Continuous Intermeshing Agitator Food Cooker

Abstract

A method and apparatus for continuous cooking of a pumpable food product including a process chamber 20 having an inlet end 22 and an inlet port 24 for introducing food product 12 into the chamber, an outlet end 26 and an outlet port 28 for the discharge of the cooked food product 14, and a central portion between the two ends with a plurality of steam inlets 32 arrayed along the walls of the central portion; inside the chamber at least two non-conveying agitator 80 with arms 86 depending for mixing and kneading food product; a drive means 90 for the agitators; a loading device 102 to feed a pump 100 that introduces food to the cooking chamber and provides the motivation to discharge the cooked food product through the outlet; and a controller 110 that monitors and controls the inlet pump, the steam inlet valves and the agitator speed and direction which all impact the quality characteristics of the cooked food product.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:

FIG. 1A is a front elevational view of the preferred embodiment of this invention;

FIG. 1B is a left side elevational view of FIG. 1A where the food product inlet is located;

FIG. 1C is a right side elevational view of FIG. 1A where the cooked product outlet is located;

FIG. 1D is a top plan view of FIG. 1A;

FIG. 2 is an enlarged cross-sectional view taken along lines 2-2 in FIG. 1A and FIG. 1D;

FIG. 3 is an enlarged cross-sectional view of a poppet valve in the area denoted by a dashed line 3-3 in FIG. 2;

FIG. 3A is a plan view of the top of the poppet valve shown in FIG. 3;

FIG. 4 is a top plan view of two agitators used in the preferred embodiment;

FIG. 4A is a end view of FIG. 4;

FIG. 5 is an enlarged cross-sectional view of an agitator taken along line 5 -5 in FIG. 4, showing the shape of an agitator arm;

FIG. 6 is an enlarged cross-sectional view of an agitator similar to FIG. 5 showing an alternate shape of an agitator arm;

FIG. 7 is an elevational view of an alternate embodiment of an agitator with additional arms added to increase mixing at low RPM;

FIGS. 7A-7I are cross-sectional views of agitator arms taken along lines indicated in FIG. 7;

FIG. 8A is a front elevational view of an alternate form of the preferred embodiment of this invention wherein the process chamber is segmented to allow the size of the cooker to be enlarged or reduced;

FIG. 8B is a top plan view of FIG. 8A;

FIG. 9 is a top plan view of an alternate form of a pair of agitators wherein the shafts are segmented to allow the size of the cooker to be lengthened or shortened;

FIG. 10 is a schematic diagram of the system of the preferred embodiment of this invention;

FIG. 11 is a flow chart of the steps in implementing the method of this invention; and

FIG. 12 shows another preferred embodiment of the agitators and agitator arms of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1-5, the present invention is generally denoted as 10. The cooking chamber 20 has an inlet side 22 with an inlet 24 and an outlet side 26 with an outlet 28. The central section 30 of the chamber between the ends has a plurality of steam inlets 32 arrayed along the chamber walls 34. Each steam inlet has a input valve 40 attached to the chamber wall and fed steam 42 via a line 42 from a control valve 46 attached to a manifold 48. The control valve 46 also has a vacuum breaker on the line 42 side to sense and compensate for a vacuum that may be caused in the poppet valve when closed. As steam cools and condenses it could suck food product into the valve.

The poppet valve 40 has a valve body 50 that has an inlet 52 where steam 42 is delivered via line 44. The stainless steel poppet valve and housing are coated with a food release coating or may be made of high temperature plastic which will not transmit heat to the surrounding area which could cause product burn-on. This would also eliminate the need for cooling that portion of the cooker. The steam enters the main chamber 54 of the poppet valve which communicates with the valve head 60 via ports 58. The valve head in the preferred embodiment is flat and round with a tapered face that mates and seats perfectly into a round hole 68 with a chamfered edge 69. The same sort of valve closure is common on the intake and exhaust valves in gas engines. The valve is normally closed by a spring 62 located at the base 64 of the valve stem 66. When the pressure of the steam inside the main body of the poppet valve exceeds the retaining force of the spring, the valve stem will move thus allowing steam to enter the cooking chamber 30. The valve opening is designed to allow steam to flare out initially in a conical shape whose vertex is indicated at V (in FIG. 3) and whose base plane would be normal to axis “A” indicated in FIGS. 3 and 3A. This arrangement prevents food product from entering the poppet valve body as the steam pressure is greater than the pressure inside the cooking chamber.

The base 70 of the valve 40 is held against the valve body and seal 72 by a ring clamp 74 which is easily accessed and removed by loosening wing nut 76. This design facilitates quick disassembly, inspection and maintenance.

At least two agitators 80 are required in the preferred embodiment of the present invention. The distal ends 82 are rotatably mounted to the inlet side 22 of the cooking chamber 20. The proximal ends 84 go through the outlet end 26 and are coupled and synchronized at gear box 94 which is connected to a transmission 92 that is driven by motor 90.

Depending at regular spaced intervals from the agitators 80 are agitator arms 86. The preferred embodiment can be seen in FIG. 5 where the arms 86 are round in cross-sectional shape and impart very little spear to the food product. An alternate arm cross-sectional shape is shown in FIG. 6 where the arm 87 has a tear drop shape profile. The sharp edge 89 will impart significant shear to the food product when the agitator is rotated in the direction where the sharp edge 89 is leading.

Since the agitators are non-conveying, their rotation is independent of the product flow and strictly used for mixing and kneading the product. This is a tremendous advantage because low RPM agitators impart very little shear to the food product.

The product is conveyed in and through the cooking chamber 20 by a positive displacement type pump 100 (FIG. 10) near the cooking chamber inlet 22. A hopper 102, auger or another pump can be used to feed the displacement pump to insure that the pump is consistently supplied with food product.

The process variables that effect the cooked food quality are regulated by a controller 110 as shown in the schematic diagram (FIG. 10). There may be monitoring points such as temperature sensors and/or steam pressure sensors 112 on the inlet 22 and outlet 28 to register the cooked food temperature and pressure of the product.

The process variables are identified in a flow chart (FIG. 11) describing the method of the present invention. The variables are listed in step 124 and are: (a) pumping rate; (b) quantity, temperature and location of hot steam introduced to the cooking chamber; and (c) the RPM and direction of the agitation.

In step 126 temperatures and pressure of incoming food, steam and outgoing cooked food are monitored.

In step 128 the cooked food product is assessed. Depending on the assessment will determine the feedback 129 to make changes to the variable parameters in step 124. The particular food product being cooked will determine the variable settings.

EXAMPLE 1—Mozzarella Cheese Production

A typical target for pH of mozzarella cheese curd being fed into the mozzarella cooker would be 5.08 at a temperature of 80 degrees F. With a production rate of 5000 lbs per hour a typical inlet steam supply pressure would be 120 PSI, the injectors would be set to open in sequence starting with the first injector at the inlet of the cooker and to open as necessary to reach the set point temperature setting with a temperature setting of the outgoing, heated mozzarella cheese set at 140 degrees F. Ideally the agitator RPM would be set at 100 RPM. With the dual intermeshing agitator cooker one would expect these settings to produce excellent mozzarella cheese. If the pH of the cheese curd was 5.20 the set point temperature of the cooker would be raised to 145 degrees F. to compensate for the increased pH and minimize the loss of cheese moisture and milk solids. If the cheese came out of the cooker with evidence of small, unmelted cheese curd lumps the RPM speed of the agitators should be increased 5 RPM at a time until the evidence of the unmelted cheese curd disappeared. If the heated cheese had evidence of moisture and milk solids separation, the temperature setting of the cooker should be raised 1 degree F. at a time until the moisture separation disappeared. The steam pressure differential between the steam source and the product pressure inside of the cooking chamber must be maintained high enough to counteract the steam poppet spring to create a stable flow of steam through the injectors into the product cooking chamber.

EXAMPLE 2—Beef Taco Meat Production

In the case of the cooking of ground beef taco meat, the incoming raw meat temperature would be approximately 35 degrees F. At a production rate of 5000 lbs per hour the cooked meat temperature set point would be set at 155 degrees F. and the agitator RPMs set at 250. The steam injector set up recommended is to spread out the heat input the length of the cooking column with the sequence of the opening of the injectors spaced out, opening every third injector until the temperature set point is reached. If the particle size of the cooked ground beef coming out of the cooker is too small the agitator RPM should be reduced 25 RPM at a time until the particle size is correct. If there are uncooked lumps of meat coming out of the cooking chamber the temperature set point should be increased by a few degrees or the agitator RPM increased by 25 RPM. If both the particle size is too small and the meat has uncooked lumps, location of the open steam injectors need to be moved closer to the inlet of the cooking chamber to allow for the heated meat to be exposed to the agitation in the cooking chamber for a longer period by adding the heat energy earlier in the process.

An alternate embodiment of an agitator is shown in FIG. 7. This agitator 130 has more arms 132 than agitator 80 which would increase the mixing rate while at the same RPM. The shaft 134 is larger and hollow.

Another alternate embodiment of the agitator is shown in FIG. 9. This agitator 140 is segmented with the shaft having a distal end section 142 and a proximal end section 144. The center section can have one or more modules sections 146 added to lengthen the agitator. The shaft shown in FIG. 9 has four modules added. They are joined and pinned by complimentary male and female fittings integral to the ends of the modular sections.

Agitators 140 are designed to be used with an alternate cooking chamber embodiment shown in FIGS. 8A and 8B. Cooking chamber 160 and steam manifold 170 are segmented so the size of the apparatus can be modified for greater or smaller throughput. Cooking chamber 160 has an inlet side 162 and an outlet side 164. In between are modular sections 166 that can extend or shorten the length of the cooker. They are removably fastened together at joints 168 and have steam inlets in their walls. In a similar manner a steam manifold 170 is in sections to allow lengthening or shortening by adding or subtracting modules 172 and are fastened together at joints 174.

FIG. 12 shows yet another alternative embodiment 200 of the agitator arms of the present invention, in this instance comprising a radial spoke configuration. The intermeshing aspect of the invention is obviated by this configuration, inasmuch as simple linear spacing of the arms 202 along the length of the agitator shafts will suffice to prevent interference of the agitator elements. In this embodiment, as with the prior embodiments, the agitator arms can be shaped in either a cylindrical or tear-drop shape. Sufficient kneading, pulling, and stretching of the developing pasta filata cheese.

The foregoing description and illustrations should not be construed as limiting the scope of the invention, which is defined by the appended claims.

Claims

1. A continuous food cooking apparatus comprising: a process chamber having a top side and a bottom side and at least one interior wall, and with a product inlet at one end and a cooked product outlet at the opposite end;product conveying means disposed prior to and exterior to said product inlet of said process chamber;a plurality of steam inlet ports disposed on said at least one interior wall of said process chamber between said product inlet and said product outlet;a plurality of non-conveying agitators located within said process chamber communicating and driven by a means exterior to said process chamber.

2. The apparatus of claim 1 wherein said product outlet is located on said top side of said process chamber.

3. The apparatus of claim 1 wherein said product inlet is located on said bottom side of said process chamber.

4. The apparatus of claim 1 wherein said product conveying means comprises at least one positive displacement pump.

5. The apparatus of claim 1, wherein said product conveying means comprises a combination of at least one screw auger and at least one positive displacement pump.

6. The apparatus of claim 1, wherein said steam inlet ports are normally closed poppet valves.

7. The apparatus of claim 6, wherein each of said poppet valves, when opened, release steam in a substantially tangential trajectory to the plane of said at least one interior wall of said process chamber proximate the location said steam inlet port is located.

8. The apparatus of claim 6, wherein each of said poppet valves, when opened, releases steam radially in a plane normal to the axis of said inlet port.

9. The apparatus of claim 6, wherein each of said poppet valves, when opened, releases steam radially in a conical flare having a vertex proximate said steam inlet port and a base extending said process chamber.

10. The apparatus of claim 1, wherein said steam inlet ports are discretely controlled relative to temperature of steam.

11. The apparatus of claim 1, wherein said steam inlet ports are discretely controlled relative to opening and closing duration time.

12. The apparatus of claim 1, wherein said steam inlet ports are discretely controlled relative to temperature of steam and opening and closing duration time.

13. The apparatus of claim 1, wherein said agitators have radially depending, non-intersecting, arms.

14. The apparatus of claim 1, wherein said agitators have radially depending, overlapping, intermeshing, non-intersecting, arms.

15. The apparatus of claim 1, wherein said agitators have radically depending, intermeshing, arms shaped such that when rotated in one direction they impart minimal shear to the product, and when rotated in the opposite direction impart high shear to the product.

16. The apparatus of claim 1, wherein said process chamber and agitators are composed of modular segments.

17. The apparatus of claim 1, further including inlet feed pumps disposed at said inlet port, and a control system, wherein said inlet feed pumps at said inlet port, said steam inlet ports, and said agitators are independently controlled and collectively considered to affect the resulting cooked product at said outlet of said apparatus.

18. A method for the continuous cooking of food product in a cooking chamber utilizing steam, feed pump(s), and non-conveying agitators, wherein, the food product is cooked by the introduction of steam, the surface of the product being constantly modified by non-conveying agitators, and wherein the speed and direction of the non-conveying agitators determines the outcome and quality of the cooked product.

19. The method of claim 18, further including the step of controlling the outcome and characteristics of the cooked food product using the locations and temperature of steam disbursement within the cooking chamber.

20. A method for the continuous cooking of food in a cooking chamber in claim 18 where in the speed and direction of the non-conveying agitators and the locations and temperature of steam disbursement determines the outcome and quality of the cooked product.

21. A method for the continuous cooking of food in a cooking chamber utilizing steam, pump(s) and non-conveying agitators, wherein the product is cooked by the introduction of steam that is bathed over the surface of the product, the surface of the product being constantly modified by non-conveying agitators, and where in the speed and direction of the non-conveying agitators, the locations and temperature of steam disbursement determines the outcome and quality of the cooked product.