A device and method for on-line detection of concrete density in a transport pipeline

Abstract

An online detection device and method for concrete density in a transportation pipeline belongs to the field of construction engineering. The invention includes a mixer electrically connected to a controller, a concrete delivery pump, a three-way valve, a first ultrasonic probe, a second ultrasonic probe, a third ultrasonic probe, a controller, and a storage tank. The mixer is connected to the concrete delivery pump, the discharge pipe is connected to the concrete delivery pump, the return pipe is connected to the mixer, and the storage delivery pipe is connected to the storage tank. The discharge pipe, return pipe, and storage delivery pipe are respectively connected to the three ports of the three-way valve. The mixer is equipped with a third ultrasonic probe. The first and second ultrasonic probes are symmetrically mounted horizontally on the side walls of the two ends of the horizontal straight section of the discharge pipe. The discharge pipe is equipped with a pressure transmitter, a temperature transmitter, and a flow transmitter. This invention addresses the problem of the inability to detect the density of concrete in a transportation pipeline in real time by using a non-contact measurement device with ultrasonic probes to monitor the density of concrete in the pipeline.

Description

Technical Field

[0001] This invention relates to an online detection device for concrete density in transportation pipelines, belonging to the field of construction engineering. Background Technology

[0002] In construction projects, a large amount of concrete is required, and concrete plays a crucial role in the quality of the project. During actual construction, the concrete material is susceptible to influences from natural conditions, technical factors, and human factors, which can easily lead to quality problems in the concrete structure and even jeopardize the safety of the building when it is put into use. The quality of concrete is usually reflected in the production process of sand and gravel aggregates, differences in raw material weighing, and differences in mixing uniformity. Therefore, density testing of cement concrete is extremely necessary in the construction field, as it directly affects the workability, mechanical properties, and service life of cement concrete.

[0003] Mixing is the process of homogenizing the mixture and is a crucial step in concrete production. Currently, there are no online density testing devices for pipeline transportation in industrial settings; workers mainly rely on their experience to judge whether the quality of freshly mixed concrete meets requirements. Furthermore, there are instances where the concrete undergoes a phase change during transportation after being properly mixed at the batching plant, and the density value of concrete is affected by factors such as weather, temperature, pressure, and flow rate. Therefore, there is an urgent need to develop an efficient, real-time, and accurate device and method for detecting the density of freshly mixed concrete in transportation pipelines, thereby scientifically judging the quality of the mixed concrete within the pipeline and solving the aforementioned technical problems. Summary of the Invention

[0004] The purpose of this invention is to solve the problem of the inability to detect the density of concrete in transport pipelines in real time. A brief overview of the invention is provided below to offer a basic understanding of certain aspects of it. It should be understood that this overview is not an exhaustive summary of the invention. It is not intended to identify key or essential parts of the invention, nor is it intended to limit the scope of the invention.

[0005] The technical solution of the present invention:

[0006] Option 1: An online concrete density detection device for a transport pipeline, comprising a mixer, a concrete delivery pump, a discharge pipe, a return pipe, a storage and conveying pipe, a three-way valve, a first ultrasonic probe, a second ultrasonic probe, a third ultrasonic probe, a pressure transmitter, a temperature transmitter, a flow transmitter, a controller, and a storage tank. The discharge port of the mixer is connected to the inlet of the concrete delivery pump, one end of the discharge pipe is connected to the discharge port of the concrete delivery pump, one end of the return pipe is connected to the inlet of the mixer, and one end of the storage and conveying pipe is connected to the storage tank. The other ends of the material pipe and the storage and conveying pipe are respectively connected to the three ports of the three-way valve. A third ultrasonic probe is installed on the agitator. The discharge pipe has a horizontal straight pipe section. A first ultrasonic probe and a second ultrasonic probe are respectively installed horizontally and symmetrically on the side walls at both ends of the horizontal straight pipe section. A pressure transmitter, a temperature transmitter and a flow transmitter are installed sequentially on the discharge pipe. The agitator, the concrete conveying pump, the three-way valve, the first ultrasonic probe, the second ultrasonic probe, the third ultrasonic probe, the pressure transmitter, the temperature transmitter and the flow transmitter are respectively electrically connected to the controller.

[0007] Preferably, it also includes a local display, a first wireless communication module, and a second wireless communication module. The local display and the first wireless communication module are electrically connected to the controller, and the second wireless communication module receives the wireless signals transmitted by the first wireless communication module.

[0008] Preferably, the third ultrasonic probe is an integrated ultrasonic transceiver probe.

[0009] Preferably, the controller is a controller.

[0010] Option 2, an online method for detecting the density of concrete in a transportation pipeline, is based on the online concrete density detection device for transportation pipelines described in Option 1, and includes:

[0011] S1. After the mixer is fed, the concrete is initially mixed. The static concrete density value ρ1 in the mixer is measured by the transmission time of the third ultrasonic probe in the mixer. After the static concrete density value ρ1 in the mixer reaches the density requirement, it is transported to the concrete delivery pump through the discharge port of the mixer and then enters the discharge pipe.

[0012] S2. During the process of concrete being transported through the discharge pipe, the first ultrasonic probe and the second ultrasonic probe are used to measure the dynamic concrete density value ρ2 in the transport pipe based on the forward transmission time t1 and the reverse transmission time t2 of the ultrasonic waves in the discharge pipe containing concrete. The dynamic concrete density value ρ2 in the transport pipe is then transmitted to the local display through the controller for local display.

[0013] S3. During the conveying process of concrete in the discharge pipe, the pressure transmitter, temperature transmitter and flow transmitter measure the pressure, temperature and flow values ​​of the concrete in the pipe and transmit them to the local display through the controller for local display.

[0014] S4. The controller processes the received data values, which include the static concrete density value ρ1 in the mixer, the dynamic concrete density value ρ2 in the transport pipeline, the pressure value, the temperature value, and the flow rate value. The controller then transmits the received data values ​​to the PC terminal through the first wireless communication module and the second wireless communication module.

[0015] S5. The received data values ​​are displayed and change curves are plotted on the LabVIEW interface of the PC terminal. The measurement data is stored and the pressure value, temperature value and flow rate value are used as auxiliary references to determine whether the density of the discharge pipe is appropriate.

[0016] S6. Compare the dynamic concrete density value ρ2 in the transport pipeline with the set standard concrete density value. If they match, the concrete is transported to the storage tank or poured directly. If they do not match, proceed to step S7.

[0017] S7. Using a PC terminal, signals are transmitted to the controller via the first and second wireless communication modules. The controller controls the three-way valve to switch the concrete flow direction, so that the concrete flows back to the mixer through the return pipe to remix the concrete. Repeat steps S1-S6 until the dynamic concrete density value ρ2 in the transport pipeline is consistent with the set standard concrete density value.

[0018] Preferably, the concrete pump is connected to a frequency converter, which changes the pumping frequency of the concrete pump, thereby changing the pressure and flow rate of the concrete in the discharge pipe.

[0019] Preferably, the calculation process for the static concrete density value ρ1 in the mixer in step S1 is as follows:

[0020] The relationship between the propagation speed of the ultrasonic waves emitted by the third ultrasonic probe and the density and elastic modulus of the medium is as follows:

[0021]

[0022] In equation (1), c is the propagation speed of the ultrasonic wave emitted by the third ultrasonic probe in the mixer, and k is the volume compressibility coefficient of the fresh concrete.

[0023] During concrete mixing, the mixer rotates axially while the concrete remains relatively stationary radially. In this case, the relationship between the propagation speed and propagation time of the ultrasonic waves emitted by the third ultrasonic probe, using the ultrasonic propagation equation for stationary fluids, is as follows:

[0024]

[0025] In equation (2), d is the propagation distance of the ultrasonic wave emitted by the third ultrasonic probe in the radial propagation section of the stirrer, and t3 is the propagation time of the ultrasonic wave emitted by the third ultrasonic probe in the stirrer.

[0026] From equations (1) and (2), the static concrete density value ρ1 inside the mixer measured by the third ultrasonic probe is:

[0027]

[0028] Preferably, the calculation process for the dynamic concrete density value ρ2 in the transport pipeline in step S2 is as follows:

[0029] The relationship between the propagation speed of the ultrasonic wave emitted by the first ultrasonic probe and the density and elastic modulus of the medium is as follows:

[0030]

[0031] In equation (4), c0 is the propagation speed of the ultrasonic wave emitted by the first ultrasonic probe in the concrete mixture;

[0032] In the downstream flow, the concrete in the discharge pipe flows from the first ultrasonic probe to the second ultrasonic probe. The controller excites the first ultrasonic probe to emit ultrasonic signals. The first ultrasonic probe acts as an ultrasonic transmitting probe, and the second ultrasonic probe acts as an ultrasonic receiving probe. The received ultrasonic echo signals are processed by the controller. The relationship between the propagation speed and propagation time of the downstream ultrasonic waves is applicable to the ultrasonic propagation relationship of fluid flowing in the same direction, as shown by the following formula:

[0033]

[0034] In equation (5), d0 is the length of the horizontal straight pipe section between the first ultrasonic probe and the second ultrasonic probe, which is the propagation distance of the ultrasonic wave in the horizontal straight pipe section, t1 is the propagation time of the ultrasonic wave emitted by the first ultrasonic probe in the pipe along the direction of the concrete flow, and v is the flow velocity of the freshly mixed concrete in the discharge pipe.

[0035] In counter-current flow, the concrete in the discharge pipe flows from the second ultrasonic probe to the first ultrasonic probe. The controller excites the second ultrasonic probe to emit ultrasonic signals. The second ultrasonic probe acts as the ultrasonic transmitting probe, and the first ultrasonic probe acts as the ultrasonic receiving probe. The received ultrasonic echo signals are processed by the controller. The relationship between the propagation speed and propagation time of counter-current ultrasonic waves is applicable to the ultrasonic propagation relationship of fluids flowing in reverse:

[0036]

[0037] In equation (6), t2 is the propagation time of the ultrasonic wave emitted by the second ultrasonic probe in the reverse concrete flow within the pipe; from equations (5) and (6), the sum of the propagation times of the ultrasonic wave in the forward and reverse directions within the dynamic concrete pipe is:

[0038]

[0039] Since the propagation speed of ultrasound in concrete is much greater than the flow velocity of concrete in a pipe, equation (7) can be simplified to:

[0040]

[0041] From equations (4) and (8), the dynamic concrete density value ρ2 inside the transport pipeline can be obtained as:

[0042]

[0043] The present invention has the following beneficial effects:

[0044] 1. This invention addresses the problem of the inability to detect the density of concrete in transport pipelines in real time online. It designs an online detection device and method for concrete density in transport pipelines based on an ultrasonic probe. The device can monitor the density of concrete in the pipeline through a non-contact measurement device with an ultrasonic probe, adjust the flow direction and mixing time of the concrete in real time through a three-way valve, and upload the detection information to a PC through a wireless communication module for more accurate concrete density prediction. The wireless communication module also enables remote control of the concrete flow direction in the pipeline.

[0045] 2. This invention is applicable to the monitoring of the density of concrete mixtures in various conveying pipelines after the concrete has been mixed to the required standard by a mixer, when the mixing state of the concrete changes due to weather and transportation conditions, resulting in changes in the mixing quality. This allows for better assurance of the quality of the mixed concrete and is of great significance for improving the overall construction quality of buildings. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the installation of an online concrete density detection device for transportation pipelines.

[0047] Figure 2 This is a structural schematic diagram of an online concrete density detection device for transportation pipelines.

[0048] Figure 3 This is a flowchart of an online concrete density detection device for transportation pipelines;

[0049] Figure 4 This is a diagram of the online concrete density monitoring interface in specific embodiment two of the present invention;

[0050] In the diagram, 1-Agitator, 2-Concrete pump, 3-Discharge pipe, 4-Return pipe, 5-Storage and conveying pipe, 6-Three-way valve, 7-First ultrasonic probe, 8-Second ultrasonic probe, 9-Third ultrasonic probe, 10-Pressure transmitter, 11-Temperature transmitter, 12-Flow transmitter, 13-Controller, 14-Storage tank, 15-Local display, 16-First wireless communication module, 17-Second wireless communication module, 18-PC terminal, 19-Frequency converter, 31-Horizontal straight pipe section. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0052] The connections mentioned in this invention are divided into fixed connections and detachable connections. Fixed connections, also known as non-detachable connections, include but are not limited to conventional fixed connection methods such as folded connections, riveted connections, adhesive connections, and welded connections. Detachable connections include but are not limited to conventional disassembly methods such as threaded connections, snap-fit ​​connections, pin connections, and hinged connections. When a specific connection method is not explicitly defined, it is assumed that at least one existing connection method can always be found to achieve the function, and those skilled in the art can choose according to their needs. For example, a welded connection can be chosen for fixed connections, and a hinged connection can be chosen for detachable connections.

[0053] Specific implementation method one: Combining Figures 1-4 This embodiment describes an online concrete density detection device for a transport pipeline, comprising a mixer 1, a concrete delivery pump 2, a discharge pipe 3, a return pipe 4, a storage and delivery pipe 5, a three-way valve 6, a first ultrasonic probe 7, a second ultrasonic probe 8, a third ultrasonic probe 9, a pressure transmitter 10, a temperature transmitter 11, a flow transmitter 12, a controller 13, a storage tank 14, a local display 15, a first wireless communication module 16, and a second wireless communication module 17.

[0054] The discharge port of the mixer 1 is connected to the inlet of the concrete pump 2 through a pipeline. One end of the discharge pipe 3 is connected to the discharge port of the concrete pump 2. One end of the return pipe 4 is connected to the inlet of the mixer 1. One end of the storage and conveying pipe 5 is connected to the storage tank 14. The other ends of the discharge pipe 3, the return pipe 4 and the storage and conveying pipe 5 are respectively connected to the three ports of the three-way valve 6.

[0055] The third ultrasonic probe 9 is an ultrasonic transceiver probe. The stirrer 1 is equipped with the third ultrasonic probe 9. The discharge pipe 3 has a horizontal straight pipe section 31. The first ultrasonic probe 7 and the second ultrasonic probe 8 are horizontally and symmetrically installed on the vertical sidewalls at the bends at both ends of the horizontal straight pipe section 31. The measurement accuracy is increased by the propagation of ultrasound in the long straight pipe.

[0056] A pressure transmitter 10, a temperature transmitter 11, and a flow transmitter 12 are sequentially installed on the discharge pipe 3. The agitator 1, the concrete pump 2, the three-way valve 6, the first ultrasonic probe 7, the second ultrasonic probe 8, the third ultrasonic probe 9, the pressure transmitter 10, the temperature transmitter 11, and the flow transmitter 12 are electrically connected to the controller 13. The controller 13 is an STM32 microcontroller. The local display 15 and the first wireless communication module 16 are electrically connected to the controller 13. The second wireless communication module 17 receives the wireless signals transmitted by the first wireless communication module 16.

[0057] Specific Implementation Method Two: Combining Figures 1-4 This embodiment describes an online concrete density detection device for a transportation pipeline, based on specific embodiment one, comprising:

[0058] S1. After the mixer 1 is fed, the concrete is initially mixed. The static concrete density value ρ1 in the mixer 1 is measured by the transmission time of the third ultrasonic probe 9 in the mixer 1. After the static concrete density value ρ1 in the mixer 1 reaches the density requirement, it is transported to the concrete delivery pump 2 through the discharge port of the mixer 1, and then enters the discharge pipe 3. The concrete delivery pump 2 is connected to the frequency converter 19. According to different on-site delivery requirements, the delivery frequency of the concrete delivery pump 2 is changed by the frequency converter 19, thereby changing the pressure value and flow rate value of the concrete in the discharge pipe 3.

[0059] The calculation process for the static concrete density value ρ1 inside the mixer 1 is as follows:

[0060] The relationship between the propagation speed of the ultrasonic wave emitted by the third ultrasonic probe 9 and the density and elastic modulus of the medium is as follows:

[0061]

[0062] In equation (1), c is the propagation speed of the ultrasonic wave emitted by the third ultrasonic probe 9 in the mixer 1, and k is the volume compressibility coefficient of the fresh concrete.

[0063] During the concrete mixing process, mixer 1 rotates axially while the concrete in its radial direction remains relatively stationary. At this time, the relationship between the propagation speed and propagation time of the ultrasonic waves emitted by the third ultrasonic probe 9, using the ultrasonic propagation formula for stationary fluids, is as follows:

[0064]

[0065] In equation (2), d is the propagation distance of the ultrasonic wave emitted by the third ultrasonic probe 9 in the radial propagation section of the stirrer 1, and t3 is the propagation time of the ultrasonic wave emitted by the third ultrasonic probe 9 in the stirrer 1.

[0066] From equations (1) and (2), the static concrete density value ρ1 inside the mixer 1 measured by the third ultrasonic probe 9 is:

[0067]

[0068] S2. During the process of concrete being transported through the discharge pipe 3, the first ultrasonic probe 7 and the second ultrasonic probe 8 are used to measure the dynamic concrete density value ρ2 in the transport pipe based on the forward transmission time t1 and the reverse transmission time t2 of the ultrasonic waves in the discharge pipe 3 containing concrete. The dynamic concrete density value ρ2 in the transport pipe is then transmitted to the local display 15 through the controller 13 for local display.

[0069] The calculation process for the dynamic concrete density value ρ2 inside the transport pipeline is as follows:

[0070] The relationship between the propagation speed of the ultrasonic wave emitted by the first ultrasonic probe 7 and the density and elastic modulus of the medium is as follows:

[0071]

[0072] In equation (4), c0 is the propagation speed of the ultrasonic wave emitted by the first ultrasonic probe 7 in the concrete mixture;

[0073] In the downstream flow, the concrete in the discharge pipe 3 flows from the first ultrasonic probe 7 to the second ultrasonic probe 8. The controller 13 excites the first ultrasonic probe 7 to emit ultrasonic signals. The first ultrasonic probe 7 acts as an ultrasonic transmitting probe, and the second ultrasonic probe 8 acts as an ultrasonic receiving probe. The received ultrasonic echo signals are processed by the controller 13. The relationship between the propagation speed and propagation time of the downstream ultrasonic waves is applicable to the ultrasonic propagation relationship of fluid flowing in the same direction, as shown in the following formula:

[0074]

[0075] In equation (5), d0 is the length of the horizontal straight pipe section 31 between the first ultrasonic probe 7 and the second ultrasonic probe 8, which is the propagation distance of the ultrasonic wave in the horizontal straight pipe section 31, t1 is the propagation time of the ultrasonic wave emitted by the first ultrasonic probe 7 in the pipe along the direction of the concrete flow, and v is the flow velocity of the freshly mixed concrete in the discharge pipe 3.

[0076] In the counter-current flow, the concrete in the discharge pipe 3 flows from the second ultrasonic probe 8 to the first ultrasonic probe 7. The controller 13 excites the second ultrasonic probe 8 to emit ultrasonic signals. The second ultrasonic probe 8 acts as an ultrasonic transmitting probe, and the first ultrasonic probe 7 acts as an ultrasonic receiving probe. The received ultrasonic echo signals are processed by the controller 13. The relationship between the propagation speed and propagation time of the counter-current ultrasonic waves is based on the ultrasonic propagation relationship of the fluid in reverse flow:

[0077]

[0078] In equation (6), t2 is the propagation time of the ultrasonic wave emitted by the second ultrasonic probe 8 in the reverse flow of concrete in the pipe;

[0079] From equations (5) and (6), the sum of the propagation times of ultrasonic waves in the forward and reverse directions in a dynamic concrete pipe is:

[0080]

[0081] Since the propagation speed of ultrasound in concrete is much greater than the flow velocity of concrete in a pipe, equation (7) can be simplified to:

[0082]

[0083] From equations (4) and (8), the dynamic concrete density value ρ2 inside the transport pipeline can be obtained as:

[0084]

[0085] S3. During the process of conveying concrete in the discharge pipe 3, the pressure transmitter 10, temperature transmitter 11 and flow transmitter 12 measure the pressure, temperature and flow rate of the concrete in the discharge pipe 3, and transmit them to the local display 15 through the controller 13 for local display.

[0086] S4. The controller 13 processes the received data values, which include the static concrete density value ρ1 in the mixer 1, the dynamic concrete density value ρ2 in the transport pipeline, the pressure value, the temperature value, and the flow rate value. The controller 13 transmits the received data values ​​to the PC terminal 18 through the first wireless communication module 16 and the second wireless communication module 17.

[0087] S5. The received data values ​​are displayed and change curves are plotted on the LabVIEW interface of the PC terminal 18. The measurement data is stored and the pressure value, temperature value and flow rate value are used as auxiliary references to determine whether the density of the discharge pipe 3 is appropriate.

[0088] S6. Compare the dynamic concrete density value ρ2 in the transport pipeline with the set standard concrete density value. If they match, the concrete is transported to the storage tank 14 or poured directly. If they do not match, proceed to step S7.

[0089] S7. Using PC terminal 18, signals are transmitted to controller 13 via first wireless communication module 16 and second wireless communication module 17. Controller 13 controls three-way valve 6 to switch the concrete flow direction, so that the concrete flows back to mixer 1 through return pipe 4 to remix the concrete. Repeat steps S1-S6 until the dynamic concrete density value ρ2 in the transport pipeline is consistent with the set standard concrete density value.

[0090] Figure 4 The image shows the online concrete density monitoring interface on PC terminal 18. The interface can display the real-time static concrete density value ρ1 in the mixer 1 in the transport pipeline, the dynamic concrete density value ρ2 in the transport pipeline, the pressure value, the temperature value, and the flow rate value. The interface also plots the concrete density change curve, which is used to compare with the required concrete density value to determine whether the degree of concrete mixing meets the standard.

[0091] The data displayed on the online concrete density monitoring interface on the PC terminal 18 is uploaded via the controller 13, the first wireless communication module 16, and the second wireless communication module 17. Based on the concrete density detection results, the control signal of the remote control three-way valve 6 is transmitted down via the first wireless communication module 16, the second wireless communication module 17, and the controller 13. The online monitoring interface also has functions for closing data acquisition, high density alarm, and low density alarm.

[0092] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be permuted and combined. Those skilled in the art can exhaust all possibilities based on the mathematical knowledge of permutation and combination. Therefore, the present invention will not describe the technical solutions after permutation and combination one by one, but it should be understood that the technical solutions after permutation and combination have been disclosed by the present invention.

[0093] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for online detection of concrete density in transport pipelines, characterized in that, include: S1. After the concrete is fed into the mixer (1), it is initially mixed. The static concrete density value inside the mixer (1) is measured by the transmission time of the third ultrasonic probe (9) within the mixer (1). The static concrete density value inside the mixer (1) After reaching the required density, the material is transported through the outlet of the mixer (1) to the concrete pump (2) and then into the discharge pipe (3). S2. During the transportation of concrete through the discharge pipe (3), the dynamic concrete density value in the transportation pipeline is measured using the first ultrasonic probe (7) and the second ultrasonic probe (8) based on the forward transmission time t1 and the reverse transmission time t2 of the ultrasonic waves in the discharge pipe (3) containing concrete. and the dynamic concrete density value in the transport pipeline The data is transmitted to the local display (15) via the controller (13) for local display. S3. During the conveying process of concrete in the discharge pipe (3), the pressure transmitter (10), temperature transmitter (11) and flow transmitter (12) measure the pressure, temperature and flow values ​​of the concrete in the discharge pipe (3) and transmit them to the local display (15) through the controller (13) for local display. S4. The controller (13) processes the received data values, including the static concrete density value inside the mixer (1). Dynamic concrete density value inside the transport pipeline The received data values, including pressure, temperature, and flow rate, are transmitted to the PC terminal (18) via the first wireless communication module (16) and the second wireless communication module (17). S5. The received data values ​​are displayed and change curves are drawn on the LabVIEW interface of the PC terminal (18), and the measurement data is stored. The pressure value, temperature value and flow rate value are used as auxiliary references to determine whether the density of the discharge pipe (3) is appropriate. S6. Dynamic concrete density value in the transport pipeline If the concrete density is compared with the set standard concrete density value, the concrete is transported to the storage tank (14) or poured directly; if the two are inconsistent, proceed to step S7. S7. Using a PC terminal (18), signals are transmitted to the controller (13) via the first wireless communication module (16) and the second wireless communication module (17). The controller (13) controls the three-way valve (6) to switch the concrete flow direction, so that the concrete flows back to the mixer (1) through the return pipe (4) to be remixed. Steps S1-S6 are repeated until the dynamic concrete density value in the transport pipeline is reached. Both are consistent with the set standard concrete density value.

2. The method for online detection of concrete density in a transport pipeline according to claim 1, characterized in that: The concrete pump (2) is connected to a frequency converter (19). The frequency converter (19) changes the conveying frequency of the concrete pump (2), thereby changing the pressure and flow rate of the concrete in the discharge pipe (3).

3. The method for online detection of concrete density in a transport pipeline according to claim 2, characterized in that: The static concrete density value in the mixer (1) mentioned in step S1 The calculation process is as follows: The relationship between the propagation speed of the ultrasonic waves emitted by the third ultrasonic probe (9) and the density and elastic modulus of the medium is as follows: Official (1) In equation (1), c is the propagation speed of the ultrasonic wave emitted by the third ultrasonic probe (9) in the mixer (1), and k is the volume compressibility coefficient of the fresh concrete. The mixer (1) rotates axially during concrete mixing, while the concrete in its radial direction is relatively stationary. At this time, the relationship between the propagation speed and propagation time of the ultrasonic waves emitted by the third ultrasonic probe (9) is based on the ultrasonic propagation relationship of stationary fluids: Official (2) In equation (2), d is the propagation distance of the ultrasonic wave emitted by the third ultrasonic probe (9) in the radial propagation section of the stirrer (1), and t3 is the propagation time of the ultrasonic wave emitted by the third ultrasonic probe (9) in the stirrer (1). From equations (1) and (2), the static concrete density value inside the mixer (1) measured by the third ultrasonic probe (9) can be obtained. for: Official (3).

4. The method for online detection of concrete density in a transport pipeline according to claim 3, characterized in that: The dynamic concrete density value in the transport pipeline mentioned in step S2 The calculation process is as follows: The relationship between the propagation speed of the ultrasonic waves emitted by the first ultrasonic probe (7) and the density and elastic modulus of the medium is as follows: Official (4) In equation (4), c0 is the propagation speed of the ultrasonic wave emitted by the first ultrasonic probe (7) in the concrete mixture; In the downstream flow, the concrete in the discharge pipe (3) flows from the first ultrasonic probe (7) to the second ultrasonic probe (8). The controller (13) excites the first ultrasonic probe (7) to emit ultrasonic signals. The first ultrasonic probe (7) acts as an ultrasonic transmitting probe, and the second ultrasonic probe (8) acts as an ultrasonic receiving probe. The received ultrasonic echo signals are processed by the controller (13). The relationship between the propagation speed and propagation time of the downstream ultrasonic waves is applicable to the ultrasonic propagation relationship of fluid flowing in the same direction. The formula is as follows: Official (5) In equation (5), d0 is the length of the horizontal straight pipe section (31) between the first ultrasonic probe (7) and the second ultrasonic probe (8), which is the propagation distance of the ultrasonic wave in the horizontal straight pipe section (31), t1 is the propagation time of the ultrasonic wave emitted by the first ultrasonic probe (7) in the pipe along the concrete flow, and v is the flow velocity of the freshly mixed concrete in the discharge pipe (3). In the countercurrent flow, the concrete in the discharge pipe (3) flows from the second ultrasonic probe (8) to the first ultrasonic probe (7). The controller (13) excites the second ultrasonic probe (8) to emit ultrasonic signals. The second ultrasonic probe (8) acts as an ultrasonic transmitting probe, and the first ultrasonic probe (7) acts as an ultrasonic receiving probe. The received ultrasonic echo signals are processed by the controller (13). The relationship between the propagation speed and propagation time of the countercurrent ultrasonic waves is applicable to the ultrasonic propagation relationship of the fluid in reverse flow as follows: Official (6) In equation (6), t2 is the propagation time of the ultrasonic wave emitted by the second ultrasonic probe (8) in the reverse flow of concrete in the pipe; From equations (5) and (6), the sum of the propagation times of ultrasonic waves in the forward and reverse directions in a dynamic concrete pipe is: Official (7) Since the propagation speed of ultrasound in concrete is much greater than the flow velocity of concrete in a pipe, equation (7) can be simplified to: Official (8) From equations (4) and (8), the dynamic concrete density value inside the transport pipeline can be obtained. for: Official (9).

5. The online concrete density detection device for a transport pipeline used in the online concrete density detection method for a transport pipeline according to claim 1, characterized in that: The system includes a mixer (1), a concrete pump (2), a discharge pipe (3), a return pipe (4), a storage and conveying pipe (5), a three-way valve (6), a first ultrasonic probe (7), a second ultrasonic probe (8), a third ultrasonic probe (9), a pressure transmitter (10), a temperature transmitter (11), a flow transmitter (12), a controller (13), and a storage tank (14). The discharge port of the mixer (1) is connected to the inlet of the concrete pump (2), one end of the discharge pipe (3) is connected to the discharge port of the concrete pump (2), one end of the return pipe (4) is connected to the inlet of the mixer (1), and one end of the storage and conveying pipe (5) is connected to the storage tank (14). The discharge pipe (3), the return pipe (4), and the storage and conveying pipe (5) are connected together. The other ends of the three are respectively connected to the three ports of the three-way valve (6). The agitator (1) is equipped with a third ultrasonic probe (9). The discharge pipe (3) has a horizontal straight pipe section (31). The first ultrasonic probe (7) and the second ultrasonic probe (8) are horizontally and symmetrically installed on the side walls of the two ends of the horizontal straight pipe section (31). The discharge pipe (3) is sequentially equipped with a pressure transmitter (10), a temperature transmitter (11) and a flow transmitter (12). The agitator (1), the concrete pump (2), the three-way valve (6), the first ultrasonic probe (7), the second ultrasonic probe (8), the third ultrasonic probe (9), the pressure transmitter (10), the temperature transmitter (11) and the flow transmitter (12) are electrically connected to the controller (13).

6. The online concrete density detection device for transportation pipelines according to claim 5, characterized in that: It also includes a local display (15), a first wireless communication module (16) and a second wireless communication module (17). The local display (15) and the first wireless communication module (16) are electrically connected to the controller (13) respectively, and the second wireless communication module (17) receives the wireless signal transmitted by the first wireless communication module (16).

7. The online concrete density detection device for transportation pipelines according to claim 6, characterized in that: The third ultrasonic probe (9) is an ultrasonic transceiver probe.

8. The online concrete density detection device for transportation pipelines according to claim 7, characterized in that: The controller (13) is an STM32 microcontroller.

Images