US 3811790 A
A central station air moving apparatus is disclosed incorporating an irregular heptagonal configuration and an air outlet damper device mounted on one side of the heptagon.
Description (OCR text may contain errors)
United States Patent [191 Mikulina et al.
[111 3,811,790 [451 May 21, 1974 [5 AIR MOVING APPARATUS  Inventors: Thomas W. Mikulina, La Crosse;
. Ronald J. Liev ens, Onalaska; George T. Brockman, Stoddard, all of Wis.
 Assignee: The Trane Company. La Crosse,
 Filedi May 8, 1972  Appl. No.: 251,124
[52'] US. Cl. 415/145, 415/206, 415/219 C I  Int. Cl..... F04d 29/46, F04d 29/56 v , Field of Search 415/204, 206, 219 C, 145,
 References Cited UNITED STATES PATENTS 2,649,242 3/1953 Payne 415/145;
2,143,335 Toler 415/204 2,301,857 11/1942 ,Crigui 415/204 2,994,348 8/1961 Cape. 415/206 3,561,906 2/1971 Fermer 415/206 v FOREIGN PATENTS OR APPLICATIONS 8/1952 Germany 415/219 C OTHER PUBLICATIONS Publication: Buffalo," Bulletin F-lOO, Cover page & I
page 14, Buffalo Forge Co., Dated 104953.
Primary Examirief+Henry F; Raduazo 57 1 ABSTRACT A central station air moving apparatus is disclosed incorporating an irregular heptagonal configuration and an air outlet damper device mounted on one side of the heptagon. I 1 Claim, 5 Drawing Figures PATENTEDHAYZI m4 SHEEI 1 [If 2 FIG.
FIG/2 PATENTEDIAYZI m4 3811790 FIG. 4
FIG 5 AIR MOVING APPARATUS BACKGROUND OF THEINVENTION -In the air conditioning of large and/or multiroomed buildings, either through heating or cooling, air is often tems of the aforementioned types is a relatively difiicult v and expensive process. The need therefore exists for a large sized centrifugal fanhousing thatis less costly and more simple to build, and which can be used in. conjunction with a simple, economical fan output modulation system.
SUMMARY OF THE INVENTION It is therefore an object ofjthe present invention to provide a simply constructed and economical fan housing for relatively large sized centrifugal blowers.
' A further object is to provide a fan output modulation system that is compatible with and particularly suited to the new fan housing.
The present invention provides a central station air handling apparatus that includes a fan housing, a sup port framefor the housing, one or more centrifugal 'fan wheels mounted for rotation within the housing, an air inlet cone for each fan wheel, and an output modulating damper assembly; the fan housing being in the shape of'an irregular polygon having more than four sides.
- DESCRIPTION OF THE PREFERRED I EMBODIMENTS and a second inlet cone 31 on the opposite side. Moreover, the fan wheel employed in the present invention may be either a single width wheel as shown in FIGS. 14, or a double width wheel as shown in FIG. 5.
While the peripheral walls 18, 20, 22, 24, 26 and28 can be of varying dimensions, economies can be realized in manufacture if peripheral walls 18 and 20 are equal in length, as viewed for example in FIG. 2; and peripheral walls 22, 24 and 26 are also equal in length. Accordingly, dimensioning in the manner described is preferred.
Fan housing 10 is supported on frame 32, which includes legs 34 and 36, horizontal cross members 38 and 40, top bracket 42, and cross braces 44. It will be appreciated that the precise geometry of the frame can be varied considerably by those skilled in the art. Horizontal cross members 40 support bearings 46 which in turn rotatably support'shaft 48. Shaft 48 may be rotated by any suitable power transmission arrangement, and is commonly driven by belts and pulleys not shown.
Fan wheel 50 is mounted for rotation on shaft 48. As has been pointed out, fan wheel 50 can be of the single width type shown in FIGS. l-4, or the double width type shown in FIG. 5.
While in the drawings fanwheel 50 is illustrated as having backwardly inclined blades, it will be understood that the present apparatus may employ radial fan blades or forwardly curved fan blades as well, although the apparatus has been found to be particularly well adapted to use with backwardly inclined fan blades which are preferred.
Peripheral wall 28 includes a cut-away portion at 29,
' over which damper box 52'is mounted. Damper box 52 is comprised of a frame 54 supporting a series of louvered blades 56 which rotate about shafts 58. The
. damper blades may be opened and closed manually or Certain embodiments of the present invention will be I I described in greater detail with reference to the accompanying drawings inwhich:
FIG. 1 is a perspective view of an air handling apparatus embodying the features of the present invention,
FIG. 2 is a side view in elevation of the apparatus of FIG. l,v
having a fan housing indicated generally at 10. The housing includes side walls 12 and 14 and peripheral walls l6, 18, 20, 22, 24, 26 and 28. At least one of the side walls 12 'or 14 has a generally circular opening for mounting an inlet cone 30 and/or 31. It'will be understood that the present design is applicable to both single inlet fans, as shown for example in FIGS. I4, and to double inlet fans, as shown in FIG. 5, both types of fans being well known in the art. Accordingly, the single inletfan will have a single inlet cone 30, whereas a double inlet fan will have an inlet cone 30 on one side been illustrated in relationship to peripheral wall 28, it has been found that the damper box may also be mounted on peripheral wall 26 or 24 if desired without departing from the scope of the invention.
Damper box 52 is employed as a fan modulation device by discharging a portion of the air moved by the fan wheel through the damper section rather than delivering the air to the fan outlet. Air discharged through the damper box is recirculated to the fan inlet. In some central air handling installation, the fan room itself is used as a return air plenum, in which case damper box 52 would simply exhaust air to the room plenum. Other central air handling installations employ ducted fan in lets, and in such an installation, damper box 52 would be'ducted to the fan inlet duct. Because air is continually delivered to the fan and passes through the fan wheel either to the fan outlet or through damper box 52, the system allows the fan to be operated at substantially zero air delivery without causing the fan to stall.
As indicated in the drawings, the fan housing 10 takes the general configuration of an irregular polygon, having in the illustrated embodiments seven sides. The polygon is irregular in that the sides are not all of equal length, but the included angles between the sides are equal angles. The irregular heptagonal shape illustrated has been found to be of considerable benefit in the manufacture of large fans. The flat peripheral walls 16, 18, 20, 22, 24, 26, and 28 are simpler and less costly to form. and assemble than the conventional smooth spiral fan housing common use. Moreover, the performance of the heptagonal housing has been found to be comparable to the more smoothly curved fan housings. Also, the flat peripheral walls are well adapted for mounting of damper box 52 in a simple and secure manner inasmuch as the wall is a flat rather than curved surface. The damper box 52 is mounted exteriorally of the fan housing and the damper mechanism does not interfere with the smooth flow of air through the interior of the fan housing.
1. Air moving apparatus including a fan housing having axial spaced side walls; a centrifugal fan wheel adapted for rotation about a shaft within said housing,
a frame means for supporting said housing; said frame means including mounting means for said shaft. at least one air inlet portion in fluid communication with said fan wheel in said side walls; an air outlet portion formed by said housing for the discharge of air moved by said fan wheel, said housing including a plurality of substantially flat peripheral walls greater than four extending between said axially spaced side walls; a damper box mounted on an opening in the peripheral wall exterior of said housing upstream of said outlet portion; said damper box including a frame, a plurality of shafts rotatably supported in said frame, each of said shafts having a damper blade fixed thereon for rotation with said shafts, said shafts being oriented substantially parallel to the air stream flowing through said outlet portion when said-damper blades are in the fully closed position.