JP2002206407A - Axial flow exhaust type turbine device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an axial flow exhaust type turbine device suitable for reducing losses generated at a thrust bearing part. SOLUTION: This axial flow exhaust type turbine device (steam turbine device) 1 is provided with a turbine shaft 2 supported at a closer position to a drive side end part by a journal bearing 5, and supported by a journal bearing 4 and a thrust bearing 3 at a closer position to a counter-drive side end part, compared to the conventional devices. For the diameter of the turbine shaft 2, a part supported by the journal bearing 5 is set thicker than a part supported by the journal bearing 4, and a part supported by the thrust bearing 3 is set thinner than the part supported by the journal bearing 4. A thermal expansion base point of the turbine shaft 2 is located at the thrust bearing 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axial exhaust type turbine device having a turbine shaft provided with a thrust bearing, and relates to a structure suitable for reducing a loss generated in a thrust bearing portion.

[0002]

2. Description of the Related Art Turbine devices such as steam turbines and gas turbines are rotary mechanical devices that convert kinetic energy of a fluid such as steam or gas into useful power, and are used for large rotary load devices such as generators. It is widely used as a prime mover used for driving. This type of turbine device is roughly classified into an axial exhaust type and a downward exhaust type with respect to the exhaust direction of the exhaust gas. Downward exhaust turbines require larger bends in the exhaust direction than at axial exhaust because exhaust must be bent at a right angle during discharge, but axial exhaust turbines must change direction. Since the exhaust gas can be exhausted without exhaustion, there is an advantage that the exhaust loss is reduced as compared with the case of the downward exhaust type. Hereinafter, a conventional axial exhaust type turbine device will be described with reference to FIGS. 3 and 4 as a typical example of a steam turbine. In FIG. 3, an end portion of a rotating shaft of a rotary load device such as a generator driven by a steam turbine is indicated by a dashed line, and the same applies to FIGS. Here, FIG. 3 is a longitudinal sectional view showing a main part of a conventional axial-flow exhaust type steam turbine device, and FIG. 4 is an enlarged sectional view of a portion S in FIG.

In the conventional steam turbine device 9 shown in FIGS. 3 and 4, high-temperature and high-pressure steam 99 flowing through a steam control valve 91 flows through a stationary blade 92 and a moving blade 93. The power is generated to rotate the turbine shaft 8. In the steam turbine device 9, each of the stationary blades 92 and the moving blades 93 is formed as an annular cascade, and each set of the stationary blades 92 and the moving blades 93 arranged adjacent to each other in the flow direction of the steam 99. One wing stage is provided, and a total of 27 wing stages are provided.
As is apparent from FIG. 3, the turbine shaft 8 is a columnar shaft having a large number of stepped portions and tapered portions. Coupling (load connection part) 81 for connection
A disc-shaped ballast piston 84, disc-shaped thrust collars 85, 85 and the like are integrally formed.

The coupling 81 is connected to the steam 9 of the turbine shaft 8.
The ballast piston 84 is formed at the end (drive side end) opposite to the side from which the exhaust 98 is discharged, and the ballast piston 84 is located closer to the coupling 81 than the bucket 93 located at the inflow end of the steam 99. And is formed at a portion covered by the casing 7. Further, the thrust collars 85, 85 are formed so that the side surfaces thereof face the thrust bearing portion of the composite bearing 86 so as to sandwich the composite bearing 86 from both sides, and transmit the thrust force from the side surface portions to the thrust bearing portion. In the steam turbine device 9, in addition to the impact force of the steam 99 expanded by the stationary blade 92 and having a high speed, the reaction force generated by expanding and accelerating the steam 99 in the moving blade 93 is also used to generate power. It has occurred. The ballast piston 84 offsets this reaction,
It is provided to reduce the thrust force acting on the turbine shaft 8 in the axial direction thereof.

The space where the end face of the ballast piston 84 on the rotor blade 93 side is set as a high-pressure part, and the space where the end face of the ballast piston 84 on the coupling 81 side is set as a low-pressure part, cancels out the reaction force. A force is generated on the ballast piston 84. The coupling 81 connects the rotary shaft 69 of the rotary load device to the turbine shaft 8.
In this case, the low-speed rotating device 82 is interposed between the two to be connected. The low-speed rotating device 82 is a disk-shaped device used to temporarily rotate the steam turbine device 9 at a low speed when the steam turbine device 9 is stopped, and has a gear formed on an outer peripheral portion. Further, the turbine shaft 8 is supported by a composite bearing 86 in the vicinity of the end (drive end) where the coupling 81 is formed, and the end on the exhaust discharge side (exhaust discharge end, The vicinity of one end in this case) is supported by a journal bearing 4.

In the composite bearing 86, a journal bearing portion and a thrust bearing portion formed at a portion facing the side surface of each thrust collar 85 are formed as an integral structure. The thrust bearing portion of the composite bearing 86 is constituted by a plurality of fan-shaped thrust pieces (a layer of a sliding bearing material (for example, white metal) is formed on a surface that comes into contact with the thrust collar 85). The thrust pieces are swingably and elastically supported. Casing 7
Is a cylindrical structure having a main role of supporting the stationary blades 92, sealing the steam 99, and the like, and is installed on a base 97 (a part of which is shown in FIG. 3). The device 9 is divided into upper and lower parts because of the necessity of assembling the device 9. The casing 7 is provided with an inspection port 79 and the like, and a condenser (not shown) is installed on the discharge end side of the exhaust gas 98 of the casing 7.

[0007] Twenty-seven sets of stationary blades 92 of the steam turbine device 9 are attached to the casing 7 via a plurality of stationary blade holders 71. The stationary blades 92 into which the steam 99 immediately flows in from the steam control valve 91 flows. An inlet 72 for steam 99 is formed in the stationary blade holder 71 to be attached. In addition, 96 is a base plate installed on the upper surface of the foundation 97,
Reference numeral 95 denotes a slide plate provided above the base plate 96. Numeral 61 denotes a bearing box on the drive side end side. In this case, the bearing box 61 is installed on a foundation 97, accommodates the composite bearing 86 and the coupling 81 therein, and includes a low-speed rotating device 8
An electric motor 83 for driving a low-speed rotating device having a driving portion meshing with the second gear is provided at the upper part. Numeral 62 denotes a bearing box on the side opposite to the driving end, which in this case is supported by a beam 78 for bearing box support fixed to the casing 7 near the discharge end, and houses the journal bearing 4 therein. ing.

[0008] Of these bearings, the journal bearing portion of the composite bearing 86 and the journal bearing 4 are connected to the steam turbine device 9.
, And the thrust bearing portion of the composite bearing 86 supports the thrust force due to the difference between the reaction force and the canceling force. The magnitude and direction of the thrust force are not constant because they depend on the load condition of the steam turbine device 9 and the like. This is why the thrust collars 85 are formed so as to sandwich the composite bearing 86 from both sides. The diameter of the turbine shaft 8 at the portion supported by the composite bearing 86 is large enough to transmit the driving torque of the rotary load device and withstand the short-circuit torque of the synchronous generator when the rotary load device is a synchronous generator. ing. Further, the reason why the composite bearing 86 is disposed near the other end (load-side end) of the turbine shaft 8 is that a gap between the stationary blade 92 and the moving blade 93 at the start of operation of the steam turbine device 9 or the like. Gap length δ in the axial direction of
(See FIG. 4).

At the start of operation, the steam turbine apparatus 9 is rapidly heated from a cold (normal temperature) state to a high temperature state by the inflowing steam 99. However, the temperature of the turbine shaft 8 is higher than the temperature of the casing 7 due to heat capacity and heat transfer. The temperature rises first.
The variation of the gap length δ can be suppressed by setting the base point of the thermal expansion due to the temperature rise near the inflow port 72 of the steam 99, which is the high-temperature generating section. The gap length δ is an element that affects the loss amount (turbine loss amount) of the steam turbine device 9, and the relationship between the gap length δ and the turbine loss amount has a V-shaped relationship, and the turbine loss amount is the lowest. It is known that there exists an optimum gap length δ. Steam turbine device 9
In the case of, since the base point of the thermal expansion of the turbine shaft 8 is the composite bearing 86 combined with the thrust collars 85, 85,
The composite bearing 86 is provided at the above-mentioned portion. And then
A lubricating oil (not shown) flows through the composite bearing 86 and the journal bearing 4. The bearings for load and thrust force are lubricated with the lubricating oil, and the bearings are cooled to required temperatures by the lubricating oil. I have.

By the way, in addition to the axial exhaust type steam turbine device, depending on the system configuration (whether or not combined power generation is used) and the plan of the whole plant such as the building and the site, etc., the downward exhaust type steam turbine device may be used. May be adopted. Next, an example of the downward exhaust type steam turbine device will be described with reference to FIG. Here, FIG. 5 is a longitudinal sectional view showing a main part of the downward exhaust type steam turbine device of the reference example. In the following description, the same parts as those of the conventional steam turbine device shown in FIGS. 3 and 4 are denoted by the same reference numerals, and description thereof will be omitted. In addition, in the drawings used in the following description, only reference numerals shown in FIGS. 3 and 4 are represented as much as possible.

In FIG. 5, 9A is different from the conventional steam turbine device 9 shown in FIGS. 3 and 4 in that the casing 7 and the turbine shaft 8 are replaced by the casing 7A and the turbine shaft 8A, and the turbine shaft 8A It can be said that this is a steam turbine device in which the end on the side from which the exhaust gas 98 is discharged is the drive-side end. The main difference between the casing 7A and the casing 7 of the steam turbine device 9 is that the portion where the steam 99 is discharged as the exhaust 98 is configured to correspond to the downward exhaust type. Therefore, the turbine shaft 8A is coupled to the turbine shaft 8 of the steam turbine device 9 at an end on the side where the exhaust 98 is discharged (an end on the exhaust discharge side).
Are formed. Accordingly, the turbine shaft 8A is supported by the journal bearing 5 near the exhaust discharge end (the drive end in this case), and the end (the end opposite to the exhaust discharge side). The end on the anti-exhaust discharge side, and
In this case, it is supported by a journal bearing 4 and a thrust bearing 3 in the vicinity of the opposite end (on the opposite side to the driving side).

The reason for disposing the thrust bearing 3 at this position is to suppress the variation of the gap length δ due to thermal expansion as in the case of the steam turbine device 9. Among these bearings, the journal bearings 4 and 5 support the load of the rotating part of the steam turbine device 9A, and the thrust bearing 3 supports the thrust force. Accordingly, the bearing box 61 is mounted on the foundation 97 at the end on the exhaust discharge side, and the bearing box 62 is mounted on the foundation 97 at the end on the non-exhaust discharge side. Further, the configuration of the thrust bearing 3 is such that a plurality of fan-shaped thrust pieces are disposed so as to face the side portions of the respective thrust collars 85, for example, the configuration of the thrust bearing portion of the composite bearing 86 of the steam turbine device 9. Is basically the same as

The diameter of the turbine shaft 8A at the portion supported by the journal bearing 5 is larger than the diameter of the turbine shaft 8A at the portion supported by the journal bearing 4 for the same reason as in the case of the turbine shaft 8. Has become. Further, since the turbine shaft 8A at the portion supported by the thrust bearing 3 does not need to support the driving torque of the rotary load device and the load at the rotating portion, the diameter of the turbine shaft 8A at the portion supported by the journal bearing 4 is larger than the diameter of the turbine shaft 8A. Is also thin. That is, the diameter of the turbine shaft 8A at the portion supported by the thrust bearing 3 of the steam turbine device 9A is a composite of the steam turbine device 9 when the specification of the steam turbine device 9A as the turbine is the same as that of the steam turbine device 9. The diameter is much smaller than the diameter of the turbine shaft 8 at the portion supported by the bearing 86. As a result, the average diameter of the thrust pieces of the thrust bearing 3 can be reduced as compared with the case of the composite bearing 86, and the thrust bearing loss generated in the thrust bearing can be reduced as compared with the steam turbine device 9. The base point of the thermal expansion of the turbine shaft 8A is the thrust bearing 3.

[0014]

The above-described axial-flow exhaust type steam turbine device 9 according to the prior art is advantageous in suppressing the variation of the gap length δ at the start of operation of the steam turbine device 9 and the like. Composite bearing 86 with bearing
Is disposed in the vicinity of the drive side end of the turbine shaft 8 (the end opposite to the exhaust discharge side). However, the diameter of the turbine shaft 8 at the portion supported by the composite bearing 86 is larger than the diameter at the portion supported by the journal bearing 4 for the above-described reason. For this reason, the average diameter of the thrust pieces of the thrust bearing portion of the steam turbine device 9 has to be larger than the average diameter of the thrust pieces of the thrust bearing 3 of the above-described downward exhaust type steam turbine device 9A. As a result, in the axial exhaust type steam turbine device 9, bearing friction loss of the thrust bearing portion is large.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to provide an axial exhaust type turbine device suitable for reducing a loss generated in a thrust bearing portion.

[0016]

According to the present invention, there are provided the following objects: 1) a turbine shaft which is a shaft to which a power generator for extracting power from a fluid having kinetic energy is attached, and an axial direction of the turbine shaft; A casing that discharges the fluid flowing along the vicinity of one end of the turbine shaft as exhaust gas in a direction substantially parallel to the axial direction, and a casing disposed near the one end of the turbine shaft. A thrust bearing for supporting a thrust force acting on the turbine shaft in the axial direction thereof, wherein the turbine shaft is driven by the turbine device at the other end portion opposite to the one end portion. This is achieved by having a load connection for connecting a rotary load device.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the following description, FIG.
9A of a downward exhaust type steam turbine device shown in FIG.
The same parts as those described above are denoted by the same reference numerals, and description thereof will be omitted. FIG. 1 is a longitudinal sectional view showing a part of an axial flow exhaust type steam turbine device according to an embodiment of the present invention, partially cut away, and FIG. 2 is a gap length δ and a turbine loss amount of the steam turbine device. FIG. 4 is an explanatory diagram for explaining a relationship with the above. In FIG. 1, 1
Is different from the conventional axial-flow exhaust type steam turbine device 9 shown in FIG.
This is an axial-flow exhaust-type steam turbine device in which a turbine shaft 2, a thrust bearing 3, and a journal bearing 5 are used, and the thrust bearing 3 is disposed near an end on the exhaust discharge side of the turbine shaft 2.

The turbine shaft 2 is located at the end of the exhaust shaft 98 (exhaust exhaust end and opposite to the driving end) with respect to the turbine shaft 8 of the steam turbine device 9. Is characterized in that the thrust bearing 3 is disposed in the vicinity of the end of the thrust bearing 3). The turbine shaft 2 is thus supported by journal bearings 5 near the drive end (the other end in this case) and journal bearings 4 and 5 near the non-drive end. Thrust bearing 3
Supported by Then, when the specification of the steam turbine device 1 as the turbine is the same as that of the steam turbine devices 9 and 9A, the portion of the turbine shaft 2 supported by the journal bearing 5, the portion supported by the journal bearing 4, and The diameter of the portion supported by the thrust bearing 3 is equivalent to that of the steam turbine device 9A. In addition, the turbine shaft 2
The base point of thermal expansion is the thrust bearing 3 similarly to the steam turbine device 9A.

FIG. 1 shows an embodiment of the present invention.
The steam turbine device 1 according to the present invention has the above-described configuration.
Investigated the relationship between the gap length δ and the turbine loss, and
Invented the invention. That is, the gap length δ and the turbine loss amount
Is related to a V-shape as conventionally known.
Therefore, the turbine loss amount L is equal to the minimum turbine loss amount L. _m
Optimal gap length δ_mCertainly exists, but
Suitable gap length δ_mNear the gap length δ
It was confirmed that the amount of change in the loss amount L was extremely small.
That is, the optimum gap length δ_mIn the vicinity of the gap length δ,
Bin loss L is the minimum turbine loss L_mMore than
However, the increase is slight (see FIG. 2).

This means that even if the starting point of the thermal expansion due to the temperature rise is set at a position distant from the inlet 72 of the steam 99, the turbine loss L caused by the increased gap length δ becomes the minimum turbine loss L _m , the starting point of the thermal expansion is set to the inlet 7 of the steam 99.
This means that it is not necessary to stick to the vicinity of 2. This invention was made by paying attention to this,
From the above, it must be prepared that the turbine loss L is slightly increased in the steam turbine device 1 as compared with the steam turbine device 9. However, the thrust bearing 3 is provided with the thrust bearing 3 having a small average diameter of the thrust piece. The amount of reduction in thrust bearing loss due to adoption is greater.
As a result, the total loss of the steam turbine device 1 of the present invention is smaller than that of the steam turbine device 9 of the conventional example.

Further, the reduction of the thrust bearing loss has the following advantages. That is, each part of the bearing of the conventional steam turbine device 9 is cooled to a required temperature by the lubricating oil as described above, and as a result, the supply amount of the lubricating oil is increased. For this reason, in the steam turbine device 9, the lubricating oil supply equipment (including oil tanks, pumps, valves and piping, etc.) becomes large, and the required power of lubricating oil supply auxiliary equipment (main oil pump, etc.) Is getting bigger. By reducing the thrust bearing loss in the steam turbine device 1,
This leads to downsizing of the lubricating oil supply equipment and reduction of auxiliary power, and the reduction of auxiliary power also has the advantage of reducing the loss amount of the steam turbine device 1 as a whole. In the above description, the axial exhaust type turbine device has been described as a steam turbine device. However, the present invention is not limited to this, and the present invention is suitably applied to a turbine device other than a steam turbine such as a gas turbine. .

[0022]

According to the turbine apparatus of the axial exhaust type according to the present invention, by adopting the structure described in the section of the means for solving the above-mentioned problems, the axial gap between the stationary blade and the moving blade can be improved. Since the thrust bearing loss is reduced by exceeding the increase in the turbine loss L due to the length δ deviating from the optimum gap length δ _m , the total loss of the turbine device can be reduced, and the thrust bearing loss can be reduced. By reducing the amount,
The lubricating oil supply equipment has been downsized and auxiliary power has been reduced,
The reduction of the auxiliary power also makes it possible to reduce the total loss of the turbine device, and also to reduce the manufacturing cost including the building of the steam turbine device.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a main part of an axial-flow exhaust type steam turbine device according to an embodiment of the present invention, partially cut away;

FIG. 2 is an explanatory diagram for explaining a relationship between a gap length δ and a turbine loss amount of the steam turbine device.

FIG. 3 is a longitudinal sectional view showing a main part of a conventional axial-flow exhaust type steam turbine device.

FIG. 4 is an enlarged sectional view of a portion S in FIG. 3;

FIG. 5 is a longitudinal sectional view showing a main part of a downward exhaust type steam turbine device of a reference example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Turbine device (steam turbine device) 2 Turbine shaft 3 Thrust bearing 4 Journal bearing 5 Journal bearing

Claims (1)

[Claims] 1. A turbine shaft which is a shaft to which a power generator for extracting power from a fluid having kinetic energy is attached, and said fluid flowing along the axial direction of the turbine shaft is supplied to one of the turbine shafts. A casing that is discharged as exhaust in a direction substantially parallel to the axial direction from near the end,
A thrust bearing disposed near the one end of the turbine shaft and supporting a thrust force acting on the turbine shaft in the axial direction thereof, wherein the turbine shaft is on the opposite side to the one end. An axial exhaust type turbine device having a load connecting portion for connecting a rotary load device driven by the turbine device to the other end portion of the turbine device.