JPH06221109A - High and medium pressure integral type steam turbine - Google Patents

Abstract

PURPOSE:To reduce temperature difference between an upper-casing side and a lower-casing side of a space surrounded by a turbine outer casing and an inner casing. CONSTITUTION:A plurality of bypass holes 21a, 21b are formed on a high pressure dummy circle 9 for bypassing a high pressure dummy 11 in a gap between the high pressure dummy circle 9 and a turbine rotor 10. A flow passage area of the upper-casing side bypass hole 21a is equalized to that of the lower-casing side pypass hole 21b, or a circumferential groove is formed on an end face of the high pressure dummy circle 9 on the outlet side of the high pressure dummy 11. Otherwise, a circumferential slit 16 which communicates a high pressure turbine exhaust chamber 15 with the outlet of the high pressure dummy 11 is sealed by a labyrinth seal or the like. At least one balance hole which communicates the high pressure turbine exhaust chamber 15 with a space 14 surrounded by a turbine outer casing 12 and an inner casing 13 is formed on a lower-casing side portion of a circular projection on the side of the turbine inner casing 13 serving as limit for the slit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high and medium pressure integrated steam turbine.

[0002]

2. Description of the Related Art FIG. 4 shows a structural example of a conventional high-intermediate-pressure integrated steam turbine. In FIG. 4, steam supplied from a boiler (not shown) flows in from the main steam pipe 1, expands in the speed control stage 2 and the high pressure turbine stage 3, and performs work.
Then, the high-pressure exhaust steam is guided from the high-pressure turbine outlet 4 to the boiler via the high-pressure turbine outlet pipe 5.

Further, the steam reheated in the boiler flows in from the intermediate pressure turbine inlet pipe 6 and expands in the intermediate pressure turbine 7,
It does the work and exits the medium pressure turbine exhaust pipe 8 and is directed to a low pressure turbine not shown.

Further, a part of the steam at the nozzle outlet of the speed control stage 2 passes through the high pressure dummy 11 in the gap between the high pressure dummy ring 9 and the turbine rotor 10, and passes through the turbine outer casing 12 and the inner casing 1.
It flows out into the space 14 surrounded by 3 and the turbine inner casing 13
The temperature difference between the inside and outside of the.

The high-pressure turbine exhaust chamber 15 and the outlet of the high-pressure dummy 11 are connected to the turbine outer casing 12 and the inner casing 13 of the turbine.
Are communicated with each other via a circumferential slit 16 provided between and to prevent the thrust of the high-pressure turbine from being unbalanced when the turbine is urgently stopped. That is, at the time of an emergency stop of the turbine, the pressure in the space 14 surrounded by the turbine outer casing 12 and the inner casing 13 sharply drops, but the steam in the high-pressure turbine exhaust chamber 15 passes through the slit 16 and the space. By flowing into 14, the pressure on both side surfaces of the annular projection (also referred to as blade ring corner portion) 17 on the turbine inner casing 13 side that defines the slit 16 becomes equal, and the thrust of the high-pressure turbine is balanced, and the thrust is balanced. Bearing damage is prevented.

[0006]

The conventional high-to-medium pressure integrated steam turbine described above has the following problems.

First, when the high-pressure dummy ring 9 is eccentric, the clearance between the high-pressure dummy 11, that is, the high-pressure dummy ring 9 and the turbine rotor 10 differs between the upper vehicle side and the lower vehicle side. As a result, the flow rate of steam passing through the high-pressure dummy 11 is different between the upper vehicle side and the lower vehicle side, so the turbine outer casing 12 and the inner casing 1
The temperature of the space 14 surrounded by 3 differs between the upper vehicle side and the lower vehicle side. When a temperature difference occurs between the upper vehicle compartment and the lower vehicle compartment, the difference in thermal expansion deforms the turbine outer casing 12, the inner casing 13, and the like, and the clearance of each part of the turbine changes in the circumferential direction. Contact and clearance will be excessive, resulting in poor performance.

Secondly, the structure of the high-pressure turbine exhaust chamber 15 is vertically asymmetrical, and the high-pressure turbine outlet pipe 5 is generally installed in the lower passenger compartment. Therefore, high pressure turbine paragraph 3
Of the exhaust gas from the vehicle, the exhaust gas on the lower vehicle side directly flows out to the outlet pipe 5, whereas the exhaust gas on the upper vehicle side passes around the turbine rotor 10 and reaches the outlet pipe 5, so there is a pressure loss during this period. Therefore, the pressure inside the high-pressure turbine exhaust chamber 15 may be higher on the upper vehicle side than on the lower vehicle side. When the pressure on the upper vehicle side in the high pressure turbine exhaust chamber 15 is higher than the pressure in the space 14 surrounded by the turbine outer casing 12 and the inner casing 13, the upper vehicle side inside the high pressure turbine exhaust chamber 15 is The low-temperature steam flows back into the space 14, and the temperature of the passenger compartment on the upper vehicle side becomes lower than that on the lower vehicle side. As a result, when there is a temperature difference between the upper compartment and the lower compartment, as described above, the turbine outer casing 12 and the inner casing 13 are deformed due to the difference in thermal expansion, and the clearances of the turbine parts in the circumferential direction. Changes to
The fins come into contact with each other and the clearance becomes excessive, resulting in deterioration of performance.

The present invention has been made in order to solve the above-mentioned problems of the prior art. Even if the high-pressure dummy ring is eccentric, the upper vehicle side of the space surrounded by the turbine outer casing and the inner casing. It is an object of the present invention to provide a high-intermediate-pressure integrated steam turbine that can reduce the temperature difference between the vehicle and the vehicle side.

Further, according to the present invention, the steam on the upper side of the high pressure turbine exhaust chamber is prevented from flowing back to the space surrounded by the turbine outer casing and the inner casing, and the upper side and the lower side of the space are prevented. It is an object of the present invention to provide a high-intermediate-pressure integrated steam turbine capable of reducing the temperature difference between the steam turbine and the side.

[0011]

In order to achieve the former object, the present invention according to claim 1 is a high-intermediate-pressure integrated steam turbine, wherein a high pressure dummy ring has a gap between the high pressure dummy ring and the turbine rotor. By forming a plurality of bypass holes that bypass the high-voltage dummy, the flow passage areas of the upper vehicle side bypass holes and the lower vehicle side bypass holes are made equal.

In order to achieve the former object, the present invention according to claim 2 is a high-intermediate-pressure integrated steam turbine, wherein a groove in the circumferential direction is provided on the end surface of the high-pressure dummy ring on the high-pressure dummy outlet side. is there.

In order to achieve the latter object, the present invention according to claim 3 is a high-intermediate-pressure integrated steam turbine, wherein the high-pressure turbine exhaust chamber is provided between the turbine outer casing and the inner casing. A circumferential slit that communicates with the outlet of the high-pressure dummy is sealed, and a high-pressure turbine exhaust chamber and a turbine outer casing are provided in the lower vehicle-side portion of the annular protrusion on the turbine inner casing side that limits the slit. At least one balance hole communicating with the space surrounded by is formed.

[0014]

According to the present invention as set forth in claim 1, a part of the nozzle outlet steam of the speed-control stage passes through a plurality of bypass holes formed in the high pressure dummy ring to form a turbine outer casing and an inner casing. It flows out into the enclosed space and reduces the temperature difference between the inside and outside of the turbine interior.

Even if the high pressure dummy ring is eccentric,
Since the flow passage area of the bypass hole is equal on the upper vehicle side and the lower vehicle side, the amount of steam passing through the bypass hole is the same on the upper vehicle side and the lower vehicle side. As a result, the temperature difference between the upper vehicle side and the lower vehicle side of the space surrounded by the turbine outer casing and the inner casing is reduced.

According to the second aspect of the present invention, when the high-pressure dummy ring is eccentric and the clearance between the high-pressure dummy, that is, the high-pressure dummy ring and the turbine rotor is larger on the side of the upper vehicle than on the side of the lower vehicle, the vehicle is on the upper side. Although the flow rate of steam flowing through the high pressure dummy on the side becomes larger than that on the lower vehicle side, a part of the steam flowing on the upper vehicle side flows to the lower vehicle side through the circumferential groove provided on the end surface of the high pressure dummy ring on the high pressure dummy outlet side. As a result, the amount of steam flowing from the high-pressure dummy to the space surrounded by the turbine outer casing and the inner casing is equal on the upper vehicle side and the lower vehicle side, and the temperature difference between the upper vehicle compartment and the lower vehicle compartment is reduced. .

Further, according to the present invention as set forth in claim 3, by sealing a circumferential slit that connects the high pressure turbine exhaust chamber and the outlet of the high pressure dummy, the high pressure turbine exhaust chamber is sealed from the upper side of the high pressure turbine exhaust chamber. The backflow of steam to the space surrounded by the turbine outer casing and the inner casing is eliminated. As a result, the temperature difference between the upper and lower vehicle compartments in the space is reduced.

Even if the slit is sealed, when the turbine is stopped in an emergency, the steam in the high pressure turbine exhaust chamber is formed in the balance hole formed in the lower vehicle side portion of the annular projection on the turbine inner casing side that limits the slit. Since it flows into the space surrounded by the turbine outer casing and inner casing,
The thrust of the high-pressure turbine is balanced and damage to the thrust bearing is prevented.

[0019]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of the present invention as set forth in claim 1. The same parts as those shown in FIG. 4 are designated by the same reference numerals and their duplicate description will be omitted.

In this embodiment, in the high-intermediate-pressure integrated steam turbine, the high-pressure dummy ring 9 is provided with a plurality of bypass holes 21a and 21b for bypassing the high-pressure dummy 11 in the gap between the high-pressure dummy ring 9 and the turbine rotor 10. However, the flow passage area of the bypass hole 21a on the upper vehicle side and the bypass hole 21b on the lower vehicle side
Is equal to the flow path area of. In order to make these flow passage areas equal, for example, the bypass holes 2 having the same diameter are used.
The same number, for example, two of the high pressure dummy rings 9 may be provided on the upper vehicle side and the lower vehicle side of the high pressure dummy ring 9, respectively.

Therefore, according to this embodiment, the speed control stage 2
A part of the steam at the nozzle outlet of the above flows out into a space 14 surrounded by the turbine outer casing 12 and the inner casing 13 through a plurality of bypass holes 21a and 21b formed in the high-pressure dummy ring 9. The temperature difference between the inside and outside of the turbine inner casing 13 is reduced.

Even if the high-pressure dummy ring 9 is eccentric, since the flow passage area of the bypass hole 21a on the vehicle side is equal to the flow passage area of the bypass hole 21b on the vehicle side, the bypass hole 21a on the vehicle side is formed. The amount of steam passing through the bypass hole 21b on the lower vehicle side becomes equal. As a result, the turbine outer casing 1
The temperature difference between the upper vehicle side and the lower vehicle side of the space 14 surrounded by 2 and the inner vehicle compartment 13 is reduced.

Next, FIG. 2 shows an embodiment of the present invention as set forth in claim 2. The same parts as those shown in FIG. 4 are designated by the same reference numerals, and duplicate explanations are omitted. . In this embodiment, in the high / intermediate pressure integrated steam turbine, a groove 31 in the circumferential direction is formed on the end surface of the high pressure dummy ring 9 on the outlet side of the high pressure dummy 11.
Is provided.

Therefore, according to the present embodiment, when the high-pressure dummy ring 9 is eccentric and the clearance between the high-pressure dummy 11, that is, the high-pressure dummy ring 9 and the turbine rotor 10 is larger on the upper vehicle side than on the lower vehicle side, Although the flow rate of steam flowing through the high-pressure dummy on the vehicle side becomes larger than that on the lower vehicle side, part of the steam flowing on the upper vehicle side gets off through the circumferential groove 31 provided on the end surface of the high-pressure dummy ring 9 on the outlet side of the high-pressure dummy 11. Flowing to the side. As a result, the amount of steam flowing from the high-pressure dummy 11 to the space 14 surrounded by the turbine outer casing 12 and the inner casing 13 becomes equal on the upper vehicle side and the lower vehicle side, and the temperature difference between the upper vehicle compartment and the lower vehicle compartment. Is alleviated.

Next, FIG. 3 shows an embodiment of the present invention according to claim 3. In this embodiment, the slit 16 in the high-intermediate-pressure integrated steam turbine shown in FIG. 4, that is, between the turbine outer casing 12 and the inner casing 13 is provided and the outlets of the high-pressure turbine exhaust chamber 15 and the high-pressure dummy 11 are provided. The slit 16 in the circumferential direction that communicates with the portion is sealed by, for example, a labyrinth seal 41, and the high pressure turbine exhaust chamber 15 is provided in the lower vehicle side portion of the annular protrusion 17 on the turbine inner casing 13 side that limits the slit 16. At least one balance hole 42 communicating with the space 14 surrounded by the outer casing 12 and the inner casing 13 is formed.

Therefore, according to the present embodiment, by sealing the circumferential slit 16 that connects the high-pressure turbine exhaust chamber 15 and the outlet of the high-pressure dummy 11 with each other, the high-pressure turbine exhaust chamber 15 can be mounted from the upper side of the vehicle. , Turbine outer casing 1
The backflow of steam to the space 14 surrounded by 2 and the inner casing 13 is eliminated. As a result, the temperature difference between the upper vehicle side and the lower vehicle side of the space 14 is reduced.

Even if the slit 16 is sealed, the high pressure turbine exhaust chamber 1 will be operated when the turbine is stopped in an emergency.
The steam in 5 passes through the balance hole 42 formed in the lower vehicle side portion of the annular projection 17 on the turbine inner casing 13 side that defines the slit 16, and passes through the turbine outer casing 12 and the inner casing 1
Since it flows into the space 14 surrounded by 3, the thrust of the high-pressure turbine is balanced and damage to the thrust bearing is prevented.

[0029]

As described above, claims 1, 2, and 3 are provided.
According to any of the present invention described, in the high-medium pressure integrated steam turbine, since it is possible to reduce the temperature difference between the upper vehicle side and the lower vehicle side of the space surrounded by the turbine outer casing and the inner casing, Deformation of the turbine outer casing and inner casing due to the difference in thermal expansion is prevented, and the clearance of each turbine part does not change in the circumferential direction.As a result, fin contact and excessive clearance are eliminated and performance is reduced. Can be prevented.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a high / intermediate pressure integrated steam turbine according to the present invention as set forth in claim 1.

FIG. 2 is a sectional view showing an embodiment of a high / intermediate pressure integrated steam turbine according to the present invention as defined in claim 2;

FIG. 3 is a cross-sectional view of essential parts showing an embodiment of a high-intermediate pressure integrated steam turbine according to the present invention as defined in claim 3.

FIG. 4 is a sectional view showing a conventional high / intermediate pressure integrated steam turbine.

[Explanation of symbols]

 9 High-pressure dummy ring 10 Turbine rotor 11 High-pressure dummy 12 Turbine outer casing 13 Turbine inner casing 14 Space surrounded by turbine outer casing and inner casing 15 High-pressure turbine exhaust chamber 16 Slit 17 Annular protrusion 21a, 21b Bypass hole 31 Groove 41 Labyrinth seal 42 Balance hole

Claims (3)

[Claims] 1. In a high-intermediate-pressure integrated steam turbine, a plurality of bypass holes for bypassing a high-pressure dummy in the gap between the high-pressure dummy ring and the turbine rotor are formed in a high-pressure dummy ring, and the flow of the bypass hole on the vehicle side is increased. A high-intermediate-pressure integrated steam turbine, characterized in that a road area and a flow path area of a bypass hole on the getting-off side are equalized. 2. A high-middle pressure integrated steam turbine in which a groove in the circumferential direction is provided on the end surface of the high-pressure dummy ring on the high-pressure dummy outlet side. 3. A high-intermediate-pressure integrated steam turbine, wherein a circumferential slit provided between an outer casing of a turbine and an inner casing of a turbine for communicating between a high-pressure turbine exhaust chamber and an outlet of a high-pressure dummy is sealed, At least one balance hole for communicating the high-pressure turbine exhaust chamber with the space surrounded by the turbine outer casing and the inner casing is formed in the lower vehicle-side portion of the annular protrusion on the turbine inner casing side that defines the slit. A high-intermediate-pressure integrated steam turbine characterized by the above.