Shaft seal mechanism and replacement mechanism thereof

Abstract

To provide a shaft seal mechanism and its replacement mechanism easy in replacement, while preventing abrasion of a rotary shaft.SOLUTION: When the rotating shaft 20 of the rotation generating mechanism 10 is rotated, the stirring blade 22 at the tip of the rotating shaft 20 rotates in the tank 30, and the contents in the tank 30 are stirred. The shaft seal mechanism 100 slides on the surface of the oil seal 160 between the rotating shaft side fixing part 150 and the tank side fixing part 110, and sealing of the inside of the tank with respect to the rotating shaft 20 is performed by the oil seal 160 outside the seal ring 116, so that abrasion does not occur in the rotating shaft 20. The abrasion powder and the foreign matter generated in the portion of the oil seal 160 are directed from the upper surface of the seal ring 116 toward the fixing plate 114 and the stirring seat 112, and are prevented from being mixed into the tank 30.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a seal mechanism for a rotating shaft and a replacement mechanism thereof, and more particularly to an improvement in a seal mechanism and a replacement mechanism thereof suitable for an agitator that agitates raw materials in a tank. [Background technology]

[0002] An example of a "conventional seal mechanism" is the "seal mechanism for a rotating shaft" described in Patent Document 1 below. This is a seal mechanism for a rotating shaft in a fluid transfer device such as a gear pump, and is intended to economically address and deal with wear on the rotating shaft. The seal mechanism for a rotating shaft is made up of a sleeve fitted onto the rotating shaft, a seal ring whose outer periphery is fitted into a hole in a casing through which the rotating shaft passes and whose inner periphery is in sliding contact with the outer periphery of the sleeve, and a fixing means for detachably fastening the sleeve to the rotating shaft, so that the sleeve bears the wear of the seal ring, and the rotating shaft is isolated from this wear, thereby improving economy.

[0003] The "sealing device for a rotating shaft" in Patent Document 2 listed below is designed to prevent wear on the rotating shaft by providing a cylindrical portion on the outer periphery of the rotating shaft and having an oil seal come into contact with the outer periphery of this cylindrical portion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-324941 [Patent Document 2] Japanese Patent Application Publication No. 58-37373 Summary of the Invention [Problem to be solved by the invention]

[0005] While the above-mentioned background art technologies all have in common the aim of preventing wear on the rotating shaft, the seal provided on the outer periphery of the shaft wears out. This can lead to the risk of wear debris and foreign matter generated by the lubricating oil and friction on the rotating shaft entering the tank. Furthermore, the worn seal needs to be replaced, but if there is a heavy object such as a reducer on the shaft, heavy machinery is required, which is labor-intensive and costly.

[0006] The present invention focuses on this point and aims to provide a shaft seal mechanism and its replacement mechanism that maintains the airtightness of the tank, prevents wear of the rotating shaft and the resulting intrusion of foreign matter into the tank, and is easy to replace. [Means for solving the problem]

[0007] The shaft sealing mechanism of the present invention is a shaft sealing mechanism for a rotating shaft of an agitation mechanism for agitating contents in a container, and is provided on the outside of the rotating shaft of the agitation mechanism, and is equipped with a seal ring fixed to the container side, a seal case fixed to the rotating shaft side, and an oil seal provided between the seal ring and the seal case, and is characterized in that the oil seal seals the rotating shaft.

[0008] The oil seal is not attached directly to the rotating shaft, which prevents wear on the rotating shaft. In addition, the seal ring has a smaller diameter than the seal case, and the oil seal is located between the inside of the seal case and the outside of the seal ring, which reduces the amount of wear powder and foreign matter generated in the seal area that gets mixed into the housing.

[0009] The shaft seal replacement mechanism of the present invention is characterized in that the rotating shaft is divided into an upper shaft and a lower shaft, which are connected by a split coupling, the shaft seal mechanism is attached to the lower shaft side, and when replacing the shaft seal mechanism, the split coupling is removed and a gap is formed between the upper and lower shafts, and the shaft seal mechanism is replaced through this gap. The above and other objects, features, and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings. [Effects of the Invention]

[0010] According to the present invention, a seal ring is provided on the outside of the rotating shaft of the stirring means and fixed to the housing side, a seal case is fixed to the rotating shaft side, a seal that slides between the seal ring and the seal case is provided, and the rotating shaft is divided, so that the shaft seal can be easily replaced while preventing wear on the rotating shaft and the resulting foreign matter from entering the housing. [Brief explanation of the drawings]

[0011] [Figure 1] Example 1 shows an example in which the present invention is applied to agitating the contents of a tank, which is a container. [Figure 2] 1 shows the shaft sealing mechanism in the embodiment, where (A) shows the entire cross section and (B) shows an exploded cross section. [Figure 3] 1 shows how the shaft seal mechanism is assembled. [Figure 4] 1 shows a shaft seal replacement mechanism according to a second embodiment of the present invention, where (A) shows the entire mechanism and (B) shows the main part. [Figure 5] The procedure for replacing the shaft seal using the shaft seal replacement mechanism will be described below. DETAILED DESCRIPTION OF THE INVENTION

[0012] The best mode for carrying out the present invention will be described in detail below with reference to examples. [Example]

[0013] FIG. 1 shows one embodiment of the present invention. This figure shows an example in which the present invention is applied to agitating the contents of a tank, which is a container. A rotation generating mechanism 10 is disposed on top of an agitator stand 12, and a rotating shaft (main shaft) 20 extends from the agitator stand 12 into the tank 30. An agitator blade 22 is provided at the tip of the rotating shaft 20, and the contents in the tank 30 are agitated by the rotation of the agitator blade 22. Note that agitator blades 22 of various shapes are known, and are not limited to the one shown in the figure. In this embodiment, a shaft sealing mechanism 100 and a shaft seal replacement mechanism 200 are provided between the rotation generating mechanism 10 and the tank 30. Of these, the shaft sealing mechanism 100 will be described as Example 1.

[0014] FIG. 2(A) shows an overall cross section of the shaft seal mechanism 100, FIG. 2(B) shows exploded cross sections of each part, and FIG. 3 shows the assembly state. In these figures, the shaft seal mechanism 100 is configured with an oil seal 160 provided between a tank-side fixed part 110 and a rotating-shaft-side fixed part 150. The tank-side fixed part 110 is assembled by stacking an agitator seat 112, a fixing plate 114, and a seal ring 116 in order from the tank side. On the other hand, the rotating-shaft-side fixed part 150 is assembled by stacking a seal case 152 and a remover disk 154 in order from the rotation generating mechanism side. An oil seal 160, which is a sealing mechanism that seals the rotating shaft, is provided between the seal ring 116 and the seal case 152. That is, the oil seal 160 is in sliding contact with the seal ring 116 and the seal case 152. The individual parts are described in detail below.

[0015] a. Agitator seat 112: This is an agitator mounting part that is welded to the tank side and is a flange-shaped part for connecting the tank 30 to the upper parts, and the main parts of the shaft sealing mechanism 100 and the rotation generating mechanism 10 are placed on this agitator seat 112. This makes it possible to attach the shaft sealing mechanism 100 to the tank 30 regardless of the shape or dimensions of the tank side. Attachment to the tank 30 is mainly performed by welding. An O-ring groove 112B is formed on the upper surface of the agitator seat 112. Also, a shaft hole 112R is formed in the center, through which the rotating shaft 20 passes. The rotating shaft 20 can rotate without coming into contact with the surface of the shaft hole 112R.

[0016] b. Fixing plate 114: This is provided between the stirring seat 112 and the seal ring 116, and is used to adjust the joint between them. It is attached to the stirring seat 112 with screws 114A. An O-ring groove 114B is formed on the top surface. A shaft hole 114R through which the rotating shaft 20 passes is also formed in the center. The rotating shaft 20 can rotate without coming into contact with the surface of the shaft hole 114R. The stirring seat 112 and fixing plate 114 may be integrally configured.

[0017] c. Seal ring 116: A cylindrical portion 116A is formed in the center, through which the rotating shaft 20 passes. The outer surface of the cylindrical portion 116A is precisely machined to form a sealing surface 116B to which the oil seal 160 is attached. This sealing surface 116B is coated with chromium nitride or the like, providing high durability against wear caused by the sliding of the oil seal 160 and high corrosion resistance against acids and alkalis. The seal ring 116 is fixed to the fixing plate 114 by attaching screws 116C to mounting holes 116E and 114E. The mounting hole 116E is, for example, approximately 20% larger than the generally specified or recommended hole diameter for the screw 116C. This increases the degree of freedom during installation and allows the structure to easily accommodate and correct any displacement in the position relative to the rotating shaft 20 that may occur due to manufacturing precision, years of use, and other factors related to the agitation drive. For mounting holes 116E with larger diameters, a flat washer (not shown) can be used to ensure reliable fastening of screws 116C.

[0018] d, Seal case 152: This is a part that holds the oil seal 160 and is attached to the rotating shaft 20. It is attached to the rotating shaft 20 with screws 152A in a direction perpendicular to the axial direction of the rotating shaft 20. The attachment height (position in the direction of the rotating shaft 20) can be set as desired, so the attachment position can be changed to suit the condition of the sliding surface of the oil seal 160. The lower end of the seal case 152 in the figure is expanded in diameter to form a cylindrical case portion. In addition, an O-ring groove 152C is formed inside the shaft hole 152R of the seal case 152, and an O-ring 152D is attached to it.

[0019] e. Remover disc 154: This is a built-in special tool that is inserted into the seal case 152 beforehand when installing the oil seal 160. It is used to remove the seal case 152 or the oil seal 160 without damaging them when replacing the oil seal 160. It is a disk-shaped part that is slightly smaller than the inner diameter of the cylindrical case portion of the seal case 152 described above, and has screw holes 154A on its surface so that they are located inside the oil seal 160 (so that they fit below the inner diameter). These screw holes 154A can be used to attach jack screws or slide hammer adapters, and can function to push the oil seal 160 out from the depths of the seal case 152. A shaft hole 154R is formed in the center of the remover disc 154, through which the rotating shaft 20 passes.

[0020] f. Set collar: This is a part (not shown) that is attached to the top of the seal case 152 as an auxiliary part to maintain the seal case 152 at the optimum mounting angle when there is a risk of the seal case 152 tilting due to factors such as the shaft diameter of the rotating shaft 20, the diameter of the seal surface 116B, or height restrictions on the mounting part. By deliberately separating it from the seal case 152, it is possible to choose whether or not to attach it depending on the situation.

[0021] g. Oil seal 160: This is provided between the seal surface 116B of the seal ring 116 and the inside of the cylindrical portion of the seal case 152. That is, the seal surface 116B of the seal ring 116 has a smaller diameter than the cylindrical case portion of the seal case 152, and the oil seal 160 is provided between the inside of the seal case 152 and the outside of the seal ring 116. Therefore, wear powder and foreign matter generated in the seal portion are discharged from the seal side of the seal ring 116 or the oil seal 160 to the upper surface side of the seal ring 116, as shown by arrow F in FIG. 2(A). That is, they are discharged in a direction away from the rotating shaft 20, reducing contamination into the tank 30. A commercially available oil seal can be used as the oil seal 160.

[0022] The stirring seat 112, fixing plate 114, and seal ring 116 are joined by attaching screws 114A to mounting holes 114D, 112D and screws 116C to mounting holes 116E, 114E while sealing the inside of the tank by sandwiching O-rings 112C, 114C in O-ring grooves 112B, 114B, respectively, to form the tank-side fixed part 110. The rotating shaft 20, which can rotate without contacting the surface of the rotating shaft 20, passes through the tank-side fixed part 110, and the tank-side fixed part 110 is fixed to the top of the tank. Meanwhile, the seal case 152 and the remover disk 154 are overlapped to form the rotating shaft-side fixed part 150, which is fixed to the rotating shaft 20 by screws 152A. An oil seal 160 is sandwiched between the tank-side fixed part 110 and the rotating shaft-side fixed part 150.

[0023] When the rotating shaft 20 of the rotation generating mechanism 10 is rotated with this shaft sealing mechanism 100 attached, the agitating blade 22 at the tip of the rotating shaft 20 rotates inside the tank 30, agitating the contents inside the tank 30. In this case, the rotating shaft 20 slides on the surface of the oil seal 160 between the rotating shaft side fixed part 150 and the tank side fixed part 110, and the oil seal 160 on the outside of the seal ring 116 seals the inside of the tank, preventing wear on the rotating shaft 20 as occurs with so-called gland packing. Therefore, wear and deterioration of the rotating shaft 20 are prevented.

[0024] Furthermore, since the fixing plate 114 and the stirring seat 112 have larger diameters than the oil seal 160, wear powder and foreign matter (contamination) generated in the oil seal 160 flows from the upper surface of the seal ring 116 toward the fixing plate 114 and further toward the stirring seat 112, that is, in a direction away from the rotating shaft 20. This prevents these particles from entering the tank 30.

[0025] As described above, according to this embodiment, the following effects can be obtained. a. Freedom of installation: Since the sealing surface (sliding part) required for sealing is not provided on the surface of the rotating shaft, it is possible to achieve the required sealing performance even if the surface finish and processing precision of a newly manufactured rotating shaft are not ensured, or even if the rotating shaft has deteriorated during use. b. Compact design: Installation is possible as long as there is enough space to fit the gland packing and stuffing box. c) Simple structure: Because it has a small number of parts, it is easy to manufacture and is less likely to break, and installation on equipment does not require special work that requires skill.

[0026] d) Long life and high cost performance: The main structural parts can be reused, and by replacing consumable parts (off-the-shelf products), it can be used for a long period of time. e. Safe structure: Unlike existing shaft seal devices, the sliding surface that separates pressure does not exist directly above the contents inside the tank, so wear powder from the sliding surface and foreign matter generated on the sealing surface do not get mixed into the contents. f) Procurement of parts: The main structural parts are ordinary machined parts, and consumable parts are existing products on the market, so there is no need for long manufacturing lead times of several months.

[0027] g. Rotational energy saving: Compared to existing gland packings, the sliding resistance during rotation is smaller, so driving force can be saved. h. Reduced wear and deterioration, protection of equipment: Unlike existing gland packings, it does not cause wear on the rotating shaft, so there is no wear or deterioration of the rotating shaft. i. High maintainability: The built-in remover disc makes it easy to remove the oil seal, which is a consumable part, putting less strain on the mechanism and allowing for reliable maintenance. [Example]

[0028] Next, a shaft seal replacement mechanism 200 of a second embodiment will be described with reference to Figures 4 and 5. Figure 4(A) shows the entire shaft seal replacement mechanism 200, and Figure 4(B) shows the main parts. In these figures, the rotating shaft 20 described above is divided into an upper shaft 20A and a lower shaft 20B, and the upper shaft 20A is capable of moving up and down together with the stirring stand 12. The lower shaft 20B is provided with the above-mentioned shaft seal mechanism 100. The upper shaft 20A and the lower shaft 20B are connected by a split coupling 210. The individual parts will be described in detail as follows.

[0029] a. Mixing stand 12: For new products, a manufactured product with the necessary dimensions will be used, but for existing tank equipment, it can be used as is by using the stand spacer described below as necessary. As a mechanism for replacing the shaft seal, the mixing stand 12 itself is equipped with a jack bolt mechanism (not shown) that allows it to move upward independently.

[0030] b, Stand spacer (not shown): A spacer for raising the height of the agitation stand 12. As described above, the shaft sealing mechanism 100 is provided at the bottom of the agitation stand 12, and therefore, except in cases where it is specially designed, the stand spacer is inserted as appropriate so that only the shaft sealing part can be replaced, thereby ensuring installation space for the shaft sealing mechanism 100.

[0031] c) Upper shaft 20A: A rotation generating mechanism 10 such as an electric motor or a reducer is provided on the upper side, and a groove 220A is provided at the lower end of the shaft for attaching a split coupling 210. In addition, a fall prevention function is provided within the bearing mechanism on the upper part of the stirring stand 12, so that the upper shaft 20A can always maintain its positional relationship (not shown).

[0032] d, Lower shaft 20B: A groove 220B is provided at the top end of the shaft for attaching the split coupling 210, and the middle of the shaft is shaped to limit downward movement of the shaft during maintenance. The shape of this part is designed to minimize sudden changes in shape, such as increasing the shaft diameter towards the top, taking into account stress caused by mixing imbalance.

[0033] e. Split coupling 210: Comprised of 210A and 210B, this is a component that connects the upper shaft 20A and the lower shaft 20B. It is a common component that is also available as a ready-made product. The inner circumference of the coupling is provided with grooves 210C that fit into the grooves 220A of the upper shaft 20A and the grooves 220B of the lower shaft 20B, preventing them from falling off. A key (not shown) is also provided to prevent idling.

[0034] Next, the operation of the shaft seal replacement mechanism 200 will be described with reference to Figure 5. The upper shaft 20A and lower shaft 20B are coupled by the split coupling 210 as shown in Figure 5(A). When replacing the shaft seal, as shown in Figure 5(B), the seal case 152 is moved upward along the rotating shaft 20 to lift it up. Furthermore, as shown in Figure 5(C), the seal ring 116 and the stirring stand 12 are pulled upward, and a fall prevention jig 230 is attached between the seal ring 116 and the fixing plate 114. The fall prevention jig 230 is a flat bar-shaped structure set on both sides to sandwich the rotating shaft 20, and is provided so that the lower shaft 20B can be supported by the fixing plate 114.

[0035] Next, as shown in FIG. 1(D), the split couplings 210A and 210B are removed from the rotating shaft 20, and the rotating shaft 20 is separated into the upper shaft 20A and the lower shaft 20B. Then, as shown in FIG. 1(E), the upper shaft 20A is moved upward together with the stirring stand 12 to ensure the space necessary for replacing the shaft seal. In this state, the seal case 152, its inner remover disc 154, oil seal 160, and seal ring 116 are removed from the lower shaft 20B and replaced with new ones. Next, the above-mentioned work is carried out in reverse order to complete the replacement of the shaft seal mechanism 100.

[0036] In the past, when replacing the shaft seal, the entire drive mechanism located above had to be disassembled at the same time, resulting in significant costs and labor. This meant that the shaft seal mechanism used had to be a more expensive, high-performance one, in case of a malfunction. In contrast, in this embodiment, the shaft seal mechanism 100 can be removed and replaced without disassembling the upper rotation generating mechanism 10 or the agitator stand 12, reducing the scale of the replacement work and the burden.

[0037] As described above, according to this embodiment, the following effects can be obtained. a) The rotating shaft 20 is divided into upper and lower halves, and a space is provided between them to perform the shaft sealing mechanism 100 replacement work, so that the replacement work can be performed independently without disassembling the rotation generating mechanism 10 or the stirring stand 12. b. It is only necessary to divide the rotating shaft 20, and the top part is provided with a rotation generating mechanism 10 such as a motor and a reducer, and underneath that is a stirring stand 12 equipped with a bearing mechanism, and the lower part of this stirring stand 12 has a shaft sealing mechanism 100, so the configuration is the same and does not deviate significantly from the existing structure. c. The rotating shaft 20 can be manually raised by a jack bolt (not shown) attached to the stirring stand 12 itself.

[0038] Other Embodiments The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit and scope of the present invention. For example, the following modifications are also included. (1) In the above embodiment, the shaft seal replacement mechanism 200 of Example 2 is applied to the shaft seal mechanism 100 of Example 1, but it is also possible to use only the shaft seal mechanism 100, or only the shaft seal replacement mechanism 200. However, considering that the shaft seal mechanism 100 is inferior to expensive mechanical seals made of ceramic or carbon materials, particularly in terms of durability, by combining it with the shaft seal replacement mechanism 200, the advantage of being able to easily replace parts can be utilized more effectively, and the weakness in terms of durability can be compensated for. (2) The shapes and dimensions shown in the above embodiments are merely examples and may be modified as necessary. (3) The tank can accommodate a variety of materials, including liquids and powders. [Industrial Applicability]

[0039] According to the present invention, a seal ring is provided on the outside of the rotating shaft of the stirring means and fixed to the container side, a seal case is fixed to the rotating shaft side, a seal that slides between the seal ring and the seal case is provided, and the rotating shaft is divided.This prevents wear on the rotating shaft and the resulting foreign matter from entering the container, while making it easy to replace the shaft seal, making the device suitable for stirring devices for contents in a container. [Explanation of symbols]

[0040] 10: Rotation generating mechanism 12: Mixing stand 20: Rotation axis (main axis) 20A: Upper shaft 20B: Lower shaft 22: Stirring blade 30: Tank 100: Shaft seal mechanism 110: Tank side fixing part 112: Stirring seat 112B, 114B: O-ring groove 112C, 114C: O-ring 112R: Shaft hole 114: Fixing plate 114A, 116C: Screws 114D, 112D: Mounting holes 114R: Shaft hole 116: Seal ring 116A: Cylindrical part 116B: Seal surface (sliding surface) 116C:Screw 116E, 114E: Mounting holes 150: Rotating shaft side fixing part 152: Seal case 152A:Screw 152C: O-ring groove 152D: O-ring 152R: Shaft hole 154: Remover disk 154A: screw hole 154R: Shaft hole 160: Oil seal 200: Shaft seal replacement mechanism 210, 210A, 210B: Split coupling 210C: Grooving 220A, 220B: Grooving 230: Fall prevention jig

Claims

1. A shaft sealing mechanism for a rotating shaft of an agitation mechanism for agitating contents in a container, a seal ring provided on the outer side of the rotation shaft of the stirring mechanism and fixed to the container side; a seal case fixed to the rotary shaft side; an oil seal provided between the seal ring and the seal case; It is equipped with The shaft seal mechanism is characterized in that the oil seal seals the rotating shaft.

2. 2. The shaft seal mechanism according to claim 1, wherein a coating is applied to a seal surface of said seal ring that comes into contact with said oil seal, said coating providing durability and corrosion resistance against wear caused by sliding of the oil seal.

3. The seal ring has a smaller diameter than the seal case, 2. The shaft seal mechanism according to claim 1, wherein the oil seal is provided between the inside of the seal case and the outside of the seal ring.

4. 2. The shaft seal mechanism according to claim 1, wherein the seal case has a built-in remover disk for removing the oil seal when replacing it.

5. A shaft seal replacement mechanism for replacing the shaft seal mechanism according to any one of claims 1 to 4, The rotating shaft is divided into an upper shaft and a lower shaft, which are joined together by a split coupling, and the shaft sealing mechanism is attached to the lower shaft side. When replacing the seal, the split coupling is removed, a gap is formed between the upper shaft and the lower shaft, and the seal mechanism is replaced through this gap.

6. 6. The shaft seal replacement mechanism according to claim 5, wherein an agitation stand is provided between the container and the rotation generating mechanism, and the upper shaft is movable up and down together with the agitation stand.

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