Ferromagnetic aggregate concrete segregation control device and method

Abstract

The invention relates to a ferromagnetic aggregate concrete segregation control device and method.The ferromagnetic aggregate concrete segregation control device comprises an electromagnet, a range finder, a lifting device, a control system and an arm frame, the upper end of the arm frame is connected with the electromagnet, the lower end of the arm frame is connected with a base, the control system and the lifting device are arranged on the arm frame, and the control system can control the electromagnet, the range finder and the lifting device; and the control system controls the magnetic field intensity of the electromagnet by controlling the magnitude of the current, receives and processes data of the range finder, and sends an instruction to lift the lifting device. According to the device, uniform pouring of heavy concrete is achieved by controlling sedimentation of ferromagnetic aggregate, and therefore the radiation shielding function of the structure is guaranteed.

Description

Technical Field

[0001] The present invention belongs to the technical field of building construction, and particularly relates to a device and method for controlling the segregation of ferromagnetic aggregate concrete. Background Art

[0002] In the construction of facilities such as nuclear power plants, the concrete structure is an important part of the ionization radiation shielding layer. For the gamma rays generated by nuclear reactions, the radiation shielding performance can be effectively improved by increasing the mass density of the shielding material. By replacing ordinary concrete aggregates with aggregates having a higher density (such as barite, magnetite, steel shots, etc.), a concrete material with a relatively high average density can be obtained, which is usually called "heavy concrete". At present, heavy concrete has been widely used in the construction of radiation shielding structures in nuclear-related projects. However, a major problem in the application of this material is that during the structural construction stage, since the aggregate density is greater than that of the surrounding slurry, it is easy to settle, resulting in concrete segregation, damaging the overall uniformity of the material, and thus affecting the radiation shielding function of the structure.

[0003] Therefore, how to provide a device and method for controlling the segregation of ferromagnetic aggregate concrete is a technical problem that those skilled in the art urgently need to solve. Summary of the Invention

[0004] The present invention provides a device and method for controlling the segregation of ferromagnetic aggregate concrete, which realizes the uniform pouring of heavy concrete by controlling the settlement of ferromagnetic aggregates.

[0005] To solve the above technical problems, the present invention includes the following technical solutions:

[0006] A device for controlling the segregation of ferromagnetic aggregate concrete includes an electromagnet, a rangefinder, a lifting device, a control system, and a boom. The upper end of the boom is connected to the electromagnet, and the lower end is connected to the base. The control system and the lifting device are arranged on the boom. The control system can control the electromagnet, the rangefinder, and the lifting device. The control system controls the magnetic field intensity of the electromagnet by controlling the magnitude of the current, and receives and processes the data of the rangefinder, and issues an instruction to lift or lower the lifting device.

[0007] Further, the rangefinder is a laser rangefinder.

[0008] Further, the lifting device is a hydraulic lifting device.

[0009] The present invention also provides a method for controlling the segregation of ferromagnetic aggregate concrete, including the following steps:

[0010] Step S1. Obtain control parameters through experiments: First, keep the electromagnet off, and measure the gravity of ferromagnetic aggregate within the magnetic range below the electromagnet using a diamagnetic dynamometer. Then, start the electromagnet, gradually increase the current from zero, and record the relationship curve between the readings of the diamagnetic dynamometer and the current. Using standard tests, measure the mass densities ρ 骨料 and ρ 浆体 of the ferromagnetic aggregate and the slurry respectively, and derive the magnitude of the current I 平衡 when the ferromagnetic aggregate is in equilibrium in the concrete; measure the initial setting time T 初凝 and the final setting time T 终凝 of the concrete;

[0011] Step S2. Control the settlement of ferromagnetic aggregate during pouring. During the construction stage of the radiation shielding structure, first measure the distance between the electromagnet and the bottom of the formwork using a rangefinder, send a lifting command to the lifting device through the control system, and adjust the height of the electromagnet and its distance from the bottom of the formwork. Pour the heavy concrete with ferromagnetic aggregate into the cavity formed by the formwork, start the electromagnet and keep the current magnitude at I 平衡 ; as the pouring liquid level of the heavy concrete rises, lift the electromagnet upward to keep the distance between the electromagnet and the concrete liquid level at H;

[0012] Step S3: Keep the magnetic force for a period of time after pouring: After completing the pouring of this part of the structure, continue to keep the electromagnet in the state with current I 平衡 and the height H from the upper surface of the structure, and maintain it for T 初凝 until the concrete starts to set; thereafter, linearly decrease the current at a rate of I 平衡 / (T 终凝 -T 初凝 ) for a time of T 终凝 -T 初凝 until the concrete reaches the final setting state; at this time, the current drops to zero, turn off the electromagnet, and the device completes its work.

[0013] Furthermore, when the ferromagnetic aggregate is in equilibrium, F 磁 =(ρ 骨料 -ρ 浆体 )gV, where ρ 骨料 is the mass density of the ferromagnetic aggregate, g is the acceleration due to gravity, V is the volume of the ferromagnetic aggregate, ρ 浆体 is the mass density of the slurry, and F 磁 is the magnitude of the magnetic force exerted on the ferromagnetic aggregate in the magnetic field.

[0014] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0015] The present invention provides a segregation control device and method for ferromagnetic aggregate concrete, which utilizes a magnetic field to counteract the sinking tendency of ferromagnetic aggregates in concrete. The segregation control device for ferromagnetic aggregate concrete includes an electromagnet, a rangefinder, a lifting device, and a control system. The upper end of the boom is connected to the electromagnet, and the lower end is connected to the base. The control system and the lifting device are arranged on the boom. The control system can control the electromagnet, the rangefinder, and the lifting device. The control system controls the magnetic field intensity of the electromagnet by controlling the magnitude of the current, receives and processes the data of the rangefinder, and issues instructions to lift or lower the lifting device. This device realizes the uniform pouring of heavy concrete by controlling the settlement of ferromagnetic aggregates, thereby ensuring the radiation shielding function of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the force balance state of ferromagnetic aggregates in a segregation control method for ferromagnetic aggregate concrete according to an embodiment of the present invention;

[0017] Figure 2 It is a schematic structural diagram of a segregation control device for ferromagnetic aggregate concrete according to an embodiment of the present invention;

[0018] Figure 3 It is a schematic diagram of a segregation control device for ferromagnetic aggregate concrete according to an embodiment of the present invention for measuring the suction force of the electromagnet on ferromagnetic aggregates;

[0019] Figure 4 It is a schematic diagram of a segregation control device for ferromagnetic aggregate concrete according to an embodiment of the present invention for measuring the control of aggregate settlement during the pouring of heavy concrete.

[0020] In the figure:

[0021] 11 - Electromagnet, 12 - Rangefinder, 13 - Lifting device, 14 - Control system, 15 - Boom, 16 - Base; 2 - Diamagnetic dynamometer; 3 - Aggregate; 4 - Formwork; 5 - Heavy concrete. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] The following further describes in detail a segregation control device and method for ferromagnetic aggregate concrete provided by the present invention with reference to the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the accompanying drawings are all in a very simplified form and use non-precise scales, only for conveniently and clearly assisting in explaining the purpose of the embodiments of the present invention. For the convenience of description, the "upper" and "lower" described below are in the same direction as the upper and lower of the accompanying drawings, but this cannot be a limitation to the technical solution of the present invention.

[0023] Embodiment 1

[0024] The following combination Figures 1 to 4, the structural composition of the segregation control device for ferromagnetic aggregate concrete of the present invention will be described in detail.

[0025] The segregation control device for ferromagnetic aggregate concrete includes an electromagnet 11, a rangefinder 12, a lifting device 13, a control system 14, and a boom 15. The upper end of the boom 15 is connected to the electromagnet 11, and the lower end is connected to the base 16. The control system 14 and the lifting device 13 are arranged on the boom 15. The control system 14 can control the electromagnet 11, the rangefinder 12, and the lifting device 13. The control system 14 controls the magnetic field intensity of the electromagnet 11 by controlling the magnitude of the current, and receives and processes the data of the rangefinder 12, and issues an instruction to lift or lower the lifting device 13.

[0026] This embodiment provides a method for generating a magnetic field by an electromagnet to avoid the settlement of ferromagnetic aggregates in newly poured heavy concrete. Its basic principle lies in using the magnetic field to offset the sinking trend of ferromagnetic aggregates in the concrete. As Figure 1 shown, the concrete mixture is composed of aggregates and paste. The gravity acting on the aggregates vertically downward is G = ρ 骨料 gV (ρ 骨料 is the mass density of the aggregates, g is the acceleration due to gravity, and V is the volume of the aggregates); the buoyancy acting on the aggregates upward is F 浮 = ρ 浆体 gV (ρ 浆体 is the mass density of the paste); the magnetic force acting on the aggregates in the magnetic field is denoted as F 磁 . If F 浮 + F 磁 = G, that is

[0027] F 磁 = (ρ 骨料 - ρ 浆体 )gV (1)

[0028] then the aggregates are in a state of force balance.

[0029] (1) For a certain ferromagnetic aggregate (such as steel shot or magnetite), through experiments, obtain the variation law of the magnetic suction force it receives with the increase of current at a specific height H from the electromagnet (generally, the value of H is the height of the radiation shielding structure, such as H = 5m).

[0030] As Figure 3 shown, during the measurement, first, the electromagnet 11 is in the off state, and the gravity of the aggregates 3, F2 = G, is measured through the reading of the diamagnetic type dynamometer 2. Then, start the electromagnet 11, and gradually increase the current I from zero. Correspondingly, the magnetic suction force F of the electromagnet 11 on the aggregates 3 磁It gradually increases from zero. At the same time, the reading F2 of the diamagnetic dynamometer 2 gradually decreases from the initial value G until it drops to zero. Record the relationship curve F2(I) between the dynamometer reading and the current during this process. From

[0031] F2 + F 磁 = G, the variation curve of the suction force of the electromagnet 11 on the aggregate 3 with respect to the current can be obtained

[0032] F 磁 (I) = G - F2(I) (2)

[0033] A method for controlling the segregation of ferromagnetic aggregate concrete includes the following steps:

[0034] Step S1, obtaining control parameters through experiments: First, keep the electromagnet 11 in the off state, and measure the gravity of the ferromagnetic aggregate 3 within the magnetic range below the electromagnet 11 using a diamagnetic dynamometer 2; then start the electromagnet 11, gradually increase the current from zero, and record the relationship curve between the reading of the diamagnetic dynamometer 2 and the current; using standard tests, measure the mass densities ρ 骨料 and ρ 浆体 of the ferromagnetic aggregate and the paste respectively, and deduce the current magnitude I 平衡 when the ferromagnetic aggregate is in an equilibrium state in the concrete; measure the initial setting time T 初凝 and the final setting time T 终凝 of the concrete;

[0035] Step S2, controlling the settlement of ferromagnetic aggregate during pouring. During the construction stage of the radiation shielding structure, first measure the distance between the electromagnet and the bottom of the formwork using a rangefinder 12, send a lifting command to the lifting device 13 through the control system 14, and adjust the height of the electromagnet and the distance H from the bottom of the formwork; pour the heavy concrete 5 of the ferromagnetic aggregate into the cavity formed by the formwork enclosure, start the electromagnet 11 and keep the current magnitude at I 平衡 ; as the pouring liquid level of the heavy concrete rises, lift the electromagnet upward to keep the distance between the electromagnet 11 and the liquid level of the heavy concrete 5 at H;

[0036] Step S3: Keep the magnetic force for a period of time after pouring: After pouring this part of the structure, continue to keep the electromagnet in the state of current I 平衡 and the height H from the upper surface of the structure, and continue for T 初凝 until the concrete starts to set; thereafter, linearly decrease the current at a rate of I 平衡 / (T 终凝 - T 初凝 ), and after a time of T 终凝 - T 初凝 , the concrete reaches the final setting state; at this time, the current drops to zero, turn off the electromagnet 11, and the device finishes working.

[0037] The above examples are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above examples. The above-described examples only represent several embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several variations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A device for controlling segregation of ferromagnetic aggregate concrete, characterized in that, It includes an electromagnet, a rangefinder, a lifting device, a control system and a boom. The upper end of the boom is connected to the electromagnet, and the lower end is connected to the base. The control system and the lifting device are arranged on the boom. The control system can control the electromagnet, the rangefinder and the lifting device. The control system controls the magnetic field strength of the electromagnet by controlling the magnitude of the current, and receives and processes the data of the rangefinder, and issues an instruction to lift or lower the lifting device.

2. The segregation control device for ferromagnetic aggregate concrete according to claim 1, characterized in that The rangefinder is a laser rangefinder.

3. The segregation control device for ferromagnetic aggregate concrete according to claim 1, characterized in that, The lifting device is a hydraulic lifting device.

4. A method for controlling the segregation of ferromagnetic aggregate concrete, characterized in that, It includes the following steps: Step S1. Obtain control parameters through experiments: First, keep the electromagnet in the off state, and measure the gravity of ferromagnetic aggregates within the magnetic range below the electromagnet using a diamagnetic dynamometer. Then, start the electromagnet, gradually increase the current from zero, and record the relationship curve between the readings of the diamagnetic dynamometer and the current. Using standard tests, measure the mass densities ρ 骨料 and ρ 浆体 of ferromagnetic aggregates and paste respectively, and deduce the current magnitude I 平衡 when the ferromagnetic aggregates are in an equilibrium state in the concrete. Measure the initial setting time T 初凝 and final setting time T 终凝 of the concrete; Step S2: Control the settlement of ferromagnetic aggregates during pouring. During the construction stage of the radiation shielding structure, first measure the distance between the electromagnet and the bottom of the formwork with a rangefinder, send a lifting command to the lifting device through the control system, and adjust the height of the electromagnet and the distance from the bottom of the formwork; pour the heavy concrete with ferromagnetic aggregates into the cavity formed by the formwork enclosure, start the electromagnet and keep the current magnitude at I 平衡 ; as the liquid level of the heavy concrete pouring rises, lift the electromagnet upward so as to keep the distance between the electromagnet and the concrete liquid level at H; Step S3: Maintain the magnetic force for a period of time after pouring: After pouring this part of the structure, continue to keep the electromagnet in a state with current I 平衡 and height H from the upper surface of the structure for a duration of T 初凝 until the concrete starts to set; thereafter, linearly decrease the current at a rate of I 平衡 / (T 终凝 - T 初凝 ), and after a time of T 终凝 - T 初凝 , the concrete reaches the final setting state; at this time, the current drops to zero, turn off the electromagnet, and the device completes its operation.

5. The method according to claim 4, wherein When the ferromagnetic aggregate is in balance, F 磁 = (ρ 骨料 - ρ 浆体 )gV, where ρ 骨料 is the mass density of ferromagnetic aggregate, g is the acceleration due to gravity, V is the volume of ferromagnetic aggregate, and ρ 浆体 is the mass density of the slurry. F 磁 is the magnitude of the magnetic force exerted on the ferromagnetic aggregate in the magnetic field.

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