Full arc admission steam turbine
View Patent ↗The invention relates to a full arc admission steam turbine, which includes a plurality of nozzle boxes for inducing steam, and a plurality of nozzle plates for bearing nozzles, one nozzle plate corresponding to each nozzle box. The steam turbine 100 further includes a plurality of spacer plates corresponding to the plurality of nozzle boxes, wherein the spacer plate is disposed between the nozzle plate and the nozzle box, by which a flow path is formed between the plurality of nozzle boxes and the plurality of the nozzle plates through the plurality of spacer plates to achieve a full arc admission. With the solution according to embodiments of the present invention, existing partial arc steam turbine may be easily converted to be a full arc admission steam turbine. This will reduce cost of equipment upgrading. Outage due to onsite conversion may be significantly reduced.
1. A full arc admission steam turbine comprising a plurality of nozzle boxes for inducing steam, and a plurality of nozzle plates for bearing nozzles, one nozzle plate corresponding to each nozzle box, the steam turbine further comprises a plurality of spacer plates corresponding to the plurality of nozzle boxes, wherein the spacer plate is disposed between the nozzle plate and the nozzle box, by which a flow path is formed between the plurality of nozzle boxes and the plurality of the nozzle plates through the plurality of spacer plates to achieve a full arc admission wherein the spacer plate is configured to be part of a circle, and the spacer plate comprise an outer ring, an inner ring separated from the inner ring by a communication space formed as part of the flow path, and two link portions disposed at opposite leading and trailing ends of the outer ring and the inner ring to connect the outer ring and the inner ring, characterised by the link portion having a less length in an axial direction of the steam turbine than that of the outer ring and the inner ring such that the flow path communicates with two adjacent communication spaces.
2. The full arc admission steam turbine according to claim 1 wherein two adjacent spacer plates are assembled in a head-to-toe manner, the link portion on the leading end of one of the two adjacent spacer plates rests against the link portion on the trailing end of the other of the two adjacent spacer plates.
3. The full arc admission steam turbine according of claim 1 wherein the plurality of the spacer plates are assembled in a head-to-toe manner, the flow path comprises a complete ring shape part around the axial direction of the steam turbine that is formed by the plurality of the spacer plates.
4. The full arc admission steam turbine according to claim 1 wherein two series of fastener holes are disposed on the inner ring and the outer ring of the spacer plate, wherein one series of the two series of fastener holes is used to connect the spacer plate to the nozzle box, respectively, and the other series of the two series of fastener holes is used to connect the nozzle plate to the spacer plate, respectively.
5. The full arc admission steam turbine according to claim 1 wherein, one series of fastener holes are disposed on the inner ring, or the outer ring, or both, of the spacer plate so as to be used to connect the nozzle plate, the spacer plate and the nozzle box together.
6. The full arc admission steam turbine according to claim 1 wherein the spacer plate comprises on its leading end a protrusion and a recess on its trailing end, where, when two adjacent spacer plates are assembled, the protrusion on the leading end of one of the two spacer plates engage with the recess on the trailing end of the other of the two spacer plates.
7. The full arc admission steam turbine according to claim 1 wherein the recess on the trailing end of the spacer plate consists of peripheral walls around the trailing end of the spacer plate, leaving an open side facing the nozzle plate when assembled.
8. The full arc admission steam turbine according to claim 1 wherein the spacer plate is shaped to be a semi-circle, a quadrant of a circle, one sixth of a circle, or one eighth of a circle.