US3680974A

US3680974A - Transverse-flow blower and housing

Info

Publication number: US3680974A
Application number: US76691A
Authority: US
Inventors: James L Smith
Original assignee: Lau Inc
Current assignee: Lau Inc
Priority date: 1970-09-30
Filing date: 1970-09-30
Publication date: 1972-08-01
Anticipated expiration: 1989-08-01
Also published as: JPS4939562B1

Abstract

A blower housing for a tangential blower is formed of structural members made essentially of aluminum extrusions. A back member is formed with a cylindrical inside surface and approximates a volute with the blower wheel circumference. A reversible cut-off section provides selection over air delivery rates. A twin blower embodiment uses common extruded end frames.

Description

United States Patent Smith [451 Aug. 1, 1972 [54] TRANSVERSE-FLOW BLOWER AND 1,705,200 3/1929 Morse ..415/219 HOUSING 3,150,816 9/1964 Laing ..415/54 Inventor: James L. Piqua Laing [73] Assignee: Lau Incorporated, Dayton, Ohio FOREIGN PATENTS OR APPLICATIONS 22 i Sept 30 1970 397,138 12/1958 Switzerland ..415/54 986,096 3/1965 Great Britain ..415/54 [211 P 76,691 997,196 7/1965 Great Britain ..415/54 [52] U.S. Cl. ..415/54, 415/148, 415/219, Primary Ex min r-H nry F. Raderazo Y 414/200 Att0rney-Marechal, Biebel, French & Bugg [51] Int. Cl ..F04d 17/08, F04d 29/40, F04d 27/00 [58] Field of Search ..415/54, 219, 214, 423, 200, [57] ABSTRACT 415/148 A blower housing for a tangential blower is formed of 56 R f Ct d structural members made essentially of aluminum ex- 1 e erences e trusions. A back member is formed with a cylindrical UNITED STATES PATENTS inside surface and approximates a volute with the blower wheel circumference. A reversible cut-off sec- 3,200,609 8/1965 Laing ..415/54 i provides Selection over air delivery rates. A i 3,209,989 10/1965 ECh ..415/54 blower embodiment uses common extruded end 3,275,224 9/1966 Bush ..415/54 frames 3,308,268 3/1967 Laing ..415/54 1,462,890 7/1923 Taylor ..415/219 8 Claims, 6 Drawing Figures PATENTEDAUE' 1 I972 sum 1 0F 2 m/vs/v TOR JAMES L. SMITH B) v WM MM$ I ATTORNEYS v PATENTEDAUE 1 m2 SHEEI 2 [IF 2 FIG-6 BACKGROUND OF THE INVENTION Tangential or transverse-flow blowers are commonly made to lengths which substantially exceed the diameter of the blower wheel. In the past, low-cost units of this type have had housing made essentially of sheet metal. This required that the sheet metal parts be individually fabricated to a given length and then assembled. An example of this type of construction is shown in the patent of Kinsworthy US. Pat. No. 3,251,540 of 1966. A problem in the manufacture of blower housings of this type resides in the difficulty of maintaining accuracy of registration of the various parts. The tangential blower is sensitive to configuration changes, particularly at the cut-off section, and errors in positioning of this section with respect to periphery of the wheel-as small as one-sixteenth of an inch can result in a substantial change in performance.

SUMMARY OF THE INVENTION The present invention is directed to an improved blower and housing construction having a high degree of dimensional accuracy and more particularly to a housing which is formed essentially of extruded components. In the preferred embodiment, a blower housing is provided for a cross-flow blower in which at least the interconnecting scroll back and cut-off sections are formed of extrusions, such as aluminum. The end frames may also be formed of extruded sections. These extrusions may be made to an indefinite length and severed or cut to the desired finished length. Preferably, the longitudinally extending extruded portions are formed with integral screw-receiving protuberances or lips for ease of direct attachment to the end frames. v

The construction is one in which the parts are reversible, according to mounting or drive requirements. Further, the end frames are preferably fonned of channel section material so that the side flanges form a convenient means for mounting the blower housing.

The attachment lips for the cut-off section may be made somewhat offset or asymmetrical with respect to the geometric center of this extrusion, thus permitting the extrusion to be turned end-for-end to vary the clearance between it and the periphery of the blower wheel to control the output of the blower. In this simple manner, the blower may be tailored for a particular use, where a given output or a specific control of blower noise is desired.

It is accordingly an important object of the invention to provide a blower housing for a tangential blower in which the housing major parts are formed exclusively of extruded material, such as aluminum, to maintain accurate dimensional control of the parts.

Another important object of the invention is to provide a blower in which the transverse sections and/or the end frames may be made to an indefinite length and then cut to a desired length. This feature of the invention, when applied to a tangential blower, pemiits the blower housing to be made readily to any convenient length according to its desired use. Twin or multiple blowers may readily be assembled on common end frames.

A further object of the invention is the provision of a low-cost and structurally rigid housing for a cross-flow blower.

These and other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a blower housing constructed according to this invention showing the blower wheel and drive motor in place;

FIG. 2 is a partially broken-away side elevation looking at the exit region generally along the line 2--2 of FIG. 3;

FIG. 3 is a transverse section taken generally along the line 3-3 of FIG. 2;

FIG. 4 is an end elevation looking at the motor mounting end of the housing and being partially broken away to expose the cut-off section;

FIG. 5 is an enlarged fragmentary perspective portion of the cut-off section; and

FIG. 6 is a view similar to FIG. 3 of a modification of the housing for a twin blower.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIG. 1, an improved blower housing constructed according to this invention is illustrated generally at 10 as including a pair of spaced apart

end frame members

11 and 12 which are connected by a back 14 and a cut-off section 15. A tangential blower wheel 20 is received within the housing and is mounted for rotation, at one end, on a shaded pole electric drive motor 22 and on a suitable bearing 23 mounted on the opposite end frame 11. The wheel 20 may be constructed according to the teachings of Wentling US. Pat. No. 3,385,511 of 1968 and assigned to the assignee of this invention.

Referring to the details of FIGS. 2-5, it may be seen that the

end frames

11 and 12 are preferably formed of channel-shaped extruded material, preferably aluminum. These frame members may be made from the same extrusion and thus may be initially formed as an extrusion of indefinite length, and then suitably cut to a rectangle or substantially square size, as needed. However, the end frames may be stamped or molded. Each end piece is formed with a shaft access opening 21 and may be drilled with holes so as to accomodate either the mounting lugs of the motor 22 or the end bearing 23 so that, in this regard, the end frames are interchangeable. Pairs of the frame members may be drilled simultaneously in face-to-face relationship with holes for the purpose of attaching the back 14 and the cut-off section 15. Further, the end flange portions 24 of the

end frames

11 and 12 conveniently provide a means by which the housing 10 may be supported and mounted. I

The

end frames

11 and 12 are supported in spaced apart relation by the back 14 and the cut-off section 15, forming a rigid, box-like structure. The back 14 is formed as an extrusion of indefinite length and then cut to a desired length. Aluminum is preferred although plastics may also be used. It is formed with a smooth semi-cylindrical inner surface 26 and extends arcuately for about When it is mounted between the end plates or frames it forms a scroll-like air-directing surface, and also provides rigid support for the end frames. The outer surface is formed with three pairs of continuously extending lips 30 by means of which the back may be attached to the end frames. For this purpose,

self-tapping screws 32 are inserted through the openings in the end frame members and cut their own threads when driven into the semi-circular region defined between the pairs of lips 30.

The cut-off section is also formed as an extrusion of indefinite length, and then cut to the same length as the back 14. It is also formed with two sets of the lips 30 by means of which this section is secured between the end frames. Since the section is positioned diagonally opposite the open side of the back 14 it contributes to the strength of the housing 10. The wheel is formed with a radius which is approximately one-half that defined by the inside surface 26 of the back 14. The wheel is not mounted centrally of the

end frames

11 and 12 but is mounted in offset relation to the center toward the forward end 34 of the back. In this position, the wheel periphery 35 runs in somewhat closely spaced relation to the inwardly extending end 36 of the section 15, defining a space 37 therewith. Further, the periphery 35 of the wheel 20 defines, with the inner cylindrical surface 26, a region of expanding size leading from the entry region 40 to the exit region 42 OF the blower. This space approximates a volute, and the curved cylindrical outer surface 44 of the section 15 forms, in effect, a smooth continuation of the volute. In this manner, simple-to-form extrusions having essentially cylindrical surfaces comprising the

parts

14 and 15 closely approximate a housing of ideal efficiency at a substantially lower cost than that which would be required to process extrusion dies with compound curved surfaces.

The attachment lips 30 of the cut-off-section 15 are not formed centrally but are asymmetrically positioned in such a manner that the end 36 is of a somewhat longer length than the opposite 36 as seen in FIG. 5. As shown in FIG. 3, end 36 is positioned adjacent to the periphery 35 of the disk 20 and defines a relatively small clearance space 37 therewith. This arrangement is one which will provide the maximum velocity of air for a given rpm of the wheel 20. However, it is accompanied by a somewhat increased noise factor. The noise of the blower can be materially reduced with only a slight reduction in efficiency by turning the section 15 end-for-end so that the lip 36' is the one which provides the cut-off function at the exit region 42. Such a condition is shown in FIG. 4 in which the space 37' has a slightly greater radial dimension than the space 37 of FIG. 3.

Where all of the components structural of the housing are formed exclusively of extruded aluminum, a low-cost yet rugged housing is provided. Rigid vinyls, ABS, or other extrudable plastic materials may also be used. Such a housing can be made as desired, to any convenient axial length merely by trimming the

parts

14 and 15 to such length. In this manner, transverseflow blowers of varying lengths can be made from a given stock of extruded materials. When these parts are secured to the end frame members by the self-tapping fasteners 32, a dimensionally arcuate box-like rugged structure is formed which is highly resistent to deformation and twisting loads. The use of extruded parts permits ease of attaining dimensional accuracy in production, while substantially lowering production costs as compared to a sheet metal construction.

As noted above, the end frames 12 are preferably formed of extruded material, and this readily permits the use of end frame material of an extended length for the purpose of accomodating two or more blowers on common end frames. Reference may be had to FIG. 6 which shows a twin tangential blower housing in which a pair of back members 140 and 14b are positioned in back-to-back manner on a common elongated end frame 12. Corresponding cut-off sections 15a and 15b are associated with the back members to form a twinoutlet blower housing. The back members and cut-off sections are the same as those previously described and are merely turned end-for-end with respect to each other, and are secured to the elongated end frame 12' in the same manner as previously described in connection with FIGS. l-5. Separate wheels 20, bearings 23 and drive motor 22 are used, as above, to form a twin blower.

The arrangement illustrated provides a generally common inlet region 40' and a pair of

opposite exit regions

42a and 42b. The inlet region can be separated into two regions if desired. It is obvious that the same parts can be arranged between the end frames to provide 180 opposed inlets and a generally common exit region, as desired.

While the forms of apparatus herein described constitutes preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention.

What is claimed is:

1. A tangential blower, comprising a pair of axially spaced apart end frames, an intermediate curved back member positioned between said frames and having a semi-cylindrical inside surface, a tangential blower wheel mounted for rotation between said end frames and having a radius less than that of said back member and being mounted with its axis of rotation offset forwardly from the center of curvature of said back member defining with said back member a space approximating a volute including an entry region leading arcuately to an exit region, and an arcuate cut-off section extending between said end frames having means defining an inner lip positioned closely adjacent the periphery of said wheel at said exit region for one flow condition through the blower and means for reversing the arcuate cutoff section to give a second flow condition through the blower.

2. The blower of claim 1 in which said end frame, said back and said cut-off section are extrusions.

3. The blower of claim 1 in which said cut-off section is formed with a curved outer surface.

4. The blower of claim 1 in which said back member and said cut-off section are formed of extruded material and define integral self-tapping fastener openings, and self-tapping threaded fasteners extending through said end plates and engaging said back member and said cut-off sections at said openings.

5. The blower of claim 1 in which said cut-off section is formed with an opposite pair of cut-off lips and with mounting means opposite from the center thereof, said cut-off section being reversible with respect to said end frames to provide selection in the spacing between said section lips and said wheel.

respect to said lips whereby when the opposite lip is positioned adjacent said blower wheel the output from the blower is varied.

8. The tangential blower of claim 7 in which said housing defines a blower back formed with a cylindrical curvature which approximates a volute with respect to the periphery of said wheel, and in which said cut-off section is formed with a cylindrical outer surface.

l I III

Claims

6. The blower housing of claim 1 in which said end frames, said back and said cut-off section are formed exclusively of aluminum.

7. In a tangential blower assembly including a blower housing and a tangential blower wheel mounted for rotation in said housing, the improvement comprising a cut-off section having a pair of opposite lips, and means on said cut-off section for mounting said cut-off section selectively with one of said lips adjacent said blower wheel, said mounting means being asymmetrical with respect to said lips whereby when the opposite lip is positioned adjacent said blower wheel the output from the blower is varied.