JP4797097B2 - Outside type mechanical seal - Google Patents

Description

  The present invention relates to a mechanical seal installed in a rotary device such as a pump and a stirrer, and more particularly to an outside type mechanical seal.

  The mechanical seal is roughly classified into an inside type and an outside type. The inside-type mechanical seal is a structure in which a fluid to be sealed (sealed fluid) tries to enter from the outer diameter side to the inner diameter side of the seal portion (sliding surface), and is disclosed in Patent Document 1 as an example. The seal is known. This is because the leakage direction is in a direction opposite to the centrifugal force of the seal portion, and therefore the sealing condition is extremely advantageous as compared with the outside type described later, and it is the most frequently used mechanical seal.

  On the other hand, an outside-type mechanical seal is one that seals in the opposite direction to the above-mentioned inside-type seal, and has a structure in which the fluid to be sealed tries to enter from the inner diameter side to the outer diameter side of the seal portion. As an example, a seal disclosed in Patent Document 2 is known. Since the leakage direction is the same as the centrifugal force of the seal portion, the sealing condition is disadvantageous compared to the inside type. However, most of the components of the mechanical seal are outside the staffin box, and there are few parts in contact with the fluid to be sealed, making it suitable for sealing highly corrosive fluids without using expensive materials, as well as maintenance and inspection. Has the advantage of being easy.

  Consider cooling of a seal portion in a conventional outside type mechanical seal. FIG. 5 shows a structure in which the rotary seal ring 2 is pressed and urged against the stationary seal ring 4 by the elastic mechanism 5, that is, a rotary outside type mechanical seal Bo. In this case, even if the sealing portion S is cooled by the flushing fluid f, the flushing fluid f mainly flows only on the back side of the stationary seal ring 4 as shown by a thick arrow in FIG. It cannot be expected to flow to the seal portion S through a gap between the ring 4 and the rotary shaft 1, that is, an extremely narrow annular space (not shown). Accordingly, the cooling by the flushing fluid f is not very effective, and heat generated by sliding of the seal portion S raises the fluid temperature in the vicinity thereof, resulting in insufficient cooling, and the seal portion S is poorly lubricated, rough, and easily leaks. There is a risk of inconvenience.

  Therefore, when there is a concern about insufficient cooling, a separate cooling fluid supply system (quenching) is required from the outside (outside of the atmosphere and the atmosphere side) of the seal portion. In this case, a gland packing is used as an auxiliary seal. It is also necessary to provide an oil seal or the like. Furthermore, in order to reduce the wear of the sliding part of the auxiliary seal, a hardening process such as a ceramic coating of the metal part may be required, so that the cooling system as a whole is intricate in structure and cost. In addition, the number of maintenance points and frequency increases.

  FIG. 6 shows a conventional example of a structure in which the stationary seal ring 4 is pressed and urged against the rotary seal ring 2 by the elastic mechanism 25, that is, a stationary outside mechanical seal Bi. Even in this structure, the flushing fluid f flows through the narrow annular space K between the holder 23 and the stationary sealing ring 4 and the rotating shaft 1 and flows well as in the rotary type described above. It cannot be expected, and it is difficult to cool the seal portion S with the flanking fluid f. Therefore, a trouble due to insufficient cooling of the seal portion S is likely to occur. Therefore, quenching is necessary even in this case, and the above disadvantages (complication of structure, cost increase, etc.) are caused by providing an external cooling system and an auxiliary seal such as a gland packing and an oil seal.

  In addition, the code | symbol of each part in the conventional rotary outside type mechanical seal Bo shown in FIG. 5 uses the code | symbol of the rotary outside type mechanical seal A of Example 1 shown in FIG. The reference numerals of the respective parts of the stationary outside mechanical seal Bi shown in FIG. 3 are the same as those of the stationary outside mechanical seal A of the second embodiment shown in FIGS.

JP 2006-250306 A JP-A-11-336912

  The object of the present invention is to improve the outflow so that the structure can be simplified and the cost can be reduced without requiring quenching by further cooling the seal portion with the flushing fluid by further structural improvements. It is in providing a side-type mechanical seal.

The invention according to claim 1 is non-rotatable with respect to the rotary shaft 1 and is not rotatable with respect to the seal housing 3 and the rotary seal ring 2 supported so as to be movable in the direction of the axis P of the rotary shaft 1. A stationary seal ring 4 supported on the stationary seal ring 4 and an elastic mechanism 5 for pressing the rotary seal ring 2 against the stationary seal ring 4 to form a seal portion S, and the seal portion S of the fluid to be sealed e. In the outside-type mechanical seal configured to seal the movement from the inside diameter to the outside diameter,
A spring retainer 8 that is externally supported in a sealed state on the rotating shaft 1 is provided, and the rotating seal ring 2 is supported by the spring retainer 8 in a sealed state via the elastic mechanism 5. Is not rotatable with respect to the rotary shaft 1 and is supported so as to be movable in the axial direction of the rotary shaft,
A baffle cylinder 7 extending from the spring retainer 8 to an annular space K between the stationary seal ring 4 and the rotating shaft 1 is provided, and an inner annular space between the rotating shaft 1 and the baffle cylinder 7 is provided. A short circuit is formed in the baffle cylinder 7 at a position corresponding to the seal portion S in the axial center P direction, with the portion si, the outer baffle cylinder 7 between the baffle cylinder 7 and the stationary seal ring 4. It is characterized by being configured to communicate with each other through a path 15.

According to the second aspect of the present invention, the rotary seal ring 2 that rotates integrally with the rotary shaft 1 and the stationary member that is non-rotatable with respect to the seal housing 3 and that is supported so as to be movable in the axis P direction of the rotary shaft 1. It has a sealing ring 4 and an elastic mechanism 25 for pressing the stationary sealing ring 4 against the rotary sealing ring 2 to form the seal portion S, and the diameter of the fluid to be sealed e from the inside of the diameter of the seal portion S is increased. In an outside-type mechanical seal configured to seal outward movement,
The rotary shaft 1 is provided with a drive ring 28 fitted and supported in a sealed state, and the rotary seal ring 2 is supported on the rotary shaft 1 by allowing the drive ring 28 to support the rotary seal ring 2 in a sealed state. It is fitted in an integral rotation state,
A baffle cylinder 32 extending from the drive ring 28 to an annular space K between the stationary seal ring 4 and the rotary shaft 1 is provided, and an inner annular space between the rotary shaft 1 and the baffle cylinder 32 is provided. A short circuit is formed in the baffle cylinder 32 at a position corresponding to the seal portion S in the axial center P direction, with the part si, the baffle cylinder 32 and the outer annular space so between the stationary seal ring 4. It is configured to be communicated by a path 33.

  The invention according to claim 3 is the outside type mechanical seal according to claim 1 or 2, wherein the flushing fluid f supplied to the annular space K is transferred from the inner annular space si to the short-circuit path 15, The short circuit is configured such that the flushing fluid f that flows from the short-circuit paths 15 and 33 to the outer annular space portion so is directed to the seal portion S. The direction of the roads 15 and 33 is set.

  The invention according to claim 4 is the outside type mechanical seal according to claim 1 or 2, wherein the flushing fluid f supplied to the annular space K is supplied from the inner annular space si to the short-circuit path 15, The guide portion g that guides the flushing fluid f that flows out from the short-circuit paths 15 and 33 to the outer annular space portion so to the seal portion S is configured to flow to the outer annular space portion so through 33. The seal ring 2 or the stationary seal ring 4 is formed.

  The invention according to claim 5 is the outside type mechanical seal according to any one of claims 1 to 4, wherein the short-circuit paths 15 and 33 are holes that penetrate the baffle cylinders 7 and 32 in the radial direction. It is constituted by a plurality.

  According to the first aspect of the present invention, the baffle tube is provided between the stationary stationary ring having a fixed position and the rotating shaft to divide the annular space portion into the inner annular space portion and the outer annular space portion, and each of these space portions. By providing a short circuit that communicates at a position corresponding to the seal portion in the axial direction of the shaft, the flushing fluid circulates and flows well in the radially inner portion of the seal portion, thereby cooling and lubricating the seal portion. It will be clearly promoted compared to the past. That is, the annular space portion that has conventionally been a single space is provided with an outward path and a return path, and the circulation efficiency of the fluid is clearly improved. As a result, in the rotary outside mechanical seal that presses the rotary seal ring against the stationary seal ring, the seal part can be sufficiently cooled by the flushing fluid, and the structure is simplified and the cost is not required without quenching. I was able to improve it so that it could go down.

  According to the invention of claim 2, a baffle tube is provided between the movable stationary sealing ring and the rotary shaft to divide the annular space portion into the inner annular space portion and the outer annular space portion, and each of these space portions. By providing a short circuit that communicates at a position corresponding to the seal portion in the axial direction of the shaft, the flushing fluid circulates and flows well in the radially inner portion of the seal portion, thereby cooling and lubricating the seal portion. It will be clearly promoted compared to the past. That is, the annular space portion that has conventionally been a single space is provided with an outward path and a return path, and the circulation efficiency of the fluid is clearly improved. As a result, in the static outside mechanical seal that presses the stationary seal ring against the rotating seal ring, the seal part can be sufficiently cooled by the flushing fluid, and the structure is simplified and the cost is not required without quenching. I was able to improve it so that it could go down.

  According to the invention of claim 3, since the direction of the short circuit is set so that the flushing fluid exiting from the short circuit to the outer annular space is directed to the seal part, the flushing fluid is further supplied to the seal part. As a result, the cooling and lubrication of the seal portion is promoted more smoothly, and there is an advantage that any of the effects according to the invention of claim 1 or 2 is enhanced.

  According to the invention of claim 4, since the guide part for guiding the flushing fluid that exits from the short-circuit path to the outer annular space part to the seal part is formed in the rotary seal ring or the stationary seal ring, the flushing fluid is further sealed. Therefore, cooling and lubrication of the seal portion are promoted more effectively, and there is an advantage that any one of the effects according to the invention of claim 1 or 2 is enhanced.

  According to the invention of claim 5, since the short circuit is formed by a plurality of short holes, the flow rate of the flushing fluid from the inner annular space toward the outer annular space can be increased. Therefore, cooling and lubrication of the seal portion can be promoted also by devising the shape of the short-circuit path, and there is an advantage that any one of the effects according to the inventions of claims 1 to 4 is enhanced.

Sectional drawing which shows the structure of a rotary outside type mechanical seal (Example 1) Fig. 1 is an enlarged cross-sectional view near the seal part Sectional drawing which shows the structure of a stationary outside type mechanical seal (Example 2) Fig. 3 is an enlarged cross-sectional view near the seal part Sectional view showing a conventional rotary outside mechanical seal Sectional view showing a conventional static outside type mechanical seal

  Embodiments of an outside type mechanical seal according to the present invention will be described below with reference to the drawings. The first embodiment is a rotary type, and the second embodiment describes a stationary outside type mechanical seal.

[Example 1]
FIG. 1 shows an outside type mechanical seal A according to the first embodiment. This is a rotary seal ring 2 that is non-rotatable with respect to the rotary shaft 1 and is supported so as to be movable in the direction of the axis P of the rotary shaft 1, and a stationary seal that is non-rotatably supported with respect to the seal housing 3. The ring 4 and the elastic mechanism 5 for forming the seal portion S by pressing the rotary seal ring 2 against the stationary seal ring 4 and moving the seal target fluid e from the inside diameter to the outside diameter. It is comprised in the rotational outside type mechanical seal A which seals.

  On the inner peripheral surface side of the seal housing 3 disposed so as to surround the rotary shaft 1, a stationary sealing ring 4 that forms an annular shape when viewed in the direction of the axis P is sealed using a pair of O-rings 6, 6. It is fitted in a state that is incapable of moving in the direction of the axis P and in which the rotation around the axis P is restricted. The stationary seal ring 4 includes a seal surface 4a orthogonal to the axis P to contact the rotary seal ring 2, an inner peripheral surface 4b parallel to the axis P, a tapered inner peripheral surface 4c inclined with respect to the axis P, and the like. And are arranged outside the diameter of the rotary shaft 1 with a gap.

  The rotary shaft 1 is equipped with a spring retainer 8 that is externally supported in a sealed state, and the rotary seal ring 2 is supported by the spring retainer 8 via the elastic mechanism 5 in a sealed state. 1 is supported so as to be non-rotatable and movable in the direction of the axis P. The spring retainer 8 is fitted on the rotary shaft 1 with a seal through the O-ring 9, and is fixedly supported so as to rotate integrally with the rotary shaft 1 by tightening the shaft bolt 10 in a direction perpendicular to the axis P.

  On the outer peripheral surface 8a of the spring retainer 8 is relatively unrotatable about the axis P by the screw pin 11, and the side where the stationary seal ring 4 is present by a plurality of coil springs (an example of an elastic mechanism) (see FIG. 1 is fitted on the outer side of the drive collar 12 which is elastically biased. The rotary seal ring 2 is fitted in the drive collar 12 so as to be relatively unrotatable about the axis P by a torque pin 13 screwed on the drive collar 12. The stationary seal ring 2 and the spring retainer 8 are O-rings 14. It is sealed. Therefore, the rotary seal ring 2 is configured to be pressed and urged against the stationary seal ring 4 by the plurality of coil springs 5 while rotating integrally with the rotary shaft 1.

  By the plurality of coil springs 5, the seal surface 2 a of the rotary seal ring 2 and the seal surface 4 a of the stationary seal ring 4 are brought into contact with each other in the direction of the axis P and pressed to form a seal portion S. The outside type mechanical seal A having the annular seal portion S is configured to be able to seal the process side where the sealing target liquid e exists and the atmosphere side which is the outside of the housing 3. In FIG. 1, x is the axis of the coil spring 5 and the torque pin 13, and y is the axis of the screw pin 11.

  As shown in FIG. 1, the spring retainer 8 has a baffle cylinder 7 extending from an end of the stationary seal ring existing side to an annular space K between the stationary seal ring 4 and the rotary shaft 1. It is integrally formed. Thus, the inner annular space si between the rotary shaft 1 and the baffle cylinder 7 and the outer annular space so between the baffle cylinder 7 and the stationary seal ring 4 correspond to the seal portion S in the direction of the axis P. It is comprised so that it may be connected by the some short circuit 15 formed in the baffle cylinder 7 in the position to perform. The short circuit 15 is configured by a plurality of holes penetrating the baffle cylinder 7 in the radial direction.

  Since the inner diameter of the seal surface 4a of the stationary seal ring 4 is slightly smaller than the inner diameter of the seal surface 2a of the rotary seal ring 2, the flushing liquid (an example of the flushing fluid) f is effectively applied from the inner side to the seal portion S. In order to extend, it is preferable to supply by an oblique path from the position slightly closer to the rotary seal ring side to the contact portion of each seal surface 4a, 2a than the angle orthogonal to the axis P. For this purpose, the direction of the axis 15a of the short circuit 15 is inclined so as to be closer to the stationary seal ring existence side (the right side in FIG. 1) toward the outer side of the diameter. In this way, the flushing liquid f released from the short circuit 15 is sufficiently supplied to the inner diameter side end of the seal portion S, and cooling and lubrication can be effectively performed.

  That is, the flushing liquid f supplied from the supply path 16 formed in the housing 3 enters the inner annular space si from the annular inlet 17 as shown by the thick arrow in FIG. It enters the inner back end portion of the outer annular space so through the short-circuit path 15 located at the position. At that time, since the short-circuit path 15 is an inclined hole with an angle, for example, as shown in FIG. 2, when exiting from a hole (not shown) having a direction orthogonal to the axis P (see arrow a by virtual line) ), The flushing liquid f can be more effectively supplied to the inner diameter side end of the seal portion S in the present invention that is inclined (see arrow B).

  That is, an annular inlet 17 that is a supply / discharge portion of the flushing liquid f is provided in the annular space portion (an example of the “space portion for fluid to be sealed”) K, more specifically, the inner annular space portion si, and supplied. The flushing liquid f is configured to flow from the inner annular space si to the outer annular space so through the short-circuit path 15, and the flushing liquid f exiting from the short-circuit path 15 to the outer annular space so is directed to the seal portion S. The direction of the short circuit 15 is set so that

  In this way, the baffle cylinder 7 is provided between the stationary seal ring 4 and the rotary shaft 1 to divide the annular space K into the inner annular space si and the outer annular space so, and each of the spaces si, By providing the short-circuit path 15 that communicates the inner back portions of the so, the flushing liquid f circulates and flows well in the radially inner portion of the seal portion S, and the cooling and lubricating action of the seal portion S is promoted. Will come to be. In the conventional structure having only the annular space portion, the annular space portion is located at the end of the space where the fluid to be sealed exists, and the flow of the flushing fluid is not so much. Since the action is difficult to be exhibited, the cooling performance and the lubrication performance of the seal portion S are greatly improved by the present invention.

  The flushing liquid f may be the sealing target fluid e itself, or may be a dedicated liquid that does not adversely affect the sealing target fluid e. Although not shown, a guide member is provided for guiding and guiding the flushing liquid f exiting the supply passage 16 to the annular inlet 17 so that the flushing liquid f flows more vigorously to the radially inner portion of the seal portion S. It is also good.

[Example 2]
As shown in FIG. 3, the outside-type mechanical seal A according to the second embodiment is not rotatable with respect to the rotary seal ring 2 that rotates integrally with the rotary shaft 1 and the seal housing 3, and the shaft center of the rotary shaft 1. A stationary seal ring 4 supported so as to be movable in the P direction; and an elastic mechanism 25 for pressing the stationary seal ring 4 against the rotary seal ring 2 to form the seal portion S, and sealing the fluid to be sealed e The portion S is configured to be stationary so as to seal the movement from the radially inner side to the radially outer side.

  A spring retainer 21 having a flat annular shape having a diameter larger than the dimension in the axis P direction is bolted to the end surface 3A in the axis P direction of the seal housing 3 in a sealed state via an O-ring 22. Yes. The spring retainer 21 has a relative rotation around the axis P by a shaft pin 24 to be screwed and a plurality of coil springs (an example of an elastic mechanism) 25 arranged in a posture along the axis P. The holder 23 is fitted in a state that is impossible and is pressed and urged toward the rotary seal ring in the direction of the axis P.

  Then, the stationary seal ring 4 is supported by fitting in the holder 23, so that the holder 23 is not rotatable with respect to the seal housing 3, and is supported so as to be movable in the direction of the axis P of the rotary shaft 1, and an elastic mechanism. The seal portion S is formed by pressing the stationary seal ring 4 against the rotary seal ring 2 by 5. Reference numeral 26 denotes an O-ring for sealing the spring retainer 21 and the holder 23.

  The rotary shaft 1 is provided with a drive ring 28 that is fitted and supported in a sealed state via an O-ring 27, and the rotation ring 2 is supported by the drive ring 28 in a sealed state by an O-ring 31. The sealing ring 2 is configured to be fitted to the rotary shaft 1 in an integrally rotated state. The drive ring 28 is fixedly supported on the rotary shaft 1 by tightening a shaft bolt 29, and the rotary seal ring 2 is fitted to the drive ring 28 via a torque pin 30 screwed to the drive ring 28.

  A baffle cylinder 32 extending from the drive ring 28 to the annular space K between the stationary seal ring 4 and the rotary shaft 1 is provided, and the inner annular space si and the baffle cylinder between the rotary shaft 1 and the baffle cylinder 32 are provided. 32 and the outer annular space so between the stationary seal ring 4 are communicated by a short circuit 33 formed in the baffle cylinder 32 at a position corresponding to the seal portion S in the axis P direction. The short-circuit path 33 is composed of a plurality of short-circuit holes 33 formed through the baffle cylinder 32. Thereby, as in the case of Example 1,

  As shown in FIG. 4, the inner diameter of the sealing surface 4a of the stationary sealing ring 4 is larger than that of the sealing surface 2a of the rotary sealing ring 2, and the bottom surface of the sealing surface 4a extends to the inside of the diameter. A curved base surface 4d (an example of a guide portion g) is formed. Accordingly, the flushing liquid f moving from the short-circuit hole 33, which is an inclined hole inclined so as to be closer to the stationary sealing ring side in the direction of the axis P in the direction of the axis P toward the outer diameter side, is partly a holder. Partly moves along the curved bottom surface 4d and is supplied to the inner diameter side end of the seal portion S. That is, the curved skirt surface 4d functions as a guide surface that guides the flushing liquid f exiting the short-circuit hole 33 to the seal portion S.

  Also in the stationary outside type mechanical seal A according to the second embodiment, the baffle cylinder 7 is provided between the stationary sealing ring 4 and the rotary shaft 1 so that the annular space portion K is replaced with the inner annular space portion si and the outer annular space portion so. The flushing liquid f circulates and flows well in the radially inner portion of the seal portion S by providing the short-circuit path 33 that divides the space portions si and so into the inner back portions thereof. The cooling and lubricating action of the seal portion S is promoted. In the conventional structure having only the annular space portion, the annular space portion is located at the end of the space where the fluid to be sealed exists, and the flow of the flushing fluid is not so much. Since the action is difficult to be exhibited, the cooling performance and the lubrication performance of the seal portion S are greatly improved by the present invention.

DESCRIPTION OF SYMBOLS 1 Rotating shaft 2 Rotating sealing ring 3 Seal housing 4 Stationary sealing ring 5 Elastic mechanism 7 Baffle cylinder 8 Spring retainer 15 Short circuit 25 Elastic mechanism 28 Drive ring 32 Baffle cylinder 33 Short circuit K Annular space P Shaft S Seal part e Seal Target fluid f Flushing fluid g Guide portion si Inner annular space portion so Outer annular space portion

Claims (5)

A rotary seal ring that is non-rotatable with respect to the rotary shaft and is supported so as to be movable in the axial direction of the rotary shaft; a stationary seal ring that is non-rotatably supported with respect to the seal housing; and the rotary seal ring And an elastic mechanism for forming a seal portion by pressing against the stationary seal ring, and configured to seal the movement of the seal target fluid from the radially inner side to the radially outer side of the seal portion Type mechanical seal,
A spring retainer that is externally supported in a sealed state on the rotary shaft is provided, and the rotary seal ring is supported by the spring retainer in a sealed state via the elastic mechanism, so that the rotary seal ring is supported with respect to the rotary shaft. And is supported so as to be movable in the axial direction of the rotary shaft,
A baffle tube extending from the spring retainer to an annular space between the stationary seal ring and the rotating shaft is provided, an inner annular space between the rotating shaft and the baffle tube, the baffle tube, and the An outside-type mechanical structure in which the outer annular space between the stationary seal ring and the stationary seal ring is communicated by a short circuit formed in the baffle cylinder at a position corresponding to the seal portion in the axial direction. sticker. A rotary seal ring that rotates integrally with the rotary shaft; a stationary seal ring that is non-rotatable with respect to the seal housing and that is supported so as to be movable in the axial direction of the rotary shaft; and An outside type mechanical seal configured to seal the movement of the seal target fluid from the inside diameter to the outside diameter of the seal part. And
A drive ring that is externally supported in a sealed state is provided on the rotary shaft, and the rotary seal ring is fitted to the rotary shaft in an integrally rotated state by supporting the rotary seal ring in a sealed state on the drive ring. As
A baffle tube extending from the drive ring to an annular space between the stationary seal ring and the rotating shaft is provided, an inner annular space between the rotating shaft and the baffle tube, the baffle tube, and the An outside-type mechanical structure in which the outer annular space between the stationary seal ring and the stationary seal ring is communicated by a short circuit formed in the baffle cylinder at a position corresponding to the seal portion in the axial direction. sticker.   The flushing fluid supplied to the annular space portion is configured to flow from the inner annular space portion to the outer annular space portion through the short-circuit path and from the short-circuit path to the outer annular space portion. The outside type mechanical seal according to claim 1 or 2, wherein a direction of the short-circuit path is set so that a fluid is directed toward the seal portion.   The flushing fluid supplied to the annular space portion is configured to flow from the inner annular space portion to the outer annular space portion through the short-circuit path and from the short-circuit path to the outer annular space portion. The outside type mechanical seal according to claim 1 or 2, wherein a guide portion for guiding fluid to the seal portion is formed on the rotary seal ring or the stationary seal ring.   The outside type mechanical seal according to any one of claims 1 to 3, wherein the short-circuit path is configured by a plurality of holes penetrating the baffle cylinder in a radial direction.

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