Mining open channel flow measuring device and measuring method

Abstract

The invention discloses a mining open channel flow measuring device which comprises a host, a flow velocity and water level sensor and a mud level sensor, the host is connected with the mud level sensor and the flow velocity and water level sensor through cables, and the flow velocity and water level sensor is arranged on a mounting support. The invention further discloses a mining open channel flow measurement method. The method specifically comprises the steps that the installation support, the sensor shell in the flow speed and water level sensor and the mud level sensor are installed on the open channel; measuring the vertical distance from the lower surface of the sensor shell to the bottom of the measured open channel, and measuring the upper channel width and the lower channel width of the open channel; measuring the flow velocity of the open channel by using a flow velocity water level sensor, and calculating the flow of the open channel; the height of sludge in the open channel is measured through the sludge level sensor, and then the open channel overflowing sectional area is calculated. According to the mining open channel flow measuring device, when the open channel flow is tested, a weir groove does not need to be built, the open channel structure is not changed, the operation difficulty is small, the cost is low, and the risk caused by building the weir groove is eliminated.

Description

Technical Field

[0001] This invention belongs to the technical field of flow testing equipment, specifically relating to a flow measurement device for open channels in mines, and also to a flow measurement method for open channels in mines. Background Technology

[0002] During mining operations, a large amount of mine water needs to be discharged through underground open channels. Timely monitoring of groundwater dynamics and early warning of water hazards are crucial for ensuring the safety of mine property and lives. Existing contactless open channel flow metering devices offer high measurement accuracy, good stability, and simple installation and maintenance, but they can only be used for online automatic flow monitoring of rivers and large open channels. Mine underground open channels are generally narrow and the environment is harsh, which limits the use of most equipment. At present, the main method used in mines is to use level gauges in conjunction with weirs to measure the flow of open channels. This method has very obvious defects: (1) Weirs need to be built and the structure of the open channel needs to be changed. However, not all mine open channels have the conditions to build weirs, and the construction of weirs is a large-scale project with high operational difficulty; (2) Weirs are prone to blockage due to structural problems, resulting in overflow; (3) The flow measurement by weir method is based on experience and is affected by many factors, resulting in a large error; (4) There will be silt in the mine open channel, which will further increase the measurement error of the open channel flow; (5) The water quality of the mine open channel is poor, there are many debris, the equipment is unstable, the maintenance workload is large, and the maintenance cost is high. Summary of the Invention

[0003] The purpose of this invention is to provide a flow measurement device for open channels in mines, which solves the problems of difficult layout and large measurement error of flow measurement equipment in the prior art.

[0004] Another objective of this invention is to provide a method for measuring the flow rate of open channels in mines.

[0005] The technical solution adopted in this invention is a mine open channel flow measurement device, including a main unit, a flow velocity and water level sensor and a mud level sensor. The main unit is connected to the mud level sensor and the flow velocity and water level sensor respectively through cables. The flow velocity and water level sensor is installed on a mounting bracket.

[0006] The invention is further characterized in that,

[0007] The mounting bracket includes a mounting base plate with an inverted L-shaped adjusting rod. The flow rate and water level sensor is fixed to the end of the inverted L-shaped adjusting rod by hex screws. The main unit includes a main unit housing with a main unit circuit board inside. The main unit circuit board also has an LCD screen and buttons. The buttons are soldered onto the main unit circuit board, and the main unit circuit board and the LCD screen are connected by pins.

[0008] The flow rate and water level sensor includes a sensor housing with a right-angled trapezoidal cross-section. The sensor housing is installed at the end of an inverted L-shaped adjusting rod. Inside the sensor housing are a speed sensor, a distance sensor, and a splitter terminal. The speed sensor and the distance sensor are both connected to one end of the splitter terminal, and the other end of the splitter terminal is connected to a cable. The cable is electrically connected to the main circuit board.

[0009] The speed sensor is located on the inclined surface of the sensor housing; the distance sensor is located at the bottom of the sensor housing.

[0010] The mud level sensor includes a housing, inside which a data acquisition module is installed. The data acquisition module is connected to the main circuit board via a cable. It also includes a light signal transmitting board and a light signal receiving board. The light signal transmitting board has several light-emitting diodes (LEDs) arranged at equal intervals, and the light signal receiving board has several photodiodes arranged at equal intervals. The LEDs and photodiodes have corresponding lamp heads. Both the LEDs and photodiodes are electrically connected to the data acquisition module.

[0011] Another technical solution adopted in this invention is a method for measuring the flow rate of open channels in mines, which is implemented according to the following steps:

[0012] Step 1: Install the mounting bracket, the sensor housing of the flow velocity and water level sensor, and the optical signal transmitting board and optical signal receiving board of the mud level sensor on the open channel;

[0013] Step 2: After the equipment is installed, measure the vertical distance L1 from the lower surface of the sensor housing to the bottom of the open channel being measured, and measure the upper channel width a and the lower channel width b of the open channel.

[0014] Step 3: Measure the flow velocity and water level in the open channel using a velocity-level sensor; measure the silt height in the open channel using a silt level sensor, then calculate the cross-sectional area of ​​the open channel, and finally calculate the flow rate of the open channel using the velocity-area method. Specifically:

[0015] When the velocity sensor and distance sensor in the flow velocity and water level sensor are activated, the velocity sensor emits electromagnetic waves in the direction of the water flow. When these electromagnetic waves encounter the moving water surface, part of the waves are reflected, producing a Doppler frequency shift effect. This reflection is received by the velocity sensor and fed back to the main circuit board. According to the Doppler frequency formula F = (V ± V) / (V0) t ) / (V±V s f, where f is the frequency of the electromagnetic wave emitted by the speed sensor, F is the frequency of the electromagnetic wave received by the speed sensor after reflection from the water surface, and V is the propagation speed of the electromagnetic wave. s If we set it to 0, we obtain the surface water velocity V of the measured open channel. t = (F / f-1)V, which is the flow velocity of the entire open channel;

[0016] The ranging sensor emits ultrasonic waves perpendicular to the water surface. Upon encountering the water, the waves are reflected, and a portion of the ultrasonic signal is received by the ranging sensor and fed back to the main circuit board. According to Y=VT, where V is the speed of sound in air and T is the distance from emission to the water surface...

[0017] The reflection is half the time it takes for the distance sensor to receive the data. Y is the distance from the distance sensor to the surface of the open channel. Combined with the installation height, the water level height of the open channel can be calculated as h = L1 - Y.

[0018] When the mud level sensor is working, the data acquisition module feeds back the collected data to the main circuit board. The distance h1 from the mud-water interface to the bottom of the mud level sensor is calculated as (n-1)*L. Therefore, the distance h1 from the mud-water interface to the bottom of the mud level sensor is the height of the silt in the open channel. Then, the cross-sectional area of ​​the open channel is calculated as S = ((ab)*(h+h1) / H+2b)*(h-h1) / 2. According to the velocity-area method: Q = V t S represents the flow rate of the open channel;

[0019] The beneficial effects of the present invention are: the mine open channel flow measurement device of the present invention does not require the construction of weirs or the alteration of the open channel structure when conducting open channel flow tests. It only requires fixing the sensor on the open channel as required, which is easy to operate, low in cost, and eliminates the risks caused by the construction of weirs. Attached Figure Description

[0020] Figure 1 This is a schematic diagram (I) of the structure of the mine open channel flow measurement device of the present invention;

[0021] Figure 2 This is a schematic diagram (II) of the structure of the mine open channel flow measurement device of the present invention;

[0022] Figure 3 This is a schematic diagram of the installation of the mine open channel flow measurement device of the present invention.

[0023] In the diagram: 1. Main unit; 2. Flow rate and water level sensor; 3. Mud level sensor; 4. Mounting bracket; 5. Cable; 6. Main unit circuit board; 7. Main unit housing; 8. LCD screen; 9. Button; 10. Sensor housing; 11. Speed ​​sensor; 12. Distance sensor; 13. Terminal block; 14. Hex screw; 15. Inverted L-shaped adjustment rod; 16. Mounting base plate; 17. Housing; 18. Optical signal transmitting board; 19. Optical signal receiving board; 20. Data acquisition module. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0025] Example 1

[0026] The present invention provides a mine open channel flow measurement device, such as... Figure 1 As shown, it includes a main unit 1, a flow rate and water level sensor 2 and a mud level sensor 3. The main unit 1 is connected to the mud level sensor 3 and the flow rate and water level sensor 2 respectively via a cable 5. The flow rate and water level sensor 2 is mounted on the mounting bracket 4.

[0027] like Figure 2 As shown, the mounting bracket 4 includes a mounting base plate 16, on which an inverted L-shaped adjusting rod 15 is provided. The flow velocity and water level sensor 2 is fixed to the end of the inverted L-shaped adjusting rod 15 by hexagonal screws 14. The inverted L-shaped adjusting rod 15 is used to adjust the installation height and horizontal length of the mounting bracket 4 to ensure that the flow velocity and water level sensor 2 can be positioned at the center line of the open channel. The mounting bracket 4 is finally fixed to the ground along the edge of the open channel with expansion bolts to complete the installation.

[0028] like Figure 2 As shown, the host 1 includes a host housing 7, a host circuit board 6 is disposed inside the host housing 7, an LCD screen 8 and a button 9 are also disposed on the host circuit board 6, the button 9 is soldered to the host circuit board 6, and the host circuit board 6 and the LCD screen 8 are connected by a pin.

[0029] The flow velocity and water level sensor 2 includes a sensor housing 10 with a right-angled trapezoidal cross-section. The sensor housing 10 is mounted on a mounting bracket 4. Inside the sensor housing 10 are a speed sensor 11, a distance sensor 12, and a wiring terminal 13. The speed sensor 11, distance sensor 12, and wiring terminal 13 are all fixed to the sensor housing 10 with screws. The speed sensor 11 and distance sensor 12 are both connected to one end of the wiring terminal 13. The other end of the wiring terminal 13 is connected to a cable 5, which is electrically connected to the main circuit board 6. The wiring at both ends of the wiring terminal 13 corresponds one-to-one. The speed sensor 11 is located on the inclined surface of the sensor housing 10. The distance sensor 12 is located at the bottom of the sensor housing 10.

[0030] The mud level sensor 3 includes a housing 17, inside which a data acquisition module 20 is installed. The data acquisition module 20 is connected to the main circuit board 6 via a cable 5. It also includes a light signal transmitting board 18 and a light signal receiving board 19. A number of light-emitting diodes (LEDs) are evenly spaced on the light signal transmitting board 18, and a number of photodiodes are evenly spaced on the light signal receiving board 19. The LEDs and photodiodes have corresponding lamp heads. Both LEDs and photodiodes are electrically connected to the data acquisition module 20. The light signal transmitting board 18 and the light signal receiving board 19 are installed in parallel at the lower part of the housing 17. The fixed distance between the LEDs and photodiodes is L. The LEDs and photodiodes are numbered from the bottom of the light signal transmitting board 18 and the light signal receiving board 19 upwards, with the bottom LED numbered 1 and the top LED numbered n. The maximum number of LEDs is 64.

[0031] The device of this invention is simple to install, requires little work and is easy to execute. It does not require changes to the open channel structure and can be applied to various complex installation environments underground.

[0032] Example 2

[0033] The present invention provides a method for measuring the flow rate of open channels in mines, which is implemented according to the following steps:

[0034] Step 1: Fix the mounting base plate 16 of the mounting bracket 4 to the edge of the open channel being measured using expansion bolts. Fix the optical signal transmitting board 18 and the optical signal receiving board 19 to the side wall of the open channel being measured using expansion bolts, ensuring that the bottom ends of the optical signal transmitting board 18 and the optical signal receiving board 19 coincide with the bottom of the open channel. Figure 3 As shown, the position of the flow velocity and water level sensor 2 is adjusted to the centerline of the open channel being measured by using the inverted L-shaped adjusting rod 15, so that the inclined surface of the sensor housing 10 in the flow velocity and water level sensor 2 faces the direction of the water flow in the open channel, and the lower surface of the sensor housing 10 is perpendicular to the bottom of the open channel.

[0035] Step 2: After the equipment is installed, measure the vertical distance L1 from the lower surface of the sensor housing 10 to the bottom of the open channel being measured, and measure the upper channel width a and the lower channel width b of the open channel.

[0036] Step 3: Speed ​​sensor 11 and distance sensor 12 are activated. Speed ​​sensor 11 emits electromagnetic waves towards the water flow. When the electromagnetic waves encounter the moving water surface, part of the electromagnetic waves are reflected, producing a Doppler frequency shift effect. This is received by speed sensor 11 and fed back to the main circuit board 6. According to the Doppler frequency formula, F = ((V ± V) t ) / (V±V s The electromagnetic wave frequency f emitted by speed sensor 11, after reflection from the water surface, is the frequency F of the electromagnetic wave received by speed sensor 11. The propagation speed of the electromagnetic wave is V. Since speed sensor 11 is stationary, its speed is V. s If we set it to 0, we obtain the surface water velocity V of the measured open channel. t = (F / f-1)V. Since the overall depth of the open channel is small, according to the distribution law of the average flow velocity of the open channel, within a certain range, the surface velocity of the open channel can represent the average value of the flow velocity of each layer of the open channel, which is the velocity of the entire open channel.

[0037] The ranging sensor 12 emits ultrasonic waves perpendicular to the water surface. After encountering the water surface, the waves are reflected. Part of the ultrasonic signal is received by the ranging sensor 12 and fed back to the main circuit board 6. According to Y=VT, where V is the speed of ultrasonic wave propagation in the air, T is half the time it takes for the ultrasonic wave to travel from emission to reflection by the water surface and be received by the ranging sensor, and Y is the distance from the ranging sensor 12 to the surface of the open channel, the water level height h=L1-Y of the open channel can be calculated by combining the installation height.

[0038] Temperature compensation circuits are designed in both the speed sensor 11 and the distance sensor 12 to compensate for the measurement errors of flow velocity and water level caused by temperature drift, so as to ensure the accuracy of flow velocity and water level measurement.

[0039] The mud level sensor 3 operates by determining the position of the mud-water interface based on the different intensity of the received light signal. The data acquisition module 20 feeds back the acquired data to the main circuit board 6. Based on the diode number n at the mud-water interface position and the fixed spacing L of the evenly distributed diodes, the distance h1 from the mud-water interface to the bottom of the mud level sensor 3 is calculated as h1 = (n-1)*L. When installing the mud level sensor, the bottom of the mud level sensor is close to the bottom of the open channel, and the distance between the diode and the bottom of the channel is almost negligible. Therefore, the distance h1 from the mud-water interface to the bottom of the mud level sensor is the height of the silt in the open channel.

[0040] The cross-sectional area of ​​the open channel is then calculated as S = ((ab)*(h+h1) / H+2b)*(h-h1) / 2, and according to the velocity-area method: Q = V t S represents the flow rate of the open channel;

[0041] The device of this invention uses a non-contact measurement method for flow velocity and water level. The equipment operates stably, has no requirements on water quality, and adds the measurement of silt height, which solves the problem of large flow error caused by silt and further improves the measurement accuracy.

[0042] The measurement method of this invention accurately measures all key parameters used in calculating open channel flow. Existing underground open channel measurement equipment uses liquid level measurement in conjunction with weirs and flumes, combined with empirical values, to obtain the flow rate of the open channel. According to the flow calculation formula Q=VS, the flow rate is calculated by accurately measuring the flow velocity V and the cross-sectional area S. In this measurement method, by measuring the flow velocity V of the underground open channel, combined with the measured water level h in the open channel, and the known upper channel width a and lower channel width b, the cross-sectional area S=((ab)h / H+2b)*h / 2 can be calculated. However, due to the harsh underground environment and poor water quality, there is a certain height of silt h1 in the open channel. By accurately measuring the height of the silt in the open channel, the error in the cross-sectional area calculation caused by the silt height is eliminated, S=((ab)*(h+h1) / H+2b)*(h-h1) / 2, thereby reducing the error in the open channel flow calculation. In existing methods, the flow rate of open channels is calculated based on the water level, without eliminating the error caused by the height of silt in the channel. This results in a relatively large error in the obtained flow rate. In addition, the weir method is based on empirical values ​​and has high requirements for environmental and operational conditions, which may not be met in actual use, or even impossible to construct weirs and flues, further increasing the error. Although the error in the cross-sectional area caused by the height of silt may be small, it is multiplied by 3600s*V when converted to flow rate, resulting in a large overall coefficient and thus a much larger error in the final flow rate.

[0043] Example 3

[0044] Using the mine open channel flow measurement device of this invention, flow measurement is performed on the pipeline. After parameter setting, the calculated flow cross-sectional area is consistent with the flow area of ​​the pipeline. A water pump circulates the water in the pipeline. A mass flow meter is connected to the pipeline as a standard meter. The sensor, utilizing its unique penetration characteristics, measures the flow rate in the PVC pipe of the pipeline. The operating frequency of the water pump is adjusted to change the flow rate in the pipeline. As can be seen from the test records in Table 1, at different frequencies, the error between the measurement data of the open channel sensor and the data of the mass flow meter is consistently maintained within 1m. 3 Within / h.

[0045] Table 1 Comparison of measurement data from open channel sensors and mass flow meters

[0046]

[0047]

Claims

1. A flow measurement device for open channels in mines, characterized in that, It includes a main unit (1), a flow rate and water level sensor (2) and a mud level sensor (3). The main unit (1) is connected to the mud level sensor (3) and the flow rate and water level sensor (2) respectively via cables (5). The flow rate and water level sensor (2) is mounted on a mounting bracket (4).

2. The mine open channel flow measurement device as described in claim 1, characterized in that, The mounting bracket (4) includes a mounting base plate (16), on which an inverted L-shaped adjusting rod (15) is provided. The flow rate and water level sensor (2) is fixed to the end of the inverted L-shaped adjusting rod (15) by an internal hex screw (14). The main unit (1) includes a main unit housing (7), in which a main unit circuit board (6) is provided. The main unit circuit board (6) is also provided with an LCD screen (8) and a button (9). The button (9) is soldered to the main unit circuit board (6). The main unit circuit board (6) and the LCD screen (8) are connected by a pin.

3. The mine open channel flow measurement device as described in claim 2, characterized in that, The flow rate and water level sensor (2) includes a sensor housing (10) with a right-angled trapezoidal cross-section. The sensor housing (10) is installed at the end of an inverted L-shaped adjusting rod (15). Inside the sensor housing (10) are a speed sensor (11), a distance sensor (12), and a splitter terminal (13). The speed sensor (11) and the distance sensor (12) are both connected to one end of the splitter terminal (13). The other end of the splitter terminal (13) is connected to a cable (5). The cable (5) is electrically connected to the main circuit board (6).

4. The mine open channel flow measurement device as described in claim 3, characterized in that, The speed sensor (11) is located on the inclined surface of the sensor housing (10); the distance sensor (12) is located at the bottom of the sensor housing (10).

5. The mine open channel flow measurement device as described in claim 3, characterized in that, The mud level sensor (3) includes a housing (17), inside which a data acquisition module (20) is installed. The data acquisition module (20) is connected to the main circuit board (6) via a cable (5). It also includes an optical signal transmitting board (18) and an optical signal receiving board (19). The optical signal transmitting board (18) is provided with a plurality of light-emitting diodes at equal intervals, and the optical signal receiving board (19) is provided with a plurality of photodiodes at equal intervals. The lamp heads of the light-emitting diodes and the photodiodes correspond one-to-one. Both the light-emitting diodes and the photodiodes are electrically connected to the data acquisition module (20).

6. A method for measuring the flow rate of open channels in mines, implemented using the flow rate measuring device for open channels in mines as described in claim 5, characterized in that, The specific steps are as follows: Step 1: Install the mounting bracket (4), the sensor housing (10) in the flow velocity and water level sensor (2), the optical signal transmitting board (18) and the optical signal receiving board (19) in the mud level sensor (3) on the open channel; Step 2: After the equipment is installed, measure the vertical distance L1 from the lower surface of the sensor housing (10) to the bottom of the open channel to be measured, and measure the upper channel width a and the lower channel width b of the open channel. Step 3: Use the flow velocity and water level sensor (2) to measure the flow velocity of the open channel; use the mud level sensor (3) to measure the height of the silt in the open channel, and then calculate the cross-sectional area of ​​the open channel and the flow rate of the open channel.

7. The method for measuring the flow rate of an open channel in a mine as described in claim 6, characterized in that, In step 1, specifically: The mounting base plate (16) in the mounting bracket (4) is fixed to the edge of the open channel to be measured by expansion bolts. The light signal transmitting board (18) and the light signal receiving board (19) are fixed to the side wall of the open channel to be measured by expansion bolts, so that the bottom of the light signal transmitting board (18) and the light signal receiving board (19) coincides with the bottom of the open channel. The fixed distance between the light-emitting diode and the photodiode is L. The light-emitting diode and the photodiode are numbered from the bottom of the light signal transmitting board (18) and the light signal receiving board (19) upwards, and the diode at the top is numbered N. The position of the flow velocity and water level sensor (2) is adjusted to the center line position of the open channel to be measured by the inverted L-shaped adjusting rod (15), so that the inclined surface of the sensor housing (10) in the flow velocity and water level sensor (2) faces the direction of the water flow in the open channel, and the lower surface of the sensor housing (10) is perpendicular to the bottom of the open channel.

8. The method for measuring the flow rate of an open channel in a mine as described in claim 7, characterized in that, Step 3 specifically involves: When the velocity sensor (11) and distance sensor (12) in the flow velocity and water level sensor (2) are activated, the velocity sensor (11) emits electromagnetic waves in the direction of the water flow. When the electromagnetic waves encounter the moving water surface, part of the electromagnetic waves are reflected, producing a Doppler frequency shift effect. This effect is received by the velocity sensor (11) and fed back to the main circuit board (6). According to the Doppler frequency formula F = ((V ± V) t ) / (V±V s The electromagnetic wave frequency f emitted by the speed sensor (11) is F after reflection from the water surface. The propagation speed of the electromagnetic wave is V. s If we set it to 0, we obtain the surface water velocity V of the measured open channel. t = (F / f-1)V, which is the flow velocity of the entire open channel; The distance sensor (12) emits ultrasonic waves vertically to the water surface. After encountering the water surface, the waves are reflected. Part of the ultrasonic signal is received by the distance sensor (12) and fed back to the main circuit board (6). According to Y=VT, where V is the speed of ultrasonic wave propagation in the air, T is half the time from the emission of the ultrasonic wave to its reflection by the water surface and its reception by the distance sensor, and Y is the distance from the distance sensor (12) to the surface of the open channel, the water level height h=L1-Y of the open channel can be calculated by combining the installation height. The mud level sensor (3) operates, and the data acquisition module (20) feeds back the acquired data to the main circuit board (6). The distance h1 from the mud-water interface to the bottom of the mud level sensor (3) is calculated as (n-1)*L. The distance h1 from the mud-water interface to the bottom of the mud level sensor is the height of the silt in the open channel. Then, the cross-sectional area of ​​the open channel is calculated as S = ((ab)*(h+h1)+2b)*(h-h1) / 2. According to the velocity-area method: Q = V t S represents the flow rate of the open channel.

Images