Diaphragm for a steam turbine

Claim 2

A diaphragm of an axial flow turbine, said turbine including a rotor and energy extracting means coupled to said rotor for converting at least a portion of energy available from an elastic fluid into mechanical energy, said diaphragm for circumferential disposition around the rotor for directing said elastic fluid into said energy extracting means, comprising: a plurality of spaced apart nozzle partitions forming a respective plurality of channels therebetween; and an inner member for fixedly securing said plurality of nozzle partitions, each of said plurality of nozzle partitions having a root portion proximate the inner member and including a leading edge and a trailing edge and disposed to include both an axial lean and a tangential lean of the trailing edge, each of said axial lean and said tangential lean with respect to a radial reference from the axis of rotation of the rotor, said inner member including a greater outward radial extent proximate the leading edge of the nozzle partitions than the outward radial extent proximate the trailing edge of the nozzle partitions; each of said plurality of nozzle partitions spaced from an adjacent nozzle partition such that the channel therebetween includes a minimum throat and a trailing edge throat, wherein the minimum throat is disposed between the leading edge of the nozzle partition and the trailing edge throat at the root of the nozzle partition and the minimum throat is disposed monotonically more proximate the trailing edge throat of the nozzle partition at increasing radial distance from the root of said nozzle partition, whereby the margins of the channel define a converging-diverging passageway at least over a portion of the radial extent of the channel.

Claim 3

The diaphragm as in claim 1 wherein said axial lean is less than about 5 degrees.

Claim 4

The diaphragm as in claim 1 wherein said tangential lean is less than about 12 degrees.

Claim 5

The diaphragm as in claim 1 wherein said minimum throat merges with said trailing edge throat at a predetermined radial distance intermediate the tip and the root of the nozzle partition.

Claim 6

The diaphragm as in claim 1 wherein the outward radial extent of said inner member proximate the leading edge of the nozzle partitions to a predetermined axial location intermediate said minimum throat and said trailing edge throat at the root of the nozzle partitions defines an arc of a torus wherein the outward radial extent of said inner member is greater proximate the leading edge of the nozzle partitions than at said predetermined location point and wherein the outward radial extent of said inner member from said predetermined axial location to the portion of said inner member proximate the trailing edge of the nozzle partitions defines a truncated conical section.

Claim 7

An axial flow turbine including a rotor and energy extracting means coupled to said rotor for converting at least a portion of energy available from an elastic fluid into mechanical energy, comprising: a diaphragm for circumferential disposition around the rotor for directing at least a portion of said elastic fluid into said energy extracting means, said diaphragm including: a plurality of spaced apart nozzle partitions forming a respective plurality of channels therebetween; and an inner member for fixedly securing said plurality of nozzle partitions, each of said plurality of nozzle partitions having a root portion proximate the inner member and including a leading edge and a trailing edge and disposed to include both an axial lean and a tangential lean of the trailing edge, each of said axial lean and said tangential lean with respect to a radial reference from the axis of rotation of the rotor, said inner member including a greater outward radial extent proximate the leading edge of the nozzle partitions than the outward radial extent proximate the trailing edge of the nozzle partitions; each of said plurality of nozzle partitions spaced from an adjacent nozzle partition such that the channel therebetween includes a minimum throat and a trailing edge throat, wherein the minimum throat is disposed between the leading edge of the nozzle partition and the trailing edge throat at the root of the nozzle position and the minimum throat is disposed monotonically more proximate the trailing edge throat of the nozzle partition at increasing radial distance from the root of said nozzle partition, whereby the margins of the channel define a converging-diverging passageway at least over a portion of the radial extent of the channel.

Claim 8

An axial flow turbine including a rotor and energy extracting means coupled to said rotor for converting at least a portion of energy available from an elastic fluid into mechanical energy, comprising: a diaphragm for circumferential disposition around the rotor for directing at least a portion of said elastic fluid into said energy extracting means, said diaphragm including: a plurality of spaced apart nozzle partitions forming a respective plurality of channels therebetween; and an inner member for fixedly securing said plurality of nozzle partitions, each of said plurality of nozzle partitions having a root portion proximate the inner member and including a leading edge and a trailing edge and disposed to include both an axial lean and a tangential lean of the trailing edge, each of said axial lean and said tangential lean with respect to a radial reference from the axis of rotation of the rotor, said inner member including a greater outward radial extent proximate the leading edge of the nozzle partitions than the outward radial extent proximate the trailing edge of the nozzle partitions; each of said plurality of nozzle partitions spaced from an adjacent nozzle partition such that the channel therebetween includes a minimum throat and a trailing edge throat, wherein the minimum throat is disposed between the leading edge of the nozzle partition and the trailing edge throat at the root of the nozzle position and the minimum throat is disposed monotonically more proximate the trailing edge throat of the nozzle partition at increasing radial distance from the root of said nozzle partition, whereby the margins of the channel define a converging-diverging passageway at least over a portion of the radial extent of the channel.

Claim 9

The turbine as in claim 6 wherein said axial lean is less than about 5 degrees.

Claim 10

The turbine as in claim 6 wherein said tangential lean is less than about 12 degrees.

Claim 11

The turbine as in claim 6 wherein said minimum throat merges with said trailing edge throat at a predetermined radial distance intermediate the tip and the root of the nozzle partition.

Claim 12

The turbine as in claim 6 wherein the outward radial extent of said inner member proximate the leading edge of the nozzle partitions to a predetermined axial location intermediate said minimum throat and said trailing edge throat at the root of the nozzle partitions defines an arc of a torus wherein the outward radial extent of said inner member is greater proximate the leading edge of the nozzle partitions than at said predetermined axial location and wherein the outward radial extent of said inner member from said predetermined axial location to the portion of said inner member proximate the trailing edge of the nozzle partitions defines a truncated conical section.

Claim 13

The turbine as in claim 10 wherein said energy extracting means comprises a plurality of buckets, said buckets being circumferentially disposed around said rotor and being disposed axially downstream from said diaphragm, and an extension of the conical section intercepts said plurality of buckets at the intersection of the leading edge and root of the plurality of buckets.