Patent Description:
In view of the foregoing, conventional multistage compressors may often include intercoolers (e.g., external heat exchangers) configured to extract heat or thermal energy from the process fluid flowing therethrough to thereby maintain the process fluid at a substantially constant temperature during compression. Utilizing the intercoolers, however, may increase the relative size and complexity of the multistage compressors, as additional components (e.g., piping) may often be necessary to couple the intercoolers with the compressor stages. Further, the increased complexity of the multistage compressors may correspondingly increase the overall cost associated with maintaining, servicing, and/or repairing the multistage compressors.

<CIT> discloses a compressor with an internally cooled diaphragm according to the preamble of independent claim <NUM>.

What is needed, then, is an improved system for cooling a process fluid in a compressor.

Embodiments of the disclosure provides an internally-cooled diaphragm for a compressor according to any of claims <NUM> to <NUM>.

Embodiments of the disclosure also provides an internally-cooled compressor according to any of claims <NUM> to <NUM>. The present disclosure is best understood from the following detailed description when read with the accompanying Figures.

It is to be understood that the following disclosure describes several exemplary embodiments for implementing different features, structures, or functions of the invention. Exemplary embodiments of components, arrangements, and configurations are described below to simplify the present disclosure; however, these exemplary embodiments are provided merely as examples and are not intended to limit the scope of the invention which is defined by the appended claims.

Additionally, the present disclosure may repeat reference numerals and/or letters in the various exemplary embodiments and across the Figures provided herein. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various exemplary embodiments and/or configurations discussed in the various Figures.

<FIG> illustrates a cutaway, cross-sectional view of a compressor <NUM> including an internally-cooled diaphragm <NUM>, according to one or more embodiments. <FIG> illustrates an enlarged view of the compressor <NUM> indicated by the box labeled "1B" of <FIG>, according to one or more embodiments. As illustrated in <FIG> and <FIG>, the compressor <NUM> may be a centrifugal compressor. Illustrative centrifugal compressors may include, but are not limited to, straight-thru centrifugal compressors, single-stage overhung centrifugal compressors, multistage overhung centrifugal compressors, back-to-back centrifugal compressors, or the like. The compressor <NUM> may include a casing <NUM> and one or more compressor stages (one is shown <NUM>) configured to compress or pressurize a process fluid introduced thereto. For simplicity, <FIG> and <FIG> illustrate a single compressor stage <NUM> of the compressor <NUM>; however, it should be appreciated that the compressor <NUM> may include multiple compressor stages without departing from the scope of the disclosure. For example, the compressor <NUM> may include a first compressor stage, a final compressor stage, and one or more intermediate compressor stages disposed between the first and final compressor stages. As illustrated in <FIG> and <FIG>, the compressor stage <NUM> includes an impeller <NUM> having an inlet, such as an impeller inlet <NUM>, and an outlet, such as an impeller outlet <NUM>. The impeller <NUM> may include a center portion or hub <NUM> and a plurality of blades <NUM> (see <FIG>) extending from the hub <NUM>. The hub <NUM> of the impeller <NUM> may be coupled with a rotary shaft <NUM> configured to rotate the impeller <NUM> about an axis <NUM> (e.g., longitudinal axis) of the compressor <NUM>.

As illustrated in <FIG>, the internally-cooled diaphragm <NUM> is disposed and/or hermetically sealed in the casing <NUM>. The casing <NUM> and/or the internally-cooled diaphragm <NUM> at least partially defines a fluid pathway <NUM> extending through the compressor <NUM> through which the process fluid may flow. For example, the internally-cooled diaphragm <NUM> defines at least a portion of the fluid pathway <NUM> extending through the compressor stage <NUM> of the compressor <NUM>. The fluid pathway <NUM> may include an impeller cavity <NUM>, a diffuser <NUM> fluidly coupled with and extending radially outward from the impeller cavity <NUM>, a return bend <NUM> fluidly coupled with the diffuser <NUM>, and a return channel <NUM> fluidly coupled with and extending radially inward from the return bend <NUM>.

The impeller cavity <NUM> may be configured to receive the impeller <NUM>. The diffuser <NUM> is fluidly coupled with and extend radially outward from the impeller cavity <NUM>. As further described herein, the diffuser <NUM> is configured to receive the process fluid from the impeller <NUM> and convert kinetic energy (e.g., flow or velocity) of the process fluid from the impeller <NUM> to potential energy (e.g., increased static pressure). A plurality of diffuser vanes (one is shown <NUM>) is disposed in the diffuser <NUM> and configured to direct the flow of the process fluid through the diffuser <NUM> and/or decrease the velocity of the process fluid flowing through the diffuser <NUM>. The return bend <NUM> may be configured to receive the process fluid from the diffuser <NUM> and divert or turn the flow of the process fluid radially inward toward the return channel <NUM>.

As illustrated in <FIG>, the return channel <NUM> includes a plurality of return passages (five are shown <NUM>) extending radially inward from the return bend <NUM> toward the rotary shaft <NUM>. Each of the return passages <NUM> may include a diffusion region <NUM> disposed proximal an outer circumference of the internally-cooled diaphragm <NUM>, and a de-swirling region <NUM> disposed radially inward from the diffusion region <NUM>. At least one return channel vane <NUM> may be disposed in each of the de-swirling regions <NUM>. As further described herein, the internally-cooled diaphragm <NUM> is configured to separate or divide the flow of the process fluid from the return bend <NUM> and direct the separated flow into each of the return passages <NUM> of the return channel <NUM>. The internally-cooled diaphragm <NUM> further is configured to at least partially diffuse the flow of the process fluid through the respective diffusion regions <NUM> of the return passages <NUM>, and de-swirl the flow of the process fluid in the respective de-swirling regions <NUM> of the return passages <NUM>.

The casing <NUM> and/or the internally-cooled diaphragm <NUM> also at least partially defines a cooling pathway <NUM> through which a coolant or cooling fluid may flow. The cooling pathway <NUM> may be disposed near or proximal at least a portion of the fluid pathway <NUM>. For example, the cooling pathway <NUM> may be disposed proximal at least a portion of the diffuser <NUM> and/or at least a portion of the return channel <NUM> of the fluid pathway <NUM>. As further described herein, the cooling pathway <NUM> is in thermal communication with the fluid pathway <NUM>, and the cooling fluid flowing through the cooling pathway <NUM> is configured to absorb (e.g., indirectly) heat from a process fluid flowing through the fluid pathway <NUM>.

In an exemplary embodiment, the casing <NUM> and/or the internally-cooled diaphragm <NUM> at least partially defines a cooling fluid source and/or a cooling fluid drain fluidly coupled with the cooling pathway <NUM>. For example, as illustrated in <FIG>, the casing <NUM> may define a plenum <NUM> configured to deliver the cooling fluid to or receive the cooling fluid from the cooling pathway <NUM>. As further illustrated in <FIG>, the diffuser vanes <NUM> may at least partially define one or more conduits (one is shown <NUM>) extending therethrough and configured to provide fluid communication between the plenum <NUM> and the cooling pathway <NUM>. In another embodiment, the compressor <NUM> may include an external cooling fluid source (not shown) and/or an external cooling fluid drain (not shown). The external cooling fluid source and the external cooling fluid drain may be configured to deliver the cooling fluid to the cooling pathway <NUM> and receive the cooling fluid from the cooling pathway <NUM>, respectively. In at least one embodiment, the external cooling fluid source and/or the external cooling fluid drain may be fluidly coupled with the cooling pathway <NUM> via a head <NUM> (see <FIG>) of the compressor <NUM>. For example, the head <NUM> of the compressor <NUM> may at least partially define a flowpath (not shown) extending axially therethrough and configured to provide fluid communication between the cooling pathway <NUM> and the external cooling fluid source and/or the external cooling fluid drain. In another embodiment, the external cooling fluid source and/or the external cooling fluid drain may be fluidly coupled with the cooling pathway <NUM> via the casing <NUM>. For example, the casing <NUM> may define a flowpath (not shown) extending radially therethrough and configured to provide fluid communication between the cooling pathway <NUM> and the external cooling fluid source and/or the external cooling fluid drain.

The internally-cooled diaphragm <NUM> generally is an annular body. The internally-cooled diaphragm <NUM> is formed from separate components or pieces coupled with one another. For example, as illustrated in <FIG> and further illustrated in detail in <FIG> and <FIG>, the internally-cooled diaphragm <NUM> is formed from a stack of annular plates or disks <NUM>. The stack of plates <NUM> defines at least a portion of the fluid pathway <NUM> and the cooling pathway <NUM>. The stack of plates <NUM> at least partially defines the return passages <NUM> of the fluid pathway <NUM>. The stack of plates <NUM> also defines respective portions of the cooling pathway <NUM> in thermal communication with the return channel <NUM>.

As illustrated in <FIG> and <FIG>, the stack of plates <NUM> may include one or more end plates (two are shown <NUM>), one or more cooling fluid plates (four are shown <NUM>), and/or one or more process fluid plates (four are shown <NUM>). As further described herein, the process fluid plates <NUM>, the cooling fluid plates <NUM>, and/or the end plates <NUM> least partially define the fluid pathway <NUM> and/or the cooling pathway <NUM>. The process fluid plates <NUM>, the cooling fluid plates <NUM>, and/or the end plates <NUM> may be annular plates (e.g., annular, metal-based plates), and may be fabricated using one or more milling or etching processes or techniques. For example, the process fluid plates <NUM>, the cooling fluid plates <NUM>, and/or the end plates <NUM> may be fabricated via a mechanical milling process or a water jet technique. The process fluid plates <NUM>, the cooling fluid plates <NUM>, and/or the end plates <NUM> may be bonded, welded, brazed, or otherwise coupled with one another to form the stack of plates <NUM> of the internally-cooled diaphragm <NUM>. The process fluid plates <NUM>, the cooling fluid plates <NUM>, and/or the end plates <NUM> may be coupled with one another in any combination or sequence to form the stack of plates <NUM>. The stack of plates <NUM> formed may generally be a cylindrical or annular component configured to be at least partially disposed in the compressor stage <NUM> of the compressor <NUM>. For example, the stack of plates <NUM> may be at least partially disposed in and may further form a portion of the fluid pathway <NUM> (e.g., the return channel <NUM>) of the compressor stage <NUM>.

<FIG> illustrates a partial plan view of a first axial surface <NUM> of the end plate <NUM> illustrated in <FIG> and <FIG>, according to one or more embodiments. <FIG> illustrates a partial plan view of a second axial surface <NUM> of the end plate <NUM> of <FIG>, according to one or more embodiments. The end plate <NUM> may generally be disk-shaped. It may be appreciated, however, that the end plate <NUM> may be any shape. For example, the end plate <NUM> may be elliptical, square, or rectangular. The end plate <NUM> may define one or more cooling ports (four are shown <NUM>) extending axially therethrough. For example, as illustrated in <FIG>, the cooling ports <NUM> may extend through the end plate <NUM> from the first axial surface <NUM> to the second axial surface <NUM>. The cooling ports <NUM> may be disposed near or proximal an inner circumferential surface <NUM> or an outer circumferential surface <NUM> of the end plate <NUM>. For example, as illustrated in <FIG>, the cooling ports <NUM> may be disposed proximal the inner circumferential surface <NUM> of the end plate <NUM>.

The end plate <NUM> may define one or more cooling channels (four are shown <NUM>) along or in the first axial surface <NUM> thereof. As illustrated in <FIG>, respective first end portions <NUM> of the cooling channels <NUM> may be disposed or originate proximal the inner circumferential surface <NUM> of the end plate <NUM>. As further illustrated in <FIG>, respective second end portions <NUM> of the cooling channel <NUM> may be fluidly coupled with the cooling ports <NUM>. The cooling ports <NUM> and the cooling channels <NUM> fluidly coupled therewith may form at least a portion of the cooling pathway <NUM> (see <FIG>) extending through the internally-cooled diaphragm <NUM>. Each of the cooling channels <NUM> may generally extend from the respective first end portion <NUM>, disposed proximal the inner circumferential surface <NUM>, toward the outer circumferential surface <NUM>, and may further extend from the outer circumferential surface <NUM> to the respective second end portion <NUM>. Each of the cooling channels <NUM> may generally extend between the inner circumferential surface <NUM> and the outer circumferential surface <NUM> in a serpentine pattern or path.

<FIG> illustrates a partial plan view of a first axial surface <NUM> of the cooling fluid plate <NUM> illustrated in <FIG> and <FIG>, according to one or more embodiments. <FIG> illustrates a partial plan view of a second axial surface <NUM> of the cooling fluid plate <NUM> of <FIG>, according to one or more embodiments. The cooling fluid plate <NUM> may have a shape similar to the end plate <NUM> described above with reference to <FIG>. For example, as illustrated in <FIG>, the cooling fluid plate <NUM> may generally be disk-shaped. It should be appreciated, however, that the cooling fluid plate <NUM> may be any suitable shape (e.g., elliptical, square, or rectangular).

The cooling fluid plate <NUM>, similar to the end plate <NUM>, may define one or more cooling channels (four are shown <NUM>) along or in the first axial surface <NUM> thereof. The cooling channels <NUM> may generally extend between an inner circumferential surface <NUM> and an outer circumferential surface <NUM> of the cooling fluid plate <NUM>. For example, as illustrated in <FIG>, respective first end portions <NUM> of the cooling channels <NUM> may be disposed proximal the inner circumferential surface <NUM>, and respective second end portions <NUM> of the cooling channels <NUM> may be disposed proximal the outer circumferential surface <NUM>. As further illustrated in <FIG>, the cooling channels <NUM> may generally extend between the respective first and second end portions <NUM>, <NUM> in a serpentine pattern.

As illustrated in <FIG>, the cooling fluid plate <NUM> may define one or more cooling ports (four are shown <NUM>) extending axially therethrough from the first axial surface <NUM> to the second axial surface <NUM>. The cooling ports <NUM> may be disposed near or proximal the outer circumferential surface <NUM> of the end plate <NUM>. The cooling ports <NUM> may also be in fluid communication with the cooling channels <NUM>. For example, the cooling ports <NUM> may be in fluid communication with the respective second end portions <NUM> of the cooling channels <NUM>. The cooling ports <NUM> and/or the respective cooling channels <NUM> fluidly coupled therewith may form at least a portion of the cooling pathway <NUM> (see <FIG>) extending through the internally-cooled diaphragm <NUM>. In an exemplary embodiment, the respective first end portions <NUM> of the cooling channels <NUM> may be fluidly coupled with the respective cooling channels <NUM> (see <FIG>) of the end plate <NUM> and configured to receive the cooling fluid therefrom. For example, the first end portions <NUM> of the cooling channels <NUM> may be fluidly coupled with the cooling channels <NUM> (see <FIG>) of the end plate <NUM> via the cooling ports <NUM> and configured to receive the cooling fluid therefrom. The respective second end portions <NUM> of the cooling channels <NUM> may be fluidly coupled with a return line (not shown) and configured to direct or return the cooling fluid to a cooling fluid source (e.g., the plenum <NUM> or an external cooling fluid source) via the return line.

<FIG> illustrates a partial plan view of a first axial surface <NUM> of the process fluid plate <NUM> illustrated in <FIG> and <FIG>, according to one or more embodiments. <FIG> illustrates a cross-sectional view of the process fluid plate <NUM> taken along line 4B-4B in <FIG>, according to one or more embodiments. As illustrated in <FIG>, the return channel vanes <NUM> is coupled with the first axial surface <NUM> of the process fluid plate <NUM>. The return channel vanes <NUM> generally extend radially between an outer circumferential surface <NUM> of the process fluid plate <NUM> and an inner circumferential surface <NUM> of the process fluid plate <NUM>. The first axial surface <NUM> and/or the return channel vanes <NUM> extending therefrom may at least partially define the return passages <NUM> of the return channel <NUM> (see <FIG>). For example, adjacent return channel vanes <NUM> at least partially define respective return passages <NUM> therebetween. In another example, the first axial surface <NUM> and the return channel vanes <NUM> extending therefrom may at least partially define the respective diffusion regions <NUM> (see <FIG>) and/or the respective de-swirling regions <NUM> (see <FIG>) of the return passages <NUM>. The return channel vanes <NUM> may have any suitable shape and/or size configured to at least partially diffuse the process fluid flowing through the respective diffusion regions <NUM> of the return passages <NUM>. The return channel vanes <NUM> may also be shaped and/or sized to at least partially de-swirl the process fluid flowing through the respective de-swirling regions <NUM> of the return passages <NUM>.

An outer annular portion <NUM> of the process fluid plate <NUM> may be shaped to form the respective diffusion regions <NUM> of the return passages <NUM>. For example, as illustrated in <FIG>, the outer annular portion <NUM> may taper from the outer circumferential surface <NUM> of the process fluid plate <NUM> toward the inner circumferential surface <NUM> of the process fluid plate <NUM>. As further illustrated in <FIG>, the outer annular portion <NUM> of the process fluid plate <NUM> forms a lip or turning vane <NUM>. The turning vane <NUM> extends in an axial direction from a second axial surface <NUM> toward the first axial surface <NUM>. The turning vane <NUM> is configured to form at least a portion of the return bend <NUM> (see <FIG>). The turning vane <NUM> also is configured to at least partially separate the flow of the process fluid into each of the return passages <NUM> of the return channel <NUM>.

As illustrated in <FIG>, respective top surfaces <NUM> of the return channel vanes <NUM> may be planar or substantially planar with one another. Accordingly, the respective top surfaces <NUM> of the return channel vanes <NUM> may be mounted flush to an adjacent component (e.g., an adjacent process fluid plate <NUM>, an adjacent cooling fluid plate <NUM>, or an adjacent end plate <NUM>) of the internally-cooled diaphragm <NUM>, such that the adjacent component may at least partially provide a cover for the return passages <NUM>.

As previously discussed, the process fluid plates <NUM> (see <FIG>, <FIG>) the cooling fluid plates <NUM> (see <FIG>, <FIG>), and/or the end plates <NUM> (see <FIG>, <FIG>) are coupled with one another to form the stack of plates <NUM> of the internally-cooled diaphragm <NUM> (see <FIG>). Any number of the process fluid plates <NUM>, the cooling fluid plates <NUM>, and/or the end plates <NUM> may be used to form the stack of plates <NUM>. The number of the process fluid plates <NUM>, the cooling fluid plates <NUM>, and/or the end plates <NUM> included in the stack of plates <NUM> may be at least partially determined by one or more parameters of the compressor <NUM>. For example, the number of the process fluid plates <NUM>, the cooling fluid plates <NUM>, and/or the end plates <NUM> may be at least partially determined by a size of the compressor <NUM>, an axial length of the internally-cooled diaphragm <NUM>, a flowrate of the process gas and/or the cooling fluid, or the like, or any combination thereof.

The process fluid plates <NUM>, the cooling fluid plates <NUM>, and/or the end plates <NUM> are interleaved with one another to form at least a portion of the stack of plates <NUM>. For example, the process fluid plates <NUM> and the cooling fluid plates <NUM> may be disposed or stacked adjacent one another in an alternating sequence where one of the process fluid plates <NUM> may be followed by one of the cooling fluid plates <NUM> to form at least a portion of the stack of plates <NUM>. Similarly, the end plates <NUM> and the cooling fluid plates <NUM> may be disposed or stacked adjacent one another in an alternating sequence where one of the end plates <NUM> may be followed by one of the cooling fluid plates <NUM> to form at least a portion of the stack of plates <NUM>. In another example, the process fluid plates <NUM> and the end plates <NUM> may be disposed adjacent one another in an alternating sequence where one of the process fluid plates <NUM> may be followed by one of the end plates <NUM> to form at least a portion of the stack of plates <NUM>. In another example, the stack of plates <NUM> may be formed such that one, two, or more of the process fluid plates <NUM> may be stacked with one another and followed by one, two, or more of the cooling fluid plates <NUM> or the end plates <NUM>. In another example, the stack of plates <NUM> may be formed such that one, two, or more of the cooling fluid plates <NUM> may be stacked with one another and followed by one, two, or more of the process fluid plates <NUM> or the end plates <NUM>. In yet another example, the stack of plates <NUM> may be formed such that one, two, or more of the end plates <NUM> may be stacked with one another and followed by one, two, or more of the process fluid plates <NUM> or the cooling fluid plates <NUM>. Accordingly, it should be appreciated that the process fluid plates <NUM>, the cooling fluid plates <NUM>, and/or the end plates <NUM> may be stacked in any sequence, and the sequence of the process fluid plates <NUM>, the cooling fluid plates <NUM>, and/or the end plates <NUM> may be varied through the stack of plates <NUM>. Further, while the process fluid plates <NUM>, the cooling fluid plates <NUM>, and/or the end plates <NUM> may be illustrated as separate or discrete plates, it may be appreciated that the respective features of the process fluid plates <NUM>, the cooling fluid plates <NUM>, and/or the end plates <NUM> may be combined into a single plate. For example, the respective features of the process fluid plate <NUM> and the cooling fluid plates <NUM> discussed herein may represent opposing axial faces of a single plate.

In an exemplary embodiment, illustrated in <FIG>, opposing axial end portions of the internally-cooled diaphragm <NUM> may be formed by respective end plates <NUM>. As further illustrated in <FIG>, the cooling fluid plates <NUM> and the process fluid plates <NUM> may be disposed between the respective end plates <NUM> in an alternating sequence to form the remaining portions of the internally-cooled diaphragm <NUM>. The process fluid plates <NUM>, the cooling fluid plates <NUM>, and/or the end plates <NUM> may be stacked with one another in any orientation. For example, the process fluid plates <NUM>, the cooling fluid plates <NUM>, and/or the end plates <NUM> may be oriented such that the respective first axial surfaces <NUM>, <NUM>, <NUM> thereof face an upstream side of the compressor <NUM>. In another example, the process fluid plates <NUM>, the cooling fluid plates <NUM>, and/or the end plates <NUM> may be oriented such that the respective first axial surfaces <NUM>, <NUM>, <NUM> thereof face a downstream side of the compressor <NUM>. In an exemplary embodiment, illustrated in <FIG>, the end plates <NUM> may be oriented such that the respective first axial surfaces <NUM> thereof face opposing sides (i.e., upstream and downstream sides) of the compressor <NUM>. As further illustrated in <FIG>, the respective first axial surfaces <NUM>, <NUM> of the cooling fluid plates <NUM> and the process fluid plates <NUM> may face the upstream side of the compressor <NUM>.

In an exemplary operation, with continued reference to <FIG>, the rotary shaft <NUM> may rotate the impeller <NUM> at a speed sufficient to draw a process fluid into the casing <NUM> of the compressor <NUM>. The rotation of the impeller <NUM> may also draw the process fluid to and through the impeller <NUM> and urge the process fluid to a tip <NUM> of the impeller <NUM>, thereby increasing the velocity of the process fluid. The plurality of blades <NUM> of the impeller <NUM> may raise the velocity and energy of the process fluid and direct the process fluid from the impeller <NUM> to the diffuser <NUM> fluidly coupled therewith. The diffuser <NUM> may receive the process fluid from the impeller <NUM> and convert the kinetic energy (e.g., flow or velocity) of the process fluid to potential energy (e.g., increased static pressure) by decreasing the velocity of the process fluid flowing therethrough. The plurality of diffuser vanes <NUM> may direct or deflect the flow of the process fluid through the diffuser <NUM> to decrease the velocity of the process fluid and increase the static pressure. The conversion of the velocity of the process fluid to increased static pressure may thereby compress the process fluid, and the compression of the process fluid may generate heat (e.g., heat of compression) to increase a temperature of the compressed process fluid. The return bend <NUM> may receive the compressed process fluid from the diffuser <NUM> and direct or turn the flow of the process fluid radially inward toward the internally-cooled diaphragm <NUM> defining the return channel <NUM>.

The internally-cooled diaphragm <NUM> least partially separates or divides the flow of the process fluid from the return bend <NUM> into the return passages <NUM> of the return channel <NUM>. For example, the respective turning vanes <NUM> formed about the respective outer annular portions <NUM> (see <FIG>) of the process fluid plates <NUM> at least partially separate the flow of the process fluid from the return bend <NUM> into separate flows, and each separate flow of the process fluid may be directed to a respective return passage <NUM> of the return channel <NUM>. The internally-cooled diaphragm <NUM> least partially diffuses the process fluid flowing through each of the return passages <NUM> of the return channel <NUM>. For example, the process fluid may be at least partially diffused through respective diffusion regions <NUM> of the return passages <NUM>. The diffusion of the process fluid through the respective diffusion regions <NUM> of the return passages <NUM> may further reduce the velocity and increase the pressure or compression of the process fluid. The diffusion of the process fluid through the respective diffusion regions <NUM> of the return passages <NUM> may also increase the stability and decrease separation of the process fluid. For example, boundary layers of the process fluid may be less susceptible to separation when utilizing the diffusion regions <NUM>.

The internally-cooled diaphragm <NUM> also at least partially de-swirls the flow of the process fluid flowing through the return passages <NUM> of the return channel <NUM>. For example, the respective de-swirling regions <NUM> of the return passages <NUM> and/or the respective return channel vanes <NUM> disposed in the return passages <NUM> may at least partially de-swirl the process fluid flowing through the return channel <NUM>. The diffused, de-swirled process fluid flowing through each of the return passages <NUM> may collect or be combined with one another in a collection region <NUM> (see <FIG>) of the return channel <NUM>. The process fluid in the collection region <NUM> of the return channel <NUM> may be discharged from the compressor <NUM> or introduced to a downstream compressor stage (not shown).

As previously discussed, the compression of the process fluid through the fluid pathway <NUM> may generate heat to thereby increase the temperature of the process fluid. Accordingly, a cooling fluid is directed to and through the cooling pathway <NUM> of the internally-cooled diaphragm <NUM> to at least partially absorb the heat from the process fluid flowing through the fluid pathway <NUM>. In one example, the cooling fluid directed to the cooling pathway <NUM> of the internally-cooled diaphragm <NUM> may be contained in an external cooling fluid source (not shown) and delivered to the cooling pathway <NUM> via a supply line (not shown). In another example, illustrated in <FIG>, the cooling fluid directed to the cooling pathway <NUM> of the internally-cooled diaphragm <NUM> may be contained in the plenum <NUM> and delivered to the cooling pathway <NUM> via the conduits <NUM> extending through the diffuser vanes <NUM>. The cooling fluid delivered to the cooling pathway <NUM> via the conduits <NUM> may be directed to the end plate <NUM> of the internally-cooled diaphragm <NUM>. For example, the cooling fluid may be delivered from the conduits <NUM> to the respective first end portions <NUM> (see <FIG>) of the cooling channels <NUM> of the end plate <NUM>. The cooling fluid may flow from the respective first end portions <NUM> to the respective second end portions <NUM> (see <FIG>) of the cooling channels <NUM> via the serpentine path.

The cooling fluid may flow from the end plate <NUM> to one or more of the cooling fluid plates <NUM> (see <FIG>) of the internally-cooled diaphragm <NUM>. For example, the cooling fluid from the end plate <NUM> may be directed to the respective cooling channels <NUM> (see <FIG>) of the cooling fluid plates <NUM> via the respective cooling ports <NUM>. The cooling fluid may flow radially outward through the respective cooling channels <NUM> of each of the cooling fluid plates <NUM> to thereby absorb at least a portion of the heat contained in the process fluid flowing through the return passages <NUM> of the internally-cooled diaphragm <NUM>. For example, as previously discussed, the cooling fluid plates <NUM> may be stacked adjacent the process fluid plates <NUM> (see <FIG>, <FIG>). By stacking the cooling fluid plates <NUM> adjacent the process fluid plates <NUM>, heat from the process fluid flowing through the respective return passages <NUM> may be transferred to the process fluid plates <NUM>, and subsequently transferred to the cooling fluid plates <NUM> thermally coupled therewith. The heat may be transferred from the cooling fluid plates <NUM> to the cooling fluid flowing through the respective cooling channels <NUM> thereof. Further, in some embodiments where the cooling fluid plates <NUM> may be mounted flush to the respective second axial surfaces <NUM> of the process fluid plates <NUM>, at least a portion of the heat from the process fluid plates <NUM> may be transferred directly to the cooling fluid, as the second axial surface <NUM> of the process fluid plates <NUM> may provide the cover for the respective cooling channels <NUM> of the cooling fluid plates <NUM>. Similarly, in embodiments where the process fluid plates <NUM> may be mounted flush to the second axial surfaces <NUM> of the cooling fluid plates <NUM>, at least a portion of the heat from the process fluid flowing through the respective return passages <NUM> of the process fluid plates <NUM> may be transferred directly to the cooling fluid plates <NUM>, as the respective second axial surfaces <NUM> of the cooling fluid plates <NUM> may provide the cover for the respective return passages <NUM> of the process fluid plates <NUM>.

The cooling fluid flowing through the respective cooling channels <NUM> of the cooling fluid plates <NUM> may then be discharged from the cooling fluid plates <NUM> via the respective cooling fluid ports <NUM> thereof. The cooling fluid discharged from the cooling fluid plates <NUM> may then be discharged from the internally-cooled diaphragm <NUM>. For example, the cooling fluid discharged from the respective cooling fluid ports <NUM> of the cooling fluid plates <NUM> may be discharged from the internally-cooled diaphragm <NUM> and directed to a cooling fluid drain (not shown) or an external cooling fluid drain (not shown) via a return line (not shown). In another example, the cooling fluid discharged from the respective cooling fluid ports <NUM> of the cooling fluid plates <NUM> may be discharged from the internally-cooled diaphragm <NUM> via the end plate <NUM>. For example, the cooling fluid discharged from the cooling fluid plates <NUM> may be directed to and through the respective cooling channels <NUM> of the end plate <NUM>, and discharged from the end plate <NUM> to the cooling fluid drain (not shown) or the external cooling fluid drain (not shown) via the return line (not shown).

Claim 1:
An internally-cooled diaphragm (<NUM>) for a compressor (<NUM>), comprising:
an annular body configured to cool a process fluid flowing through a fluid pathway (<NUM>) of the compressor (<NUM>), the annular body defining:
a return channel (<NUM>) of the fluid pathway (<NUM>), the return channel (<NUM>) comprises a plurality of return passages (<NUM>) which are configured to at least partially diffuse and de-swirl the process fluid flowing therethrough; and
a cooling pathway (<NUM>) in thermal communication with the fluid pathway (<NUM>), the cooling pathway (<NUM>) configured to receive a coolant to absorb heat from the process fluid flowing through the return channel (<NUM>),
characterised in that
the annular body comprises a plurality of process fluid plates (<NUM>) including a plurality of return channel vanes (<NUM>) extending from a first axial surface (<NUM>) thereof, the plurality of return channel vanes (<NUM>) at least partially defining the plurality of return passages (<NUM>) of the return channel (<NUM>),
and in that
the annular body further comprises a plurality of cooling fluid plates (<NUM>), wherein the plurality of process fluid plates (<NUM>) and the plurality of cooling fluid plates (<NUM>) are coupled with one another such that the plurality of process fluid plates (<NUM>) and the plurality of cooling fluid plates (<NUM>) at least partially define a plurality of return passages (<NUM>),
and in that
each process fluid plate (<NUM>) of the plurality of process fluid plates (<NUM>) comprises a plurality of turning vanes (<NUM>) extending axially from an outer annular portion thereof, each turning vanes (<NUM>) of the plurality of turning vanes (<NUM>) is configured to separate the process fluid into a plurality of separated flows and direct each separated flow of the plurality of separated flows to a respective return passage (<NUM>) of the plurality of return passages (<NUM>).