JPH05340783A - Instrument and method for measuring stored quantity in silo - Google Patents

Abstract

PURPOSE:To accurately measure the quantity of aggregate stored in a silo by carrying a level gauge to a plurality of measuring points along a track and calculating the total volume of the aggregate from the measured values of the heaped-up height, etc., of the aggregate obtained at each measuring point. CONSTITUTION:A level gauge 6 and carrying section 12 are controlled by means of a microcomputer 13 and the pulse signal of the section 12 is transmitted to a CPU 13b. The CPU 13b controls the section 12 so as to move and stop the section 12 to and at a prescribed measuring position. A measuring point for measuring the height of aggregate is set on a track by previously stopping the gauge 6 at the point by using a keyboard 15 and CRT 14. The CPU 13b calculates the distance between each measuring point and the center of a silo. The section 12 is moved to all measuring points and the gauge 6 measures the height of the aggregate at each measuring point and stores the measured values in a memory 13c. The total volume of the aggregate stored in the silo is found from the heights of the aggregate and previously found distances.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an asphalt plant, a concrete plant, etc., and a silo storage for storing and supplying aggregates such as coarse sand, lime, and sandstone, which are raw materials used in each plant, for each type. The present invention relates to a quantity measuring device and a measuring method using the same.

[0002]

2. Description of the Related Art FIGS. 13 and 14 are a sectional view and a top view of a conventional storage amount measuring apparatus for silos for asphalt plants. Sand 2, for example, is stored as an aggregate in a cylindrical silo 1. This type of silo generally has a diameter of 3 to 10 m and a height of 10 to 20 m. The sand 2 is appropriately taken out from a discharge port 3 provided below the silo 1 via a belt feeder (not shown). The sand 2 is supplied into the silo 1 by the belt conveyor 5 provided above. At this time, it is necessary to constantly grasp the storage amount of the sand in the silo 1 and appropriately supply the sand so that the storage amount of the sand in the silo 1 is secured at a certain amount or more. For that purpose, it is necessary to monitor the amount of sand stored in the silo 1.
For this reason, it is not preferable in terms of safety and work efficiency that an operator or the like climbs up the silo 1 and monitors it. Therefore, a known level meter 6 using ultrasonic waves or the like is installed above the silo 1. When the sand 2 is discharged from the discharge port 3, ideally a substantially conical sand surface as shown on the surface 2a is formed. In order to determine the amount of sand 2 having this conical surface 2a, the level meter 6 is provided with the center point 1a of the silo and the inner wall surface of the silo 1.
It is provided at a 2: 1 point on a virtual line 1 connecting 1b. From this point, the level meter 6 measures the distance h ₁ to the surface 2a of the sand 2, and the distance h ′ ₂ (usually about 10 to 20 m to the bottom 1c of the silo 1 which is stored in the level meter 6 in advance and stored in memory. )
The difference _{h '2 -h' 1 = h} '3 and transmits as the height of the sand. The volume V of sand 2 from the radius r of the height h _'3 and Silo 1/3 · π · r ² ·
h 'is calculated by the _third formula.

[0003]

As described above, the discharge port 3 is provided.
Since the conical surface 2a is generally formed when is provided in the center of the silo 1, even if the height of only one point of the sand surface 2a is measured as described above, The volume of the entire sand 2 can be calculated accurately. However, by providing two outlets in the silo 1 like the outlets 3, 3 shown in FIGS. 15 and 16, sand may be supplied more efficiently. In this case, the sand surfaces 2b and 2c do not have a conical shape as shown in FIGS. 15 and 16. Therefore, as shown in FIG. 13 above, when the volume of the entire sand 2 is obtained from the measured value of the height of only one point on the surface of the sand as described above, the error from the actual value becomes very large. was there. As a solution to such a problem, an attempt has been made to reduce the error by arranging about four level meters in one silo and obtaining the volume of the entire sand from the measured values,
It was difficult to install too many level meters because the level meters were expensive and the installation space on the silo was limited.

The present invention has been made in order to solve the above problems, and an economical silo for accurately measuring the amount of aggregate stored in a silo without using many level meters. It is an object to provide a storage amount measuring device and a measuring method.

[0005]

A storage amount measuring device for silo according to the present invention is a track provided substantially horizontally on an upper portion of a cylindrical silo for storing aggregates, and a plurality of selected tracks on the track. Transporting means for transporting the level meter to an arbitrary measurement point, control means for controlling movement / stop of the transporting means and execution / stop of measurement of the level meter, deposition height of aggregate at each measurement point of the level meter Storage means for storing the measured value of the height, on the horizontal plane where the orbit exists, aggregates are formed at substantially the same height vertically below the section area equidistant in the horizontal direction from the center point of the silo. Based on the measurement of aggregate height at each measurement point and the distance from the center point of the silo to each measurement point under the assumption that they are accumulated, the same distance from the center point to each measurement point Corresponding to the thin skin of cylindrical shape of predetermined thickness Calculate the total volume of aggregate stored in the silo by calculating the volume of the aggregate for each of the above distances and calculating the sum of them, and calculate the total weight of the aggregate from that value. To have. The method for measuring the amount of stored silo according to the present invention is a method for measuring the amount of stored aggregate stored in a cylindrical silo for storing aggregate using a level meter, in which the upper track of the silo and the track Conveyance means for conveying the level meter to a plurality of arbitrary measurement points (measurement points from 1 to n) and control means for controlling the movement / stop of the conveyance means and the measurement of the level meter are provided, and (1) m Step for determining whether or not the level meter has been transported to the second measurement point, step S _{3 in} the flow of FIG. 5, (2) Stop the transport means when it is determined that the level meter has been transported to the mth measurement point Then, operate the level meter to measure the height of the aggregate existing vertically below the measurement point, (3) (1) to (2)
The step of (1) is repeated from m = 1 to m = n, and the measured value of the height of the aggregate at each measurement point is stored in the storage means. (4) On the horizontal plane where the track exists, the center point of the silo Based on the assumption that aggregates are deposited at substantially the same height vertically below the section area that is equidistant in the horizontal direction from the Based on the value and the distance from the center point of the silo to each measurement point, the aggregate volume corresponding to the portion of the cylindrical outer skin shape of a predetermined thickness that is thin and equidistant from the center point to each measurement point And calculating the total volume of the aggregates stored in the silo and calculating the total weight of the aggregates from the calculated value.

[0006]

In the silo storage amount measuring device and measuring method according to the present invention, the level gauge is conveyed to a plurality of measuring points on the track by the conveying means, and the measured value of the aggregate height at each measuring point is obtained. Based on the assumption that aggregates are deposited at substantially the same height vertically below the section area that is horizontally equidistant from the center of the silo on the horizontal plane where the orbit exists. , Based on the measured value of the accumulated height of aggregate at each measurement point and the distance from the center point of the silo to each measurement point, the outer shell of a thin cylinder of a predetermined thickness equidistant from the center point to each measurement point The volume of aggregate corresponding to the part of the shape is calculated for each of the above distances, the sum of them is calculated, and the total volume of the aggregate stored in the silo is calculated. Calculate the total weight of the material.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a storage amount measuring device for silo of the present invention used in an asphalt plant. FIG. 2 is a top view of the storage amount measuring device of the silo. Cylindrical silo 1
Sand 2, for example, is stored as an aggregate. The sand 2 is appropriately taken out from a discharge port 3 provided below the silo 1 through a known belt feeder (not shown). Also, sand 2
Is a silo 1 by means of a belt conveyor 5 provided above.
It is supplied to the central part. A track 11 made of, for example, H-shaped steel is provided above the silo 1. This orbit 11
A transfer unit 12 using a traveling mechanism of a known overhead crane traveling device travels on the top. Instead of an overhead crane, a level meter 6 is loaded on the transport section 12. The trajectory 11 is preferably as close to the center point 1a of the silo 1 as possible. However, the belt conveyor 5 is used so that the sand for supply can be supplied to the central point 1a.
Since it is difficult to install the track 11 so as to pass through the center point 1a, it is installed apart from the center point 1a by a dimension slightly larger than the width of the belt conveyor 5.

FIG. 3 shows a block diagram of the silo storage amount measuring device. The level meter 6 and the transport unit 12 are controlled by the microcomputer 13. The pulse signal generated by the pulse signal generation unit 12b of the motor 12 incorporated in the transport unit 12 is transmitted to the CPU 13b via the input / output interface 13a. By counting the number of pulse signals, the motor 12a is moved via the input / output interface 13a so that the transport unit 12 is moved to a predetermined measurement point position and stopped.
It is controlled by PU13b. Further, a CRT 14 which is a known microcomputer input / output device, a keyboard 15 and a printer 16 are CPs via an input / output interface 13a.
It is connected to U13b. The memory 13c stores a program for operating the CPU 13b, and a level meter 6
It also stores the data of the height of the sand at each measurement point, which is input via the A / D converter 13d and the input / output interface 13a.

Using the keyboard 15 and the CRT 14, the level meter 6 is stopped in advance and a measurement point Pm (m = 1 to n is a natural number) for measuring the height of sand is set on the track 11. It is preferable to set the measurement points at equal intervals, but there is no problem even if they are slightly deviated. Trajectory 11
In principle, it is shown as FIG. 4 on a horizontal plane including. Figure 4
Since the belt conveyor 5 is provided in order to supply sand to the center point 1a of the silo, the track 11 is provided in parallel with the belt conveyor 5 at a horizontal distance a from the center point 1a. (Because this figure is an explanatory diagram to show the principle,
11 is shown as a straight line. Since the track 11 is provided away from the belt conveyor 5 in this manner, sand or the like supplied by the belt conveyor 5 does not directly drop and the level meter 6 and the transport unit 12 are not damaged or soiled. .. Further, if an imaginary line that passes through the center point 1a and intersects the track 11 at right angles is denoted by Y, the horizontal plane by the imaginary line Y is a region on the right side (hereinafter referred to as a first region) Z _R and a region on the left side (hereinafter referred to as the It is divided into Z _L. Also, the virtual line Y and the trajectory
Let 11 be the point where 11 intersects, and let the horizontal distance between measurement point P _m and point M1 be
When d _m, CPU 13b from the data of the position for setting the horizontal distance d _m is the measurement point P _m is determined by calculation. Next, from the horizontal distance d _m and the above-mentioned distance a, the center point 1a of the measurement point P _m
The distance r _{m from} is calculated as the square root of (d _m ² + a ² ), thus the distance r ₁ ~ from the center point 1a of each measurement point P ₁ ~ P _n
r _n is required. The distance from the center point 1a to the inner wall surface of the silo 1 is r ₀ . Further, FIG. 5 shows a flow chart for carrying out the measurement by moving the level meter 6 to each of the measurement points P _m (P ₁ to P _n ) by the carrying section 12. In steps S2 to S4, the transport unit 12 moves to the predetermined measurement point P _m and stops. Next, in step S5, the height h _{m of the} sand is measured, and the measured value is stored in the memory 13c. Repeat these steps from m = 1 to n. According to this flowchart, P ₁
To P _n, the heights h ₁ to h _n of the sand vertically below the respective points are measured and stored in the memory 13c.

The height h of the sand obtained as described above₁~ H_n
And distance r₁~ R_nCalculate the volume of sand in the silo from. Less than
The outline of the concept at that time will be explained with reference to FIG.
It The horizontal distance from the center point 1a is the measurement point P₁Distance r equivalent to₁
Of the sand vertically below the horizontal plane and its vicinity.
Height is measuring point P₁The first area Z where_RSubstantially within
Are assumed to be the same. In other words, the shaded area in Figure 4
Area W₁Like the outer skin of a thin cylinder with a certain thickness vertically below
The height of the sand in the shape of the h is on average h₁Is that
is there. Therefore, the section area W₁The sand of that shape vertically below
The volume of V₁Then V₁= 1/2 ・ π (r₀ ²-r₁ ²) ・ H₁Represented
Be done. (Step S1 of FIG. 6 showing a flowchart described later
Equivalent to 2. ) Below, under the same assumption, the measurement point P_mBy
Section area W_mA thin cylinder with a predetermined thickness vertically below
The volume of sand in the shape of the outer skin of V_mThen V_m= 1
/ 2 ・ π (r_m-1²-r_m ²) ・ H_mIs expressed as (Float described below
6 corresponds to step S16 of FIG. ) As well
Measuring point P_mFirst zone Z of_RThe leftmost point P in_{m '}And point 1a
Section area W between m_'V of the volume of sand in the vertically lower part of_{m '}When
Then V_{m '}= 1/2 ・ (πr_{m '} ²・ H_{m '}). (See below
This corresponds to step S18 of FIG. 6 showing a row chart. )
Similarly, point P_mSecond zone of Z_LThe rightmost point P in_{m '+ 1}
Section W between point 1a and point 1a m_'+1Body vertically below the sand
The product is V_{m '+ 1}Then V_{m '+ 1}= 1/2 ・ πr_{m '+ 1} ²・ H_{m '+ 1}Is represented
Be done. (Step S2 of FIG. 7 showing a flow chart described later
Equivalent to 0. This section area W_{m '+ 1}Is the section area
W_{m '}Since there is a symmetric relationship with respect to the imaginary line Y in FIG.
However, the display is omitted. ) Similarly, the second zone Z_LOf
Section area W of_{m "}A thin cylindrical outer skin vertically below
The volume of sand in the shape of_{m "}Then V_{m "}= 1/2
π (r_{m "+1} ²-r_{m "} ²) ・ H_{m "}Is expressed as (Floater described later
7 corresponds to step S23 in FIG. Also this ward
Area W_{m "}Is the above-mentioned section area W_mAnd symmetric about the imaginary line Y
Therefore, the display is omitted in FIG.
It ) Similarly, the second area Z of the measurement points Pm_LThe leftmost of
Point P_{m "'}Section area W determined by_{m "'}Vertically below the thin place
V of the volume of sand in the shape of the outer shell of a constant thickness cylinder_m"_'
Then V_{m "'}= 1/2 ・ π (r₀ ²-r_{m "'} ²) ・ H_{m "'}Is expressed as
(Step S24 of FIG. 7 showing a flow chart described later
Hit This section area W_{m "'}Is the above-mentioned section area W₁And provisional
Since there is a symmetric relationship with respect to the ideal line Y, the table in FIG.
The illustration is omitted. ) Finally obtained as above
Each section area W_mThe total volume V of sand in the part corresponding to_SUMTo
Ask. (Steps in FIG. 7 showing a flow chart described later
Equivalent to S25. ) As described above, all of the sand in the silo is
Flow charts for obtaining the volume are shown in FIGS. 6 to 8.
The total weight is obtained by multiplying this total volume by the specific gravity of sand. Na
This flow chart is for when n ≧ 3
Measuring point P_mEven if it is not set on the virtual line Y
It The amount of sand stored thus obtained is shown in FIG.
To display on the screen of CRT14. Monitor this display
Or the minimum protection set to a certain value.
A sequence such as issuing an alarm when the pipe volume falls below
By incorporating it into the program, workers can quickly
Supply sand. Therefore, the storage amount of sand in silo 1 is always
More than a certain amount is secured.

Further, as can be seen from the above flow chart, the larger the value of n, the more accurate the volume of sand is required. In reality, however, each measuring point P _m measured by the level meter 6
Since the ultrasonic beam spreads vertically below, the height of the sand with respect to the width of about 1 m will be measured in some cases. Therefore, set the distance between the measurement points P _m to 1 m or less. However, the accuracy cannot be improved so much. It is possible to obtain a more accurate storage amount of sand by increasing the number of areas Z _R etc. and performing measurements in more areas, but since the level meter transportation method becomes more complicated, It is realistic to divide into regions Z _R and Z _L.

In the above embodiment, an example in which one level meter 6 is provided for one tank 1 has been described.
As shown in FIG. 10, two level meters 6 can be used to measure the storage amount of aggregates such as sand, lime and sandstone stored in each of the eight tanks. By using such a structure, for example, 8 to 10 tanks are required.
Only one level meter in one asphalt plant can accurately measure the amount of aggregate stored in each tank. An example of a CRT screen showing the storage amount of aggregate in such a plant is shown in FIG.

The maximum angle among the angles α as shown in FIG. 12 is generally called the angle of repose. This angle is about 60 ° for sand, although it depends on the type of aggregate. For example, when an attempt is made to measure a slope portion having a large angle of repose by the level meter 6 using ultrasonic waves as shown in FIG. 12, the ultrasonic waves may not be reflected in the direction of the level meter 6 and measurement may be impossible.
Since such a measurement point is likely to occur at the upper part of the discharge port 3,
It is desirable to exclude the upper part of the discharge port 3 from the measurement point in advance. Also, if there is a measurement point that cannot be measured due to a large angle of repose during the actual measurement, it is judged that the measurement point is shifted to the adjacent measurable measurement point side. It is desirable to add the flowchart of the subroutine for performing the measurement again to the flowchart of FIG.

[0014]

In the silo storage amount measuring apparatus and measuring method according to the present invention, the level meter is conveyed to a plurality of measuring points on the track by the conveying means, and the measured value of the height of the accumulated aggregate at each measuring point is measured. can get. On the horizontal plane where the orbit exists, it is assumed that aggregates of substantially the same height are deposited vertically below the section area equidistant from the center of the silo at each measurement point. Based on the measurement value of the accumulated height of the aggregate and the distance from the center point of the silo to each measurement point, a part of the shape of a thin cylindrical outer skin equidistant from the center point to each measurement point. The volume of aggregate corresponding to is calculated for each distance, the sum of them is calculated, the total volume of the aggregate stored in the silo is calculated, and the total weight is calculated from the value. Therefore, the amount of aggregate stored in the silo can be accurately measured, and since only one level meter is used, the structure is simple and economical.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a silo storage amount measuring device of the present invention.

FIG. 2 is a top view of the storage amount measuring device for the silo shown in FIG.

FIG. 3 is a block diagram of a storage amount measuring device for silos of the present invention.

FIG. 4 is a diagram showing in principle the positional relationship of measurement points P _m .

FIG. 5 is a diagram showing a flowchart for performing measurement by moving a level meter to each measurement point by a transport unit.

FIG. 6 is the first half of the flowchart for determining the volume of sand corresponding to each measurement point.

FIG. 7 is the second half of the flowchart for obtaining the volume of sand corresponding to each measurement point.

FIG. 8 is a diagram showing a mutual relationship between FIGS. 6 and 7;

FIG. 9 is an example of a CRT screen showing the amount of sand stored in a silo.

FIG. 10 is a diagram showing an example in which the storage amount measuring device for silo of the present invention is applied to an actual asphalt plant.

11 is an example of a CRT screen showing the amount of sand stored in a silo in the asphalt plant shown in FIG.

FIG. 12 is a diagram showing a state of repose angle.

FIG. 13 is an example of a cross-sectional view of a conventional storage amount measuring device for silos.

FIG. 14 is a top view of a conventional storage amount measuring device for silos.

FIG. 15 is an example of a cross-sectional view of a conventional storage amount measuring device for silos.

FIG. 16 is an example of a cross-sectional view of a conventional storage amount measuring device for silos.

[Explanation of symbols]

 1 Silo 2 Sand 6 Level meter 11 Orbit 12 Transport section 13 Microcomputer 13b CPU 13c Memory

Claims (4)

[Claims] 1. A track provided substantially horizontally on an upper portion of a cylindrical silo for storing aggregates, a transfer means for transferring a level meter to a plurality of arbitrary measurement points selected on the track, Control means for controlling movement / stop of the transportation means and execution / stop of measurement of the level meter, storage means for storing measured values of aggregate height at each measurement point of the level meter, horizontal position where the track exists On the plane, aggregates are deposited at substantially the same height vertically below the section area that is equidistant in the horizontal direction from the center point of the silo, at each measurement point. Based on the measurement value of the pile height of the aggregate and the distance from the center point of the silo to each measurement point, it corresponds to the portion of the shape of a thin cylindrical outer skin equidistant from the center point to each measurement point. Calculate the volume of aggregate for each of the above distances,
A storage amount measuring device for silos, comprising: an arithmetic means for calculating the total volume of aggregates stored in the silo by calculating the sum of them and calculating the total weight of the aggregates from the total volume. 2. On a horizontal plane where the orbit exists,
When the horizontal plane is divided into first and second regions by a line that passes through the center point of the silo and intersects perpendicularly with the orbit, vertically below the section region that is equidistant in the horizontal direction from the center point of the silo. Assuming that aggregates of substantially the same height are accumulated in each area, it is assumed that each area has a thin predetermined thickness equidistant from each measurement point and the center point. The volume of aggregate that corresponds to the portion of the outer shell of the cylinder is calculated for each of the above distances, and the total volume of the aggregate stored in the silo is calculated by calculating the sum of these, and from that value The silo storage amount measuring device according to claim 1, wherein a total weight is calculated. 3. A method for measuring the storage amount of aggregate stored in a cylindrical silo for storing aggregate using a level meter, wherein a track at an upper part of the silo and a plurality of arbitrary measurement points on the track. (1) n-th measurement point, a conveyance means for conveying the level meter and a control means for controlling the movement / stop of the conveyance means and the measurement of the level meter are provided, and (1) the level is measured at the m-th measurement point. Step for determining whether or not the level meter has been transported, step S _{3 in} the flow of FIG. 5, (2) When it is determined that the level meter is transported to the m-th measurement point, the transportation means is stopped and the level meter is operated. Then, the step of measuring the height of the aggregate existing vertically below the measurement point, (3) The steps of (1) to (2) above are repeated from m = 1 to m = n to measure the aggregate at each measurement point. Storing the measured value of the height in a storage means, (4) the horizontal plane where the orbit exists. On the surface, under the assumption that aggregates are deposited at substantially the same height vertically below the section area that is equidistant in the horizontal direction from the center point of the silo, at each measurement point Based on the measurement value of the pile height of the aggregate and the distance from the center point of the silo to each measurement point, it corresponds to the portion of the shape of a thin cylindrical outer skin equidistant from the center point to each measurement point. The aggregate volume of the aggregates stored in the silo is calculated by calculating the aggregate volume for each of the above distances, and the sum of them is calculated, and the total weight of the aggregates is calculated from that value. A method for measuring the storage amount of silos, which comprises: 4. In the step (4), on the horizontal plane where the track exists, the horizontal plane is divided into the first and second regions by a line that passes through the center point of the silo and intersects the track vertically. When divided, the aggregates that are vertically below the section area that is horizontally equidistant from the m-th measurement point and the center point of the silo are deposited at substantially the same height. Assuming that it is established within the region, the volume of aggregate corresponding to the part of the outer skin of the cylinder with a predetermined thickness that is equidistant is calculated for each of the above distances, and the sum of them is calculated to calculate the total inside of the silo. The method for measuring the storage amount of silos according to claim 3, wherein the step is a step of calculating the total volume of the aggregate stored in, and calculating the total weight of the aggregate from the value.