METHOD AND PURGE APPARATUS FOR PREVENTING DEFORMATION OF CHAMBER OF GAS TURBINE, AND GAS TURBINE PROVIDING PURGE APPARATUS

• US 20130251501A1
• Filed: 11/02/2012
• Published: 09/26/2013
• Est. Priority Date: 03/26/2012
• Status: Active Grant

• Current Assignee: Mitsubishi Power Limited (Mitsubishi Heavy Industries, Ltd.)
• Original Assignee: Mitsubishi Heavy Industries, Ltd.
• Inventors: Araki, Masato, Iwasaki, Yoshifumi
• Granted Patent: US 9,624,788 B2
• Time in Patent Office: Days
• US Class Current: 415/1
• CPC Class Codes: F01D 21/00 Shutting-down of machines or engines, e.g. in emergency; Regulating, controlling, or safety means not otherwise provided for
• CPC Class Codes: F01D 25/24 Casings modified for heating or cooling F01D25/14; Casing parts, e.g. diaphragms, casing fastenings casings for rotary machines or engines in general F16M ; special arrangements in stators dealing with breaking-off of part of rotor F01D21/045
• CPC Class Codes: F02C 7/18 the medium being gaseous, e.g. air F02C7/125 takes precedence

Abstract

In this method of preventing deformation in a turbine casing of a gas turbine, in a turbine casing 10 there is arranged a buffer tank 30. In this buffer tank 30 there are formed a stagnation part agitation air opening 52 which ejects part of the air from an air compressor 21 as stagnation part agitation air Ga2 toward a stagnation part 19 within the turbine casing, and an overall agitation air opening 51 which ejects overall agitation air Ga1 for agitating gas held in an upper space within the turbine casing. In the buffer tank 30 there is provided a partition wall 36 with through holes 53 formed therein serving to resist air from the air compressor 21, in order to make the ejection speed of the overall agitation air lower than the ejection speed of the stagnation part agitation air.

Claims

1. A purging device which ejects air into a turbine casing of a gas turbine to prevent deformation in this turbine casing when the gas turbine is in a stop state, the purging device comprising:

an air supply source which supplies the air;

a stagnation part agitation air ejecting part with a stagnation part agitation air opening formed therein through which part of the air is ejected as stagnation part agitation air toward a stagnation part where gas flow stagnates in the turbine casing;

an overall agitation air ejecting part with an overall agitation air opening formed therein, through which part of the air is ejected as overall agitation air toward a portion in the turbine casing different from the stagnation part, to agitate gas held in an upper space of this turbine casing; and

an ejection speed adjusting device which makes an ejection speed of the overall agitation air from the overall agitation air opening, lower than an ejection speed of the stagnation part agitation air from the stagnation part agitation air opening.

2. A purging device according to claim 1, wherein the ejection speed adjusting device has a pressure adjusting mechanism which makes the pressure of the air from the air supply source just before reaching the overall agitation air opening, lower than the pressure of the air from the air supply source just before reaching the stagnation part agitation air opening.

3. A purging device according to claim 2, wherein the pressure adjusting mechanism has an orifice which is arranged immediately before the overall agitation air opening and in which there is formed a through hole for allowing the air from the air supply source to travel therethrough.

4. A purging device according to claim 1, wherein the ejection speed adjusting device has a mesh structure body which is provided on the overall agitation air opening and in which there are formed a number of openings each having an area smaller than the opening area of the overall agitation air opening.

5. A purging device according to claim 1, wherein:

there is provided a buffer tank;

in the buffer tank, in the interior thereof, there is formed an air chamber into which the air from the air supply source flows, and there are formed the overall agitation air opening and the stagnation part agitation air opening; and

the ejection speed adjusting device is provided in the buffer tank.

6. A purging device according to claim 1, wherein:

there are provided a primary line for allowing air from the air supply source to travel therethrough, an overall agitation air line which branches from this primary line and communicates with the overall agitation air opening, and a stagnation part agitation air line which branches from this primary line and communicates with the stagnation part agitation air opening; and

the pressure adjusting mechanism is provided on the overall agitation air line.

7. A purging device according to claim 1, wherein the air supply source has a stagnation part agitation air supply source which supplies, to the stagnation part agitation air opening, the air serving as the stagnation part agitation air, and an overall agitation air supply source which supplies, to the overall agitation air opening, air which is the air serving as the overall agitation air and which is of a pressure lower than that of the air supplied from the stagnation part agitation air supply source.

8. A gas turbine which is provided with a purging device according to claim 1, and the turbine casing.

9. A gas turbine provided with a purging device according to claim 5, and the turbine casing, wherein:

in an upper part of the turbine casing there is formed a manhole, and this manhole is blocked by a manhole lid; and

the buffer tank is fixed on the turbine casing inner side of the manhole lid.

10. A method of preventing deformation in a turbine casing of a gas turbine, wherein there are included:

a gas turbine stopping step of stopping fuel supply to the gas turbine; and

an air ejecting step of ejecting stagnation part agitation air toward a stagnation part where gas flow within the turbine casing stagnates to thereby agitate gas within this stagnation part, and ejecting overall agitation air toward a portion different from this stagnation part within this turbine casing, at an ejection speed lower than that of this stagnation part agitation air to thereby agitate air being held in an upper space within this turbine casing.