JPH051736Y2 - - Google Patents

Description

[Detailed description of the invention] <Field of industrial application> The present invention relates to a shaft sealing device using a seal disk integrated with a rotor shaft and a pair of seal rings provided in a housing surrounding the seal disk. It is suitable for use in a centrifugal separator that separates a liquid from fine powder dispersed in the liquid.

<Prior art> In a centrifugal separator, multiple types of substances with different properties are separated using differences in their specific gravity, and as shown in Figure 2, which shows the cross-sectional structure of the bearing part, An impeller support shaft (hereinafter referred to as a rotor shaft) 1 is rotatably supported by a bearing box 3 via a bearing 2 . Centrifugal force is generated by this driving rotation of the rotor shaft 1, and the substances to be separated flow toward both ends of the rotor shaft 1 along the inclined inner peripheral surface of the drum (not shown) according to the difference in their specific gravity. I'm starting to go.

Normally, the bearing 2 is
To prevent impurities from entering the bearing box 3
In many cases, a shaft sealing device 4 is attached to the shaft sealing device 4.

As shown in FIG. 3, which shows an enlarged cross-sectional structure of an example of the conventional shaft sealing device 4, a housing 5 integrally assembled with the bearing box 3 includes a rotor shaft 1.
A pair of seal rings 7 and 8 facing each other sandwiching a seal disk 6 integrally fitted to the rotor shaft 1
The seal rings 7, 8 and the housing 5 are fitted so as to be slidable in the direction parallel to the seal disk 6 (left and right direction in the figure) via O-rings 9. Seal springs 10 are interposed to bring the seal rings 7 and 8 into tight sliding contact, and care is taken to prevent impurities (not shown) from flowing into the bearing 2 side from the centrifuge main body side (left side in the figure). Further, an impeller 11 is fitted on the outer circumferential surface of the rotor shaft 1 inside the shaft sealing device 4, and prevents impurities from flowing into the seal disk 6 side with the side end of the housing 5. A sealing gas supply hole 12 opens in the gap A between the impeller 11 and the side end of the housing 5.
is formed in the housing 5, and seal gas from a seal gas supply source (not shown) is supplied to the seal gas supply hole 1.
It is designed to be fed into the gap A from 2.

<Problems to be solved by the invention> When centrifuging a liquid in which fine powder is dispersed,
In the conventional shaft sealing device shown in FIGS. 2 and 3,
It is virtually impossible to prevent the fine powder from flowing into the gap A only by generating airflow due to the rotation of the impeller 11. Therefore, a large amount of seal gas must be force-fed from the seal gas supply hole 12 to the gap A. The reality is that

However, when a centrifuge is in operation, the conditions for centrifugation are not uniform, and the amount of seal gas supplied changes due to fluctuations in various external or internal conditions, causing impurities to leak into the inner seal ring. 7 and the seal disk 6. As a result, the function of the shaft sealing device deteriorates, and repair work such as disassembly and maintenance must be frequently performed, resulting in problems such as a decrease in operating efficiency.

In view of the above-mentioned problems in the conventional shaft sealing devices, the present invention aims to provide a high-performance shaft sealing device that does not impair the function of the shaft sealing device itself even if the number of repair operations is reduced. do.

<Means for Solving the Problems> The shaft seal device according to the present invention includes a seal disc that is integrally attached to the rotor shaft, and a cylindrical housing that is integrally provided with the bearing box so as to surround the seal disc. , the seal disks are tightly fitted into the housing so as to be slidable in a direction parallel to the rotor axis, and are opposed to each other with the seal disk sandwiched therebetween, and are biased in the opposing direction by a spring force. A shaft sealing device comprising: a pair of seal rings in sliding contact with respective end faces of the rotor shaft; , a plurality of sets of auxiliary seal rings each consisting of a garter spring fitted into these segments to gather the segments together in an annular shape and slidably press the outer peripheral surface of the rotor shaft are arranged in a direction parallel to the rotor shaft; The present invention is characterized in that these auxiliary seal rings are tightly pressed against the side end surfaces of the housing via spring force, while sealing gas is supplied to the auxiliary seal rings.

<Function> The auxiliary seal ring is pressed against the outer circumferential surface of the rotor shaft by the garter spring, sealing the gap between them, while the auxiliary seal ring and the housing are in close contact with each other due to the spring force, and the gap between them is sealed. is sealed.

The seal ring is tightly pressed against the end face of the seal disc to perform the original sealing function of the shaft sealing device, but this function is guaranteed by the sealing ability of the auxiliary seal ring.

On the other hand, sealing gas is supplied to the auxiliary seal ring side, and together with the presence of the auxiliary seal ring, impurities are prevented from entering from the sealed side.

<Embodiment> As shown in FIG. 1, which shows a cross-sectional structure of an embodiment of a shaft seal device according to the present invention, an outer housing 21 is integrally connected to a side end of a bearing box (not shown).
A cylindrical inner housing 24 that surrounds a seal disk 23 that is integrally fitted onto the outer peripheral surface of the rotor shaft 22 is concentrically connected to the rotor shaft 22 . Seal ring holders 26 and 27 are fitted into the outer housing 21 and the inner housing 24 through O-rings 25, respectively, so that they can tightly slide in a direction parallel to the rotor shaft 22 (in the left-right direction in the figure). The seal ring holders 26 and 27 have a seal ring 2 formed of carbon or the like that faces the seal disk 23 between them.
8 and 29 are integrally fitted. Then, the outer housing 21 and the inner housing 2
4 and the seal ring holders 26, 27,
Seal springs 30 are interposed to press the seal rings 28 and 29 in opposing directions.

Therefore, the spring force of these seal springs 30 causes the seal rings 28 and 29 to tightly press against both end surfaces of the seal disk 23, and the sliding movement of the seal disk 23 against the seal rings 28 and 29 causes the seal rings 28 and 29 to be pushed toward the bearing side (not shown). It has come to exhibit a shaft sealing effect. In this embodiment, in order to cool and lubricate the sliding contact portion between the seal disk 23 and the seal rings 28, 29 as the rotor shaft 22 rotates, the outer housing 21, the inner housing 24, and the seal ring holders 26, 27 Seal chamber 31 surrounded by seal rings 28 and 29
A lubricant coolant passage 32 is formed in the outer housing 21 and the inner housing 24 to communicate with the seal chamber 31 , and a lubricant coolant such as oil or hexane is supplied from a lubricant coolant supply source (not shown) connected to the lubricant coolant passage 32 to the seal chamber 31 . I'm trying to circulate it.

On the other hand, on the inner end surface of the inner housing 24,
An annular cover ring 33 is fixed by bolts 35 through a gasket 34, and a plurality of sets (two sets in this embodiment) of auxiliary seals are provided between the cover ring 33 and the side end surface of the inner housing 24. A ring 36 is arranged in a direction parallel to the rotor axis 22. The auxiliary seal ring 36 is composed of arc-shaped segments 37 that are molded from carbon or the like and assembled into an annular shape as a whole, and a garter spring 38 that is fitted onto these segments 37 to assemble the segments 37 into an annular shape.
It surrounds the rotor shaft 22. This auxiliary seal ring 36 is tightly pressed against the outer circumferential surface of the rotor shaft 22 by the spring force of the garter spring 38 to seal the gap therebetween. Further, between the auxiliary seal ring 36 and the inner housing 24, the auxiliary seal ring 36 is pressed against the side end surface of the cover ring 33, and impurities are removed from the gap between the cover ring 33 and the auxiliary seal ring 36 toward the seal disk 23 side. An auxiliary seal spring 39 is interposed to prevent the flow from occurring. The auxiliary seal chamber 4 is surrounded by the inner housing 24, the inner seal ring holder 27, the cover ring 33, and the auxiliary seal ring 36.
0 is formed in the inner housing 24, and this seal gas supply hole 4
A seal gas supply source (not shown) is connected to 1 to force seal gas into the auxiliary seal chamber 40 . In this embodiment, in addition to this, a rotation prevention pin 42 of the auxiliary seal ring 36 is provided to protrude from the side end surface of the inner housing 24.

Therefore, impurities flow into the seal disk 23 side due to the pressure of the seal gas filling the auxiliary seal chamber 40, the seal between the auxiliary seal ring 37 and the cover ring 33, and the seal between the auxiliary seal ring 37 and the rotor shaft 22. is almost completely blocked, and the seal disc 23 and seal ring 28,2
This ability can be fully demonstrated without impairing the shaft sealing function of 9.

In this embodiment, the auxiliary seal ring 36 is pressed toward the cover ring 33, but it may be pressed toward the inner housing 24. Furthermore, it is of course possible to make the outer housing 21 and the inner housing 24 integrally, rather than separately.

<Effects of the invention> According to the shaft sealing device of the invention, since an auxiliary seal ring is provided inside the seal disk, the amount of seal gas leakage is significantly smaller than that of conventional systems.
Moreover, since it has become possible to almost completely prevent the inflow of impurities, the repair period for the shaft sealing device can be extended compared to conventional methods, and there is less risk of damage to the function of the shaft sealing device itself.

[Brief explanation of drawings]

Fig. 1 is a cutaway view showing the internal structure of a part of an embodiment of the shaft sealing device according to the present invention, Fig. 2 is a cutaway view showing the structure of the bearing portion of the centrifuge, and Fig. 3 is a cutaway view showing the structure of the bearing portion of the centrifuge. It is a broken view showing an example of a sealing device. Also, in the figure, 21 is an outer housing, 2
2 is a rotor shaft, 23 is a seal disk, 24 is an inner housing, 25 is an O-ring, 26, 27 are seal ring holders, 28, 29 are seal rings, 30 is a seal spring, 33 is a cover ring, 34 is a packing, 35 is a bolt, 36 is an auxiliary seal ring, 37 is a segment, 38 is a garter spring, 39 is an auxiliary seal spring, 41
is the seal gas supply hole.

Claims (1)

[Scope of utility model registration request] a seal disk that is integrally attached to the rotor shaft; a cylindrical housing that is integrally provided with a bearing box to surround the seal disk; and a cylindrical housing that is slidable in a direction parallel to the rotor axis relative to the housing. A shaft sealing device comprising: a pair of seal rings that are tightly fitted and face each other with the seal disk sandwiched therebetween, and that slide into sliding contact with the end surfaces of the seal disk through spring forces biased in opposite directions. , a plurality of arc-shaped segments arranged so as to surround the outer peripheral surface of the rotor shaft inside the seal disk;
A plurality of auxiliary seal rings each consisting of a garter spring that is fitted into these segments to gather the segments together in an annular shape and slidably press the outer circumferential surface of the rotor shaft are arranged in a direction parallel to the rotor shaft. A shaft sealing device characterized in that an auxiliary seal ring is tightly pressed against a side end surface of the housing via a spring force, and a sealing gas is supplied to the auxiliary seal ring side.