KR101649670B1 - Apparatus for measuring thickness and method for measuring the same - Google Patents

Abstract

The present invention relates to a thickness measuring apparatus and a thickness measuring method, and more particularly to an apparatus and a method for measuring the thickness of molten mold flux on a molten steel taken in a mold. An embodiment of the present invention is a thickness measuring apparatus for measuring a thickness of an intermediate layer in a fluid material composed of a lower layer, an intermediate layer and an upper layer accommodated in a container, the thickness measuring apparatus comprising: a light source for irradiating laser light onto a surface of the fluid, A laser distance measuring unit for calculating a distance to the surface of the fluid using the laser light and the reflected light; A thickness calculating unit for calculating a thickness of the intermediate layer using a distance to the surface of the fluid; And a light guiding unit guiding the laser light emitted from the laser distance measuring unit to the surface of the fluid and guiding the reflected light reflected from the surface of the fluid to the laser distance measuring unit.

Description

TECHNICAL FIELD The present invention relates to an apparatus for measuring thickness,

The present invention relates to a thickness measuring apparatus and a thickness measuring method, and more particularly to an apparatus and a method for measuring the thickness of molten mold flux on a molten steel taken in a mold.

The control of the thickness of the molten mold flux injected onto the molten steel contained in the mold during continuous casting of the steel plays a very important role in the quality of the casting operation and the quality of the produced slab. When the thickness of the molten mold flux is reduced during the continuous casting, a breakage of the casting due to the incorporation of the molten mold flux occurs, and when the thickness is too large, the amount of consumed is reduced and the operation becomes unstable. The molten mold flux is injected at a constant thickness on the molten steel, but the carbon powder is sprayed on the injected molten mold flux with a certain thickness. The injected molten mold flux present in the middle layer can not be visually observed due to the carbon powder sprayed on the upper layer, and the thickness measurement thereof is very difficult.

Conventionally, a laser triangulation method using a laser-camera has been used as a method for non-contact measurement of the thickness of a molten mold flux. This has the advantage that it does not cause disturbance of the layer to be measured by the contactless method. However, this method assumes that the thickness of the carbon black powder sprayed on the upper layer is constantly and constantly consumed. Carbon powder sprayed by molten mold flux and molten steel at high temperature (1200 ℃ ~ 1500 ℃) is burned and solidified, causing severe scattering, and laser irradiated by scattering powder is disturbed and measurement abnormality occurs frequently. The accuracy of the triangulation method may be significantly reduced due to foreign substances growing on the inner side of the mold. In addition, laser-camera system should be actively reacted to flame generation and external illumination change in mold, but it is difficult to realize automatic change easily in realistic system.

Korean Patent Publication No. 10-2012-0045313

SUMMARY OF THE INVENTION It is an object of the present invention to provide a measuring apparatus for measuring the thickness of an intermediate layer accommodated in a container in a non-contact manner. Another object of the present invention is to provide a measuring method for precisely measuring the thickness of an intermediate layer in a container without using laser triangulation.

An embodiment of the present invention is a thickness measuring apparatus for measuring a thickness of an intermediate layer in a fluid material composed of a lower layer, an intermediate layer and an upper layer accommodated in a container, the thickness measuring apparatus comprising: a light source for irradiating laser light onto a surface of the fluid, A laser distance measuring unit for calculating a distance to the surface of the fluid using the laser light and the reflected light; A thickness calculating unit for calculating a thickness of the intermediate layer using a distance to the surface of the fluid; And a light guiding unit guiding the laser light emitted from the laser distance measuring unit to the surface of the fluid and guiding the reflected light reflected from the surface of the fluid to the laser distance measuring unit.

The laser distance measuring unit may include a laser light irradiating module located above the container and irradiating the laser light horizontally; A reflected light receiving module located on the upper side of the container and receiving reflected light reflected from the surface of the fluid; And a fluid object surface distance calculating module that calculates a distance to the surface of the fluid using the time difference between the irradiation point of the laser light and the reception point of the reflected light.

Wherein the light guiding unit includes a protection tube having one end connected to the laser distance measuring unit and the other end directed toward the surface of the fluid, and the protection pipe is connected to the laser distance measuring unit, Protective tube; And a vertical protection pipe connected to the horizontal protection pipe and extending vertically to face the surface of the fluid.

The light guiding unit includes a filter that is located on an optical path where the laser distance measuring unit and the protective tube are connected and filters and transmits only a desired wavelength band. A window positioned on the optical path of the other end of the protective tube to seal the inside of the protective tube from the outside; A heat insulating material covering an outer wall at a point where the laser distance measuring unit and the protection tube are connected to protect the laser distance measuring unit from external heat; And a cooling passage provided in the wall of the protective pipe.

The laser light is horizontally incident on the horizontal protection pipe at a connection point between the horizontal protection pipe and the vertical protection pipe and vertically reflects the laser light toward the vertical protection pipe. The reflected light incident vertically along the vertical protection pipe is horizontally And a reflecting mirror for reflecting light.

And the distance to the surface of the fluid is a distance to the surface of the upper layer.

And the distance to the surface of the fluid is a distance to the surface of the intermediate layer after removing the upper layer.

Further, an embodiment of the present invention is a thickness measuring method for measuring a thickness of an intermediate layer in a fluid material comprising a lower layer, an intermediate layer and an upper layer accommodated in a container, the thickness measuring method comprising: a step of irradiating a surface of the fluid with laser light; Receiving reflected light reflected on a surface of the fluid; Calculating a distance to the surface of the fluid using the time difference between the irradiation time of the laser light and the reception time of the reflected light; And calculating a thickness of the intermediate layer using a distance to the surface of the fluid.

The reflected light is reflected light reflected from the surface of the upper layer, and the distance to the surface of the fluid may be the distance to the surface of the upper layer.

C: speed of light, T _a: the laser light is a time difference of the reception time of the laser beam transmission point and the reflected light when the reflective hit the surface of the upper layer, L1: distance from the reflecting mirror in the laser distance measuring unit, H1 H2: Distance from the upper surface of the container to the upper surface of the lower layer, H3: Thickness of the upper layer, and H: Thickness of the middle layer , The thickness (H) of the intermediate layer can be calculated by calculating H = H 2 - (CT _a ) / 2 + L 1 + H 1 - H 3.

The lower layer and the intermediate layer are liquid liquid materials, and the upper layer is a solid liquid material.

The step of irradiating the surface of the fluid with the laser light comprises the steps of removing the solid fluid at the point irradiated with the laser light; And irradiating laser light onto the surface of the intermediate layer from which the solid liquid material is removed.

The reflected light is reflected light reflected from the surface of the intermediate layer, and the distance to the surface of the fluid may be the distance to the surface of the intermediate layer.

C: speed of light, T _b: the laser light is a time difference of the reception time of the laser beam transmission point and the reflected light when the reflective hit the surface of the intermediate layer, L1: distance from the reflecting mirror in the laser distance measuring unit, H1 H2 is a distance from the upper surface of the container to the upper surface of the lower layer, and H is a thickness of the intermediate layer, The thickness H of the intermediate layer can be calculated by H = H 2 - (CT _b ) / 2 + L 1 + H 1.

According to the embodiment of the present invention, it is possible to solve the limit of the accuracy of the laser triangulation method, which is a conventional non-contact method. Further, according to the embodiment of the present invention, measurement of easiness of measurement, accuracy of measurement, reliability of measurement and thickness control can be facilitated by measuring the thickness of the intermediate layer, for example, the thickness of the molten mold flux layer of molten steel. Therefore, it is possible to improve the operability of the continuous casting and to improve the quality of the slab.

1 is a perspective view of a thickness measuring apparatus for measuring a thickness of a molten mold flux accommodated in a mold according to an embodiment of the present invention;
2 is a cross-sectional view of a thickness measuring apparatus for measuring the thickness of a molten mold flux according to an embodiment of the present invention.
3 is a graph showing black body radiation and laser intensity.
4 is a flowchart illustrating a thickness measurement process for measuring a thickness of a molten mold flux accommodated in a mold according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know. Wherein like reference numerals refer to like elements throughout.

FIG. 1 is a perspective view of a thickness measuring apparatus for measuring a thickness of a molten mold flux accommodated in a mold according to an embodiment of the present invention, and FIG. 2 is a perspective view of a thickness measuring apparatus for measuring a thickness of a molten mold flux according to an embodiment of the present invention. Sectional view.

Hereinafter, the container will be described by taking the mold 100 in which the carbon powder, the molten mold flux, and the molten steel are sequentially accommodated. However, various containers that can accommodate various fluids other than the mold 100 may also be applicable. The molten mold flux in the intermediate layer 20 and the thickness of the molten mold flux as the intermediate layer 20 in the case where molten steel is present in the lower layer 10 as the fluid material contained in the mold 100, Will be described. However, the present invention is not limited to this, and the same can be applied to the case of measuring the thickness of the intermediate layer 20 in the fluid composed of the upper layer 30, the intermediate layer 20 and the lower layer 10.

Molten steel is present in a liquid state in the lower layer 10 existing at the bottom of the mold 100 and molten mold flux as the intermediate layer 20 is present in a liquid state on the molten steel of the lower layer 10, On top of the mold flux, carbon powder, which is the upper layer 30, exists in the form of solid powder. The molten mold flux present in the intermediate layer 20 in the mold 100 serves as a lubricant that enables continuous casting to be performed stably and the carbon powder present in the upper layer 30 maintains the melt surface temperature of the mold 100 It acts as a thermal insulation. When the thickness of the molten mold flux is reduced during the continuous casting, a breakage of the casting due to the incorporation of the molten mold flux occurs, and when the thickness is too large, the amount of consumed is reduced and the operation becomes unstable. Therefore, the thickness of the molten mold flux should be kept constant as the set thickness. The embodiment of the present invention calculates the thickness of the molten mold flux using only the laser in the mold 100 containing the molten steel. The thickness measuring apparatus of the present invention for calculating the thickness of the molten mold 100 plus may include a laser distance measuring unit 200, a light guiding unit, and a thickness calculating unit.

The laser distance measuring unit 200 irradiates the laser light onto the surface of the fluid, receives the reflected light reflected from the surface of the fluid, and calculates the distance to the surface of the fluid using the laser light and the reflected light. The laser light is irradiated to the surface of the fluid to receive the reflected light reflected from the surface of the fluid and the distance from the laser distance measuring unit 200 to the surface of the fluid is calculated. The laser distance measuring unit 200 may be supported by a separate support (not shown) and positioned above the mold 100.

The laser distance measuring unit 200 includes a reflected light irradiation module (not shown), a reflected light reception module (not shown), and a fluid surface distance calculation module (not shown). The laser light to be irradiated may be a green region of 532 nm or a red region of 635 nm. A reflected light irradiation module (not shown) is placed on the upper side of the container and irradiates laser light horizontally. The laser light irradiated horizontally travels horizontally along the horizontal protective pipe 210a of the light guiding portion and is reflected through the reflective mirror 250 and travels vertically along the vertical protective pipe 210b to move the fluid contained in the mold 100 Surface.

The reflected light receiving module (not shown) is located on the upper side of the mold 100 and receives the reflected light reflected from the surface of the fluid. Reflected light is light reflected by the laser light, and has the same wavelength band as the laser light. Reflected light reflected from the surface of the fluid moves vertically along the vertical protective pipe 210b of the light guiding part and is reflected through the reflective mirror 250 and horizontally moves along the horizontal protective pipe 210a to be reflected by the reflected light receiving module ). ≪ / RTI >

The fluid surface distance calculation module (not shown) can calculate the distance to the surface of the fluid using the time of flight between the irradiation point of the laser light and the reception point of the reflected light. For reference, the velocity has a relation of distance ÷ time, so it can be calculated by the following equation (the traveling distance of laser light + the traveling distance of reflected light) = light speed (C) × time difference (T) Therefore, it can be calculated by "distance from the laser distance measuring unit (laser light irradiation module) to the surface of the fluid = (traveling distance of laser light + travel distance of reflected light) 2 = (light speed × time difference) / 2".

The light guiding part guides the laser light emitted from the reflected light irradiation module (not shown) of the laser distance measuring part 200 to the surface of the fluid contained in the mold 100 and reflects the reflected light reflected from the surface of the fluid To a reflected light receiving module (not shown) of the laser distance measuring unit 200. [ To this end, the light guiding unit includes a protective tube 210 having one end connected to the laser distance measuring unit 200 and the other end directed toward the surface of the fluid.

The protective tube 210 minimizes the scattering of the laser light in the optical path from the external environment to secure the accuracy and reliability of the distance measurement. To this end, the protective pipe 210 is connected at one end to the laser distance measuring unit 200 and at the other end toward the surface of the fluid. The protective pipe 210 is connected to the laser distance measuring unit 200 and includes a horizontal protection pipe 210a extending horizontally and a vertical protection pipe 210b connected to the horizontal protection pipe 210a and extending vertically so as to face the surface of the fluid, . A reflection mirror 250 is disposed inside the connection point between the horizontal protection tube 210a and the vertical protection tube 210b to reflect the light. The reflection mirror 250 is positioned at a connection point between the horizontal protection pipe 210a and the vertical protection pipe 210b and is irradiated with laser light emitted from the laser distance measurement unit 200 horizontally along the horizontal protection pipe 210a, Or horizontally reflects the reflected light that is vertically incident on the surface of the fluid along the vertical protection pipe 210b toward the horizontal protection pipe 210a.

The laser light emitted from the reflection light irradiation module (not shown) of the laser distance measuring unit 200 travels along the horizontal protection pipe 210a and is reflected by the reflection mirror 250 to travel along the vertical protection pipe 210b, 100). ≪ / RTI > The reflected light reflected from the surface of the fluid moves along the vertical protection pipe 210b and is reflected by the reflection mirror 250 and travels along the horizontal protection pipe 210a to be reflected by the reflection light receiving module (not shown) As shown in FIG.

The light guiding unit may further include a filter 220, a window, a heat insulating material 230, and a cooling channel (not shown) in addition to the protective tube 210 and the reflecting mirror 250 described above.

The filter 220 is positioned on an optical path at a point where the laser distance measuring unit 200 and the protective pipe 210 are connected to filter and transmit only a desired wavelength band. The filter 220 selectively transmits the laser light, and is selectively used in accordance with the wavelength of the laser used. The intensity of laser light may be disturbed by the blackbody radiation radiated in the mold 100, so that the desired wavelength band can be filtered using the filter 220. Also, as shown in FIG. 3, the radiation intensity at a black body temperature of 1000 to 1500K is very weak compared to the intensity of the laser light, and can be ignored.

The window 240 is located on the optical path of the other end of the protective pipe 210 adjacent to the surface of the fluid, and can seal the inside of the protective pipe 210 from the outside. The window 240 seals the protective tube 210 from the external environment and smoothly transmits laser light. Considering the high heat of the mold 100 and the transparency of laser light, a window 240 made of quartz material or sapphire can be used.

The heat insulating material 230 may surround the outer wall of the point where the laser distance measuring unit 200 and the protective pipe 210 are connected to each other to protect the laser distance measuring unit 200 from external heat. A cooling channel (not shown) is provided on the wall of the protection pipe 210 to cool the protection pipe 210. The direction of the cooling channel (not shown) may be a path through which the laser distance measuring unit 200 is connected to the protective pipe 210 and is output from the protective pipe 210 contacting the fluid of the mold 100. The cooling channel (not shown) uses a gas cooling method using compressed air, nitrogen, or the like. Cooling by cooling water is efficient, but cooling of the gas is safer because explosion may occur in the mold 100 due to the cooling water flowing into the mold 100 when the cooling water flow path breaks.

As a result, the thickness measuring apparatus according to the present invention includes a protective tube 210 for preventing scattering of laser light, a reflecting mirror 250 for reflecting the laser beam, a cooling channel (not shown) for cooling the protective tube 210, A window 240 through which laser light is transmitted, and the like. Therefore, a protective pipe 210 is used to solve the degradation of the light intensity due to the scattering of the laser beam, and a gas cooling channel is formed to prevent the temperature rise of the protective pipe 210 due to radiant heat transmitted from the mold 100.

The thickness calculating section can calculate the thickness of the molten mold flux which is the intermediate layer 20 by using the distance to the surface of the fluid to be measured using the laser light. Before describing an example of calculating the thickness of the molten mold flux which is the intermediate layer 20 of the fluid substance, the thickness calculating unit is a unit that can be operated like a computer equipped with a CPU and describes the definition of each parameter shown in Fig. 2 do.

(1) First reference point: a reference point serving as a measurement reference, the height of the upper surface of the mold cover

(2) Second reference point: The reference point serving as a measurement reference, the height of the boundary line between the molten steel contained in the mold and the molten mold flux

For reference, the first reference point and the second reference point can be grasped by an ECLM (EDDY CURRENT LEVEL METER) apparatus that detects the height level of molten steel in the mold during continuous casting and controls the molten steel height.

(3) First reflection point: height of the surface of the carbon powder when laser light is reflected from the surface of the carbon powder which is the upper layer of the fluid contained in the mold

(4) Second Reflection Point: A case where the laser light is reflected on the surface of the molten mold flux which is the intermediate layer of the fluid contained in the mold, and the height of the surface of the molten mold flux

For reference, in order to reflect the laser light on the surface of the molten mold flux, the carbon powder must be locally removed to the surface of the molten mold flux, which is the point where the laser light is irradiated by a mechanical operation or an operator.

(5) L1: Reflected light from the laser distance measuring unit Distance from the reflecting unit to the reflecting mirror

(6) L2 ': distance from the reflecting mirror to the surface of the carbon powder which is the upper layer of the fluid

(7) L2 ": distance from the reflecting mirror to the surface of the molten mold flux which is the middle layer of the fluid

(8) H1: The distance from the height of the laser beam traveling horizontally along the horizontal protection tube to the height of the cover top surface (first reference point) of the mold, that is, the height of the laser light oscillation point of the reflected light irradiation module (First reference point) of the upper surface of the cover

H1 is a distance from the height of the reflected light receiving point of the reflected light receiving module (not shown) to the upper surface of the cover of the mold (not shown) because the reflected light irradiating module (not shown) and the reflected light receiving module (not shown) (First reference point) may also be applicable.

(9) H2: Distance from the first reference point to the second reference point, that is, the distance from the upper surface (first reference point) of the mold cover to the upper surface of the molten steel as the lower layer 10

(10) H3: Thickness of the carbon powder as the upper layer

(11) H4 ': Height from the height of the upper surface of the cover (first reference point) of the mold to the upper surface of the upper layer of carbon powder contained in the mold

(12) H4 ": height from the height (first reference point) of the upper surface of the cover of the mold to the upper surface of the molten mold flux

(13) H: Thickness of the molten mold flux as an intermediate layer in the mold

In the above, H is the thickness of the molten mold flux to be measured in the present invention, H1 is a fixed value that can be grasped at the time of mounting the equipment of the laser distance measuring unit, H2 is a fixed value that can be grasped as an ELCM output value, Is a fixed value that assumes that constant carbon powder is injected as a value that can be grasped by the amount of carbon powder charged. H " and H "are fluctuations that can vary depending on the thickness of the molten mold flux.

(14) C: speed of light

(15) T _a : a time difference between the transmission time of the laser light and the reception time of the reflected light when the laser light is reflected on the surface of the upper layer carbon powder

(16) T _b: the laser light transmission time difference between the reception point in time of the reflected light when the laser light is reflected to hit the surface of the molten mold flux intermediate

(17) L: total travel distance of laser light,

   L = (L1 + L2 ') x 2 when reflected on carbon powder as an upper layer,

   L = (L1 + L2 ") x 2 < / RTI >

   (Where L1 is a fixed value, L2 'and L2 "are variations)

(18) T: time of flight of laser light and reflected light, T = L / C

(19) The distance (L1 + L2 ') from the surface of the fluid to the surface of the fluid calculated by the laser distance measuring unit when it is reflected on carbon powder as an upper layer = C × T _a ÷ 2

(20) The distance (L1 + L2 ") from the laser distance measuring unit to the surface of the fluid produced when it is reflected on the molten mold flux which is the intermediate layer = C × T _b ÷ 2

Referring to the parameter definitions (1) to (20) related to the height as described above, the thickness calculating unit calculates the thickness of the molten mold flux as the intermediate layer 20 by using the distance to the surface of the fluid measured using the laser light Can be calculated.

The distance to the surface of the fluid to be measured using the laser beam thickness calculating unit can be measured to the surface of the carbon powder which is the upper layer 30 or the molten mold flux as the intermediate layer 20, Can be measured. Therefore, in the embodiment of the present invention, the thickness of the molten mold flux, which is the intermediate layer 20, can be calculated by using the distance to the surface of the carbon powder measured through the laser beam thickness calculating unit or by using the distance to the surface of the molten mold flux have.

First, an example will be described in which the thickness of the molten mold flux, which is the intermediate layer 20, is calculated by using the distance to the surface of the carbon powder, which is the upper layer 30, measured through the laser beam thickness calculating section. When the distance to the surface of the carbon powder which is the upper layer 30 is used, the thickness H of the molten mold flux has a relation of the following [Equation 1].

[Formula 1]

H = H2 - H4 '- H3 (where H2, H3 are fixed values and H4' is a variation value)

  = H2 - (L2 - H1) - H3

= H 2 - (C x T _a ÷ 2 - L 1 - H 1) - H 3

= H2 - C * T _a2 + L1 + H1 - H3

Therefore, in the final expression of [Equation 1], the variable remains only at time T, and the thickness of the molten mold flux to be measured can be calculated. For reference, it is assumed that the thickness H3 of the carbon powder is known by the operating standards. That is, the thickness of the carbon powder can be known from the input amount of the carbon powder standardized for operation.

On the other hand, an example of calculating the thickness of the molten mold flux, which is the intermediate layer 20, by using the distance to the surface of the molten mold flux, which is the intermediate layer 20, measured through the laser beam thickness calculating section will be described. When the distance to the surface of the molten mold flux which is the intermediate layer 20 is used, the thickness H of the melt mold 100 flux has a relation of the following formula (2).

[Formula 2]

H = H2 - H4 "(where H2 is a fixed value and H4" is a variation value)

  = H2 - (L2 "- H1)

_{= H2 - (C × T b} ÷ 2 - L1 - H1)

_{= H2 - C × T b ÷} 2 + L1 + H1

4 is a flowchart illustrating a thickness measurement process for measuring a thickness of a molten mold flux accommodated in a mold according to an embodiment of the present invention.

When the liquid material contained in the mold 100 contains liquid molten steel in the lower layer 10, molten mold flux in the liquid phase in the intermediate layer 20 and solid carbon powder in the upper layer 30, the molten mold flux The surface of the fluid is irradiated with laser light (S410).

The surface of the fluid to be irradiated with the laser light may be the surface of the carbon powder which is the upper layer 30. Or the carbon powder as the upper layer 30 is locally removed by a mechanical operation or a manual operation so that the surface of the molten mold flux as the intermediate layer 20 can be irradiated with laser light. Therefore, in order to irradiate the surface of the molten mold flux, which is the intermediate layer 20, with laser light, a process of removing carbon powder, which is a solid fluid material in the upper layer 30 at a position where laser light is irradiated, And irradiating the surface of the substrate 20 with a laser beam.

The laser light irradiated on the surface of the fluid is reflected by the surface of the fluid and the reflected light is received (S420). That is, the reflected light reflected from the surface of the carbon powder which is the upper layer 30 or the reflected light reflected from the surface of the molten mold flux which is the intermediate layer 20 can be received.

When the reflected light is received, the distance to the surface of the fluid is calculated using the time difference between the irradiation point of the laser light and the reflection point of the reflected light (S430). The distance to the surface of the carbon powder is calculated when reflected from the surface of the carbon powder as the upper layer 30 and the distance to the surface of the molten mold flux when reflected from the surface of the molten mold flux as the intermediate layer 20 Can be calculated.

For example, when the distance from the reflection light irradiation module (not shown) to the surface of the carbon powder as the upper layer 30 is calculated, it can be calculated as (L1 + L2 ') = C x T _a 2 (L1 + L2 ") = C × T _b ÷ 2 when the distance from the reflection light irradiation module (not shown) to the surface of the molten mold flux as the intermediate layer 20 is calculated.

After calculating the distance to the surface of the carbon powder or the distance to the surface of the molten mold flux, the thickness of the intermediate layer 20 is calculated (S440).

When the reflected light is reflected on the surface of the carbon powder which is the upper layer 30, the thickness of the molten mold flux which is the intermediate layer 20 can be calculated by the relational expression of [Equation 1] described above.

When the reflected light is reflected from the surface of the molten mold flux which is the intermediate layer 20, the thickness of the molten mold flux which is the intermediate layer can be calculated by the relational expression of [Equation 2] described above.

Although the present invention has been described with reference to the accompanying drawings and the preferred embodiments described above, the present invention is not limited thereto but is limited by the following claims. Accordingly, those skilled in the art will appreciate that various modifications and changes may be made thereto without departing from the spirit of the following claims.

10: lower layer 20: middle layer
30: upper layer 100: mold
200: laser distance measuring unit 210: protective tube
220: Filter 230: Insulation
240: Window 250: Reflective Mirror
300: thickness calculating section

Claims (14)

1. A thickness measuring device for measuring a thickness of an intermediate layer in a fluid material composed of a lower layer, an intermediate layer and an upper layer accommodated in a container,
A laser distance measuring unit that irradiates laser light onto a surface of the upper layer to receive reflected light reflected from a surface of the upper layer and calculates a distance to an upper layer surface using the laser light and reflected light;
A thickness calculating unit for calculating a thickness of the intermediate layer by using a distance to the surface of the upper layer;
And a light guiding unit guiding the laser light emitted from the laser distance measuring unit to the surface of the upper layer and guiding the reflected light reflected from the surface of the upper layer to the laser distance measuring unit,
The light guiding portion includes:
A protective tube having one end connected to the laser distance measuring part and the other end directed to the surface of the upper layer; And a window positioned on the optical path at the other end of the protective tube to seal the inside of the protective tube from the outside,
The thickness calculating unit may calculate,
The distance from the oscillation point of the laser light which is a fixed value to the upper surface of the lower layer and the thickness of the upper layer and the distance to the surface of the upper layer which is a value measured using only the laser light, However,
Wherein the laser beam is irradiated onto the surface of the powder layer as the upper layer.
[2] The apparatus according to claim 1,
A laser light irradiation module positioned above the container and irradiating the laser light horizontally;
A reflected light receiving module located on the upper side of the container and receiving reflected light reflected from a surface of an upper layer;
A fluid material surface distance calculating module that calculates a distance to the surface of the upper layer using a time difference between the irradiation point of the laser light and the reflection point of the reflected light;
.
[2] The apparatus according to claim 1,
A horizontal protection pipe connected to the laser distance measurement unit and extending horizontally;
A vertical protection pipe connected to the horizontal protection pipe and extending vertically so as to face the surface of the upper layer;
.
4. The light guide plate according to claim 3,
A filter positioned on the optical path where the laser distance measuring unit and the protective tube are connected and filtering and transmitting only a desired wavelength band;
A heat insulating material covering an outer wall at a point where the laser distance measuring unit and the protection tube are connected to protect the laser distance measuring unit from external heat;
A cooling passage provided in a wall of the protective pipe;
.
The method of claim 3,
The laser light is horizontally incident on the horizontal protection pipe at a connection point between the horizontal protection pipe and the vertical protection pipe and vertically reflects the laser light toward the vertical protection pipe. The reflected light incident vertically along the vertical protection pipe is horizontally Reflecting mirror;
.
The method of claim 5,
C: speed of light,
T _a : a time difference between the transmission time of the laser light and the reception time of the reflected light when the laser light is reflected on the surface of the upper layer,
L1 is a distance from the laser distance measuring unit to the reflection mirror,
H1 is the distance from the height of the laser beam incident horizontally along the horizontal protection tube to the height of the upper surface of the container,
H2: Distance from upper surface of container to upper surface of lower layer,
H3: thickness of the upper layer,
H: thickness of the intermediate layer,
, The thickness calculating section calculates the thickness
H = H 2 - (CT _a ) / 2 + L 1 + H 1 - H 3
To calculate the thickness (H) of the intermediate layer.
delete 1. A thickness measuring method for measuring a thickness of an intermediate layer in a fluid material composed of a lower layer, an intermediate layer and an upper layer accommodated in a container,
A step of irradiating a surface of the upper layer with the laser light proceeding along a protective tube whose one end is connected to the laser distance measuring part and the other end is directed to the surface of the fluid and the other end is closed by a window;
And advancing and reflecting reflected light reflected by the surface of the upper layer along the protection tube;
Calculating a distance to the surface of the upper layer by using a time difference between the irradiation time of the laser light and the reception time of the reflected light;
And calculating a thickness of the intermediate layer using a distance to the surface of the upper layer,
The process of calculating the thickness of the intermediate layer may include:
The thickness of the intermediate layer is calculated by using the distance from the oscillation point of the laser light as the fixed value to the upper surface of the lower layer and the thickness of the upper layer and using the distance to the surface of the upper layer as a value measured using only the laser light In addition,
Wherein the laser beam is irradiated onto the surface of the powder layer as the upper layer.
delete The method of claim 8,
The protective tube is connected to the laser distance measuring unit and extends horizontally and horizontally. The vertical protection tube is vertically extended to the surface of the upper layer. The vertical protection tube is disposed inside the connection point between the horizontal protection tube and the vertical protection tube. Including a reflective mirror,
C: speed of light,
T _a : a time difference between the transmission time of the laser light and the reception time of the reflected light when the laser light is reflected on the surface of the upper layer,
L1 is a distance from the laser distance measuring unit to the reflection mirror,
H1 is the distance from the height of the laser beam incident horizontally along the horizontal protection tube to the height of the upper surface of the container,
H2: Distance from upper surface of container to upper surface of lower layer,
H3: thickness of the upper layer,
H: thickness of the intermediate layer,
, It is preferable that the thickness of the intermediate layer is calculated,
H = H 2 - (CT _a ) / 2 + L 1 + H 1 - H 3
And the thickness (H) of the intermediate layer is calculated.
The method of claim 8,
Wherein the lower layer and the middle layer are liquid liquid materials, and the upper layer is a solid liquid material.
delete delete delete

Images