JP7209418B2 - POWDER FLOW MEASUREMENT DEVICE AND POWDER INTEGRATED FLOW MEASUREMENT METHOD - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder flow rate measuring device and a powder integrated flow rate measuring method using the powder flow rate measuring device.

Conventionally, in tunnel construction by the NATM construction method, construction is carried out by spraying shotcrete using a spraying device in order to prevent the occurrence of separation and collapse of bedrock and earth and sand in the excavated ground. In general, a quick-setting agent is often added to shotcrete in order to shorten the setting time and increase the strength at an early stage from several hours to a day.

The quick-setting agent is mixed with the sprayed concrete in front of the nozzle of the spraying device. , a configuration is disclosed in which an amount of quick-setting agent is added in accordance with the pumped amount of concrete while referring to the output value of the flow meter.

JP-A-1-285310

In the above-mentioned Patent Document 1, an electromagnetic flow meter, a positive displacement flow meter, etc. are adopted as a flow meter for detecting the flow rate of the quick setting agent, and it is assumed that the liquid quick setting agent is used for the shot concrete. However, in general, a powdery quick-setting agent is often used.

When using such a powdery quick-setting agent, it is difficult to measure the flow rate with an electromagnetic flowmeter or a positive displacement flowmeter. Microwave type powder flowmeters are widely used as flowmeters that can measure the flow rate of powder, but when attached to equipment for construction work such as spraying equipment, powder cannot be detected with high accuracy. However, it is known that the measurement accuracy is greatly degraded in the method, and there is a problem in practical use.

Therefore, when performing a spraying work with sprayed concrete to which powdery quick-setting agent is added, a spraying test is performed in advance to determine the amount of quick-setting agent to be added, and a quick-setting agent discharge device The relationship between the number of revolutions of the discharge electric motor and the discharge amount of the quick-setting agent is grasped. Then, the spraying operation is carried out with the addition amount of the quick-setting agent determined in advance, and the adjustment of the addition amount of the quick-setting agent during the operation is performed by controlling the rotation speed of the discharging electric motor.

However, since the rotation speed of the discharging electric motor is manually controlled by an operator, the amount of quick-setting agent to be added tends to vary. In addition, even if the rotation speed is controlled, it is likely that the discharge amount of the quick-setting agent corresponding to the rotation speed does not match the amount that was determined in advance and the actual amount. unable to comprehend. For this reason, during spraying work, workers must visually check how well the sprayed concrete has settled on the ground, etc., to determine whether it is excessive or insufficient, and also check the empty bags of quick-setting agent after the work is completed. We are trying to figure out the actual amount added.

The present invention has been made in view of such problems, and its main purpose is to provide a powder flow rate measuring device and a powder flow rate measuring device that can accurately grasp the integrated flow rate of powder with simple equipment. It is an object of the present invention to provide a method for measuring the integrated flow rate of a body.

In order to achieve such an object, the powder flow rate measuring device of the present invention comprises a powder flow tube made of a microwave permeable material and having a flow rate detection section in the middle thereof; A powder flow meter equipped with a microwave Doppler sensor installed on the outer peripheral surface side, and made of a microwave reflective material, the outer peripheral surface of the powder flow tube is positioned upstream and downstream with the flow rate detection unit interposed therebetween. and a microwave-absorbing material, and the boundaries between the upstream end and the downstream end of the general covering material and the outer peripheral surface of the powder flow tube. and an end covering material for covering the.

According to the powder flow rate measuring device of the present invention described above, since the powder flow tube is made of a microwave-transmissive material and the powder flow meter is arranged on the outer peripheral surface of the powder flow tube, the microwave Doppler sensor is The powder to be measured can smoothly flow down the inside of the powder flow pipe without protruding inward of the powder flow pipe.

Further, the outer peripheral surface of the powder flow tube is covered with a general covering material made of a microwave absorbing material or a general covering material made of a microwave reflecting material and an end covering material made of a microwave absorbing material. Since the powder flow tube is covered with the powder flow tube, it is possible to eliminate the disturbance environment where the microwaves positioned outside the powder flow tube are reflected. Therefore, it is possible to accurately measure the integrated flow rate of the powder to be measured by the powder flow rate measuring device in any environment.

Furthermore, by providing a vibration isolator that suppresses the transmission of vibration to the powder flow pipe, powder flow rate measurement can be performed on a device that generates vibration, such as a spraying device used when spraying concrete on the ground. Even if the device is installed, it is possible to minimize the influence of vibration and measure the integrated flow rate of powder with higher accuracy.

A method for measuring an integrated flow rate of powder according to the present invention is a method for measuring an integrated flow rate of powder using the apparatus for measuring an integrated flow rate of powder according to the present invention. While measuring the sensor output value related to the integrated flow rate with the powder flow meter at regular time intervals, the integrated value of the mass of the sample that has flowed down is measured, and the integrated value of the mass and the sensor related to the integrated flow rate are measured. Regression analysis using the output value is performed, the sensor output value obtained from the powder flow meter when the powder to be measured flows down the powder flow tube is used as an explanatory variable, and the integrated flow rate of the powder to be measured is A prediction formula calculation step of calculating a prediction formula used as an objective variable, a device installation step of installing the powder flow rate measuring device in the transportation pipe of the powder to be measured, and the integrated flow rate of the powder to be measured It is characterized by comprising an integrated flow rate calculation step of calculating based on the sensor output value obtained from the powder flow rate measuring device and the prediction formula.

According to the method for measuring the integrated flow rate of powder of the present invention described above, the sensor output value of the powder flow meter when the powder to be measured flows down the powder flow tube is used as an explanatory variable, and the powder to be measured is integrated. After calculating in advance a prediction formula with the flow rate as the objective variable, the integrated flow rate of the powder to be measured (flowing down It is possible to grasp the total mass of powder).

In the method for measuring the cumulative flow rate of powder of the present invention, in the device installation step, the powder flow rate measuring device is installed in a quick setting agent transportation pipe provided in a spraying device used when spraying concrete. Characterized by

According to the method of measuring the integrated flow rate of powder of the present invention described above, by outputting the sensor output value of the powder flow meter at regular intervals, the total mass of the quick-setting agent flowing down at that time, that is, the amount added, can be calculated. Since it can be grasped in real time, it becomes possible to quantitatively adjust the addition amount of the quick-setting agent even during the spraying operation.

As a result, even if the pumping amount of the sprayed concrete changes during the spraying operation, it is possible to add an appropriate amount of quick-setting agent corresponding to this change. In addition, it is possible to easily adjust the amount of quick setting agent to be added according to the ground conditions, etc. It is possible to finish.

According to the present invention, the outer peripheral surface of the powder flow tube made of a microwave-transmitting material is covered with a general-part coating made of a microwave-reflecting material and an end-covering made of a microwave-absorbing material. With a simple covering structure, it is possible to eliminate the disturbance environment that affects the microwave Doppler sensor provided in the powder flow meter, and to accurately grasp the integrated flow rate of the powder to be measured flowing through the powder flow tube. Become.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the outline of the powder flow-measuring apparatus in embodiment of this invention. It is a figure which shows the cross section of the powder flow-measuring apparatus in embodiment of this invention. It is a figure which shows a motion of the microwave in the powder flow pipe|tube in embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the whole spraying apparatus provided with the powder flow device in embodiment of this invention. It is a figure which shows the anti-vibration equipment of the powder flow rate measuring apparatus in embodiment of this invention. It is a figure which shows the state which equipped the powder flow rate measuring device in embodiment of this invention with the anti-vibration equipment and the protective box. FIG. 4 is a diagram showing the relationship between the integrated value of the mass of a sample flowing down the powder flow tube and the sensor output value related to the integrated flow rate obtained by the powder flow meter in the embodiment of the present invention.

The powder flow rate measuring device of the present invention is installed in a transportation pipe through which the powder to be measured flows down, so that the integrated flow rate (total mass of the powder to be measured) flowing down can be grasped. In the present embodiment, a case where the powder flow rate measuring device is installed in a quick-setting agent pressure-feeding hose provided in a sprayed concrete spraying device will be described in detail below with reference to FIGS. 1 to 7. explain.

<Powder flow rate measuring device>
As shown in FIGS. 1 and 2, the powder flow rate measuring device 1 includes a powder flow meter 2, a powder flow tube 3, a general part covering member 4, and an end covering member 5. The flow meter 2 is generally known as a microwave type powder flow meter, and can detect the powder to be measured flowing down the pipe with a microwave Doppler sensor 21 and output the integrated flow rate as a sensor output value. A flow meter is used.

The powder flow tube 3, as shown in FIG. 1, is a straight tube for flowing down the powder to be measured by the powder flow meter 2, and has a powder inlet 31 at one end and the other. A powder outlet 32 is provided at the end. Any material may be used as long as it is a microwave-permeable material, and a vinyl chloride pipe is used in this embodiment. The powder inflow part 31 and the powder outflow part 32 are each provided with a joint member 6, and are configured to be connectable to a transport pipe through which the powder to be measured flows.

A flow rate detection unit 33 is set in an intermediate portion of the powder flow pipe 3, and the powder flow meter 2 is installed in the flow rate detection unit 33. As shown in FIG. As shown in FIG. 2, the powder flowmeter 2 is installed via a flowmeter installation jig 7. The flowmeter installation jig 7 has a U-shaped portion 71 that holds the powder flow tube 3 at the bottom. , and a cylindrical portion 72 which is installed in the open portion of the U-shaped portion 71 and holds the powder flow meter 2 .

The powder flowmeter 2 is held by the flowmeter installation jig 7 in a state where the microwave Doppler sensor 21 is inserted into the cylindrical portion 72 , so that the microwave Doppler sensor 21 is positioned in the powder flow tube in the flow rate detection portion 33 . 3 facing the outer peripheral surface. Note that the microwave Doppler sensor 21 may be in contact with the powder flow tube 3 or may be arranged with an interval therebetween. Moreover, the powder flow meter 2 may be held by any means with respect to the cylindrical portion 72 of the flow meter installation jig 7 .

Furthermore, the outer peripheral surface of the powder flow tube 3 is covered with a general part covering material 4 in a predetermined range on the upstream side and the downstream side with respect to the flow rate detection section 33 . The general part covering material 4 is made of a microwave reflective material. It is used so that the reflected wave is not received by the microwave Doppler sensor 21 because it is reflected by an object.

In the present embodiment, a steel tape is used as the covering material 4 for the general part, the flowmeter installation jig 7 is included, and the portion facing the microwave Doppler sensor 21 of the powder flowmeter 2 in the powder flow tube 3 The above predetermined range is covered except for . If the flow meter installation jig 7 is made of a microwave reflective material, it is not necessarily covered with the general member covering material 4 .

With such a configuration, when the powder to be measured is caused to flow down inside the powder flow tube 3 while the microwave Doppler sensor 21 of the powder flow meter 2 is transmitting microwaves, the powder to be measured is reflected by the powder to be measured. The generated microwave is received by the microwave Doppler sensor 21 . Since the frequency of the received signal changes due to the Doppler effect, the powder flow meter 2 calculates the flow rate based on the change in the transmitted wave and the received wave, and then outputs the sensor output value related to the integrated flow rate. do.

On the other hand, as shown in FIG. 3( a ), microwaves that are not reflected by the powder to be measured but are repeatedly reflected by the general covering material 4 inside the powder flow tube 3 are is emitted to the outside of the powder flow tube 3 in the vicinity of the end thereof, and is reflected by any object positioned outside this. When this reflected wave returns to the inside of the powder flow tube 3 and is received by the microwave Doppler sensor 21, the measurement accuracy is greatly reduced. For this reason, in order to eliminate the disturbance environment which is located outside the powder flow tube 3 and reflects microwaves, an end covering member 5 is installed at the end of the general member covering member 4 .

As shown in FIGS. 1 and 3(b), the end covering material 5 is made of a material that has microwave absorbency and can cover the powder flow tube 3. As shown in FIG. In this embodiment, conductive silicone rubber is used, and the vicinity of the boundary between the upstream end and the outer peripheral surface of the powder flow tube 3 and the downstream end of the general part covering material 4 and the powder flow tube The vicinity of the boundary with the outer peripheral surface of 3 is covered. As a result, the microwaves reflected by the covering material 4 inside the powder flow tube 3 are absorbed by the end covering material 5 and are not emitted from the powder flow tube 3 to the outside.

The powder flow rate measuring device 1 having the configuration described above can be used, for example, when spraying shotcrete onto an excavated natural ground in tunnel construction by the NATM construction method as shown in FIG. It can be installed in a spraying device 10 used for application or the like.

The spraying apparatus 10 includes a material hose 13 through which shotcrete discharged from a concrete pump 11 and pressure-fed by compressed air supplied from a compressor 16 flows down, and a quick-setting agent adding device with compressed air also supplied from the compressor 16. A quick-setting agent pressure-feeding hose 14 for flowing down the powder-like quick-setting agent pressure-fed from the quick-setting agent pressure-feeding hose 14 is provided, and the powdery quick-setting agent flowing down the quick-setting agent pressure-feeding hose 14 is sent to the material hose in front of the spray nozzle 15. In 13 it joins and mixes with the shotcrete. The shotcrete mixed with the quick-setting agent is sprayed through the spray nozzle 15 .

In contrast to the spraying apparatus 10 having such a configuration, when the powder flow rate measuring device 1 is installed in the quick setting agent pressure feeding hose 14 through which the powdery quick setting agent flows down, the amount of the quick setting agent added to the sprayed concrete can be measured. can be measured. As for the installation position of the powder flow rate measuring device 1, the powder flow pipe 3 may be positioned in the middle of the quick-setting agent pressure-feeding hose 14, or the discharge port of the quick-setting agent adding device 12 and the quick setting agent addition device 12 may be installed. It may be provided so as to be positioned between the inflow port of the binder pressure-feeding hose 14 .

By the way, the quick-setting agent pumping hose 14 is likely to vibrate when the quick-setting agent is pumped by compressed air. When the powder flow rate measuring device 1 is installed in such an environment, the vibration is transmitted to the powder flow rate measuring device 1 as well. Waves cannot be accurately reflected, and measurement errors tend to occur in the output values of the powder flow meter 2 . Therefore, the powder flow rate measuring apparatus 1 should preferably be configured such that at least the powder flow tube 3 is provided with a vibration isolator 8 for suppressing the input of vibration.

As shown in FIG. 5, the vibration isolator 8 includes a base 81 that supports the lying powder flow tube 3 from below, and a U-shaped fixing member 82 that fixes the powder flow tube 3 to the base 81. , anchor bolts 83 for installing and fixing the pedestal 81 to an immovable part such as the ground or a concrete foundation.

Note that the vibration isolator 8 is not necessarily limited to the structure described above, and any structure that can suppress the vibration input to the powder flow rate measuring device 1 via the powder flow tube 3 can be adopted. may In addition, if vibration is transmitted to the powder flowmeter 2 due to an unforeseen event even if the vibration isolation equipment 8 is employed, a vibration isolation equipment for suppressing the transmission of vibration to the powder flowmeter 2 is further provided.

As shown in FIG. 6, the powder flow rate measuring device 1 having the above configuration is manufactured in advance in a factory or the like in a state in which at least a protection box 9 for protecting the powder flow rate meter 2 and a vibration isolator 8 are provided. Good. By doing so, the powder flow rate measuring device 1 can be safely transported to a construction site or the like, and the installation work to the spraying device 10 can be easily performed.

As described above, the powder flow rate measuring device 1 employs a microwave-transmissive material for the powder flow tube 3, and the powder flow meter 2 is arranged on the outer peripheral surface of the powder flow tube 3. Therefore, the microwave Doppler sensor 21 does not protrude inside the powder flow pipe 3, and the powder to be measured can smoothly flow down the inside of the powder flow pipe 3.

Further, since the outer peripheral surface of the powder flow tube 3 is covered with the general portion coating material 4 made of a microwave reflective material and the end portion coating material 5 made of a microwave absorptive material, the powder flow tube 3 is It is possible to eliminate a disturbance environment in which microwaves located in the direction are reflected. Therefore, the powder flow rate measuring device 1 can accurately measure the integrated flow rate of the powder to be measured in any environment.

In addition, if the configuration is provided with vibration isolation equipment 8, even if the powder flow rate measuring device 1 is installed in a device that generates vibration, the influence of vibration can be minimized, and the powder to be measured can be integrated with higher accuracy. It becomes possible to measure the flow rate.

<Method for measuring integrated flow rate of powder using powder flow rate measuring device 1>
Next, the method for measuring the integrated flow rate of powder using the powder flow rate measuring device 1 will be described by taking the case of measuring the integrated flow rate of the quick-setting agent flowing down the quick-setting agent pressure-feeding hose 14 provided in the spraying device 10 as an example. , are described below.

<Prediction formula calculation process>
First, a sample of quick-setting agent, which is powder to be measured, is prepared and stored in a storage tank equipped with a mass measuring unit such as a load cell. Next, the stored sample is made to flow down from the storage tank to the powder flow tube 3, and the sensor output value related to the integrated flow rate is measured by the powder flow meter 2 at regular intervals. On the other hand, at the same time interval as the measurement of the sensor output value, the integrated value of the mass of the sample flowing down from the storage tank is measured by the mass measurement unit provided in the storage tank.

After a predetermined time has passed, the correlation between the sensor output value related to the integrated flow rate measured by the powder flow meter 2 of the sample flowing down the powder flow tube 3 and the integrated value of the mass measured by the mass measuring unit is calculated. confirm. The scatter diagram of the measurement results shown in ^FIG . 7 is plotted with the integrated mass value on the horizontal axis and the sensor output value on the vertical axis. = 0.98). Regression analysis is performed after confirming the correlation, and the powder flow rate when the quick setting agent, which is the powder to be measured discharged from the quick setting agent pressure feeding hose 14 of the spraying device 10, flows down the powder flow pipe 3 A prediction formula is calculated using the sensor output value of total 2 as an explanatory variable and the integrated flow rate of quick-setting agent as an objective variable.

<Device installation process>
Next, the powder flow pipe 3 is connected to the quick-setting agent pressure-feeding hose 14 in the spraying device 10 or between the discharge port of the quick-setting agent adding device 12 and the inlet of the quick-setting agent pressure-feeding hose 14. are positioned between and connected via a joint member 6 . At the same time, the powder flow rate measuring device 1 is installed and fixed to an immovable portion such as the ground or concrete foundation by the vibration isolator 8, and measures are taken to prevent transmission of vibration to the powder flow pipe 3.

<Integrated flow rate calculation process>
After such advance preparations are completed, the spraying device 10 is operated in a state in which microwaves are emitted from the microwave Doppler sensor 21 of the powder flow meter 2 to start pumping the quick-setting agent. is made to flow down to the material hose 13 via the quick-setting agent pumping hose 14 and the powder flow pipe 3 . Then, the microwaves emitted from the microwave Doppler sensor 21 into the powder flow tube 3 are reflected by the quick-setting agent flowing down the powder flow tube 3 and received by the microwave Doppler sensor 21 .

The powder flowmeter 2 outputs a sensor output value related to the integrated flow rate based on changes in the microwave transmission wave and reception wave. By inputting the sensor output value output in this way into the prediction formula calculated in the prediction formula calculation step, the integrated flow rate of the quick-setting agent flowing down to the material hose 13, that is, the powder at the time of measuring the sensor output value It is possible to grasp the total mass of the quick-setting agent that has flowed down the flow rate detection portion 33 of the flow tube 3 (addition amount of the quick-setting agent).

Therefore, by outputting the sensor output value of the powder flow meter 2 at regular intervals, the amount of quick-setting agent added can be grasped in real time, so the amount of quick-setting agent added can be determined even during the spraying operation. Adjustment can be made quantitatively.

As a result, even if the pumping amount of the sprayed concrete changes during the spraying operation, it is possible to add an appropriate amount of quick-setting agent corresponding to this change. In addition, it is possible to easily adjust the amount of quick setting agent to be added according to the ground conditions, etc. It is possible to finish.

The powder flow rate measuring device 1 and the powder integrated flow rate measuring method of the present invention are not limited to the above-described embodiments, and various modifications are possible without departing from the scope of the present invention.

For example, in the present embodiment, as shown in FIG. 1, a microwave reflective material is used as the general part coating material 4 that coats the outer peripheral surface of the powder flow tube 3 . However, it is not necessarily limited to this, and a microwave absorbing material may be employed. In this case, the end covering material 5 can be omitted.

1 Powder flow rate measuring device 2 Powder flow meter 21 Microwave Doppler sensor 3 Powder flow tube 31 Powder inflow part 32 Powder outflow part 33 Flow rate detection part 4 General part covering material 5 End part covering material 6 Joint member 7 Flow rate Meter installation jig 71 U-shaped portion 72 Cylindrical portion 8 Anti-vibration equipment

10 Spraying device 11 Concrete pump 12 Quick-setting agent addition device 13 Material hose 14 Quick-setting agent pressure-feeding hose (rapid-setting agent transportation pipe)
15 spray nozzle 16 compressor

Claims (4)

a powder flow tube made of a microwave permeable material and having a flow rate detection part in the middle;
a powder flow meter installed on the outer peripheral surface side of the flow rate detection unit of the powder flow tube and equipped with a microwave Doppler sensor;
a general part coating material made of a microwave reflective material and covering the outer peripheral surface of the powder flow tube over a predetermined range on the upstream side and the downstream side with the flow rate detection part interposed therebetween;
an end covering material made of a microwave-absorbing material and covering the boundaries between the upstream end and the downstream end of the general covering material and the outer peripheral surface of the powder flow tube;
A powder flow rate measuring device comprising: In the powder flow rate measuring device according to claim 1,
A powder flow rate measuring device comprising a vibration isolator for suppressing transmission of vibration to the powder flow tube. A powder integrated flow rate measuring method using the powder flow rate measuring device according to claim 1 or 2 ,
A sample of the powder to be measured is flowed down the powder flow tube, and the sensor output value related to the integrated flow rate is measured by the powder flow meter at regular intervals, while the mass of the sample that has flowed down is integrated. is measured, regression analysis is performed using the integrated value of the mass and the sensor output value related to the integrated flow rate, and the sensor obtained from the powder flow meter when the powder to be measured flows down the powder flow tube a prediction formula calculation step of calculating a prediction formula using an output value as an explanatory variable and an integrated flow rate of the powder to be measured as an objective variable;
A device installation step of installing the powder flow rate measuring device in a transportation pipe for the powder to be measured;
an integrated flow rate calculation step of calculating the integrated flow rate of the powder to be measured based on the sensor output value obtained from the powder flow rate measuring device and the prediction formula;
A method for measuring an integrated flow rate of powder, comprising: In the method for measuring the integrated flow rate of powder according to claim 3 ,
In the device installation step, the powder flow rate measuring device is installed in a quick-setting agent transportation pipe provided in a spraying device used for spraying the sprayed concrete.

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