US 1939356 A
Description (OCR text may contain errors)
r Dec. 12, 1933. H. o. LINDGREN 1,939,356
PRQCESS OF PRODUCING CONICAL DISKS FOR CENTRIFUGA L SEPARATORS Filed 001',- 12, 1929 J urn me Patented Dec. 12, 1933 UNITED STATES PATENT OFFICE PROCESS OF PRODUCING CONICAL DISKS v FOR CENTRIFUGAL SEPARATORS Hans Olof Lindgren, Appelviken, Sweden, as-
signor to The De Laval Separator Company, New York, N. -Y., a corporation of New Jersey Application October 12, 1929, Serial No. 399,408,
and in Germany November 3, 1928 4 Claims. (01. 113-52) Centrifugal separator bowls; particularly cream of the cone, and the thickness of the original sheet separators, are usually provided with a series of iron is equal to or smaller than the sine of the superposed plates of frusto-conical shape, pophalf top angle of the cone. ularly called disks, which divide the separat- By the half top angle of the cone is meant that ing space of the bowl into thin strata and greatly angle which is formed, in a vertical section taken promote efiicient and rapid separation. Each of through the axis of the conical mantle, between these disks or cones is usually provided with an such axis and the wall of the conical body of the outwardly extending peripheral flange at its widmantle. er end and an inwardly extending flange at its In order to obtain the desired displacement of narrow end. Since one of the factors on which the material it is necessary that the sheet iron shall 65 skimming efficiency of a bowldepends is the dihave a suitable hardness. In the spinning operavision of the separating space of the bowl into the tion, the initial blank should have the shape of 2. largest practicable number of layers, it is desirable flat sheet of even thickness and should be posito make the conical portion of the disk as thin as tioned at about right angles to the axis of the possible so that the largest practicable number of spinning element. 7
disks may be placedwithin the bowl. On the other If thedesired relation between the thickness hand, the peripheral flanges should be as thick as of the conical mantle and that of the flanges shall. is consistent with the maintenance of flanges of be equal to the sine of the half top angle of the adjacent disks properly spaced apart, because cone, the semi-manufactured disk canbe prothe thicker the flanges, the stiffer, and conseduced in a single operation. 7 quently the stronger, the disks. It is, of course. If the desired relation between the thickness possible to make the flanges thicker than the of the conical mantle and that of the flanges shall conical disk body because the body extends at a be less than the sine of the half top angle of the steep angle to itsaxis whilethe flanges extend cone, the spinning operation should be such as to at a wide angle to the axis, normally, but not produce a semi-manufactured disk whose top anso always, at a right angle thereto. gle is smaller than that of the finished disk. The
, Heretofore the first stage of manufacture has disks can then be shaped to final form and fininvolved the production of disks with conical body ished by pressing or by the usual spinning. and flanges of uniform thickness, the conical body If t desired thickness of the Outer flange i being subsequently thinned to the desired delessthan ot the original material but greater 85 gree by turning or grinding. This method of prothan that of the conical mantle, I produce, by duction is, however, open to serious objections. spinning, a semi-manufactured disk in the shape Such disks, if of iron, are more exposed to rust of two conical mantles, one below the other, than disks which have not been worked with cutthe top angle or the lower mantle being made ime l pr ly b cause the surface of the greater than that or the upper mantle. By bend- 9o material is compressed in the rolling operation and ing up th lower a tl t fQrm a, flange, th r also because the original surface is less contamibt d a di k having a, body of the desired nated than the interior by slag impurities and 89$ reduced thickness an inner flange having the p f Furtherithe process. is expensive in that same thickness as that of the original material,
40 additional operations, for example, the turning, and an outer flange whose thickness is less than 95 are necessary, and that the loss of the considerable quantity of material that is turned off issubstanzgz gi gfi flange but greater than that of tial and, especially in the production of disks of In the production of disks or rustless metal it non-resistant metal, quite serious.
The present invention has for its object the prois possible to proceed as follows A semi-manuduction, as heretofore, of a disk comprising a thin fa'ctured disk in the 8.11am of frustum of cone conical mantle and thicker flanges, by a relativeis produced y spmr'nng' The upper part 15 bent ly simple and inexpensive process. It involves the to form, the Inner flange of the disk The Quter production of such disks from sheet iron or other flange formed by bending up the lower part metal having, preferably, the same thickness as of the cone to form flange of twice the desired 105 the inner flange, and the employment of a special Width and then bending this vflange upon itself spinning operation which efiects such a reduc- (double-bending) to form 9; flange of twice th tion in the thickness of the material that the rethickness of the conical Y- Y this P oc du lation between the thickness of the conical pora still outerflange is obtained, since the material tion, measured at right angles to the generatrix of the flange during the manufacture is also ex- 110 posed to cold-working so that the elastic limit of the material is considerably increased.
The several described mechanical manipulations constituting illustrative embodiments of my invention are shown in the accompanying drawing, in which Fig. 1 is a diagrammatic view of a disk blank, 9. die and clamp for holding the disk, and a spinning roller which cooperates with the die to shape the disk.
Fig. 2 is a view, similar toFig. 1., showing the disk spun to shape.
Figs. 3, 4 and 5 are diagrams showing modified manipulations embodying my invention.
Fig. 6 is a diagram showing the relation of the thickness of the conical body to that of the original blank.
In Fig. 1 a die 1: (shown broken away) having a conical periphery has clamped against its upper face a flat disk'blank a of uniform thickness. A spinning roller 1/ spins the blank into the shape shown in Fig. 2. In Fig. 2 the disk comprises an upper (inner) flange I) having the thickness of the original blank, a lower (outer) flange 0 having the thickness of the original blank, and a frusto-conical body (1 whose thickness relative to that of the original blank is equal to the sine of the half top angle of the cone.
In Fig. 3 the disk is produced by the same operation, but the body is thinner than in Fig. 2. This greater thinness is produced by first forming a body 6 (shown in broken lines) whose top angle is smaller than that of the finished disk and then expanding the body into its ultimate shape as indicated at f.
In Fig. 4 the upper part of the die has a periphery inclined at a relatively small angle to its axis and the lower part of the die has a periphery inclined at a relatively large angle to the axis, so that, at the conclusionof the spinning operation a disk body is formed having an upper frusto-conical part 9 extending at a relatively sharp angle to its axis and a lower frusto-comcal part h extending at a relatively wide angle to such axis. The lower part It is of greater thickness than the upperpart g and is bent up, as shown in broken lines, to form the lower (outer) .fiange. The lower part h, when bent out to form the lower flange, is of greater thickness than that of the body but of less thickness than that of the original blank.
In Fig. 5 a frustumi of a cone, of the desired thickness of the body, is produced by spinning. The upper part is bent in on the line w w to form the upper or inner flange. The lower flange 9' is formed by double-bending, as shown in broken lines in the figure.
The angle k in Figs. 1, 2 and 6 is the half top angle of the cone. If we assume that the blank is made up of many parallel strata perpendicular to its surface and that in spinning these strata are all displaced in the direction of their length as shown in Fig. 6, it may be readily seen that a cone with half top angle is made from a blank with thickness in will have a thickness t2=ti sine k.
The invention is not limited to the above described and illustrated embodiments, which illustrate several of numerous specific variations.
The terms upper or inner and lower and "outer" are used. in their relative sense, for convenience only, and are in accordance with the positions that the disks have in the usual bowl rotatable on a vertical axis. It will be understood,
however, that in the spinning operation the axis of the machine may be horizontal, in which case the blank would not be clamped against the upper face of the die.
Having now fully described my invention, what I claim and desire to protect by Letters Patent is:
1. That process of manufacturing centrifugal separator disks having flat flanges and an intermediate frustro conical body, which comprises forming a flat circular disk blank of approximately the same diameter as the finished disk, placing it on a conical form and by rolling an intermediate zone displacing the material therein axially only to form it into a frustro conical surface.
2. That process of forming centrifugal separator disks. having relatively thick fiat flanges and an intermediate relatively thin frustro conical body, which comprises forming a flat circular disk blank of a diameter approximately the same as that of the finished disk and of a thickness equal to that desired in the flanges, placing it on a frustro conical form and by rolling an intermediate zone in the blank displacing the material axially only to form said thin frustro conical body leaving the inner and outer portions unchanged to form relatively thick flanges.
3. In the manufacture of separator disks having inner and outer flanges and a conical intermediate body, the process which comprises forming a fiat circular disk blank of a diameter approximately equal to that of the finished disk and of a thickness substantially greater than the desired thickness of the conical intermediate body of the finished disk, placing the blank on a conical form/subjecting that intermediate portion of the blank extending from the desired outer diameter of the inner flange to the desired inner diameter of the outer flange to a spinning operation adapted to only axially displace said intermediate portion and thereby reshape it into a conical body having substantially the same minimum and maximum diameters as said inter mediate portion of the blank and simultaneously with such change in shape reducethe thickness of said intermediate portion so that it is equal to the thickness of the original blank multiplied by the sine of the half top angle of the conical portion.
4. In the manufacture of centrifugal separator disks having relatively thick inner and outer flanges and a relatively thin frustro-conical intermediate body. the process which comprises forming a flat circular disk blank of internal and external diameters approximately equal to that of the finished disk, placing it on a conical form, and subjecting only that intermediate part of the blank extending from the desired outer diameter of the inner flange to the desired inner diameter of the outer flange to a spinning operation adapted to so only axially displace the material of the blank as to reduce the thickness of and so elongate and expand said intermediate part as to reshape it into a frustro-conical body having substantially the same minimum and maximum diameters as said intermediate part of the 'blank, the resultant disk comprising a frustro-conical body composed substantially solely of the metal of said intermediate portion and end flanges from or into which substantially no metal has been drawn or forced in the spinning operation.
HANS OLOF' LINDGREN.