Abstract:
A filter system and method utilizing a plurality of filters each with an electrically conductive material portion for conducting an electric current while the filter maintains a tight seal and for not conducting the electric current when the filter does not maintain the tight seal.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The subject matter disclosed herein relates to a system for detecting the loss of sealing integrity in an air filtration system, in particular, in a filter house having numerous filter elements. 
         [0002]    Air filtration systems for large gas turbines employ filter houses having numerous filter elements positioned on tube sheets. The filters are held securely in place by various mechanical means under sufficient pressure to provide an air tight seal such that there are no gaps through which dirty air can bypass the filter elements. Mounting devices and methods for securing the filter elements tend to vary with filter house design, location, filter type, and manufacturer. Widely used retaining instruments include clamps, and locking nut and bolt arrangements. Such mechanical devices are subject to vibrations caused by motors and air flow which loosens mechanically secured devices eventually resulting in loss of air tight seals between the filter elements and the tube sheets. Improper sealing of the filters provides an avenue, e.g., a gap, for dirty air to bypass the filter. Improper sealing can also be caused by improper initial installation, poor quality of installation materials, and distortion in the filter element sealing surface, all of which may not be discovered by visual inspection. The bypass of filter elements by dirty, particulate laden air can accelerate loading of another filter in a downstream location and can accelerate wear and erosion of mechanical components in, for example, a gas turbine compressor. 
         [0003]    Current filter house designs can comprise hundreds of filter elements. Auxiliary systems monitor relative humidity, ambient temperature, and other parameters that are critical to, for example, gas turbine performance. A common premise is that all the air entering the compressor is pure air that has passed through the air filtration system. Opacity detectors, e.g., photodetectors, are often used to monitor incoming air to infer that there is a leak in the filter grid of such systems via detected changes in opacity caused by airborne contaminants such as dust or other particles. However, such detection systems do not pinpoint where a sealing flaw is located. 
         [0004]    The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0005]    A filter system and method utilizing a plurality of filters each with an electrically conductive material portion for conducting an electric current while the filter maintains a tight seal and for not conducting the electric current when the filter does not maintain the tight seal. Advantages that may be realized in the practice of some disclosed embodiments of the filter leak detection system includes increased mechanical performance of systems that rely on a properly filtered air supply, automatic identification of the location of a leak, decreased mechanical erosion, fewer shutdowns due to component failures, and reduction in maintenance costs. 
         [0006]    One embodiment comprises a filter system having a tube sheet with a plurality of filter elements disposed on it. The filter elements each have an electrically conductive material portion in electrical contact with a voltage source when the filter elements maintain a tight seal on the tube sheet. The electrically conductive material portions are not in electrical contact with the voltage source if the filter elements do not maintain the tight seal. 
         [0007]    Another embodiment comprises a filter house having at a voltage source and a plurality of mounting locations for receiving filter elements that have electrically conductive material portions. The mounting locations each have an electrical contact for connecting the electrically conductive material portion of the filter elements to the voltage source. 
         [0008]    Another embodiment comprises disposing an electrically conductive circuit on a tube sheet for contacting electrically conductive filter elements installed on the tube sheet, and installing the filter elements on the tube sheet. Electrical characteristics of the filter elements are monitored after the installation. 
         [0009]    This brief description of the invention is intended only to provide a brief overview of subject matter disclosed herein according to one or more illustrative embodiments, and does not serve as a guide to interpreting the claims or to define or limit the scope of the invention, which is defined only by the appended claims. This brief description is provided to introduce an illustrative selection of concepts in a simplified form that are further described below in the detailed description. This brief description is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    So that the manner in which the features of the invention can be understood, a detailed description of the invention may be had by reference to certain embodiments, some of which are illustrated in the accompanying drawings. It is to be noted, however, that the drawings illustrate only certain embodiments of this invention and are therefore not to be considered limiting of its scope, for the scope of the invention encompasses other equally effective embodiments. The drawings are not necessarily to scale, emphasis generally being placed upon illustrating the features of certain embodiments of the invention. In the drawings, like numerals are used to indicate like parts throughout the various views. Thus, for further understanding of the invention, reference can be made to the following detailed description, read in connection with the drawings in which: 
           [0011]      FIG. 1  is a representation of a portion of an exemplary filter house; 
           [0012]      FIG. 2  is a representation of an exemplary filter system in the filter house of  FIG. 1 ; 
           [0013]      FIG. 3  is another representation of an exemplary filter system in the filter house of  FIG. 1 ; 
           [0014]      FIG. 4  is a flow chart of a process for establishing an exemplary filter system; and 
           [0015]      FIG. 5  is a flow chart of a process for monitoring the exemplary filter system of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]      FIG. 1  illustrates an embodiment of a portion of filter house  100  wherein a first matrix of filter elements  102  is disposed on a tube sheet  103  to provide a first stage of air filtration. This first stage of air filtration may comprise a coarse filtration to remove larger particles from air passing through an air duct, such as conduit  107 , toward, for example, gas turbine compressors. The filter media  109  in the first stage filter elements  102  may be configured to admit finer particles while trapping coarser particles. Air that is filtered by the first stage filtration enters a first filter zone  101  wherein the air may be measured for various properties such as opacity, humidity and temperature. A second matrix of filter elements  104  is disposed on a tube sheet  103  to further filter air from the first filter zone  101 . This second stage of air filtration may comprise finer filter media  110  to remove smaller particles from the air that will pass into second filter zone  106  wherein the filtered air may again be measured for various properties, as described above. In the side view if  FIG. 1  one row each of filter elements  102 ,  104  are visible, however, multiple rows of filter elements  102  and  104  form the first matrix and the second matrix of filter elements on the tube sheets  103 , as described herein. Filtered air exits the second filter zone  106  and continues through conduit  107  in the direction indicated by the arrow  108 . The air is typically drawn through the filter house  100  by compressor suction at sufficient pressure to force incoming air through the two stages of filter elements. The matrix of filter elements  102 ,  104  are positioned on tube sheets  103  with sufficient pressure, such as provided by mechanical retainers, so as to divert air through the filter elements  102 ,  104  and to prevent gaps from forming between filter elements  102 ,  104  and the tube sheets  103  whereby dirty air might bypass the filter elements  102 ,  104  and continue traveling through the conduit  107 . 
         [0017]      FIG. 2  illustrates an embodiment of a filter system  200 , which may be located in a filter house such as illustrated in  FIG. 1 . The filter system  200  comprises a plurality of filter elements  202 , such as air filters, each disposed in a conduit  107 , which carries a gas, such as air, through the filter elements  202  in a direction indicated by the arrows  206 . The tube sheet  203  includes voltage lines  205 ,  210  connected to the voltage source  215 . The filter elements  202  each have a filter medium  109  or  110  for filtering air passing therethrough and an electrically conductive material portion  204  for connecting to the voltage lines  205 ,  210  when the filter elements  202  are in a properly installed position on the tube sheet  203 . The filter elements  202  are each properly installed in the conduit  107  at a mounting location  216  on the tube sheet  203  when the electrically conductive material portion  204  of the filter element  202  closes the electric circuit formed by voltage source  215  and voltage lines  205 ,  210 . 
         [0018]    The mounting locations  216  are each defined by an electrical contact, or electrical terminal, wherein the electrically conductive portions  204  of filter elements  202  may electrically contact the voltage lines  205 ,  210 . The mounting locations  216 , and the positioning of the electrically conductive material portion  204  on each filter element  202 , are selected such that when the circuit is closed by the filter element  202 , as just described, the filter element  202  is properly installed and provides an air tight seal against the tube sheet  203  of the conduit  107 . Therefore, any air traveling through conduit  107  has passed through the filter media  109  or  110  of properly installed filter elements  202  and cannot bypass the filter elements  202 . The mounting locations  216 , the electrically conductive material portions  204 , or the voltage lines  205 ,  210 , or a combination thereof, may comprise resistive elements to control an amount of current flowing therethrough. As described below, the resistive elements may be selectively sized in order to provide more precision in identifying failing filter elements  202 . 
         [0019]    The filter elements  202  are disposed on the tube sheet  103  in the conduit  107  for filtering particles from the air traveling through the conduit  107 . The air is typically drawn through the filter house by the compressor suction. As viewed in  FIG. 2 , the filter elements  202  in the upper portion of  FIG. 2  each comprise an electrically conductive material portion  204  that extends between two mounting locations  216 . Thus, there are two mounting locations  216  for each of these filter elements  202  which require their electrically conductive material portions  204  to contact the voltage lines  205 ,  210  at two corresponding electrical contact points. In the lower portion of  FIG. 2 , the filter elements  202  each comprise an electrically conductive material portion  204  that contacts one mounting location having spaced electrical contact points for closing the electrically conductive circuit with voltage lines  205 ,  210 . In one embodiment, the electrically conductive material portions  204  of each pair of the filter elements  202 , as seen in  FIG. 2 , are connected in parallel between voltage lines  205 ,  200 . The electrically conductive material portions  204  on the filter elements  202  may be variously formed and positioned, as shown in the embodiments of  FIG. 2 , from any conductive material in any form, such as a conductive coating, printed circuit, adhesive, wire, rod, tape, resistor, or other form, that is capable of reliably closing the electric circuit formed by voltage lines  205 ,  210  and voltage source  215 . 
         [0020]    As described above, such a closed electric circuit occurs when a filter element  202  is tightly sealed against tube sheet  203  such as may be accomplished by a mechanical retainer exerting a sufficient pressure upon the filter element  202 . Such a closed electric circuit will draw a small amount of electric current, and an open or closed electric circuit can be easily detected by electrical devices connected thereto. As described above, a resistive element may be introduced into the closed electric circuit, such as in the electrically conductive material portions  204 , in the voltage lines  205 ,  210 , or in the mounting locations  216 . Such resistive elements may include known resistances. An improperly installed, or dislodged, filter element  202  will alter electrical characteristics of its corresponding electric circuit which may be automatically detected by a monitoring detector  208  or control station  207 , as described below. These changed characteristics can be automatically, electrically detected without requiring manual or visual inspection of the installation of filter element  202 . Such changed characteristics include a different amount of current flowing through the voltage lines for a particular conduit and a different resistance presented by the electric circuit formed in a particular conduit. 
         [0021]    In one embodiment, detectors  208  are electrically connected to each of the closed circuits formed by voltage source  215 , voltage lines  205 ,  210 , and the electrically conductive material portion  204  of filter elements  202  that are properly secured at mounting locations  216  on the tube sheet  203 , through which a small current flows. If the circuit opens, such as by filter  202  becoming disengaged from its properly mounted position, the small current ceases flowing and this changed electrical characteristic is sensed by detector  208 . The detector  208  may include a visual indicator  209 , such as an LED, which can be configured to either illuminate or to turn off when the abnormal condition is sensed, depending on its standard default state. The detector  208  may include an audible indicator  214  which also can be configured for activation to indicate that the changed electrical characteristic is sensed. A plurality of detectors  208  can each be connected to the closed circuit formed at, or in proximity to, each filter  202  mounting location  216 , thereby providing a visual and/or audible notification when an air tight seal fails, with the added advantage of pointing out, by proximity to, the failing seal. 
         [0022]    In one embodiment, a control station  207  may be connected, via electrical lines  211 , as shown in  FIG. 2 , to all of the closed circuits formed by the filter elements  202  installed at mounting locations  216 . The control station  207  may include a display screen  212  and/or a speaker  213  for providing a visual and/or an audible notification upon detecting an open circuit caused by a failing seal. The control station  207  may include a microprocessor, or controller, with memory for storing programs executed by the microprocessor, as described herein, or for storing other information that is accessible by the microprocessor to perform monitoring tasks as described herein. The control station  207  may be located proximate to the filter system  200  or may be connected remotely by electrical lines  211 . The control station  207  may display information on display screen  212  identifying the filter element  202  whose seal is failing. The control station  207  may be embodied in a programmed computer, such as a personal computer, a tablet computer, a handheld processing system, a microcontroller, or some other programmed processing unit. The control station  207  may include a wireless communication capability for transmitting radio signal information to another remote processing unit for conveying status information about the filter system  200  or information about a detected failing seal. 
         [0023]    With reference to  FIG. 3 , there is illustrated an embodiment of a filter system  300 , similar to the embodiments of filter system  200  described and shown in  FIG. 2  except that several components are not depicted for purposes of clarity and ease of illustration. The embodiments illustrated in  FIG. 3  should be understood to be capable of implementing every feature of the filter system  200  as described in relation to  FIG. 2  above. As shown, filter system  300  may comprise any number of conduits  301 - 303  with any number of filter elements  321 - 329  installed therein. As illustrated, filter elements  321 - 323  are installed in corresponding conduit  301 ; filter elements  324 - 326  are installed in corresponding conduit  302 ; and filter elements  327 - 329  are installed in corresponding conduit  303 . The filter elements  321 - 329  comprise electrically conductive material portions  204  that are connected in parallel within each conduit  301 - 303  to voltage lines  205 ,  210 , so long as the filter elements  321 - 329  remain properly installed to provide air tight seals in the conduits  301 - 303 . Although not shown in  FIG. 3 , filter system  300  may include detectors such as the detectors  208  of  FIG. 2  that are operable in the same fashion as explained above with reference to  FIG. 2 . 
         [0024]    In one embodiment, voltage lines  205 ,  210  are all connected to the control station  207 . In this embodiment the control station  207  includes a voltage source connected to voltage lines  205 ,  210  for driving a small detectable current through the electrically conductive material portions  204  in filter elements  321 - 329 . The control station  207  further includes one or more digital ammeters or ohmmeters for monitoring the small amount of current flowing between voltage lines  205 ,  210  corresponding to each of the conduits  301 - 303  or for measuring a resistance of the electric circuit corresponding to each of the conduits  301 - 303 . If one of the filter elements  321 - 329  becomes dislodged, the failure is detected by the one or more digital ammeters or ohmmeters in control station  207  because the electrically conductive material portion  204  of the dislodged filter element  321 - 329  will be disconnected from either or both voltage lines  205 ,  210  and the total current flowing through, or the total resistance of, the remaining electrically conductive material portions  204  in the corresponding conduit  301 - 303  changes in an amount that can be detected by control station  207 . The expected current magnitude can easily be calculated at the control station processor using the well know electrical property I=V/R. In one embodiment the voltage level of the voltage source  215  is known, as well as the size of resistance elements in each closed circuit formed by installed filter elements  321 - 329 . 
         [0025]    The control station  207  may be configured by appropriate programming to store a selectable threshold current and/or resistance level and, in response to detecting that the current or resistance has changed and exceeds the threshold, to identify the corresponding conduit  301 - 303  where the change has occurred. Thus, in this embodiment, a dislodged filter element  321 - 329  can be more easily located by identifying the conduit  301 - 303  where the malfunction has occurred. 
         [0026]    The control station  207  may include a display screen  212  and/or a speaker  213  for providing a visual and/or an audible notification upon detecting the malfunctioning filter element  321 - 329 , such as a text message on display screen  212  or a pre-recorded audio replayed over speaker  213 . The control station  207  may be located proximate to the filter system  300  or it may be connected remotely by voltage lines  205 ,  210 . The control station  207  may be programmed to automatically display information on display screen  212  or to replay an audio message over speaker  213  identifying the corresponding conduit  301 - 303  having a filter element  321 - 329  whose seal has failed. The control station  207  may be embodied in a programmed computer, such as a personal computer, a tablet computer, a handheld processing system, a microcontroller, or some other programmed processing unit. The control station  207  may include a wireless communication capability for transmitting radio signal information to another remote processing unit for conveying information about one of the conduits  301 - 303  having a dislodged filter element  321 - 329 . 
         [0027]    In another embodiment, the resistances of the electrically conductive material portions  204  of filter elements  321 - 329  may be individually selected to provide known resistances to the voltage supplied by connected voltage lines  205 ,  210 . As a result, the expected current flowing through voltage lines  205 ,  210  for each conduit  301 - 303 , as well as a total resistance of each conduit  301 - 303 , can be calculated. Furthermore, the expected current magnitudes flowing through, and resistances of, voltage lines  205 ,  210  for each conduit  301 - 303  can be calculated for every possible combination of one or more failing filter elements  321 - 329 . By employing a different, known resistance for each of the electrically conductive material portions  204  within each conduit  301 - 303 , and recording the position of the known resistances corresponding to each filter element  321 - 329  location within the conduits  301 - 303 , the failing filter element can be pinpointed based on the numerical value of the decreased current flow. The failing filter element can also be pinpointed based on the numerical value of the remaining resistance provided by the known resistive elements connected in parallel. Thus, at least two electrical characteristics of each conduit can be used to determine whether a filter element has become dislodged and, if so, its location. 
         [0028]    As an illustrative example, if each of the electrically conductive material portions  204  of filter elements  321 - 323  in conduit  107  comprises a different preselected resistance element, and one of the filter elements  321 - 323  becomes dislodged, the decreased current level flowing through the remaining filter elements  321 - 323  can be calculated based on the voltage level of voltage lines  205 ,  210  and on the known resistances of the remaining parallel connected filter elements  321 - 323  in the conduit  107 . Because each filter element  321 - 323  will decrease the current level by a different amount if it becomes dislodged, a one-to-one correspondence between the numerical value of the decreased current level and each filter element  321 - 323  can be determined and stored in a table in a memory accessible by control station  207 . Similarly, such a table can be generated and stored which corresponds to the total resistance presented by the remaining filter elements. 
         [0029]    The control station  207  may be configured to store a table of expected current magnitudes, or resistance magnitudes, for each conduit  301 - 303  corresponding to possible combinations of one or more failing filter elements  321 - 329  together with locations of each of the filter elements  321 - 329 . Thus, the control station  207  may be programmed such that when a changed current or changed resistance is detected in one or more of the conduits  301 - 303  the conduit can be thereby identified, and the magnitude of the decreased current or resistance, as measured by the one or more digital ammeters and ohmmeters in control station  207 , can be looked up in the stored table to identify precisely which one or more filter elements  321 - 329  have failed and where they are located. 
         [0030]    As explained above with respect to  FIG. 2 , the electrically conductive material portions  204  on the filter elements  321 - 329  may be variously fabricated from any conductive material in any form, such as a conductive coating, printed circuit, adhesive, wire, rod, tape, resistor, or other form, that is capable of reliably electrically connecting to voltage lines  205 ,  210 . In addition, known resistors can be connected in line with the electrically conductive material portions  204 , in the mounting locations  216 , or in the voltage lines  205 ,  210 , to provide a known resistance corresponding to each filter element  321 - 329 . Such resistors can be directly attached to the filter elements  321 - 329  in their electrically conductive material portions  204  during manufacture of the filter elements  321 - 329 , or afterwards. 
         [0031]      FIG. 4  illustrates a method of implementing one embodiment wherein filter elements  202  are installed at mounting locations  216  on a tube sheet  203  and monitored to ensure that they are properly seated on the tube sheet  203 . In a first step, step  401 , a filter element  202  having an electrically conductive portion  204  is installed on a tube sheet  203  having voltage lines  205 ,  210  attached thereto at mounting locations  216 . The installation of the filter element  202  continues at step  402  wherein the electrically conductive portions  204  of the filter elements  202  are electrically connected to the voltage lines on the tube sheet  203 . This step may require that the filter element  202  be fastened to the tube sheet  203  using mechanical means such as retainers that will exert sufficient pressure so as to establish good electrical contact between the electrically conductive portion  204  on the filter element and the voltage lines  205 ,  210  on the tube sheet  203 . As described above, the voltage lines  205 ,  210  on the tube sheet  203 , as well as the electrically conductive portions  204  on the filter element  202 , may be variously fabricated from any conductive material in any form, such as a conductive coating, printed circuit, adhesive, wire, rod, tape, resistor, or other form, that is capable of reliably establishing electrical contact. After the electrical connections are established the corresponding circuits can be automatically monitored using a control station  207  or detector  208  as described above, in step  403 . The circuits are monitored for changes in electrical characteristics, such as resistance or current flow, and, when such changes are detected, the location of a filter element  202  is indicated by a detector  208  connected to the filter element  202  circuit or determined by a control station  207  connected to the filter element circuit, in step  404 . A magnitude of change in the electrical characteristics of a corresponding circuit is used to determine a location of a failing filter element  202  as described above. 
         [0032]      FIG. 5  illustrates, in the form of a flowchart, a method  500  performed by a control station  207  under programmed control to detect malfunctioning filter elements  321 - 329 . The control station  207  is programmed to monitor the current flowing through each conduit  301 - 303  of the filter system  300 , or the resistance of the circuit through each conduit, or a combination thereof, either continuously or periodically using the one or more digital ammeters, or ohmmeters, in the control station  207 , and to compare the monitored current level or resistance level with a stored numerical threshold value. At step  501 , the control station  207  detects that the current level or resistance level in one or more of the conduits  301 - 303  has changed. In response, at step  502 , the control station identifies the one or more conduits, either  301 ,  302 , or  303 , where the electrical characteristic has changed. At step  503 , the numerical value of the changed characteristic is looked up in an electronic table to identify a corresponding malfunctioning filter element  321 - 329 . The filter elements  321 - 329  are stored in the table each in association with the numerical values of various possible changed current and resistance levels for each conduit  301 - 303  based on all possible combinations of malfunctioning filter elements  321 - 329 . At step  504 , the control station  207  outputs information identifying the dislodged filter element  321 - 329  on its display screen  212 , through its speaker  213 , wirelessly over a radio channel to another processing unit, or a combination thereof. 
         [0033]    In view of the foregoing, embodiments of the invention provide a system and method for automatically detecting a disengaged filter element in a filter house. A technical effect is to increase mechanical performance and lifetimes of systems relying on a properly filtered air supply. 
         [0034]    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 “control station” “circuit,” “circuitry,” and/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. 
         [0035]    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. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, 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. 
         [0036]    Program code and/or executable instructions 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. 
         [0037]    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 such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The program code may execute entirely on the user&#39;s computer (device), 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). 
         [0038]    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. 
         [0039]    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. 
         [0040]    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. 
         [0041]    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.