Bottom shaft sealing device of mixer and conical mixer

Abstract

This invention relates to a bottom shaft sealing device for a mixer and a conical mixer. The bottom shaft sealing device includes: a base plate with an opening; a main shaft, the bottom of which rotatably extends through the opening, with a retaining ring fitted on the main shaft; a sealing seat, a portion of which can be inserted into the opening and forms an annular cavity with the outer wall of the main shaft; an upper annular gap is formed between the upper inner wall of the portion and the outer wall of the main shaft, and the retaining ring is located directly above the portion and forms a top gap with the top surface of the portion; an air ring and an oil seal assembly arranged vertically are provided in the annular cavity, the air ring having an airflow channel, and the sealing seat also having an air inlet channel, which communicates with the upper annular gap and the air inlet channel; and a bearing seat fitted on the lower end of the main shaft and connected to the bottom of the sealing seat, with a bearing installed between the bearing seat and the main shaft. This invention effectively solves the problem of material leakage easily occurring at the bottom shaft seal of existing mixers.

Description

Technical Field

[0001] This invention relates to the field of sealing, and more particularly to a bottom shaft sealing device for a mixer and a conical mixer. Background Technology

[0002] Natural high-purity graphite, due to its excellent electrical conductivity, high-temperature resistance, corrosion resistance, and self-lubricating properties, has wide applications in various industries. In traditional industries, high-purity graphite is used to manufacture crucibles, sealing materials, and corrosion-resistant equipment. In the new energy sector, high-purity graphite is a key raw material for manufacturing lithium-ion battery anode materials, and market demand continues to grow with the increasing popularity of electric vehicles and portable electronic devices. Furthermore, high-purity graphite also has important applications in the nuclear industry, aerospace, and electronic information fields, such as in the manufacture of nuclear reactor components and integrated circuit substrates.

[0003] With the continuous expansion of the production of natural high-purity graphite, in order to solve the problems of uniformity of natural graphite and stability of high-purity graphite materials, conical mixers have emerged. Due to the structural characteristics of the conical mixer itself, and the fact that the particle size of natural high-purity graphite reaches the micron level, the material is very easy to leak from the bottom of the mixer. As a result, material leakage occurs at the bottom shaft seal during equipment operation. Material leakage not only wastes raw materials but also pollutes the on-site environment, which is detrimental to the occupational health of personnel. In addition, it causes the bearings at the shaft end to burn out due to graphite falling into them.

[0004] Currently, the traditional method for sealing the shaft end of a conical mixer is to use a packing seal. Due to the inherent characteristics of natural high-purity graphite, material leakage often occurs along the main shaft. Over time, the leakage increases. Although the leakage can be controlled by pressing the main shaft packing seal, if the tightening is too tight, the bearing may be damaged due to high temperature caused by friction, affecting normal production. Summary of the Invention

[0005] The purpose of this invention is to provide a bottom shaft seal device for a mixer and a conical mixer, which can effectively solve the problem of material leakage at the bottom shaft seal of existing mixers.

[0006] The objective of this invention can be achieved using the following technical solutions: This invention provides a bottom shaft sealing device for a mixer, comprising: a horizontally arranged base plate with an opening; a vertically arranged main shaft, the bottom of which rotatably protrudes through the opening, and a retaining ring sleeved on the main shaft and above the base plate; an annular sealing seat, sealingly installed below the base plate and sleeved on the bottom of the main shaft; a portion of the sealing seat can be inserted into the opening and can form an annular cavity with the outer wall of the main shaft; an upper annular gap is formed between the upper inner wall of the portion of the structure and the outer wall of the main shaft, the upper annular gap communicating with the annular cavity; the retaining ring is located directly above the portion of the structure and forms a top gap with the top surface of the portion of the structure; an air ring and an oil seal assembly arranged vertically are provided in the annular cavity, the air ring having an airflow channel, and the sealing seat also having an air inlet channel, the airflow channel communicating with the upper annular gap and the air inlet channel; a bearing seat, sleeved on the lower end of the main shaft and connected to the bottom of the sealing seat, and a bearing is installed between the bearing seat and the main shaft.

[0007] In a preferred embodiment of the present invention, the outer periphery of the retaining ring forms a downwardly extending extension ring, and the top inner side of the partial structure has a convex ring that protrudes upwardly from the top surface of the base plate. An upper annular gap is formed between the inner wall of the convex ring and the outer wall of the main shaft, and a top gap is formed between the top surface of the convex ring and the bottom surface of the retaining ring. The lower spacer ring of the extension ring is disposed on the outer periphery of the convex ring and has a gap with the portion of the partial structure located on the outer periphery of the convex ring.

[0008] In a preferred embodiment of the present invention, the sealing seat includes a sealing main ring, a convex ring, an oil seal pressure ring, and a connecting ring frame. The upper outer diameter of the sealing main ring matches the diameter of the opening. The upper part of the sealing main ring is inserted into the opening, and the top surface of the sealing main ring is flush with the top surface of the base plate. The convex ring is connected to the inner top of the sealing main ring and protrudes upward from the top surface of the sealing main ring. The oil seal pressure ring is sealed and connected to the bottom of the sealing main ring. The bottom surface of the convex ring, the inner wall of the sealing main ring, the top surface of the oil seal pressure ring, and the outer wall of the main shaft form an annular cavity. The sealing main ring, the convex ring, and the oil seal pressure ring constitute a partial structure. The air intake channel is opened inside the sealing main ring. The connecting ring frame is sleeved and connected to the lower outer side of the sealing main ring and can be connected to the base plate and the bearing seat respectively.

[0009] In a preferred embodiment of the present invention, the upper part of a portion of the structure is made of stainless steel.

[0010] In a preferred embodiment of the present invention, an outer ring groove and an inner ring groove are respectively provided on the outer side wall and the inner side wall of the air ring. A plurality of radial holes are provided at intervals along the axial direction inside the air ring. The radial holes are connected to the outer ring groove and the inner ring groove. The outer ring groove, the inner ring groove and each radial hole constitute an airflow channel. One end of the air intake channel is connected to the outer ring groove, and the other end of the air intake channel is connected to an air pipe connector.

[0011] In a preferred embodiment of the present invention, the oil seal assembly includes a plurality of double-lip oil seals stacked sequentially along the axial direction of the main shaft. The outer wall of the double-lip oil seal is interference-fitted with the sidewall of the annular cavity, and the inner lip of the double-lip oil seal is in contact with the outer wall of the main shaft.

[0012] In a preferred embodiment of the present invention, a bearing oil seal is provided between the top of the bearing housing and the outer wall of the spindle, and the bearing oil seal is located above the bearing.

[0013] In a preferred embodiment of the present invention, an oil inlet channel is further provided in the bearing housing, which can communicate with the bearing and the bearing oil seal.

[0014] In a preferred embodiment of the present invention, the bearing housing includes an upper housing and a lower cover connected vertically. The lower end of the upper housing is an open end and its top surface is provided with a mounting hole. The upper housing is sleeved on the bottom end of the spindle, and there is a gap between the mounting hole and the outer wall of the spindle. The lower cover covers the bottom end of the spindle, and the bearing is sandwiched between the inner cavity of the upper housing and the spindle. An upper stepped hole with an increased diameter is formed at the top of the mounting hole, which communicates with the top surface of the upper housing. The bearing oil seal is installed in the upper stepped hole. An outer ring is provided on the outer wall of the upper housing, and the outer ring is connected to the sealing seat.

[0015] The present invention also provides a conical mixer, including the above-described mixer bottom shaft seal device.

[0016] As described above, the bottom shaft sealing device and conical mixer of the present invention, at the bottom of the main shaft of the mixer, firstly, use a retaining ring to block the material, causing the material to fall onto the retaining ring or onto the outer circumference of the retaining ring, preventing it from continuing to fall directly downwards into the gap between the main shaft and the bottom plate. Secondly, by introducing compressed air into the air ring, a positive pressure environment is formed in the annular cavity above the oil seal assembly, the upper annular gap, and the top gap, which can further prevent the material from entering. Furthermore, the oil seal assembly in the annular cavity can further block the material. Thus, through the cooperation of the retaining ring, the air ring, and the oil seal assembly, a leak-proof seal at the bottom shaft seal can be basically achieved, effectively avoiding the problem of material leakage at the bottom shaft seal during equipment operation, reducing raw material waste and on-site environmental pollution, and also preventing the bearing at the shaft end from being burned due to material falling in. Attached Figure Description

[0017] The following figures are intended only to illustrate and explain the present invention and do not limit the scope of the invention. Wherein: Figure 1 This is a schematic diagram of the bottom shaft sealing device for a mixer provided by the present invention.

[0018] Figure 2 for Figure 1 A magnified view of a section at the retaining ring.

[0019] Figure 3 for Figure 1 A magnified view of a portion of the bearing oil seal.

[0020] Figure 4 This is a partial structural diagram of the bottom shaft sealing device for a mixer provided by the present invention.

[0021] Figure 5 This is a schematic diagram of the bottom shaft sealing device of the mixer provided by the present invention before the sealing seat is installed.

[0022] Figure 6 This is a schematic diagram of the structure of the bottom shaft sealing device of the mixer provided by the present invention after the sealing seat is installed.

[0023] Figure 7 This is a schematic diagram of the bottom shaft seal device of the mixer provided by the present invention after the air ring is installed.

[0024] Figure 8 This is a schematic diagram of the structure of the bottom shaft sealing device of the mixer provided by the present invention after the installation of the oil seal assembly, oil seal pressure ring and air pipe connector.

[0025] Figure 9 This is a schematic diagram of the bottom shaft sealing device of the mixer provided by the present invention before the bearing seat is installed.

[0026] Figure 10 This is a schematic diagram of the structure of the bottom shaft sealing device of the mixer provided by the present invention after installation in the bearing housing.

[0027] Explanation of icon numbers: 1. Base plate; 11. Opening; 12. Flange plate; 121. Inner hole; 2. Spindle; 21. Shoulder; 3. Retaining ring; 31. Extension ring; 32. Connecting ring; 4. Sealing seat; 41. Main sealing ring; 411. Air inlet passage; 412. Air pipe connector; 42. Convex ring; 421. Upper annular gap; 422. Top gap; 43. Oil seal pressure ring; 431. Lower annular gap; 432. Limiting ring; 44. Connecting ring frame; 441. Upper ring plate; 442. Connecting rod; 443. Lower ring plate; 5. Air ring; 51. Outer ring groove; 52. Inner ring groove; 53. Radial hole; 6. Oil seal assembly; 61. Main oil seal; 7. Bearing housing; 71. Upper housing; 711. Mounting hole; 712. Upper stepped hole; 713. Lower stepped hole; 714. Oil inlet channel; 72. Lower cover; 73. Outer ring; 74. Intermediate sleeve; 8. Bearings; 9. Bearing oil seal. Detailed Implementation

[0028] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0029] like Figures 1 to 10 As shown, this application provides a bottom shaft sealing device for a mixer, comprising: The horizontally positioned base plate 1 has an opening 11; A vertically arranged main shaft 2 has its bottom rotatably protruding through an opening 11, and a retaining ring 3 is fitted on the main shaft 2 and above the base plate 1; An annular sealing seat 4 is installed below the base plate 1 and sleeved on the bottom of the main shaft 2. Part of the sealing seat 4 can be inserted into the opening 11 and can form an annular cavity with the outer wall of the main shaft 2. An upper annular gap 421 is formed between the upper inner wall of the part and the outer wall of the main shaft 2. The upper annular gap 421 is connected to the annular cavity. The retaining ring 3 is located directly above the part and forms a top gap 422 with the top surface of the part. An air ring 5 and an oil seal assembly 6 are arranged vertically in the annular cavity. An air flow channel is provided in the air ring 5. An air intake channel 411 is also provided in the sealing seat 4. The air flow channel can be connected to the upper annular gap 421 and the air intake channel 411. The bearing housing 7 is fitted onto the lower end of the main shaft 2 and connected to the bottom of the sealing seat 4. A bearing 8 is installed between the bearing housing 7 and the main shaft 2.

[0030] Before the mixer starts operating, the device is ventilated. High-pressure air enters the upper annular gap 421 and the top gap 422 along the main shaft 2 through the air intake channel 411 and the air ring 5. When the mixer is filled with material, the material falls onto the bottom plate 1, blocking the connection between the top gap 422 and the mixer's chamber. This creates a near-sealed chamber from the oil seal assembly 6 to the top gap 422. Compressed air creates a positive pressure environment within this sealed chamber, preventing material from entering. Of course, a small amount of compressed air may enter the mixer's inner chamber through the top gap 422, but this does not affect the blocking effect.

[0031] Therefore, the bottom shaft sealing device of this application, at the bottom of the main shaft 2 of the mixer, firstly, uses the retaining ring 3 to block the material, causing the material to fall onto the retaining ring 3 or onto the outer circumference of the retaining ring 3, preventing it from continuing to fall directly downwards into the gap between the main shaft 2 and the bottom plate 1. Secondly, by introducing compressed air into the air ring 5, a positive pressure environment is formed in the annular cavity above the oil seal assembly 6, the upper annular gap 421, and the top gap 422, which can further prevent the material from entering. Furthermore, the oil seal assembly 6 in the annular cavity can further block the material. Thus, through the cooperation of the retaining ring 3, the air ring 5, and the oil seal assembly 6, a leak-proof seal at the bottom shaft seal can be basically achieved, effectively avoiding the problem of material leakage at the bottom shaft seal during equipment operation, reducing raw material waste and on-site environmental pollution, and also preventing the bearing 8 at the shaft end from being burned due to material falling in.

[0032] The mixer in this application mainly refers to a vertical mixer, which has a vertically arranged main shaft 2, the bottom of which extends downward from the base plate 1. This mixer can be, for example, a conical mixer, where the main shaft 2 is a vertical helical shaft.

[0033] Optionally, refer to Figure 1 and Figure 2 The outer periphery of the retaining ring 3 forms a downwardly extending extension ring 31. The inner side of the top of the part of the structure has a convex ring 42 that protrudes upward from the top surface of the base plate 1. An upper annular gap 421 is formed between the inner wall of the convex ring 42 and the outer wall of the main shaft 2. A top gap 422 is formed between the top surface of the convex ring 42 and the bottom surface of the retaining ring 3. The lower spacer ring of the extension ring 31 is provided on the outer periphery of the convex ring 42 and has a gap with the part of the part of the structure located on the outer periphery of the convex ring 42.

[0034] The bending gap formed by the sequential connection of the top gap 422, the gap between the extension ring 31 and the outer wall of the convex ring 42, and the gap between the bottom surface of the extension ring 31 and the part located on the outer periphery of the convex ring 42 in part of the structure can better block the entry of materials and improve the material leakage prevention effect.

[0035] The inner diameter of the retaining ring 3 should match the outer diameter of the corresponding position of the spindle 2, and the retaining ring 3 and the spindle 2 are sealed and fixedly connected. Optionally, the inner top of the retaining ring 3 extends upward to form a connecting ring 32, the top of the connecting ring 32 can abut against the shoulder 21 of the spindle 2, and the connecting ring 32 can be fixed to the spindle 2 by fasteners.

[0036] Alternatively, for ease of machining and installation of the sealing seat 4, refer to Figure 1 and Figure 2The sealing seat 4 includes a sealing main ring 41, a convex ring 42, an oil seal pressure ring 43, and a connecting ring frame 44. The upper outer diameter of the sealing main ring 41 matches the diameter of the opening 11. The upper part of the sealing main ring 41 is inserted into the opening 11, and the top surface of the sealing main ring 41 is flush with the top surface of the base plate 1. The convex ring 42 is connected to the inner top of the sealing main ring 41 and protrudes upward from the top surface of the sealing main ring 41. The oil seal pressure ring 43 is sealed and connected to the bottom of the sealing main ring 41. The bottom surface of the convex ring 42, the inner wall of the sealing main ring 41, the top surface of the oil seal pressure ring 43, and the outer wall of the main shaft 2 form an annular cavity. The sealing main ring 41, the convex ring 42, and the oil seal pressure ring 43 constitute a partial structure. The air intake channel 411 is opened inside the sealing main ring 41. The connecting ring frame 44 is sleeved and connected to the lower outer side of the sealing main ring 41 and can be connected to the base plate 1 and the bearing seat 7 respectively.

[0037] The diameter of the aforementioned opening 11 is larger than the outer diameter of the corresponding position on the main shaft 2, and the gap between them allows the upper part of the sealing main ring 41 to be inserted. The inner diameter of the sealing main ring 41 is larger than the outer diameter of the corresponding position on the main shaft 2, so that the gap between them can accommodate the gas ring 5 and the oil seal assembly 6. The inner diameter of the gas ring 5 is slightly larger than the outer diameter of the corresponding position on the main shaft 2, and a gap can be formed between it and the main shaft 2 to facilitate the smooth rotation of the main shaft 2. The oil seal pressure ring 43 can be sealed and fixed to the bottom of the sealing main ring 41 by fasteners and seals. A lower annular gap 431 is formed between the lower inner wall of part of the structure (i.e., the inner wall of the oil seal pressure ring 43) and the outer wall of the main shaft 2 to facilitate the smooth rotation of the main shaft 2. The inner diameter of the convex ring 42 is smaller than the inner diameter of the sealing main ring 41, and the outer diameter of the convex ring 42 can be larger than the inner diameter of the sealing main ring 41 but should be smaller than the top outer diameter of the sealing main ring 41. A gap is formed between the portion of the top surface of the sealing main ring 41 located outside the convex ring 42 and the bottom surface of the extension ring 31.

[0038] The connecting ring frame 44 can be integrally formed with the sealing main ring 41, or it can be fixed to the sealing main ring 41 by welding. To facilitate the fixing of the connecting ring frame 44 to the base plate 1 and the bearing seat 7, optionally, refer to... Figure 1 The connecting ring frame 44 includes an upper ring plate 441, a connecting assembly, and a lower ring plate 443, which are fixedly connected (e.g., welded) from top to bottom. The connecting assembly includes a plurality of connecting rods 442 spaced circumferentially. The outer diameters of the upper ring plate 441 and the lower ring plate 443 may be the same and larger than the outer diameter of the connecting assembly. The upper ring plate 441 is fixedly connected to the lower outer side of the sealing main ring 41. The upper ring plate 441 and the lower ring plate 443 are respectively connected to the base plate 1 and the bearing seat 7.

[0039] Optionally, to facilitate the connection between the sealing seat 4 and the base plate 1, refer to Figure 1An annular flange plate 12 is fixed to the bottom surface of the base plate 1. The inner diameter 121 of the flange plate 12 is the same as the opening diameter of the base plate 1. The upper part of the sealing main ring 41 is also inserted into the inner diameter 121 of the flange plate 12. The upper ring plate 441 rests against the flange plate 12 and is connected to the flange plate 12 by fasteners. A sealing ring is also sandwiched between the upper ring plate 441 and the flange plate 12 to ensure a seal.

[0040] Alternatively, the upper part of a portion of the structure may be made of stainless steel (austenitic stainless steel).

[0041] When the material in the mixer is graphite, excessive iron content in the graphite will lead to unqualified graphite products. This problem can be avoided by using stainless steel for the upper part of some structures, that is, the parts that may come into contact with the graphite material.

[0042] In actual processing, the sealing main ring 41 can be made according to... Figure 6 The diagram shows two fixed parts, one above the other. The upper part is made of stainless steel, and the portion of the upper part closer to the inside forms the aforementioned protruding ring 42. The lower part can be made of stainless steel, carbon steel, or other suitable materials.

[0043] Alternatively, to facilitate the smooth introduction of compressed air, refer to Figure 1 and Figure 2 An outer ring groove 51 and an inner ring groove 52 are respectively provided on the outer and inner side walls of the air ring 5. Multiple radial holes 53 are provided at intervals along the axial direction inside the air ring 5. The radial holes 53 are connected to the outer ring groove 51 and the inner ring groove 52. The outer ring groove 51, the inner ring groove 52 and each radial hole 53 form an airflow channel. One end of the air intake channel 411 is connected to the outer ring groove 51, and the other end of the air intake channel 411 is connected to an air pipe connector 412.

[0044] Optionally, the width of the outer annular groove 51 gradually decreases from the outside to the inside along the axial direction, while the width of the inner annular groove 52 gradually increases from the outside to the inside along the axial direction.

[0045] Generally, the oil seal pressure ring 43 mentioned above has a mating hole that communicates directly with the air intake channel 411, and the air pipe connector 412 is installed in the mating hole. The air pipe connector 412 may be equipped with a one-way valve to prevent gas backflow.

[0046] Nylon can be used for the material of the air ring 5, as it is low in cost. Stainless steel can also be used if necessary.

[0047] Further optional, refer to Figure 1The oil seal assembly 6 includes multiple main oil seals 61 stacked sequentially along the axial direction of the main shaft 2. The gas ring 5 and the multiple main oil seals 61 are stacked sequentially from top to bottom. The top surface of the gas ring 5 abuts against the top wall of the annular cavity (i.e., the bottom surface of the convex ring 42), and the bottommost main oil seal 61 abuts against the bottom of the annular cavity (i.e., the top surface of the oil seal pressure ring 43, or the limiting ring 432 on the top surface of the oil seal pressure ring 43).

[0048] Optionally, the main oil seal 61 is a double-lip oil seal. The oil seal assembly 6 includes multiple double-lip oil seals stacked sequentially along the axial direction of the main shaft 2. The outer wall of the double-lip oil seal is interference-fitted with the sidewall of the annular cavity (i.e., the inner wall of the sealing main ring 41), and the inner lip of the double-lip oil seal contacts the outer wall of the main shaft 2. The material of the double-lip oil seal can be polytetrafluoroethylene (PTFE). The use of double-lip sealing significantly improves airtightness compared to ordinary oil seals, and the use of PTFE material provides better wear resistance, ensuring stable pressure in the sealed chamber. The interference fit between the main oil seal 61 and the sealing main ring 41 effectively compensates for pressure loss caused by vibration, ensuring sealing performance.

[0049] It is important to note that the radial runout tolerance of the air seal installation area should not exceed 0.5mm, and the axial movement should not exceed 2mm. The shaft seal gas regulating pressure needs to be set within a certain range to ensure a positive pressure environment and guarantee the effect of preventing material from entering.

[0050] Alternatively, a bearing oil seal 9 is provided between the top of the bearing housing 7 and the outer wall of the spindle 2. The bearing oil seal 9 is located above the bearing 8, and this bearing oil seal 9 can prevent lubricating oil leakage at the bearing 8. The bearing oil seal 9 can be configured according to... Figure 1 The diagram shows a single-lip oil seal, with the inner lip of the single-lip oil seal contacting the outer wall of the spindle 2. The bearing oil seal 9 can also be made of polytetrafluoroethylene (PTFE), which offers better wear resistance.

[0051] Further optional, refer to Figure 4 An oil inlet channel 714 is also provided in the bearing housing 7. The oil inlet channel 714 can communicate with the bearing 8 and the bearing oil seal 9 to introduce grease into the bearing 8 and the bearing oil seal 9 for lubrication and to ensure the lubrication effect.

[0052] Alternatively, to facilitate the machining and installation of the bearing housing 7, refer to Figure 1 and Figure 3The bearing housing 7 includes an upper housing 71 and a lower cover 72 connected vertically. The lower end of the upper housing 71 is an open end and its top surface has a mounting hole 711. The upper housing 71 is sleeved on the bottom end of the spindle 2. There is a gap between the mounting hole 711 and the outer wall of the spindle 2 to facilitate the smooth rotation of the spindle 2. The lower cover 72 covers the bottom end of the spindle 2. The bearing 8 is sandwiched between the inner cavity of the upper housing 71 and the spindle 2. An upper stepped hole 712 with an increased diameter is formed on the top of the mounting hole 711, which connects to the top surface of the upper housing 71. The bearing oil seal 9 is installed in the upper stepped hole 712. An outer ring 73 is provided on the outer wall of the upper housing 71. The outer ring 73 is connected to the sealing seat 4.

[0053] The diameter of the mounting hole 711 is smaller than the diameter of the inner cavity of the upper housing 71. The upper outer ring of the bearing 8 rests against the bottom surface of the upper housing 71, and its lower outer ring abuts against the lower cover 72, or against the intermediate sleeve 74 on the lower cover 72. The lower cover 72 and the bottom end of the upper housing 71 can be fastened together with fasteners. Specifically, the outer ring 73 can abut against the bottom surface of the lower ring plate 443 and be fastened to the lower ring plate 443 with fasteners. The oil inlet channel 714 is provided inside the upper housing 71. The bearing 8 mentioned above can be, for example, a self-aligning roller bearing 8.

[0054] Further optional reference Figure 3 A stepped lower hole 713 with an increased diameter is formed at the bottom of the mounting hole 711, connecting to the top surface of the upper seat cylinder 71. The rollers of the bearing 8 can be aligned with the stepped lower hole 713. The step lower hole 713 facilitates the entry of lubricating grease injected through the oil inlet channel 714 into the bearing oil seal 9 after passing through the bearing 8, ensuring lubrication of the bearing oil seal 9.

[0055] Furthermore, the bottom shaft sealing device of the mixer has been improved in terms of shaft sealing structure. It utilizes gas to create a positive pressure environment at the shaft end, preventing material from entering the sealing cavity, thus achieving a non-contact seal. Additionally, the blocking effect of the retaining ring 3 and the sealing effect of the oil seal assembly 6 effectively prevent material leakage from the shaft seal. The actual installation process is as follows: (1) After installing the retaining ring 3 on the main shaft 2 and the flange plate 12 under the base plate 1, install the sealing seat 4 onto the flange plate 12. Before installing the sealing seat 4, as follows... Figure 5 As shown, after installation... Figure 6 As shown.

[0056] (2) Install the air ring 5. After the air ring 5 is installed, as follows: Figure 7 As shown.

[0057] (3) Install multiple double-lip oil seals one by one into the annular cavity. During the installation process, use tools to tap slowly, and do not deform or damage the sealing surface of the oil seal during the installation process.

[0058] (4) After the oil seal assembly 6 is installed, install the oil seal pressure ring 43. After the oil seal pressure ring 43 is installed, install the backflush elbow (i.e., air pipe connector 412) and the one-way port (i.e., one-way valve). After the oil seal assembly 6, oil seal pressure ring 43 and air pipe connector 412 are installed, as follows: Figure 8 As shown.

[0059] (5) First, install the bearing housing 7 on the workbench according to the drawings. Then, install the bearing housing 7 onto the sealing seat 4 as a whole and tighten it with bolts. Before assembling the bearing housing 7 and installing it onto the sealing seat 4, as shown in the drawings... Figure 9 As shown, after installation into sealing seat 4, as Figure 10 As shown.

[0060] During installation and operation, the following should be noted: Provide a dry air source for sealing, and ensure the air pressure of each device is adjustable; adjust the air pressure to 0.2 MPa before use; ventilate the airtight device before starting the equipment. Later, seal maintenance is required: lubricate the oil seal regularly every 6 months; regularly inspect the seal wear condition every 1 year.

[0061] Furthermore, this application also provides a conical mixer including the aforementioned mixer bottom shaft seal device. This conical mixer, having the aforementioned mixer bottom bearing device, can reduce the problem of material leakage at the bottom shaft seal of the conical mixer.

[0062] The above are merely illustrative embodiments of the present invention and are not intended to limit the scope of the invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the present invention should fall within the scope of protection of the present invention.

Claims

1. A bottom shaft sealing device for a mixer, characterized in that, include: The horizontally positioned base plate has openings; A vertically arranged main shaft, the bottom of which can rotatably pass through the opening, is fitted with a retaining ring on the main shaft and above the base plate; An annular sealing seat is installed below the base plate and sleeved on the bottom of the main shaft. A portion of the sealing seat can be inserted into the opening and can form an annular cavity with the outer wall of the main shaft. An upper annular gap is formed between the upper inner wall of the portion and the outer wall of the main shaft, and the upper annular gap is connected to the annular cavity. A retaining ring is located directly above the portion and forms a top gap with the top surface of the portion. An air ring and an oil seal assembly are arranged vertically within the annular cavity. An airflow channel is provided within the air ring, and an air inlet channel is also provided within the sealing seat. The airflow channel is connected to the upper annular gap and the air inlet channel. A bearing housing is fitted onto the lower end of the main shaft and connected to the bottom of the sealing seat. A bearing is installed between the bearing housing and the main shaft.

2. The mixer bottom shaft sealing device as described in claim 1, characterized in that, The outer periphery of the retaining ring forms a downwardly extending extension ring, and the top inner side of the partial structure has a convex ring that protrudes upward from the top surface of the base plate. The inner wall of the convex ring and the outer wall of the main shaft form the upper annular gap, and the top surface of the convex ring and the bottom surface of the retaining ring form the top gap. The lower spacer of the extension ring is disposed around the outer periphery of the convex ring and has a gap with the portion of the partial structure located around the outer periphery of the convex ring.

3. The mixer bottom shaft sealing device as described in claim 2, characterized in that, The sealing seat includes a sealing main ring, the convex ring, an oil seal pressure ring, and a connecting ring frame. The upper outer diameter of the sealing main ring matches the diameter of the opening. The upper part of the sealing main ring is inserted into the opening, and the top surface of the sealing main ring is flush with the top surface of the base plate. The convex ring is connected to the inner top of the sealing main ring and protrudes upward from the top surface of the sealing main ring. The oil seal pressure ring is sealed and connected to the bottom of the sealing main ring. The bottom surface of the convex ring, the inner wall of the sealing main ring, the top surface of the oil seal pressure ring and the outer wall of the main shaft form the annular cavity. The sealing main ring, the convex ring, and the oil seal pressure ring constitute the aforementioned partial structure, and the air intake channel is opened inside the sealing main ring; the connecting ring frame is sleeved and connected to the lower outer side of the sealing main ring, and can be connected to the base plate and the bearing seat respectively.

4. The mixer bottom shaft sealing device as described in claim 1, characterized in that, The upper part of the structure is made of stainless steel.

5. The mixer bottom shaft sealing device as described in claim 1, characterized in that, An outer ring groove and an inner ring groove are respectively provided on the outer and inner side walls of the air ring. Multiple radial holes are provided at intervals along the axial direction inside the air ring. The radial holes are connected to the outer ring groove and the inner ring groove. The outer ring groove, the inner ring groove and each of the radial holes constitute the airflow channel. One end of the air intake channel is connected to the outer ring groove, and the other end of the air intake channel is connected to an air pipe connector.

6. The mixer bottom shaft sealing device as described in claim 1, characterized in that, The oil seal assembly includes a plurality of double-lip oil seals stacked sequentially along the axial direction of the main shaft. The outer wall of the double-lip oil seal is interference-fitted with the sidewall of the annular cavity, and the inner lip of the double-lip oil seal is in contact with the outer wall of the main shaft.

7. The mixer bottom shaft sealing device as described in claim 1, characterized in that, A bearing oil seal is provided between the top of the bearing housing and the outer wall of the spindle, and the bearing oil seal is located above the bearing.

8. The mixer bottom shaft sealing device as described in claim 7, characterized in that, The bearing housing is also provided with an oil inlet channel, which can communicate with the bearing and the bearing oil seal.

9. The mixer bottom shaft sealing device as described in claim 7, characterized in that, The bearing housing includes an upper housing cylinder and a lower cover connected vertically. The lower end of the upper housing cylinder is an open end and its top surface is provided with a mounting hole. The upper housing cylinder is sleeved on the bottom end of the spindle, and there is a gap between the mounting hole and the outer wall of the spindle. The lower cover is installed at the bottom end of the main shaft, the bearing is sandwiched between the inner cavity of the upper seat cylinder and the main shaft, and an upper stepped hole with an increased diameter is formed at the top of the mounting hole, which connects to the top surface of the upper seat cylinder. The bearing oil seal is installed in the upper stepped hole. An outer ring is provided on the outer wall of the upper seat cylinder, and the outer ring is connected to the sealing seat.

10. A conical mixer, characterized in that, Includes the mixer bottom shaft seal device as described in any one of claims 1-9.

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