JP2548264Y2 - Mixed-pressure steam turbine - Google Patents

Description

[Detailed description of the invention]

 [Purpose of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mixed-pressure steam turbine for mixing high-pressure steam and low-pressure steam under preferable conditions.

[0002]

FIG. 3 shows a conventional mixed-pressure steam turbine, in which a turbine casing CA is divided into two parts along an axis C, and has an upper half turbine casing 13 and a lower half turbine casing 14, Upper half turbine casing at axis C
13 and the lower half turbine casing 14 are overlapped and cover the turbine rotor R.

The upper half turbine casing 13 that covers the turbine rotor R has a high-pressure steam inlet 17 for receiving high-pressure steam on one side. The paragraph connected to the high-pressure steam inlet 17 is a first paragraph FST in which the nozzle 5 and the moving blade 6 are paired.
G, guide vanes 7, and rotor blades 8 are arranged in the following order along the axis C. The intermediate paragraph SSTG, which is a pair of intermediate blades SSTG, is a Curtiss paragraph called a so-called double speed type.

On the other hand, the paragraph part of the lower half turbine casing 14 that covers the turbine rotor R is the upper half turbine casing.
It is asymmetric with respect to the paragraph section of the thing 13, and firstly, a moving blade row for implanting the moving blade 6 in the turbine rotor R (a rotating row of rotor blades implanted for the turbine rotor). ), A low-pressure steam inlet portion 17b for receiving low-pressure steam is provided on the inlet side of the bucket row (after the bucket row in the drawing). The low-pressure steam inlet 17b is divided by a barrier B into a steam chamber so that the low-pressure steam flows through the bucket row. Further, at the back of the barrier B that divides the steam chamber, the moving blades 8 forming the same moving blade row as the moving blades 8 of the above-mentioned intermediate paragraph SSTG are arranged.

On the outlet side of the intermediate stage SSTG, the upper and lower half turbine casings 13 and 14 and a mixing chamber MR opened at a target position, and the downstream side along the axis C from the mixing chamber MR is the upper and lower half. Section TST consisting of the turbine casings 13 and 14 and nozzles 11a and rotor blades 12a at target positions
G, nozzle 11b , 3rd paragraph part FSTG consisting of rotor blade 12b
Are arranged in the following order.

In the mixed-pressure steam turbine having the above structure, high-pressure steam from the high-pressure steam inlet 17 reaches the mixing chamber MR via the first stage FSTG and the middle stage SSTG. Further, the low-pressure steam from the low-pressure steam inlet 17b is inverted through the moving blades 6 and reaches the mixing chamber MR. In the mixing chamber MR, the high-pressure steam and the low-pressure steam merge, flow as mixed steam into the second paragraph section TSTG and the third paragraph section FSTG, and work during this time.

[0007] The mixed-pressure steam turbine, in which high-pressure steam and low-pressure steam are skillfully used in this way, makes full use of high- and low-pressure steam energy so that a large output can be obtained in a small type. ing.

[0008]

Generally, in this type of steam turbine, it is known that the steam passing through one paragraph section is reduced to about half the pressure. 100Kg / cm ² And the low pressure vapor pressure is 50Kg / cm ² In this case, it has been experienced that adding low-pressure steam to high-pressure steam after passing through the first paragraph obtains a desired work efficiency.

However, for example, when the high-pressure vapor pressure is 150 kg / cm
^Two And the low pressure vapor pressure is 100Kg / cm ² In the case of, the conventional multi-pressure steam turbine cannot fully utilize the energy of the low-pressure steam, and the work efficiency does not increase more than expected, so that the pressure of the low-pressure steam must be reduced. There is a disadvantage that the low pressure vapor pressure cannot be used as it is.

In view of the above, the present invention is based on the above-mentioned circumstances, and when mixing low-pressure steam into high-pressure steam, the mixed pressure is improved without any adjustment of the pressure of the low-pressure steam to obtain high work efficiency. The purpose is to publish the steam turbine. [Structure of device]

[0011]

SUMMARY OF THE INVENTION The present invention is directed to a two-part turbine casing, in which an upper half turbine casing has a high-pressure steam inlet and a lower half turbine casing. The high pressure steam
A low-pressure steam inlet that forms an opening in a direction opposite to the opening of the air inlet is provided.The turbine rotor that is covered by the upper half turbine casing has one end from the low-pressure steam inlet at the high-pressure steam inlet wall. A front row of rotor blades receiving the steam is arranged, and the other is arranged in the following order: a nozzle, a first stage section including the moving blades, a guide blade, and an intermediate stage section including the moving blades, and the lower half turbine casing. On the turbine rotor to be covered, one is formed at the lower pressure steam inlet, one of which is a nozzle, and the other is a lower half front paragraph section composed of a moving blade, and the other is a rear blade row, a guide blade, The middle paragraph section consisting of wings is arranged in the following order, high pressure steam passing through the first paragraph section and middle paragraph section from the high pressure steam inlet section, and inversion passing through the lower half front paragraph section from the low pressure steam inlet section. Mixed with the low-pressure steam that is formed on the outlet side of the middle stage section. In which was allowed mixed each other in the chamber.

[0012]

According to the above construction, the turbine rotor covered by the lower turbine casing is provided with the lower half front paragraph section comprising a pair of nozzles and rotor blades. The pressure energy of the low-pressure steam passing through is converted into velocity energy by a nozzle,
This velocity energy is converted to work by the rotor blades. Also, the front rotor row provided on the turbine rotor, which is overlaid on the upper half turbine casing, only changes the flow direction of the low-pressure steam.

Accordingly, only the low-pressure steam passing through the lower half front paragraph is reduced in pressure, and the remaining low-pressure steam hardly sees a pressure drop when passing through the front rotor blade row. When the low-pressure steam is mixed with the low-pressure steam, the pressure of the low-pressure steam can be reduced to half of the pressure of the high-pressure steam.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the mixed-pressure steam turbine according to the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic view of a mixed-pressure steam turbine according to the present invention, in which an upper half turbine casing 13 and a lower half turbine casing 14 are shown. As shown in FIG. 2, the upper half turbine casing 13 and the lower half turbine casing 14 are of a so-called axial flow type, which are overlapped on an axis C and are covered along the axis of the turbine rotor R. Further, a high-pressure steam inlet 17 for receiving high-pressure steam is provided on the minus side of the upper half turbine casing 13, and the high-pressure steam inlet 17 is provided in the lower half turbine casing 14 symmetrically with the high -pressure steam inlet 17. A low-pressure steam inlet 18 which forms an opening in a direction opposite to that of the opening is provided.

A front rotor blade row 10 is formed as an annular row on one side with a high pressure steam inlet wall 17a of a turbine rotor R covered by an upper half turbine casing 13 as a boundary. ―
In the other half, a first paragraph section having the nozzle 5 and the moving blade 6 as a pair, and an intermediate paragraph section having the guide blade 7 and the moving blade 8 as a pair are formed in an upper semicircular shape with the axis C as a boundary. Provided in the first paragraph,
The middle paragraph section constitutes the section section.

On the other hand, a nozzle 9 is provided on the turbine rotor R in a semi-circular manner around the axis C so as to communicate with a low-pressure steam inlet 18 and is provided on the turbine rotor R and covered by a lower half casing casing 14. A lower half front paragraph is formed by the nozzles 9 in the semi-annular row and the front blade row 10. This is the so-called rat-paragraph section. Further, the turbine rotor R has a low-pressure steam inlet wall.
Intermediate paragraph portions are arranged in the following order, with the rotor blades 6, the guide blades 7, and the rotor blades 8 paired with their backs 18a back to back. The outlet side of the middle stage section is a junction of high-pressure steam and low-pressure steam, and the junction has a relatively wide mixing chamber MR along the axis C.

The turbine rotor R passing through the mixing chamber MR
Is provided with a second paragraph section comprising an annular row of nozzles 11a and rotor blades 12a, and a third paragraph section comprising an annular row of nozzles 11b and rotor blades 12b.

Thus, in the above configuration, the high-pressure steam is supplied to the upper half turbine casing 13, as shown in FIG.
It flows to the high-pressure steam inlet 17 through the control valve CV, and from there, reaches the mixing chamber MR through the first stage of FIG. 1, the rotor blade 6 of the lower half turbine casing 14, and the middle stage, and during this time, First
The pressure of the high-pressure steam drops sharply because the nozzle 5 in the paragraph changes the speed energy to work, but the reduced pressure is maintained in the middle paragraph.

On the other hand, the low-pressure steam is supplied from the turbine casing 14 in the lower half of FIG.
The air flows into the low-pressure steam inlet 18 through the lower part 18, flows from the lower half front stage part in FIG. 1 through the moving blades 10 of the upper half turbine casing 13, and flows into the passages 20 and 21 in FIG. . Although the low-pressure steam is reduced in pressure in the lower half front paragraph because it changes from pressure energy to work, the vapor pressure does not decrease as much as the above-mentioned first paragraph and middle paragraph.

Accordingly, in the mixed-pressure steam turbine according to the present invention, a turbine rotor R provided on the lower half casing casing 14 comprises a nozzle 9 and a front blade row 10. Since the lower front paragraph (lat-paragraph) is provided and the pressure drop of low pressure steam is not so low as that of high pressure steam,
The pressure after the work of the high-pressure steam can be made almost the same, and the pressure reduction of the low-pressure steam, for example, without unnecessarily narrowing down the control valve, fully utilizing the pressure energy possessed by the low-pressure steam Can be.

While utilizing the pressure energy possessed by the low-pressure steam in this way, the depressurized low-pressure steam becomes almost the same pressure as the high-pressure steam and merges in the mixing chamber MR.
Thereafter, the pressure energy is converted into work in the second and third paragraphs, so that this type can obtain a large output for a relatively small proportion.

[0023]

As described above, the mixed-pressure steam turbine according to the present invention has a high pressure
Form a low-pressure steam inlet opening in the opposite direction to the steam inlet opening.
The low-pressure steam passes from the low-pressure steam inlet to the lower half
In the mixing chamber formed on the outlet side of the middle paragraph section
It has a configuration for mixing with high-pressure steam. With this configuration
The low-pressure steam forms a reversing flow,
The pressure of the low-pressure steam decreases due to the pressure loss, and is reduced to a predetermined value.
Therefore, the high-pressure steam that has passed through the first paragraph and the middle paragraph and the low-pressure steam that has passed through the lower half front paragraph can merge at almost the same pressure in the mixing chamber. Therefore, the high-pressure steam and the low-pressure steam can be effectively used without waste, and the development of this field is expected.

[Brief description of the drawings]

FIG. 1 is a schematic sectional side view showing an embodiment of a mixed-pressure steam turbine according to the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a schematic side sectional view showing one embodiment of a conventional mixed-pressure steam turbine.

[Explanation of symbols]

 5, 9 ... Nozzle 6, 8, 10 ... Blade 7 ... Guide blade 13 ... Upper half turbine casing 14 ... Lower half turbine casing 17 ... High pressure steam inlet 18 ... Low pressure steam inlet R … Turbin rotor MR… Mixing chamber

Claims (1)

(57) [Scope of request for utility model registration] 1. A turbine casing which is divided into two parts, of which the upper half turbine casing has a high-pressure steam inlet, and the lower half turbine casing has an opening of the high-pressure steam inlet. Open in opposite direction
A front rotor row having a low-pressure steam inlet portion forming a port, and a turbine rotor covered by the upper half turbine casing, one of which receives steam from the low-pressure steam inlet portion on one side with respect to the high-pressure steam inlet wall. And the other consisting of a nozzle and a rotor blade
The middle stage section consisting of the stage section, the guide blades, and the moving blades is arranged in the following order, and the turbine rotor, which is covered by the lower half turbine casing, has one of the nozzles and the moving blades at the boundary of the low-pressure steam inlet section. The lower half front paragraph section is formed, and the other is arranged in the following order with a rear blade row, a guide blade, and an intermediate paragraph section composed of a rotor blade receiving the high-pressure steam, and a first paragraph section from the high-pressure steam inlet section. The high-pressure steam passing through the middle stage and the low-pressure steam passing through the lower half stage from the low-pressure steam inlet are mixed with each other in a mixing chamber formed on the outlet side of the middle stage. A mixed-pressure steam turbine.