Abstract:
Vent for a duct terminating proximate a wall with a self-leveling feature. The vent includes a first member connectable to the wall in engagement with the duct, a second member rotatably connected to and at least partially in front of the first member and at least one flap pivotally mounted to the second member. Upon rotation of the second member relative to the first member, a pivot axis of each flap is adjustable, e.g., to provide a horizontal pivot axis. Thus, even though the first member is first mounted to the wall, the second member is rotatable relative thereto and this relative rotation enables the orientation or pivot axis of the flap(s) to be adjustable. Accordingly, the first member can be mounted to the wall without concern as to how the flap(s) will be oriented.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates in general to vents for enabling a one-way flow of air from a duct leading from an interior of a structure to a location outside of the structure and more specifically to exhaust vents for mounting to an exterior wall of a structure to provide a one-way flow of exhaust air from a vent member receiving the exhaust air from a clothes dryer to a location exterior of the structure.  
         [0002]     The present invention also relates to self-leveling exhaust vents which include one or more flaps which are rotatable to provide a horizontal axis after connection of the vent to a structure.  
         [0003]     The present invention also relates to general air flow vents which provide control over both the flow and direction of an air stream therethrough.  
       BACKGROUND OF THE INVENTION  
       [0004]     The exhaust from a clothes dryer is typically routed to the outside atmosphere by means of a flexible conduit and some type of vent. The exit location from the corresponding structure is typically an outside wall of the structure or a window panel with the glass pane removed. The flexible conduit is secured to the exhaust conduit of the clothes dryer and then routed to the exit location and optionally connected to a rigid conduit. At the exit location, a flow opening or passageway is created in the structure wall or window panel and a suitable vent is mounted into, onto or across the exit flow opening.  
         [0005]     In order to substantially prevent the inflow or backflow of outside air, as well as to prevent the entry of moisture which may be due to rain or snow, exhaust vents of this type may be covered with a hood and often include a one-way or hinged flap or a series of hinged flaps secured within a surrounding frame.  
         [0006]     When installing the exhaust vent, it is preferred that the flaps pivot about horizontal axes. In this manner, the flaps will reliably return to a down state when the exhaust air flow through the vent ceases. Otherwise, if mounted in a different orientation, the flaps will not reliably and repeatedly close when the exhaust air flow ceases, i.e., when the clothes dryer has completed the drying cycle.  
         [0007]     Accordingly, installation of exhaust vents involves a leveling process wherein the flaps are mounted to pivot about horizontal axes.  
         [0008]     It is often a problem to level exhaust vents since the flaps are fixed relative to the portion of the exhaust vent mounted to the structure, e.g,, a mounting flange. Thus, in order to ensure that the flaps will pivot about horizontal axes, care must be taken when attaching the mounting flange to the structure. Often though, such care is not exercised and the exhaust vent must either be remounted or the flaps are maintained in a non-ideal orientation.  
       OBJECTS AND SUMMARY OF THE INVENTION  
       [0009]     It is an object of the present invention to provide new and improved vents for enabling a one-way flow of air from a duct leading from an interior of a structure to a location outside of the structure.  
         [0010]     It is another object of the present invention to provide new and improved exhaust vents for mounting to an exterior wall of a structure to provide a one-way flow of exhaust air from a vent member receiving the exhaust air from a clothes dryer to a location exterior of the structure.  
         [0011]     It is yet another object of the present invention to provide exhaust vents which are self-leveling in that they can be leveled to cause one or more flaps thereof to pivot about horizontal axes regardless of the manner and orientation in which the vents are attached to a structure.  
         [0012]     Accordingly, to achieve these objects and others, one embodiment of a vent for a duct terminating proximate a wall of a structure in accordance with the invention includes a first member adapted to be connectable to the wall in engagement with the duct, a second member rotatably connected to the first member and adapted to be arranged in front of the wall and at least one flap pivotally mounted to the second member such that upon rotation of the second member relative to the first member, a pivot axis of each flap is adjustable, e.g., to provide a horizontal pivot axis. The flap or flaps cover an opening at the end of the duct. In this manner, even though the first member is mounted to the wall, usually fixed to the wall, the second member is rotatable relative thereto and this relative rotation enables the orientation or pivot axis of the flap(s) to be adjustable. Accordingly, the first member can be mounted to the wall without concern as to how the flap(s) will be oriented. This self-leveling feature greatly simplifies the installation of the vent.  
         [0013]     The first member may be a mounting flange including an attachment mechanism for enabling its attachment to the wall and/or the duct. For example, the mounting flange may include an annular wall or portion which lies flush against the inner or outer surface of the wall and includes holes through which screws can be drilled into the wall. Another attachment mechanism constitutes coaxial cylindrical walls formed on a rear side of the mounting flange with a clearance therebetween designed to snugly accommodate the terminal end of the duct.  
         [0014]     The second member may be a trim flange which covers the mounting flange and has decorative trim thereon. The trim flange may include a connecting mechanism for rotatably connecting it to the mounting flange. For example, the connecting mechanism might be flexible snap fingers arranged on a substantially cylindrical wall of the trim flange to engage with a cylindrical wall of the mounting flange.  
         [0015]     In another embodiment, the second member serves as a cover having a defined interior in which the flap(s) is/are situated and includes openings for the air flow therethrough. Such a cover prevents small animals from entering into the duct through the vent when the flap(s) are open. The mounting flange may be connected to the cover member by flexible snap fingers arranged on a rim of the mounting flange to engage with and secure a rim of the cover member. As the number of flaps is increased (and the length of each flap is thereby reduced), it becomes possible to reduce the depth of the cover member.  
         [0016]     Another embodiment of a vent for a duct terminating proximate a wall in accordance with the invention includes a mounting flange adapted to be connectable to the wall in engagement with the duct, a sleeve member rotatably connected to the mounting flange, a lint grill connected to the sleeve member and adapted to extend across the opening of the duct, a flap plate frame pressed against the wall by the sleeve member such that the flap plate frame is rotatable relative to the sleeve member until the sleeve member is tightly engaged with the mounting flange and a flap pivotally mounted to the flap plate frame. With this structure, upon rotation of the flap plate frame prior to tight engagement of the sleeve member with the mounting flange, a pivot axis of the flap is adjustable, e.g., to provide the flap with a horizontal pivot axis.  
         [0017]     The sleeve member may be removably connected to the mounting flange by arranging cooperating threads on an inner surface of the mounting flange and on an outer surface of the sleeve member. Coarse threads may be provided to reduce the number of turns required to thread the sleeve member into the mounting flange.  
         [0018]     To enable the flap plate frame to be pressed against the wall upon rotation of the sleeve member into the mounting flange, the sleeve member includes a peripheral, outwardly directed rim formed at a front edge and the flap plate frame includes an annular seat for receiving the peripheral rim.  
         [0019]     Another embodiment of a vent for a duct terminating proximate a wall in accordance with the invention includes a mounting flange adapted to be engaged with the duct, a trim flange engaged with the mounting flange including at least one disc portion having openings and a rotary disc rotatably mounted to each disc portion of the trim flange. Each rotary disc is rotatable relative to the trim flange to vary correspondence between openings in the rotary disc and the openings in the respective disc portion of the trim flange and thereby vary flow through the vent.  
         [0020]     This vent thus provides controlled flow obtained by rotating the rotary discs relative to the trim flange. The rotary discs also include parallel vanes to enable the vent to control the direction of the flow of air therethrough.  
         [0021]     The trim flange includes a cylindrical wall arranged in engagement with a cylindrical wall of the mounting flange to secure the trim flange to the mounting flange. Specifically, the trim flange includes a center axle, spokes extending inward from a rear, peripheral edge of the cylindrical wall thereof to the center axle and a spring arm attached to each spoke. The spring arms exert pressure against the cylindrical wall of the mounting flange when the trim flange is engaged with the mounting flange.  
         [0022]     Other and further objects, advantages and features of the present invention will be understood by reference to the following specification in conjunction with the annexed drawings, wherein like parts have been given like numbers. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0023]     The invention, together with further objects and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings, wherein like reference numerals identify like elements, and wherein:  
         [0024]      FIG. 1  is a perspective view of a first embodiment of an exhaust vent in accordance with the invention.  
         [0025]      FIG. 2  is a cross-sectional view taken along the line  2 - 2  of  FIG. 1 .  
         [0026]      FIG. 3  is a front elevational view of the exhaust vent shown in  FIG. 1 .  
         [0027]      FIG. 4  is an exploded perspective view of the exhaust vent shown in  FIG. 1 .  
         [0028]      FIG. 5  is a perspective view of a second embodiment of an exhaust vent in accordance with the invention.  
         [0029]      FIG. 6  is a cross-sectional view taken along the line  6 - 6  of  FIG. 5 .  
         [0030]      FIG. 7  is a cross-sectional front view taken along the line  7 - 7  of  FIG. 6 .  
         [0031]      FIG. 8  is an exploded perspective view of the exhaust vent shown in  FIG. 5 .  
         [0032]      FIG. 9  is a perspective view of a third embodiment of an exhaust vent in accordance with the invention.  
         [0033]      FIG. 10  is a cross-sectional view taken along the line  10 - 10  of  FIG. 9 .  
         [0034]      FIG. 11  is a cross-sectional front view taken along the line  11 - 11  of  FIG. 10 .  
         [0035]      FIG. 12  is an exploded perspective view of the exhaust vent shown in  FIG. 9 .  
         [0036]      FIG. 13  is a perspective view of a fourth embodiment of an exhaust vent in accordance with the invention.  
         [0037]      FIG. 14  is a cross-sectional view taken along the line  14 - 14  of  FIG. 13 .  
         [0038]      FIG. 15  is a front elevational view of the exhaust vent shown in  FIG. 13 .  
         [0039]      FIG. 16  is an exploded perspective view of the exhaust vent shown in  FIG. 13 .  
         [0040]      FIG. 17  is a perspective view of a fifth embodiment of an exhaust vent in accordance with the invention.  
         [0041]      FIG. 18  is an exploded perspective view of the exhaust vent shown in  FIG. 17 .  
         [0042]      FIG. 19  is a perspective view of a sixth embodiment of an exhaust vent in accordance with the invention.  
         [0043]      FIG. 20  is a cross-sectional side view taken along the line  20 - 20  of  FIG. 19 .  
         [0044]      FIG. 21  is a rear elevational view of the exhaust vent shown in  FIG. 19 .  
         [0045]      FIG. 22  is an exploded perspective view of the exhaust vent shown in  FIG. 19 .  
         [0046]      FIG. 23  is a perspective view of a seventh embodiment of an exhaust vent in accordance with the invention.  
         [0047]      FIG. 24  is a cross-sectional view taken along the line  24 - 24  of  FIG. 23 .  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0048]     Referring to the accompanying drawings wherein like reference numerals refer to the same or similar elements, a first embodiment of an exhaust vent in accordance with the invention is shown in  FIGS. 1-4  and designated generally as  10 . The exhaust vent  10  is designed to engage with an open end of a duct  6  arranged in an aperture of a wall  8  of an exterior structure. For example, the exhaust vent  10  may be used to terminate a vent member arranged in an aperture of an exterior wall of a house and coupled at its inner end to a vent conduit leading from a clothes dryer. However, it is conceivable that the wall  8  may be an inside wall of a building and thus, the term “exterior structure” is used herein to designate any structure exterior to an exhaust gas generating device whereby it is desired to vent the exhaust gas from the generating device to another space exterior to or outside of the space in which the generating device is situated.  
         [0049]     The vent  10  includes a mounting flange  12  which is connected to the wall  8 , a trim flange  14  connected to the mounting flange  12  and flaps  16  pivotally mounted on or to the trim flange  14 . Flaps  16  have a closed position in which they cover the opening of the duct  6  (see the left side of  FIG. 3 ) and an open position in which they are pivoted outward to allow an air flow through the vent  10  (see the right side of  FIG. 3 ). An open position of the flaps  16  is also shown by the phantom lines in  FIG. 2 . The pivotal movement of the flaps  16  to the open position is caused by the air flow through the duct  6  which exerts pressure against the flaps  16  and causes the flaps  16  to pivot upward and outward and allow the air flow through the vent  10 . When the air flow through the duct  6  ceases, the flaps  16  return to their closed position by the effect of gravity. The flaps  16  will also tend to pivot upward and downward upon variations in the air flow through the duct  6 .  
         [0050]     Mounting flange  12  includes an annular portion  18  which is designed to be positioned against the wall  8 , preferably in contact therewith, and an engagement portion  20  which engages with the open end of the duct  6 . Engagement portion  20  includes an outer substantially cylindrical wall  22  and a larger inner substantially cylindrical wall  24  defining a gap therebetween which receives the duct  6  (see  FIG. 2 ).  
         [0051]     An attachment mechanism is provided to attach the mounting flange  12  to the wall  8 . The attachment mechanism may comprise one or more apertures  26  formed in the annular portion  18  and screws  28  which are passed through the apertures  26  into the wall  8  (see  FIG. 2 ). Alternative attachment mechanisms are also envisioned, such as nails which can be nailed through the annular portion  18  into the wall  8 .  
         [0052]     Trim flange  14  is connected to the mounting flange  12  so that the trim flange  14  can be rotated, after engagement with the mounting flange  12 , until the flaps  16  are positioned in a position in which they pivot about horizontal axes. To this end, the trim flange  12  includes a cylindrical portion  30  having flexible snap fingers  32  which secure the trim flange  14  to the mounting flange  12  yet allow rotation of the trim flange  14  relative to the mounting flange  12 . Specifically, the cylindrical portion  30  of the trim flange  14  is designed to fit in an opening defined by the inner cylindrical wall  24  of the mounting flange  12  with the snap fingers  32  engaging a rear edge of the inner cylindrical wall  24  (see  FIG. 2 ).  
         [0053]     Flexible snap fingers  32  are formed by providing two axial cuts  34  in the cylindrical portion  30  and an outwardly directed projection  36  between the cuts  34  (see  FIG. 2 ). Each projection  36  may have an angled front surface  38  to facilitate insertion of the cylindrical portion  30  into the opening defined by the inner cylindrical wall  24  of the mounting flange  12  and passage therethrough (see  FIG. 2 ). In one embodiment, three flexible snap fingers  32  are provided and spaced equiangularly about the cylindrical portion  30 . Instead of snap fingers  32 , other mechanisms for enabling rotation of the trim flange  14  relative to the mounting flange  12  may also be provided, including those disclosed in other embodiments herein to the extent possible.  
         [0054]     Trim flange  14  also includes an annular portion  40  extending from an outer edge of the cylindrical portion  30  and arranged against the annular portion  18  of the mounting flange  12  and a rim  42  surrounding the annular portion  40 . Rim  42  includes an inner wall  44  angled outward from the annular portion  40 , an annular wall  46  connected to an outer edge thereof and a cylindrical outer wall  48  connected to the outer edge of the annular wall  46 . The annular portion  40  and rim  42  are preferably dimensioned to overlie and cover the mounting flange  12  such that the mounting flange  12  is not visible from the front of the vent  10  (see  FIG. 1 ). The entire trim flange  14  may be formed of an integral member.  
         [0055]     To mount the flaps  16  to the trim flange  14 , the inner wall  44  of the rim  42  include pairs of opposite recesses  50 , one pair for each flap  16 , and each flap  16  includes a pair of mounting projections  52  extending from a substantially planar body  54  and which are insertable into a respective pair of recesses  50  in the inner wall  44 . The projections  52  and body  54  are slightly bendable so that the flaps  16  can be bent in order to force the projections  52  into the recesses  50 . Instead of mounting projections  52 , each flap  16  can include a elongate pin with the ends of the pin constituting the mounting projections.  
         [0056]     The projections  52  are rotatable in the recesses  50  to enable the flaps  16  to pivot about pivot axes defined by the projections  52 . Since the pivot axes are preferably parallel to one another, the pairs of recesses  50  are formed such that lines extending through the pairs of recesses  50  are parallel to one another. Thus, the flaps  16  can all pivot about horizontal axes when the trim flange  14  is properly positioned.  
         [0057]     In the illustrated embodiment, the flaps  16  are designed to completely close the open end of the duct  6 . To this end, an upper edge of the uppermost flap  16 , side edges of the intermediate flap  16  and a lower edge of the lowermost flap  16  extend beyond the opening of the duct  6 . Also, the uppermost flap  16  is mounted to pivot about an axis defined entirely alongside the annular portion  40 , and thus this pivot axis will be situated above the top of the opening of the duct  6 . Adjoining edges of the flaps  16  are then designed to engage with one another, e.g., in the form of a half lap joint with a notch  56  being formed at the lower edge of the uppermost and intermediate flaps  16  and a complementary notch  58  being formed at the upper edge of the intermediate and lowermost flaps  16  (see  FIGS. 2 and 4 ). When the flaps  16  are closed, the notches  56  engage notches  58  thereby providing an efficient closure of the duct  6 .  
         [0058]     In addition, each flap  16  includes a peripheral rim  16   a  extending from a rear surface and which is arranged to contact the annular portion  40  of the trim flange  14  (see  FIG. 2 ).  
         [0059]     To install the vent  10 , the first step is to attach the mounting flange  12  to the wall  8 . Attachment of the mounting flange  12  to the wall  8  involves positioning the mounting flange  12  such that the duct  6  is received in the gap between cylindrical walls  22  and  24  and then drilling the screws  28  through apertures  26  into the wall  8 . When attaching the mounting flange  12  to the wall  8 , consideration does not have to be given to the orientation of the mounting flange  12  relative to the duct  6  to ensure that the flaps  16  pivot about horizontal axes since the flaps  16  are not fixed in place based on the orientation of the mounting flange  12 .  
         [0060]     The next step is to connect the trim flange  14  to the mounting flange  12  by inserting the cylindrical portion  30  of the trim flange  14  into the opening defined by the inner cylindrical wall  24  of the mounting flange  12 . During this insertion, the snap fingers  32  flex inward as the angled front surfaces  38  thereof initially contact the inner cylindrical wall  24  and then slide along the inner surface of the inner cylindrical wall  24 . At the inner axial end of the inner cylindrical wall  24 , the snap fingers  32  snap outward to thereby secure the trim flange  14  to the mounting flange  12 . Removal of the trim flange  14  from engagement with the mounting flange  12  is prevented by the engagement of the projections  36  of the snap fingers against the rear edge of the inner cylindrical wall  24 . However, the projections  36  are rotatable along the rear edge of the inner cylindrical wall  24  so that the trim flange  14  is rotatable relative to the mounting flange  12 .  
         [0061]     The flaps  16  may be snapped into the trim flange  14  by pressing the projections  50  of each flap  16  into the respective pair of recesses  48  either before or after the trim flange  14  is connected to the mounting flange  12 . When different shaped flaps  16  are used as in the illustrated embodiment, care must be exercised to place each flap  16  in its appropriate position in the trim flange  14 .  
         [0062]     The final step is to orient the flaps  16  such that they pivot about horizontal axes. This is accomplished by grasping the trim flange  14 , e.g., the rim  42  thereof, and rotating it to thereby “level” the flaps  16  and attain the desired position. The flaps  16  will thus pivot outward about horizontal axes upon flow of air through the duct  6  and will reliably return to a position closing the duct  6  when the air flow ceases.  
         [0063]     A second embodiment of an exhaust vent in accordance with the invention is shown in  FIGS. 5-8  and designated generally as  60 . Vent  60  includes a mounting flange  62  which is connected to the wall  8 , a cover member  64  connected to the mounting flange  62  and a flap  66  pivotally mounted on the cover member  64 . Flap  66  has a closed position in which it covers the opening of the duct  6  (see the flap  66  in solid lines in  FIG. 6  and  FIG. 7 ) and an open position in which it is pivoted outward to allow flow of air through the vent  60  (see the flap  66  in phantom lines in  FIG. 6 ). The air flow through the duct  6  exerts pressure against the flap  66  and causes it to pivot outward and allow the air flow through the vent  60 . When the air flow through the duct  6  ceases, the flap  66  returns to its closed position by the effect of gravity.  
         [0064]     Mounting flange  62  includes an annular portion  68  which is designed to be positioned against the wall  8 , preferably in contact therewith, an engagement portion  70  which engages with the end of the duct  6 , and a rim  72  which is connectable with the cover member  64 . Engagement portion  70  includes an outer cylindrical wall  74  and a larger inner cylindrical wall  76  defining a gap therebetween which receives the duct.  6  (see  FIG. 6 ).  
         [0065]     An attachment mechanism is provided to attach the mounting flange  62  to the wall  8 , for example, apertures  78  formed in the annular portion  68  and screws  28  which are passed through the apertures  78  into the wall  8  (see  FIG. 6 ). Alternative attachment mechanisms are also envisioned, such as nails which can be nailed through the annular portion  68  into the wall  8 .  
         [0066]     Rim  72  is substantially cylindrical and includes flexible snap fingers  80  which secure the cover member  64  to the mounting flange  62  yet allow rotation of the cover member  64  relative to the mounting flange  62 . Cover member  64  is thus rotatably connected to the mounting flange  62 . In this manner, once the mounting flange  62  is secured to the wall  8 , the cover member  64  can be connected to the mounting flange  62  with the flap  66  in any orientation and then the cover member  64  rotated to position and “level” the flap  66  until the flap  66  is in a position in which it will pivot about a horizontal axis.  
         [0067]     Each snap finger  80  is formed by providing two axial cuts  82  in the rim  72  and an outwardly directed projection  84  between the cuts  82  (see  FIG. 8 ). Each projection  84  preferably includes an angled front surface  86  to facilitate insertion of the cover member  64  into engagement with the mounting flange  62  (see  FIG. 6 ). In one embodiment, three snap fingers  80  are provided and spaced equiangularly about the rim  72  (see  FIG. 8 ). Instead of snap fingers  80 , other mechanisms for coupling the cover member  64  to the mounting flange  62  while enabling rotation of the cover member  64  relative to the mounting flange  62  may also be provided, including those disclosed in other embodiments herein to the extent possible.  
         [0068]     Cover member  64  includes an engagement rim  88  arranged to be secured by the snap fingers  80  between the snap fingers  82  and the annular portion  68  of the mounting flange  62 , and a hood portion  90  having an upper closed section  92  and a lower apertured section  94  to allow air flow therethrough. The hood portion  90  limits the outward pivoting of the flap  66 . The shape of the hood portion  90  and the relative position and size of the closed section  92  and apertured section  94  (and apertures thereof) may vary depending on the particular design desired.  
         [0069]     Cover member  64  also includes mounting brackets  96  which define holes  98  which receive pins  100  of the flap  66  and slots  102  leading into the holes  98 . Pins  100  are inserted into the holes  98  through slots  102  prior to connection of the cover member  64  to the mounting flange  62 .  
         [0070]     Flap  66  includes a substantially planar body  104  defining the pins  100  and a cylindrical spacing projection  106  arranged on a rear surface of the body  104 . When the flap  66  is in a position in which the opening of the duct  6  is closed, the spacing projection  106  abuts against the annular portion  68  of the mounting flange  62  (see  FIG. 6 ).  
         [0071]     To install the vent  60 , the first step is to attach the mounting flange  62  to the wall  8 . This involves positioning the mounting flange  62  such that the duct  6  is received in the gap between cylindrical walls  72  and  74  and then drilling the screws  28  through apertures  78  in the annular portion  68  of the mounting flange  62  into the wall  8 . When attaching the mounting flange  62  to the wall  8 , consideration does not have to be given to the orientation of the mounting flange  62  relative to the duct  6  to ensure that the flap  66  pivots about a horizontal axis since the flap  66  is connected to the trim flange  64  which is rotatable relative to the mounting flange  62 .  
         [0072]     If the flap  66  is not previously attached to the cover member  64 , then it is now attached by rotating the flap  66  ninety degrees from the position shown in  FIG. 8  such that the pins  100  can be inserted through the slots  102  into the holes  98  in the mounting brackets  96 . Once the pins  100  are situated in the holes  98 , the flap  66  is rotated into a position in which it hangs on the mounting brackets  96 , i.e., in a position in which the body  104  is perpendicular to a central axis of the cover member  64  as shown most clearly in  FIG. 6 .  
         [0073]     The next step is to connect the cover member  64 , with the attached flap  66 , to the mounting flange  62  by inserting the engagement rim  88  of the cover member  64  into engagement with the mounting flange  62 . During this insertion, the snap fingers  80  flex outward as the angled front surfaces  86  thereof are contacted by the engagement rim  88  of the cover member  64 . The snap fingers  80  slide along the outer surface of the engagement rim  88  until, at the outer axial end of the engagement rim  88 , the snap fingers  80  snap inward to thereby secure the rim  88  in connection with the mounting flange  62  (see  FIGS. 6 and 7 ). However, since the snap fingers  80  only prevent separation of the engagement rim  88  from the rim  72  of the mounting flange  62  and not rotation thereof, the cover member  64  is rotatable relative to the mounting flange  62 .  
         [0074]     The final step in the installation procedure is to orient the flap  66  such that it pivots about a horizontal axis. This is accomplished by grasping the cover member  64 , e.g., the hood portion  90  thereof, and rotating it to thereby “level” the flap  66  and attain the desired orientation in which the flap  66  pivots about a horizontal axis. The flap  66  will thus pivot outward upon flow of air through the duct  6  and will reliably return to a position closing the opening of the duct  6  when the air flow ceases.  
         [0075]     A third embodiment of an exhaust vent in accordance with the invention is shown in  FIGS. 9-12  and designated generally as  110 . Vent  110  includes a mounting flange  112  which is connected to the wall  8 , a cover member  114  connected to the mounting flange  112  and flaps  116 A,  116 B pivotally mounted to the cover member  114 . Flaps  116 A,  116 B have a closed position in which they cover the opening of the duct  6  (see the flaps  116 A,  116 B in solid lines in  FIG. 10  and  FIG. 11 ) and an open position in which they are pivoted outward to allow air flow through the vent  110  (see the flaps  116 A,  116 B in phantom lines in  FIG. 10 ). An air flow through the duct  6  exerts pressure against the flaps  116 A,  116 B and causes them to pivot outward and allow the air flow through the vent  110 . When the air flow through the duct  6  ceases, the flaps  116 A,  116 B return to their closed position by the effect of gravity.  
         [0076]     Mounting flange  112  includes an annular portion  118  which is designed to be positioned against the wall  8 , preferably in contact therewith, an inner cylindrical wall  120  extending to both sides of the annular portion  118  and a rim  122  which is connectable to the cover member  114 . An outer cylindrical wall  124  is arranged around the inner wall  120  on a rear side of the annular portion  118 . The inner and outer walls  120 ,  124  define a gap therebetween which engages with and receives the end of the duct  6  (see  FIG. 10 ).  
         [0077]     An attachment mechanism is provided to attach the mounting flange  112  to the wall  8 , for example, apertures  126  formed in the annular portion  118  and screws which are passed through the apertures  126  into the wall  8 . Alternative attachment mechanisms are also envisioned.  
         [0078]     Rim  122  is substantially cylindrical and includes flexible snap fingers  80 , described above. Cover member  114  is rotatably connected to the mounting flange  112  via the snap fingers  80  so that once the mounting flange  112  is secured to the wall  8 , the cover member  114  can be rotated to level the flaps  116 A,  116 B, i.e., to position the flaps  116 A,  116 B in a position in which they pivot about horizontal axes. Instead of snap fingers  80 , other mechanisms for enabling rotation of the cover member  114  relative to the mounting flange  112  may also be provided, including those disclosed in other embodiments herein to the extent possible.  
         [0079]     Cover member  114  includes an engagement rim  128  arranged to be secured by the snap fingers  80  between the snap fingers  80  and the annular portion  118  of the mounting flange  112 , and a hood portion  130  having an upper closed section  132  and a lower apertured section  134  to allow air flow therethrough. The hood portion  130  limits the outward pivoting of the flaps  116 A,  116 B. The shape of the hood portion  130  and the relative position and size of the closed section  132  and apertured section  134  (including the apertures thereof) may vary depending on the particular design desired.  
         [0080]     In contrast to the embodiment shown in  FIGS. 5-8 , in this embodiment, there are two flaps  116 A,  116 B instead of a single flap  66  so that the size of each flap  116 A,  116 B is approximately half the size of the flap  66  (for the same size duct  6 ). Therefore, since the extension of the flaps  116 A,  116 B when pivoted outward is less than the extension of the flap  66  when pivoted outward, a reduced clearance in the interior of the hood portion  130  is required to allow the flaps  116 A,  116 B to open fully. The hood portion  130  can therefore be designed with a lower depth than the depth of the hood portion  90  (D 2 &lt;D 1 ). Generally, as the number of flaps increases, the extension of each flap when pivoted outward decreases so that a hood portion with a lower depth can be provided (for the same size duct  6 ).  
         [0081]     Cover member  114  also includes pairs of mounting brackets  136  which define holes  138  which receive cylindrical pins  140  of the flaps  116 A,  116 B and slots  142  leading into the holes  138 . The slots  142  on the mounting brackets  136  of the cover member  114  are formed to enable insertion of the pins  140  of the flaps  116 A,  116 B into the holes  138  prior to connection of the cover member  114  to the mounting flange  112 .  
         [0082]     Reinforcing ribs  152  are arranged between the mounting brackets  136  and the lateral sides of the hood portion  130  of the cover member  114  to reinforce the mounting brackets  136  when they are apart from the lateral sides of the hood portion  130 .  
         [0083]     Each flap  116 A,  116 B includes a substantially planar body  144  with the pins  140  projecting outward to sides of the body  144 . A recess  146  is formed on the rear surface of the body  144 . When each flap  116 A,  116 B is in a position in which the opening of the duct  6  is closed, the body  144  abuts against the cylindrical wall  120  of the mounting flange  112  (see  FIG. 10 ).  
         [0084]     In the illustrated embodiment, the flaps  116 A,  116 B are designed to completely close the open end of the duct  6 . To this end, an upper edge of the flap  116 A, side edges of the flaps  116 A,  116 B and a lower edge of the flap  116 B extend beyond the opening defined by the cylindrical wall  120 . Also, adjoining edges of the flaps  116 A,  116 B are designed to engage with one another, e.g., in the form of a half lap joint with a notch  148  being formed at the lower edge of the flap  116 A and a complementary notch  150  being formed at the upper edge of the flap  116 B (see  FIGS. 10 and 12 ). When the flaps  116 A,  116 B are closed, the notch  148  engages notch  150  thereby providing an efficient closure of the duct  6 .  
         [0085]     In an alternative construction of the flaps  116 A,  116 B, each flap can comprise an elongate cylindrical portion whose ends constitute the pin  140  and a planar portion which is attached to the cylindrical portion.  
         [0086]     To install the vent  110 , the first step is to attach the mounting flange  112  to the wall  8 . This involves positioning the mounting flange  112  such that the duct  6  is received in the gap between cylindrical walls  120  and  124  and then placing screws through apertures  126  in the annular portion  118  of the mounting flange  112  and screwing or drilling them into the wall  8 . When attaching the mounting flange  112  to the wall  8 , consideration does not have to be given to the orientation of the mounting flange  112  relative to the duct  6  to ensure that the flaps  116 A,  116 B pivot about horizontal axes since the flaps  116 A,  116 B are connected to the trim flange  114  which is rotatable relative to the mounting flange  112 .  
         [0087]     If the flaps  116 A,  116 B are not previously attached to the cover member  114 , then they are now attached by pushing the pins  140  through the slots  142  into the holes  138  in the respective pair of mounting brackets  136 .  
         [0088]     The next step is to connect the cover member  114 , with the attached flaps  116 A,  116 B, to the mounting flange  112  by inserting the engagement rim  128  of the cover member  114  into engagement with the mounting flange  112 . During this insertion, the snap fingers  80  flex outward as the angled front surfaces  86  thereof are contacted by the engagement rim  128  of the cover member  114 . The snap fingers  80  slide along the outer surface of the engagement rim  128  until, at the outer axial end of the engagement rim  128 , the snap fingers  80  snap inward to thereby secure the rim  128  in connection with the mounting flange  112  (see  FIGS. 10 and 11 ). However, since the snap fingers  80  only prevent separation of the engagement rim  128  from the rim  122  of the mounting flange  112  and not rotation thereof, the cover member  114  is rotatable relative to the mounting flange  112 .  
         [0089]     The final step in the installation procedure is to orient the flaps  116 A,  116 B such that they pivot about horizontal axes. This is accomplished by grasping the cover member  114 , e.g., the hood portion  130  thereof, and rotating it to thereby “level” the flaps  116 A,  116 B and attain the desired orientation in which the flaps  116 A,  116 B pivot about horizontal axes. The flaps  116 A,  116 B will thus pivot outward upon flow of air through the duct  6  and will reliably return to a position closing the opening of the duct  6  when the air flow ceases.  
         [0090]     A fourth embodiment of an exhaust vent in accordance with the invention is shown in  FIGS. 13-16  and designated generally as  160 . This embodiment of the vent  160  differs generally from the embodiments described above in that the mounting flange is mounted to an inner side of the wall  8 .  
         [0091]     Vent  160  includes a mounting flange  162  which is connected to the wall  8 , a generally cylindrical sleeve member  164  removably connected to the mounting flange  162 , a lint grill  166  connected to the sleeve member  164  and adapted to extend across the opening of the duct  6 , a flap plate frame  168  which is pressed against the wall  8  by the sleeve member  164  and a flap  170  pivotally mounted to the flap plate frame  168 . Flap  170  has a closed position in which it covers the lint grill  166  (see the flap  168  in solid lines in  FIG. 14 ) and an open position in which it is pivoted outward to allow air flow through the lint grill  166  (see the flap  170  in phantom lines in  FIG. 14 ). An air flow through the duct  6  and lint grill  166  exerts pressure against the flap  170  and causes it to pivot outward and allow the air flow through the vent  160 . When the air flow through the duct  6  ceases, the flap  170  returns to its closed position by the effect of gravity.  
         [0092]     Mounting flange  162  includes an annular portion  172  which is designed to be positioned against an inner surface of the wall  8 , preferably in contact therewith, and a cylindrical wall  174  extending to both sides of the annular portion  172 . Cylindrical wall  174  is dimensioned to fit within the open end of the duct  6 , preferably with as small a clearance as possible. Since the annular portion  172  is preferably flush against the inner surface of the wall  8 , the duct  6  terminated by the vent  160  does not pass through the aperture in the wall  8 . Optionally, a second cylindrical wall can be formed around the cylindrical wall  174  on a rear side of the annular portion  172  to define a gap therebetween which engages with and receives the end of the duct  6  (in the same manner as described above).  
         [0093]     An attachment mechanism is provided to attach the mounting flange  162  to the wall  8 , for example, apertures  176  formed in the annular portion  172  and screws which are passed through the apertures  176  into the wall  8 . Alternative attachment mechanisms are also envisioned.  
         [0094]     Another attachment mechanism is provided to enable the sleeve member  164  to be removably attached to the mounting flange  162 . Specifically, threads  178  are formed on an inner surface of the cylindrical wall  174  and engage with threads  180  formed on an outer surface of the sleeve member  164  (see  FIG. 14 ). Thus, once the mounting flange  162  is fixed to the wall  8 , the sleeve member  164  is rotatable relative thereto in view of the cooperating threads  178 ,  180 . Threads  178 ,  180  may be a coarse screw thread connection.  
         [0095]     The sleeve member  164  also includes a peripheral, outwardly directed rim  182  formed at a front edge and a circumferential raised portion  184  formed on an inner surface proximate the peripheral rim  182 .  
         [0096]     To connect the lint grill  166  to the sleeve member  164 , the lint grill  166  includes flexible snap fingers  186  extending rearward from a rear surface which snap around the raised portion  184  of the sleeve member  164 . Each snap finger  186  includes an angled rearward facing surface  188  to facilitate passage of the lint grill  166  over the raised portion  184  of the sleeve member  164  (see  FIG. 14 ). In the illustrated embodiment, four snap fingers  186  are provided spaced equiangularly around the circumference of the lint grill  166 . However, any number of snap fingers  186  may be provided and other mechanisms for attaching the lint grill  166  to the sleeve member  164  are also possible.  
         [0097]     Anti-rotation lugs  190  are formed on the raised portion  184  of the sleeve member  164  with each snap finger  186  being received between a pair of lugs  190 . In view of the positioning of the snap fingers  186  between the lugs  190 , rotation of the lint grill  166  causes rotation of the sleeve member  164 . The lint grill  166  is more easily rotatable since the installer can insert his or her fingers into the apertures in the lint grill  166  and rotate the lint grill  166  which causes rotation of the sleeve member  164 . By contrast, rotation of the sleeve member  164  directly is more difficult since the peripheral rim  182  must be grasped and rotated.  
         [0098]     To secure the flap plate frame  168  to the outer surface of the wall  8 , the flap plate frame  168  includes an annular seat  192  in which the peripheral rim  182  of the sleeve member  164  is received (see  FIG. 14 ). The flap plate frame  168  is thus pressed against the outer surface of the wall  8  as the sleeve member  164  is rotated into the mounting flange  162 .  
         [0099]     The flap plate frame  168  also includes an annular wall  194  surrounding the seat  192 , a rim  196  extending rearward from an outer circumferential edge of the annular wall  194  and a cylindrical wall  198  extending inward from an inner edge of the annular wall  194 . Cylindrical wall  198  is arranged around the seat  192  and is adapted to be positioned in the aperture defined by the wall  8  (see  FIG. 14 ). The sleeve member  164  is arranged in the cylindrical wall  198 .  
         [0100]     To mount the flap  170  to the flap plate frame  168 , a cavity  200  is formed in the annular wall  194  and is defined by opposed walls  202  with each wall  202  including an aperture  204 . A pin  206  is passed through apertures  208  in side walls  210  of a mounting portion  212  of the flap  170  and positioned into the apertures  204  to thereby pivotally mount the flap  170  to the flap plate frame  168 .  
         [0101]     Flap  170  includes a substantially planar body  214  with the mounting portion  212  extending on one side thereof and a cylindrical spacing projection  216  arranged on a rear surface of the body  214 . When the flap  170  is in a position in which the opening of the duct  6  is closed, the spacing projection  216  abuts against the peripheral rim  182  of the sleeve member  164  (see  FIG. 14 ).  
         [0102]     To install the vent  160 , the mounting flange  162  is attached to the wall  8 . This involves positioning the mounting flange  162  such that the cylindrical wall  174  is received inside the duct  6 , positioning the mounting flange  162  against an inner surface of the wall  8  and then placing screws through apertures  176  in the annular portion  172  of the mounting flange  162  and screwing or drilling them into the wall  8 .  
         [0103]     The lint grill  166  is then attached to the sleeve member  164  by pushing the snap fingers  182  between the lugs  190 . The flap frame plate  168  is then positioned against the outer surface of the wall  8  with its cylindrical wall  198  around the cylindrical wall  174  of the mounting flange  162 . Sleeve member  164  is passed through the cylindrical wall  198  of the flap plate frame  168  and rotated into connection with the mounting flange  162  via the cooperating threads  178 ,  180 . At this time, the peripheral rim  182  of the sleeve member  162  is situated in the seat  192  of the flap plate frame  168 . Rotation of the sleeve member  164  may be facilitated by inserting fingers through the apertures in the lint grill  166  and rotating the lint grill  166 .  
         [0104]     If the flap  170  is not previously attached to the flap plate frame  168 , then it is now attached by inserting the pin  206  through the apertures  208  in the side walls  210  of the mounting portion  212  and then urging the pin  206  into the apertures  204  in the side walls  202  in the flap plate frame  168 .  
         [0105]     The next step in the installation procedure is to orient the flap  170  such that it pivots about a horizontal axis. This is accomplished by grasping the flap plate frame  168  or flap  170  and holding it such that pin  206  is parallel to a horizontal surface. At the same time, rotation of the sleeve member  164  into engagement with the mounting flange  162  is completed to thereby tightly secure the sleeve member  164  to the mounting flange  162  and the flap plate frame  168  snug against the outer surface of the wall  8 . Rotation of the flap plate frame  168  will be prevented since the flap plate frame  168  is pressed against the wall  8  by the sleeve member  164 , i.e., sandwiched between the sleeve member  164  and the wall  8 . Proper placement of the lugs  190  will result in the lint grill  168  being situated at the orientation shown in  FIG. 15 .  
         [0106]     In this embodiment, the lint grill  166  may be removable by disengaging it from the sleeve member  164  without affecting the remaining mounting connections, to enable a variety of lint grills  166  to be used, e.g., a lint grill with a fine mesh or a lint grill with a coarse mesh.  
         [0107]     Alternatively, it is possible to form the lint grill  166  and sleeve member  164  as an integral unit, i.e., as a one-piece construction.  
         [0108]     Another embodiment of an exhaust vent in accordance with the invention is shown in  FIGS. 17 and 18  and designated generally as  220 . This embodiment of the vent  220  differs from the embodiment shown in  FIGS. 13-16  in that the flap and flap plate frame are shaped differently. However, the same reference numerals of the embodiment shown in  FIGS. 13-16  will be used for the same elements in the embodiment shown in  FIGS. 17 and 18 . Thus, the vent  220  includes the mounting flange  162 , sleeve member  164  and lint grill  166  as described above.  
         [0109]     Vent  220  also includes a flap plate frame  222  which is pressed against the wall  8  by the sleeve member  164  and a flap  224  pivotally mounted to the flap plate frame  222 . To secure the flap plate frame  222  against the outer surface of the wall  8 , the flap plate frame  222  includes an annular seat  226  in which the peripheral rim  182  of the sleeve member  164  is received. The flap plate frame  222  is thus pressed against the outer surface of the wall  8  as the sleeve member  164  is rotated into the mounting flange  162 .  
         [0110]     The flap plate frame  168  includes a rectangular, peripheral wall  228  including two rectangular depressions  230 ,  232 , a rim  234  extending rearward from an outer circumferential edge of the rectangular wall  228  (on all four sides of the rectangular wall  228 ), and a cylindrical wall  236  extending inward from an inner edge of the rectangular wall  228 . Cylindrical wall  228  is arranged around the seat  226  and is adapted to be positioned in the aperture defined by the wall  8 . The sleeve member  164  is arranged in the cylindrical wall  228 .  
         [0111]     The formation of the depressions  230  on the rectangular wall  228  is substantially for decoration purposes only and various other decorative designs can be formed on the rectangular wall  228 . However, the innermost depression  232  is designed to accommodate the flap  224  so that the depression  232  should have the same shape as the flap  224 . In addition, the shape of the flap plate frame  222  as a rectangle can be varied, i.e., the flap plate frame  228  can be in the shape of an oval, a square and other geometric shapes. Thus, in an alternative construction, an oval flap plate frame can be formed with an oval depression and used with an oval flap.  
         [0112]     The flap  224  also has a decorative form including lateral channels  238  defining three sections. Any number of channels  238  can be formed on the flap  224 .  
         [0113]     To mount the flap  224  to the flap plate frame  222 , opposed side walls  240  defining the depression  232  are each provided with an aperture  242 . Projections  244  are formed on lateral sides of the flap  224  and are positioned in the apertures  242  to thereby pivotally mount the flap  224  to the flap plate frame  222 .  
         [0114]     Installation of the vent  220  is essentially the same as the installation of vent  160  as described above. However, the flap  224  is engaged with the flap plate frame  222  by urging the projections  244  into the apertures  242  on the side walls  240  defining the depression  232  of the flap plate frame  222 . Leveling of the flap  224  can now be performed by leveling the flap plate frame  222 .  
         [0115]     A sixth embodiment of an exhaust vent in accordance with the invention is shown in  FIGS. 19-22  and designated generally as  250 . This embodiment of the vent  250  provides for control over the flow of air therethrough and direction of the flow of air from the vent  250 .  
         [0116]     Vent  250  includes a one-way washer  252  adapted to be positioned on an inner side of the wall  8 , a mounting flange  254  which passes through the washer  252 , a trim flange  256  engaged with the mounting flange  254  and a rotary disc  258  attached to the trim flange  256 .  
         [0117]     The washer  252  includes an annular portion  260  and a plurality of fingers  262  extending inward from the annular portion  260 . The fingers  262  are designed to engage with a cylindrical wall  264  of the mounting flange  254  at an angle to provide a ratcheting effect and prevent removal of the mounting flange  254  after installation of the vent  250 .  
         [0118]     In addition to the cylindrical wall  264 , the mounting flange  254  includes an annular portion  266  extending outward from an outer, peripheral edge of the cylindrical wall  264  and which is designed to be positioned against an outer surface of the wall  8 , preferably in contact therewith. Cylindrical wall  264  is dimensioned to fit within the open end of the duct  6 , preferably with as small a clearance as possible.  
         [0119]     An optional attachment mechanism is provided to attach the mounting flange  254  to the wall  8 , for example, apertures  268  are formed in the annular portion  266  and screws can be passed through the apertures  268  into the wall  8 . Alternative attachment mechanisms are also envisioned.  
         [0120]     Trim flange  256  includes a cylindrical wall  270  and an annular wall  272  having a cross-sectional shape of a semi-circle connected to an outer edge of the cylindrical wall  270 . Cylindrical wall  270  is situated in the cylindrical wall  264  of the mounting flange when the vent  250  is assembled. Trim flange  256  also includes three spokes  274  extending inward from a rear, peripheral edge of the cylindrical wall  270  to a center axle  276  and spaced equiangularly around the peripheral edge of the cylindrical wall  270 .  
         [0121]     To engage the trim flange  256  with the mounting flange  254 , a spring arm  278  is attached, e.g., by a screw  280 , to the radially outward end of each spoke  274  and the spring arms  278  pressingly contact an inner surface of the cylindrical wall  264  of the mounting flange  254  (See  FIG. 20 ). The spring arms  278  are shaped to allow easy entry of the cylindrical wall  270  of the trim flange  256  into the cylindrical wall  264  of the mounting flange  254 . Also, to ensure that the spring arms  278  are placed in appropriate positions to engage with the trim flange  256 , a locator pin  304  is arranged on each spoke  274  and the spring arms  278  are positioned to contact the locator pins  304 .  
         [0122]     Instead of the spring arms  278 , alternative mechanisms for engaging the trim flange  256  to the mounting flange  254  can also be used in this embodiment, including those constructions described above. For example, one of the annular portion  266  of the mounting flange  254  and the annular wall  272  of the trim flange  256  could be provided with snap fingers and the other provided with a cooperating structure to engage with the snap fingers to retain the trim flange  256  in connection with the mounting flange  254 . In the construction of  FIG. 20 , when the spring arms  278  are not provided, then it becomes possible to eliminate the spokes  274  and the center axle  276  from the trim flange  256 .  
         [0123]     Trim flange  256  also includes a disc portion  282  extending across the opening defined by the cylindrical wall  270 . Disc portion  282  includes spokes  284  and openings  286  therebetween. The trim flange  256  may be formed as an integral structure.  
         [0124]     Rotary disc  258  includes a cylindrical rim  288 , a disc portion  290  extending from a rear edge of the rim  288  and a plurality of parallel vanes  292  extending across a space defined by the rim  288 . The disc portion  290  includes spokes  294  and openings  296  therebetween.  
         [0125]     The rotary disc  258  is attached to the disc portion  282  of the trim flange  254  by an appropriate attachment mechanism such as by inserting a screw  298  through aligning apertures in the disc portion  290  of the rotary disc  258  and the disc portion  282  of the trim flange  254  and threading a nut  300  onto the end of the screw  298  (see  FIG. 20 ). The nut  300  is fastened but not tightened so that rotation of the rotary disc  258  relative to the disc portion  282  is possible.  
         [0126]     Alternative attachment mechanism for attaching the rotary disc  258  to the disc portion  282  which enable the rotary disc  258  to rotate relative to the disc portion  282  are also envisioned. For example, the spokes  274  and center axle  276  may be provided to enable a screw to be inserted through the aligning apertures in the rotary disc  258  and the disc portion  282  of the trim flange  256  into engagement with a threaded aperture  306  in the center axle  276 . Thus, the spokes  274  and center axle  276  can be provided to support the spring arms  278  and/or enable rotatable attachment of the rotary disc  258  to the trim flange  256 . Nevertheless, the spokes  274  and center axle  276  can be eliminated when the spring arms  278  are eliminated and the rotary disc  258  is attached to the trim flange  256  using the screw  298  and nut  300 .  
         [0127]     A foam rubber ring  302  is arranged inside the annular wall  272  of the trim flange  256  and against the annular portion  266  of the mounting flange  254  when the trim flange  256  is engaged with the mounting flange  254 . The ring  302  limits the penetration of the trim flange  256  into the cylindrical wall  264  of the mounting flange  254 . The ring  302  may have a cut in it to enable it to be placed in a cavity defined by the annular wall  272  and may also be shaped to conform to the shape of the inner surface of the annular wall  272 .  
         [0128]     To install the vent  250 , the washer  252  is placed around the opening in the wall  8  on an inner side thereof and the cylindrical wall  264  of the mounting flange  254  is passed from the exterior of the wall  8  through the opening therein and into engagement with the washer  252 . The fingers  262  on the washer  252  are urged rearward (as shown in  FIG. 20 ) and this inhibits removal of the mounting flange  254  from the wall  8 . If a more secure attachment of the mounting flange  254  to the wall  8  is desired, screws can be placed in the apertures  268  in the annular portion  266  of the mounting flange  254  and drilled or screwed through the exterior surface of the wall  8 .  
         [0129]     The rotary disc  258  is attached to the disc portion  282  of the trim flange  254 , e.g., by inserting the screw  298  through aligning apertures in the disc portion  290  of the rotary disc  258  and the disc portion  282  of the trim flange  254  and threading the nut  306  onto the end of the screw  298 . The nut  300  is fastened but not tightened so that rotation of the rotary disc  258  relative to the disc portion  282  is possible.  
         [0130]     The trim flange  256 , with attached rotary disc  258 , is then placed into engagement with the mounting flange  254  by inserting the cylindrical wall  270  of the trim flange  256  into the cylindrical wall  264  of the mounting flange  254 . The spring arms  278  engage with the cylindrical wall  264  and exert pressure against the cylindrical wall  264  to fix the trim flange  256  in position. In conjunction with this engagement, the ring  302  is placed between the mounting flange  254  and the trim flange  256 .  
         [0131]     The final step in the installation procedure is to orient the rotary disc  258  to provide the desired flow of air and direction thereof. The rotary disc  258  is rotated relative to the trim flange  256  to vary the correspondence between the openings  296  between the spokes  294  of the rotary disc  258  and the openings  286  between the spokes  286  of the disc portion  282  of the trim flange  256 . If the openings  286  and  296  are in complete correspondence, a maximum flow of air will be provided by the vent  250  whereas if the openings  296  of the rotary disc  258  align with the spokes  284  of the disc portion  282 , there will not be any flow of air through the vent  250 . Between these two extreme positions, any desired position can be selected.  
         [0132]     When the rotary disc  258  is rotated, the vanes  292  are also rotated so that the direction of the air flow is also controllable.  
         [0133]     In the embodiment illustrated in  FIGS. 19-22 , there are six spokes  284  on the disc portion  282  of the trim flange  256  and six spokes  294  on the rotary disc  258 . However, any number of spokes can be provided.  
         [0134]     In addition, the vent  250  can be used for applications other than venting exhaust air, for example, any application in which control of flow and direction of a fluid is desired including but not limited to air-conditioning and heating applications.  
         [0135]     Referring now to  FIGS. 23 and 24 , another embodiment of a vent in accordance with the invention is designated generally as  310 . Vent  310  includes a mounting flange  312  adapted to engage with the duct  6  and two rotary discs  258  (as described above) attached to the mounting flange  312 . Mounting flange  312  has a generally rectangular shape and includes inner walls  316 , a face plate  318  perpendicular to the inner walls  316  and rim walls  320  extending rearward from the peripheral edges of the face plate  318 . Face plate  318  includes two disc portions  322  each having spokes  324  and openings  326  therebetween. For example, each disc portion  322  may have six spokes  324  and six openings  326  therebetween, although any number of spokes  324  is possible.  
         [0136]     To secure the mounting flange  312  to the duct  6 , screws  328  can be drilled or screwed through the duct into one or more of the inner walls  316  of the mounting flange  312 . Alternatively, the mounting flange  312  can be attached to or engage with the duct  6  in any of the ways described above in connection with the other embodiments of the invention or can be attached to the wall  8  in any of the ways described above in connection with the other embodiments of the invention.  
         [0137]     The rotary discs  258  are attached to the face plate  318  by an appropriate attachment mechanism such as by inserting a screw  330  through aligning apertures in each rotary disc  258  and a respective disc portion  322  of the face plate  318  and threading a nut  332  onto the end of each screw  330  (see  FIG. 24 ). The nuts  332  are fastened but not tightened so that rotation of the rotary discs  258  relative to the disc portions  322  is possible. Alternative attachment mechanism for attaching the rotary discs  258  to the disc portions  322  which enable the rotary discs  258  to rotate relative to the disc portions  322  are also envisioned.  
         [0138]     To install the vent  310 , the rotary discs  258  are attached to the disc portions  322  of the face plate  318 , e.g., by inserting the screws  330  through aligning apertures in the disc portion  290  of the rotary discs  258  and the disc portions  322  of the face plate  318  and threading the nuts  332  onto the end of the screws  330 . Then, the inner walls  316  of the mounting flange  312  are passed through the opening in the wall  8  and into the duct  6  and screws  328  are drilled through the duct  6  into one or more of the inner walls  316 .  
         [0139]     The final step in the installation procedure is to orient the rotary discs  258  to provide the desired flow of air and direction thereof. The rotary discs  258  are independently rotated relative to the face plate  318  of the mounting flange  312  to vary the correspondence between the openings  296  between the spokes  294  of the rotary discs  258  and the openings  326  between the spokes  324  of the disc portions  322  of the face plate  318 . If the openings  296  and  326  are in complete correspondence, a maximum flow of air will be provided by the vent  310  whereas if the openings  296  of the rotary disc  258  align with the spokes  324  of the disc portion  322 , there will not be any flow of air through the vent  310 . Between these two extreme positions, any desired position can be selected.  
         [0140]     Since the rotary discs  258  can be independently rotated, it is possible to have varying degrees of air flow through each rotary disc  258  and provide different flow direction in the same vent  310 .  
         [0141]     When the rotary discs  258  are rotated, the vanes  292  are also rotated so that the direction of the air flow is also controllable.  
         [0142]     The vent  310  can be used for applications other than venting exhaust air, for example, any application in which control of flow and direction of a fluid is desired including but not limited to air-conditioning and heating applications.  
         [0143]     While the invention has been described above with respect to specific apparatus and specific implementations, it should be clear that various modifications and alterations can be made, and various features of one embodiment can be included in other embodiments, within the scope of the present invention. For example, mention is made of the use of the vents described above for adjusting the flow of exhaust air from a dryer. It must be appreciated that this use is an exemplifying use of the invention and does not limit the invention in any manner. The invention is considered applicable for other applications in which it is desired to control a fluid flow such as air.