Abstract:
A filter house and cleaning system arrangement for a turbine system and an associated method. The arrangement includes a filter house and filter elements within the filter house. The arrangement includes nozzles that spray a fluid on the filter elements to provide cleaning of the filter elements. The nozzles have structure that permits the nozzles to move within the filter house to adjust where on the filter elements the fluid is sprayed. The arrangement includes a detection device configured to detect a level of cleanliness and provide an output that indicates the level of cleanliness.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present application relates generally to gas turbine engines and more particularly relates to a filter washing system and method for use with a gas turbine air inlet and the like. 
         [0003]    2. Discussion of the Prior Art 
         [0004]    Air entering a turbine compressor inlet and similar devices should be filtered before compression or other use. Impure inlet air laden with dirt, debris, dust particles, salt, and other contaminants damage the compressor blades, plug cooling passages, and damage other types of power generation equipment via corrosion, erosion, fouling, and the like. Such damage may reduce the life expectancy and the overall performance of the generation equipment. To avoid this problem, the inlet air may pass through one or more filters to remove the entrained contaminants. 
         [0005]    The air filters, however, may have a relatively short life span due to accumulation of the dirt, debris, and other types of contaminants. This accumulation also may raise the pressure drop across the filter element. Raising the pressure drop reduces the overall airflow into the compressor, power output and the efficiency of the gas turbine engine. As such, the filter elements typically may be replaced when the pressure drop reaches the point in which the gas turbine operator deems the loss of machine efficiency exceeds the availability impact and costs associated with the replacing the filters. However, frequent filter replacement may result in high maintenance costs to the gas turbine end user in terms of labor and filters as well as the loss of revenue due to engine downtime and unavailability. Performing online filter replacement may result in premature wear of gas turbine compressor components and may be prohibited by safety regulations in some locations. 
         [0006]    To avoid the costs and problems associated with filter replacement, the filter elements are sometimes cleaned to remove the accumulation of the dirt, debris, and other types of contaminants. Known cleaning techniques include manually washing filter elements or providing a reverse blast of compressed air to the filter elements that creates a shock wave which knocks off the accumulated dirt, debris, and other contaminants. However, manual washing requires labor and is time consuming and compressed air cleaning techniques are sometimes not effective in cleaning dirt and debris located at the top of the filter elements. 
         [0007]    There is thus a need for an insitu filter element cleaning system that can effectively and efficiently remove the accumulation of dirt, debris, and other contaminants from the filter elements in an inlet air filter system. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0008]    The following presents a simplified summary of the invention in order to provide a basic understanding of some example aspects of the invention. This summary is not an extensive overview of the invention. Moreover, this summary is not intended to identify critical elements of the invention nor delineate the scope of the invention. The sole purpose of the summary is to present some concepts of the invention in simplified form as a prelude to the more detailed description that is presented later. 
         [0009]    In accordance with one aspect, the present invention provides a filter house and cleaning system arrangement for a turbine system. The arrangement includes a filter house, and filter elements and inlet cooling equipment within the filter house. The arrangement includes nozzles that spray a fluid on the filter elements to provide cleaning of the filter elements. The nozzles have structure that permits the nozzles to move within the filter house to adjust where on the filter elements the fluid is sprayed. The arrangement includes a detection device configured to detect a level of cleanliness and provide an output that indicates the level of cleanliness. 
         [0010]    In accordance with another aspect, the present invention provides a method for washing filter elements within a filter house for a turbine system. The method includes the steps of providing nozzles and spraying a fluid from the nozzles onto the filter elements. The method includes moving the nozzles within the filter house to adjust where on the filter elements the fluid is sprayed. The method includes detecting water leakage and carryover in the clean side. The method includes detecting a level of cleanliness and providing an output that indicates the level of cleanliness. In one specific example, the method includes utilization of a microprocessor based system with preprogrammed control logic to improve the effectiveness of washing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    These and other aspects are better understood when the following detailed description is read with reference to the accompanying drawings, in which: 
           [0012]      FIG. 1  is a schematic view of an example filter house and cleaning system arrangement for an example turbine system; 
           [0013]      FIG. 2  is a schematic view of some example details of the filter house and cleaning system arrangement; 
           [0014]      FIG. 3  schematically illustrates extension and retraction of a spray nozzle in an example embodiment of the cleaning system; 
           [0015]      FIG. 4  schematically illustrates rotation of a spray nozzle in an example embodiment of the cleaning system; 
           [0016]      FIG. 5  is a flow chart representing a beginning of an example cleaning sequence that may be performed using the cleaning system; 
           [0017]      FIG. 6  is a flow chart representing a chemical or normal wash cycle that may be performed during the example cleaning sequence; and 
           [0018]      FIG. 7  is a flow chart representing a rinse sequence that is performed during the example cleaning sequence. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    Example embodiments that incorporate one or more aspects of the present invention are described and illustrated in the drawings. These illustrated examples are not intended to be a limitation on the present invention. For example, one or more aspects of the present 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 present invention. Still further, in the drawings, the same reference numerals are employed for designating the same elements. 
         [0020]      FIG. 1  schematically shows an example filter house and cleaning system arrangement  8  in accordance with an aspect of the present invention. The arrangement  8  includes a cleaning system  10  for a filter house  12  of an example turbine system  14 . The shown example turbine system  14  includes a turbine engine  16  with a turbine  18  and a compressor  20 . The compressor  20  compresses an incoming flow of air for the turbine engine  16 . The mechanical work produced in the turbine  18  drives the compressor  20  along with external loads such as an electrical generator or the like. The turbine engine  16  may use natural gas, various types of syngas, and other types of fuels. The turbine engine  16  may have other configurations and may have types of components. Multiple turbine engines, other types of turbines, and other types of power generation may be used herein together. Of course, the turbine system  14  need not be a specific limitation upon the present invention. 
         [0021]    The filter house  12  may be positioned adjacent to an inlet of the compressor  20 , or other type of air inlet system, to filter inlet air. As schematically shown in  FIG. 2 , the filter house  12  may be bounded by a housing  24 . The filter house  12  includes a number of filter elements  26 . The filter elements  26  may have a variety of constructions and/or configurations, such as being pleated or non-pleated. As another possible variant, the filter elements  26  may include a hydrophobic and/or an oleophobic filter media therein. The filter media may be a web of synthetic fibers. The filter media may include PFTE (Polytetrafluoroethylene), ePFTE (Expanded Polytetrafluoroethylene), and similar types of materials. Examples of filter elements with a hydrophobic and/or a oleophobic filter media include a F9 MH filter sold by General Electric Company of Schenectady, N.Y., a Duravee HXL 98 Filter sold by AAF International of Louisville, Ky., and a D-Salt filter sold by Donaldson Company, Inc. of Minneapolis, Minn., and similar types of filter elements and hydrophobic or oleophobic filter media. 
         [0022]    The filter elements  26  may extend from a wall  28  of the housing  24  or some other surface within the housing  24 . The filter elements  26  may be arranged in the form of a grid and each of the filter elements  26  may be inclined to promote fluid drainage. The filter house  12  is configured such that inlet air enters the filter house  12  and passes through the filter elements  26  before exiting the filter house  12  and entering the inlet of the turbine engine  16 . As the inlet air passes through the filter elements  26 , the filter media traps dirt, debris, dust particles, salt, or other contaminants within the inlet air. The space upstream of the filter elements  26  thus becomes the dirty side  32  of the filter elements  26  while the space downstream of the filter elements  26  becomes the clean side  34  of the filter elements  26 . 
         [0023]    The filter house  12  may be divided into multiple decks. For instance, as shown in  FIG. 2 , the filter house  12  may be divided into a top/upper deck  36  and a bottom/lower deck  38 . Each deck may include one or more filter elements. Moreover, although two filter decks are shown in  FIG. 2 , there may be other example filter houses which are divided into more than two decks. Additionally, the filter house  12  may be divided into multiple filter banks. For example, the filter house  12  may be configured such that the air passes through a pre-filter bank followed by a final filter bank. Moreover, the filter house  12  may be configured to include more than two filter banks. It is to be appreciated that the construction/configuration of the filters, the multiple decks, and/or the multiple banks may be varied and need not be specific limitations upon the present invention. 
         [0024]    Turning to the cleaning system  10 , the cleaning system  10  includes a washing system  40 . As schematically shown in  FIG. 2 , the washing system  40  can spray a washing fluid  44  into the filter house  12  and onto the filter elements  26  to remove accumulated dirt, debris, and other contaminants from the filter elements  26 . The washing fluid  44  may be chilled below ambient temperature, at ambient temperature, or above ambient temperature. The washing fluid  44  may be water, a chemical solution comprising water and a cleaning agent, or another cleaning fluid. The water of the washing fluid  44  may be clean, demineralized water or pH neutral water. The cleaning agent may be a known detergent or some other cleaning product. The washing fluid  44  composition may depend on the area of the filter house  12  being sprayed, the contaminants present in the environment, the media type of the filter elements  26  in use, and/or other factors. 
         [0025]    Also shown in  FIG. 2 , the washing system  40  includes a number of spray nozzles  46  to direct the washing fluid  44  within the filter house  12 . Any number of spray nozzles  46  may be used. The spray nozzles  46  may be positioned between the filter elements  26  and along the same wall  28  from which the filter elements  26  extend. However, the spray nozzles  46  may be located elsewhere. For example, the spray nozzles  46  may be located across from, above, or below the filter elements  26 . The spray nozzles  46  may also be attached to other surfaces within the housing  24 . 
         [0026]    Each spray nozzle  46  may be moveable within the filter housing  24 . For example, each spray nozzle  46  may extend into or retract from the interior  48  of the filter housing  24  as schematically represented in  FIG. 3  via a double arrowhead. Each spray nozzle may also be constructed/configured to rotate as schematically represented in  FIG. 4  via an arrow headed arc. It is contemplated that each nozzle may be constructed/configured to have other, different movements. Such movements allow a single spray nozzle to direct washing fluid  44  toward various locations along one or more filter elements  26 . Moreover, the spray nozzles  46  may be oriented to direct the washing fluid  44  toward other portions of the filter house  12  such as the filter housing walls, bird screens, and trays. 
         [0027]    Returning to  FIG. 2 , the washing system  40  may include a water tank  52  to store the washing fluid  44 . If the washing system  40  uses a chemical solution, the washing system  40  may also include a separate cleaning agent tank  54  to store the cleaning agent. A separate mixing chamber  56  can be provided to mix a ratio of the water and cleaning agent within. The washing system  40  may include washing fluid distribution piping  58  to provide fluid communication between the spray nozzles  46 , water tank  52 , and mixing chamber  56 . Moreover, the washing system  40  may include pumps  62  to distribute/transfer the water from the tank  52  and the cleaning agent from the tank  54 , respectively, into the mixing chamber  56 . In turn the mixed washing fluid  44  from mixing chamber  56  is delivered to the spray nozzles  46  via the washing fluid distribution piping  58 . 
         [0028]    It is to be appreciated that the relative amounts of the cleaning agent and the water being supplied to the mixing chamber  56  at any particular time can be varied via varied operation of the two pumps  62 . As such, various operation scenarios are possible. For example, it is possible to initially only supply water to the mixing chamber  56 . As such, only water is delivered to the spray nozzles  46  via the washing fluid distribution piping  58 . Subsequently it is possible to supply both cleaning agent and the water to the mixing chamber  56 . As such the mixed cleaning agent and water delivered to the spray nozzles  46  via the washing fluid distribution piping  58 . At a further subsequent time, it is possible to again only supply water to the mixing chamber  56 . As such, only water is delivered to the spray nozzles  46  via the washing fluid distribution piping  58 . So within the presented example a sequence of water only, water and cleaning agent, and water only is provided. 
         [0029]    The washing system  40  may also be equipped with one or more sensors. For example, as shown in  FIG. 2 , the water and cleaning agent tanks  52 ,  54  may include level sensors  64  to detect how much water and cleaning agent is available for use. The washing system  40  may also include one or more pressure sensors  66  or flow sensors  68  in the washing fluid distribution piping  58  to ensure that the pump  62  is operating correctly and that the spray nozzles  46  are receiving sufficient washing fluid  44 . 
         [0030]    Within one example embodiment, the washing system  40  will preferably wash the filter elements  26  in sequence from the top deck  36  to the bottom deck  38  to ensure that the lower filter elements  26  will not be washed first and then be contaminated with runoff from the filter elements  26  located above. For example, the spray nozzles  46  may be moved/oriented to direct washing fluid  44  toward the top deck  36  filter elements  26  first. The spray nozzles  46  may then be moved/oriented to direct washing fluid  44  towards the lower filter elements  26 . Additionally, the washing fluid distribution piping  58  may include control members, such as solenoid valves  70 , which can be opened or closed to control which spray nozzles  46  receive washing fluid  44 . As such, control members (e.g., solenoid valves  70 ) can dictate which spray nozzles  46  will spray washing fluid  44  and thus which filter elements  26  will be washed. Accordingly, the washing system  40  can wash the filter elements  26  in a top deck  36  to bottom deck  38  sequence through movement of the spray nozzles  46 , control of the solenoid valves  70 , or some combination thereof. Moreover, the washing system  40  may be capable of other sequences. For example, the washing system  40  may wash the filter elements  26  from pre filter bank to final filter bank or vice versa. The washing system  40  may also wash the filter elements  26  simultaneously in no particular sequence. The washing system will also have the capability to wash any other installed components inside the filter house such as chiller coils etc. 
         [0031]    Returning to  FIG. 1 , the cleaning system  10  may also include a pulse air system  72  to deliver compressed air to the filter elements  26 . As shown in  FIG. 2 , the pulse air system  72  may include an air piping system  74  which transfers compressed air from an air compressor  76  to a number of air nozzles  78 . Preferably, the air nozzles  78  will direct the compressed air to the filter elements  26  in a direction that is reverse to the direction of travel for the inlet air. For example, as shown in  FIG. 2 , compressed air is applied to the clean side  34  of the filter elements  26 . The compressed air then travels through the filter elements  26  to the dirty side  32  of filter elements  26 . 
         [0032]    A blast of compressed air may be used to create a shock wave which can knock accumulated dirt, debris, or other contaminants off of the filter elements  26 . Additionally, the compressed air may also be used to dry the filter elements  26 . For example, after the washing system  40  sprays the filter elements  26 , the pulse air system  72  can be activated to remove any residual cleaning fluid that remains on the filter elements  26 . In another embodiment, the pulse air could be heated to supply warm air to dry the filter elements. 
         [0033]    Similar to the washing system  40 , the pulse air system  72  can spray the air nozzles  78  in a sequence such that the compressed air is applied to the filter elements  26  from the top deck  36  to the bottom deck  38 . However, the air nozzles  78  may be sprayed simultaneously or in some alternative sequence. 
         [0034]    The cleaning system  10  may further include a drain box  80  in fluid communication with the filter house  12 . As shown in  FIG. 2 , the example filter house  12  includes a runoff drain  84  that receives runoff fluid from the washing system  40 . The drain box  80  can be connected into the runoff drain  84  to collect the runoff fluid. A drain valve may be located between the drain box  80  and the runoff drain  84  to permit or limit fluid communication between the drain box  80  and the runoff drain  84 . Additionally, a floor of the filter house  12  may be sloped to assist in directing the runoff fluid towards the runoff drain  84  and into the drain box  80 . 
         [0035]    The drain box  80  may be equipped with a flow sensor and/or a level sensor  86  to ensure that there is not a buildup of washing fluid  44  in the filter house  12  due to blockage, as shown in  FIG. 1 . Additionally, the drain box  80  may be tied into a hazardous waste drain system  90  so that the runoff fluid can be safely collected and disposed of. There may also be additional valves located between the drain box  80  and the hazardous waste drain system  90  to permit or limit fluid communication between the drain box  80  and the hazardous waste drain system  90 . 
         [0036]    If the filter house  12  is divided into multiple decks, each deck may have its own runoff drain, sloped floor, drain valve, or combination thereof. If multiple runoff drains are present, there may be a separate drain box for each runoff drain. Alternatively, each runoff drain may tie into the same drain box or there may be one runoff drain that collects runoff fluid from the remaining runoff drains and feeds the runoff fluid into a drain box. 
         [0037]    The cleaning system  10  may also include a detection device to detect the quality of filter cleaning achieved and provide an output that indicates the level of cleanliness. For example,  FIG. 1  schematically shows that a conductivity analyzer  92  may be used to detect the number of residual contaminants that are present in the runoff fluid that collects in the drain box  80 . A high level of residual contaminants present in the runoff fluid will indicate that the filter elements  26  are in need of further cleaning. Although the detection device of the present embodiment analyzes runoff water in the drain box  80 , other locations may be analyzed to determine the quality of the filter cleaning achieved. For example, the detection device could analyze runoff water in the runoff drain  84  or in the piping which runs between the runoff drain  84 , drain box  80 , and hazardous waste drain system  90 . 
         [0038]    Additionally, other devices or methods other than a conductivity analyzer  92  may be used to detect the quality of filter cleaning achieved. For example, pH indicators or clarity/turbidity sensors may be used or a visual inspection of the filter elements  26  or runoff fluid may be performed. 
         [0039]    As shown in  FIG. 1 , the cleaning system  10  may also include a microprocessor based control system  94  as a means for controlling the cleaning system  10 . One or more elements of the cleaning system  10  may be in communication with the control system  94 . For example, the control system  94  may be in communication with the pulse air system  72 , the washing system  40 , drain valves, level sensors  64  and  86 , flow sensors  68 , conductivity analyzers  92 , or any combination thereof. Additionally, the control system  94  may include one or more alarms or timers. For example, the control system  94  may include an alarm that will activate when there is an insufficient amount of water available in the water tank  52  for a cleaning sequence. Also, the control system  94  may include a timer so that the washing system  40  will only spray washing fluid  44  into the filter house  12  for a limited time. 
         [0040]    The control system  94  can be interfaced with turbine control systems and other plant control systems  96 . The control system  94  may also include an interface or panel to allow plant personnel to interact with the control system  94  and operate the cleaning system  10 . Accordingly, the control system  94  can provide the ability to operate one or more elements of the cleaning system  10  in a cleaning sequence  100 . 
         [0041]    The cleaning system  10  described above can be operated manually, automatically, or in some combination thereof. In one specific example, the cleaning system  10  will be operated while the turbine engine  16  is shut down or on turning gear. However, there may be elements of the cleaning system  10  which operate while the turbine engine  16  is in operation. 
         [0042]      FIGS. 5-7  provide flowcharts which together illustrate an example cleaning sequence  100  that may be performed using the cleaning system  10  described above. As shown in  FIG. 5 , the example cleaning sequence  100  begins with the step  102  of determining if the turbine engine  16  is on turning gear (e.g., a low-speed operation). If the turbine engine  16  is in operation, an alarm  104  within the control system  94  will activate and the sequence will not proceed forward. However, if the turbine engine  16  is on turning gear, an operator may then start the wash cycle in step  106 . It should be appreciated that although the present example requires the turbine engine  16  to be on turning gear before starting the wash cycle, there may be other example sequences in which the wash cycle is allowed to start while the turbine is shut down or in operation. 
         [0043]    In step  106 , the operator starts the wash cycle by selecting “WASH” on an interface or panel. The operator may also have the option to select which type of wash cycle will be performed. For example, the operator may select a chemical wash that uses a solution of water and a cleaning agent as its washing fluid  44 . Alternatively, the operator may select a normal wash which will only use water as its cleaning fluid. 
         [0044]    If multiple filter banks are present, an operator may also have an option to select which banks are to be washed. For example, an operator may have the option to select “ALL”, “PRE” or “FINAL” (“ALL”—both filter banks, “PRE”—pre filter bank, “FINAL”—final filter bank). If less than all of the filter banks are selected for washing, the steps hereinafter will only pertain to the filter banks that were selected for washing. 
         [0045]    The example cleaning sequence  100  further includes step  108 , wherein the pulse air system  72  delivers pulse air to the filter house  12  to dislodge large particles and agitate any caked material adhering to the outside of the filter elements  26 . The drain valve is then opened in step  110  to permit fluid communication between the runoff drain  84  and drain box  80 . Although the example sequence illustrated in  FIG. 5  shows that the drain valve is opened after the delivery of pulse air, the drain valve may be opened during or even before the delivery of pulse air. In fact, the drain valve may be opened at any point before cleaning fluid is sprayed into the filter house  12 . 
         [0046]    The subsequent steps in the example cleaning sequence  100  vary depending on the type of wash cycle that is selected by the operator.  FIG. 6  shows the chemical or normal wash cycle for the example cleaning sequence  100 . 
         [0047]    The chemical wash cycle begins with the step  114  of determining if there is a sufficient amount of cleaning agent available for the chemical wash cycle. The chemical wash cycle also includes the step  116  of determining if there is a sufficient amount of water available for the chemical wash cycle. These levels may be determined with level sensors  64  in the water tank  52  and cleaning agent tank  54 , as shown in  FIG. 2 . If either amount is insufficient, an alarm  118 ,  120  will activate within the control system  94  and the sequence will stop. Although the flowchart in  FIG. 6  shows that the cleaning agent level is determined first, it should be appreciated that the water level may be determined before the cleaning agent level. 
         [0048]    The chemical wash cycle further includes step  124 , wherein a ratio of water and the cleaning agent is mixed. The ratio may depend on the area of the filter house  12  being sprayed, the contaminants present in the environment, the media type of the filter elements  26  in use, and/or other factors. Once the ratio of the mixture is imputed—in manual mode-, the control system  94  will activate the pumps  62  in step  126  and verify that the proper valves are open or closed in the washing fluid distribution piping  58  for washing. In automatic mode the system will activate the pumps  62  and create the wash solution based on the programmed predetermined ratio and verify that the proper valves are open or closed in the washing fluid distribution piping  58  for washing. The operator would also be free to choose the mixing proportion or the controller will determine optimum ratio based on predetermined parameters and feedback from the system. 
         [0049]    Once the pump  62  is activated, the cleaning system  10  will begin spraying the solution into the filter house  12 . The control system  94  will verify that the pump motors are running and that the discharge pressures and flow of the solution are sufficient, as represented by steps  128 ,  130 , and  132 . If the discharge pressures or flow of the solution are insufficient or if the pump motors are not running, an alarm will activate. Otherwise, the cleaning system  10  will spray the solution into the filter house  12  on a timer-based sequence, as represented by step  140 . For example, the control system  94  can sequence the spraying so that the filter elements  26  are washed from the top deck  36  to the bottom deck  38 . The control system  94  can use timers to control how long each deck is sprayed with the solution. 
         [0050]    For the normal wash cycle, water may be used as a washing fluid  44  without adding a cleaning agent. As such, the step  114  of determining the level of cleaning agent is unnecessary. Instead, normal wash cycle begins with the step  116  of determining if there is a sufficient amount of water available for the normal wash cycle. If the amount of water is insufficient, an alarm  120  will activate within the control system  94  and the sequence will stop. If the amount is sufficient, the control system  94  will activate the pump  62  and verify valve positions in step  126 . 
         [0051]    Once the pump  62  is activated, the cleaning system  10  will begin spraying water into the filter house  12 . The control system  94  will verify that the pump motors are running and that the discharge pressures and flow of the water are sufficient, as represented by steps  128 ,  130 , and  132 . If the discharge pressures or flow of the water are insufficient or if the pump motors are not running, an alarm will activate. Otherwise, the cleaning system  10  will spray the water into the filter house  12  on a timer-based sequence, as represented by step  140 . For example, the control system  94  can sequence the spraying so that the filter elements  26  are washed from the top deck  36  to the bottom deck  38 . The control system  94  may use timers to control how long each deck is sprayed with the water. 
         [0052]      FIG. 7  shows the rinse sequence portion of the example cleaning sequence  100 . The rinse sequence follows the wash cycle and begins with the step  144  of confirming that the drain valve is opened and that there is a sufficient amount of rinse water available. The rinse water may come from the same water tank  52  as the water that is used for the wash cycle or the rinse water may come from a different source. Once it is confirmed that the drain valve is opened and there is sufficient amount of rinse water available, the rinse cycle will start in step  146 . During the rinse cycle, rinse water is sprayed through the spray nozzles  46  into the filter house  12 . Similar to the wash cycle, the cleaning system  10  can spray the rinse water into the filter house  12  on a timer-based sequence. For example, the control system  94  can sequence the spraying so that the filter elements  26  are rinsed from the top deck  36  to the bottom deck  38 . The control system  94  can use timers to control how long each deck is sprayed with the rinse water. 
         [0053]    Once the rinse cycle is complete, the cleaning system  10  will detect the quality of cleaning in step  148  and determine if the quality of cleaning is acceptable in step  150 . This can be accomplished using a detection device such as a conductivity analyzer or turbidity sensor  92 . The conductivity analyzer  92  can detect the quality of cleaning and provide an output to the control system  94  which indicates the level of cleanliness. If the quality of cleaning is unacceptable, an alarm  152  within the control system  94  will activate and the rinse cycle can either be manually or automatically reactivated. Steps  148  and  150  are then repeated to determine if the rinse cycle will be reactivated any further. 
         [0054]    Once the quality of cleaning is acceptable, the pulse air system  72  will activate in step  154  to dry out the filter elements  26  and remove any residual water. The drain valve will then close to prohibit fluid communication between the runoff drain  84  and drain box  80 , as represented by step  156 . The example cleaning sequence  100  is then complete. 
         [0055]    A continuous check is also carried out to detect any water leakage or carryover on the clean side. Water boxes are provided and the cleaning cycle is stopped. 
         [0056]    It should be apparent that the foregoing relates only to certain embodiments of the present application and that numerous changes and modifications may be made herein by one of ordinary skill in the art without departing from the general spirit and scope of the invention as defined by the following claims and equivalents thereof.