JP2004197848A - Shaft seal device and turbo compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shaft seal device being easily machined and easily fixed to a supporting member, and to provide a turbo compressor being easily fixed to a casing by comprising the shaft seal device. <P>SOLUTION: In this shaft seal device wherein a bearing 12 is supported by the supporting member (casing) 14, and a shaft seal part is constituted by a supporting part of the supporting member 14, the shaft seal part is composed of a gas seal labyrinth 11 mounted at a gas atmosphere side and preventing the gas leakage, and an oil seal labyrinth 13 mounted at an oil atmosphere side and preventing the oil leakage, and an outer diameter of the gas seal labyrinth 11 and an outer diameter of the oil seal labyrinth 13 are approximately same as each other. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a shaft sealing device and a turbo compressor provided with the shaft sealing device.
[0002]
[Prior art]
A turbo compressor including a centrifugal impeller, a mixed flow impeller, or an axial impeller is a rotary fluid machine that increases the pressure of a target gas by suctioning the target gas by rotating the impeller. Turbocompressors must support a rotating part or rotating shaft with a non-rotating part or casing. In order for the rotating shaft to operate, it is necessary to have an appropriate gap with the casing.However, in a turbo compressor, a ring-shaped gas seal labyrinth is attached to the rotating shaft because the target gas with increased pressure leaks from the gap. Leaks are minimized.
[0003]
Further, lubricating oil is applied between the supporting portion such as a bearing and the driving portion in order to prevent friction and wear, but it is desirable that the lubricating oil does not leak to the target gas. In order to prevent the leakage of the lubricating oil, it is effective to mount a ring-shaped oil seal labyrinth on the rotating shaft. By arranging the oil seal labyrinth on the bearing side (oil atmosphere side) and the gas seal labyrinth on the impeller side (gas atmosphere side), it is possible to effectively prevent the leakage of the lubricating oil and the target gas.
[0004]
Furthermore, in order to smoothly rotate the rotating shaft while preventing leakage of the lubricating oil and the target gas, strict processing accuracy is required for the inner and outer diameters of each labyrinth, the inner diameter of the casing, and the outer diameter of the rotating shaft. A gap is required inside each labyrinth so as not to contact the rotating shaft, and a small gap is better outside each labyrinth to prevent leakage. It is also important that the outer diameter of the rotating shaft, the outer diameter of each labyrinth, and the inner diameter of the casing are concentric.
[0005]
In the conventional technology, as a shaft sealing device for fixing the oil seal labyrinth and the gas seal labyrinth to the casing, a structure in which the oil seal labyrinth or the gas seal labyrinth is directly fixed to the casing with bolts or the like, and the casing corresponds to each seal labyrinth. There is known a structure in which a sealing inlay is provided to restrict the axial movement of the seal labyrinth (for example, Patent Document 1).
[0006]
[Patent Document 1]
JP-A-9-280383
[Problems to be solved by the invention]
In the above prior art, in order to fix the seal labyrinth, it is directly fixed to the casing with bolts or the like, or the outer diameters of the oil seal labyrinth and the gas seal labyrinth are changed, and each labyrinth is restrained in the axial direction by the spigot portion of the casing. Structure is adopted. However, in such a structure, the number of assembling steps is increased, and a high processing accuracy is required for the casing.
[0008]
An object of the present invention is to provide a shaft sealing device which is easy to process and can be easily fixed and assembled to a support member such as a casing.
Another object of the present invention is to provide a turbocompressor which is easy to fix and assemble to a casing by including the shaft sealing device.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a shaft sealing device according to the present invention is a shaft sealing device in which a bearing is supported by a support member and a shaft seal portion is configured by a support portion of the support member, wherein the shaft seal portion includes: A gas seal labyrinth arranged on the gas atmosphere side to prevent gas leakage and an oil seal labyrinth arranged on the oil atmosphere side to prevent oil leakage, the outer diameter of the gas seal labyrinth and the outside of the oil seal labyrinth The diameters are substantially the same.
More specifically, an annular projection is formed on the outer peripheral surface of the oil seal labyrinth, an annular groove is formed on the inner peripheral surface of the hole of the support member that supports the oil seal labyrinth, and the annular projection fits into the annular groove. The oil seal labyrinth is supported by the support member.
[0010]
Further, the gas seal labyrinth and the oil seal labyrinth are divided into two, an annular groove is formed on the outer peripheral surface of one of the gas seal labyrinth and the oil seal labyrinth, and the other face facing the gas seal labyrinth or the oil seal labyrinth An annular projection is formed on the outer peripheral surface of the oil seal labyrinth or gas seal labyrinth, and the annular projection is fitted into the annular groove so that the two are joined. The gas seal labyrinth, the oil seal labyrinth, and the bearing have substantially the same outer diameter.
[0011]
In order to achieve the above object, a turbo compressor including a shaft sealing device according to the present invention includes an impeller, a rotating shaft that rotationally drives the impeller, a bearing that supports the rotating shaft, and a bearing that supports the bearing. In a turbo compressor provided with a shaft sealing device in a casing, the shaft sealing device includes a gas seal labyrinth disposed on an impeller side to prevent gas leakage, and an oil seal labyrinth disposed on a bearing side to prevent oil leakage. And the outer diameter of the gas seal labyrinth and the outer diameter of the oil seal labyrinth are substantially the same.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing an example of a turbo compressor provided with a centrifugal impeller.
[0013]
First, a schematic structure of the turbo compressor will be described.
The turbo compressor is arranged such that a casing 1, a shroud 2 for forming a spiral flow path in the casing 1, a suction port side is located at the center of the shroud 2, and a discharge port side is located in the shroud 2. The centrifugal impeller 3 is fixed to the casing 1 with bolts 5, and includes a lid 6 that forms a suction flow path 4 by sealing the casing 1.
[0014]
In the above configuration, when the centrifugal impeller 3 is rotated by a rotation drive source (not shown), gas is sucked from the suction port side. The sucked gas is compressed by the centrifugal impeller 3 and flows into the helical flow path. The gas is pressurized to a predetermined pressure while rotating in the helical flow path. Is sucked into the next stage compressor.
[0015]
The rotating shaft 7 that rotationally drives the centrifugal impeller 3 is rotationally driven by a torque transmitted from a rotational driving source via a gear 8 and a pinion 9 that meshes with the gear 8. The impeller 3 and the thrust collars 10A and 10B are integrally formed with the rotary shaft 7 by a key or shrink fitting. The torque transmitted to the rotating shaft 7 is transmitted to the impeller 3, and the rotation of the impeller 3 compresses the target gas. When compressing the target gas, a pressure difference is generated between the suction port side and the discharge port side of the impeller 3, and the pressure difference is a main cause, and a thrust force is generated on the rotating shaft 7 to the left. The thrust force is received by 10B of the thrust collars 10A and 10B. More specifically, the thrust collars 10A and 10B have a structure in which the thrust force in the left-right direction is received by contacting the left and right side ends of the gear 8. The gear 8 is supported by a bearing (not shown) that receives both the radial force and the thrust force.
[0016]
Next, the shaft sealing portion will be described.
A gas seal labyrinth 6 is inserted into the casing 1 at the rear portion of the impeller 3 into a hole penetrating the casing 1, and the compressed gas flows from between the rotating shaft 7 and the labyrinth 11 </ b> B (see FIG. 2) to the bearing side. (Oil side). Further, lubricating oil is injected to the pinion 9 and the bearing 12 (in the embodiment, a sliding bearing) by a method (not shown) in order to smooth the rotation. An oil seal labyrinth 13 is provided to prevent the lubricating oil from leaking from between the rotating shaft 7 and the labyrinth 13B (see FIG. 2) to the impeller 3 side (gas atmosphere side). The oil seal labyrinth 13 is disposed between the gas seal labyrinth 11 and the bearing 12. The gas seal labyrinth 11 and the oil seal labyrinth 13 are combined by a method described later to form a shaft sealing portion.
[0017]
FIG. 2 is a perspective view of the gas seal labyrinth 11 and the oil seal labyrinth 13 constituting the shaft sealing portion.
The gas seal labyrinth 11 is divided into two parts, an annular groove 11A having an L-shaped cross section is formed on the outer peripheral surface, and a gap between the rotary shaft 7 is appropriately maintained on the inner peripheral surface of the hole, and gas leakage occurs. The labyrinth 11B is formed so as to prevent the occurrence of the labyrinth. Similarly, the oil seal labyrinth 13 is also divided into two parts, and an annular projection 13A having an L-shaped cross section is also formed on the outer peripheral surface facing the gas seal labyrinth 11, so that the annular projection 11A fits into the annular groove 11A. I have. In addition, a labyrinth 13B is formed on the inner peripheral surface of the hole of the oil seal labyrinth 13 so as to appropriately maintain a gap between the oil seal labyrinth 13 and the rotating shaft 7 and prevent oil leakage.
[0018]
Further, on the outer peripheral surface of the oil seal labyrinth 13, an annular projection 13C is formed. The annular projection 13C fits into an annular groove 14B (see FIG. 1 and FIG. 3 described later) formed on the inner peripheral surface of the hole of the casing 14 (support member), and the oil seal labyrinth 13 is fixed to the casing 14. , To be supported.
[0019]
FIG. 3 is an exploded view showing only a part of the turbo compressor. This embodiment is an example of a multi-stage turbo compressor in which a plurality of compressors (one in the figure) are arranged and pressure is gradually increased. It is.
An annular groove 14B is formed on the inner peripheral surface of the shaft sealing portion of the casing 14 so as to fit with the annular projection 13C of the oil seal labyrinth 13. In the box of the casing 14, a gear chamber 14C in which the gear 8, the pinion 9, and the like are stored is formed.
[0020]
In the above configuration, an example of how to assemble the turbo compressor will be described (however, the invention is not limited to this example).
(1) A casing 14 is prepared in which the hole diameter of the portion where the gas seal labyrinth 11 and the oil seal labyrinth 13 are arranged is processed to be the same or substantially the same. An annular groove 14B is further formed in the portion where the oil seal labyrinth 13 is disposed, and the hole diameter of the portion where the bearing 12 is disposed is also processed to be the same or substantially the same as the hole diameter. Since the casing 14 has a two-part structure, upper and lower members are prepared. Further, the casing 1 is already attached to a lower member of the casing 14.
(2) The rotating shaft 7 (the state in which the impeller 3, the thrust collars 10A and 10B, and the pinion 9 are already mounted) is installed on the lower member of the casing 14 (however, in the case of a rotating shaft requiring an impeller at both ends). , One of the impellers will be attached in a later step).
(3) A half-split (lower member) of the bearing 17 is installed while supporting the rotating shaft 7. After that, the one half of the bearing 12 (upper member) is installed.
(4) The lower member of the gas seal labyrinth 11 is installed at a predetermined position, and the annular projection 13A and the annular projection 13C of the lower member of the oil seal labyrinth 13 are aligned with the annular groove 11A of the gas seal labyrinth 11 and the annular groove of the casing 14. The lower member of the oil seal labyrinth 13 is installed so as to fit with 14B.
(5) Similarly, the upper members of the gas seal labyrinth 11 and the oil seal labyrinth 13 are installed.
(6) If impellers are attached to both ends of the rotating shaft, attach the remaining impellers.
(7) The gear 8 and other members of the rotation drive source are attached to the casing 14.
(8) The shroud 2 and the lid 6 are attached.
(9) The upper member of the casing 14 is attached to the lower member.
[0021]
As described above, when the gas seal labyrinth 11 and the oil seal labyrinth 13 are fixed to the casing 14, and when the gas seal labyrinth 11 is fixed to the oil seal labyrinth 13, it is necessary to use a fixing tool such as a bolt. There is no. For this reason, a shaft sealing device in which the gas seal labyrinth 11 and the oil seal labyrinth 13 can be easily fixed to the casing 14 (support member) is obtained. Further, since the hole diameter of the shaft sealing portion of the casing 14 is the same or substantially the same, the number of processing steps is reduced, and the processing is facilitated.
Therefore, the turbo compressor including the shaft sealing device can be easily fixed to the casing 14.
In addition, although processing of the annular groove 14B is also required, high precision is not required as much as processing precision required for each labyrinth seal outer diameter and casing hole diameter. Therefore, the number of processing steps of the casing 14 is reduced.
[0022]
【The invention's effect】
As described above, according to the present invention, it is possible to obtain a shaft sealing device that can be easily processed and that can easily position the seal labyrinth and fix the seal labyrinth to the support member.
Further, according to the present invention, it is possible to obtain a turbo compressor that is easily fixed to a casing or the like by including the shaft sealing device.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a turbo compressor having a centrifugal impeller.
FIG. 2 is a perspective view of a gas seal labyrinth and an oil seal labyrinth constituting a shaft sealing portion.
FIG. 3 is an exploded view of the turbo compressor, showing only some elements.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Casing, 2 ... Shroud, 3 ... Impeller, 4 ... Suction channel, 5 ... Bolt, 6 ... Lid, 7 ... Rotating shaft, Pinion, 8 ... Gear, 9 ... Pinion, 10A, 10B ... Thrust collar, 11 ... gas seal labyrinth, 11A ... annular groove, 12 ... bearing, 13 ... oil seal labyrinth, 13A ... annular projection, 13B ... labyrinth, 13C ... annular projection, 14 ... casing (supporting member), 14B ... groove, 14C ... gear chamber .

Claims (5)

In a shaft sealing device in which a bearing is supported by a support member and a shaft seal portion is configured by a support portion of the support member,
The shaft sealing portion includes a gas seal labyrinth disposed on the gas atmosphere side to prevent gas leakage, and an oil seal labyrinth disposed on the oil atmosphere side to prevent oil leakage.
A shaft sealing device, wherein an outer diameter of the gas seal labyrinth and an outer diameter of the oil seal labyrinth are substantially the same. An annular projection is formed on an outer peripheral surface of the oil seal labyrinth, an annular groove is formed on an inner peripheral surface of a hole of a support member that supports the oil seal labyrinth, and the annular projection is fitted into the annular groove to form an oil seal labyrinth. The shaft sealing device according to claim 1, wherein the shaft is supported by a support member. The gas seal labyrinth and the oil seal labyrinth are divided into two, an annular groove is formed on the outer peripheral surface of one of the gas seal labyrinth and the oil seal labyrinth, and the other oil facing the gas seal labyrinth or the oil seal labyrinth 2. The shaft sealing device according to claim 1, wherein an annular projection is formed on an outer peripheral surface of the seal labyrinth or the gas seal labyrinth, and the annular projection is fitted into the annular groove so as to be connected to each other. The shaft sealing device according to claim 1, wherein outer diameters of the gas seal labyrinth, the oil seal labyrinth, and the bearing are substantially the same. An impeller, a rotating shaft that rotationally drives the impeller, a bearing that supports the rotating shaft, and a turbo compressor that includes a shaft sealing device in a casing that supports the bearing.
The shaft seal device includes a gas seal labyrinth disposed on the impeller side to prevent gas leakage and an oil seal labyrinth disposed on the bearing side to prevent oil leakage. A turbo compressor characterized in that a diameter and an outer diameter of an oil seal labyrinth are substantially the same.

Images