Concrete crushing and screening device and recycled asphalt concrete production process

Abstract

The invention belongs to the technical field of crushing equipment, and particularly provides a concrete crushing and screening device and a recycled asphalt concrete production process. The concrete crushing and screening device comprises a multi-stage vibrating screen, a first-stage crusher and a second-stage crusher, and the multi-stage vibrating screen can screen concrete materials into at least three types according to the particle size in advance. In the working process, powder materials which do not need to be crushed repeatedly are directly discharged through the corresponding discharging ports and do not enter the first-stage crusher and the second-stage crusher any more, energy consumption is reduced, and excessive crushing is avoided. Coarse aggregate with large particle size firstly enters the primary crusher through the corresponding discharge port, and then enters the secondary crusher through the discharge channel for secondary crushing. The graded crushing design ensures that the coarse aggregate is fully crushed, the mixing of substandard aggregate or powder materials in a final product is reduced, and the grading uniformity of the recycled aggregate and the quality stability of the product are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of crushing equipment, and particularly relates to a concrete crushing and screening device and a production process of recycled asphalt concrete. BACKGROUND

[0002] During the maintenance or demolition of a building or a road, a large amount of concrete waste is generated. In order to realize the resource utilization of the concrete waste, the concrete waste can be crushed into aggregates and used for the production of recycled asphalt concrete.

[0003] In the recycling process of the concrete waste, the crushing and screening of the concrete are crucial preprocessing steps, which need to crush the concrete with different sizes into aggregates with appropriate particle sizes. The conventional preprocessing process adopts the sequence of crushing first and then screening, that is, the concrete material is first crushed by a crusher, and then separated into aggregates with different particle sizes by a vibrating screen according to the particle size specifications.

[0004] The above-mentioned crushing and screening method for concrete, although simple in structure and widely used, has the following disadvantages: on the one hand, since the particle size range of the material before crushing is extremely wide, the crusher needs to process all the materials from powder to large blocks, and the working parameters of the crusher can only be set by compromise according to the average working condition, and cannot be optimized for specific particle sizes. This leads to that the fine aggregate that has met the requirements is subjected to high-intensity impact and extrusion with the coarse aggregate in the crushing cavity, not only causing invalid consumption of energy, but also causing excessive crushing of the fine material, resulting in a large number of powdery materials. In actual production of recycled asphalt concrete, the old asphalt mixture needs to maintain a certain particle size distribution, and if it is completely pulverized into powder, the effective skeleton structure cannot be formed, which affects the mechanical properties and construction performance of the recycled asphalt concrete. Secondly, for the coarse aggregate with a large size, the single crushing is insufficient, which leads to that part of the aggregate that does not meet the target particle size is still mixed in the final product, affecting the uniformity of the particle size distribution and the stability of the product quality of the recycled aggregate. SUMMARY

[0005] Based on the above technical problems, the application provides a concrete crushing and screening device and a production process of recycled asphalt concrete to solve the technical problem that the crushing device of the prior art is prone to produce a large number of powdery materials that cannot be used.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the application is as follows: In a first aspect, the application provides a concrete crushing and screening device, comprising: a multi-stage vibrating screen for screening the material into at least three kinds according to the particle size, the multi-stage vibrating screen having at least three discharge ports for discharging coarse aggregate, fine aggregate and powdery material, respectively; at least one primary crusher having a top end for feeding and being in communication with the discharge port for discharging coarse aggregates, and a bottom end for discharging and being provided with two discharge channels and a discharge control mechanism for controlling the opening or closing of the two discharge channels respectively; and at least one secondary crusher having a top end for feeding and being in communication with the discharge port for discharging fine aggregates and one of the discharge channels.

[0007] In one possible implementation, the multi-stage vibrating screen comprises: a screen box horizontally arranged and internally provided with a receiving cavity, a bottom of the receiving cavity being arranged to be inclined downward in a discharging direction, a top of one end of the screen box being provided with a feeding port, and a bottom of another end of the screen box being provided with the discharge port; and at least two screening units arranged in the receiving cavity in a spaced-apart manner, the screening units being arranged to be inclined downward in the discharging direction and located above the corresponding discharge ports, and the screening units being arranged in a decreasing order of mesh diameter from top to bottom.

[0008] In one possible implementation, the concrete crushing and screening device further comprises a feeding elevator configured to feed materials to the feeding end of the multi-stage vibrating screen.

[0009] In one possible implementation, the primary crusher is configured such that a lower surface of the primary crusher for forming the discharge channels is in a circular arc shape, and the discharge control mechanism comprises: a discharge valve plate in an arc shape and rotationally fitted with the lower surface of the primary crusher, the discharge valve plate being provided with a closed state of covering the outlets of the two discharge channels simultaneously and an open state of being rotated to cover only the outlet of one of the discharge channels; and a discharge driving member arranged in the primary crusher and configured to drive the discharge valve plate to switch between the closed state and the open state.

[0010] In one possible implementation, the secondary crusher is provided with two working areas arranged along a long axis direction of the secondary crusher, and one of the working areas is located below the discharge port for discharging fine aggregates. The concrete crushing and screening device further comprises a horizontal feeder arranged between the primary crusher and the secondary crusher and configured to feed materials discharged by the corresponding discharge channels to another working area of the secondary crusher.

[0011] In one possible implementation, the horizontal feeder is a screw conveyor arranged parallel to the long axis of the secondary crusher, with the feed end of the screw conveyor located below the corresponding discharge channel, and the bottom of the other end provided with a first guide pipe communicating with the top of the secondary crusher.

[0012] In one possible implementation, a second guide pipe is provided between the top of the secondary crusher and the discharge port corresponding to the multi-stage vibrating screen, and the second guide pipe is a tortuous pipe.

[0013] In one possible implementation, the primary crusher includes: The outer shell has a crushing chamber, the top of which is connected to the corresponding discharge port, and the bottom of which has two discharge channels. A crushing roller is rotatably disposed in the crushing chamber in the horizontal direction, and crushing channels are formed between the crushing roller and the two side walls of the crushing chamber respectively. An impact block is disposed within the crushing chamber and positioned above the crushing roller; and A lifting mechanism, located in the outer casing, is used to drive the impact block to move up and down.

[0014] In one possible implementation, the impact block includes an impact portion and a connecting portion. The impact portion is disposed inside the crushing chamber and located above the crushing roller. The connecting portion is connected to the top of the impact portion and slides in cooperation with the outer shell. The lifting mechanism includes: A lifting wheel, located on one side of the connecting portion and rotatably engaged with the housing, has a connected state (contacting the connecting portion) and a disengaged state (detached from the connecting portion) during rotation. A lifting drive component is used to drive the lifting wheel to rotate about its own axis.

[0015] Compared with the prior art, the advantages of the concrete crushing and screening device provided in this application are: The concrete crushing and screening device provided in this application includes a multi-stage vibrating screen, a primary crusher, and a secondary crusher. The multi-stage vibrating screen can pre-sort concrete materials into at least three particle sizes. During operation, powdery materials that do not require repeated crushing are directly discharged through their corresponding outlets, avoiding further entry into the primary and secondary crushers, thus reducing energy consumption and preventing over-crushing. Larger coarse aggregates first enter the primary crusher through their corresponding outlets, and then enter the secondary crusher through the discharge channel for secondary crushing. This graded crushing design ensures that coarse aggregates are fully crushed, reducing the mixing of substandard aggregates in the final product and improving the gradation uniformity and product quality stability of recycled aggregates. The primary crusher has two discharge channels at its bottom. When larger coarse aggregates are needed as raw materials for recycled asphalt, a portion of the coarse aggregates can be discharged directly from the corresponding discharge channels without undergoing secondary crushing, meeting the requirements for recycled asphalt concrete raw materials. Smaller fine aggregates enter the secondary crusher through their corresponding outlets, are crushed by the secondary crusher, and do not re-enter the primary crusher. This avoids fine aggregates from being subjected to high-intensity impact and compression together with coarse aggregates in the crushing chamber, reducing the over-crushing of fine aggregates and decreasing the amount of powdery material generated.

[0016] The concrete crushing and screening device provided in this application adopts a combined design of a multi-stage vibrating screen, a primary crusher, and a secondary crusher. This allows the device to adapt to concrete waste with different particle size compositions and directly discharge the coarse aggregate required for recycled asphalt production through the discharge channel and discharge control mechanism. This helps to achieve reasonable control of the output of coarse and fine aggregates. The primary and secondary crushers crush materials of different particle sizes respectively, which can avoid over-crushing of materials, ensure the uniformity of aggregate gradation required for recycled asphalt concrete, and thus ensure the quality stability of recycled asphalt concrete products.

[0017] Secondly, this application provides a recycled asphalt concrete production process, which uses the concrete crushing and screening device described in any of the above implementations to crush concrete materials, and has the same technical effect, which will not be elaborated here. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 Schematic diagram of the concrete crushing and screening device provided in this application Figure 1 ; Figure 2 Schematic diagram of the concrete crushing and screening device provided in this application Figure 2 ; Figure 3 This is a schematic diagram of the structure of the primary crusher, secondary crusher, and horizontal feeder in this application. Figure 1 ; Figure 4 This is a schematic diagram of the structure of the primary crusher, secondary crusher, and horizontal feeder in this application. Figure 2 ; Figure 5 This is a partially enlarged view of the bottom discharge control mechanism of the primary crusher in this application; Figure 6 This is an exploded view of the assembly of the bottom discharge control mechanism of the primary crusher in this application; Figure 7 This is a schematic diagram of the structure of the secondary crusher and the horizontal feeder in this application; Figure 8 This is an internal sectional view of the primary crusher in this application; Figure 9 This is a structural diagram illustrating one implementation of the lifting mechanism and lifting block in this application; Figure 10 This is a structural diagram of another implementation of the lifting mechanism and lifting block in this application; Explanation of reference numerals in the attached figures: 10. Multi-stage vibrating screen; 11. Discharge port; 20. Primary crusher; 21. Outer shell; 211. Discharge channel; 22. Crushing roller; 23. Impact block; 231. Impact part; 232. Connecting part; 24. Lifting mechanism; 241. Lifting wheel; 25. Discharge control mechanism; 251. Discharge valve plate; 252. Discharge drive component; 30. Secondary crusher; 31. Second guide pipe; 40. Feeding elevator; 41. Feeding hopper; 42. Feeding conveying mechanism; 50. Horizontal feeder; 51. First guide pipe. Detailed Implementation

[0020] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0021] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0022] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" or "several" means two or more, unless otherwise explicitly specified.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0025] Please refer to the following: Figures 1 to 10 The following describes the concrete crushing and screening device and the recycled asphalt concrete production process provided in the embodiments of this application.

[0026] Please see Figures 1 to 6 In one aspect, embodiments of this application provide a concrete crushing and screening device, including a multi-stage vibrating screen 10, a primary crusher 20, and a secondary crusher 30.

[0027] The multi-stage vibrating screen 10 is used to separate materials into at least three types according to particle size. The multi-stage vibrating screen 10 has at least three discharge ports 11, used to discharge at least one type of coarse aggregate (e.g., materials with particle sizes of 5-8cm and 8-12cm), at least one type of fine aggregate (e.g., materials with particle sizes of 0.1-0.5cm and 0.5-5cm), and powder materials with even smaller particle sizes. The number of primary crushers 20 corresponds to the type of coarse aggregate, and the number of secondary crushers 30 corresponds to the type of fine aggregate.

[0028] Powdered materials do not require further crushing and can be directly discharged from the multi-stage vibrating screen 10 through the corresponding discharge port 11. The top of the primary crusher 20 is the feed end, which is connected to the discharge port 11 for discharging coarse aggregate. The bottom of the primary crusher 20 is the discharge end, and it is equipped with two discharge channels 211 and a discharge control mechanism 25 for controlling the opening and closing of the two discharge channels 211 respectively. The top of the secondary crusher 30 is the feed end, which is connected to the discharge port 11 for discharging fine aggregate and one of the discharge channels 211. The bottom of the secondary crusher 30 is the discharge end. To allow the material from the primary crusher 20 to enter the secondary crusher 30 through the corresponding discharge channel 211, the secondary crusher 30 can be located below the primary crusher 20 in the height direction.

[0029] When the height of the feed end of the secondary crusher 30 is higher than the height of the discharge end of the primary crusher 20, an additional lifting device is required to transport the material discharged from the primary crusher 20 to the secondary crusher 30.

[0030] In one specific embodiment, when the coarse aggregate separated by the multi-stage vibrating screen 10 has two particle size specifications, 5-8cm and 8-12cm, two primary crushers 20 are correspondingly set, and the crushing parameters of the two primary crushers 20 are designed according to the corresponding material particle size. If the particle size difference between the two coarse aggregates after crushing is small, they can enter the same secondary crusher 30 for secondary crushing. When the difference is large, the discharge ports 11 of the two primary crushers 20 can be connected to two secondary crushers 30 of different specifications respectively. It is understood that, without violating the working principle and usage of the embodiments of this application, users can adjust the specific parameters, quantity, and connection method of the primary crusher 20 and the secondary crusher 30 according to actual needs.

[0031] Compared with the prior art, the beneficial effects of the concrete crushing and screening device provided in this application are: The concrete crushing and screening device provided in this application includes a multi-stage vibrating screen 10, a primary crusher 20, and a secondary crusher 30. The multi-stage vibrating screen 10 can pre-sort concrete materials into at least three types according to particle size. During operation, powdery materials that do not require repeated crushing are directly discharged through the corresponding discharge port 11, without entering the primary crusher 20 and the secondary crusher 30, reducing energy consumption and avoiding over-crushing. Larger coarse aggregates first enter the primary crusher 20 through the corresponding discharge port 11, and then enter the secondary crusher 30 through the discharge channel 211 for secondary crushing. This graded crushing design ensures that the coarse aggregates are fully crushed, reducing the mixing of substandard aggregates in the final product and improving the gradation uniformity and product quality stability of recycled aggregates. The primary crusher 20 has two discharge channels 211 at its bottom. When it is necessary to add larger coarse aggregates as raw materials for recycled asphalt, a portion of the coarse aggregates can be discharged directly from the corresponding discharge channel 211 without secondary crushing through the discharge control mechanism 25, meeting the requirements for recycled asphalt concrete raw materials. Fine aggregates with smaller particle sizes enter the secondary crusher 30 through the corresponding discharge port 11, where they are crushed and do not enter the primary crusher 20. This avoids the fine aggregates from being subjected to high-intensity impact and compression together with the coarse aggregates in the crushing chamber, reducing the over-crushing of fine aggregates and decreasing the amount of powdery material generated.

[0032] The concrete crushing and screening device provided in this application adopts a combined design of a multi-stage vibrating screen 10, a primary crusher 20, and a secondary crusher 30. This allows the device to adapt to concrete waste with different particle size compositions and directly discharge the coarse aggregate required for recycled asphalt production through the discharge channel 211 and the discharge control mechanism 25. This helps to achieve reasonable control of the output of coarse and fine aggregates. The primary crusher 20 and the secondary crusher 30 crush materials of different particle sizes respectively, which can avoid over-crushing of materials, ensure the uniformity of aggregate gradation required for recycled asphalt concrete, and thus ensure the quality stability of recycled asphalt concrete products.

[0033] The multi-stage vibrating screen 10 employs two or more layers of screens, capable of separating materials into at least three categories. Taking a three-layer screen as an example, the upper screen has a screen aperture diameter of 10cm (for separating the first coarse aggregate), the middle screen has a screen aperture diameter of 5cm (for separating the second coarse aggregate), and the lower screen has a screen aperture diameter of 2mm (for separating fine aggregate). Powder materials smaller than 2mm pass through the lower screen and fall to the bottom of the vibrating screen cavity, and are directly discharged through the lowest discharge port 11. Each of the upper, middle, and lower screens corresponds to a discharge port 11, and each discharge port 11 is equipped with a crusher designed for the particle size of that aggregate. The crusher can perform targeted crushing, improving the uniformity of crushing. It should be noted that the above parameters are only an example of one feasible implementation method of this application and are not a limitation thereof. In actual use, users can set the number of screens and the diameter of the screen apertures according to actual production needs.

[0034] Considering that both coarse and fine aggregates are needed in the production of recycled asphalt concrete, the coarse aggregates crushed by the primary crusher 20 can be directly discharged through one of the discharge channels 211 and used as raw materials for recycled asphalt concrete. Alternatively, they can enter the next-stage secondary crusher 30 through the other discharge channel 211, where they are crushed into smaller aggregates. The discharge control mechanism 25 controls the opening and closing of the two discharge channels 211. The discharge control mechanism 25 can use existing discharge control valves, driven by pneumatic, hydraulic, or electric means, such as a pneumatic gate valve, which offers fast response and facilitates automated control.

[0035] The primary crusher 20 is specifically designed for processing coarse aggregates, and its crushing parameters (such as speed, pressure, and crushing gap) can be optimized automatically based on the actual material conditions. The primary crusher 20 can be any existing type, such as a jaw crusher or roller crusher. Its feed end is connected to the coarse aggregate discharge port 11 of the multi-stage vibrating screen 10 via a flange connection or a bellows connection.

[0036] The secondary crusher 30 performs fine crushing of fine aggregates and some coarse aggregates to ensure that the aggregate gradation meets the requirements of recycled asphalt concrete. The secondary crusher 30 can be a cone crusher, a fine jaw crusher, or a roller crusher. The secondary crusher 30 has two feed ends, which are respectively connected to the fine aggregate discharge port 11 of the multi-stage vibrating screen 10 and one of the discharge channels 211 of the primary crusher 20. The secondary crusher 30 is typically located below the primary crusher 20 in height, allowing the material crushed by the primary crusher 20 to enter the secondary crusher 30 by gravity.

[0037] This embodiment of the application uses a multi-stage vibrating screen 10 to pre-screen materials, allowing the primary crusher 20 to focus on processing coarse aggregates, while the secondary crusher 30 processes fine aggregates and the material remaining after primary crushing. This solves the problem of over-crushing of fine aggregates in the primary crusher 20, resulting in powder, while ensuring that coarse aggregates are fully crushed. This improves the gradation uniformity and product quality of recycled aggregates, reduces energy waste, and meets the stringent requirements for aggregate gradation in recycled asphalt concrete production.

[0038] In some possible embodiments, the multi-stage vibrating screen 10 includes a screen box and at least two screening units. The screen box is horizontally arranged and has a receiving cavity inside. The bottom of the receiving cavity is inclined downward along the discharge direction. A feed inlet is opened at the top of one end of the screen box, and a discharge outlet 11 is opened at the bottom of the other end. The screening units are driven by a vibrating motor, and there are two or more of them.

[0039] The multi-stage vibrating screen 10 can be a product already available on the market, without limitations on its specific specifications, models, or operating parameters. Users can set it themselves according to their actual needs to achieve the desired performance. Generally speaking, the more screening units there are, the higher the particle size distribution accuracy of the screened material. However, too many screening units will lead to a more complex equipment structure, a higher failure rate, and higher maintenance costs.

[0040] Multiple screening units are arranged vertically and horizontally within the receiving cavity. The screening units are inclined downward along the discharge direction and located above the corresponding discharge port 11. The diameter of the screen holes of the multiple screening units decreases from top to bottom.

[0041] The main body of the screen box can be made of Q235 steel plate with a thickness of 6-10mm, and the interior is lined with wear-resistant steel plate or rubber lining to improve durability. The bottom of the receiving cavity is inclined at 5-15 degrees along the discharge direction to facilitate the flow of powder materials by gravity. Existing material guide plates or material distributors can be installed at the feed inlet to ensure that the material is evenly distributed along the width of the screening unit. Multiple discharge ports 11 are set according to the number of screening units; for example, three discharge ports 11 correspond to coarse aggregate, fine aggregate, and powder materials, respectively. Rubber curtains or sealing covers can be installed at the discharge ports 11 to prevent dust from escaping. Rubber curtains or sealing covers are existing technologies, and their specific structures and usage will not be described in detail.

[0042] Please see Figure 1 and Figure 2In some possible embodiments, the concrete crushing and screening device further includes a feeding elevator 40, which is used to convey materials to the feed end of the multi-stage vibrating screen 10. The feeding elevator 40 includes a feeding conveying mechanism 42 arranged vertically or obliquely upward, and a feeding hopper 41 located at the bottom feed end of the feeding conveying mechanism 42. The feeding hopper 41 can store a certain amount of material, and the feeding conveying mechanism 42 lifts the material from the feeding hopper 41 to the feed inlet of the multi-stage vibrating screen 10. Waste concrete material is filled into the feeding hopper 41 using equipment such as a loader.

[0043] The feeding elevator 40 is used to achieve continuous and stable material supply. By adjusting the feeding rate, it optimizes the load on the vibrating screen and crusher, improves system efficiency and stability, and reduces the risk of material blockage. The feeding conveyor 42 can be a bucket elevator, belt conveyor, or screw conveyor from the prior art.

[0044] Please see Figure 5 and Figure 6 In some possible embodiments, the lower surface of the primary crusher 20 used to form the discharge channel 211 is an arc-shaped surface. The discharge control mechanism 25 includes a discharge valve plate 251 and a discharge drive component 252. The discharge valve plate 251 is an arc-shaped plate-like component that rotates with the lower surface of the primary crusher 20. During rotation, the discharge valve plate 251 can control the opening and closing of the discharge channel 211. Specifically, the discharge valve plate 251 has a closed state that simultaneously covers the outlets of two discharge channels 211, and an open state that rotates to cover only one outlet of the discharge channel 211. The discharge drive component 252 is located in the primary crusher 20 and is used to drive the discharge valve plate 251 to switch between the closed and open states.

[0045] The discharge control mechanism 25 allows the primary crusher 20 to selectively discharge materials according to the demand for raw materials. When there is a greater demand for coarse aggregate, the larger coarse aggregate can be directly discharged through the corresponding discharge channel 211. When there is a greater demand for fine aggregate, the material can be further fed into the secondary crusher 30 through the corresponding discharge channel 211 for crushing into smaller particles, producing fine aggregate with smaller particle sizes.

[0046] The discharge drive component 252 can be a motor, a hydraulic telescopic rod, or other drive components, as long as it can drive the discharge valve plate 251 to rotate within a certain angle. In actual use, the rotation angle of the discharge valve plate 251 can be monitored in real time through limit switches, distance sensors, etc.

[0047] Please see Figure 3 , Figure 4 and Figure 7In some possible embodiments, considering that the feed end of the secondary crusher 30 is connected to the discharge port 11 of both the primary crusher 20 and the multi-stage vibrating screen 10, there may be a risk of material blockage during actual use. To reduce the probability of material blockage, the secondary crusher 30 is relatively long and has two working areas arranged along its long axis. The first working area is located below the discharge port 11 for discharging fine aggregate and is used to crush the fine aggregate obtained from the multi-stage vibrating screen 10 to a suitable particle size to obtain fine aggregate that meets the requirements. The concrete crushing and screening device also includes a horizontal feeder 50, which is located between the primary crusher 20 and the secondary crusher 30. It is used to transport the material discharged from the corresponding discharge channel 211 to the second working area of ​​the secondary crusher 30. The second working area is used to perform secondary crushing on the material discharged from the primary crusher 20. The two working areas work simultaneously without affecting each other, which can effectively avoid excessive material accumulation and material blockage. The secondary crusher 30 can be a double-roll crusher. The rollers of the double-roll crusher extend along the axial direction of the secondary crusher 30, and the two rollers are driven to rotate by a single drive device (such as a motor).

[0048] Please see Figure 7 In some possible embodiments, the horizontal feeder 50 is a screw conveyor arranged parallel to the long axis of the secondary crusher 30. The feed end of the screw conveyor is located below the corresponding discharge channel 211, and the bottom of the other end is provided with a first guide pipe 51 that communicates with the top of the secondary crusher 30.

[0049] Please see Figure 3 , Figure 4 and Figure 7 In some possible embodiments, the secondary crusher 30 is positioned below the primary crusher 20 in the height direction. Considering the significant height difference between the secondary crusher 30 and the multi-stage vibrating screen 10, a second guide pipe 31 is provided between the top of the secondary crusher 30 and the corresponding discharge port 11 of the multi-stage vibrating screen 10 to prevent the material from falling directly and causing a large impact. The second guide pipe 31 is a tortuous pipe in the height direction, which can buffer the falling speed of the material and reduce the impact. The second guide pipe 31 is made of steel plate or wear-resistant polyethylene material, has multiple bends, and is smooth inside, which can both buffer the falling speed of the material and prevent blockage.

[0050] The tortuous design of the second feed pipe 31 reduces the direct impact of materials on the secondary crusher 30, extends the equipment life, and also prevents the materials from being crushed due to excessive impact force during the falling process.

[0051] Please see Figure 8In some possible embodiments, the primary crusher 20 includes a housing 21, a crushing roller 22, an impact block 23, and a lifting mechanism 24. The housing 21 has a crushing chamber, the top of which is connected to a corresponding discharge port 11, and two discharge channels 211 are opened at the bottom of the crushing chamber. The crushing roller 22 is driven by a motor and is rotatably disposed in the crushing chamber along a horizontal axis. Crushing channels are formed between the crushing roller 22 and the two side walls of the crushing chamber. The impact block 23 is disposed in the crushing chamber and located above the crushing roller 22. The lifting mechanism 24 is disposed in the housing 21 and is used to drive the impact block 23 to move up and down.

[0052] During operation, the crushing roller 22 rotates at a constant speed, and the lifting mechanism 24 drives the impact block 23 to move up and down reciprocally. The material falls onto the crushing roller 22 and is crushed under the squeezing action of the crushing roller 22 and the impact action of the impact block 23. The crushed material falls into the discharge channel 211 below through the crushing channel. The lifting mechanism 24 can be a hydraulic cylinder, an electric telescopic rod, or other mechanical mechanism, and the impact frequency and force can be controlled as needed.

[0053] Please see Figure 9 and Figure 10 The impact block 23 includes an impact portion 231 and a connecting portion 232. The impact portion 231 is located inside the crushing chamber and above the crushing roller 22. The connecting portion 232 is connected to the top of the impact portion 231 and slides in cooperation with the outer casing 21. The lifting mechanism 24 includes a lifting wheel 241 and a lifting drive component. The lifting wheel 241 is located on one side of the connecting portion 232 and rotates in cooperation with the outer casing 21. During the rotation of the lifting wheel 241, it has a connected state in contact with the connecting portion 232 and a separated state. The lifting drive component is used to drive the lifting wheel 241 to rotate around its own axis. When in the connected state, the lifting wheel 241 can drive the impact block 23 to move upward. When the lifting wheel 241 rotates to the separated state, the impact block 23 disengages from the lifting wheel 241 and falls under the action of gravity, impacting the material and assisting in the crushing of the material.

[0054] like Figure 9 As shown, the lifting wheel 241 can be a rubber wheel, which is eccentrically rotated. During eccentric rotation, the outer surface of the rubber wheel can contact and be further compressed with the connecting part 232. Under the friction of the rubber wheel, the connecting part 232 is lifted upward. The rubber wheel continues to rotate, and when it rotates to the point where it no longer contacts the connecting part 232, the connecting part 232 and the impact part 231 fall together under the action of gravity. To improve the stability under force, multiple lifting wheels 241 can be provided on both sides of the connecting part 232.

[0055] like Figure 10As shown, the lifting wheel 241 can be a gear with an arc-shaped gear ring, and the connecting part 232 has a rack that meshes with the gear ring. When the gear ring and the rack mesh, the lifting wheel 241 can drive the connecting part 232 to rise. When the gear rotates to the point where the gear ring and the rack separate, the connecting part 232 and the impact part 231 fall together under the action of gravity.

[0056] Secondly, embodiments of this application also provide a recycled asphalt concrete production process, which uses the concrete crushing and screening device in any of the above embodiments to crush concrete materials, and uses the crushed aggregate as raw material to produce recycled asphalt concrete. The specific operating steps of the recycled asphalt concrete production process are prior art.

[0057] In one specific embodiment, the recycled asphalt concrete production process includes the following steps: S1: Feeding and pre-screening: The recycled concrete material is conveyed to the multi-stage vibrating screen 10 through the feeding elevator 40, and the material is screened into coarse aggregate, fine aggregate and powder material by the multi-stage vibrating screen 10.

[0058] S2: Staged crushing: a) The coarse aggregate is fed into the primary crusher 20 for primary crushing; during the operation of the primary crusher 20, the flow direction of the material after being crushed by the primary crusher 20 is controlled by operating the discharge control mechanism 25, so that part of it is directly discharged as finished coarse aggregate, and part of it enters the secondary crusher 30 for further crushing; b) Part or all of the coarse aggregate and fine aggregate after primary crushing are respectively fed into different working areas of the secondary crusher 30 for secondary crushing.

[0059] S3: Finished aggregate acquisition: Collect the powder material discharged from the multi-stage vibrating screen 10, the coarse aggregate directly discharged from the primary crusher 20, and the fine aggregate discharged from the secondary crusher 30 as raw materials for the production of recycled asphalt concrete.

[0060] S4: Aggregate pretreatment: The obtained recycled aggregate is washed and / or dried to remove attached impurities and control the moisture content.

[0061] S5: Recycled asphalt concrete mixing: The obtained recycled aggregate is mixed with new aggregate, asphalt binder and recycling agent in a predetermined proportion according to existing technology to prepare recycled asphalt concrete mixture.

[0062] It is understood that the parts in the above embodiments can be freely combined or deleted to form different combined embodiments. The specific contents of each combined embodiment will not be repeated here. After this description, it can be considered that the present invention specification has recorded each combined embodiment and can support different combined embodiments.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A concrete crushing and screening device, characterized in that, include: A multi-stage vibrating screen (10) is used to screen materials into at least three types according to particle size. The multi-stage vibrating screen (10) has at least three discharge ports (11) for discharging coarse aggregate, fine aggregate and powder material respectively. At least one primary crusher (20) has a feed end at the top, which is connected to the discharge port (11) for discharging coarse aggregate. The bottom of the primary crusher (20) is the discharge end, and it is provided with two discharge channels (211) and a discharge control mechanism (25) for controlling the opening or closing of the two discharge channels (211). At least one secondary crusher (30) has a feed end at the top and is connected to the discharge port (11) for discharging fine aggregate and one of the discharge channels (211), with the discharge end at the bottom of the secondary crusher (30).

2. The concrete crushing and screening device according to claim 1, characterized in that, The multi-stage vibrating screen (10) includes: A screen box, horizontally arranged, has an internal cavity with its bottom inclined downwards along the discharge direction. An inlet is located at the top of one end of the screen box, and an outlet (11) is located at the bottom of the other end. At least two screening units are arranged vertically and vertically within the receiving cavity. The screening units are arranged inclined downward along the discharge direction and located above the corresponding discharge port (11). The diameter of the screen holes of the multiple screening units decreases from top to bottom.

3. The concrete crushing and screening device according to claim 1, characterized in that, The concrete crushing and screening device also includes a feeding elevator (40), which is used to convey materials to the feed end of the multi-stage vibrating screen (10).

4. The concrete crushing and screening device according to claim 1, characterized in that, The primary crusher (20) forms an arc-shaped lower surface for the discharge channel (211), and the discharge control mechanism (25) includes: The discharge valve plate (251) is arc-shaped and rotatably engages with the lower surface of the primary crusher (20). The discharge valve plate (251) has a closed state that simultaneously covers the outlets of both discharge channels (211), and an open state that rotates to cover only one of the outlets of the discharge channel (211). The discharge drive unit (252) is located in the primary crusher (20) and is used to drive the discharge valve plate (251) to switch between the closed state and the open state.

5. The concrete crushing and screening device according to claim 1, characterized in that, The secondary crusher (30) has two working areas arranged along its own long axis, one of which is located below the discharge port (11) for discharging fine aggregate; The concrete crushing and screening device also includes a horizontal feeder (50), which is located between the primary crusher (20) and the secondary crusher (30) and is used to transport the material discharged from the corresponding discharge channel (211) to another working area of ​​the secondary crusher (30).

6. The concrete crushing and screening device according to claim 5, characterized in that, The horizontal feeder (50) is a screw conveyor arranged parallel to the long axis of the secondary crusher (30). The feed end of the screw conveyor is located below the corresponding discharge channel (211), and the bottom of the other end is provided with a first guide pipe (51) that communicates with the top of the secondary crusher (30).

7. The concrete crushing and screening device according to claim 1, characterized in that, The secondary crusher (30) is located below the primary crusher (20) in the height direction. A second guide pipe (31) is provided between the top of the secondary crusher (30) and the discharge port (11) corresponding to the multi-stage vibrating screen (10). The second guide pipe (31) is a tortuous pipe.

8. The concrete crushing and screening device according to claim 1, characterized in that, The primary crusher (20) includes: The outer shell (21) has a crushing chamber, the top of which is connected to the corresponding discharge port (11), and the bottom of which has two discharge channels (211). A crushing roller (22) is rotatably disposed in the crushing chamber in the horizontal direction, and crushing channels are formed between the crushing roller (22) and the two side walls of the crushing chamber respectively; An impact block (23) is disposed within the crushing chamber and positioned above the crushing roller (22); and A lifting mechanism (24) is provided on the outer shell (21) for driving the impact block (23) to move up and down.

9. The concrete crushing and screening device according to claim 8, characterized in that, The impact block (23) includes an impact part (231) and a connecting part (232). The impact part (231) is located in the crushing chamber and above the crushing roller (22). The connecting part (232) is connected to the top of the impact part (231) and slides with the outer shell (21). The lifting mechanism (24) includes: A lifting wheel (241) is disposed on one side of the connecting portion (232) and rotatably engages with the outer casing (21). During the rotation of the lifting wheel (241), the lifting wheel (241) has a connected state in contact with the connecting portion (232) and a separated state disengaged from the connecting portion (232); and A lifting drive is used to drive the lifting wheel (241) to rotate around its own axis.

10. A process for producing recycled asphalt concrete, characterized in that, The concrete crushing and screening device according to any one of claims 1 to 9 is used to crush concrete materials.

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