US3454128A - Acoustical attenuators - Google Patents

Description

sheet of 5 July 8, 1969 w. N. NoPPER ACOUSTICAL ATTENUATORS Filed June' 10, 1966 INVNTOR.

ATTORNEY W/LLARD N. NOPPER EJE l wie 6 l 2 La. 2 2 d 3.

July 8, 1969 y Filed June 10, 1966 EEE W. N. NOPPER ACOUSTICAL ATTENUATORS Sheet v9 of 5 31E: BY

INVENTOR.

Wl ARD N. NOPPER ATTORNEY July 8, 1969 w. N. NoPPER y 3,454,128

Y ACOUSTICAL ATTENUATORS Filed June l0, 1966 Sheet Of' 5 www..- rf

"LA-Sz@ INVENTOR 29 WIL D N. NOPPER ATTORNEY July s, 1969 w. N. NOPPER 3,454,128

ACOUSTICAL ATTENUATORS Filed June 1o, 196e sheet 5 of 5 INVENTOR Wl/ LARD N. NOPPER BWM ATTORNEY United States Patent O 3,454,128 ACOUSTICAL ATTENUATORS Willard N. Nopper, Berea, Ohio, assignor to Loren 'Cook Company, a corporation of Ohio Filed June 10, 1966, Ser. No. 556,601 Int. Cl. F01n 1/24 U.S. Cl. 181-50 13 Claims ABSTRACT F THE DISCLOSURE An acoust-ical attenuator including a housing having oppositely disposed side and end walls, with side and end panels in the interior of the housing adjacent the side and end walls, respectively, and a plurality of elongated sound attenuating elements connecting the side panels together. The length of the elongated elements is less than the interior spacing between the side walls to permit insertion of the side walls and elongated elements into the housing as a unit. The housing also has top and bottom walls with openings therethrough, and one of the top and bottom walls has portions extending inwardly of the end panels, with the outermost elongated elements being in line with the inner edges of lthe inwardly extending portions.

My invention relates to an attenuator, the lower portion of which is shaped to be supported on a curb and the upper portion of which is shaped to support a ventilator, which attenuator has means associated therewith for attenuating sound waves arising from sources outside of the building to which the ventilator is applied and particularly to sound waves initiated by the motor and fan or blower of the ventilator. It also relates to sound attenuating apparatus which is removably inserted in curbs and to the combination of a curb and such apparatus which combination may be considered an attenuator.

In buildings, such as hospitals, libraries, churches, and auditoriums, it is found desirable to attenuate sound waves passing through the usual ventilator from outside sources and particularly noise which is initiated by the motor and the fan or blower when power-operated means is energ-ized to expel contaminated air from a room or building on Which the ventilator is installed. In accordance with my invention, I have provided an attenuator for application to a curb of the usual type which is designed to support a ventilator or I may provide apparatus which may be inserted into and removed from a curb having means associated therewith for attenuating sound waves arising from sources outside of the building and particularly sound waves passing from the motor and fan or blower when a power-operated ventilator supported upon the curb is utilized -to expel contaminated air from a room or buildmg.

In accordance with my invention, I have provided an attenuator having an upper portion which is shaped to support a ventilator which attenuator includes a metal housing containing side, end, and bottom panels or slabs formed of a compressed acoustical material, such as libre glass, and a plurali-ty of elongated acoustical elements, such as rods or tubes, formed of a similar material which are supported by the side slabs and are arranged in staggered relation to each other so that sound waves passing through or initiated by the motor and fan or blower of the ventilator must follow a circuitous path during their passage to a room or building on each the ventilator is installed. When my improved attenuator is arranged between a curb and a ventilator, it may be readily removed from the curb to provide access to the louvers and duct work. It is also within the scope of my invention to provide an attenuator which may be incorporated in ICC and sold in combination with or separately from a curb and which may be easily removed from the curb for nspection or repairs. When applied to a curb, compressed attenuating material may also be provided including elongated acoustical elements which are so arranged that they obstruct a direct line of sight from the inlet opening to the outlet opening of the curb and so tha-t sound waves passing through the curb must iiow in a circuitous path through the curb.

My invention will be better understood by reference to the accompanying drawings in which:

FIG. l is a perspective view of one form of my improved attenuator showing it arranged above a curb 0f the usual construction;

FIG. 2 is an exploded view of my improved attenuator showing the parts prior to assembly;

FIG. 3 is a cross sectional view of one form of my improved attenuator showing it applied to a curb which is also shown in cross section;

FIG. 4 is a cross sectional view taken on a plane passing through the line 4-4 of FIG. 3 with parts of the tubes shown broken away and in section;

FIG. 5 is a cross sectional view of the attenuator shown in FIG. l;

FIGS. 6, 7, and 8 are cross sectional views of other modifications of my improved attenuator, FIG. 6 showing parts of a ventilator in cross section lsupported by the attenuator;

FIG. 9 is a cross sectional view of a curb showing another form of my attenuator having the lower portion of a ventilator mounted thereon;

FIG. 10 is a cross sect-ional view similar to that shown in FIG. 9 but showing a larger number of acoustical tubes;

FIG. 1l is a cross sectional view taken on a plane passing through the line 11-11 of FIG. 10; and

FIG. 12 is a plan view of the attenuator shown in FIG. 10 when removed from the curb.

As illustrated in the drawings, my improved attenuator which is designated generally by the numeral 1 in FIG. l is shown arranged above a curb designated generally by the numeral 2 upon which the attenuator is shaped to be supported as illustrated in FIG. 3. As shown in FIGS. l to 8, my improved attenuator includes an outer housing 3, -side panels or slabs 4 and 4a and 5 and 5a, end panels or slabs 6 and 6a and 7 and 7a, and bottom panels or slabs 8 and 8a.

In assembling the acoustical material in place, side panels are provided, each of which consists of a pair of slabs 4 and 4a and 5 and 5a as shown in FIG. 2 and in a like manner two end slabs 6 and 6a are provided which are arranged oppo-sitely to end slabs 7 and 7a. The slabs are arranged interiorly of the sides and ends of the housing 3 and are formed of an acoustical material which also has thermal insulating properties, such as fibre glass. While the double slabs 4 and 4a, 5 and 5a, 6 and 6a, 7 and 7a, and 8 and 8a, may be formed integral with each other, it has been found that a better compression of the slabs may be eiected when their thickness is limited. The slabs are preferably formed under a pressure of approximately four to ten pounds per square inch. In preparing the attenuatng material, aligned apertures are formed in the oppositely disposed slabs 4 and 4a and 5 and 5a and the opposite ends of elongated acoustical material, such as round rods or tubes, are mounted in the aligned apertures or openings. The tubes or rods are arranged to eliminate a staight line of sight from the ventilator through the attenuator.

The number of tubes provided in each attenuator will of course depend upon the size of the attenuator. When the attenuator is small two rods or tubes may be provided as shown in FIG. 5. Generally, however, at least three tubes or rods are provided as shown in FIGS. 3 and 4 and at least five tubes or rods are preferably provided as shown in FIG. 6. Although either tubes or rods may be provided to connect the oppositely disposed side slabs together, tubes are preferably utilized because they have less weight and require less material than rods and tests show that their sound attenuating properties are just as good as rods. It will of course be understood that when the term elongated acoustical elements is specified in the claims, it will include either rods or tubes as well as elongated acoustical material of other shapes.

When the attenuator is in its upright position as shown in FIG. 3 but prior to the bending of the side walls of the housing to form the top wall and the downwardly extending upper flanges, the side acoustical panels with the elongated acoustical connecting elements, such as tubes or rods in place, are inserted in the housing of the attenuator. The end panels are then inserted in the housing after which the top portions of the side and end walls are bent inwardly and downwardly to form the top wall 9 and the downwardly extending flanges 10 and the mitered corners of the side and end walls of the attenuator are welded together. As clearly shown in FIG. 4, the side panels extend the full width of the side walls, and the end panels extend between the side panels. The housing is then inverted as shown in FIG. 2 and the bottom panels or slabs 8 and 8a which are secured to a retaining or bottom wall by suitable means, such as glue, are xed in place to provide the bottom wall. The retaining wall is preferably formed of four parts 11, 12, 13 and 14 which are welded together and include four flanges 15, 16, 17 and 18, respectively.

After the side panels, together with their elongated acoustical elements and the end panels are assembled in place in the housing and the top por-tion of the side and end walls of the housing have been bent over the slabs and their mitered corners welded together, the housing is inverted and the retaining wall, together with :the slabs 8 and `8a are inserted in place and the outer ends of the segments of the retaining wall are welded to the walls 3 of the housing.

The elongated acoustical elements which are designated by the numeral will 0f course vary in number depending upon the size of the attenuator but must be sufficient in number to obstruct a straight line path between said elongated elements and also a direct line of vision between the opening formed by the downwardly extending flanges 10 of the upper wall portions and the opening formed by the upwardly extending flanges 15, 16, 17 and 18 formed on the bottom retaining wall. As shown in FIGS. 3 and 8 of the drawing, the bottom or retaining wall and bottom panels extend inwardly of the side and end panels and vertical lines passing through the flanges and 18, respectively, of `the bottom wall are tangent to the outermost elongated acoustical elements.

In my improved attenuator, a gasket 20 formed of a resilient material, such as neoprene, is provided upon which rests the foundation of a conduit means upon which the ventilator 20a is supported as shown more particularly in FIG. 6 and the side walls of the housing of the attenuator are provided with outwardly extending flanges 21 to enable the attenuator to be easily fitted on the curb 2.

The curb 2 may be of any desired form, such as shown in application Ser. Nos. 310,818 filed on Sept. 23, 1963 and 410,522 filed on Nov. 12, 1964, in the name of Loren Cook, both of `which are assigned to the Loren Cook Company. A perspective view of a desirable curb is shown in FIG. 1 and a cross sectional view is shown in FIG. 3. As shown, the curb has side walls 22, each of which is provided with a cant 23 which terminates in a horizontal wall 24. The side walls 22 are also bent inwardly to provide a top wall 25 which terminates in .4 downwardly extending flanges which are mitered and welded together to hold side and end slabs 27 and 28 which are formed of an acoustical and thermal insulating material, such as libre glass, in place. The curb is also provided with a bottom wall 29 which terminates in upwardly extending flanges which holds the lower end p0rtions of the slabs 27 and 28 in place.

FIGS. 7 and 8 are similar to the structures shown in FIGS. 1 to 5 and are prepared in the same manner. In FIG. 7, seven acoustical tubes 19 and in FIG. 8 eleven acoustical tubes 19 are shown.

In accordance with my invention instead of providing an attenuator supported between the curb and the ventilator, the sound attenuator may be arranged within the curb and the curb may be of a form somewhat resembling the attenuator shown in FIG. 8 and for the purpose of the present invention may be considered an attenuator. This form of my invention is shown in FIGS. 9 to 12, inclusive. The curbs shown in FIGS. 9 and l0 are substantially the same as the attenuator shown in FIGS. 1 to 8 with the exception that the side and end walls are provided with outwardly extending cants 23 which terminate in horizontal walls 24 which curbs are similar to the curb shown in FIG. 1 and the retaining wall is provided with upwardly extending flanges 15, 16, 17 and 18 which are similar to the flanges shown in FIG. 5 and have consequently been designated by the same reference numerals. In FIG. 9, however, the bottom retaining wall extends outwardly in mating engagement with the wall 24. As shown, the outwardly extending flanges 15, 16, 17 and 18 define the lbottom opening. Apertures may of course be provided in walls 24 and 29 to enable the curb to `be secured to a roof, or they may be secured to a roof by other means, such as welding.

As shown in FIGS. 9 to 12, the supports for the elongated acoustical material consists of longitudinally extending metal straps 30` and 31 which are supported by a series of vertically extending straps 32 and 33 as `shown in FIG. 9 or 32, 33 and 34 as shown in FIG. 10, the upper portion of which straps terminate in flanges 35 and 36 as shown in FIG. 9 or flanges 35, 36 and 37 as shown in FIG. 12 which rest upon one side wall of the curb as shown in FIG. 11. Similar longitudinally eX- tending straps which are supported by vertically extending straps 32a and 33a, or 32a, 33a and 34a as shown in FIG. 12 are arranged on the opposite side of the curb which are supported by - flanges 35a and 36a, or 35a, 36a and 37a as shown in FIG. 12.

The acoustical and thermal insulating material may be in the form of tubes as shown in prior structures and may be supported by studs welded to the straps on the opposite sides of the curbs. Preferably, however, metal tulbes are provided upon which the acoustical tubes are mounted and the opposite ends of the metal tubes are welded or otherwise secured to the straps on the opposite sides of the curb. A resilient material 38, such as sponge rubber, may be superposed over the curb upon which the ventilator 20a rests as shown in FIG. 9 which also absorbs sound. A similar resilient material which has been designated by the same reference numeral may be superposed over the top wall of the curb shown in FIG. 3.

In the form of the invention sho-wn in FIGS. 9 to l2, the removable sound attenuating material, including the straps and tubes, may be sold separately and introduced into curbs of various types. It may also be removed for inspection and repairs. Preferably, however, it is sold in combination with the curb shown in which it is inserted in place in such a manner that the outer sides of the outer tubes 19 are tangent respectively to a line drawn through the flanges 15 and 17 of the retaining Wall.

What is claimed is:

1. A sound attenuator including a housing having an inlet opening and an outlet opening, a plurality of elongated elements formed of a material having sound attenuating properties, and means for supporting said elongated elements within the housing in a position to obstruct a straight line view from the inlet opening to the outlet opening of the attenuator, said last-mentioned means comprising a plurality of longitudinally extending straps supported by vertical straps which vertical straps have flanges resting upon the upper wall of the attenuator.

2. A sound attenuator as defined in claim 1 in which the elongated acoustical material is in the form of tubes and include an elongated metal member extending through each of the tubes, the opposite ends of which are supported by the straps arranged on the opposite sides ofthe attenuator.

3. A sound attenuator comprising a housing having oppositely disposed side and end walls, side 4and end panels of sound attenuating material slidably received within said housing adjacent each of said side and end walls, respectively, and .a plurality of elongated elements connecting said side panels together, the length of said elongated elements being slightly less than the interior spacing between said side walls to permit insertion of said side walls and elongated elements into said housing as a unit.

4. A sound attenuator as detined in claim 3 wherein the opposite ends of said elongated elements are closely received in openings in said side panels.

5. A sound attenuator as defined in claim 3 wherein said side panels extend the full width of said side walls, and said end panels extend between said side panels.

`6. A sound attenuator as defined in claim 3 wherein said elongated elements are of sound attenuating material and are in staggered relation to each other to obstruct a straight line path between said elongated elements.

7. A sound attenuator as defined in claim 6 wherein said elongated elements are round.

8. A sound attenuator as defined in claim 6 wherein said housing has a top wall and bottom wall connected to the upper and lower edges of said side and end walls, and openings extending through said top and bottom walls, one of said top and lbottom walls having a portion extending inwardly of said end panels in said housing,

the outermost of said elongated elements being in line with the inner edge of said inwardly extending portion.

9. A sound attenuator as defined in claim 3 wherein each of said side and end panels comprises a pair of slabs overlying one another.

10. A sound attenuator as defined in claim 3 wherein the top edge of said side and end walls is bent over one edge of said side and end panels to provide a top wall with a central opening through said top wall.

11. A sound attenuator as defined in claim 10 further comprising a bottom wall secured to the lower portion of said side and end walls, and bottom panels secured to said bottom wall, said bottom wall and bottom panels extending inwardly of said side and end panels.

12. A sound attenuator comprising a housing having oppositely disposed side and end walls, and top and bottom walls having openings therethrough, panels within said housing adjacent said side and end walls, one of said top and bottom walls having portions extending inwardly of said panels from opposite walls, and a plurality of elongated sound attenuating elements supported within the interior of said housing, said elongated elements being in staggered relation to each other to obstruct a straight line path between said elongated elements, the outermost ones of said elongated elements being in line with the inner edge of the inwardly extending portions.

13. A sound attenuator as defined in claim 12 wherein said elongated elements are round, and the outermost ones of said elongated elements are tangent to a line passing through the inner edge of the inwardly extending portions.

References Cited UNITED STATES PATENTS 1,865,677 7/ 1932 Cheyney. 2,112,608 3/1938 Schmidt. 2,847,729 8/ 1958 Zingone. 2,959,243 1l/1960 Smith 18156 XR 3,219,143 ll/1965 Bohanon 181-56 XR 3,330,379 7/1967 `Cook 181-50 3,347,338 10/1967 Childress a 181--56 FOREIGN PATENTS 638,407 6/ 1950 Great Britain.

ROBERT S. WARD, IR., Primary Examiner.

U.S. Cl. X.R. 98-43; 181--56

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