JPH0461986B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a gland packing box constituting a shaft sealing part of a liquid device, and in particular, to a gland packing box in which sealing fluid pressure is applied unevenly to the gland packing. The present invention relates to a structure of a gland packing box that can improve sealing performance, reduce power loss, and prolong the life of the gland packing by improving the various disadvantages caused by this.

[Prior Art] As a general packing box structure for sealing the rotating shaft of a fluid device, the structure shown in FIG. 11 is known. In the figure, a plurality of gland packings B are inserted into the packing box A, and by pressing the gland packing B in the axial direction with a predetermined tightening pressure using the packing holder C, the outer periphery of the rotating shaft D and the gland packing A gap (not shown) between the inner circumference of B and the inner circumference of B to allow a slight leakage of the sealing fluid.
configured to form and seal.

[Problems to be Solved by the Invention] However, in the structure of the conventional packing box, the sealing fluid pressure is unevenly applied only to the inner periphery of the gland packing B, as shown by the arrow in FIG. In other words, a pressure imbalance occurs in which the sealing fluid pressure is biased only in one direction in the radial direction.

In such an unbalanced state, the inner periphery of the gland packing B is likely to undergo abnormal deformation in which the diameter expands due to the sealing fluid pressure, and as a result, the above-mentioned gap is enlarged, causing an increase in the amount of leakage and impairing the sealing performance. In addition, abnormal deformation of the gland packing B causes problems such as shortening of the packing life.

On the other hand, anticipating in advance that the gap will be enlarged due to pressure imbalance, the tightening pressure by the gland packing holder C can be increased to cause the inner periphery of the gland packing B to bulge toward the rotation axis D side. Although this is done in this way, the tightening surface pressure of the gland packing B against the rotating shaft D increases,
This has the disadvantage that the power loss increases, and the lubricating function of the sealing fluid deteriorates, resulting in abnormal wear or seizure of the seal portion due to dry operation.

In addition, the higher the sealing fluid pressure, the higher the gland packing B.
There is also the problem that it is difficult to seal high-pressure sealing fluid because the abnormal deformation is large and the amount of leakage is large.

Therefore, segment seals have been proposed to ensure pressure balance by applying sealing fluid pressure in the axial and radial directions, but this type of seal has an extremely complex structure and
It has drawbacks such as poor assemblability and poor practical reliability.

The present invention was developed in view of the above circumstances, and can ensure pressure balance with a simple structure, thereby avoiding abnormal deformation of the gland packing and preventing deterioration of sealing performance.
The purpose of the present invention is to extend the life of the gland packing, easily seal high-pressure sealing fluid, and provide a structure of a gland packing box that is easy to assemble and has high reliability.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides a structure that provides a gap between the inner surface of a gland packing box and the sealing fluid side end surface and outer circumferential surface of the gland packing, and between the packing holder and the gland packing. A sealing fluid introduction means is provided for introducing a sealing fluid between the sealing fluid side end face, the outer circumferential surface, and the sealing presser side end face, respectively, and applying the sealing fluid pressure to the sealing fluid side end face, the outer circumferential surface, and the sealing presser side end face.

[Function] According to the present invention, the pressure of the sealing fluid introduced by the sealing fluid introduction means is also applied to the sealing fluid side end face, outer circumferential face, and sealing presser side end face of the gland packing. . This ensures pressure balance and avoids abnormal deformation of the gland packing.

[Example] Hereinafter, the present invention will be described in detail based on an example shown in the drawings.

FIG. 1 is a cross-sectional view of the first embodiment, and in the figure, 1 is a packing box, 2 is a plurality of gland packings, and these gland packings 2 are fitted onto the rotating shaft 3 within the packing box. Between the inner surface 11 of the packing box 1 and the sealed fluid side end surface 2A of the gland packing 2, between the inner peripheral surface 12 of the packing box 1 and the outer peripheral surface 2B of the gland packing 2, and the end surface of the gland packing 2 on the packing presser side. Sealing fluid introduction means 4 is interposed between 2C and the seal holder 5.

The sealing fluid introducing means 4 is made of a pressure-formed metal wire knitted net or a porous body having continuous pores such as a sintered material, and includes an annular introducing means 4A having an approximately L-shaped cross section, and an annular introducing means 4A having an approximately L-shaped cross section. It consists of an introduction means 4B formed in a square ring shape. Therefore, the assembly is performed by inserting one of the introducing means 4A into the packing box 1, and then inserting the plurality of gland packing boxes 2.
A is charged, and then the other introducing means 4B is charged.

The packing presser foot 5 has an annular protrusion 5 at its tip.
A is formed, and a sealing fluid introduction means 4B is fitted onto this annular projection 5A. For this purpose, the gland packing 2 is locally strongly pressed in the axial direction by the tip of the annular protrusion 5A of the packing holder 5 with a predetermined tightening pressure on the inner circumference of the packing holder side end surface 2C, and is sealed. The front end pressing surface 5B of the packing holder 5 is tightened via the fluid introduction means 4B with a predetermined tightening pressure, and most of the area excluding the inner circumference of the packing holder side end surface 2C is tightened by the shaft with a pressing force slightly smaller than the above-mentioned pressing force. It will be pushed in the direction. As a result, a gap (not shown) is formed between the outer periphery of the rotating shaft 3 and the inner periphery of the gland packing 2 to allow a slight leakage of the sealing fluid. The leaking fluid is provided with a lubricating function and a cooling function to prevent abnormal wear of the rotating shaft 2 or seizure due to dry operation and to seal the rotary shaft 2.

According to the configuration, the sealing fluid is connected to the rotation shaft 3 described above.
In the process of leaking through the gap formed between the outer periphery of the gland packing 2 and the inner periphery of the gland packing 2, the pressure is applied to the inner periphery of the gland packing 2, and
The sealing fluid is introduced into the continuous pores of the sealing fluid introduction means 4A, 4B made of pressure-formed metal wire knitted mesh, sintered material, or the like. As a result, the pressure is applied to each of the sealing fluid side end surface 2A, the outer circumferential surface 2B, and the packing presser side end surface 2C of the gland packing 2 in the distribution state shown in FIG. In other words, Grand Packkin 2
The pressure balance will be ensured. Therefore, the gland packing 2 does not undergo abnormal deformation as in the conventional case, that is, deformation in which the inner periphery is expanded in diameter by the sealing fluid pressure. Therefore, it is possible to avoid the above-mentioned gap from expanding and to prevent the sealing performance from deteriorating, and since the gland packing 2 is not abnormally deformed, the life of the gland packing can be extended.

Further, by ensuring the pressure balance, the expansion of the gap is avoided, so that it is no longer necessary to increase the tightening pressure by the packing presser 5 in advance in anticipation of the expansion of the gap, as is the case in the past. Therefore, the tightening surface pressure of the gland packing 2 against the rotating shaft 3 increases, resulting in an increase in power loss, abnormal wear due to a decrease in the lubrication and cooling functions of the sealing fluid, or seizure of the seal part due to dry operation, etc. This inconvenience can be avoided. These features include a structure in which the inner circumferential portion of the gland packing 2 on the sealing presser side end surface 2C is locally pressed with the tip of the annular projection 5A formed at the tip of the packing presser 5;
That is, it is also promoted by a structure in which the tightening pressure is increased with a small tightening load.

Furthermore, even if the sealing fluid pressure increases, the aforementioned pressure balance is ensured by the high-pressure fluid.
A reliable seal can be achieved regardless of the level of fluid pressure.

FIG. 3 shows a second embodiment of the invention. In this embodiment, the sealing fluid introduction means 4 is interposed between the inner surface 11 of the packing box 1 and the sealing fluid side end surface 2A of the gland packing 2.
A1, sealing fluid introducing means 4A2 and gland packing 2 interposed between the inner circumferential surface 12 of packing gland 1 and the outer circumferential surface 2B of gland packing 2;
The seal fluid introduction means 4B is interposed between the seal presser side end surface 2C and the seal presser 5, and is formed by displacing the seal contact surfaces of the seal fluid introduction means 4A1 and 4B in the axial direction. are doing. Therefore, since the gland packing 2 is clamped and displaced in the axial direction by the sealing fluid introducing means 4A1, 4B provided with an axially displacing portion, the first
In addition to achieving the same effects as in the embodiment, the fluid introduced into the gap and the sealing fluid introduction means 4A2 also flows into the axial overlap region on the inner circumferential surface of the gland packing 2 as the rotating shaft 3 rotates. This means that this part will be more effectively lubricated and cooled.

Note that the cross-sectional shape of the annular protrusion 5A formed at the tip of the packing presser 5 may be circular as shown in FIG. 1, flat as shown in FIG. 2, or as shown in FIG. 4. It may also be formed into a serrated shape.

In the first and second embodiments, the sealing fluid introducing means 4 is formed of a pressure-formed metal wire knitted net or a porous body having continuous pores such as a sintered material. The present invention is not limited only to the above-mentioned embodiment, and in the case of the first embodiment, as shown in FIGS. A large number of dense grooves 4a are formed radially, and a large number of grooves 4b with close circumferential intervals are formed along the axial direction on the inner circumferential surface 12 of the packing box 1, as shown in FIGS. 5A and 6. In addition, as shown in FIGS. 5A and 7, a sealing fluid introduction means 4 is constructed by forming a large number of radially spaced grooves 4c at close intervals in the circumferential direction on the front end pressing surface 5B of the packing presser 5. You can also use it as

In the case of the second embodiment, as shown in FIGS. 8A and 8B, a neck bushing 6 is provided with a neck bushing 6 in which a large number of grooves 4a with close circumferential intervals are formed radially on the surface facing the gland packing 2. 1
As shown in FIGS. 8A and 9,
In the inner circumferential surface 12 of the packing box 1, a large number of grooves 4b with close circumferential intervals are formed along the axial direction, and as shown in FIGS. 8A and 10,
The sealing fluid introducing means 4 may be constructed by forming a large number of radially spaced grooves 4c closely spaced in the circumferential direction on the front end pressing surface 5B of the packing presser 5.

[Effects of the Invention] As explained above, according to the present invention, there are Since the structure is equipped with a sealing fluid introducing means for introducing sealing fluid into each of the spaces between the sealing fluid and applying the sealing fluid pressure to the sealing fluid side end face, the outer circumferential face, and the packing presser side end face, the sealing fluid introducing means The pressure of the sealing fluid thus introduced is also applied to the sealing fluid side end surface, the outer peripheral surface, and the packing presser side end surface of the gland packing. As a result, the pressure balance is ensured, and abnormal deformation does not occur in the gland packing. This prevents the gap between the inner periphery of the gland packing and the outer periphery of the rotating shaft from increasing, thereby preventing deterioration of sealing performance. This can be prevented and the life of the gland packing can be extended.

In addition, since there is no need to unnecessarily tighten the gland packing with the packing holder and prevent it from bulging toward the rotating shaft, power loss may increase, abnormal wear may occur due to a decrease in the lubrication function and cooling function of the sealing fluid, or sealing may occur due to dry operation. No problems such as burning of parts occur.

Further, it has advantages such as being able to reliably seal regardless of the value of the sealing fluid pressure, having a simple structure, excellent assemblability, and high reliability.

[Brief explanation of the drawing]

1 to 10 show embodiments of the present invention, FIG. 1 is a sectional view of the first embodiment, FIG. 2 is an explanatory diagram of the state of pressure distribution applied to the gland packing, and FIG. FIG. 4 is an enlarged sectional view showing a modified example of the tip of the packing presser; FIG. 5 is a sectional view of the second embodiment;
Figures A to 7 are explanatory diagrams showing other embodiments of the sealing fluid introducing means that can be employed in the first embodiment, and Figure 8A
10 to 10 are explanatory diagrams showing other embodiments of the sealing fluid introduction means that can be adopted in the second embodiment, and FIG.
The figure is a sectional view of the conventional example, and FIG. 12 is an explanatory diagram of the state of pressure distribution applied to the conventional gland packing. 1... Packing box, 2... Gland packing, 2A... Sealed fluid side end surface, 2B... Outer peripheral surface, 2C
... End face on the packing presser side, 3... Rotating shaft, 4... Sealing fluid introduction means.

Claims (1)

[Claims] 1 A gland packing box into which a gland packing is inserted which is pressed in the axial direction by a packing holder to form a seal against the rotating shaft,
A sealing fluid is introduced between the inner surface of the gland packing box and the sealing fluid side end surface and the outer circumferential surface of the gland packing, and between the packing presser and the sealing presser side end surface of the gland packing. A structure of a gland packing box characterized by comprising a sealing fluid introducing means for applying pressure to the sealing fluid side end face, the outer peripheral surface and the packing presser side end face.