JPH07113208A - Indicating method for storage amount in aggregate storage bin of asphalt plant - Google Patents

Abstract

PURPOSE:To more accurately indicate a storage level by automatically compensating a capacitance type level indicator even if the level indicator is influenced by the atmospheric variation of the inside of an aggregate storage bin. CONSTITUTION:A storage level-indicating value is operated by adding a correction factor R to an output value from a level sensor 10 mounted on each section of an aggregate storage bin 4 and is indicated on an indication part 16. The correction factor R is preset as a constant before the operation of a plant is started. However, during a time zone wherein an operation of discharging aggregates from the aggregate storage bin 4 is stopped and an operation of throwing aggregates into the aggregate storage bin 4 is stopped, i.e., while the operation of the plant is being discontinued, if the output value from the level sensor 10 is varied, the correction factor R is corrected responding to the rate of its variation and the storage level-indicating value is prevented from changing. After that, the storage level-indicating value is operated using a correction factor Rx corrected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for displaying a storage amount of an aggregate storage bin of an asphalt plant for producing an asphalt mixture which is a road paving material on a display device on a control panel.

[0002]

2. Description of the Related Art An aggregate storage bin for temporarily storing aggregate heated by a dryer is mounted on the upper part of a plant body of an asphalt plant, and a level meter for detecting a storage level is provided in the aggregate storage bin. is doing. As this level meter, a torque motor type level meter that detects the presence or absence of aggregate by the movement of rotary blades is generally used to detect the empty position and the full position in the aggregate storage bin. Target. Recently, it has become desirable to continuously display the storage level in the aggregate storage bin as the monitorability of the operation panel is improved. Capacitance-type level that enables continuous measurement of the storage level. There are cases where the total is adopted.

[0003]

However, when the storage level is measured by a capacitance level meter, there are many factors that affect the measurement, such as steam being generated from the heated aggregate in the aggregate storage bin. Yes, the level meter output such as zero point and span width adjusted at the start of operation may shift during operation, and it is necessary to perform zero point adjustment and span adjustment each time, and maintenance is very troublesome. is doing.

In view of the above points, the present invention provides an aggregate storage bin for an asphalt plant in which an accurate storage level is displayed as much as possible by correcting the level meter output even if it is affected by the atmosphere in the aggregate storage bin. It is an object of the present invention to provide a storage amount display method of.

[0005]

In order to achieve the above-mentioned object, the present invention provides a capacitance type level sensor in an aggregate storage bin of an asphalt plant for storing heated aggregate, and the level is The output value from the sensor is taken into the control unit every predetermined time, the storage level display value is calculated by adding the correction coefficient, and the storage level display value is output and displayed on the display unit, and the bone from the aggregate storage bin is also displayed. During the time period when the delivery of the material is stopped and the feeding of the aggregate into the aggregate storage bin is stopped, the output values before and after being taken in from the level sensor are compared, and the output values before and after that are varied. Occasionally, the fluctuation rate of the output value before and after was calculated, and the value of the correction coefficient was corrected according to the fluctuation rate so as not to change the storage level display value, and after that, the correction coefficient was changed to the previously set correction coefficient and corrected. Check the correction factor It is characterized in that to calculate the storage level display value by adding the output value of Rusensa.

[0006]

According to the present invention, the storage level display value is calculated by adding the correction coefficient to the value output from the capacitance type level sensor, and the correction coefficient is appropriately corrected during the plant operation. By doing so, the most accurate storage level is displayed.

As the correction coefficient, a constant is initialized in advance before the operation of the plant is started. Then, when the plant starts operating, the output value from the capacitance level sensor is taken into the control unit at every predetermined time, the storage level display value is calculated by adding the correction coefficient to the output value, and the storage level display value is calculated. Is displayed on the display.

During the plant operation, the level sensor is operated by the level sensor during the period when the discharging of the aggregate from the aggregate storage bin is stopped and the loading of the aggregate into the aggregate storage bin is stopped, that is, during the suspension of the shipment. The output values before and after the capture are compared and constantly checked for fluctuations. If the storage level, which should not have changed during shipment interruption, is fluctuating, it is considered that the level sensor is affected by the atmosphere in the aggregate storage bin, and the correction factor is set so that the storage level display value does not fluctuate. To fix. After that, the storage level is displayed by the corrected correction coefficient. In this way, the correction coefficient is appropriately corrected according to the change in the atmosphere in the aggregate storage bin to bring it closer to the more accurate storage level display.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic explanatory view showing a part of a plant body of an asphalt plant for producing an asphalt mixture, and 1 is a bucket elevator for lifting aggregate heated by a dryer 2 which is a heating device to the upper part of the plant body. Therefore, the lifted aggregate is supplied to the vibrating screen 3 through the supply chute 1a. The aggregate sieved by the vibrating sieve 3 is put into the aggregate storage bin 4 divided according to the particle size and stored. At the upper part of each compartment of the aggregate storage bin 4, an overflow pipe 5 is provided for overflowing excess aggregate and discharging it to the outside.

An aggregate discharge gate 6 is disposed below the aggregate storage bin 4, and an aggregate measuring tank 7 for measuring a predetermined amount of aggregate discharged from the discharge gate 6 is disposed below the aggregate storage bin 4. I have set up. A mixer 8 is arranged below the aggregate measuring tank 7,
The aggregate measured in the aggregate measuring tank 7, the asphalt measuring tank (not shown), the molten asphalt measured in the stone powder measuring tank, and the stone powder are added and mixed to prepare a desired asphalt mixture.

Supply chute 1a of bucket elevator 1
Is provided with a flow sensor 9 for detecting the flow of aggregate, and each compartment of the hot bin 4 is provided with a capacitance type level sensor 10 having a wire-like sensor portion. Further, the overflow pipe 5 is provided with an overflow sensor 11 for detecting the overflow of aggregate from the hot bottle 4.

Reference numeral 12 denotes a level display device that receives the output from the level sensor 10 and displays the level of the aggregate in the aggregate storage bin 4, and includes a control unit 13 that corrects and calculates the output value of the level sensor 10. In the center, an I / O unit 14 for receiving the output signal from the level sensor 10, an input unit 15 for inputting various data, a display unit 16 for outputting calculated display data, and a storage of the input data and the calculated data. It is composed of a storage unit 17 for storing.

Next, a method of displaying the storage level detected by the electrostatic capacity type level sensor 10 provided in the aggregate storage bin 4 on the display portion 16 of the level display device 12 will be described. The storage level is shown in%.

The output value from the level sensor 10 is C%, and the storage level display value displayed on the display unit 16 is Out.
%. Then, the correction coefficient R is related to these, and the storage level display value is calculated based on the following equation. Out = C / R × 100 (%) (1) It should be noted that the output value C% is a value output from the level sensor 10, for example, the voltage output when the space is empty is 0 mv, and the voltage output when the space is full is 10 mv. Is 0 as the storage level display
It is a value converted as a value of 100%. The correction coefficient R is a coefficient for correcting the phenomenon in which the output value C% deviates from the actual storage level due to a change in the atmosphere in the aggregate storage bin 4.

Next, a method of correcting the output value from the level sensor will be described with reference to the flow charts of FIGS. In the figure, S1 to S32 represent steps of each procedure.

FIG. 2 shows a procedure of initial setting before the start of operation of the plant. First, as an initial setting before the start of operation, the value of the correction coefficient R is input and set from the input unit 15 using, for example, 100 as a reference value. (S1).

Next, the empty amount of the aggregate storage bin 4 is confirmed, and the zero point adjusting function of the level sensor 10 is operated to set the output value C output from the level sensor 10 to zero%. Then, the control unit 13 outputs the output value C = 0 based on the equation (1).
From%, the storage level display value Out = 0% is calculated,
The zero point of each sensor is adjusted so that the storage level display value Out on the display unit 16 becomes zero% (S2).

When the zero point of the level sensor 10 is determined by the zero point adjustment, the aggregate is put into the aggregate storage bin 4 to the full amount, and the span adjusting function of the level sensor 10 is operated to operate the level sensor. Output value C from 10 is 10
Adjust to 0% and set C = R. Then, the control unit 13 sets C = R% and calculates the equation (1) to set the storage level display value Out to the display unit 16 to 100%.
Then, the storage level display value Out is used as the span width of the level display to perform the span adjustment of the level sensor (S3).

Once the zero point adjustment and span adjustment operations have been completed, it is determined whether or not the initial settings are to be completed, and if the adjustment is to be continued, the process returns to step S1 and the above operations are repeated. When ending, the process goes to END and ends.

Next, when the operation is started, as shown in FIG. 3, the output value C from the level sensor 10 is taken into the level display device 12 every predetermined time (S5). The control unit 13 uses R = 100 as the correction coefficient based on the equation (1).
To calculate the storage level display value Out (S
6) The output display on the display unit 16 is started (S7). If the aggregate storage bin 4 is empty immediately after the start of operation, the output value C from the level sensor 10 is 0%, so the storage level display value Out is also 0%, and the display unit 16 displays 0%.
Is displayed.

When the loading of aggregate into the aggregate storage bin 4 is started (S8) and the output value C from the level sensor 10 begins to rise (S9), the storage level display value Out of the calculation result also rises. The storage level display value Out is sequentially displayed on the display unit 16 (S10). The display on the display unit 16 may be digital display by numerical values, analog display such as a bar graph, or both of them.

When the aggregate is stored in the aggregate storage bin 4 and the asphalt mixture starts to be shipped, the situation of the aggregate delivery and the state of the aggregate input into the aggregate storage bin 4 will be checked. Sequentially detect to see if operation has been interrupted. Therefore, it is judged whether or not the discharging gate 6 is closed and the discharging of the aggregate is stopped (S11). If the discharging of the aggregate is stopped, then the flow sensor arranged on the supply chute 1a is determined. It is judged from the output of 9 whether or not the introduction of the aggregate into the aggregate storage bin 4 is stopped (S12), and if the introduction of the aggregate is also stopped, it means that the operation is suspended.

When the operation is interrupted, it means that the flow of aggregate in the aggregate storage bin 4 is stopped. During this period, the storage level display value should not fluctuate. Since the sensor 10 is affected by the atmosphere in the aggregate storage bin 4, it needs to be corrected. Therefore, of the output values C fetched from the level sensor 10 every predetermined time, the previous output value Cx and the current output value C
It is compared with y to check whether there is any change (S1
3). According to the comparison judgment (S14) as to whether the previous output value Cx = the present output value Cy (S14), if Cx = Cy is not satisfied, the storage level in the aggregate storage bin 4 does not actually change. Since the output value of the level sensor 10 is fluctuating, it is presumed that the level sensor 10 is affected by some influence and its electric output is displaced.

Therefore, if Cx = Cy is not satisfied, Cy / Cx is calculated in order to obtain the variation rate between the previous output value Cx and the current output value Cy (S15). Then, the electrical deviation of the output of the level sensor 10 is detected as the storage level display value Ou.
The correction coefficient R is modified so as not to reach t. The formula for obtaining the correction correction coefficient Rx is Rx = R × C
The corrected correction coefficient Rx is calculated by substituting the calculated Cy / Cx into y / Cx (S16). The corrected correction coefficient Rx thus obtained is used by replacing it with the correction coefficient used so far (S17).

If the aggregate payout is not stopped in step S11 or the aggregate feed is not stopped in step S12, the correction coefficient R is not corrected and the process proceeds to step S18. Step S1
If Cx = Cy in 4 and there is no variation between the previous output value Cx and the current output value Cy, it is determined that the electrical output of the level sensor 10 is not displaced, and the process also proceeds to step S18. In step S18, it is determined whether the operation is completed (S18), and if the operation is continued, the process returns to step S11 and the above procedure is repeated. When ending the operation, the process goes to END to end the operation.

In this way, during the suspension of shipping, the level sensor 1
The output values before and after being taken from 0 are compared to check if there is a change, and if the storage level, which should have not changed during shipment interruption, is changing, the atmosphere in the aggregate storage bin 4 will have an effect. The correction coefficient is modified so that the display of the storage level does not fluctuate because it is considered to have been received. In this way, the correction coefficient is appropriately corrected according to the change of the atmosphere in the aggregate storage bin to bring it closer to the more accurate storage level display.

The measurement of the storage level in the aggregate storage bin 4 and the correction of the correction coefficient R thereof in the steady state during the plant operation have been described above. Next, the aggregate in the aggregate storage bin 4 is full. Then, the correction of the correction coefficient R when the overflow pipe 5 overflows from the overflow pipe 5 or when the aggregate in the aggregate storage bin 4 becomes empty will be described with reference to the flowcharts of FIGS. 4 and 5.

FIG. 4 illustrates the case where the aggregate in the aggregate storage bin 4 overflows. Whether the overflow sensor 11 provided in the overflow pipe 5 detects the overflow of the aggregate during the plant operation. It is determined whether or not (S19). And the overflow sensor 11
If the company has detected an aggregate overflow, then the storage level must show 100%, so if 1
If it is 00% or more, it is necessary to correct the correction coefficient to an appropriate value and set the storage level display to 100%.

Therefore, the output value C of the level sensor 10 is compared with the correction coefficient R (S20), and the output value C is corrected by the correction coefficient R.
Or more, that is, whether C ≧ R is satisfied (S2
1) If C ≧ R and the output value C is equal to or more than the value of the correction coefficient R, the storage level display value Out calculated by the above equation (1) indicates an abnormal value of 100% or more. become. This is because the level sensor 10 has a difference in electrical output due to a change in the atmosphere at the measurement location, and the output is higher than the normal value. Therefore, the value of the correction coefficient R is output here. The storage level display value Out is corrected by replacing it with the output value C (S2).
2).

When the correction is completed, it is judged whether or not the operation is completed (S23). If the operation is continued, the process returns to step S19 to wait for overflow detection, and if the operation is completed, the process proceeds to END and is completed.

FIG. 5 illustrates the case where the aggregate in the aggregate storage bin 4 becomes empty, and it is determined whether the discharge gate 6 is open during the plant operation (S24). If the discharge gate 6 is open, it is then determined whether or not there is an output value C from the level sensor 10 (S25). Then, when the output value C is detected, the previous output value Cx and the current output value Cy are compared among the output values C taken in every predetermined time (S26).

Then, the previous output value Cx and the current output value are set to Cy.
It is judged whether or not there is an equal change (S27), and Cx
= Cy and when the previous output value Cx and the current output value Cy do not change, the current output value Cy and the correction coefficient R are further compared (S28), and the current output value Cy becomes less than or equal to the correction coefficient R. It is determined whether or not (S29), and if the current output value Cy is equal to or less than the correction coefficient R and Cy ≦ R, the current output value Cy does not exceed the span width, and therefore it is not considered that the output value does not change due to overflow. It is determined that the aggregate storage bin 4 is empty (S30).

When it is determined that the aggregate storage bin 4 is empty, the output value C is replaced with zero and the storage level display value Out is set to 0% in order to correct the electrical deviation of the output value C of the level sensor 10. Is displayed as (S31). Finally, it is determined whether or not the operation is completed (S32). If the operation is continued, the process returns to S24 to wait for the discharge gate to be opened, and if the operation is completed, the process proceeds to END to end the operation.

As described above, when the aggregate storage bin 4 is full or empty, it is possible to check whether the output value C of the level sensor 10 is electrically displaced, and thus the displacement is detected. When it occurs, you can correct the correction coefficient,
The output value is modified so that the output value C does not deviate from the storage level display value.

A torque motor type level meter or the like is provided at an appropriate height position of the aggregate storage bin 4 to check whether the storage level is accurately displayed or not, and the electrostatic capacity is measured at that height position. The storage level value detected by the formula level sensor 10 may be checked, and if an error occurs, the correction coefficient may be corrected to bring it closer to the accurate storage level display value.

[0037]

As described above, according to the present invention, the storage level display value is obtained by adding the correction coefficient R to the output value taken from the electrostatic capacity type level sensor 10 arranged in the aggregate storage bin 4. Although the correction coefficient is set in advance before the operation is started, the delivery of the aggregate from the aggregate storage bin 4 is stopped, and the aggregate is put into the aggregate storage bin 4. If there is a change in the output value before and after being taken in from the level sensor 10 during the time period during which is stopped, that is, during the operation interruption,
The correction coefficient R is corrected according to the change rate of these output values so as not to change the storage level display value, and then the correction coefficient Rx is changed to the previously set correction coefficient R to change the corrected correction coefficient Rx to the output value of the level sensor 10. Therefore, even if the atmosphere inside the aggregate storage bin 4 changes, the storage level can be displayed almost accurately and can be measured simply by a capacitance level meter as in the conventional case. It is possible to display a continuous level that is more accurate than that displayed by. Further, by this, the operator can grasp the change in the storage level almost accurately and can perform more efficient operation.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of an asphalt plant adopting the storage level measuring method of the present invention.

FIG. 2 is a flowchart showing a procedure of a storage level measuring method.

FIG. 3 is a flowchart showing a procedure of a storage level measuring method.

FIG. 4 is a flowchart showing a procedure of a storage level measuring method.

FIG. 5 is a flowchart showing a procedure of a storage level measuring method.

[Explanation of sign]

 DESCRIPTION OF SYMBOLS 1 ... Bucket elevator 2 ... Dryer 4 ... Aggregate storage bin 10 ... Level sensor 12 ... Level display device 13 ... Calculation part 14 ... I / O part 15 ... Input part 16 ... Display part 17 ... Storage part

Claims (1)

[Claims] 1. An electrostatic capacity type level sensor is provided in an aggregate storage bin of an asphalt plant that stores heated aggregates, and an output value from the level sensor is taken into a control unit every predetermined time for correction. The storage level display value is calculated in consideration of the coefficient, the storage level display value is output and displayed on the display unit, and the dispensing of the aggregate from the aggregate storage bin is stopped,
In addition, during the time when the loading of aggregate into the aggregate storage bin is stopped, the output values before and after the level sensor is compared are compared. Calculate the fluctuation rate, modify the value of the correction coefficient according to the fluctuation rate so that the storage level display value does not fluctuate, then change the correction coefficient to the previously set correction coefficient and output the corrected correction coefficient of the level sensor. A storage level display method for an aggregate storage bin of an asphalt plant, wherein the storage level display value is calculated in consideration of the value.