MXPA97004006A - Microwave energy generating device used to facilitate the removal of concrete from a recipient of me - Google Patents

Abstract

A combination of a concrete mixing container and a device for removing the hardened concrete therefrom, including: a metal container adapted to contain concrete, said metal container having inner walls and internal mixing vanes connected to said inner walls, said internal mixing vanes extending from said inner walls into said container to mix or stir the concrete placed inside said container, said inner walls and said internal mixing vanes having the tendency for the concrete to adhere rigidly to the same when said concrete concrete hardens, and a device for generating microwave energy to generate microwave radiation energy inside said metal container and capable of releasing water molecules from said concrete placed in said container, to weaken the structure of said concrete, facilitating so the rupture of said concrete hardened or rigidly adhered to said inner walls and said mixing vanes, and, therefore, the removal of said concrete from said container

Description

MICROWAVE ENERGY GENERATING DEVICE USED TO FACILITATE THE REMOVAL OF CONCRETE FROM A METAL CONTAINER BACKGROUND OF THE INVENTION The present invention relates to devices used to remove concrete from containers of concrete mixers and a method to remove concrete from such containers.

Containers for concrete mixing are used mainly in what is commonly known as "cement trucks", which are used in the construction industry. Such containers for concrete mixing are usually made of metal, such as steel, and are mounted with a rotating assembly on a truck. The containers have internal mixing vanes to mix or shake the concrete contained therein during the rotation thereof. Such agitation and mixing preserves the consistency of the concrete and inhibits the hardening of the concrete within the container.

In the concrete industry, premixed containers or drums are also known, which are used to premix concrete (usually a mixture of cement, sand, stone, water and hardening agents) with rotating vanes mounted to rotate inside the container . In general, pre-mix containers are also made of steel and have similar volumes to cement truck-type containers. Normally smaller concrete containers are also made of steel and serve, for example, as domestic appliances for paving trails and other similar applications. These smaller containers are also mounted so that they rotate, or have other means for shaking the concrete placed in them.

As can be appreciated, there are significant problems and costs associated with the maintenance of such mixing vessels. For example, if it is left immobile to a container containing concrete for an extended period of time without mixing or shaking the concrete contained therein, the concrete will harden or "solidify". Most of the hardened concrete will adhere to the interior walls of the mixing vessel. The hardening of the concrete within the container can be prevented to a certain extent if the concrete inside the container is continuously stirred until the container is empty and cleaned with water or solvents. However, it is easy to appreciate that it is quite difficult to prevent the concrete from hardening a few times inside the container. In actual practice, it is almost inevitable that a certain amount of hardened concrete will accumulate inside the mixing vessel during its useful life. This accumulation must be removed, or the mixer loses its efficiency and payload capacity. In fact, in some cases, an unusual accumulation of concrete within the mixing vessel results in the need to discard the container. In general, waste is the last resort, since containers of this type are relatively expensive.

Although several methods are currently used to remove hardened concrete from mixing vessels, neither is economical or easy. The most commonly used method of removing concrete is to have a person use a pneumatic hammer, a hammer, and chisel to mechanically break the concrete and then manually remove the concrete fragments from the container. In those cases in which it is necessary to remove hardened concrete from a large mixing container, such as those mounted on cement trucks, it is necessary for the person to climb into the container and mechanically break the hardened concrete while it is inside. In cases where large amounts of concrete must be removed, it is possible to use explosives as a preliminary step to loosen the concrete.

Although concrete can be removed in this way, there are several drawbacks related to it. For exampleit is quite difficult to break it mechanically because of the hardness of hardened concrete, and a good number of man-hours is required when a normal amount of concrete has to be removed. In addition, because of the great diversity of force that needs to be applied to hardened concrete in order to break it (by explosion or by using a suitable tool), it is likely that considerable damage will be caused to the container. For example, the container may be punctured or cracked, resulting in it becoming unusable. At that time, the container will have to be discarded, or repaired at a considerable cost.

The patent literature, such as U.S. Patent Nos. 5,003,144, 3,443,051, 3,430,021, 3,614,163, and 3,601, 448 has proposed the use of microwave radiation energy to assist in cracking concrete or rocky material in an open environment, such as a stony field or on the pavement. However, the use of microwave energy, in this way, has had limited success. Specifically, in order to weaken the chemical structure of the concrete sufficiently to facilitate breakage, it is necessary that the microwaves penetrate deeply into the concrete, and that they be absorbed by water molecules throughout the thickness of the concrete. In an open environment, microwaves should be projected to very localized portions of the concrete, in order to crack it. For example, U.S. Patent No. 3,4430,021 discloses the need to employ a microwave waveguide to direct a microwave beam to a small area of a concrete surface for sufficient time to cause localized cracking. Even through the tedious application of this form of microwave energy, the loss of microwave energy transmission continues to be substantial. As a result, the effectiveness and efficiency of these types of devices is insufficient and commercially deficient.

The present invention arises from extensive experimentation in which the microwave radiation energy was used to remove hardened concrete from the closed environment of a metal container. Experimentation revealed that the generation of microwave energy in a metal container is an extremely effective and efficient way to separate concrete from the interior walls of the container and to make the concrete brittle enough to crack. Because the container is made of metal, it effectively contains not only the concrete but also the microwave radiation energy. The metallic material of the container will continue to reflect the microwaves tuned to the natural resonance frequency of the water molecules until the microwaves hit the water molecules in the concrete and are absorbed by them. The energy absorbed is released as thermal energy and, eventually, the water molecules are released from the concrete in the form of water vapor.

It has been discovered that the operation of the device for generating microwave energy of the present invention for a relatively short period of time (for example, of the order of one hour, depending on the power of the generated microwave energy and the amount of concrete that you want to remove), will cause a sufficient amount of water to be removed from the concrete to cause the concrete to become brittle and crack. In many areas, the concrete is in fact separated from the interior walls of the container. As a result, the force required to separate the concrete is greatly reduced and can be applied relatively easily and quickly, without the possibility of causing damage to the container. For example, a normal hammer or crowbar can be used to dislodge concrete from the walls of the container. Even more importantly, it has been found that after applying the microwave energy for a longer period of time (for example, after a few hours), in fact the hardened concrete weakens enough to break and detach from the wall of the container in the areas where the adhesion forces can no longer support the weight of the concrete. Moreover, it has been found that the application of microwave radiation energy for an even longer period (for example, several hours) will cause the cement to actually explode into fragments. More specifically, as water vapor is released from the concrete, significant amounts of steam accumulate in small pockets within the concrete. As more water vapor is generated, the vapor pressure inside the bags increases. This, combined with the weakened chemical structure of the concrete, eventually causes the hardened concrete to explode. In this way, the hardened concrete can be removed simply by removing the concrete fragments from the metal container, without the need to break it by mechanical means, and without having to put anyone in the confines of the container.

In a prolonged test, it was removed from the container of a cement truck about half (1/2) yard (one yard of concrete is one cubic yard per volume). Approximately one cubic foot of broken material was found and detached from the walls, part of which had exploded. Most of the rest of the concrete had visibly separated from the mixing vanes and the walls of the container, and was sufficiently brittle to lift it off the pallets and walls using a two-pound hammer and a twelve-inch lever. . In most areas, the gap between the concrete and the internal surfaces of the container was large enough to fit the lever. In other areas, you simply had to hit with the hammer so that the concrete would crumble and fall.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an apparatus for mixing concrete that is adapted to facilitate the release of hardened concrete therein. The apparatus includes a metal container and a device for the generation of microwave energy. The metal container is adapted to contain concrete and to allow the concrete in it to mix or agitate, the container having interior walls to which the concrete can adhere when it hardens. The device for the generation of microwave energy generates microwave radiation energy within the metal container and is capable of releasing water molecules from the concrete placed in the container, in order to weaken the chemical structure of the concrete and thus facilitate the rupture of the Hardened concrete and remove it from the container.

Another objective of the present invention is to provide a device for the generation of microwave energy, used to facilitate the detachment of the concrete from the metal container used for mixing the concrete. The device for generating microwave energy includes a rigid base adapted to be mounted on an opening of the metal container, and at least one source of microwave energy generation mounted on the base. The source of microwave energy generation is capable of generating microwave radiation energy within the metal container to release water molecules from the concrete into the metal container in such a way as to weaken the chemical structure of the concrete. Furthermore, it has connected operable circuits, with at least one source of microwave energy generation, with which at least one source of microwave energy generation can be enabled in order to generate microwave energy.

In accordance with the principles of the present invention, another object of the invention is to provide a method for removing hardened concrete from a metal container. The method consists of covering an opening of the metal container; generating microwave radiation energy within the metal container to release water molecules from the hardened concrete that is inside the metal container, so as to weaken the chemical structure of the concrete; uncover the opening of the metal container; and remove the concrete from the metal container.

The preferred embodiment of the present invention will be better understood by reference to the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a schematic view, partly in section, showing a cement truck incorporating a metallic mixing vessel, in accordance with the principles of the present invention.

FIGURE 2 is a partially cutaway view showing the interconnection between the device for generating microwave energy and the metal container of the present invention.

FIGURE 3 is a perspective view, in which some portions were removed in order to better show others, of a protective structure, in accordance with the principles of the present invention.

FIGURE 4 is a perspective view showing a fan for drawing hot air with high water vapor content from the metal mixing vessel, in accordance with the principles of the present invention.

FIGURE 5 is a plan view showing the main opening of the metal mixing vessel of the present invention.

FIGURE 6 is a plan view showing a side of the microwave energy generation device, manufactured in accordance with the principles of the present invention.

FIGURE 7 is a block diagram showing the system used to operate the apparatus of the present invention.

FIGURE 8 is a perspective view showing another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT For convenience, the present invention is shown and described as it applies specifically to the type of metal mixing container with rotating mounting mounted on a cement truck. However, it is understood that the present invention has applications in other types of metal containers for mixing concrete.

In FIGURE 1, a cement truck 10 is generally shown, incorporating a metallic mixing vessel 12 in accordance with the principles of the present invention. The metal container 12 has a front end 14 with a rotary assembly mounted on a rotary apparatus 16 of the truck 10. The rear portion 18 of the container 12 is supported by a mounting of bearings 20 on the truck, which facilitates the rotation of the container by half of the moment of rotation of the apparatus 16.

The container 12 is somewhat tubular, and the rear portion 18 thereof has a main opening, indicated, generally at 22. The opening 22 is defined by an annular projection 24. Although the leading end 14 usually has a similar opening , such opening is closed due to its interconnection with the rotation apparatus 16.

As can be appreciated, the container 12 is adapted to have a concrete slurry, ingredients for dry mixing, or a suspension placed therein by means of the opening 12. As the mixing container 12 rotates by means of the apparatus 16, the internal mixing blades 26 mix or stir the concrete. The mixing blades 26 are welded to the inner surface 28 of the container 12, and extend radially inward of the container 12, in the direction of the axis of rotation "a", indicated by dotted lines.

FIG. 2 shows the interconnection between the metal container 12 and a device for the generation of microwave energy, generally indicated with 30. The device for the generation of microwave energy 30 includes a rigid base 32, made of metallic material, such as aluminum, and has a circular configuration similar to a plate. The base 32 functions as a cover that closes the main opening 22 of the container.

The device for generating microwave energy 30 also includes, at least, a source of microwave energy generation, mounted on the base. In FIGURE 2 the source of microwave energy generation is in the form of a plurality of magnetrons 34. The device for generating microwave energy also includes operable circuits connected to the magnetrons 34, as shown in FIGURE 7, and which will be described in more detail later.

Magnetrons 34 can be obtained commercially, and each uses a power that fluctuates between 0.5 and 1 kilowatts. Preferably, magnetrons of between fifteen to forty-one kilowatts are used, to obtain a total power of 15 to 40 kilowatts. It is understood that the more power used, the less time it takes to make a predetermined amount of water evaporate. It is also understood that a single source of microwave energy generation can be used. For example, it is possible to use a single magnetron of approximately 20 kilowatts. Although a single magnetron with less power can also be used, the amount of time needed to release the required amount of water will be greater than the time considered desirable for the commercial application. We should also note that it is possible to use other types of sources of microwave energy generation, such as tubes to create radiofrequency waves, klystrons, solid-state amplifiers, and others. The source of microwave generation is preferably tuned to the resonance frequency of the water molecule, which is approximately 2450 mHz. However, the excitation of any molecular component, so that the bulk concrete rises to a temperature above the boiling point of water, would be an adequate method to fracture the concrete without using a water resonance frequency.

As shown in FIGURE 2, each of the magnetrons 34 mounted on a rigid base 32, includes an antenna 36, from which the microwave energy is emitted, and a main frame 38. The frame 38 houses the components used to generate microwave energy. As shown, each of the main frames 38 is secured to an outer surface of the rigid base 32 by means of suitable supports 42. The antenna 36 extends through the openings of the rigid base 32, until after the inner surface 44 of the rigid base, and enters the confines of the container. In FIGURE 2, electrical wires and cooling fans for magnetrons are omitted for reasons of clarity.

The annular projection 24 of the container 12 includes an annular peripheral surface 46 of the rigid base 32, when the base 32 is mounted on the opening of the container 12. The fasteners 48 extend through the projection 24 and through the openings 45 of the base 32 in places with circumferential spacing, so as to hold the base 32 to the container 12. Between the protrusion 24 and the annular surface 46 there is an annular sealant 50. Preferably, the sealant 50 is a metal gasket, or a metal resin. In addition to or instead of the sealant 50, it is possible to put an exterior sealant 52. The sealant 52 shown in FIGURE 2 is in the form of a metal strip at the junction between the projection 24 and the rigid base 32. It is advisable to place These sealers to prevent leakage of microwave radiation into the environment.

During a seventeen-hour test, the microwave leakage rate was measured at the interconnection of the annular projection 24 with the annular peripheral surface 46 of the rigid base 32. Metal tape was used as sealant 52. C-shaped jaws were used as fasteners for peripherally clamping the rigid base 32 to the annular projection 24. The leak rate measured was less than 1 milliwatts per square centimeter (1 mW / cm2).

In addition, between the projection 24 of the container and the annular surface 46 of the base, there are contact sensors 56, mounted in locations with circumferential spacing on the annular surface 46. The contact sensors 56 are connected to the circuits shown in FIG. FIGURE 7, and it is possible to operate them to detect if the annular surface 46 is in correct circumferential agreement with the annular projection 24. The contact sensors 56 serve as a precautionary measure to ensure that the microwave energy does not leak into the environment.

FIGS. 2 also shows the handles 58, which are used so that the user can easily place the microwave energy generation device 30 over the opening of the container 12. In this regard, it is preferable that the fasteners 48 be safety pins, which always remain in the rigid base 32, and which can be easily aligned with the openings of the projection 24.

FIGURE 3 shows a protective shield 60 manufactured in accordance with the principles of the present invention. Shield 60 was omitted in FIGURE 2 for convenience. Preferably, the shield 60 should be mounted on the inner surface 44 of the rigid base. The shield 60 has a protective wall 62 mounted directly on the antenna 36, in order to reduce the likelihood that the exploding concrete fragments can impact the antenna 36. The shield 60 is formed of metallic material, and it also serves to give the antenna an impedance balance to have free space. The shield 60 also functions to disperse microwave energy through the aperture 66, after at least a portion of the microwaves is reflected within the confines of the shield 60. Such microwave scattering is advisable since it reduces the time in that the water molecules are reached, and are absorbed by them, of the concrete located in the corners and crevices inside the container.

It can be appreciated that the preferred construction of the device for generating microwave energy is a plate-shaped base. There are also other constructions that offer advantages. For example, the device for generating microwave energy may include an enclosed mounting structure having an opening. Such enclosed mounting structure can have, for example, cylindrical or box-like configuration. A cylindrical mounting structure would include a cuff-shaped part, a closed end, and an open end mounted on the opening of the container 12. In this case, the magnetrons would be mounted on the outside of the cylindrical structure, with the antennas projecting towards within the confines of the enclosed area. With such a configuration, it has a larger mounting surface area, so that it is possible to use more magnetrons. In other words, since the surface area of an enclosed structure is larger than that of the base in a similar way to a plate, it is possible to mount more magnetrons, thus allowing to generate more microwave energy. This causes the release of water molecules from the concrete faster.

In another configuration, such as that shown in Figure 8, the device for microwave generation includes a lid 200 for opening the container. Although the lid may be similar to the rigid base 32, it will not have the magnetrons mounted therein. Instead, the lid 200 will be provided with one or more large openings 202 (in the embodiment of Figure 8 only one opening is shown) passing through, each receiving a metallic flexible tube 204. For example, The tube can be made of corrugated aluminum and have a diameter of approximately two to four feet. The lid provides, at a distance, a source for the generation of microwave energy 206, as could be a plurality of magnetrons. The device for generating microwave energy can also include a mobile box 212 or a box within which the source of microwave energy generation generates the microwave energy. In any case, the metallic flexible tube 204 guides the microwave energy of the distant generation source toward the confines of the container. This tube is peripherally sealed at both ends 208 and 210, so that microwave energy can not escape into the environment. This configuration has many advantages, since the magnetrons are not mounted on the lid, and, as a result, the weight of the unit that is mounted on the container opening is significantly reduced. In addition, circuits and electrical cables that are connected to each magnetron (or to any other microwave generation source) can be hardened more easily. Being the result, that the device can be easier to use for the user.

FIGURE 4 illustrates a ventilation device, which is generally indicated at 70. The ventilation device is also shown in FIGURE 1, mounted on the container 12. The ventilation device includes a fan 72 and a rigid metal plate 74 The plate 74 is held over an opening in the side part of the container 12 by means of suitable fasteners 76. Between the outer surface of the container, near the side opening and the periphery of the plate 74, a similar sealant is used. to the sealant 50 and / or 52 shown in FIGURE 2. Through the plate 74, ventilation holes 78 extend, which allow the fan 72 to draw water vapor from the container as the water is released from the container. hardened concrete by means of the device for the generation of microwave energy. The plate 74 can be mounted on an opening inside the container 12, which is normally provided so that the persons performing the cleaning of the container 12 can be raised to the container 12. When the container 12 is used to mix concrete, a plate similar to the plate 74, but without ventilation holes, covers the side opening of the container.

It is preferable that the ventilation holes 78 of the plate 74 be small enough, so as not to allow the microwaves to escape through them. For example, it is preferable that such openings have a diameter less than% "for microwave frequencies of 2450 mHz, since the microwave wavelength of this frequency is sufficient so that they do not pass through holes of this size.

The contact sensors 75 are preferably placed at spaced locations between the peripheral interconnection of the inner surface of the plate 74 and the outer surface of the container 12. The contact sensors 75 are connected to the circuits shown in Figure 7, and can be operated to give the proper indication when the correct peripheral contact between the plate 74 and the outer surface of the container 12 is not achieved. Contact sensors 75 are provided to alert the user to possible microwave leakage between the plate 74 and the container 12.

FIGURE 5 is a plan view showing the inner confines of the container 12, viewed through the opening 22. As shown, the peripheral protrusion 24 has a plurality of openings 80, which serve to receive the fasteners 48 that are show in FIGURE 2. As can also be seen in FIGURE 5, the vanes 26 extend radially inward toward the axis of rotation of the container, and end at a predetermined distance "r" thereof. This distance "r" is shown by dotted lines in FIGURE 5, and represents the radius of a circle generally defined by the inner edges of the blades 26. The dotted line "D" represents the diameter of this circle.

FIGURE 6 is a plan view of the device for the generation of microwave energy 30, showing the external surface 40, and the main frames 38. The cables that connect the magnetrons electrically with the appropriate circuits, nor the fans are not shown Cooling by means of pressurized air to cool the magnetrons. In FIGURE 6, the antennas 36 of each of the magnetrons 34 are represented by circular dotted lines. As also shown in FIGURE 6, the vent holes 84 are positioned at spaced locations along the rigid base 32. These vent holes allow outside air to enter the confines of the container 12 as the air with high water vapor content is expelled through the ventilation holes 78 of the plate 74. The ventilation holes 84 provide cross ventilation through the container, and accelerate the speed at which the water molecules are removed from the container by the container. fan 72. It is preferable that the vent holes 84 of the rigid plate 32 be small enough to not allow the microwaves to escape through them. For example, it is preferable that such openings have a diameter less than% ", as described hereinabove with respect to the openings 78 of the plate 74.

In FIGURE 6 it can also be discerned that it is preferable that most of the magnetrons 34 are concentrated towards the center of the rigid base 32, so that the antennas 36 are disposed within the radius "r" from the center of the base. As indicated above, the circle formed by the inner edges of the vanes 26, defines the radius "r", as shown in FIGURE 5. This position of the magnetrons 34 decreases the time necessary for the dispersion of the microwaves towards the posterior portion of the container, in order to facilitate the release of water molecules from the concrete contained therein.

FIGURE 7 shows the circuits that are part of the device for generating microwave energy of the present invention. The circuits include an AC voltage source 240 of 60 Hz 90. The voltage source 90 provides power for the entire apparatus, including fan ventilation 72, high voltage filament transformer 92, magnetrons 34, contact sensors 56, contact sensors 75, a fan 94 for cooling transformer 92, and a fan 93 for cooling of the magnetrons. Thermal circuit breakers 95 are used to protect magnetrons and transformers. The circuits also include a capacitor 96 and a diode 98. The diode, the capacitor and the high-voltage transformer serve to provide electrical energy to the magnetrons 34, which convert the electrical energy into microwave energy. There is an on / off switch 102 which is connected to a relay 104, and which controls the operation of the device for the generation of microwave energy 30. Indicator lights 106 are provided to indicate the correct operation and / or the condition of the magnetrons 34, of the transformers 92, of the contact sensors 56, and of the contact sensor 75. For example, such indicator lights 106 can indicate whether energy is being supplied to each magnetron, and if each of the contact sensors is making contact with the surface with which you have to make contact. It can also be appreciated that although only one on / off switch 102 is provided, it is possible to put a separate switch for each magnetron. This can be beneficial, for example, when the same device for generating microwave energy of the present invention is to be used in sequence in conjunction with several containers of different sizes. It may be preferable to use more microwave radiation energy with a larger container than with a smaller container.

Regarding the way in which the microwave energy generation device is attached to the container, other bolts than those described may be used. For example, it is possible to use the aforementioned C-shaped jaws to hold the outer peripheral portion of the rigid base 32 to the projection 24. The use of this type of jaw can facilitate the ability to adapt the device for power generation of microwaves to the containers that have projections 24 with different diameters.

Since the mixing vessels normally have a rectangular-shaped main opening, which is generally larger than the opening of a cement truck container, the device for microwave generation can be easily adapted by adjusting the size and shape of the container. shape of the rigid base according to the size and shape of the opening on which it is to be mounted. The same applies when the device for microwave generation is to be used together with a smaller mixing vessel.

Although the invention has been illustrated and described in detail in the drawings and the foregoing description, however this should be considered as illustrative only and not as limiting. It should be understood that the preferred embodiment was shown and described, and that all changes and modifications implicit in the spirit and scope of the appended claims should be protected.

Claims (30)

Having described the invention, it is considered a novelty and therefore the content is claimed in the following: CLAIMS

1. A combination of a concrete mixing container and a device for removing hardened concrete from it, which includes: a metal container adapted to contain concrete, said metal container having inner walls and internal mixing vanes connected to said inner walls, said internal mixing vanes extending from said inner walls into said container to mix or stir the concrete placed therein. of said container, said inner walls and said internal mixing vanes having the tendency for the concrete to adhere rigidly thereto when said concrete hardens; Y a device for generating microwave energy to generate microwave radiation energy inside said metal container and capable of releasing water molecules from said concrete placed in said container, to weaken the chemical structure of said concrete, thus facilitating the rupture of said concrete hardened or rigidly adhered to said inner walls and said mixing vanes, and, therefore, the removal of said concrete from said container.

2. The combination, according to claim 1, wherein said microwave energy generating device includes: a rigid base to be mounted on an opening in said metal container; at least one source of microwave energy generation mounted on said base; Y operable circuits connected with at least one source of microwave energy generation, so that at least one source of microwave energy generation generates microwave energy.

3. The combination, according to claim 2, wherein at least one source of microwave energy generation includes at least one magnetron mounted on said rigid base.

4. The combination, according to claim 3, wherein each said magnetron includes an antenna from which said microwave energy is emitted, and which further includes a protective shield to protect said antenna from the concrete fragments, inside said container , that could be projected towards said antenna as a result of the weakening of the chemical structure of said concrete.

5. The combination according to claim 4, wherein said protective shield is formed of metal and serves to disperse said microwave energy as it is emitted by said antenna.

6. The combination, according to claim 3, wherein said rigid base has a plate-like configuration and is formed of a metallic material, said base having an interior surface facing inwardly of the confines of said container, and a opposite surface facing away from said container when said base is mounted on the opening of said container, and wherein each of said magnetrons includes a main frame mounted on the opposite surface of said base, and an antenna extending from said main frame through a hole in said base so as to project up after said inner surface inside said container when said rigid base is mounted in said container.

7. The combination, according to claim 2, wherein said metal container includes an annular projection surrounding said opening of the container, and wherein said rigid base has an annular surface constructed and positioned to settle on said projection when said base it is mounted on said opening.

8. The combination, according to claim 7, further comprising fasteners for securing said rigid base to said projection of said container, with said annular surface of said rigid base disposed in contact with said projection.

9. The combination, according to claim 8, further comprising a sealant disposed at the junction between said annular surface of said rigid base and said projection of said container, to prevent the microwave energy from escaping from said container through said container. Union.

10. The combination, according to claim 9, wherein said sealant includes at least one metallic resin and a metal joint disposed between said annular surface and said projection.

11. The combination, according to claim 9, wherein said sealant includes a metal belt.

12. The combination, according to claim 9, further comprising contact sensors arranged in circumferentially spaced positions on said annular surface, said contact sensors being operable to detect if said annular surface is circumferentially attached to said annular projection.

13. The combination, according to claim 9, wherein said annular surface is disposed at an outer periphery of said rigid base.

14. The combination, according to claim 6, further comprising, at least, a handle mounted on said opposite surface.

15. The combination, according to claim 2, further comprising at least one vent opening in at least one of said containers and said rigid base, and a fan for expelling said water molecules released from said concrete through when less an opening, to expel them from said container.

16. The combination, according to claim 15, further including, at least, a cross ventilation opening disposed in at least one of said containers and said rigid base in a spaced apart position of at least one ventilation opening to provide cross ventilation, facilitating that said fan expels said water molecules from said container through at least one ventilation opening.

17. The combination according to claim 16, wherein at least one opening the ventilation and at least one cross ventilation opening have a diameter smaller than the diameter that would allow the microwave energy to escape from said container through the openings

18. The combination, according to claim 17, wherein said diameter of said openings is less than% ".

19. The combination according to claim 15, wherein said container includes a removable panel having at least one vent opening disposed therein, and wherein said fan is mounted on said removable panel of said container for removing said water molecules, through at least one opening of said removable panel, out of said container.

20. The combination according to claim 19, wherein a sealant is disposed between a peripheral portion of said removable panel and the outer surface of said container, to prevent the microwave energy from escaping from said container.

21. The combination according to claim 3, wherein said container is adapted to be mounted with a rotating assembly on a truck, wherein a rotation axis of said container generally passes through a central portion of the container. said opening of said container, and wherein said internal mixing blades extend radially inward, starting from said inner walls toward said axis.

22. The combination according to claim 21, wherein said mixing vanes end radially on an inner edge disposed at a predetermined distance from said axis, at least one magnetron mounted on said rigid base being located at a distance from said an axis that is generally less than or equal to said predetermined distance from said axis, when said base is mounted on said opening of said container, so that said microwave energy can be directed through said container without said vanes cause significant interference.

23. The combination, according to claim 21, wherein said container includes a rear opening disposed in a position opposite said opening on which said rigid base is mounted, said rear opening being adapted to be closed by a part of said truck on which said container is mounted.

24. A microwave energy generation device used to facilitate the removal of concrete from a metal mixing vessel having an opening, said microwave energy generating device including: a lid having an outer periphery larger than the opening of the metal container for mixing, so as to allow the lid to close said opening of said container, said lid having at least one opening through it; A metallic box disposed at a distance from said lid; at least one source of microwave energy generation contained within said metal box remote from said cover and adapted to generate microwave radiation energy within the metal box; at least one conduit for communication between said metal box distant from said lid and at least one opening of said lid, for transmitting the microwave radiation energy generated by at least one source of microwave energy generation through when less an opening of said lid and inside said metal container, to release water molecules from the hardened concrete within the metal container and thus weaken the chemical structure of said hardened concrete; Y operable circuits connected with at least one source of microwave energy generation, to allow at least one source of microwave energy generation to generate microwave energy.

25. A microwave energy generating device according to claim 24, wherein said lid is in the form of a metal plate, and wherein at least one conduit is made of aluminum.

26. A method to remove hardened concrete from a metal container used for concrete mixing, which consists of: covering an opening of said metal container; generating microwave radiation energy within said metal container to release water molecules from said hardened concrete in said metal container, thereby weakening the chemical structure of said hardened concrete; uncovering said opening of said metal container; Y removing said hardened concrete from said metal container.

27. A method according to claim 16, further including the generation of sufficient microwave energy within said container to cause said hardened concrete to weaken to the extent that it fractures during the generation of said microwave energy.

28. A method according to claim 26, further including the mechanical breaking of said weakened concrete after uncapping said opening from the metal container.

29. A method according to claim 26, wherein said hardened concrete is initially adhered to the interior walls of said container, and furthermore consists of: separating said hardened concrete from said interior walls as a result of the generation of said microwave radiation energy within the metal container.

30. A method to use and clean a metal container used to mix concrete in a cement truck, which consists of: using said metal container to mix at least one batch of concrete slurry by rotating said metal container and causing the mixing vanes of said metal container to agitate said concrete slurry, adhering at least a portion of said slurry concrete to the inner walls and said mixing vanes of said metal container, and solidifying said inner walls and said mixing vanes; closing an opening of said metal container after a selected amount of said concrete slurry has solidified in said mixing vanes of said metal container; generating microwave radiation energy within said metal container to release water molecules from said solidified concrete in said metal container, thereby weakening the chemical structure of said concrete and causing at least a portion of said solidified concrete to separate from said concrete. said mixing blades; uncovering said opening of said metal container; Y removing, through said opening, at least a portion of said solidified concrete that has been separated from said mixing vanes of said metal container.