US 2803398 A
Description (OCR text may contain errors)
Aug. 20, 1957 v. E. SPROUSE ,3
CONVEX BACK PLATE BLOWER WHEEL Filed May 11, 1956 FIE-3 JINVENTUR v l/EE/VE'E E 51390055 ATTURWE? United States Patent O F CON /EX BACK PLATE BLGWER WHEEL Verner E. Sprouse, Columbus, Ind, assignor to Vernco Corporation, Columbus, Ind, a corporation of Application May 11, 1955, Serial No. 534,2il9
3 Claims. (Cl. 239-134) This invention relates to a blower wheel construction of that type commonly employed in automobile heater units, oil burners for domestic heating plants, and the like. The invention particularly relates to a blower wheel wherein there is a convex back plate buldging forwardly a sufiicient distance to permit carrying the back plate substantially over if not entirely over a driving motor in order that the blower wheel and motor may be fitted into extremely limited space locations such as now exist in the modern automobiles.
A primary object of the invention is to provide a blower wheel which, employing the convex back plate which protrudes within the wheel proper, will provide a maximum delivery of air by the wheel without building up turbulence and hence back pressure within the wheel around the entering back plate.
A further important object of the invention is not only to achieve that result, but to do so within the limited axial length permitted of the blower wheel. The diameter of the wheel is also generally limited in order to permit the wheel to be accommodated in the permitted space.
These and other important objects and advantages of the invention will become apparent to those versed in the art in the following description of the form of the invention as now best known to me, as illustrated in the accompanying drawing, in which Fig. 1 is a view in side elevation of a wheel embodying the invention;
Fig. 2 is a view in front elevation or delivery end of the Wheel; and
Fig. 3 is a view in transverse section on the line 3-3 in Fig. 2.
The blower wheel, generally designated by the numeral 19, is made up to have curved blades 11 spaced circumferentially around the wheel between front and back members 12 and 13 respectively, the member 12 being a ring through which air is delivered, and the member 13 indicating generally a back plate.
The major portion of the back plate 13 bulges inwardly or forwardly of the wheel as indicated in Figs. 1 and 3 to have a generally frusto-conical shape, forming in effect a dome, and generally indicated by the numeral 14. Thus, the member 14 has a sloping wall 15 which extends around through a radius 16 into a more or less planar surface 17 substantially at right angles to the axis of the wheel.
This planar portion 17 carries a shaft mounting hub 18 axially thereof. As indicated in Figs. 1 and 3, the hub 18 extends by its major axial length forwardly of the area 17.
Each of the blades 11 has a full width back to the plane of the area 17, and from that plane, each blade has its inner edge sloping toward the outer edge 19 and to the rear end thereof. The blades 11 are thereby reduced in width through that length of the wheel along which the back plate portion 14 extends. As one particular ex- 2,803,398 Patented Aug. 20, 1957 MIC ample, without limiting the invention thereto, assuming the diameter of the wheel to be 6% inches in diameter across the outer edges 19 of the blades 11, and a wheel length of 3 /8 inches, and using blades 11 which are of an inch in overall radial width, the axial length of the dome portion 14 of the back plate 13 as indicated by the letter A would be 1 inches; the diameter of the base of the dome 14, as indicated by letter B, would be substantially 4% inches; the length F, that is the fullwidth portion of each blade 11 would be 1 inches; and each blade 11 would slope from the intersection of the plane of the area 17 rearwardly to a point spaced a distance G from the base of the dome 14, measuring /2 of 1 inch; the distance from the Wall 15 of the dome 14 at the intersection with the radius of curvature thereof extending into the area 17 to the diagonal line 20, as indicated by letter H, would be of an inch.
By these dimensions it will be seen that the diagonal line 20 is not parallel to the side wall 15, but slopes under the dimensions G and H to give a slightly wider clearance for the H dimension as compared to the G dimension. The H dimension would be measured across from the end of the straight Wall 15 on the diameter indicated by the letter C, which dimension would be approximately 4 inches.
In giving the specific size of structure, in accordance with the dimensions indicated, it is to be kept in mind that the back plate 13 may vary in shape, that is in accordance with its diameter and its length extending into the wheel, the diameter of the wheel itself, the length of the wheel, the number of blades 11 employed, the widths of the blades, all of which would afiect the clearance between the diagonal line 24 and the side of the inwardly protruding wall 15 of the dome 14. In any event, the general construction remains, and there is an increasing clearance between the forward end of the digonal line 20 of each blade as compared to its rear end adjacent the radial portion of the back plate 13 which extends outwardly and is secured to the individual blades 11. The dimension D as indicated in Fig. 1 for the set of dimensions given would be approximately 3 /8 inches.
By reason of this peculiar construction, there is an interrelationship between the diagonal end portions of the blades and the inwardly protruding portion of the back plate 13 whereby the rear end portions of the blades, being reduced in width and then increasing forwardly to the full width, will set up a gradually increasing pressure flow of air along the surface of the dome across the wall 15 to enter into the full flow from the full width portions of the blades, all without producing an interrupting turbulence or back pressure which would reduce the overall permissible output of air delivered by the blower.
A motor (not shown) may be mounted in a fixed manner upon some support whereby the motor is largely within the dome 14 of the back plate 13, thereby conserving the space allocated for the blower wheel and its motor, all without requiring a shorter length of blade.
Therefore, while I have herein shown and described my invention in the one particular form, it is obvious that structural changes may be employed, particularly in the shape of the back plate 13, shape of the blades themselves, the particular engagement of the ring and back plate with the ends of the blades, and the ratios of dimensions G and H, all without departing from the spirit of the invention, and I therefore do not desire to be limited to that particular form, beyond the limitations which may be imposed by the following claims.
l. A cylindrical blower wheel having a plurality of circumferentially spaced apart blades extending by straight line outer edges along the periphery of the wheel straight edges extending from forward ends substantially 7 parallel to said axis and to a plane normal to said axis approximately at the forward end of said plate portion, and from which plane said blade inner edges each extends in a straight line diagonally from said plane to said blade rear ends defining an annular space approximately fixed in radial width between those diagonal lines and the periphery of said plate portion.
2. The structure of claim 1 in which said diagonal edges of said blades are approximately parallel to right lines of said hub portion.
3. The structure of claim 1 in which the radial width of said annular space is on the order of a half unit compared to a major diameter of said plate portion of approximately four and three-quarters units.
References Cited in the file of this patent UNITED STATES PATENTS 1,730,372 Lawrie Oct. 8, 1929 1,892,930 Burman Jan. 3, 1933 2,329,696 Chester Sept. 21, 1943