JPH0979003A - Gland main body installing structure of turbine chamber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To constitute a device in a simple structure, improve profitability and stability, and so carry out maintenance easily by feeding gland seal steam to an inside through a feed port after it is circulated once around a rotor in an annular passage from the feed port, in a gland main body installing part. SOLUTION: Gland seal steam is fed to a feed port 5, it is circulated once around a rotor passing the annular steam passage 15 formed on a gland main body installing part 10, and then it is led to the feed port 9 of gland seal steam. It is led from the feed port 9 to the annular flow-in passage of the gland main body, and it is supplied toward the outer peripheral surface of the rotor so as to obtain seal function. After that, it collects from the flow-out passage of the gland main body to a discharging port 6 together with air invaded from an outside, and it is discharged toward a gland condenser. Since high temperature gland seal steam is circulated once around the inner surface of the gland main body installing part 10 enclosing the rotor by a steam passage 10, the whole of he gland main body installing part 10 is heated uniformly so as to prevent generation of deviated heat deformation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gland seal structure applied to a low pressure turbine.

[0002]

2. Description of the Related Art A conventional technique will be described with reference to FIGS. The drawing shows the mounting portion of the gland main body 4 at the rear end of the low-pressure turbine. Here, the rotor blade 2 is mounted on the outer periphery of the rotor 2, and the low-pressure turbine casing covering the whole is also shown. A stator vane 12 is attached to the inner periphery of 1.

The rotor 2 rotates by passing steam from the stationary blades 12 toward the moving blades 13, and then the steam is guided by the flow guide 11 and discharged rearward from an outlet (not shown).

On the other hand, the rear end portion of the rotor 2 is rotatably supported by a bearing 3 provided in a bearing box 21. Further, the gland body 4 attached to the gland body mounting portion 10 of the low-pressure turbine casing 1 faces the outer peripheral surface of the rotor 2 to form a gland seal structure.

In this gland seal structure, the seal vapor is fed from the lower part toward the gland body mounting portion 10 by the feed pipe 5, and the ring chamber 4 of the gland body 4 is immediately fed from this feed portion.
It is fed straight into a. Then, after the sealing vapor spreads in the annular chamber 4a, it goes toward the outer peripheral surface of the rotor 2 and forms a seal there.

[0006]

In the prior art, as described above, the gland seal steam of the low pressure turbine is fed to the gland body 4 from one point below the gland body mounting portion 10. Therefore, the gland body mounting portion 10 is heated by the seal steam at this one point, and an uneven temperature distribution is generated in the gland body mounting portion 10.

For this reason, the ground body mounting portion 10 has a temperature difference between the upper and lower sides, and is thermally deformed as shown by reference numeral b in FIG. 7 to tilt the mounting surface of the ground body 4. As a result, the gland main body 4 is eccentric as indicated by reference numeral a in the figure, and the seal fins 7 supported by the gland main body 4 via the packing ring 6 come into contact with the peripheral surface of the rotor 2 to generate vibration.

Further, since the displacement amount of the gland body 4 depends on the temperature of the gland seal vapor to be fed, the displacement fin is predicted in advance to set the seal fin 7. Will be difficult.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems in the prior art and to obtain a highly economical and stable seal structure which has a simple structure and can be used with peace of mind. Is.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is a feed port for a gland seal vapor fed from the outside to a lower portion of a gland body mounting portion of a low pressure turbine casing. And a gland seal for supplying steam to the inside are provided with a supply port, and an annular steam passage is provided on the inner surface of the mounting part of the gland main body so as to encircle the rotor about one round and connect the supply port with the supply port. Providing a structure for mounting the main body of the turbine casing,
The gland seal steam is supplied from the supply port to the inside through an annular passage around the rotor about once.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS. It should be noted that portions common to the above-described conventional ones are designated by common reference numerals in the drawings to facilitate mutual understanding.

Reference numeral 10 denotes a gland body mounting portion of the low-pressure turbine casing. The gland body mounting portion 10 is formed by combining the upper half portion and the lower half portion into one body, and the rotor 2 is inserted through the center thereof. A gland body 4 is fixed to the gland body mounting portion 10 with a large number of bolts 8, and a packing ring 7a having a seal fin 7 is provided on the inner peripheral side thereof. An inflow passage 4a for the gland seal vapor is formed in an annular shape inside the gland body 4, and an outflow passage 4b for the gland seal vapor is similarly formed on the rear side thereof.

On the other hand, a ground steam supply port 5 is provided below the ground body mounting portion 10, and an exhaust port 6 for sending the ground steam to a ground condenser (not shown) is adjacent to the ground steam supply port 5.
However, next to it, supply ports 9 that communicate with the gland seal vapor inflow path 4a of the gland body 4 and supply the gland seal vapor to the inflow path 4a are provided.

Further, the ground body mounting portion 10 has
An annular steam passage 15 is provided so as to hollow out the inner surface thereof.
The feed port 5 and the feed port 9 located at the lower part of the rotor surround the rotor 2 so as to enclose the rotor 2, and the feed port 5 and the feed port 9 are communicated with each other.

The discharge port 6 communicates with the gland seal steam discharge passage 4b of the gland body 4, and collects the seal steam that seals the gland portion together with the air intruding from the outside and discharges it toward a gland condenser (not shown). To do.

According to the present embodiment configured as described above, the gland seal vapor is first guided to the feed port 5,
From there, it goes around the rotor 2 through an annular steam passage 15 formed in the gland main body mounting portion 10 so as to surround the rotor 2, and reaches the gland seal steam supply port 9.

Next, the gland seal vapor reaches the annular inflow path 4a of the gland body 4 from the supply port 9 and is supplied toward the outer peripheral surface of the rotor 2 to perform a sealing function.

After that, the air is gathered from the outflow passage 4b of the ground body 4 to the discharge port 6 together with the invading air from the outside, and is discharged to the ground condenser (not shown).

As described above, according to the present embodiment, the high-temperature gland seal steam fed to the gland main body mounting portion 10 extends from the feed port 5 to the feed port 9 through the steam passage 15 to the rotor. Since the inner surface of the gland body mounting portion 10 is surrounded by 2 and makes about one round, the gland body mounting portion 1
In the case of 0, the whole is heated almost uniformly, and the occurrence of uneven thermal deformation is prevented.

Therefore, there is no fear that the gland body 4 mounted on the gland body mounting portion 10 will be eccentric and the seal fin 7 will come into contact with the peripheral surface of the rotor 2 to generate vibration, and the functionally extremely stable seal structure. Is what you can get.

Although the present invention has been described above with reference to the illustrated embodiments, the present invention is not limited to such embodiments.
It goes without saying that various modifications may be made to the specific structure within the scope of the present invention.

[0022]

As described above, according to the present invention, since the high temperature gland seal vapor does not immediately flow into the gland body and the gland body mounting portion makes one round, the whole gland portion is kept at a substantially uniform temperature. As a result, the gland body mounting surface of the gland body mounting portion will not be tilted due to uneven heat deformation, and the gland body will be eccentric and the rotor and seal fins will come into contact with each other to generate vibration. Since it can be prevented, it is possible to obtain a gland body mounting portion with an excellent sealing structure that is safe and stable in operation, and is easy to maintain.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a ground main body mounting portion according to an embodiment of the present invention, in which a is a side surface, b is a BB cross section, and c is a CC cross section.

FIG. 2 is an explanatory view showing a side surface of the ground main body according to the embodiment of FIG.

FIG. 3 shows a ground structure according to the embodiment of FIG.
2A is an explanatory view showing an AA cross section of FIG. 2, and b is an BB cross section of FIG.

FIG. 4 is an explanatory view showing a cross section of a conventional low-pressure turbine.

FIG. 5 is a diagram illustrating a gland main body mounting portion of a conventional low-pressure turbine casing, in which a is a side surface, b is a BB cross section, and c is a CC cross section.

FIG. 6 is an explanatory view showing a side surface of a gland body of a conventional low-pressure turbine.

FIG. 7 shows a gland structure of a conventional low-pressure turbine,
6 is an explanatory view showing an AA cross section of FIG. 6 and b is a BB cross section of FIG.

[Explanation of symbols]

 4 Gland body 5 Feed port 6 Discharge port 9 Supply port 10 Gland body mounting part 15 Steam passage

Claims (1)

[Claims] 1. A gland main body mounting portion of a low pressure turbine casing is provided with a gland seal vapor feeding port supplied from the outside and a gland seal vapor feeding port supplied to the inside, at the lower part of the gland body mounting portion. A structure for mounting a gland main body in a turbine casing, characterized in that an annular steam passage is provided on the inner surface of the portion so as to surround the rotor about one round and to connect the feed port and the feed port.