Gravel centrifugal separation and circulating mixing device and method

Abstract

The invention relates to the field of building material recycling, and discloses a gravel centrifugal separation and circulating mixing device which comprises a vibration screening machine, a material conveying device, a material conveying device and a material mixing device, and the vibration screening machine is used for vibration screening of fluid concrete; the frame body is used for supporting the vibration screening machine; the storage tank is positioned below the vibration screening machine; the first conveying pipe is used for conveying the fluid concrete into the vibration screening machine; a sand settling opening of the cyclone is located at the feeding end of the vibration screening machine; one end of the second conveying pipe is communicated with the discharging port of the storage tank, and the other end of the second conveying pipe is communicated with the feeding port of the cyclone; the conveying pipe III is communicated with an overflow port of the cyclone and is used for conveying out the slurry; and the material mixing and stirring mechanism is used for receiving the gravel vibrated and screened out by the vibration screening machine and receiving and stirring the slurry conveyed out by the cyclone. According to the device, the sand and the slurry in the over-filling material are effectively separated and recycled, the sand and the slurry are accurately mixed, the recycling of the over-filling material is ensured, the cost waste and the emission of waste and pollutants on a construction site are reduced, and the environmental influence is reduced.

Description

Technical Field

[0001] The present application relates to the field of building material recycling, and in particular to a device and method for centrifugal separation and circulation mixing of sand and gravel. Background Art

[0002] In bored pile construction, overfilled materials often occur. Overfilled materials refer to the excess materials that exceed the design elevation due to excessive concrete pouring or improper concrete fluidity control. Overfilled materials usually need to be recycled and processed to reduce cost waste, construction waste, and environmental pollution.

[0003] However, in the process of implementing relevant technical solutions, it was found that at least the following technical problems exist: At present, for the recovery and treatment of over-filled materials, traditional treatment methods such as mechanical separation only carry out preliminary separation of materials. The separated sand and slurry are relatively rough and cannot be recycled. Summary of the invention

[0004] The present application provides a centrifugal sand and gravel separation and circulating mixing device and method, which solves the technical problem that the separated sand and gravel and slurry in the prior art are relatively coarse and cannot be recycled. The application realizes effective separation and recovery of sand and gravel and slurry in over-filled materials, and accurately mixes sand and gravel and slurry, thereby ensuring the recycling of over-filled materials, reducing cost waste, reducing waste and pollutant emissions at the construction site, and reducing environmental impact.

[0005] The present application provides a sand and gravel centrifugal material distribution and circulating mixing device, comprising: a vibrating screen machine, which is used to vibrate and screen fluid concrete; a frame, which is used to support the vibrating screen machine; a storage tank, which is installed on the frame and located below the vibrating screen machine; a conveying pipe 1, on which a slurry pump 1 is installed, and the slurry pump 1 is used to convey fluid concrete to the vibrating screen machine through the conveying pipe 1; a cyclone, which is located above the vibrating screen machine, and the sand settling port of the cyclone is located at the feed end of the vibrating screen machine; a conveying pipe 2, one end of which is connected with the discharge port of the storage tank, and the other end is connected with the feed port of the cyclone, and the conveying pipe 2 is provided with a slurry pump 2 for conveying the slurry in the storage tank to the cyclone through the conveying pipe 2; a conveying pipe 3, which is connected with the overflow port of the cyclone and is used to convey out the slurry; a mixing and stirring mechanism, which is used to receive the sand and gravel vibrated and screened by the vibrating screen machine and the slurry conveyed by the cyclone, and stir them.

[0006] Furthermore, the vibrating screen machine: a frame plate, located above the frame body; a vibration spring, fixed between the frame plate and the frame body; a fine screen upper layer vibrating screen, located above the material storage trough and fixed on the frame plate; a coarse screen lower layer vibrating screen, located below the fine screen upper layer vibrating screen and fixed on the frame plate; a vibration motor, fixedly mounted on the frame plate.

[0007] Furthermore, the sand settling port of the cyclone is located at the feed end of the upper layer of the fine screen in the vibrating screen machine, and the discharge end of the conveying pipe 1 is located at the feed end of the lower layer of the coarse screen.

[0008] Furthermore, an electric gate valve 1 is installed on the conveying pipe 3, and a reflux pipe is connected to the conveying pipe 3. The reflux pipe is located between the electric gate valve 1 and the overflow port of the cyclone. An electric gate valve 2 is installed on the reflux pipe, and the discharge port of the reflux pipe is located at the feed end of the upper layer of the fine screen.

[0009] Furthermore, the mixing and stirring mechanism includes: a mixing tank, located on one side of the vibrating screen; a conveying pipe four, one end of which is connected to the slurry feed port of the mixing tank, and the other end is connected to the conveying pipe three, and a flow valve is installed on the conveying pipe four; a metering hopper, installed at the sand and gravel feed port of the mixing tank; a screw conveyor, one end of which is located below the discharge port of the upper layer of the fine screen in the vibrating screen, and the other end is located above the feed port of the metering hopper.

[0010] Furthermore, the delivery pipe three is connected to a flushing pipe, an electric gate valve three is installed on the flushing pipe, the water outlet of the flushing pipe is located in the storage tank, and the slurry suction port of the delivery pipe two and the water outlet of the flushing pipe are respectively located at both ends of the storage tank.

[0011] Furthermore, the flushing pipe portion located in the material storage tank is connected to a plurality of flushing nozzles, and the plurality of flushing nozzles are evenly distributed along the length direction of the flushing pipe.

[0012] The present application also provides a method for centrifugal classification and circulating mixing of sand and gravel, which adopts the above-mentioned centrifugal classification and circulating mixing device of sand and gravel, and the method for centrifugal classification and circulating mixing of sand and gravel includes: conveying fluid concrete to the lower layer of the coarse screen through a conveying pipe 1, and the fluid concrete is coarsely screened to form a slurry with small particles of sand and gravel; conveying the slurry with small particles of sand and gravel in the storage tank to the cyclone by using a conveying pipe 2, and the small particles of sand and gravel in the slurry enter the upper layer of the fine screen, and the slurry enters the conveying pipe 3; conveying the slurry to a mixing tank by using a conveying pipe 4; conveying the sand and gravel to a metering hopper by using a bolt conveyor; the flow valves on the metering hopper and the conveying pipe 3 respectively control the amount of sand and gravel and the amount of slurry entering the mixing tank; the mixing tank stirs the sand and gravel and the slurry to form fluid concrete.

[0013] Furthermore, the electric gate valve one is closed, the electric gate valve three is opened, the mortar in the delivery pipe three enters the flushing pipe, and the slurry in the flushing pipe flushes the storage tank.

[0014] One or more technical solutions provided in this application have at least the following technical effects or advantages:

[0015] By using a vibrating screen to separate the debris and usable sand and gravel in the over-filled materials, and using a cyclone to separate the sand and gravel from the slurry, and then accurately controlling the amount of sand and gravel and slurry entering the mixing tank, high-quality fluid concrete with precisely controlled proportions is finally formed under the stirring of the mixing tank, which effectively separates and recovers the sand and gravel and slurry in the over-filled materials, and then reuses them to form fluid concrete, reducing cost waste, waste and pollutant emissions at the construction site, and reducing environmental impact. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is an overall schematic diagram of a sand and gravel centrifugal material distribution and circulating mixing device in an embodiment of the present application;

[0017] Figure 2 for Figure 1 Another perspective view of the medium sand and gravel centrifugal distribution and circulating mixing device;

[0018] Figure 3 for Figure 2 Schematic diagram of the structure of the medium vibration screening machine;

[0019] Figure 4 for Figure 1 The cross-sectional diagram of the middle part mainly illustrates the structure of the flushing pipe in the storage tank;

[0020] Figure 5 for Figure 1 Another view of the medium sand and gravel centrifugal distribution and circulating mixing device;

[0021] Figure 6This is a schematic flow chart of a method for centrifugal separation and circulating mixing of sand and gravel in an embodiment of the present application;

[0022] In the figure: 1. vibrating screen; 11. frame plate; 12. vibration spring; 13. vibrating screen mesh on the upper layer of fine screen; 14. vibrating screen mesh on the lower layer of coarse screen; 15. vibration motor; 2. frame; 3. storage tank; 4. conveying pipe 1; 41. slurry pump 1; 5. cyclone; 6. conveying pipe 2; 61. slurry pump 2; 7. conveying pipe 3; 71. electric gate valve 1; 8. mixing and stirring mechanism; 81. stirring tank; 82. conveying pipe 4; 821. flow valve; 83. metering hopper; 84. screw conveyor; 91. reflux pipe; 911. electric gate valve 2; 92. flushing pipe; 921. electric gate valve 3; 922. flushing nozzle. DETAILED DESCRIPTION

[0023] The embodiment of the present application discloses a device and method for centrifugal separation and circulating mixing of sand and gravel, wherein fluid concrete is conveyed to a coarse screen lower layer vibrating screen 14 through a conveying pipe 14, the fluid concrete is coarsely screened to form a slurry with small particles of sand and gravel, and then the slurry with small particles of sand and gravel in a storage tank 3 is conveyed to a cyclone 5 through a conveying pipe 26, the small particles of sand and gravel in the slurry enter the fine screen upper layer vibrating screen 13, and the slurry enters a conveying pipe 3 7, and then the slurry is conveyed to a mixing tank 81 through a conveying pipe 4 82, and the sand and gravel are conveyed to a metering hopper 83 by a bolt conveyor, the metering hopper 83 and the flow valve 821 on the conveying pipe 3 7 respectively control the amount of sand and gravel and the amount of slurry entering the mixing tank 81, and the mixing tank 81 mixes the sand and gravel and the slurry to form fluid concrete, thereby achieving effective separation and recovery of sand and gravel and slurry in overfilled materials, and accurately mixing sand and gravel with the slurry, thereby ensuring the recycling of overfilled materials and reducing cost waste.

[0024] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0025] The present application provides a sand and gravel centrifugal material distribution and circulation mixing device, referring to Figure 1 and Figure 2The sand and gravel centrifugal material distribution and circulating mixing device includes a vibrating screen machine 1, a frame 2, a storage tank 3, a conveying pipe 1 4, a cyclone 5, a conveying pipe 2 6, a conveying pipe 3 7, a mixing and stirring mechanism 8, a reflux pipe 91 and a flushing pipe 92. The frame 2 is placed on the ground, the storage tank 3 is installed in the frame 2, the storage tank 3 is in a rectangular shape and is arranged horizontally, and the top surface of the storage tank 3 is completely open. The vibrating screen machine 1 is installed on the frame 2, and the vibrating screen machine 1 is located directly above the storage tank 3, and the material flowing out of the vibrating screen machine 1 will enter the storage tank 3. The cyclone 5 is inclined and located at the feed end of the vibrating screen machine 1, and the height of the overflow port in the cyclone 5 is higher than the height of the sand settling port. The mixing and stirring mechanism 8 is located on one side of the vibrating screen machine 1, and the mixing and stirring mechanism 8 is arranged in parallel with the vibrating screen machine 1.

[0026] Continue to refer to Figure 1 and Figure 3 As shown, the vibrating screen machine 1 includes a frame plate 11, a vibration spring 12, a fine screen upper layer vibration screen mesh 13, a coarse screen lower layer vibration screen mesh 14 and a vibration motor 15. A plurality of frame plates 11 are provided, and the frame plates 11 are located above the frame body 2, and there is a gap between the bottom of the frame plate 11 and the top of the frame body 2, and the plurality of frame plates 11 are evenly distributed along the length direction of the material storage trough 3. The vibration spring 12 is fixed between the bottom of the frame plate 11 and the top of the frame body 2, and a plurality of vibration springs 12 are provided on both sides of the top surface of the frame body 2. The fine screen upper layer vibration screen 13 is located above the storage tank 3 and fixed on the frame plate 11. One end of the fine screen upper layer vibration screen 13 close to the cyclone 5 is higher than the other end; the coarse screen lower layer vibration screen 14 is located below the fine screen upper layer vibration screen 13 and fixed on the frame plate 11. The coarse screen lower layer vibration screen 14 and the fine screen upper layer vibration screen 13 are parallel to each other, and the mesh of the coarse screen lower layer vibration screen 14 is larger than the fine screen upper layer vibration screen 13. The coarse screen lower layer vibration screen 14 can screen out sand and debris with larger particles, and the fine screen upper layer vibration screen 13 can screen out sand and gravel with smaller particles. The slurry can fall from the fine screen upper layer vibration screen 13 and the coarse screen lower layer vibration screen 14 and enter the storage tank 3. The vibration motor 15 is fixedly installed on the frame plate 11. Starting the vibration motor 15 can make the vibration screen machine 1 start to operate.

[0027] Reference Figure 1 and Figure 2As shown, a slurry pump 41 is installed on the delivery pipe 4, and the discharge end of the delivery pipe 4 is located at the feed end of the coarse screen lower layer vibration screen 14. The feed end of the delivery pipe 4 can be placed in a pool filled with fluid concrete to be divided. The slurry pump 41 can be used to transport the fluid concrete in the pool through the delivery pipe 4 to the coarse screen lower layer vibration screen 14 of the vibration screen machine 1. After the fluid concrete enters the coarse screen lower layer vibration screen 14, the larger sand and gravel particles will be screened out, and the remaining slurry with small sand and gravel particles will fall into the storage tank 3. In addition, the sand settling port of the cyclone 5 is located at the feed end of the fine screen upper layer vibration screen 13 in the vibration screen machine 1, and the slurry with sand and gravel flowing out of the cyclone 5 will enter the fine screen upper layer vibration screen 13 for screening.

[0028] Continue to refer to Figure 1 and Figure 2 As shown, a slurry pump 2 61 is installed on the delivery pipe 2 6, one end of the delivery pipe 2 6 is connected to the discharge port of the storage tank 3, and the other end is connected to the feed port of the cyclone 5. The slurry in the storage tank 3 can be delivered to the cyclone 5 through the delivery pipe 2 6 by the slurry pump 2 61. The slurry that falls into the storage tank 3 from the lower layer of the coarse screen 14 can enter the cyclone 5 under the action of the slurry pump 2 61. Under the centrifugal force of the cyclone 5, the small particles of sand and gravel in the slurry and part of the slurry can flow out from the sand settling port of the cyclone 5, and finally flow into the upper layer of the fine screen 13, and most of the slurry will flow out from the overflow port of the cyclone 5.

[0029] Reference Figure 2 and Figure 4 As shown, the delivery pipe 3 7 is connected to the overflow port of the cyclone 5, and an electric gate valve 1 71 is installed on the delivery pipe 3 7. The electric gate valve 1 71 can be controlled by remote control or program setting to achieve the separation and unblocking of the delivery pipe 3 7. One end of the return pipe 91 is connected to the delivery pipe 3 7, and the other end is located at the feed end of the fine screen upper layer vibration screen 13. The electric gate valve 2 911 is installed on the return pipe 91, and the electric gate valve 2 911 can be controlled by remote control or program setting to achieve the separation and unblocking of the return pipe 91, and the return pipe 91 is located between the electric gate valve 1 71 and the overflow port of the cyclone 5. Therefore, when the electric gate valve 1 71 is closed and the electric gate valve 2 911 is opened, the slurry in the cyclone 5 will flow to the return pipe 91 through the delivery pipe 3, and then flow from the return pipe 91 to the fine screen upper layer vibration screen 13, so as to achieve the secondary vibration screening of the slurry in the cyclone 5. When the slurry flowing out of the cyclone 5 is suitable for secondary utilization, the electric gate valve 2 911 is closed and the electric gate valve 1 71 is opened, so that the slurry in the conveying pipe 3 7 can be reused.

[0030] Continue to refer to Figure 2 and Figure 4As shown, the flushing pipe 92 is connected to the delivery pipe 3 7, the water outlet of the flushing pipe 92 is located in the storage tank 3, and the pipe part of the flushing pipe 92 located in the storage tank 3 is connected with a plurality of flushing nozzles 922, and the plurality of flushing nozzles 922 are evenly distributed along the length direction of the flushing pipe 92. The flushing pipe 92 is installed with an electric gate valve 3 921, which can be controlled by remote control or program setting to achieve the isolation and unblocking of the flushing pipe 92, and the electric gate valve 1 71 is located between the flushing pipe 92 and the overflow port of the cyclone 5. When the electric gate valve 1 71 and the electric gate valve 3 921 are opened at the same time, the slurry in the delivery pipe 3 will enter the flushing pipe 92, and the slurry in the flushing pipe 92 will be sprayed out by the flushing nozzle 922, so that the inner wall of the storage tank 3 can be flushed, and the electric gate valve 3 921 can be closed to stop the flushing.

[0031] Reference Figure 5 As shown, the mixing and stirring mechanism 8 includes a mixing tank 81, a conveying pipe 82, a metering hopper 83, and a screw conveyor 84. The mixing tank 81 is located on one side of the vibrating screen 1 and is close to the cyclone 5; one end of the conveying pipe 82 is connected to the slurry feed port of the mixing tank 81, and the other end is connected to the conveying pipe 3 7. The height of the slurry feed port of the mixing tank 81 is lower than the height of the connection between the conveying pipe 3 7 and the conveying pipe 4 82 to ensure that the slurry in the conveying pipe 3 7 can flow into the mixing tank 81. A flow valve 821 is installed on the conveying pipe 4 82 to control the amount of slurry entering the mixing tank 81; the metering hopper 83 is installed at the sand and gravel feed port of the mixing tank 81. At the opening of the vibrating screen 1, the metering hopper 83 can measure the weight and flow the material into the mixing tank 81 at the rated weight; the screw conveyor 84 is located on one side of the vibrating screen 1 and on the same side as the mixing tank 81. One end of the screw conveyor 84 is located below the discharge port of the fine screen upper layer vibrating screen 13 in the vibrating screen 1, and the other end is located above the feed port of the metering hopper 83. The small particles of sand and gravel screened by the fine screen upper layer vibrating screen 13 will fall into the screw conveyor 84, and the screw conveyor 84 can be used to transport the small particles of sand and gravel to the metering hopper 83. Therefore, the flow valve 821 on the metering hopper 83 and the conveying pipe 37 can respectively control the amount of sand and gravel and the amount of slurry entering the mixing tank 81, so that the proportion can be adjusted in real time, and the proportion and performance of the mixed materials can be accurately controlled, ensuring the quality of the recycled concrete and avoiding the problem of quality degradation.

[0032] The functional principle of the sand and gravel centrifugal distribution and circulating mixing device can be explained through the following operation methods:

[0033] When it is necessary to recycle and process the overfilled materials generated during bored pile construction, the fluid concrete to be divided is placed in a pool, and is conveyed to the coarse screen lower layer vibrating screen 14 through the conveying pipe 1 4. The slurry falls into the storage tank 3, and is conveyed to the cyclone 5 through the conveying pipe 2 6. Under the centrifugal force of the cyclone 5, the small particles of sand and gravel in the slurry and part of the slurry can flow out from the sand settling port of the cyclone 5, and most of the slurry can flow out from the overflow port of the cyclone 5. The metering hopper 83 and the flow valve 821 on the conveying pipe 3 7 can respectively control the amount of sand and gravel and the amount of slurry entering the mixing tank 81. The mixing tank 81 is stirred to finally form high-quality fluid concrete with a precisely controlled ratio.

[0034] The present application also provides a method for centrifugal separation and circulating mixing of sand and gravel, referring to Figure 6 As shown, the method for centrifugal separation and circulating mixing of sand and gravel includes:

[0035] S1, coarse screen for fluid concrete.

[0036] In the specific implementation, a slurry pump 41 can be used to transport the fluid concrete to be separated in the pool through a conveying pipe 4 to the coarse screen lower layer vibrating screen 14 of the vibrating screen machine 1. After the fluid concrete enters the coarse screen lower layer vibrating screen 14, larger particles of sand and gravel and debris will be screened out, and the remaining slurry with small particles of sand and gravel will fall into the storage tank 3.

[0037] S2, cyclone separates sand and slurry.

[0038] In a specific implementation, the slurry in the storage tank 3 can enter the cyclone 5 under the action of the slurry pump 2 61. Under the action of the centrifugal force of the cyclone 5, the small particles of sand and gravel in the slurry and part of the slurry can flow out from the sand settling port of the cyclone 5 and finally flow into the upper layer of the fine screen 13, while most of the slurry will flow out from the overflow port of the cyclone 5.

[0039] S3, accurately controls the slurry entering the mixing tank.

[0040] In a specific implementation, the slurry flowing out of the overflow port of the cyclone 5 can enter the delivery pipe 82, and the flow valve 821 on the delivery pipe 82 can accurately control the amount of slurry entering the mixing tank 81.

[0041] S4, accurately controls the sand and gravel entering the mixing tank.

[0042] In a specific implementation, the small particles of sand and gravel screened out by the fine screen upper layer vibrating screen 13 will fall into the screw conveyor 84, and the screw conveyor 84 can be used to transport the small particles of sand and gravel to the metering hopper 83, and the metering hopper 83 can measure the weight and flow the sand and gravel into the mixing tank 81 at a rated weight.

[0043] S5, stirring and mixing.

[0044] In specific implementation, after the rated amount of sand, gravel and slurry flows into the mixing tank 81, it can be mixed to eventually form high-quality fluid concrete with precisely controlled proportions, thereby achieving effective separation and recovery of sand, gravel and slurry in over-filled materials, and accurately mixing sand, gravel and slurry, thereby ensuring the recycling of over-filled materials, reducing cost waste, reducing waste and pollutant emissions at the construction site, and reducing environmental impact.

[0045] S6, flush the storage tank.

[0046] In a specific implementation, the electric gate valve 1 71 can be closed and the electric gate valve 3 921 can be opened, the mortar in the delivery pipe 3 7 will enter the flushing pipe 92, and the flushing nozzle 922 on the pipe part of the delivery pipe 3 7 located in the storage tank 3 will spray out the slurry, thereby flushing the inner wall of the storage tank 3. When the electric gate valve 3 921 is closed, the flushing can be stopped.

[0047] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

[0048] What has been described above is only a preferred specific implementation manner of the embodiments of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can make equivalent substitutions or changes according to the technical scheme and concept of the present application within the technical scope disclosed in the present application, which should be covered by the protection scope of the present application.

Claims

1. A sand and gravel centrifugal material distribution and circulating mixing device, characterized in that: include: A vibrating screen machine (1) for vibrating and screening fluid concrete; A frame (2) used for supporting the vibrating screen machine (1); A material storage trough (3) is installed on the frame (2) and is located below the vibrating screen machine (1); A delivery pipe (4), wherein a slurry pump (41) is installed on the delivery pipe (4), and the slurry pump (41) is used to deliver fluid concrete to the vibrating screen (1) through the delivery pipe (4); A cyclone (5) is located above the vibrating screen machine (1), and a sand settling port of the cyclone (5) is located at the feed end of the vibrating screen machine (1); A second conveying pipe (6), one end of which is in communication with the discharge port of the storage tank (3), and the other end of which is in communication with the feed port of the cyclone (5); a second slurry pump (61) is provided on the second conveying pipe (6) for conveying the slurry in the storage tank (3) to the cyclone (5) through the second conveying pipe (6); A delivery pipe (7) connected to the overflow port of the cyclone (5) for delivering the slurry; The mixing and stirring mechanism (8) is used to receive the sand and gravel screened out by the screen vibrating machine (1) and the slurry delivered by the cyclone (5), and to stir them.

2. A sand and gravel centrifugal material distribution and circulating mixing device as claimed in claim 1, characterized in that: The vibrating screen machine (1): A frame plate (11) located above the frame body (2); A vibration spring (12) is fixed between the frame plate (11) and the frame body (2); A fine screen upper layer vibrating screen (13) is located above the material storage tank (3) and fixed on the frame plate (11); A coarse screen lower layer vibrating screen (14) is located below the fine screen upper layer vibrating screen (13) and is fixed on the frame plate (11); The vibration motor (15) is fixedly mounted on the frame plate (11).

3. A sand and gravel centrifugal material distribution and circulating mixing device as claimed in claim 2, characterized in that: The sand settling port of the cyclone (5) is located at the feed end of the fine screen upper layer vibrating screen (13) in the vibrating screen machine (1), and the discharge end of the conveying pipe 1 (4) is located at the feed end of the coarse screen lower layer vibrating screen (14).

4. A sand and gravel centrifugal material distribution and circulating mixing device as claimed in claim 2, characterized in that: The conveying pipe three (7) is provided with an electric gate valve one (71), the conveying pipe three (7) is connected with a return pipe (91), the return pipe (91) is located between the electric gate valve one (71) and the overflow port of the cyclone (5), the return pipe (91) is provided with an electric gate valve two (911), and the discharge port of the return pipe (91) is located at the feed end of the upper layer vibration screen (13) of the fine screen.

5. A sand and gravel centrifugal material distribution and circulating mixing device as claimed in claim 2, characterized in that: The mixing and stirring mechanism (8) comprises: A stirring tank (81) is located on one side of the vibrating screen machine (1); A delivery pipe four (82), one end of which is connected to the slurry feed port of the stirring tank (81), and the other end of which is connected to the delivery pipe three (7), and a flow valve (821) is installed on the delivery pipe four (82); A metering hopper (83) is installed at the sand and gravel feeding port of the mixing tank (81); The screw conveyor (84) has one end located below the discharge port of the fine screen upper layer vibrating screen (13) in the vibrating screen machine (1), and the other end located above the feed port of the metering hopper (83).

6. A sand and gravel centrifugal material distribution and circulating mixing device as claimed in claim 1, characterized in that: The conveying pipe (3) (7) is connected to a flushing pipe (92), and an electric gate valve (3) (921) is installed on the flushing pipe (92). The water outlet of the flushing pipe (92) is located in the material storage tank (3), and the slurry suction port of the conveying pipe (2) (6) and the water outlet of the flushing pipe (92) are respectively located at two ends of the material storage tank (3).

7. A sand and gravel centrifugal material distribution and circulating mixing device as claimed in claim 6, characterized in that: The flushing pipe (92) is connected to a pipe portion located in the material storage tank (3) with a plurality of flushing nozzles (922), and the plurality of flushing nozzles (922) are evenly distributed along the length direction of the flushing pipe (92).

8. A method for centrifugal separation and circulating mixing of sand and gravel, characterized in that: A sand and gravel centrifugal material distribution and circulating material mixing device as claimed in any one of claims 1 to 7 is used, and a sand and gravel centrifugal material distribution and circulating material mixing method comprises: The fluid concrete is conveyed to the coarse screen lower layer vibration screen (14) through the conveying pipe 1 (4), and the fluid concrete is coarsely screened to form a slurry with small particles of sand and gravel; The slurry containing small sand and gravel particles in the storage tank (3) is transported to the cyclone (5) by using the second conveying pipe (6), the small sand and gravel particles in the slurry enter the upper vibrating screen (13) of the fine screen, and the slurry enters the third conveying pipe (7); The slurry is transported to the mixing tank (81) by using the transport pipe (82); The sand and gravel are conveyed to the measuring hopper (83) by means of a bolt conveyor (84); The flow valve (821) on the metering hopper (83) and the delivery pipe (7) respectively controls the amount of sand and gravel and the amount of slurry entering the mixing tank (81); The mixing tank (81) mixes the sand and the slurry to form a fluid concrete.

9. A method for centrifugal distribution and circulating mixing of sand and gravel as claimed in claim 8, characterized in that: Also includes: The electric gate valve 1 (71) is closed, the electric gate valve 3 (921) is opened, the mortar in the delivery pipe 3 (7) enters the flushing pipe (92), and the slurry in the flushing pipe (92) flushes the storage tank (3).

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