JPH02189441A - Method and apparatus for measuring surface moisture rate of aggregate - Google Patents

Abstract

PURPOSE:To measure the surface moisture rate of aggregate automatically in a short time in accordance with the measuring method based on the JIS by injecting water to a tubular part at the upper part of a measuring container, measuring the water level and the weight, and storing the measured data into a microcomputer. CONSTITUTION:An adequate amount of water is injected into a flask shaped measuring container 6 having a tubular part 8 and a storing part 9. The water level is increased to the vicinity of the lower part of the tubular part 8. The distance L1 between the water level and a distance sensor 12 and the weight W of the injected water are measured. Then, an adequate amount of aggregate which is a material to be measured is inputted into the measuring container 6. The total weight W2 of the water that is injected beforehand and the inputted aggregate is measured. The distance L2 between the water level and the distance sensor is also measured. The total area of the increased water level in the measuring container caused by the input of the aggregate is made to be SIGMAAi. The specific gravity of the water is made to be sigmaW. The surface dry specific gravity of the aggregate that is the material to be measured is made to be G. Then, the surface moisture rate is operated with a microcomputer based on the expression. Thus the surface moisture rate of the aggregate is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an aggregate surface water rate measuring method and apparatus for measuring the surface water rate of aggregates such as sand and gravel.

[Conventional technology] When ready-mixed concrete is manufactured using a batcher plant, concrete materials such as sand, gravel, cement, water, and admixtures are mixed in a fixed ratio.
It is known that the ratio of water amount to M has an important effect on concrete strength. Therefore, when measuring water according to the mix of concrete to be manufactured, it is necessary to take into account the surface water of the aggregate adhering to the surface of sand, gravel, etc.

Conventionally, there are methods using capacitance, infrared rays, neutron beams, etc. to measure the aggregate surface water percentage used to calculate the surface water content of the aggregate. Also, in JIS, JISA
ll11r Fine aggregate surface moisture test method J, JISA11
A measurement method based on 25 r-aggregate moisture content test method and surface water content test method based on moisture content is known.

[Problems to be Solved by the Invention] However, in many devices that measure surface water percentage using capacitance, infrared rays, neutron beams, etc., the detector is brought into contact with aggregate, so Measurement accuracy decreases when materials adhere to the aggregate or the particle size and packing density of the aggregate change, and furthermore, in the case of aggregate containing salt, there is a large variation in the measured values, making it impossible to measure accurately. . In addition, the measuring device based on JIS has the disadvantage that it takes time to manually measure weight and capacity using experimental equipment, and cannot keep up with the cycle time of ready-mixed concrete production.

Therefore, in view of the above points, the present invention aims to increase the surface water content of aggregate by J
The purpose of the present invention is to propose a method and apparatus for measuring aggregate surface water content that can be automatically measured in a short time in compliance with the measurement method based on IS.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a flask-shaped measuring container having an upper opening and a lower opening, which is attached to a weight measuring means, and an opening is left in the lower opening of the measuring container. Along with installing an on-off valve that closes.

A distance sensor for measuring the water level in the weighing container is disposed above the upper opening, and a microcomputer is provided for calculating the surface water percentage of the aggregate by processing the data measured by the weight measuring means and the distance sensor. The present invention provides an aggregate surface water turbine measuring device characterized by the following.

[Function] In the aggregate surface water rate measuring device according to the present invention, first,
Pour an appropriate amount of water into a flask-shaped measuring container with the opening/closing valve at the bottom opening of the measuring container closed, and raise the water level to near the bottom of the cylindrical part with a constant inner diameter at the top of the measuring container. The water level is measured by a distance sensor, the weight is measured by a weight measuring means, and the measured data is input into a microcomputer.

Next, an appropriate amount of the sampled aggregate is gently placed into the measuring container. And after the bubbles diverge.

The weight is measured again by the weight measuring means, and the water level that has risen due to the input aggregate is again measured by the distance sensor, and the measured data is imported into the microcomputer.The microcomputer inputs the imported measurement data and preset settings. The surface horizontality of the aggregate is calculated by executing a surface water rate calculation program from the specific gravity of the water placed, the surface dry specific gravity of the aggregate, and the total area of the water level rising portion of the measuring container.

[Example] Embodiments of the present invention will be described below based on the drawings.

A main body 1 of a surface water rate measuring device for measuring the surface water rate of aggregate has its components housed in a frame 4 on a support member 3 disposed near the bottom of an aggregate storage tank 2 of a batcher plant. To explain its constituent devices one by one, a flask-shaped measuring container 6 fixed to a support stand 5 is attached to the lower part of the frame 4 via a load cell 7. The measuring container 6 consists of a cylindrical part 8 whose inner diameter has been machined so that the internal volume can be accurately determined if the height level is known, and a reservoir part 9 for storing the sample.

An abbreviated branch pipe 10 whose height is approximately equal to the height of the cylindrical part 8 and whose inner diameter is uniformly processed is connected to the side of the storage part 9. Further, an on-off valve 11 is attached to the lower part of the reservoir 9 to open and close the lower opening.

An ultrasonic sensor 12, which is a distance sensor, is fixed to the frame 4 located above the branch pipe 10, and the ultrasonic sensor 12 emits ultrasonic waves toward the water surface in the branch pipe 10, The water level in the measuring container 6 is measured by catching the ultrasonic waves reflected from the measuring container 6 and measuring the time from when they are emitted until they are reflected.

Note that the measuring container 6 shown in FIG. 1 is provided with a branch pipe 10 in order to be less susceptible to the effects of ripples on the water surface when measuring the water level with the ultrasonic sensor 12, but the structure of the measuring container 6 is simplified. In order to
An ultrasonic sensor 12 is provided above the cylindrical portion 8 of the cylindrical portion 8.
In addition, when installing the surface water turbine measuring device, use anti-seismic rubber or an anti-seismic mechanism to minimize the effects of vibrations from the batcher plant main body. It is preferable to do so.

A water storage tank 13 is provided above the measuring container 6, and water can be poured into the measuring container 6 through the water injection pipe 14 by opening and closing a valve 15 arranged on a water injection pipe 14 connected to the lower part of the water storage tank 13. .

An aggregate sampling device 16 is disposed from below the aggregate storage tank 2 to above the measuring container 6, and the aggregate sampling device 16 has a large number of sample collection packets 17 disposed at the front and rear of a frame 18. The sprocket 19 is attached to the sprocket 19 that is rotated, and the chain 21 is driven by the rotation of the motor 22. When discharging the aggregate from the lower part of the aggregate storage tank 2, the aggregate packet 17 collects the aggregate and stores it in the weighing container 6. It can be used as a sample. Note that this aggregate sampling device is not limited to the above-mentioned structure, and any device that can sample aggregate when discharging the aggregate from the aggregate storage tank 2 may be used.

23 indicates a microcomputer that performs arithmetic processing on various data. The microcomputer 23 is a CPU2
4 and a storage section 25, and A-D converters 26 and 27.
It is connected to the load cell '7 and the ultrasonic sensor 12 via the load cell 7 and the ultrasonic sensor 12, and is programmed to input data measured by the load cell 7 and the ultrasonic sensor 12 into the CPU 24 to calculate the aggregate surface water wheel. In addition, the specific gravity of water required to calculate the aggregate surface water turbine, the surface dry specific gravity of aggregate (aggregate in a dry state with no water absorbed inside the aggregate and no moisture attached to the surface) A setting input unit 28 for setting and inputting initial data such as specific gravity (specific gravity) and total cross-sectional area corresponding to the water level measurement position of the cylindrical part 8 of the measuring container 6 and the branch pipe 10, and a display device 29 for displaying processing results are connected. There is. Furthermore, it is also connected to an operation panel 30 so that the calculated aggregate surface water percentage can be fed back to the material metering of the plant.

Therefore, when measuring the surface water turbine of aggregate, the specific gravity W of water (when performing high-precision calculations taking into account the water temperature, the specific gravity W of the water is The corresponding specific gravity is usually 1 (g/
cc)), the surface dry specific gravity G of the aggregate, the cross section fiA1 (cm") of the cylindrical part 8 of the measuring container 6, and the cross-sectional area A2 of the branch pipe (
Enter the total area ΣA i (cm") in advance, then operate the on-off valve 11 at the bottom of the measuring container 6 to close the bottom opening, and open the water injection pipe 14 of the water storage tank 13. An appropriate amount of water is injected by controlling the opening and closing of the valve 15 to raise the water level to near the bottom of the cylindrical portion 8 of the measuring container 6.

After water injection, weight of water injected by load cell 7 W 1
At the same time as measuring (g), the ultrasonic sensor 12 emits ultrasonic waves toward the water surface in the branch pipe lO, measures the time until the reflected waves return from the water surface, and the ultrasonic sensor 12 to the water surface is calculated.

Measurement distance L 1 (c ■) = Measurement time Sound velocity / 2 Next, the aggregate is discharged from the aggregate storage tank 2, and the aggregate sampling device 1
Rotate the motor 22 of 6.

The pack 17 is moved while receiving and sampling the aggregates into a plurality of bulk buckets 1f, and the aggregates in the bulky buckets 1f are gently put into the weighing container 6 one after another.

After air bubbles in the aggregate are released, the total weight W2 of the water in the weighing container 6 and the loaded aggregate is measured by the load cell 7, and the ultrasonic sensor 12 measures the water level in the branch pipe 10 and the ultrasonic sensor 12. Measure the distance L2 (cm) from the At this time, the water level within the cylindrical portion 8 of the measuring container 6 and within the branch pipe 10 rises equally depending on the amount of aggregate introduced.

These measurement data are input into a microcomputer and the surface water percentage P ($) is calculated using a quintic equation.

The sampling aggregate BIrWs (g) is surface dry aggregate.

The amount of water vS(g) replaced with the sampling aggregate is the sum of the amount of water replaced with surface-dry sand and the amount of surface water. Since the surface water amount Ws is added to this equation, it becomes: At this time, Vs is the amount of change in the water level in the measuring container 6 (
Ll −L2 ), and Vs = (
Ll-L2)X (ΣAi)X9w.

Further, Ws can be determined from the difference between the measured weights W2 and Wl, and Ws = W2 - Wl. Therefore, the following equation is finally programmed into the microcomputer to calculate the surface water percentage P (X) of the aggregate.

P ($) = In this way, by measuring the difference in the water level in the measuring container 6 before and after charging the sampling aggregate, the surface water wheel of the aggregate can be easily calculated. Furthermore, although it is desirable that the amount of water injected into the measuring container 6 be a constant amount, since the water level is measured every time water is poured, it is not necessary to keep the amount constant, and the residual moisture in the measuring container 6 will also be included in the next measurement. It is easy to operate because it does not affect
This allows rapid and automatic measurements of surface water turbines.

When the measurement of the surface water content of the aggregate is completed, the on-off valve 11 at the bottom of the measuring container 6 is operated to open the lower opening and discharge the aggregate inside together with water. At this time, water injection pipe 1
It is preferable to pour water from 4 to wash the inside of the measuring container 6 and discharge the remaining aggregate.

[Effects of the Invention] As described above, in the method for measuring aggregate surface water content according to the present invention, it is possible to automatically measure the surface water content of aggregates using a calculation method based on JIS, and Since the surface water wheel of the material can be measured quickly, it is fully compatible with the production cycle of ready-mixed concrete.

Furthermore, since the water level in the measuring container 6 is measured every time the surface water percentage of the aggregate is measured, the surface water percentage can be accurately measured without being affected even if water remains in the measuring container 6. It is something that can be done.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway front view showing one embodiment of the aggregate surface water content measuring device according to the present invention, and Fig. 2 is another embodiment of a measuring container employed in the aggregate surface water percentage measuring device. FIG.

Claims (3)

[Claims] (1) Pour an appropriate amount of water into a flask-shaped measuring container that has a cylindrical part and a storage part, raise the water level to near the bottom of the cylindrical part, and calculate the distance L1 between the water surface and the distance sensor and the injected water. Then, an appropriate amount of aggregate, which is the object to be measured, is put into a measuring container, and the total weight W2 of the water poured earlier and the added aggregate is measured. Measure the distance L2 between the water surface and the distance sensor, and let ΣAi be the total area of the water surface that rises in the measuring container due to the input of aggregate, let the specific gravity of water be ρw, and let the surface dry specific gravity of the aggregate, which is the object to be measured, be G. , the following formula, [{(Li-L2)(ΣAi)(ρw)-(W2-W1
)/G}/{(W2-W1)-(Li-L2)(ΣAi
)(ρw)}]×100 by a microcomputer to obtain the surface water percentage of the aggregate. (2) A flask-shaped measuring container having an upper opening and a lower opening is attached to the weight measuring means, and an on-off valve for opening and closing the opening is provided at the lower opening of the measuring container, and a measuring container is provided above the upper opening. An aggregate characterized in that it is equipped with a distance sensor that measures the water level within the aggregate, and a microcomputer that calculates the surface water percentage of the aggregate by processing the data measured by the weight measuring means and the distance sensor. Surface water rate measuring device. (3) A flask-shaped measuring container having an upper opening and a lower opening is attached to the weight measuring means, and an on-off valve for opening and closing the opening is provided at the lower opening of the measuring container, and a shutoff valve is provided on the side of the measuring container. Approximately L-shaped branch pipes are connected, a distance sensor for measuring the water level in the branch pipe is arranged above the branch pipe, and the data measured by the weight measuring means and the distance sensor is processed to calculate the aggregate content. An aggregate surface water rate measuring device characterized by being equipped with a microcomputer that calculates the surface water rate.