IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0470474
(1990-01-26)
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발명자
/ 주소 |
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출원인 / 주소 |
- Westinghouse Electric Corp.
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대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
7 인용 특허 :
5 |
초록
▼
An axial flow steam turbine has a self-locking nozzle block wherein the nozzle block has radially inwardly and outwardly extending flanges that seat in grooves formed in spaced shrouds of the nozzle ring, with locking pins provided, in bores in a rear arcuate section of the nozzle ring, formed from
An axial flow steam turbine has a self-locking nozzle block wherein the nozzle block has radially inwardly and outwardly extending flanges that seat in grooves formed in spaced shrouds of the nozzle ring, with locking pins provided, in bores in a rear arcuate section of the nozzle ring, formed from the material that has a thermal coefficient of expansion greater than the thermal coefficient of expansion of the material from which the nozzle ring is formed. Preferably, the nozzle block is formed from a material having a thermal coefficient of expansion comparable to that of the pins. Steam passing through the turbine heats its assembly such that the locking pins force the flanges of the nozzle block into sealing contact with a first arcuate section of the nozzle ring so as to prevent vibration and loosening of the nozzle block in the nozzle ring.
대표청구항
▼
1. An axial flow steam turbine comprising: a rotor; a casing; an inlet nozzle ring disposed circumferentially about said rotor within said casing, having a first thermal coefficient of expansion, said inlet nozzle ring including radially spaced inner and outer shrouds, said shrouds having confr
1. An axial flow steam turbine comprising: a rotor; a casing; an inlet nozzle ring disposed circumferentially about said rotor within said casing, having a first thermal coefficient of expansion, said inlet nozzle ring including radially spaced inner and outer shrouds, said shrouds having confronting grooves formed therein, forming front and rear arcuate sections having confronting faces, and a plurality of nozzle chambers communicating with said space; a plurality of nozzle blocks, having a second thermal coefficient of expansion greater than the first coefficient of expansion of the inlet nozzle ring, and having radially inwardly and outwardly extending flanges, said flanges positioned in said confronting grooves between said front and rear arcuate sections of said inlet nozzle ring; a plurality of apertures formed through the front arcuate section of said nozzle ring; coaxial bores formed in the rear arcuate section thereof to form an end wall; and a locking pin, having a thermal coefficient of expansion greater than the first coefficient of expansion of the inlet nozzle ring, inserted into the bore in the rear arcuate section having a first end contacting said end wall, and a second end flush with said face of said rear arcuate section at ambient temperature. 2. An axial flow steam turbine as defined in claim 1, wherein said second coefficient of expansion is at 1.5×10 -6 in./in./°F. greater than said first coefficient of expansion. 3. An axial flow steam turbine as defined in claim 2, wherein said plurality of pins are spaced apart about said nozzle ring at intervals of about 5° apart. 4. An axial flow steam turbine as defined in claim 2, wherein said inlet nozzle ring comprises a steel alloy containing 2.25% by weight chromium and 1% molybdenum; said nozzle block comprises 316 stainless steel alloy, and said pins comprise A286 stainless steel alloy. 5. An axial flow steam turbine as defined in claim 2, wherein the thermal coefficient of expansion of the nozzle block is comparable to the thermal coefficient of expansion of the locking pin. 6. An axial flow steam turbine comprising: a rotor; a casing; an inlet nozzle ring disposed circumferentially about said rotor within said casing, having a first thermal coefficient of expansion, said inlet nozzle ring including radially spaced inner and outer shrouds, said shrouds having confronting grooves formed therein, forming front and rear arcuate sections having confronting faces, and a plurality of nozzle chambers communicating with said space; a plurality of nozzle blocks, having a second thermal coefficient of expansion at least 1.5×10 -6 in./in./°F. greater than the first coefficient of expansion of the inlet nozzle ring, and having radially inwardly and outwardly extending flanges, said flanges positioned in said confronting grooves between said front and rear arcuate sections of said inlet nozzle ring; a plurality of apertures formed through the front arcuate section of said nozzle ring; coaxial bores formed in the rear arcuate section thereof to form an end wall; and a locking pin, having a thermal coefficient of expansion comparable to the coefficient of expansion of the nozzle blocks, inserted into the bore in the rear arcuate section having a first end contacting said end wall, and a second end flush with said face of said rear arcuate section at ambient temperature. 7. An axial flow steam turbine as defined in claim 6, wherein said inlet nozzle ring comprises a steel alloy containing 2.25% by weight chromium and 1% molybdenum; said nozzle block comprises 316 stainless stell alloy, and said pins comprise A286 stainless steel alloy. 8. A method of locking a nozzle block in an inlet nozzle ring of an axial flow steam turbine, wherein said turbine has a rotor, a casing, and the inlet nozzle ring circumferentially disposed about the rotor within the casing, the inlet nozzle ring including radially spaced inner and outer shrouds having confronting grooves therein forming front and rear arcuate sections having confronting faces, one of which is a forwardly facing face of the rear arcuate section, and a plurality of nozzle chambers communicating with said space, comprising: forming apertures through the front arcuate section of said nozzle ring; forming coaxial bores into the rear arcuate section thereof to form an end wall; providing a pin having a thermal coefficient of expansion greater than the thermal coefficient of expansion of said nozzle ring; inserting a said pin through the aperture in the front arcuate section and into the bore in the rear arcuate section into contact with said end wall, with a portion of said pin extending outwardly from the forwardly facing face of the rear arcuate section into said grooves; machining said forwardly facing face and said portion of said pin to form a finished surface with the pinflush with the forwardly facing face; and inserting a nozzle block having radially inwardly and outwardly extending flanges into said nozzle ring with said flanges seated in said grooves. 9. The method of locking a nozzle block in an inlet nozzle ring of an axial flow steam turbine as defined in claim 8, wherein the thermal coefficient of expansion of said pin is at least 1.5 ×10 -6 in./in./°F. greater than the thermal coefficient of expansion of said nozzle ring. 10. The method of locking a nozzle block in an inlet nozzle ring of an axial flow steam turbine as defined in claim 9, wherein the thermal coefficient of expansion of said nozzle block is comparable to the thermal coefficient of expansion of said pin.
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