JPH0781642B2 - Gland packing - Google Patents

Description

TECHNICAL FIELD The present invention relates to a gland packing applied to a shaft sealing portion of equipment such as a pump and a stirrer.

[Prior Art] As a conventional general gland packing, as shown in FIG. 12, a plurality of packings 22 ... Formed in a shape in which the end face is perpendicular to the axis of the rotating shaft 21 and uniformly intersects each other. Some of them are clamped by a clamping force in the axial direction. However, in such a gland packing, a fluid for lubrication and cooling cannot be supplied to the contact portion between the packing 22 and the rotary shaft 21, and there is a problem that seizure occurs under high speed and high pressure conditions.

As a means for solving such a problem, the applicant, in the Japanese Patent Application No. 61-266469 filed prior to the present application, as shown in FIG. 13, uses a packing 33 ... Packing clamp member 3 that clamps in the axial direction
A structure of a gland packing is proposed, in which at least one displacement portion 34a, 34a for partially displacing the packing 33 in the axial direction is formed on the sandwiching surfaces of 4, 34. Adopting the structure of the gland packing shown in FIG. 13, the packing sandwiching member
When a plurality of packings 33 ... Are sandwiched between 34, 34, a part of the annular gaps 36, 36 formed by the inner peripheral surfaces of the packing sandwiching members 34, 34 and the outer peripheral surface of the rotary shaft 32 are circular. Since the fluid is introduced into the gaps 36, 36 in the circumferential direction so as to overlap the inner circumferential surface of the packing 33, the fluid is forced to the overlapping inner circumferential surface of the packing 33 as the rotating shaft 32 rotates. As a result, the lubrication function and the cooling function can be significantly improved.

[Problems to be Solved by the Invention] However, in the gland packing as shown in FIG. 13, the manufacturing cost of the packing sandwiching member having the displacement portion is high and there is a problem in cost. Further, since the packing sandwiching member is made of metal, hard synthetic resin, or the like due to its performance and is extremely poor in deformability, it cannot be mounted on the rotary shaft in a ring-shaped state. There is also the problem that there is. Further, since the packing sandwiching member cannot obtain a large frictional force with the packing box, there is a risk that it will rotate together with the rotating shaft. To prevent this, a rotation stop pin integrated with the packing box. There was also the annoyance of having to provide.

The present invention has been made in view of the above circumstances, and while keeping the manufacturing cost low, it is possible to secure a high lubrication function and a cooling function while maintaining a high lubrication function and a high speed while being excellent in assemblability without requiring a rotation stopping means or the like. An object of the present invention is to provide a gland packing that can prevent the occurrence of baking even under high pressure conditions.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the gland packing according to the present invention has a plurality of packings, which are packaged on a rotating shaft in a packing box and are clamped by a clamping force in the axial direction, on an end surface. At least one displacement portion is formed in the circumferential direction partially displaced in the axial direction, the outer peripheral surface is in pressure contact with the inner peripheral surface of the packing box, and a hard packing that forms an annular gap with the rotating shaft. And a soft packing which is arranged between the hard packings and whose outer peripheral surface and inner peripheral surface are in close contact with the inner peripheral surface of the packing box and the outer peripheral surface of the rotary shaft, respectively. It is a thing.

[Operation] In the gland packing of the present invention, the outer peripheral surface is in pressure contact with the inner peripheral surface of the packing box, and a hard packing that forms an annular gap between the outer peripheral surface and the inner peripheral surface of the packing box. At least one axial partial displacement portion formed on the end surface of the hard packing, which is made of a combination with a soft packing disposed between the hard packings so as to be in close contact with the inner peripheral surface and the outer peripheral surface of the rotary shaft. Due to this, axial displacement parts are also formed on both end faces of the soft packing,
Part of the annular space between the inner peripheral surface of the hard packing and the outer peripheral surface of the rotating shaft will overlap a part of the inner peripheral surface of the soft packing in the circumferential direction, thereby,
The fluid sent to the annular gap is forcibly sent to the inner peripheral surface of the overlapping soft packing with the rotation of the rotating shaft, so that the lubricating function and the cooling function are sufficiently ensured. Further, since the partial displacement portion is formed on the hard packing, it is possible to use the existing packing holding member and packing box such as a packing retainer having poor deformability such as metal or hard synthetic resin. In addition, the outer peripheral surfaces of the packings are pressed against the inner peripheral surface of the packing box, and the large frictional force between them prevents them from co-rotating with the rotating shaft. Assembly is easy, including mounting on the rotating shaft.

[Embodiment] FIG. 1 is a longitudinal sectional view showing an embodiment of a gland packing according to the present invention. In the drawing, reference numeral 1 is a packing box, which is formed at one end of a pump casing, for example. In this packing box 1, a hard packing
A soft packing 3 arranged between the hard packings 2, 2 and the hard packings 2, 2 is fitted onto the rotary shaft 4. A packing retainer 5 has a distal end fitted into the opening of the packing box 1, and a packing group consisting of the hard packings 2 and 2 and the soft packing 3 is pressed by an unillustrated tightening means in the axial direction. It is sandwiched. Further details will be given below.

The hard packing 2 is a metallic packing obtained by twisting a lead alloy foil, and, as shown in FIG. 6, four mold materials A to form inner and outer peripheral surfaces and both end surfaces of the hard packing 2.
By mounting the packing material 2'on the mold made of D and inserting the displacement jig E between one end surface and the mold material C to press the mold material C, as shown in FIG. It is manufactured in a ring shape in which a displacement portion 2a partially displaced in the axial direction is formed. Further, when the hard packing 2 is mounted in the packing box 1, the clearance between the rigid packing 2 and the packing box 1 is small, and the clearance with the rotating shaft 4 is maintained even after the bonding as described later. It is formed to be slightly larger.

The soft packing 3 is a braided packing in which PTFE (tetrafluoroethylene resin) is impregnated with carbonized fiber. Using a mold similar to that shown in FIG. 6, displacement jigs are provided on both end surfaces of the soft packing. By interposing, as shown in FIG.
This soft packing 3 is manufactured in a ring shape in which displacement portions 3a, 3a partially displaced in the axial direction are formed on both end surfaces.
The displacement jig used in the production of No. 1 has a displacement amount in the axial direction substantially equal to that of the displacement jig E used in the production of the hard packing 2. However, the gap between the soft packing 3 and the rotary shaft 4 is set smaller than that of the hard packing 2 so that the inner peripheral surface of the soft packing 3 comes into close contact with the outer peripheral surface of the rotary shaft 4 after being clamped by the tightening function. Has been done.

The packing retainer 5 is formed in a shape in which the tip end surface thereof intersects the axis of the rotating shaft 4 vertically and uniformly, and the tip end surface does not have the displacement portion 2a of one of the hard packings 2. Abut on the end face over the entire end face.

When the packing retainer 5 is pressed toward the packing group side by the not-shown tightening function with the above-mentioned configuration, the hard packing 2, 2
The outer peripheral surface of the ring is pressed against the inner peripheral surface of the packing box 1 to be integrated with the packing box 1, while the inner peripheral surface has a large gap between the inner peripheral surface and the rotary shaft 4 at the time of mounting. It faces the outer peripheral surface of the rotating shaft 4 while leaving 6 and 7.

On the other hand, in the soft packing 3, most of the inner peripheral surface is in close contact with the outer peripheral surface of the rotating shaft 4, but since the displacement portions 3a, 3a are formed on both end surfaces, the displacement portion 3a of the inner peripheral surface is formed. , 3a to the non-displaced portion of the transition, the area shown by diagonal lines X and Y in FIG. 2 overlaps with the voids 6 or 7 on the inner peripheral side of the hard packings 2, 2. Therefore, the fluid in the voids 6 and 7 is forcibly sent as a leaking fluid to the area indicated by X and Y as the rotary shaft 4 rotates, and further, the fluid is sealed from the sent areas X and Y. Since a large amount of fluid is evenly distributed to the portion 8, the lubrication function and the cooling function are improved.

FIG. 3 shows another embodiment of the present invention. In this embodiment, similarly to the soft packing 3, the hard packing 2A having the displacement portions 2Aa, 2Aa formed on the end surfaces on both sides is arranged in the central portion, and the hard packing 2A and the above-described first embodiment arranged on both ends are arranged. Soft packings 3, 3 are respectively sandwiched between the same hard packings 2, 2 as used. In this way, by using the hard packing with the displacement parts formed on both end surfaces,
It is possible to obtain a gland packing having an improved sealing property by increasing the number of packing stages.

By the way, in each of the above-mentioned embodiments, an example in which a packing having one displacement portion formed on one end face is used is shown. However, as in the third embodiment shown in FIG. 4, there are two displacements on one end face. Hard packing 2 ', 2'having a part 2a' or 2b '(both shown at only one place), or a soft material having two displacement parts 3a' or 3b '(both shown at only one place) on one end face The packing 3'may be used, or hard and soft packings having a displacement portion larger than that may be used. When the displacement portions are provided at two locations on the circumference as in the third embodiment, the inner peripheral surface of the soft packing 3'is provided at two locations on each end surface, that is, in a convex shape, as shown in FIG. On the end face side having the displacement portions 3a ′, 3a ′, in the regions indicated by the diagonal lines X ₁ , X ₂ corresponding to the convex displacement portions 3a ′, 3a ′, and on the end face side having the concave displacement portions 3b ′, 3b ′. the concave displacement portion 3b ', 3b' in the region indicated by oblique lines Y _1, Y ₂ corresponding to the position deviated from the rotational direction, respectively rigid packing 2 ', 2' gap formed between the rotary shaft 4 and
Overlaps to 6,7. In this way, by increasing the number of displacement portions formed on one end face, the fluid can be evenly distributed to the contact surface between the soft packing and the rotary shaft.

In the above embodiment, the hard packing is formed by twisting a lead alloy foil, but an aluminum foil may be used instead of the lead alloy foil, a lead wire, a copper wire, and a stainless steel. It may be formed by braiding fibers or the like. Further, a plastic packing obtained by kneading graphite, rubber or the like may be used as the hard packing. That is, it is desirable that the hard packing has such a hardness that it is not deformed by fluid pressure in a use state in which it is sandwiched by a sandwiching pressure in the packing box in the axial direction.

On the other hand, the soft packing needs to be a packing that contains a large amount of oil and can be easily deformed by tightening the packing pressing. Braided packing or the like is suitable.

Further, the axial displacement of the hard and soft packings of the individual gland packings, that is, the displacement t shown in FIGS. 7 and 8 is 3 times or less, and preferably 1 time or less, the packing width T. This is because if the displacement amount is too large, it becomes impossible to secure a sufficient contact portion between the inner peripheral surface of the soft packing and the outer peripheral surface of the rotary shaft.

[Experimental Example] Fig. 9A is a comparison of the packing temperature, the fluid leakage amount, and the gravity torque between the gland packing of the first embodiment of the present invention shown in Fig. 1 and the conventional gland packing shown in Fig. 12. ~
It is shown in FIG. As described above, twisted lead alloy foil is used as the hard packing, and braided packing in which PTFE is impregnated with carbon fiber is used as the soft packing. Other test conditions are as follows.

Type of fluid, gland packing of fluid pressure and fluid temperature industrial water 5Kg / cm ² 20 ℃ rpm 1910R.PM rotary shaft axis diameter φ100mm packing box inner diameter φ129mm conventional products, as shown in FIG. 9B, used after the start 3 The packing temperature rises to about 50 ° C. over a period of time, and as shown in FIG. 10B, an extremely large amount of fluid leakage has occurred particularly after the start of use, whereas the gland packing according to the present invention has a structure shown in FIG. 9A. As shown in Fig. 10, the packing temperature is constantly suppressed below 25 ° C, and the 10A
As shown in the figure, the amount of fluid leakage immediately after the start of use is only about half that in the conventional example. Also, as shown in FIG.
The gravity torque of the conventional product also shows a high level and unstable change, whereas the gland packing according to the present invention is at a low level and extremely stable, and it is presumed that the lubrication is well performed. To be done.

[Effects of the Invention] As described above, according to the present invention, it is possible to use the existing packing clamping members such as a metal retainer or a hard synthetic resin with poor deformability such as packing retainers and packing boxes as they are. In addition, since it is configured to prevent co-rotation with the rotating shaft with a large frictional force obtained by pressing the outer peripheral surfaces of multiple packings against the inner peripheral surface of the packing box, the manufacturing cost can be kept low and It is easy to assemble including mounting on the rotating shaft because no rotation prevention means is required, and at least one axial partial displacement part formed on the end face of the hard packing can be applied to both end faces of the soft packing. By forming a displacement part in the axial direction,
A part of the annular space between the inner peripheral surface of the hard packing and the outer peripheral surface of the rotary shaft is overlapped with a part of the inner peripheral surface of the soft packing in the circumferential direction, and is thereby fed into the annular space. With the rotation of the rotating shaft, it is possible to ensure sufficient lubrication and cooling functions, such as forcing the fluid to the inner peripheral surface of the overlapping soft packing, which results in abnormal wear of the rotating shaft. Alternatively, there is an effect that it is possible to prevent the sealing portion from being burned by the dry operation and to suppress the power loss as small as possible.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing a first embodiment of a gland packing according to the present invention, FIG. 2 is a development view illustrating a state of an inner peripheral surface of a soft packing, and FIG. 3 is a vertical sectional front view of the second embodiment. Figure,
FIG. 4 is a vertical cross-sectional view of the third embodiment, FIG. 5 is a development view for explaining the state of the inner peripheral surface of the soft packing, FIG. 6 is a vertical cross-sectional view of the mold, and FIG. 7 is a vertical cross-section of the hard packing. Fig. 8 is a longitudinal sectional view of the soft packing, Fig. 9A is a graph showing a change in packing temperature of the grant packing according to the present invention, Fig. 9B is a graph showing a change in packing temperature of a conventional product, and Fig. 10A. Is a graph showing the change in the amount of fluid leakage of the gland packing according to the present invention, FIG. 10B is a graph showing the change in the amount of fluid leakage of the conventional product, and FIG. 11 is a comparison of the gravity torque between the gland packing according to the present invention and the conventional product. FIG. 12 is a vertical sectional view of a conventional product, and FIG. 13 is a vertical sectional view of another conventional product. 1 ... Packing 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. A gland packing formed by sandwiching a plurality of packings fitted onto a rotary shaft in a packing box with a sandwiching force in the axial direction, wherein the plurality of packings are circumferentially partially displaced on an end face in the axial direction. Between at least one displacement portion is formed in the direction and the outer peripheral surface is in pressure contact with the inner peripheral surface of the packing box, and forms an annular space between the rotary shaft and the hard packing. A gland packing, which is arranged and comprises a soft packing whose outer and inner peripheral surfaces are in close contact with the inner peripheral surface of the packing box and the outer peripheral surface of the rotary shaft, respectively.