Abstract:
This disclosure proposes a new structure for pre-filter devices, and filtration systems in general, that facilitates tasks necessary to maintain performance of pre-filter banks in the filtration system. Embodiments of this structure allow the pre-filter devices to translate on corresponding structural members that make up the supporting structure of the pre-filter bank. When in position, the proposed pre-filter devices can mate with adjacent pre-filter devices to form a substantially unitary structure that prohibits fluid from flowing unfiltered to areas downstream of the filtration system.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The subject matter disclosed herein relates to filters and filtration of fluids and, in one particular implementation, to filtration that occurs in power systems (e.g., gas turbines). 
         [0002]    Filtration systems prevent damage that particles can cause to the components in various applications, e.g., gas turbine systems, heating, ventilation, and air conditioning (HVAC) systems, etc. Many filtration systems pass fluid through one or more filter banks and, more particularly, through a pre-filter bank and a final filter bank. The pre-filter bank includes filter devices (also “pre-filter devices”) with filter media that can capture large particles. This filter media, and the pre-filter bank generally, is in place to pro-long the lifespan of the final filter bank, which incorporates filter devices (also “final filter devices”) with filter media of much finer porosity. This finer filter media can clog or become inoperable as a result of impact from particles of large size during operation, e.g. of a gas turbine. 
         [0003]    Because the pre-filter devices are subject to more, and larger, particulates, these devices tend to degrade at a much faster rate than the final filter devices. Degraded filters can disrupt fluid flow, thereby increasing the pressure drop through the filtration system. These problems can adversely affect the performance of the system in which the filtration system is used. For example, substantial pressure drops in the filtration system may reduce efficiency and, ultimately, the output of a gas turbine. 
         [0004]    Routine maintenance to timely replace the pre-filter devices can address performance of the pre-filter bank. In many cases, scheduled maintenance requires technicians to unfasten the degraded pre-filter devices from the supporting structure and to secure new pre-filter devices in place. But although simple in its description, the maintenance steps can prove costly because pre-filter banks in many filtration systems require hundreds of pre-filter devices that reside in supporting structures that are several stories tall. Thus, the scope of maintenance requires an extensive investment in time, materials, and labor, not to mention costs associated with non-productive downtime of the particular machinery (e.g., gas turbine) on which the maintenance occurs. 
         [0005]    Improvements to facilitate maintenance of the pre-filter bank focus on design features to simplify the fastening and unfastening of the filter devices to the supporting structure. These design features do not, however, address any of the other tasks (e.g., lifting and moving the new and degraded pre-filters) that are necessary to completely outfit the pre-filter banks with new pre-filter devices. For example, in addition to the number of pre-filter devices that must be replaced, the physical characteristics (e.g., size and weight) of the pre-filters in both new and degraded condition further compound the difficulties technicians experience when they perform maintenance tasks on pre-filter banks 
         [0006]    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 
       [0007]    This disclosure proposes a new structure for pre-filter devices, and filtration systems in general, that facilitates tasks necessary to maintain performance of pre-filter banks in the filtration system. Embodiments of this structure allow the pre-filter devices to translate on corresponding structural members that make up the supporting structure of the pre-filter bank. When in position, the proposed pre-filter devices can mate with adjacent pre-filter devices to form a substantially unitary structure that prohibits fluid from flowing unfiltered to areas downstream of the filtration system. 
         [0008]    This disclosure describes, in one embodiment, a filter frame that includes a frame having an upstream side and a downstream side. The frame bounds a filter receiving area and forms an opening on the upstream side to receive a filter element into the filter receiving area. In one example, the frame includes a protruding element that extends radially away from the filter receiving area. The filter frame also includes a transitory assembly coupled with the filter frame. The transitory assembly has a transitory element disposed on the downstream side of the filter frame. 
         [0009]    This disclosure also describes, in one embodiment, a filter frame that includes a frame with an upstream side and a downstream side. The frame includes frame members forming a peripheral boundary to a filter receiving area in which a filter element can reside. The frame member have a protruding element that extends radially away from the filter receiving area. The protruding element has a downstream face that is set off from the downstream side on one or more of the frame members. The filter frame also includes a transitory element coupled with the frame and spaced interior to the peripheral boundary. 
         [0010]    This disclosure further describes, in one embodiment, a method for replacing filter devices in a filtration system that has a filter housing and a system structure disposed in the filter housing. The system structure supports the filter devices. The method includes steps for translating a first filter device from a first position to a second position that is laterally offset from the first position in the system structure. The method also includes steps for removing the first filter device from the filtration system at the second position and translating a second filter device to the second position. The method further includes steps for removing the second filter device from the filtration system at the second position. 
         [0011]    This brief description of the invention is intended only to provide a brief overview of the 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 
         [0012]    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: 
           [0013]      FIG. 1  depicts a schematic diagram of a side view of an exemplary embodiment of a filter device in a filtration system for use in one application, e.g., a gas turbine system. 
           [0014]      FIG. 2  depicts a perspective view of the filtration system of  FIG. 1 ; 
           [0015]      FIG. 3  depicts a perspective view of an exemplary embodiment of a filter device in exploded assembly form; 
           [0016]      FIG. 4  depicts the filter frame of  FIG. 3 ; 
           [0017]      FIG. 5  depicts a side view of the filter device of  FIG. 3  in assembled form; 
           [0018]      FIG. 6  depicts a back view of an exemplary arrangement of filter devices (e.g., the filter device of  FIGS. 3 and 4 ); 
           [0019]      FIG. 7  depicts a perspective view of an exemplary filtration system; 
           [0020]      FIG. 8  depicts a top view of the exemplary filtration system of  FIG. 6 ; and 
           [0021]      FIG. 9  depicts a flow diagram of a method for performing maintenance on a filtration system, e.g., filtration system of  FIGS. 7 and 8 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]      FIG. 1  depicts a schematic diagram that illustrates an exemplary embodiment of a filter device  100  that can remove particulates and debris from a fluid F. The filter device  100  is part of a filtration system  102  with a filter housing  104  that surrounds a support structure  106 . For purposes of the present discussion, the filtration system  102  resides in a power generating system  108  that includes an inlet hood structure  110 , ducting  112 , and a power source  114  (e.g., a gas turbine). This disclosure also contemplates examples of the filtration system  102  that find use with other types of systems that also require filtration to remove particulates from fluids that pass through the system. 
         [0023]    The diagram of  FIG. 2  depicts a perspective view to focus the discussion on the filtration system  102 . In one example, the filtration system  102  includes a plurality of filter devices (e.g., a first filter device  116 , a second filter device  118 , a third filter device  120 , and a fourth filter device  122 ) that make up an array or filter bank  124 . The filter devices  116 ,  118 ,  120 ,  122  can translate laterally within the filter bank  124 , as shown generally by the arrow identified by  126 . This features allows the filter devices  116 ,  118 ,  120 ,  122  to traverse the support structure  106  among a variety of positions within the filter bank  124 . These positions can include a first position that mates horizontally adjacent filter devices (e.g., the filter device  120  and the filter device  122 ) and vertically adjacent filter devices (e.g., the filter device  116  and the filter device  120 ). The positions can also include a second position at which at least one of the filter devices (e.g., the filter device  118 ) is spaced apart and/or separated from one of the other filter devices (e.g., the filter device  116 ). 
         [0024]    Mating of the filter devices  116 ,  118 ,  120 ,  122  can prevent fluid F from penetrating through the filter bank  124  to areas downstream of the filtration system  102 . As set forth more below, the proposed structures for the filter devices  116 ,  118 ,  120 ,  122  can incorporate elements that create a barrier to the flow of fluid F in the first position. This feature ensures filtration of the incoming fluid F by, for example, providing only one path for the fluid F to traverse the filter bank  124 , i.e., through the filter media and/or area of the filter devices  116 ,  118 ,  120 ,  122 . Moreover, in one example, the proposed structure can also engage one another to secure the filter devices  116 ,  118 ,  120 ,  122  without the need for fasteners (e.g., bolts, screws, clips, etc) that require unfastening during repair and maintenance. 
         [0025]    Examples of proposed filter devices also work in conjunction with the support structure  106  to maintain the position and structural integrity of the filter bank  124  with the flexibility to translate the filter devices as desired. For example, elements on the filter devices and on the support structure can permit rolling and/or low-friction sliding of the filter devices  116 ,  118 ,  120 ,  122 . This design eliminates the need to lift and extract the filter devices from individual locations within the filter bank  124 . On the other hand, this disclosure contemplates designs that allow the filter devices to translate to and from a central location, e.g., one end of the support structure  106 . To facilitate movement, the configuration may incorporate an actuator assembly (e.g., a motor and pulley) that imparts force onto the filter devices. For purposes of removing the filter devices from the filter bank  124 , the actuator assembly can impart a force that moves the filter devices toward the central location. A technician can extract the filter devices in sequence (e.g., the filter device  118  first, then the filter device  116  second, etc) at the central location. Often, the extraction process can occur without the need to move from location-to-location within the filter bank  124 . To install new filter devices, the technician can insert the new filter devices into the filter bank one at a time (e.g., the filter device  116  first, then the filter device  118  second, etc.). In one example, each successive filter device translates or “pushes” the prior-installed filter devices into position within the filter bank  124 . When in use, the actuator assembly can impart a force that moves the filter devices into position in the filter bank  124 . 
         [0026]      FIG. 3  depicts a perspective, exploded assembly view of an exemplary embodiment of a filter device  200  that can remove particulates and debris from a fluid F. The filter device  200  has an upstream side  202  and a downstream side  204 , the orientation of which depends on the direction of flow of the fluid F. As shown in  FIG. 3 , the filter device  200  includes a filter element  206  and a support element  208  that align on a longitudinal axis  210 . The filter element  206  may include a filter media that filters the fluid F as the fluid F passes through the filter media from the upstream side  202  to the downstream side  204 . 
         [0027]    The support element  208  includes a filter frame  212  that forms a filter receiving area  214 . The filter frame  212  has an opening and/or aperture on the upstream side  202  to allow the filter element  206  to insert into the filter receiving area  214 . On the downstream side  204 , the support element  208  also includes a transitory assembly that secures with the filter frame  212 . The transitory assembly facilitates motion of the filter device  200  when, in one implementation, the filter device  200  is in position, e.g., as part of a filtration system (e.g., filtration system  102  of  FIGS. 1 and 2 ). The transitory assembly includes one or more transitory elements  216  that provide rolling and/or sliding translation. In one example, the transitory elements  216  are spaced interior of the filter frame  212 , e.g., in the path of fluid F that passes through the filter element  206 . In one example, the transitory assembly also includes one or more downstream frame members (e.g., a first downstream frame member  218  and a second downstream frame member  220 ) that can receive the transitory elements  216  thereon. Examples of the frame members  218 ,  220  span across the flow path of the fluid F from one side of the peripheral frame  212  to the other. In one example, the frame members  218 ,  220  position the transitory elements  216  to engage structure of a filtration system (e.g., filtration system  102  of  FIGS. 1 and 2 ) that allows the filter device  200  to translate among various positions. 
         [0028]    With reference to  FIG. 4 , the filter frame  212  can include a plurality of frame members (e.g., a first frame member  222 , a second frame member  224 , a third frame member  226 , and a fourth frame member  228 ) that form, respectively, a top side, a bottom side, a first side, and a second side of the filter frame  212 . In one example, the frame members  222 ,  224 ,  226 ,  228  form a first pair of frame members  222 ,  224  that share a first common corner  230  and a second pair of frame members  226 ,  228  that share a second common corner  232 . 
         [0029]    The frame members  222 ,  224 ,  226 ,  228  have a body  234  that forms a protruding element  236  that extends radially away from the filter receiving area  214 . In one example, the protruding element  236  circumscribes the periphery of the filter frame  212 , forming a single, contiguous structure and/or separate structures (as shown in  FIG. 4 ). The protruding element  236  has a downstream face  238  that is setoff from the downstream side  204  of the frame members  222 ,  224 ,  226 ,  228  on one or more of the top side, the bottom side, the first side, and the second side. 
         [0030]    The filter frame  212  affords the filter device  200  with structural stiffness and stability. Examples of the filter frame  212  can comprise metals and high-strength plastics, although any variety of materials may be compatible with the structure and function of the filter device  200 . In one example, one or more of the frame members  222 ,  224 ,  226 ,  228  are constructed unitarily, e.g., as a single and/or monolithic unit that can receive the filter element  206  therein. Other examples may require that one or more structural members are formed separately. These individual pieces can comport with assembly using any variety of fasteners (e.g., bolts and screws), adhesives, and welds. 
         [0031]    In addition to the “L-shape” illustrated in  FIGS. 3 and 4  (and  FIGS. 5 ,  6 , and  7  below) the body  234  can embody other shapes that retain and/or incorporate the features and functions of the protruding element  236 . These shapes include “Z-shapes” in which the body  234  may include an additional part or portion that extends relatively inwardly toward the interior of the filter frame  212  and in the direction of the longitudinal axis  210 . The Z-shape may provide an inner surface that can engage part of the filter element  206  at the peripheral edges to prevent translation of the filter element  206  through the second side. 
         [0032]    For purposes of securing the filter element  206  within the peripheral frame  212 , one or more of the frame members  222 ,  224 ,  226 ,  228  can include a retention feature that can engage the filter element  206 . This retention feature may utilize one or more fasteners (e.g., a screw) that engage the filter element  206  and the peripheral frame  212 . More elaborate designs that utilize snaps, clasps, other similar, moveable elements may also reside on the peripheral frame  212  to engage the filter element  206  and secure the filter element  206  in position. 
         [0033]    Exemplary devices for use as the transitory elements  216  provide sliding, rolling, and/or low-friction engagement with the support structure of the filtration system. These devices may include rollers, castors, bearings, and similar devices that secure in position on the filter frame  212 . These devices can secure, in one example, to the downstream frame members  218 ,  220  allowing rotation about an axis to facilitate translation (e.g., from the first position to the second position of  FIG. 2 ). In one embodiment, the transitory elements  216  may comprise low friction materials (e.g., thermoplastics) that provide minimal sliding resistance in lieu of rotation. In still other embodiments, the filter frame  212  may incorporate low-friction materials and/or rolling element devices that can facilitate movement as discussed herein. 
         [0034]      FIG. 5  illustrates a side view of the filter device  200  in assembled form to discuss the setoff of the protruding element  236 . As shown in  FIG. 4 , the filter frame  212  can have an exposed surface or face  240  that forms a plane  242  on the downstream side  204  of the filter device  200 . The protruding elements  236  on the first frame member  222  and the second frame member  224  has a first setoff from the plane  242  in a direction towards the upstream side  202 . The protruding element  236  on the third frame member  226  (and, although not shown, the fourth frame member  228  ( FIG. 4 ) can have a second set off, which in the present example is effective zero (i.e., the downstream face  238  on the third frame member  226  (and the fourth frame member  228 ) is effectively flush and/or planar with the plane  242 ). 
         [0035]    Arranging the protruding elements  236 , e.g., with the setoff of the downstream face  238 , on the frame members  222 ,  224 ,  226 ,  228  allows filter devices (e.g., filter device  100 ,  200 ) to mate and interlock with adjacent filter devices (e.g., filter devices  100 ,  200 ) in the filter bank (e.g., filter bank  124  of  FIGS. 1 and 2 ). Moreover, this construction does not necessitate multiple different constructions for the peripheral frame  212 . Rather, the filter frame  212  can be oriented in various orientations to position the protruding element  236  to allow the necessary engagement of the adjacent filter devices in the filter bank. 
         [0036]    In one embodiment, the protruding element  236  may include an engagement element that cooperates with adjacent filter devices in the filter bank to secure the filter devices together. Examples of this engagement element can couple and decouple, e.g., in response to an input force that meets and/or exceeds the threshold retention force of the engagement element. In one example, the engagement element may comprise a lip and/or protrusion that is disposed on the protruding element  236 . The engagement element can have one or more lead-in surfaces that allow the adjacent filter devices to ride up and over the engagement element under sufficient input force. 
         [0037]      FIG. 6  depicts a back (or downstream) view of one arrangement of a plurality of filter devices  300  as would be found in a filtration system (e.g., filtration system  102  of  FIGS. 1 and 2 ). In the example of  FIG. 6 , the arrangement includes a first filter device  302 , a second filter device  304 , a third filter device  306 , and a fourth filter device  308 . This arrangement creates one or more areas of engagement (e.g., a first area  310  and a second area  312 ). In these areas, the filter frames (e.g., a first filter frame  314 , a second filter frame  316 , a third filter frame  318 , and a fourth filter frame  320 ) of adjacent filter devices meet and/or mate together. The configuration of the first area  310  and the second area  312  blocks (and/or prohibits) the flow of the fluid F ( FIGS. 1 ,  2 ,  3 , and  4 ) in between the filter devices  302 ,  304 ,  306 ,  308 . This feature ensures the flow of the fluid F through the filter element (e.g., filter element  208  of  FIGS. 3 and 4 ), thereby preventing unfiltered air from downstream of the filter devices  302 ,  304 ,  306 ,  308 . 
         [0038]      FIG. 7  shows a perspective view of one implementation of filter devices  400  as part of a filtration system  402 . The filtration system  402  includes a system structure with one or more upright members (e.g., a first upright member  404  and a second upright member  406 ) and horizontal channels (e.g., a first channel  408 , a second channel  410 , a third channel  412 , and a forth channel  414 ). In one embodiment, the filtration system  402  includes an actuator assembly  416  with an actuator  418  and connecting member  420 , the combination of which can causes one or more of the filter devices  400  to translate, e.g., along the channel members  408 ,  410 ,  412 ,  414 . 
         [0039]    As best shown in  FIG. 8 , which is a top view of the filtration system  402  in a filter housing (e.g., a filter housing  104  of  FIG. 1 ) with opposing side walls (e.g., a first side wall  422  and a second side wall  424 ). The position of the filtration system  402  in the filter housing may form a gap  426  or space between one of the side walls  422 ,  424  and the outer upright members  404 ,  406 . A cover element  428  found in the gap  426  in lieu of a filter device (e.g., filter devices  100 ,  200 ,  300 ,  400 ) can prevent the flow of fluid F through the gap  426 . Examples of the cover element  428  may be the same size as the filter device (e.g., filter devices  100 ,  200 ,  300 ,  400 ) and/or may extend the entire height of the system structure. During maintenance, the technician can remove the cover element  428  to establish the gap  426 . In one example, the gap  426  is sized to allow the technician to remove the filter devices  400  from the system structure and to position new filter devices to slide into the system structure as set forth herein. 
         [0040]      FIG. 9  illustrates a flow diagram of a method  500  for performing maintenance on a filtration system (e.g., filtration system  402  of  FIGS. 7 and 8 ). The method  500  includes, at step  502 , translating a first filter device from a first position to a second position. The method  500  also includes, at step  504 , removing the first filter device from the filtration system. The method  500  further includes, at step  506 , translating a second filter device to the second position and, at step  508 , removing the second filter device from the filtration system. 
         [0041]    Embodiments of the method  500  are useful to remove and replace the filter devices from the system structure in the filtration system. As set forth above, for example, the system structure can arrange filter device in a grid. Translating a first filter device (e.g., at step  502 ) can move one of the first filter devices to the gap and/or space from which the technician can remove the filter device from the structure. The technician can repeat this step to continue to remove the filter devices, until in one example all of the filter devices in one row of the grid are removed. The technician can slide one or more filter devices into the grid, wherein consecutive filter devices can abut one another to apply the sliding force and move the filter devices laterally across the grid. This process can be used, for example, to remove used, dirty filters from the grid and to insert unused, clean filters into the grid. In one embodiment, the method  500  can include steps for operating an actuator assembly coupled to one or more of the first filter device and the second filter device and for consecutively inserting a third filter device into the support structure and a fourth filter device into the support structure, wherein the third filter device and the fourth filter device translate laterally from the second position into the support structure. 
         [0042]    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. 
         [0043]    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.