The present disclosure is directed to, generally, a steam turbine and, more particularly, to a casing for a steam turbine.
Turbomachines, such as steam turbines, gas turbines, centrifugal flow compressors, and axial flow compressors, may be utilized in various industries. Turbines, in particular, have a widespread use in power stations, jet engine applications, gas turbines, and automotive applications. Steam turbines and centrifugal flow compressors are also commonly used in large-scale industrial applications, such as ethylene plants, oil refineries, and power generation.
Steam turbines are devices that extract thermal energy from pressurized steam and use it to conduct mechanical work on a rotating output shaft. Multi-stage steam turbines are well known in the art. A typical multi-stage steam turbine includes a turbine casing that accommodates a series of diaphragms and a rotor in the form of a shaft with blades. The main purpose of the casing is to contain the high internal pressure in the turbine. Many steam turbines have a casing with a circular cross-sectional shape. A steam turbine casing must contain high internal pressure and risk experiencing leakage that can lead to explosive and dangerous results.
In view of the foregoing, there is a current need for a steam turbine that includes a casing design that enhances the steam turbine's ability to seal a split line flange to contain internal pressures in the steam turbine. There is also a current need for a steam turbine that includes a casing design that increases lateral forces on the casing to create a stronger seal at a split line in a flange of the steam turbine.
In one example of the present disclosure, a steam turbine may include a casing defining an interior cavity, wherein the casing comprises a first casing half and a second casing half, which are connected to one another to form the casing, wherein an interior surface of the first casing half has a first portion with a first curvature and a second portion with a second curvature, wherein the first curvature and the second curvature are different, and wherein an interior surface of the second casing half has a first portion with a first curvature and a second portion with a second curvature, wherein the first curvature and the second curvature are different.
In another example of the present disclosure, the first casing half and the second casing half may be connected at a split line. The first casing half and the second casing half may be mechanically connected to one another. At the split line, an internal pressure causes edges of each of the first casing half and the second casing half to rotate towards one another to create a seal. The first and second casing halves each may have an inner surface including at least one flat portion and a substantially curved portion. The first and second casing halves may be separable from one another when not connected to one another. The first and second casing halves each may have an inner surface including a first flat portion, a second flat portion, and a substantially curved portion. The substantially curved portion of the first and second casing halves may be positioned between the first flat portion and the second flat portion. The first flat portions and the second flat portions of the first and second casing halves each may have a length ranging from 0.1 inches to 3 inches. The inner surfaces of the first casing half and the second casing half may form a substantially oval-shaped cross section.
In another example of the present disclosure, a steam turbine may include a casing defining an interior cavity. The casing may include a first casing half and a second casing half, which are connected to one another to form the casing. The first and second casing halves each may have an inner surface including at least one flat portion and a substantially curved portion.
In another example of the present disclosure, the first casing half and the second casing half may be connected at a split line. The first casing half and the second casing half may be mechanically connected to one another. At the split line, internal pressure may cause edges of each of the first casing half and the second casing half to rotate towards one another to create a seal. The first and second casing halves may be separable from one another when not connected to one another. The at least one flat portion of the first and second casing halves may include a first flat portion and a second flat portion. The substantially curved portion of the first and second casing halves may be positioned between the first flat portion and the second flat portion. The first flat portions and the second flat portions of the first and second casing halves each may have a length ranging from 0.1 inches to 3 inches. The inner surfaces of the first casing half and the second casing half may form a substantially oval-shaped cross section. The inner surfaces of the first and second casing halves may have corresponding shapes.
The present invention is also disclosed in the following clauses.
Clause 1: A steam turbine, comprising: a casing defining an interior cavity, wherein the casing comprises a first casing half and a second casing half, which are connected to one another to form the casing, wherein an interior surface of the first casing half has a first portion with a first curvature and a second portion with a second curvature, wherein the first curvature and the second curvature are different, and wherein an interior surface of the second casing half has a first portion with a first curvature and a second portion with a second curvature, wherein the first curvature and the second curvature are different.
Clause 2: The steam turbine of Clause 1, wherein the first casing half and the second casing half are connected at a split line.
Clause 3: The steam turbine of Clause 1 or 2, wherein the first casing half and the second casing half are mechanically connected to one another.
Clause 4: The steam turbine of Clause 2, wherein, at the split line, an internal pressure causes flat edges of each of the first casing half and the second casing half to rotate towards one another to create a seal.
Clause 5: The steam turbine of any of Clauses 1-4, wherein the inner surfaces of the first casing half and the second casing half comprise at least one flat portion and a substantially curved portion.
Clause 6: The steam turbine of any of Clauses 1-5, wherein the first and second casing halves are separable from one another when not connected to one another.
Clause 7: The steam turbine of any of Clauses 1-6, wherein the inner surfaces of the first casing half and the second casing half comprise a first flat portion, a second flat portion, and a substantially curved portion.
Clause 8: The steam turbine of Clause 7, wherein the substantially curved portion of the first and second casing halves is positioned between the first flat portion and the second flat portion.
Clause 9: The steam turbine of Clause 7 or 8, wherein the first flat portions and the second flat portions of the first and second casing halves each have a length ranging from 0.1 inches to 3 inches.
Clause 10: The steam turbine of any of Clauses 1-9, wherein the inner surfaces of the first casing half and the second casing half form a substantially oval-shaped cross section.
Clause 11: A steam turbine, comprising: a casing defining an interior cavity, wherein the casing comprises a first casing half and a second casing half, which are connected to one another to form the casing, and wherein the first and second casing halves each have an inner surface comprising at least one flat portion and a substantially curved portion.
Clause 12: The steam turbine of Clause 11, wherein the first casing half and the second casing half are connected at a split line.
Clause 13: The steam turbine of Clause 11 or 12, wherein the first casing half and the second casing half are mechanically connected to one another.
Clause 14: The steam turbine of Clause 12, wherein, at the split line, internal pressure causes flat edges of each of the first casing half and the second casing half to rotate towards one another to create a seal.
Clause 15: The steam turbine of any of Clauses 11-14, wherein the first and second casing halves are separable from one another when not connected to one another.
Clause 16: The steam turbine of any of Clauses 11-15, wherein the at least one flat portion of the first and second casing halves comprises a first flat portion and a second flat portion.
Clause 17: The steam turbine of Clause 16, wherein the substantially curved portion of the first and second casing halves is positioned between the first flat portion and the second flat portion.
Clause 18: The steam turbine of Clause 16 or 17, wherein the first flat portions and the second flat portions of the first and second casing halves each have a length ranging from 0.1 inches to 3 inches.
Clause 19: The steam turbine of any of Clauses 11-18, wherein the inner surfaces of the first casing half and the second casing half form a substantially oval-shaped cross section.
Clause 20: The steam turbine of any of Clauses 11-19, wherein the inner surfaces of the first and second casing halves have corresponding shapes.
For purposes of the description hereinafter, spatial orientation terms, as used, shall relate to the referenced embodiment as it is oriented in the accompanying drawings, figures, or otherwise described in the following detailed description. However, it is to be understood that the embodiments described hereinafter may assume many alternative variations and configurations. It is also to be understood that the specific components, devices, features, and operational sequences illustrated in the accompanying drawings, figures, or otherwise described herein are simply examples and should not be considered as limiting.
The present disclosure is directed to, in general, a steam turbine and, more particularly, a casing design for a steam turbine. Certain preferred and non-limiting aspects of the components of the system are illustrated in
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While several aspects of the steam turbine 2 are shown in the accompanying figures and described in detail hereinabove, other aspects will be apparent to, and readily made by, those skilled in the art without departing from the scope and spirit of the disclosure. Accordingly, the foregoing description is intended to be illustrative rather than restrictive. The invention described hereinabove is defined by the appended claims and all changes to the invention that fall within the meaning and range of equivalency of the claims are to be embraced within their scope.