Rotary Reactor for Nixtamalization

Abstract

The invention relates to the dough and pancake industry, and all new industries wherein a product undergoes nixtamilization. The invention more particularly relates to a rotary reactor for nixtamalization, having a better capacity for homogenization of the reagents in both the process and product. The advantages of reactors included in the invention when compared to prior art is that they enable a higher degree of homogenization of the trinomial water, lime and product to be nixtamalized and make it possible to control the homogenization operation of the trinomial without damaging the soft grains and to achieve homogenization of the temperature throughout the entire mass of the product. Structurally speaking, the reactors according to the present invention are characterized in that they are made up of a center chamber surrounded by a series of jackets, including one longitudinal end at a given height, and another longitudinal opposite end at a lower height, wherein the longitudinal line of the reactor forms an angle which is selected between 15° and 30° in relation to the horizontal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic longitudinal section of the reactor which is the object of the present invention, showing the angle of inclination of said reactor in relation to the horizontal.

FIG. 2 shows a cross section of the reactor with the bands which drag the material, affixed at a 90 degree angle.

FIG. 3 shows a schematic cross section of the reactor illustrated in FIG. 2 with the bands affixed in an inclined position.

FIG. 4 shows the scheme of the electrical connection from the motor which moves the reactor, to the frequency variator.

FIG. 5 shows the details of the hatch for emptying in the embodiment which consists of heating volutes.

FIG. 6 shows in conventional perspective the reactor in the embodiment which consists of heating volutes.

FIG. 7 shows in conventional perspective the reactor of the present invention in the embodiment in which cooling volutes are also included.

FIG. 8 shows a cross section of the reactor showing the dragging bands in the embodiment in which they are straight.

FIG. 9 shows a cross section of the reactor in which gull wing dragging bands have been installed.

FIG. 10 shows the minimum changes required in the state of the art rotary reactor for use with one sole working fluid.

In order to better understand the invention, a detailed description shall be made of some of the embodiments of the later shown in the drawings annexed to the present description with illustrative but not limiting means.

DETAILED DESCRIPTION OF THE INVENTION

The details which are characteristics of the reactor are the teachings of the present invention and are clearly shown in the following description and in the illustrative drawings which are annexed, the same reference signs showing the same parts.

With reference to FIG. I which shows a schematic longitudinal section of the reactor which is the object of the present invention, marking angle α of an inclination of said reactor in relation to the horizontal, we shall indicate that this angle varies between 15 and 30°.

If this inclination is less than the smallest extreme of this interval, the emptying of the nixtamalized material is very difficult, a remnant of the material always remaining in the reactor.

With an inclination greater than 30° the capacity of the reactor, which is open to air, is reduced to avoid material from spilling since the reactor is open on the ends.

FIG. 2 shows a cross section of the reactor with the bands which drag the material, affixed at an angle of 90 degrees. The height h of the band is variable and depends on the amount of material which is to be dragged.

The larger the amount of material to be dragged, more vigorous is the agitation and the reaction is better, however if the product to be nixtamalized is soft, this agitation may spoil it, making the dough difficult to handle, due to gelatinized starch.

It was proved that a height of the band between 20 and 30 centimeters allowed for handling a variety of types of corn, controlling the speed of rotation of the reactor.

FIG. 3 shows a schematic cross section of the reactor illustrated in FIG. 2 with the bands affixed on an incline. Inclination β of the band in relation to the internal face of the reactor allows for determining the height at which the product will fall from the rotation. The more acute the angle on the rotating side, the higher the material is transported before falling again.

With a more obtuse angle on the rotating side the grain begins to slide more quickly, and when this dragger reaches a little over one fourth of a turn, the entire product has already slid down completely.

It was proven that the appropriate inclination of the dragging bands 2 was between 80 and 100°. Optimally for most types of corn, the angle is 90°.

FIG. 4 shows the scheme of the electrical connection of the motor 40 which moves reactor 1 to the frequency variator 41.

With this frequency variator the speed control of the rotation of the reactor is obtained, making the agitation more or less vigorous, depending on the conditions required for the type of material.

FIG. 5 shows the detail of the hatch for the controlled emptying of the nixtamalized material. This hatch is located in the lower longitudinal end of the reactor, at its lowest end.

It consists of a panel with affixing means to be sealed to the periphery of a window of the reactor. These means are designed to allow for regulating the distance between the panel and the external wall of the reactor. By means of this control the amount of already nixtamalized material can be controlled as it passes to the other steps in the process. The farther the panel is separated from the outer wall of the reactor, the more material will pass through in each step of rotation in which the exit is in the lower position.

In this embodiment, the seal and control of separation between the panel and the reactor is achieved by means of a pair of threaded dowels and corresponding butterfly nuts or nuts with flywheels, which when turned one way close and seal and when turned the other way separate the panel to a degree, attaining variable openings.

Since the completely nixtamalized material is material in which all the water and lime have been absorbed, at the time it is unloaded there is no problem of dripping. The material simply slides due to the effect of gravity through the corresponding opening between the panel of emptying control which is the same panel which also seals during the nixtamalization process.

The operation of the reactor then consists of receiving the amount of material to be nixtamalized together with water and lime. Depending on the moisture content and hardness of the corn are the amount of water and lime to be added. Also using these variables, the time, temperature and rotation speed are determined. Said speed is controlled by means of the frequency variator of the motor of the rotating reactor. When the nixtamalization time is over the exit of the reactor opens, the panel which controls this exit is pulled open and in each interval of the rotation when the opening is lower than or at the level of the upper level of the nixtamalized material a certain amount of the material falls out, these dumpings being repeated until the reactor is completely empty.

With reference to FIG. 6, this shows a conventional perspective of the reactor in the embodiment consisting of heating volutes. In this figure the external covering which makes up the continuous form jacket has been omitted.

The body of reactor 61 consists on its exterior face of a volute 62 which on the inside will conduct the working fluid. The working fluid will enter through the end of volute 63 and will exit through the opposite end 64.

Besides attaining the circulation of air with longer lodging time, at the same time displacement which allows for a better transfer of sensitive heat contained in the working fluid (referring to burnt gases and thermal oil) and transfer of latent heat and sensitive heat in the case of vapor are obtained.

The later is true due to the fact that the regime of fluid flow is a turbulent flow which diminishes the phenomena of external layer in connection with the interior surface of the ducts.

Furthermore, it was determined that although any type of burner could achieve comparative advantages in relation to state of the arte reactors, the most recommendable burners are low pressure modulating burners.

We have, then, in one of the embodiments, a burner which provides sensible heat in order to reach the required temperatures, during a predetermined time, at the entrance of the volutes, generally in the lower part of the reactor.

In the case that water vapor is used as the working fluid, this is generally fid in through the top part, the transmission coefficient for heat being much higher than in the case of burnt gases.

In the case that hot gases are used, two possibilities exist; the first is that of heating the oil in a Dow Ther and later having it circulate through the volute. By controlling the mass flow and the temperature of the thermal oil it is possible to control the temperature of the nixtamalized corn for a precise nixtamalization process.

The other possibility consists of heating the thermal oil by means of electric resistances, allowing temperature control by electromechanical means.

In order to achieve the cooling of the reactor at the end of the nixtamalization process and reach the resting temperature, an adaptation is made to the reactor as can be seen in FIG. 7, where in a conventional perspective the reactor of the present invention in an embodiment in which cooling volutes are included is illustrated.

Thus, in this embodiment, the hot working fluid will be fed in by means of one of the volutes and cold water will be introduced through the other volute, without adding hot gases through the heating volute, when it is necessary to reduce the temperature within the nixtamalization reactor.

In the embodiment of reactor illustrated in FIG. 6 it is possible to achieve cooling by reducing or completely putting out the flame of the burner and by means of some mechanism introducing room temperature air through the only volute.

Although not illustrated, it was determined as a result of various tests, that it is possible to use a reactor with the characteristics of the state of the art with two jackets, making some window-like perforations in the common wall of the outer jacket in order to achieve the circulation of working fluid in the interior of the interior jacket. The working fluid would enter the external chamber and through the windows made in the common wall.

In relation to another aspect of the present invention, FIG. 8 shows a cross section of the reactor showing the dragging bands in the embodiment in which said bands are straight. The height (h) of the band is between 1 and 40 cm, and the number of said bands (n) is between 1 and 12.

FIG. 9 shows a cross section of a reactor in which gull wing dragging bands have been installed. In these bands there is a first cant p1 and a second cant p2, the second cant being ⅓ of the height of the whole band.

FIG. 10 shows the minimal changes required for the state of the art rotary reactor to be used with one single working fluid.

These modifications consist simply of making some windows V in the common wall of the external jacket and the internal jacket.

The invention has been sufficiently described so that any person with average knowledge in the field may reproduce and obtain the results we mention in the present invention. However, any person, capable in the field of the technique of the present invention is able to make modifications not described in the present application, however, if for the application of these modifications in the determined structure or in the manufacturing process of the later, the material laid claim to in the following claims is required, said structures should be considered within the scope of the invention.

Claims

1. Rotary reactor for nixtamalization, of the type formed by a central chamber and a series of jackets surrounding it, characterized by consisting of a longitudinal end at a given height, and another longitudinal opposite end at a lower height, wherein the longitudinal line of the reactor forms an angle which is selected between 15° and 30° in relation to the horizontal.

2. Rotary reactor for nixtamalization as claimed in claim 1, characterized by consisting of inside the central chamber, affixed to the internal face, a series of draggers that consist of parallel bands, placed tangentially to the interior face of the central chamber of the reactor.

3. Rotary reactor for nixtamalization as claimed in claim 2, characterized by the band forming an angle in relation to the internal face of the central chamber, which is selected from between 80 and 100°.

4. Rotary reactor for nixtamalization as claimed in claim 3, characterized by the band forming an angle in relation to the internal face of the central chamber, which is equal to 90°.

5. Rotary reactor for nixtamalization as claimed in claim 2, characterized by la band having height selected between the interval formed between 20 and 30 cm.

6. Rotary reactor for nixtamalization as claimed in claim 5, characterized by the band having a height of 25 cm.

7. Rotary reactor for nixtamalization as claimed in claim 1, characterized by the reactor consisting of a means of control for the exit of nixtamalized material, which consists of an opening in the longitudinal end of the reactor which is at the lower height in relation to the height of the opposite end, a panel of larger perimeter than the opening, but with a geometric configuration which may occlude said opening, and some affixing means for this reactor panel, corresponding to the position of the opening, said affixing means having the ability to control the degree of separation between the panel and the reactor in order to allow the exiting of more or less nixtamalized material.

8. Rotary reactor for nixtamalization as claimed in claim 7, characterized by said affixing means being formed by a pair of threaded dowels located on the opposite ends of the panel and some bodies with internal threads for screwing said dowels, displacing said panel towards the reactor or separating it from the reactor.

9. Rotary reactor for nixtamalization as claimed in claim 1, characterized by said affixing means being formed by a pair of threaded dowels placed on opposite ends and some bodies with internal threads for screwing said dowels, displacing said panel towards the reactor or separating it from the reactor.

10. Rotary reactor for nixtamalization, the reactor characterized by on the internal face of the wall which divides the central chamber from the intermediate chamber, dragging bands are placed, in number between 1 and 12, with a height of band between 1 and 40 cm.

11. Rotary reactor for nixtamalization as described in claim 10, characterized by said bands presenting la configuration of a gull wing.

12. Rotary reactor for nixtamalization as described in claim 10, characterized by having just one jacket wherein working fluid is fed for heating the nixtamalization chamber; the working fluid is chosen between vapor, burnt gases and thermal oil and the source of heat is chosen between the burning of a fuel and the passage of electric energy through resistances.

13. Rotary reactor for nixtamalization as described in claim 12, characterized by the working fluid being burnt gas.

14. Rotary reactor for nixtamalization as described in claim 10, characterized by consisting of an external volute formed by a band which is united by means of a helicoidal cant to the external surface of the nixtamalization chamber, in order to allow a longer flow of the working fluid thus obtaining better thermal exchange.

15. Rotary reactor for nixtamalization as described in claim 14, characterized by besides a front volute, there is a second intermediate volute with the same development as the first; said second volute is formed in order to allow the passage of a second working fluid, at a low temperature in relation to the first working fluid.

16. Rotary reactor for nixtamalization as described in claim 15, characterized by also said second volute being formed by a half round which is attached to the intermediate space of the first volute and follows the same rotation.

17. Rotary reactor for nixtamalization as described in claim 10, characterized by consisting of two jackets communicated by means of a series of windows made in the common wall of said jackets.

18. Rotary reactor for nixtamalization as claimed in claim 3, characterized by la band having height selected between the interval formed between 20 and 30 cm.

19. Rotary reactor for nixtamalization as claimed in claim 4, characterized by la band having height selected between the interval formed between 20 and 30 cm.

20. Rotary reactor for nixtamalization as claimed in claim 2, characterized by the reactor consisting of a means of control for the exit of nixtamalized material, which consists of an opening in the longitudinal end of the reactor which is at the lower height in relation to the height of the opposite end, a panel of larger perimeter than the opening, but with a geometric configuration which may occlude said opening, and some affixing means for this reactor panel, corresponding to the position of the opening, said affixing means having the ability to control the degree of separation between the panel and the reactor in order to allow the exiting of more or less nixtamalized material.