Patent Publication Number: US-2012037005-A1

Title: Filter integrity monitoring system

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates generally to a filtration system, and more particularly, to a filtration system that can provide an indication of a filtration media defect. 
     2. Discussion of Prior Art 
     Filter elements may be used to provide clean fluid, such as air, to or from various devices. Such devices may include gas turbines. Filter elements contain filtration media, and the filter elements are in various forms such as panels or other configurations. Also, the filter elements are planar or contoured, such as pleated or the like. The filter elements are used singularly and are also used as part of arrays, such as within filter houses. The particular characteristics, composition, etc. of the filtration media within the filter elements are varied to correspond to the type of filtering to be performed, the particulate matter being filtered, etc. 
     In order for a filter element within a filter element to provide a desired filtering effect, the filtration media needs to be in serviceable condition. One condition that may result in filtration media not being in serviceable condition is a media defect, such as a hole, a tear, a seal defect, or the like. Such a defect would permit unwanted particulate matter passing the filtration media at the location of the defect. 
     It is possible to try to determine whether the filtration media within a filter element has a defect. A rudimentary approach is to attempt to locate defects via visual inspection. However, such an approach may require interruption of operation of the filtering and/or the device (i.e., a turbine) associated with the filtering. Also, such an approach may require that the filter element be removed for inspection or otherwise accessed by the person conducting the inspection. Such a rudimentary approach of course has some disadvantages, including man-power needs and operation down-time. 
     There are also more sophisticated systems/methods that have been used to try to determine whether the filtration media within a filter element has a defect. For example, WO2007GB0003325 discloses a system that monitors the filtration media integrity by using downstream and upstream probes and by counting particulate matter. As another example, EP1760292A2 discloses a system that monitors the particulate count across a downstream duct. A variation of particle concentration indicates a filtration media defect failure. As a third example, JP2006009591A2 discloses a system that compares an upstream pressure versus a downstream pressure to determine a differential. 
     The previous sophisticated systems/methods mentioned above, may have issues related to the sophistication present therein, such as sensor equipment costs, calibration, and the like. Also, it may be difficult to for such sophisticated systems/methods to provide an indication of the location of a defect within the filtration media. Such an issue would logically become more apparent upon increases in the size of a filter element and/or the number of filter elements. 
     In general, there are benefits for continual improvements in filter monitoring technologies so as to address these and other issues. Specifically, there are benefits to seeking an approach that provide a cost-effective indication of a filtration media defect and which can also provide an indication of the location of the defect. 
     Also, the system within which a filter element is utilized may induce a pattern of fluid flow such that flow through a filter element is significantly unbalanced. For example, a significant amount of flow may pass though only one portion (e.g., one-half) of the filter. In general, this can be conceded to be aerodynamic issues. The filter element itself may be defect-free. However, it could be considered that such a scenario does not effectively and efficiently utilize the filter element. Such a scenario may result in a filter element may be replaced at a time different (e.g., shorter or longer) that the normal recommended replacement time interval. 
     There are benefits for identifying aerodynamic issues at a filter element. For example, adjustments could be made to more effectively and efficiently utilize the filter element. 
     BRIEF DESCRIPTION OF THE INVENTION 
     The following summary presents a simplified summary in order to provide a basic understanding of some aspects discussed herein. This summary is not an extensive overview of the invention discussed herein. It is not intended to identify key/critical elements or to delineate the scope of such invention. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later. 
     In accordance with one aspect, the present invention provides a system for fluid filtration and for providing an indication of filtration operation. The system includes a filtration media for permitting flow of fluid there through and for filtering at least one material from the fluid. The filtration media has an upstream side and a downstream side. The system includes a member located adjacent to the downstream side of the filtration media and permitting flow of the fluid there through. The member retains at least some of the at least one material not filtered from the fluid by the filtration media. The member is contrast to the at least one material so that an indication of locality of reduced filtration of the at least one material is provided. 
     In accordance with another aspect, the present invention provides a system for fluid filtration and for providing an indication of filtration operation. The system uses a filtration media for permitting flow of fluid there through and for filtering at least one material from the fluid. The filtration media has an upstream side and a downstream side. The system includes a member located adjacent to the downstream side of the filtration media and permitting flow of the fluid there through. The member retains at least some of the at least one material not filtered from the fluid by the filtration media. The member is contrast to the at least one material so that an indication of locality of reduced filtration of the at least one material is provided. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other aspects of the invention will become apparent to those skilled in the art to which the invention relates upon reading the following description with reference to the accompanying drawings, in which: 
         FIG. 1  is a schematic illustration of an example fluid filtration system that includes an aspect in accordance with the present invention; 
         FIG. 2  is schematized perspective view of a portion of the system shown in  FIG. 1  and includes a fresh, example filter element and a fresh, example indicator member located adjacent to the filter element; 
         FIG. 3  is a view similar to  FIG. 2 , but shows a typical time-progressed contrast accumulation upon the indicator member after an amount of typical filtration has occurred at the filter element; 
         FIG. 4  is a view similar to  FIG. 2 , but shows that the filter element has a defect and shows a contrast indication upon the indicator member; and 
         FIG. 5  is a view similar to  FIG. 2 , but the filter is subjected to an aerodynamic issue such that most fluid flows through a lower portion of the filter element and a contrast indication is located as a lower portion of the indication member. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Example embodiments that incorporate one or more aspects of the invention are described and illustrated in the drawings. These illustrated examples are not intended to be a limitation on the invention. For example, one or more aspects of the invention can be utilized in other embodiments and even other types of devices. Moreover, certain terminology is used herein for convenience only and is not to be taken as a limitation on the invention. Still further, in the drawings, the same reference numerals are employed for designating the same elements. 
       FIG. 1  schematically illustrates an example of a system  10  for fluid filtration and for providing and indication of filtration operation. The system  10  may be part of an overall larger arrangement, such as a gas turbine compressor. The specific overall arrangement within which the system is incorporated need not be a specific limitation upon the present invention. 
     In general, a flow of fluid  12  (generically represented by the arrowhead) proceeds from a source  14  of fluid, along a path defined by surrounding conveyance structure  16 , is directed through a filter element  18 , and proceeds to a filtered fluid utilization component  20 . Logically, the filter element  18  has an upstream side and a down stream side. 
     The fluid may be air. However, other fluids (e.g., other gases besides air) may be filtered and the specific fluid being filtered may not be a specific limitation upon the invention. The fluid proceeding from the source  14  of fluid contains material  24  (only some generic material shown) that is to be filtered from the fluid via the filter element  18 . The material  24  to be filtered may be particulate matter (e.g., dust). Also the source  14  of fluid may be varied. Specifically, the source  14  of fluid may be the ambient atmosphere, and thus the material  24  to be filtered from the fluid may be material that is airborne within atmospheric air. As another example, the source  14  of fluid may be a component that produces the fluid-borne material  24  (e.g., ash), with the fluid-borne material (e.g., ash) to be removed from the fluid. As such, the source  14  of fluid is to be broadly interpreted. It to be appreciated that the filtered fluid utilization component  20  may be varied. One example of the filtered fluid utilization component  20  is a turbine. Also the filtered fluid utilization component  20  may be another device (e.g., an engine) that utilizes a filtered fluid. Still further, the filtered fluid utilization component  20  may even be as basic as a clean air return to ambient atmosphere. As such, the filtered fluid utilization component  20  should be broadly interpreted. 
     The schematic drawing of  FIG. 1  shows the components arranged at/with the conveyance structure in relatively close proximity, in a straight/linear arrangement, and in a left to right sequence. However, the example system  10  shown in  FIG. 1  is merely a schematic representation of an aspect of the invention and is not a specific limitation upon the present invention. Certainly it is to be appreciated that variations in dimensions, orientations, etc. are within the scope of the invention. 
     The filter element  18  includes a filtration media  30  that filters the material  24  (e.g., particulate matter) from the fluid. The filtration media  30  permits flow of fluid there through and filters at least one material  24  from the fluid. The filtration media  30  has an upstream side and a downstream side, with the material  24  tending to accumulate upon the upstream side during the filtering process. 
     Logically, the filtration media  30  is matched to the material  24  to be filtered. As such, the filtration media  30  has particular characteristics, composition, etc. that correspond to the type of filtering to be performed, the material  24  being filtered, etc., and such characteristics, composition, etc. may not be limitations upon the present invention. The filter element  18  may be provided in a variety of forms, such as a panel or other configurations. Also, the filter element  18  may be planar or contoured, such as pleated, shaped (e.g., bag) or the like. The filter element  18  may be used singularly or may also used as part of an array, such as within a filter house. So it is to be appreciated that the specific material to be filtered, the specifics of the filter element(s), and the specifics of the filtration media of the filter element(s) need not be specific limitations upon the present invention. 
     In order for the filtration media  30  within a filter element  18  to provide a desired filtering effect, the filtration media needs to be in serviceable condition. One condition that may result in filtration media not being in serviceable condition is a media defect  40  (an example defect is shown in  FIG. 1 ), such as a hole, a tear, a seal defect, or the like. Such a defect  40  would permit unwanted material  24  (e.g., particulate matter) to pass the filtration media  30  at the location of the defect. As such, the defect  40  is an example of a locality of reduced filtration of the at least one material  24 . 
     Also, in order for the filter element  18  to provide the filtering function with good efficiency and/or with good life-cycle, the overall area of the filtration media  30  should be effectively utilized. One example of effective utilization of the filtration media  30  occurs when filtered material accumulates over the entire overall area of the filtration media in a generally uniform distribution. 
     In accordance with an aspect of the present invention, an indicator member  50  (highly schematized in  FIG. 1 ) is located adjacent to a downstream side of the filtration media  30  of the filter element  18  and permitting flow of the fluid there through. The indicator member  50  retains at least some of the at least one material  24  not filtered from the fluid by the filtration media  30 . The indicator member  50  has a contrast to the at least one material  24  so that visual indication of locality of reduced filtration of the at least one material is provided. It should be appreciated that distance from the downstream side of the filtration media  30  to the indicator member  50  may be varied. 
     The indicator member  50  may have a variety of configurations. For example, the indicator member  50  may have a peripheral frame, with a mesh or grid that extends across the flow path of the fluid proceeding from the fluid. The indicator member  50  may itself provide some level of filtering function since it is intended that at least some of the material  24  that is within the fluid is to be retained upon the member. However, the function in accordance with an aspect of the present invention is that at least some material  24  that passes the filtration media  30  of the filter element  18  is retained on the member at a location on the member that generally corresponds to a location on the filtration media through which the material passed. As such, if a relatively large amount of material  24  is passing through the filtration media  30  at a specific location, a correspondingly large amount of the material  24  will be retained upon the indicator member  50  at the corresponding location on the indicator member  50 . 
     Turing to the aspect of the indicator member  50  having a contrast as compared to the material  24  being filtered, a variety of contract aspects could be present/utilized. For example, if the material  24  being filtered is dark, the indicator member  50  (e.g., the mesh or strands) is light. As another example, if the material  24  being filtered is light, the indicator member  50  (e.g., the mesh or strands) is dark. These are examples of contrast of shade. As another example, if the material  24  being filtered is one color, the indicator member  50  is a different, contrasting color. Still further examples, contrast may be in other manners, such as florescence vs. non-florescence, infrared vs. non-infrared (e.g., spectral), and the like. It is to be appreciated that other types of contrast are possible and are within the scope of the present invention such that the listed types of contrast need not be specific limitations upon the present invention. 
     Turning to  FIG. 2 , an example of the filter element  18  and the indicator member  50  is shown. It is to be appreciated that the filter element  18  is shown with contouring (e.g., pleats). Also, the filter element  18  is shown as a plurality (e.g., bank) of discrete filters. In this example, the indicator member  50  is a light colored member and the material  24  (e.g., particulate) being filtered is dark. In  FIG. 2 , the indicator member  50  is fresh in that no material  24  has proceeded past the filter element  18  and been retained upon the indicator member  50 . The arrowhead  12  generically represents the flow of the fluid through the filter element  18  and the indicator member  50 . 
       FIG. 3  shows a time-progressed situation for the circumstance of a typical filter element operation. During the operation, some material  24  will proceed past the filter element  18 . At least some material  24  is retained upon the indicator member  50 . The retained material  24  is a contrast (e.g., dark upon light), so that the retained material can be perceived (e.g., seen). The retained material  24  is generically represented by the random flecks upon the indicator member  50 . The size of the flecks is enlarged for illustrative purpose. It should be appreciated that the shown size, orientation, etc. of the material  24  are not limitations upon the present invention. Also, it is to be appreciated that the material  24  is retained (e.g., impinged upon) the side of the indicator member  50  facing the filter element  18 , which can be considered to be an upstream side. The retained material  24  may be observed from the upstream side or the down stream side if the indicator member  50  is sufficiently transparent/translucent. In view of the fact that the operation is typical in  FIG. 3 , fluid flow, and thus passed material  24 , is uniformly distributed. Specifically, the material  24  is uniformly distributed within the flow and thus uniformly distributed upon the indicator member  50 . This uniform distribution upon the indicator member  50  is an indication of uniform distribution upon the filter element  18 . 
     Focusing again upon  FIG. 1 , an example of defect (e.g., a hole)  40  is provided in the filtration media  30  and also an example trajectory cone of travel  56  for material (e.g., particulate matter)  24  proceeding through the defect  40  in the filtration media  30  is provided. It is to be appreciated that an amount of material  24  passing the filter element  18  at the defect  40  will be greater than amounts of material  24  passing the filter element  18  at other, non-defect areas. It should be appreciated that the trajectory cone of travel  56  for material  24  proceeding through the defect  40  in the filtration media  30  will result in a greater amount of material  24  impinging upon and thus being retained upon the indicator member  50  at a location. Herein, the location of greater retention can be referred to as a spot of material  24  (e.g., a material spot). If the material  24  is dust, the material spot can be considered to be a dust spot. 
       FIG. 4  shows an example of a material (e.g., dust) spot  60  on the indicator member  50  which resulted from the presence of a defect  40  in the filtration media  30 . It should be noted that the shown material spot  60  is present on an otherwise “clean” indicator member  50 . It is to be appreciated that such presentation is merely for illustration of the concept. It is also possible for the entire indicator member  50  to have at least some level of material retention, but with the material spot  60  being of greater intensity/density of retained material  24  as compared to the other areas of the indicator member. 
     The location of the material spot  60  on the indicator member  50  has a correspondence with the defect  40  in the filter element  18 . An example of this concept is presented via the trajectory cone of travel  56  within  FIG. 1 . The correspondence may be a relatively straight line of flight between the filter defect  40  location and the material spot  60  on the indicator member  50 . Of course, there may be a different type of correspondence. However, the existence of a correspondence is useful to help identify the presence and location of the filter defect  40 . 
     It is possible that other types of undesirable, inefficient, or similar circumstances can be detected/determined in accordance with other aspects of the present invention. For example, attention is directed to  FIG. 5  which shows an indicator member  50  having material  24  primarily collected on a lower portion  70  of the member. This may be indicative of a majority of the fluid flow proceeding through the lower portion  70 . Such a condition would suggest that a similar majority of the fluid flow proceeding through only a portion (e.g., a lower portion) of the filter element  18 . The locality of reduced filtration is located at an area different from an area through which a majority of the fluid flow proceeds and the locality of reduced filtration causes a difference in contrast on the member  50  in comparison to the area through which a majority of the fluid flow proceeds. 
     Such a circumstance indicates that the filter element  18  may not be utilized in an efficient manner. With such information provided by an indication upon the indicator member  50 , it may be possible to take some corrective efforts to cause the fluid flow to more evenly proceed through the filter element  18 . 
     Turning now to a process of evaluating accumulation of material upon the member, it should be appreciated that various techniques, methods, structures, etc. may be employed. As one example it is to be appreciated that the indicator member  50  may be viewed by an unaided human eye. It is possible the indicator member  50  could be displaced and/or removed for periodic inspection. As another variation, the structure  16  containing the fluid flow could be configured (e.g., use of a clear panel) to permit visual observation while the indicator member  50  is in place and the fluid is flowing (i.e., operational). 
     As yet another example, a remote viewing arrangement may be utilized. A schematic example of such is shown in each of  FIGS. 2-5 . Specifically, a camera  80  is provided, with the camera for obtaining an image of the indicator member  50 . The image(s) may be stored for later use, comparison, remote viewing, and the like. Associated with the camera is an illumination source (e.g., a light source)  90 . Of course, the type, position, number, etc. of the camera  80  and/or illumination source  90  may be varied. Also, the camera  80  and/or illumination source  90  may be related to the type of material  24  to be filtered. For example, if the material is florescent, associated spectral illumination/camera may be utilized. 
     The invention has been described with reference to the example embodiments described above. Modifications and alterations will occur to others upon a reading and understanding of this specification. Example embodiments incorporating one or more aspects of the invention are intended to include all such modifications and alterations insofar as they come within the scope of the appended claims.