JP3894115B2 - Turbo compressor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a turbo compressor comprising a shaft sealing device.
[0002]
[Prior art]
A turbo compressor provided with a centrifugal impeller, a mixed flow impeller, or an axial flow impeller is a rotating fluid machine that increases the pressure of a target gas higher than that of a suction gas by rotating the impeller. A turbo compressor must support a rotating part or rotating shaft with a non-rotating part or casing. In order for the rotary shaft to operate, it is necessary to have an appropriate gap with the casing. However, in a turbo compressor, the target gas with increased pressure leaks from the gap, so a ring-shaped gas seal labyrinth is attached to the rotary shaft. Minimizes leakage.
[0003]
In order to prevent friction and wear, lubricating oil is applied between the support portion such as the bearing and the driving portion, but it is desirable that the lubricating oil does not leak into the target gas. In order to prevent the leakage of the lubricating oil, it is effective to attach a ring-shaped oil seal labyrinth to the rotating shaft. By disposing the oil seal labyrinth on the bearing side (oil atmosphere side) and the gas seal labyrinth on the impeller side (gas atmosphere side), leakage of the lubricating oil and the target gas can be effectively prevented.
[0004]
Furthermore, in order to smoothly rotate the rotating shaft while preventing leakage between the lubricating oil and the target gas, strict machining accuracy is required for the inner and outer diameters, casing inner diameter, and rotating shaft outer diameter of each labyrinth. A gap is required on the inside of each labyrinth so as not to contact the rotating shaft, and it is preferable that the outside of each labyrinth has a small gap to prevent leakage. It is also important that the rotating shaft outer diameter, each labyrinth outer diameter, and the casing inner diameter are concentric.
[0005]
In the conventional technology, as a shaft seal device that fixes the oil seal labyrinth and gas seal labyrinth to the casing, the oil seal labyrinth or gas seal labyrinth is directly fixed to the casing with bolts, etc., and each seal labyrinth is compatible with the casing There is known a structure in which an inlay is provided to restrain the axial movement of the seal labyrinth (for example, Patent Document 1).
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 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 a bolt or the like, or the outer diameter of the oil seal labyrinth and the gas seal labyrinth is changed, and each labyrinth is restrained in the axial direction by the inlay portion of the casing. The structure is adopted. However, with such a structure, the number of assembly steps increases, and high processing accuracy is required for the casing.
[0008]
An object of the present invention is that the assembly of the shaft sealing device provides easy turbocompressor.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, a turbo compressor including a shaft seal device according to the present invention includes an impeller, a suction casing, a rotating shaft that rotationally drives the impeller , a bearing that supports the rotating shaft, a bearing casing supporting the bearing, in the turbo compressor and a shaft seal device for shaft sealing between the impeller and the bearing, small-diameter hole than the outer diameter of the impeller the suction casing to the bottom form The rotating shaft has a bottomed cylindrical shape that is seamless in the circumferential direction, and one end of the rotating shaft is attached to the impeller, and a hole in the bottom of the suction casing is inserted from the impeller. The bearing casing extends into the bearing casing and is supported by the bearing. The bearing casing is divided into two parts: a lower member to which the suction casing is attached and an upper member to be attached to the lower member. Is formed with an annular groove on the inner peripheral surface of said lower member and said upper member, the shaft sealing device includes a gas seal labyrinth to prevent leakage of gas is arranged on the impeller side, disposed on the bearing side And an oil seal labyrinth that prevents oil leakage. The gas seal labyrinth is housed in a hole in the bottom of the suction casing and divided into a lower member and an upper member. An annular groove is formed on a side surface of the upper member, the oil seal labyrinth is divided into a lower member and an upper member, and an annular protrusion formed on the outer peripheral surface of the lower member and the upper member is the bearing. An annular projection formed on a side surface of the lower member and the upper member is fitted into the annular groove of the lower member and the upper member of the casing from the circumferential direction and supported by the bearing casing. Serial fitted respectively from the circumferential annular groove of the gas seal labyrinth of the lower member and the upper member is in fact where the structure is bonded to said gas seal labyrinth.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an example of a turbo compressor provided with a centrifugal impeller, and is a longitudinal sectional view thereof.
[0013]
First, the 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 positioned at the center of the shroud 2, and a discharge port side is positioned in the shroud 2. centrifugal impeller 3, wherein is thus fixed to the bolt casing 1, and a cover 6 which forms a suction passage 4 to seal the casing 1.
[0014]
In the above configuration, when the centrifugal impeller 3 is rotated by a rotational 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 spiral flow path, and the pressure is increased to a predetermined pressure while swirling the spiral flow path. For example, in the case of a multistage turbo compressor Is sucked into the compressor of the next stage.
[0015]
A rotary shaft 7 that rotationally drives the centrifugal impeller 3 is rotationally driven via a gear 8 and a pinion 9 that meshes with the gear 8 by torque transmitted from a rotational drive source. The impeller 3 and the thrust collars 1 6 A and 1 6 B are integrated 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 target gas is compressed by the rotation of the impeller 3. When the target gas is compressed, a pressure difference is generated between the suction port side and the discharge port side of the impeller 3, and the thrust force is generated in the left direction on the rotary shaft 7 mainly due to the pressure difference. The thrust force is received by 1 6 B out of the thrust collars 1 6 A and 1 6 B. More specifically, the thrust collars 1 6 A and 1 6 B have a structure in which the thrust force in the left-right direction is received by contacting the end portions on the left and right side surfaces 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 seal will be described.
The casing 1 of the rear portion of the impeller 3, a gas seal labyrinth 11 is inserted into the hole penetrating the casing 1, the bearing-side compression gas from between the rotary shaft 7 and the labyrinth 11B (see FIG. 2) Prevents leakage to the (oil atmosphere 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 make the rotation smooth. 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 seal portion.
[0017]
FIG. 2 is a perspective view of the gas seal labyrinth 11 and the oil seal labyrinth 13 constituting the shaft seal 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 thereof, and a gap between the rotary shaft 7 is properly maintained on the inner peripheral surface of the hole, and gas leakage The labyrinth 11B is formed so that it can be prevented. Similarly, the oil seal labyrinth 13 is also divided into two parts, and an annular protrusion 13A having an L-shaped cross section is formed on the outer peripheral surface facing the gas seal labyrinth 11 so as to be fitted into the annular groove 11A. Yes. A labyrinth 13B is also formed on the inner peripheral surface of the hole of the oil seal labyrinth 13 so that a gap between the rotation shaft 7 and the oil seal labyrinth 13 is properly maintained and oil leakage can be prevented.
[0018]
Furthermore, an annular protrusion 13 </ b> C is formed on the outer peripheral surface of the oil seal labyrinth 13. The annular protrusion 13 </ b> C is fitted into an annular groove 14 </ b> B (see FIG. 1, FIG. 3 described later) formed in the hole inner peripheral surface of the casing 14 (support member), and the oil seal labyrinth 13 is fixed to the casing 14. , To be supported.
[0019]
FIG. 3 shows an exploded view of 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 to gradually increase the pressure. It is.
An annular groove 14B is formed on the inner peripheral surface of the shaft seal portion of the casing 14 so as to be fitted to the annular protrusion 13C of the oil seal labyrinth 13. A gear chamber 14 </ b> C in which the gear 8, the pinion 9, and the like are accommodated is formed in the box of the casing 14.
[0020]
In the above configuration, an example of how to assemble the turbo compressor will be described (however, the present invention is not limited to this example).
(1) A casing 14 is prepared in which the hole diameters of the portions where the gas seal labyrinth 11 and the oil seal labyrinth 13 are disposed are the same or substantially the same. An annular groove 14B is further processed in the arrangement portion of the oil seal labyrinth 13, and the hole diameter of the portion where the bearing 12 is arranged is also processed to be the same as or substantially the same as the hole diameter. Since the casing 14 has a two-part structure, upper and lower members are prepared. The casing 1 is already attached to the lower member of the casing 14.
(2) The rotating shaft 7 (with the impeller 3, thrust collars 1 6 A, 1 6 B, and pinion 9 already attached) is installed on the lower member of the casing 14 (however, impellers are required at both ends) In the case of a rotating shaft, an impeller on one side is attached in a later step).
(3) while supporting the rotating shaft 7, half-split bearing 1 2 (lower member) is installed. Thereafter, a half crack (upper member) of the bearing 12 is installed.
(4) The lower member of the gas seal labyrinth 11 is installed at a predetermined position, and the annular protrusion 13A and the annular protrusion 13C of the lower member of the oil seal labyrinth 13 are 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) When impellers are attached to both ends of the rotating shaft, attach the remaining impellers.
(7) The gear 8 and other rotational drive source members 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 fixture such as a bolt. There is no. For this reason, the shaft seal 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. Moreover, since the hole diameter of the shaft seal part of the casing 14 is the same or substantially the same, the processing man-hour is reduced and the processing becomes easy.
Therefore, the turbo compressor provided with the shaft seal device can be easily fixed to the casing 14.
In addition, although the process of the annular groove 14B is also required, the high accuracy is not required as much as the processing accuracy required for each labyrinth seal outer diameter and casing hole diameter. Therefore, the processing man-hour of the casing 14 is reduced.
[0022]
【The invention's effect】
According to the present invention, the assembly of the shaft sealing device easy turbocompressor is obtained.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a turbo compressor provided with a centrifugal impeller.
FIG. 2 is a perspective view of a gas seal labyrinth and an oil seal labyrinth constituting a shaft seal portion.
FIG. 3 is an exploded view of a turbo compressor, showing only some elements.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Casing, 2 ... Shroud, 3 ... Impeller, 4 ... Suction flow path , 6 ... Cover, 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 protrusion, 13B ... labyrinth, 13C ... annular protrusion, 14 ... casing (support member), 14B ... groove, 14C ... gear chamber.

Claims (1)

An impeller, a suction casing, a rotating shaft that rotationally drives the impeller , a bearing that supports the rotating shaft, a bearing casing that supports the bearing, and a shaft seal between the impeller and the bearing. in a turbo compressor and a shaft seal device,
The suction casing has a bottomed cylindrical shape in which a hole having a smaller diameter than the outer diameter of the impeller is formed at the bottom, and there is no seam in the circumferential direction,
The rotating shaft has one side end attached to the impeller, and extends from the impeller through the hole in the bottom of the suction casing into the bearing casing and is supported by the bearing.
The bearing casing is divided into a lower member for attaching the suction casing and an upper member attached to the lower member, and an annular groove is formed on the inner peripheral surface of the lower member and the upper member,
The shaft seal device is composed of a gas seal labyrinth arranged on the impeller side to prevent gas leakage, and an oil seal labyrinth arranged on the bearing side to prevent oil leakage,
The gas seal labyrinth is housed in a hole in the bottom of the suction casing, and is divided into a lower member and an upper member, and an annular groove is formed on a side surface of the lower member and the upper member,
The oil seal labyrinth is divided into a lower member and an upper member, and annular protrusions formed on the outer peripheral surface of the lower member and the upper member are circumferentially arranged in the annular grooves of the lower member and the upper member of the bearing casing, respectively. And the annular protrusions formed on the side surfaces of the lower member and the upper member are respectively fitted in the annular grooves of the lower member and the upper member of the gas seal labyrinth from the circumferential direction. And a turbo compressor characterized by being coupled to the gas seal labyrinth .

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