JP2013037882A - Microwave device and circulation pipe thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure uniform and efficient processing by increasing the flow rate of a processed liquid, in a microwave device using a single mode cavity resonator.SOLUTION: The circulation pipe 60 houses an obstacle means 63 having a dielectric constant different from that of the processed liquid and disturbing the flow thereof, and is installed in the irradiation chamber of a cavity resonator while aligning the axis with the direction of an electric field generated in the irradiation chamber. When the circulation pipe is installed in the irradiation chamber of a microwave device, the electric field distribution is not uniform in the circulation pipe for feeding the processed liquid, and since the microwaves being absorbed into the processed liquid are reduced, lowering of Q is minimized, and since detuning is less likely to occur, flow rate of the processed liquid can be increased.

Description

  Techniques relating to an apparatus for performing treatment such as heating and chemical reaction promotion on a substance by irradiating microwaves are disclosed below.

  In recent years, it has been found that microwaves promote chemical reactions of substances, and in fields such as biochemistry, interest in chemical reaction devices using microwaves is increasing. As such microwave devices for promoting chemical reaction and heating, a so-called microwave-type batch-type device in which a liquid to be processed is accommodated and processed in a test tube or a flask is currently mainstream. However, since the processing capability is limited in the batch type, a flow type apparatus that forms a flow path and irradiates microwaves while flowing a liquid to be processed in the flow path is being studied (see Patent Document 1). .

  The microwave device of Patent Document 1 has a flow path disposed in a rectangular waveguide. However, the use of a cavity resonator increases the absorption efficiency of the microwave, resulting in better processing efficiency. In particular, a device having a flow path formed in a single-mode cavity resonator has excellent reaction reproducibility, and the electromagnetic field generated in the cavity resonator at the time of resonance can reduce the processing time. it can. However, in the case of a microwave device using a cavity resonator, it is considered difficult to tune the cavity resonator and the microwave.

JP 2006-272055 A

  In a single-mode cavity resonator, the strong electromagnetic field is a disaster, and it can be said that the microwave absorbed by the liquid to be treated is too large, which makes tuning difficult. That is, the energy per unit time absorbed by the liquid to be treated is too large compared to the microwave energy stored in the cavity resonator, and the resonance frequency defined by the ratio of these two quantities multiplied by the angular frequency. “Q” becomes low. When Q is lowered, not only the characteristics as a resonator are lost, but also tuning itself with respect to the resonance frequency necessary for maintaining resonance becomes difficult.

  Currently, the cross-sectional area of the flow path is made as small as possible so that the volume of the liquid to be processed existing in the cavity resonator is as small as possible compared to the cavity volume, and the unit to be absorbed by the liquid to be processed Efforts can be made by reducing energy per hour. That is, the diameter of the flow path, which is generally a cylindrical tube, is made as small as possible to suppress the amount of liquid to be processed flowing through the flow path per time, that is, the volume of the liquid to be processed existing in the cavity resonator. That's what it means. In order to keep Q at an appropriate value by this countermeasure, in the case of a cavity resonator operating at a current microwave frequency of 2,450 MHz, the flow path should be narrow with a diameter of 1.0 mm or less. I must. In this case, it is hard to say that there is sufficient processing capacity for practical use.

  In view of such a background, the present invention relates to a microwave device using a single-mode cavity resonator, and proposes a technique for increasing the flow rate of the liquid to be processed so as to enable uniform and efficient processing.

  The present invention proposes a single-mode cavity resonator having a rectangular columnar cavity or a cylindrical cavity, and the irradiation along the axis with respect to the direction of the electric field generated in the irradiation chamber. A circulation pipe installed in the chamber, and a failure means that has a dielectric constant different from that of the liquid to be treated flowing through the circulation pipe and is contained in the circulation pipe and disturbs the flow of the liquid to be treated. This is a microwave device.

  That is, a flow pipe that can be used in a microwave device including an irradiation chamber having a rectangular columnar cavity or a cylindrical cavity, and has a dielectric constant different from that of the liquid to be treated flowing through the flow pipe. Proposed is a flow pipe that accommodates obstruction means for disturbing the flow of the liquid to be treated and is installed in the irradiation chamber along an axis with respect to the direction of the electric field generated in the irradiation chamber.

  The distribution pipe according to the above proposal has a dielectric constant different from the dielectric constant of the liquid to be treated, and contains obstacle means for disturbing the flow of the liquid to be treated. When this flow tube is installed in the irradiation chamber (resonance cavity) of the microwave device, the electric field distribution is not uniform in the flow tube through which the liquid to be treated flows, and the effect of reducing the average electric field strength is produced. The absorption of microwaves by the liquid to be treated is suppressed. As a result, even if the diameter of the flow pipe is made larger than before and the volume of the liquid to be processed existing in the irradiation chamber is increased, the reduction rate of the resonance frequency is suppressed. It is easy to fit within the ISM (Industry-Science-Medical) band, and further, the Q is prevented from being lowered to facilitate tuning, and the volume of the liquid to be processed in the irradiation chamber is increased to improve the processing efficiency. It becomes possible.

The block diagram which shows the example of whole structure of a microwave apparatus. The 1st example of a cavity resonator is shown, (A) is the front view seen from the same side as FIG. 1, (B) is a left view, (C) is a top view. The 2nd example of a cavity resonator is shown, (A) is the front view seen from the same side as FIG. 1, (B) is a left view, (C) is a top view. Sectional drawing of the cavity resonator which shows 1st Embodiment of a flow pipe. The enlarged view explaining the distribution pipe which concerns on 1st Embodiment. The figure which shows the electric field simulation result in the flow pipe which put the obstruction means. The figure which shows the experimental result of the flow pipe which concerns on 1st Embodiment. The figure equivalent to FIG. 5 which shows 2nd Embodiment of a distribution pipe. The figure equivalent to FIG. 5 which shows 3rd Embodiment of a distribution pipe. Sectional drawing of the cavity resonator which shows 4th Embodiment of a flow pipe. Sectional drawing of the cavity resonator which shows 5th Embodiment of a flow pipe. The figure which shows the circumferential direction electric field change simulation result around a central axis regarding the electric field in the cavity resonator shown in FIG. The figure which shows an example of the flow mechanism which flows a to-be-processed liquid into a flow pipe.

  First, FIG. 1 shows an example of the overall configuration of the microwave device. The illustrated microwave device has a configuration in which a waveguide 20 and a microwave generator 30 are assembled to a cavity resonator 10 and controlled by a controller 40 such as a personal computer.

  The microwave generator 30 includes a variable frequency oscillator 31 and a variable amplifier 32. A variable frequency oscillator 31 outputs a microwave having a variable frequency (for example, 2.4 GHz to 2.5 GHz), and a variable amplifier 32 variably amplifies the power of the microwave. The frequency of the variable frequency oscillator 31 and the power of the variable amplifier 32 are controlled according to the controller 40. The microwave output from the microwave generator 30 is sent to the coaxial waveguide converter 21 via an isolator 33, a directional coupler 34, and the like connected by a coaxial cable. The microwave guided by the waveguide 20 through the coaxial waveguide converter 21 passes through the irises 11 and 11 ′ shown in FIG. 2 and FIG. 3, and passes through the resonance cavity formed in the cavity resonator 10. It is introduced into the irradiation chamber 12, 12 ′.

  When microwaves are introduced into the irradiation chambers 12 and 12 ', the strength of the electric field or magnetic field is detected by two antennas 50 (for example, loop-shaped antennas) spaced apart from each other in the direction of the central axis, and the detection result is a controller. 40. For example, one of the two antenna outputs is used for observation and the other is used for control. However, the installation of two antennas is not essential. As will be described later, the controller 40 can also receive the result of measuring the temperature of the liquid to be treated. The controller 40 controls the microwave generator 30 according to these inputs.

  When an operation for starting microwave irradiation is performed, the controller 40 starts microwave output by the microwave generator 30 and executes a frequency control process. The frequency control process is control for tuning the frequency of the microwave output from the microwave generator 30 to the resonance frequency of the irradiation chambers 12 and 12 ′ in accordance with the detection result by the antenna 50. The controller 40 that executes the frequency control process determines the tuning frequency from the detection result of the antenna 50 while sweeping the frequency of the variable frequency oscillator 31. At this time, the controller 40 may set the power from the variable amplifier 32 to a minimum weak power within a range that does not interfere with detection by the antenna 50. By weakening the output power of the microwave introduced into the irradiation chambers 12 and 12 ′, it is possible to suppress the influence that can be given to the liquid to be processed during the execution of the frequency control process.

  The weak power in this case is set to the following value, for example. Since the variable amplifier 32 is generally configured by a combination of a variable attenuation unit and an amplification unit, the output power of the variable amplifier 32 when the attenuation rate of the variable attenuation unit is set to the maximum value (99% or the like) is weak. It can be power. As an example, the weak power can be 100 mW or less.

  The controller 40 executes a power control process for controlling the power of the microwave following the tuning by the frequency control process. The power control process is a process of controlling the microwave power by controlling the variable amplifier 32 of the microwave generator 30 according to the conditions set by the operator before the start of microwave irradiation. In the power control process, the controller 40 adjusts the power of the microwave output from the microwave generator 30 according to the detection result by the antenna 50 (or the temperature measurement result of the liquid to be processed). If accuracy is desired, both the detection result of the antenna 50 and the temperature measurement result should be used.

  For example, the controller 40 first executes the frequency control process at the start of microwave irradiation, then executes the power control process, interrupts the frequency control process at regular intervals during execution of the power control process, and executes it. To do. In the frequency control process, the controller 40 controls the variable amplifier 3b to output the microwave with the above-described weak power, and controls the variable frequency oscillator 31 to tune the frequency.

  A first example of the cavity resonator 10 in the microwave device as described above is shown in FIG.

  In the cavity resonator 10 according to the first example, two opposed bottom walls 13 and 14 shown in the upper and lower sides are square in the figure, and rectangular side walls are provided on each side of the square bottom walls 13 and 14. It is configured by fixing 15, 16, 17, 18 with bolts or the like. In this example, of the four side walls 15, 16, 17, 18, one side wall 15 shown in FIG. 2B is connected to the flange 22 of the waveguide 20 to connect the waveguide 20. The area is expanded correspondingly, and the expanded portion protrudes from the ends of the bottom walls 13 and 14.

  In the rectangular parallelepiped cavity resonator 10 formed by assembling the bottom walls 13, 14 and the side walls 15, 16, 17, 18, the square bottom and side walls 15, 16, The irradiation chamber 12 having a rectangular columnar shape (regular quadrangular columnar shape) having rectangular side surfaces 17 and 18 is formed. The iris 11 for introducing the microwave into the irradiation chamber 12 is opened as a rectangular opening at the central portion of the side wall 15 that forms the side surface of the irradiation chamber. The iris 11 of the first example is rectangular and its long axis extends parallel to the center of the irradiation chamber bottom, that is, in this example, the center axis C connecting the centers of the bottom walls 13 and 14.

  The microwave introduced from the waveguide 20 into the irradiation chamber 12 of the quadrangular columnar cavity through the iris 11 serving as a coupling slit generates a single mode electric field along the direction of the central axis C at the time of resonance. Strictly speaking, if nothing is contained in the cavity resonator 10, the electromagnetic field of the TM110 mode is excited. Therefore, an electromagnetic field having a distribution roughly following the electromagnetic field distribution of the TM110 mode is generated in the irradiation chamber 12.

  Regarding the irradiation chamber 12, let L be the length of one side of the square formed by its bottom surface. It should be noted that a dimensional difference of about ± several percent with respect to L can be allowed. In the case of a microwave frequency of 2450 MHz, which is general for heating and the like, L when there is nothing in the irradiation chamber 12 is 86.5 mm. However, in reality, since the liquid to be treated which is a dielectric exists in the irradiation chamber 12, the resonance frequency of the irradiation chamber 12 is lowered under the influence. Therefore, L in the irradiation chamber 12 is designed to be smaller than the dimension when empty, and should be a value that can resonate when there is a liquid to be processed in the irradiation chamber 12 and the resonance frequency is lowered. Further, when L is set longer, in addition to the planned resonance in the single mode, a problem such as mode competition that resonates in a higher-order mode at a nearby frequency may occur. As a result of repeated trials such as simulation in consideration of these conditions, the length L of one side of the square formed in the bottom surface of the irradiation chamber 12 is designed to be 75% or less of the wavelength of the microwave introduced into the irradiation chamber 12. Is suitable. In addition, since the electric field is generated in the direction of the central axis C, the length H of the long side of the rectangle formed by each side in the irradiation chamber 12 (height of the regular quadrangular prism) may be designed as appropriate. .

  The iris 11 that couples the microwave from the waveguide 20 to the cavity resonator 10 is involved in setting the electromagnetic field excited in the irradiation chamber 12 only to the planned single mode (TM110 or TM010 described later). . In the iris 11 shown in FIG. 2B, a microwave current flows in the direction of the central axis C on the long side (side edge), and the magnetic field surrounding the central axis C is parallel to the central axis C due to the current. Electric field is generated. An optimum value of the width of the iris 11 (direction orthogonal to the central axis C) can be obtained by simulation and experiment. Although the cavity resonator 10 may generate the TE mode, an unexpected phenomenon may occur when the TE mode occurs, so the TE mode needs to be suppressed as much as possible. In the relationship between the waveguide 20 and the iris 11 in FIG. 2, as long as the structural symmetry with respect to the central axis C is maintained, there is no electric field in the horizontal direction in the figure, so that the TE mode can be suppressed. is there.

FIG. 3 shows a second example of the cavity resonator 10.
The cavity resonator 10 of the second example has a cylindrical cavity irradiation chamber 12 ′, and the diameter of the irradiation chamber 12 ′ is L.

  The irradiation chamber 12 ′ having a cylindrical cavity is formed by hollowing out (cutting out) a regular quadrangular prism-shaped body member and bolting square bottom walls 13 ′ and 14 ′ to both ends thereof. And one place of the side wall which forms the side surface (namely, inner circumferential surface of the barrel member) of the irradiation chamber 12 ', in this case, the outer side of the outer side surfaces 15', 16 ', 17', 18 'of the barrel member On the side surface 15 ', an iris 11' similar to the first example opens. That is, the iris 11 ′ is also a rectangular opening whose major axis extends parallel to the central axis C connecting the centers of both bottom surfaces of the irradiation chamber 12 ′. Further, in order to fix the flange 22 of the waveguide 20 that couples microwaves through the iris 11 ′, a flange portion 15 a ′ is extended from the outer surface 15 ′.

  The microwave introduced from the waveguide 20 through the iris 11 ′ into the irradiation chamber 12 ′ generates a single mode electric field along the direction of the central axis C at the time of resonance. Since the irradiation chamber 12 ′ is a cylindrical cavity, in the case of the second example, if nothing is contained in the cavity resonator 10, the electromagnetic field in the TM010 mode is excited. When the frequency of the resonating microwave is 2,450 MHz, the diameter L when there is nothing in the irradiation chamber 12 'is 93.7 mm. As in the first embodiment, a dimensional difference of about ± several percent for L can be allowed.

  As in the first example, since the liquid to be processed which is a dielectric exists in the irradiation chamber 12 ′, the resonance frequency of the irradiation chamber 12 ′ is lowered under the influence. Therefore, L of the irradiation chamber 12 'is also designed to be smaller than the dimension when empty. In addition, as described above, when L is set to be long, problems such as mode competition that resonates in a higher-order mode may occur. Therefore, in consideration of these conditions, the circular shape formed by the bottom surface in the irradiation chamber 12 ′ is considered. The diameter L is suitably designed to be 80% or less of the wavelength of the microwave introduced into the irradiation chamber 12 ′. Note that the axial length H (the height of the cylinder) of the side surface of the irradiation chamber 12 ′ may be designed as appropriate because an electric field is generated in the direction of the central axis C.

  Comparing the cavity resonator 10 of the first example and the second example, the first example can be produced simply by assembling the six plate members together, and the waveguide 20 is also easier to attach. It has the advantage of being easy to make.

  A first embodiment of the flow pipe installed in the irradiation chambers 12 and 12 ′ of the cavity resonator 10 according to the first and second examples will be described with reference to FIGS. 4 and 5.

  The flow pipe 60 of the first embodiment is made of quartz glass as an example, and is a straight pipe having a length penetrating the irradiation chambers 12 and 12 ′. The flow pipe 60 has its axis C ′ aligned with the central axis C, which is the electric field direction of the irradiation chambers 12 and 12 ′, and in this embodiment, in particular, the axis C ′ is substantially coincident with the central axis C ( An error of several millimeters is allowed) and is installed in the irradiation chambers 12 and 12 '. As described above, since the central axis C of the irradiation chambers 12 and 12 ′ coincides with the direction of the electric field and the electric field is strongest, the flow pipe 60 is installed with the axial line C ′ substantially coincided with the central axis C. Thus, the liquid to be processed can be processed most efficiently. A mechanism for installing the flow pipe 60 so that the axis C ′ substantially coincides with the central axis C is shown in the sectional view of FIG.

  A circulation pipe 60 is held at the central portion of the bottom wall 13, 14 (13 ′, 14 ′) constituting the cavity resonator 10 without escaping microwaves generated in the irradiation chambers 12, 12 ′ to the outside. Therefore, the cylindrical member 19 having a height of about 50 mm is erected outward. The cylindrical member 19 has a diameter of about 20 mm (designed appropriately according to the size of the flow pipe 60), and a flange 19a is provided around the skirt portion, and on the outer surface of the bottom wall 13, 14 (13 ', 14'). The flange 19a is received in the correspondingly formed recess, and is fixed by tightening with a hexagon socket head cap screw or the like. The fixed internal space of the cylindrical member 19 communicates with through holes 13a and 14a (13'a and 14'a) provided in the center of the recesses of the bottom walls 13 and 14 (13 'and 14'). The central axis of the fixed cylindrical member 19 substantially coincides with the central axis C of the irradiation chambers 12 and 12 '.

  A lid member 61 made of a metal or a disk made of natural resin or synthetic resin is attached to a predetermined portion on one end side of the flow pipe 60. In the case of this embodiment, the lid member 61 is fitted to the cylindrical member 19 on the side of the bottom wall 13, 13 '. That is, a bulging portion 61 a having a diameter corresponding to the inner diameter of the cylindrical member 19 is formed on the inner surface of the lid member 61, and the bulging portion 61 a is fitted to the cylindrical member 19, so that the lid member 61 is The flow pipe 60 fixed and fitted with the lid member 61 is held by the cylindrical member 19. The lid member 61 can be screwed into the cylindrical member 19.

  The flow pipe 60 with the lid member 61 mounted on one end side is arranged with the other end side first (downward in the figure) and through the cylindrical member 19 of the bottom wall 13, 13 ′ located on the upper side in the figure, Insert into 12 '. The other end side of the inserted flow pipe 60 passes through the irradiation chambers 12 and 12 'and enters the cylindrical member 19 of the bottom wall 14 and 14' located on the opposite side. A position holding member 62 for positioning through the other end side of the flow pipe 60 is fixed in the distal end portion of the cylindrical member 19 by screwing or the like. The position holding member 62 has a disc shape, and a through hole having a diameter corresponding to the outer diameter of the flow pipe 60 is opened at the center. The other end of the flow pipe 60 is pierced through the through hole so that the central axis C And the axial line C ′ are positioned so as to substantially coincide with each other, and the other end side of the flow pipe 60 projects outward. Thus, one end side is held by the lid member 61 and passes through the cylindrical member 19 and hangs down in the irradiation chambers 12 and 12 ′, and the other end side passes through the opposite cylindrical member 19 and protrudes outward from the position holding member 62. The circulation pipe 60 is installed in the irradiation chambers 12 and 12 ′. By installing the flow pipe 60 using the cylindrical member 19 projecting in a chimney shape outward from the cavity resonator 10, microwave leakage from the irradiation chambers 12, 12 'is prevented.

  In this way, by adopting a system in which the flow pipe 60 fitted with the lid member 61 is inserted through the cylindrical member 19, the flow pipes 60 having different diameters can be replaced and installed. That is, the microwave processing can be performed by selecting and replacing the flow pipe 60 having an appropriate diameter according to the processing amount per unit time or the like.

  As shown in FIG. 5, the obstacle means 63 is accommodated in the flow pipe 60 installed in the irradiation chambers 12 and 12 '. The obstruction means 60 is held in the flow pipe 60 by, for example, packing the filter material 64 such as absorbent cotton or non-woven fabric at both ends (or only the lower end) of the flow pipe 60 and closing the cover. The obstacle means 63 shown in FIG. 5 is a large number of particles 63 of the same material accommodated in the flow pipe 60 (which will be described as a sphere, but may be other than a sphere), and the obstacle means 63 is present. As a result, the flow of the liquid to be processed flowing in the flow pipe 60 is disturbed. That is, the obstacle means 63 does not simply reduce the volume of the liquid to be processed in the flow pipe 60 but has the following important functions.

  If there is nothing in the flow pipe 60, the liquid to be processed flowing through the flow pipe 60 becomes a laminar flow, but the presence of the obstacle means 63 causes a turbulent flow in the liquid to be processed. By making the turbulent flow in the obstacle means 63, a stirring action of the liquid to be processed occurs, and a result of promoting the chemical reaction of the liquid to be processed can be obtained.

  Further, the obstacle means 63 is made of a material having a dielectric constant different from that of the liquid to be processed. The obstacle means 63 of the present embodiment is made of a material having a low dielectric constant and less microwave absorption (or no absorption) than the liquid to be treated, such as alumina (aluminum oxide), fluororesin, quartz, or borosilicate glass. ing. In addition to the above turbulent flow, since the dielectric constants of the liquid to be treated and the obstacle means 63 are different, the electric field distribution is not uniform in the flow pipe 60 through which the liquid to be treated flows, and the strength of the electric field is average. Decrease.

More specifically, first, in order to accelerate the reaction of the liquid to be treated, the following two matters need to be considered.
(1) It is necessary to consider giving appropriate activation energy to the liquid to be treated quickly. However, if too much is given, it will be a by-product generation factor. Therefore, it is necessary to apply activation energy uniformly to the liquid to be processed in the irradiation chamber in a short time.
(2) It is necessary to consider increasing the chance of contact between substances that react in the liquid to be treated. That is, even if uniform heating is realized, if the liquid to be treated flows in a laminar flow in the flow pipe, the reaction cannot be accelerated sufficiently. Therefore, a device for intentionally generating a turbulent flow of the liquid to be treated in the flow pipe is necessary.

  Second, in order to uniformly and quickly apply the activation energy, it is necessary to consider placing the liquid to be processed in a portion where the electric field in the irradiation chamber is strong. For example, a flow pipe is arranged along the central axis C of the irradiation chamber. However, in this case, in the liquid to be treated that absorbs a large amount of microwaves such as water, the Q is further lowered, and there is a risk that the resonance frequency is greatly lowered and falls out of the ISM band.

  The obstacle means 63 functions appropriately with respect to these three viewpoints: intentional generation of turbulent flow, suppression of Q reduction, and maintenance of the ISM band. The obstacle means 63 can carry a catalyst (solid catalyst) for a chemical reaction, and the obstacle means 63 can be used as a susceptor.

  FIG. 6 shows an example of an electric field simulation when water is passed as a liquid to be treated in the quartz flow pipe 60 containing the obstacle means 63 with respect to the above function. FIG. 6 (A) shows the result when the relative permittivity for water is lowered by using the obstacle means 63 as alumina particles, and FIG. 6 (B) shows the case where the relative permittivity of the obstacle means 63 is equal to water. Results are shown. The relative dielectric constant of water was set to 80, and the relative dielectric constant of alumina particles was calculated to be 10. Since water as the liquid to be treated has a large relative dielectric constant, a phenomenon that the resonance frequency is lowered is remarkable, microwave absorption is large, and Q is greatly reduced. For this reason, in the prior art, it was necessary to limit the inner diameter of the flow pipe to 1 mm or less.

  As shown in FIG. 6 (A), the presence of the obstacle means 63 that exhibits the above function makes the electric field distribution turbulent and non-uniform in the flow pipe 60. In particular, the strength of the electric field in water is reduced. It becomes weak on average. And the microwave absorption proportional to the square of an electric field reduces, and the fall of Q is suppressed. On the other hand, in the case of FIG. 6B, it can be seen that the electric field distribution does not change and remains strong, resulting in a decrease in resonance frequency and Q. That is, the disturbance means 63 having a dielectric constant different from that of the liquid to be treated is accommodated in the flow pipe 60 and the flow is disturbed, so that the decrease in the resonance frequency and the decrease in the Q are suppressed, and the resonance can be easily achieved in the ISM band. This is extremely advantageous in terms of device design.

  FIG. 7A shows a glass flow tube 60 having outer diameters of 3 mm and 4 mm (inner diameters of 1.6 mm and 2.4 mm), in which alumina particle obstruction means 63 having a diameter of 0.5 mm and 1 mm are provided. It is the figure of the result of having accommodated and experimenting in the cavity resonator 10 shown in FIG. 2 of TM110. The vertical axis represents the microwave frequency in the irradiation chamber 12, and the horizontal axis represents conditions 1 to 7. Condition 1 is a condition in which nothing is contained in the irradiation chamber 12, Condition 2 is a condition in which an empty distribution pipe 60 is set in the irradiation chamber 12, and Condition 3 is a condition in which the distribution pipe 60 containing 1 mm diameter obstacle means 63 is connected to the irradiation chamber 12. The condition 4 is set so that the treatment liquid (water) does not flow, and the condition 4 is a condition in which the flow pipe 60 containing the obstacle means 63 having a diameter of 0.5 mm is set in the irradiation chamber 12 and the treatment liquid (water) is not flowed. Condition 5 is a condition in which a flow pipe 60 containing 1 mm diameter obstruction means 63 is set in the irradiation chamber 12 and a liquid to be treated (water) is flowed. Condition 6 is a flow containing 0.5 mm diameter obstruction means 63. Condition 7 in which the tube 60 is set in the irradiation chamber 12 and the liquid to be processed (water) is flowed, condition 7 is that an empty flow pipe 60 that does not contain the obstacle means 63 is set in the irradiation chamber 12 and the liquid to be processed (water) ). In condition 7, the frequency decreases as the ISM band deviates significantly. In contrast, in conditions 5 and 6, it can be seen that the decrease in frequency is reduced to a level that can be controlled within the ISM band. That is, it can be read that the frequency reduction range of the conditions 5 and 6 is within 100 MHz with respect to the frequency of the condition 1 when there is nothing and can be easily controlled.

  FIG. 7B shows an example of calculating Q in a distribution pipe without obstruction means. In general, it is difficult to find resonance when the value of Q is 100 or less. However, in the case of water, for example, when the inner diameter of the flow pipe exceeds 1.5 mm, Q falls and tuning control becomes difficult. This decrease in Q is suppressed by accommodating the obstacle means 63, and the flow pipe 60 can be made thicker.

  As described above, as a result of the suppression of the microwave absorbed in the liquid to be treated, the flow pipe 60 has a larger diameter than before, for example, 3 mm or 4 mm (inner diameter 1.5 mm or more), and the flow rate of the liquid to be treated is increased. Even so, the decrease in Q is suppressed and it becomes easy to achieve synchronization. That is, the processing efficiency can be improved by increasing the flow rate of the liquid to be processed.

  FIG. 8 shows a second embodiment of the distribution pipe. The flow pipe 70 of this embodiment is made of quartz glass as an example, and has a double pipe structure having an inner flow path 71 and an outer flow path 72 surrounding the inner flow path 71. In the outer flow path 72 surrounding the inner flow path 71, a large number of small-diameter obstacle means 73 are accommodated as in the first embodiment. The inner flow path 71 has an inner diameter of 1.5 mm or less to suppress the flow rate and suppress the absorption of microwaves by the liquid flowing inside. Since the outer flow path 72 contains the obstacle means 73 having the above-described action, the diameter of the outer flow path 72 can be increased to increase the flow rate of the liquid to be processed. Both ends of the outer flow path 72 are covered with filter bodies 74 such as absorbent cotton or nonwoven fabric. According to the second embodiment, a coolant such as water other than the liquid to be treated can be allowed to flow through the inner flow path 71.

  FIG. 9 shows a third embodiment of the flow pipe. The flow pipe 80 of this embodiment is made of quartz glass as an example, and is, for example, a straight pipe having an inner diameter of 3 mm or more. The distribution pipe 80 is made of the same material as that of the first embodiment, and a linear obstacle means 81 wound in a spiral is accommodated. Both ends of the flow pipe 80 are filled with a filter body 82 such as absorbent cotton or nonwoven fabric so that the obstacle means 81 does not fall off. Even such a helical obstacle means 81 can cause a turbulent flow in the liquid to be processed flowing in the flow pipe 80, and can exhibit the same function as in the first embodiment. The obstruction means 81 can adopt other shapes that obstruct laminar flow, such as a mesh, in addition to being wound in a spiral.

  In addition to the above, the flow pipe may have a triple pipe structure. In this case, the innermost flow path can be used as the flow path 71 and the outermost flow path can be used as the flow path 72. And the example which accommodates a helical obstruction means like 3rd Embodiment of FIG. 9 in the intermediate flow path between these is possible. In this example, if the spiral obstruction means is sufficiently thick, the liquid to be treated can flow in a spiral state in the intermediate flow path.

  FIG. 10 shows a fourth embodiment of the distribution pipe. In this embodiment, heat shrinkable tubes 65 are attached to both ends of the flow pipe 60 of the first embodiment, and a joint described later is attached to the tips of these heat shrinkable tubes 65. As shown in FIG. 10 (B), in the case of the fourth embodiment, since the heat shrink tube 65 is attached to both ends, both the lid member 61 and the position holding member 62 are passed through the flow pipe 60 in advance, The heat shrinkable tubes 65 attached to both ends are held so as not to fall off. The flow pipe 60 is inserted into the irradiation chambers 12 and 12 ′ through the upper cylindrical member 19 with the position holding member 62 facing down. Then, the heat-shrinkable tube 65 and the position holding member 62 on the distal end side of the flow pipe 60 suspended in the irradiation chambers 12 and 12 ′ are inserted into the lower cylindrical member 19, and the heat-shrinkable tube 65 is removed from the cylindrical member 19. It is set so that it protrudes to. The position holding member 62 stays in the cylindrical member 19 and keeps the position of the distal end side of the flow pipe 60 as in the first embodiment. That is, the state after the distribution pipe 60 is set is the same as in the first embodiment.

  FIG. 11 shows a fifth embodiment in which the shape of the flow pipe is changed. The flow pipe 90 of this embodiment is made of quartz, borosilicate glass or the like as in the above embodiment, but the intermediate part other than the straight pipe part at both ends through which the cover member 61 and the position holding member 62 are passed is a spiral pipe. Is formed. However, similarly to the above embodiment, the spiral flow pipe 90 is also installed using the lid member 61, the insertion member 62, and the cylindrical member 19 so that the axis C ′ of the spiral center substantially coincides with the central axis C. The

  In the flow pipe 90, the boundary part between the straight pipe part and the helical pipe part at both ends (the helical pipe part starting part at both ends) is cylindrical when the flow pipe 90 is installed in the irradiation chamber 12, 12 ′. It is formed so as to be located in the member 19. That is, the formation length of the spiral tube portion is longer than the irradiation chambers 12 and 12 ′ (length H), and the spiral tube portion is formed to reach the inside of the cylindrical member 19. In the spiral flow pipe 90, the obstacle means similar to the above embodiments is accommodated.

  In the case of the fifth embodiment, if the number of turns (pitch) of the circulation pipe 90 is increased, the length of the pipe increases and the processing time increases. Conversely, if the number of turns of the spiral is reduced, the length of the pipe decreases and the processing time decreases. Therefore, the microwave treatment can be performed by selecting and replacing the circulation tube 90 having an appropriate number of turns and thickness according to the liquid to be treated. In the case of the spiral flow pipe, the flow in the direction crossing the direction of the electric field in the irradiation chamber is applied with respect to the direction in which the liquid to be processed flows.

The spiral winding diameter d1 of the flow pipe 90 according to the fifth embodiment is set as follows.
In the case of the cavity resonator 10 according to the first example, since the cross section of the irradiation chamber 12 is a square, the electric field changes depending on the location in the circumferential direction around the central axis C. That is, the electric field changes along the flow direction of the circulation pipe 90. This situation is simulated in FIG. The graph of FIG. 12 is a graph of the electric field change shown with the angle in the circumferential direction on the horizontal axis. As can be seen from FIG. 12, as d1 increases with respect to L of the irradiation chamber 12, that is, the center. The longer the distance (d1 / 2) from the axis C to the center of the inner diameter of the flow tube 90, the greater the change in the electric field along the flow tube 90. Therefore, in consideration of the uniformity of processing, it is better to suppress d1 to a level that is not affected by the change. Considering from the simulation results, if d1 / L ≦ 0.5, the electric field can be regarded as almost constant, so d1 is set to 50% or less of one side L of the square formed by the bottom surface of the irradiation chamber 12, that is, The distance d1 / 2 from the central axis C to the center of the inner diameter of the flow pipe 90 is preferably set to 25% or less.

FIG. 13 shows an example of a flow mechanism for flowing the liquid to be processed through the flow pipes 60, 70, 80, 90 of the above embodiments.
A cavity resonator 10 according to the first example is installed, and in the irradiation chamber 12, the flow pipes 60, 70, 80, 90 according to any of the above embodiments use the cylindrical member 19. It is stored as above. The heat-shrinkable tubes 65 shown in the fourth embodiment (FIG. 10) are attached to both ends of the flow pipes 60, 70, 80, 90 drawn from the cylindrical member 19. Of the heat shrinkable tubes 65 at both ends, the one coming out from the lower side is directed to the liquid feeding tube 101 of the container 100 storing the liquid to be treated before treatment, and the one coming out from the upper side is the liquid to be treated after treatment. Are connected to the liquid feeding tube 103 of the container 102 for storing the liquid via the joint 104, respectively.

  The container 100 before processing is provided with a flow control cock 105 at the spout, and the vertical position can be adjusted. In the treated container 102, the liquid to be processed flows from the lower end part, and when the liquid reaches the spout at the upper end part, the processed liquid is discharged into a beaker or the like. This flow mechanism is a mechanism for flowing the liquid to be processed from the bottom to the top in the flow pipes 60, 70, 80, 90 in the irradiation chamber 12, and by adjusting the height of the container 100 and the flow rate control cock 105, Control the flow of liquid. The liquid to be processed after processing can be stored in the container 102 up to the liquid level in the container 100 before processing.

  The liquid supply tube 103 connected to the treated container 102 is connected to the joint 104 via the T-shaped pipe joint 106. The T-shaped pipe joint 106 includes one inlet and two outlets connected to the joint 104, and one of the two outlets is connected to the liquid feeding tube 103. The other outlet of the T-shaped pipe joint 106 is closed with a temperature measuring device 107 fixed by a thermocouple or the like. The temperature measuring device 107 measures the temperature of the liquid to be processed after the microwave treatment and provides it to the controller 40 in FIG.

DESCRIPTION OF SYMBOLS 10 Cavity resonator 12,12 'Irradiation chamber 19 Cylindrical member 19a Flange 60,70,80,90 Flow pipe 61 Lid member 61a Expansion part 62 Insertion member 63,73,81 Obstruction means 64,74,82 Filter body 71 Inner channel 72 Outer channel C Center axis C ′ Axis

Claims (4)

A single-mode cavity resonator having an irradiation chamber that is a square columnar cavity or a cylindrical cavity;
A flow pipe installed in the irradiation chamber along the axis with respect to the direction of the electric field generated in the irradiation chamber;
Disturbing means that has a different dielectric constant from the liquid to be treated flowing through the flow pipe, is contained in the flow pipe and disturbs the flow of the liquid to be treated,
A microwave device comprising:   The microwave device according to claim 1, wherein the flow pipe is replaceable. A flow tube that can be used in a microwave device including a single-mode cavity resonator having an irradiation chamber that is a rectangular columnar cavity or a cylindrical cavity,
It has a different dielectric constant from the liquid to be treated flowing through the flow pipe and contains an obstacle means for disturbing the flow of the liquid to be treated.
A flow pipe installed in the irradiation chamber along an axis with respect to a direction of an electric field generated in the irradiation chamber.   The flow pipe according to claim 3, wherein the flow path has a double pipe structure including an inner flow path and an outer flow path surrounding the inner flow path, and the obstacle means is accommodated in the outer flow path.