DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0029] Embodiments of the present invention will be explained below with reference to the drawings, wherein like members are designated by like reference characters.

[0030] As shown in FIG. 1, a combustion system S1 for burning water-in-oil emulsion using an electromagnetic wave heating includes an emulsifying unit constituted of a fixed quantity mixer system 10 and a static mixer 20 with no moving parts, and a burner 30 as a combustion device.

[0031] The mixer system 10 includes an agitator unit 14, and three tanks of a water tank 11, a fuel tank 12 and an emulsifying agent tank 13 connected to the agitator unit 14 through lines 11c, 12c and 13c, respectively. In the respective water tank 11, fuel tank 12 and emulsifying agent tank 13, level sensors 11a, 12a and 13a are provided to monitor levels of the respective water, fuel, emulsifying agent therein and to alert shortages thereof. On the lines 11c, 12c and 13c from the respective water tank 11, fuel tank 12, emulsifying agent tank 13 to the agitator unit 14, control valves V1, V2 and V3 and feedback systems 11b, 12b and 13b associated with the respective valves V1, V2 and V3 are provided to automatically control flow rates of the water, fuel and emulsifying agent to be supplied to the agitator unit 14. Thus, in the mixer system 10, the water, fuel and emulsifying agent are metered/weighed and mixed together at a preset water/fuel ratio to be fed to the static mixer 20.

[0032] The mixed water and fuel is pressurized and fed to the static mixer 20 by a feed pump 15. On a line 15a from the feed pump 15 to the static mixer 20, a pressure regulator valve V4 with a pressure gauge 10 is provided, by which feed pressure of the mixed water and fuel is adjustable to a desired level.

[0033] The static mixer 20 is constituted of a housing 21 and a plurality of honeycomb labyrinth units 22 stacked in multiple stages in the housing 21. The mixed water and fuel is forced into the housing 21 through an inlet 21a of the static mixer 20, to pass through between the honeycomb labyrinth units 22 where the water and fuel is repeatedly sheared to split and converged and emulsified into water-in-oil emulsion in which water is dispersed in a oil phase as droplets in the range of sub-microns in diameter, and discharged from an outlet 21b of the static mixer 20.

[0034] The produced water-in-oil emulsion is once stored in a depressurization tank 17 under atmospheric pressure, and then fed to the burner 30 by a fuel pump 18. On a line 18a from the fuel pump 18 to the burner 30, a throttle valve V5 is provided to regulate the feeding rate of the emulsion fuel to the burner 30.

[0035] The burner 30 is constituted of a pre-loading chamber 31, a combustion chamber 32, around which a high frequency coil 34 of a water-cooled copper tube is wound, an atomizer nozzle 33 through which the water-in-oil emulsion pre-loaded at an appropriate level is sprayed into the combustion chamber 32 to produce a spray of droplets of the emulsion, and a high frequency AC power supply 35. The burner 30 serves as a combustion device which heats the spray of water-in-oil emulsion in the chamber 32 by electromagnetic wave heating and burns the heated spray thereof.

[0036] The description will be made to the detail of the respective components of the combustion system S1.

[0037] The housing 21 of the static mixer 20 is formed in a cylindrical shape, as shown in FIG. 2, having flanges 21f at both ends thereof. A pair of end plates 23 are provided to close the openings at both ends of the housing 21, each of which are fixed to the flanges 21f by bolts b1 penetrating therethrough. The inlet 2la through which the mixed water and fuel is introduced into the mixer 20 is formed on one of the end plates 23, and the outlet 21b through which the water-in-oil emulsion is discharged is formed on the other endplate 23. Inside the housing 21 next to the respective end plates 23, a pair of pressure blocks 24 are provided axially displaceable to approach each other. On both of the end plates 23, a plurality of pressure bolts b2 are provided therethrough with the tip thereof inside the housing 21 in contact with the pressure blocks 24, whereby, by screwing the pressure bolts b2 in, the pair of pressure blocks 24 set an appropriate pressure on the stacked honeycomb labyrinth units 22 sandwiched therebetween.

[0038] The honeycomb labyrinth unit 22 is constituted of a diverging section 22A and a converging section 22B arranged parallel to each other as shown in FIG. 3. As shown in FIG. 4, the diverging section 22A is constituted of an outer honeycomb labyrinth disk 220A provided on its central part with an inlet 220E through which the mixed water and fuel is introduced into the unit 22, and an inner honeycomb labyrinth disk 220B with no opening such as the inlet 220E provided thereon. Similarly to the diverging section 22A, the converging section 22B is constituted of an outer honeycomb labyrinth disk 221A provided on its central part with an outlet 221D through which the oil-in-water emulsion is discharged out of the unit 22, and an inner honeycomb labyrinth disk 221B with no opening such as the outlet 221D. The outer and inner honeycomb labyrinth disks 220A and 220B are formed to have, on their surfaces opposite to each other, ribs 220K and 220L, respectively, each of which is continuous in a hexagonal mesh-like configuration, forming a plurality of hexagonal holes 220H thereon arranged in a honeycomb pattern. The outer and inner honeycomb labyrinth disks 220A and 220B are mated in a manner that the respective ribs 220K, 220L are positioned not to be in alignment with each other and the respective hexagonal holes 220H on the disks 220A and 220B off to the side of one another. Specifically, the disks 220A and 220B are mated in a manner that each of the hexagonal holes 220H on one of the disks 220A and 220B is arranged so that a meeting point of the rib 220K or 220L between three of the holes 220H is located at a center point of the opposing hexagonal hole 220H on the other disk. In addition, the inner honeycomb labyrinth disk 220B is formed to have three positioning projections 220F on its rim part with equally provided spaces in a circumferential direction, which ensure the positions of the hexagonal holes 220H when the disks 220A and 220B are mated. Similarly to the disks 220A and 220B, the outer and inner honeycomb labyrinth disks 221A and 221B of the converging section 22B are formed to have, on their surfaces opposite to each other, ribs 221K and 221L, respectively, each of which is continuous in a hexagonal mesh-like configuration, forming a plurality of hexagonal holes 220H thereon arranged in a honeycomb pattern. The outer and inner honeycomb labyrinth disks 221A and 221B are mated in a manner that the respective ribs 221K, 221L are positioned not to be in alignment with each other and the respective hexagonal holes 220H on the disks 221A and 221B off to the side of one another. In addition, the inner honeycomb labyrinth disk 221B is formed to have three positioning projections 221F on its rim part with equally provided spaces in a circumferential direction, which ensure the positions of the hexagonal holes 220H when the disks 221A and 221B are mated. Thus, the mated honeycomb labyrinth disks 220A and 220B cooperate to define a diverging flow path therebetween for the water and fuel or water-in-oil emulsion introduced through the inlet 220E. The mated honeycomb labyrinth disks 221A and 221B cooperate to define a converging flow path therebetween for the emulsion to be discharged through the outlet 221D.

[0039] The water and fuel or water-in-oil emulsion introduced through the inlet 220E of the honeycomb labyrinth unit 22 flows through the diverging flow path in the diverging section 22A, out from a gap between the disks 220A and 220B on outer periphery of the diverging section 22A, and then flows into a gap between the disks 221A and 221B on outer periphery of the converging section 22B, through the converging flow path in the converging section 22B, out of the outlet 221D. In the diverging or converging flow path, the water and fuel or the emulsion are forced to be repeatedly sheared and split, flowing from one of the holes 220H on one disk to a couple of opposing holes 220H on the other disk. In the honeycomb labyrinth units 22 stacked in multiple stages, the water and fuel repeatedly flows through such paths, whereby the static mixer 20 can produce the water-in-oil emulsion with an enhanced degree of dispersion in proportion to the number of the honeycomb labyrinth units 22 therein.

[0040] As shown in FIG. 1, the water-in-oil emulsion from the static mixer 20 is sent to the pre-loading chamber 31 of the burner 30 and is atomized through the atomizer nozzle 33 into the combustion chamber 32 to be heated. In the first embodiment, the spray of the emulsion is heated principally by radiation from or partially by convective heat transfer through contact with the body of the heating chamber 32 that is heated by an induction heating with the high frequency coil 34. The heating chamber 32 may be made of a material such as a conductive material having a high melting point with appropriate electrical resistance. As shown in FIG. 5, the atomized water-in-oil emulsion in the combustion chamber 32 is a spray of water droplets X1, oil droplets Y1, and droplets Z1 of oil containing water dispersed in the oil phase. When the spray is heated, due to the lower boiling point of water than that of the oil, explosive vaporizations or micro-explosions first occur on the water droplets X1 or the internal water droplets in the droplets Z1. The vaporizations of the water droplets X1 cause rapid expansion of the oil droplets Y1 or the surrounding oil of the droplets Z1, fragmenting the oil into smaller droplets. As a result, as shown in FIG. 6, uniform oil and water mixture gas XY of fine particles is formed, whereby the water molecule can transit to its critical state upon igniting. That is, an atmosphere of the induction-heating inside the combustion chamber 32 lowers a temperature critical point and a pressure critical point at which an extremely critical oxidizing reaction occurs in water molecule.

[0041] With a second embodiment of the present invention shown in FIG. 6, the water-in-oil emulsion is delivered through the pre-loading chamber 31 of the burner 30, atomized through the atomizer nozzle 33 into a combustion chamber 40, and then radiated in the combustion chamber 40 with microwaves guided through a wave-guide tube 41 from a microwave generator 42 (such as a magnetron) to be subjected to electromagnetic excitation heating (microwave heating). Other members, components and parts, functions and operations thereof in the second embodiment are similar to those of the first embodiment, with like members designated by the same reference numerals.

[0042] In the foregoing description, an emulsifying agent is not necessarily required for an application in which a water-in-oil emulsion is used within a short period of time after being discharged from the static mixer 20. This is because the static mixer 20 is capable of producing a stable emulsion with a high degree of dispersion, oil and water of which is inseparable within the short period of time. Also, the frequency and voltage of the high frequency alternating current to be applied to the high frequency coil 34 may be adjusted depending upon a water/oil ratio of the emulsion, size or material of the combustion chamber 32.

[0043] As set forth above, the electromagnetic wave heating type combustion system of the present invention is possible to effectively combust water-in-oil emulsion, by the provision of an atmosphere of electromagnetic wave heating generated by the high frequency coil, while lowering the temperature critical point and the pressure critical point at which extremely critical oxidizing reaction occurs in water molecule. The static mixer can emulsify water and fuel into water-in-oil emulsion at a high degree of dispersion, enabling water-in-oil emulsion with a high water/oil ratio to be stably combusted, eliminating the need of providing a large-sized vaporizing/heating chamber, which is preheated at a high temperature using normal fuel, for a small-sized practical burner.

[0044] The preferred embodiments described herein are illustrative and not restrictive, and the invention may be practiced or embodied in other ways without departing from the spirit or essential character thereof. The scope of the invention being indicated by the claims, and all variations which come within the meaning of claims are intended to be embraced herein.

[0045] The present disclosure relates to subject matter contained in Japanese Patent Application No. 2003-023712, filed on Jan. 31, 2003, the disclosure of which is expressly incorporated herein by reference in its entirety.