JP2009062965A - Centrifugal compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To uniformize meshing of a ring gear and a vane gear of an inlet guide vane in a circumferential direction of a rotor; and to reduce sliding resistance. <P>SOLUTION: A roller 21 is attached to a vane shaft 11b together with the vane gear 12 in parallel to the vane gear 12 attached to the vane shaft 11b of the inlet guide vane 11a. Further, an outside diameter of the roller 21 is set to be identical with a diameter of a pitch circle of the inlet guide vane 11a. Furthermore, a ring member 22 having an inside diameter identical with the diameter of the pitch circle of the vane gear 12 of the inlet guide vane 11a is provided on a side surface of the ring gear 13, and the roller 21 and the ring member 22 are abutted with each other so as to be rotatable. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a centrifugal compressor, and more particularly to a centrifugal compressor suitable for use in applications where the handling flow rate (suction flow rate) for handling various gases including hydrocarbon gas and carbon dioxide gas varies.

  Conventionally, there is a centrifugal compressor having a barrel-type casing as disclosed in Patent Document 1 as a centrifugal compressor in such a field. Moreover, what is described in patent document 2, a nonpatent literature 1, etc. is known as a capacity | capacitance adjustment apparatus attached to such a centrifugal compressor.

  And the suction flow path is formed in the radial direction in the centrifugal compressor equipped with a plurality of impellers on one axis. In order to adjust the capacity of such a centrifugal compressor, generally, a plurality of inlet guide vanes are arranged in the circumferential direction surrounding the rotor, the gears attached to the shafts are meshed with one ring gear, and the ring gears are integrated. It is structured to rotate by a gear provided on the drive shaft of the book.

  This ring gear needs to maintain a certain degree of coaxiality accuracy with respect to the axis of the rotor in order to smoothly and evenly rotate the vane shaft of the inlet guide vane arranged in the circumferential direction of the rotor.

  Therefore, although the detailed structure is not described in Patent Documents 1 and 2 and Non-Patent Document 1, generally, it is generated between the ring gear and the vane gear by applying lubricating oil between the ring gear and the vane gear. Sliding wear is reduced, and the ring gear is rotated while maintaining coaxiality with the axis of the rotor.

Japanese Patent Laid-Open No. 55-7914 JP 2003-269394 A Product catalog of Mannesmann Demag Delaval, 1998 edition, p. 20

  In the inlet guide vane drive device provided in the radial suction passage as described above, the ring gear that rotates the plurality of inlet guide vanes needs to maintain the coaxiality with the axis of the rotor. The ring gear meshes with the vane gear of the inlet guide vane on one side (for example, the inner circumference side) and meshes with the drive gear for rotating the ring gear (for example, the outer circumference side) on one side. The ring gear is configured to float between the two gears.

  For this reason, the ring gear receives an external force from the weight of the ring gear or the drive shaft gear, and tends to decenter from the rotor shaft center. If there is no member that maintains the coaxiality, it is eccentric, and the meshing portion between the vane gear and the ring gear of the inlet guide vane becomes deep in part and shallow in the opposite direction. When the meshing becomes deeper, meshing with the pitch circle is lost, so that both tooth tips, tooth roots or tooth bottoms come into contact with each other, and smooth meshing is lost. If this happens, an abnormal force is applied, which may cause abnormal wear and damage.

  Therefore, in order to smoothly rotate the ring gear in the circumferential direction, it is necessary to keep the axis of the ring gear the same as the axis of the rotor. Therefore, conventionally, lubricating oil having a small sliding resistance has been applied between the ring gear and the vane gear. However, there is a problem that the lubricating oil may not be used due to the requirement of gas handled by the centrifugal compressor (for example, a low temperature state of −100 ° C. or lower).

  In view of this, the present invention provides a centrifugal compressor that can make the meshing between the ring gear and the vane gear of the inlet guide vane uniform in the circumferential direction of the rotor and reduce the sliding resistance and sliding wear generated between the two. The purpose is to do.

In order to solve the above-described problems, the present invention changes the inlet flow angle of an impeller attached to a rotor by an inlet guide vane device provided in a stationary flow path into which gas flows from the radial direction of the rotor. In a centrifugal compressor that adjusts the suction flow rate,
The inlet guide vane device is disposed in a circumferential direction of the rotor so as to surround the rotor in the stationary flow path, and has a plurality of inlet guide vanes having a vane shaft in parallel with the axis of each rotor. A vane gear provided on a vane shaft of each of the plurality of inlet guide vanes, a ring gear that meshes with the vane gear on an inner peripheral side, and that can rotate in the circumferential direction of the rotor about the axis of the rotor; A drive shaft gear that meshes with the ring gear and rotates the ring gear, and has the same diameter as the pitch circle of the ring gear over the entire circumference on the inner circumferential side of the ring gear. A roller rolling contact surface is provided, and a roller having the same diameter as the pitch circle of the vane gear of the inlet guide vane is provided on the vane shaft of the inlet guide vane. It is characterized in that the La and the roller rolling contact surface brought rolling contact each other.

  With this configuration, when the ring gear is rotated by the drive shaft gear, the vane gear provided on the vane shaft of the inlet guide vane that is mounted so as to mesh with the inner periphery of the ring gear rotates. The guide vane rotates.

  At this time, the outer peripheral surface of the roller attached to the vane shaft of the inlet guide vane comes into contact with the roller rolling contact surface provided on the inner peripheral side of the ring gear, and the center of rotation of the ring gear is coaxial with the axis of the rotor. It is controlled to become. Moreover, the frictional resistance between the ring gear and the vane gear can be reduced by the rolling contact between the roller and the roller rolling contact surface. Furthermore, since the roller is in rolling contact, the material of the roller can be a metal material, for example. In this way, there is no difference in the thermal expansion coefficient of the materials, which is advantageous in structural design.

  According to the present invention, since the roller rolling contact surface formed on the ring gear and the roller can be brought into rolling contact with each other, in the inlet guide vane device provided in the stationary flow path, the ring that rotates the vane shaft of the inlet guide vane Since the gear can be rotated coaxially with the axis of the rotor without sliding friction, there is no fear of wear life and a highly reliable centrifugal compressor can be provided.

  A first embodiment of a centrifugal compressor according to the present invention will be described with reference to FIGS.

  FIG. 1 is a longitudinal sectional view of the vicinity of a suction portion of a centrifugal compressor. In FIG. 1, the rotor 1 to which the impeller 2 is attached is rotated by being supported by the bearing 6 in the casing 3 and the head flange 4, thereby compressing the gas. A shaft seal device 5 is attached to the inside (machine inside) of the bearing 6. A nozzle 7 is attached to the casing 3, and the gas sucked from the nozzle 7 passes through the radial suction passage portion 8 that is a stationary passage portion and is sucked into the impeller 2. Gas compressed by a plurality of impellers is discharged from a discharge nozzle (not shown).

  The inlet guide vane device 33 includes an inlet guide vane 11a, a vane shaft 11b, a vane gear 12, a ring gear 13, a gear 14, a drive shaft 15, arms 16, 17 and the like.

  Here, the inlet guide vane 11 a is provided inside the radial suction channel portion 8. A vane shaft 11b, which is an attachment shaft, is attached to the inlet guide vane 11a. A plurality of inlet guide vanes 11 a are arranged in the circumferential direction of the rotor 1 so as to surround the rotor 1. A vane gear 12 is attached to the vane shaft 11b of the inlet guide vane 11a, and the vane shaft 11b is rotatably supported by an inlet guide bearing 18.

  On the other hand, on the radially outer side of the vane shaft 11b of the inlet guide vane 11a, a ring gear 13 having internal teeth that mesh with the vane gears 12 of all the inlet guide vanes 11a is provided, and a part of the outer peripheral surface of the ring gear 13 is provided. Has external teeth.

  Further, on the radially outer side of the ring gear 13, there is a gear 14 that meshes with the external teeth of the ring gear 13, and the gear 14 is attached to the drive shaft 15. The drive shaft 15 is attached through the head flange 4 in the axial direction of the rotor 1. In addition, arms 16 and 17 are attached to the outer end of the centrifugal compressor to form a crank mechanism. The crank mechanism is swung by an appropriate drive machine such as a servo motor. That is, when the drive shaft 15 is rotated by the crank mechanism, the drive gear 14 is rotated and the ring gear 13 is rotated, and accordingly, the vane gear 12 is rotated and the inlet guide vane 11 is rotated. .

  When the inlet guide vane 11 rotates, the gas sucked from the suction nozzle 7 has a flow component in the circumferential direction of the rotor 1 when viewed from a cross section perpendicular to the axis of the rotor 1. . That is, when the gas demand in the downstream plant of the centrifugal compressor is reduced, the flow component in the circumferential direction of the rotor 1 is changed in accordance with the decrease in the axial flow velocity at the inlet of the impeller 2, and the blades of the impeller 2 are changed. By adjusting the inlet flow angle to the blade angle, the blade inlet collision loss can be minimized. In other words, when the capacity of the centrifugal compressor changes, the suction flow rate at which the impeller generates stall can be reduced, so that the operating range to a small flow rate region can be expanded as compared with the case where there is no inlet guide vane device.

  FIG. 2 is a partially enlarged view showing the drive shaft 15, the ring gear 13, the inlet guide vane 11a and the like in FIG. A roller 21 is provided in parallel with the vane gear 12 on the vane shaft 11b of the inlet guide vane 11a. The outer diameter of the roller 21 is formed to be the same as the pitch circle diameter of the vane gear 12 of the inlet guide vane 11a. The rollers 21 may be attached to the vane shafts 11b of all the inlet guide vanes 11a. However, several rollers may be attached at equal intervals in the circumferential direction in consideration of economy.

  Here, on the ring gear 13 side, an inner peripheral surface of the ring-shaped protrusion 31 that protrudes from the radial intermediate portion of the side surface of the ring gear 13 and extends over the entire circumference in the circumferential direction of the side surface and the ring gear. The ring member 22 is fitted into a cutout portion 32 having a substantially L-shaped cross section formed between the side surfaces of 13. The ring member 22 is formed as an annular body having a substantially rectangular cross section having the same pitch circle diameter and inner diameter as the ring gear 13 meshing with the vane gear 12 of the inlet guide vane 11a. The inner peripheral surface of the ring member 22 is a rolling contact surface 22a with which the roller 21 is in rolling contact.

  The ring member 22 may be integrated with the ring-shaped protrusion 31 of the ring gear 13. However, considering the ease of processing the internal teeth of the ring gear 13, it is more convenient to use a separate member.

  FIG. 3 is a view of the centrifugal compressor of the present embodiment as viewed from the direction perpendicular to the rotor shaft. A drive shaft 15 is disposed outside the ring gear 13, and a meshing portion 19 is formed between the gear 14 of the drive shaft 15 and the external teeth of the ring gear 13. The drive shaft 15 is rotated by a link mechanism including arms 16 and 17.

  Further, FIG. 4 shows the meshing portion 19 of the ring gear 13 and the vane gear 12 according to the present invention, and the contact portion between the surface of the ring gear 13 whose inner circumference is an inner pitch circle and the roller 21 described above at right angles to the axis of the rotor 1. Seen from the direction.

  When the ring gear 13 is rotated by the gear 14 of the drive shaft 15, the vane gear 12 of the inlet guide vane 11a mounted so as to mesh with the inner periphery of the ring gear 13 is rotated as shown in FIG. The guide vane 11a rotates. At this time, on the other hand, the outer peripheral surface of the roller 21 attached to the vane shaft 11b of the inlet guide vane 11 together with the vane gear 12 of the inlet guide vane 11a by the key 37 and the inner peripheral surface of the ring member 22 on the ring gear 13 side. And the center of rotation of the ring gear 13 is adjusted to be coaxial with the axis of the rotor 1.

  With this configuration, when the ring gear 13 is rotated by the gear 14 of the drive shaft 15, the vane gear 12 of the inlet guide vane 11a mounted so as to mesh with the inner periphery of the ring gear 13 rotates. At the same time, the roller rolling contact surface 22a, which is the inner peripheral surface of the ring member 22 attached to the outer peripheral ring gear 13 of the roller 21 attached to the vane shaft 11b, comes into contact, and the center of the ring gear 13 is coaxial with the axis of the rotor 1 It rotates while maintaining the degree. Since the contact surface between the outer peripheral surface of the roller 21 and the ring member 22 at this time is the same as the meshing pitch circle between the vane gear 12 and the ring gear 13 of the inlet guide vane 11a, rolling contact is established.

  Accordingly, since the rolling contact can be achieved in this way, the frictional resistance between the vane gear 12 and the ring gear 13 can be reduced, and the sliding friction is not accompanied, so that wear can be prevented. Furthermore, since it is rolling contact, the material of the roller 21 can also use a metal material, for example. In this way, there is no difference in the thermal expansion coefficient of the materials, which is advantageous in structural design.

  Moreover, in this embodiment, even when the centrifugal compressor is used in a harsh environment of at least −100 ° C. or less at atmospheric pressure, the roller 21 and the ring member 22 are brought into rolling contact with each other, and the vane gear 12 and the ring gear 13 are brought into contact with each other. Since sliding friction can be eliminated, it is possible to eliminate the problem that the lubricating oil freezes when the lubricating oil is applied to the meshing portion of the vane gear 12 and the ring gear 13.

  Next, FIG. 5 and FIG. 6 show a second embodiment of the present invention. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

  5 and 6 show only the structure near the meshing portion between the ring gear 23 and the vane gear 12 of the inlet guide vane 11a. In the present embodiment, as shown in FIG. 5, the internal teeth of the ring gear 23 are integrated (the ring gear 23 is divided into two parts and integrated with the flange surfaces thereof being integrated as an integral part). The ring gear 23 is cut out.

  Further, a ring-shaped protrusion 40 is formed on the side surface of the ring gear 23, and its inner peripheral side is a roller rolling contact surface 40a. Then, the ring-shaped protrusion 40 is processed so as to be a cylindrical surface having an engagement pitch circle between the vane gear 12 and the ring gear 13 as an inner periphery so that the roller 21 and the ring-shaped protrusion 40 are in rolling contact with each other. It is.

6, as in FIG. 4, the meshing portion of the ring gear 23 and the vane gear 12 of the inlet guide vane 11 a and the contact portion between the roller 21 and the surface having the inner circumference of the pitch circle of the inner teeth of the ring gear 23 are shown. Viewed from the direction perpendicular to the rotor shaft.
The inner peripheral surface of the ring gear 23 to which the roller 21 attached to the vane shaft 11b of the inlet guide vane 11a is in rolling contact has a bottom portion, so that there are irregularities, but there are a plurality of vane shafts 11b of the inlet guide vane 11a. By being present, the ring gear 13 can be rotated while being substantially coaxial with the axis of the rotor 1.

  In addition, after gear-cutting the vane gear 12 of the inlet guide vane 11a, a part in the width direction is processed into a cylindrical surface having a pitch circle as an outer periphery, while the ring gear 13 has an inner tooth pitch circle as an inner periphery. A member (ring member 22 in FIG. 2) may be attached and both may be in rolling contact.

It is a longitudinal section showing a centrifugal compressor by a 1st embodiment of the present invention. It is the elements on larger scale which show the drive shaft, ring gear, inlet guide vane, etc. in FIG. It is the front view which looked at the centrifugal compressor in FIG. 1 from the orthogonal | vertical direction of the rotor axis | shaft. It is the elements on larger scale which show the ring gear, inlet guide vane, roller, etc. in FIG. It is the elements on larger scale which show the drive shaft, ring gear, inlet guide vane, etc. of the centrifugal compressor by the 2nd Embodiment of this invention. It is the elements on larger scale which show the ring gear, inlet guide vane, roller, etc. of the centrifugal compressor by the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rotor, 2 ... Impeller, 3 ... Casing, 4 ... Head flange, 5 ... Shaft seal device, 6 ... Bearing, 7 ... Suction nozzle, 8 ... Radial suction passage, 11a ... Inlet guide vane, 11b ... Vane shaft , 12 ... vane gear, 13 ... ring gear, 14 ... gear, 15 ... drive shaft, 16, 17 ... arm, 18 ... inlet guide bearing, 19 ... meshing part, 21 ... roller, 22 ... ring member, 23 ... ring gear, DESCRIPTION OF SYMBOLS 31 ... Ring-shaped projection part, 32 ... L-shaped notch part, 33 ... Inlet guide vane apparatus, 37 ... Key, 40 ... Ring-shaped projection part, 40a ... Roller rolling contact surface.

Claims (3)

In the centrifugal compressor that adjusts the suction flow rate by changing the inlet flow angle of the impeller attached to the rotor by an inlet guide vane device provided in a stationary flow path into which gas flows from the radial direction of the rotor,
The inlet guide vane device is
A plurality of inlet guide vanes disposed in a circumferential direction of the rotor so as to surround the rotor in the stationary flow path and having a vane shaft in parallel with the axis of each rotor;
A vane gear provided on a vane shaft of each of the plurality of inlet guide vanes;
A ring gear that meshes with the vane gear on the inner peripheral side and that can rotate in the circumferential direction of the rotor around the axis of the rotor;
A drive shaft gear meshing with the ring gear and rotating the ring gear;
With
On the inner peripheral side of the ring gear, a roller rolling contact surface having the same diameter as the pitch circle of the ring gear is provided over the entire circumference in the circumferential direction.
The vane shaft of the inlet guide vane is provided with a roller having the same diameter as the pitch circle of the vane gear of the inlet guide vane,
A centrifugal compressor, wherein the roller and the roller rolling contact surface are in rolling contact with each other.   A ring-shaped projection extending over the entire circumference in the circumferential direction of the side surface is provided on a side surface of the ring gear, and a ring member is fitted and attached between the ring-shaped projection and the side surface. 2. The centrifugal compressor according to claim 1, wherein an inner peripheral surface of the member is the roller rolling contact surface.   The centrifugal compressor according to claim 1 or 2, wherein the use environment is used at a low temperature of at least -100 ° C or less under atmospheric pressure.

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