US3748997A

US3748997A - Acoustical insulated fan and temperature conditioning penthouse unit

Info

Publication number: US3748997A
Application number: US00241567A
Authority: US
Inventors: F Dean; J Reese
Original assignee: TEMPMASTER CORP
Current assignee: TEMPMASTER CORP
Priority date: 1972-04-06
Filing date: 1972-04-06
Publication date: 1973-07-31
Anticipated expiration: 1990-07-31
Also published as: CA998340A; GB1403278A; CH559313A5; CA974889A

Abstract

A penthouse type air conditioning unit has an acoustically insulated fan which separates the fan motor from the fan discharge end portion by compartments within the unit. Each compartment is acoustically insulated with the discharge compartment being interconnectable with the conventional air conditioning ductwork. The fan impeller is mounted for exposed rotation without the use of the usual enclosure directional scroll and creates the pressure differential for conditioned air flow through the interconnected air ductwork. A target sound attenuator is mounted in the motor compartment at a preselected distance from the fan inlet to attenuate the predominant sound wave frequency generated by the fan. A second embodiment separates the fan motor and the fan impeller by an acoustical compartment which encloses the impeller and interconnects with air conditioning ductwork. A target sound attenuator is supported a preselected distance away from the fan inlet, said distance corresponding to the predominant sound wave frequency generated by the fan.

Description

United States Patent 1191 Dean, Jr. et al.

[ July 31, 1973 [75] Inventors: Frank JJDean, Jr., Kansas City, Mo.;

James A. Reese, Overland Park,

Kans.

[73] Assignee: Tempmaster Corporation, Kansas City, Mo.

22 Filed: Apr. 6, 1972 21 Appl. No.1 241,567

Primary Examiner-William J. Wye Attorney-William B. Kircher [5 7 ABSTRACT A penthouse type air conditioning unit has an acoustically insulated fan which separates the fan motor from the fan discharge end portion by compartments within the unit. Each compartment is acoustically insulated with the discharge compartment being interconnectable with the conventional air conditioning ductwork. The fan impeller is mounted for exposed rotation without the use of the usual enclosure directional scroll and f 98/40 z 6 creates the pressure differential for conditioned air' Int Cl F24 13/00 flow through the interconnected air ductwork. A target Sound attenuator is mounted in the motor compaw [58] of Search 3 51 ment at a preselected distance from the fan inlet to at- 1 l tenuate the predominant sound wave frequency gener- [56] References Cited ated by the UNITED STATES PATENTS A second embodiment separates the fan motor and the fan impeller by an acoustical compartment which encloses the impeller and interconnects with air 2'112'221 3/1938 841221111131 1: 62/262 cnditining ductwmk' A target smmd attenuam is 2:2l4:467 9/1940 Lambert 62/262 preselected away fmm 2,730,873 1/1956 Harden 62/262 Inlet sald (stance correspondmg the predomlmmt 2,920,460 1/1960 Atchison..... 62/296 sound wave frequency generated y the 2,989,855 6/1961 Thompson 62/296 3,112,623 12/1963 Crossman 62/296 13 Clam, 9 Drawmg XX t\ 6 A 1* I g b C :5 1 x 1 ours/05 A; A/R 32 b 22 /i 7. H 2 4 Q If f l A T I I; Z0 7 t f, /7 V \I i l 1 w L4 lc l/ l I /a 50 1 l Q i /9 f &=/ w /6 97/59 v9 /2 l ,l l

/ l* i A fiiTl/R/V 701/? t PAIENIEU JUL 3 I ma SHEET 1 0F 3 PAIENIED JUL3 1 ms SHEET 2 0F 3 PAIENIED JUL 3 I I975 3.748.997 sum .3 OF 3 ACOUSTICAL INSULATED FAN AND TEMPERATURE CONDITIONING PENTHOUSE UNIT BACKGROUND AND BRIEF DESCRIPTION OF THE INVENTION Penthouse type air conditioning and heating units generally operate to supply conditioned air for the main ductwork of large and small buildings of all types. The associated air conditioning or heating system will generally include terminal units or air diffusers in particular room areas within the building structure and,.

since the penthouse unit will include a large fan often generating objectionable noise, sound attenuating devices are normally in the air convergance systems located adjacent to the fan unit or throughout the system in conjunction with the terminal unit and/or air diffusers. These sound attenuating devices installed in the air conveyance system are both expensive to construct and are time and labor consumingin their installation.

The subject invention pertainsto unique acoustically treated penthouse type air conditioning units and to acoustically insulated fan units which may be separable from the penthouse. The penthouse air conditioning units will include an acoustically insulated structure that will have one end portion interconnectable with the return air conveyance system of a building structure and will have mounted therein filtering, air conditioning or heating coils which will condition the return air as it is pulled therethrough by the fan unit located within the penthouse structure. Immediately adjacent the. air conditioning or heating coils will be a space within the penthouse unit that is accessible from the exterior and which has the fan unit motor and target sound attenuator located therein and mounted on a resilient spring support. The motor drive shaft is belt connected with the horizontal fan drive shaft, the latter extending through an acoustically insulated wall and into an acoustically insulated compartment with air discharge outlets. A compressible material acts as a compression seal between the discharge outlet compartment acoustical insulated wall and the intermediate motor compartment. In this manner, the fan impeller is completely located within the discharge outlet compartment while the motor driving same is acoustically insulated therefrom and located in the intermediate area. The fan impeller has the usual scroll eliminated therefrom which would normally provide a directional component to the air flow generated therefrom. One or more suitable outlet connecting means are provided to enable the air conditioning or heating ductwork to attach directly to the discharge outlet compartment.

Further sound attenuation is provided by locating target sound attenuator a preselected distance away from the fan inlet. This distance is a function of the quarter wave length of the predominant noise frequency, which in most cases is related to the blade frequency of the sound produced by the fan.

The second embodiment of the invention includes an acoustical insulated fan unit which will include the outlet or discharge compartments substantially enclosing the fan impeller with the normal fan scroll removed and with the target sound attenuator spaced the required distance away from the fan inlet and with the motor lo-' cated exterior of the outlet or discharge compartment.

An object of our invention is to provide a substantially improved penthouse air conditioning or fan unit which has improved sound level characteristics with little or no reduction in capacity or efficiency in the normal operative ranges.

Another object of our invention is to provide an improved penthouse air conditioning unit that is uniquely constructed and which substantially reduces the normal installation cost either in new or existing building structures.

Further object of the invention is to provide uniquely constructed air conditioning or heating penthouse and- /or fan unit which eliminates upstream and downstream sound attenuating devices normally required. It is a feature of this invention that the unit will operate to provide a unique source of sound attenuated air for the temperature conditioning of large or small buildings and operates in conjunction with both the supply and return air conveyance systems.

Still further object of the invention is to provide a penthouse air conditioning unit of the character described which is economically and acoustically practical to locate same on top of new or existing buildings and which eliminates further use of upstream or downstream noise attenuating devices heretofore required by units of a similar size.

A further object of the invention is to provide a penthouse air conditioning unit having a uniquely constructed and positioned target sound attenuator. It is a feature of this attenuator that it is spaced a preselected distance from said fan structure and is related with the quarter wave length of the predominant sound fre quency to thereby attenuate objectionable noise levels normally associated with large fan units.

A further object of the invention is to provide a uniquely constructed penthouse air conditioning fan unit which both acoustically attenuates objectionable noise levels produced by the fan located therein but at the same time provides an easily accessible repair and service area for the entire unit.

Another object of the invention is to provide a uniquely constructed air conditioning penthouse unit and/or fan unit which has eliminated the normal directional scroll from the centrifugal fan impeller. Accordingly, the above structure enables an acoustically insulated outlet compartment (having a plurality of outlets) to be utilized with the interconnection with normal ductwork optionally located at any position or several places with respect to said compartment.

Another object is to provide essentially uniform air velocity leaving the unit discharge so that downstream duct performance at fittings and takeoffs in close proximity will provide predictable results.

Still further object of the invention is to provide a unique structure for acoustically insulating and separating the fan impeller and the fan motor from the enclosure. It is a feature of the object that the fan is mounted on a resilient structure and further permits and compensates for the pressure differential between the fan inlet and outlet or discharge compartment.

Other and further objects of the invention, together with the features of novelty appurtenant thereto, will appear in the course of the following description.

DETAILED DESCRIPTION OF THE INVENTION FIG. I is a side view of the penthouse air conditioning unit with portions thereof broken away to indicate the general construction of the unit including the, inlet, the air conditioning coils, the intermediate or access section which is occupied by the fan motor and the target sound attenuator, the acoustical wall and structure separating the intermediate section from the outlet section and the fans impeller, the solid line arrows indicating the normal air flow while the broken line arrows indicate the sound travel pattern;

FIG. 2 is a rear elevational view of the target sound attenuator, the fan motor, the resilient fan mount andthe portion of the wall separating the fan motor section from the outlet section;

FIG. 3 is a sectional view taken generally along the line 3-3 of FIG. 1 in the direction of the arrows and showing the inlet to the fan;

FIG. 4 is an end elevational view taken from the outlet or discharge end portion of the fan;

FIG. 5 is a side elevational view of a fan unit utilizing the target sound attenuator with two fan impellers located within the acoustically insulated outlet or discharge section and with the solid line arrows indicating the air flow;

FIG. 6 is a view similar to FIG. 5 but with a single inlet, target sound attenuator and fan impeller located within the acoustically insulated outlet or discharge compartment and with the solid line arrows indicating the air flow to and out of the fan unit;

FIG. 7 is an enlarged sectional view taken generally along the line 7-7 of FIG. 1 in the direction of the arrows and showing the construction of the acoustically insulated wall separating the outlet compartment from the intermediate compartment;

FIG. 8 is a view similar to FIG. 7 but showing the upper wall opening construction and is an enlarged view of the same elements shown in FIG. 1; and

FIG. 9 is a view similar to FIG. 8 but showing the lower separating wall construction.

Turning now more particularly to the drawings, reference numeral 10 generally represents the completely enclosed box-like penthouse unit which will be constructed of sound attenuating material such as glass fiber matting enclosed steel siding. The housing 10 will have an inlet 11 which is provided with a grillwork l2 and which is interconnectable with the return air ductwork of a building heating or air conditioning system. The initial air flow, as indicated by the solid arrows, is through the inlet end and air conditioning coils generally indicated by the numeral 14. It should be pointed out that these air conditioning coils may be arranged vertically or on the incline and may take on various forms such as filters and/or heating or air conditioning coils and the showing in FIG. 1 is merely representative of any one or all of the above.

Numeral 14 represents the intermediate section which is accessible through an access door (not shown) and which will enclose the fan motor and target sound attenuator described infra. In any event, the intermediate section will be terminated in the left to right direction by sound insulating wall generally indicated by the numeral 15. As will be seen, this insulating wall 15 has a large opening defined therein which assists in the flexible mounting of the fan unit and motor/target support.

The fan, which will be described in more detail later, is mounted on a framework generally indicated by the numeral 16. For example, FIGS. 1 and 2 indicate the angle structurals which form a portion of framework 16 and which support fan motor 17 thereon. The exact shape and structural form of the framework may be varied; however, it is contemplated that the structurals 16a may be mounted to extend through the opening of the wall 15 and will further have the cross structural 16b weldedly connected thereto for reinforcing purposes. Located near the forward portion of wall 15 upright structurals 16c extend vertically upwardly and terminate in the horizontal shaft supporting structurals 16b which spans the two upright members.

In a similar manner, the discharge outlet compartment 18 has a transverse structural 16b interconnected between the longer structural 16a discussed above. Likewise, uprights 16c vertically locate the horizontal cross shaft supporting structural 16d at the proper location within the outlet or discharge compartment 18. In both situations, the framework 16 is supported on heavy duty compression springs which are indicated by the numeral 19. As will be seen, the compression vibration isolators 19 support the entire fan assembly including the later described target sound attenuator.

A pair of upright angle structurals, identified by the numeral 20 in FIGS. 1 and 2, is supported by the framework 16 within the intermediate compartment area 14 before acoustically insulated wall 15. Brackets 20a extend horizontally therefore and operate to hold a target sound attenuator 21 a pre-selected distance away from the fan input (extremity of 27) as will be described in more detail.

The fan is generally represented by the numeral 22 and is supported with its axis lying in a substantially horizontal plane by the

upright structurals

16c and 16c as mentioned above. Further, the upright structurals 16c and are spanned by the fan

shaft supporting structurals

16d and 16d respectively. A suitable bearing mount 23 will be located on the inlet side of wall 15 and is bolted or otherwise fixedly attached to the structural 16d. A similar bearing mount 24 is located on the outlet side of wall 15 within the outlet compartment 18 and in the same horizontal plane as hearing mount 23. The rotatable fan shaft 25 extends through the two bearing mounts with the inlet end of the shaft having the belt pulley 26 fixedly located thereon. Motor 17 through belt 17a drives pulley 26 and rotates shaft 25 for appropriate fan action.

In the disclosed embodiment, the fan inlet is represented by the numeral 27 and is frustoconically shaped to channel the air flow (as shown by the solid arrows) into contact with the rotating impeller 28. The impeller operates in a centrifugal fashion to impart a velocity to the air flow which will change to a pressure differential under the influence of outlet compartment 18. It should be pointed out that the location of ductwork 29 and the outlet 18a within compartment 18 is entirely variable and can be made dependent solely upon the structural requirements of the particular building being temperature conditioned. Also, with the acoustically insulated compartment 18 and the later described isolating structure for the fan impeller 28, no scrolls or other air flow directional means which would normally circumscribe wheel 28 are needed.

Turning now once again to FIG. 1, it was mentioned above that the communicating opening in wall 15 (between compartments 14 and 18) was substantially rectangular and centrally located. As shown in FIGS. 1 and 3, wall 15 both structurally and acoustically separates the intermediate compartment 14 from the outlet compartment 18 save for the location of the fan inlet 27 in the rectangular opening. This rectangular opening (in wall 15) is further occupied by the structure, now to be described, which gives some degree of flexibility to the enclosure and around the fan inlet 27 in the remainder of the wall 15.

The FIGS. I and 79 detail the general construction of the remainder of the wall enclosure. For example, each vertical side of the rectangular (or other suitable shape) opening in wall 15 has an angled structural 30 extending substantially the length thereof. A similarly shaped (in section) angular structural 31 is offset toward the compartment 18 and is substantially parallel to each structural 30. The structurals 31 include a sheet metal backing 32 with a circular opening (or aperture) cut therein to be engaged over the frustoconical inlet 27 of the fan 22. Finally, a compressible rubber (or other suitable material) strip 33 occupies the space between flanges 30a and 31a of the

structurals

30 and 31 respectively. This compressible rubber strip 33 permits the two above-described structures to move towards each other as the pressure or force within outlet compartment l8 begins to build up during operation of the fan. The upper portion of the sheet metal strip 32 has structural 34 attached to and extending along the horizontal edged portion thereof. The corresponding or mating horizontal edge of the opening in wall 15 supports structural 35 with the downtumed flange 35a permitting the rubber strip 36 to be located between same and the upturned flange portion 34a of the structural 34. Finally, FIG. 1 discloses the lowermost interconnecting section which will include the lower structural 37 being fixedly attached to the floor of penthouse and having the upturned flange 37a extending vertically up and into the rectangular opening space. The lower edge portion of the circularly apertured sheet metal strip 32 has structural 38 weldedly connected thereto with the downtumed flange 38a forming an overlapping relationship with the upturned flange 370. This permits the location of the compressible rubber stripping 39 to be located therebetween to completely enclose the rectangularly opening with a resiliently mounted centrally apertured sheet metal structure that, under the forces acquired within compartment 18, is permitted fore and aft movement with respect to wall 15. In this manner the differential pressure acting on plate 32 and fan inlet 22 compresses the rubber strip and makes the seal.

The penthouse air conditioning unit described above has an internal air flow substantially as shown by the solid arrows in FIG. 1. In other words, the air flow is through the inlet 11, past the air conditioning coils l3, and in through the fan inlet 27. The fan impeller 28 accordingly creates a sufficient pressure differential within the compartment 18 that the air flow is through outlet 18a down through the building system ductwork 29.

With the airflow pattern described above, should be pointed out that arrows shown in broken lines represent the sound level path that is created by the various rotating and motor elements. But for the penthouse being constructed of sound-deadening acoustically insulating material, the sound level would be transmitted both through the return air and the downstream ductwork. However, even further sound attenuating benefits are obtained by the utilization of the target sound attenuator 21. As suggested above, this attenuator (which may assume various shapes and sizes) is supported by the upright brackets 20 a preselected distance away from the end extremity of the inlet 27 of fan 22. This preselected distance is based on the predominant noise frequency produced by the fan. It has been further found that the third octave band is generally (for centrifugal fans) the predominant noise frequency. For example, when the frequency is found to be in the order of 200 cycles per second, a five foot wave length may be ascribed to such an octave band. By locating the target sound attenuator a quarter wave length away (or approximately 14 inches for a 5 foot wave length) the maximum fan noise attenuation is obtained that would otherwise very likely tend to be transmitted in terms of an objectionable decibel level into the return air ductwork. This target sound attenuator has further enabled the subject acoustically insulated penthouse air conditioning unit to eliminate the use of downstream or return air sound attenuating devices throughout the entire system.

Alternative embodiments are shown in FIGS. 5 and 6. This structure pertains to an acoustically insulated fan unit which may or may not be utilized with-the penthouse construction described above. It is contemplated that a similar type of framework will support the fan unit and said framework is generally represented by the numeral 40. Spring mounts 40a support the framework 40 and provide for the mounting of motor 17 in the manner described above. The motor shaft 25 extends into and through an acoustically insulated sound deadening box generally indicated by the numeral 41. As shown in FIG. 5, a pair of target sound attenuators 21a and 21b are mounted with respect to the inlets of the sound deadening box 41. These inlets,hereinafter identified by the numerals 41a and 41b, are immediately adjacent and in communicating relationship with the inlets of two fan impellers 28a and 28b respectively, same being rotated by the single shaft 25. The box outlet 410 permits the usual interconnection with the outlet ductwork for the building heating or air conditioning system. It is contemplated that an alternative ar-I rangement may include two motors 17 with each motor arranged to rotate a separate shaft 25. However, in ei ther case both target sound attenuators would be utilized at a preselected distance corresponding to the predominant sound frequency way from the inlets to the sound deadening box 41.

The embodiment shown in FIG. 6 is again similar to that shown in FIG. 5, however, a single fan is utilized with inlet 41a with respect to the sound deadening box 41. It should be pointed out that in both cases the airflow into inlets 41a (or the combined inlets 41a and 41b) may be through suitable filtering, heating coils and/or air conditioning coils and will be in and around the motor and target sound attenuators until transmitted through the outlet and into the ductwork. However, this structure results in a significant lowering of the sound to a suitable level obviating the utilization of a downstream or return air sound attenuator as heretofore required by such units.

Both the penthouse construction, as well as the sound deadening boxes, have been found to reduce the typical noise levels in air conditioning and heating systems by 10 to 20 decibels (db). This is a substantial noise reduction made possible by the overall construction of the unit. Further, this modular type construction permits substantial prefabrication and requires only that hookup be accomplished directly on the building top or at other prescribed locations, depending upon the available and desired duct facilities.

From the foregoing, it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the structure.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Having thus described our invention, we claim:

1. An air conditioning penthouse, said penthouse forming a substantially enclosed structure having side walls and a top cover, said penthouse comprising an inlet, said inlet being connectable with return or outside air conveyance system,

at least one outlet, said outlet being connectable with conditioned air conveyance system,

a fan means, said fan means having an impeller of the centrifugal type without a scroll surrounding same and a motor means, said motor means operable to drive said impeller, and

an acoustical insulating wall, said insulating wall acoustically separating said motor means from said impeller, said impeller located in communicating relationship with said outlet and operable to create conditioned air flow out of said penthouse through said outlet, said acoustically insulating wall substantially attenuating objectionable noise produced by said motor means and precluding same from accompanying said air flow through said outlet.

2. A combination as in claim 1 including a target sound attenuator, means for mounting said target sound attenuator within said penthouse on said motor side of said acoustical insulating wall a preselected distance away from said fan.

3. A combination as in claim 2 including means mounted within said penthouse on said motor side of said acoustical wall for conditioning air flow entering said penthouse through said inlet.

4. A combination as in claim 2 including means for acoustically insulating said side walls and said top cover of said penthouse.

5. A combination as in claim 4 including means mounted within said penthouse on said motor side of said acoustical wall for conditioning air flow entering said penthouse through said inlet.

6. A combination as in claim 2 wherein said acoustical insulating wall has an aperture defined therein, said fan having an inlet structure interconnecting with said impeller, and means for resiliently mounting said inlet structure in communicating relationship with said aperture in said acoustically insulating wall.

7. A combination as in claim 6 including means mounted within said penthouse on said motor side of said acoustical wall on conditioning return air flow entering said penthouse through said inlet.

8. A combination as in claim 7 including means for acoustically insulating said side walls and said top cover of said penthouse.

9. A combination as in claim 6 wherein said penthouse has an acoustically insulated floor structure interconnected with said side walls, meansfor resiliently mounting said motor and said impeller on said floor.

10. The combination as in claim 1 including means at least partially enclosing said impeller for producing a uniform velocity profile for the airleaving through said outlet.

11. A self contained fan unit, said fan unit comprising an acoustically insulated structure, said structure having an inlet and an outlet,

a fan means, said fan means having an impeller of the centrifugal type without a scroll surrounding same and a motor means, said motor means operable to drive said impeller, means for mounting said impeller within said acoustically insulated structure, means for mounting said motor exterior of said acoustically insulated structure, said fan unit thereby operable to acoustically attenuate noise produced by said impeller and to create an air flow out said outlet being substantially free of objectionable impeller noise.

12. A combination as in claim 10 an inlet target sound attenuator, means for mounting said target sound attenuator exteriorally of said structure a preselected distance away from said fan.

13. The combination as in claim 11 wherein said structure includes a means at least partially enclosing said impeller for producing a uniform velocity profile for the air leaving through said outlet.

Claims

1. An air conditioning penthouse, said penthouse forming a substantially enclosed structure having side walls and a top cover, said penthouse comprising an inlet, said inlet being connectable with return or outside air conveyance system, at least one outlet, said outlet being connectable with conditioned air conveyance system, a fan means, said fan means having an impeller of the centrifugal type without a scroll surrounding same and a motor means, said motor means operable to drive said impeller, and an acousticAl insulating wall, said insulating wall acoustically separating said motor means from said impeller, said impeller located in communicating relationship with said outlet and operable to create conditioned air flow out of said penthouse through said outlet, said acoustically insulating wall substantially attenuating objectionable noise produced by said motor means and precluding same from accompanying said air flow through said outlet.

9. A combination as in claim 6 wherein said penthouse has an acoustically insulated floor structure interconnected with said side walls, means for resiliently mounting said motor and said impeller on said floor.

10. The combination as in claim 1 including means at least partially enclosing said impeller for producing a uniform velocity profile for the air leaving through said outlet.

11. A self contained fan unit, said fan unit comprising an acoustically insulated structure, said structure having an inlet and an outlet, a fan means, said fan means having an impeller of the centrifugal type without a scroll surrounding same and a motor means, said motor means operable to drive said impeller, means for mounting said impeller within said acoustically insulated structure, means for mounting said motor exterior of said acoustically insulated structure, said fan unit thereby operable to acoustically attenuate noise produced by said impeller and to create an air flow out said outlet being substantially free of objectionable impeller noise.