JPH01320375A - Grand packing - Google Patents

Abstract

PURPOSE:To better an assembling property as well at a low cost by constituting plural packings by the hard packing forming an annular gap in the space with a rotary shaft and the soft packing arranged between these hard packings. CONSTITUTION:A hard packing 2 and the soft packing 3 arranged between these hard packings are outer-fitted to a rotary shaft 4 in a packing box 1. A packing presser 5 fits its tip part to the opening part of the packing box 1 and pinches the packing group consisting of the hard packing 2 and soft packing 3 with the pinching force in the axial direction by a fastening means. The generations of the abnormal wear of the rotary shaft and the seizure of a seal part are prevented, the assembling property is bettered and a low cost can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a gland packing applied to a shaft seal of equipment such as a bomb stirrer.

[Prior art] As a conventional general gland packing, the 12th
As shown in the figure, a plurality of gaskets 2 are formed in such a shape that their end faces are perpendicular to and uniformly intersect with the axis of the rotating shaft 21.
There is one in which 2...- are clamped with axial clamping force. However, with such a gland packing, a lubricating and cooling fluid cannot be supplied to the contact portion between the packing 22 and the rotating shaft 21, resulting in a problem of seizure occurring under high speed and high pressure conditions.

As a means to solve these problems, the applicant proposed in Japanese Patent Application No. 61-266469, which was filed prior to the present application, a packing 33 that is fitted around the rotating shaft 32 inside a packing box 31, as shown in FIG.・Put the packing 3 on the clamping surface of the packing clamping member 34.34 that clamps the
A structure of a gland packing box is proposed in which at least one displacement portion 34a, 34a for partially displacing the three... in the axial direction is formed. If the structure of the gland packing box shown in FIG. 13 is adopted and a plurality of packings 33... An annular gap 36.3 formed with the outer peripheral surface of the rotating shaft 32
6 is on the right side in the circumferential direction and overlaps the inner peripheral surface of the packing 33. Therefore, as the rotation shaft 32 rotates, the fluid sent into the gap 36,
It is forcibly fed into the overlapping inner circumferential surfaces of ..., and as a result, the lubrication and cooling functions can be significantly improved.

[Problems to be Solved by the Invention] However, the gland packing box as shown in FIG. 13 has a problem in terms of cost because the manufacturing cost of the packing clamping member in which the displacement part is formed is high, and also the gland packing box shown in FIG. The attachment member is made of metal, hard synthetic resin, etc. and has extremely poor deformability, so there is also the problem that it is impossible to attach it to the rotating shaft when it is formed into a ring shape. . Furthermore, since the packing clamping member cannot obtain a large frictional force with the packing box, there is a risk that the packing member will rotate together with the rotating shaft. There was also the hassle of having to set up a

The present invention was made in view of the above-mentioned circumstances, and an object of the present invention is to provide a gland packing that has high lubrication and cooling functions, can be made at a relatively low cost, and is easy to assemble. There is.

[Means for Solving the Problems] In order to achieve the above object, the gland packing according to the present invention has a plurality of packings, in which at least one displacement part partially displaced in the axial direction is formed on the end face, and the gland packing is connected to the rotating shaft. It is characterized by being composed of hard packings that form an annular gap therebetween, and soft packings arranged between the hard packings.

[Function] The gland packing as described above is attached without the inner circumferential surface of the hard packing coming into pressure contact with the outer circumferential surface of the rotating shaft. Since a part of the annular gap formed by the inner circumferential surface of the hard packing and the outer circumferential surface of the rotating shaft overlaps a part of the inner circumferential surface of the soft packing in the circumferential direction, as the rotating shaft rotates, The fluid is forced into the inner peripheral surface of the overlapping soft packing. Further, the outer peripheral surface of the hard packing is pressed into contact with the packing box and is integrated with the packing box.

[Embodiment] FIG. 1 is a longitudinal sectional view showing an embodiment of the gland packing according to the present invention, and in the figure, l denotes a packing box, which is constructed, for example, at one end of a pump casing. Inside this packing box l, hard packing 2
．． A gasket 3 disposed between the hard gaskets 2 and 2 is fitted onto the rotary shaft 4. Reference numeral 5 denotes a packing holder, the tip of which is fitted into the opening of the packing box l, and the packing group consisting of the hard packing 2.2 and the soft packing 3 is held by a clamping force in the axial direction by a tightening means (not shown). It's stuck. This will be explained in more detail below.

The hard packing 2 is a metallic packing made by twisting lead alloy foil, and as shown in FIG.
By attaching a packing material 2° to a mold consisting of a mouth, inserting a displacement jig E between one end surface and the mold material C, and pressing the mold material C, one end surface is removed as shown in FIG. It is manufactured in a ring shape in which a displacement portion 2a is partially displaced in the axial direction. Moreover, when this hard packing 2 is installed in the packing box L, the gap between it and the packing box 1 is small, and the gap with the rotating shaft 4 is maintained even after being clamped, as will be described later. It is formed to be slightly larger.

The soft packing 3 is a braided packing in which carbonized fibers are impregnated with PTFE (polytetrafluoroethylene resin), and using a mold similar to that shown in Fig. 6, a displacement jig is installed on both end surfaces of the soft packing. By interposing, as shown in FIG. 8, a displaced portion 3a partially displaced in the axial direction is formed on both end faces.
The displacement jig used to manufacture the soft packing 3, which is manufactured in a ring shape with a ring 3a formed thereon, has approximately the same amount of axial displacement as the displacement jig E used to manufacture the hard packing 2. It is. However, this soft packing 3
The gap with the rotating shaft 4 is set to be smaller than that of the hard packing 2 so that the inner circumferential surface of the hard packing 2 comes into close contact with the outer circumferential surface of the rotating shaft 4 after being clamped by the tightening function.

The packing presser 5 is formed in such a shape that its tip surface perpendicularly and uniformly intersects the axis of the rotating shaft 4, and this tip surface is not formed with the displacement portion 2a of one of the hard packings 2. Abuts against the end face over the entire end face.

With the above configuration, when the packing presser 5 is pressed toward the packing group by a tightening function (not shown), the hard packing 2.
The outer circumferential surface of 2 is pressed against the inner circumferential surface of the packing box l and is integrated with this packing box 1, while the inner circumferential surface has a large gap between it and the rotating shaft 4 when installed.
It faces the outer circumferential surface of the rotating shaft 4 with the annular gap 6°7 remaining.

On the other hand, most of the inner circumferential surface of the soft packing 3 is in close contact with the outer circumferential surface of the rotating shaft 4, but since the displaced portions 3a, 3a are formed on both end surfaces, the displaced portion 3a of the inner circumferential surface is , 3
The region indicated by diagonal lines x and Y in FIG. 2, which extend from a to the transitional portion to the undisplaced portion, overlaps the gap 6 or 7 on the inner peripheral side of the hard packing 2.2. for that,
As the rotation shaft 4 rotates, the fluid in the gap 6.7
The leakage fluid is forcibly sent to the areas indicated by X and Y, and a large amount of fluid is evenly distributed from the areas X and Y to the seal portion 8, thereby improving the lubrication and cooling functions.

FIG. 3 shows another embodiment of the invention. In this embodiment, like the soft packing 3, a hard packing 2A having displacement parts 2Aa, 2Aa formed on both end faces is arranged in the center, and this hard packing 2A and the above-mentioned first packing arranged at both ends.
A soft packing 3.3 is sandwiched between hard packing 2.2 similar to that used in the example. In this way, by using a hard packing with displacement parts formed on both end faces.

A gland packing with improved sealing performance can be obtained by increasing the number of packing stages.

By the way, in each of the above embodiments, an example is shown in which a packing is used in which one displacement part is formed on one end face, but as in the third embodiment shown in FIG. 4, three displacement parts are formed on one end face. Hard gaskets 2° and 2° formed with portions 2a' or 2b° (only one location shown), or similarly three displaced portions 3a' or 3b° (both shown only one location) on one end surface.
A soft packing with a displacement of 3° may be used, or a hard and soft packing with a displacement of more than 3° may be used. When the displacement portions are provided at two locations on the circumference as in this third embodiment, as shown in FIG. Displacement part 3a°.

On the end face side having 3a', this convex displacement part 3a',
3a', and in the area indicated by L, and on the end face side having the concave displacement parts 3b', 3b', a diagonal line Yl corresponding to a position shifted from the concave displacement parts 3b', 3b' toward the rotation direction side. , Y2, a gap 6°7 formed between the hard packing 2°, 2° and the rotating shaft 4, respectively.
overlap. In this way, by increasing the number of displacement parts formed on one end face, the fluid can spread more evenly to the contact surface between the soft packing and the rotating shaft.

In the above embodiment, the hard packing is made of twisted lead alloy foil, but aluminum foil may be used instead of lead alloy foil, or lead wire, copper wire, stainless steel The hard packing may be made of braided fibers, etc., or a plastic packing kneaded with graphite, rubber, etc. may be used as the hard packing. It is desirable that the material has such hardness that it will not be deformed by fluid pressure when used in a state in which it is held between two.

On the other hand, soft packing needs to be a packing that contains a large amount of oil and is easily deformed when tightened with a packing presser.In addition to the above-mentioned braided packing made of carbonized fiber impregnated with PTFE, aramid fiber impregnated with PTFE is used. Braided packing etc. are suitable.

Further, the amount of displacement in the axial direction of the hard and soft packings in each gland packing, that is, the displacement t shown in FIGS. 7 and 8, is set to be 3 times or less, preferably 1 time or less, the packing width T. This is because if the amount of displacement is too large, it will not be possible to ensure sufficient contact between the inner circumferential surface of the soft packing and the outer circumferential surface of the rotating shaft.

[Experimental example] The gland packing of the first embodiment of the present invention shown in FIG. 1 above and the conventional gland packing shown in FIG.
Comparison of packing temperature, fluid leakage amount, and gravity torque in 9th A
As shown in FIGS. 1 to 11, as described above, the hard packing is made by twisting lead alloy foil, and the soft packing is a braided packing made of PTFE impregnated with carbon fiber. Other test conditions are as follows.

■Fluid type, fluid pressure and fluid temperature Industrial water 5 Kg/cm" 20℃■Rotation speed 1910 R, P, M ■Rotating shaft diameter φ100 mm ■Inner diameter of packing box φ129 mm The conventional gland packing is No. 9B As shown in the figure,
The gasket temperature rose to about 50°C for nearly 3 hours after the start of use, and as shown in Figure 10B, an extremely large amount of fluid leaked, especially after the start of use.
As shown in Fig. 9A, the gland packing according to the present invention maintains a packing temperature of approximately 25°C or less at all times, and as shown in Fig. 10A, the amount of fluid leakage immediately after the start of use is lower than that of the conventional example. Furthermore, as shown in Fig. 11, the conventional product exhibits a high level and unstable change in gravitational torque, whereas the ground packing according to the present invention exhibits a low level and extremely It is assumed that the gland packing is stable and that lubrication is performed well.6 [Effects of the Invention] As is clear from the above explanation, the gland packing according to the present invention has significantly improved lubrication and cooling functions. Therefore, abnormal wear of the rotating shaft or seizure of the seal portion due to dry operation can be prevented, and power loss can be kept as small as possible. In addition, existing packing boxes and packing holders can be used as they are, and the ease of assembly is no different from conventional products, so there is little increase in production costs.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional front view showing the first embodiment of the gland packing according to the present invention, Fig. 2 is a developed view illustrating the state of the inner peripheral surface of the soft packing, and Fig. 3 is a longitudinal sectional front view of the second embodiment. figure,
FIG. 4 is a longitudinal cross-sectional view of the third embodiment. Fig. 5 is a developed view explaining the state of the inner peripheral surface of the soft packing, Fig. 6 is a vertical sectional view of the mold, Fig. 7 is a longitudinal sectional view of the hard packing, and Fig. 8 is a vertical sectional view of the soft packing. , FIG. 9A is a graph showing changes in the gland packing temperature of the gland packing according to the present invention, and FIG. 9B is a graph showing changes in packing temperature of the gland packing according to the present invention.
The figure is a graph showing the change in gasket temperature of the conventional product.
Figure A is a graph showing changes in the amount of fluid leakage of the gland packing according to the present invention, Figure 10B is a graph showing changes in the amount of fluid leakage of the conventional product, and Figure 11 is a graph showing the gravitational torque of the gland packing according to the present invention and the conventional product. Graphs for comparison, FIG. 12 is a vertical cross-sectional view of a conventional product, and FIG. 13 is a vertical cross-sectional view of another conventional product. l... Patsukin box, -'2.2A, 2
°...hard packing, 2a, 2Aa, 2a', 2b'...displacement part. 3.3°...Soft packing, 3a, 3a', 3b'-
・・Displacement part, 4・・・Rotation axis

Claims (1)

[Claims] (1) In a gland packing in which a plurality of packings externally fitted around a rotating shaft are sandwiched by axial clamping force in a packing box, at least one displacement portion where the plurality of packings are partially displaced in the axial direction on an end face. What is claimed is: 1. A gland packing comprising: a hard packing which forms an annular gap with the rotating shaft; and a soft packing disposed between the hard packing.