US3542373A - Space heating apparatus - Google Patents

Description

United States Patent [54] SPACE HEATING APPARATUS 9 Claims, 3 Drawing Figs.

[52] U.S. Cl. 263/19, 126/1 10 [51 1 int. Cl F231 9/04 [50] Field ofSearch 263/19;

[56] References Cited UNITED STATES PATENTS 8/1953 Heiman 126/110 3,270,738 9/1966 Nielsen 126/110 FUREIGN PATENTS 219,136 12/1958 Australia 126/110 717,859 2/1942 Germany 126/110 Primary Examiner- Edward G. Favors Attorney-Harness, Dickey & Pierce ABSTRACT: Apparatus for heating the space within a building consists of a sheet metal cabinet supported by the roof and projecting downwardly through an opening in the roof as well as upwardly above the roof and defining a hooded inlet for fresh air. The unit contains a burner above the roof, a centrifugal fan on a vertical axis below the roof and depending frorr the ceiling into the building. Fresh air is drawn from above the roof into the top of the cabinet, downwardly through a burnel contained therein and laterally in all directions within the in terior of the building space.

Patented Nov. 24, 197% 3,542,373

Sheet 2 012 l SPACE HEATING APPARATUS BACKGROUND OF THE INVENTION So-c'alled makeup air heaters of a direct fired type in common use consist ofa cabinet adapted to be mounted outside a building, frequently upon the roof, and containing an open flame gas burner and a centrifugal fan, fresh air being drawn through the burner and projected into the building. In addition to the cabinet structure required in such assemblies as presently in general use, it'has also been considered necessary to enclose the centrifugal fan in ahousing of the scroll type, and to provide within the building deflecting means for distributing the outlet air in desired directions and to eliminate the direct blast from the fan which would otherwise conccn Irate the output in a single direction. The present invention improves upon the aforementioned common type of roofmounted makeup airheater in several respects, while at the same time provides a'more compact, more attractive, quieter construction and one which is less costly both to manufacture and to install. The invention requires no special fan casing, no special air distributing means, and distributes the output throughout 360.

The objects ofthe invention may be summarized as directed to the improvement of such heaters in the indicated respects, and further objects and advantages will become apparent upon consideration of the present disclosure in its entirety.

BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWING FIG. I is a vertical cross-sectional-view of a heater constructed in accordance with the present invention, showing the same installed in a roof which is fragmentarily diagrammatically illustrated;

FIG. 2 is a horizontal sectional plan view taken substantially on the line 11-" of FIG. I, looking in the direction of the arrows; and

FIG. 3 is a vertical section taken substantially on the line III-III of FIG. I and looking in the direction of the arrows.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, reference character designates generally a roof structure the-details of which may vary and in themselves form no part of my present invention, but which is provided with a rectangular opening 12 and suitable flashing 14, which provides a weather seal to a stepped or Z-section metallic supporting frame 15 extending around the opening 12, mounted on supporting curbing 16 which extends around the opening. Frame 15 is contoured to provide a horizontal supporting shelf flange 18 near or somewhat below the roof top plane and upon which rests the cabinet structure generally designated 20. The rectangular Sheet metal cabinet structure extends upwardly above the roof and carries at its top a sheet metal weather hood 22 which extends outwardly on all sides around the vertical cabinet walls and has turneddown weather protective sides defining inlet openings 24 on all four sides through which air enters in an upward direction. The vertical walls open into the hood so that the air must flow inwardly and turn 180 to then flow downwardly through the cabinet and through the framed opening into the building. Filters 25 of conventional or any suitable type are provided in the openings 24, removably mounted in channel frames 26 so that they may be installed, removed and serviced through the openings 24.

The cabinet also supports, in a position projecting upwardly into the hood 22 an open-flame-type gas burner 30, although other sources of heat may of course be used. The entrance to the cabinet may be somewhat restricted, depending upon the desired type and capacity ofthe heat source, by a top panel 32 containing an inlet opening 33 proportioned to the particular burner which the designer may install, as desired capacity and other engineering considerations may dictate.

A fan support'fr grg egstructure is secured to the main frame 18 and depends info -th building space, consisting of vertical framing members 35 attached at their upper ends to frame I8 and carrying at their lower ends transverse horizontal framing members 36 and a bottom closure panel 44. The cabinet structure 20 also carries in a position spaced above the roof line horizontal cross frame members 38. The vertical depending framing members 35 are positioned to surround and support a circular fan area within which a centrifugal fan impeller 40 is mounted to rotate on a vertical axis in bearings 41, 42 carried by cross members 3o, 38. Panel 44 blocks the lower side ofthe impeller and prevents direct downflow of incoming air. The cagelike enclosure defined by vertical frame members 35, etc. around the fan is open except at its upper portion which is shrouded for an axial distance down from the top equivalent to about 46 percent of the axial length of the fan rotor by a concentric cylindrical radially outspaced sheet metal shroud 45.

The downflowing air is guided into the axial entrance at the upper end of the impeller by a suitable inlet cone 46, which, in cooperation with'shroud 45 prevents direct reentry of air from the outlet into the fan. The fan supporting shaft 50 projects upwardly above upper bearing 42 where it carries a pulley 52 drivable by belt 54 which extends outwardly through the side of the cabinet 20 into the motor cabinet 55 attached to the side of the main cabinet 20 and containing an electric motor 56 for driving the fan. The upper end of shaft 50 and the pulley 52 are closed by an internal box structure 58, and the side openings therein through which the belt 54 extends outwardly to the motor are protected by tubular casings which enclose the two runs of the belt 54 in cooperation with a box 58 and housing 55, the casing tubes 60 being substantially sealed to the openings through which the belt extends. As best shown in FIG. 3, the box 58 is also shaped to minimize flow restriction.

Horizontally mounted in a lower portion of the cabinet structure directly above the fan entrance is a shutter assembly generally designated operable to close or open the inlet when desired. As also shown in FIGS. I and 2, the cabinet may be somewhat wider in one dimension than is needed for the air flow requirements, leaving a space 68 for electrical and control components and which is compartmented from the remainder of the upper portion of cabinet by a partition 70 and accessible through a removable access panel 72.

The efficiency of the fan is increased by the provision of a stationary straightening vane plate formed of a flat piece of sheet metal extending across the inlet cone 46 close to the shaft and projecting downwardly a substantial distance into the fan wheel, parallel to the axis. The plate 75 stops lateral airflow through the wheel and prevents rotation of the inlet air.

In a preferred embodiment the fan has concave blade surfaces facing forwardly in'the direction of rotation, as indicated by the arrows in FIG. 2, which is quieter than the reverse rotation. The details of the fan rotor may be varied as engineering and performance requirements may dictate, but it has been found that with such a straightening vane, and a shroud band 45 which covers between 33 and 50 percent of the axial length of the rotor, it is possible to obtain full output from a fan wheel having forwardly directed blades despite the omission of a conventional scroll housing. High fan output is thereby obtained with low air noise.

This Detailed Description of the Preferred Embodiment of the Invention, and the accompanying drawings, have been furnished in compliance with the statutory requirement to set forth the best mode contemplated by the inventor of carrying out the invention. The prior portions consisting of the Abstract of the Disclosure and the Background of thelnvention are furnished without prejudice in an effort to comply with administrative requirements of the Patent Office.

I claim:

I. A direct fired air heater adapted for roof installation comprising a cabinet structure having a vertical air passage therethrough, roof mounting means attached to an intermediate portion of the structure for supporting the same in an opening in a roof whereby said structure projects both above and below the roof, characterized by air inlet means and heating burner means in said structure and both of which are located above said roof mounting means, said burner means having exposed flame discharge means in said vertical air passage, a centrifugal fan impeller mounted in said structure on a vertical axis at a position below theroof mounting means and having a 360 outlet, for drawing air downwardly from the air means through said vertical passage and over the exposed flame discharge means and outwardly through said 360 outlet.

2. An air heater as defined in claim 1 wherein said impeller rotates on a vertical axis, a shaft for driving the impeller extending upwardly from the impeller inside the cabinet structure to a position above the mounting means, and a motor carried by and on the outside of the structure above said mounting means for driving the shaft and impeller.

3. A direct-fired air heater adapted for roof installation comprising a cabinet structure having a vertical air passage therethrough, mounting means attached to an intermediate portion of the structure for supporting the same in a roof opening whereby said structure projects both above and below the roof, characterized by a centrifugal fan impeller mounted in the portion of said structure which projects below the mounting means and having a 360 outlet, heating and air inlet means carried by the structure above said mounting means, the upper end of the cabinet structure being open, a caplike entrance hood overlying and extending outwardly from and downwardly in outspaced relation around the cabinet structure to define upflow air inlets, and air filter means in and accessible through said inlets.

4. A direct-fired air heater adapted for roof installation comprising a cabinet structure having a vertical air passage therethrough, mounting means attached to an intermediate portion of the structure for supporting the same in a roof opening whereby said structure projects both above and below the roof, characterized by a centrifugal fan impeller mounted in the portion of said structure which projects below the mounting means and'having a 360 outlet, heating and air inlet means carried by the structure above said mounting means, said impeller being mounted to rotate on a vertical axis and said portion which projects below the mounting means defining a cage opening laterally in an area peripherally around the impeller, an axial inlet to the upper end of said impeller from the interior of said cabinet structure, and a baffle extending axially downwardly around the same from the cabinet structure to a position between the ends ofthc impeller.

5. An air heater as defined in claim 1 wherein said impeller rotates on a vertical axis and said portion which projects below the mounting means defines a cage opening laterally in an area peripherally around the impeller, an axial inlet to the upper end of said impeller from the interior of said cabinet structure, and a concentric annular baffle radially outspaced from and extending downwardly around the impeller from the cabinet structure for a distance equal to from 33 percent to 50 percent of the axial length ofthe impeller.

6. An air heater as defined in claim 4 including means for rotating the impeller in one direction, the impeller having a plurality of axially extending generally radial blades having concave surfaces facing forwardly in the direction of rotation.

7. An air heater as defined in claim 5 including means for rotating the impeller in one direction, the impeller having a plurality of axially extending generally radial blades having concave surfaces facing forwardly in the direction of rotation.

8. In an air heater as defined in claim 7, baffle means in the inlet of and extending axially and radially of said impeller and part way into the same to block rotation of inlet air about the axis of the impeller.

9. In an air heater as defined in claim 6, baffle means in the inlet of and extending axially and radially of said impeller and part way into the same block rotation ofinlet air about the axis of the impeller.

AI-Ill UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.

Dated NOV. 24, 1970 Inventorsfi James V. Dirkes It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line 11, after the word "air" insert the word -in1et--. Column 4, line 36, after the word "same" insert the word -to-.

I Attest:

Edward m. mm 11-;

Officer UiCri'EEJ firm SLY-MID U1 2 19?! WW E. SQEUYLER, J Gonmissioner of Patent

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