JP2005016557A - Shaft seal structure, and stirring device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shaft seal structure and a stirring device in which contamination of foreign matters can be prevented, and the maintenance is easy. <P>SOLUTION: A shaft seal structure comprises an inner cylinder 21 which is externally fitted to a rotary shaft 11 and rotated integrally with the rotary shaft 11, and has a first groove 21a formed in the axial direction with the period T on an outer surface thereof and an outer cylinder 22 which is externally fitted over the inner cylinder 21 with a predetermined space therebetween and has a second groove 22a facing the first groove 21a on an inner surface thereof. A labyrinth seal 18 to seal the space after filling gas in the space is provided, and the outer cylinder 22 is movable in the vertical direction. When the outer cylinder 22 is elevated, a passage R of a large sectional area is formed between the inner cylinder 21 and the outer cylinder 22, and CIP and SIP can be performed by supplying pure water and steam to the passage R. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a shaft sealing structure for sealing a rotating shaft and a stirring device using the shaft sealing structure.
[0002]
[Prior art]
In a stirring device for stirring powder and liquid, a stirring blade attached to a rotating shaft is disposed in a stirring tank. The rotating shaft passes through the inside and outside of the stirring tank, and a shaft sealing structure such as an oil seal, a ground seal, and a mechanical seal is disposed between the stirring tank and the rotating shaft. Thereby, the airtightness in the stirring tank is maintained, and the intrusion of dust and the leakage of the sample can be prevented.
[0003]
However, since oil seals, gland seals, mechanical seals, and the like have sliding rotating parts, there is a high possibility that scraps due to wear, lubricating oil components, lubricating liquid components, etc. will enter the agitation tank. In particular, in the case of stirring and mixing pharmaceuticals such as injectable preparations, it is not possible to use a shaft seal structure having only an oil seal or a ground seal because foreign substances are not allowed to enter. Moreover, there is a problem that it is difficult to adopt a shaft seal structure using a mechanical seal.
[0004]
In order to solve the above problem, Patent Document 1 discloses a shaft seal structure having a labyrinth seal. The labyrinth seal includes an inner cylinder integrated with the rotating shaft and an outer cylinder integrated with the stirring tank. A predetermined gap is provided between the inner cylinder and the outer cylinder, and a gas such as nitrogen is supplied to the gap.
[0005]
Thereby, since gas is exhausted to the outside from between the inner cylinder and the outer cylinder, it is possible to prevent the entry of dust and the like from the outside by the gas pressure. Further, since the inner cylinder and the outer cylinder do not slide during rotation of the rotating shaft, no shavings are generated and no lubricating oil is required. Therefore, it is possible to prevent mixing of foreign substances and perform stirring such as mixing of medicines and foods.
[0006]
[Patent Document 1]
JP-A-8-35499 (2nd page-4th page, Fig. 2)
[0007]
[Problems to be solved by the invention]
When the sample is stirred and mixed by the stirring device, the shaft seal structure is cleaned and sterilized to prevent the previous sample from being mixed. However, according to the shaft seal structure using the conventional labyrinth seal, since the gap between the inner cylinder and the outer cylinder is small, the cleaning liquid does not spread and sufficient cleaning cannot be performed.
[0008]
Further, even if steam for sterilization is supplied to the gap, the pressure loss is large and the steam flow rate is reduced. For this reason, the temperature of the inner cylinder and the outer cylinder cannot be sufficiently increased, and a sufficient sterilization effect cannot be obtained. Therefore, CIP (Cleaning In Place) and SIP (Sterilization In Place) cannot be performed, and the labyrinth seal is disassembled and cleaned, so that there is a problem that maintenance of the shaft seal structure becomes complicated.
[0009]
An object of this invention is to provide the shaft seal structure and stirring apparatus which can prevent mixing of a foreign material and are easy to maintain.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a shaft seal structure according to the present invention includes an inner cylinder that is fitted on a rotating shaft, rotates integrally with the rotating shaft, and has first grooves formed on the outer surface at predetermined intervals in the axial direction. And an outer cylinder that is externally fitted with a predetermined gap to the inner cylinder and that has a second groove facing the first groove on the inner surface, and is sealed by injecting gas into the gap The labyrinth seal is provided, and the relative position in the axial direction between the inner cylinder and the outer cylinder is variable.
[0011]
According to this configuration, the first and second grooves are opposed to each other, and the rotating shaft is rotated by injecting gas into the gap between the inner cylinder and the outer cylinder. Thereby, it is possible to rotate the rotating shaft while preventing foreign matter from entering the gap. When the relative position of the outer cylinder is moved in the axial direction with respect to the inner cylinder, the relative positions of the first and second grooves are shifted. Thereby, a passage having a wide cross-sectional area that is alternately bent in the radial direction is formed between the inner cylinder and the outer cylinder. CIP or SIP having a shaft seal structure can be performed by circulating cleaning liquid, steam, or the like through the passage.
[0012]
According to the present invention, in the shaft seal structure having the above-described configuration, the rotating shaft is erected and the outer cylinder can be moved in the vertical direction.
[0013]
According to the present invention, in the shaft seal structure configured as described above, a guide member that is externally fitted to the outer cylinder to guide the outer cylinder, and a flexible packing that covers the guide member and the lower surface of the outer cylinder are provided. It is characterized by that. According to this configuration, the outer cylinder slides up and down with the guide member by the guide member, and the container covering the rotating body connected to the rotation shaft is fixed to the guide member. The scraps and the like generated by sliding between the outer cylinder and the guide member are prevented from entering the container by the packing fixed below the outer cylinder and the guide member.
[0014]
Further, the present invention is characterized in that, in the shaft seal structure having the above-described configuration, the wall surfaces of the first and second grooves are inclined surfaces. According to this configuration, it is possible to prevent the sample and the like remaining at the corners of the bottom surfaces of the first and second grooves during CIP and SIP. Further, when the rotating shaft is erected, the cleaning liquid remaining in the first and second grooves, water droplets by steam, etc. can be allowed to flow down and can be easily dried.
[0015]
Further, the present invention is characterized in that, in the shaft seal structure configured as described above, the amount of movement of the outer cylinder is ½ of the period. According to this structure, the cross-sectional area of the channel | path between the inner cylinder and outer cylinder at the time of CIP or SIP is formed widely.
[0016]
In the shaft seal structure having the above-described configuration, the outer cylinder moves to form a passage having a wider cross-sectional area than the gap, and cleaning or sterilization can be performed by introducing a cleaning liquid, steam, or clean gas into the passage. It is characterized by that.
[0017]
The stirring device of the present invention includes the shaft seal structure of each of the above-described configurations, a stirring blade connected to the inner cylinder, and a stirring tank that covers the stirring blade, and the sample put in the stirring tank is the above It is characterized by stirring by rotation of a stirring blade. According to this configuration, the sample is put into the stirring tank, and the rotating shaft, the inner cylinder, and the stirring blade rotate together to stir the sample.
[0018]
The present invention is also characterized in that, in the stirring device having the above-described configuration, the sample is made of a medicine or food.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing a stirring device according to an embodiment. A stirrer 1 that performs sample agitation and mixing by agitation is provided with a gantry 2 at the rear. The entire apparatus is supported by the gantry 2 and the height is adjusted. A motor 3 is installed on the gantry 2. A reduction gear 4 is connected to the motor 3, and a rotating shaft 11 (see FIG. 2) that can be rotated at a predetermined rotation speed by the reduction gear 4 is suspended from the reduction gear 4.
[0020]
A shaft support portion 6 that supports the rotary shaft 11 is provided below the speed reduction device 4. Below the shaft support 6, there is provided a stirring tank 7 for stirring the sample by a stirring blade 8 that is connected to the rotating shaft 11 and rotates integrally. Above the front part of the stirring tank 7, there is provided a charging part 5 for feeding a sample into the stirring tank 7. A discharger 9 is disposed below the stirring tank 7, and an openable / closable discharge port 10 for discharging the sample after stirring is provided below the discharger 9.
[0021]
FIG. 2 is a side sectional view showing details of the shaft support portion 6. The shaft support 6 is covered with an upper cover 12 and a lower cover 13. The upper cover 12 is fixed to the speed reducer 4 with bolts 31, and the lower cover 13 is fixed to the upper cover 12 with bolts 32. Moreover, the stirring tank 7 (refer FIG. 1) is attached to the lower cover 13 in the airtight state.
[0022]
A bearing 14 is held on the upper portion of the lower cover 13, and the rotating shaft 11 is rotatably supported by the bearing 14. A shaft seal portion 20 having an oil seal 17 and a labyrinth seal 18 is held at the lower portion of the lower cover 13. A stirring blade 8 is attached to the lower end of the rotating shaft 11 penetrating the shaft sealing portion 20 via a boss 19.
[0023]
The oil seal 17 disposed on the upper portion of the shaft seal portion 20 prevents intrusion of foreign matter from above by causing ring-shaped resin or the like to slidably contact the rotating shaft 11 via grease. The details of the labyrinth seal 18 disposed at the lower portion of the shaft seal portion 20 are shown in FIG. The labyrinth seal 18 has an inner cylinder 21 that is fitted on the rotary shaft 11 and rotates integrally with the rotary shaft 11 by a key 28.
[0024]
An outer cylinder 22 is fitted on the inner cylinder 21 via a predetermined gap d1 (see FIG. 4). An upper guide 23 and a lower guide 24 (guide member) that are fastened by bolts 25 are fitted on the outer cylinder 22. Thereby, the outer cylinder 22 is slidably contacted with the upper guide 23 and the lower guide 24, and can move up and down. The upper guide 23 and the lower guide 24 are fixed to the stirring tank 7 through the lower cover 13.
[0025]
A space D is formed between the upper guide 23 and the lower guide 24, and a stopper portion 22 c protruding from the peripheral surface of the outer cylinder 22 is disposed in the space D. The stopper 22c of the outer cylinder 22 comes into contact with the upper guide 23 and the lower guide 24, and the upper limit position and the lower limit position are determined. In the drawing with respect to the center line C, the right side shows a state where the outer cylinder 22 is lowered, and the left side shows a state where the outer cylinder 22 is raised. As a result, the outer cylinder 22 can move with a predetermined stroke S.
[0026]
The lower guide 24 is formed with a hole 24 a that is open on the lower surface of the space D. The hole 24a communicates with the air inlet 16 (see FIG. 2) through a hole 13b provided in the lower cover 13 (see FIG. 2). Thereby, the outer cylinder 22 can be raised by supplying compressed air from the air inlet 16.
[0027]
A spring 26 is sandwiched between the stopper 22c and the upper guide 23, and the outer cylinder 22 is urged downward. Therefore, when the supply of air from the air inlet 16 is stopped, the outer cylinder 22 can be lowered by the biasing force of the spring 26. Further, the upper guide 23 is formed with a hole 23b that is open on the upper surface of the space D. The hole 23b can supply air through a hole (not shown) provided in the lower cover 13 (see FIG. 2). Thereby, air is temporarily supplied from the hole 23b to destroy the adsorption between the stopper 22c and the upper guide 23, and the outer cylinder 22 can be smoothly lowered.
[0028]
O-rings 30 are arranged between the rotary shaft 11 and the inner cylinder 21, between the outer cylinder 22 and the upper guide 23 and the lower guide 24, and between the upper guide 23 and the lower guide 24 and the lower cover 13, respectively. Has been. Thereby, intrusion of dust or the like into the stirring tank 7 from above the labyrinth seal 18 is prevented.
[0029]
An annular packing 27 is attached to the lower surface of the lower guide 24. The inner peripheral side of the packing 27 is fixed to the lower surface of the outer cylinder 22. The packing 27 is made of a flexible material such as resin or synthetic rubber, and follows the movement of the outer cylinder 22. Therefore, it is possible to prevent the scraps of the O-ring 30 caused by sliding between the lower guide 23 and the outer cylinder 22 from entering the stirring tank 7 through the gap between the lower guide 23 and the outer cylinder 22.
[0030]
As shown in the enlarged view of FIG. 4, a plurality of first grooves 21 a that are arranged in parallel in the axial direction at a predetermined period T are formed on the outer surface of the inner cylinder 21. A second groove 22a is formed on the inner surface of the outer cylinder 22 so as to face the first groove 21a when lowered. The groove width of the second groove 22a is narrower than the groove width of the first groove 21a. Thereby, the land part 21g of the inner cylinder 21 can be surely opposed to the land part 22g of the outer cylinder 22.
[0031]
Further, the wall surfaces 21 e and 22 e of the first and second grooves are inclined surfaces having an inclination angle θ with respect to a surface perpendicular to the rotation shaft 11. And the rotating shaft 11 rotates in the state which the 1st, 2nd groove | channels 21a and 22a oppose, and the sample in the stirring tank 7 is stirred.
[0032]
In FIG. 3, a through hole 22 b is formed in a substantially central portion of the outer cylinder 22 in the axial direction, and a hole 23 a communicating with the through hole 22 b is formed in the upper guide 23. A seat portion 22d is formed in the through hole 22b so that the through hole 22b and the hole portion 23a communicate with each other even if the outer cylinder 22 moves up and down. The hole 23b communicates with the inflow port 15 (see FIG. 2) through a hole 13a provided in the lower cover 13 (see FIG. 2). The lower cover 13 is provided with an outlet 13c (see FIG. 2) for exhausting the gas supplied from the inlet 15.
[0033]
When a gas such as nitrogen is supplied from the inlet 15 to the gap between the inner cylinder 21 and the outer cylinder 22, the gas flows with an appropriate pressure in the gap. A part of the gas flows into the stirring tank 7 through the through hole 22b, and the rest is exhausted from the outlet 13c. That is, only clean gas flows into the agitation tank 7 from the through-hole 22b, and shavings and dust generated in the oil seal 17 above the labyrinth seal 18 are discharged together with exhaust from the outlet 13c. Thereby, it is possible to stir the sample in the stirring tank 7 by preventing dust and the like from flowing into the stirring tank 7 from above through the gap between the inner cylinder 21 and the outer cylinder 22.
[0034]
In addition, since the first and second grooves 21a and 22a are opposed to each other, the gas flow path has a portion with a large cross-sectional area and a portion with a small cross-sectional area. For this reason, an extreme increase in the pressure loss of the gas flowing through the gap between the inner cylinder 21 and the outer cylinder 22 can be suppressed. Therefore, a sufficient sealing effect can be maintained with a small flow rate.
[0035]
When air is supplied from the air inlet 16, the outer cylinder 22 rises. At this time, as shown in FIG. 5, the stroke S of movement of the outer cylinder 22 is ½ of the period T of the first and second grooves 21a, 22a. Thereby, the passage R bent alternately in the radial direction is formed between the inner cylinder 21 and the outer cylinder 22, and the cross-sectional area of the passage R can be maximized.
[0036]
When a cleaning liquid such as pure water is supplied from the inlet 15 into the passage R, the cleaning liquid spreads over the outer surface of the inner cylinder 21 and the inner surface of the outer cylinder 22, and a sufficient cleaning effect can be obtained. Further, when steam is supplied from the inflow port 15, steam having a sufficient flow rate flows in the passage R and the temperature of the inner cylinder 21 and the outer cylinder 22 can be increased. Thereby, the sterilization effect of the outer surface of the inner cylinder 21 and the inner surface of the outer cylinder 22 can be obtained.
[0037]
Therefore, CIP and SIP are possible, and the maintenance of the stirring device 1 can be facilitated. In particular, in the case where the sample to be stirred is a pharmaceutical product or food such as an injection preparation, it is necessary to completely prevent contamination by foreign substances and the sample previously stirred. For this reason, the frequency of washing and sterilization is high, and the man-hour reduction effect by CIP and SIP is great.
[0038]
Since the wall surfaces 21e and 22e of the first and second grooves 21a and 22a are inclined surfaces, the pressure loss in the passage R can be reduced and the cleaning liquid and steam can be smoothly distributed. Further, the cleaning liquid and steam can easily reach the corners of the wall surfaces 21e and 22e and the bottom surfaces 21f and 22f of the first and second grooves 21a and 22a.
[0039]
For this reason, it is possible to prevent the sample from remaining in the corner. The corner may be formed into a curved surface. In addition, since the axial direction is the vertical direction, water droplets or cleaning liquid generated by steam can flow down the wall surfaces 21e and 22e, and the surfaces of the inner cylinder 21 and the outer cylinder 22 can be easily dried.
[0040]
In this embodiment, since cleaning and sterilization are performed using pure water and steam, the inner cylinder 21 and the outer cylinder 22 are formed of a material that does not generate rust (for example, ceramic such as alumina or stainless steel). Moreover, since ceramic and stainless steel have solvent resistance and chemical resistance, organic solvents and chemicals can be used as the cleaning liquid. A clean gas may be used for cleaning or sterilization.
[0041]
The shaft seal structure of the present invention is not limited to this embodiment, and can be widely used for apparatuses that require cleaning and sterilization and processing apparatuses that dispose of foreign materials.
[0042]
【The invention's effect】
According to the present invention, since the relative positions in the axial direction of the inner cylinder having the first groove and the outer cylinder having the second groove of the labyrinth seal are made variable, the positions of the first and second grooves facing each other during cleaning and sterilization And a passage having a wide cross-sectional area can be formed between the inner cylinder and the outer cylinder. Therefore, it is possible to obtain a shaft seal structure and an agitating device which prevent foreign matters from being mixed and enable CIP and SIP to facilitate maintenance.
[0043]
According to the present invention, since the guide member for guiding the movement of the outer cylinder and the flexible packing for covering the lower surface of the guide member and the outer cylinder are provided, the shaving generated by the sliding between the outer cylinder and the guide member is provided. The outflow of debris and the like can be prevented by packing.
[0044]
Further, according to the present invention, since the wall surfaces of the first and second grooves are inclined surfaces, the pressure loss in the passage formed between the inner cylinder and the outer surface during cleaning and sterilization is reduced, so that the cleaning liquid and steam can be made smooth. It can be distributed. Further, since the cleaning liquid and steam can easily reach the corner between the wall surface and the bottom surface of the first and second grooves, it is possible to prevent the sample from remaining in the corner. In addition, when the axial direction is the vertical direction, water droplets or cleaning liquid generated by steam can flow down the wall surface, and the surfaces of the inner cylinder and the outer cylinder can be easily dried.
[0045]
Further, according to the present invention, the amount of movement of the outer cylinder is ½ of the period of the first and second grooves, so that the cross-sectional area of the passage formed between the inner cylinder and the outer surface during cleaning and sterilization is the widest. can do.
[Brief description of the drawings]
FIG. 1 is a side view showing a stirring device according to an embodiment of the present invention.
FIG. 2 is a side sectional view showing a shaft support portion of the stirring device according to the embodiment of the present invention.
FIG. 3 is a side sectional view showing a labyrinth seal of the stirring device according to the embodiment of the present invention.
FIG. 4 is a side sectional view showing details of a labyrinth seal of the stirring device according to the embodiment of the present invention.
FIG. 5 is a side sectional view showing details of a labyrinth seal of the stirring device according to the embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Stirring apparatus 2 Base 3 Motor 4 Reduction gear 5 Input part 6 Shaft support part 7 Stirrer tank 8 Stirrer blade 9 Discharge machine 10 Discharge port 11 Rotating shaft 12 Upper cover 13 Lower cover 14 Bearing 17 Oil seal 18 Labyrinth seal 20 Shaft seal part 21 Inner cylinder 21a First groove 22 Outer cylinder 22a Second groove 23 Upper guide 24 Lower guide 27 Packing 30 O-ring

Claims (8)

An inner cylinder that is externally fitted to the rotation shaft and rotates integrally with the rotation shaft and has a first groove formed on the outer surface at a predetermined cycle in the axial direction, and an outer cylinder having a predetermined gap with respect to the inner cylinder A labyrinth seal that is fitted and sealed by injecting gas into the gap, and has an outer cylinder formed on the inner surface. A shaft sealing structure characterized in that the relative position in the axial direction is variable. The shaft seal structure according to claim 1, wherein the rotating shaft is erected and the outer cylinder can be moved in a vertical direction. The shaft according to claim 2, further comprising: a guide member that is externally fitted to the outer cylinder and guides the outer cylinder; and a flexible packing that covers a lower surface of the guide member and the outer cylinder. Sealed structure The shaft seal structure according to any one of claims 1 to 3, wherein the wall surfaces of the first and second grooves are inclined surfaces. The shaft seal structure according to any one of claims 1 to 4, wherein an amount of movement of the outer cylinder is ½ of the period. A passage having a cross-sectional area wider than the gap is formed by the movement of the outer cylinder, and cleaning or sterilization is enabled by introducing a cleaning liquid, steam or clean gas into the passage. The shaft seal structure according to any one of 5. A shaft seal structure according to any one of claims 1 to 6, a stirring blade connected to the inner cylinder, and a stirring tank covering the stirring blade, and a sample put into the stirring tank The stirring device is characterized by stirring by the rotation of the stirring blade. The stirring device according to claim 6, wherein the sample is made of a medicine or food.

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