Shaft end seal for feeding device of batch mixer

Abstract

The utility model relates to a shaft end seal for a feeding device of a batch mixer, the batch mixer comprises a feeding pipe and a drum body, the drum body is coaxially arranged on the outer side of the feeding pipe, the drum body rotates around the feeding pipe, the shaft end seal comprises an end cover and a cavity, the end cover is fixed on the drum body, and the cavity is arranged in the cavity. The cavity is fixed to the feeding pipe and located at the tail end of the end cover. At least one carbon ring sealing structure is fixed on the inner side of the end cover, the carbon ring sealing structure comprises a plurality of carbon ring pieces and a tension spring, and all the carbon ring pieces are sequentially arranged on the outer side of the feeding pipe in an abutting mode and are hooped through the tension spring. According to the shaft end seal, the lip seal unit supported by the metal framework in the radial direction is adopted for sealing in the radial direction, the carbon ring sealing structure is adopted in the axial direction, the sealing performance of powder in the batch mixer is better, meanwhile, the consumption of isolation gas N2 is lower, the reliability of the whole set of seal is higher, and the service life is longer.

Description

Technical Field

[0001] The utility model relates to the technical field of mechanical seals, in particular to a shaft end seal for a feeding device of a batch mixer. Background Art

[0002] The batch mixer is a kind of equipment used for mixing, stirring, breaking up, dispersing and other processing techniques. It is widely used in chemical, pharmaceutical, food, metallurgy, building materials and other industries. Its main principle is to drive the agitator to rotate through the motor to mix or stir the materials in the container. When working, the outer drum of the batch mixer rotates, and the end feed pipe and the middle part of the equipment connected to the feed pipe are stationary. However, due to the large size of the batch mixer, the sealing part is a dynamic seal, which rotates at the outer diameter and is stationary at the inner diameter, which is different from the conventional dynamic seal. In addition, the axial space of the equipment is very compact, which poses another challenge to the design of the shaft end seal. Utility Model Content

[0003] The purpose of the utility model is to overcome the defects of the prior art and provide a shaft end seal for a batch mixer feeding device.

[0004] In order to achieve the purpose of the utility model, the present application provides the following technical solutions.

[0005] In the first aspect, the present application provides an axial end seal for a feeding device of a batch mixer, the batch mixer comprising a feeding pipe and a drum body, the drum body being coaxially arranged on the outside of the feeding pipe, and the drum body rotating around the feeding pipe, the axial end seal comprising an end cover and a cavity, the end cover being fixed on the drum body, the cavity being fixed on the feeding pipe, and the cavity being located at the rear end of the end cover; at least one carbon ring sealing structure is fixed on the inner side of the end cover, the carbon ring sealing structure comprising a multi-petal carbon ring sheet and a tension spring, all of the carbon ring sheets being sequentially abutted against the outside of the feeding pipe, and all of the carbon ring sheets are clamped by the tension spring.

[0006] In one embodiment of the first aspect, the carbon ring sealing structure includes a carbon ring seat, the carbon ring seat is fixed to the end cover by a first anti-rotation pin, at least one mounting groove is provided on the inner side of the carbon ring seat, the carbon ring sheet is installed in the mounting groove, and the carbon ring sheet and the carbon ring seat are fixed by a second anti-rotation pin.

[0007] In one implementation of the first aspect, the shaft end seal comprises 2 to 4 carbon ring sealing structures, each carbon ring sealing structure comprises 2 to 6 carbon ring pieces, and the inner edges of all the carbon ring pieces are in contact with the outer wall of the feed pipe.

[0008] In one implementation of the first aspect, the side surface of the feed pipe in contact with the carbon ring sheet is subjected to wear-resistant treatment.

[0009] In one implementation of the first aspect, a first O-ring is provided between the carbon ring seat and the drum body, and a second O-ring is provided between the end cover and the drum body.

[0010] In an implementation of the first aspect, a plurality of lip seal units distributed radially along the cavity are fixed to the cavity, and a front end of the lip seal unit abuts against a rear end side surface of the end cover.

[0011] In one embodiment of the first aspect, each of the lip seal units includes a metal frame and a filler, the metal frame is a hollow structure with an open front end, the filler is interference fitted in the hollow structure of the metal frame, and the front end of the filler abuts against the rear end side of the end cover.

[0012] In one implementation of the first aspect, the filler is made of polytetrafluoroethylene, and the polytetrafluoroethylene is mixed with graphite or molybdenum disulfide.

[0013] In an implementation of the first aspect, a step is provided on the front end side of the cavity, a pressure plate is fixed to the outer side of the cavity by a set screw, and the lip seal unit is fixed to the cavity by squeezing the step and the pressure plate.

[0014] In an embodiment of the first aspect, the side surface of the end cover in contact with the lip seal unit is subjected to wear-resistance treatment.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] The shaft end seal of the present application adopts a radial lip seal unit with a metal skeleton support for sealing in the radial direction and a carbon ring sealing structure in the axial direction, which has better sealing performance for powder in the batch mixer and lower consumption of isolation gas N2. The reliability of the whole set of seals is higher and the service life is longer. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of a partial cross-sectional structure of the shaft end seal of this application.

[0018] In the accompanying drawings, 1 is a lip seal unit, 2 is a cavity, 3 is a set screw, 4 is a pressure plate, 5 is a washer, 6 is a cross recessed countersunk screw, 7 is a carbon ring sheet, 8 is a tension spring, 9 is a carbon ring seat, 10 is a second anti-rotation pin, 11 is a first O-ring, 12 is a first transmission pin, 13 is a second O-ring, 14 is a screw, 15 is an end cover, 16 is a drum body, 17 is a feed pipe, 18 is a metal skeleton, and 19 is a filler. DETAILED DESCRIPTION

[0019] Unless otherwise defined, the technical terms or scientific terms used in this specification and claims shall have the ordinary meanings understood by persons with ordinary skills in the technical field to which the utility model belongs. All the values ​​from the lowest value to the highest value listed in this article refer to all the values ​​obtained by incrementing one unit between the lowest value and the highest value when the difference between the lowest value and the highest value is more than two units.

[0020] The following will describe the specific implementation of the utility model. It should be noted that in the specific description of these implementations, in order to provide a concise description, this specification cannot provide a detailed description of all the features of the actual implementation. Without departing from the spirit and scope of the utility model, those skilled in the art may modify and replace the implementation of the utility model, and the resulting implementation is also within the scope of protection of the utility model.

[0021] In view of the different working conditions of the feeding device of the batch mixer and the very compact axial space, the present application proposes an axial end sealing type of the feeding device of the batch mixer, that is, a combination structure of radial sealing and axial sealing, and nitrogen with a pressure slightly higher than that of the sealing chamber is introduced between the two as sealing gas.

[0022] The radial seal adopts a multi-channel lip seal unit with a metal skeleton support. The filler in the lip seal unit is made of polytetrafluoroethylene filled with graphite or molybdenum disulfide to enhance the lubricity and wear resistance of the sealing surface. The lip seal unit is installed with interference fit, and the sealing performance is good. At the same time, in order to increase the wear resistance of the lip seal, the surface of the end cover needs to be specially treated for wear resistance, such as spraying wear-resistant alloys. The introduction of nitrogen gas with a slightly higher pressure will more effectively block the trace powder that may leak from the lip seal.

[0023] The axial seal adopts two sequentially arranged split-petal carbon ring seals, which mainly play the role of reducing the axial leakage of nitrogen. The sealing carbon ring adopts a split-petal structure, and the outer diameter is tightened circumferentially by a tension spring to form a whole. The sealing carbon ring is equipped with an anti-rotation mechanism, so that the carbon ring can only float radially and cannot rotate. At the same time, in order to enhance the wear resistance of the sealing carbon ring, the surface of the matching feed pipe needs to be specially treated for wear resistance, such as spraying wear-resistant alloy.

[0024] Example

[0025] The following is a detailed description of an embodiment of the present invention. This embodiment is implemented based on the technical solution of the present invention, and a detailed implementation method and a specific operation process are given, but the protection scope of the present invention is not limited to the following embodiment.

[0026] Example 1

[0027] A shaft end seal for a batch mixer feeding device, the structure of which is as follows Figure 1 As shown, Figure 1 This is half of the entire cross-sectional structure diagram. Due to the symmetry between the upper and lower parts, only the upper part of the structure is shown.

[0028] The batch mixer includes a feed pipe 17 and a drum body 16. The drum body 16 is coaxially arranged outside the feed pipe 17 and rotates around the feed pipe 17. The end cover 15 is fixed to the drum body 16 by screws 14. Therefore, the end cover 15 rotates with the drum body 16. The cavity 2 is fixed to the feed pipe 17 by cross recessed countersunk screws 6. The cavity 2 is located at the rear end of the end cover 15.

[0029] A carbon ring seat 9 is provided at the front center of the end cover 15, and the carbon ring seat 9 is fixed to the end cover 15 by a first anti-rotation pin 12. At least two mounting grooves are provided inside the carbon ring seat 9, and a carbon ring is installed in each mounting groove. Each carbon ring includes a three-petal carbon ring sheet 7, and the inner edge of the carbon ring sheet 7 is in contact with the outer wall of the feed pipe 17, and the side of the feed pipe 17 in contact with the carbon ring sheet 7 is sprayed with a wear-resistant alloy; the outer edge of the carbon ring sheet 7 is clamped by a tension spring 8, and the carbon ring sheet 7 is fixed to the carbon ring seat 9 by a second anti-rotation pin 10. A first O-ring 11 is provided between the carbon ring seat 9 and the drum body 16, and a second O-ring 13 is provided between the end cover 15 and the drum body 16.

[0030] A step is provided on the front side of the cavity 2, a pressure plate 4 is fixed on the outside of the cavity 2 by a set screw 3, three lip seal units 1 are installed between the step and the pressure plate 4, and the lip seal unit 1 includes a metal skeleton 18, the metal skeleton 18 is a hollow structure with an open front end, and a tetrafluoro filler 19 is filled in the hollow structure of the metal skeleton 18. The material of the tetrafluoro filler 19 is polytetrafluoroethylene filled with graphite, and the front end of the filler 19 abuts against the rear end side of the end cover 15. The side of the end cover 15 that contacts the lip seal unit 1 is sprayed with a wear-resistant alloy.

[0031] There are several sealing structures in the above structure, which are as follows:

[0032] 1. Radial seal: The three lip seal units 1 are interference-mounted on the cavity 2 in sequence. The pressure plate 4 is fixed on the cavity 2 by the set screws 3, which plays the role of limiting the lip seal unit 1. The cavity 2 is installed on the feed pipe 17 at the end of the equipment by the cross recessed countersunk screws 6. The gasket 5 plays the role of static sealing. The above are the stationary parts of the seal.

[0033] 2. Axial sealing: The tension spring 8 tightens the split carbon ring piece 7, and is installed on the carbon ring seat 9 through the second anti-rotation pin 10. The carbon ring seat 9 is then installed on the end cover 15 through the first anti-rotation pin 12 to play a transmission role. The screw 14 installs the end cover 15 on the rotating drum body 16. The first O-ring 11 and the second O-ring 13 respectively play the role of static sealing between the carbon ring seat 9, the end cover 15 and the drum body 16. The above are the sealed rotating parts.

[0034] 3. The mating place between the end cover 15 and the lip seal unit 1 is subjected to special surface treatment, such as spraying wear-resistant alloy, etc.; the mating place between the feed pipe 17 at the end of the equipment and the carbon ring sheet 7 is subjected to special surface treatment, such as spraying wear-resistant alloy, etc.

[0035] The shaft end seal type of a batch mixer feeding device proposed in the present application is a combined structure of radial seal and axial seal. In this structure, two carbon rings are tightened by tension springs 8, installed on carbon ring seats 9 and end covers 15, and rotate with the drum body 16 of the equipment to play the role of axial seal. The lip seal unit 1 is interference-mounted on the cavity 2, limited by a pressure plate 4, and then connected to the feed pipe 17 (stationary part) together with the cavity 2 to play the role of radial seal. Nitrogen with a slightly higher pressure than that of the sealing chamber is introduced between the axial seal and the radial seal as a sealing gas, and a small amount of sealing gas enters the medium side through the radial seal to prevent leakage of the medium; two carbon ring seals are arranged in sequence in the axial direction to reduce axial leakage of nitrogen.

[0036] The above description of the embodiments is to facilitate those of ordinary skill in the art to understand and apply the present application. It is obvious that those familiar with the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without having to pay creative labor. Therefore, the present application is not limited to the embodiments herein, and improvements and modifications made by those skilled in the art based on the contents disclosed in the present application without departing from the scope and spirit of the present application are within the scope of the present application.

Claims

1. A shaft end seal for a feeding device of a batch mixer, the batch mixer comprising a feeding pipe and a drum body, the drum body being coaxially arranged on the outside of the feeding pipe and the drum body rotating around the feeding pipe, characterized in that: The shaft end seal includes an end cover and a cavity, wherein the end cover is fixed on the drum body, and the cavity is fixed on the feed pipe, and the cavity is located at the tail end of the end cover; at least one carbon ring sealing structure is fixed on the inner side of the end cover, and the carbon ring sealing structure includes a multi-petal carbon ring sheet and a tension spring, and all the carbon ring sheets are sequentially abutted against the outer side of the feed pipe, and all the carbon ring sheets are clamped by the tension spring.

2. The shaft end seal for a batch mixer feeding device according to claim 1, characterized in that: The carbon ring sealing structure includes a carbon ring seat, which is fixed to the end cover via a first anti-rotation pin. The inner side of the carbon ring seat is provided with at least one mounting groove, the carbon ring sheet is mounted in the mounting groove, and the carbon ring sheet and the carbon ring seat are fixed via a second anti-rotation pin.

3. The shaft end seal for a batch mixer feeding device according to claim 1 or 2, characterized in that: The shaft end seal comprises 2 to 4 carbon ring sealing structures, each of which comprises 2 to 6 carbon ring pieces, and the inner edges of all the carbon ring pieces are in contact with the outer wall of the feed pipe.

4. The shaft end seal for a batch mixer feeding device according to claim 3, characterized in that: The side surface of the feed pipe in contact with the carbon ring sheet is subjected to wear-resistance treatment.

5. The shaft end seal for a batch mixer feeding device according to claim 2, characterized in that: A first O-ring is arranged between the carbon ring seat and the drum body, and a second O-ring is arranged between the end cover and the drum body.

6. The shaft end seal for a batch mixer feeding device according to claim 1, characterized in that: A plurality of lip seal units distributed along the radial direction of the cavity are fixed on the cavity, and the front end of the lip seal unit abuts against the rear end side surface of the end cover.

7. The shaft end seal for a batch mixer feeding device according to claim 6, characterized in that: Each of the lip seal units includes a metal frame and a filler. The metal frame is a hollow structure with an open front end. The filler is interference-fitted in the hollow structure of the metal frame, and the front end of the filler abuts against the rear end side of the end cover.

8. The shaft end seal for a batch mixer feeding device according to claim 7, characterized in that: The filler is made of polytetrafluoroethylene, and graphite or molybdenum disulfide is mixed in the polytetrafluoroethylene.

9. The shaft end seal for a batch mixer feeding device according to claim 6, characterized in that: A step is provided on the side surface of the front end of the cavity, a pressure plate is fixed to the outer side of the cavity by means of set screws, and the lip seal unit is fixed on the cavity by means of extrusion between the step and the pressure plate.

10. The shaft end seal for a batch mixer feeding device according to claim 6, characterized in that: The side surface of the end cover in contact with the lip seal unit is subjected to wear-resistance treatment.

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