JP6456218B2 - Method for detecting combustible gas in crusher and explosion-proof device for crusher - Google Patents

Description

  The present invention relates to a flammable gas detection method for a pulverizer that detects flammable gas leaked from a container or the like contained in an object to be crushed, and to prevent the flammable gas from being ignited, burned, and exploded by a spark during crushing. The present invention relates to an explosion-proof device for a crusher.

When a material to be crushed is put into a crusher installed in a garbage incineration facility and crushed, flammable liquid and flammable gas remaining in the crushing container, such as methane, propane, butane, and gasoline, leak out. For example, Patent Document 1 has been proposed in order to prevent a spark generated during crushing from igniting and causing combustion or explosion in a crusher.
In Patent Document 1, in a crusher for crushing a material to be crushed from an upper inlet between a rotating hammer and a block protruding on a side wall surface, a gas concentration is formed on the back surface of the side wall surface. A gas meter is disclosed in which a non-combustible gas is injected to prevent combustion or explosion when a combustible gas with a concentration exceeding a standard is detected in the gas concentration meter.

  Patent Document 2 discloses an infrared gas detection device that detects a predetermined gas to be measured using an infrared light source and an infrared detection element.

Japanese Patent No. 4737838 JP 2006-220625 A

  However, since the crusher of Patent Document 1 is a gas sampling type, the response time is long for detection and the response characteristics are low. Further, since the sampling position is limited, only combustible gas generated in the vicinity of the sampling position can be detected.

  In Patent Document 2, the radiant intensity of absorbed light absorbed by the gas to be measured and the radiant intensity of reference light that is not absorbed by the gas to be measured are measured. The radiant intensity of absorbed light is based on the radiant intensity of the reference light. It is what. However, it is difficult to detect combustible gas in a space where a material to be crushed or dust is mixed, such as a crusher.

  The present invention is a method for detecting a combustible gas in a crusher capable of accurately detecting only a combustible gas by identifying the material to be crushed and dust in a space in a crusher where the material to be crushed and dust are present, Another object of the present invention is to provide an explosion-proof device for a crusher that can effectively prevent ignition and explosion by effectively diluting a combustible gas mass leaked into a space in the crusher.

The combustible gas detection method of the crusher according to the present invention is:
A method for detecting a flammable gas in a crusher that irradiates a space in a crusher with infrared light including an absorption wavelength and a reference wavelength in a combustible gas from a projector and receives the light with a light receiver.
When the infrared radiation intensity of the absorption wavelength is attenuated from the infrared radiation intensity of the reference wavelength, it is determined that there is a flammable gas mass in the space,
When the infrared radiation intensity of the absorption wavelength and the infrared radiation intensity of the reference wavelength are not attenuated and are substantially the same, it is determined that there is no inclusion in the space,
The infrared radiation intensity of the absorption wavelength and the infrared radiation intensity of the reference wavelength are attenuated to approximately the same level. When the attenuation is small, dust is present in the space portion. It is characterized by that.

Moreover, in the combustible gas detection method of the crusher,
A plurality of infrared optical axes are formed in a lattice shape on substantially the same plane,
The generation position of the combustible gas mass is specified from the crossing position of the optical axes where the combustible gas mass is detected.

Furthermore, the explosion-proof device of the crusher according to the present invention is:
A projector that is provided in the crusher and irradiates the space part from the inside of the casing with infrared rays including an absorption wavelength and a reference wavelength in the combustible gas,
A receiver that is provided on the casing and receives infrared rays of an absorption wavelength and an infrared wavelength of a reference wavelength,
A plurality of infrared optical axes arranged in a grid pattern on the substantially same plane between the projector and the receiver;
A plurality of explosion-proof gas nozzles for injecting a dilution gas for diluting the combustible gas mass provided in the casing;
Gas that detects the flammable gas mass based on the infrared radiation intensity of the absorption wavelength received by the light receiver and the infrared radiation intensity of the reference wavelength, and determines the position of the flammable gas mass from the crossing position of the infrared optical axis A detection determination unit;
When the gas detection judgment unit detects a flammable gas mass, select an explosion-proof gas nozzle corresponding to the position of the flammable gas mass, and dilute from the selected explosion-proof gas nozzle toward the flammable gas mass in the space. An explosion-proof control unit for injecting gas is provided.

Furthermore, in the explosion-proof device of the crusher configured as described above,
A substantially flat surface including the optical axis is arranged in at least one of the vicinity of the object to be crushed and the vicinity of the object to be crushed and the outlet of the rotator for crushing.

Moreover, in the explosion-proof device of the crusher having the above configuration,
The dilution gas is nitrogen gas,
The explosion-proof judgment unit stops the crusher when the gas detection judgment unit detects a combustible gas mass, and restarts when the combustible gas mass is diluted.

  According to the combustible gas detection method of the crusher according to the present invention, the absorption wavelength of the combustible gas and the radiation intensity of the reference wavelength are compared with each other, the absorption wavelength is attenuated from the reference wavelength, and the set radiation intensity difference It is judged that a flammable gas lump has been generated. Also, when the infrared absorption wavelength and the reference wavelength radiation intensity are substantially the same and are not attenuated, there are no inclusions in the space, and the absorption wavelength and the reference wavelength radiation intensity are attenuated approximately the same. When the attenuation is extremely large, it is determined that the object to be crushed exists. As a result, even if the object to be crushed, dust and combustible gas may coexist in the space of the crusher, it is possible to accurately determine the combustible gas and detect the generation of the combustible gas mass. . Here, the flammable gas mass refers to a flammable gas atmosphere space having a concentration that may cause ignition, combustion, or explosion due to a spark or the like.

  In addition, by arranging the optical axes of the infrared rays of the absorption wavelength and the reference wavelength in a lattice shape, it is possible to specify the generation position of the flammable gas mass from the crossing position based on the detected optical axis, thereby making the flammable It is possible to quickly and effectively cope with dilution, discharge, crushing stop, etc. for the gas mass.

  Furthermore, according to the explosion-proof device of the crusher, a flammable gas mass is generated at the intersection of the optical axes where the flammable gas is detected in the infrared optical axes arranged in a lattice pattern on substantially the same plane of the space. Can be determined. An explosion-proof gas nozzle capable of injecting the dilution gas toward the combustible gas mass is selected, and the dilution gas can be effectively injected from the explosion-proof gas nozzle toward the combustible gas mass. As a result, the combustible gas mass can be diluted quickly and effectively with a small amount of dilution gas, and ignition, combustion, and explosion due to the combustible gas leaked in the crusher can be prevented in advance.

  In addition, by placing the optical axes of the infrared rays in a crossed manner on one of the planes near the crushed material inlet side and the crushed material outlet side of the crushing rotating body where airflow tends to stay, combustible gas The generation position of the lump can be detected effectively.

  Further, by using nitrogen gas as the dilution gas, the absorption wavelength of the combustible gas is not affected by the nitrogen gas, and the diluted state of the combustible gas mass can be detected with high accuracy. Therefore, the gas detection determination unit can accurately detect that the difference in radiation intensity (ratio) between the absorption wavelength and the reference wavelength has decreased, thereby determining that the concentration of the combustible gas mass has decreased, The crusher can be restarted safely and quickly.

It is sectional drawing of the side view which shows the uniaxial scissor type crusher which has a combustible gas detection apparatus which concerns on this invention. It is AA sectional drawing shown in FIG. It is a block diagram which shows an explosion-proof device. (A)-(d) shows the relationship between the irradiation distance and the radiation intensity of the infrared ray of the absorption wavelength of the combustible gas and the infrared ray of the reference wavelength of the combustible gas, (a) is a state without inclusions and combustible gas, (B) shows a state where dust is present, (c) shows a state where combustible gas exists, and (d) shows a state where an object to be crushed exists. It is a graph which shows the change of the radiation intensity of the infrared of the absorption wavelength of combustible gas, and the infrared of the reference wavelength of combustible gas. It is sectional drawing of the side view which shows Example 2 of the biaxial horizontal crusher which has a combustible gas detection apparatus which concerns on this invention. It is BB sectional drawing which shows a biaxial horizontal crusher. It is a block diagram which shows the other Example of an infrared rays projector / receiver.

[Example 1]
Embodiment 1 of the present invention will be described below with reference to FIGS.
A large single-shaft vertical crusher 10 shown in FIGS. 1 and 2 is installed in, for example, a garbage collection facility or a waste recycling facility, and crushes large waste before treatment such as incineration. In this crusher 10, a drive motor 12 and a crusher main body 13 are erected in parallel on a base frame 11, and an output shaft of the drive motor 12 is wound around to drive the crusher main body 13 via a transmission mechanism 14. The shaft 15 is linked and connected.

  The crusher body 13 includes a casing 20 in which a drive shaft 15 is rotatably disposed in a vertical axial center part, and a knocker (rotating body for crushing) that is provided at the upper end of the drive shaft 15 and stirs an object to be crushed. 23, a rotor (crushing rotating body) 25 for crushing an object to be crushed by a plurality of grinders 24 provided at an intermediate portion of the drive shaft 15 and supported on an outer peripheral portion, and a swivel arm provided at a lower end portion of the drive shaft 15 Between the grinder 24 and the sweeper 26 which is provided with a scraping body 26 that feeds the crushed material to the discharge port 22 at the front end of the casing 20 and the grinder 24 on the inner peripheral surface of the casing 20. And a plurality of shell liners 27 for crushing the crushed material. For example, the casing 20 is formed to have a diameter of about 10 m, a crushing object input port 21 is opened above the knocker 23, and a crushed material discharge port 22 is opened on one side of the sweeper 26.

  In the above-described configuration, the material to be crushed that has been input into the casing 20 from the material to be crushed 21 is first fed to the outer peripheral portion while being stirred by the knocker 23, and then crushed between the grinder 24 and the shell liner 27. . The crushed material that has been crushed and dropped is sent out to the crushed material discharge port 22 by the sweeper 26.

An explosion-proof device 41 provided with a combustible gas detection device 31 according to the present invention will be described with reference to FIGS.
As shown in FIG. 3, the combustible gas detection device 31 is an infrared projector (projector) that irradiates the space 28 above the sweeper 26 in the casing 20 with infrared rays including at least the absorption wavelength of the combustible gas and the reference wavelength. 32, an infrared receiver (receiver) 33 that is disposed on the casing 20 facing each infrared projector 32 and receives infrared rays having an absorption wavelength and infrared rays having a reference wavelength, and an absorption wavelength received by the infrared receiver 33A. A gas detection determination unit 34 for detecting any one of the object to be crushed, dust, and combustible gas existing in the space 28 based on the difference in radiant intensity (ratio) of infrared rays of the reference wavelength and the difference in radiant intensity of each wavelength; Are provided.

  The plurality of pairs of infrared projectors 32 and infrared receivers 33 are disposed on the substantially same plane, for example, a horizontal plane, in the space 28 above the knocker 23, and the infrared optical axis IR is at a pitch of, for example, 0.5 to 2.0 m. They are arranged so as to intersect in a lattice pattern. Thereby, the position where the optical axes IR of the infrared ray projectors / receivers 32, 33 that have detected the combustible gas intersect can be specified as the generation position of the combustible gas mass. Here, the flammable gas mass refers to a flammable gas atmosphere space having a concentration that may cause ignition, combustion, or explosion due to a spark or the like.

  Further, in the crusher 10, an airflow is formed from the crushing material discharge port 22 toward the discharge port 22 using the crushing material discharge port 22 as a negative pressure so that dust does not rise and dissipate during crushing. In such an air flow, the portion where the air flow is most likely to stay is a space portion 28 above the sweeper 26, and the infrared light axis IR is arranged on the substantially the same horizontal plane in the space portion 28, thereby being effective. A flammable gas mass can be detected.

  The explosion-proof device 41 includes a combustible gas detection device 31, and a plurality of explosion-proof gas nozzles 42 that inject a dilution gas composed of an inert gas or water vapor into the casing 20 toward a predetermined portion of the space portion 28 at predetermined intervals. Is provided. The gas for dilution is an inert gas or water vapor, preferably nitrogen gas. When the gas detection determination unit 34 determines that a flammable gas mass has been generated in the space 28, the explosion detection is selected corresponding to the detected crossing position of the optical axis IR of the infrared emitter / receiver 32, 33. An explosion-proof control unit 43 that injects dilution gas from the gas nozzle 42 into the space 28 is provided. Based on the difference in radiation intensity between the absorption wavelength and the reference wavelength, the concentration of the combustible gas mass can be determined. Therefore, after determining that the radiation intensity difference (ratio) between the absorption wavelength and the reference wavelength has become sufficiently small after the injection of the dilution gas, the stopped crusher can be restarted.

Details will be described below.
The infrared rays irradiated on the space 28 from the infrared projector 32 include at least an infrared ray having an absorption wavelength of a combustible gas such as methane (CH4), propane (C3H8), and butane (C4H10) and an infrared ray having a reference wavelength. Table 1 shows typical examples of the absorption wavelength of combustible gases.

赤外線受光器３３は、吸収波長の赤外線A-IRのみを通過させる吸収波長用の波長選択（バンドパス）フィルタ３５Ａと、この波長選択フィルタ３５Ａを介して吸収波長の赤外線A-IRを受光する吸収波長受光部（受光素子）３３Ａと、リファレンス波長の赤外線R-IRのみを通過させるリファレンス波長用の波長選択（バンドパス）フィルタ３５Ｒと、このリファレンス波長用フィルタ３５Ｒを介してファレンス波長の赤外線R-IR受光するリファレンス波長受光部（受光素子）３３Ｒと、を具備している。ここで、吸収波長用の波長選択フィルタ３５Ａの選択波長は、３．１μｍ以上、３．５μｍ以下であり、リファレンス波長用の波長選択フィルタ３５Ｒの選択波長は、３．５を超え、４．１μｍ以下である。なお、上記の吸収波長およびリファレンス波長に限定されるものではなく、破砕物に含まれる可燃性ガスの成分に対応して、任意に選択することができる。

The infrared receiver 33 is a wavelength selection (bandpass) filter 35A for absorption wavelength that allows only the infrared A-IR of the absorption wavelength to pass, and absorption that receives the infrared A-IR of the absorption wavelength via the wavelength selection filter 35A. A wavelength light receiving unit (light receiving element) 33A, a reference wavelength selection filter (bandpass) filter 35R that passes only the reference wavelength infrared R-IR, and a reference wavelength infrared filter R through the reference wavelength filter 35R. And a reference wavelength light receiving part (light receiving element) 33R for receiving IR light. Here, the selection wavelength of the wavelength selection filter 35A for the absorption wavelength is 3.1 μm or more and 3.5 μm or less, and the selection wavelength of the wavelength selection filter 35R for the reference wavelength exceeds 3.5 and is 4.1 μm. It is as follows. In addition, it is not limited to said absorption wavelength and reference wavelength, According to the component of the combustible gas contained in a crushed material, it can select arbitrarily.

The signals detected by the absorption wavelength light receiving unit 35A and the reference wavelength light receiving unit 35R are amplified by the amplifiers 36A and 36R, respectively, and then output to the gas detection determination unit 34.
Next, the behavior of the absorption wavelength infrared A-IR and the reference wavelength infrared R-IR will be described with reference to FIGS.

  As shown in FIG. 4A, when there are no inclusions and flammable gas in the space 28, the infrared light A-IR of the absorption wavelength and the infrared light R-IR of the reference wavelength irradiated from the infrared projector 32 to the space 28. Are straightened while being attenuated slightly in the space 28 and are received by the infrared receiver 33 with substantially the same radiation intensity.

  As shown in FIG. 4B, when there is dust in the space 28, the infrared A-IR of the absorption wavelength and the infrared R-IR of the reference wavelength irradiated to the space 28 from the infrared projector 32 are contained in the dust. By being incident, the light travels straight while being attenuated at a constant rate, and is received by the infrared ray receiver 33 with a radiation intensity that is attenuated to a small extent at approximately the same level.

  As shown in FIG. 4 (c), when there is a flammable gas mass in the space 28, the infrared A-IR of the absorption wavelength among the infrared IR irradiated to the space 28 from the infrared projector 32 is caused by the flammable gas. The infrared R-IR of the reference wavelength is absorbed and greatly attenuated and travels straight in a slightly attenuated state with little absorption, and is received by the infrared receiver 33. If this radiation intensity difference (ratio) is detected exceeding a preset threshold value for a predetermined time, it is determined that a combustible gas mass exists on the optical axis IR of the space 28.

  As shown in FIG. 4 (d), when there is an object to be crushed in the space 28, the infrared A-IR of the absorption wavelength and the infrared R-IR of the reference wavelength irradiated to the space 28 from the infrared projector 32 are respectively The straight traveling is blocked by the object to be crushed, and is not received by the infrared receiver 33, and the radiation intensity becomes zero.

  FIG. 5 shows temporal changes in the radiation intensity of the infrared A-IR of the absorption wavelength and the infrared R-IR of the reference wavelength received by the infrared receiver 33 in, for example, a pair of infrared emitter / receivers 32 and 33. The radiation intensity of infrared A-IR and R-IR of both wavelengths changes with the passage of time, and the infrared A-IR and R-IR are absorbed by, for example, objects to be crushed and dust in the space 28. Scattered and attenuated to the same extent. Also, if there is a flammable gas mass in the space 28, the infrared A-IR of the absorption wavelength is greatly attenuated, but the infrared R-IR of the reference wavelength is hardly attenuated, resulting in a large difference in radiation intensity. When this radiation intensity difference (ratio) becomes large and exceeds a preset threshold value of radiation intensity difference and exceeds a threshold value for a certain period of time or a moving average value for a certain period of time exceeds a threshold value, the detection / determination unit 34 Then, it is determined that a combustible gas mass exists in the space portion 28.

  In the explosion-proof control unit 43, when the detection determination unit 34 determines that flammable gas is present, the explosion-proof control unit 43 determines the flammable gas mass from the intersection of the detected optical axes IR of the plurality of sets of infrared projectors / receivers 32 and 33. Specify the location. Then, an explosion-proof gas nozzle 42 capable of injecting dilution gas to the position where the combustible gas mass is generated and its peripheral part is selected, the electromagnetic on-off valve 44 of the selected explosion-proof gas nozzle 42 is opened, and a gas supply source (gas cylinder) The dilution gas is injected from 45 toward the combustible gas mass. At the same time, a stop signal is output to the motor controller 12 a of the drive motor 12 to stop the crusher 10. At the same time, the alarm buzzer 46 is activated and a warning display unit 47 displays a warning that a combustible gas mass has been detected.

  Here, an inert gas or water vapor can be used as the dilution gas, but nitrogen gas is preferred here. This is because the absorption wavelength of nitrogen gas is different from the infrared A-IR of the absorption wavelength of the flammable gas, and therefore does not affect the infrared R-IR of the reference wavelength. This is because it can be confirmed that the concentration of the combustible gas mass is sufficiently diluted by the gas. Thereby, the crusher 10 can be restarted safely after the gas detection judgment part 34 confirms the dilution of the combustible gas mass. Other inert gases and water vapor may adversely affect the measurement of infrared A-IR at the absorption wavelength of combustible gas and infrared R-IR at the reference wavelength. Argon gas Ar does not affect the infrared wavelength A-IR of the absorption wavelength and the infrared wavelength R-IR of the reference wavelength, but is not suitable for a dilution gas because it is expensive and increases the running cost.

  According to the combustible gas detection device 31 of the first embodiment, the absorption wavelength of the combustible gas and the infrared radiation A-IR, R-IR of the reference wavelength are detected and compared with each other, and the infrared light A- of the absorption wavelength is compared. When the IR is attenuated from the infrared R-IR of the reference wavelength and the difference (ratio) between the radiant intensities increases, it is determined that a flammable gas mass is generated in the space 28. Further, it is determined that there is no inclusion in the space portion 28 when the radiation intensity (ratio) of the infrared rays A-IR and R-IR of the absorption wavelength and the reference wavelength is substantially the same and is not attenuated, and further, the infrared rays of the absorption wavelength and the reference wavelength When the radiant intensity of A-IR and R-IR is attenuated substantially the same and the attenuation is small, it is determined that dust is present in the space portion 28, and when the attenuation is extremely large, it is determined that the object to be crushed exists. Thereby, even if a to-be-crushed object, dust, and combustible gas may coexist in the space part 28 of a crusher, a combustible gas lump can be discriminate | determined and detected accurately.

  Further, by arranging the infrared optical axis IR in a grid pattern, the generation position of the combustible gas mass can be specified from the crossing position based on the detected optical axis IR of the infrared projector / receiver 32, 33. . Thereby, dilution with respect to a combustible gas lump can be performed rapidly and effectively.

  Further, according to the explosion-proof device 41, in the infrared optical axis IR arranged in a lattice pattern on substantially the same plane, it is selected toward the combustible gas mass existing at the intersection of the optical axis IR where the combustible gas is detected. The dilution gas can be injected from the explosion-proof gas nozzle 42. Therefore, the flammable gas lump can be effectively and quickly diluted with a small amount of dilution gas, and ignition, combustion, and explosion of the flammable gas can be prevented in advance.

  Furthermore, by arranging the infrared optical axes IR in a crossing manner on a substantially flat surface in the vicinity of the object to be crushed inlet of the rotor 25 and knocker 23 which are rotators for crushing in which airflow tends to stay, combustible gas The lump can be detected with high accuracy, and the combustible gas can be effectively diluted with a small amount of dilution gas.

In the first embodiment, the crusher body 13 and the drive motor 12 are arranged in parallel on the base frame 11, but the drive motor 12 is attached to the upper end of the drive shaft 15 so that the crusher body 13 and the drive motor 12 are integrated. The structure may be as follows.
[Example 2]
A biaxial horizontal crusher having an explosion-proof device equipped with a combustible gas detection device according to the present invention will be described with reference to FIGS. 6 and 7. Note that the same members as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The crusher 50 is smaller than the single-shaft vertical crusher of the first embodiment, and a plurality of crushing blades 52R and 52L are attached to drive shafts 51R and 51L, which are parallel to each other, in the casing 54, respectively. It has been. And drive shaft 51R, 51L is rotationally driven by the drive motor which is not shown in the relative direction which crushing blade 52R, 52L meshes in the center upper part. The casing 54 is provided with fixed blades 53 that mesh with the crushing blades 52R and 52L, respectively.

  In this crusher 50, a crushing object input port 55 is opened above the casing 54, and a crushing material discharge port 56 is opened below the casing 54. And the airflow is formed toward the discharge port 56 from the input port 55 of the to-be-crushed object by making the discharge port 56 into a negative pressure. The infrared projector 32 and the infrared receiver 33 are installed in the casing 54 so that the infrared optical axis IR intersects the substantially horizontal plane in the space portion 28 below the crushing blades 52R and 52L where the airflow tends to stay. ing. Of course, as shown by the phantom lines, the infrared projectors / receivers 32, 33 are arranged in the space above the crushing blades 52R, 52L so that the infrared optical axes IR intersect each other on a substantially horizontal plane. Also good. In addition, infrared projectors / receivers 32 and 33 can be disposed in the space above and below the crushing blades 52R and 52L, respectively.

The other combustible gas detection device and the explosion-proof device are configured in the same manner, and the same effects as those of the first embodiment can be achieved.
[Other Examples of Combustible Gas Detection Device]
In the infrared receivers 33 of the first and second embodiments, the wavelength selection filters 35A and 35R are used. As shown in FIG. 8, an LED or semiconductor laser 62A that emits infrared A-IR having an absorption wavelength of a combustible gas is used. The infrared projector 62 may include an LED or a semiconductor laser 62R that emits infrared R-IR having a reference wavelength of a combustible gas. In this case, the infrared light receiver 63 includes an absorption wavelength light receiving element 63A that receives infrared light A-IR having an absorption wavelength and a reference wavelength light receiving element 63R that receives infrared light R-IR having a reference wavelength. Since LEDs or semiconductor lasers generate infrared light with a narrow wavelength, when supporting a plurality of types of flammable gases, infrared A-IR with a plurality of absorption wavelengths and infrared light with a plurality of reference wavelengths are necessary. The infrared projector / receiver may be configured to emit and receive R-IR.

IR Infrared A-IR Absorbing Wavelength Infrared R-IR Reference Wavelength Infrared 10 Crusher 15 Drive Shaft 20 Casing 21 Fracture Input Port 22 Fracture Discharge Port 23 Knocker (Rotating Body for Crushing)
24 Grinder (Rotating body for crushing)
25 Rotor (Rotating body for crushing)
26 Sweeper (Rotating body for crushing)
27 Shell liner 28 Space 31 Flammable gas detector 32 Infrared projector 33A, 33R Infrared receiver 34 Gas detection determination unit 35A, 35R Wavelength selection filter 41 Explosion-proof device 42 Explosion-proof gas nozzle 43 Explosion-proof control unit

Claims (5)

A method for detecting a combustible gas in a crusher that irradiates a space inside a crusher with infrared light including an absorption wavelength and a reference wavelength in a combustible gas from a projector and receives the light with a light receiver.
When the infrared radiation intensity at the absorption wavelength is attenuated from the infrared radiation intensity at the reference wavelength, it is determined that there is a flammable gas mass in the space,
When the infrared radiation intensity of the absorption wavelength and the infrared radiation intensity of the reference wavelength are not attenuated and are substantially the same, it is determined that there is no inclusion in the space,
The infrared radiation intensity of the absorption wavelength and the infrared radiation intensity of the reference wavelength are attenuated to approximately the same level. When the attenuation is small, dust is present in the space portion. The combustible gas detection method of the crusher characterized by the above-mentioned. A plurality of infrared optical axes are formed in a lattice shape on substantially the same plane,
The method for detecting a combustible gas in a crusher according to claim 1, wherein the position where the combustible gas mass is present is specified from the crossing position of the optical axes where the combustible gas mass is detected. A projector that is provided in the crusher and irradiates the space part from the inside of the casing with infrared rays including an absorption wavelength and a reference wavelength in the combustible gas,
A light receiver that is provided in the casing and receives each of infrared rays having an absorption wavelength and infrared rays having a reference wavelength;
A plurality of infrared optical axes arranged in a grid pattern on the substantially same plane between the projector and the receiver;
A plurality of explosion-proof gas nozzles for injecting a dilution gas for diluting the combustible gas mass provided in the casing;
Gas that detects the flammable gas mass based on the infrared radiation intensity of the absorption wavelength received by the light receiver and the infrared radiation intensity of the reference wavelength, and determines the position of the flammable gas mass from the crossing position of the infrared optical axis A detection determination unit;
When the gas detection judgment unit detects the flammable gas mass, the explosion proof gas nozzle corresponding to the position of the flammable gas mass is selected, and the dilution gas is supplied from the selected explosion proof gas nozzle toward the flammable gas mass in the space. An explosion-proof control unit for spraying, and an explosion-proof device for a crusher. 4. The explosion-proof device for a crusher according to claim 3, wherein a substantially flat surface including the optical axis is arranged in at least one of the vicinity of the crushing material inlet side and the crushing material outlet side of the crushing rotating body. The dilution gas is nitrogen gas,
5. The crusher according to claim 3 or 4, wherein the explosion-proof judgment unit stops the crusher when the gas detection judgment unit detects the combustible gas mass, and restarts when the combustible gas mass is diluted. Explosion-proof device.

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