Abstract:
Aspirators for inflating devices such as (but not limited to) aircraft evacuation slides and rafts are detailed. Housings of the aspirators may be made of wound filaments of composite materials, reducing their weight as compared to conventional metal structures. Such actions as reconfiguring and repositioning jet nozzles within the housings also contribute to enhancing performance of the aspirators.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates to devices used to inflate objects and more particularly, although not necessarily exclusively, to aspirators employed to control flow of inflation gas to evacuation slides and rafts. 
       BACKGROUND OF THE INVENTION 
       [0002]    U.S. Pat. No. 4,368,009 to Heimovics, et al., whose contents are incorporated herein in their entirety by this reference, illustrates an aspirator intended to inflate structures including aircraft evacuation slides and rafts. The aspirator includes a housing made of fiber-reinforced plastic material and a pair of metal flapper valve plates. High-pressure gas enters the top of the housing in a single location along the (central) longitudinal axis of the housing, essentially perpendicular to a plane containing the flapper valve plates. The gas thereafter is exhausted by jets within the housing so as to create a localized region of low pressure therein, existence of which causes the flapper valve plates to open. Opening of the plates, in turn, allows ambient air to enter the housing for inflating a slide or raft. 
         [0003]    An existing aspirator of the assignee of this application (referred to herein as the “Existing Air Cruisers Aspirator”) comprises a housing made principally of metal, a pair of metal flapper valve plates, and two sets of jet nozzles spaced longitudinally within the housing. High-pressure gas enters the housing in two locations spaced longitudinally along a housing wall, essentially parallel to a plane containing the flapper valve plates. An inner concentric ring of nozzles positioned closer to the valve plates communicates with an upper gas entry location, while an outer concentric ring of nozzles positions farther from the valve plates communicates with the lower gas entry location. 
         [0004]    Although the Heimovics patent details an aspirator in which high-pressure gas enters the top of the housing, most commercially successful aspirators, including the Existing Air Cruisers Aspirator, are side-entry devices. This configuration allows the entry apertures to be positioned longitudinally adjacent the nozzles, minimizing the distance the high-pressure gas must travel within the housing before exiting via the nozzles. Reducing the travel distance obviously decreases the time required for aspiration to begin; it reduces loss of gas and gas pressure as well. 
         [0005]    Forming entry apertures in the metallic side wall of the Existing Air Cruisers Aspirator does not materially compromise the strength or integrity of the wall. Doing so in non-metallic devices may be problematic, however. Nevertheless, need for principally non-metallic aspirators is increasing as airframe manufacturers, in particular, seek to design aircraft of decreased weight. Hence valuable to these manufacturers are efficient, reliable aspirators of reduced weight. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention provides such valuable aspirators. Presently-preferred versions of the aspirators incorporate housings primarily of wound filaments of composite materials. Utilizing such materials may reduce overall weight of the devices by approximately one-half to two-thirds. 
         [0007]    Filaments of aramids (e.g. Kevlar), fiberglass, or any other suitable material may be employed. Carbon fibers present an especially preferred material for the composite portions of the housings. Such material is, however, susceptible to degradation if subjected to high point loading. Consequently, drilling gas-entry apertures through the walls of the housings is, potentially, disadvantageous. 
         [0008]    Accordingly, the present invention contemplates, among other things, positioning gas-entry apertures in a (preferably, although not necessarily) metallic component, such as a cap, at the top of the housing. Unlike the design of the Heimovics patent, however, that of the present invention includes an entry plenum incorporating multiple such apertures communicating with a fluid distribution system preferably (although not necessarily) comprising multiple rings of jet nozzles. Moreover, whereas the jets of the aspirator of the Heimovics patent are located a substantial distance from its flapper valve plates, those of the current invention are not. Instead, by reconfiguring the nozzles as applicants have done, the flapper valve plates may be made to nest within at least one nozzle ring when the plates are open. In essence, then, distance between the plates and at least some nozzles may be reduced to less than the width of the plates. 
         [0009]    Although sometimes referred to as “rings,” sets of these nozzles need not necessarily form structures having circular cross-section. Indeed, presently-preferred rings are shaped as ovals. Reshaping the rings as ovals improves performance of the aspirators, allowing more rapid inflation of evacuation products. 
         [0010]    Housings of the present aspirators may include an integral, outwardly extending flange intended to engage a complementary portion of the to-be-inflated object. This flange allows for robust connection between the aspirator and the inflatable, reducing the possibility of their separating prematurely in use. Preferably the flange has circular cross-section, although those skilled in the art will recognize that other shapes may be used to mate with corresponding portions of the inflatable. 
         [0011]    Present housings of the invention additionally may change diameter along their lengths. Whereas the aspirator of the Heimovics patent, for example, appears simply to converge from a larger inlet to a smaller outlet, aspirators of the present invention may size inlets and outlets such that the minimum diameter of the housing is between them. Stated differently, preferred housings of the invention initially converge from the inlets to a central region and then diverge from that central region to the outlets. 
         [0012]    Top cap assemblies of the housing include the gas-entry apertures. These caps may be bonded to bodies of the housings, and effecting the bonding at elevated temperature (e.g. 160° F.) may help ensure subsequent thermal expansion of the device does not compromise the bond. The top cap assemblies further may include internal o-rings to block adhesive from interfering with operation of the flapper valve plates. The o-rings, together with the adhesive, also may function to inhibit galvanic corrosion in use. Of course, those skilled in the relevant field will recognize that other connecting, attaching, or bonding methods may be used instead, even if not preferred. Positioning the entry plenums of the top cap assemblies above the flapper valve plates spaces the plates from any surrounding structure (e.g. the aircraft fuselage), helping ensure airflow into the inlet may always occur. 
         [0013]    It thus is an optional, non-exclusive object of the present invention to provide reduced-weight aspirators without sacrificing performance or reliability. 
         [0014]    It is another optional, non-exclusive object of the present invention to provide aspirators having housings made primarily of wound filaments of composite materials. 
         [0015]    It is also an optional, non-exclusive object of the present invention to provide aspirators whose gas-entry apertures do not extend through walls of the housings. 
         [0016]    It is, moreover, an optional, non-exclusive object of the present invention to provide aspirators having entry-aperture plenums communicating with a fluid distribution system preferably comprising multiple rings of jet nozzles. 
         [0017]    It is a further optional, non-exclusive object of the present invention to provide aspirators with reduced distance between flapper valve plates and the jet nozzles. 
         [0018]    It is yet another optional, non-exclusive object of the present invention to provide aspirators including oval- or other-shaped “rings” of nozzles. 
         [0019]    It is additionally an optional, non-exclusive object of the present invention to provide aspirators including an outwardly extending (annular) flange facilitating connection with an inflatable object. 
         [0020]    It is, furthermore, an optional, non-exclusive object of the present invention to provide aspirators whose housings have minimum diameter at locations intermediate the inlets and the outlets. 
         [0021]    It is an additional optional, non-exclusive object of the present invention to provide aspirators having top caps bonded to housing bodies at elevated temperatures to pre-accommodate thermal expansion, with the caps also designed to inhibit galvanic corrosion of components while the aspirators are deployed. 
         [0022]    Other objects, features, and advantages of the present invention will be apparent to those skilled in the appropriate art with reference to the remaining text and the drawings of this application. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  is an isometric view of a housing body of an exemplary aspirator of the present invention. 
           [0024]      FIG. 2  is an isometric view of, principally, the external side of a top cap assembly of the housing of an aspirator of the present invention. 
           [0025]      FIG. 3  is an isometric view of, principally, the internal side of the top cap assembly of  FIG. 2  (with flapper valve plates removed). 
           [0026]      FIG. 4  is an elevational, cross-sectional view of a portion of part of the top cap assembly of  FIG. 2 . 
           [0027]      FIG. 5  is an isometric view of a jet nozzle assembly of the aspirator of the present invention. 
           [0028]      FIG. 6  is an elevational view of the jet nozzle assembly of  FIG. 5 . 
           [0029]      FIG. 7  is a bottom plan view of the inner ring of the jet nozzle assembly of  FIG. 5 . 
           [0030]      FIG. 8  is a bottom plan view of the outer ring of the jet nozzle assembly of  FIG. 5 . 
           [0031]      FIG. 9  is an isometric view of an exemplary aspirator of the present invention incorporating the body of  FIG. 1 , the top cap assembly of  FIGS. 2-4 , and the jet nozzle assembly of  FIGS. 5-8 . 
           [0032]      FIG. 10  is an elevational, cross-sectional view of the aspirator of  FIG. 9 . 
           [0033]      FIG. 11  is an exploded view of the aspirator of  FIG. 9 . 
           [0034]      FIG. 12  is an exploded view of a spring assembly of the aspirator of  FIG. 9 . 
       
    
    
     DETAILED DESCRIPTION 
       [0035]    Illustrated in  FIG. 9  is exemplary aspirator  10  consistent with the present invention. Aspirator  10  may be formed of housing  14  comprising body  18  and top cap assembly  22 . Body  18  preferably has circular cross-section, albeit with diameter varying along its length L. Body  18  may, however, be shaped other than as depicted in  FIGS. 1 and 9 . 
         [0036]    Contrasted with conventional aspirator housing bodies, body  18  beneficially may be formed as a monolithic structure of wound filaments rather than of one or more machined metal components. Filaments of carbon, aramids (including Kevlar), fiberglass, or otherwise may be wound to create body  18 , providing the body  18  with satisfactory strength while reducing its weight substantially as compared with conventional metallic bodies. 
         [0037]    Protruding externally from body  18  is flange  26 . The flange  26  preferably is annular, although it may assume other shapes instead. Regardless of its shape, however, flange  26  is intended to engage a complementary portion of an inflatable object so as to connect the object to aspirator  10 . Flange  26  advantageously may be formed integral with the remainder of body  18 , although persons appropriately skilled in the art will recognize that it may be formed otherwise if desired. Likewise, body  18  may connect to the inflatable object other than by using flange  26 , so in this respect the flange  26  is optional. 
         [0038]    Body  18  may comprise at last two generally frustoconical sections  30 A-B. Section  30 A has maximum diameter at inlet  34 , tapering to minimum diameter at region  38 . Section  30 B likewise has minimum diameter at region  38 , expanding to its maximum diameter at outlet  42 . The converging/diverging nature of body  18  promotes airflow through aspirator  10  and thus presently is preferred. 
         [0039]    Detailed in  FIGS. 2-4  is top cap assembly  22  of housing  14 . Cap assembly  22  may include at least rim  46 , plenum  50 , fitting  54 , and flapper valve plates  58 A-B. As illustrated especially in  FIG. 9 , plenum  50  beneficially protrudes above rim  46 ; when aspirator  10  is deployed for use, protruding plenum  50  inhibits the aspirator  10  from being installed with rim  46  flush against a surface, thereby helping ensure airflow paths always exist in areas adjacent valve plates  58 A-B. 
         [0040]    Rim  46  may be bonded to body  18  at inlet  34 . In some embodiments of the invention, rim  46  is mounted onto body  18 , with adhesive then injected into the rim  46  via injection holes  62 . Appearance of adhesive in weep holes  66  provides visual evidence of relatively uniform dispersion of the adhesive. 
         [0041]    Fitting  54  includes inlet port  70  and is designed for direct or indirect connection to a source of pressurized fluid. Such fluid enters plenum  50  through port  70 , hence avoiding any need to drill entry apertures through body  18 . The fluid thereafter exits plenum  50  via one or more outlet ports  74 , of which four (as shown in  FIG. 3 ) preferably exist. When more than one outlet port  74  is present, the ports  74  preferably are spaced radially across rim  46 . Any appropriate structure may connect plenum  50  and flapper valve plates  58 A-B to rim  46 ; in some versions of aspirator  10 , such structure may include fasteners  78  placed in holes  82  of plenum  50  and in corresponding holes of a base  79  ( FIG. 11 ) to which valve plates  58 A-B attach using hinges  80 . 
         [0042]    Communicating with outlet ports  74  is nozzle assembly  82  (see  FIGS. 5-8 ). Included as part of assembly  82  are multiple jet nozzles  86  from which pressurized fluid is exhausted. Also part of assembly  82  is distribution system  90 A-B (preferably, although not necessarily, in the form of “rings”) as well as fluid conduits  94 A-D. Although  FIGS. 5-6  depict two distribution rings and four conduits, more or fewer of these components may be utilized instead. 
         [0043]    Assembly  82  also incorporates mounting plate  98 , whose holes  102  align for fastening (using fasteners  78 ;  FIGS. 10-11 ) directly or indirectly to plenum  50 . When mounting plate  98  is so fastened, each of conduits  94 A-D communicates with a corresponding outlet port  74  so as to convey pressurized fluid to distribution system  90 A-B. Outer conduits  94 A and  94 D communicate with outer distribution system  90 A, while inner conduits  94 B-C communicate with inner distribution system  90 B. Assembly  82  may be designed so that no substantial closed paths exist that might otherwise allow unwanted debris (e.g. salt) to accumulate. 
         [0044]    Either or both of the “rings” of distribution system  90 A-B may assume any desired shape. Presently preferred, however, is an oval shape for both ring  90 B and ring  90 A as shown in  FIGS. 7-8 , respectively. This oval shape complements the shape of body  18  in a manner facilitating aspiration. 
         [0045]    The oval shape of, especially, ring  90 A, together with the positioning of ring  90 A above ring  90 B, also permits the rings  90 A-B to be placed closer to flapper valve plates  58 A-B and inlet  34  than are analogous distribution rings in use today. Indeed, ring  90 A is sized, shaped, and positioned so that valve plates  58 A-B, when fully open, may nest within space SP bounded by ring  90 A. Consequently, distance D ( FIG. 10 ) between inlet  34  and ring  90 A may be less than the radius R (or width) of a valve plate  58 A (or  58 B), as the valve plate  58 A (or  58 B) will not contact assembly  82  even when fully open. This closer placement of rings  90 A-B to inlet  34  enhances efficient intake of gas through inlet  34  when nozzles  86  are operating. 
         [0046]    Illustrated in  FIG. 11  are other features of aspirator  10 , including spring assembly  106  as well as o-ring  110  and base  79  defining portions of cap assembly  22 . As noted earlier, fasteners  78  may function to connect nozzle assembly  82  and cap assembly  22  (including base  79 ) so that fluid communication between plenum  50  and nozzle assembly  82  may occur. 
         [0047]    Spring assembly  106 , finally, biases valve plates  58 A-B to the position shown in  FIGS. 9-10  in which plates  58 A-B close inlet  34 . In particular, arms  114  of assembly  106  connect spring  118  to hinges  80 . When operational, nozzles  86  create sufficient force in the direction F of  FIG. 10  so as to overcome the biasing force of spring  118 , causing valve plates  58 A-B to open. In certain versions of aspirator  10 , valve plates  58 A-B are non-metallic, preferably being made of stronger, more rigid carbon or other fiber-reinforced material. 
         [0048]    The foregoing is provided for purposes of illustrating, explaining, and describing embodiments of the present invention. Modifications and adaptations to these embodiments will be apparent to those skilled in the art and may be made without departing from the scope or spirit of the invention. In particular, words of position (such as, but not limited to “top,” “bottom,” etc.) used herein relate to a nominal orientation of aspirator  10 . The aspirator  10  need not be deployed in such nominal orientation, however, so none of the positional words of this application should necessarily be interpreted as being absolute in its meaning.