JP5313794B2 - High level detector and industrial furnace - Google Patents

Description

  The present invention relates to a layer high level detection device and an industrial furnace, and more particularly to a layer high level detection device for detecting a layer height level in an industrial furnace using a microwave and an industrial furnace including the layer high level detection device.

  As one of the furnaces (industrial furnaces) used for industrial purposes, there is a waste melting furnace for processing waste by gasification and melting in order to treat waste such as general waste and industrial waste. . The waste melting furnace is provided with a layer height level detection device for grasping the amount of waste in the furnace, and operates according to the layer height state detected by this device.

  A level detector using a microwave is a non-contact type level detector widely adopted regardless of the technical field. However, if it is installed in a waste melting furnace as it is, damage or the like is likely to occur due to the heat of the high-temperature gas rising in the furnace, so a protective measure for suppressing the influence of heat is necessary. In addition, it is necessary to take measures to suppress the influence on the detection accuracy caused by adhesion of dust, oil, moisture, etc. (hereinafter referred to as “dust etc.”) accompanying the gas.

  As shown in FIGS. 3 and 4, Patent Literature 1 discloses a layer high level detection device 2 provided on an upper portion of a shaft of a waste melting furnace 1. This layer high level detection device 2 disclosed in Patent Document 1 is provided with a microwave level detector 22 on an upper part of a cylindrical body 21 fixedly disposed in the waste melting furnace 1, and an antenna 23 for transmitting and receiving microwaves. In the cylindrical body 21. As a protective measure for suppressing the influence of high-temperature gas, dust, etc., a porous ceramic plate 24 having air permeability is provided at the lower portion of the cylindrical body 21 and the inside of the cylindrical body 21 partitioned by the porous ceramic plate 24 is provided. The purge gas is blown so that the region is higher than the furnace pressure.

  However, even if the cylindrical body 21 is purged, it is difficult to completely prevent dust and the like from adhering to the furnace inner surface of the porous ceramic plate 24. If dust or the like adheres to the surface of the porous ceramic plate 24, microwaves may be reflected by the dust or the like, and stable detection may not be performed. Therefore, it is necessary to replace the porous ceramic plate 24 or to perform a cleaning operation to remove attached dust and the like.

Japanese Patent No. 3817086

  That is, the present invention has been made to solve the above-mentioned problem given as an example, and its purpose is to suppress the influence of heat in the industrial furnace and to affect the detection accuracy due to the adhesion of dust and the like. An object of the present invention is to provide a layer high level detection device and an industrial furnace capable of suppressing the above.

The layer high level detection device according to the present invention is a layer high level detection device that detects a layer height level in an industrial furnace using a microwave, a transmitter for transmitting microwaves into the furnace, and a reflected microwave. comprising a receiving unit for a microwave level detecting meter having a ceramic fiber filter which separates the transmitting unit and the receiving unit from the furnace space, and a gas supply device for supplying a pulse gas to said ceramic fiber filter The ceramic fiber filter has a deformability that is deformed by the pressure of pulp gas supplied from the gas supply device .

  As a preferred example, the layer high level detection device is connected to a first cylindrical body in which an antenna for transmitting and / or receiving microwaves is housed, and a lower part of the first cylindrical body, and And a second cylindrical body having an inlet for purge gas, and the ceramic fiber filter can be disposed so as to cover a lower surface opening of the second cylindrical body. .

  As another preferable example, an antenna for transmitting and / or receiving microwaves is formed in, for example, a cone shape, a bowl shape, a cylinder or a rectangular shape, and all or a part of the internal space of the antenna is separated from the furnace space. Ceramic fiber filters can be arranged as described. In this case, for example, it can arrange | position so that the front-end | tip opening part of the antenna which transmits and / or receives a microwave may be covered. And it is preferable to supply both the pulse gas from the said gas supply apparatus and purge gas to the internal space of the antenna separated from the space in a furnace.

  Further, the gas supply device also serves as a device for supplying purge gas to the internal space of the antenna separated from the furnace space, and continuously supplies the purge gas at a pressure higher than at least the furnace pressure, It is preferable to further include a pulse gas valve that generates a pulse gas by changing the pressure and / or flow rate of the gas.

The ceramic fiber filter preferably has a specific resistance of 10 ³ (ohm-cm) or more, particularly 10 ⁶ (ohm-cm) or more, and preferably has a heat resistant temperature of 300 ° C. or more. As such a ceramic fiber filter, for example, a cloth-like filter formed of ceramic continuous fibers made of silicon, titanium, zirconium, carbon, or oxygen can be cited as an example.

  The industrial furnace of the present invention includes the above-described layer high level detection device.

  According to the present invention, the ceramic fiber filter having heat resistance is disposed so as to separate the transmitter and receiver of the microwave level detector from the space in the furnace, and a pulse gas is supplied to the ceramic fiber filter. As a result, the dust attached to the surface can be automatically removed by the deformability of the ceramic fiber filter due to the internal pressure difference between the inner and outer surfaces and the pulse pressure. As a result, it is possible to suppress the influence on the detection accuracy due to the adhesion of dust or the like.

1 shows a layer high level detection device according to a first embodiment of the present invention. 6 shows a layer high level sensing device according to a second embodiment of the present invention. 1 shows a conventional layer high level detector. An example in which the layer high level detection device is arranged in the upper part of the waste melting furnace is shown.

  Hereinafter, a layer height level detection device according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. However, the technical scope of the present invention is not construed as being limited by the embodiments described below.

(First embodiment)
FIG. 1 shows an example in which a layer high level detection device 3 according to a preferred embodiment of the present invention is arranged at the upper part of a waste melting furnace 1 as shown in FIG. As shown in FIG. 1, the layer height level detection device 3 is a first antenna housing body that is detachably connected to a nozzle 10 formed in an upper portion of a furnace body via an opening / closing device such as a gate valve 4. The cylindrical body 31A and the second cylindrical body 31B having an inlet for introducing purge gas and pulse gas are provided. The microwave level detector (main body) 32 is detachably provided on the upper side of the first cylindrical body 31 </ b> A by a flange 33. On the other hand, the antenna 34 of the microwave level detector 32 is accommodated in the first cylindrical body 31A. In the configuration of the present embodiment, the antenna 34 that transmits and receives microwaves corresponds to a microwave transmitter and receiver.

  Note that the gate valve 4 is opened and closed by a handle 41 when performing maintenance work of a microwave level detector, for example, and the valve is normally opened. In FIG. 1, the flange and the bolt / nut are used as a structure that allows the microwave level detector and the gate valve to be attached and detached. However, the structure is not limited to this.

  The microwave level detector (main body) 32 generates a microwave and transmits it to the antenna 34. The microwave reflected from the antenna 34 is reflected from the upper surface (that is, the layer high level) of the waste group in the furnace. A receiver for receiving, and an arithmetic unit (for example, an arithmetic circuit) that obtains a layer height level by calculation based on, for example, attenuation from the transmitted and received microwaves. However, for example, the calculator may be omitted from the microwave level detector (main body) 32 by obtaining a layer height level by a control unit that controls the overall operation of the waste melting furnace 1.

  For example, the antenna 34 is formed in a cone shape whose diameter increases toward the tip. At this time, as shown in FIG. 1, it is preferable to set the outer diameter of the tip of the antenna 34 to be substantially the same as the inner diameter of the first cylindrical body 31A. Furthermore, a seal member for eliminating a gap between the tip of the antenna 34 and the first cylindrical body 31A may be provided.

  On the lower surface side of the second tubular body 31B, a ceramic fiber filter 35 that partitions the internal space of the tubular body 31B and the furnace space is provided. That is, the antenna 34 is separated from the furnace space by the ceramic fiber filter 35. As an example, the ceramic fiber filter 35 can be fixed by being sandwiched between the flange of the second cylindrical body 31 </ b> B and the flange of the gate valve 4. The ceramic fiber filter 35 is preferably in the form of a cloth formed of ceramic continuous fibers made of, for example, silicon, titanium, zirconium, carbon, or oxygen.

In the case of the ceramic fiber filter 35, it is desirable that the specific resistance is 10 ³ (ohm-cm) or more, especially 10 ⁶ (ohm-cm) or more. This is because when the specific resistance is lower than 10 ³ (ohm-cm), the microwave passing through the fiber filter 35 is reflected, and the detection accuracy may be lowered. If the specific resistance is 10 ³ (ohm-cm) or more, this reflection can be prevented, but if the specific resistance is 10 ⁶ (ohm-cm) or more, the reflection can be minimized. Furthermore, in order to suppress the influence of the high temperature gas rising in the furnace, it is preferable to use one having a heat resistance of 300 ° C. or higher.

  Furthermore, the layer high level detection device 3 according to the present embodiment has a gas supply device 5 for supplying purge gas and pulse gas to the internal space of the second cylindrical body 31B separated from the furnace space by the ceramic fiber filter 35, respectively. It has. The purge gas supply system performs a continuous purge through a gas supply pipe 51 connected to an inert gas supply source (not shown) such as nitrogen gas. On the other hand, in the pulse gas supply system, for example, a pulse gas valve 53 and a blaster tank 54 for generating pulse gas are connected to a gas supply pipe 52 connected to an inert gas supply source (not shown) such as nitrogen gas. It is a configuration.

  The purge gas supply system continuously supplies the inert gas so that the internal space of the antenna 34 is purged at a pressure higher than the pressure in the furnace. On the other hand, the operation of the pulse gas supply system is sometimes controlled so as to intermittently generate pulse gas. For example, by opening and closing the valve body of the pulse gas valve 53, the pressure and / or flow rate of the gas can be varied to generate the pulse gas. In this case, the type and shape of the valve itself are not limited, and a general valve that can automatically control the opening / closing operation can be used. Further, the opening / closing operation is automatically or manually controlled by a control panel arranged on the site, for example. However, the present invention is not limited to this, and the control can be performed by a control unit that controls the entire operation of the waste melting furnace 1. The control unit can be configured by, for example, a computer having a CPU, and information such as timing for generating pulse gas can be stored in a memory or the like.

  As the timing for generating the pulse gas, for example, it may be periodically generated at a predetermined cycle (for example, every hour), or a detection signal disturbance (noise, etc.) is a predetermined threshold. You may make it generate | occur | produce when it becomes above. Furthermore, you may perform control which combined both of these.

  As described above, the gas supply device 5 is preferably constituted by two systems in which the pulse gas supply system and the purge gas supply system are separately provided. However, the present invention is not limited to this, and it may be configured by one system.

  In the layer high level detection device 3 of the present embodiment having the above-described configuration, microwaves are transmitted and received to detect the waste layer high level, and at least the internal space of the antenna 34 has a pressure higher than the furnace pressure. An inert gas is supplied and purged. The purged gas flows out into the furnace substantially uniformly in a plane through the gap between the fibers of the ceramic fiber filter 35. Therefore, the gas supply device 5 continuously supplies the purge gas so that the internal space of the antenna 34 is maintained at a constant pressure to compensate for this outflow.

  By supplying the purge gas, it is possible to prevent dust and the like from adhering to the surface of the ceramic fiber filter 35. However, as described in the background art section, it is difficult to completely prevent the adhesion of dust and the like, and dust, tar, and the like may adhere depending on the operating conditions and operating time of the furnace. Therefore, in this embodiment, pulse gas is intermittently generated and supplied to the ceramic fiber filter 35. Unlike the conventional hard ceramic plate (24), the ceramic fiber filter 35 has a deformability due to an internal pressure difference between the inner and outer surfaces and a pulse pressure, so it is possible to remove dust and the like adhering to the surface. It becomes. In addition, the use of the pulse method prevents the occurrence of microwave noise.

  As described above, according to the layer high level detection device 3 according to the present embodiment, the ceramic fiber filter 35 having heat resistance is adopted as the member that separates the antenna 34 that transmits and receives microwaves from the space in the furnace, and the ceramic With the gas supply device 5 for supplying the pulse gas to the fiber filter 35, it is possible to automatically remove dust and the like adhering to the surface due to the internal pressure difference between the inner and outer surfaces and the deformability due to the pulse pressure. Become. As a result, the influence of heat can be suppressed, and the influence on the detection accuracy due to adhesion of dust or the like can also be suppressed. Accordingly, it is possible to perform stable layer high level detection over a long period of time.

  As described above, since the layer high level detection device 3 according to the present embodiment can automatically remove dust and the like, it is possible to greatly extend the period of performing maintenance work such as replacement and cleaning of the fiber filter 35. Therefore, the burden on the worker can be reduced by that amount.

  Furthermore, according to the present embodiment, the second cylindrical body 31B having the introduction port to which the continuous purge gas and the pulse gas are supplied is provided, thereby increasing the blaster effect by increasing the diameter of the introduction port. It is possible to increase the effect of dust removal. In addition, in this embodiment, although it was set as the structure provided with 31 A of 1st cylindrical bodies and the 2nd cylindrical body, it is not limited to this, You may comprise by one cylindrical body.

(Second Embodiment)
As shown in FIG. 2, the present embodiment is a modification of the first embodiment in which the arrangement position of the ceramic fiber filter 35 is the tip of the antenna 34. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The ceramic fiber filter 35 of the present embodiment is provided so as to cover the tip opening of the antenna 34. Thereby, the internal space of the antenna 34 and the space in the furnace are separated by the ceramic fiber filter 35. As an example, the ceramic fiber filter 35 can be fixed by being sandwiched by a flange (not shown) provided at the tip of the antenna 34.

  The gas supply device 5 supplies a purge gas and a pulse gas to the internal space of the antenna 34 separated from the space in the furnace by the ceramic fiber filter 35. Therefore, the second cylindrical body 31B is omitted, and a gas supply path 55 that communicates with the internal space of the antenna is formed inside the flange 33 that is positioned above the first cylindrical body 31A.

  Also in the second embodiment described above, the ceramic fiber filter 35 has the deformability due to the internal pressure difference between the inner and outer surfaces and the pulse pressure, so it is possible to remove dust and the like adhering to the surface. The same effect as the form can be obtained.

  Furthermore, the use of the ceramic fiber filter 35 makes it possible to easily attach the fiber filter 35 to the antenna 34, thereby allowing the fiber filter to be attached and detached integrally with the microwave level detector. There are advantages. However, the installation location of the ceramic fiber filter 35 is not limited to the antenna 34 alone, and may be installed in both FIG. 1 and FIG. 2, for example.

  Furthermore, by arranging the ceramic fiber filter 35 on the front surface of the antenna 34, the range to be purged (that is, the volume) can be reduced, and further, the purge of the fiber filter 35 by the purge from the inside of the antenna 34. It is possible to purge the surface uniformly.

  In addition, although the cone-shaped antenna 34 was shown as an example in the above-mentioned embodiment, it is not limited to this shape, For example, shapes, such as bowl shape, cylindrical shape, rectangular shape, may be sufficient. In this case, the shape of the cylindrical body (that is, the antenna housing body) that accommodates the antenna 34 can also be a shape that matches the shape of the antenna.

  Furthermore, the installation position of the layer height level detection device 3 is not limited to the upper part of the furnace as shown in FIG. 4, but may be installed on the side surface of the furnace. In this case, for example, two antennas for transmitting and receiving microwaves may be arranged at positions facing each other on the side surface of the furnace. Furthermore, it is not always necessary to obtain the layer height level by calculation or the like. For example, it is only necessary to detect whether or not the waste has accumulated to a predetermined height.

  Furthermore, the above-mentioned layer high level detection device is not limited to the waste melting furnace, but is installed in various known industrial furnaces to detect the layer high level of the input in the furnace. It goes without saying that it is possible.

  As described above, in the layer high level detection device that detects the layer height level in the industrial furnace using the microwave, the transmitter that transmits the microwave into the furnace, and the receiver that receives the reflected microwave. By including a microwave level detector, a ceramic fiber filter that separates the transmitter and the receiver from the furnace space, and a gas supply device that supplies a pulse gas to the ceramic fiber filter, While suppressing the influence of the heat in a furnace, the influence on the detection precision by dust etc. adhering can be suppressed.

  Although the present invention has been described in detail with reference to specific embodiments, various substitutions, modifications, changes, etc. in form and detail are defined in the claims. It will be apparent to those skilled in the art that this can be done without departing from the spirit and scope. Therefore, the scope of the present invention should not be limited to the above-described embodiments and the accompanying drawings, but should be determined based on the description of the claims and equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Waste melting furnace 3 Layer high level detection apparatus 31A 1st cylindrical body (antenna container)
31B Second cylindrical body 32 Microwave level detector 34 Antenna 35 Ceramic fiber filter 5 Gas supply device 53 Pulse gas valve 54 Blaster tank

Claims (9)

In the layer high level detection device that detects the layer high level in an industrial furnace using microwaves,
A microwave level detector having a transmitter for transmitting microwaves in the furnace and a receiver for receiving reflected microwaves;
A ceramic fiber filter which separates the transmitting unit and the receiving unit from the furnace space,
A gas supply device for supplying a pulse gas to the ceramic fiber filter ,
The ceramic fiber filter has a deformability that is deformed by the pressure of pulp gas supplied from the gas supply device. 2. The layer high level detection device according to claim 1, wherein the ceramic fiber filter is installed at a position separating an internal space of an antenna that transmits and / or receives the microwave from a space in a furnace. A first tubular body in which the antenna is accommodated;
A second cylindrical body connected to a lower portion of the first cylindrical body, and having a pulse gas inlet and a purge gas inlet;
3. The layer high level detection device according to claim 2, wherein the ceramic fiber filter is disposed so as to cover a lower surface opening of the second cylindrical body.   3. The layer high level detection device according to claim 2, wherein the ceramic fiber filter is arranged so as to cover a front end opening of an antenna that transmits and / or receives the microwave. 4.   5. The gas supply device according to claim 4, further comprising: a pulse gas supply path for supplying the pulse gas and a purge gas supply path for supplying a purge gas in an antenna internal space separated from a furnace space by the ceramic fiber filter. The layer high level detection device according to 1.   The layer high level according to any one of claims 1 to 5, wherein the gas supply device further includes a pulse gas valve that generates a pulse gas by intermittently changing the pressure and / or flow rate of the gas. Detection device. The layer height level according to any one of claims 1 to 6, wherein the ceramic fiber filter has a specific resistance of 10 ³ (ohm-cm) or more and a heat resistant temperature of 300 ° C or more. Detection device.   8. The layer high level detection device according to claim 7, wherein the ceramic fiber filter is a cloth-like filter formed of continuous ceramic fibers made of silicon, titanium, zirconium, carbon, or oxygen. An industrial furnace comprising the layer high level detection device according to any one of claims 1 to 8.

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