Patent Document

BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention is related to an engine air particle separator and filter assembly. More particularly, the present invention relates to an improved engine air particle filter assembly that can either function as an Engine Air Particle Separator (EAPS) or as a warm weather barrier filter kit for aircraft operations in extreme sand and dust environments. 
         [0003]    2. Description of Related Art 
         [0004]    Helicopters often operate utilizing various types of combustion engines. Inherent in the operation of these engines is that air continuously flows through an intake on the outer periphery of the helicopter and into the engine. The air will then mix with the fuel resulting in a mixture of fuel to air that has optimum ratios. The fuel/air mixture is then subjected to a spark and the mixture is ignited. The resulting explosion provides the force that is necessary to drive the various engine components. 
         [0005]    Helicopters operate in a variety of environmental conditions. The various conditions result in air that contains impurities of various sizes and composition. For example, the air in an urban environment may contain impurities of relatively larger sizes, such as leaves, while the air in a desert may contain impurities of relatively smaller sizes, such as grains of sand. In addition, helicopters operate in a variety of temperatures depending on the time of year and geographical location. In very cold temperatures, freezing of the engine components may occur unless preventative action is taken. 
         [0006]    Currently, engine air particle separators (EAPS) and barrier filter systems are used to filter the air prior to entering the helicopter&#39;s internal combustion engine. The environmental conditions in which the helicopter often determines whether EAPS or barrier filters will be used. For example, EAPS may be more suitable to use when the air contains impurities of relatively larger sizes or in freezing temperatures. On the other hand, barrier filter technology may prove to be more suitable in desert-like environments where the air contains impurities of relatively smaller sizes, e.g., grains of sand. 
         [0007]    As shown in  FIG. 2 , currently available EAPS include a plurality of individual centrifugal separator swirl tubes which are located in two panels. In use, engine air particle separators (EAPS) are sized and configured to be mounted ahead of the engine inlet ducts and are designed to reduce the erosion of the aircraft engines due to sand and dust ingestion. Moreover, EAPS are configured to discharge dirty air overboard through a scavenge system powered by an electric blower while allowing cleaned air to enter the engine inlet. 
         [0008]    Additionally, EAPS require virtually no cleaning since there is not a buildup of filtered impurities in the unit. Thus, the engine power penalty remains substantially constant with time. In addition, EAPS have been shown to operate successfully in some icing conditions. Thus, not only do the EAPS act as a particle separator, but it also provides a level of ice protection for the engine as well. The level of ice protection depends upon the orientation of the swirl tubes to the free stream airflow. Prior to the development of EAPS, the inlet ducts, as shown in  FIG. 3 , were equipped with integral electric heating elements to prevent the formation of ice on the engine. In using EAPS, the integral electric heating elements can either be disabled or removed. 
         [0009]    However, recent field experience has shown that EAPS provide inadequate particle separation efficiency in severe sand and dust operational environments. This is mainly due to the low efficiency of the swirl tubes to remove very fine particles from the inlet air stream. As a result, there is an unacceptable level of engine erosion protection. 
         [0010]    In environments such as these, vehicles are often equipped with barrier filters. Barrier filter technology, in contrast with EAPS technology, has been shown to provide satisfactory engine erosion protection in sandy and dusty environments. Barrier filters are capable of separating approximately 99% of very fine particles. The particles that are filtered from the air are retained in the filter. As the sand and dust accumulates in the filter, power of the engine is compromised resulting in decreased performance of the aircraft. Consequently, the filters require servicing at regular intervals in order to remove the dirt and dust. The time and expenses associated with the maintenance can be costly to the owner of the aircraft. It is, therefore, of great interest to the owners to reduce the frequency of engine maintenance. 
         [0011]    Currently there is no quick and inexpensive way to switch from the use of an EAPS with vortex tube technology and to an assembly using barrier filter panels. If one wishes to make such a change, the filter system as a whole must be removed from the helicopter and replaced with another filter system. The capability to quickly and inexpensively change switch from using the vortex tubes to the barrier filter panels would be beneficial to the owner of the aircraft. Accordingly, there is a need for a way to quickly and effectively change from one filter media to another. 
       BRIEF SUMMARY OF THE INVENTION 
       [0012]    It is an object of the present invention to provide an improved engine air particle filter assembly that can either function as an Engine Air Particle Separator (EAPS) or as a warm weather barrier filter kit for aircraft operations in extreme sand and dust environments. 
         [0013]    These and other objects and advantages of the present invention are provided by an engine air particle filter system in a helicopter having a support structure that is fixed to the helicopter. The support structure has a plurality of ribs. The plurality of ribs and the support structure form a plurality of openings. A plurality of trays, containing a filter media, each fit into each one of the plurality of openings in an airtight configuration. A connector releasably secures each one of the plurality of trays to the support structure so that each one of the plurality of trays can be selectively inserted and withdrawn from each one of the plurality of openings. 
         [0014]    A method of converting from a first air filtering media to a second air filtering media in an engine air particle filter assembly is also provided. The method includes removing a plurality of connectors that releasably secure a first plurality of trays to a support structure of the engine air particle filter assembly, wherein each one of the first plurality of trays contains the first air filtering media, removing the first plurality of trays from the support structure, inserting a second plurality of trays into the support structure, wherein each one of the second plurality of trays contains the second air filtering media, and reconnecting the plurality of connectors so that the plurality of connectors releasably secure the second plurality of trays to the support structure. 
         [0015]    The above-described and other features and advantages of the present invention will be appreciated and understood by those skilled in the art from the following detailed description, drawings, and appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0016]      FIG. 1  is a top perspective view of a helicopter having an exemplary embodiment of an engine air particle separator (EAPS) according to the present disclosure in use on a helicopter. 
           [0017]      FIG. 2  is an example of a currently available EAPS. 
           [0018]      FIG. 3  is an exploded view of the EAPS of  FIG. 2 . 
           [0019]      FIG. 4  is a top side perspective view of a first embodiment of an engine air particle filter system shown in  FIG. 1 . 
           [0020]      FIG. 5  is a partially exploded top perspective view of the engine air particle filter system shown in  FIG. 4 . 
           [0021]      FIG. 6  is a side perspective view of a second embodiment of an engine air particle filter system shown in  FIG. 1 , utilizing vortex tubes; 
           [0022]      FIG. 7  is a side perspective view of a second embodiment of an engine air particle filter system shown in  FIG. 1 , utilizing barrier filters; 
           [0023]      FIG. 8  is a partially exploded top perspective view of the engine air particle filter system shown in  FIGS. 6 and 7 . 
           [0024]      FIG. 9  is a partially assembled view of the engine air particle filter system shown in  FIG. 8 . 
           [0025]      FIG. 10  is a partially exploded side perspective view of the engine air particle filter system shown in  FIGS. 6 and 7 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    Referring to the drawings and in particular to  FIG. 1 , an exemplary embodiment of an engine air particle filter system  10  in relation to an internal combustion engine  14  on a helicopter  12  is shown. Although engine air particle filter system  10  is shown in accordance with helicopter  12 , it should be recognized that engine air particle filter system  10  can be used in combination with an internal combustion engine in any type of vehicle, for example, an airplane or an automobile. 
         [0027]    Advantageously, system  10  allows for rapidly switching between various types of filter media in order to effectively filter air in a variety of environmental conditions. 
         [0028]    As illustrated in  FIGS. 4 and 5 , engine air particle filter system  10  includes a support structure  18 . Support structure  18  includes a plurality of ribs  28 . Two adjacent ribs and two parts of support structure  18  define an opening  40 . Although  FIG. 4  shows engine air particle filter system  10  having six ribs and five openings  40 , it is foreseen that engine air particle filter system  10  according to the present disclosure can have any number of ribs and openings deemed suitable. Furthermore, as seen in  FIG. 4 , support structure  18  forms an approximately semicircular shape. It is foreseen, however, that support structure  18  can have any suitable shape, including, but not limited to a roughly circular shape as shown in  FIGS. 6 and 7 . In a preferred embodiment, support structure  18  and each of the plurality of ribs  28  are made of a material sufficient to withstand the stress and heat associated with helicopter  12 . For example, it is contemplated by the present disclosure that support structure  18  and each one of the plurality of ribs  28  may be made of steel, aluminum, a composite, and any combinations thereof. 
         [0029]    As illustrated in  FIGS. 4 through 7 , engine air particle filter system  10  also has a front end  30 . Front end  30  may be configured in any shape that is desired in that it forms an airtight connection with support structure  18 . In a preferred embodiment, front end  30  is made of a material sufficient to withstand the stress and heat associated with helicopter  12 . For example, it is contemplated by the present disclosure that front end  30  may be made of steel, aluminum, a composite, and any combinations thereof. 
         [0030]    Engine air particle filter system  10  also contains a plurality of trays  20  corresponding in number to the number of openings  40 . It is foreseen that tray  20  contains a filter media. The filter media can be of any type suitable for effectively filtering and removing impurities from the air. In a preferred embodiment, the filter media may be barrier filter panels  34  ( FIG. 7 ) or vortex tubes  32  ( FIG. 6 ). 
         [0031]    As illustrated in  FIGS. 6 and 7 , tray  20  has a roughly rectangular shape although it is contemplated that tray  20  can have any shape suitable for fitting into opening  40 . In addition, tray  20  has a roughly flat top surface  48 . However, it is foreseen that top surface  48  may be curved. Tray  20  has a left lateral side trim  42  that is elevated in relation to top surface  48  of tray  20  and a right lateral side trim  44  that is flat with respect to top surface  48  of tray  20 . Tray  20  also has a front trim  56  and back trim  58 . In a preferred embodiment, the right and left lateral side trims  42  and  44  and front and back trims  56  and  58  are made of any material deemed suitable to withstand the stress and heat associated with helicopter  12  while forming integral edge seal  46 . Integral edge seal  46  is an airtight connection between the right and left lateral side trims  42  and  44 , rib  28 , and support structure  18 . For example, it is contemplated by the present disclosure that right and left lateral side trims may be made of steel, aluminum, composite plastic, plastic compositions, rubber, rubber compositions, and any combination thereof. In addition, in a preferred embodiment each of trays  20  have the same size and shape. 
         [0032]    Furthermore, engine air particle filter system  10  includes one or more connectors  52 . As illustrated in  FIG. 8 , connector  52  may be of any type that allows tray  20  to be releasably secured to support structure  18  while also forming an airtight connection between tray  20  and support structure  18 . In a preferred embodiment, connector  52  comprises a plurality of quick-turn fasteners along the longitudinal center axis of left lateral side trim  42 . Right lateral side trim  44  of adjacent tray  20  has a plurality of holes that correspond to the plurality of quarter-turn fasteners on left lateral side trim  42  in adjacent tray  20 . In addition, support structure  18  has a plurality of quick-turn retainers corresponding in location to both the quarter-turn fasteners on left lateral side trim  42  and the plurality of holes on right lateral side trim  44 . It is foreseen that other connectors may include, but not be limited to, any other type of suitable hardware. 
         [0033]    Trays  20  nest within support structure  18 . Both left and right lateral side trims  42 ,  44  of an individual tray  20  are supported by longitudinal ribs  28 . Front trim  56  of tray  20  rests on front end  30  and rear trim  58  rests on mid-frame support  70  within support structure  18 . All underside surfaces of left lateral side trim  42  and right lateral side trim  44  of tray  20  are coated with sealing material such as bonded-on strips of rubber material. Integral quarter-turn fasteners clamp tray edges along each lateral side trim to support structure  18 . Additionally, the bottom of tray  20  has insert indexes on support structure  18  that provide consistent alignment and internal sealing. 
         [0034]    In one embodiment, as seen in  FIGS. 5 ,  8 , and  9 , during assembly of engine air particle filter system  10 , each of a plurality of trays  20  are identically constructed wherein each tray  20  has a left lateral side trim  42  having a plurality of quarter-turn fasteners aligned along a longitudinal center axis of the left lateral side trim. Each tray  20  also has right lateral side trim  44  that has a series of holes corresponding in location and alignment to the series of quarter-turn fasteners on left lateral side trim  42 . In addition, support structure  18  has a plurality of quarter-turn retainers corresponding to the series of holes in right lateral side trim  44  and the series of quarter-turn fasteners on left lateral side trim  42 . A first tray  20  is placed into a corresponding opening  40 . Left lateral side trim  44  of first tray  20  rests on and is secured to a raised edge surface on support structure  18  by any means sufficient to form a connection between the left lateral side trim and the raised edge surface of the support structure. A second tray is then positioned so that the series of quarter-turn fasteners on left lateral side trim  44  of the second tray is inserted through the series of holes in right lateral side trim  44  of the first tray and into the corresponding quarter-turn retainer on support structure  18 . A quarter-turn in a clockwise direction of the quarter-turn fastener will secure each of the first and second trays  20  to support structure  18  in an airtight fashion forming integral edge seal  46  between the first and second trays. Each additional adjacent tray will then be added sequentially in a similar fashion until each of openings  40  are filled with trays  20 . When last tray  20  is added, right lateral side trim  44  will be secured to support structure  18  by any means sufficient to secure right lateral side trim  44  to support structure  18  in an air-tight fashion. For example, a strip of metal with a series of quarter-turn fasteners corresponding to the series of holes in right lateral side trim  44  of the last tray could be used to secure last tray  20  to support structure  18  in an airtight connection. 
         [0035]    Integral edge seals  46  form airtight connections between each of trays  20  preventing air from escaping through any spaces in engine air particle filter system  10 . Additionally, when tray  20  is secured to support structure  18 , an airtight connection is formed between front trim  56  and support structure  18 . Similarly, an airtight connection is also formed between back trim  58  and support structure  18 . 
         [0036]    In a second embodiment, and as illustrated in  FIG. 10 , each of identical trays  20  slide into each of the plurality of openings  40  in a sequential manner until each one of openings  40  has been filled with a corresponding tray  20 . Each of the trays  20  will then be secured to support structure  18  as discussed above. The right lateral side trim  44  of the last tray added will be secured to support structure by any means suitable to form an airtight connection between right lateral side trim  44  and support structure. For example, a strip of metal having a plurality of quarter-turn fasteners that correspond and location to each of the holes of right lateral side trim  44  may be used as discussed above. In other embodiments, it is foreseen that screws or bolts may be used for a more permanent attachment of last tray  20  to support structure  18 . 
         [0037]    Once system  10  is assembled, support structure  18  is attached to helicopter  12  in any manner deemed appropriate. For example, in one method, the forward most portion of the EAPS barrel is attached to the aircraft via an aircraft mounted tubular support structure known as the “J-bar”. The EAPS barrel hinges on this tube and acts much like a door. At the rear, an airframe mounted ring provides a fixed landing for the EAPS barrel mounted retaining latches to attach. 
         [0038]    Operation of engine air particle filter system  10  according to the present invention will now be described with reference to  FIGS. 1 ,  6  and  7 . 
         [0039]    As shown in  FIG. 1 , engine air particle filter system  10  is positioned in front of internal combustion engine  14 . There are airtight connections between each part of engine air particle filter system  10  so that air laden with impurities flows through the filter media of each one of trays  20 . The amount of air that flows through the filter media depends on the size and shape of each tray  20  and its orientation in relation to the air path. 
         [0040]    In a first embodiment, when tray  20  contains barrier filter panels  34 , the impurities from the air collect on the surface of the filter panels and the filtered air flows through the filter media and into engine air particle filter system  10 . The air then flows through a tube and into an inlet in internal combustion engine  12 . During servicing, each tray  20  can be quickly detached from support system  18  by disconnecting connector  52  and removing tray  20 . The barrier filter panels  34  can then be cleaned wherein the impurities that have collected on panels  34  can be removed. As an alternative, a replacement tray  20  containing filter media can be inserted into opening  40  and quickly secured into place as discussed previously. 
         [0041]    In another embodiment, tray  20  will contain vortex tubes  32  as the filter media. During use, air that is laden with impurities will flow through the vortex tubes wherein the impurities will be removed from the air. Clean air will then enter the engine through an inlet. The dirty air, on the other hand, is discharged overboard through a scavenge system powered by an electric blower (not shown). During servicing, each tray  20  can be quickly removed from support system  18  whereupon the trays and filter media can be cleaned or alternatively a replacement tray  20  can be reinserted into opening  40  and secured to support system  18  as discussed previously. 
         [0042]    In a preferred embodiment, each one of the plurality of trays  20  will have the same type of filter media. However, it is foreseen that in some embodiments, trays  20  containing differing filter medias may be used. Additionally, it is also contemplated that during servicing of engine air particle filter system  10 , tray  20  containing one type of filter media, e.g. vortex tubes  32 , will be replaced by another tray  20  containing a different type of filter media, e.g. barrier filter panels  34 , or vice versa. 
         [0043]    It should also be noted that the terms “first”, “second”, “third”, “upper”, “lower”, and the like may be used herein to modify various elements. These modifiers do not imply a spatial, sequential, or hierarchical order to the modified elements unless specifically stated. 
         [0044]    While the present disclosure has been described with reference to one or more exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment(s) disclosed as the best mode contemplated, but that the disclosure will include all embodiments falling within the scope of the appended claims.

Technology Category: b