JP5395000B2 - Method and apparatus for measuring remaining thickness of molten cast refractory - Google Patents

Description

  The present invention relates to a method and a measurement apparatus for measuring the remaining thickness of a molten cast refractory used in a glass melting furnace, and in particular, the remaining thickness of a molten cast refractory used on the side wall of a glass melting furnace in operation. The present invention relates to a measurement method and a measurement apparatus that can measure without disturbing operations.

  The glass melting kiln is constructed using a molten cast refractory on the side wall, which is used at a very high temperature for melting glass and has a property that does not adversely affect the molten glass.

  In this glass melting furnace, as the operation continues, the molten cast refractory that is in contact with the molten glass is gradually eroded and its thickness decreases. And when the thickness becomes thinner than the predetermined range, the kiln is repaired to extend the life, or the kiln is stopped as the life of the kiln.

  If this operation is not performed properly and the operation is continued beyond the limit, a serious accident may occur in which the molten glass refractory is perforated and the molten glass body leaks out of the kiln. On the other hand, looking at safety, if the kiln is stopped even though there is still a sufficient remaining thickness, and the durability is sufficient, a large loss is caused in terms of cost.

  For the above reasons, it is very important to grasp the remaining thickness of the refractory while continuing the operation, and there is a strong demand from the glass kiln user.

  In order to measure the remaining thickness of the refractory, a conventionally used method is the length from the joint of the molten cast refractory at the glass contact portion to the time when the metal ruler is inserted and contacted with the molten glass. There is a method of measuring the remaining thickness. In this method, in addition to knowing only the remaining thickness of the joint, there is a case where the molten cast refractory is weak and the glass is oozed into the joint when the joint is open, so there is a case where the accurate remaining thickness cannot be measured. There are many.

  In addition, when the remaining thickness becomes thin, there is a method of estimating the remaining thickness from the temperature change outside the kiln by using the fact that the temperature outside the kiln of the refractory increases. However, in practice, the outside surface of the kiln is generally forcedly cooled with air, and changes in the outside temperature of the kiln include various changes such as fluctuations in air cooling conditions, outside air temperature fluctuations due to seasonal fluctuations, and fluctuations in the kiln temperature. Factors are related. Therefore, in order to directly relate the change in the temperature outside the kiln to the erosion status of the refractory, these factors must be analyzed accurately, and it is extremely difficult to measure the thickness at a level that can withstand practical use.

  It is also conceivable to measure the remaining thickness by an X-ray flaw detection method or an ultrasonic flaw detection method. However, X-ray flaw detection requires a high-power X-ray device to measure the thickness of large ceramics containing heavy elements such as zirconia, such as substances with low X-ray transmittance. In order to transmit ultrasonic waves well to the inside of the molten cast refractory material, a good ultrasonic transmission medium such as water or grease is required at the interface between the molten cast refractory and the sensor, and sometimes the molten cast refractory exceeding 500 ° C Ultrasonic measurement from the surface had a problem in feasibility.

  Under such circumstances, a method using an electromagnetic wave flaw detection sensor has been studied, and in order to protect the sensor portion from high heat, a furnace furnace heat-resistant brick thickness measuring apparatus and method are proposed by covering with a heat insulating material such as ceramic fiber. (See Patent Document 1). In the case of electromagnetic waves, unlike ultrasonic waves, no transmission medium such as water or grease is required, and electromagnetic waves can be transmitted into a refractory and the delay time for returning the reflected wave from the back can be measured. Therefore, if the relative permittivity of the molten cast refractory is known, the transmission speed of the electromagnetic wave in the refractory is determined, so that it can be easily converted into a thickness.

  In addition, a measurement method using electromagnetic waves has been proposed as a method for measuring the quality of internal defects in molten cast refractories at room temperature by utilizing such characteristics of electromagnetic waves (see Patent Document 2).

JP-A-4-81679 JP-A-5-322800

  However, during the operation of the glass melting kiln, the temperature inside the kiln is set to a high temperature of 1500 ° C. or higher, and the temperature outside the kiln of the refractory is generally several hundred ° C. or higher. As described above, when the refractory becomes high temperature, the relative dielectric constant largely changes from the room temperature value. Further, when the temperature of the refractory becomes high, the attenuation of electromagnetic waves inside the refractory becomes very large, and there is a problem that it is much more difficult to obtain a reflected wave on the inner surface of the kiln than at room temperature.

  Accordingly, the present invention has been made to solve the above-described problems, and is a fusion cast refractory that can more accurately measure the thickness of the side wall made of a fusion cast refractory while continuing the operation of the glass melting furnace. An object is to provide a remaining thickness measuring method and a measuring apparatus.

The method for measuring the remaining thickness of the molten cast refractory according to the present invention is a method for measuring the remaining thickness of the molten cast refractory used on the side wall of the glass melting furnace, and having the same composition as the molten cast refractory to be measured. While heating one side of the reference molten cast refractory to a temperature substantially equal to the temperature in the glass melting furnace, the other side of the reference molten cast refractory has a heat resistance temperature of 250 ° C. or higher. A heat insulating plate having a dielectric constant of 2 to 20 and a temperature diffusivity of 2 × 10 ⁻⁶ m ² / sec or less is brought into contact, and a pulsed electromagnetic wave having a center frequency of 0.5 to 3 GHz is contacted through the heat insulating plate. Transmitting to the molten cast refractory for the control, and obtaining reflected wave data of the pulsed electromagnetic wave from the heated side surface of the molten cast refractory for control of the reference electromagnetic wave. A step of obtaining an apparent relative dielectric constant; Contact with the outer peripheral surface of the measurement to be fused cast refractories of the melting furnace, heat resistant temperature 250 ° C. or higher, relative dielectric constant of 2 to 20, the thermal diffusivity is ² × 10 -6 ^m 2 / ^sec or less of the heat insulating plate Transmitting the electromagnetic wave having the same frequency as the pulsed electromagnetic wave transmitted to the reference molten cast refractory through the heat insulating plate toward the molten cast refractory to be measured, and the melting of the pulsed electromagnetic wave. The process of obtaining the reflected wave data from the inner peripheral surface of the cast refractory, the propagation time of the pulsed electromagnetic wave obtained from the reflected wave data of the pulsed electromagnetic wave in the molten cast refractory, and the control melting And a step of calculating a remaining thickness of the molten cast refractory from an apparent relative dielectric constant determined for the cast refractory.
In this specification, the relative dielectric constant is a value measured by a cavity resonance method at room temperature (25 ° C.) and a frequency of 1 GHz unless otherwise specified.

The molten cast refractory residual thickness measuring apparatus of the present invention has a heat resistance temperature of 250, which is brought into contact with the outer peripheral surface of the molten cast refractory when measuring the residual thickness of the molten cast refractory used on the side wall of the glass melting furnace. A heat insulating plate with a relative dielectric constant of 2 to 20 and a thermal diffusivity of 2 × 10 ⁻⁶ m ² / sec or less, and a pulsed electromagnetic wave on the outer peripheral surface of the molten cast refractory through the heat insulating plate. An electromagnetic wave probe comprising: a transmitter for transmitting from a transmitting antenna toward the receiver; and a receiver for receiving reflected waves from the molten cast refractory of the pulsed electromagnetic wave with a receiving antenna to obtain reflected wave data. It is characterized by being configured.

  According to the remaining thickness measuring method and the remaining thickness measuring apparatus of the molten cast refractory according to the present invention, it is possible to measure the more accurate remaining thickness on the side wall of the glass melting furnace by a simple operation than in the conventional measurement. In particular, it is possible to perform stable measurements even in high-temperature molten cast refractories with high zirconia content, and accurately determine whether or not to continue operation of the glass melting furnace with a practical level of accuracy. it can.

  As a result, the remaining thickness still remains at the end of the glass melting kiln, and the melting kiln can be stopped even though the durability is sufficient. Occurrence of a situation where the molten glass substrate flows out can be prevented.

It is the figure which showed schematic structure of the remaining thickness measuring apparatus of the fusion cast refractory of this invention. It is the sectional side view which showed the structure of the glass melting kiln. It is a figure explaining the partial enlarged view of the structure of the molten cast refractory which is a to-be-measured object, and the remaining thickness measuring method. It is a flowchart of the remaining thickness measuring method of the fusion cast refractory which concerns on 1st Embodiment. It is a figure explaining the contrast test of the remaining thickness measuring method of the fusion cast refractory in this invention. It is a figure explaining the erosion situation of a fusion cast refractory over time. It is a flowchart of the remaining thickness measuring method of the fusion cast refractory which concerns on 2nd Embodiment. FIG. 3 is a diagram showing the measurement results of a control test at a high temperature in Example 1. FIG. 3 is a diagram showing the measurement results of a control test at room temperature in Example 1. It is the figure which showed the measurement result of the real kiln of Example 1. FIG. FIG. 6 is a diagram showing measurement results of a control test of Example 2. It is the figure which showed the relationship between a scanning direction (horizontal direction) and the remaining thickness of a fusion | melting cast refractory about the measurement result of the real kiln of Example 2. FIG.

  Hereinafter, a method and an apparatus for measuring a remaining thickness of a molten cast refractory according to the present invention will be described in detail with reference to the drawings.

[First Embodiment]
As shown in FIG. 1, an apparatus 1 for measuring a remaining thickness of a molten cast refractory (hereinafter also simply referred to as a cast refractory) according to an embodiment of the present invention is used for a melting side wall of a glass melting furnace. A heat insulating plate 2 brought into contact with the outer peripheral surface of the cast refractory, and scanning the heat insulating plate 2 to transmit a pulsed electromagnetic wave toward the molten cast refractory, and a reflected wave of the pulsed electromagnetic wave from the molten cast refractory And an electromagnetic wave probe 3 for receiving.

  Here, the heat insulating plate 2 is used to stabilize the measurement while protecting the electromagnetic wave probe 3 described later. In the measurement, the heat insulating plate 2 is brought into contact with the outer peripheral surface of the side wall of the glass melting furnace, which is the object to be measured, and the electromagnetic wave probe 3 is brought into contact with and scanned with the other contacted surface. That is, the molten cast refractory and the electromagnetic wave probe 3 are brought into indirect contact with each other through the heat insulating plate 2, and the heat insulating plate 2 is high in order to effectively suppress the temperature rise on the electromagnetic wave probe 3 side. Thermal insulation is required.

  In addition, as a material of the heat insulation board 2 used for this invention, the heat insulating material which contains many space | gaps, such as glass wool and ceramic fiber currently used for other uses, is not used. The reason for this is that such a heat insulating material contains a large gap, so that the relative dielectric constant approaches 1. For example, when the side wall, which is the object to be measured, is composed of a cast refractory containing a large amount of zirconia, the relative permittivity of the cast refractory is 10 or more, and the relative permittivity difference from the relative permittivity of the heat insulating material is This is because it gets bigger. As a feature of the electromagnetic wave, the reflectance of the electromagnetic wave is increased at the interface of the substance having a large relative dielectric constant difference. In this case, the reflection of the electromagnetic wave is increased, but the electromagnetic wave transmitted to the inside of the refractory is reduced.

  As mentioned above, the attenuation of the electromagnetic wave transmitted through the molten cast refractory becomes very large at high temperatures, so it is difficult to detect the peak of the reflected wave unless the electromagnetic wave is efficiently sent into the molten cast refractory. turn into. Therefore, it is preferable to suppress an increase in the reflectance of electromagnetic waves at the interface as described above.

  For the above reason, the heat insulating plate 2 used in the present invention is kept at a level at which the peak of the electromagnetic wave reflected on the furnace inner surface of the molten cast refractory can be sufficiently detected while protecting the electromagnetic wave probe 3 from high temperature. Use things. Hereinafter, more specific properties will be described.

  The heat insulating plate 2 used in the present invention is required to have at least heat resistance against the outer peripheral surface temperature of the side wall in order to directly contact the side wall of the high-temperature glass melting furnace. The heat insulating plate 2 is usually required to have a heat resistant temperature of about 250 ° C. at least, and preferably has a heat resistant temperature of 500 ° C. or higher. In addition, since the contact time during measurement is as short as several minutes (preferably several tens of seconds), the heat resistant temperature or a temperature corresponding thereto is sufficient if it has heat resistance within the short time.

  Further, in order to suppress the reflection of electromagnetic waves at the interface between the heat insulating plate 2 and the molten cast refractory during measurement and to transmit the electromagnetic waves to the molten cast refractory side, the relative dielectric constant ε at room temperature (25 ° C.) is 2 to 20 It is as follows. The relative dielectric constant ε is preferably 5 or more, and more preferably 10 or more. On the other hand, the relative dielectric constant ε is preferably 18 or less, and more preferably 15 or less.

Further, in order to effectively suppress the temperature rise to the outside of the heat insulating plate 2 (contact side of the electromagnetic wave probe 3) due to direct contact with the molten cast refractory, the temperature diffusivity (thermal conductivity / heat conductivity ÷ preferably the density ÷ specific heat) is not more than ^{2 × 10 -6 m 2 / sec} , more preferably not more than ^{1 × 10 -6 m 2 / sec} . Thus, by using a preferable material having heat insulation properties, it is possible to prevent the electromagnetic wave probe 3 from being exposed to high heat and to measure stably.

According to the heat transfer calculation, in the case of a 10 mm thick heat insulating plate with a temperature diffusivity of 1 × 10 ⁻⁶ m ² / sec, the initial temperature of the heat insulating plate 2 is made uniform at 20 ° C. Even if it is assumed that the contact surface has instantaneously increased to 600 ° C. due to the contact, the temperature outside the heat insulating plate (contact surface of the electromagnetic wave probe 3) only increases from 20 ° C. to 31 ° C. after 7 seconds. . For this reason, the electromagnetic wave probe 3 is kept within the heat resistant temperature range, and there is no fear of thermal damage of sensors such as an antenna, a transmitter, and a receiver.

  Examples of the heat insulating plate 2 satisfying such characteristics include wood such as veneer plates, glass fiber-containing cement plates, and molten cast refractories. Among them, a heat insulating plate having good thermal resistance, having a temperature diffusivity capable of suppressing the reflection of electromagnetic waves at the interface between the heat insulating plate 2 and the glass melting furnace, and suppressing the transmission of the side wall heat to the electromagnetic wave probe 3 side. Are preferably a glass fiber-containing cement plate and a molten cast refractory. In addition, considering the handleability, a glass fiber-containing cement board that is lighter is particularly preferable. Examples of the glass fiber-containing cement plate include Hemisal 15 (manufactured by NICHIAS, trade name).

Incidentally, the specific example of the characteristic of the said heat insulation board 2 is shown below. The veneer plate, which is wood, has a temperature diffusivity of 3.6 × 10 ⁻⁷ m ² / sec, a relative dielectric constant of 2.2, an ignition temperature of 400 ° C., and the hemisal 15, which is a glass fiber-containing cement plate, has a temperature diffusion. The rate is 3.1 × 10 ⁻⁷ m ² / sec, the relative dielectric constant is 12.0, the heat resistant temperature is 500 ° C., and the molten cast refractory (manufactured by AGC Ceramics Co., Ltd., trade name: ZB-X9510) has a temperature diffusivity. Was 6.0 × 10 ⁻⁷ m ² / sec, the relative dielectric constant was 13.7, and the heat-resistant temperature was 1700 ° C. or higher.

  The heat insulating plate 2 varies depending on the characteristics of the material to be used. For example, the thickness of the heat insulating plate 2 is 10 to 50 mm, and the heat insulating property by the contact with the side wall of the melting furnace is measured on the electromagnetic wave probe 3 side. It is preferable in that sufficient time can be secured and sufficient reflected waves can be obtained by suppressing attenuation of electromagnetic waves.

  The size of the heat insulating plate 2 may be any size as long as the temperature rise of the electromagnetic wave probe 3 can be effectively suppressed. For example, the length in the vertical direction: 150 to 200 mm, the length in the horizontal direction; 150 to 500 mm, Thickness: It is preferable to be a size of 10 to 50 mm. Further, the electromagnetic wave probe 3 can be fixed at the time of measurement and measure the remaining thickness of the refractory at a pinpoint, but continuously by scanning the outer peripheral surface of the molten cast refractory that is the surface to be measured in the horizontal direction. In other words, the remaining thickness of the side wall in the horizontal direction can be measured. In this case, the heat insulating plate has a sufficient length in the lateral direction so that it can be scanned in the horizontal direction.

  Next, the electromagnetic wave probe 3 transmits a pulsed electromagnetic wave toward the molten cast refractory (side wall of the glass melting kiln) that is the surface to be measured, and receives the reflected wave from the molten cast refractory of the pulsed electromagnetic wave. A transmitting antenna 31 for transmitting a pulsed electromagnetic wave, a transmitter 32 for transmitting the pulsed electromagnetic wave from the transmitting antenna 31, a receiving antenna 33 for receiving a reflected wave from the molten cast refractory, and And a receiver 34 that acquires and records the received reflected wave as reflected wave data.

Here, the pulsed electromagnetic wave transmitted from the transmitting antenna 31 preferably has a center frequency of 0.5 to 3 GHz, and more preferably 0.7 to 2 GHz. If the frequency is less than 0.5 GHz, the wavelength of the electromagnetic wave becomes longer, so that a measurement error with respect to the thickness becomes large, and there is a possibility that a measurement accuracy necessary for practical use cannot be obtained. If it exceeds, attenuation of the electromagnetic wave inside the molten cast refractory becomes large, so that it becomes difficult to detect the reflected wave under high temperature conditions, and the measurement is unstable.
In addition, the said frequency is a prescription | regulation by the center frequency to the last, and does not exclude the case where a center frequency is the said range and the frequency band used leaves the said range.

  Then, the transmitter 32 and the receiver 34 transmit the pulsed electromagnetic wave by the transmitter 32, the pulsed electromagnetic wave propagates in the molten cast refractory, and the reflected wave reflected by the inner peripheral surface of the kiln is transmitted. The time until the detection by the receiver 34 (propagation time) can be measured. By applying a predetermined relative dielectric constant to the measured propagation time, it is possible to determine how much remaining molten cast refractory is used on the side wall of the glass melting furnace.

  As the electromagnetic wave probe 3, a known electromagnetic wave probe (for example, product name: NJJ-95A manufactured by Japan Radio Co., Ltd.) used in a concrete internal flaw detector or the like can be used.

  The apparent relative permittivity is obtained by a control test described later. The electromagnetic wave probe 3 is provided with a storage means for storing the apparent relative permittivity, and further using the apparent relative permittivity. It is preferable to provide a calculation means for calculating the remaining thickness from the reflected wave data obtained when the molten cast refractory is measured, because the electromagnetic wave probe 3 alone can calculate the remaining thickness.

  The electromagnetic wave probe 3 can be continuously measured by scanning the heat insulating plate 2, but it is preferable that the contact portion of the electromagnetic wave probe 3 with the heat insulating plate 2 is a tire so that it can move smoothly. . If the tire is provided in this manner, scanning on the heat insulating plate 2 can be stably performed, and measurement can be performed efficiently. In addition, the above-described heat insulating plate 2 and the electromagnetic wave probe 3 may exist physically independently, or may have a structure fixed as an integral object.

  Next, a method for measuring the remaining thickness of the molten cast refractory using the molten cast refractory remaining thickness measuring apparatus 1 will be described.

  Here, about the glass melting kiln which is a measuring object, the sectional side view which is the whole image in FIG. 2 was shown, and the enlarged view of A part in FIG. 2 was each shown. The glass melting furnace 11 melts glass inside and supplies the molten glass 12 to a forming container while flowing. The glass melting furnace 11 is configured by surrounding the upper and lower surfaces and the side walls with a molten cast refractory, and can keep the glass material in a molten state by setting the inside to a high temperature of 1500 ° C. or higher. Here, the molten cast refractory 13 used as the side wall is the object to be measured.

  In measuring the remaining thickness of the molten cast refractory 13 used on the side wall of the glass melting furnace 11, in the present invention, first, a control test using a test furnace is performed, and then the glass melting furnace 11 is used. The remaining thickness will be measured. A flowchart of the operation of the method for measuring the remaining thickness of the molten cast refractory according to the present invention is shown in FIG.

  As shown in FIG. 4, in the present invention, first, the relative dielectric constant is calculated in the control test (S1). The relative dielectric constant calculated at this time is a relative dielectric constant when the molten cast refractory is in a high-temperature heating state so as to match the conditions with the glass melting furnace 11 which is an actual kiln. The relative dielectric constant required here is greatly different in molten cast refractories at room temperature or in different heating conditions. Thus, by obtaining the relative dielectric constant for measurement in advance, the remaining thickness can be measured with little error. .

  The relative dielectric constant calculated here is prepared by preparing a molten cast refractory having the same composition as that of the molten cast refractory 13 constituting the side wall of the glass melting furnace to be a reference molten cast refractory. One surface of the molten cast refractory for heating is heated to substantially the same temperature as the furnace temperature of the glass melting furnace for measuring. The control test is performed using, for example, the test furnace 21 shown in FIG. Here, FIG. 5A is a perspective view of the test furnace 21, and FIG. 5B is a VV cross-sectional view of FIG.

  The test furnace 21 has a heater 22 and a heat insulating material 23a inside (heating side), and a control molten cast refractory 24 can be fixed at the center via the heat insulating material 23b (refractory fixing side). And a test furnace 21b. The heating temperature of the heater 22 is controlled so that the temperature can be detected by a thermocouple 25 provided in the vicinity so that the inside of the furnace can be heated to a predetermined temperature.

  When this test furnace 21 is used, one side of the reference molten cast refractory 24 having a known thickness is heated to a temperature equivalent to the actual furnace temperature by the heater 22, and the control molten cast refractory 24 is heated. The heating state can be approximated to the side wall of the glass melting furnace 11 which is a kiln. The heating temperature at this time is performed in accordance with the temperature in the glass melting furnace to be measured, and the temperature is in a range of ± 150 ° C. with respect to the temperature in the furnace, and is in a range of ± 50 ° C. Is preferred. Also, when the outer surface of the kiln is cooled in an actual kiln, the temperature distribution of the reference molten cast refractory and the actual kiln molten cast refractory is possible by cooling under the same conditions in the test furnace. Try to be as close as possible.

  Then, after sufficiently heating the control molten cast refractory 24 in the test furnace 21, the molten cast refractory is heated from the other surface to be heated of the control molten cast refractory 24 (outer surface of the test furnace 21). The remaining thickness measuring device 1 is used to transmit a pulsed electromagnetic wave toward the reference molten cast refractory 24. At the same time, the reflected wave data from the control molten cast refractory 24 for the transmitted electromagnetic wave is acquired. That is, the heat insulating plate 2 is assigned to the reference molten cast refractory 24, and the electromagnetic wave probe 3 transmits and receives the pulsed electromagnetic wave to and from the reference molten cast refractory 24 via the heat insulating plate 2 to obtain the reflected wave data. get.

  From the obtained reflected wave data, the reflected wave peak from the surface to be heated of the control molten cast refractory 24 (the inner surface of the test furnace) can be identified from the transmission of electromagnetic waves. From this reflected wave peak, the time difference (propagation time) from the transmission of the electromagnetic wave to the reception of the reflected wave can be found, and the apparent material and thickness of the combined molten cast refractory 24 for control and the heat insulating plate 2 at this time are apparent. The relative dielectric constant εp can be obtained by the following equation.

  The thickness D of the reference molten cast refractory by the electromagnetic wave explorer 3 is obtained by receiving the reflected wave from the electromagnetic wave velocity V in the reference molten cast refractory and the transmission time of the electromagnetic wave transmitted to the reference molten cast refractory. It can be obtained from (Equation 1) from the time difference T up to the time.

この式において、Ｖは（数２）により求められる。

In this equation, V is obtained by (Equation 2).

ここで、Ｃは真空中（空気中）での電磁波の速度（３×１０^８ｍ／ｓ）であり、εｐは対照用溶融鋳造耐火物（断熱板込み）の比誘電率である。

Here, C is the speed of electromagnetic waves (3 × 10 ⁸ m / s) in vacuum (in the air), and εp is the relative dielectric constant of the control molten cast refractory (including a heat insulating plate).

  In the above-mentioned control test, D is the thickness obtained by combining the control molten cast refractory 24 and the heat insulating plate 2 and is a known value, and T is a value measured by the electromagnetic wave probe 3, The time difference from the transmission to reception of the reflected wave is used as it is. C is a constant as described above. Therefore, by performing the above-described control test, it is possible to calculate the apparent relative dielectric constant εp of the control molten cast refractory and the heat insulating plate in the heated state.

  In addition, as the melt-cast refractory 24 for control, since the accuracy of measurement is further improved by combining with the eroded situation of the melt-cast refractory 13 used in the glass melting furnace 11 which is a real kiln, What was cut out from a cast refractory is preferred. This is because the refractory obtained by melt casting is generally not completely uniform in composition and structure, and when it is melted and poured into a mold and cooled and solidified, the cooling rate varies depending on the location. This is because there are differences in crystal size, composition, etc. for the reason.

  As shown in FIG. 6 (a), for example, in the case of a molten cast refractory obtained by melt casting, in the vicinity of the surface layer, the cooling rate is high, the crystal size is small, and the concentration is slightly different from the inside. It is formed as a different quenching part 13a. Further, the inside thereof is formed as a gradually cooled portion 13b that is gradually cooled and has a large crystal size and a high concentration, unlike the vicinity of the surface layer. And this is used as a side wall of the glass melting furnace 11 as it is.

  In other words, when this is applied to an actual kiln, the operation is initially started with a cross section as shown in FIG. 6 (a), but by continuing the operation, the side of the glass melting kiln in contact with the molten glass is changed. The molten cast refractory is gradually eroded and thinned as shown in FIG. 6B, and further erosion proceeds as shown in FIG. 6C.

  That is, since the molten cast refractory 13 to be measured in the present invention is in a thin state as shown in FIG. 6B or 6C, in order to perform more accurate measurement, It is formed so as to have the same thickness as the molten cast refractory 13 before operation shown in FIG. 6 (a), and one side as shown in FIG. 6 (b) and FIG. Is preferably used as a control melt cast refractory. In this way, the measurement error can be further reduced by considering the part used at the time of arranging the refractory in the actual kiln and conducting the test in the same part and the arrangement condition.

  Next, the remaining thickness of the molten cast refractory that is the side wall of the melting kiln that is a real kiln is measured (S2).

  3 is a partially enlarged cross-sectional view of a broken line portion A of the glass melting furnace 11 of FIG. As shown in FIG. 3, one surface of the heat insulating plate 2 is brought into contact with the surface to be measured of the molten cast refractory 13 to be measured, and the electromagnetic wave probe 3 is brought into contact with the heat insulating plate 2 while horizontally ( In FIG. 3, scanning is performed in the front-rear direction. In this horizontal scanning, the position of the electromagnetic wave probe 3 is preferably the height of the interface of the molten glass 12 in the glass melting furnace. This is because the side wall of the melting furnace is easily eroded at the interface of the molten glass, and the thickness is thinner than other parts, which is suitable for determining whether the melting furnace is stopped.

  Then, by this scanning, the transmitter 32 of the electromagnetic wave probe 3 continuously transmits a predetermined electromagnetic wave from the transmission antenna 31 toward the molten cast refractory 13 that is the surface to be measured, and at the same time, the molten casting of the electromagnetic wave. The reflected wave from the refractory 13 is received by the receiving antenna 33, the reception state is detected by the receiver 34, and the reflected wave data of the electromagnetic wave is acquired.

  Next, the position of the reflected wave peak from the inner peripheral surface of the molten cast refractory is determined based on the obtained reflected wave data (S3). This reflected wave peak usually appears as the largest waveform, and the reflectivity at the interface between the molten cast refractory and the glass substrate is a positive value due to the relative dielectric constant between the molten cast refractory and the glass substrate. Therefore, it can be easily determined by considering the phase of the reflected wave.

  And if the position of the reflected wave peak from a kiln internal peripheral surface can be determined, the thickness of the fusion | melting cast refractory material including a heat insulation board will be calculated from the measurement time of the reflected wave in the position (S4). Specifically, since the time difference between the transmission time of the electromagnetic wave and the measurement time of the reflected wave peak is the propagation time of the electromagnetic wave, if this is applied to T in (Equation 1), V can be calculated in the control test. The thickness D can be calculated. However, the thickness calculated here is the combined thickness of the molten cast refractory 13 and the heat insulating plate 2.

  Next, the thickness of the molten cast refractory 13 alone is calculated (S5). This is because the thickness including the heat insulating plate has already been calculated in S4, and the thickness of the heat insulating plate 2 is already known. Therefore, the thickness of the heat insulating plate 2 actually used is subtracted from the calculated thickness. Thus, the remaining thickness of the molten cast refractory 13 alone can be calculated.

  The steps of S1 to S5 can be continuously measured at a plurality of locations by scanning the electromagnetic wave probe 3 in the horizontal direction, and the respective thicknesses can be calculated by the same steps at each measurement location. Thereby, the state of the inner peripheral surface of the glass melting furnace 11 can be grasped.

  In the above method, the remaining thickness of the molten cast refractory 13 is calculated in steps S4 and S5. However, in S4, the position of the reflected wave peak at the interface between the heat insulating plate 2 and the molten cast refractory 13 is completely set. Since the time difference between the reflected wave peak and the reflected wave peak of the inner peripheral surface of the molten cast refractory 13 corresponds to the propagation time of electromagnetic waves reciprocating the thickness of the molten cast refractory 13 alone, The remaining thickness of the molten cast refractory 13 may be calculated from this time difference.

[Second Embodiment]
Next, a second embodiment of the present invention will be described.
In the second embodiment, a plurality of relative dielectric constants in the control test are calculated by changing the thickness of the molten cast refractory for control, and the thickness of the molten cast refractory to which the obtained multiple relative dielectric constants are applied. This is different from the first embodiment in that each thickness is calculated and the most suitable thickness among the calculated thicknesses is determined as the thickness of the molten cast refractory.

  Although the flowchart of this embodiment is shown in FIG. 7, the same operation as S2 to S4 of the first embodiment is performed from S12 to S14. S16 is a step corresponding to S5, and performs the same operation. Hereinafter, the difference will be mainly described.

  In this embodiment, first, the relative dielectric constant is calculated in the control test as in S1 of the first embodiment (S11). However, in the present embodiment, a plurality of relative dielectric constants are calculated as described below.

This is because it is not known how much the remaining thickness of the molten cast refractory in the actual kiln is, so in the control test, the relative permittivity of each of the molten cast refractories with multiple thicknesses is calculated. It is something to keep. For example, as the control molten cast refractory, the relative dielectric constants εp ₁ , εp ₂ , εp of the control molten cast refractories including the heat insulating plate having the thickness (Tα) of 40 mm, 70 mm, 100 mm, and 130 mm, respectively. ₃ and εp ₄ are obtained in advance.

  The actual kiln measurement (S12), the actual kiln inner peripheral surface peak position determination (S13), and the thickness calculation including the heat insulating plate (S14) are performed by the same operation in steps corresponding to S2 to S4, respectively. However, the relative dielectric constant used in S14 uses all of the plurality of relative dielectric constants calculated in S11, and obtains the thickness when each relative dielectric constant is applied.

  In the present embodiment, it is determined which numerical value is most appropriate for the converted thickness (Tβ) of the molten cast refractory including the heat insulating plate calculated in S14 (S15). Here, the absolute value is calculated from the thickness (Tα) of the reference molten cast refractory including the heat insulating plate and the calculated thickness (Tβ) of the molten cast refractory calculated as the basis of the relative dielectric constant used for each calculation. | Tα−Tβ | is calculated, and the smallest value is determined as the optimum value, and this is determined as the thickness of the molten cast refractory including the refractory.

  At this time, the absolute value is preferably within 5.0 mm, and if it is larger than that, it is desirable that the error be large and that the measurement conditions be changed again.

  Then, the remaining thickness of the molten cast refractory 13 alone is calculated (S16). This is a step corresponding to S5 of the first embodiment, and is performed by removing the thickness of the heat insulating plate from the converted thickness of the molten cast refractory 13 including the heat insulating plate determined in S15 by the same operation. Just do it.

  According to this embodiment, the remaining thickness of the molten cast refractory can be measured with less error, and it is possible to optimize the judgment of whether or not to operate the glass melting furnace.

  Hereinafter, based on the above-described second embodiment, a thickness calculation example in the case where the relative permittivity for a plurality of thicknesses is obtained by a control test is shown below. Here, when two types of relative dielectric constants are used, for example, the case where the thickness of a reference molten cast refractory including a heat insulating plate (hereinafter referred to as Tα) is 70 mm and 100 mm is described. To do.

  First, the apparent relative dielectric constant εp of each thickness is obtained. When the thickness changes in this way, the relative dielectric constant changes due to changes in the volume ratio between the heat insulating plate and the molten cast refractory, changes in the temperature distribution of the kiln, and the like. The obtained results are shown in Table 1.

  And each conversion thickness T (beta) is calculated from the reflected wave data by the measurement in a real kiln, and the relative permittivity obtained above from the time difference from transmission of an electromagnetic wave to reception of a reflected wave. At this time, the absolute value of the difference between Tα and Tβ is also calculated. The absolute values of the obtained differences are compared, it is determined that the data having the smallest absolute value is appropriate, and the converted thickness Tβ to be used is determined. The results are shown in Table 2.

  Here, when Tα is 70 mm thick, the absolute value is 30.3 mm, and when Tα is 100 mm thick, the absolute value is 1.8 mm, which is based on a 100 mm thick reference molten cast refractory with a small absolute value. Judge that the calculated value is appropriate. Finally, the thickness of the heat insulating plate is subtracted from the converted thickness Tβ to obtain the remaining thickness of the molten cast refractory.

Even when a plurality of relative dielectric constants are used, the above-described method for determining the remaining thickness is an example. As another method for determining the remaining thickness, a change in εp with respect to Tα is not a change that has an extreme value. As long as monotonous increase or monotonic decrease, a mathematical solution such as an iterative method may be used, or a value between thickness data may be interpolated by linear interpolation or the like.
At least as far as the molten cast refractories shown in the examples are concerned, no change is observed in which the change in εp with respect to Tα has an extreme value, and according to the second embodiment, what is the remaining thickness of the molten cast refractory? Even a thickness can be measured with higher accuracy.

  According to the second embodiment, the thickness of the molten cast refractory can be measured with higher accuracy regardless of the thickness, but in terms of determining the use limit of the glass melting furnace, the first In the embodiment, if the control molten cast refractory is used with a thickness similar to the use limit, there is no problem because the calculated value at the limit value is appropriate.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited at all by these description.

The melt-cast refractory used in the examples is a melt-cast refractory for glass melting kiln (trade name: ZB-X9510, manufactured by AGC Ceramics) containing about 95% zirconia component. The size of the control molten cast refractory used for the relative permittivity measurement is 400 mm × 200 mm × 60 mm, and the mass of one piece is about 26 kg.

  As the test furnace, the test furnace which is a control test facility for measuring the relative dielectric constant shown in FIG. 5 was used. Although the low temperature portion corresponding to the outer surface of the furnace is in contact with the outside air, the temperature inside the furnace and the temperature outside the furnace are further reduced by performing forced air cooling on the outer surface of the furnace as in the actual glass melting furnace. The temperature is controlled.

  As an electromagnetic wave probe, a radar NJJ-95A (trade name) manufactured by Japan Radio Co., Ltd. was used. This apparatus is provided with a memory card, and can store reflected wave data as a measurement result. The obtained data was processed by an external computer to detect the reflected wave peak position and calculate the remaining thickness of the molten cast refractory.

  Using the test furnace shown in FIG. 5, with the 60-mm-thick control molten cast refractory fixed to a single-sided heating furnace, the test furnace temperature was heated to 1500 ° C., the same as the furnace temperature of the glass melting furnace to be measured. When the outer surface was subjected to forced air cooling, the furnace outer surface temperature of the molten cast refractory was 480 ° C.

In this state, on the surface of the control molten cast refractory outside the furnace, a veneer plate having a thickness of 170 mm × 300 mm × 15 mm; temperature diffusivity: 3.6 × 10 ⁻⁷ m ² / sec, relative dielectric constant: 2.2 , Ignition temperature: 400 ° C.), and before the temperature of the veneer plate rose, the electromagnetic wave probe was quickly brought into contact with the surface of the veneer plate and measured. Here, the temperature diffusivity of the veneer plate is the density of the veneer plate 500 [kg / m ³ ], the thermal conductivity 0.18 [W / (m · K)], and the specific heat 1000 [J / kg / K]. As calculated.

  As described above, the outer surface temperature of the reference experimental furnace is 480 ° C., which exceeds the ignition temperature of the veneer plate of 400 ° C. However, since the measurement actually ended within 5 seconds, the measurement itself could be carried out without any problem. However, a phenomenon such as scorching of the end of the veneer plate is observed, and it is desirable to use a heat insulating plate with higher heat resistance, which will be described later in Example 2.

  In this measurement, an electromagnetic wave probe transmits an electromagnetic wave having a center frequency of 0.9 GHz to a reference molten cast refractory through a heat insulating plate, and receives a reflected wave of the electromagnetic wave from the molten cast refractory. The reflected wave data was obtained. The reflected wave data when the electromagnetic wave of the electromagnetic wave probe is transmitted is obtained as image data indicating the relationship between the time elapsed since the transmission and the waveform of the reflected wave. For the obtained reflected wave data, using the (Equation 1) and (Equation 2) from the peak position (propagation time) of the reflected wave and the thickness of the molten cast refractory for control and the heat insulating material, The apparent dielectric constant included was calculated to be εp = 15.7. FIG. 8 shows the relationship between the reflected wave peak and the converted thickness of the control molten cast refractory including the heat insulating plate when the apparent relative dielectric constant εp is 15.7. The broken line is the position of the reflected wave peak, and the same applies to the reflected wave data below.

  First, based on this example, it will be described that the attenuation of electromagnetic waves inside the molten cast refractory increases when the temperature of the molten cast refractory rises. FIG. 9 shows the results of measurements similar to those in the high temperature control test of FIG. 8 performed at room temperature. Although the reflected wave peak in FIG. 9 is very large and clear, the reflected wave peak in FIG. 8 is very small. This is because, as described above, the attenuation of electromagnetic waves in the molten cast refractory increases at a high temperature. For example, if the same measurement is performed step by step in the course of raising the temperature from room temperature to 1500 ° C., the reflected wave peak in FIG. 9 gradually decreases and approaches FIG. 8, and the peak in FIG. It is known that it is a back reflection wave peak.

  However, if the dielectric constant of the heat insulating plate is further reduced, the interface reflection with the molten cast refractory is increased, or if the brick thickness is increased and the electromagnetic wave attenuation inside the brick is increased, the reflection on the back surface is further increased. There is a possibility that the wave peak becomes small and the peak cannot be detected. For this reason, it is important to send electromagnetic waves as efficiently as possible to the molten cast refractory to be measured, and it is necessary to use a heat insulating plate having a relative dielectric constant in the range described above.

  Moreover, it demonstrates that the dielectric constant of a molten cast refractory changes with temperature based on this Example. From the result at room temperature in FIG. 9, the apparent dielectric constant including the heat insulating plate was calculated, and εp = 9.8. In the case of the high temperature shown in FIG. 8, since εp = 15.7, it can be seen that the value of the relative dielectric constant becomes completely different as the temperature rises. For this reason, in order to measure the remaining thickness in an actual kiln, measurement with little error cannot be performed unless the relative permittivity is measured under high temperature conditions close to the actual kiln state.

  Next, the measurement was performed immediately before the end of the kiln of the plate glass actually operated. About this glass melting furnace, as shown in FIG. 3, it measured in the height of the liquid level of the molten glass 12 of the molten cast refractory 13 which is a side wall. By applying εp = 15.7 of the control test to the reflected wave data obtained by the actual kiln measurement, the converted thickness including the heat insulating plate was calculated from the measurement time (propagation time) of the reflected wave peak. The results are shown in FIG.

  From this result, the remaining thickness of the measurement location of the plate glass kiln was measured as 72 mm (peak position) −15 mm (heat insulating plate thickness) = 57 mm. The kiln was stopped within a few days after the measurement was performed, and after entering the kiln, the remaining thickness of the measurement site was confirmed. As a result, the error between the measurement result due to electromagnetic waves and the actual thickness was +3 mm. It was. By using the present invention as described above, since the remaining thickness of the molten cast refractory having a thickness of at least 50 mm or more during hot use can be measured with high accuracy (for example, about ± 5.0 mm), the kiln is stopped. Therefore, it is possible to make an appropriate decision on repair execution.

  In Example 2, a control test was performed under substantially the same conditions as in Example 1. The difference from Example 1 is the thickness of the molten cast refractory and the type of heat insulating plate. The thickness of the molten cast refractory was 90 mm. The size is 400 mm × 200 mm × 90 mm, and the mass of one piece is about 39 kg. Moreover, in Example 2, in order to improve the heat resistance problem of the heat insulating plate described in Example 1 and the point of efficiently sending electromagnetic waves to the molten cast refractory, the heat resistance is higher and the relative dielectric constant is higher. The following insulation board was used.

Glass fiber-containing cement board (manufactured by NICHIAS, trade name: Hemisal 15: temperature diffusivity is 3.6 × 10 ⁻⁷ m ² / sec, relative permittivity is 12.0, heat resistance is 500 ° C.)
The size used is 170mm x 450mm x 10mm thick.

As in Example 1, when the furnace temperature was heated to 1500 ° C. and forced air cooling was performed on the outer surface, the furnace outer surface temperature of the molten cast refractory was 408 ° C.
Further, when the apparent relative dielectric constant including the heat insulating plate was calculated in the same manner as in Example 1, εp = 17.4 was obtained. FIG. 11 shows the relationship between the reflected wave peak and the converted thickness of the control molten cast refractory including the heat insulating plate when the apparent relative dielectric constant εp is 17.4.

  Next, measurement was carried out in a plate glass kiln that was actually operated. As shown in FIG. 3, the glass melting furnace was continuously measured by scanning the electromagnetic wave probe in the horizontal direction at the height of the liquid surface of the molten glass 12 of the molten cast refractory 13 as the side wall. The measurement which changed the position of the heat insulation board was implemented 3 times in total. When changing the position of the heat insulating material, there was an overlap with the previous measurement, and the displacement was grasped, and these measurement results were connected on a computer. As a result, the reflected wave peak covering about 700 mm in the longitudinal direction across the joint of the molten cast refractory was continuously captured. By applying εp = 17.4 of the control test to the reflected wave data obtained by the actual kiln measurement, the converted thickness including the heat insulating plate was calculated from the measurement time (propagation time) of the reflected wave peak.

  About this conversion thickness, it calculated in all the several measurement points when it scanned, and subtracted the thickness of the heat insulation board from the obtained conversion thickness, and calculated the remaining thickness of each molten cast refractory. The remaining thickness of the obtained molten cast refractory is shown in FIG. 12 with the horizontal distance obtained by scanning the horizontal axis being the horizontal axis and the remaining thickness of the molten cast refractory being the vertical axis. The horizontal axis represents the distance in the horizontal direction, but the joint of the molten cast refractory is represented as 0 point.

  From this result, the remaining thickness of the molten cast refractory is 90 mm in the thinnest part near the joint. Since the actual thickness is in operation, it is known that it is only a measured value by inserting a difference from the joint and is at least 70 mm or more, but the absolute value could not be confirmed.

  On the other hand, it has been measured that the molten cast refractory is becoming thinner toward the joints with respect to the relative thickness change depending on the location. In the observation when the normal glass melting furnace is stopped, the horizontal thickness distribution is generally that the remaining thickness of the joint part is thinner than the remaining thickness of the other part, and the same during operation It can be inferred that this is a thickness distribution.

  In addition, the left brick has a smaller residual thickness than the right brick, but it is confirmed that the temperature of the molten glass in contact with the brick is higher in the left brick even in an actual furnace. It can be easily guessed that erosion proceeds faster with the left brick. From the above, it was confirmed that this measurement result is valid for the relative change of the remaining thickness depending on the location. As described above, being able to grasp the difference in the amount of erosion depending on the location leads to identification of a location with a high possibility of substrate leakage, which is extremely useful information from the viewpoint of preventing glass substrate leakage accidents.

  As described above, by using the present invention, the remaining thickness of a molten cast refractory having a thickness of at least 50 mm or more during hot use can be measured with high accuracy (for example, about ± 5.0 mm). Because it is possible to find the thinned part, it is possible to appropriately judge whether to stop the furnace or to repair it.

  The present invention is a measuring method and measuring apparatus effective for measuring the thickness of a molten cast refractory in a high temperature state, and is extremely effective for measuring the remaining thickness of a molten cast refractory whose thickness changes over time. It is.

DESCRIPTION OF SYMBOLS 1 ... Melt cast refractory residual thickness measuring apparatus, 2 ... Thermal insulation board, 3 ... Electromagnetic wave probe, 31 ... Transmitting antenna, 32 ... Transmitter, 33 ... Receiving antenna, 34 ... Receiver, 11 ... Glass melting furnace, 12 ... molten glass, 13 ... melt cast refractories

Claims (8)

A method for measuring a remaining thickness of a molten cast refractory used on a side wall of a glass melting furnace, wherein one side of a reference molten cast refractory having the same composition as the molten cast refractory to be measured is melted into the glass While heating to a temperature almost the same as the temperature in the kiln of the kiln, the other surface of the reference molten cast refractory has a heat-resistant temperature of 250 ° C. or higher, a relative dielectric constant of 2 to 20, and a temperature diffusivity of 2 ×. A step of contacting a heat insulating plate of 10 ⁻⁶ m ² / sec or less and transmitting a pulsed electromagnetic wave having a center frequency of 0.5 to 3 GHz toward the control molten cast refractory through the heat insulating plate;
Obtaining reflected wave data from the heated side surface of the reference molten cast refractory of the pulsed electromagnetic wave to determine an apparent relative dielectric constant of the reference molten cast refractory;
On the outer peripheral surface of the molten cast refractory to be measured in the glass melting kiln, a heat insulating plate having a heat resistance temperature of 250 ° C. or higher, a relative dielectric constant of 2 or more and 20 or less, and a temperature diffusivity of 2 × 10 ⁻⁶ m ² / sec or less. And transmitting an electromagnetic wave having the same frequency as the pulsed electromagnetic wave transmitted to the control molten cast refractory through the heat insulating plate toward the molten cast refractory to be measured,
Obtaining reflected wave data from the inner peripheral surface of the molten cast refractory of the pulsed electromagnetic wave;
Based on the propagation time of the pulsed electromagnetic wave in the molten cast refractory obtained from the reflected wave data of the pulsed electromagnetic wave, and the apparent relative dielectric constant obtained for the reference molten cast refractory, the remaining molten cast refractory is determined. Calculating the thickness;
A method for measuring a remaining thickness of a molten cast refractory, comprising: In the control test, a plurality of apparent relative dielectric constants were obtained using a plurality of control melt cast refractories having different thicknesses,
In the step of calculating the remaining thickness of the molten cast refractory, the remaining thickness of the molten cast refractory is calculated by applying a plurality of apparent relative dielectric constants, respectively.
The remaining thickness of the plurality of obtained molten cast refractories is determined as the remaining thickness with the smallest difference from the thickness of the reference molten cast refractory used as the basis for calculating the relative dielectric constant used. The method for measuring the remaining thickness of the molten cast refractory as described.   The molten cast refractory according to claim 2, wherein a difference between the remaining thicknesses of the plurality of obtained molten cast refractories and the thickness of the reference molten cast refractory used as a basis for the calculation is within ± 5.0 mm. Residual thickness measurement method.   The method for measuring the remaining thickness of a molten cast refractory according to any one of claims 1 to 3, wherein the calculation of the remaining thickness is continuously performed while scanning in a horizontal direction with respect to the surface to be measured. When measuring the remaining thickness of the molten cast refractory used for the side wall of the glass melting furnace, the heat resistance temperature is 250 ° C. or higher, the relative dielectric constant is 2 or higher, and 20 or lower, the temperature diffusion. A heat insulating plate having a rate of 2 × 10 ⁻⁶ m ² / sec or less,
A transmitter for transmitting a pulsed electromagnetic wave from the transmitting antenna toward the outer peripheral surface of the molten cast refractory through the heat insulating plate, and a reflected wave of the pulsed electromagnetic wave from the molten cast refractory is received by the receiving antenna. An electromagnetic wave probe having a receiver for acquiring reflected wave data,
An apparatus for measuring the remaining thickness of a molten cast refractory, comprising: In the measurement of the remaining thickness of the molten cast refractory, storage means for storing the relationship between the thickness of the reference molten cast refractory and the relative dielectric constant;
A calculation means for measuring the remaining thickness of the molten cast refractory by applying a relative dielectric constant stored in the storage means for the reflected wave data obtained from the molten cast refractory by the electromagnetic wave probe,
The apparatus for measuring a residual thickness of a molten cast refractory according to claim 5.   The apparatus for measuring a remaining thickness of a molten cast refractory according to claim 5 or 6, wherein the heat insulating plate is a glass fiber-containing cement plate.   The residual thickness measuring apparatus of the molten cast refractory according to any one of claims 5 to 7, wherein a tire is provided on the heat insulating plate contact surface of the electromagnetic wave explorer.

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