JP6305865B2 - Outside type mechanical seal - Google Patents

Description

  The present invention relates to an outside-type mechanical seal that can exhibit a good sealing function even when a fluid to be sealed is a slurry liquid containing a solidified component, a solid component, and the like.

  As a conventional outside type mechanical seal, as disclosed in FIG. 1 of Patent Document 1, a cylindrical seal case attached to a shaft seal housing of a rotating device, and the rotating device penetrating the seal case A rotary seal ring fixed to the rotary shaft, a stationary seal ring arranged on the shaft seal housing side from the rotary seal ring and held in the seal case so as to be movable in the axial direction, and between the seal case and the static seal ring And a spring member that presses the stationary seal ring against the rotary seal ring so that the stationary seal ring is pressed against the rotary seal ring. What is configured to shield and seal the in-machine area (sealed fluid area) that is the inner peripheral area of the part and the outer area (atmosphere area) that is the outer peripheral area (hereinafter referred to as “conventional seal”) Known That.

  By the way, in the case of a mechanical seal that exhibits a sealing function by the relative rotational sliding contact action of the sealed end face, when the fluid (sealed fluid) in the in-machine region is a slurry liquid, a solidified component is present in the relative rotational sliding contact part of the sealed end face. Since a slurry component such as solidified and precipitated may not be able to exhibit a good mechanical seal function, a flushing liquid such as fresh water is injected in the vicinity of the relative rotational sliding contact portion in the sealed fluid region. It is preferable to wash and cool the rotating sliding contact portion.

  However, in the inside type mechanical seal as shown in FIG. 4 of Patent Document 1, since the outer peripheral side region of the relative rotational sliding contact portion of the sealed end face is the sealed fluid region, the relative rotational sliding contact portion or By forming a flushing liquid passage that opens in the vicinity thereof, the relative rotational sliding contact portion can be effectively cleaned and cooled by the flushing liquid injected from the flushing liquid passage. In such an outside-type mechanical seal, the inner peripheral side region of the relative rotational sliding contact portion of the sealed end surface becomes a sealed fluid region, so that the relative rotational sliding contact portion is effectively flushed to the seal case due to its structure. A flushing liquid passage that can be formed cannot be formed. That is, when the flushing liquid passage that opens to the sealed fluid region is formed in the seal case, the opening position of the flushing liquid passage is in the vicinity of the base end face of the stationary sealing ring even if the opening position is closest to the relative rotational sliding contact portion. It becomes. That is, in the outside type mechanical seal, no matter what form the flushing liquid passage is formed in the seal case, the flushing liquid cannot be injected in the vicinity of the relative rotational sliding contact portion. It can only be injected in the vicinity of the proximal face of the stationary seal ring that is remote from the part. Therefore, in order to effectively clean and cool the relative rotational sliding contact portion with the flushing liquid, the flushing liquid injected from the flushing liquid passage passes between the opposed peripheral surfaces of the stationary seal ring and the rotating shaft. However, it is extremely difficult for the flushing liquid to flow in this way. The portion cannot be cleaned and cooled effectively.

  For this reason, in the conventional seal, as shown in FIG. 1B of Patent Document 1, a lubricating groove 3L is formed on the inner peripheral portion of the sealing end surface 3A of the stationary sealing ring 3, and the sealed fluid is supplied to the lubricating groove. By guiding to 3L, the relative rotational sliding contact portions of the sealing end faces 3A and 10A are lubricated, cooled and cleaned, and arranged on the inner peripheral side of the stationary sealing ring 3 as shown in FIG. The stirring portion 4 having the stirring blade 4F is provided on the rotating shaft 70, and the sealed fluid is stirred in the inner peripheral side region of the stationary sealing ring 3, thereby cleaning and cooling the relative rotational sliding contact portion. Even when the sealed fluid is a slurry liquid, a quenching liquid such as fresh water is injected from the quenching liquid passage 40 to the outer peripheral side of the relative rotational sliding contact portion as shown in FIG. In combination with this, the slurry component to the relative rotational sliding contact portion Coagulation, is aimed to prevent precipitation.

JP 2006-70942 A

  However, in the conventional seal, the lubrication groove 3L and the agitating portion 4 are provided on the inner peripheral side of the relative rotational sliding contact portion, thereby cleaning and cooling the relative rotational sliding contact portion with a slurry fluid that is a sealed fluid. For this reason, the solidification and precipitation of the slurry component on the relative rotational sliding contact portion cannot be prevented so much and a good mechanical seal function cannot be expected.

  In view of such a point, the present invention can allow the flushing liquid to flow into the inner peripheral side of the relative rotational sliding contact portion of both sealing rings, and the relative rotation even when the sealed fluid is a slurry liquid. It is an object of the present invention to provide an outside type mechanical seal capable of exhibiting a satisfactory mechanical seal function by preventing the solidification and precipitation of slurry components to the sliding contact portion as much as possible.

  The present invention relates to a cylindrical seal case attached to a shaft seal housing of a rotary device, a rotary seal ring fixed to the rotary shaft of the rotary device passing through the seal case, and a shaft seal portion from the rotary seal ring. A stationary seal ring arranged on the housing side and held axially movable in the seal case, and loaded between the seal case and the stationary seal ring, and urged to press the stationary seal ring against the rotary seal ring. And an outer region that is the outer peripheral region of the outer peripheral side region of the relative rotational sliding contact portion by the relative rotational sliding contact action of the sealing end surface that is the opposite end surface of both sealing rings. In the outside type mechanical seal configured to shield the region, in order to achieve the above-described purpose, in particular, the base end portion of the stationary seal ring is axially connected to the inner peripheral portion of the seal case via the O-ring. Transfer The distal end surface of the stationary sealing ring is configured as a sealing end surface having a minute width in the radial direction, and the inner peripheral surface of the distal end portion of the stationary sealing ring is changed from the inner peripheral edge of the sealing end surface to the inner end of the proximal end portion. It is formed in a frustoconical surface that gradually decreases in diameter to the peripheral surface, and the distal end surface of the rotary seal ring is configured as a sealed end surface whose inner diameter is larger than the inner peripheral surface of the base end portion of the stationary seal ring The base end portion of the rotary seal ring is fitted and fixed to a fixed ring fixed to the rotary shaft, and is closed between the opposite peripheral surfaces of the rotary seal ring and the rotary shaft in the stationary seal ring direction. The present invention proposes to form an open cylindrical space and to form a flushing liquid passage in the seal case in the vicinity of the base end face of the stationary sealing ring and opening in the in-machine region.

  In a preferred embodiment of such an outside type mechanical seal, the rotary seal ring and the stationary seal ring are made of ceramics, the radial width of the sealed end face of the stationary seal ring is 1 mm or less, and the balance diameter D0 is It is set so that D1 ≦ D0 ≦ D2 with respect to the inner and outer diameters D1 and D2 of the sealing end face of the stationary sealing ring.

  In the outside type mechanical seal of the present invention, an annular gap opening inward is formed at the abutting portion between the seal case and the shaft seal housing, and the seal case and the shaft are formed on the outer peripheral side portion of the annular gap. It is preferable that an annular gasket for sealing between the sealing portion housing and the flushing fluid passage is opened at the inner peripheral side portion of the annular gap in the vicinity of the base end face of the stationary sealing ring. Further, it is preferable to form a quenching liquid passage that opens to the outside region in the vicinity of the relative rotational sliding contact portion of both sealing rings in the seal case. Further, a set claw in which the mechanical seal is detachably attached to the stationary ring with a stationary side sealing element composed of a seal case and a member attached thereto and a rotary side sealing element composed of a stationary ring and a rotational sealing ring is attached to the stationary ring. It is preferable to use a cartridge-type mechanical seal that is configured to be temporarily connected to the same form as the use form of the mechanical seal.

In the outside type mechanical seal of the present invention, a space that opens in the direction of the stationary seal ring is formed between the rotary seal ring and the rotary shaft, and the inner peripheral surface of the distal end portion of the static seal ring is the frustoconical surface. Accordingly, the flushing liquid injected from the flushing liquid passage that opens close to the base end face of the stationary seal ring is a stationary seal ring having a smaller radial width than the space due to the pressure reducing effect of the space surrounded by the rotating member. Since it can flow into the space from the gap between the rotary shaft and the inner peripheral side of the relative rotational sliding contact portion of both sealing rings, lubrication of the relative rotational sliding contact portion with the fringing liquid is possible. Cooling and cleaning can be performed reliably. Therefore, in combination with the configuration in which the radial width of the sealing end face of the stationary sealing ring is made small to reduce the contact area with the sealing end face of the rotary sealing ring, even when the sealed fluid is a slurry fluid, , solidification of slurry components to between the seal end faces, to prevent the precipitated soluble retroactively, can exhibit a good mechanical seal functions.

FIG. 1 is a sectional view showing an example of an outside type mechanical seal according to the present invention. FIG. 2 is an enlarged detailed view showing the main part of FIG. FIG. 3 is a cross-sectional view corresponding to FIG. 2 showing a modification of the outside type mechanical seal according to the present invention. FIG. 4 is a cross-sectional view corresponding to FIG. 2 showing another modification of the outside type mechanical seal according to the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 and 2. FIG. 1 is a cross-sectional view showing an example of an outside type mechanical seal according to the present invention, and FIG. 2 is a detailed view showing an enlarged main part of FIG.

  An outside-type mechanical seal M shown in FIG. 1 is equipped in a horizontal rotary device that handles a liquid (slurry liquid) containing a slurry component (solidified component, solid component, etc.), and a shaft seal housing of the rotary device. A seal case 2 attached to 1, a stationary seal ring 3 held by the seal case 2, a fixed ring 5 fixed to the rotary shaft 4 of the rotating device passing through the seal case 2 horizontally, and a fixed ring A rotary seal ring 6 fixed to 5, a spring member 7 which is loaded between the seal case 2 and the stationary seal ring 3 and urges the stationary seal ring 3 into pressing contact with the rotary seal ring 6, and a seal The flushing liquid passage 8 and the quenching liquid passage 9 formed in the case 2 are provided, and the relative rotational sliding contact portions of the sealing end surfaces 3a and 6a, which are the opposite end surfaces of the sealing rings 3 and 6, are caused by the relative rotational sliding contact portion. Of S And it is configured and inboard region (the sealed fluid region) A and outside area is its outer circumferential region (atmosphere region) B is a side region so as to shield the seal. In the following description, front and rear mean left and right in FIG.

  As shown in FIG. 1, the seal case 2 includes a cylindrical main body portion 21 that abuts the end surface (front end surface) 1 a of the shaft seal housing 1 and the end portion of the main shaft portion 21 on the shaft seal housing side. It is an integral cylindrical structure made of metal (for example, made of SUS316) that is formed of an annular spring retainer portion 22 that is located in the vicinity of the (rear end portion) and protrudes from the inner peripheral portion of the main body portion 21. The shaft 4 is attached to the shaft seal housing 1 in a state in which the rotating shaft 4 penetrates concentrically. An annular gap 23 opening inward is formed at the abutting portion between the shaft seal housing 1 and the seal case 2. That is, as shown in FIG. 1, the annular gap 23 is formed between the opposed end faces 1 a and 22 a of the shaft seal housing 1 and the spring retainer portion 22. An annular gasket 24 that seals between the housing 1 and the seal case 2 is loaded in a pinched manner.

  As shown in FIG. 1, the stationary seal ring 3 is made of a ceramic (for example, silicon carbide) in which a base end portion 31 is fitted and held on the inner peripheral portion of the seal case 2 via an O-ring 32 so as to be movable in the axial direction. An annular body. That is, as shown in FIG. 2, the stationary seal ring 3 moves the O-ring 32 between the opposed peripheral surfaces 22 b and 31 a of the base end portion 31 and the spring retainer portion 22 of the seal case 2 toward the outside region (forward). Is prevented by an annular step portion 31b formed at the proximal end portion 31 of the stationary seal ring 3, and is prevented from jumping out in the in-machine region direction (backward) by an annular step portion 22c formed at the spring retainer portion 22 of the seal case 2. In such a state, it is held in a state of being squeezed so that it can be moved in the axial direction while being sealed (secondary seal) in the seal case 2.

  As shown in FIG. 2, the front end surface of the stationary sealing ring 3 is configured as a sealing end surface (hereinafter referred to as “stationary side sealing end surface”) 3a that forms an annular plane perpendicular to the axis and having a minute width W in the radial direction. The inner peripheral surface 33a of the distal end portion 33 of the stationary seal ring 3 is a truncated conical surface that gradually decreases in diameter from the inner peripheral edge of the stationary-side sealed end surface 3a to the inner peripheral surface 31c of the base end portion 31 as shown in FIG. Is formed. The radial width W of the stationary side sealing end surface 3a is preferably set to 1 mm or less (optimally 1 mm), and the inclination angle θ of the inner peripheral surface 33a of the distal end portion 33 with respect to the stationary side sealing end surface 3a is 30 ° to 30 °. It is preferable to set to 75 ° (optimally 45 °).

  As shown in FIG. 2, the diameter of the contact surface 22b of the O-ring 32 in the spring retainer portion 22 of the seal case 2, that is, the balance diameter D0 is D1 ≦ D0 ≦ D2 (with respect to the inner and outer diameters D1 and D2 of the stationary sealing end surface 3a). Optimally, D0 = (D1 + D2) / 2) is set. That is, the mechanical seal M is set so that the balance ratio κ is 1 or less, and the axial thrust due to the pressure (back pressure) of the fluid in the in-machine region A (slurry fluid as the sealed fluid) is applied to the stationary seal ring 3. Is configured as a balanced mechanical seal that does not act as much as possible.

  As shown in FIG. 2, the stationary seal ring 3 protrudes from the end surface (front end surface) on the air region side of the spring retainer portion 22 of the seal case 2 into an engagement recess 34 a formed in an annular flange 34 integrally formed on the outer peripheral surface thereof. Relative rotation with respect to the seal case 2 is prevented by engaging the drive pin 22d. The axial length of the seal case 2 is set to be slightly longer than the entire length of the stationary seal ring 3, and the base end surface 31d of the stationary seal ring 3 has a spring retainer portion 22 of the seal case 2 as shown in FIG. In the state where the base end surface 22a is located slightly on the outside region side (front side) (the base end surface 31d is positioned at a position corresponding to the axial intermediate portion of the annular step portion 22c of the spring retainer 22). It is stored in.

  As shown in FIG. 1, the fixed ring 5 is made of a metal (for example, made of SUS316) including a large-diameter fixed part 51 and a small-diameter sealing ring holding part 52 protruding from the end (rear end) of the in-machine region. A set screw 54 which is an annular body and is inserted into the rotating shaft 4 through an O-ring 53 engaged with the inner peripheral portion of the sealing ring holding portion 52 and screwed into the fixing portion 51 is attached to the rotating shaft 4. By tightening, the seal case 2 is disposed on the outside region side (front side) and is detachably fixed to the rotary shaft 4.

As shown in FIG. 1, the rotary sealing ring 6 is made of a ceramic material in which the tip surface facing the stationary side sealing end surface 3a is a sealing end surface (hereinafter referred to as “rotation side sealing end surface”) 6a which is an annular plane orthogonal to the axis. It is an annular body (for example, made of silicon carbide), and a base end portion (front end portion) 61 is fitted and held in a state where an O-ring 62 is interposed in a sealing ring holding portion 52 of a stationary ring 5 and formed on an outer peripheral portion. By engaging the engaging pin 63 with the drive pin 55 projecting from the fixing portion 51 of the fixing ring 5, the driving pin 55 is fixed to the rotating shaft 4 by being arranged on the outside region side (front side) of the stationary sealing ring 3. . That is, the rotary seal ring 6 is fixed to the rotary shaft 4 in a state in which the tip end portion 64 protrudes from the seal ring holding portion 52 of the fixed ring 5 in the stationary seal ring direction (rearward). As shown in FIG. 1 and FIG. 2, a cylindrical shape that is closed by the sealing ring holding portion 52 of the stationary ring 5 and opens in the direction of the stationary sealing ring (rear) is formed between the opposed peripheral surfaces of the tip portion 64 and the rotating shaft 4. The space 10 is formed.

  As shown in FIG. 2, the rotary side sealing end surface 6a has an outer diameter larger than the outer diameter D2 of the stationary side sealing end surface 3a and an inner diameter D3 smaller than the inner diameter D1 of the stationary side sealing end surface 3a. The inner diameter D3 of the end face 6a, that is, the inner diameter of the distal end portion 64 of the rotary seal ring 6 (the outer diameter of the space 10) is the inner diameter of the proximal end portion 31 of the stationary seal ring 3, that is, the inner peripheral surface 33a of the distal end portion 33 which is a frustoconical surface. Is set larger than the base end diameter (maximum diameter) D4. That is, the radial width of the space 10 formed between the distal end portion 64 of the rotary seal ring 6 and the rotary shaft 4 is such that the base end portion 31 of the stationary seal ring 3 and the rotary shaft 4 are as shown in FIG. Is set larger than the radial width of the cylindrical gap passage 11 formed between the opposed peripheral surfaces.

  As shown in FIG. 1, the spring member 7 includes a plurality of coil springs (1) loaded at equal intervals in the circumferential direction between the annular flange 34 of the stationary seal ring 3 and the spring retainer 22 of the seal case 2. The stationary sealing ring 3 is urged so as to be brought into press contact with the rotary sealing ring 6.

  As shown in FIG. 1, the flushing liquid passage 8 includes an upstream portion 81 formed in the upper portion of the main body portion 21 of the seal case 2 and a downstream side formed in the spring retainer portion 22 of the seal case 2 in communication therewith. The downstream portion 82 is opened near the base end surface 31d of the stationary seal ring 3 and is opened in the in-machine region A 82a. That is, as shown in FIG. 2, the downstream portion 82 has an opening 82a in the inner peripheral portion (the inner peripheral portion of the gasket 24) of the annular gap 23 adjacent to the base end face 31d of the stationary sealing ring 3. The flushing liquid 8a is injected toward the periphery of the base end face 31d of the stationary sealing ring 3. As the flushing liquid 8a, clean water or the like which is mixed with the sealed fluid (slurry liquid) and has no trouble is used.

  As shown in FIG. 1, the quenching liquid passage 9 passes through the main body portion 21 of the seal case 2 and is opened to the outboard region B in the vicinity of the relative rotational sliding contact portion S of the sealed end surfaces 3a and 6a. A quenching liquid 9a of the same quality as the flushing liquid 8a is injected toward the vicinity of the outer peripheral side of the relative rotational sliding contact portion S. The main body 21 of the seal case 2 is formed with a drain passage 91 that is arranged at a position different from the quenching liquid passage 9 in the circumferential direction and has the same shape or substantially the same shape as the quenching liquid passage 9. The quenching liquid 9a injected from the quenching liquid passage 9 is recovered.

  By the way, the mechanical seal M is configured as a cartridge type mechanical seal as shown in FIG. 1, and includes a seal case 2 attached to the shaft seal housing 1 and members incorporated therein (stationary seal ring 3 and spring member). 7) A set claw 12 in which a stationary side sealing element consisting of 7) and a stationary ring 5 attached to the rotary shaft 4 and a rotational side sealing element consisting of the rotational sealing ring 6 fixed thereto are detachably attached to the stationary ring 5. By being engaged and connected to the seal case 2, it is configured to be temporarily connected to the same form as the use form of the mechanical seal.

  In other words, the set claw 12 is attached to the fixed portion 51 of the fixed ring 5 by the bolt 13, and the first and second engaging protrusions 12 a and 12 b are integrally formed at the tip portion with a predetermined interval. On the other hand, a cylindrical connecting portion 14 that is concentric with the main body portion 21 having an annular recess 14a formed on the outer peripheral portion is integrally formed at the outer region side end portion (front end portion) of the main body portion 21 of the seal case 2. Yes. Thus, as shown in FIG. 1, the set claw 12 is engaged with the first engaging protrusion 12a between the fixing portion 51 of the fixing ring 5 and the connecting portion 14, and the second engaging protrusion 12b is connected with the connecting portion. 14 using the mechanical seal M by fixing the stationary side sealing element and the rotary side sealing element to the outer peripheral part of the fixing part 51 of the fixing ring 5 with the bolt 13 while being engaged with the 14 annular recesses 14a. It can be integrally connected in the same form as the form. Therefore, the mechanical seal M can be attached to and detached from the shaft seal housing 1 and the rotary shaft 4 as a single unit while remaining in the same form as the usage form, and the mechanical seal M can be attached to the rotating device. In addition, removal from the rotating device and maintenance inspection can be performed efficiently and simply.

In the outside-type mechanical seal M configured as described above, a space 10 that opens in the direction of the stationary sealing ring is formed on the inner peripheral side of the rotation-side sealing end surface 6a, and this space 10 is a rotating member. Since the rotary shaft 4, the sealing ring holding portion 52 of the stationary ring 5, and the distal end portion 64 of the rotary sealing ring 6 are surrounded, the pressure in the space 10 is a stationary seal that is a stationary member. The pressure is lower than the pressure in the gap passage 11 formed between the ring 3 and the ring 3.

  Therefore, the flushing liquid passage 8 is opened 82a toward the inner peripheral side portion (the inner peripheral side of the gasket 24) of the annular gap 23 in which the gasket 24 is loaded, and the injected flushing liquid 8a passes through the inner peripheral side portion. Flushing injected from the flushing liquid passage 8 to a position close to the base end surface 31d of the stationary seal ring 3 together with collision with the end surface 1a of the shaft seal housing 1 constituting the guide shaft and being guided to the gap passage 11. The liquid 8a flows into the space 10 from the gap passage 11. At this time, the diameter D4 of the inner peripheral surface 31c of the base end portion 31 of the stationary sealing ring 3 is smaller than the inner diameter D1 of the stationary sealing end surface 3a and the inner diameter D3 of the rotating sealing end surface 6a, and the radial width of the gap passage 11 is a space. 10 and the radial width of the inner circumferential space 15 of the stationary-side sealing end surface 3a, the gap passage 11 functions as an orifice communicating with both the spaces 10, 15, and the flushing liquid 8a from the gap passage 11 to the space 10 is provided. Inflow is more effective.

  Accordingly, the rotational speed (circumferential speed) at the rotation-side sealed end surface 6a is increased as the centrifugal force on the rotation-side sealed end surface 6a approaches the stationary-side sealed end surface 3a. As indicated by an arrow P in FIG. 2, the liquid 8a is caused to flow from the inner peripheral surface of the tip portion 64 of the rotary seal ring 6 onto the rotary side seal end surface 6a in the outer diameter direction. Then, the flushing liquid 8a that has flowed on the rotation-side sealing end surface 6a and has reached the stationary-side sealing end surface 3a is reversed as shown by an arrow Q in FIG. 3 is allowed to flow along the inner peripheral surface 33a. Such a reverse flow Q is generated more effectively by setting the angle θ of the tapered surface 33a to 35 ° to 75 °, and most effectively by setting θ = 45 °. Done.

  Therefore, the flushing liquid 8a is guided to the contact portion (relative rotational sliding contact portion) S between the stationary sealing end surface 3a and the rotational sealing end surface 6a, and the relative rotational sliding contact portion S is lubricated and cleaned by the flushing liquid 8a. Cooling is performed effectively. As a result, even when the fluid to be sealed is a slurry liquid, solidification and precipitation of the slurry component on the relative rotational sliding contact portion S is prevented as much as possible, and the mechanical seal function is exhibited well. Solidification of slurry components to the relative rotational sliding contact portion S, prevention of precipitation, and cooling of the relative rotational sliding contact portion S are more effectively performed by injecting a quenching liquid 9a into the outer peripheral side of the relative rotational sliding contact portion S. Done.

  Further, since the radial width W of the stationary-side sealed end surface 3a is very small, the slurry component between the sealed end surfaces 3a and 6a is combined with the fact that both the sealed rings 3 and 6 are made of ceramics. Solidification and precipitation are prevented as much as possible. Such prevention of solidification and precipitation by making the stationary-side sealed end face 3a have a minute width is more effectively performed as the radial width W is reduced. On the other hand, if the radial width W of the stationary side sealing end surface 3a is excessively reduced, and if the inclination angle θ of the distal end portion 33 of the stationary sealing ring 3 is increased more than necessary, the stationary side sealing end surface 3a made of ceramic is lost. There is a risk of doing. Therefore, the radial width W of the stationary-side sealing end surface 3a and the taper angle θ of the distal end portion 33 of the stationary-sealing ring 3 can effectively prevent the solidification and precipitation of slurry components while preventing the stationary-side sealing end surface 3a from being lost. Is set as a condition. Specifically, the radial width W of the stationary-side sealing end surface 3a is preferably set as appropriate within a range of 1 mm or less, and is optimally set to W = 1 mm. In addition, the taper angle θ of the distal end portion 33 of the stationary seal ring 3 is preferably set to 35 ° to 75 °, and most preferably set to 45 ° in consideration of the generation of the reverse flow Q.

  Furthermore, the mechanical seal M is configured as a balance type mechanical seal in which the balance diameter D0 is D1 ≦ D0 ≦ D2 with respect to the inner and outer diameters D1 and D2 of the stationary side sealing end surface 3a, and the balance ratio κ is 1 or less. The contact pressure of the stationary side sealing end surface 3a to the rotation side sealing end surface 6a is not increased by the pressure (back pressure) of the sealed fluid. Therefore, even when the pressure in the in-machine region A is high, the contact pressure of the sealed end surfaces 3a and 6a is not excessive, and heat generation due to contact of the sealed end surfaces 3a and 6a and loss of the stationary side sealed end surface 3a are prevented as much as possible. Is done. Then, since heat generation due to contact between the sealed end faces 3a and 6a is prevented as much as possible, the cooling of the sealed end faces 3a and 6a by the flushing liquid 8a and the quenching liquid 9a is more effectively performed, and the sealed end faces 3a and 3a, Solidification of the slurry component due to the heat generation of 6a is also effectively prevented.

  Therefore, according to the outside type mechanical seal M having the above-described configuration, even when the fluid to be sealed is a slurry liquid, a good mechanical seal function can be exhibited.

  The configuration of the outside type mechanical seal according to the present invention is not limited to the above-described embodiment, and can be appropriately improved and changed without departing from the basic principle of the present invention.

  For example, the holding form of the base end portion 31 of the stationary seal ring 3 to the seal case 2 via the O-ring 32 can be configured as shown in FIG. 3 or FIG. That is, in the case shown in FIG. 3, the spring retainer of the seal case 2 is interposed via an O-ring 32 in which the base end portion 31 of the stationary seal ring 3 is engaged with an annular O-ring groove 31e formed on the outer periphery thereof. The inner peripheral surface 22b of the portion 22 is fitted and held so as to be movable in the axial direction. Further, in the case shown in FIG. 4, the seal case is interposed via an O-ring 32 in which the base end portion 31 of the stationary seal ring 3 is engaged with an annular O-ring groove 22 e formed in the inner peripheral portion of the seal case 2. The two spring retainer portions 22 are fitted and held so as to be movable in the axial direction. 3, the balance diameter D0 is the diameter of the inner peripheral surface 22b of the spring retainer portion 22 with which the outer peripheral surface of the O-ring 32 comes into contact. In the one shown in FIG. 4, the inner peripheral surface of the O-ring 32 is It is the diameter of the outer peripheral surface 31a of the base end part 31 of the stationary sealing ring 3 which contacts, and all are set so that it may become D1 <= D0 <= D2 (optimally D0 = (D1 + D2) / 2). 3 and 4 have the same structure as that of the outside-type mechanical seal M shown in FIGS. 1 and 2 except for the points described above, the same parts are shown in FIGS. 3 and 4. The same reference numerals as those shown in FIG. 1 and FIG.

DESCRIPTION OF SYMBOLS 1 Shaft seal part housing 1a End face of shaft seal part housing 2 Seal case 3 Stationary sealing ring 3a Stationary side sealing end surface 4 Rotating shaft 5 Fixed ring 6 Rotating sealing ring 6a Rotating side sealing end surface 7 Spring member 8 Flushing liquid passage 8a Flushing liquid 9 Quenching liquid passage 9a Quenching liquid 10 Space 11 Clearance passage 12 Set claw 12a First engagement protrusion 12b Second engagement protrusion 13 Bolt 14 Connection portion 14a Annular recess 15 Inner circumferential space 21 Main body portion 22 Spring retainer portion 22a End face 22b Inner peripheral surface 22c Annular step portion 22d Drive pin 22e O-ring groove 23 Annular gap 24 Annular gasket 31 Base end portion of stationary seal ring 31a Outer peripheral surface of base end portion 31b Annular step portion 31c Inner peripheral surface 31d of base end portion Base end face of sealing ring 31e O-ring groove 32 O-ring 33 End portion of stationary seal ring 33a Inner peripheral surface of tip portion 34 Annular flange portion 34a Engaging recess 51 Fixing portion 52 Seal ring holding portion 53 O-ring 54 Set screw 55 Drive pin 61 Base end portion 62 O-ring 63 Engaging recess 64 Front end portion 81 Upstream side portion 82 Downstream side portion 82a Opening 91 Drain path A In-machine region B Out-of-machine region M Outside type mechanical seal S Relative rotational sliding contact portion

Claims (6)

A cylindrical seal case attached to the shaft seal housing of the rotary device, a rotary seal ring fixed to the rotary shaft of the rotary device passing through the seal case, and a shaft seal housing side of the rotary seal ring. A stationary seal ring held axially movable in the seal case, and a spring member that is loaded between the seal case and the stationary seal ring and urges the stationary seal ring into pressure contact with the rotary seal ring. And the in-machine region which is the inner peripheral side region of the relative rotational sliding contact portion and the outer peripheral region which is the outer peripheral side region thereof are shielded by the relative rotational sliding contact action of the sealing end surfaces which are the opposite end surfaces of both sealing rings. In the outside type mechanical seal configured to seal,
The base end portion of the stationary seal ring is fitted and held on the inner peripheral portion of the seal case via an O-ring so as to be movable in the axial direction, and the distal end surface of the stationary seal ring is configured as a sealed end surface having a minute width in the radial direction. And the inner peripheral surface of the distal end portion of the stationary seal ring is formed into a frustoconical surface gradually reducing in diameter from the inner peripheral edge of the sealed end surface to the inner peripheral surface of the proximal end portion,
The front end surface of the rotary seal ring is configured as a sealed end surface whose inner diameter is larger than the inner peripheral surface of the base end portion of the stationary seal ring, and the base end portion of the rotary seal ring is fitted to a fixed ring fixed to the rotary shaft. A cylindrical space portion that is closed with a stationary ring and opens in the direction of the stationary sealing ring is formed between the opposed peripheral surfaces of the rotating sealing ring and the front end portion of the rotating sealing ring.
A seal case, SQLDESC_BASE_TABLE_NAME This proximity to the proximal end face of the stationary seal ring forms a flushing fluid passage that opens to the flight area Thea,
An annular gap that opens inward is formed at the abutting portion between the seal case and the shaft seal housing, and an annular gasket that seals between the seal case and the shaft seal housing is formed on the outer peripheral side of the annular gap. with loading, flushing fluid passage in proximity to the proximal end face of the stationary seal ring on the inner peripheral portion of the annular gap, characterized in Oh isosamples is opened outside type mechanical seal.   The outside-type mechanical seal according to claim 1, wherein the rotary seal ring and the stationary seal ring are made of ceramics.   The outside type mechanical seal according to claim 1 or 2, wherein a radial width of a sealing end face of the stationary sealing ring is 1 mm or less.   The out diameter according to any one of claims 1 to 3, wherein the balance diameter D0 is set so that D1 ≤ D0 ≤ D2 with respect to the inner and outer diameters D1, D2 of the sealing end face of the stationary sealing ring. Side type mechanical seal. 5. The outside according to claim 1, wherein a quenching liquid passage that opens to an outside region in the vicinity of the relative rotational sliding contact portion of both sealing rings is formed in the seal case . Type mechanical seal. By engaging a set claw detachably attached to a stationary ring with a stationary side sealing element composed of a seal case and a member attached thereto, and a rotating side sealing element composed of a stationary ring and a rotational sealing ring, The outside-type mechanical seal according to any one of claims 1 to 5, wherein the outside-type mechanical seal is a cartridge-type mechanical seal configured to be temporarily connected to the same form as the use form of the mechanical seal. .

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