JPH051776A - Shaft seal packing sealing device - Google Patents

Abstract

PURPOSE:To enhance the original function of a shaft seal packing, improve sealing performance and automatically keep the proper face pressure of the packing if subjected to stress relaxation by correcting the non-uniform face pressure of the packing and giving proper face pressure to the packing over a vertically wide range. CONSTITUTION:A space section 8 is provided between an upper packing 3a and a lower packing 3b where a pair of pistons 10a, 10b are stored which have inner and outer peripheries put in close contact with each other or sealed by the arrangement of an 0-ring 11, etc. A packing box 1 has the periphery provided with a pressure medium filling port 12 communicating with the space section to connect thereto a pressure medium supply device 30 which supplies a pressure medium at a preset pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft seal packing sealing device.

[0002]

2. Description of the Related Art Conventionally, a shaft sealing packing sealing device as shown in FIG. 3 has been proposed in a staffing box for handling ignitable gases such as LNG, radioactive fluids in nuclear power plants, and other harmful gases.

In this conventional apparatus, an upper packing 3a and a lower packing 3b are housed between a packing box 1 and a shaft 2 which is loosely inserted in the packing box 1, and both packings 3a and 3b are accommodated.
Is to be tightened with a packing retaining ring 4 which is pushed in from the upper opening of the packing box 1 with a packing retaining bolt 5.

A lantern ring 6 is housed between the upper packing 3a and the lower packing 3b.
A discharge port 7 communicating with a space 8 formed by the lantern ring 6 is provided on the peripheral surface of the packing box 1.

That is, in the above-mentioned conventional device, the packing has a high flexibility, and the applied tightening surface pressure acts as a lateral surface pressure to perform shaft sealing. However, the packing itself has a characteristic that it is better than the tightening portion. Leakage from the lower packing 3b with insufficient tightening surface pressure in view of the fact that the tightening surface pressure decreases with distance and the original function cannot be fully exerted, and stress relaxation of the packing synergizes to cause external leakage. From the outlet 7 to a safe part (usually
Drain tank etc.).

[0006]

However, the above-mentioned conventional device abandons a part of the shaft sealing function of the lower packing 3b and is not efficient at all, and the clamping surface of the packing of the conventional device is not effective. The pressure is indicated by a broken line in FIG. 4 (the vertical axis represents the vertical position of the packing, and the horizontal axis represents the magnitude of the packing surface pressure. L1 and L2 in the figure represent the length of the lantern ring. Since there is a large difference between the upper part and the lower part, and the range in which the proper surface pressure is maintained is very small, the reliability of the sealing performance cannot be maintained.

Further, even with the above-mentioned conventional apparatus, the stress relaxation of the packing caused by continuous use has to be dealt with by tightening management of the packing, and there is a drawback that the management at the use site is complicated. I can't avoid it.

That is, the problem of the conventional device is that the surface pressure of the shaft-sealing packing becomes uneven between the upper part and the lower part, and the function of the packing itself cannot be sufficiently exerted.
The proper surface pressure cannot be maintained for a long time due to stress relaxation of the packing.

Therefore, the present invention has been made in view of the above-mentioned drawbacks. By correcting the non-uniformity of the surface pressure of the shaft-sealing packing, and by giving an appropriate surface pressure over a wide range in the vertical direction of the packing, the original function of the packing is improved. Improves hermeticity, and
An object of the present invention is to provide a shaft seal packing sealing device which can easily maintain a proper surface pressure even if stress relaxation occurs in the packing.

[0010]

In order to solve the above-mentioned problems, the structure of the present invention, which is based on the above-mentioned claims, has a packing box 1 and a shaft loosely inserted into the packing box 1 in order to solve the above-mentioned problems. Between the upper packing 3a and the lower packing 3
In the shaft-sealing packing sealing device in which the packings 3b and 3b are housed, and the packings 3a and 3b are tightened by the packing presser ring 4 which is pressed by the packing presser bolt 5 from the upper opening of the packing box 1. A space 8 is provided between the packing 3b and a pair of pistons 10a and 10b whose inner and outer peripheral surfaces are intimately contacted with each other or an O-ring 11 or the like is hermetically housed therein. The pressure medium injection port 1 communicating with the space 8 is provided on the peripheral surface.
2 is provided, and a pressure medium feeding device 30 that feeds the pressure medium at a predetermined pressure is connected to the pressure medium inlet 12, and a technical means is provided.

[0011]

Therefore, in the shaft seal packing sealing device of the present invention, the set load is applied by the packing holding bolt 5 as in the conventional case, but at the same time, the pressure medium such as grease is supplied from the pressure medium inlet 12 at a predetermined pressure. Press in. Then, the pistons 10a and 10b receive a force in a direction to separate in the vertical direction by the pressure medium, and the upper packing 3a receives a load from the packing pressing bolt 5 through the packing pressing ring 4 from above and an upper piston 10a from below. The lower packing receives the load due to the pushing force of the lower piston 10b, and as a result, the tightening surface pressure between the upper packing 3a and the lower packing 3b becomes "Fig. As shown by the solid line in "4", it has the effect of correcting the unevenness in the upper and lower parts.

When stress relaxation of the packing progresses due to long-term use, both pistons 10a and 10b undergo stress relaxation if the pressure force of the pressure medium injected from the pressure medium inlet 12 maintains a predetermined pressure. It moves in the direction of separating in response to the above, and exhibits the action of automatically maintaining the tightening surface pressure.

[0013]

Embodiments of the present invention will now be described with reference to the accompanying drawings.

In the figure, 1 is a packing box, and an upper packing 3a and a lower packing 3b are housed between the packing box 1 and a shaft 2 loosely inserted in the packing box 1, and both packings 3a, 3b are housed. As in the conventional case, the packing holding ring 4 is pushed in by the packing holding bolt 5 from the upper opening of the packing box 1 and is tightened.

In the illustrated example, the packing holding ring 4 is provided with a flange 4a as a separate member, but the flange 4a may be formed integrally with the packing holding ring 4, and the packing holding bolt 5 is a base end. Is rotatably supported on the packing box 1, and the upper part of the packing box 1 protrudes upward from the through hole 13 formed in the flange 4a
A nut 5a is screwed into this protruding portion, and the nut 5a
The packing holding ring 4 is pushed into the packing box 1 through the flange 4a by tightening the. The packing holding bolt 5 has a screw foot of a screw head having a screw head at the upper portion of the flange 4a. It goes without saying that the through hole 13 may be penetrated from above and screwed into a flange portion or the like of the packing box 1 not shown.

The present invention also provides the above-mentioned upper packing 3a.
A space portion 8 is provided between the lower packing 3b and the lower packing 3b, and a pair of pistons 10a and 10b whose inner and outer peripheral surfaces are intimately contacted with each other or an O-ring 11 or the like is sealed are housed therein.

It is necessary that the packings 10a and 10b have a space 8 between them even when they are close to each other. In this embodiment, the lower piston 10b is provided.
A ring 14 for securing a space, the outer diameter of which is smaller than the outer diameter of the piston 10b and the inner diameter of which is larger than the inner diameter of the piston 10b, is provided so as to project on the upper surface of the ring 14, and a pressure medium is provided inside the ring 14 on the peripheral surface thereof. Through holes 15,15,15
Opened.

In the illustrated example, both packings 10 are
Both a and 10b are provided with O-rings 11 and 11 respectively on the inner and outer peripheral surfaces to maintain the hermeticity. However, the O-ring 11 is not essential, and the inner and outer peripheral surfaces of both packings 10a and 10b are simply packed. The inner peripheral surface of the box 1 and the outer peripheral surface of the shaft 2 may be in close contact with each other. In this case, a slight leakage of the pressure medium from the contact surface is unavoidable, but as the pressure medium, grease (particularly inert grease) or the like may be used. When the use of a lubricant that can be used is permitted, the lubricant may be positively used for lubrication of the sliding surfaces of the pistons 10a and 10b and the leakage of fibers of the packings 3a and 3b.

A pressure medium injection port 12 communicating with the interior of the space 8 is provided on the peripheral surface of the packing box 1, and a pressure medium is supplied to the pressure medium injection port 12 at a predetermined pressure. The device 30 is connected.

Grease is usually used as the pressure medium, but water, gas or the like may be used depending on the specifications.

The pressure medium feeding device 30 may be any device capable of pressure-feeding the pressure medium at a predetermined pressure, and a plurality of pressure medium inlets 12 are provided from a pressure medium container kept at a predetermined pressure.
Although it may be configured to be electrically connected by a connecting pipe, in the illustrated example, one simple pressure medium feeding device 30 is connected to each pressure medium inlet 12.

As shown most clearly in FIG. 2, the pressure medium feeding device 30 is in the form of a cylinder having a pressure medium inlet 33 having a check valve 32 in a base 31 and a pressure medium discharge port 34. Of the pressure medium reservoir 35, and a piston 36 is inserted into the pressure medium reservoir 35 through an upper opening thereof so that the piston 36 can be moved in and out, and an injection amount scale 37 for indicating an ascending / descending position of the piston 36 is provided on the base 31. A spring case 39 having a window 38 provided with (not shown in the figure, graduated at predetermined intervals in the up and down direction on the edge of the window 38, etc.) is connected,
In the spring case 39, the spring 40 located above the piston 36 and the spring pusher 4 located above this spring 40.
1, a spring pressing screw 43 for pressing the spring pressing body 41 is provided on the lid 45 of the spring case 39, and a spring deflection display scale for displaying the screwing amount of the spring pressing screw 43 on the lid 45. A plate 44 is provided upright.

That is, the pressure medium feeding device 30 is
The pressure medium in the pressure medium reservoir 35 or the space 8 is pressurized by the load obtained by the set load of the spring 40.
The pressurization of the pressure medium is continued within the permissible range of the set load of the spring 40, but if the pressure medium leaks from the pressure medium reservoir 35, the applied pressure falls below the permissible range. At this time, if the amount of bending of the spring 40 can be displayed, it can be confirmed that the pressure medium is within the allowable pressing force range. If the compressibility of the pressure medium is ignored, the amount of up and down movement of the piston 36 and the amount of up and down movement of the spring pressing body 41 can be confirmed. (Same as the tightening amount of the spring cap screw 43)
The amount of deflection can be displayed by the difference between and, and the difference can be displayed by the injection amount scale 37 and the spring deflection display scale plate 44. Specifically, when the injection amount scale 37 and the scale of the spring flexure display scale plate 44 are set to have the same intervals, the maximum flexure occurs in the spring 40 when the same position on both scales is pointed to, and the pressing force is increased. Is set to the maximum allowable value. When the pressure medium flows out to the outside in this state, the value indicating the injection amount scale 37 decreases, so that the allowable decrease value (a state where the allowable minimum value is obtained) is 1 to 3.
If the scale is set, it can be confirmed that the predetermined pressure is maintained in this range.

If the injection amount scale 37 and the scale of the spring flexure display scale plate 44 are compared with each other and the predetermined scale range is about to be exceeded, the spring holding screw 43 is used. The set pressure is restored by tightening according to the indicated value.

In FIG. 1, 16 is an air vent plug.

[0026]

As described above, the shaft seal packing sealing device of the present invention has a greatly improved tightening surface pressure between the upper packing 3a and the lower packing 3b as compared with the conventional device, and the difference between the upper and lower parts. Since a proper tightening surface pressure can be secured over a wide range while the pressure medium feeding device 30 is operating, a highly reliable shaft seal packing seal device having a sufficient packing function can be exhibited. What can be provided.

Further, according to the present invention, even if the stress relaxation of the packing progresses, an appropriate tightening surface pressure can be automatically secured while the pressure medium feeding device 30 is operating, and the shaft seal is easy to maintain. A packing sealing device can be provided.

If the packings 3a, 3b are made of all-graphite material, the life is said to be semi-permanent unless they are damaged. If an inert grease is used as the pressure medium, the deterioration life is long and the O-ring 11 Use this O-ring 11
Since it is lubricated with grease, there is almost no leakage of the pressure medium, and there is no need for maintenance at the site of use, so that it is possible to provide a shaft seal packing sealing device.

Although not mentioned above, it is said that a skill is required for manufacturing this type of shaft seal packing sealing device and for assembling it when replacing the packing. That is,
The size of the packing is smaller than the size of the inner / outer sealed portion in order to insert the packing into the packing box 1. Therefore, even if the packing is simply inserted into the packing box 11, there is a gap in the sealed portion. Therefore, every time one or two packings are inserted, the packing is tamped with a cylindrical jig. You have to do some work to make the packing stick,
This work requires a special jig, and the packing has a restoring force, so proper packing of the packing cannot be done without skill. On the other hand, in the case of the present invention, if all the packings are inserted and the pressure medium for assembling (air or nitrogen gas etc.) is pressure-fed from the pressure medium inlet 12, the packings instantly receive the compression surface pressure and are sufficiently airtight. If the tightening surface pressure is obtained and the necessary pressure is applied by the packing holding bolt 5 immediately after the pressure is removed, the surface pressure can be maintained even in the lower packing, which not only improves the sealing performance of the packing but also improves the healing. It does not require tools or skill and has the advantage of stable quality.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a pressure medium feeding device used in the present invention.

FIG. 3 is a sectional view of a conventional example.

FIG. 3 is a distribution diagram of packing tightening surface pressure between the device of the present invention and the conventional device.

[Explanation of symbols]

 1 packing box 2 shaft 3a upper packing 3b lower packing 4 packing retaining ring 5 packing retaining bolt 8 space 10a piston 10b piston 11 O-ring 12 pressure medium inlet 30 pressure medium feeding device

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[Procedure amendment]

[Submission date] May 29, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a pressure medium feeding device used in the present invention.

FIG. 3 is a sectional view of a conventional example.

FIG. 4 is a distribution diagram of packing tightening surface pressures of the device of the present invention and the conventional device.

Claims (1)

Claims: 1. An upper packing and a lower packing are housed between a packing box and a shaft loosely inserted in the packing box, and both packings are fitted with packing holding bolts from an upper opening of the packing box. In a shaft-sealing packing sealing device configured to be tightened by a packing retaining ring to be pushed in, a space is provided between the upper packing and the lower packing, and inner and outer peripheral surfaces are closely contacted or an O-ring or the like is arranged in the space. The pair of sealed pistons are stored in the packing box.
A shaft seal packing sealing device, comprising: a pressure medium injection port communicating with the inside of a space; and a pressure medium supply device for supplying a pressure medium at a predetermined pressure to the pressure medium injection port.