Mixing Equipment

Abstract

To provide a stirring device capable of preventing a stirring blade from falling when replacing a mechanical seal.SOLUTION: Provided is a stirring device, including: a stirring member in which a stirring blade is provided on a shaft 12; a tank 2 that has an internal space capable of housing the stirring blade and storing an object to be stirred, and that has a shaft insertion part (flat surface) 23 through which the shaft 12 is inserted from an internal space to the outside; and a mechanical seal part 13 provided in the stirring member and rotatably holding the shaft 12 in a state of being fixed to the shaft insertion part 23, wherein the shaft 12 is provided with a movement regulating part 15 for regulating the movement of the stirring member in the vertical direction and further provided with a shaft support member for locking the movement regulating part 15, so that a maintenance position of a stirring member is held even in a state where a mechanical seal part 13 is separated from a shaft insertion part 23 and moved upward in a vertical direction during maintenance.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an agitation device that agitates an object to be agitated by rotating an agitating blade inside a tank. [Background technology]

[0002] For example, in chemical plants, etc., agitation devices are widely used in which a motor drives a rotating shaft to rotate and agitate a solution, a slurry liquid, powder, etc. contained inside a tank with an agitator blade attached to the rotating shaft. In such an agitation device, the motor is provided outside the tank, and the rotating shaft connected to the motor is inserted from the outside to the inside of the tank through an opening provided at the end of the tank. The agitator blade is provided on the part of the rotating shaft located inside the tank.

[0003] A mechanical seal is also arranged to cover the opening at the end of the tank, and the mechanical seal surrounds the periphery of the rotating shaft and holds the rotating shaft so that it can rotate. This mechanical seal allows the rotating shaft to rotate without wobbling and with low dust generation. In a mixing device configured in this way, the motor is driven to rotate the rotating shaft, and the mixing target in the tank is mixed by the mixing blades on the rotating shaft. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 02-117026 Summary of the Invention [Problem to be solved by the invention]

[0005] The mechanical seal is a so-called consumable item and needs to be replaced periodically. When replacing the mechanical seal, the mechanical seal is released from the tank and the grip of the rotating shaft by the mechanical seal is released. At this time, the rotating shaft becomes free, and there is a risk that the rotating shaft will fall into the tank and damage the tank, the rotating shaft, and the agitating blades, especially when the rotating shaft is inserted into the tank in the vertical direction. If the upper end of the rotating shaft is suspended to avoid this, it will be an obstacle when removing the rotating shaft from the mechanical seal, and if the entire rotating shaft is removed from the tank before removing the rotating shaft from the mechanical seal, there is a problem that it is necessary to secure a space above the tank that is large enough to remove the rotating shaft.

[0006] In view of the above problems, the present invention aims to provide an agitation device that can prevent the agitation blades from falling off when replacing the mechanical seal. [Means for solving the problem]

[0007] In order to solve the above problems, the stirring device of the present invention is a stirring device including a stirring member having a stirring blade attached to a shaft for stirring an object by rotating, a tank having an internal space capable of accommodating the stirring blade and storing the object to be stirred, and having a shaft insertion part for inserting the shaft from the internal space to the outside, and a mechanical seal part provided on the stirring member and fixed to the shaft insertion part for rotatably holding the shaft, wherein the shaft is provided with a movement restricting part for restricting vertical movement of the stirring member, and a shaft side engagement part for engaging the movement restricting part. The shaft support member further includes a movement regulating portion and an insertion portion side supported portion supported by the shaft insertion portion, and when the mechanical seal portion is separated from the shaft insertion portion and the stirring member is positioned in a maintenance position where it has moved vertically upward, the shaft support member is positioned between the movement regulating portion and the shaft insertion portion, so that the movement regulating portion abuts against the shaft side engagement portion of the shaft support member, and the insertion portion side supported portion is supported by the shaft insertion portion, thereby maintaining the stirring member in a state where it is positioned at the maintenance position.

[0008] With this stirring device, when the mechanical seal portion is removed from the shaft, the shaft support member keeps the stirring member in the maintenance position, thereby preventing the shaft and stirring blades from falling into the tank.

[0009] The movement restricting portion may be a protrusion provided on an outer circumferential surface of the shaft, and the shaft support member may abut against a lower end of the protrusion.

[0010] In this way, the movement restricting portion can be provided without reducing the strength of the shaft.

[0011] The movement restricting portion may be a recess provided on an outer circumferential surface of the shaft, and the shaft support member may be inserted into the recess.

[0012] This allows the cross-sectional area of ​​the rotation opening to be relatively small.

[0013] In addition, the shaft support member may be composed of a plurality of divided members that can be fastened to each other, and these divided members may be fastened together with the shaft therebetween to abut against the movement restricting portion.

[0014] This can prevent the shaft from falling off the shaft support member.

[0015] In addition, it is preferable that the shaft support member is separate from the tank and is removed from the tank when the mechanical seal portion is fixed to the shaft insertion portion.

[0016] This allows the stirring device to be configured with the minimum necessary components except when the mechanical seal portion is removed.

[0017] In addition, the shaft may have a first shaft held by the mechanical seal portion, a second shaft on which the stirring blade is provided, and a coupling portion connecting the first shaft and the second shaft, and the movement regulating portion may be provided on the first shaft.

[0018] This allows the shaft to be fixed without the need to bring the coupling portion outside the tank, making it even easier to remove the mechanical seal portion.

[0019] Also, it is preferable that the rotation opening has a shape whose cross-sectional area increases from the outside of the tank toward the internal space.

[0020] This makes it possible to prevent liquid from accumulating near the rotation opening. Effect of the Invention

[0021] The stirring device of the present invention can prevent the stirring blade from falling off when replacing the mechanical seal. [Brief description of the drawings]

[0022] [Figure 1] FIG. 2 is a diagram illustrating a stirring device according to an embodiment of the present invention. [Diagram 2] 2 is an enlarged view of the vicinity of the mechanical seal portion of the stirring device of the present embodiment. FIG. [Diagram 3] 4A to 4C are diagrams illustrating a shaft support member according to the embodiment. [Figure 4] 11A to 11C are diagrams illustrating the process of removing the mechanical seal portion in the stirring device of this embodiment. [Diagram 5] FIG. 1 is a diagram illustrating a conventional stirring device. [Figure 6] FIG. 11 is a diagram illustrating a stirring device according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] An agitation device according to one embodiment of the present invention will be described with reference to Fig. 1. Fig. 2 shows an enlarged view of an area A surrounded by a two-dot chain line in Fig. 1, which is in the vicinity of a mechanical seal portion.

[0024] The stirring device 1 has a tank 2 and agitating blade 3, and the stirring blade 3 rotates inside the tank 2 to stir a stirring target 4 in the form of liquid, powder, etc. stored in the tank 2. The stirring blade 3 is driven to rotate inside the tank 2 via a shaft 12 by a rotary drive source such as a motor 11 provided on the top of the tank 2. The shaft 12 extends from the inside to the outside of the tank 2 through a rotation opening 21 provided at the upper end of the tank 2, and is connected to the motor 11 via a coupling (not shown). In addition, a mechanical seal part 13 is arranged at the end of the rotation opening 21 on the outer side of the tank 2 so as to close the rotation opening 21, and holds the shaft 12 so as to generate little dust and rotate stably.

[0025] The tank 2 is a large metal container having an internal storage space several meters in width and height, and is used in, for example, a chemical plant. The storage space contains the mixing blade 3 and stores the object to be mixed 4. The object to be mixed 4 is supplied into the tank 2 and discharged out of the tank 2 via a supply path and a discharge path (not shown) that communicate with the tank 2.

[0026] The tank 2 is also provided with a nozzle insertion part 22 through which a cleaning nozzle for supplying cleaning liquid to the storage space is inserted from outside the tank 2. When changing the type of stirring target 4 or when cleaning the tank 2 periodically, a cleaning nozzle is inserted from the outside through the nozzle insertion part 22, and cleaning liquid is sprayed from the tip of the cleaning nozzle to clean the inner wall of the tank 2. The nozzle insertion part 22 is covered except when the cleaning nozzle is inserted.

[0027] In addition, the tank 2 is provided with a worker's entrance / exit (not shown) for allowing a worker to enter and exit the storage space of the tank 2 during maintenance.

[0028] At the upper end of the tank 2, there is a flat surface 23 that is a plane surrounding the rotation opening 21 and on which the mechanical seal portion 13 is placed, and this flat surface 23 and the storage space of the tank 2 are communicated by the rotation opening 21. The rotation opening 21 has a cross-sectional area that allows at least the movement restriction portion 15 described below to pass through, and in this embodiment, as shown in FIG. 2, the cross-section of the upper end is a circle with a diameter R2, and the cross-sectional area widens halfway, and the cross-section of the lower end is a circle with a diameter R4 larger than R2. The diameter R2 of the upper end of the rotation opening 21 is a diameter that allows the disk-shaped protrusion 131 at the lower end of the mechanical seal portion 13 to be fitted into the rotation opening 21.

[0029] Here, in this description, the rotation opening 21 and the flat surface 23 are collectively referred to as a shaft insertion portion.

[0030] The mechanical seal portion 13 is a known mechanical seal, and surrounds and grips a rod-shaped body (shaft 12 in this embodiment) that penetrates the center. When the mechanical seal portion 13 grips a rod-shaped body, the rod-shaped body can rotate with little dust generation without wobbling around its own center line as the rotation axis, even when the mechanical seal portion 13 is fixed.

[0031] The mechanical seal portion 13 has a mounting surface that contacts the flat surface 23 of the tank 2, is movable toward and away from the tank 2, and is normally fixed to the shaft insertion portion of the tank 2 with the mounting surface in contact with the upper end portion of the tank 2. In this state, the rotation opening 21 is blocked by the mechanical seal portion 13 and the shaft 12 that penetrates the mechanical seal portion 13 and is connected to the mechanical seal portion 13.

[0032] This mechanical seal portion 13 is a so-called expendable item, and needs to be replaced periodically before a problem such as a sealing failure occurs. In this embodiment, the mechanical seal portion 13 is replaced with a new one, for example, once a year. When replacing this mechanical seal portion 13, the weight of the members to be lifted, including the mechanical seal portion 13, is about 200 kg to 500 kg, and therefore it is necessary to lift it up using a crane or the like.

[0033] In this embodiment, the stirring blade 3 is a metallic part, for example, in the shape of a propeller, provided at the lower end of the shaft 12. When the object to be stirred 4 is supplied into the tank 2, the stirring blade 3 is located inside the object to be stirred 4, and when the stirring blade 3 is driven in this state, the object to be stirred 4 moves and is stirred. The stirring blade 3 may not only be provided at the lower end of the shaft 12 as in this embodiment, but may also be provided in multiple stages.

[0034] The driving source of this agitator 3 is the motor 11 located above the tank 2 as described above. The agitator 3 and the motor 11 are connected via a shaft 12 or the like, and the rotational drive of the motor 11 is transmitted to the agitator 3.

[0035] Furthermore, the diameter of the rotation opening 21 does not need to be determined with particular consideration given to the width dimension W1 of the agitating blade 3, and the width dimension W1 of the agitating blade 3 may be larger than the diameter of the rotation opening 21. In this embodiment, when the agitating blade 3 is to be taken out of the tank 2 for maintenance, an operator can enter the tank 2, disassemble the agitating blade 3, and take it out through the operator entrance or the rotation opening 21.

[0036] The shaft 12 is a rod-like body for connecting the motor 11 and the stirring blade 3, and has a cylindrical shape with a uniform cross-sectional area except for a part. In this embodiment, the diameter of the shaft 12 is dimension R1 as shown in Fig. 2, and the minimum diameter of the rotation opening 21 (dimension R2 in this embodiment) is larger than this dimension R1.

[0037] In addition, the shaft 12 of this embodiment is divided into a first shaft 12a located at the top and a second shaft 12b located at the bottom, and the first shaft 12a and the second shaft 12b are connected via a coupling part 14. The coupling part 14 is a known coupling, and is an adjustment mechanism for aligning the rotation axis of the motor 11 with the rotation axis of the second shaft 12b. The stirring blade 3 is provided on the second shaft 12b. In this description, the shaft 12, the stirring blade 3, and the above-mentioned mechanical seal part 13 are collectively referred to as the stirring member.

[0038] As described below, the diameter of the rotation opening 21 does not need to be determined with particular consideration given to the width dimension W2 of the coupling portion 14, and the width dimension W2 of the coupling portion 14 may be larger than the diameter of the rotation opening 21.

[0039] Here, in the present invention, a movement restricting portion 15 is provided on a part of the first shaft 12a. The movement restricting portion 15 is for restricting the movement of the stirring member in the vertical direction, particularly in the downward direction. In this embodiment, it is a protrusion provided on the outer circumferential surface of the first shaft 12a, and as shown in FIG. 2, the maximum dimension in the width direction is dimension R3. This dimension R3 is larger than dimension R1, which is the diameter of the shaft 12, and smaller than dimension R2, which is the minimum diameter of the rotation opening 21.

[0040] The shaft support member of this embodiment is shown in Figure 3. Figures 3(a) and 3(b) are top views of the shaft support member 16, and Figure 3(c) is a front view of the shaft support member 16.

[0041] The shaft support member 16 is a jig that is separate from the tank 2, and is used only when replacing the mechanical seal unit 13. Therefore, during normal operation of the agitator 1, that is, while the mechanical seal unit 13 is fixed to the tank 2 and blocking the rotation opening 21, the shaft support member 16 is removed from the tank 2 and stored in another location.

[0042] In this embodiment, the shaft support member 16 is composed of a plurality of divided members that can be fastened to each other. Specifically, as shown in Fig. 3(a), it is composed of divided members 16a and 16b, each of which is substantially rectangular in front view as shown in Fig. 3(c), and has a substantially "Ω" shape with a curved portion in the center as shown in Fig. 3(a) when viewed from above.

[0043] By arranging these divided members 16a and 16b facing each other and fastening them together with bolts (not shown) or the like, a circular through hole 16c is formed in the center as shown in Fig. 3(b). The diameter R5 of this through hole 16c is larger than the dimension R1 which is the diameter of the shaft 12 and smaller than the dimension R3 which is the maximum dimension of the movement restricting portion 15. Therefore, as shown in Fig. 3(b), the shaft 12 can pass through the through hole 16c, but as shown in Fig. 3(c), the movement restricting portion 15 cannot pass through the through hole 16c.

[0044] Moreover, the width direction dimension d2 of the shaft support member 16 shown in FIG. 3(c) is larger than the diameter R2 of the upper end portion of the rotation opening 21.

[0045] The process in which an operator removes the mechanical seal portion 13 in the stirring device 1 of this embodiment will be described with reference to Fig. 4. Note that, when removing the mechanical seal portion 13, members attached above the mechanical seal portion 13, such as the motor 11 and a coupling (not shown) that connects the motor 11 to the first shaft 12a, have been removed in advance.

[0046] First, after the mechanical seal portion 13 is released from the tank 2, the mechanical seal portion 13 is lifted upward using a crane or the like as shown in Fig. 4(a), and the mechanical seal portion 13 is separated from the shaft insertion portion. At this time, the mechanical seal portion 13 continues to grip the first shaft 12a, and the entire stirring member is lifted.

[0047] As the mechanical seal portion 13 and the stirring member continue to be lifted, the movement restricting portion 15 passes through the rotation opening 21 and is positioned above the upper end surface of the tank 2. At this time, the mechanical seal portion 13 and the stirring member are lifted until the distance d3 between the lower end of the movement restricting portion 15 and the upper end surface of the tank 2 shown in Fig. 4(a) becomes approximately the height dimension d1 of the shaft support member 16 shown in Fig. 3(c). Note that the position where the stirring member including the mechanical seal portion 13 is lifted in this manner and the movement restricting portion 15 is approximately the height dimension d1 of the shaft support member 16 above the tank 2 is called the maintenance position in this embodiment.

[0048] After the stirring member is lifted up to the maintenance position as described above, the first shaft 12a is sandwiched between the divided members 16a and 16b at a position between the lower end of the movement restricting portion 15 and the shaft insertion portion of the tank 2, and the two are fastened together.

[0049] By doing so, the position of the stirring member is maintained at the maintenance position. That is, even if the stirring member is released from the lifting position, the shaft support member 16 acts as a stopper and the movement restricting portion 15 is locked at a position where the shaft support member 16 abuts and supports it from below, as shown in FIG. 4(b). The stirring member will not descend any lower than that. Also, since the width direction dimension d2 of the shaft support member 16 is larger than the diameter d2 of the upper end of the rotation opening 21, the shaft support member 16 does not fall into the tank 2, but is supported by the shaft insertion portion (flat surface 23) of the tank 2.

[0050] Furthermore, when shaft support member 16 is made up of multiple divided members (divided member 16a, divided member 16b) as in this embodiment, and these are fastened together while sandwiching shaft 12 to abut against movement restricting portion 15, it is possible to prevent shaft 12 from falling off shaft support member 16.

[0051] 4(b), after the movement restricting portion 15 is engaged with the shaft support member 16, the mechanical seal portion 13 is released from gripping the first shaft 12a, and the mechanical seal portion 13 is removed from the first shaft 12a. Then, a new mechanical seal portion 13 is attached to the first shaft 12a, and the mechanical seal portion 13 is brought into a state in which it grips the first shaft 12a, thereby completing the replacement of the mechanical seal portion 13.

[0052] Thereafter, the following steps are performed to complete the restoration of the stirring device 1: suspending the mechanical seal portion 13 and the stirring member with a crane and removing the shaft support member 16; gradually lowering the mechanical seal portion 13 and the stirring member until the mechanical seal portion 13 comes into contact with the upper end surface of the tank 2; fixing the mechanical seal portion 13 to the tank 2 after the mechanical seal portion 13 comes into contact with the upper end surface of the tank 2; and finally reconnecting the first shaft 12a and the motor 11.

[0053] By supporting the movement restricting section 15 using the shaft support member 16 as described above, it is possible to prevent the agitator blade 3 and shaft 12 from accidentally falling when replacing the mechanical seal section 13, which would result in damage to the tank 2 and agitator blade 3.

[0054] In this description, the portion of shaft support member 16 that serves to lock movement restricting portion 15 is referred to as the shaft side locking portion, and the portion supported by the shaft insertion portion is referred to as the insertion portion side supported portion. In this embodiment, the upper end of shaft support member 16 is the shaft side supporting portion, and the lower end of shaft support member 16 is the insertion portion side supported portion.

[0055] In this embodiment, the movement restricting portion 15 is provided on the first shaft 12a (not on the second shaft 12b) as described above. That is, the movement restricting portion 15 is provided between the mechanical seal portion 13 and the coupling portion 14. Therefore, even if the movement restricting portion 15 is lifted up to a position above the tank 2 as shown in FIG. 4(a), the coupling portion 14 is still located below the rotation opening 21. Therefore, even if the width dimension W2 (see FIG. 1) of the coupling portion 14 is larger than the diameter R2 of the rotation opening 21, the replacement work of the mechanical seal portion 13 can be performed without problems. In addition, the work of removing the coupling portion 14 inside the tank 2 when replacing the mechanical seal portion 13 is not required.

[0056] As a comparative example of the agitator 1 of the present invention, a conventional agitator drop prevention mechanism is shown in FIG.

[0057] In the stirring device 90 shown in Fig. 5, a protrusion 91 is provided on the shaft 12 as in the above embodiment. A stopper 92 for preventing the shaft 12 and the stirring blade (not shown) provided at the tip of the shaft 12 from falling is provided on the lower end side of the rotation opening 21, and when the shaft 12 and the stirring blade fall freely, the protrusion 91 hits the stopper 92, preventing them from falling further.

[0058] In the agitator 90 configured as described above, the cross-sectional area of ​​the hole provided in the stopper 92 for inserting the shaft 12 is smaller than the cross-sectional area of ​​the rotation opening 21. In this case, if the cleaning liquid is sprayed into the inside of the tank 2 and enters the rotation opening 21, the stopper 92 may make it difficult for the cleaning liquid to flow out, and the cleaning liquid may accumulate in the rotation opening 21 as shown by dots in Fig. 5. If this cleaning liquid flows down during the agitation operation and enters the agitation target 4, a problem may occur in the quality of the agitation target 4.

[0059] In contrast, in the stirring device 1 of the present invention shown in Figures 1 to 4, the mechanism for preventing the shaft 12 from falling is provided only during maintenance and is located outside the tank 2, thereby eliminating the need for a configuration that causes liquid to stagnate near the rotation opening 21.

[0060] Furthermore, as shown by the dimensions R2 and R4 in Figure 2, in this embodiment, the rotation opening 21 has a shape in which the cross-sectional area increases from the outside of the tank toward the internal space, making it easier for liquid to flow down, improving the cleanability of the inside of the tank 2.

[0061] In addition, at this time, if the upper part of the movement restricting portion 15 is also provided with an inclination such as a taper as shown in FIG. 2, it is possible to prevent liquid from remaining on the upper part of the movement restricting portion 15.

[0062] The above-described stirring device makes it possible to prevent the stirring blade from falling off when replacing the mechanical seal.

[0063] Here, the stirring device of the present invention is not limited to the above-described form, and may have other forms within the scope of the present invention. For example, the movement restriction portion does not necessarily have to be a protruding portion, and may be a recessed portion provided on the outer circumferential surface of the shaft.

[0064] FIG. 6 shows an embodiment in which the movement restricting portion is a recess, and the shaft 12 has a through-hole-shaped movement restricting portion 25. In this case, when the mechanical seal portion 13 and the shaft 12 are lifted and the movement restricting portion 25 is positioned above the upper end surface of the tank 2, a rod-shaped shaft support member 26 having a diameter smaller than the hole diameter of the movement restricting portion 25 and a length dimension longer than the diameter of the rotation opening 21 penetrates the movement restricting portion 25, so that the mechanical seal portion 13 and the shaft 12 do not descend below the position where the shaft support member 26 hits the upper end surface of the tank 2. In this way, when the movement restricting portion 25 is a recess, the cross-sectional area of ​​the rotation opening 21 may be slightly larger than the cross-sectional area of ​​the shaft 12, so that the cross-sectional area of ​​the rotation opening 21 can be made relatively small. On the other hand, if there is a concern about the strength of the shaft itself by making the movement restricting portion a recess, it is preferable that the movement restricting portion has a protruding shape as shown in FIG. 1, etc. [Explanation of symbols]

[0065] 1 Mixing device 2 Tank 3 Mixing blade 4. Mixing target 11 Motor 12 Shaft 12a First Shaft 12b Second Shaft 13 Mechanical seal part 131 Protrusion 14 Coupling section 15 Movement Control Department 16 Shaft support member 16a Partition 16b Partition 21 Rotation opening 22 Nozzle insertion part 23 Flat surface 25 Movement Control Department 26 Shaft support member 90 Mixing device 91 Protrusion 92 Stopper

Claims

1. A stirring member having a shaft with stirring blades that rotate to stir the object to be stirred; A tank having an internal space capable of accommodating the stirring impeller and storing the stirring target, and a shaft insertion portion through which the shaft is inserted from the internal space to the outside; a mechanical seal portion provided on the stirring member and fixed to the shaft insertion portion to rotatably grip the shaft; A stirring device comprising: the shaft is provided with a movement restricting portion that restricts vertical movement of the stirring member, a shaft support member including a shaft side locking portion that locks the movement restricting portion and an insertion portion side supported portion that is supported by the shaft insertion portion, When the mechanical seal portion is separated from the shaft insertion portion and the stirring member is moved vertically upward to a maintenance position, the shaft support member is positioned between the movement restricting portion and the shaft insertion portion, whereby the movement restricting portion comes into contact with the shaft side locking portion of the shaft support member, and the insertion portion side supported portion is supported by the shaft insertion portion, thereby maintaining the stirring member in the maintenance position, The stirring device is characterized in that the shaft has a first shaft held by the mechanical seal portion, a second shaft on which the stirring blade is provided, and a coupling portion connecting the first shaft and the second shaft, and the movement regulating portion is provided on the first shaft.

2. 2. The stirring device according to claim 1, wherein the movement restricting portion is a protrusion provided on an outer circumferential surface of the shaft, and the shaft support member abuts against a lower end of the protrusion.

3. 3. The stirring device according to claim 1, wherein the movement restricting portion is a recess provided on an outer circumferential surface of the shaft, and the shaft support member is inserted into the recess.

4. The stirring device described in any one of claims 1 to 3, characterized in that the shaft support member is composed of a plurality of separate members that can each be fastened, and these separate members abut against the movement regulating portion by being fastened while sandwiching the shaft.

5. The stirring device according to any one of claims 1 to 4, characterized in that the shaft support member is separate from the tank and is removed from the tank when the mechanical seal portion is fixed to the shaft insertion portion.

6. 6. A stirring device as described in any one of claims 1 to 5, characterized in that the rotation opening, which is an opening through which the shaft passes in the shaft insertion portion, has a shape whose cross-sectional area increases from the outside of the tank toward the internal space.

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