Patent Application
20100196167
The invention relates generally to turbine technology. More particularly, the invention relates to a cover member defining a rotor chamber in a turbine.
In turbines, gas or steam impinges on rotating blades that are coupled to a rotating shaft so as to cause the rotating shaft to turn. A cooling gas stream is directed through holes in the rotating blades to prevent overheating of the rotating blades. Ideally, the holes are as small as possible to increase cooling efficiencies. These smaller holes are more susceptible to being blocked by particles.
A first aspect of the disclosure provides an apparatus comprising: a cover member defining a rotor chamber adjacent to a rotor wheel that supports a rotating blade in a turbine, the cover member including: a first aperture for introducing a cooling gas stream into the rotor chamber, and a second aperture positioned in a radially outward portion of the cover member for allowing a portion of the cooling gas stream to exit the rotor chamber.
A second aspect of the disclosure provides a turbine comprising: a plurality of rotating blades, each rotating blade coupled to a rotating shaft by a rotor wheel; and a cover member defining a rotor chamber adjacent to each rotor wheel, the cover member including: a first aperture for introducing a cooling gas stream into the rotor chamber, and a second aperture positioned in a radially outward portion of the cover member for allowing a portion of the cooling gas stream to exit the rotor chamber.
A third aspect of the disclosure provides a method comprising: introducing a cooling gas stream to a rotor chamber defined by a cover member adjacent to a rotor wheel that supports a rotating blade in a turbine; allowing a portion of the cooling gas stream to exit the rotor chamber through an aperture in a radially outward portion of the cover member; and directing a remainder of the cooling gas stream to cool the rotating blade.
Referring to the drawings,
In operation, gas or steam 24 enters an inlet 26 of turbine 10 and is channeled through stationary vanes 22. Vanes 22 direct gas or steam 24 downstream against blades 20. Gas or steam 24 passes through the remaining stages imparting a force on blades 20 causing shaft 14 to rotate. At least one end of turbine 10 may extend axially away from rotating shaft 12 and may be attached to a load or machinery (not shown) such as, but not limited to, a generator, and/or another turbine.
In one embodiment, turbine 10 may include five stages. The five stages are referred to as L0, L1, L2, L3 and L4. Stage L4 is the first stage and is the smallest (in a radial direction) of the five stages. Stage L3 is the second stage and is the next stage in an axial direction. Stage L2 is the third stage and is shown in the middle of the five stages. Stage L1 is the fourth and next-to-last stage. Stage L0 is the last stage and is the largest (in a radial direction). It is to be understood that five stages are shown as one example only, and each turbine may have more or less than five stages. Also, as will be described herein, the teachings of the invention do not require a multiple stage turbine.
A cooling gas stream 110 is directed through another path 120 in a support ring 122, which may be part of a nozzle or casing of the stage to which cover member 100 belongs. An outer extremity of cover member 100 may be sealed against support ring 122 by a seal 128, e.g., a labyrinth seal. Cooling gas stream 110 may be generated, for example, from a compressor (not shown) and may include, for example, air or other gases and dust.
Referring to
In an alternative embodiment, shown in
While cover member 100 has been illustrated as a separate structure from rotor wheel 18 and rotating blade 20, it is understood that cover member 100 or a portion thereof including aperture 142 for dirt separation may be formed as part of rotating blade 20, rotor wheel 18 and/or other structure. For example, radially outward portion 140 of cover member 100 may be formed as an integral part of rotor wheel 18 rather than as part of a separate section 100 supported by arm 132. Seals would be provided to seal rotor wheel 18 with the remaining structure of cover member 100 and/or support ring 122, as necessary. Consequently, the term “cover member” should be given a broad interpretation within the scope of the invention as any feature defining rotor chamber 102 adjacent rotor wheel 18.
The terms “first,” “second,” and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another, and the terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. The modifier “about” used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context, (e.g., includes the degree of error associated with measurement of the particular quantity). The suffix “(s)” as used herein is intended to include both the singular and the plural of the term that it modifies, thereby including one or more of that term (e.g., the metal(s) includes one or more metals). Ranges disclosed herein are inclusive and independently combinable (e.g., ranges of “up to about 25 wt %, or, more specifically, about 5 wt % to about 20 wt %”, is inclusive of the endpoints and all intermediate values of the ranges of “about 5 wt % to about 25 wt %,” etc).
While various embodiments are described herein, it will be appreciated from the specification that various combinations of elements, variations or improvements therein may be made by those skilled in the art, and are within the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
