A screw feeder sealing structure and a screw feeder comprising the same

Abstract

The utility model discloses a kind of sealing structure of screw feeder and the screw feeder comprising it, including outer cover, sealing seat, packing cover, sealing ring assembly and packing, the one end of sealing seat is connected with the outer end surface of the shell of screw feeder, the other end of sealing seat connects packing cover, sealing ring assembly and packing are radially filled between sealing seat and screw rod, the inside of sealing seat has the stop ring of butt joint with packing end, packing cover is pressed in the other end of packing;Sealing seat, sealing ring assembly and shell form gas cavity, the surface of sealing seat is equipped with the gas injection hole towards gas cavity and directly opposite the junction of shell and screw rod;Opening is equipped on the outer cover, and gas pipe is inserted into.The utility model adopts air seal, sealing ring seal and packing seal three kinds of sealing mode combination to ensure sealing effect, while gas injection hole directly opposite gas cavity and the junction of shell and screw rod, so that there can be fast in gas cavity Larger pressure prevents material from entering gas cavity.

Description

Technical Field

[0001] This utility model relates to the field of material conveying technology, and in particular to a sealing structure for a screw feeder and a screw feeder including the same. Background Technology

[0002] Screw feeders use helical blades on a screw to quantitatively transport materials. The screw passes through the housing and is driven to rotate by a motor outside the housing. Therefore, the screw and the housing are in a movable fit. If a simple bearing fit is used, material leakage (especially of powder materials) is likely to occur. Therefore, a sealing structure needs to be set on the outside of the housing.

[0003] Traditional sealing structures use stuffing boxes, but stuffing boxes have a short service life and are unsuitable for sealing fine materials. Patent number CN202022952199 describes a sealing structure designed by the applicant for a disc feeder. This structure introduces the concept of a gas seal; however, the gas delivery path is relatively long, and the gas is mainly delivered to the annular relief groove, making it unsuitable for sealing the end of a screw feeder housing. Because the material mainly moves outwards during the rotation of a disc feeder, less material leaks towards the central shaft. Therefore, this gas delivery structure is sufficient to prevent the small amount of material leaking towards the central shaft. However, the end of a screw feeder housing is close to the inlet, and the material volume is relatively large, making the aforementioned gas delivery structure unsuitable.

[0004] Currently, screw feeders with high sealing requirements on the market all directly purchase finished mechanical seals, which are expensive and inconvenient to disassemble and maintain. In addition, the mechanical seal uses the principle of skeleton oil seal. Since it contains metal parts, after the screw rotates for a long time, the metal material is easily worn out. If the worn-out metal material enters the shell and mixes with the material, it will cause the material to be contaminated.

[0005] Therefore, it is necessary to design a sealing structure for screw feeders that is low-cost, pollution-free, and has a good sealing effect. Utility Model Content

[0006] To address the technical problems of insufficient sealing effect, high cost, or easy contamination of materials when using existing sealing structures in screw feeders, this utility model provides a screw feeder sealing structure and a screw feeder containing the same to solve the above problems.

[0007] This utility model proposes a sealing structure for a screw feeder, including an outer cover and a sealing seat, a packing cover, a sealing ring assembly, and a packing ring located inside the outer cover. One end of the sealing seat is connected to the outer end face of the screw feeder housing, and the other end of the sealing seat is connected to the packing cover. The sealing ring assembly and the packing ring are radially filled between the sealing seat and the screw. The inner side of the sealing seat has a retaining ring that abuts against the end of the packing ring, and the packing cover is pressed against the other end of the packing ring. The sealing seat, the sealing ring assembly, and the housing form an air chamber. The surface of the sealing seat is provided with an air jet hole facing the air chamber and directly opposite the connection between the housing and the screw. The outer cover is provided with an opening for the air supply pipe to extend into.

[0008] In an optional embodiment of this utility model, the sealing seat includes a cylindrical body and flange faces located at both ends of the cylindrical body, wherein the two flange faces are connected to the end faces of the shell and the packing cover.

[0009] In an optional embodiment of this utility model, the end of the cylinder near the shell is a horn-shaped variable diameter section, and the jet hole is located on the horn-shaped variable diameter section.

[0010] In an optional embodiment of this utility model, the sealing ring assembly includes a bushing fitted on the screw and a U-shaped sealing ring pressed between the bushing and the sealing seat, wherein the ends of the bushing abut against the housing and the retaining ring respectively.

[0011] In an optional embodiment of this utility model, V-shaped sealing rings are provided at both ends of the bushing, and the lips of the two V-shaped sealing rings abut against the housing and the retaining ring respectively.

[0012] In an optional embodiment of this utility model, the outer cover has one or more mounting ports, which are closed by a protective cover.

[0013] In an optional embodiment of this utility model, the end face of the retaining ring that contacts the packing is an inclined surface, and the inclined surface gradually slopes towards the sealing ring assembly from the outside to the inside.

[0014] In an optional embodiment of this utility model, the opening of the U-shaped sealing ring faces the side where the air cavity is located.

[0015] In an optional embodiment of this utility model, the sealing seat and the packing cover are made of plastic.

[0016] This utility model also proposes a screw feeder, including the screw feeder sealing structure described above.

[0017] The beneficial effects of this utility model are: (1) This utility model adopts a combination of three sealing methods: gas seal, sealing ring seal and packing seal to ensure the sealing effect. At the same time, the jet hole is directly facing the air chamber and the connection between the shell and the screw, so that the air chamber can quickly generate a large pressure to prevent the material from entering the air chamber.

[0018] (2) This utility model has a simple structure, low manufacturing cost, and no metal parts, so it will not contaminate materials. Attached Figure Description

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0020] Figure 1 This is an axial sectional view of a specific embodiment of the screw feeder described in this utility model; Figure 2 yes Figure 1 Enlarged view of point a in the middle.

[0021] In the diagram, 1. Outer cover, 2. Sealing seat, 201. Retaining ring, 202. Cylinder, 203. Flange face, 3. Packing cover, 4. Sealing ring assembly, 401. Bushing, 402. U-shaped sealing ring, 5. Packing, 6. Screw conveyor section, 601. Housing, 7. Sealing section, 8. Drive section, 801. Outer shell, 9. Screw, 10. Air chamber, 11. Air jet hole, 12. Opening, 13. Horn-shaped reducing section, 14. V-shaped sealing ring, 15. Inclined surface, 16. Mounting port, 17. Protective cover. Detailed Implementation

[0022] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0023] Example 1 A sealing structure for a screw feeder, used in a screw feeder, such as... Figure 1 As shown, the screw feeder includes a screw conveying section 6, a sealing section 7, and a drive section 8. The screw conveying section 6 is the part that conveys materials. The housing 601 of the screw conveying section 6 is connected to the sealing section 7. The drive section 8 is equipped with a drive motor and a coupling. One end of the screw 9 is connected to the output shaft of the drive motor, and the other end passes through the sealing section 7 and extends into the screw conveying section 6.

[0024] like Figure 2As shown, the sealing part 7 includes an outer cover 1 and a sealing seat 2, a packing cap 3, a sealing ring assembly 4, and a packing 5 located inside the outer cover 1. The two ends of the outer cover 1 are respectively connected to the outer shell 801 of the drive part 8 and the shell 601 of the screw conveyor part 6. The sealing components are located in the cavity formed by the outer cover 1, the shell 601, and the outer shell 801. One end of the sealing seat 2 is connected to the outer end face of the shell 601, and the other end of the sealing seat 2 is connected to the packing cap 3. The sealing ring assembly 4 and the packing 5 are radially filled between the sealing seat 2 and the screw 9, which plays a double sealing role. The inner side of the sealing seat 2 has a retaining ring 201 that abuts against the end of the packing 5. The packing cap 3 is pressed against the other end of the packing 5, and the packing 5 is axially fixed by the retaining ring 201 and the packing cap 3. The sealing seat 2, the sealing ring assembly 4, and the shell 601 form an air cavity 10. The surface of the sealing seat 2 is provided with an air jet hole 11 facing the air cavity 10 and directly opposite the connection between the shell 601 and the screw 9. The outer cover 1 is provided with an opening 12 for the air supply pipe to extend into.

[0025] The jet hole 11 is a through hole that passes through the sealing seat 2. External gas is injected into the air chamber 10 through the air pipe and the jet hole 11, which generates positive pressure in the air chamber 10. Compared with the gas channel in the prior art, the structure of the jet hole 11 is simple and easy to process. The gas is injected into the air chamber 10 at a faster speed. Furthermore, since the jet hole 11 is directly opposite the connection between the housing 601 and the screw 9, the material accumulated at the end of the housing 601 inside the spiral conveying part 6 will not leak into the air chamber 10 under the action of gas injection.

[0026] In this invention, the air jet 11 blowing air into the air chamber 10 forms the first air seal, the sealing ring assembly 4 forms the second seal, and the packing 5 forms the third seal. The air jet 11 is directly formed on the outer cover 1. The positive pressure inside the air chamber 10 reduces material leakage. Even if there is a small amount of leakage, the sealing ring assembly 4 can block the material, which will then re-enter the housing 601 under the positive pressure inside the air chamber 10. The packing 5 serves as the final layer of protection and is normally inactive, mainly providing enhanced protection. For example, when used for conveying highly polluting materials, even a tiny leak can cause environmental pollution. These sealing methods do not place high demands on the structural strength of the sealing seat 2; therefore, the sealing seat 2 can be made of plastic material, preventing the presence of metallic impurities.

[0027] Sealing seat 2: The sealing seat 2 includes a cylindrical body 202 and flange faces 203 located at both ends of the cylindrical body 202. The two flange faces 203 are respectively connected to the end faces of the housing 601 and the packing cover 3. Figure 2 As shown, the right flange face 203 of the sealing seat 2 is in contact with the end of the housing 601, and the left flange face 203 of the sealing seat 2 may not be in contact with the packing cover 3. The inner circumference of the packing cover 3 extends into the cylinder 202 and abuts against the packing 5. The distance between the packing cover 3 and the flange face 203 can be adjusted according to the number of packing 5.

[0028] Sealing ring assembly 4: The sealing ring assembly 4 includes a bushing 401 fitted onto the screw 9 and a U-shaped sealing ring 402 pressed between the bushing 401 and the sealing seat 2. The ends of the bushing 401 abut against the housing 601 and the retaining ring 201, respectively. The bushing 401 and the screw 9 are clearance-fitted and can rotate relative to each other. The opening 12 of the U-shaped sealing ring 402 preferably faces the housing 601. The bushing 401 and the cylinder 202 press against the inner and outer sides of the U-shaped sealing ring 402, respectively, causing the opening 12 of the U-shaped sealing ring 402 to deform, thereby achieving a sealing effect.

[0029] Example 2 Based on Embodiment 1, this embodiment designs the arrangement of the jet holes 11 as follows: Figure 2 As shown, the end of the cylinder 202 near the shell 601 is a horn-shaped variable diameter section 13, and the jet hole 11 is located on the horn-shaped variable diameter section 13. At this time, the jet hole 11 can penetrate the horn-shaped variable diameter section 13 along the normal direction. The design of the horn-shaped variable diameter section 13 can make the cross-section of the air chamber 10 gradually increase towards the shell 601, so that the air chamber 10 has more gas volume and greater pressure at the end of the shell 601.

[0030] Example 3 Based on Embodiment 1, V-shaped sealing rings 14 are provided at both ends of the bushing 401, and the lips of the two V-shaped sealing rings 14 abut against the housing 601 and the retaining ring 201, respectively. The support ring of the V-shaped sealing ring 14 has a good supporting function, and its lip has a self-sealing function, which provides a good sealing effect when used in rotating parts.

[0031] Example 4 Based on the above embodiment, the end face of the retaining ring 201 that contacts the packing 5 is a slope 15, which gradually slopes from the outside to the inside towards the sealing ring assembly 4. Figure 2 As shown, the radial inner side of the inclined surface 15 is inclined towards the sealing ring assembly 4. Since there is a gap between the retaining ring 201 and the screw 9, the design of the inclined surface 15 can extend the inner side of the packing 5 to the gap between the retaining ring 201 and the screw 9.

[0032] Example 5 Compared to the other two sealing components, the packing 5 is a consumable part that needs to be replaced regularly. To facilitate the replacement of the packing 5, the outer cover 1 also has one or more mounting ports 16, which are closed by the protective cover 17. Under normal circumstances, the protective cover 17 is closed, and the mounting ports 16 are located near the packing cover 3, allowing the packing cover 3 to be removed and the packing 5 replaced through the mounting ports 16.

[0033] In this specification, the illustrative expressions of the terms do not necessarily refer to the same embodiments. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments.

[0034] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A sealing structure for a screw feeder, characterized in that: Includes an outer cover (1) and a sealing seat (2), a packing cover (3), a sealing ring assembly (4), and a packing (5) located inside the outer cover (1). One end of the sealing seat (2) is connected to the outer end face of the housing (601) of the screw feeder, and the other end of the sealing seat (2) is connected to the packing cover (3). The sealing ring assembly (4) and the packing (5) are radially filled between the sealing seat (2) and the screw (9). The inner side of the sealing seat (2) has a retaining ring (201) that abuts against the end of the packing (5). The packing cover (3) is pressed against the other end of the packing (5). The sealing seat (2), sealing ring assembly (4) and housing (601) form an air chamber (10). The surface of the sealing seat (2) is provided with a jet hole (11) facing the air chamber (10) and directly opposite the connection between the housing (601) and the screw (9). The outer cover (1) is provided with an opening (12) into which the air supply pipe extends.

2. The sealing structure of the screw feeder according to claim 1, characterized in that: The sealing seat (2) includes a cylinder (202) and flange faces (203) located at both ends of the cylinder (202). The two flange faces (203) are connected to the end faces of the shell (601) and the packing cover (3).

3. The sealing structure of the screw feeder according to claim 2, characterized in that: The end of the cylinder (202) near the shell (601) is a horn-shaped variable diameter section (13), and the jet hole (11) is located on the horn-shaped variable diameter section (13).

4. The sealing structure of the screw feeder according to claim 1, characterized in that: The sealing ring assembly (4) includes a bushing (401) fitted on the screw (9) and a U-shaped sealing ring (402) pressed between the bushing (401) and the sealing seat (2). The ends of the bushing (401) abut against the housing (601) and the retaining ring (201) respectively.

5. The sealing structure of the screw feeder according to claim 4, characterized in that: The bushing (401) is provided with V-shaped sealing rings (14) at both ends, and the lips of the two V-shaped sealing rings (14) abut against the housing (601) and the retaining ring (201) respectively.

6. The sealing structure of the screw feeder according to claim 1, characterized in that: The outer cover (1) has one or more mounting ports (16), which are closed by a protective cover (17).

7. The sealing structure of the screw feeder according to claim 1, characterized in that: The end face of the retaining ring (201) that contacts the packing (5) is an inclined surface (15), which gradually slopes from the outside to the inside towards the sealing ring assembly (4).

8. The sealing structure of the screw feeder according to claim 4, characterized in that: The opening (12) of the U-shaped sealing ring (402) faces the side where the air chamber (10) is located.

9. The sealing structure of the screw feeder according to claim 1, characterized in that: The sealing seat (2) and the packing cover (3) are made of plastic.

10. A screw feeder, characterized in that: The screw feeder sealing structure includes any one of claims 1-9.

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