Silencer for a roof exhaust

Abstract

A silencer for a roof exhaust has a duct defining an inlet fluidly connected with the axial fan and an outlet for discharging air from the duct. The duct has peripheral walls forming an exterior of the duct, including: a bottom wall, a top wall, and first and second side walls spaced from each other and extending from the bottom wall to the top wall. A plurality of bent sheet metal wall sections fastened to each other form the bottom wall, the top wall and the first and second side walls, including first, second and third wall sections having first, second and third profiles that are shaped differently. Baffles are connected to the peripheral walls and define a passageway that fluidly connects the inlet to the outlet. An acoustic material for acoustically isolating the duct is disposed between the baffles and the peripheral walls.

What is claimed is: 
     
         1 . A silencer for a roof exhaust, comprising:
 a duct defining an inlet configured to be fluidly connected with the roof exhaust and an outlet for discharging air from the duct, the duct comprising a plurality of peripheral walls that together form an exterior of the duct,   the plurality of peripheral walls comprising:
 a bottom wall; 
 a top wall opposite the bottom wall; and 
 first and second side walls spaced from each other and extending from the bottom wall to the top wall, 
   the duct comprising a plurality of bent sheet metal wall sections fastened to each other to form the bottom wall, the top wall and the first and second side walls,   the plurality of bent sheet metal wall sections including:
 a plurality of first wall sections, each first wall section of the plurality of first wall sections having a first profile; 
 a plurality of second wall sections, each second wall section of the plurality of second wall sections having a second profile; 
 a plurality of third wall sections, each third wall section of the plurality of third wall sections having a third profile, 
 the first, second and third profiles being shaped differently; 
   a plurality of baffles connected to the peripheral walls, the baffles defining a passageway of the silencer that fluidly connects the inlet to the outlet; and   an acoustic material for acoustically isolating the duct, at least part of the acoustic material being disposed between the baffles and the peripheral walls.   
     
     
         2 . The silencer of  claim 1 , wherein:
 the duct has a duct height measured between the bottom wall and the top wall; and   in a cross-section of the silencer taken along a plane that is normal to the bottom wall, top wall and side walls and spaced from the inlet, the duct is symmetric about an axis bisecting the duct height.   
     
     
         3 . The silencer of  claim 1 , wherein:
 the duct has a duct width measured between the first and second side walls; and   in a cross-section of the silencer taken along a plane that is normal to the bottom wall, top wall and side walls and spaced from the inlet, the duct is symmetric about an axis bisecting the duct width.   
     
     
         4 . The silencer of  claim 1 , wherein, in a cross-section of the silencer taken along a plane that is normal to the bottom wall, top wall and side walls and spaced from the inlet, each of the first and second side walls is formed by two of the first wall sections fastened to each other. 
     
     
         5 . The silencer of  claim 4 , wherein each first wall section of the plurality of first wall sections comprises:
 a first portion extending vertically along approximately half of a duct height measured between the bottom wall and the top wall, the first portion having a first end and a second end;   a second portion extending horizontally and laterally inwardly from the first end;   a third portion extending horizontally and laterally inwardly from the second end; and   a fourth portion extending vertically from the second portion to form a U shape together with the first and second portions.   
     
     
         6 . The silencer of  claim 5 , wherein the second portion is longer than the third portion. 
     
     
         7 . The silencer of  claim 5  or  6 , wherein, in the cross-section of the silencer taken along the plane, each of the first and second side walls is formed by the two of the first wall sections connected to each other by the third portions thereof. 
     
     
         8 . The silencer of any one of  claims 5  to  7 , wherein each first wall section of the plurality of first wall sections further comprises a fifth portion extending horizontally and laterally inwardly from the fourth portion. 
     
     
         9 . The silencer of any one of  claims 5  to  8 , wherein each first wall section of the plurality of first wall sections further comprises a sixth portion extending vertically from the third portion to form a U shape together with the first and third portions. 
     
     
         10 . The silencer of any one of  claims 5  to  9 , wherein, in the cross-section of the silencer taken along the plane, each of the bottom wall and the top wall is formed by a pair of the first wall sections, a pair of the second wall sections and one of the third wall sections. 
     
     
         11 . The silencer of  claim 10 , wherein, in the cross-section of the silencer taken along the plane, each of the bottom wall and the top wall is formed at least in part by the second portion of each first wall section of the pair of the first wall sections. 
     
     
         12 . The silencer of  claim 10  or  11 , wherein, in the cross-section of the silencer taken along the plane, in each of the bottom wall and the top wall:
 the one of the third wall sections is disposed centrally and between the pair of the second wall sections; and 
 the pair of the second wall sections is disposed between the pair of the first wall sections. 
 
     
     
         13 . The silencer of any one of  claims 10  to  12 , wherein:
 each second wall section of the plurality of second wall sections is generally C-shaped; 
 each second wall section of the plurality of second wall sections has a central portion and two end portions extending from opposite ends of the central portion; and 
 in the cross-section of the silencer taken along the plane, for each of the bottom wall and the top wall, the central portion of each second wall section is vertically aligned with the second portion of each first wall section. 
 
     
     
         14 . The silencer of  claim 13 , wherein:
 each second wall section of the plurality of second wall sections has two lip portions extending from respective ones of the end portions; and   for each second wall section of the plurality of second wall sections, the lip portions are generally perpendicular to the end portions and extend toward a centerline of the second wall section bisecting a distance between the end portions.   
     
     
         15 . The silencer of  claim 13  or  14 , wherein:
 each third wall section of the plurality of third wall sections is generally step shaped; and 
 each third wall section of the plurality of third wall sections has a central elevated portion and two end portions extending from opposite ends of the central elevated portion; and 
 in the cross-section of the silencer taken along the plane, for each of the bottom wall and the top wall, the central elevated portion of the one of the third wall sections is vertically aligned with: (i) the central portion of each second wall section, and (ii) the second portion of each first wall section. 
 
     
     
         16 . The silencer of  claim 15 , wherein:
 each third wall section of the plurality of third wall sections has two lip portions extending from respective ones of the end portions of the third wall section; and   for each third wall section of the plurality of third wall sections, the lip portions are generally perpendicular to the end portions of the third wall section and extend away from a centerline of the third wall section bisecting a distance between the end portions of the third wall section.   
     
     
         17 . The silencer of any one of  claims 1  to  16 , wherein each baffle of the plurality of baffles is perforated. 
     
     
         18 . The silencer of any one of  claims 1  to  17 , wherein:
 each baffle of the plurality of baffles comprises a plurality of baffle panels that are fastened to each other; and 
 each baffle panel of the plurality of baffle panels is a piece of bent sheet metal. 
 
     
     
         19 . The silencer of  claim 1 , wherein the plurality of baffles comprises:
 a first side baffle connected to the first side wall, a first part of the acoustic material being disposed between the first side baffle and the first side wall;   a second side baffle connected to the second side wall, a second part of the acoustic material being disposed between the second side baffle and the second side wall;   at least one top baffle connected to the top wall, a third part of the acoustic material being disposed between the at least one top baffle and the top wall; and   at least one bottom baffle connected to the bottom wall, a fourth path of the acoustic material being disposed between the at least one bottom baffle and the bottom wall.   
     
     
         20 . The silencer of  claim 19 , further comprising a deflector pod extending between the bottom wall and the top wall, the deflector pod comprising:
 a third side baffle of the plurality of baffles connected to the bottom wall and the top wall, a first sub-passage being defined between the first side baffle and the third side baffle; and   a fourth side baffle of the plurality of baffles connected to the bottom wall and the top wall, a second sub-passage between the second side baffle and the fourth side baffle,   a fifth part of the acoustic material being disposed between the third side baffle and fourth side baffle of the deflector pod.   
     
     
         21 . The silencer of  claim 20 , wherein:
 in a cross-section of the silencer taken along a plane that is normal to the bottom wall, top wall and side walls and traversing the deflector pod, each of the bottom wall and the top wall is formed by a pair of the first wall sections, a pair of the second wall sections and one of the third wall sections;   each third wall section of the plurality of third wall sections is generally step shaped;   each third wall section of the plurality of third wall sections has a central elevated portion and two end portions extending from opposite ends of the central elevated portion;   the third side baffle is fastened to a first end portion of the two end portions; and   the fourth side baffle is fastened to a second end portion of the two end portions.   
     
     
         22 . The silencer of any one of  claims 1  to  21 , further comprising a fiber glass membrane disposed between the baffles and the acoustic material. 
     
     
         23 . The silencer of any one of  claims 1  to  22 , further comprising a plurality of adjustable legs connected to the duct, a height of each adjustable leg of the plurality of adjustable legs being adjustable to selectively set a distance between the bottom wall and a roof on which the roof exhaust is mounted. 
     
     
         24 . The silencer of  claim 1 , wherein:
 in a cross-section of the silencer taken along a plane that is normal to the bottom wall, top wall and side walls and spaced from the inlet, each of the bottom wall and the top wall is formed by a pair of the first wall sections, a pair of the second wall sections and one of the third wall sections;   in each of the bottom wall and the top wall:
 the third wall section is disposed centrally and between the pair of the second wall sections; and 
 the pair of the second wall sections is disposed between, the pair of the first wall sections; 
   each first wall section of the plurality of first wall sections comprises:
 a first portion extending vertically along approximately half of a duct height measured between the bottom wall and the top wall, the first portion having a first end and a second end; 
 a second portion extending horizontally and laterally inwardly from the first end, the second portion forming in part an exterior surface of a corresponding one of the bottom wall and the top wall; 
 a third portion extending horizontally and laterally inwardly from the second end; 
 a fourth portion extending vertically from the second portion to form a U shape together with the first and second portions; and 
 a fifth portion extending horizontally and laterally inwardly from the fourth portion; 
   each second wall section of the plurality of second wall sections is generally C-shaped and comprises:
 a central portion; 
 two first end portions extending from opposite ends of the central portion; and 
 two first lip portions extending from respective ones of the first end portions, the first lip portions being generally perpendicular to the first end portions and extending toward a centerline of the second wall section bisecting a distance between the first end portions; 
   each third wall section of the plurality of third wall sections is generally step shaped and comprises:
 a central elevated portion; 
 two second end portions extending from opposite ends of the central elevated portion; 
 two second lip portions extending from respective ones of the second end portions, the second lip portions being generally perpendicular to the second end portions and extending away from a centerline of the third wall section bisecting a distance between the second end portions; 
   in the cross-section of the silencer taken along the plane, in each of the bottom wall and the top wall:
 a laterally outermost one of the first lip portions of each of the second wall sections is disposed above or under the fifth portion of an adjacent one of the first wall sections; 
 a laterally innermost one of the first lip portion of each of the second wall sections is disposed above or under a corresponding one of the second lip portions of the one of the third wall sections. 
   
     
     
         25 . The silencer of  claim 1 , wherein:
 in a cross-section of the silencer taken along a plane that is normal to the bottom wall, top wall and side walls and spaced from the inlet:
 each of the first and second side walls is formed by two of the first wall sections; 
 each of the bottom wall and the top wall is formed by a pair of the first wall sections, a pair of the second wall sections and one of the third wall sections; 
   the plurality of baffles comprises:
 a first side baffle connected to the first side wall, a first part of the acoustic material being disposed between the first side baffle and the first side wall; 
 a second side baffle connected to the second side wall, a second part of the acoustic material being disposed between the second side baffle and the second side wall; 
 at least one top baffle connected to the top wall, a third part of the acoustic material being disposed between the at least one top baffle and the top wall; and 
 at least one bottom baffle connected to the bottom wall, a fourth path of the acoustic material being disposed between the at least one bottom baffle and the bottom wall; 
   the silencer further comprises a deflector pod extending between the bottom wall and the top wall, the deflector pod comprising:
 a third side baffle of the plurality of baffles connected to the bottom wall and the top wall, a first sub-passage being defined between the first side baffle and the third side baffle; 
 a fourth side baffle of the plurality of baffles connected to the bottom wall and the top wall, a second sub-passage between the second side baffle and the fourth side baffle, 
 a fifth part of the acoustic material being disposed between the third side baffle and fourth side baffle of the deflector pod. 
   
     
     
         26 . The silencer of  claim 1 , wherein:
 the duct has a first end and a second end;   the bottom wall, the top wall and the first and second side walls extend from the first end to the second end;   the inlet is defined by the bottom wall;   the plurality of peripheral walls further comprises a first end wall closing off the first end of the duct; and   the outlet is defined at the second end of the duct.   
     
     
         27 . The silencer of  claim 26 , further comprising a deflector pod disposed laterally between the first and second side walls, the deflector pod defining in part first and second sub-passages between the deflector pod and the first and second side walls respectively,
 the deflector pod being spaced from the first end of the duct,   the inlet being disposed between the first end of the duct and an end of the deflector pod.   
     
     
         28 . A silencer for a roof exhaust, comprising:
 a duct defining an inlet configured to be fluidly connected with the roof exhaust and an outlet for discharging air from the duct, the duct comprising a plurality of peripheral walls that together form an exterior of the duct,   the plurality of peripheral walls comprising:
 a bottom wall defining the inlet; 
 a top wall opposite the bottom wall; 
 first and second side walls spaced from each other and extending from the bottom wall to the top wall, 
 the bottom wall, the top wall and the first and second side walls extending from a first end of the duct to a second end of the duct; and 
 a first end wall defining the first end of the duct, 
   a plurality of baffles connected to the peripheral walls, the baffles defining a passageway of the silencer that fluidly connects the inlet to the outlet; and   an acoustic material for acoustically isolating the duct, at least part of the acoustic material being disposed between the baffles and the peripheral walls.   
     
     
         29 . An exhaust assembly comprising:
 a roof exhaust configured to be mounted to a roof, the roof exhaust comprising a conduit for discharging air therefrom, the conduit defining a central axis; and   the silencer of  claim 28  mounted to the roof exhaust,   wherein the central axis extends through the bottom wall of the duct.   
     
     
         30 . A method for installing a silencer, comprising:
 connecting a first silencer module to a roof exhaust, the first silencer module defining an inlet of the silencer configured to be in fluid communication with the roof exhaust, the first silencer module forming an acoustic plenum for attenuating sound; and   connecting a second silencer module to the first silencer module such that the first silencer module and the second silencer module form a continuous duct, the second silencer module defining an outlet of the silencer, the second silencer comprising an acoustic splitter defining two passages such that the acoustic splitter diverts air flow received by the second silencer module into the passages.   
     
     
         31 . A silencer for a roof exhaust, comprising:
 a duct defining an inlet configured to be fluidly connected with the roof exhaust, and an outlet for discharging air from the duct, the duct comprising a plurality of peripheral walls that together form an exterior of the duct;   a first silencer module defining a first part of the duct including the inlet, the first silencer module being configured to be connected to the roof exhaust, the first silencer module forming an acoustic plenum for attenuating sound; and   a second silencer module defining a second part of the duct including the outlet, the second silencer module being fastened to the first silencer module, the second silencer comprising an acoustic splitter defining two passages such that the acoustic splitter diverts air flow received by the second silencer module into the passages.