JP6430326B2 - Hydrostatic mechanical seal device - Google Patents

Description

  The present invention relates to a hydrostatic mechanical seal device that slides in a non-contact state by introducing and ejecting a pressure fluid between sliding surfaces from outside the device to create a gap between the sliding surfaces.

  2. Description of the Related Art Conventionally, in a mechanical seal device, a static pressure type mechanical seal device has been used in order to suppress leakage of a sealed fluid in the machine to the outside of the machine or to suppress generation of contamination.

  For example, a force (separation force) acting in a direction to separate the opposing sliding surfaces by introducing a high-pressure seal gas into the sliding surface of the stationary seal ring and ejecting between the sliding surfaces, and the stationary seal ring By sliding the pressurized fluid into the back pressure chamber on the back of the balance, the force (approaching force) acting in the direction to bring the sliding surfaces closer to each other is balanced, creating a gap between the opposing sliding surfaces, and sliding There has been proposed a static pressure type mechanical seal device that prevents the sealed fluid from leaking out of the apparatus while the surfaces are not in contact with each other.

  Further, it has been proposed to introduce the sealed fluid in the machine into the back pressure chamber of the stationary side sealing ring and obtain the approach force by the pressure of the sealed fluid. (For example, refer to [0009] of Patent Document 1 and FIG. 1.)

  In addition, a sealing gas is introduced into the back pressure chamber of the stationary side sealing ring, and the approaching force is obtained by the pressure of the sealing gas, and the shape of the stationary side sealing ring, the shape of the housing, the arrangement position of the O-ring, etc. It has been proposed to change the approach force by changing the shape of the back pressure chamber. (For example, see [0032] of Patent Document 2 and FIGS. 1 and 2)

JP-A-4-224373 ([0009], FIG. 1) JP 2006-105365 A ([0032], FIGS. 1 and 2)

  In Patent Document 1, since the sealed fluid in the machine is used as the fluid guided to the back pressure chamber of the stationary side sealing ring, the sealed fluid also comes into contact with a member such as a housing forming the back pressure chamber. Therefore, it is necessary to make all the members that come into contact with the sealed fluid a material corresponding to the sealed fluid, for example, a corrosion-resistant material.

  On the other hand, in Patent Document 2, since a sealing gas is used as a fluid guided to the back pressure chamber of the stationary-side sealing ring, there is no problem in material of members such as a housing forming the back pressure chamber as described above. .

  However, in Patent Document 2, it is necessary to change the shape of the stationary seal ring, the shape of the housing, the arrangement position of the O-ring, etc. in order to change the approach force. It is necessary to prepare a ring and a housing. In addition, since the back pressure chamber is a space sealed by an O-ring, when the supply side of the seal gas becomes abnormally high, the back pressure chamber increases in pressure according to the pressure on the supply side. Since most of the introduced sealing gas is released to the outside, the pressure between the sliding surfaces does not increase so much. For this reason, when the supply side of the seal gas becomes abnormally high in pressure, the approaching force acting on the stationary seal ring is relatively high, which may adversely affect the sealing performance.

  The present invention has been made paying attention to such problems, and an object of the present invention is to provide a static pressure type mechanical seal device that is less affected by pressure change on the supply side of the pressurized fluid and can cope with various specifications. .

In order to solve the above problems, the static pressure mechanical seal device of the present invention is:
A hydrostatic mechanical seal device that seals between a housing and a rotating shaft and introduces and ejects a pressure fluid between sliding surfaces.
A rotating side sealing ring that rotates together with the rotating shaft;
A stationary side sealing ring provided opposite to the rotation side sealing ring and having a supply path for supplying the pressure fluid between the sliding surfaces;
A back pressure chamber formed on the opposite side of the sliding surface of the stationary side sealing ring by the housing and the stationary side sealing ring, and pressure fluid is supplied from an inflow hole;
And a pressure adjusting unit that adjusts the pressure in the back pressure chamber by allowing the pressure fluid in the back pressure chamber to flow out.
According to this feature, the pressure adjusting unit can flow the pressure fluid in the back pressure chamber to the outside to obtain the desired pressure, and the pressing force on the sliding surface due to the pressure on the back surface of the sealing ring can be reduced to the desired force. Can be adjusted. Even if the pressure on the supply side of the pressurized fluid becomes high, the influence is small. Furthermore, various specifications can be accommodated by adjusting / changing the pressure adjusting unit.

The inflow hole is provided with a throttle.
According to this feature, since the throttle is provided in the inflow hole, the pressure fluid does not flow suddenly into the back pressure chamber even if the pressure fluid pressure on the supply side suddenly rises, and the pressure in the back pressure chamber rises rapidly. There is nothing to do.

It has a branch chamber which branches the pressure fluid into the supply path and the inflow hole.
According to this feature, since the same pressure fluid is supplied from the branch chamber to the supply path and the back pressure chamber, not only a separate pressure fluid supply source is required, but also a pressure fluid that creates a gap between the sliding surfaces. Since the pressure fluid from the same pressure fluid supply source is supplied and the pressure is adjusted by the pressure adjusting unit to obtain the desired pressure in the back pressure chamber, the structure is simplified.

The pressure adjusting unit is a pressure regulator that is detachably provided on the housing or the stationary side sealing ring.
According to this feature, since the pressure regulator can be attached to and detached from the housing or the stationary side sealing ring, the structure of the stationary side sealing ring and the housing is changed by using a pressure regulator of a pressure adjustment amount according to the application. There is no need. For this reason, the design freedom of the shape of the back pressure chamber formed by the stationary side sealing ring and the housing is high.

A discharge path for discharging the fluid leaking from between the sliding surfaces and the pressure fluid flowing out of the pressure adjusting unit is provided.
According to this feature, the fluid leaking from between the sliding surfaces merges with the pressure fluid flowing out from the pressure adjusting unit and is discharged, so the flow path of the fluid leaking from between the sliding surfaces and the pressure adjusting unit flows out. There is no need to provide a separate flow path for the fluid to be used. Compared to the case where a separate flow path is provided, the processing work is saved, the strength of the housing is not reduced, and the housing is large in order to secure the flow path. Furthermore, even if the fluid leaking from between the sliding surfaces contains a fluid to be sealed other than the pressure fluid, the fluid to be sealed can be diluted with the pressure fluid.

It is sectional drawing which shows the static pressure type mechanical seal apparatus in Example 1. FIG. It is sectional drawing which shows the principal part of FIG. 6 is a cross-sectional view showing a main part of Example 2. FIG.

  EMBODIMENT OF THE INVENTION The form for implementing the static pressure type mechanical seal apparatus which concerns on this invention is demonstrated below based on an Example.

  The hydrostatic mechanical seal device according to the first embodiment will be described with reference to FIGS. 1 and 2. In the following description, the center line of the rotating shaft in FIG. 1 is described as the axial direction, the direction extending radially from the center line is the radial direction, and the direction along the same distance from the center line is the circumferential direction. In FIGS. 1 and 2, a member having a substantially oval cross section or a stadium shape is a secondary seal such as an O-ring.

  Referring to FIG. 1, a static pressure type mechanical seal device 100 mainly includes a rotary side seal ring 10, a static side seal ring 20, a housing 30, a pressure fluid path 40, and a pressure fluid 60. The fluid to be sealed in the machine interior M is sealed by the cooperation of the rotating side sealing ring 10 and the stationary side sealing ring 20.

The rotation-side sealing ring 10 is attached to the rotation shaft 1 so as to be integrally rotatable by a holder 11 and a sleeve 12. The rotation-side sealing ring 10 is made of SiC, Al ₂ O ₃ or the like.

  The stationary side sealing ring 20 is arranged opposite to the rotation side sealing ring 10 and is pressed in the axial direction by a spring 21 accommodated in a recess of the housing 30. A knock pin 22 fixed to the housing 30 is inserted into the concave groove 23 of the stationary side sealing ring 20. Thereby, the stationary side sealing ring 20 is attached so as to be movable in the axial direction and not to rotate in the circumferential direction. The number of springs 21 and knock pins 22 is not limited, but a plurality of springs 21 and knock pins 22 may be equally provided in the circumferential direction. The stationary seal ring 20 is made of SiC or C. The spring 21 has a pressing force for pressing the stationary seal ring 20 against the rotary seal ring 10 in a sealed state when the device is not used, that is, when the pressure of the back pressure chamber 49 described later is substantially atmospheric pressure. Should be selected.

  The housing 30 is mainly composed of a housing body 31 and an annular case 32 to which the stationary side sealing ring 20 is attached on the inner periphery. The housing body 31 and the case 32 are made of a metal material such as stainless steel. A bush 33 made of PTFE or the like is attached to the end of the housing body 31 on the atmosphere side A by bolts and a mounting plate 34. A space defined by the outer peripheral surface of the sleeve 12 and the inner peripheral surface of the housing body 31 is sealed with respect to the atmosphere side A (the right side in the axial direction in FIG. 1) by the bush 33. The attachment plate 34 and the sleeve 12 are attached in a non-contact state.

  The pressure fluid path 40 mainly includes a supply side channel 41 that supplies the pressure fluid 60 and a discharge side channel 51 that discharges the pressure fluid 60. A pressure fluid supply device 2 (pressure fluid supply source) is connected to the supply side flow path 41 via the supply pipe 3 on the outer periphery in the radial direction of the housing body 31, and the discharge pipe 4 is connected to the discharge side flow path 51. A recovery container 5 is connected via the connector. The pressure fluid supply device 2 has a pump, for example, and discharges the pressure fluid 60 having a constant pressure.

  With reference to FIG. 2, the supply-side flow path 41 is formed inside the housing 30 formed by the hole 42 extending radially inward from the outer periphery of the housing body 31, the housing body 31 and the case 32, and communicating with the hole 42. A branch hole 43 formed in the case 32 and communicating with the branch chamber 43, and a through hole 46 formed in the stationary-side sealing ring 20 and communicating with the through hole 44. A first throttle 45 is provided on the upstream side of the through hole 46, and the downstream side of the through hole 46 faces the sliding surface of the rotation-side sealing ring 10. Further, on the downstream side of the through hole 46, a groove extending along the sliding surface is provided so as to continue to the through hole 46. The rotation-side seal ring 10 is also provided with a groove extending along the sliding surface at a position facing the groove. The grooves provided on these sliding surfaces have a well-known configuration, and the shape and size can be determined as appropriate. A flow path formed by the hole 42 and the branch chamber 43 is referred to as a first flow path 61. The second flow path formed by the branch chamber 43, the through hole 44 and the through hole 46 is referred to as a supply path 62.

  The supply-side flow path 41 has a branch path 64 that is a fourth flow path that branches from the branch chamber 43. The branch path 64 is formed by an inflow hole 48 formed in the case 32 and communicating with the branch chamber 43, and a back pressure chamber 49 formed by the stationary side sealing ring 20, the housing body 31, and the case 32 and communicating with the inflow hole 48. ing. A second restrictor 47 is provided in the inflow hole 48.

  The discharge-side flow path 51 is formed to extend in the axial direction in the housing body 31 and communicate with the back pressure chamber 49, and is formed to extend in the radial direction in the housing body 31 and communicates with the through-hole 53. A through hole 54 is provided. The through hole 53 is provided with a third throttle 52 (pressure adjusting unit). The above-described discharge pipe 4 is connected to one end on the radially outer side of the through hole 54. In addition, the other end of the through hole 54 communicates with a discharge chamber 55 formed by the rotation-side sealing ring 10, the stationary-side sealing ring 20, the sleeve 12, the housing body 31, and the bush 33. A flow path extending between the sliding surfaces to the discharge chamber 55 is referred to as a third flow path 63, a flow path passing through the through hole 53 is referred to as a fifth flow path 65, and a sixth flow path passing through the through hole 54 is referred to as a discharge path 66.

  Here, the flow of the pressure fluid 60 in the housing 30 will be briefly described. The pressurized fluid 60 supplied to the first flow path 61 is branched and supplied to the supply path 62 and the branch path 64 in the branch chamber 43. Fluids from the third flow path 63 and the fifth flow path 65 are merged and discharged from the discharge path 66 to the outside.

Here, the first restrictor 45, the second restrictor 47, and the third restrictor 52 are fixed restrictors that adjust the pressure to a predetermined value, and the outer periphery thereof is sealed in the through hole 46, the inflow hole 48, and the through hole 53, respectively. It is provided in the state.
Further, the pressure fluid 60 is slightly higher in pressure than the sealed fluid in the machine interior M. It is preferable to use a pressure fluid 60 that is harmless to the human body or the static pressure mechanical seal device 100, such as nitrogen gas.

When the device is in operation, the rotary shaft 1 is rotated, and the pressure fluid 60 passes through the through hole 46 between the sliding surface of the rotating side sealing ring 10 and the sliding surface of the stationary side sealing ring 20 (also simply referred to as between the sliding surfaces). ) And a separation force F <b> 1 that separates the sliding surfaces is generated in the stationary seal ring 20. On the other hand, the stationary seal ring 20, approaching force F2 is a resultant force of the forces caused by the pressure P ₄₉ in the pressing force to the back pressure chamber 49 of the spring 21 acts.

The tension of the spring 21, the cross-sectional area (projected area) of the stationary seal ring 20 facing the back pressure chamber 49, the pressure P _{S of the} pressure fluid supplied between the sliding surfaces, so that the separation force F1> the approach force F2 The pressure P ₄₉ of the back pressure chamber 49 is set. Thereby, the separation force F1 and the approach force F2 are balanced, and the sliding surfaces are maintained in a non-contact state with an intended gap maintained. In this state, the fluid to be sealed is sealed by forming a static pressure fluid film between the sliding surfaces.

Since the first aperture 45 provided in the supply passage 62, between the sliding surfaces becomes narrow and increases the pressure P _S in the through hole 46 during operation of the apparatus, to force acts trying Hanaso between sliding surfaces. Conversely, the lower the pressure P _S in the through hole 46 between the sliding surfaces is widened, to force acts attempts tend to bring said between sliding surfaces. In this way, the desired gap is maintained between the sliding surfaces.

Since the pressure fluid 60 in the back pressure chamber 49 which is released into the through-hole 54 through the third aperture 52 (outside), it is possible to make the back pressure chamber 49 with the desired pressure P _49. That is, it suppressed the pressure P ₄₉ in the back pressure chamber 49 becomes too high. For example, when the pressure fluid supply device 2 becomes abnormal and the pressure P _{43 in} the branch chamber 43 becomes abnormally high, the pressure P _{49 in the} back pressure chamber ₄₉ also increases, but the pressure fluid 60 passes through the third throttle 52. Since it escapes to the hole 54, it does not rise excessively and the approach force F2 does not become excessive. On the other hand, when the back pressure chamber 49 is formed in a sealed space as in the prior art, the fluid in the back pressure chamber 49 accumulates without being discharged, so that the pressure rises excessively and the approach force F2 becomes the separation force F1. Is significantly larger than For this reason, the desired gap between the sliding surfaces cannot be maintained, and the sealing performance may be adversely affected.

Further, by changing the third diaphragm 52, the first aperture 45 if necessary, by also changing the second diaphragm 47, it is possible to change the desired pressure P ₄₉ to maintain the back pressure chamber 49 It can correspond to various specifications. That is, there is no need to change the structure of the stationary seal ring 20, the housing body 31, and the case 32, and the degree of freedom in designing the shape of the back pressure chamber 49 formed by the stationary seal ring 20, the housing body 31, and the case 32. Is expensive.

  Further, since the first diaphragm 45, the second diaphragm 47, and the third diaphragm 52 are fixed diaphragms, the pressure can be set to an intended value. Furthermore, if the first diaphragm 45, the second diaphragm 47, and the third diaphragm 52 are detachable, it is easier to change the diaphragm amount.

  Further, since the same pressure fluid 60 is supplied to the supply passage 62 and the back pressure chamber 49 because the branch passage 64 is provided, the individual pressure fluid supply device 2 becomes unnecessary, and the structure is simplified. Further, the pressure fluid 60 from the same pressure fluid supply device 2 as the pressure fluid 60 causing a gap between the sliding surfaces is supplied, and the pressure is adjusted by the third restriction 52 to the back pressure chamber 49. Since the pressure can be obtained, the structure becomes simple.

  Further, the fluid leaking from between the sliding surfaces is mixed with the pressure fluid 60 flowing out from the third throttle 52 and the through hole 54 and is discharged to the collection container 5. For this reason, even if the fluid leaking from between the sliding surfaces contains a sealed fluid other than the pressure fluid 60, the fluid containing the sealed fluid can be diluted with the pressure fluid 60. For example, even if the sealed fluid is a corrosive fluid, the corrosivity can be reduced by dilution. Further, since the bush 33 is arranged on the inner periphery of the housing body 31 and the discharge chamber 55 is formed in the vicinity of the back pressure chamber 49 and the through hole 54, the housing body 31 can be configured compactly.

  Furthermore, when used in a form in which the sealed fluid does not leak from between the sliding surfaces, the fluid that leaks from between the sliding surfaces is only the pressure fluid 60, and the fluid discharged from the through hole 54 is only the pressure fluid 60. Therefore, the recovered fluid can be reused as the pressure fluid 60.

  Next, a hydrostatic mechanical seal device according to Example 2 will be described with reference to FIG. The second embodiment is mainly different from the first embodiment in that the second diaphragm 47 is not provided. In addition, the same structure as Example 1 and the overlapping structure are abbreviate | omitted.

As shown in FIG. 3, the branch path 64 of the supply-side channel 41 includes an inflow hole 48 ′ formed in the case 32 and communicating with the branch chamber 43 from the branch chamber 43, the stationary-side sealing ring 20, the housing body 31, The back pressure chamber 49 is formed by the case 32 and communicates with the inflow hole 48 ′. Because they are connected by no inflow hole 48 'to stop distributing chamber 43 and the back pressure chamber 49 is substantially equal to the pressure P ₄₉ in the pressure P ₄₃ and the back pressure chamber 49 of the distributing chamber 43. With this configuration, it is possible to ensure a high pressure P ₄₉ in the back pressure chamber 49 when using the device, it is possible to obtain a large approaching force F2.

  Although the embodiments of the present invention have been described with reference to the drawings, the specific configuration is not limited to these embodiments, and modifications and additions within the scope of the present invention are included in the present invention. It is.

  For example, in the embodiment, the first diaphragm 45, the second diaphragm 47, and the third diaphragm 52 may be fixed diaphragms. By using a fixed throttle, the pressure can be set to a desired value. Further, as the fixed throttle, a throttling device or a through-hole or inflow hole itself having a small diameter may be used.

Further, the pressure adjustment unit for adjusting the pressure P ₄₉ in the back pressure chamber 49, as long as have been described third aperture 52 as an example, which drained the pressure fluid 60 in the back pressure chamber 49 to the outside to adjust the pressure For example, a relief valve that allows the pressure fluid 60 to flow out to the outside at a predetermined pressure or more may be used other than the throttle. If the second throttle 47 and the third throttle 52 are relief valves, the back pressure chamber 49 can generate a pressure that presses the stationary seal ring 20 against the rotary seal ring 10 in a sealed state when the device is not used. The spring 21 is not always necessary.

  Moreover, although the example which provides the 3rd aperture_diaphragm | restriction 52 in the housing main body 31 was demonstrated, you may provide in the stationary side sealing ring 20 or the case 32. FIG.

  Further, the example in which the pressure fluid 60 supplied from the pressure fluid supply device 2 is branched by the branch chamber 43 and supplied to the back pressure chamber 49 has been described. You may provide the pressure fluid supply apparatus which supplies a pressure fluid directly to a chamber separately.

1 Rotating shaft 2 Pressure fluid supply device (Pressure fluid supply source)
5 Recovery Container 10 Rotating Side Seal Ring 20 Stationary Side Seal Ring 30 Housing 31 Housing Body 32 Case 33 Bush 40 Pressure Fluid Path 43 Branch Chamber 45 First Restriction 46 Through Hole 47 Second Restriction 48 Inflow Hole 48 ′ Inflow Hole 49 Back Pressure Chamber 51 Discharge-side flow path 52 Third restriction (pressure adjusting part)
53 Through hole (external)
54 Through-hole 55 Discharge chamber 60 Pressure fluid 62 Supply path 64 Branch path 66 Discharge path 100 Static pressure type mechanical seal device A Atmospheric side M Machine inside F1 Separation force F2 Approach force P ₄₃ Branch chamber pressure P ₄₉ Back pressure chamber pressure

Claims (4)

A hydrostatic mechanical seal device that seals between a housing and a rotating shaft and introduces and ejects a pressure fluid between sliding surfaces.
A rotating side sealing ring that rotates together with the rotating shaft;
A stationary side sealing ring provided opposite to the rotation side sealing ring and having a supply path for supplying the pressure fluid between the sliding surfaces;
A back pressure chamber formed on the opposite side of the sliding surface of the stationary side sealing ring by the housing and the stationary side sealing ring, and pressure fluid is supplied from an inflow hole;
A pressure adjusting unit that adjusts the pressure of the back pressure chamber by causing the pressure fluid in the back pressure chamber to flow out to the outside, a fluid that leaks from between the sliding surfaces, and a pressure fluid that flows out of the pressure adjusting unit; A hydrostatic mechanical seal device characterized by comprising a discharge path for joining and discharging .   The hydrostatic mechanical seal device according to claim 1, wherein a throttle is provided in the inflow hole.   The hydrostatic mechanical seal device according to claim 1, further comprising a branch chamber that branches the pressure fluid into the supply path and the inflow hole.   The hydrostatic mechanical seal device according to any one of claims 1 to 3, wherein the pressure adjusting unit is a pressure regulator that is detachably provided on the housing or the stationary side sealing ring.

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