US3123557A

US3123557A - Centrifugal machine basket

Info

Publication number: US3123557A
Authority: US
Publication date: 1964-03-03
Anticipated expiration: 1981-03-03

Description

March 3, 1964 Filed Sept. 8, 1959 FIG.

SYRUP A. H. M PHEE ETAL 3 Sheets-Sheet 1 F A/R WASH SYRUP SUGAR ATTORNEY March 3, 1964 A. H. MCPHEE ETAL 7 CENTRIFUGAL MACHINE BASKET Filed Sept. 8, 1959 3 Sheets-Sheet 2 FIG. 2

FIG. 3 L

ALEXANDER H MC PHEE moms H. REID 4 I. Map

A TTORNEV March 3, 1964 A. H. MCPHEE ETAL 3,123,557

CENTRIFUGAL MACHINE BASKET F/G. 4 L

FIG. 5

FIG. 6

ALEXANDER H. MC PHEE WVENTORS moms H. REID A TTORNEV United States Patent 3,123,557 CENTRIFUGAL MACHINE BASKET Alexander H. Melhee, Piandome Heights, and ThomasH.

Reid, Brooklyn, N.Y., assignors to Hepworth Mach ne Company, Inc, Long Island City, N.Y., a corporation of New York Filed Sept. 8, 1959, Ser. No. 83%,046 2 Claims. (Cl. 210-382) This invention relates to centrifugal machines of the continuous type and more specifically, in a preferred aspect thereof, to basket structures therefor. 'This application is a continuation-in-part of application Serial No. 686,489, filed September 26, 1957, and now abandoned, by the present inventors.

It is an object of this invention to simplify, strengthen, and improve baskets used in non-cyclic, constant speed centrifugal machines adapted, for example, for sugar refining.

Non-cyclic, constant speed centrifugals (also known as continuous centrifugals) have been used heretofore in the refining of sugar and in similar applications. in one such type, an apertured frtrsto-conical basket has continuously applied thereto a fiow of sugar massecuite or magma. The rotation of the basket results in centrifugal force which has the effect of causing the syrup or molasses to flow through the perforations in the side of the basket and of causing the purged sugar crystals to be discharged from the open end of the basket.

In one common type of basket used in sugar centrifugal machines of the continuous type, an outer shell has a multiplicity of perforations therein. Within this shell are one or more mesh members acting to screen the sugar. In one particular arrangement of the prior art, both fine and coarse mesh sieves are used. flhe mesh in the fine screen is made fine enough to retain the sugar crystals in the basket, but it permits the escape of syrup toward the outer shell. The second, coarser, screen between the fine screen and the outer shell is used to hold the fine mesh screen away from the outer shell and thus prevent sugar grains from gathering on the inside of the shell (since the spaces between perforations of the shell are much larger than the interstices of the fine mesh screen). In this arrangement the outer shell is the strength member in the combination.

The type of basket just described follows very closely the design of the baskets for cyclic centrifugals. The speed of the latter is much higher than that of continuous centrifugals, and the sugar wall is much thicker. Both of these factors cause a much greater centrifugal force tending to push outward against the basket of the cyclic centrifugal than is the case of the continuous one.

The present invention is based on the realization that the much lower outward force in the baskets of continuous centrifugals makes possible a greatly simplified, yet very strong, type of basket. in a preferred and illustrative embodiment of the present invention, the key member of the basket combination is a frusto-conioally shaped, open-work basket having large openings therein (each many, many times larger than the size of a sugar grain and also much larger than the apertures in the outer shells of the centrifugal machines of the prior art). The open-work basket comprises a hub member, an outer ring of greater diameter than the hub member and a plurality of longitudinally-extending ribs connected between the hub and the ring. These ribs are of rectangular crosssection and are placed so that the larger dimension thereof (which is at least four times the shorter dimension thereof) is in a radial direction. Outside the ribs, for strength and rigidity, are welded, or otherwise secured, a plurality of circular rings or hoops. Inside the "ice basket, and in direct contact with the faces of the ribs having the shorter cross-sectional dimension, is a single, mesh sieve or screen, having apertures sufficiently small to trap the sugar grains. Thus, the open-work basket serves a double function: (1) it is the strength member of the basket combination, and (2). it fulfills the spacer function of the coarse screen of prior art devices.

if it isdesired to make the spaces in the supporting structure somewhat equal even though the radius of the basket increases from one end to the other, various arrangements can he provided. In one of them, the rib members are made wider at the larger diameter end than at the smaller end. In another arrangement, some of the ribs are used only at the larger diameter end of the basket.

By inclining the ribs to a radial line, the air flow within the basket is increased.

The invention will be more readily understood by referring to the following description taken in connection with the accompanying drawings forming a part thereof, in which:

FIG. 1 is a vertical cross-sectional view of a continuously-fed sugar centrifugal machine embodying a basket in accordance with the invention, some of the specific details of the basket structure being omitted for simplicity in the drawing:

FIG. 2 is a vertical elevation view, with portions in cross-section, of the basket in FIG. 1 showing more structural details;

FIG. 3 is a partial cross-sectional view taken in a plane along line 3-3 in FIG. 2;

FIG. 4 is a schematic representation of the arrangement of ribs in the basket of FIG. 2;

FIG. 5 is a schematic representation of a modified arrangement of ribs in the basket;

FIG. 6 shows another rib arrangement; and

FIG. 7 shows still another rib arrangement in which each rib is inclined to a radial line to promote air circulation.

Referring more specifically to the drawings, FIG. 1 shows, by way of example for purposes of illustration, a sugar centrifugal machine it) of the continuous type adapted to use a basket ll in accordance with the invention.

The centrifugal machine 10 comprises a first stationary housing 12, a second stationary housing 13, a third stationary housing 14, the basket 11 rotating within and be tween these housings, means including a revolving screw 15, an accelerating cone 16, and a distributing cone 17 for supplying magma continuously to the inside of the basket 11, and means (not shown completely in order to simplify the drawings) for rotating the screw, the accelerating and distributing cones, and the basket.

Ma-ssecuite is applied to the right hand end of the screw 15 from a suitable mixer pan. As the screw is revolved, the magma is conveyed toward the left, it being maintained all the while at an even temperature by warming fluid applied to the pipe 18 surrounding the screw. The accelerating cone 16 is rotated at any convenient speed by the shaft 19. As the massecuite hits the cone 16, it is gradually accelerated in speed and it is delivered, as shown by the arrows in 'FIG. 1, to the inside of the distributing cone 17. The stream moves outward, to the left in FIG. 1, along the inside of the distributing core 17. Then it passes into the basket 11 where it is further accelerated in speed due to the increasing centrifugal force caused by the increasing diameter of the basket from left to right.

In the washing zone of the basket 11, wash water is applied from spray members 20 connected to water pipes 21. Air is supplied from chamber 22 connected to suit- 3 able inlet pipes to assist the passage of syrup through the interstices of the basket 11 into the chambers 12 andlS. In order to induce more pressure, vanes 23 and 24 are attached to the outside of the basket.

While the syrup is on the left of barrier 25 on the outside of the basket 11, the green syrup flows into the housing 12. While the massecuite is in the washing zone adjacent the sprays 2%), the wash syrup flows into the housing 13. The sugar grains flow out the end of the basket 11 into the housing 14.

Reference will now be made to FIGS. 2 and 3 which show a basket 11 in accordance with the invention which is peculiarly adapted for use in the continuous centrifugal machine just described briefly. The basket 11 comprises a metal end or hub member 30 to which are attached a multiplicity of spaced metal rib members 31 extending outwardly in frusto-conical fashion to an end member 32. The member 31 can be screwed, riveted or welded (preferably the latter) to the member 363. Surrounding the ribs and welded, or otherwise secured to them, are a plurality of metal tension rings 33. These rings are necessary to absorb the circumferential stresses induced in the basket by the centrifugal force developed at high speeds. Within the confines of the shell produced by the ribs 31 and the rings 33 is placed a single, mesh sieve or screen 34, the interstices of which are much smaller than are the spaces 35 between ribs 31 and rings 33. By way of example, the screen 34 may be a stainless steel sheet about .030 inch thick with perforations A inch each spaced inch apart. Thus no sugar grains will lodge between screen '34 andthe outer shell formed by the ribs and rings. This shell is structurally very strong and is simple to construct. The wide part of the cross-section of each rib 31 is of the order of four or five, or even more, times the narrow part thereof. The narrow part is in direct contact with the screen 34 and does not obstruct many holes in the screen 34'while the wide part imparts great strength to the basket. The wide parts also serve as the vanes of an impeller which tends to induce the flow of air through the screen 34. Due to the lower centrifugal force in continuous centrifugals running at about 600 r.p.m., the screen 34 will not be forced into the spaces 35 (as might be the case if the much larger centrifugal force of cyclical centrifuges were acting on it).

The rib-work may take various forms. For example, 1 16.4 shows an arrangement in which all ribs 31 have the same width or thickness from one endof the basket to the other. This makes larger openings at the right end of the basket than at the left. If desired to minimize this change in size of opening, the ribs 31 in FIG. can be of increasing width, the larger width being toward the larger end of the basket. Another way to reduce the size of the openings at the large end of the basket 11 is to provide a plurality of intermediate ribs 31A extending from, for example, the center line of the basket, to the outer end, as shown in PIG. 6. Obviously, a variety of other rib arrangements are possible.

The ribs 31 can have still another function. If they are arranged in such a way that they are inclined to radial lines 36 from the center of the basket (as shown in FIG. 7), they induce a reduced pressure or partial vacuum on the outside of the screen; hence the air circulation and thus the efliciency of the basket are improved.

The baskets of this invention can have of the order of %more open area than do conventional baskets of the prior art While the shell itself is even stronger due to the ring and rib construction.

Obviously, various changes can be made in the embodiments described herein without departing from the spirit of the invention.

What is claimed is:

1. A composite basket structure for a continuous sugar centrifugal machine comprising an open-work basket cornprising a hub member, an--end ring member of greater diameter than the hub member, a multiplicity of spaced rib members between the hub member and the end ring member, each of said rib members having a rectangular cross-section in which the short dimension thereof is no larger than a fourth of its long dimension, said rib membersextending longitudinally of said container and being spaced in such a manner that they form an outer basket of frusto-conical shape, and a plurality of spaced ring members surrounding the rib members in the space between said hub member and said end ring member, and a thin metallic container of frusto-conical shape having a multiplicity of perforations therein of a size to prevent the passage of sugar grain therethrough and being much smaller than the space between rib members and the space between ring members, said container being within said open-Work basket in intimate contact with the short dimension of each of said ribs, some of said rib members extending only a portion of the overall distance between the larger end of said frusto-conical container and the smaller end thereof.

2. A composite basket structure for a continuous sugar centrifugal machine comprising an open-work basket comprising a' hub member, an end ring member of greater diameter than the hub member, a multiplicity of spaced rib members between the hub member and the end ring member, each of said rib members having a rectangular cross-section in which the short dimension thereof is no larger than a fourth of its long dimension, said rib members extending longitudinally of said container and being spaced in such a manner that they form an outer basket of frusto-conical shape, and a plurality of spaced ring members surrounding the rib members in the space between said hub member and said end ring member, and a thin metallic container of frusto-conical shape having a multiplicity of perforations therein of a size to prevent thepassage of sugar grains therethrough and being much smaller than the space between rib members and the space between ring members, said container being within said open-work basket in intimate contact with the short'dimension of each of said ribs, some of said rib members extending from the larger end of said frusto-conical container to points between the larger and smaller ends thereof.

References Cited in the file of this patent UNITED STATES PATENTS 1,127,502 Paradine Feb. 9, 1915 1,832,269 Webb NOV. 17, 1931 1,902,982 Abbott Mar. 28, 1933 2,251,678 Holt Aug. 5, 1941 2,516,963 Derbenwick et al Aug. 1, 1950 2,883,054 Sanchez Apr. 21, 1959

Claims

1. A COMPOSITE BASKET STRUCTURE FOR A CONTINUOUS SUGAR CENTRIFUGAL MACHINE COMPRISING AN OPEN-WORK BASKET COMPRISING A HUB MEMBER, AN END RING MEMBER OF GREATER DIAMETER THAN THE HUB MEMBER, A MULTIPLICITY OF SPACED RIB MEMBERS BETWEEN THE HUB MEMBER AND THE END RING MEMBER, EACH OF SAID RIB MEMBERS HAVING A RECTANGULAR CROSS-SECTION IN WHICH THE SHORT DIMENSION THEREOF IS NO LARGER THAN A FOURTH OF ITS LONG DIMENSION, SAID RIB MEMBERS EXTENDING LONGITUDINALLY OF SAID CONTAINER AND BEING SPACED IN SUCH A MANNER THAT THEY FORM AN OUTER BASKET OF FRUSTO-CONICAL SHAPE, AND A PLURALITY OF SPACED RING MEMBERS SURROUNDING THE RIB MEMBERS IN THE SPACE BETWEEN SAID HUB MEMBER AND SAID END RING MEMBER, AND A THIN METALLIC CONTAINER OF FRUSTO-CONICAL SHAPE HAVING A MULTIPLICITY OF PERFORATIONS THEREIN OF A SIZE TO PREVENT THE PASSAGE OF SUGAR GRAIN THERETHROUGH AND BEING MUCH SMALLER THAN THE SPACE BETWEEN RIB MEMBERS AND THE SPACE BETWEEN RING MEMBERS, SAID CONTAINER BEING WITHIN SAID OPEN-WORK BASKET IN INTIMATE CONTACT WITH THE SHORT DIMENSION OF EACH OF SAID RIBS, SOME OF SAID RIB MEMBERS EXTENDING ONLY A PORTION OF THE OVERALL DISTANCE BETWEEN THE LARGER END OF SAID FRUSTO-CONICAL CONTAINER AND THE SMALLER END THEREOF.