
               
                 Cylinder Downspout Temp (Deg F.) 
                 204 
                 204 
                 204 
               
               
                 DDC Small (L) SME (kW-Hr/Ton) 
                 2.10 
                 2.10 
                 1.60 
               
               
                 DDC Large (R) SME (kW-Hr/Ton) 
                 1.60 
                 1.60 
                 1.60 
               
               
                 Total DDC Calc&#39;d SME 
                 3.70 
                 3.70 
                 3.70 
               
               
                 (kW-Hr/Ton) 
               
               
                 Moisture (MCWB %) 
                 36.22 
                 35.89 
                 35.28 
               
               
                 Total Starch 
                 27.49 
                 26.87 
                 28.87 
               
               
                 Gelatinized Starch 
                 21.63 
                 22.05 
                 21.86 
               
               
                 % Cook 
                 78.70 
                 82.10 
                 84.50 
               
               
                   
               
            
           
         
       
     
     EXAMPLE 4 
     In this Example, a sinking aquatic feed formulation used in the manufacture of Sea Bass/Sea Breem feeds was prepared and preconditioned as set forth in Example 1. The sinking aquatic feed formulation was made up of 53.5% soybean meal, 15% wheat, 8.5% corn gluten feed, 6.0% corn, 1% sunflower meal, and 16% fish oil. In three separate tests, the small chamber shaft was rotated at 800 rpm in the reverse direction and the large diameter shaft was rotated at 50 rpm in the forward direction. These results are set forth in Table 4, where it will be seen that percent cook ranges from 72.5-75.8% and total SME values were from 2.2-3.2 kW-Hr/Ton. 
     
       
         
           
               
               
               
               
             
               
                 TABLE 4 
               
               
                   
               
               
                 Name 
                 Test 10 
                 Test 11 
                 Test 12 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 Feed Rate (lbs/hr) 
                 5,000 
                 7,000 
                 9,000 
               
               
                 Cylinder Water (lbs/hr) 
                 940 
                 1,330 
                 1,710 
               
               
                 Cylinder Steam (lbs/hr) 
                 716 
                 940 
                 1,330 
               
               
                 Cylinder Oil (lbs/hr) 
                 350 
                 490 
                 270 
               
               
                 DDC Small (L) Shaft Direction 
                 R 
                 R 
                 R 
               
               
                 (F or R) 
               
               
                 DDC Small (L) Shaft Speed (RPM) 
                 800 
                 800 
                 800 
               
               
                 DDC Small (L) Shaft Load (%) 
                 45.0% 
                 49.0% 
                 54.0% 
               
               
                 DDC Small (L) HP 
                 15 
                 15 
                 15 
               
               
                 DDC Large (R) Shaft Direction 
                 F 
                 F 
                 F 
               
               
                 (F or R) 
               
               
                 DDC Large (R) Shaft Speed (RPM) 
                 50 
                 50 
                 50 
               
               
                 DDC Large (R) Shaft Load (%) 
                 31.0% 
                 36.0% 
                 39.0% 
               
               
                 DDC Large (R) HP 
                 15 
                 15 
                 15 
               
               
                 Cylinder Weight (lbs) 
                 306 
                 334 
                 357 
               
               
                 Cylinder Retention Time (Minutes) 
                 2.62 
                 2.05 
                 1.74 
               
               
                 Cylinder Downspout Temp (Deg F.) 
                 201 
                 199 
                 199 
               
               
                 DDC Small (L) SME (kW-Hr/Ton) 
                 1.90 
                 1.60 
                 1.30 
               
               
                 DDC Large (R) SME (kW-Hr/Ton) 
                 1.30 
                 1.10 
                 0.90 
               
               
                 Total DDC Calc&#39;d SME 
                 3.20 
                 2.70 
                 2.20 
               
               
                 (kW-Hr/Ton) 
               
               
                 Moisture (MCWB %) 
                 11.32 
                 12.72 
                 13.14 
               
               
                 Total Starch 
                 11.74 
                 12.05 
                 12.52 
               
               
                 Gelatinized Starch 
                 8.63 
                 9.14 
                 9.08 
               
               
                 % Cook 
                 73.50 
                 75.80 
                 72.50