BACKGROUND 
       [0001]    The subject matter disclosed herein relates to compressor devices (e.g., centrifugal compressors) and, in particular, to diffusers and diffuser vanes for a compressor device. 
         [0002]    Compressor devices (e.g., centrifugal compressors) use a diffuser assembly to convert kinetic energy of a working fluid into static pressure by slowing the velocity of the working fluid through an expanding volume region. An example of a diffuser assembly typically utilizes several diffuser vanes in circumferential arrangement about an impeller. The design (e.g., shapes and sizes) of the diffuser vanes, in combination with the preferred orientation of the leading edge and the trailing edge of the diffuser vanes with respect to the flow of the working fluid, often determine how the diffuser vanes are affixed in the diffuser assembly. 
         [0003]    To add further improvement and flexibility to the design, some examples of a diffuser assembly incorporate variable diffuser vanes. These types of diffuser vanes move to change the orientation of the leading edge and the trailing edge. This feature helps to tune operation of the compressor device. Known designs for variable diffuser vanes rotate about an axis that resides in the lower half, i.e., closer to the leading edge than the trailing edge of the diffuser vanes. 
         [0004]    Some configurations of compressor devices do not comport with use of variable diffuser vanes. Multi-stage compressors, for example, often forego use of variable diffuser vanes because of problems with maintaining desired flow and pressure rates for the working fluid; namely, that use of variable diffuser vanes can reduce the operating range of the multi-stage compressor device. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0005]    This disclosure describes embodiments of systems and methods that permit use of variable diffuser vanes in multi-stage compressor devices. These embodiments deploy a flow sensor in combination with a variable diffuser vane to align the variable diffuser vane with the direction of flow of the working fluid. This configuration pre-empts the operational difficulties of previous designs by providing independent control over the diffuser vanes in the individual stages of the multi-stage compressor device. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    Reference is now made briefly to the accompanying drawings, in which: 
           [0007]      FIG. 1  depicts a schematic view of an exemplary embodiment of a multi-stage compressor device; 
           [0008]      FIG. 2  depicts a schematic view of an exemplary embodiment of a system for controller operation of a compressor device; e.g., the multi-stage compressor device of  FIG. 1 ; 
           [0009]      FIG. 3  depicts a flow diagram of an exemplary embodiment of a method for operating a compressor device, e.g., the multi-stage compressor device of  FIG. 1 ; 
           [0010]      FIG. 4  depicts a perspective view of an example of a diffuser assembly for use in a compressor device, e.g., the multi-stage compressor device of  FIG. 1 ; 
           [0011]      FIG. 5  depicts a top view of the diffuser assembly of  FIG. 4  with a flow sensor in a first sensor position and a second sensor position; 
           [0012]      FIG. 6  depicts a top view of the diffuser assembly of  FIG. 4  with the diffuser vane in a first vane position and a second vane position; 
           [0013]      FIG. 7  depicts a detail view of the leading edge of the exemplary diffuser vane of  FIG. 4 ; 
           [0014]      FIG. 8  depicts a flow diagram of an exemplary embodiment of a method for operating a compressor device, e.g., the multi-stage compressor device of  FIG. 1 ; and 
           [0015]      FIG. 9  depicts a high-level wiring schematic of an example of a controller for use in a system, e.g., the system of  FIG. 2 . 
       
    
    
       [0016]    Where applicable like reference characters designate identical or corresponding components and units throughout the several views, which are not to scale unless otherwise indicated. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0017]      FIG. 1  illustrates a schematic view of an exemplary embodiment of a compressor device  100 . The compressor device  100  includes an inlet  102 , an outlet  104 , and one or more stages (e.g., a first stage  106  and a second stage  108 ) disposed in flow connection with the inlet  102  and the outlet  104 . The stages  106 ,  108  include an impeller (e.g., a first impeller  110  and a second impeller  112 ) and a diffuser assembly (e.g., a first diffuser assembly  114  and a second diffuser assembly  116 ). The diffuser assemblies  114 ,  116  include one or more diffuser vanes (e.g., a first diffuser vane  118  and a second diffuser vane  120 ) and a flow sensor (e.g., a first flow sensor  122  and a second flow sensor  124 ). The compressor device  100  also includes a drive unit  126  and a drive shaft  128 , which couples with the drive unit  126  and with one or more of the impellers  110 ,  112 . 
         [0018]    Embodiments of the compressor device  100  find use in a variety of settings and industries including automotive industries, electronics industries, aerospace industries, oil and gas industries, power generation industries, petrochemical industries, and the like. During one implementation, the shaft  128  transfers power from the drive unit  126  to rotate the first impeller  110  and the second impeller  112 . Rotation of the first impeller  110  draws a working fluid (e.g., air) through the inlet  102 . In the first stage  106 , the first impeller  110  compresses the working fluid. The compressed working fluid flows into the first diffuser assembly  114 , which allows the working fluid to expand before the working fluid enters the second stage  108 . In the second stage  108 , the working fluid undergoes compression and expansion by, respectively, the second impeller  112  and the second diffuser assembly  116 . In one embodiment, the compressor device  100  can couple at the outlet  104  with industrial piping to expel the working fluid under pressure and/or with certain designated flow parameters as desired. 
         [0019]    Examples of the diffuser vanes  118 ,  120  can move (e.g., rotate) from one position (e.g., a first position) to another position (e.g., a second position), and vice versa. Movement between the first position and the second position allows the diffuser vanes  118 ,  120  to align with the direction of flow of the working fluid. This feature avoids flow separation of the working fluid from the surfaces of the diffuser vane  118 ,  120 . 
         [0020]    The flow sensors  122 ,  124  monitor the direction of flow of the working fluid upstream of the diffuser vanes  118 ,  120 . As the direction of the flow changes, e.g., due to changes in operation of the compressor device  100 , the flow sensor  122  will generate a signal. Examples of the signal convey information to indicate the extent, direction, and other characteristics relevant to the direction of the flow. The controller  132  can process this signal and, in response, generate an output to impart changes to the position of the diffuser vanes  118 ,  120 . In one example, the output encodes instructions to move the actuators  134 ,  136  which in turn causes the diffuser vanes  118 ,  120  to change position, e.g., from the first position to the second position. 
         [0021]    As shown in  FIG. 2 , the compressor device  100  can form part of a system  130  (also “control system  130 ”), which can change operating settings for the first diffuser assembly  114  and the second diffuser assembly  116  independent of one another during operation of the compressor device  100 . The system  130  includes a controller  132 , which couples with the flow sensors  122 ,  124  and with actuators (e.g., a first actuator  134  and a second actuator  136 ). Examples of the actuators  134 ,  136  change the position of, respectively, the first diffuser vane  118  and the second diffuser vane  120 . In one embodiment, the controller  132  (and/or one or more other devices in the system  130 ) can communicate via a network  138  with a peripheral device  140  (e.g., a display, a computer, a smartphone, a laptop, a tablet, etc.) and/or an external server  142 . 
         [0022]    The controller  132  can comprise computers and computing devices with processors and memory that can store and execute certain executable instructions, software programs, and the like. The controller  132  can be a separate unit, e.g., part of a control unit that operates the compressor device  100  and other equipment. In other examples, the controller  132  integrates with the compressor device  100 , e.g., as part of the hardware and/or software configured on such hardware. In still other examples, the controller  132  can be located remote from the compressor device  100 , e.g., in a separate location where the controller  132  can issue commands and instructions using wireless and wired communication, e.g., via the network  124 . 
         [0023]    Examples of the system  130  orient one or both of the diffuser vanes  118 ,  120  to modify flow and expansion that occurs as the working fluid transits the corresponding diffuser assemblies  114 ,  116 . By utilizing separate flow sensors  122 ,  124  to measure the direction of flow upstream of the respective diffuser vanes  118 ,  120 , the system  130  can account for variations in flow that occur from stage to stage, e.g., from stage  106  to stage  108 . The system  130  can use the information about the direction of flow to instruct the actuators  134 ,  136  to place the diffuser vanes  118 ,  120  in different positions relative to one another. This feature effectively decouples operation of the compressor device  100  in the first stage  106  from the second stage  108 , which allows the diffuser vanes  118 ,  120  to operate independent of one another and, in one example, independent of additional stages without having an adverse effect on overall performance of the compressor device  100 . 
         [0024]      FIG. 3  depicts a flow diagram of an exemplary method  200  to improve performance of a compressor device (e.g., compressor device  100  of  FIG. 1 ). The method  200  includes, at step  202 , receiving a first signal from a first flow sensor and, at step  204 , receiving a second signal from a second flow sensor. In one embodiment, the first signal and the second signal encode information that identifies a first direction and a second direction of flow for a working fluid upstream of, respectively, a first diffuser vane and a second diffuser vane. The method  200  also includes, at step  206 , identifying a first position for the first diffuser vane and the second diffuser vane. In one example, the first position aligns the first diffuser vane and the second diffuser vane with the first direction of flow of the working fluid. The method  200  further includes, at step  208 , generating an output encoding instructions to move the first diffuser vane and the second diffuser vane to the first position. 
         [0025]    In one embodiment, the first signal (e.g., at step  202 ) and the second signal (e.g., at step  204 ) indicate the position of the first flow sensor and the second flow sensor. To illustrate,  FIG. 4  depicts a perspective view of an example of a diffuser assembly  300  for use in a compressor device (e.g., compressor device  100  ( FIG. 1 )). The diffuser assembly  300  includes a diffuser vane  302  and a flow sensor  304  upstream of the diffuser vane  302 . In one example, the flow sensor  304  has a base element  306  and a directional element  308  disposed in the path of a flow F of a working fluid. The diffuser vane forms a vane body  310  with a leading edge  312  and a trailing edge  314 . A chord length L defines the straight-line distance between the leading edge  312  and the trailing edge  314 . The vane body  310  forms an aerodynamic shape (e.g., an airfoil) with a suction side surface  316  and a pressure side surface  318  identified relative to the orientation and angle of attack of the leading edge  312  relative to the flow F. At the leading edge  312 , the vane body  310  converges to a tip  320 . 
         [0026]    The flow sensor  304  can move and, in one example, the directional element  308  rotates relative to the base element  306  to indicate the direction of flow F. Examples of the base element  306  can secure to components of the diffuser assembly  300 . These components can include wall members, frame member, and other structure (e.g., volute) that can position the flow sensor  304  in the flow of the working fluid. For example, the flow base element  306  can reside a bore and/or counter bore in such structure to position the directional element  308  in the flow path. Examples of the base element  306  can include a pin and/or other bearing element, which receives the directional element  308 . The pin acts as a pivot about which the directional element  308  can freely rotate. When placed in the path of flow F, the directional element  308  will align with the direction of the flow F. In one example, the base element  306  can comprise a rotary potentiometer and/or other like devices that can measure angular displacement. The rotary potentiometer can couple with the directional element  308  to register changes in the position of the directional element  308  in response to the direction of flow F. 
         [0027]    With reference to  FIG. 5 , during one implementation, a compressor device may operate in a manner that causes the flow F to flow in a number of different directions (e.g., a first flow direction F 1  and a second flow direction F 2 ). The directional element  308  assumes one of a first sensor position  322  and a second sensor position  324 , which correspond to, respectively, the first flow direction F 1  and the second flow direction F 2 . In one example, the flow sensor  304  can register the change in the position of the directional element  308 , e.g., between the first sensor position  322  and the second sensor position  324 . 
         [0028]    Examples of the first signal and/or the second signal can encode information to identify the position and/or the relative change in position of the directional element  308 . In one example, the first signal and the second signal may encode an angular position to each of the first sensor position  322  and the second sensor position  324 . Examples of the angular position can utilize a radial scale that covers 360°, wherein the first position  322  and the second position  324  assume different values on the radial scale, e.g., 0° for the first position  322  and 300° for the second position  324 . In other examples, the first signal and the second signal my encode an angular offset to each of the first sensor position  322  and the second sensor position  324 . The angular offset can define a value, e.g., a radial value, on the radial scale by which the first sensor position  322  and the second sensor position  324  deviate relative to a fixed or home position. For purposes of the present example of  FIG. 5 , the radial value for the first sensor position  322  is 0 and or 0° and the radial value for the second sensor position  324  is −30 and/or −30°. 
         [0029]    The steps for identifying a first position (e.g., at step  206 ) for the diffuser vane  302  can use the information in the first signal and the second signal to align the diffuser vane  302  with the direction of flow F. In this connection,  FIG. 6  illustrates an example of the diffuser vane  302  in a first vane position  326  and a second vane position, identified by phantom lines and the numeral  328 . In one example, the vane body  302  can rotate about a rotation axis  330 , which permits the position of the trailing edge  314  to change relative to, in one example, the leading edge  314 . This disclosure also contemplates configurations of the diffuser vane  302  in which the rotation axis  330  is located at various positions, e.g., in positions spaced apart from the leading edge  312  and the trailing edge  314  along the chord length L ( FIGS. 4 and 5 ). In these other configurations, both the leading edge  312  and the trailing edge  314  can rotate, e.g., about the rotation axis  330 . 
         [0030]    Implementations in which the trailing edge  314  rotates the leading edge  312  are advantageous to accommodate the first flow direction F 1  and the second flow direction F 2 . As shown in the example of  FIG. 6 , despite the relatively large angular displacement of the trailing edge  314  that occurs, the leading edge  312  is secured on the rotation axis  330  to limit changes to the position of the leading edge  312 , e.g., as the trailing edge  314  moves between the first vane position  326  and the second vane position  328 . This feature maintains the orientation of the leading edge  312  with the second flow direction F 2  to reduce the likelihood of flow separation, while providing adequate adjustment of the trailing edge  314  to dictate changes in the performance (e.g., of compressor device  100  of  FIGS. 1 and 2 ). 
         [0031]      FIG. 7  illustrates a detail view of the diffuser vane  302 . The example of  FIG. 7  shows that the tip  320  is round and/or has a curvilinear outer surface  332  defined by a radius R TIP  that extends from a center axis  334 . Other examples the tip  320  exhibit a shape (e.g., a point) that maintains the aerodynamics of the vane body  310 . This disclosure also contemplates configurations of the tip  320  having less than optimal aerodynamic shapes (e.g., blunt shapes) as desired. 
         [0032]    In the example of  FIG. 7  (and  FIG. 6 ), the rotation axis  330  resides proximate the leading edge  312  and, for example, within 5% or less of the chord length L ( FIG. 4 ) (as measured from the leading edge  312 ). Depending on the size and shape of the tip  320 , the rotation axis  330  can also be found within an area that the radius R TIP  defines about the center axis  330 . In one example, the rotation axis  330  is coaxial with the center axis  334  of the tip  320 . 
         [0033]    Examples of the diffuser vane  302  can comprise various materials and combinations, compositions, and derivations thereof. These materials include metals (e.g., steel, stainless steel, aluminum), metal alloys, high-strength plastics, composites, and the like. Material selection may depend on the type and composition of the working fluid. For example, working fluids with caustic properties may require that the diffuser vanes comprise relatively inert materials and/or materials that are chemically inactive with respect to the working fluid, and/or have one or more coatings and/or surface treatments that provide prevent corrosion, erosion, or other degradation of the surface of the diffuser vanes. 
         [0034]    Geometry for the diffuser vane  302  is determined as part of the design, build, and fitting of the compressor device for the application. The geometry can include airfoil shapes, e.g., the shape shown in  FIG. 4  for the vane body  310 , examples of which take the form of wings and blades and/or other forms that can generate lift. In one embodiment, the diffuser vane  302  can mount, e.g., to one of the wall members, using fasteners and fastening techniques that permit rotation of the diffuser vanes about the leading edge. Screws, bolts, pins, bearings, and like components can be used to maintain the position of the leading edge, while further allowing the trailing edge to change position as contemplated herein. These fasteners can secure to the wall members of the diffuser assembly, which can comprise pieces separate from the components of the compressor device or can integrate with existing hardware found in the compressor device. 
         [0035]    Referring back to the method  200  of  FIG. 3 , the steps for generating an output (e.g., at step  206 ) can cause the diffuser vane  302  to move, e.g., as between the first position  326  and the second position  328 . The output can comprise any signal (e.g., analog and/or digital) that can encode instructs to operate a device. In the examples herein, the output can cause an actuator to move, which can facilitate movement either directly and/or indirectly of the diffuser vane  302  among and between one or more of the first position  326  and the second position  328 . 
         [0036]      FIG. 8  illustrates another exemplary embodiment of a method  400  to operate a compressor device. The method  400  includes, at step  402 , receiving a first signal from the first flow sensor encoding information that identifies a first direction of flow for a working fluid upstream of the first diffuser vane. The method also includes, at step  404 , receiving a second signal from the second flow sensor encoding information that identifies a second direction of flow for the working fluid upstream of the second diffuser vane. The method further includes, at step  406 , comparing the first direction and the second direction to, respectively, a first reference direction and a second reference direction. In one example, the first reference direction and the second reference direction relate to a value for the first direction and the second direction. As shown in  FIG. 8 , the method  400  also includes, at step  408 , identifying a first position for the first diffuser vane and the second diffuser vane aligning the first diffuser vane and the second diffuser vane with, respectively, the first direction and the second direction of the working fluid. In one embodiment, this step can include, at step  410 , determining whether the first position and the second position are different from the first reference position and the second reference position. If the first position and/or the second position are different, then the method  400  can include, at step  412 , selecting a first increment by which to move the first diffuser vane and/or a second increment by which to move the second diffuser vane. In one example, the first increment defines the relative position of the first direction with respect to the first reference direction and the second increment defining the relative position of the second direction with respect to the second reference direction. The method  400  can also include, at step  414 , generating an output encoding instructions to move the first diffuser vane and the second diffuser vane to the first position. In one example, the instructions cause the first diffuser vane and the second diffuser vane to move from the first position to a second position, wherein the second position is defined relative to the first position for the first diffuser vane by the first increment and for the second diffuser vane by the second increment. 
         [0037]    In view of the foregoing discussion, one or more of the steps of the methods  200  and  400  can be coded as one or more executable instructions (e.g., hardware, firmware, software, software programs, etc.). These executable instructions can be part of a computer-implemented method and/or program, which can be executed by a processor and/or processing device. Examples of the controller  132  ( FIG. 2 ) can execute these executable instruction to generate certain outputs, e.g., a signal that encodes instructions to change the position of the diffuser vanes as suggested herein. 
         [0038]      FIG. 9  depicts a schematic diagram that presents, at a high level, a wiring schematic for a controller  500  that can processing data (e.g., signals) to generate an output that instructs operation of a compressor device (e.g., compressor device  100  of  FIGS. 1 and 2 ). The controller  500  can be incorporated as part of compressor device to provide an integrated, effectively stand alone system. In other alternatives, the controller  500  can remain separate and/or as part of a control system, which can also monitor various operations of the compressor device as well as the systems coupled thereto. 
         [0039]    In one embodiment, the controller  500  includes a processor  502 , memory  504 , and control circuitry  506 . Busses  508  couple the components of the controller  500  together to permit the exchange of signals, data, and information from one component of the controller  500  to another. In one example, the control circuitry  506  includes sensor driver circuitry  510  which couples with one or more sensors (e.g., first flow sensor  512  and second flow sensor  514 ) and motor drive circuitry  516  that couples with a drive unit  518 . The control circuitry  506  also includes an actuator drive circuitry  520 , which couples with one or more actuators (e.g., first actuator  522  and second actuator  524 ), and a radio circuitry  526  that couples to a radio  528 , e.g., a device that operates in accordance with one or more of the wireless and/or wired protocols for sending and/or receiving electronic messages to and from a peripheral device  530  (e.g., a smartphone). As also shown in  FIG. 9 , memory  504  can include one or more software programs  532  in the form of software and/or firmware, each of which can comprise one or more executable instructions configured to be executed by the processor  502 . 
         [0040]    This configuration of components can dictate operation of the controller  500  to analyze data, e.g., information encoded by the signals from sensors  512 ,  514  and/or drive unit  518 , to identify appropriate changes to the diffuser vanes and/or other changes to other operating properties (e.g., motor speed) of the compressor device. For example, the controller  500  can provide signals (or inputs or outputs) to align diffuser vanes in various stages of the compressor device with the direction of flow, independent of the other stages and without disrupting operation (e.g., output pressure) of the compressor device. 
         [0041]    The controller  500  and its constructive components can communicate amongst themselves and/or with other circuits (and/or devices), which execute high-level logic functions, algorithms, as well as executable instructions (e.g., firmware instructions, software instructions, software programs, etc.). Exemplary circuits of this type include discrete elements such as resistors, transistors, diodes, switches, and capacitors. Examples of the processor  502  include microprocessors and other logic devices such as field programmable gate arrays (“FPGAs”) and application specific integrated circuits (“ASICs”). Although all of the discrete elements, circuits, and devices function individually in a manner that is generally understood by those artisans that have ordinary skill in the electrical arts, it is their combination and integration into functional electrical groups and circuits that generally provide for the concepts that are disclosed and described herein. 
         [0042]    The structure of the components in the controller  500  can permit certain determinations as to selected configuration and desired operating characteristics that an end user convey via the graphical user interface or that are retrieved or need to be retrieved by the device. For example, the electrical circuits of the controller  500  can physically manifest theoretical analysis and logical operations and/or can replicate in physical form an algorithm, a comparative analysis, and/or a decisional logic tree, each of which operates to assign the output and/or a value to the output that correctly reflects one or more of the nature, content, and origin of the changes that occur and that are reflected by the inputs to the controller  500  as provided by the corresponding control circuitry, e.g., in the control circuitry  506 . 
         [0043]    In one embodiment, the processor  502  is a central processing unit (CPU) such as an ASIC and/or an FPGA that is configured to instruct and/or control operation one or more devices. This processor can also include state machine circuitry or other suitable components capable of controlling operation of the components as described herein. The memory  504  includes volatile and non-volatile memory and can store executable instructions in the form of and/or including software (or firmware) instructions and configuration settings. Each of the control circuitry  506  can embody stand-alone devices such as solid-state devices. Examples of these devices can mount to substrates such as printed-circuit boards and semiconductors, which can accommodate various components including the processor  502 , the memory  504 , and other related circuitry to facilitate operation of the controller  500 . 
         [0044]    However, although  FIG. 9  shows the processor  502 , the memory  504 , and the components of the control circuitry  506  as discrete circuitry and combinations of discrete components, this need not be the case. For example, one or more of these components can comprise a single integrated circuit (IC) or other component. As another example, the processor  502  can include internal program memory such as RAM and/or ROM. Similarly, any one or more of functions of these components can be distributed across additional components (e.g., multiple processors or other components). 
         [0045]    Moreover, as will be appreciated by one skilled in the art, aspects of the present invention may be embodied as a system, method or computer program product. Accordingly, aspects of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, aspects of the present invention may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied thereon. 
         [0046]    Any combination of one or more computer readable medium(s) may be utilized. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. Examples of a computer readable storage medium include an electronic, magnetic, electromagnetic, and/or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. 
         [0047]    A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms and any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. 
         [0048]    Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing. 
         [0049]    Computer program code for carrying out operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language and conventional procedural programming languages. The program code may execute entirely on the user&#39;s computer, partly on the user&#39;s computer, as a stand-alone software package, partly on the user&#39;s computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user&#39;s computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). 
         [0050]    Aspects of the present invention are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. 
         [0051]    These computer program instructions may also be stored in a computer readable medium that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer readable medium produce an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks. 
         [0052]    The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. 
         [0053]    Accordingly, a technical effect of embodiments of the systems and methods disclosed herein is to change the position of one or more diffuser vanes to align with the direction of flow of the working fluid. 
         [0054]    As used herein, an element or function recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural said elements or functions, unless such exclusion is explicitly recited. Furthermore, references to “one embodiment” of the claimed invention should not be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. 
         [0055]    This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.
Embodiments of systems and methods permit use of variable diffuser vanes in multi-stage compressor devices. These embodiments deploy a flow sensor to identify the direction of flow for a working fluid that transits the stages of the compressor device. In one embodiment, the flow sensor generates a signal, which a controller processes to align a variable diffuser vane with the direction of flow of the working fluid. This configuration pre-empts the operational difficulties of previous designs by providing independent control over the diffuser vanes in the individual stages of the multi-stage compressor device.