JP2008240837A - Mechanical seal device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mechanical seal device having suction/discharge function for discharging air in a pump casing and sucking air into the pump casing in addition to sealing function. <P>SOLUTION: A fixing ring 42 is provided in a shaft hole 17 of the pump casing 12 penetrated with a rotation shaft 14, a rotation ring 43 is externally fitted to a rotation shaft 14, and a floating ring 44 is arranged between the fixing ring 42 and the rotation shaft 14. A suction/discharge passage 60 communicated with the inside and the outside of the pump casing 12 while passing between a lower surface of the rotation ring 43 and an upper surface of the floating ring 44 is provided, and the floating ring 44 can be vertically moved to an open position O and a close position for opening/closing the suction/discharge passage 60. At he close position, the upper surface of the floating ring 44 is abutted on a lower surface of the rotation ring 43, a clearance between the floating ring 44 and the rotation ring 43 is sealed, and the floating ring 44 is ascended in the close direction by buoyancy of water in the pump casing 12. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a mechanical seal device with an intake / exhaust function provided in a pump.

  Conventionally, for example, as shown in FIG. 11, an impeller 13 and a vertical rotating shaft 14 that rotates the impeller 13 are provided in the pump casing 12 of the vertical shaft mixed flow pump 11. A downward suction port 15 is formed at the lower end portion of the pump casing 12, and a lateral discharge port 16 is formed at the upper end portion.

  The upper part of the rotating shaft 14 passes through a shaft hole 17 formed in the upper part of the pump casing 12 and projects upward from the pump casing 12. An electric motor 18 that rotates the rotary shaft 14 is provided above the pump casing 12. A mechanical seal device 19 is provided in the shaft hole 17, and the pump casing 12 and the rotary shaft 14 are sealed by the mechanical seal device 19. An intake / exhaust device 20 that exhausts air in the pump casing 12 or sucks air into the pump casing 12 is provided at the upper end of the pump casing 12. The intake / exhaust device 20 includes an intake / exhaust pipe 21 and an intake / exhaust valve 22.

  According to this, when the water level in the tank 23 rises to a predetermined drainage start water level and the pump 11 is started, the water in the tank 23 is sucked from the suction port 15 by the rotation of the impeller 13, and the pump casing 12. The water level inside rises gradually. At this time, by opening the intake / exhaust valve 22, the air in the pump casing 12 is pushed by the rising water surface and exhausted to the outside through the intake / exhaust pipe 21. As a result, air is prevented from being sent into the discharge-side pipe 24, thereby preventing air accumulation in the discharge-side pipe 24 and the occurrence of an air hammer. When the air in the pump casing 12 is exhausted, the intake / exhaust valve 22 is closed. During operation of the pump 11, water sucked from the suction port 15 passes through the pump casing 12 and is discharged from the discharge port 16.

  Further, when the water level in the tank 23 is lowered and the pump 11 is stopped, the rotation of the impeller 13 is stopped, so that the water in the pump casing 12 tends to descend (fall down) and the pressure in the pump casing 12 is reduced. At this time, by opening the intake / exhaust valve 22, external air is sucked into the pump casing 12 through the intake / exhaust pipe 21, and the pump casing 12 is maintained at atmospheric pressure. The water surface in 12 falls (falls down), and the water in the pump casing 12 is smoothly discharged into the tank 23 from the suction port 15.

The following Patent Document 1 describes a sealing device provided in a vertical pump. A float chamber is provided above the impeller in the pump body, the float is accommodated in the float chamber, and a seal is provided on the upper surface of the float. The seal ring is provided on the rotating shaft that rotates the impeller, and when the impeller stops and water enters the float chamber, the float rises and the seal member presses against the seal ring. Are listed.
JP-A-60-182390

  However, since the intake / exhaust device 20 is provided at another location away from the mechanical seal device 19 in the structure shown in FIG. 11, there is a problem and structure that it is necessary to secure a space for providing the intake / exhaust device 20. There is a problem of increasing complexity.

  Further, when the vertical shaft mixed flow pump 11 is operated with the intake / exhaust valve 22 closed to drain the water in the tank 23, an air pocket is generated immediately below the mechanical seal device 19, and the mechanical seal device 19 is There has been a problem that there is a possibility of causing a seal failure by sliding in a dry state.

  Further, when the impeller 13 is stopped with the intake / exhaust valve 22 closed, the water in the pump casing 12 tends to descend and the inside of the pump casing 12 falls to a low pressure (negative pressure) less than the atmospheric pressure, and the mechanical seal There is a possibility that the behavior of the device 19 becomes unstable.

  Further, the sealing device described in Patent Document 1 does not have an intake / exhaust function for exhausting air in the pump casing or sucking air into the pump casing, and can perform intake and exhaust quickly and reliably. There is no problem.

  It is an object of the present invention to provide a mechanical seal device having an intake / exhaust function that exhausts air in a pump casing or sucks air into a pump casing quickly and reliably in addition to a sealing function.

In order to achieve the above object, the first invention is provided in a pump that rotates and feeds an impeller,
A mechanical seal device for sealing a shaft between a rotary shaft for rotating an impeller and a pump casing,
A fixed ring is provided in the shaft hole of the pump casing through which the rotating shaft passes,
A rotating ring is fitted around the rotating shaft,
A floating ring is arranged between the stationary ring and the rotating shaft,
An intake / exhaust passage is provided between the lower surface of the rotary ring and the upper surface of the floating ring and communicates with the inside and the outside of the pump casing,
The floating ring is movable in a vertical direction over a closed position where it rises to close the intake / exhaust passage and an open position where it descends to open the intake / exhaust passage,
The space between the inner peripheral surface of the stationary ring and the outer peripheral surface of the floating ring is sealed with a seal member,
In the closed position, the upper surface of the floating ring contacts the lower surface of the rotating ring, and the space between the floating ring and the rotating ring is sealed,
The floating ring is configured to move in the closing direction by the buoyancy of the liquid in the pump casing.

  According to this, when the pump is stopped, the floating ring is lowered to the open position by its own weight, and the intake / exhaust passage is opened. Thereafter, when the pump is started, the liquid is sucked from the suction port by the rotation of the impeller, and the liquid level in the pump casing gradually rises. At this time, the air in the pump casing is pushed by the rising liquid level and exhausted to the outside through the intake / exhaust passage.

  As the liquid level further rises, the floating ring rises to the closed position due to the buoyancy of the liquid in the pump casing, the intake and exhaust passages are closed, and the upper surface of the floating ring comes into contact with the lower surface of the rotating ring that rotates with the rotating shaft. The lower surface of the rotating ring slides against the upper surface of the floating ring. As a result, during pump operation, the upper surface of the floating ring is pressed against the lower surface of the rotating ring by the pressure and buoyancy in the pump casing, the space between the floating ring and the rotating ring is sealed, and the liquid sucked from the suction port The liquid is discharged from the discharge port through the pump casing without leaking from the mechanical seal device.

  Further, when the pump is stopped, the impeller stops rotating and the liquid feeding is stopped, so that the liquid level in the pump casing gradually falls (falls down), the pressure in the pump casing is reduced, and the floating ring is lowered. Since the buoyancy of the liquid acting on the fluid is reduced, the floating ring is lowered to the open position, and the intake / exhaust passage is opened. As a result, external air is sucked into the pump casing through the intake / exhaust passage, and the pressure in the pump casing is maintained at atmospheric pressure without decreasing to a low pressure (negative pressure) below atmospheric pressure. Thus, the liquid level in the pump casing is lowered, and the liquid in the pump casing is smoothly discharged from the suction port to the outside.

Thus, since the mechanical seal device has an intake / exhaust function in addition to the seal function, it is not necessary to separately provide an intake / exhaust device as in the prior art.
In addition, when an air pocket is generated directly under the mechanical seal device during the pump operation, the buoyancy of the liquid acting on the floating ring is reduced by the air pool, so the floating ring is lowered to the open position by its own weight, and the intake / exhaust passage Is opened, and air in the air reservoir is exhausted to the outside of the pump casing through the intake / exhaust passage. As a result, the liquid level in the pump casing rises and the buoyancy of the liquid acting on the floating ring increases, so that the floating ring rises to the closed position by the buoyancy, the intake and exhaust passages are closed, and the upper surface of the floating ring Comes into contact with the lower surface of the rotating ring that rotates together with the rotating shaft, and the lower surface of the rotating ring slides on the upper surface of the floating ring to seal between the floating ring and the rotating ring. Thereby, there is no air pocket and it is possible to prevent the mechanical seal device from sliding due to being dry and causing a seal failure.

  In addition, when the pump is stopped, the floating ring automatically descends to the open position in conjunction with the drop in the liquid level, so the pump casing does not become a low pressure (negative pressure) below atmospheric pressure, This can prevent the behavior of the mechanical seal device from becoming unstable.

According to the second aspect of the present invention, the floating ring includes a cylindrical main body portion, and a flange portion projecting radially outward from the upper end of the main body portion,
The buttocks are located between the top and bottom of the fixed ring and the rotating ring,
In the open position, the collar portion is locked to the fixed ring from above.

According to this, when the floating ring is lowered to the open position, the collar portion is locked to the stationary ring from above, so that it is possible to prevent the floating ring from dropping from the stationary ring.
The third invention is provided with rotation preventing means for preventing rotation of the floating ring.

According to this, it is possible to prevent co-rotation where the floating ring rotates together with the rotating shaft, and the sealing performance is improved.
The fourth invention is provided in a pump that rotates and feeds an impeller,
A mechanical seal device for sealing a shaft between a rotary shaft for rotating an impeller and a pump casing,
A fixed ring is provided in the shaft hole of the pump casing through which the rotating shaft passes,
A rotary ring is fitted around the rotary shaft in the pump casing,
A floating ring is fitted on the rotating ring and faces below the fixed ring.
An intake / exhaust passage is provided between the lower surface of the stationary ring and the upper surface of the floating ring and communicates with the inside and outside of the pump casing.
The floating ring is movable in a vertical direction over a closed position where it rises to close the intake / exhaust passage and an open position where it descends to open the intake / exhaust passage,
A seal member seals between the outer peripheral surface of the rotating ring and the inner peripheral surface of the floating ring,
In the closed position, the upper surface of the floating ring contacts the lower surface of the stationary ring, and the space between the floating ring and the stationary ring is sealed,
The floating ring is configured to move in the closing direction by the buoyancy of the liquid in the pump casing.

  According to this, when the pump is stopped, the floating ring is lowered to the open position by its own weight, and the intake / exhaust passage is opened. Thereafter, when the pump is started, the rotating ring and the floating ring rotate together with the rotating shaft, the impeller rotates, the liquid is sucked from the suction port, and the liquid level in the pump casing gradually rises. At this time, the air in the pump casing is pushed by the rising liquid level and exhausted to the outside through the intake / exhaust passage.

  When the liquid level further rises, the floating ring rises to the closed position by the buoyancy of the liquid in the pump casing, the intake / exhaust passage is closed, and the upper surface of the floating ring comes into contact with the lower surface of the fixed ring and the lower surface of the fixed ring Slide against. As a result, during pump operation, the upper surface of the floating ring is pressed against the lower surface of the stationary ring by the pressure and buoyancy in the pump casing, the space between the floating ring and the stationary ring is sealed, and the liquid sucked from the suction port The liquid is discharged from the discharge port through the pump casing without leaking from the mechanical seal device.

  Further, when the pump is stopped, the impeller stops rotating and the liquid feeding is stopped, so that the liquid level in the pump casing gradually falls (falls down), the pressure in the pump casing is reduced, and the floating ring is lowered. Since the buoyancy of the liquid acting on the fluid is reduced, the floating ring is lowered to the open position, and the intake / exhaust passage is opened. As a result, external air is sucked into the pump casing through the intake / exhaust passage, and the pressure in the pump casing is maintained at atmospheric pressure without decreasing to a low pressure (negative pressure) below atmospheric pressure. Thus, the liquid level in the pump casing is lowered, and the liquid in the pump casing is smoothly discharged from the suction port to the outside.

Thus, since the mechanical seal device has an intake / exhaust function in addition to the seal function, it is not necessary to separately provide an intake / exhaust device as in the prior art.
In addition, when an air pocket is generated directly under the mechanical seal device during the pump operation, the buoyancy of the liquid acting on the floating ring is reduced by the air pool, so the floating ring is lowered to the open position by its own weight, and the intake / exhaust passage Is opened, and air in the air reservoir is exhausted to the outside of the pump casing through the intake / exhaust passage. As a result, the liquid level in the pump casing rises and the buoyancy of the liquid acting on the floating ring increases, so that the floating ring rises to the closed position by the buoyancy, the intake and exhaust passages are closed, and the upper surface of the floating ring Abuts against the lower surface of the stationary ring and slides relative to the lower surface of the stationary ring, and the space between the floating ring and the stationary ring is sealed. Thereby, there is no air pocket and it is possible to prevent the mechanical seal device from sliding due to being dry and causing a seal failure.

  In addition, when the pump is stopped, the floating ring automatically descends to the open position in conjunction with the drop in the liquid level, so the pump casing does not become a low pressure (negative pressure) below atmospheric pressure, This can prevent the behavior of the mechanical seal device from becoming unstable.

In the fifth invention, the floating ring is engaged with the rotating ring in the circumferential direction by the engaging means.
According to this, when the rotating shaft rotates, the floating ring rotates in the circumferential direction integrally with the rotating shaft together with the rotating ring. As a result, the floating ring does not rotate in the circumferential direction with respect to the rotating ring, and the sealing performance is improved.

The sixth aspect of the invention is provided with a biasing means for biasing the floating ring in the opening direction.
According to this, when the floating ring is lowered to the open position and the air in the pump casing is exhausted through the intake / exhaust passage, the rising speed of the liquid level in the pump casing is fast, and the pressure in the pump casing suddenly increases. Even when the floating ring is raised, the floating ring is biased in the opening direction by the biasing means, so that the floating ring is reliably kept in the open position. Therefore, even if a sudden pressure increase as described above occurs, it is possible to prevent a malfunction such as the floating ring rising and closing the intake / exhaust passage.

  Further, when the pump is stopped and the buoyancy of the liquid acting on the floating ring is reduced, the floating ring is urged in the opening direction by the urging means, so that it is surely lowered from the closed position to the open position. Thereby, it is possible to prevent the trouble that the upper surface of the floating ring does not descend to the open position while adhering to the lower surface of the rotating ring or the stationary ring.

As described above, according to the present invention, since the mechanical seal device has an intake / exhaust function in addition to a seal function, it is not necessary to separately provide an intake / exhaust device as in the prior art.
In addition, if an air pool occurs directly under the mechanical seal device during pump operation, the buoyancy of the liquid acting on the floating ring is reduced by the air pool, so the floating ring is lowered to the open position and the intake / exhaust passage is opened. The air in the air reservoir is exhausted to the outside of the pump casing through the intake / exhaust passage. As a result, the liquid level in the pump casing rises and the buoyancy of the liquid acting on the floating ring increases, so that the floating ring rises to the closed position and the intake / exhaust passage is closed. As a result, there is no air accumulation, and it is possible to prevent the mechanical seal device from sliding in a dry state and causing a seal failure.

  In addition, when the pump is stopped, the floating ring automatically descends to the open position in conjunction with the drop in the liquid level, so the pump casing does not become a low pressure (negative pressure) below atmospheric pressure, This can prevent the behavior of the mechanical seal device from becoming unstable.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, about the same member as the conventional thing mentioned above, the same code | symbol is attached | subjected and description is abbreviate | omitted.
First, a first embodiment will be described with reference to FIGS.

  41 is a mechanical seal device with an intake / exhaust function provided in a portion of the shaft hole 17 formed in the upper part of the pump casing 12. The mechanical seal device 41 has a stationary ring 42, a rotating ring 43, and a floating ring 44. The fixed ring 42 is made of metal and has a cylindrical fitting portion 46 and an annular flange portion 47 provided at the upper end of the fitting portion 46. The fitting portion 46 is fitted into the shaft hole 17 from above, and the flange portion 47 is fixedly attached to the pump casing 12 by a plurality of bolts 48. The fixed ring 42 is provided with an O-ring 49 that seals between the outer peripheral surface of the fitting portion 46 and the inner peripheral surface of the shaft hole 17.

  The rotating shaft 14 has an annular mounting plate 51. The rotating ring 43 is a metal annular member, and is fitted on the rotating shaft 14 and is fixedly mounted on the mounting plate 51 by a plurality of bolts 53 and positioned above the pump casing 12. The rotating ring 43 has a thin layered wear-resistant portion 43a made of a material having excellent wear resistance (for example, carbon or ceramic) on the lower surface thereof.

  The floating ring 44 is made of a material having a specific gravity lighter than water (for example, resin) so that it floats on water. The floating ring 44 extends over the entire circumference from the upper end of the main body 55 to the radially outer side. And an upper collar part 56 and a lower collar part 57 projecting from the lower end of the main body part 55 outward in the radial direction over the entire circumference.

  The main body 55 is disposed between the outer peripheral surface of the rotating shaft 14 and the inner peripheral surface of the fixed ring 42, and is fitted on the inner peripheral surface side of the fixed ring 42. The floating ring 44 is provided with an O-ring 58 (an example of a seal member) that seals between the outer peripheral surface of the main body 55 and the inner peripheral surface of the fixed ring 42. The upper flange 56 is positioned between the upper surface of the fixed ring 42 and the lower surface of the rotating ring 43, the lower flange 57 is positioned below the fitting portion 46 of the fixed ring 42, and the fitting portion 46 is the upper portion. It is fitted between the collar part 56 and the lower collar part 57. The floating ring 44 has a thin layered wear-resistant portion 44a made of a material having excellent wear resistance (for example, carbon or ceramic) on the upper surface thereof.

  The mechanical seal device 41 has an intake / exhaust passage 60 communicating with the inside and the outside of the pump casing 12 at the open position O. The intake / exhaust passage 60 includes a first intake / exhaust passage 60a and a second intake / exhaust passage 60b. The first intake / exhaust passage 60 a is formed over the entire circumference between the lower surface of the rotating ring 43 and the upper surface of the floating ring 44. The second intake / exhaust passage 60 b is formed over the entire circumference between the outer peripheral surface of the rotating shaft 14 and the inner peripheral surface of the floating ring 44. The radially inner end of the first intake / exhaust passage 60a communicates with the upper end of the second intake / exhaust passage 60b, and the radially outer end of the first intake / exhaust passage 60a communicates with the outside of the pump casing 12, The lower ends of the two intake / exhaust passages 60 b communicate with the inside of the pump casing 12.

  The floating ring 44 is lifted to close the first intake / exhaust passage 60a as shown in FIG. 2, and the open position is lowered to open the first intake / exhaust passage 60a as shown in FIG. It can move up and down over O. As shown in FIG. 2, in the closed position S, the upper surface of the floating ring 44 comes into surface contact with the lower surface of the rotating ring 43, and the space between the floating ring 44 and the rotating ring 43 is sealed. As shown in FIG. 1, in the open position O, the upper collar portion 56 is locked to the fixed ring 42 from above, so that the range of movement of the floating ring 44 in the downward direction (opening direction) is restricted.

  A coiled spring 62 (biasing means) for biasing the floating ring 44 downward (opening direction) is provided between the lower end of the fitting portion 46 of the fixed ring 42 and the lower flange portion 57 of the floating ring 44. Example) is provided. As shown in FIG. 4, a plurality of springs 62 are arranged at predetermined intervals in the circumferential direction. Further, the downward total urging force (extension force) of all the springs 62 is set to be smaller than the buoyancy acting on the floating ring 44 by the water in the pump casing 12. Accordingly, the floating ring 44 is configured to overcome the urging force of the spring 62 and rise to the closed position S by the buoyancy.

  The floating ring 44 is prevented from rotating in the circumferential direction by the rotation preventing means 64 while being allowed to move in the vertical direction. The rotation prevention means 64 includes a rotation prevention pin 65 and a rotation prevention hole 66. The rotation prevention pin 65 is provided on the inner peripheral surface of the stationary ring 42, and the rotation prevention hole 66 is formed on the main body 55 of the floating ring 44. It is formed on the outer peripheral surface. As shown in FIG. 3, the rotation stop hole 66 is a long hole that is long in the vertical direction. The distal end portion of the anti-rotation pin 65 is inserted into the anti-rotation hole 66 and can be moved in the vertical direction relative to the anti-rotation hole 66. A plurality of locking pins 65 are provided in the circumferential direction of the fixed ring 42, and a plurality of locking holes 66 are provided in the circumferential direction of the floating ring 44.

Hereinafter, the operation of the above configuration will be described.
When the pump 11 is stopped, as shown in FIG. 1, the floating ring 44 is lowered to the open position O by its own weight and the urging force of the spring 62, and the first intake / exhaust passage 60a is opened. . Thereafter, when the water level in the tank 23 rises to a predetermined drainage start water level and the pump 11 is started, the water in the tank 23 is sucked from the suction port 15 by the rotation of the impeller 13, and the pump casing 12 The water surface W gradually rises. At this time, the air in the pump casing 12 is pushed by the rising water surface W and is exhausted to the outside through the second intake / exhaust passage 60b and the first intake / exhaust passage 60a.

  When the air in the pump casing 12 is exhausted as described above, the floating ring 44 does not move even if the rising speed of the water surface W in the pump casing 12 is fast and the pressure in the pump casing 12 increases rapidly. Since the spring 62 is biased in the opening direction, the spring 62 is reliably maintained in the open position O. Therefore, even if a sudden pressure increase as described above occurs, it is possible to prevent a malfunction such as the floating ring 44 rising and closing the first intake / exhaust passage 60a.

  Further, as the water surface W rises and reaches the floating ring 44, the floating ring 44 floats (rises) to the closed position S by the buoyancy of water in the pump casing 12, as shown in FIG. While the passage 60 a is closed, the upper surface of the floating ring 44 comes into contact with the lower surface of the rotating ring 43 that rotates together with the rotating shaft 14, and the lower surface of the rotating ring 43 slides on the upper surface of the floating ring 44. Thus, during operation of the pump 11, the upper surface of the floating ring 44 is pressed against the lower surface of the rotating ring 43 by the pressure and buoyancy in the pump casing 12, and the space between the floating ring 44 and the rotating ring 43 is sealed, and suction is performed. The water sucked from the port 15 is discharged from the discharge port 16 through the pump casing 12 without leaking from the mechanical seal device 41.

  Further, when the pump 11 is stopped, the rotation of the impeller 13 is stopped and the water supply is stopped, so that the water surface W in the pump casing 12 is gradually lowered (falls down), and the pressure in the pre-casing 12 is reduced. At the same time, since the buoyancy acting on the floating ring 44 is reduced, as shown in FIG. 1, the floating ring 44 is lowered to the open position O, and the first intake / exhaust passage 60a is opened. As a result, external air is sucked into the pump casing 12 through the first intake / exhaust passage 60a and the second intake / exhaust passage 60b, and the pressure in the pump casing 12 is reduced to a low pressure (negative pressure) lower than atmospheric pressure. The water level W in the pump casing 12 is lowered while the pressure is maintained at the atmospheric pressure without decreasing the pressure, and the water in the pump casing 12 is smoothly discharged from the suction port 15 to the outside. At this time, since the floating ring 44 is urged in the opening direction by the spring 62, it is surely lowered from the closed position S to the open position O. Thereby, it is possible to prevent the trouble that the upper surface of the floating ring 44 is not lowered to the open position O while the upper surface is attached to the lower surface of the rotating ring 43.

Thus, since the mechanical seal device 41 has an intake / exhaust function in addition to the seal function, it is not necessary to separately provide the intake / exhaust device 20 (see FIG. 11) as in the prior art.
In addition, when an air pocket is generated immediately below the mechanical seal device 41 during the operation of the pump 11, the buoyancy of water acting on the floating ring 44 is reduced by the air pool. Therefore, as shown in FIG. Is lowered to the open position O by its own weight and the urging force of the spring 62, the first intake / exhaust passage 60a is opened, and air in the air pocket passes through the second intake / exhaust passage 60b and the first intake / exhaust passage 60a. Exhausted to the outside.

  As a result, the water surface W in the pump casing 12 rises and the buoyancy of water acting on the floating ring 44 increases, so that the floating ring 44 rises to the closed position S by the buoyancy as shown in FIG. 1 is closed, the upper surface of the floating ring 44 comes into contact with the lower surface of the rotating ring 43 that rotates together with the rotary shaft 14, and the lower surface of the rotating ring 43 slides against the upper surface of the floating ring 44. The space between the floating ring 44 and the rotating ring 43 is sealed. Thereby, there is no air pocket and it can prevent that the mechanical seal apparatus 41 slides in a dry state and a seal defect is caused.

  Further, when the pump 11 is stopped, the floating ring 44 is automatically lowered to the open position O in conjunction with the decrease (falling water) of the water surface W, so that the pump casing 12 has a low pressure (negative pressure) less than atmospheric pressure. ), And the behavior of the mechanical seal device 41 can be prevented from becoming unstable.

Moreover, since the front-end | tip part of the non-rotating pin 65 is inserted in the non-rotating hole 66, the corotation which the floating ring 44 rotates with the rotating shaft 14 can be prevented, and a sealing performance improves.
Further, as shown in FIG. 1, when the floating ring 44 is lowered to the open position O, the upper collar portion 56 is locked to the fixed ring 42 from above, so that the floating ring 44 is dropped from the fixed ring 42. Can be prevented.

  As shown in FIG. 2, when the floating ring 44 is raised to the closed position S, the lower surface of the rotating ring 43 and the upper surface of the floating ring 44 slide on each other as a sealing surface. Since it is comprised by the wear parts 43a and 44a, it is hard to wear out and endures long-term use.

  In the first embodiment, a plurality of anti-rotation pins 65 and anti-rotation holes 66 are provided, but one may be provided. Further, the anti-rotation pin 65 may be provided in the floating ring 44, and the anti-rotation hole 66 may be provided in the fixed ring 42.

Next, a second embodiment will be described with reference to FIGS.
The rotation prevention means 75 includes a rotation prevention bolt 76 and a rotation prevention hole 77, the rotation prevention bolt 76 is provided at the lower end of the fitting portion 46 of the fixed ring 42, and the rotation prevention hole 77 is a lower part of the floating ring 44. It is formed in the collar part 57. The anti-rotation hole 77 penetrates up and down, and the anti-rotation bolt 76 is inserted into the anti-rotation hole 77 and the spring 62 from below, so that the anti-rotation hole 77 moves in the vertical direction relative to the anti-rotation hole 77. It is possible. A plurality of locking bolts 76 are provided in the circumferential direction of the stationary ring 42, and a plurality of locking holes 77 are provided in the circumferential direction of the floating ring 44.

According to this, since the non-rotating bolt 76 is inserted into the non-rotating hole 77, it is possible to prevent the floating ring 44 from rotating together with the rotating shaft 14.
In the second embodiment, a plurality of the non-rotating bolts 76 and the non-rotating holes 77 are provided, but one each may be provided. Further, although the rotation prevention bolt 76 is inserted through the spring 62, the rotation prevention bolt 76 may be arranged at a position shifted in the circumferential direction from the position of the spring 62.

Next, a third embodiment will be described with reference to FIGS.
The mechanical seal device 81 has a stationary ring 42, a rotating ring 43, and a floating ring 44. The fixed ring 42 has a fitting portion 46 and a flange portion 47. The fitting portion 46 is fitted into the shaft hole 17 from above, and the flange portion 47 is fixedly attached to the pump casing 12 by a plurality of bolts 48. The fixed ring 42 is provided with an O-ring 49 that seals between the outer peripheral surface of the fitting portion 46 and the inner peripheral surface of the shaft hole 17. The stationary ring 42 has a thin layered wear-resistant portion 42a made of a material having excellent wear resistance (for example, carbon or ceramic) on the lower surface thereof.

The rotating ring 43 is a metal ring-shaped member, and is externally fitted to the rotating shaft 14 and attached by welding or the like in the pump casing 12.
The floating ring 44 is made of a material having a specific gravity lighter than water (for example, resin) so as to float on water, and is externally fitted to the rotating ring 43 so as to face below the fixed ring 42. The floating ring 44 includes a cylindrical main body portion 83, an upper collar portion 84 projecting from the upper end of the main body portion 83 to the radially inner side, and a lower portion projecting from the lower end of the main body portion 83 to the radially inner side. And a flange portion 85. The main body portion 83 is located on the outer side in the radial direction of the rotating ring 43, the upper flange portion 84 is positioned between the upper and lower sides of the fixed ring 42 and the rotating ring 43, and the lower flange portion 85 is positioned below the rotating ring 43. .

  The rotating ring 43 is provided with an O-ring 87 (an example of a sealing member) that seals between the outer peripheral surface of the rotating ring 43 and the inner peripheral surface of the main body 83 of the floating ring 44. The floating ring 44 has a thin layered wear-resistant portion 44a made of a material having excellent wear resistance (for example, carbon or ceramic) on the upper surface thereof.

  The mechanical seal device 81 has an intake / exhaust passage 60 communicating with the inside and the outside of the pump casing 12 at the open position O. The intake / exhaust passage 60 includes a first intake / exhaust passage 60a and a second intake / exhaust passage 60b. The first intake / exhaust passage 60 a is formed over the entire circumference between the lower surface of the fixed ring 42 and the upper surface of the floating ring 44. The second intake / exhaust passage 60b is formed over the entire circumference between the outer peripheral surface of the rotating shaft 14 and the inner peripheral surface of the stationary ring 42. The radially inner end of the first intake / exhaust passage 60a communicates with the lower end of the second intake / exhaust passage 60b, the radially outer end of the first intake / exhaust passage 60a communicates with the inside of the pump casing 12, The upper ends of the two intake / exhaust passages 60 b communicate with the upper outside of the pump casing 12.

  The floating ring 44 is raised to close the first intake / exhaust passage 60a as shown in FIG. 8, and the open position is lowered to open the first intake / exhaust passage 60a as shown in FIG. It can move up and down over O. As shown in FIG. 8, in the closed position S, the upper surface of the floating ring 44 comes into surface contact with the lower surface of the stationary ring 42, and the space between the floating ring 44 and the stationary ring 42 is sealed. Further, as shown in FIG. 7, at the open position O, the upper collar portion 84 is locked to the rotary ring 43 from above, so that the range of movement of the floating ring 44 in the downward direction (opening direction) is restricted.

  In addition, a coiled spring 62 (an example of a biasing means) that biases the floating ring 44 downward (opening direction) is provided between the rotating ring 43 and the lower flange portion 85 of the floating ring 44. Yes. As shown in FIG. 9, a plurality of springs 62 are arranged at predetermined intervals in the circumferential direction. Further, the downward total urging force (extension force) of all the springs 62 is set to be smaller than the buoyancy acting on the floating ring 44 by the water in the pump casing 12. Accordingly, the floating ring 44 is configured to overcome the urging force of the spring 62 and rise to the closed position S by the buoyancy.

  The floating ring 44 is engaged with the rotating ring 43 in the circumferential direction while being allowed to move in the vertical direction by the engaging means 88. The engaging means 88 includes an engaging pin 89 and an engaging hole 90, and the engaging pin 89 is provided on the outer peripheral surface of the rotating ring 43, and the engaging hole 90 is located inside the main body 83 of the floating ring 44. It is formed on the peripheral surface. As shown in FIG. 10, the engagement hole 90 is a long hole that is long in the vertical direction. The distal end portion of the engagement pin 89 is inserted into the engagement hole 90 and can move in the vertical direction relative to the engagement hole 90. A plurality of engagement pins 89 are provided in the circumferential direction of the rotating ring 43, and a plurality of engagement holes 90 are provided in the circumferential direction of the floating ring 44.

Hereinafter, the operation of the above configuration will be described.
When the pump 11 is stopped, as shown in FIG. 7, the floating ring 44 is lowered to the open position O by its own weight and the urging force of the spring 62, and the first intake / exhaust passage 60a is opened. . After that, when the water level in the tank 23 rises to a predetermined drainage start water level and the pump 11 is started, the rotating ring 43 and the floating ring 44 rotate together with the rotating shaft 14, and the impeller 13 rotates, The water in 23 is sucked from the suction port 15, and the water surface W in the pump casing 12 gradually rises. At this time, the air in the pump casing 12 is pushed by the rising water surface W and exhausted to the outside through the first intake / exhaust passage 60a and the second intake / exhaust passage 60b.

  When the air in the pump casing 12 is exhausted as described above, the floating ring 44 does not move even if the rising speed of the water surface W in the pump casing 12 is fast and the pressure in the pump casing 12 increases rapidly. Since the spring 62 is biased in the opening direction, the spring 62 is reliably maintained in the open position O. Therefore, even if a sudden pressure increase as described above occurs, it is possible to prevent a malfunction such as the floating ring 44 rising and closing the first intake / exhaust passage 60a.

  When the water surface W further rises and reaches the floating ring 44, the floating ring 44 floats (rises) to the closed position S due to the buoyancy of water in the pump casing 12, as shown in FIG. While the passage 60 a is closed, the upper surface of the floating ring 44 comes into contact with the lower surface of the stationary ring 42 and slides with respect to the lower surface of the stationary ring 42. As a result, during operation of the pump 11, the upper surface of the floating ring 44 is pressed against the lower surface of the stationary ring 42 by the pressure and buoyancy in the pump casing 12, and the space between the floating ring 44 and the stationary ring 42 is sealed. The water sucked from the port 15 is discharged from the discharge port 16 through the pump casing 12 without leaking from the mechanical seal device 81.

  Further, when the pump 11 is stopped, the rotation of the impeller 13 is stopped and the water supply is stopped, so that the water surface W in the pump casing 12 is gradually lowered (falls down), and the pressure in the pre-casing 12 is reduced. At the same time, since the buoyancy acting on the floating ring 44 is reduced, as shown in FIG. 7, the floating ring 44 is lowered to the open position O, and the first intake / exhaust passage 60a is opened. As a result, external air is sucked into the pump casing 12 through the second intake / exhaust passage 60b and the first intake / exhaust passage 60a, and the pressure in the pump casing 12 is reduced to a low pressure (negative pressure) lower than atmospheric pressure. The water level W in the pump casing 12 is lowered while the pressure is maintained at the atmospheric pressure without decreasing the pressure, and the water in the pump casing 12 is smoothly discharged from the suction port 15 to the outside. At this time, since the floating ring 44 is urged in the opening direction by the spring 62, it is surely lowered from the closed position S to the open position O. Accordingly, it is possible to prevent the trouble that the upper surface of the floating ring 44 does not descend to the open position O while the upper surface of the floating ring 44 is attached to the lower surface of the stationary ring 42.

Thus, since the mechanical seal device 81 has an intake / exhaust function in addition to the seal function, there is no need to separately provide the intake / exhaust device 20 (see FIG. 11) as in the prior art.
Further, when an air pool is generated immediately below the mechanical seal device 81 during the operation of the pump 11, the buoyancy of water acting on the floating ring 44 is reduced by the air pool. Therefore, as shown in FIG. Is lowered to the open position O by its own weight and the urging force of the spring 62, the first intake / exhaust passage 60a is opened, and the air in the air pocket passes through the first intake / exhaust passage 60a and the second intake / exhaust passage 60b. Exhausted to the outside.

  As a result, the water surface W in the pump casing 12 rises and the buoyancy of water acting on the floating ring 44 increases, so that the floating ring 44 rises to the closed position S by the buoyancy as shown in FIG. 1 is closed, the upper surface of the floating ring 44 is in contact with the lower surface of the stationary ring 42 and slides against the lower surface of the stationary ring 42, and the space between the floating ring 44 and the stationary ring 42 is sealed. Is done. Thereby, there is no air pocket and it is possible to prevent the mechanical seal device 81 from sliding in a dry state and causing a seal failure.

  Further, when the pump 11 is stopped, the floating ring 44 is automatically lowered to the open position O in conjunction with the decrease (falling water) of the water surface W, so that the pump casing 12 has a low pressure (negative pressure) less than atmospheric pressure. In this way, it is possible to prevent the behavior of the mechanical seal device 81 from becoming unstable.

  Further, since the floating ring 44 is engaged with the rotating ring 43 in the circumferential direction by the engaging means 88, when the rotating shaft 14 rotates, the floating ring 44 is integrated with the rotating shaft 14 together with the rotating shaft 14 in the circumferential direction. Rotate to. Thereby, the floating ring 44 does not rotate with respect to the rotating ring 43 in the circumferential direction, and the sealing performance is improved.

  Further, as shown in FIG. 7, when the floating ring 44 is lowered to the open position O, the upper collar portion 84 is locked to the rotating ring 43 from above, so that the floating ring 44 is dropped from the rotating ring 43. Can be prevented.

  As shown in FIG. 8, when the floating ring 44 is raised to the closed position S, the lower surface of the stationary ring 42 and the upper surface of the floating ring 44 slide with each other as a seal surface. Since it is comprised by the wear parts 42a and 44a, it is hard to wear out and endures long-term use.

  In the third embodiment, a plurality of engagement pins 89 and a plurality of engagement holes 90 are provided, but one may be provided. Further, the engaging pin 89 may be provided in the floating ring 44 and the engaging hole 90 may be provided in the rotating ring 43.

In each of the above embodiments, the spring 62 is used as an example of the urging means, but an elastic body such as rubber may be used.
In each of the above embodiments, the floating ring 44 is made of a material having a specific gravity lighter than water (for example, resin) and floats on water. However, the floating ring 44 is made hollow to float on water. May be. Further, a floating body may be provided on the floating ring 44 so as to float on water.

In each of the embodiments described above, water is used as an example of the liquid, but is not limited to water.
In each of the above embodiments, the vertical shaft mixed flow pump 11 has been described as an example of the pump, but another axial flow pump or mixed flow pump may be used.

It is sectional drawing of the mechanical seal apparatus in the 1st Embodiment of this invention, and shows the state at the time of supply / exhaust. It is sectional drawing of a mechanical seal apparatus similarly and shows the state at the time of sealing. It is a side view of the floating ring of the mechanical seal device. It is a top view of the floating ring of a mechanical seal apparatus equally. It is sectional drawing of the mechanical seal apparatus in the 2nd Embodiment of this invention, and shows the state at the time of supply / exhaust. It is sectional drawing of a mechanical seal apparatus similarly and shows the state at the time of sealing. It is sectional drawing of the mechanical seal apparatus in the 3rd Embodiment of this invention, and shows the state at the time of supply / exhaust. It is sectional drawing of a mechanical seal apparatus similarly and shows the state at the time of sealing. It is a XX arrow line view in FIG. It is a longitudinal cross-sectional view of the floating ring of the mechanical seal device. It is sectional drawing of the vertical-shaft mixed flow pump provided with the conventional mechanical seal apparatus.

Explanation of symbols

11 Vertical shaft mixed flow pump 12 Pump casing 13 Impeller 14 Rotating shaft 17 Shaft hole 41 Mechanical seal device 42 Fixed ring 43 Rotating ring 44 Floating ring 55 Main body 56 Upper flange 58 O-ring (seal member)
60 Intake / exhaust passage 62 Spring (biasing means)
64, 75 Anti-rotation means 81 Mechanical seal device 88 Engaging means O Open position S Closed position

Claims (6)

Provided in the pump that rotates and feeds the impeller,
A mechanical seal device for sealing a shaft between a rotary shaft for rotating an impeller and a pump casing,
A fixed ring is provided in the shaft hole of the pump casing through which the rotating shaft passes,
A rotating ring is fitted around the rotating shaft,
A floating ring is arranged between the stationary ring and the rotating shaft,
An intake / exhaust passage is provided between the lower surface of the rotary ring and the upper surface of the floating ring and communicates with the inside and the outside of the pump casing,
The floating ring is movable in a vertical direction over a closed position where it rises to close the intake / exhaust passage and an open position where it descends to open the intake / exhaust passage,
The space between the inner peripheral surface of the stationary ring and the outer peripheral surface of the floating ring is sealed with a seal member,
In the closed position, the upper surface of the floating ring contacts the lower surface of the rotating ring, and the space between the floating ring and the rotating ring is sealed,
A mechanical seal device, wherein the floating ring is configured to move in a closing direction by buoyancy of liquid in a pump casing. The floating ring includes a cylindrical main body part and a collar part protruding radially outward from the upper end of the main body part,
The buttocks are located between the top and bottom of the fixed ring and the rotating ring,
The mechanical seal device according to claim 1, wherein the flange portion is locked to the fixed ring from above in the open position. The mechanical seal device according to claim 1 or 2, further comprising a rotation prevention means for preventing the rotation of the floating ring. Provided in the pump that rotates and feeds the impeller,
A mechanical seal device for sealing a shaft between a rotary shaft for rotating an impeller and a pump casing,
A fixed ring is provided in the shaft hole of the pump casing through which the rotating shaft passes,
A rotary ring is fitted around the rotary shaft in the pump casing,
A floating ring is fitted on the rotating ring and faces below the fixed ring.
An intake / exhaust passage is provided between the lower surface of the stationary ring and the upper surface of the floating ring and communicates with the inside and outside of the pump casing.
The floating ring is movable in a vertical direction over a closed position where it rises to close the intake / exhaust passage and an open position where it descends to open the intake / exhaust passage,
A seal member seals between the outer peripheral surface of the rotating ring and the inner peripheral surface of the floating ring,
In the closed position, the upper surface of the floating ring contacts the lower surface of the stationary ring, and the space between the floating ring and the stationary ring is sealed,
A mechanical seal device, wherein the floating ring is configured to move in a closing direction by buoyancy of liquid in a pump casing. The mechanical seal device according to claim 4, wherein the floating ring is engaged with the rotating ring in the circumferential direction by the engaging means. The mechanical seal device according to any one of claims 1 to 5, further comprising an urging unit that urges the floating ring in an opening direction.

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