JP7061819B1 - Microwave leakage detection method, microwave leakage detection device, and sensor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microwave leakage detection device used in an explosion-proof area. SOLUTION: A microwave leakage detection device 1 detects an increase in at least one of an electric field and a magnetic field by an explosion-proof sensor 10a having an explosion-proof structure capable of detecting an increase in at least one of an electric field and a magnetic field, and an explosion-proof sensor 10a. A detection unit 20 for detecting the leakage of microwaves is provided accordingly. The explosion-proof sensor 10 is an inductive explosion-proof proximity sensor and has a detection coil 11 and an internal circuit 12. [Selection diagram] Fig. 1

Description

The present invention relates to a leak detection method and a leak detection device for detecting microwave leakage, and a sensor device used therein.

In the process of handling flammable gas, vapor, dust, etc., the area where electronic devices can be used is usually defined as an explosion-proof area. This is because the electronic device becomes an ignition source and may cause an explosion. Therefore, in the explosion-proof area, an electronic device having an explosion-proof structure is used so as not to be an ignition source.

The microwave irradiation process may take place within the explosion-proof area. In such a case, there is a desire to detect microwave leakage, but at present, sensors having an explosion-proof structure capable of detecting microwave leakage are not widely available, and microwaves can be detected in an explosion-proof area. There is a problem that it is difficult to detect the leakage of microwaves during irradiation.

The present invention has been made in view of such problems, and an object thereof is microwave leakage detection for detecting microwave leakage when irradiating microwaves in an explosion-proof area. To provide methods and microwave leak detection devices, as well as sensor devices used in them.

In order to achieve the above object, the microwave leakage detection method according to one aspect of the present invention has an explosion-proof structure capable of detecting an increase in at least one of an electric field and a magnetic field at a location where microwave leakage is desired to be detected in an explosion-proof area. Detects microwave leakage in response to detecting an increase in at least one of the electric and magnetic fields by the step of placing one or more explosion-proof sensors and at least one of the one or more explosion-proof sensors. Steps to do, and include.

Further, in the microwave leakage detection method according to one aspect of the present invention, the explosion-proof sensor is an inductive, capacitive, or magnetic explosion-proof proximity sensor, and in the step of detecting microwave leakage, the explosion-proof sensor. Microwave leakage may be detected when the output of is the output corresponding to the object detection.

Further, in the microwave leakage detection method according to one aspect of the present invention, in the step of arranging the explosion-proof sensor, one or two or more explosion-proof sensors are joined to the flange of the hollow member having a space for introducing the microwave. In the step of arranging in the unit and detecting the leakage of the microwave, the leakage of the microwave may be detected when the microwave is introduced into the space.

Further, in the microwave leakage detection method according to one aspect of the present invention, in the step of arranging the explosion-proof sensor, one or two or more explosion-proof sensors are placed on the microwave from the inside to the outside of the container to which the microwave is irradiated. In the step of detecting microwave leakage by arranging it on the outside of the choke structure to prevent wave leakage, even if microwave leakage is detected while microwaves are being irradiated inside the container. good.

Further, in the leakage detection method according to one aspect of the present invention, the explosion-proof sensor has directivity, and in the step of arranging the explosion-proof sensor, one or two or more explosion-proof sensors are leaked in the direction of microwaves. May be arranged so that it can be detected.

The microwave leakage detection device according to one aspect of the present invention corresponds to an explosion-proof sensor having an explosion-proof structure capable of detecting an increase in at least one of an electric field and a magnetic field, and a detection of an increase in at least one of an electric field and a magnetic field by the explosion-proof sensor. It is equipped with a detection unit that detects the leakage of microwaves.

Further, in the microwave leakage detection device according to one aspect of the present invention, the explosion-proof sensor may be an inductive type, a capacitance type, or a magnetic type explosion-proof proximity sensor.

The sensor device for detecting microwave leakage according to one aspect of the present invention is provided so as to surround the object detection range of the explosion-proof proximity sensor having an inductive, capacitive, or magnetic explosion-proof structure and the explosion-proof proximity sensor. In addition, it is provided with a protective member that transmits microwaves.

The sensor device for detecting microwave leakage according to one aspect of the present invention includes an explosion-proof sensor having an explosion-proof structure capable of detecting an increase in at least one of an electric field and a magnetic field, and a microwave-proof explosion sensor provided around the explosion-proof sensor. It is provided with a reflective member for guiding to.

Further, in the sensor device according to one aspect of the present invention, the explosion-proof sensor may be an inductive type, a capacitance type, or a magnetic type explosion-proof proximity sensor.

According to the microwave leakage detection method and the microwave leakage detection device according to one aspect of the present invention, an explosion-proof sensor capable of detecting an increase in at least one of an electric field and a magnetic field is used at a location where microwave leakage is desired to be detected in the explosion-proof area. By arranging it in the explosion-proof area, it is possible to detect the leakage of microwaves when irradiating microwaves in the explosion-proof area.

Schematic diagram showing the configuration of the microwave leakage detection device according to the embodiment of the present invention. The figure for demonstrating the experiment using the explosion-proof sensor in the same embodiment. The figure for demonstrating the experiment using the explosion-proof sensor in the same embodiment. Schematic diagram showing another configuration of the microwave leakage detection device according to the same embodiment. Schematic diagram showing another configuration of the microwave leakage detection device according to the same embodiment. Schematic diagram showing another configuration of the microwave leakage detection device according to the same embodiment. The figure which shows the sensor device which has the protective member in the same embodiment. The figure which shows the sensor device which has the reflection member in the same embodiment. The figure which shows the sensor device which has the reflection member in the same embodiment. The figure which shows the sensor device which has the protection member and the reflection member in the same embodiment. The figure which shows the sensor device which has the reflection member in the same embodiment. Sectional drawing which shows the sensor device which has the reflection member in the same embodiment. The figure for demonstrating the arrangement of the explosion-proof sensor in the same embodiment. The figure for demonstrating the arrangement of the explosion-proof sensor in the same embodiment. The figure for demonstrating the arrangement of the explosion-proof sensor in the same embodiment. The figure for demonstrating the arrangement of the explosion-proof sensor in the same embodiment. The figure for demonstrating the arrangement of the explosion-proof sensor in the same embodiment. The figure for demonstrating the arrangement of the explosion-proof sensor in the same embodiment. The figure for demonstrating the arrangement of the explosion-proof sensor in the same embodiment.

Hereinafter, a microwave leakage detection method according to one aspect of the present invention, a microwave leakage detection device, and a sensor device used therein will be described using embodiments. In the following embodiments, the components with the same reference numerals are the same or correspond to each other, and the description thereof may be omitted again. The microwave leakage detection method and the microwave leakage detection device according to the present embodiment detect microwave leakage using a sensor having an explosion-proof structure. Further, the sensor device according to the present embodiment is a device used for detecting the leakage of microwaves.

1, FIG. 3A, FIG. 3B, and FIG. 4 are schematic views showing the configuration of the microwave leakage detection device 1 according to the present embodiment. The microwave leakage detection device 1 has an explosion-proof sensor 10 having an explosion-proof structure capable of detecting an increase in at least one of an electric field and a magnetic field, and a microwave according to the fact that the explosion-proof sensor 10 detects an increase in at least one of the electric field and the magnetic field. A detection unit 20 for detecting wave leakage is provided. Note that FIG. 1 shows the explosion-proof sensor 10a which is an inductive explosion-proof proximity sensor, FIGS. 3A and 3B show the explosion-proof sensor 10b which is a capacitance type explosion-proof proximity sensor, and FIG. 4 shows the explosion-proof sensor 10b. , The explosion-proof sensor 10c, which is a magnetic explosion-proof proximity sensor, is shown. When the explosion-proof sensors 10a, 10b, and 10c are not particularly distinguished, they are referred to as explosion-proof sensors 10 as described above. The explosion-proof sensor 10 may be, for example, a sensor having a pressure-resistant explosion-proof structure, an internal pressure explosion-proof structure, a safety-enhanced explosion-proof structure, an oil-filled explosion-proof structure, or an intrinsically safe explosion-proof structure. As for the types of the pressure-resistant explosion-proof structure and the internal pressure explosion-proof structure, it is preferable to select one suitable for the type of the explosion-proof area.

In FIG. 1, the explosion-proof sensor 10a, which is an inductive explosion-proof proximity sensor, has a detection coil 11 and an internal circuit 12. When the explosion-proof sensor 10a is used as a proximity sensor, the internal circuit 12 generates a high-frequency magnetic field by the detection coil 11. Then, when a metal object approaches, an induced current (eddy current) flows in the metal object, and the impedance of the detection coil 11 changes. The internal circuit 12 can detect an object by the change in its impedance. On the other hand, as shown in FIG. 1, even when the detection coil 11 is irradiated with the microwave 5, the high frequency magnetic field is disturbed and the impedance of the detection coil 11 changes, so that the internal circuit 12 is the same as the object detection. And microwaves can be detected. That is, the detection unit 20 may detect the leakage of microwaves when the output from the explosion-proof sensor 10a becomes the output corresponding to the object detection. When the output from the explosion-proof sensor 10a becomes an output corresponding to the object detection, it means that the strength of the electromagnetic field of the microwave at the position of the detection coil 11 exceeds a certain value. Therefore, it can be said that the explosion-proof sensor 10a is a sensor capable of detecting an increase in at least one of an electric field and a magnetic field.

A microwave detection experiment was conducted using an inductive explosion-proof proximity sensor. In this experiment, as shown in FIG. 2A, the explosion-proof sensor 10a is arranged so that the distance from the junction of the flange of the waveguide is L, and the microwave leaks from the junction of the flange of the waveguide. Wave detection was performed. In FIG. 2A, the detection coil 11 shown by the broken line is located on the left side of the explosion-proof sensor 10a. In this experiment, the microwave was detected in the situation where the leakage amount of the microwave was 3 (mW / cm ² ) at the position where the distance L in FIG. 2 was 5 cm. The amount of microwave leakage was measured with a high-frequency electromagnetic field measuring instrument (display: NBM-520, probe: E0391) manufactured by Narda. As the explosion-proof sensor 10a, three proximity sensors having an explosion-proof structure with detection distances of 5 mm, 10 mm, and 15 mm manufactured by IDEC were used. The experimental results are shown in the following table.

Proximity sensors with a detection distance of 5 mm could not detect microwaves, but proximity sensors with detection distances of 10 mm and 15 mm could detect microwaves at distances L = 1 cm and 3 cm, respectively. rice field. The field strengths at those distances are as described in the table above. Further, when the explosion-proof sensor 10a was arranged as shown in FIG. 2B, microwaves could not be detected. Therefore, the explosion-proof sensor 10a used in the experiment could not detect the microwave 5 in the direction of the arrow D1 in FIG. 1, and could detect the microwave 5 in the direction of the arrow D2. Therefore, the explosion-proof sensor 10a, which is an inductive explosion-proof proximity sensor, has directivity. It was also confirmed that the longer the detection distance of the explosion-proof proximity sensor, the higher the detection sensitivity of microwaves, and the weaker the microwaves can be detected. Therefore, it is sufficient to use an explosion-proof proximity sensor with a detection distance according to the intensity of the microwave to be detected. The detection distance of the proximity sensor is the distance at which the proximity sensor operates when the standard detector is brought closer to the detection surface in the vertical direction.

In FIG. 3A, the explosion-proof sensor 10b, which is a capacitance-type explosion-proof proximity sensor, has an electrode 13 and an internal circuit 14. When the explosion-proof sensor 10b is used as a proximity sensor, the internal circuit 14 has, for example, a high-frequency oscillation circuit, and when an object such as a dielectric approaches, the charge of the electrode 13 changes and changes accordingly. The object can be detected by the oscillating state. On the other hand, as shown in FIG. 3A, even when the electrode 13 is irradiated with microwaves, the electric charge of the electrode 13 changes. Therefore, the internal circuit 14 transmits the microwaves in the same manner as in the object detection. Can be detected. That is, the detection unit 20 may detect the leakage of microwaves when the output from the explosion-proof sensor 10b becomes the output corresponding to the object detection. When the output from the explosion-proof sensor 10b becomes an output corresponding to the object detection, it means that the strength of the microwave electric field at the position of the electrode 13 exceeds a certain value. Therefore, it can be said that the explosion-proof sensor 10b is a sensor capable of detecting an increase in at least one of an electric field and a magnetic field.

In the capacitance type explosion-proof sensor 10b, the microwave 5 in the direction of arrow D1 in FIG. 3A can change the charge at the electrode 13 more than the microwave 5 in the direction of arrow D2. Therefore, the explosion-proof sensor 10b is easier to detect the microwave 5 in the direction of the arrow D1 than the microwave 5 in the direction of the arrow D2, and has directivity.

When a microwave detection experiment was conducted using a capacitance type explosion-proof proximity sensor, a metal plate was found to face the electrode 13 as shown in FIG. 3B rather than the configuration shown in FIG. 3A. The configuration in which 23 was arranged had higher microwave detection sensitivity and was able to detect weaker microwaves. The metal plate 23 is usually a flat plate, and it is preferable that the metal plate 23 has the same size as the electrode 13 or is larger than the electrode 13. In this case, the explosion-proof sensor 10b may have an electrode 13, an internal circuit 14, and a metal plate 23 provided so as to face the electrode 13, as shown in FIG. 3B. The metal plate 23 is arranged on the object detection side of the proximity sensor with respect to the electrode 13. In the explosion-proof sensor 10b shown in FIG. 3B, the microwave traveling in the normal direction with respect to the plane of the electrode 13 or the metal plate 23 is shielded by the metal plate 23 and does not reach the electrode 13, so that it is in the direction of the arrow D2. The microwave 5 will be detected. Therefore, the explosion-proof sensor 10b shown in FIG. 3B also has directivity.

In FIG. 4, the explosion-proof sensor 10c, which is a magnetic explosion-proof proximity sensor, has a hall IC 15 and an internal circuit 16. When the explosion-proof sensor 10c is used as a proximity sensor, when an object that generates a magnetic field (for example, a permanent magnet) approaches, the magnetic field generates a Hall voltage in the Hall IC 15. The internal circuit 16 can detect an object by amplifying and detecting the Hall voltage. On the other hand, as shown in FIG. 4, even when the hall IC 15 is irradiated with the microwave 5, the hall voltage is generated in the hall IC 15 by the magnetic field of the microwave 5, so that the internal circuit 16 is the same as the object detection. The microwave 5 can be detected. That is, the detection unit 20 may detect the leakage of microwaves when the output from the explosion-proof sensor 10c becomes the output corresponding to the object detection. When the output from the explosion-proof sensor 10c becomes an output corresponding to the object detection, it means that the strength of the microwave magnetic field at the position of the hall IC 15 exceeds a certain value. Therefore, it can be said that the explosion-proof sensor 10c is a sensor capable of detecting an increase in at least one of an electric field and a magnetic field.

Here, the case where the explosion-proof sensor 10c is an explosion-proof proximity sensor equipped with a Hall IC15 which is a Hall element has been described. However, the explosion-proof sensor 10c is an explosion-proof proximity sensor equipped with a magnetoresistive element instead of the Hall IC15. May be good. In this case, microwaves may be detected according to the increase in the resistance of the magnetoresistive element. Since the magnetic field in one direction is detected in the Hall IC 15, the explosion-proof sensor 10c using the Hall IC 15 has directivity. On the other hand, since the increase in the magnetic field at the detection position is detected by the magnetoresistive element, the explosion-proof sensor 10c using the magnetoresistive element does not have directivity, and the microwave 5 in the direction of the arrow D1 is also indicated by the arrow D2. The directional microwave 5 can also be detected. Further, even if the explosion-proof sensor 10c uses the Hall IC 15, if the configuration can cover a plurality of detection directions, for example, when a plurality of Hall IC 15s are used, the explosion-proof sensor 10c has no directivity. can do.

Since the explosion-proof sensors 10a, 10b, and 10c, which are inductive, capacitive, or magnetic explosion-proof proximity sensors, are already on the market, detailed description thereof will be omitted. Further, the frequency of the microwave detected by using the explosion-proof sensor 10 may be, for example, in the vicinity of 915 MHz, 2.45 GHz, 5.8 GHz, 24 GHz, and other frequencies in the range of 300 MHz to 300 GHz. You may.

The explosion-proof sensor 10 having an explosion-proof structure capable of detecting an increase in at least one of an electric field and a magnetic field may be a sensor whose output changes when the intensity of microwaves at the sensing position exceeds a threshold value. If the threshold can be adjusted, the threshold may be calibrated before arranging the explosion-proof sensor 10 so that the leakage of microwaves of a desired intensity can be detected. On the other hand, when the explosion-proof sensor 10, which is a commercially available explosion-proof proximity sensor, is used, it is usually difficult to perform calibration. In this case, the leakage of microwaves of a desired intensity may be detected by adjusting the distance between the location where the microwaves leak and the explosion-proof sensor 10. For example, when detecting microwaves leaking from a junction of a waveguide flange, a weaker microwave leakage can be detected by arranging the explosion-proof sensor 10 at a position closer to the junction. By arranging the explosion-proof sensor 10 at a position farther from the joint portion, it becomes possible to detect the leakage of the microwave when the intensity of the leaking microwave is higher.

The detection unit 20 detects the leakage of microwaves in response to the detection of an increase in at least one of the electric field and the magnetic field by the explosion-proof sensor 10. When the explosion-proof sensor 10 is an explosion-proof proximity sensor, the detection unit 20 may detect microwave leakage when the output of the explosion-proof sensor 10 becomes an output corresponding to the object detection. The detection of microwave leakage by the detection unit 20 may mean, for example, outputting the detection result by a predetermined method, and when the detection of microwave leakage is detected, a predetermined control or the like may be used. It may be to perform the processing of. The output of the detection result may be, for example, display of the detection result, sound output, transmission, or the like. Further, when performing processing such as control, for example, when a microwave leak is detected, the detection unit 20 stops the generation of microwaves by the microwave generator in order to stop the irradiation of microwaves. Control may be performed. The explosion-proof sensor 10 is usually arranged in an explosion-proof area. On the other hand, the detection unit 20 is usually arranged outside the explosion-proof area. As described above, when the detection unit 20 is arranged outside the explosion-proof area, the detection unit 20 does not have to have an explosion-proof structure. Further, FIGS. 1, 3A, 3B, and 4 show a case where one explosion-proof sensor 10 is connected to the detection unit 20, but two or more explosion-proof sensors 10 are connected to the detection unit 20. Needless to say, it may be done. Therefore, the microwave leakage detection device 1 may have two or more explosion-proof sensors 10. When two or more explosion-proof sensors 10 are connected to the detection unit 20, the detection unit 20 has detected an increase in at least one of the electric field and the magnetic field by at least one of the two or more explosion-proof sensors 10. Depending on the situation, microwave leakage may be detected.

Next, the sensor device 8 according to the present embodiment will be described. FIG. 5 is a diagram showing a sensor device 8 having a protective member 30 provided in the object detection range 31 of the explosion-proof sensor 10. FIGS. 6A to 6C, FIGS. 7A, and 7B show microwaves to the explosion-proof sensor 10. It is a figure which shows the sensor device 8 which has the reflection member 40 for guiding. In the microwave leakage detection device 1, the sensor device 8 may be used instead of the explosion-proof sensor 10.

In FIG. 5, the sensor device 8 has an explosion-proof sensor 10 and a protective member 30. The explosion-proof sensor 10 may be, for example, the explosion-proof proximity sensor described above. The protective member 30 is provided so as to surround the object detection range 31 of the explosion-proof sensor 10. The protective member 30 is for preventing an object from entering the object detection range 31. Therefore, it is preferable that the protective member 30 is provided so as to surround the entire object detection range 31. Further, when the protective member 30 is made of a material detected by the explosion-proof sensor 10, the protective member 30 has an object detection range in order to prevent the protective member 30 from being detected by the explosion-proof sensor 10. It is preferable that it does not exist in 31. On the other hand, when the protective member 30 is made of a material that is not detected by the explosion-proof sensor 10, the protective member 30 may be present within the object detection range 31. The protective member 30 is provided so as to surround the object detection range 31 of the explosion-proof sensor 10. Thus, the protective member 30 made of a material not detected by the explosion-proof sensor 10 is within the object detection range 31. It is a concept that includes existence. By providing the protective member 30, the explosion-proof sensor 10 can detect microwaves instead of detecting an approaching object. Further, in order to detect microwaves by the explosion-proof sensor 10, it is preferable that the protective member 30 is made of a material that transmits microwaves. The material that transmits microwaves is a material having a small specific dielectric loss and is not particularly limited, but may be, for example, a fluororesin such as polytetrafluoroethylene, quartz, glass, ceramic, resin or the like. .. The specific dielectric loss of the microwave transmissive material is preferably less than 1, and more preferably less than 0.1, for example, at the frequency of the microwave to be detected and the temperature at which leakage is detected. , 0.01 is more preferred.

In FIG. 6A, the sensor device 8 has an explosion-proof sensor 10 and a reflection member 40a for guiding the microwave 5 to the explosion-proof sensor 10. The reflective member 40a is provided around the explosion-proof sensor 10 and may have a horn shape as shown in FIG. 6A.

In FIG. 6B, the sensor device 8 has an explosion-proof sensor 10 and a reflection member 40b for guiding the microwave 5 to the explosion-proof sensor 10. The reflective member 40b is provided around the explosion-proof sensor 10 and may have a parabolic shape as shown in FIG. 6B. When the reflective members 40a and 40b are not particularly distinguished, they are referred to as the reflective member 40 as described above. The same applies to other reflective members.

The reflective member 40 may be made of, for example, a microwave reflective material. The microwave reflective material may be, for example, a metal. The metal is not particularly limited, and may be, for example, stainless steel, carbon steel, aluminum, aluminum alloy, nickel, nickel alloy, copper, copper alloy, or the like.

In this way, by using the reflective member 40, the microwave 5 can be reflected and guided to the directional explosion-proof sensor 10 such as an inductive explosion-proof proximity sensor, and the direction is different from the directivity. It will be possible to detect microwaves as well.

In FIG. 6C, the sensor device 8 includes an explosion-proof sensor 10, a protective member 30, and a reflective member 40a. As described above, the sensor device 8 may have both the protective member 30 and the reflective member 40.

7A and 7B are diagrams showing a sensor device 8 having a rectangular parallelepiped-shaped reflective member 40c having an open surface and an explosion-proof sensor 10 arranged inside the reflective member 40c. 7A is a view of the sensor device 8 seen from the opening 41 side, and FIG. 7B is a sectional view taken along line VIIB-VIIB of FIG. 7A. In FIG. 7B, the internal structure of the explosion-proof sensor 10 is omitted. The reflective member 40c may also be made of the above-mentioned microwave reflective material. It is preferable that the explosion-proof sensor 10 is arranged inside the reflective member 40c so that the reflective member 40c does not exist in the object detection range 31. In this sensor device 8, the microwave introduced inside from the opening 41 is reflected on the inner surface of the reflecting member 40c and is detected by the explosion-proof sensor 10.

Next, a microwave leakage detection method using the microwave leakage detection device 1 will be described. The microwave leakage detection method includes a step of arranging one or two or more explosion-proof sensors 10 at a location where microwave leakage is desired to be detected in the explosion-proof area, and at least one or two or more explosion-proof sensors 10. It comprises the step of detecting microwave leakage in response to detecting an increase in at least one of an electric field and a magnetic field by either.

First, in the step of arranging the explosion-proof sensor 10, one or two or more explosion-proof sensors 10 are arranged at a place where microwave leakage is desired to be detected in the explosion-proof area. When the explosion-proof sensor 10 has directivity, it is preferable to arrange one or more explosion-proof sensors 10 so as to be able to detect microwaves in the direction of leakage.

The location where microwave leakage is desired to be detected may be, for example, a joint portion of a flange of a hollow member having a space in which microwaves are introduced. This is because if the joint at the joint of the flange is not properly joined, microwaves may leak from the joint. The hollow member having a space into which microwaves are introduced may be, for example, a waveguide, a container in which microwave irradiation is performed internally, or a connection tube connected to the container. It may be another hollow member having a space into which microwaves are introduced. The connecting pipe may be, for example, a viewing window, an input port for raw materials, a discharge port for products, a cleaning line, an intake port, an exhaust port, or the like.

In this case, one or more explosion-proof sensors 10 may be arranged at the joint portion of the flange of the hollow member having a space for introducing microwaves. Placing the explosion-proof sensor 10 at the flange joint may mean, for example, arranging the explosion-proof sensor 10 around the flange joint, and the explosion-proof sensor 10 is placed in the hollow portion provided at the flange joint. It may be arranged. Here, the former will be described with reference to FIGS. 8A to 8C, and the latter will be described with reference to FIG.

8A and 8B are diagrams showing an example in which four explosion-proof sensors 10 are arranged around the joint portion 50 of the flanges 51a and 52a of the waveguides 51 and 52. 8A is a view of the waveguides 51 and 52 viewed from a direction perpendicular to the central axis of the waveguides 51 and 52, and FIG. 8B is a sectional view taken along line VIIIB-VIIIB of FIG. 8A. As shown in FIGS. 8A and 8B, the flange 51a of the circular waveguide 51 and the flange 52a of the circular waveguide 52 are connected by a bolt 53 and a nut 54. Further, four attachments 55 are fixed to the flange 51a by some bolts 53, and the explosion-proof sensor 10 is fixed to the attachments 55. It is considered that the microwave leaking from the joint portion 50 of the flanges 51a and 52a travels in the direction along the joint surface. Therefore, when the explosion-proof sensor 10 is an inductive explosion-proof proximity sensor, it is directional, so that it is preferable to arrange the explosion-proof sensor 10 as shown in FIGS. 8A and 8B. That is, it is preferable that the explosion-proof sensor 10 is arranged so that the leaking microwave is in the direction indicated by the arrow D2 in FIG. Further, as shown in FIG. 8B, the four explosion-proof sensors 10 are arranged at uniform angles, that is, every 90 degrees, about the central axis in the longitudinal direction of the waveguides 51 and 52. Is preferable. Therefore, when arranging the three explosion-proof sensors 10, it is preferable to arrange them at intervals of 120 degrees around the central axes of the waveguides 51 and 52, as shown in FIG. 8C. be. As described above, when arranging the plurality of explosion-proof sensors 10 around the joint portion of the flange, it is preferable to arrange them so as to have a uniform angle with the central axis of the flange as the center.

The number of explosion-proof sensors 10 arranged around the joint portion 50 of the flanges 51a and 51b does not matter. For example, two explosion-proof sensors 10 may be arranged around the joint portion 50 of the flanges 51a and 51b, or five or more explosion-proof sensors 10 may be arranged. Since it is usually not known in advance at which position of the joint 50 the microwave leaks, the explosion-proof sensor 10 is arranged so that the leaked microwave can be detected from any position of the joint 50. Is preferable. Further, when the distance between the explosion-proof sensor 10 and the joint portion 50 to be arranged is short, more explosion-proof sensors 10 may be arranged, and when the distance is long, less explosion-proof sensors 10 are arranged. You may.

FIG. 9 is a diagram showing an example in which the explosion-proof sensor 10 is arranged in the hollow portion 56 provided in the joint portion 50 of the flanges 51a and 52a of the waveguides 51 and 52. In FIG. 9, bolts and nuts used for fixing the flanges 51a and 52a are omitted. A plurality of hollow portions 56 (for example, three, four, etc.) may be provided at equal angles about the central axes of the waveguides 51 and 52. Then, one explosion-proof sensor 10 may be arranged in each hollow portion 56. Although omitted in FIG. 9, the wiring for the output of the explosion-proof sensor 10 may extend to the outside of the waveguides 51 and 52 through the wiring holes provided in the joint portion 50 or the flange 51a. ..

Further, the place where the microwave leakage is desired to be detected may be, for example, an installation position of a choke structure for preventing the microwave leakage from the inside to the outside of the container to which the microwave irradiation is performed. This is because if the choke structure does not function properly, microwaves may leak from the choke structure. In this case, even if one or more explosion-proof sensors 10 are arranged on the outer side of the choke structure for preventing the leakage of microwaves from the inside of the container to which the microwave is irradiated to the outside. good. The choke structure may be provided, for example, in the gap between the container to which microwave irradiation is performed and the stirring shaft extending from the outside to the inside of the container, and the container to which microwave irradiation is performed and the container are opened and closed. It may be provided in a gap between the door or the shutter which is provided as possible.

FIG. 10 is a cross-sectional view showing an example of a container 61 in which microwave irradiation is performed inside and a stirring shaft 62 extending inward from the outside of the container 61. In FIG. 10, it is assumed that a choke structure is provided in the gap 63 between the boss portion 61a of the container 61 and the stirring shaft 62. A plurality of explosion-proof sensors 10 are provided on the outer side of the choke structure.

Although the case where a plurality of explosion-proof sensors 10 are arranged has been mainly described here, one explosion-proof sensor 10 may be arranged. When one explosion-proof sensor 10 is arranged, the reflective member 40 may be used in order to appropriately detect the leakage of microwaves from the joint portion of the flange or the like. 11A and 11B are views showing a situation in which one explosion-proof sensor 10 and a cylindrical reflective member 40d are arranged around the joint portion of the flanges 51a and 52a. 11A is a view of the waveguides 51 and 52 viewed from a direction perpendicular to the central axis of the waveguides 51 and 52, and FIG. 11B is a sectional view taken along line XIB-XIB of FIG. 11A. In FIGS. 11A and 11B, the attachment for attaching the reflective member 40d to the waveguides 51 and 52 is not shown. As shown in FIGS. 11A and 11B, a cylindrical shape is formed around the junction of the flanges 51a and 52a of the waveguides 51 and 52 so that the central axis coincides with the central axis of the waveguides 51 and 52. Reflective member 40d is arranged. Therefore, the microwave leaked at any of the joints of the flanges 51a and 52a is reflected by the inner peripheral surface of the cylindrical reflecting member 40d or the outer peripheral surface of the waveguides 51 and 52 to prevent one explosion. It is guided to the sensor 10 and detected by the explosion-proof sensor 10. In this way, the number of explosion-proof sensors 10 can be reduced by appropriately arranging the reflective members 40.

Next, in the step of detecting microwave leakage, microwave leakage is detected in response to detection of an increase in at least one of an electric field and a magnetic field by at least one of one or two or more explosion-proof sensors 10 arranged. Is detected. This step may be performed while the microwave irradiation process is taking place. That is, when the microwave is introduced into the internal space of the hollow member, or when the microwave is irradiated in the container provided with the choke structure, the leakage of the microwave is detected. May be good. The detection of this microwave leakage may be performed by, for example, the detection unit 20. Further, in the step of detecting the leakage of microwaves, when the increase of at least one of the electric field and the magnetic field is detected by at least one of the explosion-proof sensors 10, for example, it may be output that there is a leakage of microwaves. Alternatively, a process for dealing with microwave leakage, such as a process for stopping the microwave generator, may be performed.

As described above, according to the microwave leakage detection device 1 and the microwave leakage detection method according to the present embodiment, a commercially available explosion-proof sensor 10 capable of detecting an increase in at least one of an electric field and a magnetic field is used. This makes it possible to detect microwave leakage in the explosion-proof area at low cost. Then, the irradiation of the microwave can be stopped according to the detection of the leakage of the microwave, and the operator can evacuate from the explosion-proof area, so that the safety can be enhanced. For example, by arranging the explosion-proof sensor 10 at the joint portion of the flange, it is possible to detect the leakage of microwaves from the joint portion. Further, for example, by arranging the explosion-proof sensor 10 on the outer side of the choke structure, it is possible to detect the leakage of microwaves from the portion of the choke structure.

Further, in the sensor device 8 according to the present embodiment, by having the protective member 30 provided in the sensing range of the explosion-proof sensor 10, it is possible to prevent the explosion-proof sensor 10 from performing sensing other than microwaves. It is possible to prevent false detection other than microwaves. Further, when the sensor device 8 has a reflecting member 40 that guides microwaves to the explosion-proof sensor 10, for example, the direction of directionality may be changed, or microwave leakage may occur with a smaller number of sensor devices 8. Can be detected, or the range in which microwave leakage can be detected by one sensor device 8 can be widened.

In the present embodiment, the case where the explosion-proof sensor 10 is an explosion-proof proximity sensor has been mainly described, but it may not be the case. The explosion-proof sensor 10 may be a sensor having an explosion-proof structure other than the explosion-proof proximity sensor, which can detect an increase in at least one of an electric field and a magnetic field.

Further, the present invention is not limited to the above embodiments, and various modifications can be made, and it goes without saying that these are also included in the scope of the present invention.

1 Leakage detection device 8 Sensor device 10, 10a, 10b, 10c Explosion-proof sensor 20 Detection unit 30 Protective member 40, 40a, 40b, 40c, 40d Reflective member

Claims (7)

One of the explosion-proof structures that can detect the increase of at least one of the electric field and the magnetic field at the joint of the flange of the hollow member having the space where the microwave is introduced, which is the place where the leakage of the microwave is desired to be detected in the explosion-proof area. Or the step of arranging two or more explosion-proof proximity sensors,
A method for detecting microwave leakage, comprising a step of detecting microwave leakage in response to detecting an increase in at least one of an electric field and a magnetic field by at least one of the one or more explosion-proof proximity sensors. At least the electric field and magnetic field on the outside of the choke structure to prevent the leakage of microwaves from the inside to the outside of the container to which the microwave is irradiated, which is the place where the leakage of microwaves is to be detected in the explosion-proof area. With the step of placing one or more explosion-proof proximity sensors with an explosion-proof structure capable of detecting one increase,
A method for detecting microwave leakage, comprising a step of detecting microwave leakage in response to detecting an increase in at least one of an electric field and a magnetic field by at least one of the one or more explosion-proof proximity sensors. The leak detection method according to claim 1 or 2 , wherein the explosion-proof proximity sensor has directivity. An explosion-proof proximity sensor with an explosion-proof structure that can detect an increase in at least one of the electric and magnetic fields,
A detection unit for detecting microwave leakage in response to detection of an increase in at least one of an electric field and a magnetic field by the explosion-proof proximity sensor is provided .
The explosion-proof proximity sensor is a microwave leakage detection device arranged at a joint portion of a flange of a hollow member having a space for introducing microwaves in an explosion-proof area . An explosion-proof proximity sensor with an explosion-proof structure that can detect an increase in at least one of the electric and magnetic fields,
A detection unit for detecting microwave leakage in response to detection of an increase in at least one of an electric field and a magnetic field by the explosion-proof proximity sensor is provided.
The explosion-proof proximity sensor is a microwave leakage detection device arranged on the outside of a choke structure for preventing leakage of microwaves from the inside to the outside of a container to which microwave irradiation is performed in an explosion-proof area. The microwave leakage detection device according to claim 4 or 5 , further comprising a protective member for transmitting microwaves, which is provided so as to surround the detection range of the explosion-proof proximity sensor. The microwave leakage detection device according to any one of claims 4 to 6 , further comprising a reflective member provided around the explosion-proof proximity sensor for guiding microwaves to the explosion-proof proximity sensor.

Images