JP2013096568A - Mechanical seal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mechanical seal device for reducing abnormal wear, as well as leakage, while stably rotating an intermediate ring.SOLUTION: This mechanical seal device 10 seals a fluid to be sealed between a rotary shaft 12 and a casing 14 for covering the rotary shaft 12. This device 10 includes: the intermediate ring 20 held between a rotary sealing ring 22 and a resting sealing ring 18 along the axial direction of the rotary shaft 12, sliding with both the rotary sealing ring 22 and the resting sealing ring 18, and relatively rotatably arranged with respect to both the rotary sealing ring 22 and the resting sealing ring 18; and gears 66, 68, 70 and 72 connected to the intermediate ring 20 and forcibly rotating the intermediate ring 20 in the same direction as the rotary sealing ring 22 at a rotating speed α slower than a rotating speed β of the rotary sealing ring 22.

Description

  The present invention relates to a mechanical seal device, and more particularly to an improvement of a mechanical seal device using an intermediate ring.

  For example, in a shaft seal for a high-temperature and high-speed rotary pump represented by a shaft seal for a boiler supply pump (BFP), the mechanical seal device is cooled in order to prevent the temperature of the sealed fluid made of hot water from decreasing. A system that does not perform is required.

  However, when a system that does not cool the sliding surface is used in a mechanical seal device for high temperature, high pressure, and high rotation pumps, the amount of deformation due to temperature and pressure of the members constituting the sliding surface increases, and the sliding surface The situation of the contact surface is an edge-like contact, and there is a problem that leakage occurs. Further, the sliding surface fluid evaporates due to sliding heat generation, and solid contact occurs on the sliding surface, which may lead to abnormal wear or damage.

  As a conventional technique for solving such a problem, for example, an arrangement in which an intermediate ring is arranged between a rotary seal ring and a stationary seal ring in order to suppress deformation of a sliding surface is known ( For example, see Patent Document 1).

  As another conventional technique, a blade row is installed on the sliding surfaces of the intermediate ring, the rotary seal ring, and the stationary seal ring to reduce the sliding torque between the intermediate ring, the rotary seal ring, and the stationary seal ring. (For example, see Patent Document 2).

  However, in the prior art in which the intermediate ring is arranged between the rotary seal ring and the stationary seal ring, the intermediate ring cannot rotate with respect to the static seal ring or rotates at the same rotational speed as the rotary seal ring. Or have repeated these conditions. That is, with the conventional technique, it has been difficult to stably rotate the intermediate ring at, for example, about 1/2 of the rotational speed of the rotary seal ring.

  In addition, in the conventional technology in which the blade row is installed on the sliding surface, it is difficult to control the sliding torque for the intermediate ring, the stationary seal ring, and the rotary seal ring. The problem that it is difficult, and the problem that leakage occurs from the sliding surface.

  In addition, as shown in Patent Document 3, a structure in which a retaining ring with a blade-like groove is attached to the outer periphery of the intermediate ring and fluid is blown to the outer periphery of the retaining ring (a jetting fluid) to rotate the intermediate ring. Proposed. However, in such a structure, since the internal fluid pressurized by the rotation of the rotating body is used as the ejection fluid, the rotation speed of the intermediate ring (number of rotations per unit time) affects the pressure change of the internal fluid. To do. For this reason, it is difficult to stably rotate the intermediate ring, and the friction coefficient of the sliding surface is not stable.

Japanese Patent No. 4147216 Japanese Examined Patent Publication No. 61-58704 JP-A-9-229204

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a mechanical seal device that can stably rotate an intermediate ring, has less abnormal wear, and has less leakage. .

In order to achieve the above object, a mechanical seal device according to the present invention comprises:
A mechanical seal device for sealing a sealed fluid between a rotating shaft and a casing covering the rotating shaft,
A rotating seal ring that rotates integrally with the rotating shaft;
A stationary seal ring attached to the casing so as not to rotate relative to the casing;
It is sandwiched between the rotary seal ring and the stationary seal ring along the axial direction of the rotary shaft, and slides with both the rotary seal ring and the stationary seal ring. An intermediate ring arranged to be rotatable relative to
A mechanical rotation transmission mechanism connected to the intermediate ring and forcibly rotating the intermediate ring in the same direction as the rotary seal ring at a rotation speed lower than the rotation speed of the rotary seal ring.

  In the mechanical seal device according to the present invention, the intermediate ring is forcibly rotated in the same direction as the rotary seal ring at a rotation speed slower than the rotation speed of the rotary seal ring by the mechanical rotation transmission mechanism. Therefore, it is possible to avoid a state in which the intermediate ring cannot be rotated with respect to the stationary seal ring, and the intermediate ring can be stably and forcibly rotated at a predetermined rotation speed (α).

  The predetermined rotational speed (α) is smaller than the rotational speed (β) of the rotary seal ring, and the heat generated on the sliding surface between the intermediate ring and the stationary seal ring directly causes the rotary seal ring to It is smaller than the heat generated on the sliding surface when it comes into contact with the stationary seal ring.

  Therefore, even if the mechanical seal device of the present invention is used in an environment of high temperature, high pressure and / or high speed rotation, abnormal wear of the rotary seal ring, stationary seal ring and intermediate ring is reduced, and their durability Will improve. Furthermore, unlike the prior art, in the mechanical seal device of the present invention, it is not necessary to form blade rows on the sliding surfaces of the rotary seal ring, the intermediate ring, and the stationary seal ring, and the ejected fluid can be sprayed onto the slide surface. Because there is no leakage of the sealed fluid from the sliding surface.

  Preferably, the mechanical rotation transmission mechanism is a reduction mechanism that decelerates the number of rotations of the rotation shaft and transmits it to the intermediate ring. Another driving force that is not related to the rotation of the rotating shaft (for example, a rotational driving force of a motor or the like) may be transmitted to the intermediate ring via a mechanical rotation transmission mechanism. By using it, the intermediate ring can be forcibly rotated without requiring a separate power source.

  Preferably, the mechanical rotation transmission mechanism is a combination of at least two gears. A pulley or the like can be considered as the mechanical rotation transmission mechanism, but the structure of the apparatus is simplified by using a gear gear.

  Preferably, the intermediate ring is fixed to the outer sleeve, the outer sleeve is rotatably attached to the inner sleeve via a bearing, and the inner sleeve is connected to the rotating shaft. It is fixed to. By adopting such a configuration, it becomes easy to rotate the intermediate ring independently at a predetermined rotational speed with respect to the rotation shaft, the rotary sealing ring, and the stationary sealing ring.

Preferably, a drive side gear gear is fixed to the inner peripheral side sleeve,
A passive gear is fixed to the outer sleeve,
The drive side gear gear and the passive side gear gear are connected by other gear gears,
These gear gears constitute the mechanical rotation transmission mechanism. By adopting such a configuration, the intermediate ring can be forcibly rotated at a predetermined rotational speed (α) using the rotational force of the rotating shaft.

FIG. 1 is a schematic longitudinal sectional view showing an upper half of a mechanical seal device according to an embodiment of the present invention. FIG. 2 is a schematic longitudinal sectional view showing a lower half of the mechanical seal device shown in FIG. 1, and is a longitudinal section different from FIG. FIG. 3 is an enlarged cross-sectional view of a main part of the mechanical seal device shown in FIG.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
The mechanical seal device 10 according to one embodiment of the present invention shown in FIGS. 1 to 3 is used, for example, as a shaft seal for a boiler feed pump (BFP), but is not limited to a boiler feed pump, and other high temperature and high pressure. And / or as a shaft seal for a high-speed rotating device.

  The mechanical seal device 10 prevents the sealed fluid that flows through the internal gap 30 between the rotary shaft 12 that rotates about the shaft center Z and the casing 14 such as a pump from leaking to the outside 31 of the casing. And is attached to the inside of the seal cover 16.

  The seal cover 16 is detachably attached to the shaft end portion of the casing 14 via the flange cover 15, and their attachment surfaces are sealed by O-rings 24a to 24c. The seal cover 16 constitutes a part of the casing 14 including the flange cover 15, and may be formed integrally with the casing 14 including the flange cover 15. However, in order to facilitate maintenance of the mechanical seal device 10, the seal cover 16 is preferably detachably fixed to the casing 14 with or without the flange cover 15.

Inside the seal cover 16, a rotary sealing ring 22, an intermediate ring 20 and a stationary sealing ring 18 are arranged in this order along the rotary shaft 12 from the internal gap 30 toward the casing exterior 31. In the present embodiment, the material of the stationary seal ring 18, the intermediate ring 20, and the rotary seal ring 22 is not particularly limited, and is made of, for example, SiC, C, SiN, Al ₂ O ₃ , zirconia, and the like. The intermediate ring 20 and the rotary seal ring 22 may all be made of the same material, or may be different. Preferably, the stationary seal ring 18 and the rotary seal ring 22 are made of a material softer than the intermediate ring 20.

  As shown in FIG. 3, the tip sliding surface 18 a formed at the shaft end (left shaft end) on the intermediate ring side in the stationary seal ring 18 rotates and slides on the first sliding surface 20 a of the intermediate ring 20. It is like that. The second sliding surface 20b opposite to the first sliding surface 20a of the intermediate ring 20 is a tip sliding surface 22a formed at the shaft end (right shaft end) on the intermediate ring side of the rotary seal ring 22. It is designed to rotate and slide.

  On the outer peripheral side of the tip sliding surface 18a in the stationary seal ring 18, an outward projection 18b is formed. The outer protrusion 18 b is in contact with the tip end of the spring 32 as an elastic member in the axial direction, and the rear end of the spring 32 is held in a spring holding hole formed in the seal cover 16. The stationary sealing ring 18 is pressed in the axial direction by the elastic force of the spring 32, and the pressing force is transmitted from the stationary sealing ring 18 to the intermediate ring 20 and the rotary sealing ring 22, and each of these sliding surfaces 18 a, 20 a and 20 b. , 22a is ensured.

  The springs 32 are arranged at a plurality of positions along the circumferential direction. A base end portion of a detent pin 34 shown in FIG. 2 is fixed to the seal cover 16 between the springs 32 along the circumferential direction. The distal end portion of the detent pin 34 engages with a detent groove or hole formed in the outward projection 18 b of the stationary seal ring 18, so that the stationary seal ring 18 is in contact with the seal cover 16. It is mounted so that it can move in the axial direction but cannot be rotated relative to it. An O-ring 26 is attached between the stationary seal ring 18 and the seal cover 16 to prevent the sealed fluid from leaking between them.

  The rotary seal ring 22 is attached to the rotary shaft 12 so as to rotate integrally with the rotary shaft 12. Specifically, it is attached as follows. As shown in FIGS. 1-3, the 1st sleeve collar 44a is fixed to the rotating shaft 12 with the 1st set screw 46a. The inner sleeve 40a is fixed to the rotating shaft 12 by the first sleeve collar 44a, and the inner sleeve 40a rotates together with the rotating shaft 12.

  On the outer periphery of the inner peripheral sleeve 40a, an outer peripheral sleeve 40b is rotatably mounted independently of the inner peripheral sleeve 40a via a bearing 41 constituted by a needle bearing or the like.

  The inner end of the intermediate ring 20 is fixed to one shaft end of the outer sleeve 40b so as not to rotate relative to the outer sleeve 40b. The intermediate ring 20 is configured to be rotatable around the rotary shaft 12 together with the outer sleeve 40b. It is. A passive gear gear 72, which will be described later, is fixed to the other shaft end of the outer sleeve 40b, and is rotatable integrally with the outer sleeve 40b.

  A bearing protection ring 43 and an auxiliary sleeve 40c are arranged in this order along the axial direction at the shaft end on the intermediate ring 20 side of the inner circumferential sleeve 40a. The bearing protection ring 43 is fixed to the shaft end of the inner sleeve 40 a with a bolt or the like, and prevents the sealed fluid leaking into the inner space 56 of the rotary sealing ring 22 from entering the bearing 41. ing.

  The auxiliary sleeve 40c is fixed to the rotating shaft 12 by the second sleeve collar 44b and rotates integrally with the rotating shaft 12. An O-ring 42 is mounted between the auxiliary sleeve 40c and the rotary shaft 12, and the sealed fluid is prevented from leaking from between these.

  The second sleeve collar 44b is fixed to the rotary shaft 12 together with the auxiliary sleeve 40c by a second set screw 46b or the like, and rotates together with the rotary shaft 12. An O-ring 48 is mounted between the second sleeve collar 44b and the auxiliary sleeve 40c, and the sealed fluid is prevented from leaking into the inner space 56 from between these.

  As shown in FIG. 3, an outward convex portion 22 b is formed on the outer peripheral side of the tip sliding surface 22 a in the rotary sealing ring 22. As shown in FIG. 2, the axially forward end of a spring 52 as an elastic member is in contact with the outward convex portion 22b, and the rear end of the spring 52 is a spring holding member formed on the second sleeve collar 44b. Retained in the hole. The elastic force of the spring 52 is preferably weaker than the elastic force of the spring 32 described above. For example, 1/4 to 1/8 of the elastic force of the spring 32 is preferable. Alternatively, the spring 52 is not necessarily provided in the present embodiment.

  The springs 52 shown in FIG. 2 are arranged at a plurality of positions, for example, along the circumferential direction. Between the springs 52 along the circumferential direction, the base end portion of the detent pin 54 shown in FIG. 1 is fixed to the second sleeve collar 44b. The distal end portion of the detent pin 54 engages with a detent groove or hole formed in the outward convex portion 22b of the rotary seal ring 22, so that the rotary seal ring 22 is in contact with the second sleeve collar 44b. In addition, it is attached so as to be movable in the axial direction and not to be relatively rotatable. An O-ring 50 is attached between the rotary seal ring 22 and the sleeve collar 44 to prevent the sealed fluid from leaking into the inner space 56 of the rotary seal ring 22.

  As shown in FIGS. 1 and 2, a gear box cover 60 is detachably attached to a shaft end of the seal cover 16 opposite to the casing 14. The gear box cover 60 is detachably attached to the flange cover 15 with bolts 17, and the flange cover 15 is detachably attached to the casing 14 with bolts 19.

  In the internal space 61 of the gear box cover 60, gear gears 66, 68, 70 and 72 as mechanical rotation transmission mechanisms are arranged. The intermediate gear gears 66 and 70 are fixed to a gear rotation shaft 62 that is rotatably mounted on an end wall 60 a of the gear box cover 60 via a bearing 64 such as a ball bearing, and together with the gear rotation shaft 62. It can be rotated.

  The gear rotation shaft 62 is parallel to the axis Z of the rotation shaft 12, and together with the intermediate gear gears 66 and 70, the end wall of the gear box cover 60 at a plurality of positions (for example, 2 to 6 locations) around the rotation shaft 12. It is rotatably mounted on 60a. One intermediate gear gear 66 having a relatively large outer diameter meshes with a drive side gear gear 68 fixed to the inner circumferential sleeve 40 a so as not to rotate. As the rotary shaft 12 rotates, the drive side gear gear 68 is engaged. At the same time, the intermediate gear 66 is rotated.

  Since the intermediate gear gear 66 is fixed to the gear rotation shaft 62, the rotational force of the intermediate gear gear 66 is transmitted to the intermediate gear gear 70 having a relatively small outer diameter, and the intermediate gear gear 70 is simultaneously rotated. . The intermediate gear gear 70 meshes with the aforementioned passive gear gear 72, and the rotational force of the intermediate gear gear 70 is transmitted to the passive gear gear 72, causing the passive gear gear 72 to rotate with the outer sleeve 40b. . Since the intermediate ring 20 is fixed to the outer sleeve 40b, the intermediate ring 20 is forcibly rotated around the axis Z when the outer sleeve 40b rotates.

  These gear gears 66, 68, 70, 72 constitute a reduction mechanism, and by appropriately setting the number of teeth and the outer diameter of these gear gears 66, 68, 70, 72, The intermediate ring 20 can be rotated in the same direction as the rotation direction of the rotary shaft 12 at a predetermined rotation speed (α) smaller than the rotation speed (β).

  The predetermined rotation speed (α) is a speed smaller than the rotation speed of the rotary shaft 12 and the rotation speed (β) of the rotary seal ring 22, and is not particularly limited, but is a ratio to the rotation speed (β) of the rotary seal ring 22. (Α / β) is determined to be less than 1, preferably ¼ to ¾, particularly preferably ½ ± 1/10.

  That is, in the mechanical seal device 10 according to the present embodiment, the intermediate ring 20 is forcibly set to a predetermined rotational speed (α by appropriately setting the number of teeth and the outer diameter of the gear gears 66, 68, 70, 72. ). Therefore, it is possible to effectively avoid a state in which the intermediate ring 20 cannot rotate with respect to the stationary sealing ring 18, and the intermediate ring 20 can be stably and forcibly rotated at a predetermined rotational speed (α). Is possible.

  The predetermined rotational speed (α) is lower than the rotational speed (β) of the rotary seal ring 22, and heat generated on the sliding surface between the intermediate ring 20 and the stationary seal ring 18 is generated by the rotary seal ring. When the 22 is directly brought into contact with the stationary seal ring 18, the heat generated on the sliding surface is smaller than that generated on the sliding surface. This is because the insertion of the intermediate ring 20 increases the number of sliding surfaces to two. By generating a relative speed between the two sliding surfaces, heat is generated on each sliding surface. This is because the amount of heat generated on each sliding surface can be made smaller than the amount of heat generated when the rotary sealing ring 22 is brought into direct contact with the stationary sealing ring 18 in order to disperse the heat generation. For example, if α / β is about ½, the heat generated on the sliding surface between the intermediate ring 20 and the stationary seal ring 18 may cause the rotary seal ring 22 to contact the stationary seal ring 18 directly. Compared to the heat generated on the sliding surface on the sliding surface, it is about ½.

  Therefore, in the mechanical seal device 10 of the present embodiment, abnormal wear of the rotary seal ring 22, the stationary seal ring 18, and the intermediate ring 20 is reduced even when used in an environment of high temperature, high pressure and / or high speed. , These durability will be improved. Furthermore, in the mechanical seal device 10 of the present embodiment, unlike the prior art, it is not necessary to form blade rows on the sliding surfaces of the rotary seal ring 22, the intermediate ring 20, and the stationary seal ring 18, and the ejected fluid is slid. Since there is no spray on the surface, there is little leakage of the sealed fluid from the sliding surface.

  Furthermore, in this embodiment, the intermediate ring 20 is fixed to the outer sleeve 40b, and the outer sleeve 40b is rotatably attached to the inner sleeve 40a via the bearing 41. 40 a is fixed to the rotary shaft 12. By adopting such a configuration, the intermediate ring 20 can be forcibly rotated independently at a predetermined rotational speed α with respect to the rotary shaft 12, the rotary seal ring 22, and the stationary seal ring 18. It becomes easy.

  Further, in the present embodiment, the drive side gear gear 68 is fixed to the inner peripheral side sleeve 40a, and the passive side gear gear 72 is fixed to the outer peripheral side sleeve 40b. A side gear gear 72 is connected by other intermediate gear gears 66 and 70. By adopting such a configuration, the intermediate ring 20 can be forcibly rotated at a predetermined rotational speed (α) using the rotational force of the rotary shaft 12.

  The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention.

  For example, without providing the intermediate ring 66 and the drive gear gear 68, the gear rotation shaft 62 may be independently rotated at a predetermined rotation speed α by other drive rotation means (for example, rotation means such as a motor). .

  In the above-described embodiment, the mechanical rotation transmission mechanism is a combination of at least two or more gear gears. However, a pulley or the like may be employed as the mechanical rotation transmission mechanism. However, the structure of the apparatus is simplified by using the gear gear as in the above-described embodiment.

  Further, in the above-described embodiment shown in FIGS. 1 to 3, a drain hole 20 c is provided at an inner position of the sliding surfaces 18 a, 20 a and 22 a, 22 b (see FIG. 3) in the intermediate ring 20, and the rotary sealing ring 22 is provided. The sealed fluid that has leaked into the inner space 56 may be discharged toward the inner space 61 of the gear box cover 60. Further, a lubricating oil supply chamber for lubricating the gear gears 66, 68, 70, 72 and the bearings 41 and 64 may be provided in the internal space 61 of the gear box cover 60.

  Further, in the embodiment described above, the inside type mechanical seal device in which the sealed fluid is located on the outer peripheral side of the sealing rings 18 and 22 has been described. However, the structure of the present invention is sealed on the inner peripheral side of the sealing rings 18 and 22. The present invention can also be applied to an outside type mechanical seal device in which a fluid is located.

DESCRIPTION OF SYMBOLS 10 ... Mechanical seal apparatus 12 ... Rotating shaft 14 ... Casing 15 ... Flange cover 16 ... Seal cover 18 ... Static sealing ring 18a ... Sliding surface 20 ... Intermediate ring 20a, 20b ... Sliding surface 20c ... Drain hole 22 ... Rotating sealing ring 22a ... Sliding surfaces 32, 52 ... Spring 40a ... Inner peripheral sleeve 40b ... Outer peripheral sleeve 41 ... Bearing 60 ... Gearbox cover 62 ... Gear rotating shaft 64 ... Bearing 66, 70 ... Intermediate gear gear 68 ... Drive side gear gear 72 ... Passive gear

Claims (5)

A mechanical seal device for sealing a sealed fluid between a rotating shaft and a casing covering the rotating shaft,
A rotating seal ring that rotates integrally with the rotating shaft;
A stationary seal ring attached to the casing so as not to rotate relative to the casing;
It is sandwiched between the rotary seal ring and the stationary seal ring along the axial direction of the rotary shaft, and slides with both the rotary seal ring and the stationary seal ring. An intermediate ring arranged to be rotatable relative to
A mechanical seal transmission device connected to the intermediate ring and having a mechanical rotation transmission mechanism that rotates the intermediate ring in the same direction as the rotary seal ring at a rotation speed lower than the rotation speed of the rotary seal ring.   2. The mechanical seal device according to claim 1, wherein the mechanical rotation transmission mechanism is a reduction mechanism that reduces the number of rotations of the rotation shaft and transmits it to the intermediate ring.   The mechanical seal device according to claim 1 or 2, wherein the mechanical rotation transmission mechanism is a combination of at least two gears.   The intermediate ring is fixed to the outer sleeve, the outer sleeve is rotatably attached to the inner sleeve via a bearing, and the inner sleeve is fixed to the rotating shaft. The mechanical seal device according to any one of claims 1 to 3. A driving gear is fixed to the inner circumferential sleeve,
A passive gear is fixed to the outer sleeve,
The drive side gear gear and the passive side gear gear are connected by other gear gears,
The mechanical seal device according to claim 4, wherein these gear gears constitute the mechanical rotation transmission mechanism.

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