JPS62225701A - Steam turbine - Google Patents

Abstract

PURPOSE:To improve performance and/or reliability of a steam turbine by providing disc parts of a multi-staged turbine rotary shaft with drilled balance holes of a command diameter and attaching regulating plates with regulating orifices to specified balance holes to make the passage area of said balance holes be determined at will. CONSTITUTION:Balance holes 7 are drilled out in disc parts of a rotary shaft 3 fitted with turbine blades 4, said balance holes being located on the same circumference around said rotary shaft 3 and with the same peripheral pitch between each other. Regulating plates (orifice) 9 made of a erosion-resisting material are fitted to said balance holes 7 and a regulating hole 10 is provided to each of said regulating plates 9, the inside diameter of said regulating hole 10 being smaller than that of said balance holes 7. Said regulating plates 9 are prepared with regulating holes 10 of various diameters to be selected at will. Attaching each of said regulating plates 9 to each balance hole of the rotary shaft at each stage and varying the diameters of regulating holes 10 of said regulating plates 9 at respective stages, distributed leak steam can be either blown into or induced from main steam Mo.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention relates to a single steam turbine, and particularly relates to a turbine installed on a rotating shaft.
The present invention relates to a steam turbine capable of adjusting the amount of steam passing through a balance hole to an optimum value.

(Prior Art) Each stage of a steam turbine includes a nozzle 2 formed in a nozzle diagonal frame 1, as shown in a partial cross section in FIG.
A turbine stage is constructed from the turbine blades 4 installed on the rotating shaft 3 located on the downstream side of the nozzle 2.
Mainstream steam M. is from the nozzle 2 to the turbine blade 4 (
) through the turbine blades 4
A rotational force is applied to the i-axis 3. On the nozzle diaphragm 1, a labyrinth packing 5 in which a large number of teeth are implanted is disposed on a surface facing the rotating shaft 3, and limits leakage steam M1.

The steam M1 leaking from the rinse gasket 5 passes through the passage 6 between the nozzle diaphragm 1 and the rotating shaft 3,
A part of it flows to the turbine blade 5 as shown by arrow M2,
The remaining steam M3 passes through the balance hole 7 formed in the rotating shaft 3 and flows to the next stage as shown by the arrow.

Especially leakage steam flow M2 among the above-mentioned leakage distribution steam M, M3
is mainstream steam M. It interferes with the steam flow when mixing into the steam turbine, but does not significantly affect the performance of the steam turbine. The test results are shown in Figure 10, where the horizontal axis shows the leakage distribution steam M2.
If we take the internal loss in the turbine on the vertical axis, the leakage distribution steam M2 becomes the mainstream steam M as shown by the arrow in Fig. 9. In the case of a mixed state in which the steam is blown out to
η is increasing.

On the other hand, the leaked distributed steam M2 is in the opposite direction to the arrow shown in FIG. 9, and is the mainstream steam M. In the state of suction from t, internal performance improves to a certain extent as m of leaked distributed steam M2 increases, but further increase leads to an increase in internal loss. In this way, the leaked distribution steam M2 is the mainstream steam M. There exists an optimal leakage distribution steam M2 leg that provides maximum suction and maximum improvement in internal performance.

As described above, in order to operate the internal performance in each stage at its best, the mainstream steam M is set as the optimal amount of leakage distribution steam M2. It is economically advantageous for steam turbine operation to draw in air from above. To achieve this, the optimum leakage distribution steam M
2 h! 9 can be adjusted to allow suction from the mainstream steam MO.

(Problems to be Solved by the Invention) However, a steam turbine usually has a configuration in which multiple pairs of nozzles 2 and turbine blades 4 are arranged close to each other, as shown in FIG. Since the gap between the disk parts of the implanted rotating shaft 3 is narrow, it is necessary to drill the balance hole 7 in the axial direction of the rotating shaft 3 with a drill as if it were a skewer. The inner diameter and number of the balance balls 7 cannot be arbitrarily selected. Therefore, in most steam turbines, the diameter and number of balance holes 7 must be the same in each stage.

If the diameter and number of balance holes 7 in each stage are equal, the pressure between the nozzle 2 and the turbine blade 4 will be different for each stage, so the optimum 1T for a particular stage
11 Leakage distribution steam M2 and mainstream steam M. Even if the suction of M is achieved, in other paragraphs the leakage distribution steam M
2 is mainstream steam M. Situations often occur in which the steam turbine's performance is degraded by blowing out to the steam turbine.

On the other hand, mainstream steam M is leakage distribution steam for the purpose of improving the performance of the steam turbine. For the purpose of improving the reliability of the steam turbine rather than improving the performance, the mainstream steam M of the leakage distribution steam is caused to be sucked into the leakage distribution steam. There are cases where you may be asked to make a speech bubble. In other words, mainstream steam M. In a steam turbine that uses high-temperature steam as a steam turbine, the implanted part of the turbine blade 4 installed in the rotating shaft 3 is subjected to high stress due to the centrifugal force exerted during rotation, and is also rubbed by high-temperature mainstream steam. 4 and the rotating shaft 3, the strength of their materials will be reduced and they will be placed under very severe conditions.

Therefore, in order to prevent the strength of the material in the blade implantation portion from decreasing, the blade implantation portion may be cooled by introducing relatively low-temperature cold 1 (I steam).

In this case, as shown in FIG. 12, there is a main stream of natural air M in the nozzle diaphragm 1 in the first paragraph.

A labyrinth para 4:n 9 is attached to the gasket head 8 arranged adjacent to and isolated from the labyrinth gasket 9, and relatively low-temperature cooling steam M4 is allowed to flow into the gap between the rinse gasket 9 and the rotating shaft 3. This cooling steam M4 is guided to a passage 6 through a gap between a labyrinth packing 5 provided on the nozzle diaphragm 1 and the rotating shaft 3.

A part of the cooling steam M4 that has entered the passage 6 is directly converted into mainstream steam M from the passage 6. The remaining cold W steam passes through the balance hole 7 and flows out to the next stage.

Even in a lifting platform that uses such leakage distribution steam as cooling steam, if the hole diameter d3 and the number of balance holes 7 in each stage are constant, the mainstream steam M in the stage is
. There is a problem in that the water flows into the passage 6 and some parts are not sufficiently cooled.

The present invention was made in consideration of the above-mentioned circumstances, and it selects the amount of steam passing through the balance hole to a desired value, eliminates the disturbance in the mainstream steam caused by the leaked steam, and improves the performance and reliability of the steam turbine. The purpose is to provide a hot air turbine that can be improved.

[Structure of the Invention] (Means for Solving and Overcoming Problems) In order to solve the problems of the above-mentioned prior art, the present invention drills balance balls of the same diameter in the disc portion of the rotating shaft in multiple stages, and reduces the drilling area. This is characterized by the fact that the perforation area of the balance hole can be arbitrarily set by installing an adjustment plate to fit the required adjustment hole in the oversized balance hole.

(Function) With the above configuration, the hole diameter of the balance hole is drilled at the largest inner diameter among those adjusted in each stage, and the adjustment hole with any desired inner diameter can be easily selected using the adjustment plate. This makes it possible to adjust the speed of the cold n1 steam to each stage even when adjusting the leakage distributed steam to intentionally select the mixture to be mixed into the main stream, or to adjust the cold W steam f71.

(Example) Examples of the present invention will be described below with reference to FIGS. 1 to 8.
The same reference numerals are given to the parts common to those in the figures to FIG. 12 for explanation.

Figure 1 shows the positional relationship between the balance hole and the turbine blades, and the disk part of the rotating shaft 3 in which the targon blades 4 are implanted is located on the same circumference and circularly from the axis of the rotating shaft 3. A plurality of balance holes 7 are bored at equal intervals in the circumferential direction.

FIG. 2 shows a side sectional view of FIG. 1 with an adjusting plate (orifice) 9 made of a corrosion-resistant material attached to the balance hole 7. This adjustment plate 9 has three adjustment holes 10 with an inner diameter smaller than the perforation diameter J of the balance ball 7.
The diameter of the adjustment hole 10 can be arbitrarily selected within the range from 0 to the same diameter as the balance hole 7.
: Sea urchins are used for many different types of sea urchins, and this adjusting plate 9 is connected to the rotating shaft 3 of each row.
By inserting a balance ball 7 into the balance ball 7 installed at the bottom, it is possible to slightly change the hole diameter of the adjustment hole 1o in the adjustment plate 9 of each stage. M. It can be blown out or sucked in.

A specific example of the means for attaching the adjustment plate 9 will be explained below.
In the case of Fig. 2, there is a notched step 1 at the edge of the balance hole 7.
1 is formed, and one end of the adjustment plate 9 is caulked to remove this stepped portion 11.
It is fixed by folding it into the This caulking is
An example is shown in FIG. 3 as seen from the direction of the Δ arrow in FIG. 2, and as shown in FIG.

In order to ensure the 1^1 constant of the adjustment plate 9, FIG. Fully caulk 1 along the chamfered part 13 of the adjustment plate 9, which has been provided in advance according to the indicated size.
By bending the extra wall portion 14 formed by 2, it is possible to securely and firmly fix the adjusting plate 9 to the rotating shaft 3.

The adjusting plate 9 shown in Figs. 4 and 6 is rounded to allow steam to easily flow into the inlet side of the leaked air, but the steam is not easily accessible to people. In order to do this, insert the edge of the opening on the artificial side of the adjusting plate 9 as shown in FIG. The amount of steam passing through the balance hole 7 can be adjusted not only by changing the diameter of the adjustment hole 10 but also by selecting the shape of the opening edge on the steam inlet side. In addition, in FIG. 7, the thickness of the rotary shaft 3 is thicker on the mainstream steam inlet side than the disk side surface of the rotary shaft 3 by an amount corresponding to the formation of the notch step 11 for caulking. can prevent a decrease in strength.

FIG. 8 shows an embodiment in which the adjustment plate 9 is provided on the mainstream steam outlet side of the turbine blade 4. In this case, the method of fixing the adjustment plate 9 and the inflow of leakage distribution steam are shown. Of course, each of the above-mentioned means can be used for the side opening [1 edge shape, etc.].

(Effects of the Invention) As explained above, the present invention provides balance holes having the same diameter in the disk portion of a rotating shaft of multiple stages, and adjusting plates having required adjustment holes for balance holes with an excessively large hole area. Since the perforation area of the balance ball can be set arbitrarily by attaching a The performance of the turbine can be significantly improved.Also, even in the case of a balance hole that guides cooling steam, the amount of cooling steam to each stage can be adjusted by appropriately selecting the hole diameter of the adjustment hole in the adjustment plate. This allows cooling of the implanted part of the blade 1.
The reliability of the steam turbine can be greatly improved.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the positional relationship between a balance hole and a blade in a steam turbine to which the present invention is applied, FIG. 2 is a sectional view of a main part showing an embodiment of the present invention, and FIG. , FIG. 4 is a sectional view of a main part showing another modification of the present invention, FIG. 5 is a view along arrow B in FIG. 4, and FIG.
FIGS. 7 and 8 are enlarged cross-sectional views of the main parts without showing still other modifications of the present invention, and FIG. 9 shows a nozzle diaphragm for one stage in a conventional steam bottle. FIG. 10 is a vertical cross-sectional view showing the turbine blades, etc., showing leakage distribution steam M ♀ and mainstream steam M. Figures 11 and 12 are explanatory diagrams showing the positional relationship of each stage in a conventional steam turbine. 1... Die rod 1 flam, 2... Nozzle, 3... Rotating shaft, 4... Turbine blade, 5... Labyrinth packing, 6... Passage, 7... Balance ball, 8・・・
・Packing head, 9...adjustment plate, 10...adjustment hole, 11...notch step, 12...caulking groove, 13...
- Chamfered portion, 14...Excess portion. Applicant's agent Hisashi Hatano Figure 2 Figure 3 Figure 4 Figure $5 Figure 6 Figure θ Figure 1 Theta

Claims (1)

[Claims] 1. Balance holes with the same diameter are drilled in the disc portion of the rotary shaft of multiple stages, and balance holes with an excessively large drilled area are fitted with adjustment plates having the required adjustment holes. A steam turbine characterized in that the perforation area can be arbitrarily set. 2. The steam turbine according to claim 1, wherein the outer periphery of the adjustment plate is caulked and fixed to the periphery of the balance hole. 3. The inner circumferential edge of the adjustment plate on the entrance side of the adjustment hole is formed into an arcuate and angular cross-section, and these adjustment plates are appropriately selected and mixed and arranged.
The steam turbine described in Section. 4. The steam turbine according to any one of claims 1 to 3, wherein the adjustment plate is provided so as to be in contact with the vicinity of the rear surface of the disk.