JP3155229B2 - Method and apparatus for measuring tilt angle of free surface of particulate layer in deposited state - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring a tilt angle of a free surface of a granular layer in a deposited state.

[0002]

2. Description of the Related Art In general, when planning and designing a powder and granule treatment process and quality control of a powder and granule, it is important to fully understand the flow characteristics and jet flow characteristics of the powder and granules to be handled. The evaluation of these characteristics is performed based on various physical property values such as the angle of repose and the angle of the spatula of the particulate layer in the deposited state. Conventional measurements of the angle of repose and spatula angle have been performed by applying a protractor to the free surface of the granular material layer and reading the scale.

[0003]

However, in the above-mentioned measuring method, when the free surface of the granular material layer is not flat, various methods of applying the protractor can be considered. There is a problem in that when a plurality of operators measure the same object, the measured values are reflected in the measured values, and the measured values vary. In addition, there is also a problem that it takes time to determine how to apply the protractor, and it takes time to perform the measurement.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to measure the inclination angle of the free surface of a granular material layer in a deposited state by using a unique habit of an operator. An object of the present invention is to eliminate variations in measured values that occur and to reduce labor and time required for measurement.

[0005]

In order to achieve the above object, the invention according to claim 1 is to emit a light beam to the side of a powdery or granular material layer which is conically deposited on a horizontal plane, and is irradiated with the light beam. A sensor for detecting the distance to the point, the light beam exit port is disposed so as to face the free surface of the granular material layer and the optical axis of the light beam is horizontal, the sensor to the optical axis Move in a horizontal direction perpendicular to the free surface and detect a distance between a plurality of points linearly arranged from one end to the other end in the horizontal direction along a line facing the movement path of the sensor. The process is performed a plurality of times by moving the sensor by a predetermined distance in the vertical direction, extracting points at which the distance from the sensor in each step is the minimum, and calculating a function of a straight line approximating a locus composed of these points by a minimum of two. The slope of the straight line with respect to the horizontal plane, obtained by multiplication Is a measurement method characterized by calculating a degree.

According to a second aspect of the present invention, a sensor for emitting a light beam and detecting a distance from a point irradiated with the light beam is provided above the granular material layer deposited conically on a horizontal plane. Is arranged such that the optical axis of the light beam is perpendicular to the free surface of the granular material layer, and the sensor is moved horizontally in a vertical plane including the apex of the granular material layer. Then, the distance between a plurality of points arranged at predetermined intervals in the horizontal direction along the ridge line of the granular material layer is detected, and a function of a straight line approximating a locus composed of these points is determined by the least square method. And measuring the inclination angle of the straight line with respect to the horizontal plane.

According to a third aspect of the present invention, in the measuring method of the second aspect, the sensor is moved in the horizontal direction in the vertical plane so that a predetermined interval is provided in the horizontal direction along the ridge line of the granular material layer. Detecting the distance between the plurality of points arranged in the above, obtaining a function of a straight line approximating the locus of these points by the least squares method, and calculating the inclination angle of the straight line with respect to the horizontal plane The method is performed on both sides of the vertex of the layer, and an average value of the inclination angles obtained in each of the steps is calculated.

According to a fourth aspect of the present invention, there is provided a sensor for emitting a light beam to the side of a granular material layer deposited on a horizontally supported spatula and detecting a distance from a point irradiated with the light beam. The light beam exit port faces the free surface of the granular material layer and the optical axis of the light beam is arranged to be horizontal, and the sensor is moved vertically to move the sensor on the free surface. A distance between a plurality of points arranged at predetermined intervals in a vertical direction along a line facing the moving path is detected, and a function of a straight line approximating a locus composed of these points is obtained by a least square method. This is a measuring method characterized by calculating an inclination angle of a straight line with respect to a horizontal plane.

According to a fifth aspect of the present invention, in the measuring method according to the fourth aspect, the sensor is moved in a vertical direction so that the sensor moves vertically on the free surface along a line facing a movement path of the sensor. Detecting the distance between a plurality of points arranged at intervals, obtaining a function of a straight line approximating a locus composed of these points by the least squares method, and calculating an inclination angle of the straight line with respect to a horizontal plane. Is performed in a plurality of places by moving the spatula in the longitudinal direction, and an average value of the inclination angles obtained in the respective steps is calculated.

According to a sixth aspect of the present invention, there is provided a light emitting device, wherein a light beam is arranged in a horizontal direction toward a horizontal surface and a free surface of the granular material layer which is disposed conically on the horizontal surface. A sensor that detects the distance between the point at which the light beam is emitted and emitted, a moving unit that moves the sensor in a horizontal direction and a vertical direction perpendicular to the optical axis of the light beam, and controls the sensor and the moving unit. A plurality of points arranged in a line from one end to the other end in the horizontal direction along a line facing the movement path of the sensor on the free surface of the granular material layer by moving the sensor in the horizontal direction. The step of detecting the distance to the sensor is performed a plurality of times by moving the sensor in the vertical direction by a predetermined distance, and a point at which the distance to the sensor in each step is minimum is extracted and approximated to a locus composed of these points. The function of the straight line is obtained by the least square method, A measuring device which is characterized in that a control means for calculating an inclination angle relative to the horizontal plane of the line.

According to a seventh aspect of the present invention, a light beam is emitted above a horizontal plane and a particle layer which is conically deposited on the horizontal plane and directed toward a free surface of the particle layer. A sensor for detecting a distance from a point irradiated with the light beam, moving means for moving the sensor in a horizontal direction in a vertical plane including a vertex of the granular material layer, and controlling the sensor and the moving means. Moving the sensor in the horizontal direction to detect distances from a plurality of points arranged at predetermined intervals in the horizontal direction along the ridge line of the granular material layer, and approximates a locus composed of these points. Control means for obtaining a function of a straight line by a least square method and calculating an inclination angle of the straight line with respect to a horizontal plane.

According to an eighth aspect of the present invention, in the measuring apparatus of the seventh aspect, the control means moves the sensor in a horizontal direction in the vertical plane so that the sensor moves horizontally along a ridge line of the granular material layer. Calculating a distance to a plurality of points arranged at predetermined intervals in the direction, obtaining a function of a straight line approximating a locus composed of these points by a least square method, and calculating an inclination angle of the straight line with respect to a horizontal plane Is performed on both sides of the vertex of the granular material layer, and an average value of the inclination angles obtained in the respective steps is calculated.

According to a ninth aspect of the present invention, there is provided a spatula supported horizontally, and a spatula disposed on a side of a granular material layer deposited on the spatula and extending horizontally toward a free surface of the granular material layer. A sensor that emits a light beam and detects a distance from a point irradiated with the light beam, a moving unit that moves the sensor in the vertical direction, and controls the sensor and the moving unit to move the sensor in the vertical direction. A function of a straight line that detects a distance to a plurality of points arranged at predetermined intervals in the vertical direction along a line facing the movement path of the sensor on the free surface and approximates a locus composed of these points And a control means for calculating the inclination angle of the straight line with respect to the horizontal plane by using the least square method.

According to a tenth aspect of the present invention, in the ninth aspect, the moving means is capable of moving the sensor in a longitudinal direction of the spatula, and the control means is configured to move the sensor in a vertical direction. Detecting the positions of a plurality of points arranged at predetermined intervals in the vertical direction along a line facing the movement path of the sensor on the free surface, and the inclination angle of a straight line obtained from these points with respect to a horizontal plane Is calculated at a plurality of locations by moving the sensor in the longitudinal direction of the spatula, and calculating an average value of the inclination angles obtained by the respective steps. .

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front view of the measuring apparatus of the present embodiment, FIG. 2 is an explanatory view of the structure and measurement principle of the sensor, FIG. 3 is an explanatory view of the measuring method of the present embodiment, FIG. 4 is a front view of the shocker, and FIG. It is a side view of a spatula angle measurement unit.

The measuring apparatus 1 shown in FIG. 1 has seven physical property values considered to be the main factors of the flow characteristics and the jet characteristics of the granular material, that is, the repose angle, the compression degree, the spatula angle, the cohesion degree, the collapse angle,
The power supply switch 2 for turning on / off the power is provided at the lower left of the apparatus. A measuring unit is provided on the right side of the measuring device 1, and a transparent synthetic resin door 3 is attached to a front surface thereof.

A vibrating unit 4 for operating a vibrating sieve on the sample powder at the time of measuring the angle of repose is provided above the measuring unit. The vibration unit 4 is mounted on a vibration table 5, a funnel 6 for measuring the angle of repose, and a sieve 7 disposed above the funnel 6.
And a cap 8 disposed thereabove. Above the vibration unit 4, a sample supply funnel 9 for supplying sample particles is disposed. The cap 8 is for temporarily storing the granular material supplied from the sample supply funnel, and has the same shape as the sieve 7 but does not have a net. The vibrating table 5 extends in a direction perpendicular to the plane of FIG. 1 and one end thereof is supported by the apparatus main body. An adsorber (not shown) is attached to the lower surface of the vibrating table 5, and this adsorber is connected to an electromagnet (not shown) attached to the apparatus main body via a cushion material, and energizes and shuts off the electromagnet. Is repeated, the vibrating table 5 vibrates in the vertical direction. Reference numeral 10 is an amplitude adjusting knob for adjusting the amplitude of the vibration table 5.

A measurement base 11 that forms the bottom surface of the measurement section
Has a seat (not shown) on which the rectangular bat 12 is placed. Inside the rectangular bat 12, a circular table for measuring the angle of repose 13 shown in FIG. 1, a unit for measuring bulk specific gravity (not shown), and a cup for measuring loose and solid apparent specific gravity (not shown)
And a shocker 20 (see FIG. 4) to be described later are arranged. The upper surface of the table 13 for measuring the angle of repose is a horizontal plane. At the time of measuring the spatula angle, a spatula angle measuring unit 21 (see FIG. 5) to be described later is arranged in place of the repose angle measuring table 13 and the guide member 14. Reference numeral 15 denotes a lift bar for moving the measurement cup up and down.

A sensor 16 is disposed on the left side of the portion where the repose angle measuring table 13 and the spatula angle measuring unit 21 are disposed. The sensor 16 is the moving block 1
7, the moving block 17 is moved by an actuator 18 in a horizontal direction and a vertical direction perpendicular to the plane of FIG. As shown in FIG. 2, the sensor 16 includes a light emitting element 16a and a light position detecting element 1.
6b, and a light emitting diode or a semiconductor laser is used for the light emitting element 16a. The light from the light emitting element 16a is condensed by the condenser lens 16c and
d, a light beam is emitted in the horizontal direction (right direction in FIG. 1) as a light beam, and is radiated in the form of a spot on the object W to be measured.
A part of the light beam diffusely reflected from the light enters the sensor 16 through the light receiving port 16e, and forms a spot on the light position detecting element 16b through the light receiving lens 16f. Thereby, the sensor 16 detects the distance to the light irradiation point on the workpiece W.

In this embodiment, the sensor 16 is a laser displacement sensor Z4M-W100 manufactured by OMRON Corporation.
RA is used. The measurement distance of this sensor 16 is 1
A point outside this range at 00 ± 40 mm is not detected. As shown in FIG. 3A, the distance between the sensor 16 and the edge of the repose angle measuring table 13 facing the sensor 16 is set to 95 mm, and the diameter of the table 13 is 80 mm.
mm. Other measuring members and the like around the table 13 are as follows.
The sensor 16 is located outside the measurement range of the sensor 16,
Does not detect anything other than the granular material layer P deposited on the table 13 and can obtain an accurate measurement result. In addition, a sensor other than the above can also be used.

As shown in FIG. 1, a computer 19 for controlling a measuring unit, a sensor 16, an actuator 18, and other parts is provided at an upper left portion of the measuring apparatus 1. The computer 19 includes operation keys including a touch panel and a display unit including an LCD.

The shocker 20 shown in FIG. 4 is used at the time of measuring the collapse angle. The shocker 20 has a pole 23 erected vertically on the upper surface of a circular pedestal 22, and a through hole 24a in the center where the pole 23 penetrates. And a circular weight 24 disposed on the pedestal 22. When the weight 24 is lifted up to the upper end of the pole 23 by hand and released, the weight 24 falls freely and the pedestal 2
2 is to be shocked.

A spatula angle measuring unit 21 shown in FIG.
Is a pole 25 vertically erected on a pedestal (not shown).
And a spatula 26 having one end attached to the pole 25 so as to extend in the left-right direction of FIG.
Is provided with a circular weight 27 disposed above the spatula 26. When the weight 27 is lifted up to the upper end of the pole 25 by hand and released, the weight 27
Fall freely and give an impact to the spatula 26. The spatula angle measuring unit 21 includes a rectangular bat 12 between the rectangular bat 12 and the rear wall of the measuring unit (the portion indicated by oblique lines in FIG. 5) on which the powder P on the tip side of the spatula 26 is placed. 12 so as to protrude.

Next, the operation of the measuring apparatus 1 configured as described above will be described. First, a case where the angle of repose is measured will be described.

After setting the repose angle measurement mode by the operation keys of the computer 19, the door 3 is opened, and the repose angle measurement table 13 is placed in the rectangular bat 12 so as to be located directly below the repose angle measurement funnel 6. . When measuring the collapse angle continuously, the shocker 20 is moved to the rectangular butt 1.
2 is arranged near the table 13 for measuring the angle of repose. Then, the sample powder is supplied into the sample supply funnel 9 and deposited on the sieve 7 of the vibration unit 4.

When the door 3 is closed and the operation key of the computer 19 is pressed to vibrate the vibration unit 4,
And starts to accumulate on the upper surface of the table 13 for measuring the angle of repose. Then, when a conical deposition layer is formed on the table 13, the operation key of the computer 19 is pressed to stop the vibration of the vibration unit 4.

Next, when an instruction to start the measurement of the angle of repose is input from the operation keys of the computer 19, the actuator 18
Moves the sensor 16 to a position facing one end of the lower end of the free surface of the granular material layer deposited on the table 13, and then moves the sensor 16 to a position facing the other end of the lower end of the granular material layer. To move horizontally. The sensor 16 emits a laser beam while moving, and the sensor 1 is placed on the free surface of the granular material layer P.
The distance between a plurality of points arranged in a line at a minute interval 移動 X (see FIG. 3 (a)) from one end to the other end in the horizontal direction along the line facing the movement path of No. 6 is sequentially determined. To detect.
This measurement result is stored in the memory of the computer 19.

Next, the actuator 18 raises the sensor 16 by .DELTA.Y in the vertical direction, then horizontally moves the sensor 16 in the opposite direction, and the sensor 16 faces the sensor 16 in the same manner as described above. The distance to a plurality of points lined up linearly is detected. As described above, the step of detecting the position of a point on the free surface of the granular material layer P by moving the sensor 16 in the horizontal direction is performed by moving the sensor 16 vertically upward by ΔY at a time. It is done over the entire length.

Next, the computer 19 extracts points having the minimum distance from the sensor 16 in each step, and obtains a function of a straight line approximating a locus composed of these points by the least square method. That is, as shown in FIG. 6, when these points are plotted on a graph in which the horizontal axis represents the distance to the sensor and the vertical axis represents the vertical distance from the lowest point, as shown by the solid line, It becomes a substantially linear locus. Computer 19
Calculates a function of a straight line L approximating the solid line by the least squares method, calculates an inclination angle of the straight line L with respect to a horizontal plane, and displays the inclination angle of the free surface of the granular material layer P on the display unit.

When the collapse angle is subsequently measured, the operation mode of the computer 19 is used to set the collapse angle measurement mode. Then, the weight 24 of the shocker 20 is lifted up to the upper end of the pole 23 to drop the weight 24 onto the pedestal 22, and the operation of giving an impact to the rectangular bat 12 is performed three times. As a result, the granular material layer P deposited on the table 13 collapses, and its free surface exhibits a smaller inclination angle. When an instruction to start measurement is input with the operation keys, the inclination angle of the free surface of the granular material layer P is measured in the same procedure as when the angle of repose is measured, and is displayed on the display unit as the collapse angle.

When the difference angle is subsequently calculated, by setting the operation mode to the difference angle measurement mode, the difference between the repose angle and the collapse angle stored in the memory is calculated and displayed on the display unit as the difference angle. You.

FIG. 7 is a graph showing the results of measuring the inclination angle (angle of repose) a plurality of times for various powders without changing the deposition state. According to this, it can be seen that there is little variation in the measured values and an almost constant value is obtained.

According to the present invention, the inclination angle is measured based on a certain standard called the least squares method without the work of hitting the protractor along the free surface of the granular material as in the prior art. The result is not reflected in the value, and the same result is obtained even when the measurer changes. In addition, since there is no complicated operation as described above, the measurement does not take much time and the time required for the measurement is short.
It took about 30 seconds, but in this embodiment, about 1
0 seconds).

Next, the case of the spatula angle measurement will be described. After setting the spatula angle measurement mode with the operation key of the computer 19, the door 3 is opened, and the spatula angle measurement unit 21 is moved to the rectangular bat 1 as shown in FIG.
2 and the rear wall of the measuring unit, and the lift bar 15 raises the rectangular bat 12 to a position where the bottom surface of the rectangular bat 12 is in contact with the lower surface of the granular material mounting portion 26 a of the spatula 26. Then, the sample powder P is placed in the powder receiver 2 by a spoon or the like.
6a, the rectangular bat 12 is lowered by the lift bar 15.

When an instruction to start measurement is input by operating keys, the actuator 18 causes the sensor 16 to operate the spatula 2.
Then, the sensor 16 is moved vertically downward and then the sensor 16 is moved vertically downward. The sensor 16 emits a laser beam while moving, and a distance between a plurality of points vertically arranged at predetermined intervals along a line facing the movement path of the sensor 16 on the free surface of the granular material P. Are sequentially detected. The detected distance is stored in the memory of the computer 19. The computer 19 obtains a function of a straight line approximating a locus composed of these points in the same procedure as described above, calculates an inclination angle of the straight line with respect to a horizontal plane, and stores the inclination angle in a memory.

Next, the computer 19 moves the sensor 16 by a predetermined distance in the longitudinal direction of the spatula 26, then moves the sensor 16 vertically upward, and inclines the free surface of the granular material layer P in the same procedure as described above. Calculate the angle and store it in memory. Further, the computer 19 has the sensor 1
6 is moved by a predetermined distance in the longitudinal direction of the spatula 26, and the sensor 16 is moved vertically downward to calculate the inclination angle of the free surface of the granular material layer P.

The computer 19 calculates the average value of the inclination angles obtained in the respective steps, and displays the average value on the display unit as the spatula angle before collapse. The measurer registers this angle in the memory using the operation keys. The measurement of the inclination angle may be performed at one point. However, if the inclination angles at a plurality of points are measured and the average value is determined as described above, the accuracy of the measurement value is improved.

Next, the measurer lifts the weight 27 to the upper end of the pole 25 and drops it, and performs an operation of giving a shock to the spatula 26 once. As a result, the granular material layer P deposited on the spatula 26 collapses, and its free surface exhibits a smaller inclination angle. Then, when an instruction to start measurement is input by the operation keys, the inclination angles of the three points of the granular material layer P are measured in the same procedure as described above, and displayed on the display unit as the spatula angle after collapse.

When this inclination angle is registered by the operation keys, the average value of the spatula angle before collapse and the spatula angle after collapse is calculated and displayed on the display unit.

FIG. 8 is a graph showing the results of measuring the spatula angle a plurality of times for various powders without changing the deposition state. The eight types are standard samples defined by JIS standards based on the granules obtained from the Kanto loam layer. From this graph, it can be seen that there is little variation in the measured values and almost constant results are obtained.

As a configuration for measuring physical properties other than the angle of repose and the spatula angle in the measuring apparatus 1, a known configuration is employed, and the specific contents and the method of use are omitted. I do.

Next, another embodiment of the present invention will be described. In this embodiment, as shown in FIG.
6 is the granular material layer P deposited on the repose angle measuring table 13
, And emits a light beam vertically downward to detect a distance from a spot light irradiated on the free surface of the granular material layer P. The computer 19 sends the sensor 16 to the vertex T. Move horizontally in the vertical plane including P,
A predetermined interval ΔX in the horizontal direction along the ridge line R1 of the granular material layer P
In the same procedure as above, calculate the distance between a plurality of points arranged in a row, find the function of a straight line approximating the trajectory obtained from these points, calculate the inclination angle of this straight line with respect to the horizontal plane, The inclination angle of the free surface of the granular material layer P is stored in the memory. Also, the same process is performed on the vertex T. The calculation is also performed on the other side of P, and the inclination angle of a straight line approximating a trajectory composed of a plurality of points arranged along the ridge line R2 with respect to the horizontal plane is calculated and stored in the memory. And computer 1
9 calculates the average value of the inclination angles obtained in each step, and displays this on the display unit as the inclination angle of the granular material layer P.

The measurement of the inclination angle may be performed only on one side of the vertex of the granular material layer. However, when the inclination angles on both sides of the vertex are calculated and the average value is calculated, the measurement is performed as follows. The accuracy is improved.

It should be noted that the present invention is not limited to the above embodiment, and can be implemented in various modes within the scope of the matters described in the claims.

[0045]

As described above, according to the present invention, a function of a straight line approximating a locus consisting of a plurality of points on the free surface of the granular material layer is obtained, and the inclination angle of this straight line with respect to the horizontal plane is calculated. By doing so, the inclination angle is calculated based on a fixed reference, so that there is no variation in the measured values due to the habit peculiar to the measurer. Further, there is no need for complicated work such as applying a protractor along the free surface of the granular material layer, and the labor and time required for measurement can be reduced.

According to the third, fifth, eighth and tenth aspects, the measurement accuracy is improved by obtaining the inclination angles at a plurality of locations and calculating the average value.

[Brief description of the drawings]

FIG. 1 is a front view of a measuring device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a sensor structure and a measurement principle.

FIG. 3 is an explanatory view of a measuring method by the measuring device of FIG. 1;

FIG. 4 is a front view of a shocker used in the measuring device of FIG. 1;

FIG. 5 is a side view of a spatula angle measuring unit used in the measuring device of FIG. 1;

FIG. 6 is a graph showing a trajectory formed by a point having a minimum distance from a sensor.

FIG. 7 is a graph showing the measurement results of the angle of repose of various granular materials.

FIG. 8 is a graph showing measurement results of spatula angles of various powders and granules.

FIG. 9 is an explanatory view of another embodiment of the present invention.

[Explanation of symbols]

 16 Sensor 18 Actuator (moving means) 19 Computer (control means) 26 Spatula P Powder layer

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-229901 (JP, A) JP-A-5-107171 (JP, A) JP-A-5-249021 (JP, A) Tadami Hanakawa, Hiroshi Yokoyama , Susumu Yamaguchi, "Development of Next-Generation Powder Tester", Proceedings of the 14th Symposium on Pharmaceutical and Particle Design, Powder Technology Society, Subcommittee on Pharmaceutical and Particle Design, October 15, 1997, pp. 51-54, pp. 51-54, Shuji Sasabe , “New Powder Tester PT-R”, Powder and Industry, Powder and Industry, February 1, 1998, Vol. 56-57 (97 Powder Industry Exhibition, Osaka Product Technology Briefing, November 14, 1997) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 11/00-13 / 04 G01B 11/00-11/30 JICST file (JOIS)

Claims (10)

(57) [Claims] 1. A sensor for emitting a light beam and detecting a distance from a point irradiated with the light beam to a side of the powdery or granular material layer deposited in a conical shape on a horizontal plane. It is arranged so that the optical axis of the light beam is horizontal while facing the free surface of the granular layer, and the sensor is moved in a horizontal direction perpendicular to the optical axis to move the sensor on the free surface along the movement path of the sensor. Performing the step of detecting a distance between a plurality of points arranged in a line from one end side to the other end side in the horizontal direction along the opposing line a plurality of times by moving the sensor a predetermined distance in the vertical direction a plurality of times; Extracting a point having a minimum distance from the sensor in each step, obtaining a function of a straight line approximating a trajectory formed by these points by a least square method, and calculating an inclination angle of the straight line with respect to a horizontal plane. Free table of sedimentary particulate layers A method for measuring the angle of inclination of a surface. 2. A sensor that emits a light beam and detects a distance from a point irradiated with the light beam, and a sensor that detects a distance from a point irradiated with the light beam, is provided above the particle layer deposited in a conical shape on a horizontal plane. The sensor is disposed so as to face the free surface of the body layer so that the optical axis of the light beam is vertical, and the sensor is moved horizontally in a vertical plane including the apex of the body layer to form the body layer. The distance between a plurality of points arranged at predetermined intervals in the horizontal direction along the ridgeline is detected, a function of a straight line approximating a trajectory composed of these points is obtained by the least square method, and the straight line A method for measuring an inclination angle of a free surface of a granular material layer in a deposited state, wherein the inclination angle is calculated. 3. The method according to claim 1, wherein the sensor is moved horizontally in the vertical plane to detect a distance between a plurality of points arranged at predetermined intervals in a horizontal direction along a ridge line of the granular material layer, A function of a straight line approximating a locus composed of these points is obtained by the least squares method, and a step of calculating an inclination angle of the straight line with respect to a horizontal plane is performed on both sides of the vertex of the granular material layer. The method according to claim 2, wherein an average value of the inclination angles is calculated. 4. A sensor for emitting a light beam and detecting a distance from a point irradiated with the light beam to a side of the granular material layer deposited on a horizontally supported spatula, the light beam emitting port is provided. It is arranged so that the optical axis of the light beam is horizontal while facing the free surface of the granular material layer, and the sensor is moved in the vertical direction to a line facing the movement path of the sensor on the free surface. The distance between a plurality of points arranged at predetermined intervals along the vertical direction is detected along, a function of a straight line approximating a locus composed of these points is obtained by the least square method, and the inclination angle of the straight line with respect to the horizontal plane is calculated. A method for measuring an inclination angle of a free surface of a particulate layer in a deposited state, which is characterized by being calculated. 5. The sensor is moved in a vertical direction to detect a distance between a plurality of points arranged on the free surface at predetermined intervals in a vertical direction along a line facing a movement path of the sensor. Then, a function of a straight line approximating a locus composed of these points is obtained by a least square method, and a step of calculating an inclination angle of the straight line with respect to a horizontal plane is performed at a plurality of locations by moving the sensor in the longitudinal direction of the spatula. 5. The measuring method according to claim 4, wherein an average value of the inclination angles obtained in the respective steps is calculated. 6. A light beam emitted horizontally in a horizontal direction toward a free surface of the granular material layer, which is disposed beside the horizontal surface and the granular material layer which is conically deposited on the horizontal surface. A sensor for detecting the distance to the point, moving means for moving the sensor in a horizontal direction and a vertical direction orthogonal to the optical axis of the light beam, and controlling the sensor and the moving means to move the sensor in the horizontal direction. Detecting a distance between a plurality of points arranged in a line from one end to the other end in the horizontal direction along a line facing the movement path of the sensor on the free surface of the granular material layer Is performed a plurality of times by moving the sensor by a predetermined distance in the vertical direction, extracting points at which the distance from the sensor in each step is the minimum, and using a least squares method to calculate a function of a straight line approximating a locus formed by these points. And the inclination of the straight line to the horizontal plane A measuring device for measuring an inclination angle of a free surface of a granular material layer in a deposited state, comprising a control means for calculating an angle. 7. A light beam which is arranged above a horizontal plane and a granular material layer which is conically deposited on the horizontal surface and is emitted in a vertical direction toward a free surface of the granular material layer, and is irradiated with the light beam. A sensor for detecting a distance from a point, a moving unit for moving the sensor in a horizontal direction in a vertical plane including a vertex of the granular material layer, and controlling the sensor and the moving unit to move the sensor in a horizontal direction. The distance is detected between a plurality of points arranged at predetermined intervals in the horizontal direction along the ridge line of the granular material layer by moving, and a function of a straight line approximating a locus composed of these points is determined by the least square method. And a control means for calculating an inclination angle of the straight line with respect to a horizontal plane, wherein the inclination angle of the free surface of the granular material layer in a deposition state is provided. 8. The control means moves the sensor in a horizontal direction in the vertical plane, and controls a plurality of points arranged at predetermined intervals in a horizontal direction along a ridge line of the granular material layer. Calculate the distance, find the function of a straight line approximating the locus consisting of these points by the least squares method, perform the step of calculating the inclination angle of the straight line with respect to the horizontal plane, on both sides of the vertex of the granular material layer, The measuring device according to claim 7, wherein an average value of the inclination angles obtained in the step is calculated. 9. A spatula supported horizontally, and a light beam emitted in a horizontal direction toward a free surface of the granule layer disposed on a side of the granule layer deposited on the spatula, and the light beam is emitted. A sensor for detecting a distance from an irradiated point, a moving unit for moving the sensor in a vertical direction, and a sensor for moving the sensor in the vertical direction by controlling the sensor and the moving unit to move the sensor on the free surface. Detects the distance between a plurality of points arranged at predetermined intervals in the vertical direction along a line facing the movement path of, and obtains a function of a straight line approximating a locus composed of these points by the least square method, Control means for calculating an inclination angle of the straight line with respect to a horizontal plane. An apparatus for measuring an inclination angle of a free surface of a granular material layer in a deposited state. 10. The moving means is capable of moving the sensor in a longitudinal direction of the spatula, and the control means comprises:
By moving the sensor in the vertical direction, the positions of a plurality of points arranged at predetermined intervals in the vertical direction along a line facing the movement path of the sensor on the free surface are detected, and from these points The step of calculating the inclination angle of the obtained straight line with respect to the horizontal plane by the least square method is performed at a plurality of locations by moving the sensor in the longitudinal direction of the spatula, and the average value of the inclination angles obtained in each of the steps is calculated. The measuring device according to claim 9, wherein: