JP2014182930A - Circulation tube and microwave device having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microwave device capable of obtaining an adequate yield even with an increased throughput, and a circulation tube of the microwave device.SOLUTION: In a microwave device 100 which arranges a circulation tube 60 within a cavity resonator 30 for resonating a microwave and performs heat treatment on a liquid flowing in the circulation tube 60, the circulation tube 60 comprises: a tube part for heating 61 which heats the temperature of the liquid to a first temperature; and a tube part for temperature maintenance 62 which maintains the temperature of the liquid passing through the tube part for heating 61 within a scope between the first temperature and a second temperature that is higher than the first temperature.

Description

  The present invention relates to an apparatus for performing processing such as heating and chemical reaction promotion on a substance by irradiation with microwaves.

  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 oven-type batch type device in which a liquid is contained in a test tube or a flask for processing is currently mainstream. However, since batch processing cannot be performed continuously and processing capacity (amount of processing) is limited, a flow-type microwave device is considered that forms a flow tube and irradiates microwaves while flowing liquid through it. ing.

  As this type of flow-type microwave device, one described in Patent Document 1 is known. The microwave device described in Patent Document 1 introduces microwaves into a cavity in a cavity resonator to resonate, generates a single-mode electric field, and passes through the flow pipe disposed in the cavity. The flowing liquid is heated. The flow pipe is formed of a serpentine tube, and is arranged in the cavity so that the center of the spiral is substantially parallel to the direction of the single mode electric field in the cavity.

JP 2012-75996 A

  Here, in this type of flow-type microwave apparatus, in order to sufficiently promote the chemical reaction and obtain the substance to be generated, the temperature of the liquid in the flow pipe is set to the temperature at which the chemical reaction starts (reaction start temperature). It is necessary to maintain for a sufficient time within a temperature range below the temperature at which no harmful side reaction occurs.

  In the microwave device described in Patent Document 1, when the flow velocity of the liquid flowing through the circulation pipe composed of the serpentine pipe is low, the liquid that has flowed is heated, and then the heat absorption from the microwave in the liquid and the circulation pipe and the cavity from the liquid are performed. The liquid temperature can be maintained for a sufficient time within the above temperature range due to a balance with heat radiation by heat conduction to the resonator.

  However, in the microwave device described in Patent Document 1, when the flow rate is increased to increase the throughput per unit time without changing the microwave output, the temperature rise of the liquid becomes gradual and the reaction start temperature is reached. Since the reaching part moves to the outlet side (downstream side) of the flow pipe, the time for maintaining the temperature of the liquid at the reaction start temperature is shortened. On the other hand, if the microwave output is increased, even if the flow rate is increased, the portion that reaches the reaction start temperature can be prevented from moving downstream, but in this case, the temperature of the liquid reaches the reaction start temperature. After that, the temperature may be further raised to exceed the above temperature range. For these reasons, as the throughput per unit time increases, the chemical reaction of the liquid cannot be promoted sufficiently, and the amount of substance to be actually obtained decreases, resulting in a yield (= actually obtained object to be produced). There is a risk of causing a decrease in the amount of substance / the amount of treatment.

  The present invention has been made paying attention to the above problems, and an object of the present invention is to provide a microwave device capable of obtaining a sufficient yield even when the processing amount per unit time is increased, and a distribution pipe thereof.

  For this reason, the microwave device of the present invention is a microwave device in which a circulation pipe is disposed in a cavity resonator that resonates microwaves, and the liquid flowing through the circulation pipe is heated. The heating pipe part for raising the temperature of the liquid to the first temperature and the temperature of the liquid flowing through the heating pipe part are within the range of the second temperature higher than the first temperature from the first temperature. And a temperature maintaining tube for maintaining the temperature.

  The flow tube of the present invention is a flow tube that is disposed in the cavity resonator of the microwave device including a cavity resonator that resonates microwaves, and that circulates the liquid, and the temperature of the liquid is adjusted. A temperature for maintaining the temperature of the heating pipe part for raising to the first temperature and the temperature of the liquid flowing through the heating pipe part within the range of the second temperature higher than the first temperature from the first temperature. And a maintenance pipe part.

  According to the microwave device of the present invention, the flow pipe disposed in the cavity resonator for resonating the microwave includes the heating pipe portion for raising the temperature of the liquid to the first temperature, and the heating pipe. The temperature of the liquid flowing through the section is configured to include a temperature maintaining pipe section for maintaining the temperature within a range from the first temperature to the second temperature higher than the first temperature. It is possible to separately construct the distribution pipe structure and the temperature maintenance distribution pipe structure. Therefore, for example, the structure of the temperature maintaining pipe part can be the same as a conventional tube structure, and the structure of the heating pipe part can be a straight pipe structure that can be heated more rapidly than before, so the flow rate is increased. In addition, it is possible to prevent the portion that reaches the reaction start temperature from moving to the outlet side of the flow pipe. Thereby, even if the throughput per unit time is increased, it is possible to suppress the time for maintaining the temperature of the liquid at the reaction start temperature from being shortened, and a sufficient yield can be obtained.

  Further, according to the flow pipe of the present invention, the heating pipe part for raising the temperature of the liquid to the first temperature and the temperature of the liquid flowing through the heating pipe part are changed from the first temperature to the first temperature. Since it is configured to include the temperature maintaining pipe portion for maintaining within the higher second temperature range, the heating flow pipe structure and the temperature maintaining flow pipe structure can be constructed separately. Therefore, if a flow pipe structure for heating and temperature maintenance is appropriately constructed and placed in the cavity of the microwave device, a sufficient yield can be obtained even if the throughput per unit time is increased. Can be provided.

1 is a schematic configuration diagram of a first embodiment of a microwave device according to the present invention. It is the schematic of the cavity resonator of the said embodiment, (A) is the front view seen from the same side as FIG. 1, (B) is a left side view, (C) is a top view. It is the figure which showed the arrangement | positioning state of the flow pipe in the cavity resonator of the said embodiment. It is drawing for demonstrating the relationship between the flow direction of the liquid in the said embodiment, and the direction of an electric field, (A) is a fragmentary sectional view of the flow pipe in a heating pipe part, (B) is in a temperature maintenance pipe part. It is a fragmentary sectional view of a distribution pipe. It is a figure which shows the flow pipe in 2nd Embodiment of the microwave apparatus which concerns on this invention. It is a figure which shows the flow pipe in 3rd Embodiment of the microwave apparatus which concerns on this invention. It is an example which simulated the electric field which generate | occur | produces in the cavity resonator of the microwave apparatus which concerns on this invention. It is a conceptual diagram for demonstrating position adjustment of the flow pipe in a cavity resonator. It is a figure which shows the modification of the distribution pipe in 1st Embodiment. It is a figure which shows the result of having measured the change of the resonant frequency at the time of changing the structural ratio of the pipe part for a heating in a flow pipe, and the pipe part for temperature maintenance.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a first embodiment of a microwave device according to the present invention.
1, the microwave device 100 includes a microwave generator 10, a waveguide 20, a cavity resonator 30, a control device 40, an antenna 50, and a flow tube 60 (see FIG. 2). The microwave generator 10 is connected to the waveguide 20 via a coaxial cable or the like, and the waveguide 20 and the antenna 50 are assembled to the cavity resonator 30 and controlled by the controller 40. Yes.

  The microwave generator 10 generates microwaves and includes, for example, a variable frequency oscillator 11 and a variable amplifier 12. The variable frequency oscillator 11 outputs a microwave and outputs it at a predetermined frequency within a range of 2.4 GHz to 2.5 GHz which is an ISM frequency band using, for example, a solid element. The variable amplifier 12 variably amplifies microwave power. The frequency of the variable frequency oscillator 11 and the power of the variable amplifier 12 are controlled by the controller 40.

  The waveguide 20 guides the microwave output from the microwave generator 10 and introduces it to the cavity resonator 30. Specifically, the microwave from the microwave generator 10 is sent to the coaxial waveguide converter 21 via the isolator 13 and the directional coupler 14 connected by a coaxial cable. Then, the microwave guided by the waveguide 20 through the coaxial waveguide converter 21 is introduced into the cavity resonator 30 through an iris 31 described later.

  The cavity resonator 30 has an irradiation chamber 32 as a cavity that resonates by introducing the microwave from the microwave generator 10, and generates a single mode electric field in the irradiation chamber 32 by the resonance of the microwave. It is something to be made. Specifically, as shown in FIGS. 2A to 2C, the cavity resonator 30 includes an upper wall 33, a bottom wall 34, and side walls 35, 36, 37, and 38. . The upper wall 33 and the bottom wall 34 face each other and are square. The side walls 35, 36, 37, and 38 are each rectangular, and the short sides thereof are fixed to the sides of the upper wall 33 and the bottom wall 34 with bolts or the like (not shown). In this way, a rectangular columnar (regular quadratic columnar) cavity irradiation chamber 32 is formed in the casing formed by assembling the upper wall 33, the bottom wall 34, and the side walls 35, 36, 37, 38. In the case of the present embodiment, the side wall 35 on the waveguide 20 side is connected to the flange 22 of the waveguide 20 to connect the waveguide 20 as shown in FIGS. 2 (B) and 2 (C). The area has been expanded in correspondence.

  The iris 31 is a coupling slit for introducing microwaves into the irradiation chamber 32, and is opened as a rectangular opening at the central portion of the side wall 35 that forms the side surface of the irradiation chamber, as shown in FIG. This rectangular opening is rectangular, and its long axis extends parallel to the center axis C connecting the centers of the upper surface and the bottom surface of the irradiation chamber 32, that is, the centers of the upper wall 33 and the bottom wall 34.

  The microwave introduced through the iris 31 into the irradiation chamber 32 of the square columnar cavity generates a single mode electric field in a direction parallel to the central axis C at the time of resonance. Strictly speaking, if nothing is contained in the cavity resonator 30, the electromagnetic field of the TM110 mode is excited. Therefore, an electromagnetic field having a distribution approximately in accordance with the TM110 mode electromagnetic field distribution is generated in the irradiation chamber 32. For example, in the case of a microwave having a frequency of 2.45 GHz that is generally used in heating or the like, a single mode electric field can be generated between the side wall 35 and the side wall 37 when there is nothing in the irradiation chamber 32. The distance L and the distance L between the side wall 36 and the side wall 38 (see FIG. 2C) are each designed to be 86.5 mm. However, in reality, since there is a liquid serving as a dielectric in the irradiation chamber 32, the resonance frequency of the irradiation chamber 32 decreases due to the influence. Therefore, the distance L between the side walls is designed to be smaller than the dimension when empty (86.5 m in this example), and is set to a value that can resonate when there is liquid in the irradiation chamber 32 and the resonance frequency is lowered. It is good. Note that an error of L is allowed about ± several percent. Further, the distance H (see FIG. 2A) between the upper wall 33 and the bottom wall 34 in the irradiation chamber 32, that is, the height of the quadrangular prism may be designed with a necessary length as appropriate.

  The iris 31 is involved in setting the electromagnetic field excited in the irradiation chamber 32 only to the scheduled single mode (TM110). In the iris 31 shown in FIG. 2B, a microwave current flows in the long side (side edge) in a direction parallel to the central axis C, and the magnetic field surrounding the central axis C due to this current An electric field parallel to the central axis C is generated. An optimum value of the width of the iris 31 (direction orthogonal to the central axis C) can be obtained by simulation and experiment. The cavity resonator 30 may generate a TE mode. However, since an unexpected phenomenon may occur when the TE mode occurs, it is necessary to suppress the TE mode as much as possible. In the relationship between the waveguide 20 and the iris 31 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.

  In addition, cylindrical members 39 and 39 ′ that support both ends of the flow pipe 60 without escaping the microwave introduced into the irradiation chamber 32 to the outside are disposed at the central portions of the upper wall 33 and the bottom wall 34, respectively. ing. For example, as shown in FIG. 3, the cylindrical member 39 on the upper wall 33 side includes a cylindrical portion 39a and a flange portion 39b, and the cylindrical member 39 ′ on the bottom wall 34 side has a cylindrical portion 39a ′. And a flange portion 39b '. Each cylindrical portion 39a, 39a 'is formed with, for example, a height of about 50 mm and a cylinder inner diameter of about 22 mm (designed appropriately according to the size of the flow pipe 60), and a flange portion 39b, 39b' is formed around one end thereof. The flange portions 39b and 39b ′ are received in the concave portions provided on the outer surfaces of the upper wall 33 and the bottom wall 34, and are fastened and fixed by hexagon socket head bolts or the like. The other end sides of the cylindrical portions 39a and 39a 'are closed by lid members 60a and 60a' attached to the end portions of the flow pipe 60, respectively. The lid members 60 a and 60 a ′ are fixed to the flow pipe 60 and configured to be removable from the cylindrical cavity resonator 30 together with the flow pipe 60. The cylinder interiors 39c and 39c 'of the cylindrical members 39 and 39' communicate with the irradiation chamber 32 through a through hole provided in the center of the concave portion of the upper wall 33 and the bottom wall 34. The cylindrical members 39 and 39 ′ are positioned so that their central axes substantially coincide with the central axis C of the irradiation chamber 32. The lid members 60a and 60a 'have a through hole having a diameter corresponding to the outer diameter of the flow pipe 60 at the center thereof, and the ends of the flow pipe 60 are inserted into the through holes so as to protrude outward. . The cylindrical members 39, 39 ′ are lid members so that the center axis C of the irradiation chamber 32 and the spiral center of the downstream side serpentine tube 62 and the axis C ′ of the straight pipe portion 61 (described later) of the flow pipe 60 substantially coincide. The flow pipe 60 is positioned through 60a and 60a ′ to support both ends of the flow pipe 60 and prevent microwave leakage from the irradiation chamber 32 to the outside.

  Returning to FIG. 1, the controller 40 controls the microwave generator 10. For example, the control unit 40 is input with the detection result of the strength of the electric field or magnetic field detected by two antennas 50 (for example, loop-shaped antennas) spaced apart in the central axis direction, and the temperature of the liquid Measurement results are input, and the microwave generator 10 is controlled according to these inputs. One of the two antenna outputs is used for observation and the other is used for control. For example, the lower antenna of the cavity resonator 30 is used for control, and the upper antenna is used for observation. The antenna 50 only needs to be at least for control.

  More specifically, when an operation for starting microwave irradiation is performed, the controller 40 starts microwave output by the microwave generator 10 and executes a frequency control process. The frequency control process is, for example, a control process for tuning the frequency of the microwave output from the microwave generator 10 to the resonance frequency of the irradiation chamber 32 according to the detection result by the lower antenna 50. The controller 40 determines the tuning frequency from the detection result by the antenna 50 while sweeping the frequency of the variable frequency oscillator 11. At this time, the control unit 40 may instruct the variable amplifier 12 to perform amplification with 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 chamber 32, it is possible to suppress the influence that can be given to the liquid during the execution of the frequency control process. The controller 40 executes a power control process for controlling the power of the microwave following the tuning by the frequency control process. In the power control process, the microwave power is controlled by controlling the variable amplifier 12 of the microwave generator 10 according to the conditions set based on the type of liquid and the reaction start temperature described later by the operator before the start of microwave irradiation. It is a process to do. In the power control process, the controller 40 adjusts the power of the microwave output from the microwave generator 10 according to the detection result by the antenna 50 (or the temperature measurement result of the object to be processed). Both the detection result of the antenna 50 and the temperature measurement result may be used to improve the accuracy of power adjustment in the power control process.

  For example, the controller 40 first executes a frequency control process at the start of microwave irradiation, then executes a power control process, and interrupts and executes the frequency control process at regular intervals during the execution of the power control process. . In the frequency control process, the controller 40 controls the variable amplifier 12 to output the microwave with the above-mentioned weak power, and controls the variable frequency oscillator 11 to tune the frequency.

  Next, the flow pipe 60 disposed in the irradiation chamber 32 of the cavity resonator 30 will be described in detail with reference to FIG.

  First, the basic configuration of the distribution pipe 60 will be described. The circulation pipe 60 circulates the liquid to be heat-treated, and is provided on the downstream side of the heating pipe part and the heating pipe part for raising the temperature of the liquid to the first temperature. And a temperature maintaining pipe section for maintaining the temperature of the liquid flowing through the section within a range from the first temperature to the second temperature higher than the first temperature. The first temperature is a starting temperature of a chemical reaction for obtaining a substance to be generated (hereinafter referred to as “reaction starting temperature”), and the second temperature is a temperature at which no harmful side reaction occurs, That is, it is the upper limit temperature at which there is no possibility that a substance different from the generation target is generated.

Specifically, the angle formed between the direction of the single-mode electric field generated in the cavity resonator 30 (irradiation chamber 32) by microwave resonance and the flow direction F ₁ of the liquid in the heating tube section is expressed as follows. It is configured to be smaller than an angle formed by the direction and the flow direction F ₂ of the liquid in the temperature maintaining pipe portion. As described above, since the electric field is generated in a direction substantially parallel to the central axis C of the irradiation chamber 32, the angle between the direction of the electric field and the flow direction (F ₁ , F ₂ ) is the flow between the central axis C and the flow. It can be expressed by an angle θ formed with the direction (F ₁ , F ₂ ). Strictly speaking, the angle θ is a smaller angle (that is, an inferior angle) between the central axis C and the flow direction (F ₁ , F ₂ ). More specifically, in the present embodiment, the flow pipe 60 is made of, for example, quartz glass, and includes a straight pipe section 61 as a heating pipe section and a downstream side serpentine pipe section 62 as a temperature maintaining pipe section. It is comprised including.

The straight pipe portion 61 is a straight pipe disposed on the upstream side of the downstream side serpentine pipe portion 62 and extending in a direction substantially parallel to the direction of the electric field (that is, the central axis C), and one end side is covered with the cylindrical member 39 ′. It is supported via the member 60 a ′, and the other end side is connected to the downstream side serpentine tube portion 62. The flow direction F ₁ in the straight pipe portion 61, since the center axis C is substantially parallel to, the angle is substantially zero. Therefore, the angle in the straight pipe portion 61 is smaller than the angle θ (subordinate angle) formed by the flow direction F ₂ and the central axis C in the downstream side serpentine tube portion 62. As described above, the flow pipe 60 in the present embodiment uses the heating pipe section as a straight pipe and the temperature maintaining pipe section as a serpentine pipe, whereby the electric field direction and the liquid flow direction F ₁ in the heating pipe section are Is configured to be smaller than an angle formed between the direction of the electric field and the flow direction F ₂ of the liquid in the temperature maintaining tube portion.

  In this embodiment, the straight pipe portion 61 is positioned so that the straight pipe axis C ′ substantially coincides with the central axis C by using the tubular member 39 ′ and the lid member 60a ′ as described above. Is done. The inner diameter of the straight pipe portion 61 is, for example, about 3 mm to 5 mm. The inner diameter of the straight pipe portion 61 and the length of the portion of the straight pipe portion 61 where the microwave is irradiated in the irradiation chamber 32 depend on the type of liquid, the size of the irradiation chamber 32, the reaction start temperature, the liquid flow rate, and the like. It is designed accordingly.

  The downstream serpentine tube portion 62 is a serpentine tube that is disposed on the downstream side of the straight tube portion 61 and extends spirally from the straight tube portion 61. For example, the center of the spiral is the axis C of the straight tube portion 61. It is wound in a spiral around this axis C 'in line with'. One end side of the downstream side serpentine tube portion 62 is connected to the straight tube portion 61, and the other end side is connected to a straight tube supported by the tubular member 39 via the lid member 60a. The angle θ in the downstream side serpentine tube portion 62 is larger than the angle in the straight tube portion 61. It should be noted that the spiral center and the axis C ′ are not necessarily coincident. This modification will be described in detail later with reference to FIG.

  In the case of the present embodiment, the downstream side serpentine tube portion 62 is positioned so that the spiral center (axis C ′) substantially coincides with the central axis C using the tubular member 39 as described above. The other end side (tubular member 39 side) of the downstream side serpentine tube portion 62 is, for example, as shown in FIG. 3, when the flow pipe 60 is installed in the irradiation chamber 32, Part) is disposed so as to be located in the cylinder interior 39c of the cylindrical member 39. The inner diameter of the downstream side serpentine tube portion 62 is, for example, about 3 mm to 5 mm, and may be matched with or different from the inner diameter of the straight tube portion 61. Considering the manufacturing cost of the flow pipe 60, it is better to match the inner diameter and outer diameter of the straight pipe section 61 and the downstream side serpentine pipe section 62. The winding outer diameter D of the downstream side serpentine tube portion 62 is, for example, about φ20 mm. The spiral winding pitch of the downstream side serpentine tube portion 62 is determined by the angle θ and the winding outer diameter D of the downstream side serpentine tube portion 62. In the present embodiment, the spiral winding pitch is wound at a constant winding pitch. For example, when the length of the electric field direction (central axis C) (ie, the total length) and the winding outer diameter D of the downstream side serpentine tube 62 are the same, increasing the angle θ increases the total number of turns and increases the liquid flow length. Since the length of the liquid becomes longer, the residence time of the liquid in the irradiation chamber 32 is increased. Conversely, when the angle θ is decreased, the total number of turns is reduced and the flow length is shortened, so that the residence time is reduced. Further, the inner diameter, outer diameter, angle θ, and total length of the downstream side serpentine tube portion 62 are appropriately designed according to the type of liquid, the size of the irradiation chamber 32, the reaction start temperature, the liquid flow rate, and the like.

Here, the relationship between the flow direction of the liquid and the direction of the electric field will be described with reference to FIG.
4A shows that the flow direction F _{1 of the} liquid flowing in the straight pipe portion 61 is substantially parallel to the direction of the electric field (center axis C), and FIG. 4B shows the downstream side serpentine portion 62. The flow direction F _{2 of the} liquid flowing inside traverses the central axis C. Since the liquid flowing through the flow pipe 60 can be regarded as a dielectric, in the case of FIG. 4A, the dielectric boundary is parallel to the electric field, and in the case of FIG. 4B, the dielectric boundary crosses the electric field. . Therefore, when the electric field and the dielectric boundary are parallel, the electric field strength is the same inside and outside the dielectric. Then, as the direction of the dielectric boundary changes from a state parallel to the direction of the electric field (FIG. 4A) to a state orthogonal to the direction of the electric field, the strength of the electric field in the dielectric decreases. Therefore, the strength of the electric field in the dielectric body becomes weaker as the angle (recess angle) θ between the flow direction and the electric field direction becomes larger. In other words, the strength of the electric field in the dielectric body decreases as the inclination angle of the spiral of the serpentine tube with respect to the direction orthogonal to the direction of the electric field decreases.

Further, the microwave power (energy per unit time) absorbed by the dielectric is given by the following equation.
P _L = (1/2) · ∫ _V ωε ₀ ε _r ″ E ² dv
In the equation, ω is an angular frequency, and ε ₀ is a vacuum dielectric constant of 8.854 × 10 ⁻¹² (Coulomb / m). The relative dielectric constant (complex number) εr is defined by εr = εr′−jεr ″.
In FIG. 4B, in order to simplify the description, when the liquid is water and the angle θ is 90 °, εr ′ of water is about 80 (room temperature) and εr ″ is about 10, so that FIG. Compared with the case of A), the electric field is 1/80 (1 / εr ′).
That is, assuming that the liquid flows through the flow pipe 60, in the case of FIG. 4A in which the liquid flows along the central axis C, the absorption of microwaves into the liquid is very large, but the central axis C is spiral. In the case of FIG. 4B in which the liquid flows around, the absorption of microwaves into the liquid is greatly reduced. That is, as the angle θ approaches 90 ° from 0 °, there is a characteristic that the absorption of microwaves into the liquid increases. Further, as the angle θ approaches 90 ° from 0 °, the action of reducing the resonance frequency of the cavity resonator 30 becomes stronger.

  Next, the operation of the microwave device 100 of this embodiment will be schematically described. For simplification of explanation, it is assumed that frequency control and power control by the control unit 40 have been completed, and a microwave is introduced into the irradiation chamber 32 to generate an electric field in a direction substantially parallel to the central axis C. It will be described as being.

  When the liquid begins to flow into the flow pipe 60 at a predetermined flow rate, the straight pipe portion 61 causes the liquid to flow along the central axis C to the downstream side serpentine portion 62 side. At this time, since the electric field is substantially parallel to the flow direction of the liquid, the microwave is sufficiently absorbed by the liquid in the straight pipe portion 61. Thereby, the liquid is heated at a predetermined temperature increase rate, and the temperature of the liquid is increased so as to reach the reaction start temperature (first temperature) in the vicinity of the downstream end of the straight pipe portion 61. The liquid heated up to the reaction start temperature then flows in the downstream side serpentine tube portion 62. At this time, since the electric field crosses the downstream side serpentine tube part 62, the strength of the electric field in the liquid is weakened according to the angle θ formed by the direction of the electric field and the flow direction, and the absorption of the microwave into the liquid is absorbed in the straight pipe unit 61. Decrease than absorption. During the flow through the downstream side serpentine tube 62, the temperature of the liquid is determined by the heat absorption from the microwave in the liquid flowing in the downstream side serpentine tube 62 and the heat from the liquid to the downstream side serpentine tube 62 and the cavity resonator 30. The temperature is maintained within a temperature range between the first temperature and the second temperature for a predetermined time due to balance with heat dissipation by conduction. Thereby, the target chemical reaction process is performed, and the substance to be generated is caused to flow out of the flow pipe 60. The predetermined time is appropriately determined according to the substance to be generated.

  According to the microwave device 100 having such a configuration, the flow pipe 60 disposed in the cavity resonator 30 that resonates the microwave includes the heating pipe section for raising the temperature of the liquid to the first temperature, Since the temperature of the liquid flowing through the heating pipe section is configured to include the temperature maintaining pipe section for maintaining the temperature within the range from the first temperature to the second temperature higher than the first temperature, The temperature distribution pipe structure and the temperature maintenance flow pipe structure can be constructed separately. For example, the structure of the temperature maintaining pipe section is the downstream side serpentine pipe section 62 having the same serpentine pipe structure as the conventional one, and the structure of the heating pipe section is the straight pipe section 61 having a straight pipe structure capable of heating more rapidly than the conventional one. Thereby, even if the flow rate increases, it is possible to prevent the portion that reaches the reaction start temperature from moving to the outlet side of the flow pipe. As a result, even if the throughput per unit time is increased, it is possible to suppress the time for maintaining the temperature of the liquid in a predetermined temperature range from being shortened, and a sufficient yield can be obtained.

Further, in the present embodiment, the flow pipe 60 only needs to form a straight pipe on one end side of the serpentine pipe longer than a straight pipe on the other end side, and therefore, a flow combining a heating pipe section and a temperature maintaining pipe section. The tube 60 can be easily formed. In the present embodiment, since the central axis C of the irradiation chamber 32 coincides with the direction of the electric field and is the place where the electric field is strongest, the axis C ′ of the straight pipe portion 61 is substantially coincident with the central axis C. By installing the straight pipe portion 61, the temperature of the liquid can be most efficiently raised in the straight pipe portion 61. Note that the axis C ′ does not necessarily coincide with the central axis C when the required electric field strength is obtained. In the present embodiment, the downstream side serpentine tube portion 62 is shown as being wound at a constant winding pitch. However, the present invention is not limited to this example. For example, the downstream side serpentine tube portion 62 is formed so that the winding pitch decreases toward the downstream side. May be. In other words, in this case, the angle θ formed by the direction of the electric field and the flow direction F ₂ of the liquid in the temperature maintaining tube portion is set so as to increase toward the downstream side of the liquid flow. In this modification, in the downstream side serpentine tube portion 62, the amount of absorption of microwaves into the liquid can be reduced toward the downstream side.

  FIG. 5 shows a cross-sectional view of the cavity resonator 30 of the microwave device 100 according to the second embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the element same as 1st Embodiment, description is abbreviate | omitted, and only a different part is demonstrated.

  In the present embodiment, the heating pipe part and the temperature maintaining pipe part of the flow pipe 60 are each made of a serpentine pipe. Specifically, as shown in FIG. 5, the heating tube portion is composed of an upstream side serpentine tube portion 61 ′ whose spiral center coincides with the central axis C and is spirally wound around the central axis C. The temperature maintaining pipe part is disposed on the downstream side of the upstream side serpentine part 61 ', and the spiral center thereof coincides with the spiral center (that is, the central axis C) of the upstream side serpentine part 61' so It consists of downstream side serpentine tube part 62 'wound in a shape. The flow pipe 60 uses, for example, the downstream side serpentine part 62 of the first embodiment as the downstream side serpentine part 62 ', and replaces the upstream side serpentine part 61' downstream with the straight pipe part 61 of the first embodiment. It is configured to be connected to the side serpentine tube 62 ′ (62). It should be noted that the spiral center of the upstream serpentine tube portion and the spiral center of the downstream serpentine tube portion do not necessarily have to coincide with each other.

The upstream side serpentine part 61 ′ is formed such that the spiral inclination angle with respect to the direction orthogonal to the direction of the electric field is larger than the inclination angle of the downstream side serpentine part 62 ′. As described above, the flow pipe 60 in the present embodiment makes the spiral inclination angles of the respective serpentine tubes 61 ′ and 62 ′ different between the upstream side and the downstream side, and the upstream side has a rough predetermined winding pitch (upstream side serpentine pipe). part 61 ') and, downstream of the fine predetermined winding pitch flexible tube (downstream flexible tube section 62' by a), the angle between the flow direction F ₁ 'of the liquid in the direction and the heating tube portion of the field θ ₁ is configured to be smaller than an angle θ ₂ formed by the direction of the electric field and the flow direction F ₂ of the liquid in the temperature maintaining tube portion.

  The inner diameter of the upstream side serpentine part 61 ′ is, for example, about 3 mm to 5 mm, and may be matched with or different from the inner diameter of the downstream side serpentine part 62 ′ (downstream side serpentine pipe part 62). Considering the manufacturing cost of the flow pipe 60, it is better to match the inner diameter and the outer diameter of the upstream side serpentine part 61 'and the downstream side serpentine part 62'. In addition, the winding outer diameter of the upstream side serpentine tube 61 ′ is, for example, about φ20 mm together with the winding outer diameter D of the downstream side serpentine tube 62 ′ (downstream side serpentine tube 62). The inner diameter, outer winding diameter, angle, and total length (length in the electric field direction) of the upstream side serpentine tube portion 61 ′ and the downstream side serpentine tube portion 62 ′ are respectively the type of liquid, the size of the irradiation chamber 32, the reaction start temperature, and the reaction start temperature. It is designed appropriately according to the flow rate of the liquid.

  According to the microwave device 100 having such a configuration, as in the first embodiment, even when the processing amount per unit time is increased, it is possible to suppress the time during which the liquid temperature is maintained in a predetermined temperature range from being shortened. And a sufficient yield can be obtained.

In the second embodiment, the upstream side serpentine tube portion 61 ′ and the downstream side serpentine tube portion 62 ′ have been described as being wound at a constant winding pitch as shown in FIG. 5, but the present invention is not limited thereto. Each of the serpentine tube portions 61 ′ and 62 ′ may be formed so that the winding pitch becomes smaller toward the downstream side. Further, one winding pitch of each of the serpentine tube portions 61 ′ and 62 ′ may be constant, and the other winding pitch may be reduced toward the outflow side. That is, the angle (θ ₁ , θ ₂ ) of at least one of the heating tube portion and the temperature maintaining tube portion may be set so as to increase toward the downstream side. In the case of this modification, the respective winding pitches at the boundary portion (connection portion) between the upstream side serpentine tube portion 61 ′ and the downstream side serpentine tube portion 62 ′ may be different as shown in FIG. Also good.

  FIG. 6 is a sectional view of the cavity resonator 30 of the microwave device 100 according to the third embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the element same as 1st Embodiment, description is abbreviate | omitted, and only a different part is demonstrated.

  In the present embodiment, the heating pipe portion of the flow pipe 60 includes a first straight pipe 63 that extends in a direction substantially parallel to the direction of the electric field (center axis C). The temperature maintaining pipe portion of the flow pipe 60 is a straight pipe extending from the first straight pipe 63 and having a diameter larger than the diameter of the first straight pipe 63, and an inhibitor 64 a that disturbs the flow of the liquid is contained therein. It consists of the accommodated second straight pipe 64.

Specifically, the flow pipe 60 uses the straight pipe portion 61 of the first embodiment as the first straight pipe 63, and replaces the downstream straight pipe portion 62 of the first embodiment with the second straight pipe 64. It is configured to be connected to the first straight pipe 63 (straight pipe portion 61).
Here, if the cross-sectional area of the second straight pipe portion 64 is smaller than the cross-sectional area of the first straight pipe portion 63, the flow rate of the liquid in the second straight pipe 64 becomes higher than the flow rate in the first straight pipe 63. . As a result, the residence time in the second straight pipe 64 as the temperature maintaining pipe portion is shortened. Therefore, the inner diameter of the second straight pipe 64 is such that the effective cross-sectional area through which the fluid can flow when the inhibitor 64a is accommodated therein substantially matches the cross-sectional area of the first straight pipe portion 63, or the first straight pipe It is set to be larger than the cross-sectional area of the portion 63. The second straight pipe 64 extends, for example, so as to coincide with the axis C ′ and the central axis C of the first straight pipe 63 (straight pipe portion 61), one end side is connected to the first straight pipe 63, and the other end side is An opening is formed. The inhibitor 64a is introduced from the opening on the other end side. After the inhibitor 64a is introduced, the opening on the other end side of the second straight pipe portion 64 is closed by the lid member 64b having a low relative dielectric constant. The straight pipe 64c supported by the cylindrical member 39 on the upper wall 33 side via the lid member 60a is fitted into a through hole formed in the center of the lid member 60a.

  The inhibitor 64a is, for example, a large number of particles of the same material (shown as a sphere, but may be other than a sphere), and the flow of liquid flowing in the flow pipe 60 is disturbed by the particles. The granules are formed in a size larger than the inner diameter of the straight pipe 64c supported by the first straight pipe 63 and the tubular member 39 on the upper wall 33 side via the lid member 60a. Housed and supported within.

  The inhibitor 64a is formed of a material having a relative dielectric constant lower than that of the liquid to be circulated, and has a low microwave absorption (or no absorption) material such as alumina (aluminum oxide), fluororesin, quartz, and borosilicate. It is formed from glass. The inhibitor 64a may carry a catalyst for a chemical reaction.

  If there is nothing in the second straight pipe 64, the flow of the liquid flowing through the second straight pipe 64 becomes a laminar flow, but the presence of the obstruction 64a causes turbulence in the second straight pipe 64. A flow occurs. Thereby, the stirring action of a liquid arises and the chemical reaction of a liquid is accelerated | stimulated. Furthermore, since the relative permittivity of the inhibitor 64a is different from the relative permittivity of the liquid, the electric field distribution in the second straight pipe 64 is not uniform, and the strength of the electric field decreases on average. Since the absorption of the microwave into the liquid is proportional to the square of the strength of the electric field, the absorption of the microwave in the second straight pipe 64 is smaller than the absorption of the microwave in the first straight pipe 63. On the other hand, since the obstruction is not accommodated in the first straight pipe 63, the distribution of the electric field is not disturbed and extends parallel to the direction of the electric field, so that the absorption of the microwave is large.

  According to the microwave device 100 having such a configuration, the heating pipe section is composed of the first straight pipe 63 (straight pipe section 61) extending in a direction substantially parallel to the direction of the electric field. A second straight pipe extending from the first straight pipe 63 and having a diameter larger than the diameter of the first straight pipe 63 and containing therein an inhibitor 64a having a dielectric constant lower than that of the liquid and disturbing the flow of the liquid. Since the configuration is made of the tube 64, the strength of the electric field in the second straight tube 64 can be made smaller than the strength of the electric field in the first straight tube 63 by the inhibitor 64a. Thereby, similarly to the first and second embodiments, the temperature of the liquid can be rapidly raised in the heating pipe part, and the temperature of the liquid in the temperature maintaining pipe part is a temperature not lower than the first temperature and not higher than the second temperature. The range can be maintained for a predetermined time. Therefore, as in the first and second embodiments, even if the processing amount per unit time is increased, it is possible to suppress a reduction in the time for maintaining the temperature of the liquid in a predetermined temperature range, and a sufficient yield can be obtained. Rate can be obtained.

  In the first to third embodiments, as shown in FIGS. 3, 5, and 6, the cylindrical inner diameter of the cylindrical member 39 ′ on the bottom wall 34 side is the cylindrical member 39 on the upper wall 33 side. However, the present invention is not limited to this and may be smaller than the cylinder inner diameter of the cylindrical member 39 on the upper wall 33 side. For example, the cylindrical inner diameter of the cylindrical member 39 ′ on the bottom wall 34 side can be reduced to a diameter that allows a straight pipe inserted into the cylindrical member 39 ′ to be inserted. In this case, the lid member 60a 'is unnecessary, and the end of the flow pipe 60 is directly supported by the cylindrical inner surface of the cylindrical member 39'.

  FIG. 7 is an example in which the electric field generated in the irradiation chamber 32 is simulated. 7A and 7C show simulation results when the flow pipe 60 of the first embodiment is arranged in the irradiation chamber 32, and as described above, the cylindrical member 39 ′ on the bottom wall 34 side. FIGS. 7B and 7D show a case where the cylinder inner diameter is made smaller than the downstream side serpentine tube 62 side. For simplification of the calculation, in the simulation, the relative permittivity of the flow pipe 60 itself is assumed to be negligibly small, and the number of turns of the downstream side serpentine tube portion 62 is four. 7A and 7B show the case where the liquid is acetonitrile (relative dielectric constant = 37.5 (room temperature)), and FIGS. 7C and 7D show the liquid is ethanol (relative dielectric constant). = 24.5 (room temperature)). In FIG. 7, the horizontal axis is the distance in the direction of the central axis C, the vertical axis is the distance from the central axis C in the radial direction (the direction orthogonal to the central axis), and the circles indicate the cross section of the serpentine tube of the downstream side serpentine tube portion 62. Represent.

  In FIG. 7, a line represented approximately in the horizontal direction is an electric field line, which is an electric field envelope, and the electric field is along this line. The electric field lines and electric field are slightly disturbed in the vicinity of the liquid (circles), but become a straight line substantially parallel to the central axis C. That is, the direction of the electric field generated in the irradiation chamber 32 is substantially parallel to the central axis C. As shown in FIG. 7, the smaller the inner diameter of the cylindrical member 39 ′ is (FIG. 7B and FIG. 7D), the more the electric field can be concentrated on the straight pipe portion 61. In addition, the electric field can be concentrated on the straight pipe portion 61 as the relative dielectric constant is larger (FIGS. 7A and 7B). Therefore, the liquid in the straight pipe portion 61 can be heated more rapidly as the inner diameter of the tubular member 39 ′ on the bottom wall 34 side is smaller and the relative dielectric constant of the liquid is larger.

  By the way, the liquid circulated through the circulation pipe 60 is not one type but various. Therefore, for example, after a predetermined liquid is heat-treated at a resonance frequency in the ISM band, another type of liquid having a different dielectric constant may be heat-treated. For example, when a liquid (for example, water) having a relative dielectric constant larger than that of the first liquid is circulated through the flow pipe 60, the resonance frequency of the cavity resonator 30 becomes lower than the first resonance frequency, and the lower limit of the frequency band of the ISM band. May come off beyond. On the other hand, when a liquid (for example, toluene) having a relative dielectric constant smaller than that of the first liquid is circulated through the flow pipe 60, on the contrary, the resonance frequency of the cavity resonator 30 becomes higher than the first resonance frequency, and the frequency in the ISM band. It may go beyond the upper limit of the belt. In addition, when the matching between the impedance of the cavity resonator 30 and the impedance of the waveguide 20 or the like is inappropriate, the reflection of the microwave is increased, and the absorption efficiency of the microwave is deteriorated. In these cases, preferred modifications of the first to third embodiments will be described below.

  In the first to third embodiments described above, the flow pipe 60 is described as being positioned and supported by the cylindrical members 39, 39 ′ via the lid members 60, 60 ′. The position in the container 30 may be adjustable. Specifically, although not shown in the figure, it further includes a position adjusting means capable of adjusting the position of the flow pipe 60 in the cavity resonator 30.

  FIG. 8 is a conceptual diagram for explaining the position adjustment of the flow pipe 60 in the cavity resonator 30, and shows the case of the flow pipe 60 of the first embodiment as an example. The flow pipe 60 is, for example, positioned by means of position adjustment (not shown), for example, an axial direction along the axis C ′ (center axis C) of the straight pipe portion 61 and a direction orthogonal to the axis C ′ (hereinafter referred to as “radial direction”). It is supported in a state where movement can be adjusted.

  Here, when the flow pipe 60 moves in the axial direction, the position of the boundary part Z between the straight pipe part 61 and the downstream side serpentine pipe part 62 (that is, the boundary part between the heating pipe part and the temperature maintaining pipe part) is the cavity. Moves up and down in the resonator 30. Here, the straight pipe portion 61 has a stronger effect of lowering the resonance frequency of the cavity resonator 30 than the downstream side serpentine portion 62. For this reason, in FIG. 8, when the position of the boundary Z moves upward and the proportion (configuration ratio) of the straight pipe portion 61 in the cavity resonator 30 increases, the resonance frequency of the cavity resonator 30 increases. On the contrary, when the position of the boundary portion Z moves downward and the proportion of the straight pipe portion 61 in the cavity resonator 30 decreases, the resonance frequency of the cavity resonator 30 increases.

  Therefore, by configuring the axial position of the flow pipe 60 in the cavity resonator 30 so as to be adjustable, the resonance frequency of the cavity resonator 30 is set according to the type of liquid to be circulated, that is, the relative dielectric constant. It can be adjusted to fall within the ISM band. As described above, the microwave is configured to be output from the variable frequency oscillator 11 using a solid element. However, when the resonant frequency is configured to be adjustable as described above, the microwave oscillator is configured to output the microwave. Not limited to. In this case, since it is not necessary to sweep the microwave frequency over a wide range, a microwave oscillator having a narrow frequency sweep width such as a magnetron used in a microwave oven can be used.

  In addition, as shown in FIG. 8, the impedance of the cavity resonator 30 can be adjusted by configuring the radial position and the axial position of the flow pipe 60 in the cavity resonator 30 to be adjustable. it can. Thereby, impedance can be adjusted and the reflected wave of a microwave can be decreased. For example, as shown in FIG. 8, the position adjusting means is configured so that the entire flow pipe 60 can also be translated in the radial direction while the axis C ′ and the spiral center are parallel to the central axis C. Adjust the position in the radial direction. In this case, the tubular member 39 on the upper wall side and the tubular member 39 ′ on the bottom wall side are configured to support the flow pipe 60 so that the flow pipe 60 can move in the axial direction and the parallel movement. .

  In addition, as shown in FIG. 8, the connection location with the straight pipe part 61 of the downstream side serpentine pipe part 62 and the connection place with the straight pipe on the upper wall 33 side of the downstream side serpentine pipe part 62 are aligned with the central axis C. However, the present invention is not limited to this, and the center axis C may be decentered. For example, as shown in FIG. 9, the connection location between the downstream side serpentine tube portion 62 and the straight pipe portion 61 and the downstream side serpentine tube portion 62 on the upper wall 33 side are connected to the central axis C. Each may be set on an axis C ″ that is eccentric according to the winding outer diameter of the snake tube. That is, the spiral center of the downstream side serpentine tube portion 62 is aligned with the central axis C, and the straight tube portion 61 and the straight tube on the upper wall 33 side are extended along the axis C ″ that is eccentric with respect to the central axis C. In this case, the radial position adjustment of the flow pipe 60 may be performed by rotating the flow pipe 60 about the axis C ″ as shown in FIG. Thereby, since it is possible to adjust the position in the radial direction without moving the flow pipe 60 in parallel, the structure of each cylindrical member 39, 39 ′ that supports both ends of the flow pipe 60 can be simplified. . Moreover, when it is set as the structure which adjusts the position of the radial direction of the flow pipe 60 by rotation of both ends, the structure which makes small the cylinder internal diameter of cylindrical member 39 'mentioned above to the diameter which can insert the straight pipe part 61 is possible. Can be adopted. Moreover, although this modification which comprised the position of the flow pipe 60 adjustable was demonstrated taking the flow pipe 60 of 1st Embodiment as an example, the flow pipe 60 is the structure shown in 2nd and 3rd embodiment. It may be.

  FIG. 10 shows an example of the measurement result of the resonance frequency when the composition ratio of the heating pipe section (straight pipe section 61) and the temperature maintenance pipe section (downstream serpentine pipe section 62) in the cavity resonator 30 is changed. Is shown. The height H (see FIG. 2) of the cavity resonator 30 (irradiation chamber 32) is 50 mm, the dimension L (see FIG. 2) in the width direction of the irradiation chamber 32 is 79 mm, and the straight pipe portion 61 and the downstream side serpentine portion 62 The outer diameter of the tube is 6 mm, the inner diameter is 3.6 mm, the outer diameter of the downstream side serpentine tube portion 62 is 20 mm, the winding pitch is 12.5 mm, and the downstream side serpentine tube portion 62 has four types of windings, 1 to 4. Measured in case. From this measurement result, as the overall length of the flow pipe 60 is made constant and the proportion of the length of the straight pipe portion 61 occupying the whole is increased, the resonance frequency becomes lower and the proportion of the length of the straight pipe portion 61 is increased. It can be seen that the lower the value, the higher the resonance frequency. For this reason, a plurality of flow pipes 60 having different ratios of the heating pipe part and the temperature maintaining pipe part in the cavity resonator 30 are prepared so that they can be detachably attached to the cavity resonator 30. The resonance frequency can also be adjusted by configuring the position of the flow pipe 60 in the cavity resonator 30 to be adjustable. In this case, it is not necessary to provide the position adjusting means.

  In the first to third embodiments and the modifications thereof, the cavity resonator 30 has been described as being configured to include the irradiation chamber 32 of a square columnar cavity as shown in FIG. Although not limited to this, although not shown in the drawings, a cylindrical cavity irradiation chamber may be provided. The dimension L of the irradiation chamber 32 in FIG. 2 corresponds to the diameter of the irradiation chamber of this cylindrical cavity. In this case, since the irradiation chamber is a cylindrical cavity, the electromagnetic field in the TM010 mode is excited if nothing is contained in the cavity resonator. When the frequency of the resonating microwave is 2,450 MHz, the diameter L when there is nothing in the irradiation chamber is 93.7 mm. As in the first embodiment, an error of about ± several percent with respect to L is allowed.

  Moreover, the flow pipe 60 in the first to third embodiments and the modified examples thereof is also a flow pipe according to the present invention. According to the flow pipes 60 of these embodiments, the heating pipe part for raising the temperature of the liquid to the first temperature, and the temperature of the liquid flowing through the heating pipe part are changed from the first temperature to the first temperature. Since it is configured to include the temperature maintaining pipe portion for maintaining within the higher second temperature range, the heating flow pipe structure and the temperature maintaining flow pipe structure can be constructed separately. Therefore, if a flow pipe structure for heating and temperature maintenance is appropriately constructed and disposed in the irradiation chamber 32 of the microwave device 100, a sufficient yield can be obtained even if the throughput per unit time is increased. Can be provided.

10 .... Microwave generator 30 ... Cavity resonator 32 ... Irradiation chamber (cavity)
33 ··· Upper wall 34 ······ Bottom wall 39, 39 '··· Cylindrical member 60 ······· Distribution pipe 61 ······ Straight pipe portion Pipe)
61 ′ ・ ・ ・ ・ ・ Upstream side serpentine section (heating pipe section)
62, 62 '... downstream side serpentine part (temperature maintaining pipe part)
63 ······ 1st straight pipe (heating pipe)
64 ······ 2nd straight pipe (temperature maintaining pipe)
64a... Obstacle means 100... Microwave device

Claims (10)

In the microwave device that arranges the flow pipe in the cavity resonator that resonates the microwave, and heats the liquid flowing in the flow pipe,
The flow pipe has a heating pipe part for raising the temperature of the liquid to the first temperature, and a temperature of the liquid flowing through the heating pipe part from the first temperature to the second higher than the first temperature. A microwave device comprising: a temperature maintaining tube portion for maintaining within a temperature range.   The angle formed by the direction of the single-mode electric field generated in the cavity resonator due to the resonance of the microwave and the flow direction of the liquid in the heating tube is determined by the direction of the electric field and the temperature maintaining tube. The microwave device according to claim 1, wherein the microwave device is smaller than an angle formed by a flow direction of the liquid in the liquid crystal. The heating tube portion is a straight tube extending in a direction substantially parallel to the direction of the electric field,
The microwave device according to claim 2, wherein the temperature maintaining tube portion is a serpentine tube extending spirally from the straight tube.   4. The microwave device according to claim 3, wherein the angle of the temperature maintaining pipe section is set so as to increase toward a downstream side of the liquid flow. 5.   The microwave device according to claim 2, wherein each of the heating tube portion and the temperature maintaining tube portion is a serpentine tube.   The microwave device according to claim 5, wherein the angle of at least one of the heating tube portion and the temperature maintaining tube portion is set so as to increase toward a downstream side of the liquid flow. The heating tube portion is composed of a first straight tube extending in a direction substantially parallel to the direction of the electric field,
The temperature maintaining pipe portion is a straight pipe extending from the first straight pipe and having a diameter larger than the diameter of the first straight pipe, and has a relative dielectric constant lower than that of the liquid therein and the flow of the liquid. The microwave device according to claim 1, comprising a second straight pipe containing an obstruction that disturbs.   The microwave device according to claim 1, wherein the position of the flow pipe in the cavity resonator is adjustable. A cylindrical member is disposed on each of the upper wall and the bottom wall of the cavity resonator so that the inside of the cylindrical member communicates with the cavity in the cavity resonator. It is configured to support both ends of the flow pipe,
The microwave device according to any one of claims 1 to 8, wherein a cylindrical inner diameter of the cylindrical member on the heating tube portion side is smaller than a cylindrical inner diameter of the cylindrical member of the temperature maintaining tube portion. A microwave device comprising a cavity resonator for resonating microwaves, a flow pipe disposed in the cavity resonator for circulating a liquid,
The heating pipe part for raising the temperature of the liquid to the first temperature and the temperature of the liquid flowing through the heating pipe part are within the range of the second temperature higher than the first temperature from the first temperature. A flow pipe including a temperature maintaining pipe part for maintaining.