JP6434830B2 - End contact type mechanical seal - Google Patents

Description

  The present invention relates to an end surface contact type mechanical seal used as a shaft sealing means for rotary equipment such as a pump, a compressor, and a blower.

  As a conventional end face contact type mechanical seal of this type, as disclosed in Patent Document 1, a fixed seal ring fixed to a seal case via an O-ring, and a rotary shaft penetrating the seal case via an O-ring. A movable sealing ring that is held so as to be movable in the axial direction, and a spring that urges the movable sealing ring to press-contact with the fixed sealing ring. It is configured to shield and seal the sealed fluid region that is the outer peripheral side region of the relative rotational sliding contact portion and the non-sealed fluid region that is the inner peripheral side region by the contact action. A knife edge sealing ring (hereinafter referred to as a “conventional mechanical seal”) configured in the shape of a fine tip having a small radial surface width is well known.

  Thus, such a conventional mechanical seal is generally referred to as a knife edge seal, and the fluid in the sealed fluid region (hereinafter referred to as “sealed fluid”) is a component that tends to generate crystals or coagulum, or a slurry component such as solid particles. Even in the case of a high-viscosity fluid that easily generates sludge fluid and deposits, these can be satisfactorily sealed. That is, in a knife edge seal in which one of the two sealing end faces that make relative rotational sliding contact (sealing end face of the knife edge sealing ring) has a small pointed shape with a radial width, the contact surface pressure of both sealing end faces is common. Since it is higher than the end-face contact type mechanical seal, it is possible to prevent the entry and adhesion of slurry components and high-viscosity fluid between sealed end faces as much as possible. Even viscous fluids can be sealed well.

JP 2001-173800 A

  However, in the case of conventional mechanical seals, because the contact surface pressure of both sealing end faces is high, both sealing rings are combined with the fact that both sealing rings are made of a hard material such as silicon carbide having a high friction coefficient. High heat is generated by the relative rotational sliding contact between the end faces, and the relative rotational sliding contact portions of both sealed end faces may be worn. In particular, the sealing end face of the knife edge sealing ring has a pointed shape, and heat and friction are concentrated locally, so that thermal distortion and wear are likely to occur. Therefore, in the long-term use, a large thermal distortion or wear that adversely affects the sealing function by the mechanical seal (hereinafter referred to as “mechanical sealing function”) occurs on the sealing end face of the knife edge sealing ring. There is a possibility that the relative rotational sliding contact is not properly performed and the mechanical seal function cannot be exhibited satisfactorily.

  An object of the present invention is to solve such problems and provide an end face contact type mechanical seal that can exhibit a good mechanical seal function over a long period of time without causing thermal strain on the sealed end face. It is what.

  In the present invention, a fixed sealing ring fixed to one of a seal case and a rotating shaft penetrating through the seal case via an O-ring, and the other is held so as to be movable in the axial direction of the rotating shaft via an O-ring. A movable sealing ring and a spring that urges the movable sealing ring to make a pressing contact with the fixed sealing ring. An end face contact type mechanical seal configured to shield and seal a sealed fluid region, wherein one of the sealing rings is a knife edge sealing ring whose sealing end face is formed into a fine point shape having a radial width. In order to achieve the above object, in particular, the fluid in the sealed fluid region or the fluid in the non-sealed fluid region is a liquid that can always contact the knife edge sealing ring and function as a coolant, and the knife edge sealing ring O-ring contact surface that is in contact with the O-ring, a sealing end surface of the knife-edge sealing ring, and a surface portion of the knife-edge sealing ring that extends from the sealing end surface to the O-ring contact surface and is in contact with the liquid. It is proposed that a series of coating layers made of a material having a higher thermal conductivity coefficient and hardness than the constituent materials of the sealing ring are formed on the liquid surface.

  In a preferred embodiment of such an end surface contact type mechanical seal, the non-sealed fluid region is a closed space partitioned from the outside air region by a secondary seal member disposed between the seal case and the rotating shaft. In addition, a quenching liquid or a sealing liquid that is a liquid that can function as a cooling liquid is supplied to the enclosed space. In this configuration, the liquid contact surface on which the coating layer is formed is the surface portion of the knife edge sealing ring that comes into contact with the liquid. When the fluid in the sealed fluid region is a liquid that can function as a coolant, the liquid contact surface on which the coating layer is formed is a surface portion of a knife edge sealing ring that contacts the liquid. Further, in these configurations, the heat conduction coefficient and the hardness are larger on the sealing end face of the non-knife edge sealing ring which is a sealing ring other than the knife edge sealing ring among the both sealing rings as compared with the constituent material of the sealing ring. It is preferable to form a coating layer made of a material, and further, a surface portion of the non-knife edge sealing ring which is in contact with the O-ring, a sealing end surface of the non-knife edge sealing ring, and the sealing A coating layer made of a material having a larger thermal conductivity coefficient and hardness than the constituent material of the sealing ring on the surface of the knife edge sealing ring extending from the end surface to the O-ring contact surface and in contact with the liquid Are preferably formed in series. In any case, the coating layer is preferably made of diamond.

  In the end face contact type mechanical seal of the present invention, a coating layer (hereinafter referred to as “sealed end face coating layer”) made of a material having a hardness higher than that of the constituent material of the seal ring is provided on the sealing end face of the knife edge sealing ring. Since it is formed, wear and heat generation due to relative rotational sliding contact with the sealing end face of the mating sealing ring (non-knife edge sealing ring) are suppressed as much as possible.

  In addition, since the sealing end face of the knife edge sealing ring has a pointed shape, the heat generated by the relative rotational sliding contact with the sealing end face of the counterpart sealing ring is concentrated and locally becomes high heat. In the contact type mechanical seal, a coating layer (hereinafter referred to as a coating layer formed on the O-ring contact surface) is formed on the O-ring contact surface and the liquid contact surface of the knife edge sealing ring. Since the coating layer formed on the wetted surface is called the “wetted surface coating layer”, the heat generated on the sealed end surface of the knife edge seal ring is a high thermal conductivity coefficient. The heat is effectively radiated and cooled from the coating layer, and local high heat generation at the sealed end face is prevented as much as possible. That is, the sealing end surface coating layer, the liquid contact surface coating layer, and the O-ring contact surface coating layer are a series of materials, and are composed of a material having a large thermal conductivity coefficient as compared with the constituent material of the knife edge sealing ring. The heat generated at the sealing end face of the knife edge sealing ring is transferred from the sealing end face coating layer to the liquid contact surface coating layer, and further from the liquid contact face coating layer to the O-ring contact face coating layer, thereby sealing. The heat of the end face coating layer is dispersed throughout the coating layer including the sealed end face coating layer, and the temperature of the sealed end face coating layer is lowered. Moreover, a part of the liquid contact surface coating layer and the O ring contact surface coating layer (the O ring contact surface coating formed on the O ring contact surface portion from the portion sealed by the O ring on the O ring contact surface to the liquid contact surface) In the layer portion), the heat radiation and cooling from the coating layer are effectively performed by heat exchange with a liquid that is always in contact with these layers and can function as a cooling liquid. Such an effect is particularly prominent when the coating layer is made of diamond.

  Therefore, according to the present invention, even when the fluid to be sealed is the above-described slurry fluid or high-viscosity fluid, the occurrence of wear, heat generation, and thermal distortion at the relative rotational sliding contact portions of both sealing rings is prevented as much as possible. Thus, the mechanical seal function can be satisfactorily exhibited over a long period of time, and an extremely practical end face contact type mechanical seal excellent in durability and reliability as compared with the conventional mechanical seal can be provided.

FIG. 1 is a cross-sectional view showing a first embodiment of an end surface contact type mechanical seal according to the present invention. FIG. 2 is a detailed cross-sectional view showing an enlarged main part of FIG. FIG. 3 is a sectional view showing a second embodiment of the end surface contact type mechanical seal according to the present invention. FIG. 4 is a detailed cross-sectional view showing an enlarged main part of FIG. FIG. 5 is a cross-sectional view showing a third embodiment of an end surface contact type mechanical seal according to the present invention. FIG. 6 is a detailed cross-sectional view showing an enlarged main part of FIG. FIG. 7 is a cross-sectional view showing a fourth embodiment of the end surface contact type mechanical seal according to the present invention. FIG. 8 is an enlarged detailed cross-sectional view showing the main part of FIG. FIG. 9 is a cross-sectional view corresponding to FIG. 2 showing a modification of the first embodiment. FIG. 10 is a cross-sectional view corresponding to FIG. 2 showing another modification of the first embodiment. FIG. 11 is a cross-sectional view corresponding to FIG. 4 showing a modification of the second embodiment. FIG. 12 is a cross-sectional view corresponding to FIG. 4 and showing another modification of the second embodiment. FIG. 13 is a cross-sectional view corresponding to FIG. 6 showing a modification of the third embodiment. FIG. 14 is a cross-sectional view corresponding to FIG. 6 showing another modification of the third embodiment. FIG. 15 is a cross-sectional view corresponding to FIG. 8 showing a modification of the fourth embodiment. FIG. 16 is a cross-sectional view corresponding to FIG. 8 showing another modification of the fourth embodiment.

  FIG. 1 is a cross-sectional view showing a first embodiment of an end surface contact type mechanical seal according to the present invention, and FIG. 2 is a detailed cross-sectional view showing an enlarged main part of FIG. FIG. 3 is a cross-sectional view showing a second embodiment of the end surface contact type mechanical seal according to the present invention, and FIG. 4 is a detailed cross-sectional view showing an enlarged main part of FIG. FIG. 5 is a cross-sectional view showing a third embodiment of the end surface contact type mechanical seal according to the present invention, and FIG. 6 is a detailed cross-sectional view showing an enlarged main part of FIG. FIG. 7 is a cross-sectional view showing a fourth embodiment of the end surface contact type mechanical seal according to the present invention, and FIG. 8 is a detailed cross-sectional view showing an enlarged main part of FIG. In the above description, front and rear refer to the left and right in FIGS.

  An end face contact type mechanical seal (hereinafter referred to as “first mechanical seal”) M1 according to the present invention in the first embodiment is a cylindrical seal case 2 attached to a housing 1 of a rotating device as shown in FIG. A movable seal ring 4 held in the axial direction on the rotary shaft 3 of the rotary device passing through the seal case 2, and a fixed seal ring 5 fixed to the seal case 2 so as to face the movable seal ring 4. And a spring 6 that urges the movable seal ring 4 to press contact with the fixed seal ring 5, and the relative rotational sliding contact action of the seal end faces 4 a and 5 a that are the opposite end faces of the seal rings 4 and 5. The sealed fluid region A, which is the outer peripheral side region of the relative rotational sliding contact portion, and the non-sealed fluid region B, which is the inner peripheral side region thereof, are configured to shield and seal. Radial surface width (see A knife edge seal formed by the knife edge seal ring configured to fine pointed shape of the surface width).

  The seal case 2 is a cylindrical structure having a circular inner periphery, and a rotating shaft 3 protruding from the housing 1 penetrates concentrically.

  As shown in FIGS. 1 and 2, the movable seal ring 4 includes a sealed end face forming portion 4b as a tip portion, a holding portion 4c as an intermediate portion having an inner diameter larger than this, and a base having an inner diameter larger than this. It is an annular body having a constant outer diameter and a substantially L-shaped cross section composed of a spring connecting portion 4d as an end, and is made of a hard material such as silicon carbide. The movable seal ring 4 is a sealed end face 4a which is a smooth annular plane in which the entire front end face (front end face) of the sealed end face shape portion 4b having a rectangular cross section is orthogonal to the axis of the rotary shaft 3 (hereinafter simply referred to as “axis line”). This is a non-knife-edge sealing ring configured as follows, and is fitted to the rotary shaft 3 via the O-ring 7 so as to be movable in the axial direction of the rotary shaft 3 (hereinafter simply referred to as “axial direction”). Is retained. The O-ring 7 is loaded between the opposed peripheral surfaces of the holding portion 4c of the movable seal ring 4 and the rotary shaft 3, and seals between the movable seal ring 4 and the rotary shaft 3 (secondary seal). The base end surface (rear end surface) of the sealed end surface forming portion 4b is pressed and contacted by the fluid pressure in the sealed fluid region A.

  As shown in FIGS. 1 and 2, the fixed seal ring 5 has a constant inner diameter L having a constant inner diameter composed of a sealed end surface forming portion 5b as a distal end portion and a holding portion 5c as a base end portion having a smaller outer diameter. It is a letter-shaped annular body and is made of a hard material such as silicon carbide. The fixed seal ring 5 is located on the non-sealed fluid region B side (front side) of the movable seal ring 4 and is fitted and fixed to the inner peripheral portion of the seal case 2 via the O-ring 8 and the drive pin 9. . That is, the O-ring 8 is formed in an annular space surrounded by the opposing peripheral surface of the holding portion 5 c of the fixed sealing ring 5 and the seal case 2 and the opposing end surface of the sealing end surface forming portion 5 b of the fixed sealing ring 5 and the sealing case 2. It is closely packed and seals (secondary seal) between the fixed seal ring 5 and the seal case 2. The drive pin 9 protrudes from the seal case 2 and engages with a recess 5d formed in the base end portion (front end portion) of the holding portion 5c of the fixed seal ring 5 to seal the fixed seal ring 5 Relative rotation with respect to case 2 is prevented.

  As shown in FIGS. 1 and 2, the fixed sealing ring 5 is formed with a front end side inner peripheral surface of the sealing end surface forming portion 5b as a truncated conical surface that gradually decreases in diameter in the proximal direction (rearward) and a sealed end surface forming portion. The tip end of the sealed end face forming portion 5b is formed into a pointed shape by forming the outer peripheral surface of the tip end side of 5b into a truncated conical surface that gradually increases in diameter in the base end direction, and the tip end face (rear end face) is formed. This is a knife edge sealing ring configured on a sealing end surface 5a which is a small smooth annular plane having a radial surface width perpendicular to the axis. As shown in FIG. 1, the sealing end face 5a of the knife edge sealing ring 5 which is a fixed sealing ring is concentric with the radial center of the sealing end face 4a of the movable sealing ring 4 which is a non-knife edge sealing ring. The width in the radial direction is set to 0.1 to 0.8 mm (more preferably 0.4 to 0.7 mm).

  As shown in FIG. 1, the spring 6 is loaded between the movable seal ring 4 and an annular spring retainer 10 fixed to the rotary shaft 3 on the back side (rear side) thereof, to fix the movable seal ring 4. The seal ring 5 is urged so as to make a pressing contact. The spring retainer 10 is fitted and fixed to the rotary shaft 3 by tightening a fixing screw 11 screwed into the spring retainer 10 to the rotary shaft 3. The spring 6 is a coil spring inserted through the rotary shaft 3, and one end portion 6 a is engaged with a recess 4 e formed in the spring coupling portion 4 d of the movable sealing ring 4 and the other end portion 6 b is formed in the spring retainer 10. The movable seal ring 4 is connected to the spring retainer 10 so as not to be relatively rotatable by being engaged with the recessed portion 10a.

  Further, as shown in FIG. 1, a secondary seal member 12 is disposed between the opposed peripheral surfaces of the seal case 2 and the rotary shaft 3 on the back side (front side) of the fixed seal ring 5. The non-sealed fluid region B is a closed space that is compartmentally sealed from the outside air region C. As the secondary seal member 12, a well-known shaft seal (shaft seal, oil seal, mechanical seal, etc.) is used.

  Further, as shown in FIG. 1, the sealing case 2 has a flushing flow path 13 for ejecting a flushing fluid F toward the outer peripheral surfaces of the sealing rings 4 and 5 toward the relative rotational sliding contact portions of the sealing end surfaces 4a and 5a. And a fixed sealing ring 5 in a non-sealed fluid region B which is a space between the opposed peripheral surfaces of the seal case 2 and the rotary shaft 3 and is sealed off from the outside air region C by the secondary seal member 12. The supply flow path 14 for supplying the quenching fluid Q is formed on the back side of the plate. As the flushing fluid F, the fluid in the sealed fluid region A is used (hereinafter, the fluid in the sealed fluid region A including the flushing fluid is referred to as the sealed fluid F). The quenching fluid Q is selected according to the properties of the sealed fluid F, and generally room temperature water, hot water, steam, nitrogen gas, etc. are used (for example, the sealed fluid F contains a crystal component or a solidified component). In the case of containing slurry liquid, when the crystal or solid matter adhering to the sealed end faces 4a and 5a cannot be washed and removed with normal temperature water, warm water or steam that can wash and remove the crystal as the quenching fluid Q In this example, room temperature water is used. In other words, the first mechanical seal M1 is used under the condition that the fluid in the non-sealed fluid region B (non-sealed fluid), that is, the quenching fluid Q is a liquid that can always contact the knife edge seal ring 5 and function as a coolant. It is what is done.

  Thus, in the first mechanical seal M1, according to the present invention, an O-ring contact surface 5e that is a surface portion of the knife-edge sealing ring (fixed sealing ring) 5 and contacts the O-ring 8, and the knife-edge sealing. It is a sealing end surface 5a of the ring 5 and a surface portion of the knife edge sealing ring 5 extending from the sealing end surface 5a to the O-ring contact surface 5e, and is a quenching fluid (can contact the knife edge sealing ring 5 at all times and function as a cooling liquid. (Liquid) Coating layers 15a, 15b, and 15c made of a material having a large thermal conductivity coefficient and hardness and a small friction coefficient as compared with the constituent material of the sealing ring 5 are formed in series on the liquid contact surface 5f that comes into contact with Q. It is. 2, the O-ring contact surface 5e is a surface portion composed of the outer peripheral surface of the holding portion 5c of the knife edge sealing ring 5 and the base end surface (rear end surface) of the sealing end surface forming portion 5b. Further, as shown in FIG. 2, the wetted surface 5f extending from the sealed end surface 5a to the O-ring contact surface 5e includes a sealed end surface forming portion 4b of the knife edge sealing ring 5, an inner peripheral surface of the holding portion 4c, and a proximal end surface of the holding portion 4c. (Rear end face).

  That is, in the knife edge sealing ring 5 of the first mechanical seal M1, as shown in FIG. 2, the sealing end surface coating layer 15a is formed on the sealing end surface 5a, and the liquid contact surface connected to the sealing end surface coating layer 15a on the liquid contact surface 5f. A coating layer 15b is formed, and an O-ring contact surface coating layer 15c connected to the liquid contact surface coating layer 15b is formed on the O-ring contact surface 15e. In the holding portion 5c of the knife edge sealing ring 5, as shown in FIG. 1, a liquid contact surface coating layer 15b is also formed on the inner peripheral surface of the recess 5d.

  Further, an end face contact type mechanical seal (hereinafter referred to as “second mechanical seal”) M2 according to the present invention in the second embodiment is a knife edge seal configured as shown in FIGS. The fluid Q is a gas (for example, the above-described steam, nitrogen gas, etc.) or a liquid (for example, the above-mentioned hot water) having a higher temperature than the sealed fluid F including the flushing fluid, and the sealed fluid F has a lower temperature than the quenching fluid Q. Liquid (for example, a slurry liquid at room temperature) that is used under the condition that it can function as a cooling liquid.

  Thus, in the second mechanical seal M2, according to the present invention, an O-ring contact surface 5e that is a surface portion of the knife-edge sealing ring (fixed sealing ring) 5 and contacts the O-ring 8, and the knife-edge sealing. The seal end face 5a of the ring 5 and the surface portion of the knife edge seal ring 5 extending from the seal end face 5a to the O-ring contact face 5e, and can function as a liquid to be sealed (always in contact with the knife edge seal ring 5). (Liquid) Coating layers 15a, 15c, and 15d made of a material having a large thermal conductivity coefficient and hardness and a small friction coefficient as compared with the constituent material of the sealing ring 5 are formed in series on the liquid contact surface 5g in contact with F. It is. As shown in FIG. 4, the O-ring contact surface 5e is the same as the O-ring contact surface 5e in the first mechanical seal M1, and the outer peripheral surface of the holding portion 5c of the knife edge sealing ring 5 and the sealing end surface forming portion 5b. It is a surface part which consists of a base end face (rear end face). Further, a liquid contact surface 5g extending from the sealing end surface 5a to the O-ring contact surface 5e is an outer peripheral surface of the sealing end surface forming portion 4b of the knife edge sealing ring 5 as shown in FIG.

  That is, in the knife edge sealing ring 5 of the second mechanical seal M2, as shown in FIG. 4, the sealing end surface coating layer 15a is formed on the sealing end surface 5a, and the liquid contact surface connected to the sealing end surface coating layer 15a is formed on the liquid contact surface 5g. The coating layer 15d is formed, and the O-ring contact surface coating layer 15c connected to the liquid-contact surface coating layer 15d is formed on the O-ring contact surface 5e.

  Since the second mechanical seal M2 has the same structure as the first mechanical seal M1 shown in FIGS. 1 and 2 except for the points described above, the same constituent members in FIGS. The same reference numerals as those used in FIG. 1 and FIG.

  Further, an end face contact mechanical seal (hereinafter referred to as “third mechanical seal”) M3 according to the present invention in the third embodiment is a knife edge seal configured as shown in FIGS. In the mechanical seal M3, unlike the first mechanical seal M1, the movable sealing ring 104 is configured as a knife edge sealing ring, and the fixed sealing ring 105 is configured as a non-knife edge sealing ring.

  That is, as shown in FIGS. 5 and 6, the fixed sealing ring 105 includes a sealed end surface forming portion 105 b having a square cross section as a distal end portion and a holding portion 5 c as a base end portion having a smaller outer diameter. It is an annular body having a substantially L-shaped cross section with a constant inner diameter, and is made of a hard material such as silicon carbide. As shown in FIG. 6, the fixed sealing ring 105 is a non-knife edge sealing ring in which the entire front end surface (rear end surface) of the sealing end surface portion 105b is configured as a sealing end surface 105a which is a smooth annular plane orthogonal to the axis. It is located on the non-sealed fluid region B side (front side) of the movable sealing ring 104 and is fitted and fixed to the inner peripheral portion of the seal case 2 via the O-ring 8 and the drive pin 9. That is, the O-ring 8 is formed in an annular space surrounded by the opposed peripheral surface of the holding portion 5 c of the fixed sealing ring 105 and the seal case 2 and the opposed end surface of the sealed end surface forming portion 105 b of the fixed sealing ring 105 and the seal case 2. It is closely packed and seals (secondary seal) between the fixed sealing ring 105 and the seal case 2. The drive pin 9 protrudes from the seal case 2 and engages with a recess 5d formed in the base end portion (front end portion) of the holding portion 5c of the fixed seal ring 105, thereby sealing the fixed seal ring 105. Relative rotation with respect to case 2 is prevented.

  As shown in FIGS. 5 and 6, the movable sealing ring 104 includes a sealed end surface forming portion 104b that is a tip portion, a holding portion 4c that is an intermediate portion having an inner diameter larger than this, and a base that has an inner diameter larger than that. It is an annular body having a constant outer diameter and a substantially L-shaped cross section composed of a spring connecting portion 4d as an end, and is made of a hard material such as silicon carbide. As shown in FIGS. 5 and 6, the movable sealing ring 104 is formed with a truncated conical surface whose diameter is gradually reduced in the proximal direction (rear) in the distal end side inner peripheral surface of the sealed end surface forming portion 104b and the sealed end surface forming portion. The distal end of the sealing end surface forming portion 104b is formed into a pointed shape by forming the outer peripheral surface of 104b into a frustoconical surface that gradually expands in the proximal direction, and the distal end surface (front end surface) is an axis. This is a knife edge sealing ring formed on a sealing end face 104a which is a minute smooth annular plane having a perpendicular radial surface width. As shown in FIG. 6, the sealing end face 104a of the knife edge sealing ring 104 which is a movable sealing ring is concentric with the central part in the radial direction of the sealing end face 105a of the non-knife edge sealing ring 105 which is a fixed sealing ring. The width in the radial direction is set to 0.1 to 0.8 mm (more preferably 0.4 to 0.7 mm).

  Similar to the first mechanical seal M1, the movable seal ring 104 is fitted and held on the rotary shaft 3 via the O-ring 7 so as to be movable in the axial direction (front-rear direction), as shown in FIG. The O-ring 7 is loaded between the opposed peripheral surfaces of the holding portion 4c of the movable seal ring 4 and the rotary shaft 3, and seals between the movable seal ring 4 and the rotary shaft 3 (secondary seal). The base end face (rear end face) of the sealed end face forming portion 104b is pressed and contacted by the fluid pressure in the sealed fluid region A.

  Thus, like the first mechanical seal M1, the third mechanical seal M3 is a liquid (for example, room temperature water) in which the quenching fluid Q always contacts the knife edge sealing ring 104 and functions as a cooling liquid. O-ring contact surface 104f which is a surface portion of knife edge sealing ring (movable sealing ring) 104 and contacts O-ring 7, and sealing of knife edge sealing ring 104 is used under the conditions. Compared with the constituent material of the sealing ring 104, the end surface 104a and the surface portion of the knife edge sealing ring 104 extending from the sealing end surface 104a to the O-ring contact surface 104f and in contact with the liquid contact surface 104g contacting the quenching fluid Q A series of coating layers 115a, 115b, and 115c made of a material having a high thermal conductivity coefficient and hardness and a small friction coefficient are formed.As shown in FIG. 6, the O-ring contact surface 104f is a surface portion composed of a base end surface (rear end surface) of the sealing end surface forming portion 104b of the knife edge sealing ring 104 and an inner peripheral surface of the holding portion 4c. Further, the liquid contact surface 104g extending from the sealing end surface 104a to the O-ring contact surface 104f is the inner peripheral surface of the sealing end surface forming portion 104b of the knife edge sealing ring 104 as shown in FIG.

  That is, in the knife edge sealing ring 104 of the third mechanical seal M3, as shown in FIG. 6, the sealing end surface coating layer 115a is formed on the sealing end surface 104a, and the liquid contact surface connected to the sealing end surface coating layer 115a is formed on the liquid contact surface 104g. A coating layer 115b is formed, and an O-ring contact surface coating layer 115c connected to the liquid contact surface coating layer 115b is formed on the O-ring contact surface 104f.

  Since the third mechanical seal M3 has the same structure as the first mechanical seal M1 shown in FIGS. 1 and 2 except for the points described above, the same constituent members in FIGS. The same reference numerals as those used in FIG. 1 and FIG.

  Further, the end face contact type mechanical seal (hereinafter referred to as “fourth mechanical seal”) M4 according to the present invention in the fourth embodiment is movable like the third mechanical seal M3 as shown in FIGS. A knife edge seal in which the sealing ring 104 is configured as a knife edge sealing ring and the stationary sealing ring 105 is configured as a non-knife edge sealing ring. Like the second mechanical seal M2, the quenching fluid Q is a gas (for example, the above-mentioned Or liquid having a higher temperature than the sealed fluid F containing flushing fluid (for example, the above-described hot water), and the sealed fluid F is a liquid having a temperature lower than the quenching fluid Q (for example, a slurry at room temperature). Liquid) that is always in contact with the knife-edge sealing ring (movable sealing ring) 104 and can function as a cooling liquid. It is.

  Thus, in the fourth mechanical seal M4, according to the present invention, an O-ring contact surface 104f that is a surface portion of the knife edge sealing ring (movable sealing ring) 104 and contacts the O-ring 7, the knife edge sealing ring. The sealing end surface 104a of 104 and the surface portion of the knife edge sealing ring 104 extending from the sealing end surface 104a to the O-ring contact surface 104f, and the liquid contact surface 104h that contacts the fluid F to be sealed, are used as components of the sealing ring 104. In contrast, coating layers 115a, 115c, and 115d made of a material having a large thermal conductivity coefficient and hardness and a small friction coefficient are formed in series. As shown in FIG. 8, the O-ring contact surface 104f is the same as the O-ring contact surface 104f in the third mechanical seal M1, and the base end surface (rear end surface) of the sealing end surface forming portion 104b of the knife edge sealing ring 104. It is a surface part which consists of the inner peripheral surface of the holding | maintenance part 4c. Further, as shown in FIG. 8, the wetted surface 104h from the sealed end surface 104a to the O-ring contact surface 104f includes an outer peripheral surface of the sealed end surface forming portion 104b of the knife edge sealing ring 104, an outer periphery of the holding portion 4c and the spring connecting portion 4d. This is a surface portion composed of a surface, a base end surface (rear end surface) of the spring connecting portion 4d, an inner peripheral surface of the spring connecting portion 4d, and a base end surface (rear end surface) of the holding portion 4c.

  That is, in the knife edge sealing ring 104 of the fourth mechanical seal M4, as shown in FIG. 8, the sealing end surface coating layer 115a is formed on the sealing end surface 104a, and the liquid contact surface connected to the sealing end surface coating layer 115a is formed on the liquid contact surface 104h. A coating layer 115d is formed, and an O-ring contact surface coating layer 115c connected to the liquid contact surface coating layer 115d is formed on the O-ring contact surface 104f. In the spring connecting portion 4d of the knife edge sealing ring 104, as shown in FIG. 7, a wetted surface coating layer 115d is also formed on the inner peripheral surface of the recess 4e.

  Since the fourth mechanical seal M4 has the same structure as the third mechanical seal M3 shown in FIGS. 5 and 6 except for the points described above, the same structural members in FIGS. The same reference numerals as those used in FIG. 5 and FIG.

  By the way, as the constituent materials of the coating layers 15a, 15b, 15c, 15d and 115a, 115b, 115c, 115d, the constituent materials of the movable seal ring 4, 104 and the fixed seal ring 5, 105 are ceramics, cemented carbide, etc. In any sealing ring component, diamond having a higher thermal conductivity and hardness and a smaller friction coefficient is used. The diamond coating layers 15a, 15b, 15c, 15d and 115a, 115b, 115c, 115d are formed by hot filament chemical vapor deposition, microwave plasma chemical vapor deposition, high frequency plasma, direct current discharge plasma, arc discharge plasma jet. It is carried out by a coating method such as a method or a combustion flame method. In the following description, when it is necessary to distinguish between a sealing ring and a coating layer formed thereon, the former is referred to as a sealing ring base material.

  In each of the mechanical seals M1, M2, M3, M4 configured as described above, the sealing end surfaces 5a, 104a of the knife edge sealing rings 5, 104 are harder than their constituent materials (components of the sealing ring base material). Since the sealing end face coating layers 15a and 115a made of a material having a large friction coefficient and a small friction coefficient are formed, the sealing end face of the fixed sealing ring and the sealing end face of the movable sealing ring directly rotate relative to each other like a conventional mechanical seal. In other words, as compared with the case where the sealing ring base materials are in direct relative sliding contact with each other, the relative rotational sliding between the respective sealing end surfaces 5a, 104a and the mating sealing end surfaces (sealing end surfaces of the non-knife edge sealing rings 4, 105) 4a, 105a. The amount of wear and heat generated at the contact area is reduced. In particular, when the sealing end face coating layers 15a and 115a are made of diamond as described above, diamond is the hardest solid substance present in nature, and any sealing ring constituent material having a friction coefficient of silicon carbide or the like. (Generally, the friction coefficient of diamond is 0.03 (μ), which is 10% higher than that of PTFE (polytetrafluoroethylene) having a much lower friction coefficient than all seal ring components). Therefore, the sealing end surfaces 5a and 104a of the knife edge sealing rings 5 and 104 covered with the sealing end surface coating layers 15a and 115a and the sealing end surfaces of the mating sealing rings (non-knife edge sealing rings) 4 and 105 are used. There is very little wear and heat generated by the relative rotational sliding contact with 4a and 105a.

  Further, since the sealing end surfaces 5a and 104a of the knife edge sealing rings 5 and 104 are pointed, heat generated by relative rotational sliding contact with the sealing end surfaces 4a and 105a of the mating sealing rings 4 and 105 is concentrated. There is a possibility that heat distortion is generated locally and heat distortion that adversely affects the mechanical seal function may occur on the sealed end faces 5a and 104a. Generation of thermal strain on the end faces 5a and 104a is prevented as much as possible.

  That is, the wetted surface coating layers 15b, 15d, 115b, and 115d connected to the sealed end surface coating layers 15a and 115a are formed on the wetted surfaces 5f, 5g, 104g, and 104h of the knife edge seal ring 5, 104 and the knife edge seal ring is formed. O-ring contact surface coating layers 15c, 115c connected to the liquid contact surface coating layers 15b, 15d, 115b, 115d are formed on the O-ring contact surfaces 5e, 104f of 5, 104, and these sealed end surface coating layers 15a, 115a are formed. The liquid contact surface coating layers 15b, 15d, 115b, 115d and the O-ring contact surface coating layers 15c, 115c are a series of materials having a large thermal conductivity coefficient as compared with the constituent material of the knife edge sealing ring 5,104. The knife edge sealing ring 5, 10 is composed of The heat generated on the sealing end surfaces 5a and 104a is transferred from the sealing end surface coating layers 15a and 115a to the liquid contact surface coating layers 15b, 15d, 115b and 115d, and further the liquid contact surface coating layers 15b, 15d, 115b and 115d. To the O-ring contact surface coating layers 15c and 115c. Therefore, the heat of the sealing end surface coating layers 15a and 115a is dispersed throughout the coating layer including the sealing end surface coating layers 15a and 115a, and the temperature of the sealing end surface coating layers 15a and 115a is greatly reduced.

  Moreover, in the first and third mechanical seals M1 and M3, a part of the liquid contact surface coating layers 15b and 115b and the O ring contact surface coating layers 15c and 115c (the O ring 7 on the O ring contact surfaces 5e and 104f). 8, the O-ring contact surface coating layers 15 c and 115 c formed on the O-ring contact surfaces 5 e and 104 f from the contact point to the liquid-contact surfaces 5 f and 104 g, and always function as a cooling liquid. The heat exchange with the quenching fluid Q can effectively release and cool the liquid contact surface coating layers 15b and 115b and the O-ring contact surface coating layers 15c and 115c. Further, in the second and fourth mechanical seals M2 and M4, parts of the liquid contact surface coating layers 15d and 115d and the O ring contact surface coating layers 15c and 115c (the O ring 7 on the O ring contact surfaces 5e and 104f). 8, O-ring contact surface coating layers 15 c and 115 c formed on the O-ring contact surfaces 5 e and 104 f extending from the contact points to the liquid-contact surfaces 5 g and 104 h, respectively, and function as a cooling liquid at all times. Heat exchange with the fluid to be sealed F can effectively release and cool the liquid contact surface coating layers 15d and 115d and the O-ring contact surface coating layers 15c and 115c.

  As a result, when the sealing end faces 5a and 104a of the knife edge sealing rings 5 and 104 have a minute tip shape with a radial width, the contact surface pressure with the sealing end faces 4a and 105a of the mating sealing rings 4 and 105 is high. In addition, the amount of wear and heat generated by the relative rotational sliding contact between both sealed ends are drastically reduced, and the occurrence of thermal strain that adversely affects the knife edge seal function (mechanical seal function) is prevented as much as possible. Is done. In the third and fourth mechanical seals M3 and M4, the relative movement between the O-ring 7 and the movable sealing ring 104, which is a knife-edge sealing ring, is smoothly performed by the low friction coefficient O-ring contact surface coating layer 115c. As a result, the followability of the movable seal ring 104 is improved, and the mechanical seal function is further improved.

  Such a heat dissipation and cooling effect is achieved by forming the coating layers 15a, 15b, 15c, 15d, 115a, 115b, 115c, and 115d with diamond as described above, so that diamond has the highest thermal conductivity among all solid materials. The thermal conductivity is extremely high as compared with sealing ring components such as ceramics and cemented carbides (for example, the thermal conductivity of silicon carbide is 70 to 120 W / mK, whereas the thermal conductivity of diamond is The thermal conductivity is 1000 to 2000 W / mK), which is very remarkable.

  Therefore, the first to fourth mechanical seals M1, M2, M3, and M4 are relatively rotated and slidably contacted with both the sealing rings 4, 5 or 104, 105 even when the sealed fluid F is a slurry fluid or a high viscosity fluid. It is possible to prevent the occurrence of wear, heat generation and thermal distortion in the part as much as possible and to make the mechanical seal function work well over a long period of time. It is more durable and reliable than conventional mechanical seals. An excellent and highly practical knife edge seal.

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

  For example, the first mechanical seal M1 as shown in FIG. 9, the second mechanical seal M2 as shown in FIG. 11, the third mechanical seal M3 as shown in FIG. In the mechanical seal M4, as shown in FIG. 15, the heat conduction coefficient and the sealing end faces 4a and 105a of the non-knife edge sealing rings 4 and 105 are compared with the constituent materials of the sealing ring base material of the sealing rings 4 and 105. It is preferable to form coating layers (sealed end surface coating layers) 15e and 115e made of a material having a high hardness and a small friction coefficient (diamond is optimal). In this way, the heat generated in the sealing end surface coating layers 15a and 115a of the knife edge sealing ring 5 and 104 is applied to the liquid contact surface coating layers 15b, 15d, 115b and 115d and the O-ring contact surface coating layers 15c and 115c. In addition, heat is transferred and dispersed to the sealing end face coating layers 15e and 115e of the mating sealing rings (non-knife edge sealing rings) 4 and 105 having a larger area than the sealing end face coating layers 15a and 115a. Generation of thermal strain due to relative rotational sliding contact between the sealed end faces 5a and 104a of the sealing rings 5 and 104 and the sealed end faces 4a and 105a of the mating sealing rings 4 and 105 can be more effectively prevented. The amount of wear due to contact can also be drastically reduced.

  Further, as shown in FIG. 10 for the first mechanical seal M1 and as shown in FIG. 14 for the third mechanical seal M3, the non-knife edge sealing rings 4 and 105 can function as a coolant. The liquid contact surfaces 4g and 105f that contact the chucking fluid Q and the contact surfaces (O ring contact surfaces) 4f and 105g with the O rings 7 and 8 are connected to the sealed end surface coating layers 15e and 115e formed on the sealed end surfaces 4a and 105a. It is preferable to form the wetted surface coating layers 15f and 115f and the O-ring contact surface coating layers 15g and 115g of the same quality (optimized by diamond). As shown in FIG. 10, the liquid contact surface 4f of the first mechanical seal M1 is the inner peripheral surface of the sealing end surface forming portion 4b of the movable sealing ring 4, and the O-ring contact surface 4f is the base of the sealing end surface forming portion 4b. This is a surface portion composed of an end surface (rear end surface) and an inner peripheral surface of the holding portion 4c of the movable sealing ring 4. Further, as shown in FIG. 14, the liquid contact surface 105f of the third mechanical seal M3 is formed from the sealed end surface forming portion 105b and the inner peripheral surface of the holding portion 5c of the fixed sealing ring 105 and the base end surface (front end surface) of the holding portion 5c. The O-ring contact surface 105g is a surface portion composed of the base end surface (all end surfaces) of the sealing end surface forming portion 105b of the fixed sealing ring 105 and the outer peripheral surface of the holding portion 5c. In addition, the wetted surface coating layer 115f in the third mechanical seal M3 is also formed on the inner peripheral surface of the recess 5d formed in the holding portion 5c of the fixed seal ring 105.

  Further, as shown in FIG. 12 for the second mechanical seal M2 and as shown in FIG. 16 for the fourth mechanical seal M4, the non-knife edge sealing rings 4 and 105 are covered with a liquid that can function as a coolant. The liquid contact surfaces 4h and 105h that contact the sealing fluid F and the contact surfaces (O ring contact surfaces) 4f and 105g with the O rings 7 and 8 are connected to the sealing end surface coating layers 15e and 115e formed on the sealing end surfaces 4a and 105a. It is preferable to form liquid contact surface coating layers 15h and 115h and O-ring contact surface coating layers 15g and 115g of the same quality (optimum for diamond). As shown in FIG. 12, the liquid contact surface 4h of the second mechanical seal M2 includes a sealing end surface forming portion 4b of the movable sealing ring 4, an outer peripheral surface of the holding portion 4c and the spring connecting portion 4d, and a base end surface of the spring connecting portion 4d ( The O-ring contact surface 4f is a base end surface of the sealing end surface forming portion 4b of the movable sealing ring 4 and is a surface portion composed of a rear end surface), an inner peripheral surface of the spring connecting portion 4d, and a base end surface (rear end surface) of the holding portion 4c. It is a surface part which consists of (rear end surface) and the inner peripheral surface of the holding | maintenance part 4c. Further, as shown in FIG. 16, the liquid contact surface 105h of the fourth mechanical seal M4 is the outer peripheral surface of the fixed sealing ring 105, and the O-ring contact surface 105g is the base end surface (front end) of the sealing end surface forming portion 105b of the fixed sealing ring 105. Surface) and the outer peripheral surface of the holding portion 5c.

  By configuring the mechanical seals M1, M2, M3, and M4 as shown in FIG. 10, FIG. 12, FIG. 14, or FIG. 16, the above-described heat dissipation and cooling effects are more effectively exhibited.

  Further, the end surface contact type mechanical seal of the present invention can be suitably used even when a sealing liquid is supplied to the non-sealed fluid region B that is separated from the outside air region C by the secondary seal member 12. it can. That is, under the condition that the sealing liquid is a liquid that can function as a cooling liquid (for example, room temperature water), the sealing liquid is as shown in FIGS. 1 and 2, 5 and 6, 9, 10, 13, or 14. The first or third mechanical seal M1, M3 shown can be suitably used in the same manner as described above.

  In the present invention, a non-sealed fluid region B is provided as an outside air region C without providing an end surface contact type mechanical seal or a secondary seal member 12 provided with a movable seal ring on a seal case and a fixed seal ring on a rotating shaft. The present invention can also be applied to an end surface contact type mechanical seal used under an open condition.

1 Housing 2 Seal Case 3 Rotating Shaft 4 Movable Seal Ring (Non-Knife Edge Seal Ring)
4a Sealing end face of movable sealing ring 4b Sealing end face forming part 4c Holding part 4d Spring connecting part 4e Recessed part 5 Fixed sealing ring (knife edge sealing ring)
5a Sealed end face of fixed seal ring 5b Sealed end face forming part 5c Holding part 5d Recessed part 5e O-ring contact surface 5f Liquid contact surface 5g Liquid contact surface 6 Spring 6a One end part of spring 6b The other end part of spring 7 O ring 8 O ring 9 Drive pin 10 Spring retainer 10a Recess 11 Fixing screw 12 Secondary seal member 13 Flushing flow path 14 Supply flow path 15a Sealed end surface coating layer 15b Liquid contact surface coating layer 15c O-ring contact surface coating layer 15d Liquid contact surface coating layer 15e Sealed end surface Coating layer 15f Wetted surface coating layer 15g Wetted surface coating layer 15h Wetted surface coating layer 104 Movable sealing ring (knife edge sealing ring)
104a Sealed end face of movable seal ring 104f O-ring contact surface 104g Liquid contact surface 104h Liquid contact surface 105 Fixed seal ring (non-knife edge seal ring)
105a Sealed end face of fixed sealing ring 105b Sealed end face forming portion 115a Sealed end face coating layer 115b Liquid contact surface coating layer 115c O-ring contact surface coating layer 115d Liquid contact surface coating layer 115e Sealed end face coating layer 115f Liquid contact surface coating layer 115g Liquid contact Surface coating layer 115h Liquid contact surface coating layer A Sealed fluid region B Unsealed fluid region C Outside air region F Flushing fluid (fluid in the sealed fluid region)
M1 1st mechanical seal (end face contact type mechanical seal)
M2 1st mechanical seal (end face contact type mechanical seal)
M3 1st mechanical seal (end face contact type mechanical seal)
M4 1st mechanical seal (end face contact type mechanical seal)
Q Quenching fluid (fluid in unsealed fluid region)

Claims (4)

A stationary seal ring of silicon carbide which is fixed via an O-ring to Shiruke scan, the seal case the axis of rotation Horanuki through the O-ring movably retained movable seal in the axial direction of the rotary shaft ring And a spring that urges the fixed sealing ring to press contact with the fixed sealing ring, and the sealed fluid region and the non-sealing fluid region by the relative rotational sliding contact action of the sealing end surface that is the opposite end surface of both sealing rings. In the end face contact type mechanical seal in which the fixed sealing ring is a knife edge sealing ring in which the sealing end face is formed in a minute tip shape having a radial width,
The non-sealed fluid region is defined as a closed space separated from the outside air region by a secondary seal member disposed between the seal case and the rotating shaft, and a supply passage formed in the sealed case in the closed space. It is configured to be supplied with a quenching liquid that is a liquid that can function as a cooling liquid,
A surface portion of a knife edge sealing ring, an O-ring contact surface that contacts the O-ring, a sealing end surface of the knife edge sealing ring, and a surface portion of the knife edge sealing ring extending from the sealing end surface to the O-ring contact surface. An end face contact type mechanical seal comprising a series of coating layers made of a material having a higher thermal conductivity and hardness than the constituent material of the sealing ring on the wetted surface in contact with the quenching liquid . On the sealing end face of the non-knife edge sealing ring which is a sealing ring other than the knife edge sealing ring among the both sealing rings, a coating layer made of a material having a higher thermal conductivity coefficient and hardness than the constituent materials of the both sealing rings. The end face contact type mechanical seal according to claim 1, wherein the end face contact type mechanical seal is formed. A surface portion of a non-knife edge sealing ring that is a sealing ring other than the knife edge sealing ring among the two sealing rings, and is an O-ring contact surface that contacts the O-ring, a sealing end surface of the non-knife edge sealing ring, and the sealing end surface The surface portion of the non-knife edge sealing ring extending from the O-ring contact surface to the liquid contact surface in contact with the quenching liquid is made of a material having a higher thermal conductivity coefficient and hardness than the constituent material of the sealing ring. The end face contact type mechanical seal according to claim 1 or 2 , wherein a series of coating layers are formed . The coating layer is characterized that you have been configured in a diamond, the end surface contact type mechanical seal according to any one of claims 1 to 3.

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