US1530019A - Screen for centrifugal baskets - Google Patents

Description

March 17, 1925. 1,530,019

R. A. STEPS SCREEN FOR CENTRIFUGAL BASKETS Filed March 3 0, 1925 I 11v ENTOR Patented Mar. 17, 1925.

UNITED STATES PATENT. FFICE.

ROBERT ALEXANDER STEPS, OF LOS ANGELES, CALIFORNIA.

SCREEN OENTRIFUGAL BASKETS.

Application med March so, 1923. Se ial No. czssaa.

To all whom it may concern:

Be it known that 1, ROBERT ALEXANDER Srnrs, a citizen of the United States, residing at Los Angeles, in the county of Los Angeles and State of California, have in vented a new and useful Screen for Centrifugal Baskets, of which the following is a a specification.

This invention relates to screens such as are used in centrifugal baskets, and which are formed of a foraminous sheet bent into a substantiallycylindrical shape, the twoabutting edges being then more or less fastened together in some suitable manner.

Heretofore there have been various ways of fastening these edges, but for several reasons none. of these modes of fastening have been altogether satisfactory.

As is well understood the material such as sugar, for instance, which is treated in these centrifugal baskets, 1s finally d1s-.

charged therefrom by means of a discharging shoe, the sharp tip or point of which presses on the screen as the latter revolves with the basket slowly, during the discharging operation, thereby cutting the sugar or other material off the screen and d1scharging it through the bottom of the basket in a .well known manner.

As the discharging proceeds this shoe is gradually lowered along the screen by mechanical means, until all the material is presently discharged by the ac tion of this descending shoe scraping on the slowly revolving screen and basket.

Owing to this scraping action which the discharging shoe necessarily has on the screen, the mode in which the aforesaid abutting edges of the latter are oined together, must comply with some rather rigorous conditions which have not been well complied with in any of the joints heretofore proposed. In the first place the joint should be as fiat as possible, i. e., it should not be bunchy as occurs when the character of the joint involves too many layers of the sheet in making it, as thelatter produces a I only poorly solved could be cut or encountered by the relative" circumferential movement between the joint and the shoe. It'i-s true that screens heretofore proposed have no edges that encounter the shoe in the circumferential direction, but most of them have'upstanding edges that freely encounter and out against the shoe in its downward direction, and since thelatter is fully as important as the former, it is clear that the screens so proposed have the problem which con fronted them.

' By a novel combination and rearrangement which I will now describe, my invention has the double advantage of getting away from the objectionably thick bunchy joints that have heretofore been known, and at the same time getting away from any upstanding edge that could encounter the discharging shoe either in its relative down ward or circumferential movement, and

whilesecuring these extremely important advantages my invention further results in the very simplest possible kind of a joint, and perfectly satisfies all operating conditions or difficulties that could be encountered.

In the drawings Fig. 1 illustrates the foraminous sheet flattened out, part of the sheet being broken away for space economy. Fig. 2 is an enlarged View showing the two edges to be joined. Fig. 3 is a similar view after the edges are joined. Fig. 4 is a plan view looking down on the joint. Fig. 5 shows the foraminous sheet bent into cylindrical shape and joined, the dischargershoe being indicated more or less diagrammatically in its relation to the screen. Fig. (i is a more or less diagrammatic view showing the discharging shoe cutting the sugar or other ma terial off the screen. F ig; 7 shows the edges about tobe joined, but in this case illustrating a modified form of my invention. Fig. 8

shows the joint when completed in accordance with the modification shown in Fig. 7.

'In Fig. 3 the metal on one side of the joint has been shaded by light horizontal lines, while the metal on the other side of the joint has been shaded by light linesrunning at an angle, as it is thought that this shading will more clearly point out the limits of the metal and also the character of thejoint when completed.

Also it will be understood that the sheet shown in these drawings is perforated by a great number of very fine holes so it can act like a screen permitting the liquid to pass through same, but retaining .the solid material, such as sugar crystals, inside the screen during the centrifuging treatment. These perforations have been partially indicated in Fig. 1, but have been omitted from all other figures in the interest of clear-ness and simplification.

In equipping this screen or foraininous sheet with my new joint it is only necessary to slit the one edge 13 into a series of substantlally horizontal tongues b, the same being practically contiguous with each other,

and to form near the other edge A a slot a for each of the tongues 6, these slots a being slanted with reference to a vertical direction.

Broadly speaking there was of course no invention in merely using tongues along the one edge and some sort of slots along the other edge, as tongues and slots are an extremely old and primitive fastening expedient wherever it is desired to more or less join together two overlapping surfaces, but by the particular idea of'slanting the slots a in the manner indicated I have brought forth a joint that has a new and particularly useful advantage in connection with these centrifugal screens.

As indicated in Figs. 2, 3, and. 1, each of the tongues Z) needmerely be pushed through the slanted slot ct provided for it and the joint is complete, and has the appearance shown in Figs. 3 and at. In doing this the tongues are inserted through the slots from the inside of the cylinder outwardly, which leaves the inside where the sugar and other material is accumulated. practically smooth as the tongues are all on the outside of the,

bunchy on account of the several thicknesses of metal which this interweaving of the edges gives, which is rendered more-objectionable in view of the tendency of the metal to resist flattening or smoothing out of the oppositely directed curvatures which this interweaving action produces on the tongues.

My tongues however receive no such opposite curvatures in respect to each other, as they are all treated alike. and are merely pushed straight through the opposite slots, which involves no interweaving action and consequently results in a very flat thin oint that can be easily smoothed out to a condition of no appreciable thickness overthe single layer of metal on either side of the joint. In fact it is practically unnecessary to attempt any such smoothing, as neither the tongues on the one side, nor the edge with the slots .on the other side, are bent in making the connection, with the result that the joint is not accompanied with the bunchiness that characterizes other joints.

1 will now describe the excellent manner in which this joint is adapted to co-operate with the dischargin shoe.

Figs. 5 and 6 indicate the discharging shoe at 0, and as is well known the sharp tip or edge of this shoe is pressed against .the screen by the impact of the sugar wall d, as the sugar revolves with the screen and basket in direction of arrow 1 and encounters the shoe 0 which is mechanically held in the approximate position shown in Fig. 6.

As the sugar is cut out from the upper portion of the basket, the shoe is mechanically lowered to continue the cutting action, this lowering being accomplished by well known mechanisms known as dischargers which need not be described here as they have no special connection with this invention.

Fig. 5 however, by means of arrow 1, indicates the circumferential rotation of the screen, and by means of arrow 2 indicates arrow 3 is more or less variable also, but

the fact that it is inclined somewhat as indicated in Fig. 5 is obvious from the conditions mentioned.

lVith this established, attention is now directed to Fig. 3 which shows the joint on a suiiiciently large scale so that the action of he discharging tip in passing over it can be bestunderstood. Arrow 3, though probably excessively inclined, is applied to this figure to indicate the course of the discharging shoe over the joint.

' As the sharp tip of the shoe moves along the arrow 3 it will be seen never to encounter an upstanding edge. as all the edges encountered run from higher surfaces on to lower surfaces. which is the ideal condition, as no tearing or cutting of any sort can then occur between the screen at the joint-and the sharp tip of the discharger as it moves over it. Taking any particular slot and tongue in Fig. 3, it will be seen that a member moving approximately in direction of arrow 3 will run off the metal a on to tongue I), and again off the metal I) at the lower edge of the tongue on to the metal a, and in due course again off the metal a; of the next lower slot on to the tongue 1) adjacent thereto, and in each of these cases the motion was always from a higher surface to a lower surface which illustrates the point I am making that no upstanding edge is encountered in passing over my joint in a downward direction, or in one circumferential direction, or in any resultant direction comprising a combination of these two. From what has already been stated it is clear that this is the ideal arrangement in view of the clownward and crosswise direction in which the discharging shoe actually traverses the joint.

In conclusion, it may be fairly stated that the advantages hereinbefore stated, i. e., the advantage of an unusually thin fiat joint, and also the advantage of unusually good adaptation to the passage of the discharger shoe over the joint, are both obtained largely by my idea of slanting the slot-s with reference to a vertical direction, and providing such a slot for practically every tongue.

Of course my invention can be applied with more or less modification as illustrated in Figs. 7 and 8, which has the advantage of making the slotted edge a little stronger, and no doubt no serious difficulty would be encountered if any one endeavored to apply my invention by making small modifications such as omitting a small number of the tongues, or perhaps a small number of the slots, or perhaps by failing to insert a small number of the tongues in the slots, but in the main the form which I have illustrated and described is the best mode in which I prefer to make and apply this invention.

I claim.

1. A centrifugal screen comprising a foraminous sheet adapted to be bent substantially into a cylinder, the edges of said foraminous sheet being held together by tongues formed along one edge, and by slots formed adjacent the other edge, the slots being slanted with reference to the axis of said cylinder.

2. A centrifugal screen comprising a foraminous sheet adapted to be bent substantially into a cylinder, the edges of said foraminous sheet being held together by tongues formed along one edge, and slots formed near the other edge, the slots being slanted with reference to a vertical direction, and the tongues being inserted through said slanted slots from the inside of the foraminous cylinder outwardly so as to leave the inside of the cylinderv substantially smooth.

3. A centrifugal screen comprising a foraminous sheet adapted to be bent substantially into a cylinder, the edges of said foraminous sheet being held together by tongues formed along one edge, and slanted slots near the other edge, the tongues being substantially contiguous to each other and formed by slits extending substantially horizontally along the metal sheet, and said slots being slanted with reference to a vertical direction. substantially all the tongues being inserted through said slanted slots from the inside of the cylinder outwardly so as to leave the inside of the cylinder substantially smooth.

4. A centrifugal screen comprising a foraminous sheet adapted to be bent into a cylinder, the edges of said sheet being held together by tongues on the one edge and slanted slots on the other edge, there being a slot for substantially every tongue, the said slots being slanted with reference to a vertical direction, and substantially all the tongues being inserted through said slanted slots from the inside of the cylinder outwardly so as to leave the inside of the cylinder substantially smooth.

5. A centrifugal screen comprising a foraminous sheet adapted to be bent substantially into a cylinder, one edge of said sheet being slit into a series of substantially horizontal contiguous tongues, and the opposite edge of said sheet having a slot for each of said tongues, the said slots and tongues being adapted to form a joint, the said slots being slanted with reference to a normal vertical direction, and each tongue being passed through one of said slanted slots from the inside of the cylinder outwardly so as to leave no upstanding edge that could impede a movement in a downward direction or in one circumferential direction across the joint.

Signed at Denver, in the county of Denver and State of Colorado, this 26th day of March, 1923.

ROBERT ALEXANDER STEPS.

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