JP2015183790A - mechanical seal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mechanical seal capable of efficiently removing heat generated at a sliding part and restricting biting of sludge into the sliding surface.SOLUTION: This invention relates to a mechanical seal 10 for sealing around a rotating shaft S through a sliding contact between a rotating ring 22 fixed to the rotating shaft S and a stationary ring 36 connected to a machine side member 14 through which the rotating shaft passes. The mechanical seal comprises a cylindrical space 16 to be sealed where sealing fluid E is stored; a cylindrical shower retainer for dividing the space 16 into a radial inner segment 16a where the rotating ring and the stationary ring are arranged and a radial outer segment 16b; and a circulation device 26 for feeding the sealing fluid from one end side of the spaced to be sealed into the radial inner segment to cause the seal fluid to be circulated within the sealed space. The shower retainer has an opening part formed at the other end side of the sealed space and formed to guide the seal fluid fed from one end side into the radial inner space by the circulation device to the radial outer space at the other end side.

Description

  The present invention relates to a mechanical seal, and relates to a mechanical seal in which a sealing fluid circulates in a shaft seal portion (sealed space) in which a rotating ring and a stationary ring are arranged.

  A mechanical seal is widely used in various fields as a sealing device that performs sealing by bringing the end faces of a rotating ring and a stationary ring into sliding contact.

  In such a mechanical seal, a liquid (seal fluid) is accommodated in a sealed space in which the rotating ring and the stationary ring are arranged, and the heat generated by the sealing fluid on the sliding surface between the rotating ring and the stationary ring is stored. A so-called dead-end mechanical seal is known which has a configuration in which the sealing fluid removed and further heated by the heat generated on the sliding surface is cooled by the refrigerant in the jacket (pump jacket) disposed at the outer position. (Non-Patent Document 1).

  Such a dead-end mechanical seal has an advantage that the configuration is simple because no auxiliary equipment such as a flushing pipe or a cooler is required.

"Mechanical seal handbook" Japan Industrial Machinery Manufacturers Association revised third edition

  However, the dead-end type mechanical seal having the above-described configuration does not sufficiently remove the heat generated in the sliding portion depending on the use situation, and as a result, the temperature of the sliding portion rises and the sliding portion There was a problem that abnormal wear occurred on the surface.

  Furthermore, the sliding surface bites the sludge generated in the sealed space, and the sliding portion such as the sliding surface is damaged.

  The present invention has been made in view of the above points, and provides a mechanical seal that can efficiently remove heat generated in the sliding portion and suppress sludge biting into the sliding surface. The purpose is to do.

According to the present invention,
A mechanical seal that seals the periphery of the rotating shaft by sliding contact between a rotating ring fixed to the rotating shaft and a stationary ring connected to a body-side member through which the rotating shaft passes;
A sealed space which is a cylindrical shaft seal portion in which the rotating ring and the stationary ring are arranged and a sealing fluid is accommodated;
A cylindrical shape that divides the sealed space into a radially inner portion in which the rotating ring and the stationary ring are disposed, and a radially outer portion located radially outward of the radially inner portion. Shower retainer,
A circulation device that feeds the seal fluid into the radially inner portion from one end side of the sealed space and circulates the seal fluid in the sealed space;
The shower retainer has an opening formed on the other end side of the sealed space, and the sealing fluid fed from one end side to the radially inner space by the circulation device on the other end side in the radial direction. Configured to lead to the outer space,
A mechanical seal is provided.

  According to such a configuration, the sealing device first sends the seal fluid from the one end side of the sealed space to the radially inner portion in which the rotating ring and the stationary ring are arranged. After flowing through the vicinity of the sliding surface, the other part of the sealed space circulates through the opening of the shower retainer so that it flows out to the radially outer space, so that the sliding part is efficiently cooled. At the same time, sludge near the sliding portion is removed.

According to another preferred embodiment of the invention,
A pump jacket is formed at an outer position of the outer radial space of the airframe side member.

  According to such a configuration, the sealing fluid guided to the radially outward portion of the sealed space by the circulation device is efficiently cooled by releasing heat by heat conduction to the pump jacket.

According to another preferred embodiment of the invention,
The rotating ring is disposed at one end side position of the stationary ring in the radially inner space;
The mechanical seal further includes:
A biasing means disposed at the other end side position of the stationary ring in the radially inner space, and biasing the stationary ring toward the rotating ring;
The opening includes an opening provided on the other end side from the biasing means.

According to such a configuration,
The seal fluid fed into the radially inner space flows into the radially outer space through the opening of the shower retainer while accompanying the sludge existing in the vicinity of the urging means. Removed.

According to another preferred embodiment of the invention,
The biasing means is a metal bellows.

According to such a configuration,
Sludge is efficiently excluded from the vicinity of the metal bellows where sludge tends to accumulate.

According to another preferred embodiment of the invention,
The opening includes a through hole provided on one end side with respect to the biasing means.

According to such a configuration,
The seal fluid fed into the radially inner space flows into the radially outer space through the opening of the shower retainer while accompanying the sludge existing in the vicinity of the sliding surface. Accumulation is suppressed.

According to another preferred embodiment of the invention,
The circulation device is an axial flow circulation device connected to the rotating shaft.

According to such a configuration,
The seal fluid can be circulated with a simple configuration.

According to another preferred embodiment of the invention,
The mechanical seal is a dead end type mechanical seal in which the sealing fluid is not injected into the sealed space and the sealing fluid is not discharged from the sealed space.

  ADVANTAGE OF THE INVENTION According to this invention, while removing the heat | fever which generate | occur | produced in the sliding part efficiently, the mechanical seal which can suppress the biting of the sludge to a sliding surface is provided.

It is sectional drawing which shows the structure of the mechanical seal of 1st Embodiment of this invention. It is a perspective view which shows the structure of the shower retainer used for the mechanical seal of FIG.

  Hereinafter, a mechanical seal according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the configuration of the mechanical seal of the present embodiment.

  The mechanical seal 10 of this embodiment seals the periphery of a rotating shaft by sliding contact between a rotating ring fixed to the rotating shaft and a stationary ring connected to a machine body side member through which the rotating shaft passes. It is a mechanical seal.

  The mechanical seal 10 of the present embodiment has a substantially cylindrical shape with a wall thickness defined by a rotation shaft S such as a rotation shaft of a motor, a mechanical seal cover 12 and a stuffing box 14 constituting a stationary side member (housing). The shaft seal portion (sealed space) 16 is a space. The mechanical seal 10 according to the present embodiment is a so-called dead-end mechanical seal in which the sealed space 16 is filled in the sealed space 16.

  The mechanical seal 10 of the present embodiment includes a cylindrical sleeve 18 to which a rotation shaft S is connected and fixed. An annular flange 18a extending outward is provided in the vicinity of the end of one end (the left side in FIG. 1) that is the end of the sleeve 18 on the machine inner side. A rotary ring 22 is attached to the outer surface of the flange 18a by a bolt 24 via an annular retainer 20. With such a configuration, the rotating ring 22 rotates integrally with the rotating shaft S.

  On the other hand, a collar 30, which is an annular member, is connected and fixed to the inner side in the radial direction of the mechanical seal cover 12 disposed outside the stuffing box 14. An adapter 34 is disposed inside the collar 30 via a bellows 32, and a stationary ring 36 is attached to the inside of the adapter 34.

  Similar to the mechanical seal of the prior art, in the mechanical seal 10 of the present embodiment, the stationary ring 36 has a tip surface (inside surface) that is in sliding contact with a tip surface (outside surface) of the rotating ring 22, and a sealing surface. (Sliding surface) 38 is formed.

  The bellows 32 is formed by aligning a plurality of metal diaphragms formed in a corrugated ring shape by punching or the like and connecting adjacent diaphragms by welding or the like to form a bellows shape as a whole. The bellows 32 is configured to urge the stationary ring 36 toward the rotating ring 22 via the adapter 34. With such a configuration, in the mechanical seal 10 of this embodiment, the rotating ring 22 becomes a mating ring that does not move in the axial direction, and the stationary ring 36 becomes a sealing ring that can move in the axial direction.

  Further, the rotating ring 22 and the stationary ring 36 are formed of a material having high wear resistance such as carbon, like the mechanical seal of the prior art.

The mechanical seal 10 of this embodiment further includes a cylindrical shower retainer 40. FIG. 2 is a perspective view showing the configuration of the shower retainer 40.
The shower retainer 40 has an outer diameter smaller than the outer diameter of the sealed space 16 and an inner diameter larger than the outer diameter of the axial flow circulation device 24, and the configuration of the mechanical seal 10 extending from the axial flow circulation device 24 to the bellows 32. It has an axial length that covers the element.

  The shower retainer 40 having such a dimensional shape is concentric with the rotary shaft S around the central axis X of the rotary shaft S so as to cover the bellows 32 from the axial flow circulation device 24 at a radially outward position. It is connected and fixed to the housing.

  The shower retainer 10 is a member made of a metal material, and, as shown in FIG. 2, one end side portion has a cylindrical shape, and the other end side portion has a flange extending outwardly on the outer peripheral surface. It has a protrusion 42 having a rectangular cross section. Further, the projecting portion 42 is formed with a notch 44 that penetrates the projecting portion 42 in the thickness (axis of the shower retainer 10) direction at an angular interval of about 90 degrees. Furthermore, the other end portion of the shower retainer 10 is a thick portion 46 having a small inner diameter.

  Furthermore, the shower retainer 40 includes six through holes 48 formed at an angular interval of about 60 degrees on one end side of the projecting portion 42, and 4 formed at an angular interval of about 90 degrees on the other end side. Two openings 50 are provided. Each of the through hole 48 and the opening 50 penetrates the wall of the shower retainer 40, and partially connects the inside (radially inside) and the outside (diameter outside) of the annular outer peripheral wall of the shower retainer 40. Has a function to communicate.

  In the mechanical seal 10 of the present embodiment, the through hole 48 has a circular shape, and the opening 50 has a shape in which the other end edge of the shower retainer 40 is cut out in a semicircular shape.

  As shown in FIG. 1, the shower retainer 40 has a sealed space (shaft seal) 16 filled with a sealing fluid E and having a substantially cylindrical shape, and a rotary ring 22 and a stationary ring 36 inside. It arrange | positions so that it may divide | segment into 2 radially at the radial direction inner part 16a arrange | positioned, and the radial direction outer part 16b located in the radial direction outer side of the radial direction inner part 16a.

  As shown in FIG. 1, in the shower retainer 40, one end of the protrusion 42 (the left end in FIG. 1) abuts the stuffing box 14, and the other end of the shower retainer 40 (the right end in FIG. 1). Is held between the stuffing box 14 and the mechanical seal cover 12 and attached to the mechanical seal 10.

  As shown in FIG. 1, in the assembled state, the through hole 48 of the shower retainer 40 is at a radially outward position of the stationary ring 36, and the opening 50 is in the radial direction of the connecting portion between the collar 30 and the bellows 32. It is configured to be arranged at the outward position (position on the other end side from the bellows 32). Further, in the assembled state, the distal end of the thick portion 46 having a small inner diameter of the shower retainer 40 is disposed at a radially outward position of the annular adapter 34.

  In the radially inner space, the rotating ring 22 is disposed at one end side position of the stationary ring 36, and the bellows (biasing means) 32 is disposed at the other end side position of the stationary ring 36.

  The axial flow circulation device 26 is a known partial impeller device that is fixed to the rotation shaft S and rotates integrally with the rotation ring S. Since this axial flow type circulation device 26 is disposed radially inward of the shower retainer 40, by rotating integrally with the rotation shaft S, the sealing fluid E in the sealed space 16 is allowed to flow in the sealed space. As shown by an arrow A from one end side (inside the machine, that is, the left side in FIG. 1), it is fed into the radial inner space 16a.

  Further, the casing 14 includes a pump jacket 52 at a radially outward position of the axial flow type circulation device 26. Like the conventional pump jacket, the pump jacket 52 is configured so that the refrigerant is circulated therein, and cools the sealing fluid E in the sealed space 16, in particular, the radially outer space 16 b by heat conduction. .

Next, operation | movement of the mechanical seal 10 of this embodiment is demonstrated.
As described above, when the rotating shaft S rotates, the partial impeller device constituting the axial flow type circulation device 26 also rotates integrally with the rotating shaft S, and the sealing fluid E in the sealed space 16 is allowed to flow in the sealed space. From one end side (inside the machine, that is, the left side in FIG. 1), as shown by an arrow A, the air is fed into the radial inner space 16a.

  As indicated by an arrow B, the sealing fluid E fed into the radial inner space 16a moves in the radial inner space 16a in the direction of the other end side of the sealed space 16 (the outside of the machine, that is, the right side in FIG. 1). And passes near the rotating ring 22 and the stationary ring 36.

  At this time, the seal fluid E removes heat from the rotating ring 22, the stationary ring 36, the seal surface 38 formed between the rotating ring 22 and the stationary ring 36, and the vicinity of the rotating ring 22 and the stationary ring 36. And sludge existing in the vicinity of the seal surface 38 formed between the rotary ring 22 and the stationary ring 36, and the sludge is adjoined between the rotary ring 22 and the stationary ring 36 and between the rotary ring 22 and the stationary ring 36. It is removed from the vicinity of the seal surface 38 formed therebetween.

  As described above, since the distal end of the thick portion 46 of the shower retainer 40 is disposed at the radially outer position of the annular adapter 34, the radially inner space 16 a is more than the radially outer position of the adapter 34. It becomes thin on the other end side. As a result, the seal fluid E that has flowed into the thin portion from the vicinity of the rotating ring 22 and the stationary ring 36 becomes difficult to flow in the bellows direction, and most of the fluid flows into the radial outer space 16 b through the through holes 48.

  As a result, sludge accompanied by the vicinity of the rotating ring 22 and the stationary ring 36 and the vicinity of the seal surface 38 formed between the rotating ring 22 and the stationary ring 36 is difficult to flow into the bellows 32 side.

  The remaining portion of the seal fluid E that flows from the vicinity of the rotating ring 22 and the stationary ring 36 passes through the vicinity of the bellows 32 and accompanies sludge or the like existing in the vicinity of the bellows 32, and as shown by the arrow D, the shower retainer. It flows into the radial outer space 16b through the opening 50 of the 40, and further flows in the one end side direction through the notch 44 formed in the protrusion 42.

  Both the seal fluid E flowing into the radial outer space 16b through the through hole 48 of the shower retainer 40 and the seal fluid E flowing into the radial outer space 16b through the opening 50 of the shower retainer 40 are indicated by arrows E. Then, the radial outer space 16b flows in the direction of one end of the sealed space 16 (inner side, that is, the left side in FIG. 1).

  The seal fluid E whose temperature has been increased by removing heat from the rotary ring 22, the stationary ring 36, and the seal surface 38 formed between the rotary ring 22 and the stationary ring 36 is pumped through the casing 14. It is cooled by the refrigerant in the jacket 52.

  Then, the sealing fluid E cooled and returned to one end of the sealed space is again indicated by an arrow A from the one end side of the sealed space (the inside of the machine, that is, the left side in FIG. 1) by the axial flow circulation device 26. Thus, it is fed into the radial inner space 16a.

  Without being limited to the above-described embodiment of the present invention, various changes and modifications can be made within the scope of the technical idea described in the claims.

  In the mechanical seal 10 of the above embodiment, the bellows is used as the urging means, but other urging means such as a spring can be used.

In the mechanical seal 10 of the above embodiment, the through hole 46 and the opening 50 are provided in the shower retainer 40, but a configuration in which either one is formed may be used.
Moreover, the shape, position, and number of the through-hole 46 and the opening 50 are not limited to the example of the shower retainer of the above-described embodiment, and can be set as appropriate according to the use situation and the like.

  In the mechanical seal 10 of the above embodiment, the thick portion 46 is formed on the other end side of the shower retainer 40. However, when there is no large slurry, the thick portion 46 may be omitted.

  Furthermore, in the said embodiment, although it is the structure which does not perform flushing, this invention is applicable also to the mechanical seal which performs flushing during a driving | operation. In this case, there is an advantage that the flushing flow rate can be reduced.

10: Mechanical seal 12: Mechanical seal cover 14: Stuffing box 16: Sealed space (shaft seal)
16a: radially inward portion 16b: radially outward portion 18: sleeve 20: retainer 22: rotating ring 26: axial flow circulation device (partial impeller)
32: Bellows 36: Stationary ring 38: Sealing surface (sliding surface)
40: Shower retainer 42: Protruding part 44: Notch part 46: Thick part 48: Through hole 50: Opening part S: Rotating shaft E: Sealing fluid

Claims (7)

A mechanical seal that seals the periphery of the rotating shaft by sliding contact between a rotating ring fixed to the rotating shaft and a stationary ring connected to a body-side member through which the rotating shaft passes;
A sealed space which is a cylindrical shaft seal portion in which the rotating ring and the stationary ring are arranged and a sealing fluid is accommodated;
A cylindrical shape that divides the sealed space into a radially inner portion in which the rotating ring and the stationary ring are disposed, and a radially outer portion located radially outward of the radially inner portion. Shower retainer,
A circulation device that feeds the seal fluid into the radially inner portion from one end side of the sealed space and circulates the seal fluid in the sealed space;
The shower retainer has an opening formed on the other end side of the sealed space, and the sealing fluid fed from one end side to the radially inner space by the circulation device on the other end side in the radial direction. Configured to lead to the outer space,
A mechanical seal characterized by that. A pump jacket is formed at an outer position of the outer radial space of the airframe side member.
The mechanical seal according to claim 1. The rotating ring is disposed at one end side position of the stationary ring in the radially inner space;
The mechanical seal further includes:
A biasing means disposed at the other end side position of the stationary ring in the radially inner space, and biasing the stationary ring toward the rotating ring;
The opening includes an opening provided on the other end side from the biasing means.
The mechanical seal according to claim 1 or 2. The biasing means is a metal bellows;
The mechanical seal according to any one of claims 1 to 3. The opening includes a through hole provided at one end side from the biasing means.
The mechanical seal according to any one of claims 1 to 4. The circulation device is an axial flow type circulation device connected to the rotating shaft.
The mechanical seal according to any one of the stationary rings 1 to 3. The mechanical seal is a dead end specification mechanical seal in which the sealing fluid is not injected into the sealed space and the sealing fluid is not discharged from the sealed space.
The mechanical seal according to any one of claims 1 to 6.

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