referring first to fig1 there is shown a stylized depiction of hvac equipment 10 within an enclosure 12 . the hvac equipment 10 may be utilized to heat the interior of a building ( not shown ), in which event the equipment 10 includes a burner ( 13 ) and a fan or blower 14 . when the blower 14 operates it draws air into the enclosure 12 through an intake 16 , as shown by the arrow 18 , following which the air is heated by the burner and is forced by the blower 14 through a duct 20 into the interior of the building , as shown by the arrow 22 . the duct 20 may pass into the building through an opening 24 formed through the roof 26 thereof . other arrangements , such as those utilizing a burner and heat exchanger to heat the air are clearly contemplated . typically mounted in the intake 16 is a grill or louver , generally denoted 30 . the function of the louver 30 is to prevent personnel , birds and small animals from intruding into the interior of the enclosure 12 . the louver may also , as with the present invention , obviate the entry of moisture and other massive , dense particulate material which is entrained in the air from entering the enclosure to the detriment of the hvac equipment . prior art louvers 30 suffer from the shortcomings discussed earlier . referring now to fig2 a louver assembly 30 according to the present invention comprises a first plurality 32 of spaced apart vanes 34 and a second plurality 36 of spaced apart vanes 38 . the vanes 34 and 38 are preferably generally vertically oriented in fig1 and 3 , and extend generally from near the top to near the bottom of the intake 16 . as discussed in more detail below , the vanes 34 and 38 are preferably fabricated from formed sheet metal . the vanes 34 and 38 are rigidly and stationarily held in the intake 16 in a frame 40 which mounts the tops and bottoms of the vanes 34 and 38 between a top member 41t and a bottom member 41b of the frame 40 in any conventional manner . the frame 40 is , as shown in fig3 held in the intake 16 by attachment to a sidewall 42 of the enclosure 12 in any conventional fashion . as seen in fig2 the vanes 34 and 38 are formed by simple bending with no projections or protrusions such as might be effected by attaching additional material , by extrusion or by complex retroflex bending . preferably the bending produces acute angle bends of about 70 ° to 80 °, although other angles are contemplated , as should be obvious . each vane 34 and 38 has a plurality of first segments 50 . the segments 50 are planar ; the segments 50 of each vane 34 and 38 are parallel to each other . each vane 34 and 38 also includes a plurality of second segments 52 . the segments 52 are normal to the segments 50 and serve to interconnect serial segments 50 within each vane 34 and 38 . the segments 52 are mutually parallel within each vane 34 and 38 . as clearly shown , in cross - section or end - on , the vanes 34 and 38 have a simple stair - step - like configuration . the frame 40 mounts the vanes 34 and 38 so that they extend generally toward or into the interior of the enclosure 12 , that is , in the direction of air flow 18 and away from the point of entry of the air into the intake 16 . further , as shown , the frame 40 holds the first and second pluralities 32 and 36 so that they have a mirror image spatial relationship relative to an axis of symmetry 60 of the assembly 30 . free edges 62 of the segments 50 of the vanes 34 and 38 closest to the axis 60 are preferably closely spaced with the space therebetween being closed by a cap 63 located behind the segments 50 . if desired the free edges 62 may be made continuous by simple engagement , by joining the edges 62 in any known manner , such as by welding or brazing , or by fabricating the two vanes 34 and 38 integrally from a single piece of sheet metal . passageways or spacings 64 between adjacent vanes 34 and 38 permit air to pass therethrough . these passageways are directed somewhat angularly away from both the axis 60 and the location of entry of air into the assembly 30 . the frame 40 includes generally upstanding side walls 66 which cooperate with the first adjacent vane 34 and 38 to define left - most and right - most points of entry for air . preferably , as shown in fig1 the assembly 30 is tilted so that the bottom thereof is moved toward the interior of the enclosure 12 relative to the top of the enclosure 12 . conveniently this may be achieved by angling the side wall 42 . this orientation of the assembly 30 provides some shielding of the intake 16 from falling rain and other precipitation . the vanes 34 and 38 may have three segments 50 interconnected by two segments 52 , although this number may be adjusted to suit the particular environment in which the assembly 30 is used in a manner which ensures that the assembly functions efficiently as a moisture separator . moreover , as shown , the lengths of the segments 50 and 52 may vary , with the central segment 52 being elongated to accommodate attachment thereto of facilities , such as thin rods or spokes , which mount the vanes 34 and 38 to the members 41t and 41b . it has been found that the assembly 30 functions well as a moisture separator if the distance 80 between the free edge 82 of a forward segment 50 and the surface 84 of the adjacent segment 52 is between 1 to 11 / 2 inch . the same distance 80 obtains between the surfaces 84 of adjacent but offset segments 52 . similarly , it is preferred if the distance 86 between the surfaces 84 of adjacent and overlying segments 52 is between 2 to 3 inches . in operation , the blower 14 draws air through the intake 16 and into the enclosure 12 . in so moving , the air flows through the louver assembly 30 via the passageways 64 defined between the vanes 34 and 38 . the stair - step configuration of the passageways 64 defined by the vanes 34 and 38 causes the entering air to follow a plurality of tortuous paths which , as previously explained , results in moisture and other entrained particulates being centrifugally removed and impinging on the surfaces of the vanes 34 and 38 . the impinging material runs down the vanes where it is collected or directed to a drain or the like by drain facilities ( not shown ) of any known construction . as shown by the arrows 90 , the air following the outermost passageways 64 impinges on the side walls 66 of the frame 40 . this impingement is effective to separate moisture and other entrained particulates from the air , in addition to that separated by the action of the outermost vanes 34 and 38 . moreover , and to the same end , air passing through the inner passageways 64 is also directed at the walls 66 by the angular orientation of the passageways 64 as shown in fig2 . as shown in fig3 from head - on the assembly 30 has a neat , uncluttered appearance . no sight lines into the interior of the enclosure 12 are available . it has been found that as the angle between the segments 50 and 52 approaches 90 °, increasing amounts of separated material become re - entrained in the air stream . contrariwise , with the angle at between about 70 °- 80 °, and particularly at about 75 °, separated material runs down the bend between the segments 50 and 52 rather then re - entering the air stream . although certain specific embodiments of the present invention are described in the foregoing detailed description , it should be understood that this invention is not limited to such specific embodiments , and is capable of modification and rearrangement .