US3412670A

US3412670A - Roof ventilator

Info

Publication number: US3412670A
Application number: US624104A
Authority: US
Inventors: Louis J Jenn; James W Schwier
Original assignee: Jenn Air Corp
Current assignee: Jenn Air Corp
Priority date: 1966-12-20
Filing date: 1966-12-20
Publication date: 1968-11-26
Anticipated expiration: 1985-11-26

Description

Nov. 26, 1968 I J. JENN ETAL 3,412,670

ROOF VENTILATOR Filed Dec. 20, 1966 6 Sheets-Sheet 1 INVENTORS Louis J. Jenn, James W. SG/LWIJer Nov. 26, 1968 L. J. JENN ETAL 3,412,670

ROOF VENTILATOR Filed Dec. 20, 1966 6 Sheets-Sheet 2 INVENTORS Louis J Jenn, (hives M4 Sakwer ATTORNEYS NOV. 26, 1968 JENN ETAL 3,412,670

ROOF VENTILATOR Filed Dec. 20, 1966 6 Sheets-Sheet 5 INVENTORS Lam's d. Jenn, James W So/zwier' ATTORNEYS Nov. 26, 1968 L. J. JENN ETAL ROOF VENTILATOR 6 Sheets-Sheet 4 Filed Dec. 20, 1966 ZNVENTORS Louis J. Jew/z,

James 14/. Sckwz'er W,MM#%% ATTORNEYS Nov. 26, 1968 1.. J. JENN ETAL 3,412,670

ROOF VENTILATOR Filed Dec. 20, 1966 V 6 Sheets-Sheet 5 INVENTORS Louis J Jenn, James 1% Sofia/de ORNEYS NOV. 26, 1968 1 JENN ETAL 3,412,670

ROOF VENTILATOR Filed Dec. 20, 1966 6 Sheets-Sheet 6 United States Patent 3,412,670 ROOF VENTILATOR Louis J. Jenn and James W. Schwier, Indianapolis, Ind., assignors to Jenn-Air Corporation, Indianapolis, Ind., a corporation of Indiana Continuatiou-in-part of application Ser. No. 424,627, Jan. 11, 1965. This application Dec. 20, 1966, Ser. No. 624,104

18 Claims. (Cl. 98-43) ABSTRACT OF THE DISCLOSURE The construction of roof ventilators for exhausting fumes, air, etc. from a building is disclosed, the ventilator embodiments being specifically developed to provide a low height or profile and maximum air flow for the particular ventilator size. A particular relationship for a fan impeller nested in a cavity within the load carrying base member for the ventilator is described where the air drawn through the roof opening is discharged from the impeller upwardly and outwardly or generally obliquely relative to the vertical axis of the ventilator, Embodiments for the ventilator wherein the load carrying and supporting element is an integral curb member or is a formed sheet base member to overlie a preconstructed curb are disclosed.

This application is a continuation-in-part of US. application Ser. No. 424,627 for Unitary Roof Ventilator, filed Jan. 11, 1965, and now abandoned.

This invention relates generally to the art of building ventilation and more particularly to a ventilator to be mounted over a building roof opening to exhaust air, fumes, etc., from the building.

It has generally been characteristic of prior art roof ventilators that they be provided with a support base having a downwardly extending flange which is intended to enclose a rectangular curb specially built up on the building roof to accommodate mounting of the ventilator. This curb is built to surround the roof opening and then the ventilator is mounted to enclose the curb. Prior art ventilators are also commonly provided with a separately mounted backdraft damper positioned in the roof opening beneath the ventilator unit. With this location of the damper, removal of the ventilator unit is required to gain access to the damper for cleaning, adjustment, etc., since usually the damper, mounted in the roof opening, is not accessible from the interior of the building.

A further feature common to existing roof ventilators is the necessity, because of the hereinabove mentioned curb type mounting and usually accepted height requirements for centrifugal fans, that the ventilator be relatively tall so that it towers above the building roof line. This is particularly true of higher capacity ventilators such as are required for large commercial and industrial structures. The height of many available prior art ventilators results in their being objectionable from an architectural standpoint in that by being unreasonably tall and bulky, appearance-wise they do not blend into the building roof line but rather create a cluttered, unsightly appearance for the building roof line.

Recognizing the above-mentioned characteristics common to many prior art roof ventilators, it is a principal "ice object of the present invention to provide an improved roof ventilator which is simple in construction and incorporates a minimum number of components while giving a low profile appearance in its mounted position on a building roof.

It is another important object of the instant invention to provide a ventilator of simple construction which incorporates as an integral part thereof its own supporting curb member such that the ventilator, preassembled as a single unit, is mountable flush on the roof surface without requiring building a separate supporting curb on the roof surface.

Another important object is to provide a ventilator having a formed sheet base member which is to overlie a curb constructed on the building roof and around the roof opening with this load supporting base member carrying thereon the other components of the ventilator including channelized frames which can accommodate dampers and through which frames the air exits from the ventilator.

A further object of the invention is to provide a unitary roof ventilator incorporating in a single assembly a mounting curb, a powered fan and dampers at the fan outlet which are easily accessible for inspection, cleaning and adjustment from the outside of the ventilator without necessitating removal of the ventilator from its permanently mounted position on the building roof.

It is also an object of this invention to provide a unitary roof ventilator constructed of a minimum number of parts wherein the major parts are formed from sheet plastic with metal back-up of the plastic to supply strength for support of the fan motor and impeller in the ventilator, such sheet plastic construction providing protection against rust and corrosion with a variety of different colors being available for the desired ventilator appearance.

It is another object of the instant invention to provide a unitary roof ventilator of minimum height wherein the fan impeller is nested in a cavity in the load carrying member of the ventilator so that the ventilator is provided with a low profile appearance and when mounted on the building roof a clean, uncluttered roof line appearance will result.

A further object is to provide a unitary roof ventilator which is particularly silent in ope-ration by incorporating backdraft dampers at the outlet of the ventilator to be away from the building ceiling area, including an insulated curb that additionally minimizes condensation in the air passages within the ventilator and further providing a ventilator that can easily be employed with a recessed sound attenuating assembly without increasing the ventilator height, this ventilator thus insuring that a minimum of operating noise will be discernible inside the building.

The above and other objects and novel features of the instant invention will be readily apparent from the following description which is given in connection with the accompanying drawings. A number of specific advantages and features present in the ventilator hereinafter described will be pointed out in connection with setting forth the following description of specific embodiments of the invention.

It is to be expressly understood that thedrawings are for the purpose of illustration and are not intended to define the limits of the invention but rather to merely illustrate preferred embodiments incorporating the features of the instant invention. In the accompanying drawings forming a part of this specification and wherein like reference numerals are employed to designate like parts:

FIGURE 1 is a perspective view of the unitary roof ventilator of this invention;

FIGURE 2 is a top plan view of the ventilator;

FIGURE 3 is a side elevational view of the ventilator;

FIGURE 4 is a bottom plan view of the ventilator;

FIGURE 5 is a sectional view taken on line 5-5 of FIGURE 2;

FIGURE 6 is a plan view showing one corner post arrangement incorporated in the roof ventilator;

FIGURE 7 is a side elevational view of the corner post arrangement shown in FIGURE 6;

FIGURE 8 shows an alternative corner post arrangement for the ventilator;

FIGURE 9 is a side elevational view of the modified corner post arrangement of FIGURE 8;

FIGURE 10 is a partial plan view of the ventilator with the cover plate removed and with certain of the parts cut away;

FIGURE 11 is an exploded fragmentary view of one corner post and the associated support bars in the ventilator;

FIGURE 12 is a partial sectional view of a modified H embodiment of the ventilator; and

FIGURE 13 is a sectional view taken on line 1313 of FIGURE 12.

The general overall appearance and arrangement of the components of the roof ventilator of this invention, generally designed by numeral 10, may best be seen in FIGURES 1, 2, 3, and 4, while FIGURES 5 and 12 more clearly indicate in section the interior arrangement of the parts as assembled into the ventilator. FIGURES 1 and 3 clearly illustrate the desired low profile which is achieved in the ventilator construction of this invention.

Referring to FIGURE 5, the unitary roof ventilator 10 is shown in permanent mounted relation to a building roof R, the roof being provided with an air exhaust opening 0 through which the ventilator is designed to draw air, fumes, etc.

The basic load carrying and supporting element of the ventilator 1-0 is provided by a curb member 12 that is an integral part of the ventilator unit. This member is made up from a sheet of plastic material suitably formed into the configuration shown in section in FIGURE 5. An appropriate sheet plastic such as polyvinyl dichloride may be vacuum formed from a single flat sheet into the configuration shown in the drawings to provide the rectangular shell of the curb member. This shell has a peripheral mounting flange 15 which is to rest on the roof surface and which in mounting the ventilator on the roof is permanently or securely fastened to the roof by nails, screws or other fastening means to fix the ventilator in its proper mounted position relative to the opening 0 in roof R. Inwardly of the flange 15 the plastic material is formed on each side of the rectangular curb shell with a canted Wall 16 extending upwardly to a recess 17. Thus, each of the four sides around the exterior of the curb member 12 has a recess 17 extending therealong.

Suitable nailing strips 18 are mounted in the recesses on the four sides of the curb member 12. These nailing strips are provided to facilitate attachment of the flashing F. Thus, as illustrated, the roof flashing material F may be carried all the way up along the four sides of the curb member 12 and nailed to the strips 18 thus insuring against moisture entering around the mounted location of the ventilator. By entirely covering the curb member 12 exterior peripheral wall with the flashing, moisture leakage is prevented even should there be some failure in the material making up the curb member. It

may be noted that with the location of the dampers onthe exhaust side of the ventilator Where they are accessible for adjustment and cleaning without having to remove the ventilator from its mounted position on the roof, it is thereby possible to permanently mount the ventilator on the roof and apply the flashing material in a permanent and water-tight position at the time of original ventilator installation.

The plastic sheet forming the shell of cur-b member 12 extends inwardly and downwardly from the recess 17 to provide the curb member with an upwardly flaring wall 20. This wall terminates at its inner and lower end in a cylindrical section beneath which is a circular throat 21 through which air is withdrawn from the building opening 0.

The formed plastic sheet making up the exterior surface shell of the curb member 12 as described hereinabove has the hollow interior thereof filled with an insulating material 25, such as urethane foam. This filling material offers a dual advantage in not only strengthening and thereby increasing the load carrying capacity for the curb member 12 but also in providing insulation against heat transfer to other components of the ventilator. Thus the insulation of the curb member acts as a deterrent to condensation forming in the air passages of the ventilator during non-use and particularly minimizes condensation inside the fan impeller cavity formed in the upper end of the curb member by the upwardly flaring wall 20. The foamed plastic insulation 25 may be appropriately contoured at 26 to provide a venturi section leading up to the circular throat 21 disposed beneath the fan impeller. This contoured venturi promotes smooth, non-turbulent flow of air into the ventilator.

The upper end of the curb member 12 supports a rectangular frame 30. This frame as shown in FIGURES 5 through 9, is made up of angle members with a vertical leg of each angle extending downwardly between the nailing strip 18 and the outer face of the recess 17 in the curb member. The other leg of each angle extends horizontally outwardly overlying the nailing strip 18. The outer end of this horizontally extending leg has a lip 31 which is turned downwardly at an angle of 45 to conduct moisture away from the ventilator in the event that any should accumulate on or adjacent the upper surface of frame 30.

At each of the four corners of the rectangular frame 30 there is mounted an upstanding corner post 35. These corner posts are suitably mounted on the frame 30 as by welding, and thus project upwardly from the frame 30 and curb member 12 on which the frame is supported. In the corner post embodiment shown in FIGURES 6 and 7 the upper end is provided with two bushings 36. These bushings are provided to receive the hinge pintles which support the backdraft dampers 40. Thus, as shown in FIGURE 5, a damper 40- is pivotally supported at its upper end between adjacent corner posts by a pin 41 which extends into and engages with the bore of the corner post carried bushings 36. A suitable stop 42, which may take the form of a strip of rubber, is mounted along the upper surface of each side of the frame 30 to fix the closed position for the dampers 40.

It will, of course, be appreciated that in the arrangement as shown, four separate dampers 40 are provided,.

one extending along each of the four sides of the rectangular frame 30. Each damper 40 may be formed as shown in section on FIGURE 5 with the strengthening ribs extending longitudinally thereof and the upper end rolled to enclose the hinge pintles 41 which pivotally engage with the corner post bushings 36.

When the ventilator is operating, the dampers 40 will be opened by air flow to positions such as shown in dotted lines on FIGURE 5. When the ventilator is not in operation the dampers will move by gravity to close the ventilator discharge aperture and thus seal the ventilator against entrance of wind, snow, rain and foreign matter. It may be noted that the location of dampers 40 in the discharge aperture of the ventilator also obviates the need for having a separate bird guard with the ventilator. Although as illustrated, the dampers 40 are operable in response to air fiow induced by rotation of impeller 70, it will be understood that the dampers 40 may be mechanically operated by any suitable actuating means.

The top of each corner post 35 has a plug 43 secured therein with an upstanding threaded stud 44 mounted on this plug. Thus, with a corner post at each of the four corners of the rectangular frame 30, the four threaded studs 44 provide a convenient means for mounting and securing the parts of the ventilator that, as hereinafter described, are supported on the corner posts 35.

FIGURES 8 and 9 illustrate a modified form of corner post which may be employed instead of the corner post construction of FIGURES 6 and 7. The frame used with the modified corner post is the same as that shown in FIGURES 6 and 7. The modified corner post 95 is mounted at each of the four corners of frame 30 in upstanding relation to the frame. The upper end of the corner post 95 is formed with notches 96 in place of the bushings 36 as shown in the corner post construction of FIGURES 6 and 7. These notches provide a shoulder on which a separate frame carrying the backdraft dampers may be mounted thereby enabling the dampers and the frame on which they are pivoted to be separated or removed from the ventilator and replaced with ease. The upper end of corner post 95 is closed by a rectangular element 97 secured therein and a threaded stud 98 is mounted on element 97 to function in the manner previously described for threaded stud 44 in the corner post construction.

As best shown in FIGURES 10 and 11, four support bars 45 extend between the upper ends of corner posts 55. Each bar bridges between two adjacent corner posts and is provided at each end with a hole 46 through which the threaded stud 44 on the corner post passes. Further, each bar 45 has a downturned flange 47 along the outwardly facing edge of the bar and where the ends of two support bars overlap the end of One bar is offset as at 48 so that a level flat surface will be presented along the upper face of the support bars. A rubber insulator 49 may be applied over the plug 43 in the upper end of the corner post to lie beneath the overlapping ends of support bars 45 where they rest on the corner post.

The corner posts 35 and support bars 45 mounted thereon carry a separator plate 50 which overlies the curb member 12. This plate preferably consists of a formed sheet plastic element 51 and a metal liner 52. Element 51 may be formed from a single generally rectangular sheet of plastic material as by known vacuum forming tech niques employing a material such as polyvinyl dichloride,

mentioned hereinabove with reference to the material of the shell of curb member 12.

The plate 50 rests on the upper ends of the corner posts 35 with generally rectangular element 51 being provided with suitable apertures to accommodate the upstanding threaded studs 44 on the corner posts 35 while the side edges of the element are supported along their length by support bars 45. The liner 52, as shown more clearly in FIGURE 10, is circular with the outer edge portion of the circular perimeter overlying the midpoints of support bars 45. Thus as explained hereinafter, the weight of components carried by metal liner 52 is transferred to the support bars 45 which in turn transmit this load to the corner posts 35. Inwardly of the perimeters of the element 51 and liner 42, making up the plate 50, there is an annular upstanding ridge 53. This ridge functions, as will be apparent from the description hereinafter, as a barrier against the entrance of moisture into the motor compartment of the ventilator. Inwardly of this annular ridge 53 the plate 50 is formed with a downwardly tapering wall 54 which merges into a horizontal circular center portion 55. The sheet plastic element 51 extends outwardly beyond the annular ridge 53 with a horizontal section 56 which overlies the support bars 45 and this section 56 thereafter terminates in a downwardly turned lip 57.

The liner 52 is constructed to substantially mate with the sheet plastic element 51 in the areas of ridge 53, downwardly tapering walls 54 and center portion 55, and provide the strength and stiffening needed to support the weight of the ventilator motor and fan impeller, transferring the weight of these components through support bars 45 to the corner posts 35. The liner also assists in maintaining the shape of the sheet plastic element 51. The metal liner 52 may be suitably formed to the shape shown in FIGURES 5 and 10 by spinning the sheet metal, such as sheet aluminum, into such shape. In the embodiment as illustrated in FIGURES 5 and 10, the dished center section of liner 52 has a rib 62 spun into the downwardly tapering wall thereof to provide additional strength and also to be available as a support for the components required where the fan impeller is powered through a belt drive such as frequently employed in larger ventilators. In such a construction, the motor mounting plate, fan impeller shaft, etc., can be mounted on brace members that are fastened to rib 62 to transfer the weight thereof to the liner 52.

In the embodiments shown, the separator plate 50 made up of the generally rectangular formed plastic sheet 51 and circular metal liner 52 mounts the drive motor 65 for the ventilator. As illustrated, the motor 65 is secured to the plate 50 by bolts 66 with the shaft 67 of the motor extending vertically downwardly through the plate and into the generally conical fan impeller chamber formed between the downwardly tapering wall 54 of the plate and upwardly flaring wall 20 of curb member 12.

A fan impeller 70 is fixed to the lower end of the shaft 67 of motor 65 to be directly driven by the motor in the embodiment as illustrated. It will be noted that the impeller is nested in the cavity formed by the upwardly flaring wall 20 at the upper end of the curb member 12. This wall and the downwardly tapering wall 54 of the separator plate form a generally conical impeller chamber terminating at its upper and outer end in a circumferential discharge aperture which is closed by the dampers 40 when the ventilator is not operating.

The fan impeller 70 comprises a circular disc 71 which carries a hub 72 at the center thereof, this hub being appropriately secured to the motor shaft 67. The other end of impeller 70 is formed with a generally cylindrical inlet ring 73. This ring, as shown in FIGURE 5, has a radially extending flange at its lower end, such flange being disposed immediately above the throat 21 of the curb member 12 in the mounted position of the impeller. The opposite end of inlet ring 73 has an outwardly fiarin g flange extending generally in the direction of the upwardly flared wall 20 of curb member 12.

The impeller 70 is completely by a series of circumferentially spaced blades 75 which are connected between the disc 71 and the inlet ring 73. Each of these blades is provided with a mounting extension 76 at its upper and lower ends, the extension at one being secured as by rivets 76 to disc 71 and the extension at the opposite end being secured as by rivets t0 the inlet ring 73. The blades 75 extend outwardly and upwardly relative to the peripheries of disc 71 and ring 73 with the blades having curled trailing edges extending up into the generally conical fan impeller chamber formed by the walls 20 and 54. Thus, with the impeller being driven by motor 65, air is drawn through throat 21 into the full open inlet of ring 73 and discharged from blade 75 upwardly and outwardly at an angle to the plane of the impeller toward the circumferential discharge aperture at the upper and outer end of the impeller chamber. This air flow causes the dampers 40 to move to an open position such as that shown in dotted lines on FIGURE 5.

A cover plate 80 is applied over the separator plate 50. This cover plate has appropriately located apertures to receive the four upstanding threaded studs 44 whereupon the support bars 45, plate 50, and cover plate 80 are fixedly secured to the top of the corner posts 35 by 7 means of cap nuts 81. (See FIGURES 2 and 3.) The cover plate may advantageously be formed from a single sheet of plastic, such as polyvinyl dichloride, the forming being carried out by any of the well known vacuum forming techniques used with sheet plastic materials.

The cover plate 80 has a domed central portion 82 surrounded by a horizontal portion 83, this portion ending in downwardly inclined walls 84. From the lower end of the inclined walls 84 the cover plate extends outwardly and downwardly to form a skirt 85 that provides a shield for the backdraft dampers 4-0 against exposure to freezing rain or snow which might interfere with proper opening and closing of these dampers. The skirt 85 on cover plate 80 also acts as a diverter for high winds which, if they were directed against the dampers 40, might cause the damper to stay closed.

As shown more clearly in FIGURES 1, 2, and 3, the inclined walls 84 of the cover plate include a plurality of openings 90. These openings permit air to flow in beneath the cover plate to the compartment containing motor 65 and thereby provide cooling air for the motor during its operation. It will be noted that the upstanding annular ridge 53 formed in the separator plate 50 acts as a barrier to moisture entering the dished cavity of the plate in which motor 65 is mounted. Any moisture that might enter through openings can drain from the ventilator outboard of the dampers 40 by passing across horizontal section 56 and the downwardly turned lip 57 of the sheet plastic element 51.

Another embodiment of a ventilator in accordance with the instant invention identified as 10 is illustrated in the partial sectional view of FIGURE 12. In this embodiment the load carrying and supporting element is provided by a formed sheet base member 112. This load carrying member has a downwardly extending skirt which, when installed, surrounds the preconstructed curb C. The curb C is built in place on the roof surface to surround the roof opening (not shown) and is provided with appropriate wooden members at its upper end on which the load carrying member 112 of the ventilator 10' rests.

Member 112 extends inwardly from skirt 115 providing a flat load carrying wall 116 which merges into an upstanding annular ridge 117. From the annular ridge 117 the member 112 extends inwardly and downwardly to provide an upwardly flaring wall 120. This wall terminates at its inner and lower end in a cylindrical section. At the lower end of this cylindrical section there is a circular throat 121 through which air is drawn from the building opening beneath curb C.

The load carrying member 112 may appropriately be made up from a sheet of plastic material suitably formed into the configuration shown in section on FIGURE 12. An appropriate sheet plastic such as polyvinyl dichloride may be used in forming the member from a single flat sheet. As in the case of member 12 in the previously described embodiment, member 112 will have a generally rectangular overall outline with skirt 115 extending along the four sides of the member.

The upper end of the load carrying member 112 supports on fiat wall 116 a rectangular frame Each side of this frame is made up of an element having a channelized cross section, namely, a central channel 131 with flanges 132 extending outwardly from the end of each flange of the channel. This channelized cross section is shown in section in FIGURE 12. The channels 131 pro ject upwardly from the flat load carrying wall 116 of member 112.

At each of the four corners of the rectangular frame 130 there are mounted upstanding corner posts 135. These corner posts each have a cross section similar to the elements making up frame 130. The corner posts are related to each other as shown in section in FIGURE 13 with the central channel 136 of each corner post projecting or facing away from the corner of member 112. The

corner posts are suitably mounted on the frame 130 as by welding to project upwardly from the frame 130 and load carrying member 112.

The upper portion of the ventilator in the embodiment of FIGURE 12, although not shown, is similar in construction to the upper portion of the ventilator shown in FIGURE 5 except that the support bars 45, such as shown in FIGURES 10 and 11, are replaced with support bars having a cross section like that of the elements making up frame 130 and corner posts 135. The central channel of each of the four support bars extends downwardly, aligned with the

central channels

131 and 136 of the corner post and frame elements with which it is associated. Thus the central channels of the frame 130, corner posts and of the support bars all project inwardly of the opening which they encircle to form a rectangular shoulder facing outwardly of the opening through which the air discharged from the fan impeller passes. With the corner posts at the four corners of load carrying member 112 there are of course four air openings each encircled by such an outwardly facing shoulder. This shoulder, particularly along the portion formed by channels 131, provides a convenient stop against entrance of rain into the ventilator. Also, where the ventilator is provided with dampers mounted on corner posts 135 in a manner similar to that disclosed in the embodiment of FIGURE 5, the rectangular shoulder functions to limit inward movement of the dampers when they are in their closed position.

The elements making up frame 130, corner posts 135 and the support bars in the FIGURE 12 embodiment each may be made from extruded stock material having the cross section shown in section on FIGURES 12 and 13.

Aside from the other components which in the FIG- URE 12 embodiment will be supported on corner posts 135 similar to the components shown in the embodiment of FIGURES l-S, there is shown a portion of a fan impeller on FIGURElZ. This impeller as well as components such as the motor mountings, ventilator cover, etc., are all similar to those shown and described with reference to the FIGURE 1-5 embodiment.

It will be recognized from the description given hereinabove that the ventilator constructions herein described and illustrated in the drawings are of quite simple construction involving only a few parts in the complete assembly. By mere removal of the four cap nuts 81, the cover plate 80 may be lifted ofl? to provide easy access to the drive motor 65 for servicing or replacement. Further, the cover plate with the drive motor and impeller mounted therein may also then be removed as needed to service or clean the fan impeller. With or without removal of the separator plate 50, the mere removal of the cover plate 80 exposes the dampers 40 so as to be easily cleaned and serviced as may be needed.

The construction of the ventilator with the dampers 40 located in the circumferential discharge aperture remote from the building ceiling, the foam filled curb member 12, and the large inlet provided by ring 73 for the impeller, all contribute to quiet ventilator operation. The large full open impeller inlet permits reduced air velocity for a given ventilator capacity thereby contributing to a low operating noise level while the ventilator still delivers maximum air volume.

To further decrease the noise during ventilator operation, a recessed sound attenuating assembly may be mounted beneath the ventilator as by positioning such assembly in the building ceiling structure with the upper level of such assembly disposed generally in the plane of the opening 0 of the roof. The construction of such a sound attenuating assembly may follow the teachings of Jenn et al. Patent 3,110,357.

The low profile or height of the ventilator of this invention is made possible by a number of features of the ventilators construction without loss of air flow capacity. The integral curb member of the ventilator embodiment of FIGURES 1-5 permits flush mounting on the building roof surface. By the load carrying and Supporting element, either curb member 12 shown in section in FIGURE 5 or the formed sheet base member 112 shown in FIGURE 12, having a cavity in its upper end in which the fan impeller is nested, a saving in overall ventilator height is realized. In this connection, the fan impeller design also is important in that it discharges diagonally upwardly out of the cavity in which the impeller is nested. This diagonal air discharge from the impeller contributes to smooth air flow through the ventilator since the air entering the full open inlet ring of the impeller is not required to be diverted directly radially as in the case of conventional centrifugal fan impellers but rather is only propelled diagonally outwardly and upwardly from its original vertically upward path when it enters the impeller inlet ring. Finally, the positioning of the backdraft dampers outboard of the impeller chamber rather than in the common location of beneath the ventilator permits the ventilator to be of low profile or height.

Forming the major parts of the ventilator from sheet plastic material such as polyvinyl dichloride offers a number of advantages. Such construction renders the ventilator free from attack by rust and corrosion. If desired, the fan impeller 70 can be coated with plastic to adapt the entire ventilator for an installation where corrosive fumes are being exhausted. Also, this sheet plastic construction enables a variety of different colors to be provided for the desired appearance of the ventilator in blending in with the building design and construction materials. These, of course, are permanent colors which will not fade, chip, peel or require painting or refinishing.

It is to be understood that the forms of this invention herein shown and described are to be taken only as preferred examples of the invention and that various changes and modifications in the arrangement of parts and interconnection of the components may be resorted to without departing from the spirit of the invention or the scope of the appended claims.

We claim:

1. A unitary ventilator adapted to overlie a building roof opening comprising a curb member having an interior wall defining an upwardly opening circular throat for flow of air therethrough and an exterior peripheral wall to be affixed to the roof area surrounding the root opening, said interior wall including an upwardly flaring wall portion above said throat forming a cavity in the upper end of said curb member with said exterior wall extending downwardly from the upper end of said upwardly flaring Wall portion and spaced outwardly from said interior wall,

a separator plate mounted above said curb member, said separator plate having a downwardly tapering wall spaced above and overlying the upwardly flaring wall portion of said curb member to define therebetween an annular generally conical fan impeller chamber with a circumferential discharge aperture at the upper outer end of said chamber,

a fan impeller rotatably supported in said chamber nested in said cavity, said impeller having blades around the periphery thereof contoured to draw air upwardly through said circular throat and propel it radially outwardly and upwardly through said annular generally conical fan impeller chamber,

power means mounted above said separator plate and connected to drive said fan impeller,

a cover plate overlying said separator plate to define therebetween a compartment for said power means,

said curb member and cover plate being of a formed sheet plastic with said curb member filled with insulating material between said interior and exterior walls, and

said separator plate consisting of a formed sheet plastic element and a metal liner jointly mounting said power means and impeller.

2. A unitary ventilator as recited in claim 1 wherein at least said sheet plastic element has an upstanding annular ridge encircling the upper end of said down-wardly tapering wall, and said cover plate is provided with openings spaced outwardly of said annular ridge to admit cooling air to said compartment.

3. A unitary ventilator adapted to overlie a building roof opening comprising a curb member having an interior wall defining an upwardly opening circular throat for flow of air therethrough and an exterior peripheral wall to be affixed to the root area surrounding the roof opening, said interior wall including an upwardly flaring wall portion above said throat forming a cavity in the upper end of said curb member with said exterior wall extendingdownwardly from the upper end of said upwardly flaring wall portion and spaced outwardly from said interior wall,

upstanding corner posts mounting said separator plate above said curb member, said corner posts being supported on and projecting upwardly from the upper end of said curb member,

a fan impeller rotatably supported in said chamber nested in said cavity, said impeller having blades around the periphery thereof contoured to draw air upwardly through said circular throat and propel it radially outwardly and upwardly through said annular generally conical fan impeller chamfber,

a cover plate overlying said separator plate to define therebetween a compartment for said power means, said cover plate having the periphery thereof extending outwardly and downwardly to form a skirt around the perimeter of said fan impeller chamber, and

air flow actuatable dampers pivotally mounted adjacent the perimeter of said fan impeller chamber between adjacent corner posts.

4. A unitary ventilator adapted to overlie a building roof opening comprising a curb member having an interior wall defining an upwardly opening circular throat for flow of air therethrough and an exterior peripheral wall to be affixed to the roof area surrounding the roof opening, said interior wall including an upwardly flaring wall portion above said throat forming a cavity in the upper end of said curb member with said exterior 'wall extending downwardly from the upper end of said upwardly flaring wall portion and spaced outwardly from said interior Wall,

a separator plate mounted above said cur b member, said separator plate having a downwardly tapering wall spaced above and overlying the upwardly flaring wall portion of said curb member to define therebetween an annular generally conical fan impeller chamber with a circumferential discharge aperture at the upper outer end of said chamber,

a fan impeller rotatably supported in said chamber nested in said cavity, said impeller having blades around the periphery thereof contoured to draw air ing outwardly and downwardly to form a skirt around the perimeter of said fan impeller chamber, said separator plate, said cover plate and said curb member being of formed sheet plastic material, and said separator plate including a dished central portion formed of a metal liner to strengthen the plastic sheet for support of said power means and impeller, said metal liner being circular, and support bars being provided bridging between adjacent corner posts, said support bars passing beneath the peripheral portion of the circular edge of said liner to transfer the weight of said power means and impeller to said corner posts.

5. A unitary ventilator adapted to overlie a building roof opening comprising a curb member formed of sheet plastic and having a circular throat for flow of air therethrough and an exterior peripheral Wall to be afiixed to the roof area surrounding the roof opening, said member having an upwardly flaring wall above said throat forming a cavity in the upper end of said curb member, said member being filled with insulating material,

a rectangular frame carried on the upper end of said curb member, said frame having upstanding posts at the corners thereof,

a separator plate secured to the upper ends of said post-s, said separator plate having a downwardly tapering wall spaced above the upwardly flaring wall of said curb member to define therebetween a generally conical fan impeller chamber with a circumferential discharge aperture at the upper outer end of said chamber, said separator plate consisting of a formed generally rectangular sheet plastic element underlying a generally circular metal liner, said sheet plastic element extending to and being supported on said posts,

support bars supported between adjacent corner posts with the mid-point of each bar passing beneath the edge portion of said liner,

a fan impeller rotatably supported in said chamber nested in said cavity,

power means mounted above said separator plate and connected to drive said fan impeller, said power means and impeller being jointly supported by said sheet plastic element and metal liner, and

a cover plate overlying said separator plate to define therebetween a compartment for said power means, the periphery of said cover plate extending outwardly and downwardly to form a skirt around the perimeter of said fan impeller chamber.

6. A unitary ventilator as recited in claim 5 wherein said insulating material filling said curb member is foamed plastic and the lower portion thereof is formed with a venturi inlet leading to said throat.

7. A unitary ventilator as recited in claim 5 wherein said sheet plastic element has an upstanding annular ridge encircling the upper end of said downwardly tapering wall, and said cover plate is formed of sheet plastic with openings spaced outwardly of said annular ridge to admit cooling air to said compartment.

8. A unitary ventilator as recited in claim 5 wherein dampers are pivotally mounted between said posts to pivot outwardly about horizontal pivot axes.

9. A unitary ventilator as recited in claim 5 wherein said fan impeller comprises a disc provided with a central mounting hub, a cylindrical inlet ring disposed immediately above said throat, and a series of blades circumferentially spaced around said impeller, each blade having extensions at the opposite ends thereof with said extensions being connected to the periphery of said disc and cylindrical inlet ring respectively, said blades having trailing ends projecting outwardly and upwardly Within said generally conical fan impeller chamber.

opening comprising a load carrying and supporting element having an upwardly opening circular throat for flow of air therethrough and an upwardly flaring wall above said throat forming a cavity in the upper end of said element,

upstanding corner posts supported on and projecting upwardly from the upper end of the upwardly flaring wall of said load carrying element,

a separator plate mounted on said corner posts, said separator plate having a downwardly tapering wall spaced above and overlying the upwardly flaring wall of said load carrying element to define therebetween an annular generally conical fan impeller chamber with a circumferential discharge aperture at the upper end of said chamber between adjacent corner posts,

a fan impeller rotatably supported to be nested in the cavity of said load carrying element with a portion of said impeller extending upwardly and outwardly within said annular conical fan impeller chamber, said impeller having blades around the periphery thereof contoured to draw air upwardly through said circular throat and propel it radially outwardly and upwardly through said annular generally conical fan impeller chamber,

a cover plate overlying said separator plate to define the'rebetween a compartment for said power means, said cover plate having the periphery thereof extending outwardly and downwardly to form a skirt around the perimeter of said fan impeller chamber,

said separator plate and said cover plate being of formed sheet plastic material, and said separator plate including a dished central portion formed of a metal liner to strengthen the plastic sheet for support of said power means and said impeller with said metal liner being circular, and

support bars being provided bridging between adjacent corner posts, said support bars passing beneath the peripheral portion of the circular edge of said liner to transfer the weight of said power means and impeller to said corner posts.

11. A roof ventilator adapted to overlie a building roof opening comprising a load carrying and supporting element having an upwardly opening circular throat for flow of air therethrough and an upwardly flaring wall above said throat forming a cavity in the upper end of said element,

said load carrying element being formed with an outer a separator plate mounted on said corner posts, said separator plate having a downwardly tapering wall spaced above and overlying the upwardly flaring wall of said load carrying element to define therebetween an annular generally conical fan impeller chamber with a circumferential discharge aperture at the upper end of said chamber between adjacent corner posts,

power means mounted above said separator plate and connected to drive said fan impeller, and

-a cover plate overlying said separator plate to define therebetween a compartment for said power means, said cover plate having the periphery thereof extending outwardly and downwardly to form a skirt around the perimeter of said fan impeller chamber.

12. A roof ventilator adapted to overlie a building roof opening comprising a load carrying and supporting element having an upwardly opening circular throat for flow of air therethrough and an upwardly flaring wall above said throat forming a cavity in the upper end of said element,

a frame comprised of channelized elements overlying said load carrying element encircling the upper end of said upwardly flaring wall with the channel of each element projecting upwardly, said corner posts extending upwardly from said frame and each of said corner posts being comprised of a channelized element with the channels of the posts at adjacent corners of said frame projecting toward each other and aligned with the upwardly projecting channel of the frame element with which such posts are associated,

a cover plate overlying said separator plate to define therebetween a compartment for said power means, said cover plate having the periphery thereof extending outwardly and downwardly to form a skirt around the perimeter of said fan impeller chamber.

13. A roof ventilator as recited in claim 12 wherein the channels of said channelized elements and of said corner posts provide outwardly facing shoulders, and dampers to close the openings embraced by said shoulders are pivotally mounted between the upper ends of the posts at adjacent corners of said frame.

14. A roof ventilator as recited in claim 12 wherein channelized support bars bridge the upper ends of the corner posts at adjacent corners of said frame with the channel of each bar extending downwardly and aligned with the channels of the frame element and corner posts with which the support bar is associated.

15. A roof ventilator adapted to overlie a building roof opening comprising a load carrying and supporting element having an upwardly opening circular throat for flow of air therethrough and an upwardly flaring wall above said throat forming a cavity in the upper end of said element, said element being formed with an outer downturned skirt encircling the element and a. flat generally horizontal portion intermediate said skirt and said upwardly flaring wall,

upstanding corner posts supported on said flat Wall portion of said load carrying element and projecting upwardly from the upper end of the upwardly flaring wall of said load carrying element,

a frame comprised of channelized elements overlying said load carrying element incircling the upper end of said upwardly flaring wall with the channel of each element projecting upwardly, said corner posts extending upwardly from said frame and each of said corner posts being comprised of a channelized element with the channels of the posts at adjacent corners of said frame projecting toward each other and aligned with the upwardly projecting channel of the frame element with which such posts are associated,

a separator plate mounted on said cover posts, said separator plate having a downwardly tapering wall spaced above and overlying the upwardly flaring wall of said load carrying element to define therebetween an annular generally conical fan impeller chamber with a circumferential discharge aperture at the upper outer end of said chamber between adjacent corner posts,

a fan impeller rotatably supported to 'be nested in the cavity of said load carrying element, said impeller having blades around the periphery thereof contoured to draw air upwardly through said circular throat and propel it radially outwardly and upwardly through said annular generally conical fan impeller chamber,

impeller drive means mounted upon said separator plate and connected to drive said fan impeller, and

a cover plate overlying said separator plate to define therebetween a compartment for said impeller drive means.

16. A roof ventilator as recited in claim 15 wherein the channels of said channelized elements and of said corner posts provide outwardly facing shoulders, and dampers to close the openings embraced by said shoulders are pivotally mounted between the upper ends of the posts at adjacent corners of said frame.

17. In a roof ventilator having a load carrying and supporting element with an upwardly opening circular throat for flow of air therethrough and mounting means disposed above said load carrying element, said mounting means supporting a fan impeller disposed above said load carrying element and drive means connected to drive said fan impeller, the improvement comprising a frame of channelized elements overlying said load carrying element with the channel of each channelized element projecting upwardly,

corner posts comprised of a channelized element extending upwardly from said frame with the channels of the posts at adjacent corners of said frame projecting toward each other and aligned with the upwardly projecting channel of the frame element with which such posts are associated, and

channelized support bars bridging the upper ends of the corner posts at adjacent corners of said frame with the channel of each bar extending downwardly 15 and aligned with the channels of the frame element and corner posts with which the support bar is associated, said mounting means being carried by said support bars and corner posts.

18. In a roof ventilator as recited in claim 17 Wherein the improvement further comprises the channels of said channelized elements and of said support bars provided outwardly facing shoulders, and

dampers to close the openings embraced by said shoulders are pivotally mounted between, the upper ends at the posts at adjacent corners of said frame.

References Cited UNITED STATES PATENTS Solzman 98-43 Jenn 98-116 Gohl 98-43 Jenn 98-116 Rudy 98-43 Cook 98-43 10 ROBERT A. OLEARY, Primary Examiner.

M. A. ANTONAKAS, Assistant Examiner.