JP2018146079A - Mechanical seal for slurry fluid - Google Patents

Abstract

To provide a mechanical seal for a slurry fluid capable of preventing the lowering of the aligning function of a retainer holding a stationary sealing ring for sealing slurry fluid. A mechanical seal 3 for a slurry fluid includes a rotary seal ring 21 attached to a rotary shaft 61 so as to be integrally rotatable, and an annular retainer 22 attached to a seal case 52 surrounding the rotary shaft 61. A stationary sealing ring 23 that is held by the retainer 22 and seals the slurry fluid by sliding contact with the rotating sealing ring 21; an elastic bellows 24 that presses the stationary sealing ring 23 toward the rotating sealing ring 21 via the retainer 22; A ring member 32 is provided that is attached to the seal case 52 with a minute gap between the retainer 22 and the outer peripheral surface 22b not facing the in-machine region C where the fluid is sealed. [Selection] Figure 1

Description

  The present invention relates to a mechanical seal for slurry fluid.

  Conventionally, as shown in FIG. 4, as a seal for a slurry fluid, which is a sealed fluid inside a rotating device, as shown in FIG. 4, a rotary seal ring 102 provided integrally with the rotary shaft 101 and a casing 103 side. An annular retainer 104 made of metal, a stationary seal ring 105 held by the retainer in an axial direction facing the rotary seal ring 102, and the stationary seal ring 105 on the side of the rotary seal ring 102 via the retainer 104 There is known a mechanical seal 110 including an elastic bellows 106 that presses against (see, for example, Patent Document 1).

  In the rotating device provided with such a mechanical seal 110, an in-machine region 107 for sealing slurry fluid is formed on the inner peripheral side of the stationary sealing ring 105, the retainer 104 and the elastic bellows 106. Is arranged with a cylindrical baffle 108 that aligns the retainer 104 with respect to the casing 103 (an anti-swaying that keeps the retainer 104 from swinging within a certain range). That is, the retainer 104 is aligned by bringing the inner peripheral surface of the retainer 104 closer to the outer peripheral surface of the baffle 108. The baffle 108 is fixed to a seal case 109 on the casing 103 side.

JP 2006-125597 A

  In the mechanical seal 110, when hard sludge is contained in the slurry fluid in the in-machine region 107, the sludge bites into a gap formed between the inner peripheral surface of the retainer 104 and the outer peripheral surface of the baffle 108. There is. When sludge is bitten in this way, the retainer 104 and the baffle 108 are worn, and the aligning function of the retainer 104 by the baffle 108 gradually decreases. When the aligning function of the retainer 104 is lowered, the back side member of the mechanical seal 110 is shaken or vibrated, resulting in damage to the back side member (for example, the elastic bellows 106), and the slurry fluid leaks to the outside. There was a problem that there was a risk of doing.

  Therefore, it is conceivable to align the retainer 104 by increasing the outer diameter of the retainer 104 and bringing its outer peripheral surface closer to the inner peripheral surface of the seal case 109. However, in this case, the seal case 109 is easily damaged when the retainer 104 contacts the seal case 109. When the seal case 109 is damaged in this way, the aligning function of the retainer 104 is lowered, and the back side member (for example, the elastic bellows 106) of the mechanical seal 110 is damaged, and a large amount of slurry fluid may leak to the outside. As a result, the above problem cannot be solved.

  The present invention has been made in view of such circumstances, and provides a mechanical seal for a slurry fluid that can prevent the aligning function of a retainer holding a stationary sealing ring that seals the slurry fluid from being deteriorated. With the goal.

  The slurry fluid mechanical seal of the present invention is held by the rotary seal ring attached to the rotary shaft side so as to be integrally rotatable, an annular retainer attached to the casing side surrounding the rotary shaft, and the retainer. A stationary sealing ring that seals slurry fluid by sliding contact with the rotating sealing ring; an elastic bellows that presses the stationary sealing ring toward the rotating sealing ring via the retainer; and an outer peripheral surface and an inner periphery of the retainer A ring member attached to the casing in a state where a minute gap is formed between the surface and a peripheral surface not facing the in-machine region where the slurry fluid is sealed.

  According to the present invention, the ring member is formed with a minute gap between the outer peripheral surface and the inner peripheral surface of the retainer that holds the stationary sealing ring and the peripheral surface that does not face the in-machine region where the slurry fluid is sealed. Since the retainer is arranged with respect to the casing side by the ring member, hard sludge contained in the slurry fluid is not caught between the retainer and the ring member. Thereby, it can prevent that the aligning function of a retainer falls due to the biting of sludge. Further, since the retainer is aligned with the ring member attached to the casing side, the retainer does not contact the casing side. For this reason, it is possible to prevent the aligning function of the retainer from being deteriorated due to damage on the casing side.

In the slurry fluid mechanical seal, it is preferable that the ring member is made of a material having a smaller elastic modulus than the retainer and is detachably attached to the casing side.
In this case, since the ring member is made of a material softer than the retainer, the retainer can be prevented from coming into contact with the ring member and being worn. Further, since the ring member is detachably attached to the casing side, even if the ring member is worn by contact with the retainer, it can be easily replaced with a new ring member.

  The mechanical seal for slurry fluid is a mechanical seal inside the machine in a double type mechanical seal formed by forming a sealing liquid region where a sealing liquid is introduced between a pair of mechanical seals arranged inside and outside the machine. The ring member is attached to the casing with a minute gap between the retainer and an outer peripheral surface facing the liquid sealing region, and the seal is attached to at least one place in the circumferential direction of the ring member. It is preferable that the sealing passage through which the liquid passes is formed so as to penetrate in the axial direction.

  In this case, in the mechanical seal inside the double-type mechanical seal, the ring member that aligns the retainer with respect to the casing is disposed in the sealing liquid region where the sealing liquid is introduced, but at least in the circumferential direction of the ring member. Since the sealing liquid passage through which the sealing liquid passes is formed at one place, the circulation of the sealing liquid is not hindered by the ring member. Therefore, it is possible to prevent the aligning function of the retainer from deteriorating without inhibiting the application of back pressure to the retainer and the elastic bellows.

  ADVANTAGE OF THE INVENTION According to this invention, it can prevent that the aligning function of the retainer holding the stationary sealing ring which seals slurry fluid falls.

It is a sectional view of a double type mechanical seal device provided with a mechanical seal for slurry fluid concerning one embodiment of the present invention. It is an expanded sectional view of the 2nd mechanical seal inside a machine. It is a front view of a ring member. It is sectional drawing of the conventional mechanical seal.

Next, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
[overall structure]
FIG. 1 is a cross-sectional view of a double-type mechanical seal device including a slurry fluid mechanical seal according to an embodiment of the present invention. This double type mechanical seal device 1 is provided between a seal case 52 attached to a casing 51 and a rotary shaft 61 of the rotary device in a rotary device such as a pump that handles slurry fluid (sealed fluid). Yes. The seal case 52 is arranged in a partition area that partitions the outside area A and the inside area C.

  The double-type mechanical seal device 1 includes a first mechanical seal 2 on the outside of the machine and a second on the inside of the machine that are arranged in parallel with each other at a predetermined interval in the axial direction of the rotation shaft 61 (hereinafter simply referred to as “axial direction”). A mechanical seal 3 is provided. Between the first mechanical seal 2 and the second mechanical seal 3, an annular sealing region B into which a sealing solution for sealing and cooling is introduced is formed. The first mechanical seal 2 seals between the outside area A and the sealed area B, and the second mechanical seal 3 seals between the sealed area B and the inside area C. .

  The seal case 52 has a case ring portion 53 formed in an annular shape and a cylindrical case cylinder portion 54 extending from the case ring portion 53 to the inside of the machine. The case ring portion 53 is fixed to the casing 51 with bolts 56 while being sandwiched between the outer surface of the casing 51 and the flange 55. The outer peripheral surface of the case cylindrical portion 54 is fitted to the inner peripheral surface of the casing 51.

  The case ring portion 53 is provided with a supply path 53a for supplying the sealing liquid to the sealing liquid area B and a discharge path 53b for discharging the sealing liquid in the sealing liquid area B to the outside. The first and second mechanical seals 2 and 3 can be cooled by the sealing liquid supplied into the sealing liquid region B from the supply path 53a. Moreover, the sealing liquid which cooled the 1st and 2nd mechanical seals 2 and 3 is discharged | emitted outside from the discharge path 53b. The pressure of the sealing liquid in the sealing liquid area B is set higher than the pressure of the slurry fluid in the in-machine area C, and the slurry fluid in the in-machine area C is prevented from leaking into the sealing liquid area B.

[First mechanical seal]
The first mechanical seal 2 on the outside of the machine includes a rotary seal ring 5 attached to the rotary shaft 61 side so as to be integrally rotatable, and a stationary seal ring 6 attached to the casing 51 side. The rotary seal ring 5 is made of, for example, a SiC sintered body, and a seal surface 5a is formed at an end portion outside the machine. The rotary seal ring 5 is fitted and fixed to the drive ring 8 with its outer peripheral side sealed by an O-ring 7. The drive ring 8 is provided with a plurality of pins 8a (only one is shown in FIG. 1) protruding at a predetermined interval in the circumferential direction. Each pin 8 a is engaged with an engagement hole 5 b formed in the rotary seal ring 5. Thereby, the rotation seal ring 5 is restricted from rotating relative to the drive ring 8.

  The drive ring 8 is formed with a plurality of screw holes 8b (only one is shown in FIG. 1) with a predetermined interval in the circumferential direction, and a set screw 9 is provided in each screw hole 8b. It is screwed. By tightening the set screw 9, the tip portion presses the outer peripheral surface of the sleeve 10. The sleeve 10 is fitted to the outer peripheral surface of the rotary shaft 61 so as to be integrally rotatable by tightening a set screw 17 screwed into a stopper ring 16 disposed at an end portion outside the machine. Thereby, the drive ring 8 is fixed to the rotating shaft 61 side. A space between the inner peripheral surface of the drive ring 8 and the outer peripheral surface of the sleeve 10 is sealed with an O-ring 11. Further, the axially opposite ends of the inner peripheral surface of the sleeve 10 and the outer peripheral surface of the rotary shaft 61 are sealed by O-rings 18 and 19.

  The stationary seal ring 6 is made of, for example, a SiC sintered body, and a seal surface 6a with which the seal surface 5a of the rotary seal ring 5 is slidably contacted is formed at the inner end of the machine. The stationary seal ring 6 is fixed to the holding ring 12 by shrink fitting. A plurality of insertion holes 12a (only one is shown in FIG. 1) are formed in the holding ring 12 at predetermined intervals in the circumferential direction. The drive pins 13 are inserted into the insertion holes 12a. And fixed to the side surface of the flange 55. Thereby, the relative rotation with respect to the flange 55 is regulated while the holding ring 12 is held so as to be movable in the axial direction with respect to the flange 55 together with the stationary sealing ring 6.

  A plurality of springs 14 (only one is shown in FIG. 1) are provided between the holding ring 12 and the flange 55 at predetermined intervals in the circumferential direction to press the holding ring 12 toward the inside of the machine. As a result, the stationary seal ring 6 is pressed toward the rotary seal ring 5 by the spring 14. A space between the outer peripheral surface of the holding ring 12 and the inner peripheral surface of the flange 55 is sealed with an O-ring 15.

[Second mechanical seal]
The second mechanical seal (slurry fluid mechanical seal) 3 inside the machine includes a rotary seal ring 21 attached to the rotary shaft 61 so as to be integrally rotatable, an annular retainer 22 attached to the casing 51, and a retainer 22. A stationary seal ring 23 held on the retainer 22, an elastic bellows 24 having one end attached to the retainer 22, and an annular adapter 25 to which the other end of the elastic bellows 24 is attached.

  The rotary seal ring 21 is made of, for example, a SiC sintered body, and a seal surface 21a is formed at an end portion inside the machine. The outer periphery of the rotary seal ring 21 is fixed to the metal holding ring 26 by shrink fitting. The holding ring 26 is formed with an annular groove 26a having an outer peripheral side opened, and an annular collar 27 is inserted into the annular groove 26a. Although not shown, the collar 27 is formed with a plurality of screw holes penetrating in the axial direction at predetermined intervals in the circumferential direction, and the collar portion 10a of the sleeve 10 and the holding ring 26 are formed in these screw holes. The tip of a bolt 28 that passes through the shaft in the axial direction is screwed. Thereby, the holding ring 26 is restricted from rotating relative to the sleeve 10. The holding ring 26 and the flange portion 10a are sealed with a gasket 34.

  FIG. 2 is an enlarged cross-sectional view of the second mechanical seal 3. The stationary sealing ring 23 of the second mechanical seal 3 is made of, for example, a SiC sintered body, and the sealing surface 21a of the rotary sealing ring 21 is slidably contacted with an end portion on the outside of the machine to seal the slurry fluid in the in-machine region C. A sealing surface 23a is formed. The outer periphery of the stationary seal ring 23 is fixed to the metal retainer 22 by shrink fitting.

  The elastic bellows 24 is formed in a bellows cylinder shape, one end is fixed to the end surface of the retainer 22 on the machine inner side (the side opposite to the seal surface 23a in the axial direction) by welding, and the other end is the machine outer side of the adapter 25 ( It is fixed to the end surface on the seal surface 23a side in the axial direction by welding. That is, the retainer 22, the elastic bellows 24, and the adapter 25 are integrated, and are constituent elements of a broad sense. An annular bent portion 54a extending inward in the radial direction is formed at the end of the case cylindrical portion 54 on the machine inner side, and the end surface of the adapter 25 on the machine inner side is formed on the side surface of the bent portion 54a on the machine outer side. The bolt 29 (see FIG. 1) is fixed to the bent portion 54a in the contact state.

  Thereby, the elastic bellows 24 presses the stationary sealing ring 23 toward the rotary sealing ring 21 via the retainer 22. Further, as described above, the pressure of the sealing liquid in the sealing liquid region B is set higher than the pressure of the slurry fluid in the in-machine region C, so that the back pressure acts on the retainer 22 and the elastic bellows 24. . Therefore, in addition to the pressing force of the elastic bellows 24, the back pressure by the sealing liquid acts on the stationary seal ring 23, so that the sealing performance of the second mechanical seal 3 can be enhanced.

[Alignment mechanism]
The second mechanical seal 3 further includes a ring member 32 that aligns the retainer 22 with respect to the seal case 52 on the casing 51 side. Here, the alignment refers to a steady rest that suppresses the swing of the retainer within a certain range. The ring member 32 is made of a material having a smaller elastic modulus than the metal retainer 22, that is, a material softer than the metal retainer 22. The ring member 32 of the present embodiment is made of PTFE (polytetrafluoroethylene), for example.

  The ring member 32 is disposed with a minute gap between the retainer 22 and the peripheral surface not facing the in-machine region C. The ring member 32 according to the present embodiment is arranged with a minute gap between the inner peripheral surface 32a and the outer peripheral surface 22b facing the sealing region B. The outer peripheral surface of the ring member 32 is detachably fitted to an annular recess 54 b formed on the inner periphery of the case cylindrical portion 54. Thereby, the ring member 32 aligns the outer peripheral side of the retainer 22 with respect to the seal case 52 (case cylindrical portion 54).

  FIG. 3 is a front view of the ring member 32. The ring member 32 of the present embodiment is formed in an end ring shape, and the sealing liquid passes between the end faces 32b, 32c on both sides in the circumferential direction in the axial direction (perpendicular to the paper surface in FIG. 3). A passage 33 is formed. That is, a sealing liquid passage 33 through which sealing liquid passes is formed in one place in the circumferential direction of the ring member 32 so as to penetrate in the axial direction.

  The size of the sealing liquid passage 33 is not particularly limited in the present invention. Preferably, the angle α formed by the end faces 32b and 32c centering on the center point X of the ring member 32 is 10 ° or more and It is 20 degrees or less. The angle α is preferably 10 ° or more from the viewpoint of not inhibiting the flow of the sealing liquid. In addition, the angle α is desirably 20 ° or less from the viewpoint that the ring member 32 can effectively exert the function of the retainer 22.

[Function and effect]
As described above, according to the mechanical seal for the slurry fluid (second mechanical seal 3) of the present embodiment, a minute gap is formed between the retainer 22 that holds the stationary seal ring 23 and the outer peripheral surface 22b that does not face the in-machine region C. Since the ring member 32 is opened and the retainer 22 is aligned with the seal case 52 by the ring member 32, hard sludge contained in the slurry fluid is caught between the retainer 22 and the ring member 32. There is nothing. Thereby, it can prevent that the aligning function of the retainer 22 falls due to the biting of sludge. Further, since the retainer 22 is aligned with the ring member 32 attached to the seal case 52, the retainer 22 does not contact the seal case 52. For this reason, it is possible to prevent the aligning function of the retainer 22 from being deteriorated due to breakage of the seal case 52. As described above, as the aligning function of the retainer 22 is lowered, the retainer 22, the elastic bellows 24, and the adapter 25 (broad bellows), which are the back side members of the second mechanical seal 3, generate vibrations and vibrations. Thus, it is possible to effectively prevent the back side member (for example, the elastic bellows 24) from being damaged and the slurry fluid in the in-machine region C from leaking outside.

  Further, since the ring member 32 is made of a material having a smaller elastic modulus than the retainer 22, that is, a material softer than the retainer 22, it is possible to suppress the retainer 22 from coming into contact with the ring member 32 and being worn. Further, since the ring member 32 is detachably attached to the seal case 52, even if the ring member 32 is worn due to contact with the retainer 22, it can be easily replaced with a new ring member 32.

  The ring member 32 is disposed in the sealing liquid region B where the sealing liquid is introduced. The ring member 32 has a sealing liquid passage 33 through which the sealing liquid passes. The distribution of the sealing liquid is not hindered. Therefore, it is possible to prevent the aligning function of the retainer 22 from deteriorating without inhibiting the application of back pressure to the retainer 22 and the elastic bellows 24.

[Others]
The ring member 32 in the above embodiment is arranged with a small gap between the retainer 22 and the outer peripheral surface that does not face the in-machine region C. However, when the outer peripheral side of the retainer 22 is the in-machine region C, Further, a minute gap may be provided between the retainer 22 and the inner peripheral surface.
Further, the sealing passage 33 in the above embodiment is formed between the end faces 32b, 32c on both sides in the circumferential direction of the end-ring ring member 32, but the ring member 32 is formed in an endless ring shape and its thickness. A through hole or a through groove penetrating in the direction (axial direction) may be used as the sealed liquid passage. In this case, a plurality of through-holes or through-grooves that are sealed liquid passages may be formed in the circumferential direction.

  Further, in the above embodiment, the baffle is not provided on the inner peripheral side of the retainer 22, but the baffle is disposed with a minute gap between the retainer 22 and the outer periphery of the retainer 22. In addition to the surface, alignment may be performed on the inner peripheral side. In this case, even when sludge is caught between the retainer 22 and the baffle and the aligning function on the inner peripheral side of the retainer 22 is reduced or lost, the aligning function on the outer peripheral side of the retainer 22 is maintained. Therefore, it is possible to prevent the aligning function of the retainer 22 from being reduced due to sludge biting.

  Moreover, although the mechanical seal for slurry fluid of the present invention has been described as a mechanical seal inside the double type mechanical seal device, the retainer holding the stationary seal ring is pressed against the rotary seal ring side by an elastic bellows. If there is, it can be applied to a single-type mechanical seal.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Double type mechanical seal apparatus 2 1st mechanical seal 3 2nd mechanical seal (mechanical seal for slurry fluid)
DESCRIPTION OF SYMBOLS 21 Rotating sealing ring 22 Retainer 22b Outer peripheral surface 23 Stationary sealing ring 24 Elastic bellows 32 Ring member 33 Sealing passage 51 Casing 61 Rotating shaft B Sealing area C In-machine area

Claims (3)

A rotary seal ring attached to the rotary shaft side so as to be integrally rotatable;
An annular retainer attached to the casing surrounding the rotating shaft;
A stationary sealing ring that is held by the retainer and seals slurry fluid by sliding contact with the rotary sealing ring;
An elastic bellows that presses the stationary seal ring toward the rotary seal ring through the retainer;
A ring member attached to the casing side with a minute gap between an outer peripheral surface and an inner peripheral surface of the retainer and a peripheral surface not facing an in-machine region where the slurry fluid is sealed; A mechanical seal for slurry fluid.   The mechanical seal for a slurry fluid according to claim 1, wherein the ring member is made of a material having a smaller elastic modulus than the retainer and is detachably attached to the casing side. The mechanical seal for slurry fluid is a mechanical seal inside the machine in a double type mechanical seal formed by forming a sealing liquid region where a sealing liquid is introduced between a pair of mechanical seals arranged inside and outside the machine. ,
The ring member is attached to the casing side with a minute gap between the retainer and the outer peripheral surface facing the liquid sealing region,
The mechanical seal for slurry fluid according to claim 1 or 2, wherein a sealing liquid passage through which the sealing liquid passes is formed in at least one place in a circumferential direction of the ring member so as to penetrate in an axial direction.

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