. Applied thermodynamics for engineers. Fig. 262. Art. 537. — Curtis Turbine. 390 APPLIED THERMODYNAMICS by automatically varying the number of nozzles in use for admitting steam to thefirst stage. A step bearing carries the whole weight of the machine, and must besupplied with lubricant under heavy pressure; an hydraulic accumulator system iscommonly employed. 538. Rateau Turbine. This is a horizontal, axial flow, multi-stage impulseturbine. The number of pressure stages is very large — from twenty-five is one velocity stage in each pressure stage. Yery low speeds are, therefore,
. Applied thermodynamics for engineers. Fig. 262. Art. 537. — Curtis Turbine. 390 APPLIED THERMODYNAMICS by automatically varying the number of nozzles in use for admitting steam to thefirst stage. A step bearing carries the whole weight of the machine, and must besupplied with lubricant under heavy pressure; an hydraulic accumulator system iscommonly employed. 538. Rateau Turbine. This is a horizontal, axial flow, multi-stage impulseturbine. The number of pressure stages is very large — from twenty-five is one velocity stage in each pressure stage. Yery low speeds are, therefore,possible. Figure 263 shows the general arrangement; the trarwerse partitions e, eform cells, in w^hich revolve the wheels/, /: the nozzles are merely slots in thepartitions. The blades are pressed out of sheet steel and riveted to the wheels themselves are of thin pressed Fig. 20,3. Art. 538. -Rateau Turbine. 539. Westinghouse-Parsons Turbine. This is of the axial flow pressure type,and horizontal. The steam expands through a large number of successive fixedand moving blades. In Fig. 264, the steam enters at A and passes along the vari-ous blades toward the left; the movable buckets are mounted on the three drums,and the fixed buckets project inward from the casings. The diameters of thedrums increase by steps; the increasing volume of the steam within any section isaccommodated by varying the bucket heights. Tlie balance pistons P, P, P areused to counteract end thrust. The speed is fairly high, and special provisionmust be made for it in the design of the bearings. Governing is effected by inter-^mittently opening the valve T; this valve is wide open whenever open at all. The length of this machine is sometimes too great for convenience. To over-come this, the double-flow turbine receives steam near its center, throughexpanding nozzles which supply-
Size: 2107px × 1186px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublishernewyo, bookyear1913
