JP2005133852A - Contamination-free corrosion-proof shaft sealing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a contamination-free corrosion-proof shaft sealing device capable of being properly used in a rotating apparatus on which the contamination is undesirable, such as a stirring machine used in a manufacturing process of medical supplied, chemicals and the like. <P>SOLUTION: In the normal operation, a seal gas is blown out from a gas passage 8 between sealed end faces as opposite end faces of carbon or aluminum stationary seal ring 4 and an aluminum rotating seal ring 6. In the sterilizing work, a sterilization gas for the seal gas is blown out between the seal end faces from the gas passage 8. A seal case part 31 kept into contact with the fluid in a machine is made out of ceramics, and the gas passage 8 is formed on the seal case part 33 excluding the seal case part 31. A cover 101 of a jacket structure is mounted on the seal case 3, and an area surrounded by the heat insulating cover 101 is kept at 121°C or higher by introducing the steam 191 to an internal space 106 of the cover 101 in the sterilizing work. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a contamination-resistant shaft seal device that can be suitably used for a rotating device such as a stirrer used in a manufacturing process of pharmaceuticals, medicines, etc., and that is free from contamination due to generation of metal ions or bacteria. Is.

  As a shaft seal device used for a rotating device such as a stirrer, a device using a single or double end surface contact type mechanical seal or a device using a gland packing is generally known.

  That is, a single-sided end-contact type mechanical seal (hereinafter referred to as “first conventional shaft seal device”) has a seal case attached to the rotating shaft penetrating portion of the casing of the rotating device and a stationary provided in the seal case. The sealing ring is pressed against a rotating sealing ring provided on the rotating shaft, and the in-machine region is sealed by a relative rotational sliding contact action of the sealing end surfaces as opposed end surfaces of both sealing rings. In addition, two double-sided mechanical seals that have the same structure as the first conventional shaft seal device are arranged in parallel in the axial direction for those that use double-end mechanical seals (hereinafter referred to as “second conventional shaft seal device”). Thus, the inside of the equipment casing is sealed through a sealing fluid sealing region formed between the two mechanical seals. As the sealing fluid, oil or a liquid that does not interfere with the in-machine region is used. When oil is used, an oil unit is provided to circulate the oil so that the oil does not leak from the sealed area to the in-machine area H. In addition, when using a liquid that does not interfere with the in-machine area, the pressure of the liquid is made higher than the pressure in the in-machine area to completely prevent leakage of the in-machine fluid into the sealed area. . In the case of using a gland packing (hereinafter referred to as “third conventional shaft seal device”), a stuffing box is attached to the rotating shaft penetrating portion, and an appropriate number is provided between the staffin box and the rotating shaft passing therethrough. The gland packing (generally, braided packing is used) is loaded in parallel to seal the in-machine region. In general, a lantern ring is arranged in the middle of the gland packing group so as to supply nitrogen gas.

  However, all of these conventional shaft seal devices have insufficient measures to prevent contamination, so that the shaft of a rotating device that dislikes contamination such as a stirrer used in the manufacturing process of pharmaceuticals, pharmaceuticals, etc. It was inappropriate as a sealing means.

  That is, in such a rotating device, the inner peripheral surface of the casing and the outer peripheral surface of the rotating shaft are subjected to glass lining or fluororesin lining (generally, polytetrafluoroethylene resin lining) to ensure corrosion resistance and to be regularly The inside of the casing is sterilized by injecting a sterilizing gas (generally, steam) as needed or necessary.

  However, when the first and second conventional shaft seal devices are used, since both sealed end surfaces are in contact with each other, even if the sterilizing gas is injected into the shaft seal device, the sealed end surfaces are sufficiently sterilized. Absent. In particular, in the second conventional shaft seal device having a complicated structure, there are many portions where the sterilization gas does not spread sufficiently, and sterilization is extremely insufficient. In addition, since it is an end-face contact type mechanical seal, during operation, wear powder may be generated due to contact between both sealed end faces, which may enter the in-machine area (inside the casing), avoiding contamination. Can not. Further, in the first and second conventional shaft seal devices, since the seal case and the like are made of metal, a part of the seal case may come into contact with the in-machine fluid (fluid in the casing) to corrode or generate metal ions. In this respect, the prevention of contamination is not sufficient. In addition, since the first conventional shaft seal device cannot completely prevent leakage of the in-machine fluid, if the in-machine fluid is toxic or offensive odor, the surrounding environment is deteriorated.

  Further, when the third conventional shaft seal device is used, the sterilization cannot be sufficiently performed even if the sterilization gas is directly injected to the gland packing. In addition, during operation, the gland packing may generate dust due to contact with the rotating shaft and enter the casing. Therefore, as in the case where the first and second conventional shaft seal devices are used, contamination cannot be sufficiently prevented.

  The present invention does not cause such problems, and is a contamination-free shaft shaft that can be suitably used for a rotating device that dislikes contamination, such as a stirrer used in a manufacturing process of pharmaceuticals, medicines, and the like. Providing equipment.

  The contamination-resistant shaft seal device of the present invention includes a seal case attached to a rotating shaft penetrating portion formed in a casing of a rotating device, a stationary seal ring made of carbon or alumina fixed to the seal case, A spring retainer placed on the outer side of the sealing ring and fixed to the rotating shaft of the rotating device, and a corrosion-resistant material placed between the stationary sealing ring and the spring retainer and interposed between the rotating shaft and the rotating retainer. A rotary sealing ring made of alumina, which is inserted and held so as to be movable in the axial direction in a state where it is secondarily sealed by a first O-ring, and a rotary sealing ring interposed between the rotary sealing ring and the spring retainer. A spring member that presses and urges the stationary seal ring into the stationary seal ring, a series of gas passages that pass through the seal case and the stationary seal ring and open between the sealed end faces that are the opposite end faces of both seal rings, A gas ejection mechanism that selectively ejects gas from the gas passage between the sealed end faces. During normal operation, the seal gas is ejected between the sealed end faces to keep the sealed end faces in a non-contact state. The seal case is configured to exert a sealing function at the relative rotation portion of the sealed end face, and to sterilize the sterilizing gas between the sealed end faces instead of the seal gas during the sterilization operation, and to contact the in-machine fluid. The gas passage is formed in a seal case part other than the part made of ceramics while the part is made of ceramics. In such a shaft seal device, the seal cover is a cylindrical cover that surrounds the shaft seal device portion protruding to the outside region of the machine and seals the portion through which the rotary shaft passes, and has a peripheral wall. A heat insulation cover having a hollow jacket structure is attached, and at the time of sterilization work, steam is introduced into the inner space of the peripheral wall, so that the region surrounded by the heat insulation cover is maintained at a temperature of 121 ° C. or higher. It is preferable to keep it. The spring retainer is formed with a cylindrical holding portion that surrounds the outer peripheral portion of the rotary seal ring, and a pair of second O's arranged in parallel in the axial direction in an annular O-ring groove formed on the outer peripheral portion of the rotary seal ring. The ring is engaged and held to form an annular space sealed by both second O-rings between the opposed peripheral surfaces of the rotary sealing ring and the holding portion of the spring retainer. It is preferable to form a seal gas introduction path that communicates with the space. In a preferred embodiment, the shaft seal device of the present invention is installed in a rotating device in which a glass lining or a fluororesin lining is applied to a casing and a rotating shaft.

  In the shaft seal device of the present invention, since the seal ring and the seal case portion that come into contact with the in-machine fluid are made of non-metallic material such as alumina having corrosion resistance, corrosion due to contact with the in-machine fluid or metal ions Contamination due to will not occur. Further, by supplying a sealing gas having a pressure higher than that of the fluid inside the machine between the sealed end faces, the inside of the machine is sealed while maintaining the sealed end face in a non-contact state, so that leakage from the inside of the machine can be completely prevented. At the same time, there is no case where wear powder is generated by the contact of the sealing end face and enters the machine. Moreover, since a sterilizing gas such as steam can be ejected from between the sealed end faces to the inner and outer peripheral sides, the shaft seal device portion facing the inside of the machine is effectively sterilized, including the sealed end faces that are particularly difficult to sterilize. be able to.

  Therefore, according to the present invention, it is possible to provide a contamination-resistant shaft seal device that can be suitably used for a rotating device that dislikes contamination such as a stirrer used in a manufacturing process of pharmaceuticals, medicines, and the like. it can.

  The configuration of the present invention will be specifically described below with reference to FIGS.

  1 and 2 show an example of a shaft seal device 1 according to the present invention. This shaft seal device 1 is a bowl-shaped stirrer used in a manufacturing process of pharmaceuticals, medicines, etc., as shown in FIG. Equipped with 2. That is, as shown in FIG. 6, the stirrer 2 includes a cylindrical casing 21 in which a shaft penetrating portion 20 having an annular flange 20a is formed at the center of the upper wall, and a stirring shaft extending in the vertical direction. A rotary shaft 22 that is rotatably supported by a support frame (not shown) standing on the upper wall of the casing 21 and has a lower side suspended from the shaft penetration portion 20 into the casing 21, and a lower end of the rotary shaft 22 And a motor 24 that is supported by the support frame and rotates the rotating shaft 22. The shaft seal device 1 is provided between the shaft penetrating portion 20 and the rotating shaft 22. The space between the in-machine region (region in the casing 20) H and the out-of-machine region (atmosphere region) L is interposed. Note that glass lining (or fluororesin lining such as polytetrafluoroethylene) is applied to the inner peripheral surface of the casing 21 and the lower outer peripheral surface of the rotating shaft 22.

  As shown in FIGS. 1 and 2, the shaft seal device 1 includes a seal case 3 attached to a shaft penetrating portion 20 formed in a casing 21 of the stirrer 2, a stationary seal ring 4 fixed to the seal case 3, and A spring retainer 5 disposed on the outer side (upper side) of the stationary seal ring 4 and fixed to the rotating shaft 22, and disposed between the stationary seal ring 4 and the spring retainer 5, and fitted and held on the rotating shaft 22. Rotating sealing ring 6 formed, spring member 7 interposed between rotating sealing ring 6 and spring retainer 5, opposing end surfaces of both sealing rings 4 and 6 passing through seal case 3 and stationary sealing ring 4 A series of gas passages 8 opened between the sealed end faces 40 and 60, and a seal gas 90 or sterilization gas 91 having a pressure higher than the pressure in the in-machine region H (pressure in the casing 21) is selectively passed from the gas passage 8 to the sealed end face 40. , Erupt between 60 A gas ejection mechanism 9, a non-contact type mechanical seal of the static pressure type comprising a vibration isolating mechanism 10 for preventing vibration of the rotary seal ring 6.

  As shown in FIG. 1, the seal case 3 is in close contact with the first ring 31, the second ring 32 fitted to the outer periphery of the first ring 31, and the upper surfaces of the first and second rings 31 and 32. In a state separated from the third ring 33, the annular protrusion 32 a protruding from the inner peripheral portion of the lower end of the second ring 32 is engaged with the annular recess 31 a formed at the outer peripheral portion of the lower end of the first ring 31. The second ring 32 is tightly fixed to the lower surface portion of the third ring 33 by an appropriate number of bolts 34, thereby being assembled into an integral structure. In this way, the cylindrical seal case 3 formed by assembling the first to third rings 31, 32, 33 into an integral structure is formed between the first ring 31 and the flange 20 a of the shaft penetrating portion 20 as shown in FIG. 1. An appropriate number of bolts 37 and nuts are attached to the mounting ring 36, the second ring 32, and the third ring 33 engaged with the lower surface of the flange 20a of the shaft penetrating portion 20 with the annular gasket 35 interposed therebetween. It is attached to the shaft penetrating portion 20 by fastening with 38. By the way, the 1st ring 31 which is a seal case part which contacts an in-machine fluid (fluid in the casing 21) is comprised with ceramics (for example, alumina) rich in corrosion resistance and heat resistance. On the other hand, the third ring 33 that does not come into contact with the in-machine fluid when the stationary seal ring 4 to be described later is fitted, and the second ring 32 and the mounting ring 36 that are disposed in the outside area L are made of a metal material such as SUS304. Has been. The gasket 35 has a composite structure including a core body made of an elastic material such as rubber and a bag body made of a corrosion-resistant material such as polytetrafluoroethylene that covers a portion excluding the outer peripheral portion of the core body. .

  The stationary sealing ring 4 is an annular body, and is fitted and fixed to the inner peripheral portion of the third ring 33 of the seal case 3 while being loosely fitted to the rotary shaft 22 as shown in FIG. An annular protrusion 33 a having the same inner diameter as the inner diameter of the first ring 31 is formed on the inner periphery of the upper end of the third ring 33, and the stationary sealing ring 4 is located on the inner peripheral side of the annular protrusion 33 a and the first ring 31. A pair of O-rings 41 and 41 are fitted and fixed between the opposite end surfaces of the upper end portion 31b. Since the stationary seal ring 4 is fitted and fixed to the inner periphery of the third ring 33 in this state, the third ring 33 does not contact the in-machine fluid. Each O-ring 41 is made of a fluorine-based rubber (for example, perfluoro rubber) having excellent corrosion resistance and heat resistance. The stationary seal ring 4 is made of carbon or alumina, and the tip end face (upper end face) is constituted by a smooth sealed end face (hereinafter referred to as “stationary seal end face”) 40.

  As shown in FIG. 1, the spring retainer 5 includes an annular wall portion 50, a cylindrical O-ring locking portion 51 that protrudes downward from the inner peripheral portion thereof, and a cylindrical shape that protrudes downward from the outer peripheral portion of the annular wall portion 50. It is made of metal (for example, SUS304) having the holding portion 52. The spring retainer 5 is configured such that the annular wall portion 50 and the O-ring locking portion 51 are fitted to the rotation shaft 22 and the set screw 53 screwed to the annular wall portion 50 is tightened to the rotation shaft 22 to thereby rotate the rotation shaft 22. It is fixed to. Although the glass lining is applied to the outer peripheral surface of the rotating shaft 22 as described above, the upper end of the glass lining layer 22a is located slightly below the place where the set screw 53 contacts as shown in FIG. Has been.

  As shown in FIG. 1, the rotary sealing ring 6 has an annular ring made of alumina having a smooth sealing end surface (hereinafter referred to as a “rotating sealing end surface”) 60 whose front end surface (lower end surface) is directly opposite to the stationary sealing end surface 40. The first O-ring 61 is disposed between the stationary seal ring 4 and the spring retainer 5 and between the inner peripheral surface of the rotary seal ring 6 and the outer peripheral surface (glass lining layer 22a) of the rotary shaft 22. Is inserted and held on the rotary shaft 22 so as to be movable in the axial direction. The first O-ring 61 is made of a fluorine-based rubber (for example, perfluoro rubber) having excellent corrosion resistance and heat resistance. The downward movement of the first O-ring 61 is prevented by an annular O-ring locking surface 62 formed on the inner periphery of the lower end of the rotary sealing ring 6, and the upward movement is related to the O-ring engagement of the spring retainer 5. It is blocked by the end face of the stop 51. The end surface of the O-ring locking portion 51 is orthogonal to the axis, but the O-ring locking surface 62 is a tapered surface that is inclined in the inner circumferential direction and downward as shown in FIG. As will be described later, the outer peripheral portion of the rotary seal ring 6 is fitted to the holding portion 52 of the spring retainer 5 through a pair of second O-rings 68 and 68 in a state allowing the axial movement of the rotary seal ring 6. Is retained. In addition, a drive collar 63 made of metal (for example, SUS304) is abutted with the base end portion (upper end portion) of the rotary seal ring 6. The drive collar 63 is prevented from rotating relative to the rotary seal ring 6 by engaging a pin 64 projecting therefrom with a recess 65 formed in the rotary seal ring 6.

  As shown in FIG. 2, the spring member 7 is composed of a plurality of coil springs (only one is shown) interposed between the spring retainer 5 and the rotary seal ring 6, and the rotary seal ring 6 is fixed to the stationary seal ring. 4 to generate a closing force that acts in the direction of closing the space between the sealed end faces 40 and 60. The spring member 7 holds the base end portion in a recess formed in the annular wall portion 50 of the spring retainer 5 and presses and urges the rotary seal ring 6 by bringing the tip end portion into contact with the drive collar 63. is there. A through hole 50a is formed in the annular wall portion 50 of the spring retainer 5, and a drive pin 66 inserted from above into the through hole 50a is screwed to the drive collar 63, whereby the rotary seal ring 6 is connected to the spring retainer. 5 is allowed to be relatively unrotatable while allowing axial movement.

  2 and 3, the gas passage 8 is a space formed in a fitting portion between the third ring 33 and the stationary sealing ring 4 of the seal case 3, and is formed by a pair of upper and lower O-rings 41 and 41. A sealed annular communication space 81, a case side passage 82 that penetrates the third ring 33 in the radial direction to reach the communication space 81, and a plurality of static pressure generation grooves 83 formed in the stationary sealing end surface 40; The seal ring side passage 84 extends from the communication space 81 to the static pressure generating grooves 83 through the stationary seal ring 4. As shown in FIG. 4, the static pressure generating grooves 83 are arcuate concave grooves that are concentrically arranged in parallel with the stationary sealing end face 40, and the downstream end of the sealing ring side passage 84 is branched. The branch portions 84a are opened in the respective static pressure generating grooves 83.

  As shown in FIG. 1, the gas ejection mechanism 9 connects a gas supply path 92 to a case side passage 82 formed in the seal case 3, and is led from a seal gas supply source 93 to the upstream end of the gas supply path 92. The seal gas supply path 94 and the sterilization gas supply path 96 led from the sterilization gas supply source 95 are branched and connected, and the seal gas supply valve 94 a provided in the seal gas supply path 94 and the sterilization gas provided in the sterilization gas supply path 96 are connected. By opening and closing the supply valve 96a, the seal gas 90 or the sterilization gas 91 is jetted from the gas passage 8 between the sealed end faces 40 and 60. The seal gas supply path 94 is provided with a pressure regulating valve 94b, a flow rate controller 94c, a pressure gauge 94d, and the like, so that the seal gas 90 having a pressure higher than the pressure in the in-machine region H is supplied and ejected. . Further, the intermediate portion of the gas supply path 92 includes two branch paths 92a and 92a that are selectively used as necessary. Each branch path 92a is provided with an appropriate filter 92b.

  Thus, in the normal operation where the shaft seal function by the shaft seal device 1 is required, the pressure in the in-machine region H is controlled by opening the seal gas supply valve 94a and closing the sterilization gas supply valve 96a. A higher-pressure seal gas 90 is supplied from the seal gas supply path 94 to the static pressure generating grooves 83 through the gas supply path 92, the case side passage 82, the communication space 81, the seal ring side passage 84, and the both sealed end faces 40. , 60 generates a static pressure to keep it in a non-contact state. As the seal gas 90, a gas inert to the in-machine fluid is used, and in this example, nitrogen gas is used. In addition, if necessary, a restrictor such as an orifice, a capillary tube, or a porous member is provided at an appropriate position of the gas passage 8 (sealed ring side passage 84, etc.), and the clearance between the sealed end faces 40, 60 is automatically adjusted. Configured to be That is, when the clearance between the sealed end faces 40, 60 becomes large due to vibration of the rotary device (stirrer 2), the amount of seal gas flowing out between the sealed end faces 40, 60 from the static pressure generating groove 83, and the restrictor are reduced. The amount of seal gas supplied to the static pressure generating grooves 83 is imbalanced, and the pressure in the static pressure generating grooves 83 decreases, so that the opening force becomes smaller than the closing force. The gap is changed so as to be small, and the gap is adjusted to an appropriate one. On the contrary, when the gap between the sealing end faces 40 and 60 becomes small, the pressure in the static pressure generating grooves 83 increases due to the same action as described above, and the opening force becomes larger than the closing force, and the sealing end face It changes so that the clearance gap between 40 and 60 may become large, and the clearance gap is adjusted to an appropriate thing.

  When the shaft sealing function by the shaft sealing device 1 is not required and the sterilization operation in the machine (inside the casing 21) is performed, the sterilization gas supply valve 96a is opened and the seal gas is supplied. By closing the valve 94a, the sterilization gas 91 having an appropriate pressure (for example, the same pressure as the seal gas 90) is supplied from the sterilization gas supply passage 96 to the gas supply passage 92, the case side passage 82, the communication space 81, and the sealing ring side. It is supplied to the static pressure generating grooves 83 through the passage 84. As the sterilizing gas 91, the same sterilizing gas used for the sterilization treatment in the casing 21 is used. In this example, high-temperature steam (steam) is used. The sterilization gas supply source 95 can also be used as a sterilization gas supply source in the sterilization processing system in the casing 21.

  Further, as shown in FIG. 2, the seal case 3 includes a shaft seal device portion (a tip portion (upper end portion) of the stationary seal ring 4, a spring retainer 5) and a rotary seal. A metal heat insulating cover 101 surrounding the ring 6 or the like is attached. The heat insulating cover 101 includes a cylindrical peripheral wall 102 that concentrically surrounds the shaft seal device portion, and a disk-shaped end wall 103 that is provided at one end (upper end) of the rotating shaft 22 and passes therethrough. An end wall portion through which the rotary shaft 22 passes is sealed with an oil seal 104 provided on the cylindrical cover, and the other end portion (upper end portion) of the peripheral wall 102 and the end portion on the outside area side of the seal case 3, The third ring 33 is attached to the third ring 33 in a state where the upper end of the third ring 33 is sealed by the O-ring 105. The peripheral wall 102 has a hollow jacket structure, and a steam introduction port 107 and a drain port 108 communicating with the internal space 106 are provided at an upper end portion and a lower end portion of the peripheral wall 102. Steam 191 is introduced into the internal space 106 of the peripheral wall 102. An area surrounded by the heat insulating cover 101 and within the cover 101 sealed by the oil seal 104 and the O-ring 105 (hereinafter referred to as “in-cover area”) 109 has a sealed end face 40 during sterilization. , 60 is introduced as a sterilizing gas, and the steam 91 is discharged from the pressure holding passages 110 and 111 provided in the seal case 3 to the outside of the in-cover region 109. The pressure holding path includes a first pressure holding path 110 formed in the third ring 33 with one end opened to the cover inner region 109, and a second pressure holding path 111 connected to the first pressure holding path 110. It consists of. The second pressure holding path 111 is provided with a pressure holder 112 such as a steam trap and a relief valve so that when the steam 91 is introduced into the in-cover area 109, the area 109 is held at a predetermined pressure. It has become. Thus, the conditions for introducing steam 191 into the internal space 109 of the peripheral wall 102 and the pressure holding condition of the in-cover region 109 by the pressure holder 112 are maintained at 121 ° C. or higher, which is the sterilization condition of the medicine in the cover. Is set to

  As shown in FIG. 3, the vibration isolation mechanism 10 includes a holding portion 52 of the spring retainer 5 that surrounds the outer periphery of the rotary seal ring 6, and a pair of annular O-ring grooves 67 formed on the outer periphery of the rotary seal ring 6. 67, a pair of second O-rings 68 and 68 that are engaged and held in the respective O-ring grooves 67 and are arranged in parallel in the axial direction, and formed between opposing circumferential surfaces of the rotary seal ring 6 and the holding portion 52 of the spring retainer 5. And an annular space 11 sealed by the second O-rings 68 and 68 and a plurality of seal gas introduction passages 12 formed in the rotary seal ring 6.

  Each second O-ring 68 is made of an incompressible elastic material (fluorine rubber or the like) excellent in corrosion resistance and heat resistance, and is between the bottom surface of the O-ring groove 67 and the inner peripheral surface of the holding portion 52. Are packed in a moderately compressed state (a state in which the axial movement of the rotary sealing ring 6 is not hindered), and both axial ends of the annular space 11 are sealed. As shown in FIG. 3, each seal gas introduction path 12 passes through the rotary seal ring 6, and one end portion opens to the rotary seal end surface 60 and the other end portion opens to the annular space 11. As shown in FIG. 5, one end opening of each seal gas introduction passage 12 is directly opposed to the static pressure generating groove 83, and the opening diameter is set to be the same as or smaller than the groove width of the static pressure generating groove 83. .

  According to the shaft seal device 1 configured as described above, the in-machine fluid can be satisfactorily sealed without causing contamination.

  That is, during normal operation in which the stirring process is performed by the stirrer 2, if the seal gas 90 is supplied from the gas passage 8 between the sealed end surfaces 40 and 60, the opening that acts in the direction of opening the sealed end surfaces 40 and 60 opens. Force will be generated. This opening force is due to the static pressure generated by the seal gas 90 supplied to the static pressure generating grooves 83. Therefore, the sealing end surfaces 40 and 60 have this opening force and a closing force that acts in a closing direction between the sealing end surfaces 40 and 60 (by the spring member 7 that presses and urges the stationary sealing ring 4 to the rotating sealing ring 6). Are maintained in a non-contact state in which they balance. Then, since the seal gas 90 is higher than the pressure in the in-machine region H, the in-machine fluid does not enter between the sealed end faces 40, 60, and the in-machine region H is completely sealed, which deteriorates the surrounding environment. There is no fear.

  At this time, since the in-machine region H is sealed while the sealing end surfaces 40 and 60 are kept in a non-contact state, the abrasion powder due to the contact of the sealing end surfaces 40 and 60 does not enter the in-machine region H, and contamination. Contamination-free sealing function that does not cause any problems. Further, the seal gas 90 leaks from between the sealed end faces 40 and 60 to the in-machine region H. However, since the seal gas 90 is a nitrogen gas or the like that does not interfere with the in-machine region H, the seal gas 90 There is no problem caused by allowing leakage into the in-flight region H. Further, the shaft seal device portions (sealing rings 4 and 6, the first ring 31 and the O-ring 61) that may come into contact with the in-machine fluid are all made of a non-metallic material having excellent corrosion resistance (and heat resistance). Therefore, the in-machine fluid is not contaminated by metal ions.

  The supply of the seal gas 90 is continuously performed during the operation of the stirrer 2. However, the operation of the stirrer 2 (drive of the rotary shaft 22) is started after the supply of the seal gas 90 is started. It is started after being kept in a proper non-contact state. Further, the supply of the seal gas 90 is stopped after the operation of the stirrer 2 is stopped and after the rotating shaft 22 is completely stopped.

  In addition, the in-machine region H of the agitator 2 is sterilized periodically or as necessary by injecting steam. During such sterilization work, the steam 91 is supplied to the gas passage 8 so that the in-machine region H can be sterilized. The part of the shaft seal device that faces it can be sterilized well.

  That is, when the steam 91 is supplied to the gas passage 8 with the rotary shaft 22 stopped, the steam 91 passes through the gas passage 8 to reach the static pressure generating groove 83. Spray into the region H and the heat insulating cover 101. At this time, the sealed end faces 40 and 60 are in contact with each other, but the steam 91 supplied to the gas passage 8 is a high-pressure gas equivalent to the seal gas 90, so that steam is supplied in the same manner as when the seal gas 90 is supplied. 91 is ejected into the in-machine region H and the heat insulating cover 101 while opening the sealed end faces 40 and 60.

  Therefore, not only in the gas passage 8 but also the sealed end faces 40 and 60 in contact with each other, the steam 91 contacts uniformly, and sterilization by the steam 91 is performed satisfactorily. At this time, the shaft seal device portions (sealing rings 4 and 6, the first ring 31 and the first O-ring 61) with which the steam 91 spouted from the space between the sealing end faces 40 and 60 to the in-machine region H is in contact are all corrosion resistant and heat resistant. Therefore, there are no problems such as corrosion due to contact with the steam 91 and elution of metal ions. Moreover, since the O-ring locking surface 62 formed on the rotary seal ring 6 is a downward inclined surface, water droplets generated around the first O-ring 61 flow down the O-ring locking surface 62 and are discharged. Therefore, no stagnation occurs and no germs are generated by the stagnation water droplets. Furthermore, even if some dust (abrasion powder or the like) is generated around the first O-ring 61, these are discharged together with the water droplets, and contamination can be further prevented.

  Further, during the sterilization operation, steam 191 is also introduced into the internal space 106 of the heat insulating cover 101, and the cover inner region 109 into which the steam 91 from between the sealed end faces 40 and 60 is introduced is predetermined by the pressure retainer 112. By maintaining the pressure, the in-cover region 109 is kept at a temperature of 121 ° C. or higher, which is a sterilization condition for medicine. Accordingly, each component of the shaft seal device is also held at a high temperature by the temperature of the in-cover region 109, so that the sterilization function by the steam 91 is compared to the case where the steam 91 is simply brought into contact with the surface of the shaft seal device portion. Will be exhibited very effectively, and sufficient sterilization can be performed.

  By the way, in the shaft seal device 1 configured as a static pressure type non-contact type mechanical seal, the seal gas 90 supplied from the gas supply path 8 to the sealed end faces 40 and 60 is compressible. Therefore, a self-excited vibration called a so-called pneumatic hammer is inevitably generated in the seal gas flow path between the sealed end faces 40 and 60. As a result, there is no problem with the stationary seal ring 4 fixed to the seal case 3, but the rotary seal ring 6 that is merely fitted and held on the rotary shaft 22 via the O-ring 61 is described above. Due to the self-excited vibration, the vibration is generated with a minute amplitude equal to or less than the clearance between the sealed end faces 40 and 60, and a vibration sound is generated.

  However, such vibration noise is reliably prevented by the vibration isolation mechanism 10. That is, the seal gas 90 supplied to the static pressure generating groove 83 is held in an appropriate non-contact state between the sealed end faces 40 and 60, and the seal gas 90 supplied between the sealed end faces 40 and 60 is introduced into the seal gas. It introduce | transduces into the annular space 11 from the path | route 12 ..., and the inside of the annular space 11 is hold | maintained with the same pressure as the sealing end surfaces 40 and 60. FIG. Accordingly, each O-ring 68 is pressed against the outer wall surface of the O-ring groove 67 by the seal gas 90 in the annular space 11 and is compressed in the axial direction of the rotary seal ring 6. As a result, since each O-ring 68 is made of an incompressible elastic material, the outer peripheral surface of the rotary seal ring 6 (the bottom surface of the O-ring groove 67) and the holding portion of the spring retainer 5 facing the outer peripheral surface. The pressure contact force of each O-ring 68 to the inner peripheral surface of 52 is increased, and the rotary seal ring 6 is strongly fixed to the inner peripheral surface of the holding portion 52 of the spring retainer 5 via the O-rings 68 and 68. Become. Therefore, a pneumatic hammer (self-excited vibration) does not occur in the seal gas flow path extending between the sealing end faces 40 and 60, so that the rotating seal ring 6 does not vibrate and is generally referred to as “squeal”. No vibration noise is generated.

  As described above, according to the shaft seal device 1 of the present invention, it is possible to satisfactorily seal the in-machine fluid while preventing its contamination, and to avoid contamination due to generation of metal ions, bacteria, corrosion, and the like. The casing 21 and the rotating shaft 22 can be suitably used for various rotating devices in which glass lining, fluororesin (polytetrafluoroethylene, etc.) lining or the like is applied. Such a shaft seal device 1 that is free of contamination and excellent in corrosion resistance is a shaft seal device portion that is in contact with a sterilizing gas 91 such as in-machine fluid or steam and requires a sufficient mechanical strength and corrosion resistance. , 6 and the seal case portion (first ring) 31 can be put into practical use only by being made of the above-mentioned non-metallic material. That is, the stationary seal ring 4 can be made of carbon or ceramics. However, when it is made of ceramics, it is necessary to form the gas passage 8, so that ceramics with poor workability such as silicon carbide are used. It must be made of alumina that cannot be used and has good workability. Also, the rotary seal ring 6 may be made of ceramics such as silicon carbide. However, the seal ring 6 is held in a movable manner in the axial direction, so that the shape of the seal ring 6 becomes complicated. Since the shape is further complicated in order to form the seal gas introduction passage 12, it is necessary that the ceramic is made of alumina having excellent workability. In the above-described example, the shape of the rotary seal ring 6 is further improved by causing the spring member 7 and the drive pin 66 to participate in the rotary seal ring 6 via the metal drive collar 63 without involving the rotary seal ring 6. This simplifies the manufacture of the alumina product and eliminates the disadvantages of the alumina product that is easily damaged by the load of the spring member 7 and the drive pin 66. For the first ring 31, the gas passage 8 is formed in the metal seal case portion (third ring 33) other than the first ring 31, and fastening with the bolt 34 necessary for assembling the seal case 3 and the seal case 3 are attached. A ceramic product which is a brittle material by fastening with bolts and nuts 37 and 38 necessary for attachment to the shaft penetrating portion 20 exclusively by the metal second and third rings 32 and 33 (and the attachment ring 36). The problem (breakage etc. due to bolt fastening) is eliminated.

It is a vertical front view which shows an example of the shaft seal apparatus which concerns on this invention. It is a longitudinal front view of the shaft seal device showing a cross section different from FIG. FIG. 3 is an enlarged detail view of a main part of FIG. 2. It is a cross-sectional plan view of the principal part along the IV-IV line of FIG. It is a cross-sectional bottom view of the principal part in alignment with the VV line | wire of FIG. It is a vertical front view which shows an example of the rotary apparatus (stirrer) equipped with the said shaft seal apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Shaft seal device (static pressure type non-contact type mechanical seal), 1a ... Surface outside surface side surface of shaft seal device, 2 ... Stirrer (rotary device), 3 ... Seal case, 4 ... Static seal ring, 5 ... Spring retainer, 6 ... Rotating seal ring, 7 ... Spring member, 8 ... Gas passage, 9 ... Gas ejection mechanism, 10 ... Anti-vibration / vibration prevention mechanism, 11 ... Annular space, 12 ... Seal gas introduction path, 20 ... Shaft penetration part , 21, casing, 22, rotating shaft (stirring shaft), 22 a, glass lining layer, 31, first ring (a seal case portion that contacts the in-machine fluid), 32, second ring, 33, third ring, 40, Static sealing end face, 52 ... holding part, 60 ... rotary sealing end face, 61 ... first O-ring, 62 ... O-ring locking face, 63 ... drive collar, 67 ... O-ring groove, 68 ... second O-ring, 90 ... Seal gas, 91 ... steam (sterilization , 101 ... thermal insulation cover, 102 ... peripheral wall, 103 ... end wall, 104 ... oil seal, 105 ... O-ring, 106 ... internal space, 107 ... steam inlet, 108 ... drain port, 109 ... area in the cover, 110 , 111 ... Pressure holding path, 112 ... Pressure holder, 191 ... Steam, H ... In-machine area, L ... Atmosphere area (out-of-machine area).

Claims (4)

A seal case attached to a rotating shaft penetrating portion formed in the casing of the rotating device, a carbon or alumina stationary sealing ring fixed to the sealing case, and the rotating device disposed outside the stationary sealing ring. It was placed between the spring retainer fixed to the rotating shaft of the shaft, the stationary seal ring and the spring retainer, and was sealed secondarily by the first O-ring made of a corrosion-resistant material interposed between the rotating shaft and the spring retainer. A rotary seal ring made of alumina that is inserted and held so as to be movable in the axial direction in a state, and a spring member that is interposed between the rotary seal ring and the spring retainer and presses the rotary seal ring to the stationary seal ring And a series of gas passages that pass through the seal case and the stationary sealing ring and open between the sealing end faces that are the opposite end faces of the two sealing rings, and seal gas or sterilization gas is selectively passed from the gas passage to the sealing end face. In a normal operation, the sealing gas is ejected between the sealed end faces so that the sealed end faces are kept in a non-contact state, and the sealing function is performed at the relative rotation portion of the sealed end faces. In the sterilization operation, the sterilization gas is ejected between the sealed end faces instead of the seal gas, and the seal case portion that comes into contact with the in-machine fluid is made of ceramics and the ceramics. The contamination-resistant shaft seal device is characterized in that the gas passage is formed in a seal case part other than the part. A cylindrical cover that seals a portion of the shaft seal device that protrudes to the outside region of the machine and seals a portion through which the rotating shaft passes, and has a heat insulation cover having a hollow jacket structure on the peripheral wall. Attached and configured to keep the region surrounded by the heat insulating cover at a temperature of 121 ° C. or more by introducing steam into the inner space of the peripheral wall during sterilization work. 1. A contamination-resistant shaft seal device according to 1. A cylindrical retainer that surrounds the outer periphery of the rotary seal ring is formed on the spring retainer, and a pair of second O-rings arranged in parallel in the axial direction are formed in an annular O-ring groove formed on the outer periphery of the rotary seal ring. An annular space sealed by both second O-rings is formed between the opposed peripheral surfaces of the rotary sealing ring and the holding portion of the spring retainer, and the rotary sealing ring includes a space between the sealing end surfaces and the annular space. The contamination-resistant shaft seal device according to claim 1 or 2, wherein a seal gas introduction path that communicates with each other is formed. The contamination-resistant shaft according to claim 1, 2 or 3, wherein the contamination shaft is mounted on a rotating device having a glass lining or a fluororesin lining on the casing and the rotating shaft. Sealing device.

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