GRAIN PUFFING APPARATUS

Technical Field The present invention relates to a grain puffing apparatus which puffs grains such as uncleaned rices, rices, corns, and beans in an extrusion method without a special heating apparatus, and more particularly to a grain puffing apparatus which efficiently discharges heat generated in the inside of the grain puffing apparatus and enables puffing of grains without stopping of operation due to excessive heating of the grain puffing apparatus.

Background Art

A grain puffing apparatus stands for an apparatus which inputs grains such as uncleaned rices, rices, corns, and beans through an inlet of a vessel having a closed space together with air while heightening the inner pressure of the vessel and then opens the outlet of the vessel all at once to then be expanded. A conventional grain puffing apparatus has a structure of heating and cooking grains which have been input into a closed space, heightening the inner pressure of the closed space by vapor exhausted from the cooked grains, and extruding and puffing the grains to the outside at the state where the inner pressure of the closed space has been heightened.

In the case of the conventional grain puffing apparatus, when grains are processed at the state where the grains are heated at about 280 °C or so. Since there is a problem that the nutrient of grains is destroyed if the grains are heated at 150 ^° C or more, it is not so appropriate to use the conventional grain

^■ puffing apparatus as an apparatus for making foods good for health.

In addition, there is a problem that an energy efficiency drops because the conventional grain puffing apparatus should be heated by a special heating source. Further, there is a problem that the conventional grain puffing apparatus is complicated due to the special heating source. Further, since a degree of heating grains differs at the respective steps in the process of processing the grains, there is a problem that a separate circuit for controlling the temperature of the conventional grain puffing apparatus should be essentially added.

Disclosure of the Invention

To solve the above problems, it is an object of the present invention to provide a grain puffing apparatus which can enable puffing of grains without using a heating source, and efficiently discharge heat which is generated during puffing, to thereby prevent vapor from flowing backward and enable a continuous operation of the grain puffing apparatus.

To accomplish the above objects of the present invention, according to an aspect of the present invention, there is provided a grain puffing apparatus comprising: a motor; a screw whose one end is coupled to the motor, and thus which transfers and compresses grain while rotating; a first screw spiral formed on the outer circumferential surface of the screw in a certain direction; a second screw spiral which is formed from the central portion of a first pitch of the first screw spiral on the outer circumferential surface of the screw

and in the same direction as that of the first screw spiral; at least one thread hitch that is formed on the other end of the screw and that connects threads forming the first screw spiral and the second screw spiral; a screw groove that is formed on the other end of the screw, and is formed along the circumferential direction of the screw; a cylinder that surrounds the outer circumferential surface of the screw and compresses grain with the screw, and thus which heats the grain by the compression and changes the grain into a gel state; first and second cylinder spirals which are formed on the inner circumferential surface of the cylinder, in correspondence to the first screw spiral and the second screw spiral, respectively; a grain inlet unit formed at the end of the motor of the cylinder; and a puffing unit which rapidly gushes grains that are changed into the gel state by the screw and the cylinder so as to be puffed, wherein the puffing unit comprises: a main body which comprises a first space portion accommodating the other end of the screw and a second space portion accommodating the other end of the cylinder and part of the screw, and whose one side is opened; a cover which closes the opened one side of the main body and in which a grain outlet is formed; and a clamp which fixes the cover and the main body.

Preferably but not necessarily, the inner diameter of the cylinder becomes smaller from the motor to the puffing unit. Preferably but not necessarily, the minimum inner diameter of the

portion where the threads on the inner circumferential surface of the cylinder are formed is larger than the outer diameter of the thread portion of the screw.

Preferably but not necessarily, the grain puffing apparatus further comprises a cutter which cuts grain which is discharged through the grain outlet of the cover into a certain length, and which rotates at a constant speed at the outer portion of the cover.

Brief Description of the Drawings

The above and other objects and advantages of the present invention will become more apparent by describing the preferred embodiments thereof in detail with reference to the accompanying drawings in which:

FIG. 1 is a schematic diagram for explaining a grain puffing apparatus according to an embodiment of the present invention;

FIG. 2 is an explosive perspective view of a motor, a screw, a cylinder, a puffing unit which are illustrated in FIG. 1; and

FIG. 3 is a cross-sectional view of FIG. 2.

Best Mode for Carrying out the Invention

The above and/or other objects and/or advantages of the present invention will become more apparent by the following description.

Hereinbelow, a grain puffing apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawing.

As shown in FIG. 1, a grain puffing apparatus according to an embodiment of the present invention includes a motor 10, a screw 20, a cylinder 30, a puffing unit 40, and a cutter 50.

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The motor 10 rotates the screw 20.

As the screw 20 rotates according to rotation of the motor 10, grains gl are transferred and compressed. In FIG. 1, a reference alphanumeric designation gl stand for grains which should be puffed or in the process of puffing, and a reference alphanumeric designation g2 stands for grains in which puffing has been ended.

A first screw spiral 21 and a second screw spiral 22 are formed on the outer circumferential surface of the screw 20 in a certain direction, respectively. The second screw spiral 22 is started and spirally formed from the central portion of the first pitch of the first screw spiral 21, and is formed in the same pitch as the pitch of the first screw spiral 21. Therefore, the pitch -, between the first screw spiral 21 and the second screw spiral 22 becomes half . the pitch of the first screw spiral 21. The screw 20 has a double spiral structure of the first screw spiral 21 and the second screw spiral 22. The reason why the screw 20 has a double spiral structure is to intercept heat which is generated when grains gl are transferred from one end of the screw 20 to the other end thereof from flowing backward, that is, toward the one end of the screw 20 from the other end thereof. At least one thread hitch 23 that connects threads forming the first screw spiral 21 and the second screw spiral 22 is formed on the other end of the screw 20. As illustrated in FIG. 2, a pair of the thread hitches 23 are provided, and form an angle of about 180°to face each other on the outer circumferential surface of the screw 20. A compression degree of the grains gl increases at the other end of the screw 20 and frictional heat due to friction between the

grains gl and the respective inner surfaces of the screw 20, the cylinder 30, and the puffing unit 40 further increases. Preferably, it is required that the grains gl be compressed at a state where the grains gl are made into a gel state. A thermal conductivity increases at the other end of the screw 20 by the thread hitches 23. Accordingly, the heating value or calorific value in the puffing unit 40 becomes much larger, to thereby provide an advantage of maintaining the optimum puffing temperature of the grains gl.

A screw groove 24 is formed along the circumference of the screw spiral, at the other end of the screw 20, that is, at the side of the thread hitch 23. The screw groove 24 may be formed on the thread portions of the first screw spiral 21 and the second screw spiral 22 and the thread hitch 23 between the first screw spiral 21 and the second screw spiral 22. The outer diameter of the screw groove 24 is preferably formed a , little smaller than the outer, diameter of the screw vale portion of the screw 20. The cylinder 30 compresses the grains gl that is transferred by the screw 20 in a form of surrounding the outer circumferential surface of the screw 20, and makes the grains gl self-generate heat by themselves and changes the grains gl in a gel state by the compression action.

A first cylinder spiral 31 and a second cylinder spiral 32 are formed on the inner circumferential surface of the cylinder 30, in correspondence to the first screw spiral 21 and the second screw spiral 22, respectively.

The pitch of the first screw spiral 21 equals the pitch of the first cylinder spiral 31, and the pitch of the second screw spiral 22 equals the pitch of the second cylinder spiral 32. A grain inlet 33 is formed at one end of the cylinder 30, that is, at the end

of the motor 10. Accordingly, grains gl are input into a space that is formed by the screw 20 and the cylinder 30 through the grain inlet 33.

The inner diameter of the cylinder 30 becomes smaller as it goes from the motor 10 to the puffing unit 40. Accordingly, distances dl, d2, d3, and d4 between the screw spirals 21 and 22 and the cylinder spirals 31 and 32 become gradually smaller. This is, dl is bigger than d2, d2 is bigger than d3, and d3 is bigger than d4.

Here, the minimum inner diameter of the portion where the threads on the inner circumferential surface of the cylinder 30 are formed is larger than the outer diameter of the thread portion of the screw 20.

The puffing unit 40 includes a main body 41, a cover 42 and a clamp 43.

A first space portion 411 accommodating the other end of the screw 20 .. and a second space portion 412 accommodating the other end of the cylinder 30 r and part of the screw 20 are formed in the main body 41. The other end of the motor 10 is opened.

The cover 42 closes the opened portion of the main body 41. A grain outlet 421 through which puffed grains are discharged is formed on the cover 42.

The clamp 43 has a structure of clamping the main body 41 and the cover 42, and can be deformed to a degree by heat and pressure that are generated from the inside of the puffing unit 40.

The cutter 50 cuts grains g2 which are discharged through the grain outlet 421 of the cover 42 after puffing has been ended. The cutter 50 rotates at a given speed at the outside of the cover 42, and cuts the puffed grains g2 in desired size. A reference numeral 55 in FIG. 1 denotes a motor for making the

cutter 50 rotate.

Hereinbelow, a process of puffing grains will be described, and simultaneously the operation, function, and effect of the respective components of the grain puffing apparatus according to the embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3.

In FIG. 1, a fixed amount of grains gl per unit time is input into a space that is formed by the screw 20 and the cylinder 30 through a hopper "H" and through the grain inlet 33 of the cylinder 30.

If grains gl are input through the hopper "H" and through the grain inlet 33 of the cylinder 30, the grains gl are moved to the puffing unit 40 while the screw 20 rotates by the motor 10. The grains gl make a friction with one another during the process that grains gl move to the puffing unit 40, and the grains gl make a friction with the outer circumferential surface of the screw 20 and the inner circumferential surface of the cylinder 30, to thereby generate frictional heat. The grains gl are changed into a gel state by the frictional heat, as the grains gl moves from the grain inlet 33 to the puffing unit 40. Accordingly, water existing in the inside of the grains gl evaporates, and the pressure in a space (hereinafter referred to as a puffing space) which is formed by the screw 20 and the cylinder 30 increases together. Grains gl move toward the puffing unit 40 continuously at the high temperature and high pressure state.

Meanwhile, when grains gl move at the state where proper temperature and pressure are kept, puffing is attained properly. The internal temperature and pressure of the puffing space are sensitive to react to the temperature of the input grains, the water included in the grains, and the external temperature

of the grain puffing apparatus.

The temperature in the puffing space should be kept at 130 ⁰ C or so, in this invention. This is because nutrients of grains are destroyed in the case that the temperature in the puffing space becomes 150°C or higher, as described above.

In the case that the temperature in the puffing space is a certain temperature or high, vapor that is evaporated from the grains gl flows backward, and heats the grains gl which are input into the grain inlet 33. Accordingly, as soon as the grains gl are input, the grains gl are changed into a gel state. As a result, there is a problem that it is difficult to make the grains gl transferred. Since the temperature of grains is lower than that of the puffing space, the grain puffing apparatus is cooled by the grains. Thus, if input grains are immediately heated, there is a problem that a cooling effect of the grain, puffing apparatus by grains cannot be expected. In order to prevent vapor from flowing backward, a screw groove 24 is formed. Since grains of a gel state is engaged with the screw groove 24 in a ring shape, a kind of a wall is formed to prevent vapor from flowing backward toward the grain inlet 33.

Meanwhile, since vapor does not flow backward by the grains filled in the screw groove 24, the vapor in the puffing space is discharged through the grain inlet 421. Here, in the case that the vapor pressure in the puffing space is very high, the temperature in the puffing space rises up, to thereby make an influence upon an efficiency of puffing. Accordingly, in the case that the vapor pressure in the puffing space becomes a certain pressure or high, it is necessary to discharge vapor through a path other than the grain outlet 421.

For this reason, the puffing unit 40 includes a main body 41, a cover 42 and a clamp 43. As described above, the main body 41 and the cover 42 are fixed by the clamp 43, and the clamp 43 is of a mechanically deformable structure. Accordingly, in the case that the vapor pressure in the puffing space becomes a certain pressure or high, vapor is discharged through a minute gap between the main body 41 and the cover 42 by the vapor pressure.

By this configuration, the temperature and pressure in the puffing space are kept constant.

The grains gl which have been transferred toward the cover 42 through the puffing space are discharged through the grain outlet 421. Here, since the atmospheric pressure is relatively smaller than the pressure in the puffing space, the puffing space is expanded.

Meanwhile, since the inner circumferential surface of the cylinder 30 is gradually reduced lengthily, the puffing space is gradually reduced during the transfer of the grains gl. Accordingly, the friction between the grains gl increases, to thus provide an effect of increasing a self-generation of heat as the grains gl are transferred toward the puffing unit 40.

If the puffed grains g2 are discharged through the grain outlet 421, it should be easy to cut the puffed grains g2 into a desired size and package the cut grains g2, to commercialize the puffed grains g2.

Accordingly, the cutter 50 is rotated using the motor 55 for the cutter 50, in order to cut the puffed grains g2 into a desired size.

As described above, the grain puffing apparatus according to an embodiment of the present invention which has a structure that the inner diameter of the cylinder decreases gradually, has been described, but even in

the case that the inner diameter of the cylinder is kept equally can achieve an objective that the present invention attains. It is apparent to one skilled in the art that such a modification or variation should be included in the technological thought of this invention. As described above, the grain puffing apparatus according to an embodiment of the present invention which has a cutter has been described, but the objective of the present invention may be accomplished although the grain puffing apparatus does not include the cutter. It is apparent to one skilled in the art that such a modification or variation should be included in the technological thought of this invention, even in the case that the grain puffing apparatus does not include any cutter.

As described above, the grain puffing apparatus according to the preferable embodiment, of the.present invention has been described. . However, the present invention is not limited to the above embodiment, and it is possible for one who has an ordinary skill in the art to make various modifications and variations of the grain puffing apparatus, without departing off the spirit of the present invention.

As described above, the present invention provided a grain puffing apparatus which can enable puffing of grains without using a heating source, and efficiently discharge heat which is generated during puffing, to thereby prevent vapor from flowing backward and enable a continuous operation of the grain puffing apparatus.

Industrial Applicability As described above, a grain puffing apparatus according to the present

invention puffs grains such as uncleaned rices, rices, corns, and beans in an extrusion method without a special heating apparatus, and efficiently discharges heat generated in the inside of the grain puffing apparatus and enables puffing of grains without stopping of operation due to excessive heating of the grain puffing apparatus.