High-precision sandstone automatic screening machine for dry-mixed mortar
The screening assembly, composed of multiple drum screens, utilizes the rotation of the drum screens to achieve grading and screening of sand and gravel, solving the problem of insufficient screening of sand and gravel in existing technologies, improving screening accuracy and production efficiency, and featuring a compact structure and easy collection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZUNYI FUXINGYUAN BUILDING MATERIALS CO LTD
- Filing Date
- 2025-05-21
- Publication Date
- 2026-06-23
AI Technical Summary
Existing dry mortar production equipment has poor screening effect when screening sand and gravel, especially when the amount of sand and gravel is large. This results in sand and gravel of different particle sizes being discharged from the outlet without being fully screened, which affects the screening accuracy.
The screening assembly consists of multiple drum screens. The drum screens gradually reduce the diameter and length of the screen holes from the inside out. The drum screens are driven to rotate by the drive mechanism, causing the sand and gravel to tumble and be thrown up during the screening process. The sand and gravel with a particle size smaller than the screen hole are screened to the outer layer in stages, while the sand and gravel with a larger particle size remain in the inner layer and move towards the discharge end, thus achieving graded screening.
It improves the accuracy and efficiency of sand and gravel screening, occupies a small area, has a compact structure, facilitates the centralized collection and subsequent processing of sand and gravel of different particle sizes, reduces the discharge of unscreened sand and gravel, and improves production efficiency.
Smart Images
Figure CN224389264U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of sand and gravel screening technology, and specifically relates to a high-precision automatic sand and gravel screening machine for dry mortar. Background Technology
[0002] Dry-mix mortar is a granular or powdery mixture made by uniformly mixing cement, sand, mineral admixtures, and functional additives in a dry state at a professional manufacturer in a specific ratio. It can be used directly after adding water according to the prescribed proportions. In the production of dry-mix mortar, the manufactured sand used in ordinary dry-mix mortar is generally smaller than 3mm; the extra-fine sand used in special dry-mix mortar has a particle size of 0.3mm to 0.6mm. The particle size of the sand and gravel has a significant impact on the performance of dry-mix mortar.
[0003] To better achieve the screening of sand and gravel, patent CN210207526U discloses a sand and gravel screening device for dry mortar production equipment. This device includes a casing, a sand and gravel raw material inlet, and a fine sand outlet. Both the raw material inlet and the fine sand outlet are located in the middle of the casing. Below the raw material inlet, a primary screening device and a secondary screening device are sequentially arranged. The primary screening device, from top to bottom, includes a receiving plate, a primary preliminary screen, a primary secondary screen, and a primary outlet opposite the bottom of the primary and secondary screens. The primary preliminary screen and the receiving plate are symmetrically arranged along the horizontal cross-section of the casing. The folding and tilting direction of the primary and secondary screens is the same as that of the receiving plate. A primary guide plate is parallel to the bottom of the primary preliminary screen, with its bottom end opposite the top of the primary and secondary screens. This device, by arranging the various levels of screens vertically inside the casing, ensures thorough screening of sand and gravel raw materials while reducing the footprint. However, during the screening process, this equipment mainly relies on gravity to make the sand and gravel slide down. Sand and gravel of different sizes are screened during the sliding process. When the amount of sand and gravel is large, the sand and gravel at the top is very likely to be discharged from the discharge port without being screened, which leads to poor screening effect. Utility Model Content
[0004] The present invention aims to provide a high-precision automatic sand and gravel screening machine for dry mortar, so as to improve the accuracy of sand and gravel screening.
[0005] This solution discloses a high-precision automatic sand and gravel screening machine for dry mortar, comprising a support frame and a screening component rotatably connected to the support frame. The support frame is equipped with a drive mechanism that drives the screening component to rotate. The screening component includes multiple axially continuous drum screens, which are nested sequentially from the inside out and are coaxial. A gap is left between adjacent drum screens for sand and gravel to pass through. Each drum screen is provided with screen holes, the diameter of which gradually decreases from the inside out, and the length of which gradually decreases from the inside out. The discharge ends of the multiple drum screens are located on the same side.
[0006] The working principle and beneficial effects of this scheme are as follows: During operation, the drive mechanism drives multiple drum screens in the screening assembly to rotate around their axes. The sand and gravel to be screened enter the innermost drum screen from the feed end of the screening assembly. Due to the rotation of the drum screen, the sand and gravel are continuously tumbled, thrown up, and fell inside. In this process, sand and gravel with a particle size smaller than the screen aperture of the innermost drum screen will fall through the screen holes into the gap between the adjacent outer drum screen and that layer of drum screen; while sand and gravel with a particle size larger than the screen aperture of the innermost drum screen will remain in that layer of drum screen and move towards the discharge end as the drum screen rotates. Similarly, sand and gravel falling into the gaps of the outer drum screens will, under the action of the rotation of that layer of drum screens, continue to fall into the gaps of even outermost drum screens with a particle size smaller than the screen aperture of that layer of drum screens, while larger-sized sand and gravel will continue to move towards the discharge end in that layer. Because the screen apertures of multiple drum screens gradually decrease in size from the inside out and the length gradually shortens from the inside out, and the discharge ends are located on the same side, sand and gravel of different particle sizes will be discharged from different drum screen discharge ends, thus achieving the grading and screening of sand and gravel.
[0007] This solution utilizes the rotation of the drum screen to ensure that sand and gravel are fully tumbled and screened during the screening process, effectively preventing sand and gravel from being discharged from the outlet before being fully screened due to a large input volume, thus greatly improving the accuracy of sand and gravel screening. Secondly, the structural design of multiple drum screens nested sequentially from the inside out and coaxially ensures high-precision screening while making full use of space, resulting in a more compact structure and smaller footprint for the screening machine. Furthermore, because the length of the drum screen gradually shortens from the inside out, sand and gravel of different particle sizes can be screened under appropriate screening paths, and the discharge ends are located on the same side, facilitating centralized collection and subsequent processing of sand and gravel of different particle sizes, thereby improving production efficiency.
[0008] Furthermore, the screening machine also includes a fixed plate. The ends of the multiple drum screens furthest from the discharge end are detachably connected to the fixed plate. The fixed plate has through holes that communicate with the innermost drum screen and are coaxial. The diameter of the through holes is smaller than the inner diameter of the drum screen. A rotating shaft is located inside the innermost drum screen and is coaxial with it. Both ends of the rotating shaft extend outside the drum screen and are rotatably connected to a support. The output end of the drive mechanism is fixedly connected to one end of the rotating shaft. Multiple connecting rods are fixedly connected to the rotating shaft in a radial pattern. All connecting rods are located within the through holes, and the ends of the connecting rods furthest from the rotating shaft are fixedly connected to the sidewall of the through holes. By detachably connecting the drum screens to the fixed plate, the loading and unloading of the drum screens is facilitated. The connection between the rotating shaft and the fixed plate via radial connecting rods enhances the stability of the connection between the rotating shaft and the fixed plate, allowing for more stable synchronous rotation of multiple drum screens when the drive mechanism drives the rotating shaft.
[0009] Furthermore, the support is equipped with a feed hopper, the discharge end of which extends into the through hole. The feed hopper provides a centralized feeding channel for sand and gravel, improving screening efficiency and overall production efficiency.
[0010] Furthermore, the end of the rotating shaft near the feed hopper is integrally formed with a shoulder, and multiple connecting rods are fixedly connected to the shoulder. The shoulder provides a stable connection point for the connecting rods. Compared to directly connecting the connecting rods to the cylindrical surface of the rotating shaft, the integrally formed shoulder can withstand greater torque and force; and the shoulder design prevents sand and gravel entering from the feed hopper from directly impacting the rotating shaft, which helps to improve the service life of the rotating shaft.
[0011] Furthermore, the drive mechanism includes a motor and a reducer. The input end of the reducer is connected to the output end of the motor, and the output end of the reducer is connected to one end of the rotating shaft. The combination of the motor and the reducer allows for adjustment of the screening speed according to actual screening requirements.
[0012] Furthermore, each rotary drum screen includes a screen mesh and two fixing rings. The screen mesh is drum-shaped, with screen holes evenly distributed on it. Both ends of the screen mesh are fixedly connected to the two fixing rings. The fixing plate has the same number of fixing grooves as the rotary drum screen at its end facing the screen. Multiple fixing rings of the rotary drum screen, located away from the discharge end, are detachably connected to their respective fixing grooves. The rotary drum screen employs a combination structure of screen mesh and fixing rings, facilitating the manufacture and installation of the screen mesh. Simultaneously, the fixing rings provide reliable support and fixation for the screen mesh, ensuring its shape stability during rotation. The fixing grooves on the fixing plate cooperate with the fixing rings of the rotary drum screen, further simplifying the connection between the rotary drum screen and the fixing plate and improving the loading and unloading efficiency of the rotary drum screen.
[0013] Furthermore, the outer wall of the fixing plate is provided with multiple fixing holes, each of which communicates with multiple fixing grooves. A fixing ring located within a fixing groove has multiple connecting holes of the same diameter as the fixing holes. A screw is installed within each fixing hole, and the end of the screw passes through the connecting holes of different drum screens in sequence and is threadedly connected to the fixing plate. By threading the screw through the connecting holes on the fixing ring and connecting it to the fixing plate, multiple drum screens are firmly fixed to the fixing plate, enhancing the connection strength between the drum screens and the fixing plate. During the operation of the screening machine, this effectively prevents the drum screens from loosening or shifting, ensuring the overall stability of the screening assembly. This connection method facilitates the disassembly and adjustment of the drum screens. When it is necessary to replace a drum screen or adjust the relative position between drum screens, simply unscrew the screw; the operation is simple and quick.
[0014] Furthermore, the outer walls of the fixing rings near the discharge end of multiple drum screens are integrally formed with annular bosses. Multiple support plates are fixedly connected to the bracket, and the top of each support plate is provided with an arc-shaped groove that mates with the corresponding annular boss. The cooperation between the annular bosses and the arc-shaped grooves provides a stable support structure for the discharge end of the drum screens, distributing the weight and centrifugal force generated during the rotation of the drum screens, reducing the load on the shaft and fixing plates, and extending the service life of the shaft, fixing plates, and other related components. The cooperation between the arc-shaped grooves and the annular bosses also provides a certain positioning function for the drum screens, ensuring accurate positioning of multiple drum screens at the discharge end, facilitating the subsequent collection and processing of sand and gravel of different particle sizes.
[0015] Furthermore, the outer wall of the fixing plate is also integrally formed with an annular boss, and a support plate for supporting the fixing plate is fixedly connected to the bracket. The top of the support plate is also provided with an arc-shaped groove that cooperates with the annular boss on the fixing plate. The annular boss on the outer wall of the fixing plate, which cooperates with the support plate on the bracket, further enhances the stability of the fixing plate, so that the fixing plate can be reliably supported while supporting multiple drum screens, reducing the deformation and shaking of the fixing plate during the operation of the screening machine.
[0016] Furthermore, the screening machine also includes a connecting plate with a stepped hole at its center. One end of the rotating shaft passes through the stepped hole and is rotatably connected to the support. The end of the rotating shaft near the connecting plate also has an integrally formed shoulder, on which multiple connecting rods are fixedly connected. These connecting rods are arranged radially, and the ends of the connecting rods furthest from the rotating shaft are all fixedly connected to the side wall of the smaller section of the stepped hole. The diameter of the smaller end of the stepped hole is equal to the inner diameter of the innermost screen. The fixing ring of the innermost drum screen near the discharge end is detachable. The connecting plate is connected to the larger end of the stepped hole; the end of the connecting plate facing the drum screen is provided with a multi-layer limiting hole group with one less layer than the number of drum screens. Each layer of limiting hole group includes multiple limiting holes, and the multiple limiting holes in the same layer are located on the same circumference. Except for the fixing ring of the innermost drum screen near the discharge end, multiple limiting rods are fixedly connected to each other. The multiple limiting rods on the same fixing ring extend into the corresponding limiting holes in the same layer. Multiple screws are threadedly connected to the outer wall of the connecting plate, and the multiple screws pass through the corresponding limiting rods on different fixing rings. By using the stepped holes to engage with the innermost drum screen's fixing ring, the limiting hole group to engage with the limiting rod, and the screw connection, precise positioning and secure fixing of multiple drum screen discharge ends are achieved. This enhances the stability of the screening components at the discharge end, effectively preventing axial displacement or swaying of the drum screen during rotation and ensuring the accuracy of sand and gravel screening. The rotating shaft and connecting plate are connected by a shaft shoulder and a connecting rod, further improving the connection strength and stability between the rotating shaft and the connecting plate. When the drive mechanism drives the rotating shaft to rotate, it can more reliably drive the drum screen to rotate synchronously.
[0017] Furthermore, the outer wall of the connecting plate is also integrally formed with an annular boss, and a support plate is fixedly connected to the bracket. The top of the support plate is provided with an arc-shaped groove that cooperates with the annular boss. The annular boss on the outer wall of the connecting plate cooperates with the arc-shaped groove of the support plate on the bracket, providing stable support for the connecting plate, sharing the load borne by the connecting plate when supporting the discharge end of the drum screen, and further enhancing the stability of the entire screening assembly.
[0018] Furthermore, belt conveyors are installed directly below the discharge ends of multiple rotary drum screens. The installation of belt conveyors enables automated collection and transportation of sand and gravel of different particle sizes, eliminating the need for frequent manual collection, reducing labor intensity, and improving production efficiency. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the structure of a high-precision automatic sand and gravel screening machine for dry mortar, which is an embodiment of this utility model.
[0020] Figure 2 for Figure 1 A partial sectional view of the connection between the central fixing ring, fixing plate, and rotating shaft on the left side.
[0021] Figure 3This is a schematic diagram of the structure of a high-precision automatic sand and gravel screening machine for dry mortar, which is an embodiment 2 of this utility model.
[0022] Figure 4 This is a schematic diagram of the structure of a high-precision automatic sand and gravel screening machine for dry mortar, which is an embodiment 3 of this utility model.
[0023] Figure 5 This is a schematic diagram of the structure of a high-precision automatic sand and gravel screening machine for dry mortar, which is an embodiment 4 of this utility model. Detailed Implementation
[0024] The following detailed description illustrates the specific implementation method:
[0025] The reference numerals in the accompanying drawings of the instruction manual include: base 1, support column 2, support plate 3, fixing ring 4, annular boss 5, screen 6, rotating shaft 7, screw 8, fixing plate 9, feed hopper 10, shaft shoulder 11, reducer 12, motor 13, through hole 14, connecting rod 15, belt conveyor 16, connecting plate 17, and limit rod 18.
[0026] Example 1 is basically as shown in the appendix. Figures 1-2 As shown: A high-precision automatic sand and gravel screening machine for dry mortar includes a fixed plate 9, a rotating shaft 7, a support, and a screening component rotatably connected to the support. The support is equipped with a drive mechanism that drives the screening component to rotate. Specifically: the support includes a base 1 and two pillars 2 fixedly connected to the base 1. The two ends of the rotating shaft 7 are rotatably connected to the two pillars 2 respectively. The drive mechanism includes a motor 13 and a reducer 12 installed on the base 1. The input end of the reducer 12 is connected to the output end of the motor 13, and the output end of the reducer 12 is connected to one end of the rotating shaft 7. The end of the rotating shaft 7 away from the reducer 12 has an integrally formed shoulder 11. Five connecting rods 15 are fixedly connected to the shoulder 11, and the five connecting rods 15 are arranged radially.
[0027] The screening assembly includes four axially continuous drum screens, which are nested sequentially from the inside out and are coaxial. There is a gap between adjacent drum screens to allow sand and gravel to pass through. The length of the drum screens gradually decreases from the inside to the outside, and the discharge ends of the multiple drum screens are located on the same side. Each drum screen consists of a screen 6 and two fixing rings 4. The screen 6 is drum-shaped and has screen holes evenly distributed on it. The two ends of the screen 6 are fixedly connected to the two fixing rings 4 respectively. The aperture of the screen holes on the screen 6 gradually decreases from the inside to the outside.
[0028] The fixed plate 9 is provided with a through hole 14, which is connected to the innermost drum screen and the two are coaxial. The diameter of the through hole 14 is smaller than the inner diameter of the innermost drum screen. The two ends of the rotating shaft 7 pass through the innermost drum screen and are rotatably connected to the support. The rotating shaft 7 is coaxial with the drum screen. All five connecting rods 15 are located in the through hole 14. The ends of the five connecting rods 15 away from the rotating shaft 7 are fixedly connected to the side wall of the through hole 14. A feed hopper 10 is installed on the support column 2 away from the reducer 12. The discharge end of the feed hopper 10 extends into the through hole 14.
[0029] The fixed plate 9 has four fixing grooves on the end facing the drum screen. The fixing rings 4 of the four drum screens away from the discharge end are detachably connected to the corresponding fixing grooves. Specifically, the outer wall of the fixed plate 9 has three fixing holes, each of which is connected to the four fixing grooves. The fixing rings 4 located in the fixing grooves have three connecting holes with the same diameter as the fixing holes. The fixing holes are equipped with screws 8. The ends of the screws 8 pass through the connecting holes of different drum screens in sequence and are threadedly connected to the fixed plate 9.
[0030] The outer walls of the fixed plate 9 and the four fixed rings 4 near the discharge end of the drum screen are all integrally formed with annular bosses 5. Five support plates 3 are fixedly connected to the base 1. The top of each support plate 3 is provided with an arc groove that cooperates with the corresponding annular boss 5. The annular boss 5 can rotate in the arc groove.
[0031] The specific implementation process is as follows: The motor 13 is started, and its output power is transmitted to the reducer 12. After the reducer 12 adjusts the speed, it drives the rotating shaft 7 to rotate. The rotation of the rotating shaft 7 drives the fixed plate 9 and the four drum screens connected to the fixed plate 9 to rotate synchronously. The sand and gravel to be screened are poured into the feed hopper 10, and the sand and gravel enter the innermost drum screen through the through-hole 14. As the drum screen rotates, the sand and gravel are continuously tumbled, thrown up, and fell within the innermost drum screen. Sand and gravel with a particle size smaller than the aperture of the innermost drum screen will fall through the screen holes into the gap between the adjacent outer drum screen and this layer of drum screen; while sand and gravel with a particle size larger than the aperture of the innermost drum screen will remain within this layer of drum screen and move towards the discharge end as the drum screen rotates. Similarly, sand and gravel falling into the gaps of the outer drum screen will continue to fall into the gaps of the outermost drum screen as the drum screen rotates. Sand and gravel with a particle size smaller than the screen aperture of that layer will continue to fall into the gaps of the outermost drum screen, while larger particles will continue to move towards the discharge end in that layer. Since the screen apertures of the four drum screens gradually decrease in size and length from the inside to the outside, and the discharge ends are located on the same side, sand and gravel of different sizes will be discharged from the discharge ends of different drum screens, completing the screening process.
[0032] Example 2 is basically as shown in the appendix. Figure 3As shown, the only difference between this and Embodiment 1 is that the base 1 is thicker, and the top of the base 1 is tilted. After the automatic screening machine is installed, the discharge end of the drum screen is lower than the feed end. During the screening process, because the top of the base 1 is tilted, and the discharge end of the drum screen is lower than the feed end after the automatic screening machine is installed, the sand and gravel inside the drum screen will not only tumble, be thrown up, and fall due to the rotation of the drum screen, but will also move towards the discharge end more quickly under the action of gravity.
[0033] Example 3 is basically as shown in the appendix. Figure 4 As shown, the only difference between this embodiment and Embodiment 2 is that a belt conveyor 16 is installed directly below the discharge ends of the four drum screens. When sand and gravel of different sizes are discharged from their respective drum screen discharge ends, they fall directly onto the corresponding belt conveyor 16. The belt conveyor 16 automatically transports the sand and gravel of different sizes to the designated location for collection, thereby improving production efficiency.
[0034] Example 4 is basically as shown in the appendix. Figure 5 As shown, the only difference from Embodiment 1 is that: there are only two support plates 3, and none of the four drum screen fixing rings 4 are provided with annular bosses 5; in addition, it also includes a connecting plate 17, with a stepped hole through the center of the connecting plate 17. The end of the rotating shaft 7 away from the feed hopper 10 passes through the stepped hole and is rotatably connected to the support column 2. The end of the rotating shaft 7 near the connecting plate 17 is also integrally formed with a shoulder 11, and five connecting rods 15 are fixedly connected to the shoulder 11. The five connecting rods 15 are radial, and the ends of the five connecting rods 15 away from the rotating shaft 7 are all fixedly connected to the side wall of the smaller section of the stepped hole; the diameter of the smaller end of the stepped hole is the same as the inner diameter of the innermost screen 6, and the innermost drum screen is fixed near the discharge end. The fixed ring 4 is detachably connected to the larger end of the stepped hole; the end of the connecting plate 17 facing the drum screen is provided with three layers of limiting hole groups, each layer of limiting hole group includes three limiting holes, and the three limiting holes in the same layer are located on the same circumference. Except for the fixed ring 4 of the innermost drum screen near the discharge end, three limiting rods 18 are fixedly connected to each other. The three limiting rods 18 on the same fixed ring 4 extend into the corresponding limiting holes in the same layer; three screws 8 are threadedly connected to the outer wall of the connecting plate 17, and the three screws 8 pass through the corresponding limiting rods 18 on different fixed rings 4; the outer wall of the connecting plate 17 is also integrally formed with an annular boss 5, and the annular bosses 5 on the connecting plate 17 and the fixed plate 9 respectively overlap in the arc grooves of the two support plates 3.
[0035] The specific implementation process is as follows: The implementation process is the same as in Example 1, except that: the fixing ring 4 of the innermost drum screen near the discharge end is detachably connected to the larger end of the stepped hole of the connecting plate 17. The fixing rings 4 of the other drum screens near the discharge end are connected to the limiting hole group on the connecting plate 17 through the limiting rod 18, and are threaded to the connecting plate 17 through the screw 8, thereby realizing the precise positioning and firm fixation of the discharge ends of multiple drum screens.
[0036] The only difference between Example 5 and Example 4 is that: the base 1 is thicker, the top of the base 1 is tilted, and after the automatic screening machine is installed, the discharge end of the drum screen is lower than the feed end.
[0037] The only difference between Example 6 and Example 5 is that belt conveyors 16 are provided directly below the discharge ends of the four drum screens.
[0038] The only difference between Example 7 and Example 4 is that belt conveyors 16 are provided directly below the discharge ends of the four drum screens.
[0039] The only difference between Example 8 and Example 1 is that belt conveyors 16 are provided directly below the discharge ends of the four drum screens.
[0040] In addition, in order to further improve the smoothness of the rotation of the annular boss 5 in the arc groove, rollers can be installed on the circumferential surface of the annular boss 5 to improve the smoothness of the contact surface.
[0041] The above descriptions are merely embodiments of this utility model, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of this utility model, and these should also be considered within the scope of protection of this utility model. These modifications will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application shall be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.
Claims
1. A high-precision automatic sand and gravel screening machine for dry mortar, comprising a support frame and a screening assembly rotatably connected to the support frame, wherein the support frame is provided with a drive mechanism for rotating the screening assembly; characterized in that: The screening assembly includes multiple axially continuous drum screens, which are nested sequentially from the inside out and are coaxial. Gaps for sand and gravel passage are left between adjacent drum screens. Each drum screen has screen holes with gradually decreasing apertures from the inside out, and the length of the drum screen gradually decreases from the inside out. The discharge ends of the multiple drum screens are located on the same side. The screening machine also includes a fixed plate. The ends of the multiple drum screens furthest from the discharge end can be detachably connected to the fixed plate. The fixed plate has through holes that communicate with the innermost drum screen and are coaxial. The aperture of the through holes is smaller than the inner diameter of the drum screen. A rotating shaft is located inside the innermost drum screen and is coaxial with it. Both ends of the rotating shaft extend outside the drum screen and are rotatably connected to a support. The output end of the drive mechanism is fixedly connected to one end of the rotating shaft. Multiple connecting rods are fixedly connected to the rotating shaft in a radial pattern. All connecting rods are located within the through holes, and the ends of the connecting rods furthest from the rotating shaft are fixedly connected to the side wall of the through holes.
2. The high-precision automatic sand and gravel screening machine for dry mortar according to claim 1, characterized in that: The support is equipped with a feeding hopper, and the discharge end of the feeding hopper extends into the through hole.
3. The high-precision automatic sand and gravel screening machine for dry mortar according to claim 2, characterized in that: The rotating shaft has an integrally formed shoulder at one end near the feed hopper, and multiple connecting rods are fixedly connected to the shoulder.
4. The high-precision automatic sand and gravel screening machine for dry mortar according to claim 3, characterized in that: The drive mechanism includes a motor and a reducer. The input end of the reducer is connected to the output end of the motor, and the output end of the reducer is connected to one end of the rotating shaft.
5. The high-precision automatic sand and gravel screening machine for dry mortar according to claim 4, characterized in that: Each rotary screen includes a screen mesh and two fixing rings. The screen mesh is in the shape of a drum, and the screen holes are evenly distributed on the screen mesh. Both ends of the screen mesh are fixedly connected to the two fixing rings respectively. The fixing plate has a fixing groove with the same number of grooves as the rotary screen at the end facing the rotary screen. The fixing rings of the multiple rotary screens away from the discharge end are detachably connected to the corresponding fixing grooves.
6. The high-precision automatic sand and gravel screening machine for dry mortar according to claim 5, characterized in that: The outer wall of the fixing plate is provided with multiple fixing holes, each of which is connected to multiple fixing grooves. The fixing ring located in the fixing groove is provided with multiple connecting holes of the same diameter as the fixing holes. A screw is provided in the fixing hole, and the end of the screw passes through the connecting holes of different drum screens in sequence and is threadedly connected to the fixing plate.
7. A high-precision automatic sand and gravel screening machine for dry mortar according to claim 6, characterized in that: The outer walls of the fixing rings near the discharge end of the multiple rotary screens are integrally formed with annular bosses. Multiple support plates are fixedly connected to the bracket, and the top of each support plate is provided with an arc-shaped groove that cooperates with the corresponding annular boss.
8. A high-precision automatic sand and gravel screening machine for dry mortar according to claim 6, characterized in that: The screening machine also includes a connecting plate with a stepped hole at its center. One end of the rotating shaft passes through the stepped hole and is rotatably connected to the support. The end of the rotating shaft near the connecting plate also has an integrally formed shoulder, on which multiple connecting rods are fixedly connected. These connecting rods are arranged radially, and the ends of the connecting rods furthest from the rotating shaft are fixedly connected to the side wall of the smaller section of the stepped hole. The diameter of the smaller end of the stepped hole is equal to the inner diameter of the innermost screen. The fixing ring of the innermost drum screen near the discharge end is detachably connected. At the larger end of the stepped hole; the end of the connecting plate facing the drum screen is provided with a multi-layer limiting hole group with one less layer than the number of drum screens. Each layer of limiting hole group includes multiple limiting holes, and the multiple limiting holes in the same layer are located on the same circumference. Except for the fixing ring of the innermost drum screen near the discharge end, multiple limiting rods are fixedly connected to each other. The multiple limiting rods on the same fixing ring extend into the corresponding limiting holes in the same layer. Multiple screws are threadedly connected to the outer wall of the connecting plate, and the multiple screws all pass through the corresponding limiting rods on different fixing rings.
9. A high-precision automatic sand and gravel screening machine for dry mortar according to any one of claims 1 to 8, characterized in that: Each of the aforementioned rotary drum screens is equipped with a belt conveyor directly below its discharge end.