JP6404043B2 - Speedometer - Google Patents

Description

  The present invention relates to a speedometer, and is particularly suitable for use in measuring the moving speed of an object to be measured.

Conventionally, the surface of an object to be measured is irradiated with a laser beam to receive the reflected light, and the Doppler effect in which the frequency of the received reflected light changes according to the moving speed of the object to be measured is used. Measuring the moving speed has been done.
As a technique related to such a laser Doppler type speed detector, there is a technique described in Patent Document 1. In the technique described in Patent Document 1, a speed detector that detects the speed using the Doppler effect is housed in the housing, and measured from the speed detector through the inside of a hollow purge nozzle provided at the end of the housing. The surface of the object is irradiated with laser light. Further, in the technique described in Patent Document 1, the purge nozzle is a tapered nozzle, a side purge nozzle is provided outside the tapered purge nozzle, and the side purge nozzle is disposed outside the purge air region ejected from the purge nozzle. Purge air is blown out.

JP 2006-326647 A

  The present applicants used a speedometer to which the technique described in Patent Document 1 was applied in order to measure the cutting length of a slab such as a slab in a continuous casting facility. As a result, when the moving speed of a material to be measured, such as a continuous casting material in a continuous casting machine, is measured with such a speedometer, the measured speed varies and does not show a stable value. I knew I couldn't do it.

  Therefore, an object of the present invention is to enable accurate measurement of the moving speed even when the moving speed of the object to be measured is slow.

The speedometer of the present invention has at least one of the following configurations (1) to ( 3 ).
(1) A protective case and a laser beam irradiated to the surface of the object to be measured that is fixed and moving inside the protective case to receive the reflected light and use the Doppler effect based on the received reflected light A speed detector for measuring the moving speed of the object to be measured, and a hollow nozzle from the protective case so that the optical path of the laser light and the reflected light of the laser light is positioned in the hollow portion. Also, a purge nozzle that is disposed on the measured object side with a gap from the protective case, injects gas from the tip of the nozzle to the surface of the measured object, and a hollow attached to the lower surface of the protective case. A shielding material, and an upper end portion of the shielding material faces a lower surface of the protective case so that an inner circumferential surface of the shielding material faces the outer circumferential surface on the proximal end side of the purge nozzle with a gap therebetween. Attached to the front The gas supplied from the supply port formed on the side surface of the purge nozzle to the inside of the purge nozzle forms a gas flow from the inside of the purge nozzle toward the gap between the protective case and the purge nozzle, and the protective case A speedometer that prevents foreign matter from entering the purge nozzle through a gap between the protective case and the purge nozzle in a state where the protective case and the purge nozzle are separated .
(2) A nozzle provided on the outer peripheral surface on the front end side of the purge nozzle, in at least a part of the area around the injection region of the gas injected from the front end of the purge nozzle to the surface of the object to be measured A side purge nozzle for injecting gas is further provided, and the purge nozzle is a tapered nozzle having a tip portion whose inner diameter is tapered, and is a supply port formed on a side surface of the purge nozzle, into the purge nozzle. The speedometer according to (1), wherein a supply port for supplying the gas is formed on a side surface closer to the base end side than the tip end portion of the purge nozzle.
( 3 ) The speedometer according to (1) or (2) , wherein the protective case and the speed detector are attached to a frame via a member that suppresses vibration.

According to the present invention, it is possible to accurately measure the moving speed even when the moving speed of the object to be measured is slow.

It is sectional drawing which shows an example of a structure of a continuous casting machine. It is a figure which shows the 1st example of schematic structure of a speedometer. It is a figure which shows an example of the surface pressure distribution by purge air. It is a figure which shows an example of the area | region where side purge air is ejected. It is a figure which shows an example of the surface pressure distribution by purge air. It is a figure which shows an example of the surface pressure distribution by purge air and side purge air. It is a figure which shows the 2nd example of schematic structure of a speedometer.

Before describing the embodiments of the present invention, the knowledge obtained by the present inventor before reaching the embodiments of the present invention will be described.
As described above, as a result of measuring the moving speed of the continuous cast material in the continuous casting machine using the speedometer to which the technique described in Patent Document 1 is applied, the speed measured by the speedometer varies and accurate measurement is performed. Could not do.

  As a cause of this, first, the Doppler frequency obtained by the laser Doppler type speed detector is proportional to the moving speed of the object to be measured. The moving speed of the continuous casting material in the continuous casting machine is about 0.1 mpm to 3 mpm, which is a low speed. When such a low moving speed is measured by a laser Doppler type speed detector, the ratio of the noise component included in the signal component increases. This is because laser Doppler type speed detectors are not suitable for such low speed measurement, and until now, laser Doppler type speed detectors have not been used for measuring the moving speed of continuous casting materials. Agree.

Moreover, in the technique described in Patent Document 1, a housing in which a speed detector is accommodated and a purge nozzle are combined. Therefore, the vibration of the purge nozzle when the purge air is ejected is transmitted to the speed detector. Due to the vibration of the speed detector, the speed measured by the speed detector also varies.
Based on the knowledge found by the present inventors as described above, the inventors have arrived at an embodiment of the present invention described below. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
First, a first embodiment of the present invention will be described. In the present embodiment, the case where the moving speed of a continuous cast material in a continuous casting facility is measured and the cutting length of a cast piece such as a slab is determined from the measured moving speed will be described as an example.
FIG. 1 is a cross-sectional view showing an example of the configuration of a continuous casting machine.
In FIG. 1, the refined molten steel 10 is put into a ladle 11 and conveyed, and placed on a rotary table 12. The molten steel 10 in the ladle 11 is continuously poured into the mold 14 by the immersion nozzle 19 via the tundish 13. The molten steel 10 poured into the mold 14 is cooled and solidified by the spray nozzle 16, and is slowly and continuously pulled down below the mold 14 while being supported by the support roll 15. The solidified molten steel 10 is cut into a predetermined length by a cutting machine 17 to become a steel piece 18 called a slab, billet, or bloom. In the following description, the solidified molten steel is referred to as “continuous cast material” as necessary.

  The speedometer 100 is for measuring the moving speed of the continuous cast material, and is disposed above the continuous cast material at a position immediately before the cutting machine 17. When it is determined that the length of the continuous casting material that has passed through the cutting machine 17 has reached a predetermined length based on the moving speed and elapsed time of the continuous casting material measured by the speedometer 100, the cutting machine 17. The continuous casting is cut. In addition, in FIG. 1, the case where the speedometer 100 was arrange | positioned above the continuous casting material was mentioned as an example, and it showed. However, the speedometer 100 can be disposed below the continuous cast material, or the speedometer 100 can be disposed both above and below the continuous cast material. Further, the speedometer 100 can be arranged at a position immediately after the cutting machine 17.

FIG. 2 is a diagram illustrating an example of a schematic configuration of the speedometer 100 of the present embodiment. In FIG. 2, the outline of the longitudinal cross-section of the speedometer 100 is shown.
In FIG. 2, the speedometer 100 includes a protective case 101, a speed detector 102, a purge nozzle 103, a side purge nozzle 104, and purge air supply pipes 105 and 106.

The protective case 101 is for accommodating and protecting the speed detector 102. The protective case 101 is provided with a water cooling pipe (not shown), for example, and the speed detector 102 can be cooled by flowing cooling water through the water cooling pipe.
As described above, the speed detector 102 is accommodated in the protective case 101. Specifically, the speed detector 102 is attached and fixed to the protective case 101 directly or via a member inside the protective case 101. Therefore, when the protective case 101 vibrates, the speed detector 102 also vibrates.

The speed detector 102 is a laser Doppler type speed detector. In the laser Doppler type speed detector, the surface of the continuous casting material C is irradiated with two laser beams at a predetermined incident angle from the front side and the rear side with respect to the traveling direction of the continuous casting material C that moves. The reflected light is received by the same light receiver. Based on these shift amounts, the continuous cast material C is utilized by utilizing the fact that one laser beam is shifted to the higher frequency side due to the Doppler effect and the other laser beam is shifted to the lower frequency side due to the Doppler effect. Find the moving speed of.
Since the laser Doppler type speed detector can be realized by a known technique, a detailed description thereof is omitted here.
In addition, at least a region serving as an optical path of the laser light irradiated by the speed detector 102 and the reflected light of the laser light received by the speed detector 102 in the lower surface region of the protective case 100 is open.

  The purge nozzle 103 is a hollow nozzle that extends in the vertical direction below the protective case 101. The purge nozzle 103 is arranged so that the tip thereof faces the surface of the continuous cast material C with a gap and the base end face of the purge nozzle 103 faces the protective case 101 with a gap. That is, the purge nozzle 103 of the present embodiment is disposed below the protective case 101 and separated from the protective case 101 with a gap.

  The purge nozzle 103 has a base end portion 103a having a constant inner diameter, an intermediate portion 103b having a tapered inner diameter (the inner diameter becomes smaller as the position of the tip is closer), and a distal end portion 103c having a constant inner diameter. . The base end portion 103a and the intermediate portion 103b are connected to each other, and the inner diameter of the connecting portion is the same. Moreover, the intermediate part 103b and the front-end | tip part 103c are mutually connected, and the internal diameter in a connection part is the same. Accordingly, the inner diameter of the distal end portion 103c is smaller than the inner diameter of the proximal end portion 103a. Thus, the intermediate portion 103b of the purge nozzle 103 has the tapered portion 103d and has a tapered shape.

  In addition, the protective case 101, the speed detector 102, and the optical path of the laser light irradiated by the speed detector 102 and the reflected light of the laser light received by the speed detector 102 are not in contact with the inner wall of the purge nozzle 103. The positional relationship of the purge nozzle 103 is determined. It is preferable that the vertical direction passing through the point where the two laser beams irradiated from the speed detector 102 intersect (the target position of the two laser beams) substantially coincides with the axial direction of the purge nozzle 103.

  A supply port is formed on the side surface of the base end portion of the purge nozzle 103, and a purge air supply pipe 105 is attached to the supply port. The purge air supply pipe 105 is for introducing high-pressure air from a high-pressure air supply device (not shown) such as a gas cylinder into the hollow portion (inside) of the purge nozzle 103 and is supplied to the hollow portion (inside) of the purge nozzle 103. The flow of high-pressure air is configured to be downward. In the present embodiment, the supply port of the purge air supply pipe 105 is directed obliquely downward so that the flow of high-pressure air supplied to the hollow portion (inside) of the purge nozzle 103 is downward. In this way, by inclining the purge air supply pipe 105, the flow direction of the high-pressure air can be lowered. This high-pressure air is ejected from the tip of the purge nozzle 103 toward the surface of the continuous casting material C. With this high-pressure air, heated air from the continuous cast material C can be excluded from the optical path of the laser beam. Thereby, the fluctuation | variation of the refractive index of the medium in the optical path of a laser beam can be suppressed. As described above, the speedometer 100 according to the present embodiment can measure the moving speed of the measurement object having a high surface temperature. For example, it is preferable to use the speedometer 100 of the present embodiment in order to measure the moving speed of the measurement object having a surface temperature of 600 ° C. or higher.

In the present embodiment, the region I of the gap between the purge nozzle 103 and the protective case 101 is not shielded (a configuration in which the flow of air from the region I of the gap between the purge nozzle 103 and the protective case 101 to the inside of the purge nozzle 103 is suppressed. (Not provided). As a result, the air around the purge nozzle 103 is drawn into the purge nozzle 103 from the region I of the gap between the purge nozzle 103 and the protective case 101. That is, the gap between the purge nozzle 103 and the protective case 101 is inserted into the hollow portion (inside) of the purge nozzle 103 by being dragged by the downward flow of high-pressure air supplied from the purge air supply pipe 105 to the hollow portion (inside) of the purge nozzle 103. A downward air flow is generated from the region I. Thereby, even if the supply amount of the purge air introduced from the purge air supply pipe 105 is reduced, the purge air having a desired flow rate can be obtained.
Further, the purge air injection speed can be set according to the distance from the tip of the purge nozzle 103 to the continuous casting material C because the purge effect becomes higher when the distance from the tip of the purge nozzle 103 to the continuous casting material C is as close as possible. In the embodiment, it is preferable to set the pressure at about 30 m / s at a position 100 mm from the tip of the purge nozzle 103.

As described above, in the present embodiment, the purge nozzle 103 is disposed in a state of being physically separated from the protective case 101 with a space below the protective case 101.
Therefore, vibration generated in the purge nozzle 103 when the purge air is ejected from the purge nozzle 103 onto the surface of the continuous cast material C as described above can be prevented from being transmitted to the protective case 101 (speed detector 102). Therefore, in the speedometer 100 of the present embodiment, a measurement object having a low moving speed can be set as a measurement target. For example, it is preferable to use the speedometer 100 of the present embodiment in order to measure the moving speed of an object to be measured having a moving speed of 0.1 mpm to 3.0 mpm.

  In the present embodiment, since the foundation bases (structures) 107 and 108 that support the purge nozzle 103 and the protective case 101 are individually provided, it is possible to reliably suppress the vibration of the purge nozzle 103 from being transmitted to the speedometer 100. can do. However, the foundation bases (structures) 107 and 108 that support the purge nozzle 103 and the protective case 101 are not necessarily provided individually. For example, a common base frame (structure) that supports the purge nozzle 103 and the protective case 101 is used in common, and vibrations of the purge nozzle 103 are prevented from being transmitted to the speedometer 100 by using members such as vibration-proof rubbers 109 to 111. You may make it do.

  Further, in this embodiment, the tapered purge nozzle 103 is used, and a very narrow area around the laser light irradiation surface, for example, a point where two laser lights irradiated from the speed detector 102 intersect (the aim of the two laser lights). The purge air is concentrated in a narrow region within a circle having a radius of about 10 mm to 15 mm centering on the position). For example, the tip diameter of the tapered purge nozzle 103 is 27 mm, and the purge air is concentrated in a 27 mm diameter region. As a result, it is possible to greatly reduce the flow rate of the purge air required to ensure the surface pressure for removing the heated air from the continuous cast material C, and to reduce the noise level.

  Note that two laser beams of the continuous casting material C are irradiated from the front side and the rear side with respect to the traveling direction of the continuous casting material C, and a predetermined distance from the tip of the purge nozzle 103 (for example, continuous casting from the tip of the purge nozzle 103). When the assumed value of the distance to the surface of the material C is 1 m, the two laser beams are crossed at 1 m). Therefore, the inner diameter of the purge nozzle 103 from the base end side to the tip end side cannot be shortened.

  By the way, when a purge nozzle 103 having a tapered tip is used, as shown in FIG. 3, a predetermined surface pressure is applied to a region in the vicinity of the surface of the continuous cast material C that intersects the axis of the purge nozzle 103. Although it can be ensured, the surface pressure near the region directly below the outer peripheral surface of the base end portion of the purge nozzle 103 tends to rapidly decrease. Therefore, depending on the measurement environment (cooling water or scale scattering amount or scattering speed, water on the measurement surface of the continuous cast material, steam amount, etc.), the axis of the purge nozzle 103 in the region of the surface of the continuous cast material C There is a possibility that a gas or the like that hinders measurement by the speed detector 102 may enter a region near the intersection (on the optical path of the laser beam). In this case, there is a possibility that stable measurement cannot be performed only with the purge nozzle 103. Therefore, in this embodiment, in order to suppress such intrusion of gas or the like by securing the surface pressure in the outer peripheral region where the desired surface pressure cannot be secured by the purge nozzle 103, in this embodiment, the tip of the purge nozzle 103 is used. A side purge nozzle 104 is provided outside the section. In the following description, “a region in the vicinity of the surface of the continuous cast material C that intersects the axis of the purge nozzle 103” will be referred to as a “central region” as necessary.

  The side purge nozzle 104 is purge air at a position outside the central region (for example, a region within a circle having a radius of 30 mm to 50 mm centered on a point intersecting the axis of the purge nozzle 103 in the surface region of the continuous cast material C). The surface pressure due to the above is ensured, and the heated air from the continuous casting material C is surely excluded from the optical path of the laser beam. A supply port is formed above the side purge nozzle 104, and a purge air supply pipe 106 is attached to the supply port. The purge air supply pipe 106 is for introducing high-pressure air from a high-pressure air supply device (not shown) such as a gas cylinder into the hollow portion (inside) of the side purge nozzle 104, and the hollow portion (inside) of the side purge nozzle 104. The flow of the high-pressure air supplied to is arranged downward. The high-pressure air is ejected from the tip of the purge nozzle 104 toward the surface of the continuous casting material C. In the following description, the purge air ejected from the side purge nozzle 104 is referred to as side purge air as necessary.

  FIG. 4 is a diagram illustrating an example of a region where side purge air is ejected by the side purge nozzle 104. As shown in FIG. 4A, the side purge nozzle 104 is configured so that the side purge air is supplied to at least two regions 402a and 402b in the traveling direction of the continuous cast material C at least across the central region 401. can do. Further, as shown in FIG. 4B, the side purge nozzle 104 can be configured so that the side purge air is supplied to a circumferential region 403 around the central region 401. In the present embodiment, a large number of pores are linearly formed on both the front and rear sides of the side purge nozzle 104 so that the side purge air is supplied to the regions 402a and 402b shown in FIG.

  FIG. 5 is a diagram illustrating an example of a surface pressure distribution by the purge air and the side purge air. As shown in FIG. 5, the surface pressure by the side purge air is 80% of the surface pressure at the center (the point intersecting the axis of the purge nozzle 103 in the surface area of the continuous cast material C) formed by the tapered purge nozzle 103. It is preferable to be at the above level. Further, in order to obtain a high side purge air surface pressure while suppressing the amount of purge air jetted, the jet angle from the side purge nozzle 103 is set to 45 ° with respect to the normal of the surface (plate surface) of the continuous cast material C. The following is preferable. In the present embodiment, this ejection angle is set to 30 °. If this ejection angle exceeds 45 °, the ejection amount of the side purge air necessary for ensuring the surface pressure of the side purge air on the surface of the continuous cast material C increases, and the noise reduction effect decreases. As shown in FIG. 5, if the surface pressure peak is doubled in the traveling direction, the heated air from the continuous cast material C can be surely excluded.

FIG. 6A and FIG. 6B are diagrams illustrating an example of an effect obtained by providing a gap between the protective case 101 and the purge nozzle 103.
Here, in order to verify the effect obtained by providing a gap between the protective case 101 and the purge nozzle 103, the side purge nozzle 104 is not provided, but only the purge nozzle 103 is provided to configure the speedometer.
FIG. 6A shows the continuous cast material C in the case of using a speedometer configured such that a distance of 70 mm is provided between the protective case 101 and the purge nozzle 103 as in this embodiment, and these are separated. It is a figure which shows the measurement result of a moving speed. FIG. 6B is a diagram showing the measurement result of the moving speed of the continuous cast material C when using a speedometer configured such that the protective case and the purge nozzle are coupled as in Patent Document 1. The speedometer with a gap between the protective case and the purge nozzle is provided with a gap between the protective case and the purge nozzle, and only the point where the overall length of the purge nozzle is shortened by the distance is provided between the protective case and the purge nozzle. It is different from the speedometer which combined.

The moving speed of the continuous cast material C and the supply conditions of the purge air are the same in any speedometer. More specifically, the moving speed of the continuous cast material C is about 1 mpm. Further, the flow rate of purge air on the surface of the continuous cast material C was about 1 Nm ³ / min, and the speed of purge air on the surface of the continuous cast material C was about 15 m / s. In any speedometer, the sampling period was 2 ms.

As shown in FIGS. 6 (a) and 6 (b), a clearance is provided between the protective case 101 and the purge nozzle 103, and by separating them, the measurement result of the moving speed of the continuous cast material C is highly accurate. It can be seen that it can be obtained stably and stably.
On the other hand, when the result shown in FIGS. 6A and 6B is integrated and converted into a length, when the protective case and the purge nozzle are combined, the length error of the continuous cast material C is 1 It was found that an error of 1 mm to 3 mm occurred per minute. Since the moving speed of the continuous casting material C is 1 mpm, 0.1% to 0.3% becomes an error due to the vibration of the purge nozzle being transmitted to the protective case (speed detector) and the speed detector vibrating. As described above, when the moving speed of the object to be measured is low, an error in speed that does not become apparent when the moving speed of the object to be measured is high becomes apparent.

  As described above, in this embodiment, the purge nozzle 103 is disposed below the protective case 101 that houses the speed detector 102 so as to be spaced from the protective case 101. The high-pressure air supplied from the purge air supply pipe 105 is introduced into the purge nozzle 103 from the base end portion of the purge nozzle 103 to create a flow of purge air toward the tip of the purge nozzle 103. By doing so, the vibration generated in the purge nozzle 103 when the purge nozzle 103 ejects the purge air and the vibration generated in the side purge nozzle 104 when the side purge nozzle 104 ejects the side purge air are caused by the protective case 101 ( Transmission to the speed detector 102) can be reliably prevented. Therefore, even when measuring the moving speed of an object having a low moving speed, such as the continuous cast material C, it is possible to suppress a decrease in speed detection accuracy in the speed detector 102. In addition, air flowing toward the tip of the purge nozzle 103 is formed inside the purge nozzle 103 from the gap between the purge nozzle 103 and the protective case 101. This air is also ejected from the purge nozzle 103 as part of the purge air. Therefore, even if the supply amount of high-pressure air from the purge air supply pipe 105 is reduced, purge air with a desired flow rate can be obtained.

In this embodiment, the case where air (air) is ejected from the purge nozzle 103 and the side purge nozzle 104 has been described as an example. However, the gas supplied from the purge nozzle 103 and the side purge nozzle 104 is not limited to air. For example, an inert gas such as nitrogen gas may be used.
Further, if the purge nozzle 103 is tapered by providing the tapered portion 103a and the side purge nozzle 104 is used, the heated air from the continuous casting material C can be surely excluded from the optical path of the laser beam. Therefore, it is not always necessary to do this.
Further, if the side purge nozzle 104 is used as in the present embodiment, it is possible to reliably suppress the entry of gas or the like that hinders measurement by the speed detector 102 into the central region even in a situation where the measurement environment is bad. preferable. However, when the measurement environment is good or the like, the side purge nozzle 104 is necessarily used when the purge nozzle 103 alone can suppress the entry of gas or the like that hinders measurement by the speed detector 102 into the central region. There is no.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. With the speedometer 100 described in the first embodiment, high-precision measurement is possible even when the moving speed of the object to be measured is low (about 0.1 mpm to 3 mpm). However, the application target of the speedometer 100 is not limited to such a movement speed (even if the movement speed exceeds 3 mpm, it is an application target). Therefore, in this embodiment, a case where the moving speed of the steel plate in the hot rolling line is measured will be described as an example.

  However, when measuring the moving speed of the steel sheet in the hot rolling line, foreign matters such as coolant and steam are generated around the speedometer. When the protective case 101 and the purge nozzle 103 are spaced apart from each other as in the first embodiment, the measurement by the speed detector 102 is performed inside the protective case 101 and the purge nozzle 103 from the gap between the protective case 101 and the purge nozzle 103. There is a risk that liquid or gas (coolant liquid, vapor, etc.) that hinders the penetration. Therefore, in the present embodiment, while ensuring that the protective case 101 and the purge nozzle 103 are separated, a liquid or a gas (a coolant liquid or a coolant) that hinders measurement by the speed detector 102 is provided inside the protective case 101 or the purge nozzle 103. (Steam, etc.) is prevented from entering. As described above, the speedometer of the present embodiment has a configuration for preventing the coolant liquid, steam, and the like from entering the protective case 101 and the purge nozzle 103 in the speedometer 100 of the first embodiment. Is. Therefore, in the description of the present embodiment, the same portions as those in the first embodiment are denoted by the same reference numerals as those in FIGS.

FIG. 7 is a diagram illustrating an example of a schematic configuration of the speedometer 700 of the present embodiment. FIG. 7 is a diagram corresponding to FIG.
In FIG. 7, the speedometer 700 includes a protective case 101, a speed detector 102, a purge nozzle 103, a side purge nozzle 104, purge air supply pipes 702 a, 702 b and 106, and a shielding cylinder 701.

  The upper end of the hollow shielding cylinder 701 is connected to the lower surface of the protective case 101 so that the inner peripheral surface thereof is opposed to the region of the outer peripheral surface on the proximal end side of the purge nozzle 103 with a gap therebetween. ing. At this time, it is preferable that the axis of the shielding cylinder 701 and the axis of the purge nozzle 103 substantially coincide with each other. As described in the first embodiment, the vertical direction passing through the point where the two laser beams emitted from the speed detector 102 intersect (the target position of the two laser beams) is the axis of the purge nozzle 103. It is preferable to substantially match the direction.

  A supply port is formed in the side surface of the base end portion of the purge nozzle 103, and a purge air supply pipe 702 is attached to the supply port. The purge air supply pipes 702a and 702b are for introducing high-pressure air from a high-pressure air supply device (not shown) such as a gas cylinder into the hollow portion (inside) of the purge nozzle 103, and are supplied to the hollow portion (inside) of the purge nozzle 103. The flow of the high-pressure air to be generated is generated in the upper and lower directions. In the present embodiment, the supply port of the purge air supply pipe 702a faces obliquely below the purge nozzle 103 so that the flow of high-pressure air supplied to the hollow portion (inside) of the purge nozzle 103 is generated in the upward and downward directions. In addition, the supply port of the purge air supply pipe 702b faces obliquely upward. In this way, by inclining the purge air supply pipes 702a and 702b, it is possible to form a flow of high-pressure air directed upward and downward. Among such high-pressure air, high-pressure air traveling downward is ejected from the tip of the purge nozzle 103 toward the surface of the steel sheet S. On the other hand, the high-pressure air traveling upward is supplied to a region I in the gap between the purge nozzle 103 and the protective case 101. The flow of high-pressure air directed upward may be such that air is not sucked into the purge nozzle 103 from the region I of the gap between the purge nozzle 103 and the protective case 101.

In this way, the downward air flow is not formed from the region I of the gap between the purge nozzle 103 and the protective case 101 as in the first embodiment. Therefore, in order to make the flow rate of the purge air ejected from the purge nozzle 103 the same as that in the first embodiment, the supply amount of the high-pressure air supplied from the purge air supply pipe 702a may be increased.
Further, in the present embodiment, since it is only necessary to suppress the vibration generated in the purge nozzle 103 when the purge air is jetted onto the surface of the continuous cast material C, it can be suppressed from being transmitted to the protective case 101 (speed detector 102). The case 101 may not be in contact (if it is physically separated).
Moreover, in this embodiment, since the moving speed of the steel plate in a hot rolling line is measured, a lot of coolant liquid exists around the speedometer 700. Also in the present embodiment, as in the first embodiment, the side purge nozzle 104 is provided outside the front end portion of the purge nozzle 103, and therefore, such a region in the vicinity where the coolant liquid intersects the axis of the purge nozzle 103 ( It is possible to suppress entry into the laser light path).

  Further, similarly to the first embodiment, in this embodiment, the foundation frames (structures) 703 and 704 that support the purge nozzle 103 and the protective case 101 are individually provided, and each foundation frame 703 is provided. , 704 are physically separated from other structures (equipment). The purge nozzle 703 is attached to the foundation frame 703 via a vibration isolating rubber 705, and the protective case 101 is attached to the foundation frame 704 via vibration isolating rubbers 706 and 707.

  As described above, in the present embodiment, the upper end portion of the shielding cylinder 701 is opposed to the lower surface of the protective case 101 so that the inner circumferential surface of the shielding cylinder 701 and the outer circumferential surface on the proximal end side of the purge nozzle 103 are opposed to each other with a gap. Attach to. Further, an air flow is formed from below toward the region I of the gap between the purge nozzle 103 and the protective case 101. By doing in this way, it can suppress that coolant liquid, a vapor | steam, etc. enter into the inside of the protective case 101 or the purge nozzle 103, ensuring the clearance gap between the protective case 101 and the purge nozzle 103. FIG.

Note that only one of providing the shielding cylinder 701 and forming the air flow in the direction of the region I of the gap between the purge nozzle 103 and the protective case 101 may be performed.
In the present embodiment, the flow of high-pressure air supplied to the hollow portion (inside) of the purge nozzle 103 is generated in the upper and lower directions by one purge air supply pipe 702a, 702b. However, two purge air supply pipes are attached to the side surface of the base end portion of the purge nozzle, and the upward flow is formed by the high pressure air from one of the two purge air supply pipes, and the other purge air supply pipe A downward flow may be formed by the high pressure air from.
Also in the present embodiment, the modification described in the first embodiment can be employed.

  It should be noted that the embodiments of the present invention described above are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed as being limited thereto. Is. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

  100, 700; speedometer, 101; protective case, 102; speed detector, 103; purge nozzle, 104; side purge nozzle, 105, 106, 702a, 702b; purge air supply pipe, 107, 108, 703, 704; 109, 110, 111, 705, 706, 707; anti-vibration rubber, 701; shielding cylinder

Claims (3)

A protective case,
The surface of the object to be measured that is fixed inside the protective case is irradiated with a laser beam to receive the reflected light, and the Doppler effect is used based on the received reflected light of the object to be measured. A speed detector for measuring the moving speed;
A hollow nozzle having a gap with the protective case on the measured object side of the protective case so that the optical path of the laser light and the reflected light of the laser light is located in the hollow portion A purge nozzle that is disposed and injects gas from the tip of the nozzle onto the surface of the object to be measured;
A hollow shielding material attached to the lower surface of the protective case ,
The upper end portion of the shielding material is attached to the lower surface of the protective case so that the inner circumferential surface of the shielding material is opposed to the outer circumferential surface on the base end side of the purge nozzle with a gap therebetween.
The gas supplied from the supply port formed in the side surface of the purge nozzle to the inside of the purge nozzle forms a gas flow from the inside of the purge nozzle toward the gap between the protective case and the purge nozzle, and the protection A speedometer characterized by suppressing foreign matter from entering the inside of the purge nozzle through a gap between the case and the purge nozzle in a state where the protective case and the purge nozzle are separated . A nozzle provided on the outer peripheral surface on the front end side of the purge nozzle, injecting gas into at least a part of the area around the injection area of the gas to be ejected from the front end of the purge nozzle to the surface of the object to be measured A side purge nozzle that further
The purge nozzle is a tapered nozzle having a tip portion with a tapered inner diameter,
A supply port formed on a side surface of the purge nozzle, the supply port for supplying gas to the inside of the purge nozzle being formed on a side surface closer to the base end side than the distal end portion of the purge nozzle. The speedometer according to claim 1. The protective case and the speed detector, the speed meter according to claim 1 or 2, characterized in that attached to the frame via the suppressing member vibration.

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