JP5146673B2 - ALC panel main bar cover thickness inspection method - Google Patents

Description

  The present invention relates to a method for inspecting the rebar cover thickness of an ALC (lightweight aerated concrete) panel used as an outer wall material of a building, for example, particularly the cover thickness of a main rebar.

  In the manufacture of ALC panels, in general, a raw material slurry mainly composed of silica, quicklime, cement, etc. and aluminum powder as a blowing agent are added and injected into a formwork in which reinforcing bars are arranged. Take a lightweight foam concrete block that has been foamed, cured, and semi-cured from the formwork, and cut it into a panel of a predetermined size with a wire made of piano wire, etc. To do. Next, the cut semi-cured ALC panel is steam-cured with an autoclave, and then subjected to surface treatment as appropriate to produce a product.

  As described above, inside the normal ALC panel, reinforcing reinforcing bars which are formed by welding reinforcing bars into a bowl shape are arranged. For example, FIG. 2 shows a perspective view of an ALC panel that is generally called a thick panel and has a thickness of 75 mm to 200 mm in a partially broken state so that reinforcing bars inside the panel appear. As shown in the figure, the reinforcing reinforcing bars are constituted by a main reinforcing bar (2), a horizontal reinforcing bar (3), and a vertical reinforcing bar (4).

  The main muscle (2) is parallel to the abdominal surface (1a) of the ALC panel (1), extends in the longitudinal direction of the ALC panel (1), and is equidistant from the abdominal surface (1a) of one (for example, the outer wall surface). It consists of two groups consisting of one group and the other group equidistant from the other abdominal surface (1a).

  The transverse reinforcing bars (3) are parallel to the abdominal surface (1a) and welded to the inner side in the thickness direction of the ALC panel in a state orthogonal to the main reinforcing bars (2) of the two groups. Is done. The longitudinal reinforcing bars (4) are perpendicular to the abdominal surface (1a), and both ends are welded to the two main reinforcing bars (2) on the outer side in the width direction of the ALC panel.

  The main reinforcement (2) has a diameter of about 5 mm to 8 mm, and the transverse reinforcement (3) and the longitudinal reinforcement (4) have a diameter of about 3 mm to 5 mm.

  The reinforcing reinforcing bar having such a configuration is obtained by first joining the main reinforcing bar (2) and the horizontal reinforcing bar (3) by welding at the intersection (5) to form two grid-like mats. It is manufactured by welding and joining with a vertical reinforcing bar (4) and molding it into a bowl shape.

  A predetermined cover thickness (in the case of the main reinforcement (2), the distance between the abdominal surface (1a) and the main reinforcement (2)) is provided between the surface of the ALC panel and the reinforcing reinforcing bars. The cover is provided so that the reinforcing reinforcing bar function of maintaining the strength of the ALC panel works effectively. For example, the ALC panel shown in FIG. 2 is usually provided with a cover thickness of a main bar of 7.5 mm or more.

  However, in the process of manufacturing reinforcing bars or in the process of placing them in the mold for manufacturing ALC panels, for some reason, the position of the reinforcing bars, especially the main bar (2), exceeds the allowable value with respect to the outer shape. May be displaced.

Due to such displacement, the cover thickness of the reinforcing bar, which is the distance between the surface of the ALC panel and the reinforcing bar, fluctuates and becomes less than the above value, or the reinforcing bar is exposed from the surface. Along with quality, it becomes a problem of appearance. Therefore, it is necessary to exclude from the product that the cover thickness is less than the above value as an abnormal cover thickness.
Conventionally, as described in Patent Documents 1 to 4, for example, an eddy current magnetic sensor composed of an excitation coil and a detection coil is used to determine the distance between the facet and the end of the lateral reinforcement (3). Non-contact measurement is performed. This is because the eddy current excited in the reinforcing bar by the excitation coil to which the high-frequency current is applied is used to calculate the output voltage value of the detection coil and the distance between the reinforcing bar that is the measured object and the eddy current type magnetic sensor. From the relative relationship, the burying position of the reinforcing reinforcing bars is confirmed.

  The reinforcing bar cover thickness can also be inspected by measuring the distance between the main bar (2) and the abdominal surface (1a) by bringing the eddy current type magnetic sensor close to the surface of the ALC panel. There is also a dedicated non-destructive device for measuring the rebar cover thickness in concrete using such an eddy current magnetic sensor.

However, these dedicated devices have a high product cost and are not suitable for measurement in a high speed state during transportation. Therefore, these dedicated devices cannot be used for checking the reinforcing bar cover thickness of ALC panels produced in large quantities.
Japanese Patent No. 3116823 JP-A-10-185506 JP-A-10-293002 JP 2003-315004 A

  The object of the present invention is to use a simple excitation coil and a detection coil instead of a dedicated device to measure the reinforcing bar cover thickness, especially the main bar cover thickness from the main bar to the abdominal surface embedded in the ALC panel manufacturing process. An object of the present invention is to provide a method for measuring at high speed and inexpensively using a current type magnetic sensor.

  The main bar cover thickness measuring method for an ALC panel according to the present invention is a method for measuring the cover thickness from the abdominal surface of the ALC panel to the main bar that is linearly conveyed in the horizontal direction, and is a vortex using an excitation coil and a detection coil. Using an electric current type magnetic sensor, the eddy current type magnetic sensor is held at a constant distance (L) from the abdominal surface of the ALC panel and at a constant speed (v1) with respect to the transport direction of the ALC panel. The output value of the eddy current type magnetic sensor is output as an analog signal, the peak value (vm) of the measurement signal when the eddy current type magnetic sensor passes over the main muscle, and the speed (V1) and a relational expression f (peak value, speed) of the distance between the eddy current magnetic sensor and the main muscle are obtained in advance, and the cover thickness (t) of the main muscle is t = f (vm, v1). -L is calculated by L .

  Two or more eddy current type magnetic sensors are provided in a direction perpendicular to the transport direction of the ALC panel, and the width of the ALC panel is reduced by the two or more eddy current type magnetic sensors with respect to one ALC panel. It is preferable to measure by dividing in the direction.

  Further, by performing peak cut processing or moving average processing on a plurality of continuous peak values for each main muscle extending in the transport direction in one ALC panel obtained from the analog output, the main muscle is obtained. It is preferable to remove the influence of the excessive peak value caused by the reinforcing reinforcing bars intersecting with.

  In the distribution of the cover thickness of the main muscle obtained by the measurement method described above, when the cover thickness closest to the abdominal surface exceeds a predetermined value, it can be determined that the main muscle cover thickness is abnormal.

  According to the present invention, the cover thickness can be measured at high speed by using an inexpensive eddy current type magnetic sensor in the manufacturing process of the ALC panel without using a commercially available expensive dedicated machine. Further, by suppressing overdetection, it is possible to prevent a decrease in reliability.

  Furthermore, the effect that the information regarding the position of the main muscle can be used as data in the process management can be obtained.

  The main bar cover thickness inspection method for the ALC panel of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the concept of main bar cover thickness measurement of an ALC panel according to the present invention. FIG. 2 is a partially broken perspective view of an ALC panel generally referred to as a thick panel to which the present invention is applied and having a thickness of 75 mm to 200 mm. FIG. 3 is a cross-sectional view of the ALC panel of FIG.

  In the main bar cover thickness measuring method for an ALC panel according to the present invention, the ALC panel (1) is conveyed linearly in a horizontal direction at a constant speed (v0) by a known conveying device (not shown).

  In the present invention, an eddy current magnetic sensor (7) using an excitation coil and a detection coil is used for such measurement. A well-known thing can be used for this eddy current type magnetic sensor.

  The eddy current type magnetic sensor (7) is fixed in a direction perpendicular to the transport direction at a position away from the ALC panel (1) by a certain distance (L) above the transported ALC panel (1). Reciprocating at a speed (v1).

  For this purpose, the eddy current type magnetic sensor (7) may be attached to a motion mechanism (not shown) that performs the above motion. This motion mechanism may be configured by a known technique, for example, configured to reciprocate a predetermined distance, for example, a distance longer than the width direction of the ALC panel (1) by a known linear technique. .

  In the present invention, the output value of the eddy current type magnetic sensor (7) is analog-output. For such analog output, well-known techniques and devices (such as a monitor and a printer) can be used.

  In the present invention, in the change in the output value of the obtained measurement signal, the detected value indicates that the eddy current type magnetic sensor (7) has approached the main muscle (2) when passing over the main muscle (2). The relational expression f (detection value and speed of measurement signal) of the peak value (vm), the speed (v1) of the eddy current type magnetic sensor, and the distance between the eddy current type sensor (7) and the main muscle (2) is obtained in advance. Keep it.

  Thereby, the cover thickness (t) of the main reinforcement (2) can be calculated by t = f (vm, v1) −L.

  This point will be described in more detail.

  The output of the eddy current type magnetic sensor (7) is obtained, for example, as shown in FIG. FIG. 6 is a graph showing the sensor output with respect to the moving speed when passing over the main muscle. The lowest vertex of the output voltage (V) is the peak value. Thus, when passing through the main muscle, the detection value appearing in the sensor output changes with respect to the moving speed. For example, the result shown in FIG. 6 is that an eddy current sensor with a voltage output with a fixed detection surface is attached so that the detection surface is perpendicular to the traveling direction of the single-axis servo actuator. The main muscle is fixed at a right angle so that the distance from the detection surface to the main muscle surface is 5 mm, and the actuator is swirled when the sensor traverses the main muscle at a speed of 50 mm / s, 100 mm / s, 150 mm / s, 200 mm / s. It is an output value for each moving speed when the moving speed of the current type magnetic sensor (7) is changed.

  Therefore, as shown in FIG. 7, which is a graph showing the relationship between the peak of the detected value (peak value) and the distance between the eddy current magnetic sensor and the main muscle, using the moving speed as a parameter, the distance relational expression f (measurement signal detection Value, speed).

  As a result, the cover thickness (t) of the main bar (2) can be obtained by measuring the peak value (vm) of the measurement signal when passing over the main bar (2) and the eddy current magnetic sensor ( 7) and the speed (v1) can be calculated and measured as t = f (vm, v1) −L.

  When a single eddy current type magnetic sensor (7) is used, the eddy current type magnetic sensor (7) reciprocates in a direction perpendicular to the conveying direction of the ALC panel. When the ALC panel is transported in this state, the eddy current magnetic sensor (7) draws a locus as shown in FIG. 4 with respect to the ALC panel (1).

  As shown in FIG. 3, the ALC panel (1) has a cover thickness (6a, 6b) that is the distance from the abdominal surface (1a) to the main muscle (2), and is affected by the bending of the main muscle (2). It may come off and become too close to the abdominal surface (1a). Therefore, such an abnormality can be detected by monitoring the output of the eddy current type magnetic sensor (7). Note that the ALC panel shown in FIG. 3 is drawn to include an abnormal state for the sake of explanation.

  In general, as shown in FIG. 3 (a), an abnormality in the cover thickness of the main muscle has a tendency that the main muscle (2) is biased as a whole with respect to the abdominal surface (1a), or in FIG. 3 (b). As shown, one end (the other end on the opposite surface) approaches the abdominal surface (1a), or the main muscle (2) is gently curved along the way as shown in FIG. 3 (c). Therefore, it occurs when the curved portion approaches the abdominal surface (1a). In addition, since the main reinforcement (2) of the ALC panel is linearly processed in the purchase state or by pre-processing, the abnormality appearing in the main reinforcement does not appear as a local sharp curved shape.

  For example, if the ALC panel (1) shown in FIG. 2 has an abnormality as shown in FIG. 3 (a), the ALC panel is measured under conditions of a sensor speed of 100 mm / s and a distance between the sensor and the abdominal surface (L) of 5 mm. Then, the peak value is 4.18V as a whole, and the cover thickness t obtained from all the peak values is 5 mm, which is below the predetermined value of 7.5 mm.

  3B, when measured under the same conditions, the peak value measured initially is 3.96 V and the cover thickness t is 2.5 mm, but the cover thickness is moderate. The peak value measured at the end is 4.55 V, the cover thickness t is 15 mm, and exceeds the predetermined value of 7.5 mm.

  Further, when there is an abnormality as shown in FIG. 3 (c), when measured under the same conditions, the measured peak value is 4.43V as a whole, and the cover thickness t is 10 mm. In a plurality of peaks in the part, the cover thickness tends to gradually decrease, and then the cover thickness gradually returns. And in a part of peak which shows this tendency, a peak value will be 3.96V, and the cover thickness t will be 2.5 mm and will be less than 7.5 mm which is predetermined value.

  The ALC panel (1) is provided with a plurality of main bars (2), and only some of them may be abnormal. However, in the case of four main bars, for example, the peaks appear in the order ABCDDCBA..., And thus the above-described tendency appears for the peak for a specific main bar.

  Therefore, basically, even if one of the measured peaks is less than the predetermined value, it can be detected as a cover thickness abnormality.

  According to the present invention, in principle, by connecting a simple eddy current type magnetic sensor to a simple motion mechanism without using a dedicated device, the moving speed of the sensor can be used as a parameter, and the peak value of the output can be obtained. The cover thickness can be easily measured, and thereby it is possible to eliminate an ALC panel with an abnormal cover thickness from the production line.

  However, when the eddy current type magnetic sensor (7) is brought close to the abdominal surface (1), in the portion (5) intersecting with the reinforcing reinforcing bar (3), the derivative overlaps, so the cover thickness is normal. However (even if the actual distance is normal), since the induced current becomes large, it is overdetected to determine that the cover thickness is less than the predetermined value (the distance between the abdominal surface and the main muscle is close). I will regard it.

  In particular, when measuring while moving the ALC panel, it becomes difficult to determine whether the output value of the eddy current type magnetic sensor (7) is due to an abnormality in the reinforcing bar cover thickness or due to the intersection of reinforcing bars. .

  Excluding them is not preferable from the viewpoint of production efficiency, and therefore it is necessary to reconfirm each time for ALC panels that are determined to be normal but have an abnormal cover thickness. However, this work greatly affects the productivity of ALC panels.

  Therefore, in the present invention, peak cut processing or movement is performed on a plurality of continuous peak values for each main bar (2) extending in the transport direction in one ALC panel (1) obtained from the analog output. By performing the averaging process, the influence of the excessive peak value caused by the reinforcing reinforcing bars (3) intersecting with the main reinforcing bars (2) is removed.

  Specifically, a plurality of peak values are obtained from each main muscle (in FIG. 2) based on information such as the time elapsed from the reciprocal base point of the eddy current magnetic sensor (7), the position data held by the motion mechanism, and the order of peak values. For each of the four), a continuous peak value can be obtained.

  As described above, the main muscle (2) does not bend and a cover thickness abnormality does not occur. Therefore, the cover thickness abnormality does not project a part of the continuous peak, and gradually changes from the normal value to an abnormal value.

  Therefore, for each main bar, if only one or two of the continuous peak values show an output value that protrudes due to the influence of the intersection with the reinforcing bar, the peak value is eliminated by performing peak cut processing. Then, the cover thickness is calculated from the remaining peak value, and when no abnormality is recognized, it is determined as normal.

  Alternatively, the moving average process is performed for all peak values, the cover thickness is calculated from the peak value of the moving average, and if no abnormality is found in them, it is determined as normal. Thereby, it becomes possible to eliminate the influence by the intersection with the auxiliary reinforcing bars, and it is possible to prevent the overdetection as described above.

  Note that the peak cut process is a technique that excludes a predetermined number of maximum and minimum values, and the moving average process is a technique that calculates the average of a plurality of consecutive measurement values. Is also an arithmetic method known in statistics.

  Furthermore, by using two or more eddy current type magnetic sensors perpendicular to the transport direction for one ALC panel as shown in FIG. 5, the main bars parallel to the transport direction are divided into two or more. To measure. As described above, when the main muscle is divided into two or more and measured, the same effect can be obtained even when transported at a higher speed.

  The eddy current type magnetic sensor is moved to the end of the ALC panel at a constant speed, decelerated, reversed in the moving direction, accelerated to a predetermined speed, and then from end to end of the ALC panel, or end It is necessary to move at a uniform speed from at least to the intermediate portion in the width direction, at least in the main muscle information.

  Thus, in the present invention, since the influence due to the intersection with the reinforcing reinforcing bars can be excluded, the cover thickness closest to the abdominal surface exceeds a predetermined value in the cover thickness distribution of the main bars obtained by the above measurement method. In this case, it is possible to determine that the main bar cover thickness is abnormal.

It is sectional drawing which shows the state which performs the main bar cover thickness measuring method of the ALC panel of this invention. It is a partially broken perspective view which shows an ALC panel. It is sectional drawing which shows the ALC panel of FIG. It is a figure which shows the locus | trajectory which an eddy current type magnetic sensor moves with respect to an ALC panel. It is a figure which shows the locus | trajectory which an eddy current type magnetic sensor moves with respect to an ALC panel. It is a graph which shows the sensor output with respect to movement speed, when passing a main muscle. It is a graph which shows the relationship of the peak of the detected value with respect to the space | interval of an eddy current type magnetic sensor and a main muscle, using a moving speed as a parameter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ALC panel 1a Abdominal surface 2 Main reinforcement 3, 4 Reinforcement reinforcement 5 Overlap part 6a, 6b, 6c Cover thickness 7 Eddy current type magnetic sensor L Distance between ALC panel and eddy current type magnetic sensor t Cover thickness f Main reinforcement and eddy current Distance to the magnetic sensor vm Detected value of the measurement signal v0 ALC panel transport speed v1 Moving speed of the eddy current magnetic sensor

Claims (3)

A method for measuring a cover thickness from the abdominal surface of an ALC panel that is conveyed in a straight line in a horizontal direction to a main muscle, using an eddy current type magnetic sensor using an excitation coil and a detection coil, the eddy current type magnetic sensor Is reciprocated in a direction perpendicular to the transport direction of the ALC panel at a constant speed (v1) while maintaining a constant distance (L) from the abdominal surface of the ALC panel. Are output in analog, and the peak value (vm) of the measurement signal when the eddy current type magnetic sensor passes over the main muscle, the velocity (v1), the eddy current type magnetic sensor and the main muscle. relationship f (peak value, speed) of the distance between the obtained in advance, the head thickness of the main reinforcement and (t), t = f ( vm, v1) is calculated by -L, main reinforcement cover thickness measuring method of ALC panel Because
Crossing the main bars by performing peak cut processing or moving average processing on a plurality of continuous peak values for each main bar extending in the transport direction in one ALC panel obtained from the analog output A main bar cover thickness measurement method for ALC panels , which eliminates the influence of excessive peak values caused by reinforcing reinforcing bars .   Two or more eddy current type magnetic sensors are provided in a direction perpendicular to the transport direction of the ALC panel, and the width of the ALC panel is reduced by the two or more eddy current type magnetic sensors with respect to one ALC panel. The main bar cover thickness measuring method for an ALC panel according to claim 1, wherein the measurement is performed by dividing in a direction. In the distribution of the main muscle cover thickness obtained by the ALC main muscle cover thickness measurement method according to claim 1 or 2, when the cover thickness closest to the abdominal surface exceeds a predetermined value, an abnormality in the main muscle cover thickness A main panel cover thickness abnormality determination method of ALC panel.

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