Vertical discharge roof exhauster

July 24, 1962 lj. jennet al 3,045,579

VERTICAL DISCHARGE ROOF EXHAUSTER

Filed Dec. 7, 1959 ₂ Sheets-Sheet 1

FIB.

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July 24, 1962

L. J. JENN ET AL

3,045,579

FIG.

VERTICAL DISCHARGE ROOF EXHAUSTER

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United States Patent Office

3,045,579

Patented July 24, 1962

045 579

VERTICAL DISCHARGE ROOF EXHAUSTER Louis J. Jenn and John A. Payton, Indianapolis, Ind., assignors to Jenn Air Products Company, Inc., Indianapolis, Ind., a corporation

Filed Dec. 7,1959, Ser. No. 857,782

Claims. (Cl. 98—43)

This invention relates generally to assemblies used as roof-exhausters and in particular to a vertical discharge exhauster assembly which is weatherproof.

Conventional roof exhausters discharge downwardly toward the roof or other surface on which they are installed. While, for some installations, these give satisfactory service, in applications where relatively hot, corrosive, or grease-laden gases are discharged, the downwardly directed gases cause roof deterioration and are a fire hazard. Vertical discharge fans are advantageous for use with domestic or restaurant kitchen canopies in that the odor and grease laden air is directed upwardly for dissipation in the atmosphere rather than directed downwardly to accumulate at lower levels under certain atmospheric conditions. In such applications, accumulations of grease in ducts sometimes catch fire and where downwardly discharging exhausters are used, the flames are driven into the adjacent roof surfaces. When such fires occur where vertical discharge exhausters are used, the flames are directed upwardly and the danger to roofs and other surrounding surfaces is minimized.

Vertical discharge fan or exhauster assemblies are not unknown in the prior art, however, these conventional devices require that the discharged air be directed against a set of louvers which are opened by the air pressure. The problem of weatherproofing these assemblies is obviously present, also the louvers corrode and load with grease making their use with vertical-discharge exhausters, at best, only a partial solution to the problem of weatherproofing a vertical discharge exhauster.

It is the primary object of the present invention to provide a vertical discharge exhauster or fan assembly which is weatherproof and does not require the use of louvers on the discharge side of the assembly.

A further object of the present invention is to provide a vertical discharge fan assembly in which the motor enclosure is removed from the air stream but nevertheless obtains cooling air from outside the fan assembly thereby adapting the assembly for use in discharging corrosive fumes.

A further object of the present invention is to provide an assembly of the type referred to which is formed so that the motor enclosure shields the fan inlet from rain and snow with accumulated moisture being collected in a gutter means and drained away from the assembly.

A further object of the present invention is to provide a vertical discharge fan assembly adapted to be mounted on a roof within the curb area whereby the overall height of the installation is minimized.

The full nature of the invention will be understood from the accompanying drawings and the following description and claims:

FIG. 1 is a side sectional view of an assembly embodying the present invention.

FIG. 2 is a side sectional view similar to FIG. 1 but showing an assembly adapted for use with an axial fan type of impeller.

FIG. 3 is a fragmentary, side sectional view of a modified form of the assembly.

Referring initially to FIG. 1, the fan assembly includes a base frame indicated generally at 10 which overlies and is supported on a curb structure extending upwardly from a roof or other supporting surface. The curb structure borders the mouth of an air passage (not shown) located within the roof or supporting surface structure. The upper end of the frame has a portion 12 extending horizontally inward and normal to the axis of the frame. The inner marginal area of the portion 12 is bent to form an inwardly and upwardly inclined circular flange 13.

A member 14, circular in cross section, overlies the frame 10 and is intermediately bent to provide an inclined flange 16 which overlies the flange 13 and is rigidly secured thereto by means of rivets 17 or similar fastening means. The angle formed in the member 14 at the flange 16 provides a continuous circular gutter 18 and spaced drainage apertures 19 in the member 14 adjacent the gutter provide for drainage thereof.

The portion of member 14 extending below the gutter 18 is bowl-shaped and terminates in a horizontally extending portion 20 having an upturned marginal lip 20 a. The upper marginal area of the member 14 is formed to provide a horizontal flange 21 to which is secured by means of sheet metal screws 22 a horizontally flanged portion 23 of a concave-convex member 24. The members 14 and 24 form a cowl or hood which is of outwardly convex configuration and which is circular in cross section. The upper marginal area of the member 24 is rolled as indicated at 26, the rolled margin of the member 24 defining a discharge aperture.

Mounted at spaced points upon the inner surface of the hood are generally S-shaped resilient elements or spring blades indicated at 27. It will be understood that while the resilient elements 27 are here shown as S-shaped, other configurations might be used, the important functional requirement being that the elements be shaped so that drops of water collecting on the elements will move to a point overlying the gutter 18 before falling from the elements. It will be further understood that the elements 27 might be non-resilient in which case they would act as solid supports not as spring elements. The inner ends of the elements 27 are rigidly secured to the lower member 28 forming a portion of a drive motor enclosure which includes the upper portion 29.

The enclosure formed by the members 28 and 29 is circular in cross section and its configuration is such that its cross sectional diameters at its upper and lower ends are substantially smaller than its intermediate or central cross sectional diameter. The members 28 and 29 are joined by means of sheet metal screws 31, or similar fastening means, and the marginal area of the member 29 is flared outwardly to provide an annular drip ridge 32. The ridge serves to direct rain and condensation, present in the upper area of the assembly, in an outward direction away from the enclosure. The portion of the member 28 adjacent the ridge and indicated at 33 is formed so as to recede from the ridge to prevent the entry, by capillary action, of water into the joint between the members 28 and 29.

A fan motor 34 is mounted within the enclosure by means of bolts 36 and its shaft 37 extends vertically downward from the lower end of the enclosure. Attached to the shaft 37 for rotation thereby is a centrifugal type impeller 38«. The impeller is of conventional form and includes a hub 40 carrying a vane assembly in which the annular member 40« is a structural part. The member 50« is provided with a downwardly bent margin 40b.

Means are provided for circulating air from the exterior of the fan assembly into the motor enclosure to limit the temperature rise of the motor. This means includes a plurality of tubes 41 disposed at spaced intervals between the members 14 and 28. The tubes 41, which may be formed of rigid plastic or aluminum, may have a flanged upper end 42 which seats against a grommet 43 through which the tube extends. The lower end of the tubes 41 extends slidably through a grommet

3,045,579

44. It will be understood that the tubes are slidable within their supporting grommets so that the function of the resilient members 27 in providing a spring suspension mounting for the motor enclosure is not disturbed. As an alternate construction, the tube 41 might be rigidly secured to the members 14 and 23, but formed of a somewhat flexible elastomer so that they may flex upon movement of the enclosure with relation to the hood. It will be understood that, under certain circumstances the resilient elements 27 might be omitted and the tubes 41 themselves used as the supporting means for the motor enclosure. The tubes 41 permit entry of air from the exterior of the assembly into the motor enclosure. Exhaust apertures 46 formed in the member 28 permit air to leave the enclosure, exhaust from the apertures 46 being induced by the flow of air caused by rotation of the impeller.

In operation, with the impeller being driven by the motor 34, air will be drawn upwardly through the frame member and through the space between the hood and the motor enclosure, to be discharged from the top of the hood, as indicated by arrows in FIG. 1. Condensation within the assembly and snow or rain which may enter the assembly through its discharge aperture will impinge upon the enclosure and in running off the enclosure will be directed outwardly by the ridge 32. The water and condensate will be caught in the gutter 18 and drained through the apertures 19 to the exterior of the assembly. Means may be provided, if desired, for carrying off the liquids draining through the apertures 19.

It will be noted that the maximum cross-sectional diameter of the motor enclosure is greater than the diameter of the discharge aperture and also 'greater than the diameter of the aperture bounded by the flange 13. The motor enclosure thus serves to shelter the fan inlet from rain and snow entering the open end of the assembly. It will be understood that while the motor enclosure and cowl are referred to as being circular in cross-section, these elements might also have an outer configuration other than circular or the cowl might extend vertically upwardly from the flange 23, the important functional requirement being that the enclosure have an effective horizontal cross-sectional area which overlaps the area of the inlet aperture bounded by the lip 20α on the member 14 so as to shelter this aperture.

The resilient elements 27 are curved so that liquid dripping from the ridge 32, and intercepted by the resilient elements, will not flow inwardly of the gutter 18 but will move off of the resilient elements and fall to the underlying inclined surface of the member 14. As previously pointed out, the resilient elements might be provided a contour other than S-shaped. The lip 20α on the horizontal portion 20 of member 14 serves as a secondary moisture arresting member by holding any splash over from the gutter 18. It will be noted that the assembly places the motor out of the air stream and yet permits cooling air from outside the assembly to be circulated to the motor, the construction being thereby particularly adapted for use in moving corrosive fumes. The placement of the impeller at least partially within the frame 10 serves to reduce the overall height of the assembly.

Referring now to FIG. 2, there will be described a somewhat modified form of the fan assembly construction, which is adapted to incorporate an axial air movement type of impeller. In FIG. 2, parts which are substantial duplicates of parts found in FIG. 1 are given the same reference numerals as in FIG. 1.

In the structure of FIG. 2, the lower marginal area of member 14 terminates at the gutter flange 160. The annular flange 169 is secured by means of rivets 17 to an adjacent upwardly extending flange or lip 130 formed at the inner marginal edge of the horizontal portion 12 of the frame 10. The lip 130 forms a venturi for the axial type fan assembly which includes the hub 38 carrying blades 39.

The operation of this form of the invention is the same as described with reference to FIG. 1. The tubes 41 provide for the flow of air into the motor enclosure and the motor enclosure is sized so as to shield the aperture defined by lip 130 from moisture entering the upper end of the assembly.

In FIG. 3 a somewhat further modified form of the assembly shown in FIG. 1 is illustrated. The assembly of FIG. 3 differs from that of FIG. 1 in the means for draining moisture from the interior of the cowl formed by members 14 and 24. In FIG. 3 parts which are substantially identical to those of FIG. 1 are given the same reference numerals as in FIG. 1.

Referring to FIG. 3 the member 14 is formed in two parts 14α and 14b. The portion 14α is provided with a flanged lower margin 14c which is joined to the flange 12α on the portion 12 of frame 10 and to the downwardly extending flange 14d at the upper margin of portion 14b by means of bolts 14c. The flanges 14c and 14d are held in spaced relation by means of spacer blocks 15 disposed at intervals between these elements. The arrangement thus provides a circular slot or gap between the parts 14α and 14b which is broken, at intervals, by the blocks 15.

In operation, the moisture which enters the cowl is directed into the space separating the lower cowl portions 14α and 14b and drains therethrough to the exterior of the assembly. It will be evident that the form of the assembly shown in FIG. 3 makes unnecessary the drainage apertures 19 of FIGS. 1 and 2.

While the invention has been disclosed and described in some detail in the drawings and foregoing description, they are to be considered as illustrative and not restrictive in character, as modifications may readily suggest themselves to persons skilled in this art and within the broad scope of the invention, reference being had to the appended claims.