US 2652191 A
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Description (OCR text may contain errors)
Sept. 15, 1953 A. BUCH] 2,652,191
ROTOR FOR COMPRESSING MACHINES SUCH AS CENTRIFUGAL BLOWERS AND PUMPS Filed Dec. 50, 1947 2 Sheets-Sheet x Sept. 15, 1953 A. BUCHI ROTOR FOR COMPRESSING MACHINES SUCH AS CENTRIFUGAL BLOWERS AND PUMPS Filed Dec. 50, 1947 2 Sheets-Sheet 2 awe/WM ALFRED BUCHI Patented Sept. 15, 1953 ROTOR FOR COMPRESSING MACHINES SUCH AS CENTRIFUGAL BLOWERS AND PUMPS Alfred Biichi, Winterthur, Switzerland Application December 30, 1947, Serial No. 7 94,506 In Switzerland February 21, 1942 Section 1, Public Law 690, August 8, 1946 Patent expires February 21, 1962 3 Claims.
This invention relates to rotors for compressing machines such as centrifugal blowers and. pumps.
According to thepresent invention the rotor is composed of a driving disc and a closure disc overlying the latter each of said discs being integl-a'l with a section of the rotor blading and each of the complementary rotor blading sections havihg interengaging axially directed offsets. The
blade ends of the two rotor sections may interengage with each other'also in the radial direction. The two rotor sections are interconnected in the axial direction by connection elements. The rotor blades are, advantageously, provided with widened cross sectional portions adjacent to tenon shaped offset portions as well as at the points Where the connection elements are situated. Toward the base portions the cross section of the blades is, advantageously, enlarged. With af'viewfto providing foruniform thickness of the liladesectin at the joint the jointin portions about "the blading may be offset in both rotor sections relative to the blade base surfaces in such manner that 'fOr the manufacture of the dies for the blading, that is, for the machining of the blading itself by means of conical milling cutters the latter can be guided along the joint at a uniform distance from their axes of rotation. The two rotor portions can be produced by being milled out of solid material or in the form of a casting or a pressed piece.
Several embodiments of the invention are illustrated in the accompanying drawings, by way of example only, in which Fig. 1 shows a cross section of a single tage centrifugal blower on the line I--I in Fig, 2;
Fig. 2 shows cross section of the same blower but on the line II-II in Fig. l, and
Figs. 3, 4 and 5 are views of various details of the subject matter of the invention.
In Fig. l the rotor driving disc is designated by I and by 2 a closure disc overlying the same is referred to. The driving disc I is keyed to the driving shaft 3 by means of keys 4. The rotor I, 2 is inclosed in a two-part casing 5, 6 including an entrance funnel I, a spiral collecting space 8 and a delivery pipe connection 9. According to the invention the joint surface I0 between the two rotor sections I and 2 extending between the blading sections II, I2 on said sections I, 2 is stepped off in tenon shape so that a projection I3 on the blading section I2 fits in an all around tight manner in a recess I4 in the blading section II. For securing this tight fit connection elements I5 protrude through the two rotor sections. These connection elements I5 extend through the blading sections H and I2 'up to outer sides It and I! of the driving disc I and the closure disc 2 respectively. Advantageously, said elements are riveted down at their ends. The connection elements I5 are dimensioned so as to be capable of resisting the resulting axial and tangential strains.
In Fig. 2 the driving rotor section I is shown as well as individual blade sections II that are integral therewith and are provided with recesses I4 substantially in the middle thereof. The numeral l5 represents again the connection elements protruding through theblades.
In Fig. 3 the joint surface II! is provided with only one projecting offset I3 at the blade portions for interfitting in the axial. direction with a recess H3" in the individual blade sections I1.
Fig. 4 depicts another embodiment of the invention. The joint surface It thereof is S- shaped. A radially inwardly projecting nose I3" on the blade section I2 engages in a recess I4 in the blade sections l I of the rotor body I. The assembling of such a rotor is eiiected by axially pushing the rotor sections I, 2 into position of interengagement until the noses I3 can be pushed into the recesses I4 in the tangential direction, that is, in the manner of a bayonet joint.
Fig. 5, being a tangential section of the two rotor portions I and 2 within the embrace of the blade sections I l, I2 thereof, shows by the double arrows 20 and 20 on these sections that the blade thickness is smaller at the joint surface II) than at their bases 23 where said bases merge in the rotor discs I or 2. At the joint surface It! the blade sections have in both rotor section I, 2 approximately the same thickness. The joint surface Il) may mutually interengage each other in any other suitable manner, for example, be dove-tailed to each other. Alternatively, several projections I3 and recesses I4 may be consecutively arranged in the radial direction.
The offsets are arranged in the jointing portions of the blades, advantageously, suchwise, that the rotor section less strained, limits the stressing and the expansion of the higher strained rotor section by means of the jointing portions situated within the blades.
The arrangement may also be such that the rotor section less strained is shrunk on the higher strained rotor section, for example, by pressing or hot shrinking said sections into engagement with each other at their joining portions provided within the blading. By this means the rotor Conversely, by the term the higher strained rotor section I mean the impellor section which is subjected. to greater strain by centrifugal forces during operation. As will be readily appreciated by persons skilled in the art of blower impellor construction, with some designs, the impellor disc section may be less strained than the shroud section, while in other designs, the shroud section may be less strained and the impellor disc section, higher strained.
Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is:
1. A rotor for compressing machines such as centrifugal blowers and pumps which is composed of two sections confronting each other axially, one of said sections comprising a driving disc, blading portions extending at least partially axially from said disc, each of which blading portions is integral therewith, and the other section comprising a shroud ring, blading portions on said shroud ring integral therewith and extending toward said first blading portions to abut thereagainst, and interengaging shoulders on the abutting surfaces of said blading portions, the said abutting surfaces, excluding the shoulders, when brought together being comprised of two areas, one area lying substantially in a first plane normal to the rotor axis, and the other area lying substantially in a second plane also normal to the rotor axis, said two planes being set off axially from each other by a distance equal to the width measured axially of the blower of said shoulders, and said shoulders extending substantially perpendicularly to both of said two planes.
2. The rotor as defined in claim 1 wherein the shoulders on the blading portions of the rotor section, which during operation is subject to lesser stressing through centrifugal forces are faced radially inwardly, the shoulders of the section which during operation is subject to greater stressing through centrifugal forces are forced radially outwardly, and the radially inwardly facing shoulders are heat shrunk upon the radially outwardly facing shoulders thereby to set up in the last mentioned shoulders a compression which is opposed in direction to the stress created during operation by centrifugal forces, and hence to diminish stress intensity.
3. The rotor as defined in claim 1 wherein the shoulders on the blading portions which are integral with the disc face radially inwardly, the shoulders integrated with the shroud ring face radially outward, and the radially inwardly facing shoulders are heat shrunk upon the radially outwardly facing shoulders thereby to set up in the last mentioned shoulders a compression which is opposed in direction to the stress created during operation by centrifugal forces, and hence to diminish stress intensity.
References Cited in the file of this patent UNITED STATES PATENTS Date