JP4018349B2 - Shaft seal device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a shaft seal device for preventing leakage at a through shaft portion of a fluid device such as a stirring device.
[0002]
[Prior art]
Conventionally, a shaft seal device as shown in FIG. 5 is generally used in order to prevent leakage at a through shaft portion of a fluid device such as a stirring device, a mixing device, and a reaction device. As shown in FIG. 5, the shaft seal device 41 includes a gland packing 43 in a packing box 42 and presses the gland packing 43 with a packing presser 44. The packing retainer 44 is fastened by a fastening bolt 45 provided in the packing box 42 and a fastening nut 46 attached to the fastening bolt 45.
[0003]
[Problems to be solved by the invention]
However, in the conventional shaft seal device, as shown in FIG. 6, a clearance S is provided between the inner periphery of the bottom portion 42a of the packing box 42 and the shaft 47 so as not to contact each other. The components of the fluid inside the device are deposited on S (FIG. 6, mesh portion). For this reason, when operating a fluid apparatus using a different kind of fluid later, there was a problem that a deposit mixed in with a different kind of fluid. In particular, when the fluid is food, medicine or the like, it is necessary to avoid mixing old deposits into the fluid even if the fluid is the same type. This fluid accumulation is likely to occur in the case of a highly viscous fluid such as food.
The present invention has been proposed in view of the above circumstances, and is a shaft seal that can prevent the accumulation of fluid components inside the device in the clearance between the inner periphery of the bottom of the packing box and the shaft. An object is to provide an apparatus.
[0004]
[Means for Solving the Problems]
The present invention employs the following means in order to achieve the above object. That is, in a shaft sealing device including a packing box having at least one gland packing, the end surfaces of the pair of annular members are in contact with each other in the axial direction, positioned closer to the liquid sealing side than the gland packing in the packing box. And a groove for blowing gas to the gland packing sliding surface from the outer peripheral side to the inner peripheral side when viewed in the axial direction is connected to at least one of the contact surfaces on the outer peripheral side and the inner peripheral side A ring-shaped bush that is formed to have a reduced diameter, a gas filling port that passes through the packing box and introduces gas into the groove of the bush, and a gas supply that supplies the gas to the gas filling port Means is provided (claim 1).
With this configuration, the gas supplied from the gas supply means to the gas filling port is introduced into the groove of the bush, flows from the outer peripheral side of the groove to the inner peripheral side, and is blown onto the packing sliding surface. With this gas, the fluid inside the device that has entered the clearance between the inner periphery of the bottom of the packing box and the shaft can be blown out toward the inside of the device. As a result, accumulation of fluid components can be prevented, and further, fluid can be prevented from entering the packing sliding surface. In addition, the gas can cool the vicinity of the packing sliding surface whose temperature rises due to heat generated between the gland packing and the shaft. Further, the bush is configured by abutting the end faces of the pair of annular members in the axial direction, and a groove is formed on at least one of the abutting surfaces. Therefore, the groove can be easily formed.
[0005]
In addition, the gas introduced into the spirally formed groove whose diameter is reduced from the outer peripheral side to the inner peripheral side when viewed from the axial direction is given inertia in the circumferential direction of the shaft by passing through the groove. Will be supplied over the entire circumference. As a result, the internal fluid that has entered the clearance between the inner periphery of the bottom of the packing box and the shaft can be effectively blown away.
The groove of the bush, it is preferable that groove cross-sectional area decreases toward the inner peripheral side from the outer side (claim 2). In this case, the gas introduced into the groove flows while increasing the flow velocity from the outer peripheral side to the inner peripheral side, and is supplied to the packing sliding surface. Therefore, the clearance between the inner periphery of the bottom of the packing box and the shaft is reduced. The invading internal fluid can be blown off more effectively.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
(Embodiment 1)
FIG. 1 is a schematic cross-sectional view showing an embodiment of a shaft seal device according to the present invention. Hereinafter, the configuration of the shaft seal device will be described with reference to the drawings.
As shown in FIG. 1, the shaft seal device 1 mainly includes a flange 2 fixed to the apparatus body, a packing box 3 in which a gland packing 7 and the like are installed, a packing presser 4 for fixing the gland packing 7 and the like, A sliding ring 5, gas supply means 16 for supplying gas, and the like are provided.
The packing box 3 includes a plurality of gland packings 7, a bushing 8 on the sealing liquid side of the gland packing 7 d on the outermost liquid side of the gland packings 7, a lantern ring 9 between the gland packings 7 b and 7 c, and a maximum Spacer rings 15 are respectively provided on the atmosphere side of the air side gland packing 7a. In addition, a gas filling port 12 for introducing gas into the bush 8 is formed through the packing box 3.
[0007]
The gland packing 7, the bush 8, the lantern ring 9 and the spacer ring 15 are elastically pressed by the pressing mechanism 11 through the packing presser 4 with a predetermined pressure. With this pressure, the gland packing 7 is deformed so as to be crushed in the longitudinal direction of the shaft 10, and a pressing force is generated between the gland packing 7 and the shaft 10. The pressing mechanism 11 includes a tightening bolt 11a through which a packing retainer 4 screwed into the packing box 3 is inserted, and a compression coil spring 11b, a spring collar 11c, and a tightening nut 11d attached to the tightening bolt 11a. The packing presser 4 is urged leftward in the drawing by the urging force of the compression coil spring 11b.
[0008]
The packing box 3 is pressed against the flange 2 by the pressing mechanism 13 via the sliding ring 5 with a predetermined pressure, and O-rings 6 are provided on both end faces of the sliding ring 5. Similar to the pressing mechanism 11, the pressing mechanism 13 includes a tightening bolt 13a screwed into the flange 2, and a compression coil spring 13b, a spring collar 13c, and a tightening nut 13d attached to the tightening bolt 13a.
[0009]
The sliding ring 5 has a flange 2 side end surface formed in a spherical convex shape having a center Q on the axis of the shaft 10 and a packing box 3 side end surface formed in a planar shape. Further, the end surface of the flange 2 that is in contact with the spherical convex end surface of the sliding ring 5 is formed in a spherical concave shape corresponding to the spherical convex shape. The spherical convex end surface of the sliding ring 5 and the spherical concave end surface of the flange 2 are slidable in all directions along the spherical surface (L direction in the sectional view shown in FIG. 1). On the other hand, the end surface of the packing box 3 that is in contact with the planar end surface of the sliding ring 5 is formed in a planar shape. The planar end surface of the packing box 3 can slide in the radial direction of the shaft (M direction in FIG. 1) with respect to the planar end surface of the sliding ring 5.
Thus, the shaft runout in the inclination direction and the radial direction of the shaft is caused by sliding between the sliding ring 5, the flange 2 and the packing box 3, and the longitudinal direction of the shaft (the N direction in FIG. 1). ) Can be followed by the packing box 3 by the pressing mechanism 13 respectively. As a result, the packing box 3 can follow the three-dimensional displacement of the shaft runout, and leakage of the internal fluid can be prevented.
[0010]
The annular bush 8 housed in the packing box 3 is composed of a packing side member 8a and a sealing liquid side member 8b which form a pair as shown in FIG. As shown in FIGS. 2 (a) and 2 (b), the packing side member 8a has a flat end on the packing side and a tapered end surface on the sealing member 8b side. A spiral groove 14 communicating with the outer peripheral side and the inner peripheral side for supplying gas to the sliding surface (inner peripheral surface) has a spiral shape whose diameter decreases from the outer peripheral side to the inner peripheral side when viewed in the axial direction. Is formed. The groove 14 is formed so that the groove cross-sectional area decreases from the outer peripheral side toward the inner peripheral side, and the outer peripheral end communicates with the gas filling port 12. The cross-sectional shape of the groove 14 is not limited to an arc shape as shown in FIG. 2A, and may be a concave shape, for example. On the other hand, as shown in FIG. 2A, the sealing-side member 8b has a flat end surface on the sealing side and an end surface on the packing-side member 8a side that comes into contact with the tapered end surface of the packing-side member 8a. It is formed in a taper shape.
[0011]
The gas supplied to the gas filling port 12 by the gas supply means 16 is introduced into the groove 14 from the outer peripheral end of the groove 14 of the bush 8. The gas introduced into the groove 14 flows while increasing the flow velocity from the outer peripheral side to the inner peripheral side of the groove 14 and is blown to the vicinity of the packing sliding surface, and the inner periphery of the bottom portion 3a of the packing box 3 and the shaft 10 The internal fluid that has entered the clearance S is blown off toward the inside of the device. Here, since gas is given inertia in the circumferential direction of the shaft by passing through the spiral groove 14, it is supplied over the entire circumference of the shaft. As a result, it is possible to prevent components of the internal fluid from accumulating in the clearance S between the inner periphery of the bottom 3a of the packing box 3 and the shaft 10, and to prevent the internal fluid from entering the packing sliding surface. Can be prevented.
[0012]
(Embodiment 2)
FIG. 3 is a schematic cross-sectional view showing another embodiment of the shaft seal device according to the present invention, and the configuration of this shaft seal device will be described below based on the drawings.
As shown in FIG. 3, the shaft seal device 21 mainly includes a primary seal portion A on the sealing liquid side, a secondary seal portion B on the atmosphere side, and a space between the primary seal portion A and the secondary seal portion B. A sliding ring 28, gas supply means 40 for supplying gas, and the like are provided.
The primary seal portion A includes a packing box 22 in which the gland packing 23 and the like are installed, a packing presser 25 and the like for fixing the gland packing 23 and the like. In the packing box 22, a plurality of gland packings 23 and bushes 24 are respectively provided on the sealing side of the gland packing 23c on the outermost liquid side among these gland packings 23. The packing box 22 has a gas filling port 27 for introducing gas into the bush 24, and the packing retainer 25 is filled with a purge gas such as nitrogen between the primary seal portion A and the secondary seal portion B. Each gas filling port 29 is formed through.
[0013]
The gland packing 23 and the bush 24 are elastically pressed with a predetermined pressure by a pressing mechanism 26 via a packing presser 25. With this pressure, the primary seal portion A is deformed so as to crush the gland packing 23 in the longitudinal direction of the shaft 39, and a pressing force is generated between the gland packing 23 and the shaft 39. The pressing mechanism 26 includes a tightening bolt 26a through which a packing retainer 25 screwed into the packing box 22 is inserted, and a compression coil spring 26b, a spring collar 26c, and a tightening nut 26d attached to the tightening bolt 26a. The packing presser 25 is urged leftward in the drawing by the urging force of the compression coil spring 26b.
[0014]
The secondary seal portion B includes a packing box 30 in which the gland packing 31 and the like are internally installed, a packing presser 34 and the like for fixing the gland packing 31 and the like. The packing box 30 includes a plurality of gland packings 31, a spacer ring 32, a gland packing 31 b on the sealing side of the gland packing 31 d on the most sealed side of the gland packing 31 and the atmosphere side of the gland packing 31 a on the maximum side. , 31c are respectively provided with lantern rings 33. Further, the packing box 30 is provided with a gas leak port 38 for removing the purge gas sealed between the primary seal portion A and the secondary seal portion B.
[0015]
The gland packing 31, the spacer ring 32 and the lantern ring 33 are pressed with a predetermined pressure by a pressing mechanism 35 via a packing presser 34. By this pressure, in the secondary seal portion B, the gland packing 31 is deformed so as to be crushed in the longitudinal direction of the shaft 39, and the fluid is sealed by reducing the gap between the gland packing 31 and the shaft 39. . As with the pressing mechanism 26, the pressing mechanism 35 includes a tightening bolt 35a through which a packing presser 34 screwed into the packing box 30 is inserted, and a compression coil spring 35b, a spring collar 35c, and a tightening nut 35d mounted on the tightening bolt 35a. The packing presser 34 is urged to the left in the drawing by the urging force of the compression coil spring 35b.
[0016]
The packing box 30 of the secondary seal portion B is pressed by the pressing mechanism 36 to the packing presser 25 of the primary seal portion A through the sliding ring 28 with a predetermined pressure. , An O-ring 37 is provided. The pressing mechanism 36 includes a tightening bolt 36a screwed into the packing retainer 25, a compression coil spring 36b and a tightening nut 36c attached to the tightening bolt 36a.
[0017]
The sliding ring 28 is formed in a spherical convex shape with the end surface on the primary seal portion A side having a center Q on the axis of the shaft 39, and the end surface on the secondary seal portion B side in a planar shape. Further, the end surface of the packing presser 25 of the primary seal portion A that is in contact with the spherical convex end surface of the sliding ring 28 is formed in a spherical concave shape corresponding to the spherical convex shape. The spherical convex end surface of the sliding ring 28 and the spherical concave end surface of the packing retainer 25 can slide in all directions along the spherical surface (L direction in the sectional view shown in FIG. 3). . On the other hand, the end surface of the packing box 30 of the secondary seal portion B that is in contact with the planar end surface of the sliding ring 28 is formed in a planar shape. The planar end surface of the packing box 30 can slide in the radial direction of the shaft (the M direction in FIG. 3) with respect to the planar end surface of the sliding ring 28.
Thus, the shaft runout in the inclination direction and the radial direction of the shaft is caused by sliding between the sliding ring 28, the packing presser 25 and the packing box 30, and in the longitudinal direction of the shaft (N in FIG. 3). The packing box 30 can follow the axial deflection in the direction) by the pressing mechanism 36. As a result, the packing box 30 can follow the three-dimensional displacement of the shaft runout, and leakage of the internal fluid can be prevented.
[0018]
A purge gas is supplied between the primary seal portion A and the secondary seal portion B from the gas filling port 29 so that the internal fluid does not enter the packing sliding surface of the primary seal portion A. Further, the purge gas and the gas leaked from the inside of the apparatus are collected from the gas leak port 38 via the lantern ring 33 so as not to leak to the atmosphere side. The purge pressure of the purge gas is preferably higher by about 0.05 to 0.1 MPa than the equipment internal pressure. For example, when the purge pressure is only 0.05 MPa or less higher than the internal pressure of the device, the effect of preventing the intrusion of the internal fluid by sealing the purge gas is reduced. On the other hand, when the purge pressure is 0.1 MPa or more higher than the internal pressure of the equipment, excessive pressure acts on the packing in addition to the packing tightening pressure, so the surface pressure between the packing inner periphery and shaft outer periphery increases. This causes abnormal sliding and leakage of internal fluid, and purge gas leaks from between the sliding ring 28 and the primary seal portion A and secondary seal portion B.
[0019]
The annular bush 24 housed in the packing box 22 of the primary seal portion A is constituted by a packing side member 24a and a sealing side member 24b which form a pair as shown in FIG. 4 (a). A plurality of grooves 241 for supplying gas to the packing sliding surface are arranged on the end surface of the packing side member 24a on the sealing liquid side member 24b side as shown in FIGS. 4 (a) and 4 (c). Is formed. As shown in FIG. 4B, the groove 241 has a bottom surface that is tapered and communicates with the outer peripheral side and the inner peripheral side. Further, the groove 241 is formed so that the groove cross-sectional area decreases from the outer peripheral side toward the inner peripheral side. A groove 242 that communicates with the groove 241 is formed on the circumferential surface of the packing-side member 24 a and communicates with the gas filling port 27. On the other hand, the sealing liquid side member 24b is formed in an annular shape having flat end faces.
[0020]
The gas supplied to the gas filling port 27 by the gas supply means 40 is introduced into the groove 242 of the bush 24. Then, the gas introduced into the groove 242 flows through the groove 242 from the outer peripheral side to the inner peripheral side of the groove 241 while increasing the flow velocity, and is blown to the vicinity of the packing sliding surface. The internal fluid that has entered the clearance S between the inner periphery and the shaft 39 is blown out toward the inside of the device. As a result, it is possible to prevent the component of the internal fluid from accumulating in the clearance S between the inner periphery of the bottom 22a of the packing box 22 and the shaft 39, and to prevent the internal fluid from entering the packing sliding surface. Can be prevented.
[0021]
In the first embodiment, the sliding ring 5 has the flange 2 side end surface formed into a spherical convex shape and the packing box 3 side end surface formed into a planar shape. However, the present invention is not limited to this. The 3 side end face may be formed in a spherical convex shape, and the flange 2 side end face may be formed in a planar shape. Further, the sliding ring 5 side is formed into a spherical convex shape, and the flange 2 side is formed into a spherical concave shape. However, the present invention is not limited to this, and the sliding ring 5 side is formed into a spherical concave shape and the flange 2 side is formed. You may form in a spherical convex shape. The sliding ring 5 is preferably made of a material having a low coefficient of friction, such as a fluororesin material, so that the sliding ring 5 can easily slide against shaft runout. With respect to these points, the same applies to the sliding ring 28 and the like in the second embodiment.
[0022]
Further, in the first embodiment, the bush 8 has the configuration in which the spiral groove 14 is formed as described above. However, the configuration is not limited to this, and the configuration like the bush 24 in the second embodiment is the same. It is also possible to do. Similarly, the configuration of the bush 24 in the second embodiment may be the same as the configuration of the bush 8 in the first embodiment. The flow rate of the gas supplied from the bush 8 or the bush 24 to the packing sliding surface is preferably 5 m / s or more in order to blow off the internal fluid that has entered the clearance S into the device.
[0023]
Furthermore, the groove 14 in the first embodiment and the groove 241 in the second embodiment are preferably formed so that the groove cross-sectional area decreases from the outer peripheral side toward the inner peripheral side as described above. However, it is not limited to this.
In each of the above embodiments, the packing box includes a plurality of gland packings. However, the present invention is not limited to this, and it is sufficient that at least one gland packing is provided.
[0024]
【The invention's effect】
As described above, in the shaft seal device according to the present invention, the gas supplied from the gas supply means to the gas filling port is introduced into the groove of the bush and flows from the outer peripheral side to the inner peripheral side of the groove, and the packing slide Since it is sprayed on the moving surface, the fluid inside the device that has entered the clearance between the inner periphery of the bottom of the packing box and the shaft can be blown out toward the inside of the device by the gas. As a result, accumulation of fluid components can be prevented, and further, fluid can be prevented from entering the packing sliding surface. In addition, the gas can cool the vicinity of the packing sliding surface whose temperature rises due to heat generated between the gland packing and the shaft. Further, the bush is configured by abutting the end surfaces of the pair of annular members in the axial direction, and a groove is formed on at least one of the contact surfaces, so that the groove can be easily formed.
[0025]
Further, since the groove of the bush is formed in a spiral shape whose diameter is reduced from the outer peripheral side to the inner peripheral side when viewed from the axial direction , the gas introduced into the groove passes through the groove and moves in the circumferential direction of the shaft. Since inertia is imparted, it is supplied over the entire circumference of the shaft. As a result, the internal fluid that has entered the clearance between the inner periphery of the bottom of the packing box and the shaft can be effectively blown away.
In addition, when the groove cross section of the bush groove decreases from the outer peripheral side toward the inner peripheral side, the gas introduced into the groove flows while increasing the flow velocity from the outer peripheral side to the inner peripheral side, and packing is performed. Supplied to the sliding surface. Thereby, the internal fluid that has entered the clearance between the inner periphery of the packing box and the shaft can be blown off more effectively.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a shaft seal device according to the present invention.
FIG. 2 is a view showing a bush used in an embodiment of a shaft seal device according to the present invention, in which (a) is a cross-sectional view thereof and (b) is a front view thereof.
FIG. 3 is a schematic cross-sectional view showing another embodiment of the shaft seal device according to the present invention.
FIG. 4 is a view showing a bush used in another embodiment of the shaft seal device according to the present invention, (a) is a side view thereof, (b) is a sectional view thereof, and (c) is a front view thereof. is there.
FIG. 5 is a schematic sectional view showing a conventional shaft seal device.
FIG. 6 is an enlarged view of a main part showing a state in which fluid is accumulated in the clearance in a conventional shaft seal device.
[Explanation of symbols]
A Primary seal portion B Secondary seal portion 1 Shaft seal device 2 Flange 3, 22, 30 Packing box 4, 25, 34 Packing retainer 5, 28 Sliding ring 7, 23, 31 Gland packing 8, 24 Bush 12, 27 29 Gas filling port 14, 241, 242 Groove 16, 40 Gas supply means

Claims (2)

In a shaft seal device provided with a packing box having at least one gland packing,
Positioned on the liquid sealing side from the gland packing in the packing box, the end surfaces of the pair of annular members are configured to contact each other in the axial direction, and at least one of the contact surfaces includes an outer peripheral side and an inner peripheral side. A groove for blowing gas to the gland packing sliding surface, and an annular bush formed in a spiral shape whose diameter is reduced from the outer peripheral side to the inner peripheral side when viewed from the axial direction ;
A gas filling port for introducing gas into the groove of the bush through the packing box;
A shaft seal device comprising gas supply means for supplying the gas to the gas sealing port. The shaft seal device according to claim 1, wherein the groove has a groove cross-sectional area that decreases from the outer peripheral side toward the inner peripheral side .

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