Abstract:
A method, including receiving a turbine filter unit in a plasma treatment system, wherein the turbine filter unit comprises a filter media assembled with a framework, and applying at least one plasma treatment coating to the turbine filter unit via the plasma treatment system.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The subject matter disclosed herein relates to filters, and more particularly to filters treated with plasma. 
         [0002]    A gas turbine engine combusts a fuel-air mixture to generate hot combustion gases, which drive rotation of turbine blades in a turbine section. The gas turbine engine may be used to drive an electrical generator or another load. The gas turbine engine intakes air through an air filter, which removes particulate to protect internal components of the gas turbine engine. Unfortunately, existing air filters may be inadequate for certain environmental conditions, such as heavy fog, dust/sand storms, and other harsh conditions. An inadequate air filter may cause operational problems for the turbine, such as, unforeseen shutdown or increased performance degradation. Thus, under such harsh conditions, the installed air filter would require replacement with another more suitable air filter, thereby resulting in waste of the installed air filter. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0003]    Certain embodiments commensurate in scope with the originally claimed invention are summarized below. These embodiments are not intended to limit the scope of the claimed invention, but rather these embodiments are intended only to provide a brief summary of possible forms of the invention. Indeed, the invention may encompass a variety of forms that may be similar to or different from the embodiments set forth below. 
         [0004]    In a first embodiment, a method includes receiving a turbine filter unit in a plasma treatment system, wherein the turbine filter unit comprises a filter media assembled with a framework, and applying at least one plasma treatment coating to the turbine filter unit via the plasma treatment system. 
         [0005]    In a second embodiment, a method includes receiving a prefabricated turbine filter unit in a plasma treatment system, and applying at least one plasma treatment coating to the prefabricated turbine filter unit via the plasma treatment system, wherein the at least one plasma treatment coating provides a moisture barrier to protect a gas turbine engine from moisture in an air intake. 
         [0006]    In a third embodiment, a system includes a turbine filter unit including a filter media assembled with a framework, wherein the turbine filter unit includes at least one plasma treatment coating disposed over the filter media and the framework, and the at least one plasma treatment coating provides a moisture barrier to protect a gas turbine engine from moisture in an air intake. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein: 
           [0008]      FIG. 1  is a perspective view of an embodiment of a power generation facility with plasma treated turbine air filters; 
           [0009]      FIG. 2  is a perspective view of an embodiment of the filter frame of  FIG. 1  with plasma treated turbine air filters; 
           [0010]      FIG. 3  is a block diagram of an embodiment illustrating a plasma treatment system for treating a gas turbine air filter; 
           [0011]      FIG. 4  is a flow chart illustrating an embodiment of a process for plasma treating a gas turbine air filter; 
           [0012]      FIG. 5  is a cross-sectional side view of an embodiment of a plasma treated turbine air filter; 
           [0013]      FIG. 6  is a cross-sectional side view of an embodiment of a plasma treated turbine air filter; and 
           [0014]      FIG. 7  is a cross-sectional side view of an embodiment of a plasma treated turbine air filter with multiple coatings. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0015]    One or more specific embodiments of the present invention will be described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. 
         [0016]    When introducing elements of various embodiments of the present invention, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. 
         [0017]    The present disclosure is directed to turbine filters that are plasma treated post fabrication. In other words, the turbine filters may be substantially or completely covered with a plasma coating, which may extend over both filter media and non-filter media (e.g., frame). For example, a turbine filter may be purchased from a supplier and then treated with a plasma coating to enhance certain properties. By further example, the plasma coating may be applied on site and/or in response to site-specific environmental conditions, thereby converting an off the shelf turbine filter into a custom turbine filter rather than scrapping the filter. The plasma coating may be a common coating applied to all air filters, or an application specific coating helpful in specific types of environments. For example, the plasma coating may be a hydrophobic coating, a hydrophilic coating, or a combination thereof. In some embodiments, a filter may have a hydrophobic coating on a first side of a filter and a hydrophilic coating on a second side of a filter. In still other embodiments, the filter may include multiple coatings one on top of the other. Although the plasma treated filters are discussed in context of gas turbine engines, the disclosed plasma coating of an off the shelf filter may be supplied to any type of filters in any industry. 
         [0018]      FIG. 1  is a perspective view of an embodiment of a power generation facility  10  that uses plasma treated filters  11 . The power generation facility  10  includes a gas turbine engine  12  that generates electrical power. The turbine engine  12  includes an air compressor  14  that draws intake air  16  into the turbine engine  12  from the outdoors through air ducts  18 . As the intake air  16  enters the facility, it first passes through a filter house  20 . Inside the filter house  20 , an array of filters  11 , held by one or more filter frames  22 , filter the intake air  16  to remove contaminants such as dust, dirt, moisture, salt, carbon and any other contaminants that may tend to reduce the performance of the turbine  12 . The filter house  20  may be several stories high, and may house up to several hundred filters  11 , which may be held by several filter frames  22 . As discussed below, each filter  11  may be plasma treated after fabrication, e.g., on-site or in response to site-specific environment conditions. 
         [0019]      FIG. 2  is a perspective view illustrating an embodiment of the filter frame  22  of  FIG. 1 . As shown in  FIG. 2 , the filter frame  22  includes a set of vertical support panels  26  and horizontal support panels  28  that define filter cells  30 . The vertical support panels  26  and horizontal support panels  28  serve, in part, as dividers between the filter cells  30 , each of which holds a single plasma treated air filter  11 . Each filter cell  30  may include an aperture  32  through which the filter  11  may pass, and a sealing face  34  against which the filter  11  may be pressed to block air from flowing around the filter  11 . The filter  11  may include a filter body  46  that passes through the aperture  32  and a sealing flange  44  disposed about the rim of the outward face  36  of the filter body  46 . The sealing flange  44  may be configured to fit inside the filter cell  30  and may be pressed against the sealing face  34 . A gasket may be disposed between the sealing face  34  and the filter flange  44  to provide an airtight seal between the filter  11  and the sealing face  34 . 
         [0020]    The filters  11  may be any suitable type, such as bag filters or mini-pleat filters, pulse cartridge filters for example. In some embodiments, the filters  11  may be high-efficiency AltairSupernova™ filters, available from General Electric of Schenectady, N.Y. Additionally, the filters  11  may also be any suitable size. For example, in some embodiments, the filter height  38  and width  40  may be approximate 600 mm, the filter depth  42  may be approximately 400 to 500 millimeters, and each filter  11  may weight approximately 15 kilograms. Additionally, in some embodiments, the filter cells  30  and/or the filter frame  22  may provide suitable drainage for moisture, which may collect on the outside of the filter  11 . Also included in the filter frame  22  are several fasteners or latches  48 , which hold the filters  11  within the frame and provide sufficient compression to the sealing flange  44  to provide the airtight seal between the filter  11  and the sealing face  34 . Again, as discussed below, each filter  11  may include one or more plasma coatings (e.g., applied post fabrication) extending over both the filter media and non-filter media, such as the sealing flange  44 , framework, support structure, or other non-filter element. 
         [0021]      FIG. 3  is a block diagram of an embodiment illustrating a plasma treatment system  70 . The plasma treatment system  70  includes a chamber  72 , gas valve  74 , venting valve  76 , vacuum pump  78 , process gas  80 , electrode  82 , high frequency generator  84 , controller  86 , and frame  88 . The plasma treatment system  70  may employ various steps to coat the filter  11 . In the illustrated embodiment, controller  86  signals the vacuum pump  78  to evacuate the chamber  72 , creating a threshold low-pressure condition in the chamber  72 . Upon reaching a low-pressure condition, the controller  86  turns off the vacuum pump  78 . After reaching the low-pressure condition, the controller  86  opens valve  74  to feed process gas  80  into the chamber  72 , until reaching a working pressure. After reaching the working pressure, the controller  86  turns on the high frequency generator  84  that energizes the electrode  82 . The electrode  82  ionizes the process gas  80  to create plasma, which then deposits on the filter  11  as a plasma coating. For example, the process gas  80  may be a plasma monomer that undergoes reactions and then deposits on the surface of the air filter  11  as a polymer. The type of monomer and the processing parameters will determine the resulting surface property (e.g., hydrophobic, hydrophilic, etc.). As the gas ionizes and deposits on the filter  11 , the controller  86  activates the vacuum pump  78  removing the contaminated gas, while process gas  80  continuously enters container  72 . Finally, after plasma coating the filter  11 , the controller  86  closes valve  74  and turns off the high frequency generator  84 . The controller  86  then opens valve  76  to vent the chamber  72  of process gas  80 . 
         [0022]    As illustrated, the system  70  includes a frame  88 . The frame  88  allows for the plasma coating of different portions of the filter  11  with the same or a different plasma coating. For example, the frame  88  permits plasma coating of the outward face  36  while isolating the body  46  from the plasma. Similarly, after plasma coating the outward face  36 , the filter  11  may be rotated in the frame  88  and the body  46  coated with the same or a different plasma coating, while isolating the outward face  36 . In this manner, the outward face  36  and the body  46  may be treated with the same/different plasma coating. 
         [0023]      FIG. 4  is a flow chart illustrating an embodiment of a process  110  for plasma treating a gas turbine air filter  11 . The process  110  begins by receiving a turbine filter  11  in a plasma treatment system (block  112 ). Once inside the plasma treatment system, a first plasma treatment coating is applied to the filter  11  (block  114 ). After applying the first plasma treatment, a second plasma treatment may be applied (block  116 ). Depending on the embodiment, the first plasma treatment coating may differ from the second plasma treatment coating. In embodiments with different plasma treatment coatings, the first and second plasma treatment coatings may be applied to the same region or different regions of the filter  11 . For example, the plasma treatment coatings may be applied to upstream and downstream sides of the filter  11 . In certain embodiments, the first region may be masked while applying the second plasma treatment coating to the second region, and the second region may be masked while applying the first plasma treatment coating to the first region. However, any suitable process may be used to apply one or more plasma treatment coatings. Furthermore, the coatings may differ in thickness, properties, materials, or a combination thereof. The application of different coatings will be discussed in detail below. 
         [0024]      FIG. 5  is a cross-sectional side view of an embodiment of a plasma treated turbine air filter  11 . The filter  11  defines a front face  122  (upstream or intake side), a rear face  124  (downstream or exhaust side), a first frame portion  126 , and a second frame portion  128 . Covering the front face  122  is a first plasma coating  130  and covering the rear face  124  is a second plasma coating  132 . As illustrated, the coatings  130  and  132  extend over the first and second frame portions  126  and  128 , which may be a single structure or separate structure. Depending on the embodiment, the first plasma coating  130  may be the same as or different from the second plasma coating  132 . These plasma coatings may provide a moisture barrier, increase strength, wear resistance, or abrasion resistance in adverse environmental conditions (e.g., sandstorm, hail storm, or wind storm), increase resistance to corrosive environments (e.g., salt water), or any combination thereof. For example, the first plasma coating  130  may be hydrophobic, while the second plasma coating  132  is hydrophilic. As a result, the first plasma coating  130  (hydrophobic) blocks or repels water from passing through the filter  11 , while the second plasma coating  132  (hydrophilic) absorbs water not repelled by the first plasma coating  130 . The water absorbed by the hydrophilic coating  132  may then drain out of the filter  11  using gravity. Thus, filter  11  coated with two different plasma coatings may effectively reduce the amount of moisture that enters a gas turbine  12 , by simultaneously repelling and absorbing moisture. In still other embodiments, the first and second plasma coatings  130  and  132  may be the same. For example, a hydrophobic coating and/or a hydrophilic coating may be on both sides of the filter  11 . Table 1 below illustrates other possible combinations of plasma coatings, but is not intended to be limiting. 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 First Plasma Coating 130 
                 Second Plasma Coating 132 
               
               
                   
                   
               
             
             
               
                   
                 Wear resistance 
                 Hydrophobic 
               
               
                   
                 Wear resistance 
                 Hydrophilic 
               
               
                   
                 Hydrophilic 
                 Hydrophobic 
               
               
                   
                 Chemical/Corrosion Resistance 
                 Hydrophobic 
               
               
                   
                 Chemical/Corrosion Resistance 
                 Hydrophilic 
               
               
                   
                   
               
             
          
         
       
     
         [0025]      FIG. 6  is a cross-sectional side view of an embodiment of a plasma treated turbine air filter  11  without a frame. The filter  11  defines a first side  142  (upstream or intake side), a second side  144  (downstream or exhaust side), a first end  146 , and a second end  148 . As illustrated, the filter  11  defines a zigzag shape with protrusions  150  and recesses  152  between the first end  146  and the second end  148 . In certain embodiments, the filter  11  may include an internal frame and/or filter media. For example, the frame may extend about the parameter (e.g., ends  146  and  148 ) of the filter  11  enclosing a zigzag shaped filter media. Although  FIG. 6  illustrates the filter  11  as a zigzag shape, it may define a variety of different shapes (e.g., parabolic, concave, flat, corrugated ribbed, sinusoidal, etc.). As illustrated, the first and second sides  142 ,  144  include a respective first plasma coating  154  and a second plasma coating  156 . The coatings  154  and  156  may be the same coating or different coatings. For example, the coatings  154  and  156  may represent a single common plasma coating. By further example, coating  154  may be hydrophilic, while coating  156  is hydrophobic and vice versa. As explained above, the combination of hydrophobic and hydrophilic coatings may more effectively protect a gas turbine  12  from moisture, rather than filter  11  covered by only a hydrophobic or hydrophilic coating. 
         [0026]    Furthermore, the first and second plasma coatings  154  and  156  may add strength, corrosion/chemical resistance, and abrasion resistance to the filter  11 . For example, first and second plasma coatings  154  and  156  may increase the strength of the filter  11 . Thus, filter  11  with first and second coatings  154  and  156  may better resist stress caused by high winds, such as wind storms. Furthermore, the first and second plasma coatings  154  and  156  may provide abrasion protection of the filter  11 . For example, a filter  11  operating in a desert environment may experience abrasive conditions caused by sand in the air. Therefore, the first and/or second plasma coatings  154  and  156  may provide an abrasive resistant outer-shell that limits wear and extends the life of filter  11 . The first and second coatings  154  and  156  also may provide protection against mold and mildew. For example, a hydrophobic coating may repel water, thereby reducing the possibility of moisture, mold, and mildew penetration in the filter  11 . In addition, the first and second plasma coatings  154  and  156  may provide protection in a corrosive environment, e.g., a salty environment. 
         [0027]      FIG. 7  is a side view of an embodiment of a plasma treated turbine air filter  11 . The filter  11  defines a front face  172  (upstream or intake side), a rear face  174  (downstream or exhaust side), a first frame portion  176 , and a second frame portion  178 . The front face  172  is covered with a first plasma coating  180  and second plasma coating  182 , which may be the same or different from one another. The rear face  174  is covered with a third plasma coating  184  and fourth plasma coating  186 . Although,  FIG. 7  illustrates four coatings, the filter  11  may be covered with any number and arrangement of plasma coatings. For example, the filter  11  may be covered with 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more plasma coatings, which may be the same or differ from one another. 
         [0028]    Specifically, the first plasma coating  180  and second plasma coating  182  may be hydrophobic coatings, while the third plasma coating  184  and fourth plasma coating  186  are hydrophilic coatings. As explained above, hydrophobic coatings on the front face  172  of the filter  11  block or repel moisture from entering the filter  11 , while hydrophilic coatings on the rear face  174  absorb moisture that passes through the hydrophobic coatings. In this manner, the plasma coatings combine to protect the gas turbine  12  from moisture. 
         [0029]    In still other embodiments, the first plasma coating  180  and third plasma coating  184  may enhance filtration (e.g., moisture or particulate), while the second coating  182  and fourth coating  186  increase filter strength, increase chemical/corrosion resistance, improve abrasion resistance, or any combination thereof, or vice versa. For example, the third and fourth plasma coatings  182 ,  186  may be hydrophobic coatings that protect the filter  11  in a moisture rich environment (e.g., fog). In still other embodiments, the first and third plasma coatings  180  and  184  may be coatings that increase the strength of the filter  11 , while the second and fourth plasma coatings  182 ,  186  enhance filtration (e.g., moisture or particulate). In another embodiment, the first and third plasma coatings  180 ,  184  may enhance filtration, while the second and fourth plasma coatings  182 ,  186  protect the first and third coatings  180 ,  184  in an abrasive environment (e.g., a desert environment). Table 2 below illustrates other possible combinations of plasma coatings, but is not intended to be limiting. 
         [0000]    
       
         
               
               
               
               
             
           
               
                 TABLE 2 
               
               
                   
               
               
                 First Plasma 
                 Second Plasma 
                 Third Plasma 
                 Fourth Plasma 
               
               
                 Coating 180 
                 Coating 182 
                 Coating 184 
                 Coating 186 
               
               
                   
               
             
             
               
                 Wear resistance 
                 Hydrophobic 
                 Chemical/ 
                 Hydrophilic 
               
               
                   
                   
                 Corrosion 
               
               
                   
                   
                 Resistance 
               
               
                 Wear resistance 
                 Hydrophilic 
                 Chemical/ 
                 Hydrophilic 
               
               
                   
                   
                 Corrosion 
               
               
                   
                   
                 Resistance 
               
               
                 Hydrophobic 
                 Hydrophobic 
                 Hydrophilic 
                 Hydrophilic 
               
               
                 Chemical/ 
                 Hydrophobic 
                 Hydrophilic 
                 Hydrophilic 
               
               
                 Corrosion 
               
               
                 Resistance 
               
               
                 Wear resistance 
                 Hydrophilic 
                 Hydrophilic 
                 Chemical/ 
               
               
                   
                   
                   
                 Corrosion 
               
               
                   
                   
                   
                 Resistance 
               
               
                   
               
             
          
         
       
     
         [0030]    Technical effects of the invention include the ability to enhance filter properties post fabrication using plasma deposition techniques. The filter may include one or more plasma coatings that enhance its ability to filter air or improve another property. As explained above, the filter may include 2 or more different coatings on the same or different regions of the filter, such as upstream and downstream sides of the filter. For example, the filter may have a hydrophobic coating on one side of the filter and a hydrophilic coating on the opposite side of the filter. The combination of these different plasma coatings may advantageously assist in repelling and draining moisture from a filter. In addition, the different plasma coatings may improve strength, wear resistance, abrasion resistance, corrosion resistance, chemical resistance, biological resistance, or any combination thereof. 
         [0031]    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.