Gravel screening device for municipal construction

Abstract

The invention relates to the technical field of municipal construction equipment, and provides a gravel screening device for municipal construction, which comprises a machine body, the machine body is provided with a screening space, and the screening space is provided with a screening inlet; the fine screen drum part is arranged in the screening space and is provided with a first blanking cavity, and the first blanking cavity is provided with a first blanking outlet; the rotating screen part is rotationally arranged on the fine screen drum part, a plurality of first discharging holes are formed in the rotating screen part in the circumferential direction, the first discharging holes are communicated with the first discharging cavity, and the first discharging holes are located below the screening inlet. By means of the technical scheme, the problems that in the prior art, in municipal construction, an existing gravel screening technology needs large equipment, the occupied area is large, much dust is raised, and the requirements for efficient screening and environmental protection of gravel of various particle sizes in a limited construction space are difficult to meet are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of municipal construction equipment, and in particular to a sand and gravel screening device for municipal construction. Background Art

[0002] In the process of municipal construction, sand and gravel are indispensable and important building materials. In order to obtain sand and gravel of different particle sizes to meet the diverse construction needs, such as road construction, building construction, etc., it is necessary to accurately screen the sand and gravel. However, there are some significant problems with the existing sand and gravel screening technology. In the prior art, if you want to achieve effective screening of multiple particle sizes (such as large particle sizes greater than 20mm for laying road base and subbase, medium particle sizes between 5-20mm are important coarse aggregates in concrete preparation, small particle sizes between 2-5mm as fine aggregates in concrete, and fine sand less than 2mm for mixing mortar with high precision requirements), you often need to rely on large screening equipment. These large equipment are not only bulky, but also difficult to meet their needs for sufficient space at the construction site. This brings great difficulties to the planning and layout of the construction site, limiting the flexibility and efficiency of the construction. In addition, these large screening equipment usually generate a lot of dust during operation. A large amount of dust not only causes serious pollution to the environment of the construction site and affects the health of construction workers, but may also have adverse effects on the surrounding ecological environment and residents' lives. At the same time, dust will also cause certain obstacles to the operation and maintenance of equipment, increasing the risk of equipment failure. Summary of the invention

[0003] The present invention proposes a sand and gravel screening device for municipal construction, which solves the problem that the existing sand and gravel screening technology in municipal construction in the related technology requires large equipment, occupies a large area, and produces a lot of dust, and is difficult to meet the requirements of efficient screening of sand and gravel with various particle sizes and environmental protection in a limited construction space.

[0004] The technical solution of the present invention is as follows: A sand and gravel screening device for municipal construction, comprising: A machine body, wherein the machine body has a screening space, and the screening space has a screening inlet; A fine screen cylinder, wherein the fine screen cylinder is arranged in the screening space, and the fine screen cylinder has a first material dropping cavity, and the first material dropping cavity has a first material dropping outlet; A rotating screen member is rotatably arranged on the fine screen cylinder member, and the rotating screen member has a plurality of first drop holes in the circumference thereof, wherein the first drop holes lead to the first drop cavity, and the first drop holes are located below the screening inlet.

[0005] As a further technical solution, the rotating screen element has a first conical surface, and the first blanking hole is a strip hole along the radial direction of the first conical surface.

[0006] As a further technical solution, the screening space further has a second material outlet and a third material outlet, and further comprises: A separation screen element, wherein the separation screen element is arranged in the screening space, and the separation screen element has an inner shell portion and an outer shell portion, a second blanking space is formed between the inner shell portion and the fine screen cylinder, and a third blanking space is formed between the outer shell portion and the inner wall of the screening space, the second blanking space is connected with the outside through the second blanking outlet, and the third blanking space is connected with the outside through the third blanking outlet, and a top edge portion is provided at the top between the inner shell portion and the outer shell portion, and the top edge portion is located below the rotating screen element.

[0007] As a further technical solution, a first guiding inclined surface is provided between the top edge portion and the outer shell portion, and a second guiding inclined surface is provided between the top edge portion and the inner shell portion.

[0008] As a further technical solution, the first guide slope has a second blanking hole, the second guide slope has a third blanking hole, a fourth blanking space is formed between the outer shell part and the inner shell part, the second blanking hole and the second blanking hole both lead to the fourth blanking space, and the fourth blanking space has a fourth blanking outlet.

[0009] As a further technical solution, the first guiding inclined surface and the second guiding inclined surface are both conical surfaces, and the second blanking hole and the third blanking hole are both strip holes along the radial direction.

[0010] As a further technical solution, it also includes: A main shaft is rotatably arranged on the machine body and extends into the first blanking cavity. The rotating screen is arranged on the main shaft and rotates synchronously with the main shaft.

[0011] As a further technical solution, it also includes: A rotating top member, the rotating top member is arranged on the main shaft and is rotatably arranged on the fine screen cylinder member, the rotating top member has an outwardly extending shell portion, the length direction of the outwardly extending shell portion is along the radial direction of rotation of the rotating top member, the outwardly extending shell portion is located in the second blanking space, and the outwardly extending shell portion has an outwardly extending guide groove along the length direction; A top block, the top block being slidably disposed in the outwardly extending guide groove; a first elastic member, wherein one end of the first elastic member acts on the bottom wall of the outwardly extending guide groove, and the other end of the first elastic member acts on the top block to provide a force for the top block to move away from the bottom wall of the outwardly extending guide groove; Abutment blocks, wherein the abutment blocks are arranged in a circle on the inner wall of the inner shell part, and the abutment blocks have a rising guide section and a falling section. The rising guide sections and the falling sections of several abutment blocks are connected end to end in sequence, and the top block is configured to be driven by the rotating top member to rotate and then slide and abut with the rising guide section and the falling section in sequence, and after leaving the falling section, it impacts the rising guide section of the adjacent abutment block.

[0012] As a further technical solution, the top of the machine body has a third guiding slope, and the screening inlet is located at the bottom of the third guiding slope.

[0013] As a further technical solution, the first material outlet, the second material outlet, the third material outlet and the fourth material outlet are all arranged in pairs, facing the two sides of the machine body respectively.

[0014] The working principle and beneficial effects of the present invention are: In the present invention, sand and gravel for construction are poured in from the screening inlet. The rotating screen starts to rotate, and the sand and gravel fall on the rotating screen. Sand and gravel with a particle size smaller than the first drop hole enter the first drop cavity through the first drop hole, and are finally discharged from the first drop outlet. Sand and gravel with a larger particle size remain on the rotating screen and continue to move. This solution has a compact structure and occupies a small space, which is suitable for the limited space conditions of municipal construction sites. The rotating design of the rotating screen improves the screening efficiency and can quickly separate sand and gravel that meet the particle size requirements. It effectively realizes the preliminary particle size screening, laying the foundation for the subsequent further subdivision of sand and gravel with different particle sizes. It reduces the workload of manual screening and improves construction efficiency. It reduces the risk of construction progress delays due to untimely screening. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The preferred implementation modes will be described below in a clear and understandable manner with reference to the accompanying drawings to further illustrate the above-mentioned characteristics, technical features, advantages and implementation methods of the present invention.

[0016] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 It is another perspective structural schematic diagram of the present invention; Figure 3 It is a schematic diagram of the internal structure of the present invention; Figure 4 for Figure 3 A partial enlarged structural diagram of the middle part; Figure 5 for Figure 3 Schematic diagram of the partially enlarged structure of part B in the middle.

[0017] In the figure: body 1, screening space 101, screening inlet 102, second blanking outlet 103, third blanking outlet 104, third guide slope 105, fine screen cylinder 2, first blanking cavity 201, first blanking outlet 202, rotating screen 3, first blanking hole 301, first conical surface 302, separation screen 4, inner shell 401, outer shell 402, second blanking space 403, third blanking cavity 201, first blanking outlet 202, rotating screen 3, first blanking hole 301, first conical surface 302, separation screen 4, inner shell 401, outer shell 402, second blanking space 403, third blanking cavity 201, first blanking outlet 202, first blanking cavity 201, first blanking outlet 202, first blanking cavity 201, first blanking cavity ...3, first blanking cavity 203, first blanking cavity 203, first blanking cavity 203, first blanking cavity 203, first blanking cavity 203, first blanking cavity 203, first blanking cavity 203, first blanking cavity 203, first blanking cavity 203, first blanking cavity 203, first blanking Material space -404, top edge -405, first guide slope -406, second guide slope -407, second blanking hole -408, third blanking hole -409, fourth blanking space -410, fourth blanking outlet -411, main shaft -5, rotating top member -6, protruding shell -601, protruding guide groove -602, top block -7, first elastic member -8, abutment block -9, ascending guide section -901, falling section -902. DETAILED DESCRIPTION

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0019] In order to simplify the drawings, only the parts related to the invention are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically shown, or only one of them is marked. In this article, "one" not only means "only one", but also means "more than one", and "several" includes "two" and "more than two".

[0020] In this document, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] In addition, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0022] Reference Figure 1~Figure 5An embodiment of the present invention proposes a sand and gravel screening device for municipal construction, including a body 1, the body 1 has a screening space 101, the screening space 101 has a screening inlet 102; a fine screen cylinder 2 is arranged in the screening space 101, the fine screen cylinder 2 has a first material drop cavity 201, and the first material drop cavity 201 has a first material drop outlet 202; a rotating screen 3 is rotatably arranged on the fine screen cylinder 2, and the rotating screen 3 has a plurality of first material drop holes 301 in the circumferential direction, the first material drop holes 301 lead to the first material drop cavity 201, and the first material drop holes 301 are located below the screening inlet 102.

[0023] In this embodiment, sand and gravel for construction are poured in from the screening inlet 102. The rotating screen 3 starts to rotate, and the sand and gravel fall on the rotating screen 3. Sand and gravel with a particle size smaller than the first drop hole 301 enter the first drop cavity 201 through the first drop hole 301, and are finally discharged from the first drop outlet 202. Sand and gravel with larger particle sizes remain on the rotating screen 3 and continue to move. This solution has a compact structure and occupies a small space, which is suitable for the limited space conditions at the municipal construction site. The rotating design of the rotating screen 3 improves the screening efficiency and can quickly separate sand and gravel that meet the particle size requirements. It effectively realizes the preliminary particle size screening, laying the foundation for the subsequent further subdivision of sand and gravel of different particle sizes. It reduces the workload of manual screening and improves construction efficiency. It reduces the risk of construction progress delays due to untimely screening.

[0024] Furthermore, the rotating screen 3 has a first conical surface 302 , and the first blanking hole 301 is a strip hole along the radial direction of the first conical surface 302 .

[0025] In this embodiment, after the sand and gravel are poured in, they fall on the rotating screen 3 of the first conical surface 302. As the rotating screen 3 rotates, the sand and gravel roll and slide on the conical surface, and the sand and gravel smaller than the size of the strip hole enters the first blanking cavity 201 through the strip-shaped first blanking hole 301. The design of the first conical surface 302 allows the sand and gravel to naturally disperse and roll around, increasing the chance of contact with the first blanking hole 301 and improving the screening efficiency. Compared with the circular hole, the design of the strip hole can provide a larger effective screening channel on the same area, further accelerating the screening speed. The combination of the conical surface and the strip hole helps to reduce the accumulation and blockage of sand and gravel on the rotating screen 3, ensuring the smooth progress of the screening process. The structural design makes the screening more uniform, improves the screening quality, and ensures that the particle size of the screened sand and gravel meets the requirements better.

[0026] Furthermore, the screening space 101 also has a second blanking outlet 103 and a third blanking outlet 104, and also includes a separation screen 4, which is arranged in the screening space 101, and the separation screen 4 has an inner shell 401 and an outer shell 402, a second blanking space 403 is formed between the inner shell 401 and the fine screen cylinder 2, and a third blanking space 404 is formed between the outer shell 402 and the inner wall of the screening space 101, the second blanking space 403 is connected with the outside through the second blanking outlet 103, and the third blanking space 404 is connected with the outside through the third blanking outlet 104, and the top between the inner shell 401 and the outer shell 402 has a top edge 405, and the top edge 405 is located below the rotating screen 3.

[0027] In this embodiment, the sand and gravel after preliminary screening by the rotating screen 3 fall to the top edge 405. Due to the centrifugal force, gravity and inertia generated by the rotation, the sand and gravel with smaller particle size are mainly affected by gravity when the inertia is small, and fall into the second blanking space 403 between the inner shell 401 and the fine screen cylinder 2, and are discharged through the second blanking outlet 103; while the sand and gravel with larger particle size and larger inertia overcome the gravity barrier, continue to roll outward, and finally fall into the third blanking space 404 between the outer shell 402 and the inner wall of the screening space 101, and are discharged from the third blanking outlet 104. Screening is performed based on the force generated by rotation, making full use of physical principles, reducing additional power consumption, and saving energy and protecting the environment. Relying on the natural action of gravity and inertia to achieve the separation of sand and gravel of different particle sizes, the reliability and stability of screening are improved, and the possibility of equipment failure is reduced. This natural screening method makes the particle size distinction more accurate, improves the screening quality of sand and gravel, and meets the high-precision requirements of municipal construction for sand and gravel particle size. No complex control mechanism is required to adjust the screening process, which reduces the manufacturing cost and maintenance difficulty of the equipment. The space is effectively utilized, so that the entire screening device can achieve efficient multi-stage screening functions within a limited volume and adapt to various conditions at municipal construction sites.

[0028] Furthermore, a first guiding inclined surface 406 is provided between the top edge portion 405 and the outer shell portion 402 , and a second guiding inclined surface 407 is provided between the top edge portion 405 and the inner shell portion 401 .

[0029] In this embodiment, the sand and gravel after preliminary screening by the rotating screen 3 falls to the top edge 405. Under the action of the centrifugal force, gravity and inertia generated by the rotation, the sand and gravel with smaller particle size smoothly falls into the second blanking space 403 along the second guide slope 407; the sand and gravel with larger particle size rolls into the third blanking space 404 along the first guide slope 406. The setting of the first guide slope 406 and the second guide slope 407 enables the sand and gravel to slide more smoothly into the corresponding blanking space under the action of gravity and inertia, reduces the jamming and blockage of the sand and gravel during the separation process, and improves the screening efficiency. The guide slope helps to more accurately guide the sand and gravel of different particle sizes into the corresponding space, enhancing the accuracy and reliability of the screening. The flow path of the sand and gravel is optimized, the impact and wear of the sand and gravel on the separation screen 4 are reduced, and the service life of the equipment is extended. The entire screening process is made smoother and more stable, and the problem of uneven screening caused by poor flow of sand and gravel is reduced.

[0030] Furthermore, the first guide slope 406 has a second blanking hole 408, the second guide slope 407 has a third blanking hole 409, and a fourth blanking space 410 is formed between the outer shell 402 and the inner shell 401. The second blanking hole 408 and the third blanking hole 408 both lead to the fourth blanking space 410, and the fourth blanking space 410 has a fourth blanking outlet 411.

[0031] In this embodiment, when the sand and gravel slide along the guide slope under the action of gravity, inertia and centrifugal force, some of the sand and gravel with smaller particle sizes will enter the fourth drop space 410 through the second drop hole 408 and the third drop hole 409, and finally be discharged from the fourth drop outlet 411. The particle size of the sand and gravel is further subdivided, the screening accuracy is increased, and more diverse municipal construction needs can be met. The separation effect of sand and gravel with different particle sizes is improved, and the mixing of sand and gravel with different particle sizes is reduced. The fourth drop space 410 and the corresponding drop holes are set up to make full use of the internal space of the device and make the structure more compact. It can more effectively recycle and utilize sand and gravel with smaller particle sizes, and improve the utilization rate of sand and gravel resources.

[0032] Furthermore, the first guiding inclined surface 406 and the second guiding inclined surface 407 are both conical surfaces, and the second blanking hole 408 and the third blanking hole 409 are both strip holes along the radial direction.

[0033] In this embodiment, during the screening process of sand and gravel, due to the design of the conical surface, the sand and gravel can be distributed and slid more evenly. Under the action of gravity and inertia, sand and gravel with smaller particle sizes are more likely to enter the fourth blanking space 410 through the radial strip holes. The design of the conical surface helps the dispersion and flow of sand and gravel, making the screening process more uniform and efficient. Compared with circular holes, the strip holes increase the effective screening area and improve the passing efficiency of small-size sand and gravel. The accumulation and blockage of sand and gravel on the guide slope are reduced, ensuring the continuity and stability of the screening. The device's screening ability for small-size sand and gravel is optimized, and the overall screening accuracy is improved.

[0034] Furthermore, it also includes a main shaft 5, which is rotatably arranged on the machine body 1 and extends into the first blanking cavity 201. The rotating screen 3 is arranged on the main shaft 5 and rotates synchronously with the main shaft 5.

[0035] In this embodiment, the main shaft 5 provides stable power transmission for the rotating screen 3, ensuring that the rotating screen 3 can rotate at a uniform and stable speed, thereby improving the screening effect and efficiency. The rotation of the rotating screen 3 is made more accurate and controllable, reducing the screening error caused by unstable rotation. It is convenient to connect with external drive equipment, simplifying the power transmission structure and reducing the occurrence rate of failures.

[0036] Furthermore, it also includes a rotating top member 6, which is arranged on the main shaft 5 and is rotatably arranged on the fine screen cylinder member 2. The rotating top member 6 has an extended shell portion 601, and the length direction of the extended shell portion 601 is along the rotation radial direction of the rotating top member 6. The extended shell portion 601 is located in the second blanking space 403, and the extended shell portion 601 has an extended guide groove 602 along the length direction; the top block 7 is slidably arranged in the extended guide groove 602; one end of the first elastic member 8 acts on the bottom wall of the extended guide groove 602, and the other end acts on the top Block 7 provides force to push the top block 7 away from the bottom wall of the extended guide groove 602; the abutment blocks 9 are arranged in a circle on the inner wall of the inner shell 401, and the abutment blocks 9 have a rising guide section 901 and a falling section 902. The rising guide sections 901 and the falling sections 902 of several abutment blocks 9 are connected end to end in sequence. The top block 7 is configured to be driven by the rotating top piece 6 to rotate and then slide and abut with the rising guide section 901 and the falling section 902 in sequence, and after leaving the falling section 902, it impacts the rising guide section 901 of the adjacent abutment block 9.

[0037] In this embodiment, the rotation of the main shaft 5 drives the rotating top member 6 to rotate, and the top block 7 rotates accordingly. After the top block 7 contacts the rising guide section 901 of the abutment block 9, it overcomes the elastic force of the first elastic member 8 and slides inward along the extended guide groove 602 under the guiding action. When the top block 7 passes through the rising guide section 901 and reaches the falling section 902, it slides outward under the action of the first elastic member 8. After leaving the falling section 902, the top block 7 impacts the rising guide section 901 of the adjacent abutment block 9. The coordinated action of the top block 7 and the abutment block 9 generates vibration, which helps to prevent sand and gravel from clogging in the second blanking space 403 and ensure smooth blanking. The screening effect of sand and gravel is enhanced, making the particle size distinction more accurate. The self-cleaning ability of the device is improved, and the adhesion and accumulation of sand and gravel on the inner shell 401 are reduced. This vibration transmission method has a simple structure, stable and reliable operation, and reduces the possibility of failure.

[0038] Furthermore, a third guiding slope 105 is provided on the top of the machine body 1 , and the screening inlet 102 is located at the bottom of the third guiding slope 105 .

[0039] In this embodiment, when performing sand and gravel screening operations, the sand and gravel to be screened are poured onto the third guide slope 105, and the sand and gravel naturally slide along the slope to the screening inlet 102 under the action of gravity. The setting of the third guide slope 105 facilitates the feeding of sand and gravel, makes the feeding process smoother, and reduces the labor intensity of manual feeding. It helps to avoid the accumulation of sand and gravel on the top of the machine body 1, and improves the efficiency and continuity of feeding. Gravity is used to guide the sand and gravel into the screening inlet 102, without the need for additional power equipment, reducing energy consumption and costs. It reduces problems such as equipment idling or blockage caused by poor feeding, and enhances the stability and reliability of the device.

[0040] Furthermore, the first material outlet 202 , the second material outlet 103 , the third material outlet 104 and the fourth material outlet 411 are arranged in pairs, facing the two sides of the machine body 1 respectively.

[0041] In this embodiment, during the screening process, sand and gravel of different particle sizes are discharged in pairs to both sides of the machine body 1 through corresponding material outlets. The paired material outlets facilitate collection and transportation operations on both sides of the machine body 1 at the same time, thereby improving the efficiency of material discharging. It is beneficial to balance the center of gravity of the device during material discharging, making the device run more stably. It is convenient to classify and store and transport sand and gravel of different particle sizes, reducing subsequent sorting work. The spatial layout is optimized, making the material discharging process more orderly, and avoiding the mixing of sand and gravel of different particle sizes during material discharging.

[0042] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A sand and gravel screening device for municipal construction, characterized in that: include: A machine body (1), the machine body (1) having a screening space (101), the screening space (101) having a screening inlet (102); A fine screen cylinder (2), the fine screen cylinder (2) being arranged in the screening space (101), the fine screen cylinder (2) having a first material dropping cavity (201), the first material dropping cavity (201) having a first material dropping outlet (202); A rotating screen member (3), the rotating screen member (3) being rotatably disposed on the fine screen cylinder member (2), the rotating screen member (3) having a plurality of first material dropping holes (301) in a circumferential direction, the first material dropping holes (301) leading to the first material dropping cavity (201), and the first material dropping holes (301) being located below the screening inlet (102).

2. A sand and gravel screening device for municipal construction according to claim 1, characterized in that: The rotating screen element (3) has a first conical surface (302), and the first blanking hole (301) is a strip-shaped hole along the radial direction of the first conical surface (302).

3. A sand and gravel screening device for municipal construction according to claim 1, characterized in that: The screening space (101) further comprises a second material outlet (103) and a third material outlet (104), and further comprises: A separation screen element (4), wherein the separation screen element (4) is arranged in the screening space (101), and the separation screen element (4) comprises an inner shell portion (401) and an outer shell portion (402), wherein a second blanking space (403) is formed between the inner shell portion (401) and the fine screen cylinder element (2), and a third blanking space (404) is formed between the outer shell portion (402) and the inner wall of the screening space (101), wherein the second blanking space (403) is connected to the outside through the second blanking outlet (103), and the third blanking space (404) is connected to the outside through the third blanking outlet (104), and a top edge portion (405) is provided at the top between the inner shell portion (401) and the outer shell portion (402), and the top edge portion (405) is located below the rotating screen element (3).

4. A sand and gravel screening device for municipal construction according to claim 3, characterized in that: A first guiding inclined surface (406) is provided between the top edge portion (405) and the outer shell portion (402), and a second guiding inclined surface (407) is provided between the top edge portion (405) and the inner shell portion (401).

5. A sand and gravel screening device for municipal construction according to claim 4, characterized in that: The first guiding inclined surface (406) has a second blanking hole (408), the second guiding inclined surface (407) has a third blanking hole (409), a fourth blanking space (410) is formed between the outer shell part (402) and the inner shell part (401), the second blanking hole (408) and the second blanking hole (408) both lead to the fourth blanking space (410), and the fourth blanking space (410) has a fourth blanking outlet (411).

6. A sand and gravel screening device for municipal construction according to claim 5, characterized in that: The first guiding inclined surface (406) and the second guiding inclined surface (407) are both conical surfaces, and the second blanking hole (408) and the third blanking hole (409) are both strip holes along the radial direction.

7. A sand and gravel screening device for municipal construction according to claim 3, characterized in that: Also includes: A main shaft (5), the main shaft (5) being rotatably arranged on the machine body (1) and extending into the first blanking cavity (201); the rotating screen element (3) being arranged on the main shaft (5) and rotating synchronously with the main shaft (5).

8. A sand and gravel screening device for municipal construction according to claim 7, characterized in that: Also includes: a rotating top member (6), the rotating top member (6) being arranged on the main shaft (5) and being rotatably arranged on the fine screen cylinder member (2), the rotating top member (6) having an outwardly extending shell portion (601), the length direction of the outwardly extending shell portion (601) being along the radial direction of rotation of the rotating top member (6), the outwardly extending shell portion (601) being located in the second blanking space (403), and the outwardly extending shell portion (601) having an outwardly extending guide groove (602) along the length direction; A top block (7), the top block (7) being slidably disposed in the outwardly extending guide groove (602); a first elastic member (8), one end of the first elastic member (8) acting on the bottom wall of the outwardly extending guide groove (602), and the other end of the first elastic member (8) acting on the top block (7) to provide a force for moving the top block (7) away from the bottom wall of the outwardly extending guide groove (602); Abutment blocks (9), wherein the abutment blocks (9) are arranged in a circle on the inner wall of the inner shell portion (401), the abutment blocks (9) having a rising guide section (901) and a falling section (902), the rising guide sections (901) and the falling sections (902) of the abutment blocks (9) being connected end to end in sequence, and the top block (7) being configured to be driven by the rotating top member (6) to rotate and then slide and abut against the rising guide section (901) and the falling section (902) in sequence, and to impact the rising guide section (901) of the adjacent abutment block (9) after leaving the falling section (902).

9. A sand and gravel screening device for municipal construction according to claim 1, characterized in that: The top of the machine body (1) is provided with a third guiding inclined surface (105), and the screening inlet (102) is located at the bottom of the third guiding inclined surface (105).

10. A sand and gravel screening device for municipal construction according to claim 5, characterized in that: The first blanking outlet (202), the second blanking outlet (103), the third blanking outlet (104) and the fourth blanking outlet (411) are all arranged in pairs, facing respectively towards two sides of the machine body (1).

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