MXPA01000305A - Continuous shock wave food processing with shock wave reflection - Google Patents

Abstract

Water and meat pieces (P) are pumped through a conduit (100), the walls of which are made of plastic having an acoustic impedance close to that of water. The conduit is immersed in a tank (400) full of water. A shock wave generator (200) (chemical explosive or capacitor discharge electrodes) creates a shock wave in the water. The shock wave passes through the conduit without substantial reflection because the impedance of the conduit wall matches the impedance of the water. The shock wave tenderizes and at least partially sterilizes the meat. A heavy-duty shock-reflective cylinder reflects portions of the shock pulse onto the conduit. Continual explosions are repeated rapidly enough that all of the meat passing through is tenderized. Alternatively, the meat is packed in water within a closed container in place of the conduit.

Description

PROCESSING OF FOODS BY CONTINUOUS SHOCK WAVES WITH REFLECTION OF SHOCK WAVES CROSS REFERENCE WITH RELATED APPLICATIONS This application claims the benefit of three US provisional patent applications, all from the present inventor: serial number 60 / 115,610, "Continuous Treatment of Hamburger", filed on January 12, 1999; serial number 60 / 126,932, "Improvements in Treating Meat by Explosive Discharge", filed March 29, 1999; and serial number 60/091, 621, entitled "Treatment of Meat", filed July 2, 1998. The contents of the three applications are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION The present invention relates to the treatment of meat by shock waves, to effect softening and / or killing of microorganisms.

BACKGROUND OF THE INVENTION The meat can be softened and at least partially sterilized by shock waves (acoustic or pressure pulses), from explosions typically caused by a charge of chemical explosives or a capacitive discharge between two electrodes, as shown in the United States patents. United of John Long 5,273,766 and 5,328,403, and pending applications. A shock wave travels outward from the site of the explosion at the speed of sound (or somewhat higher in the case of high-intensity shock waves) and, as an audible sound echoing from a wall, will reflect from a reflective surface of shock waves. The condition for reflection of a shock wave is that the speed of sound, which varies depending on the medium through which it travels, changes on a surface of separation between two media. A pressure wave travels in water at approximately 1500 meters per second; the same wave travels in stainless steel at 5800 meters per second, almost four times faster. This difference in the speed of sound is close to the difference in velocity for shock waves, which are basically high-pressure sound waves; These are propagated by the same mechanism by which sound does, but they are peak pulses and typically have a much higher sound intensity or pressure increase (sometimes called "overpressure") than most sounds.

When a shock wave or sound in the water encounters a steel surface, most of the wave is reflected from the surface due to the difference in velocity (also referred to as "acoustic impedance imbalance"), passing only a small portion through steel. In the related technology mentioned above, the reflection of shock waves from a thick steel surface was used to increase the intensity of the shock pulse. The pulse of the shock waves of an explosion is short, but it has an appreciable length, and when the pulse is reflected from the steel it passes through it, increasing the pulse intensity of the shock wave. (The same effect is seen on a boardwalk, where ocean waves reflecting from the dike, splash to a much higher height above the levee than the height they reach in the open sea.) In a preferred mode according to 766 and 403 of Long, the meat was placed in plastic bags, which were lined up along the bottom of a hemispherical steel casing, the cover was filled with water and an explosion was initiated at the geometric center. The shock wave traveled outward to reach all the meat at about the same time, and struck the meat with approximately the same overpressure or shockwave intensity, passing through the packing film and meat twice due to reflection from the steel cover. (Bearing meat and packing bags an acoustic or mechanical impedance close to that of water, they do not reflect appreciably the shock pulse.) This mode works very well in softening and at least partial sterilization of the meat aligned to long and adjacent to the inner wall of the roof, but it has some disadvantages. In an outstanding manner, this mode is inherently a batch operation, and the equipment is expensive. A stainless steel hemisphere of 1.22 meters in diameter and 5.08 cm in thickness is not cheap, and the equipment required to move blast shields, water changers, etc., is complex and expensive. Packing and removing meat is slow, and additional delays are assigned due to safety issues; workers should not load the hemisphere while handling the explosive, for example. Another disadvantage is that the water flows up and out of the hemispherical shell due to the explosion, and must be filled again. In the case of chemical explosives, it is preferable to drain any remaining water and exchange it for fresh water, which is free of chemical byproducts of the explosion, even though this water does not come into direct contact with the meat. This drained and filled takes time and uses a large amount of water. In addition, the explosive force in the aforementioned mode is not balanced. The gas geyser of the explosion, vapor and spray out of the upper part of the hemisphere, causes a great reaction force which drives the hemisphere upwards, and this must be resisted by large springs, shock absorbers, etc., this additional equipment being expensive too. A special explosion protection dome on the cover is required as in the United States patent of Long 5,841,056 to absorb geyser strength. Putting meat in protective plastic bags can cause problems because some air bubble, which remains in the bag along with the meat, will act as an acoustic "lens", focusing the shock wave (this is similar to the effect of convergent lens of a drop of water with light) on the flesh just on the other side of the bubble, causing a very high local pressure, which can "burn" the flesh. The heat generated in this way will often also burn a hole in the plastic bag, causing it to break. The placement of the meat against or very close to the reflective shock wave steel surface is the root of some of the difficulties with the previous modalities as discussed above, and such placement has limitations that prevent any substantial improvement. The width of the layer of meat that can be softened is limited by the duration of the shock pulse, because all the meat is going to be subjected to duplicate intensity, then the thickness of the shock pulse must be at least twice the thickness of the meat, so that the intensity of the pulse doubles through the thickness of the meat. If the pulse is of a very short duration, its front flank will pass the layer of meat just as the front flank is reflected from the steel, and only the portion of meat closest to the steel will experience the doubled shock intensity; the rest will suffer two passes of the unduplicated shock wave. The pulse width of the wave in meters is close to 1500 m / s, divided by the duration of the pulse in seconds. Limiting the thickness of the meat means that the size of the hemisphere should be increased, if each batch of meat to be treated will be large enough so that the overall processing speed is not too slow. But increasing the diameter of the hemisphere means that the shock pulse will be weaker, because the pressure intensity of a spherical wave is reduced approximately as the radius cube does (which corresponds to the distance from the source or sources of the explosion).

BRIEF DESCRIPTION OF THE INVENTION If the intensity of the previous modalities were not emphasized, then the layer of flesh could be separated more from the reflective inner surface of shock waves of the hemispherical shell, and the greater intensity of the shock wave would recover the duplicated intensity. If the flesh moved inward at approximately 29% of the radius of the hemisphere (accurately, 1,000 minus 0.707), then the one-pass shock wave intensity would be just as great as the intensity duplicated on the inner surface of the hemisphere. the hemisphere, even if the energy of the explosion does not increase. (The shock wave would pass out through the flesh and then, after reflection from the steel surface, it would go back inward through the flesh.) This shows that placing the meat directly on or adjacent to a Reflective surface is not essential. However, the problem arises of how meat can be supported so that the explosion does not release it. The present invention employs a container for meat which, unlike thick stainless steel, has a reflectivity as small as possible, so that the shock wave passes freely through it. The container can be made "acoustically transparent", that is to say, with a mechanical or acoustic impedance approximately equal to that of water, so that a sound wave or a shock wave passes through the container without being deviated significantly in its direction, or delayed in its passage. There are several ways to make an acoustically transparent container. One is to make the wire container, which can pass the sound (and a shock wave) around, but a wire container will not adequately support the meat in all cases, and depending on the sizes of the wires or rods of which it forms, will interfere with the shock wave. A preferred way, then, is to make the container of a material that has the same "acoustic impedance" as the liquid in which it is going to be submerged. If the impedances of the material of the container and of the liquid are approximately the same, then the shock wave will have approximately the same speed in both materials. According to Huygens' principle, the waves will not deviate by refraction. Neither will they be reflected from the separation surface between the liquid and the container material. (An analogy with light waves can be made.) If a solid object submerged in water has a "refractive index" (optical impedance) close to that of water, it will be almost invisible because the light rays passing through it For example, a piece of glass or clear ice is less visible in the water than in the air, because there is little difference between the refractive indexes.) If the liquid is water as preferred, the container can be be made of a material in which the speed of sound is similar. Such materials are available. In rubber rubber, for example, the speed of sound is only 3% higher than in water, and plastics several times more durable have acoustic impedances sufficiently close to that of water to be very suitable for the meat container. A suitable and well known material, whose use is approved for food, is TYGON, which is a plasticized vinyl polymer; others are polyethylene and polypropylene. The acoustic transparency and durability of other plastics in the explosive environment can be routinely tested. If a container of hemispherical meat made of TYGON or the like were suspended concentrically within the hemispherical shell, the meat could be softened without the need for reflection, as discussed above. But this would not eliminate the problems with the previous modalities, namely the need for batch processing and the associated slowness and complex equipment. To achieve any continuous procedure, semi-continuous or intermittent, or improved batch processing, the present invention exchanges the previous hemispherical geometry for an essentially cylindrical geometry, while in some embodiments the batch container is exchanged by a conduit (for example a TYGON tube), a through which the meat product is pumped or carried in the case of hamburger or the like (i.e. a suspension), or by water flow in the case of pieces of meat, for example boneless chicken parts or wrapped beef in plastic film. The advantages of a solid plastic tube of adequate impedance, substantially transparent to the shock wave, compared with a conduit made of fine mesh, are evident in relation to the transport of food; A tube of this type is also more "transparent" to shock waves than a mesh or frame. TYGON and other suitable plastics are available in the form of tubes. Instead of the steel hemisphere of the previous embodiments, the present invention preferably provides a nearly hollow cylindrical shock reflector surrounding the plastic conduit or the static socket and the explosion site, so that the shock waves are reflected internally. Even if the geometry is not so precise that the reflections of the shock waves are perfectly arranged, the reflector serves as a reverberant chamber in which the echoes of the shock waves produce a quasi-hydrostatic pressure pulse.

As the meat is pumped through the plastic conduit in the case of this continuous system, explosions are initiated near the conduit repeatedly, at intervals sufficiently short so that all the meat passing through the conduit is exposed to the treatment by shock waves. All shockwave reflections are preferably from surfaces at a distance from the plastic conduit and the meat. The meat in this continuous process is preferably subjected to several passes of shock waves in short succession, which creates the effect of quasi-hydrostatic pressure wave of overlap pulses, either through overlap of shock waves and a consequent increase in the intensity of shock, or by failure of the meat or bacteria in it to "recover" from a shock before the next shock that arrives quickly. Shock waves can impact the flesh either directly, by reflection, or after several reflections from a number of surface areas of the reverberating cylindrical chamber. The provisional applications of the present inventor describe arrays of multiple explosions, which use a number of electrode charges. The arrangement of multiple explosions has many advantages, including nullified recoil by cancellation of explosive pulses, and easy adaptation to continuous processing. The use of several explosions creates the need for precise synchronization of the explosions, if their shockwaves are going to hit the plastic conduit and pass through the meat simultaneously. Timing is especially important to achieve desired quasi-hydrostatic pressure softening. If the charges or electrodes are the same distance from the conduit, the synchronization requirement is that the explosions are synchronized in a precise manner. The inherent problem to achieve high precision in synchronization of explosions when there are several sources of explosion, can be avoided by using a single explosion from which the shock wave converges on the duct due to reflection (or refraction) of the wave crash. In this case, the only requirement for synchronization is that the requirement is not precise that the explosions are sufficiently frequent and regular so that all the meat that passes through the plastic conduit is exposed to the shock waves. From a single explosion, a spherical shock wave expands rapidly and uniformly until it finds a change in acoustic impedance, and is reflected or refracted. With an adequate arrangement of reflective surfaces, the expanding spherical shock wave of the single explosion can be deflected and reflected so that the reflections affect the meat in the conduit from several directions in a short time. If the "rays" (portions of the wavefront that travel perpendicular to the surface of the wavefront) travel all the same distance to reach the conduit, then the waves will impinge on the flesh inside the conduit simultaneously.

The present invention greatly accelerates the processing of meat (or other products) by moving the reflective surfaces of shock waves farther from the meat and by placing and supporting the meat with the use of an acoustically transparent duct, and by providing the reflective surface of waves of shock in the form of a cylinder or its equivalent. The present invention thus fulfills a main objective of providing improved treatment, and also fulfills the objective of overcoming other deficiencies in the previous modalities noted above.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other objects and the nature and advantages of the present invention will become more apparent from the following detailed description of embodiments taken in conjunction with the drawings, wherein: Figure 1 is a partial schematic perspective view of the invention. Figure 2 is a cross-sectional view, taken perpendicular to an axis of the duct, of a first embodiment. Figures 3a and 3b are an elevation and schematic view of a second embodiment. Figure 4 is a schematic view of a third embodiment. Figure 5a is a plan view of a cylindrical reflector inside a cylindrical-hemispherical tank; Figure 5b is an elevation view of the arrangement of Figure 5a; Figure 5c is a plan view of a meat container inside the cylindrical reflector; Figure 5d is an elevation view of the container of Figure 5c; Figure 5e is a side view of an explosive strip; and Figure 5f is a front view of an explosive strip. Figure 6a is a plan view of the tank with movable cylindrical reflectors; and Figure 6b is an elevation view of the arrangement of Figure 6a.

DETAILED DESCRIPTION OF THE PREFERRED MODALITY Here, and in the following claims: "Shockwave", "acoustic pulse", "peak pressure" and similar terms, are generally used interchangeably. All describe an acoustic wave or a pressure wave that travels at the speed of sound (or above it). Terms like "shock wave" also include high-energy square waves, sine waves and the like generated by underwater horns and sirens. A sound that has a frequency is simply a repetition of shock waves, and by the Fourier theorem, a shock wave is composed of frequencies. The present invention contemplates the treatment of food products by means of high intensity sounds, whether discrete pulses or not; and "conic section" has the usual mathematical definition: circles, ellipses, parabolas, etc. Figure 1 shows the invention in schematic and theoretical overview. A food product P, which may be eg boneless chicken parts in water as illustrated, or in its place a semi-solid hamburger cylinder, i.e. a meat suspension, is moved through a plastic conduit or other conduit transparently acoustic 100 in the direction of the large arrow A, driven by a mixer / pump 120 coupled to a feed tube 110. Water W, contained in a surrounding tank 400, surrounds the duct 100; for clarity, only one corner of the tank 400 is illustrated. The sectioned side of the conduit 100 is coupled to another pipe (not shown), or to other means for delivering the food product P from the tank 400 for further processing. As indicated above, conduit 100 is preferably made of a plastic or other impedance material acoustically matched to that of water, the preferred liquid. Inside the conduit 100, the food product or mixture of food pieces and water, is composed mostly of water. Therefore, the region of the conduit 100 consists of either water or substances which are acoustically similar to water, and therefore, this region is substantially, acoustically homogeneous. Shock waves or sounds can pass through it without great deflection or reflection. Adjacent to the conduit 100 is a wave generator, preferably an explosive device 200. This may be a chemical explosive, for example in the form of a strip, a group of spark electrodes, or a mechanical device which produces a shock wave or a comparable sound of sufficient energy (for example a siren). The explosive device 200 is coupled to a knock circuit or a capacitive discharge release circuit 220, which controls the timing of the explosion and also provides energy for the explosion in the event of generation of electromechanical waves or electric shock (e.g. this includes capacitors). Before the detonation or discharge, a shock wave expands outward. A portion of the shock wave passes directly through conduit 100 as indicated by arrow S1. Other portions of the shock wave, labeled S2 and S3, are reflected from the reflection surface of shock waves, represented here by dances or reflectors R1 and R2, which in theory can be, for example, steel plates mounted on springs. heavy, and pass through conduit 100 as indicated by the corresponding arrows. However, it should be understood that this figure does not show an important feature of the present invention, namely, the shock reflective chamber having a conical section which eliminates the need for springs or similar devices.

It will be seen that the passage of the shock waves S1, S2 and S3 can generally be done simultaneously by appropriate positioning of the reflectors R1 and R2. Alternatively, two shockwave generators 200 may be symmetrically placed on either side of the conduit 100 (not shown in Figure 1); this arrangement also provides balanced pulses on the conduit 100 when the two generators 200 are exploded simultaneously. Also, there could be three wave generators spaced 120 °, and so on. In place of water, any liquid (or even gas) can be used to transmit the shock waves through the tank 400 and / or to transport the food product P; in particular, a mixture of water and substances such as salts, pH adjusting substances, disinfectants, surfactants, etc. can be used. In this case, the acoustic impedance of the conduit 100 can be adjusted accordingly by appropriate selection of the material from which the conduit is made. It is noted that the liquid in the tank 400 may be different from the liquid in the conduit 100. These two liquids may have somewhat different acoustic impedances, but these are preferably as close as possible. If the acoustic impedances of the conduit 100, the first liquid and the second liquid are all generally similar, then the shock waves passing over the conduit will not deviate substantially (will not be reflected or refracted), and the meat P within the conduit 100 It will be treated as desired. In its broadest, but not preferred, form, the invention contemplates dropping food pieces or extruding food vertically through water without the use of a different conduit. In such an arrangement, the explosive device 200 and the cylindrical reflector will be deployed around a vertical axis instead of the conduit 100, that is, the conduit could be absent. However, such a modality requires a difficult and careful balancing of the shock waves, in opposite directions to prevent the pieces of meat from being thrown. Figure 2 is a cross section of a first preferred embodiment, taken on a plane perpendicular to the axis of the tubular plastic duct 100, which is filled with pieces of meat (e.g., pieces of chicken, beef wrapped in a film of plastic or hamburgers) and liquid flowing in a direction that enters or leaves the plane of the paper. The conduit 100 is immersed in the liquid 401 filling the tank 400, and this liquid 401 also fills the annular space 302 of the cylinder 303 appearing in the cross section of Figure 2 as an opening generally in the form of a football. The cylinder 303 includes a generally concentric cylindrical interior surface 307 of a heavy chamber wall, and two parabolic surfaces 301. The explosive device in this embodiment includes two pairs of electrodes 201, each of the four electrodes having a respective insulating cover 203 , each pair coupled to a capacitive discharge device (not shown in Figure 2) such as that described in WO 98/54975 and in a US patent application correspondent. The exclusive electrical parts of the electrodes are kept dry by a waterproof protection 205. The distance between each pair of electrodes 201 is geometrically centered on the focus of the surrounding parabolic reflecting surface 301. The two parabolic reflecting surfaces (paraboloids of revolution) they share a common axis, shown by a line of dashes and dots. When a discharge occurs through any pair of electrodes, the sudden release of energy creates a shock wave followed by a gas bubble. Most of the shock wave (in terms of spherical angle) is reflected from the parabolic surface, creating a flat shock wave which continues from the shock generator directly through the cylindrical chamber, through the conduit 100 and the meat inside it, and on the opposite parabolic reflector, which reflects the shock wave for the second time, on the other pair of electrodes. The convergent shock wave can create a secondary local pressure increase, from which the wave can radiate again causing some reverberation of forward and backward. Other portions of the shock wave will bounce off the cylindrical surface 307, and the meat, water and conduit 100 will refract to some degree the shock wave. As a result of multiple reflections and refractions, the shock wave will reverberate within the cavity, causing an increase in quasi-hydrostatic pressure. Both pairs of electrodes 201, desirably are discharged simultaneously, doubling the energy imparted to the food product and avoiding any net imbalance of force on the conduit from the subsequent shock wave or gas bubble. The cylindrical surface 307 is preferably as long as its diameter, and the ends of the explosion-containing cylinder 303 (surrounded by the cylindrical surface 307) are preferably open to allow water to flow from the sides due to the force of the gas bubble created by the explosion (that is, the water moves in and out of the plane of the paper). The explosion is contained in radial form by the strong walls of the cylinder, which are preferably made of stainless steel. Due to the cylindrical symmetry, the impulse imparted to the flesh is balanced, and there is no need for force that tends to throw the flesh, or the conduit, away from its central position, while the explosions are simultaneous and of equal energy. If only one of the shock generators creates a shock wave, then there may be force laterally on the conduit 100, depending on the hydrodynamics after the explosion, and especially of the gas bubble which rapidly follows the wave of shock. After the explosion, the water 401 within the tank 400 will immediately flow back to fill the cavity 302 that surrounds the conduit 100, in time for the next explosion which will treat the meat yet to reach the shockwave zone between the reflectors parabolic The continuously moving food product is continuously treated by continuous repeated explosions at the electrodes, creating shock waves within the reverberant cavity. Alternative embodiments to that of Figure 2 (not shown) include various placements of the electrodes and their parabolic reflectors. Instead of the two diametrically opposite impact generators with 180 ° separation illustrated in FIG. 2, three shock generators can be used with 120 ° separation, four with 90 ° separation, and so on. The shock generators can also be staggered along the axis in sets, and so on. The axially separated explosions can be simultaneous or in sequences. Figure 3a illustrates a second embodiment in which only one shock generator is used, but in which the shock waves strike the duct from opposite directions, creating a balanced force and an increase in the quasi-hydrostatic pressure. Inside the tank 400, an explosion chamber 210, a treatment chamber 310 and a toroidal tube 230 supported on a transverse member 402 are mounted. As in Figure 2, the conduit 100 is perpendicular to the plane of the paper. The ends of both halves of the toroidal tube 230 are coupled in the explosion chamber 210 and the treatment chamber 310, so that the water inside can flow to the right or to the left as shown in Figure 3a. The schematic cutout 3b illustrates how the sections of the toroidal tube 230 are connected to the treatment chamber 310. It is noted that a discharge wire 207 passes from the exterior to the explosion chamber 210 in Figure 3a. An explosion inside the explosion chamber 210 creates shock waves traveling inside the toroidal tube, bouncing off the reflective curved surfaces of the tube 230 as they progress, and arriving at the treatment chamber at the same time thanks to the equal lengths of the two sections of the toroidal tube that couples the explosion chamber 210 to the treatment chamber 310. Impact of the balanced shock wave of the opposite sides avoids a lateral force in the transparent shockwave conduit and that contains the flesh 100; and the use of a single shock generator obviates the need to synchronize two or more shock generators at any axial location. The present invention includes the use of more than two tubes to convey shock pulses in a balanced manner to the treatment chamber 310. Any number greater than two can be used, and if they are of equal length they can be of any shape. Figure 4 shows a third embodiment of the present invention. Here, the cylindrical surface 307 of FIG. 2 is flattened in a chamber having a surface 307 'with an elliptical cross section. In one focus of the ellipse is the pair of electrodes 201, and centered in the other focus is the duct containing the flesh 100. A geometrical property of the ellipse is that the rays of a focus, internally reflected from the interior wall of the elliptical camera 307 ', converge on the other focus. Thanks to this property, the shock wave of the electrode 201 will converge on the conduit 100 from all sides and will impinge on all points on the surface of the conduit at the same time, except that the shock wave that comes directly from the electrode 201 will pass to through the conduit 100 before the arrival of the shock front readjustment, it will bounce off the distant wall, and then strike the conduit again at the same time that the rest of the shock front reaches the outside of the conduit. If the explosion comes from a point, as from a pair of electrodes like those in Figure 2, then the shock wave will not converge precisely in the center of the duct, except in direct opposition to the explosion. Convergence in other locations along the canal will not be precisely centered. If the shock wave comes from an in-line explosion (for example, an explosive strip in the same position as the electrode in Figure 4), the shock wave will strike the conduit 100 at the same time and uniformly throughout. of its length corresponding to the length of the strip explosive. The same convergence of shock waves in the conduit shown by the elliptical shape of Figure 4 can be achieved with acoustic refractive lenses. Said lens (not illustrated) can be made by immersing in the tank 400 a hollow shell filled with air having the shape of an optical convergence lens. In the case where a conduit or container made at least partially of materials inferior to those that perfectly agree in impedance with the surrounding liquid, the wall of the conduit or container (or the same portion thereof) can act as a lens to control the convergence and / or divergence of the waves in the liquid inside or outside the container / conduit. Two other alternative and preferred embodiments are illustrated schematically in Figures 5a-5f and 6a-6b. Figures 5a-5f illustrate a static or batch system, and Figures 6a and 6b illustrate a continuous or semi-continuous (intermittent) system that relates to a conveyor. As illustrated, both embodiments utilize strips of chemical explosives 520 placed against the inner wall of a reflective steel cylinder of shock waves 530 with an interior cylindrical surface 307"which acts as a reflector, both systems can also be adapted to use explosion by discharge electrical instead of the explosive strip 520 (not illustrated in Figures 5a-5f.) The explosive strips 520 are preferably adhered to metal brackets 522 having upper hooks 523 that engage on the upper edge of the reflective wave cylinder 530. The chemical explosive strips 520 preferably used in the illustrated embodiment have a sticky back side This explosive is commercially available in sheets and can be cut into strips which are then placed in metal brackets 522 hanging from the upper edge of the 530 cylinder. The 522 clamps can be installed in a matter of seconds throughout the entire inside the cylinder. Strips 522 survive the explosion and can be used repeatedly. A preferred embodiment of cylinder 530 is open at the ends, made of stainless steel with a 5 cm thick wall, 66 cm long on the shaft and with an internal diameter of 132 cm. Lifting eyes 531 can be found along the upper edge of cylinder 530. In the embodiment illustrated in Figures 5a-5f, the meat is placed in a cylindrical container 500 (illustrated in Figures 5c and 5d) having a body 502 and a hermetic lid 501 held therein, so that by frictional forces or rotating means of various types, and preferably, the container 500 made of plastic material, for example TYGON, having an acoustic impedance close to that of water. Accordingly, the container 500 corresponds to the conduit 100 of the modalities described above. The lid 501 preferably has a check valve to allow the liquid to escape when the air bubble compresses the container 500. Preferably, the diameter of the container 500 is less than the radius of the open stainless steel cylinder of the ends 530 around 20 cm, which results in a 10 cm ring between the container 500 and the wall of the reflective cylinder 307"of the cylinder 530. In the experiments carried out, the container 500 was a RUBBERMAID trash can available on the market which is formed from plasticized vinyl plastic Figures 5a and 5b illustrate an optional basket 450 which may be made of a 0.6 cm diameter stainless steel bar with holes of approximately 10 cm In a non-preferred embodiment, the basket 450 it can be used to support and retain the plastic container 500 and can be supported by itself on a support 454. Even in another embodiment, the container 500 can be removed and the meat can be packed directly into the basket 450, but this is also not preferred for the reasons already mentioned. The complete assembly, immersed in water in the tank 400, may remain at the bottom of the tank which may have a hemispherical shape generally, as illustrated in Figure 5b, although the shape of the tank 400 is irrelevant. The container 500, and / or the basket 450 and the support 454, can be placed in the hemispherical tank or other structure containing water by means of a crane (not shown). Other types of supports can be used instead of the support 454. In Figure 5b, the cylinder 530 is almost 30 cm apart from the hemispherical bottom of the tank 400. This space is large enough to allow the gas bubble to vent without moving the cylinder 530. As already indicated, the use of a single closed container with a suitable support is preferred for holding it in position without the open basket 450. As already explained above, said container 500, preferably is watertight and is formed of a material that is acoustically similar to water, for example plasticized vinyl plastic, which is filled with meat and then filled with inert liquid or to treat meat, for example, water or additives containing water. The chemical explosive in strips 520 is placed in locations of 90 ° around and along the inner wall 307"of the cylinder 530 as best illustrated in figure 5a, and extends to the height (length) of the cylinder, however, length, thickness, width and placement of the cylinder may vary. explosive strips It has been found that when the explosive is detonated at a distance of about 10 cm from the meat in a bag packed with the container 500, no burn or rupture of the bag around the meat occurs. Harder cuts of meat subjected to this treatment have improved by 50% softening with the use of previous modalities, in which the meat is placed against or in adjacent position near the hemispherical wall of the tank 400. The present invention and in In particular, the modalities of Figures 5a-5f and 6a-6b have several advantages compared to previous methods and apparatuses: 1) All the energy of the explosion is directed inwards towards the meat, so that s all the energy of the explosion acts in the meat to effect the softening and / or destruction of microorganisms on or in the meat. In the absence of the cylinder 530, 303, 310, for example in the use of the hemispherical tank 400 with explosive discharge occurring in the focus of the hemisphere, half of the energy is directed upwards causing displacement of the tank water, while only the other half is directed downwards and outwards towards the meat. For example, with the strip explosive, the energy of the explosive that would otherwise be directed radially outward is reflected back inside the cylinder wall in the same direction as the rest of the explosive discharge. In theory, half of the strip explosive should be needed, compared to the amount used when the meat is placed lengthwise or in an adjacent position, and the explosive discharge is made at the focal point according to previous modalities. 2) The cylindrical packing of the meat inside the container 500 of the embodiments of figures 5a-5f and 6a-6b simplifies the handling of the meat and the manufacture of the container, either in the form of an open basket or a material which is an acoustic similar to water. A problem in previous modes was the failure of the meat wrapping material, which sometimes failed as a result of exposure to the shock wave or to the gas bubble. In previous modalities, since the meat in bags was in the same water that was exposed to the explosive discharge, in case the bag failed some of the water would come into contact with the meat, and that water contained chemicals that resulted from the explosion and probably stained the flesh. The use of a waterproof container 500 containing the meat and drinking water in accordance with the present invention solves this problem. For example, if a cylindrical container in which the meat is loaded is filled with potable water and sealed, the meat can not come into contact with the water outside the container even if a meat packing bag ruptures. The same is true with respect to the modes of continuous movement of Figures 2-4. 3) The use of a reflective shock wave cylinder, especially with explosive strips placed in vertical position against the inner wall of the cylinder as in Figures 5a-5f and 6a-6b, produces balanced detonation forces. The shock waves reflected inside the cylinder produce a circumferential tension inside the cylinder, but the forces are balanced and the cylinder does not move as a result of the explosion. The same effect is achieved with electrodes placed in a suitable manner, for example inside cavities found in the inner wall of the cylinder (not shown). The forces are similarly balanced in the modalities of Figures 2-4. The hydrodynamics of the present system produce shock waves that propagate from the wall of the reflective cylinder of shock waves and impact on the meat packed inside the basket. This causes the pressure to double, and in successive reflections produces a quasi-hydrostatic pressure environment that lasts for more than 100 microseconds. Except in the special embodiment of Fig. 4, the inner wall of the reflective shockwave cylinder must be separated in an adjacent position close to the basket to produce this effect, since the wall acts as a reflector and contains the shock waves for the impact. The use of an inner waterproof basket containing drinking water together with the meat offers another advantage, as it allows the meat to be packaged in a less expensive wrapper. If the shock wave generated by the explosion causes a tear or rupture in the plastic wrap, the meat will not suffer any damage in any case because it is surrounded by drinking water. Figures 6a-6b illustrate a related embodiment in which preferably the same cylinder 530 is used as in the embodiment of Figures 5a-5f, but with trunnions 532 or the like and other minor modifications. The two open ends of the heavy duty shock wave reflective cylinder 530 once again produce a balanced force, so that the cylinder 530 does not move as a result of the explosion, because the gas bubble is extinguished with equal force from both open ends of the cylinder. The embodiment of Figures 6a and 6b employs a conveyor or rail 650, schematically illustrated, for continuous or intermittent (semi-continuous) operation. The conveyor 650 can for example be a set of continuous webs that move on rollers and have spacings for the stumps 532 of the cylinder 530. The meat P is packed inside the container 500 as in the other embodiment of FIGS. 5a-5f, centered on the 530 steel cylinder.

Figures 6a and 6b illustrate an elongated tank 400, preferably 2 cm thick of stainless steel, embedded in concrete. This elongated and simplified tank provides an improvement over the mode of Figures 5a-5d as illustrated, due to the high cost of the hemispherical tank and its support structure, which can weigh many tons. The tank 400 of figures 6a-6b can be quite large, for example 4.20 m long, 2.40 m wide and 2.40 m deep. A curtain of bubbles may be placed around the sides of tank 400. The large size of tank 400 tends to reduce the reaction of its walls to the shock wave and to the gas bubble; however, additional shock absorbing structures are preferably included. For example, below the location of the cylinder 530 in which the explosive discharge will occur, a steel plate 672 is located at a distance of approximately 0.9 m from the bottom of the cylinder. This steel plate 672 has, for example, a diameter of 1.8 m and 8 cm in thickness. The steel plate 672 is supported by the springs 674, preferably Belleville springs, at the bottom of the tank. Also, shock absorbers 676 are preferably provided, which act as shock absorbers to mitigate the downward force of the shock wave and the gas bubble. The springs 674 return the plate to its previous position after the deformation caused by the explosion. The energy of the water entering with upward force is absorbed by an explosion shield 671 located on the tank.

The shield of preference is not attached to the tank itself due to the ascending kinetic energy in the water, resulting from the expanding gas bubble. In operation, the container 500 filled with water and meat is placed in the heavy duty cylinder 530 by arrangements such as those in Figures 5a-5f, probably with the use of a crane 632 due to the substantial weight involved. The cylinder 530 is coupled to the conveyor 650 which moves the cylinder 530 to the explosion position under the shield and below the water level. After the explosive discharge, the cylinder 530 moves again, preferably to the opposite end of the tank from where a 632 crane withdraws it. While this occurs, another cylinder descends into the tank and is placed in position to fire. (Alternatively, the cylinder 530 is carried in a circular path, so that it returns to the starting point, and it can be placed to obviate the need to stop at the trigger point). With said continuous or semi-continuous system it is estimated that at least the quantity of product can be softened at the same time as with previous modalities, in which the meat is placed along or adjacent to the surface of the tank. hemispheric. Since Figures 6a-6b of the system do not employ the hemispherical bottom tank illustrated in Figures 5a-5f, the cost of the system is substantially reduced. In the following claims, an acoustic impedance of a duct material is "similar" to the acoustic impedance of the surrounding liquid if a shock wave incident on the duct is refracted or reflected on the duct surface to such a low degree that the liquid food products within the duct are subjected to a sufficient shock wave intensity, in spite of said refraction or reflection, to soften and / or sterilize the food product. It should be noted that the wall of the duct may be in part a function of the thickness of the wall or structure (e.g., porosity). A shock wave can pass through a very thin layer of steel that would substantially reflect the shock wave if the steel were thicker. In this way, materials that have an acoustic impedance that is less similar to that of liquids can be used in the present invention, depending on the geometry. Since the speed of a shock wave can vary with the intensity, and the intensity can vary with the distance of the shock wave generator (chemical charge or electrode), the present invention contemplates the adjustment of the trajectory distance of the explosion to the conduit (including any reflections or refraction) to explain said variations. Also, when the invention employs refraction (ie, acoustic lens formation) to deflect shock waves in the conduit, the delay in transit time from the explosion to the conduit will take into account the different velocity of the shock wave in the middle. of refraction. For example, a bladder filled with air inside a can with liquid changes the angle of a shock wave and by properly shaping the bladder, the shock wave can be refracted in the duct, but the shock wave will be diminished while it is in the air and arrives later than if it had passed through the liquid. The above description of the specific modalities will completely reveal the general nature of the invention, that others may, applying current knowledge, modify and / or adapt easily for various applications of said specific modalities without undue experimentation and without departing from the generic concept, and therefore said adaptations and modifications must and are intended to be encompassed within the meaning and scope of equivalents of the described modalities. It should be understood that the phraseology or terminology used herein is for the purpose of description but not of limitation. The means and materials for performing various functions described can take a variety of alternative forms without departing from the invention. The terms "cylinder" and "generally cylindrical configuration" shall not be used to specify an accurate circular cylinder; consequently, the conduit or container, as well as the heavy duty shockwave reflective container or cylinder, may have an octagonal cross section, for example. The expressions "have the purpose of ..." and "the use is proposed ..." as found in the previous specification and / or in the following claims, followed by a functional sentence, are intended to define and encompass any structure or structural, physical, chemical or electrical element that may exist now or in the future, performing the aforementioned function, either in a precise equivalent or not to the modality or modalities described in the previous specification; and it is intended to give the broadest interpretation to these expressions.

Claims (11)

NOVELTY OF THE INVENTION CLAIMS

1. - A method for treating a food product, especially meat, which uses an explosive discharge to soften and / or at least partially sterilize the meat, characterized in that a first liquid having a first liquid acoustic impedance, a conduit or a container is provided. submerged in the first liquid is adapted to pass the meat through it continuously or is adapted to retain the meat as a container, the conduit or container has an acoustic impedance similar to the first acoustic impedance of liquid and the second acoustic liquid impedance, and where the meat is in said container or passes through the conduit; and the acoustic waves are caused to impinge from more than one direction from a multidirectional acoustic wave generator placed outside the conduit or container in and through the conduit or container, whereby the food product submerged in the second liquid (e.g. Boneless chicken, burgers, pieces of beef) is treated by the acoustic waves that pass through them.

2. The method according to claim 1, further characterized in that the acoustic waves impinge on the conduit or container from more than one direction, generally at the same time.

3. - The method according to claim 1 or 2, further characterized in that the acoustic waves are generated by chemical explosives or by electric discharge.

4. The apparatus further characterized in that it is adapted to perform the method of any of claims 1-3.

5. The apparatus according to claim 4, further characterized in that it has an outer container for containing the first liquid having a first acoustic impedance of liquid; an inner conduit or container is provided for immersing in the first liquid and for containing the food product and the second liquid (for example, burgers, boneless chicken parts in water or pieces of beef wrapped with plastic in water), and the generator Multidirectional acoustic waves are located outside the interior conduit or container to influence acoustic waves in the inner conduit or container from more than one direction.

6. The apparatus according to claim 5, further characterized in that the outer container has a cylindrical configuration in general to contain the first liquid in an annular space between the outer container and the inner conduit or container, and the outer container has a inner wall having shock wave reflection, where the acoustic shock waves that impinge from more than one direction produce an increase of quasi-hydrostatic pressure inside the inner conduit or container, and where the impulses of the acoustic shock waves they are substantially balanced, so that no substantial lateral net force is exerted on the inner conduit or container.

7. The apparatus according to claim 5 or 6, further characterized in that the acoustic wave generator includes a plurality of individual shock wave sources.

8. The apparatus according to claim 7, further characterized in that the sources of shock waves are separated by substantially equal distances from the inner conduit or container, and the explosions in the sources are at the same time substantially.

9. A method according to any of claims 1-3 or to use the apparatus of any of claims 4-8, further characterized in that it is a continuous method wherein the food product is passed continuously through the conduit and is subjected to repeated and sequential shock waves from the generator or shock wave generators, or the method is a batch method in which the food product is packaged inside the container and subjected to simultaneous shock waves from directions opposite and balanced, or the method is semi-continuous or intermittent in which the container is packed with the food product and carried by a conveyor to a location where it is subjected to shock waves from opposite directions in a balanced manner.

10. - The apparatus according to claim 4, further characterized in that it includes a sound wave reflector having an axis and an inner surface substantially surrounding the axis, the inner surface includes in the cross section thereof a generally closed curve; a first liquid having a first acoustic liquid impedance is adapted to be placed inside the reflector; An acoustic wave generator is placed inside the wave reflector and is intended to be immersed in the first liquid; a food product container is available within the wave reflector, the food product container is adapted to pack inside the food product to be treated together with a second liquid, whereby the food product inside the container is adapted to be treated by means of acoustic waves created by the wave generator and reflected by the wave reflector, which pass through the food product.

11. The apparatus according to claim 10, further characterized in that the acoustic wave generator is elongated and in general is placed in a position parallel to the axis, in particular in the form of plural strips of explosive that are placed in opposite opposite positions. and close to the wave reflector.