A double screw sealing structure of a loss-in-weight scale

Abstract

The utility model discloses a kind of double-screw sealing structures of weightlessness scale, including ball hopper, connecting body, feed pipe, conveying screw, the one end of connecting body is set power motor, the other end is connected feed pipe, conveying screw is set inside feed pipe;Oil seal structure is set between connecting body and feed pipe;Ball hopper connection is set on feed pipe, and the feed inlet position of ball hopper connection on feed pipe is set a push material distance between oil seal structure, and conveying screw extends into push material distance position close to oil seal structure, so that the push material distance forms a screw backflush material space.Ball hopper is connected on feed pipe, and push material distance is set between feed inlet position and oil seal structure, and conveying screw's spiral blade in the backflush material space also has setting, can block most powder to the penetration of connecting body one end, then by oil seal sealing trace amount of material, reach better sealing effect.

Description

Technical Field

[0001] This utility model relates to the field of loss-in-weight scale technology, specifically to a twin-screw sealing structure for a loss-in-weight scale. Background Technology

[0002] In the field of twin-screw seals for loss-in-weight scales, existing sealing structures mainly include direct oil seals and gas seals. However, both of these sealing methods have significant drawbacks, as follows:

[0003] Defects of oil seal sealing: Oil seal sealing involves installing 1-2 oil seals at the end of the screw shaft. Because the screw is horizontally installed, material inevitably comes into contact with the oil seals. While oil seals provide a good seal for larger particles (such as granules), they can gradually penetrate the sealing lip of the oil seal over time, especially with fine powders. This penetration accumulates and eventually damages the seal's performance, leading to failure and preventing effective sealing of the powder. This not only affects the normal operation of the loss-in-weight scale but can also cause material leakage, resulting in environmental pollution, material waste, increased maintenance costs, and the risk of production interruptions.

[0004] Disadvantages of Gas Seals: Gas seals, also known as gas-sealed systems, prevent material leakage, especially of powders, by introducing a slightly positive pressure gas through a screw. While this sealing method is effective for powders, it suffers from structural complexity. It requires an additional positive pressure gas source system, which not only increases the overall complexity of the equipment but also significantly raises costs. The additional gas source system occupies more space, increasing the difficulty of installation and maintenance, as well as energy consumption and operating costs. This limits the application of gas seals in situations where cost and space are limited.

[0005] In view of the above, it is necessary to propose a twin-screw sealing structure for loss-in-weight scales to solve the above problems. Utility Model Content

[0006] The purpose of this invention is to overcome the defects in the existing technology and provide a new twin-screw sealing structure for loss-in-weight scales. This structure must simultaneously meet the sealing requirements for granules and powders, effectively protect the oil seal from damage by the powder, and overcome the shortcomings of existing sealing structures, thereby reducing costs and simplifying the structure.

[0007] To achieve the above objectives, the technical solution of this utility model is as follows: A double-screw sealing structure for a loss-in-weight scale includes a ball hopper, a connecting body, a conveying pipe, and a conveying screw. One end of the connecting body is equipped with a power motor, and the other end is connected to the conveying pipe. The conveying screw is installed inside the conveying pipe. An oil seal structure is installed between the connecting body and the conveying pipe. The ball hopper is connected to the conveying pipe, and a pushing distance is set between the inlet position of the ball hopper connected to the conveying pipe and the oil seal structure. The conveying screw extends into the pushing distance position close to the oil seal structure, so that the pushing distance forms a space for the screw to backflush material.

[0008] Furthermore, the connecting body includes a connecting seat, on which a mounting hole for rotatable connection of the twin screws is provided. A mounting groove is provided at the end of the mounting hole facing the conveying pipe. An oil seal seat is provided in the mounting groove. The inner ring of the oil seal seat is provided with an oil seal body corresponding to each conveying screw, and the outer ring of the oil seal seat is provided with a sealing ring.

[0009] Furthermore, the inner wall of the conveying pipe in the backflushing material space is a straight inner wall in the axial direction, and the radius of the spiral blades of the conveying screw in the backflushing material space is the same size radius from head to tail.

[0010] Furthermore, the inner wall of the backflushing material space is a conical inner wall, and the radius gradually increases from the connecting body end to the feed inlet. The spiral blades of the conveying screw in the backflushing material space form conical outer contour spiral blades that cooperate with the conical inner wall.

[0011] Furthermore, the radius of the screw shaft of the conveying screw in the backflushing material space gradually increases from the feed inlet to the connecting body end, so that the annular gap between the screw shaft and the inner wall of the backflushing material space gradually decreases.

[0012] Furthermore, the pitch of the spiral blades of the conveying screw in the backflushing material space is smaller than the pitch of the spiral blades at the feed inlet.

[0013] Furthermore, the inner wall of the backflushing material space and the surface of the conveying screw are provided with a smooth surface layer.

[0014] Furthermore, the pushing distance is not less than 1 / 2 of the radius of the hopper.

[0015] The advantages and beneficial effects of this utility model are as follows:

[0016] 1. When the ball bucket is connected to the conveying pipe, a pushing distance is set between the inlet and the oil seal structure. The spiral blades of the conveying screw are also set in the backflow material space, which can block most of the powder from penetrating to one end of the connector. The oil seal then seals the small amount of material that has passed through, achieving a better sealing effect.

[0017] 2. In the backflushing material space, when the inner wall is flat, the radius of the screw blades of the conveying screw remains consistent in the axial direction, and the pitch in the backflushing material space is smaller than that at the feed inlet, which can improve the powder conveying efficiency and reduce the backflow of powder into the connecting seat; when the inner wall is conical, the powder will be subjected to the component force pointing towards the screw shaft and the discharge end during the movement, which, combined with the conveying screw's conveying of the powder, further strengthens the blocking effect on the powder; the radius of the screw shaft gradually increases from the feed inlet to the connecting body end, so that the annular gap between the screw shaft and the inner wall of the backflushing material space gradually decreases, which can also strengthen the blocking effect on the powder entering.

[0018] 3. The inner wall of the backflushing material space and the surface of the conveying screw are provided with a smooth surface layer, such as polishing the blade surface to make it smoother, or coating the blade surface with a special coating (such as polytetrafluoroethylene coating) to reduce surface roughness, so that the powder is not easy to stick to it and avoid material accumulation. Attached Figure Description

[0019] Figure 1 This is an isometric view of a double-screw sealing structure for a loss-in-weight scale according to this utility model;

[0020] Figure 2 This is a longitudinal cross-sectional schematic diagram of the twin-screw sealing structure of the loss-in-weight scale of this utility model;

[0021] Figure 3 This is an exploded view of a double-screw sealing structure for a loss-in-weight scale according to this utility model;

[0022] Figure 4 This is one of the schematic diagrams of the backflushing material space in this utility model;

[0023] Figure 5 This is the second schematic diagram of the backflushing material space in this utility model;

[0024] In the diagram: 1. Ball bucket; 2. Connector; 3. Conveying pipe; 4. Conveying screw; 5. Power motor; 6. Oil seal structure; 7. Pushing distance; 8. Connecting seat; 9. Mounting hole; 10. Mounting groove; 11. Oil seal seat; 12. Oil seal body; 13. Sealing ring; 14. Flat inner wall; 15. Conical inner wall; 16. Conical outer contour; 17. Screw shaft; 18. Feed inlet; 19. Spiral blade. Detailed Implementation

[0025] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solution of this utility model and should not be construed as limiting the scope of protection of this utility model.

[0026] A twin-screw sealing structure for a loss-in-weight scale, such as Figures 1-5As shown, the assembly includes a ball hopper 1, a connecting body 2, a conveying pipe 3, and a conveying screw 4. One end of the connecting body 2 is equipped with a power motor 5, and the other end is connected to the conveying pipe 3. The conveying screw 4 is installed inside the conveying pipe 3. The output end of the power motor 5 is connected to the connecting body 2. Both the connecting body 2 and the power motor 5 are fixedly installed on the metering platform. The power motor 5 has a gear set inside. The connecting body 2 is used to transmit the power of the power motor 5 to the conveying screw 4 and to prevent the lubricating oil in the gear set from passing through. Therefore, an oil seal structure 6 is provided inside the connecting body 2. Specifically, an oil seal structure 6 is provided between the connecting body 2 and the conveying pipe 3. The conveying pipe 3 is connected to the side of the connecting body 2 away from the power motor 5, so that the conveying screw 4 driven by the power motor 5 rotates inside the conveying pipe 3 to realize the conveying of materials. It can be understood that in actual use, there is no restriction on the use of a single screw or a twin screw.

[0027] The oil seal structure 6 described in this embodiment is as follows: Figure 2 , 3 As shown, the connecting body 2 includes a connecting seat 8. The connecting seat 8 has a through hole for the output shaft of the power motor 5 to pass through, and a mounting hole 9 for a double screw to rotate and connect to it at one end. The mounting hole 9 has a mounting groove 10 facing the feed pipe 3. The mounting groove 10 has an oil seal seat 11. The shape of the mounting groove 10 matches the oil seal seat 11. The inner ring of the oil seal seat 11 has an oil seal body 12 corresponding to each feed screw 4. The inner ring of the oil seal seat 11 facing the power motor 5 has an oil seal body 12. After installation, the oil seal seat 11 and the bottom surface of the mounting groove 10 form a mounting cavity for the oil seal body 12, so that the oil seal body 12 can be sleeved on the power output shaft to block the lubricating oil in the gearbox from passing through. The outer ring of the oil seal seat 11 has a sealing ring 13, which is used to seal the other side between the oil seal seat 11 and the feed pipe 3. When the bolts are tightened and fixed, the sealing ring 13 seals the connection gap.

[0028] like Figure 1 As shown, the ball bucket 1 is connected to the conveying pipe 3. The difference is that the inlet 18 of the ball bucket 1 connected to the conveying pipe 3 is separated from the oil seal structure 6 by a pushing distance 7, so that the inlet 18 is a certain distance away from the connecting seat 8. Figure 2As shown, the conveying screw 4 extends into the pushing distance 7 near the oil seal structure 6, forming a screw backflow material space. In this embodiment, the spiral blades 19 of the conveying screw 4 are also installed within this backflow material space. When conveying powder, after it falls from the inlet 18, the conveying screw 4 within the pushing distance 7 can push the powder towards the outlet, thus preventing most of the powder from penetrating to the connecting body 2. This significantly reduces the probability of powder entering the oil seal structure 6, protecting the oil seal. Finally, the oil seal seals any remaining traces of material, achieving the required sealing effect. It is understood that the pushing distance 7 should be kept at a certain length to achieve a good powder blocking effect. In actual use, the pushing distance 7 can be set to be no less than 1 / 2 of the radius of the hopper 1. Of course, the pushing distance 7 should not be too long, as this would reduce the conveying efficiency of the conveying screw 4. Therefore, this distance can be controlled to be no greater than the radius of the hopper 1.

[0029] As one example, such as Figure 2 As shown in the enlarged view, the inner wall of the conveying pipe 3 in the backflushing material space is a straight inner wall 14 in the axial direction. Specifically, if a single screw is used, the inner wall of the backflushing material space is a cylindrical structure; a twin screw can also be used, in which case the straight inner wall 14 in the backflushing material space corresponds to two parallel and side-connected cylindrical structures, and a conveying screw 4 is set in each cylindrical inner wall; the radius of the spiral blades 19 of the conveying screw 4 in the backflushing material space is the same size from head to tail. Since the inner wall of the backflushing material space in this embodiment is a straight inner wall 14 in the axial direction, the radius of the spiral blades 19 on the conveying screw 4 remains consistent in the axial direction.

[0030] A further design involves making the pitch of the spiral blades 19 of the conveying screw 4 within the backflushing material space smaller than the pitch of the spiral blades 19 at the feed inlet 18. Based on the characteristics of the powder, the relatively smaller pitch within the backflushing material space improves the conveying efficiency of the powder within this space, thereby reducing powder backflow into the connecting seat 8. In this embodiment, solid spiral blades 19 are used; the thick blades can withstand the impact and wear of large-diameter materials, ensuring the screw's service life. Simultaneously, the spiral surface of the solid blades should be smooth to facilitate the sliding conveying of large-diameter materials.

[0031] Specifically, the inner wall of the backflushing material space and the surface of the conveying screw 4 are provided with a smooth surface layer. To reduce the adhesion and accumulation of powder on the blade surface, the surface of the solid helical blade 19 can be specially treated. For example, the blade surface can be polished to be smoother, reducing surface roughness, so that powder is less likely to stick to it. Alternatively, a special coating can be plated on the blade surface to form a smooth surface layer, such as a polytetrafluoroethylene coating. This coating has an extremely low coefficient of surface friction, so that powder falling on it is like water droplets falling on a lotus leaf, easily sliding off, thus avoiding material accumulation. It is also advisable to provide the same smooth surface layer for the inner wall of the backflushing material space.

[0032] In another embodiment, the inner wall of the backflushing material space is a conical inner wall 15, such as... Figure 4 As shown, the radius gradually increases from the end of the connecting body 2 to the feed inlet 18. The spiral blades 19 of the conveying screw 4 in the backflushing material space form a conical outer contour 16 spiral blade 19 that matches the conical inner wall 15. In this embodiment, when the powder moves from the feed inlet 18 to the end of the connecting body 2, it will be blocked by the conical inner wall 15. The force analysis of the powder after reaching the conical inner wall 15 is as follows: under the action of the conical inner wall 15, the powder receives a component force F1 pointing towards the screw shaft 17 and a component force F2 pointing towards the discharge end. Thus, the conical inner wall 15 can form a certain blocking effect on the powder. Combined with the conveying screw 4 conveying the powder, the blocking effect on the powder is strengthened.

[0033] In another embodiment, the radius of the screw shaft 17 of the conveying screw 4 in the backflushing material space gradually increases from the feed inlet 18 to the end of the connecting body 2, such as... Figure 5 As shown, the annular gap between the screw shaft 17 and the inner wall of the backflushing material space gradually decreases. Similar to the principle of the aforementioned embodiment, the inner wall of the backflushing material space in this embodiment uses a straight inner wall 14, while the baseline of the screw shaft 17 of the conveying screw is set to a structure with a gradually changing radius, such as... Figure 5 As shown by the dashed line, the radius of the screw shaft 17 near the end of the connector 2 gradually increases, thereby gradually decreasing its distance from the flat inner wall 14, thus enhancing its blocking effect on the entry of powder.

[0034] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A twin-screw sealing structure for a loss-in-weight scale, characterized in that, The device includes a ball bucket (1), a connecting body (2), a conveying pipe (3), and a conveying screw (4). One end of the connecting body (2) is equipped with a power motor (5), and the other end is connected to the conveying pipe (3). The conveying screw (4) is installed inside the conveying pipe (3). An oil seal structure (6) is installed between the connecting body (2) and the conveying pipe (3). The ball bucket (1) is connected to the conveying pipe (3), and a pushing distance (7) is set between the inlet (18) of the ball bucket (1) connected to the conveying pipe (3) and the oil seal structure (6). The conveying screw (4) extends into the pushing distance (7) and is close to the oil seal structure (6), so that the pushing distance (7) forms a space for the screw to backflush material.

2. The twin-screw sealing structure for a loss-in-weight scale according to claim 1, characterized in that, The connector (2) includes a connector (8), and a mounting hole (9) for rotating connection of the twin screws is provided on the connector (8). The mounting hole (9) is provided with a mounting groove (10) at one end facing the conveying pipe (3). An oil seal seat (11) is provided in the mounting groove (10). The inner ring of the oil seal seat (11) is provided with an oil seal body (12) corresponding to each conveying screw (4). The outer ring of the oil seal seat (11) is provided with a sealing ring (13).

3. The twin-screw sealing structure for a loss-in-weight scale according to claim 1, characterized in that, The inner wall of the conveying pipe (3) in the backflushing material space is a straight inner wall (14) in the axial direction, and the radius of the spiral blades (19) of the conveying screw (4) in the backflushing material space is the same from head to tail.

4. The twin-screw sealing structure for a loss-in-weight scale according to claim 1, characterized in that, The inner wall of the backflushing material space is a conical inner wall (15), and the radius gradually increases from the end of the connector (2) to the feed inlet (18). The spiral blades (19) of the conveying screw (4) in the backflushing material space form a conical outer contour (16) spiral blade (19) that matches the conical inner wall (15).

5. The twin-screw sealing structure for a loss-in-weight scale according to claim 1, characterized in that, The radius of the screw shaft (17) of the conveying screw (4) in the backflushing material space gradually increases from the feed inlet (18) to the end of the connecting body (2), so that the annular gap between the screw shaft (17) and the inner wall of the backflushing material space gradually decreases.

6. The twin-screw sealing structure for a loss-in-weight scale according to claim 1, characterized in that, The pitch of the spiral blades (19) of the conveying screw (4) in the backflushing material space is smaller than the pitch of the spiral blades (19) at the feed inlet (18).

7. The twin-screw sealing structure for a loss-in-weight scale according to claim 6, characterized in that, The inner wall of the backwash material space and the surface of the conveying screw (4) are provided with a smooth surface layer.

8. The twin-screw sealing structure for a loss-in-weight scale according to claim 1, characterized in that, The pushing distance (7) is not less than 1 / 2 of the radius of the hopper (1).

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