US2461773A

US2461773A - Balancing centrifugal machine

Info

Publication number: US2461773A
Application number: US598811A
Authority: US
Inventors: Thomas H Reid
Original assignee: Individual
Current assignee: Individual
Priority date: 1945-06-11
Filing date: 1945-06-11
Publication date: 1949-02-15
Anticipated expiration: 1966-02-15

Description

Feb. 15, 1949. T. H. REID 2,461,773

BALANCING CENTRIFUGAL MACHINE Filed June 11, 1945 $0M! M5744 2511/01/50 50M! All-Z44 REMOVED Fae Mum-m5 PuzPoSi-S F02 amwa/va puefiosas JNVEN TOR. 7/70/1445 A. 25/0 Patented Feb. 15, 1949 UNITED STATES ATNT OFFICE 1 Claim.

This invention relates to the balancing of rotating devices and more specifically to the balancingof centrifugal machines used in the manufacture of sugar.

An object of this invention is to provide novel and improved means for balancing the rotating baskets of sugar centrifugal machines.

In modern sugar refinery practice, the centrifugal machines employed for purgin crystalline sugar of mother liquor or the like are in substantially continual operation. The basket'of each machine is loaded with a charge of sugar magma or massecuite, accelerated rapidly to high speed, and, after a few minutes, rapidly braked and unloaded in preparation for the next charge. It is very important that these baskets be very accurately balanced or the centrifugal force acting on the unbalanced mass will in time cause the machine to be torn to pieces. In low speed centrifugal machines, this balancing can be accomplished by soldering or welding small pieces of metal on the periphery of the basket (usually between adjacent reinforcing hoops surrounding the basket). In a high speed machine, however, such as that which employs a basket of the type disclosed in Patent 2,315,980 issued April 6, 1943 to Charles A. Olcott, for example, this means of balancing cannot be used as the small bits of metal fly off at the high speed. The present invention relates to means for baancing high speed sugar centrifugal machines which does not involve addin extra material.

In accordance with a specific illustrative embodiment ofthe present invention, this balancing is attained by the-enlargement of at least the outer ends of certain of the apertures in the basket through which the liquids are ejected. The apertures in a basket are usually arranged in rings, with the holes in alternate rings preferably staggered so that the entire wall of the basket is covered with perforations. In the basket disclosed in the above-mentioned Olcott patent, external circumferential grooves are cut in the basket wall, each groove overlying and passing through one of the rings of holes. In order to provide maximum strength near the top and bottom of the basket where the shearin stresses are greatest, at least one of the rings of holes nearest the respective top and bottom basket heads is left ungrooved. These latter holes are usually flared as it has been found that centrifuged ma- It has been discovered that small bits of metal can be easily removed from certain ones of the flared holes in the upper and lower parts of the centrifugal wall, preferably by countersinking-or increasing the flare, and that this removal of certain weight on one side or one portion of the basket can be used to effect balancing of the centrifugal ma chine. In cases where the holes are not flared, either countersinking or reaming can be used.

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

Fig. 1 is an elevation view, partly in cross-section, of a portion of a sugar centrifugal showing a basket which is balanced in accordance with the invention;

Fig. 2 is a horizontal cross-sectional view of a portion of the periphery of the basket of Fig. 1 showing certain holes in the basket countersunk to remove metal for balancing purposes; and

Fig. 3 is a horizontal cross-sectional view of a portion or" the periphery of the basket of Fig. 1 showing certain holes in the basket reamed to remove metal for balancing purposes.

Referrin more specifically to the drawing, Fig. 1 shows, by way of example for illustrative purposes, a sugar centrifugal machine I53 which is balanced in accordance with the invention. The machine it! includes a vertically arranged spindle ll driven by any suitable means (not shown), such as by a separate hydrauic or electric motor or by pulleys or gearing from a source of power common to a plurality of such centrifugal machines, and a basket it supported from the spin dle and adapted'to turn therewith within a casing it. The casing is so shaped and arranged in well known manner that mother liquor, wash .water and the like expelled through the foraminate wall of the basket flows down the inner face or curb of the easing into an annular trough M where it is collected and drawn off.

.The basket 12 comprises a cylindrical wall I5, an upper head iii comprising an'integral annular flange and a corresponding lower head I? of similar construction. This integral structure is preferably forged from a single ierced billet of steel and machined to final dimensions. To the lower head H is welded a steel hub it that is fitted to spindle H and firmly fastened thereto by any suitable means. The welded joint 19 lies in a region where the stresses incident to high speed operation are comparatively small.

The cylindrical wall l5 of the basket l2 has numerous holes 20 for the escape of centrifuged molasses or the like. These are arranged in a multiplicity of circumferential rings of holes with the holes in alternate rings preferably staggered as in the arrangement shown in the drawing, so that the entire wall is pierced by perforations. As a specific instance of practice which may be borne in mind for better understanding of the invention, the inside diameter of the basket may be forty inches, its height twenty-four inches, and the holes one-quarter inch in. diameter where the metal is to be removed. By gradually enlarging certain of the holes 22 and by rotating spaced apart one inch on centers in each ring with the rings one inch apart. As disclosed in the above-mentioned Olcott patent and as shown in the drawing, external circumferential grooves 2| are cut in the basket wall, each groove overlying and passing through one of the rings of holes. tangular cross-section but rounded at the bottom The grooves 2| are preferably of. recor at the bottom corners, and the width of each forth above,,the groove width may be one quarter of: an inch. As pointed out in the Olcott patent,-'the portions in the rings between the holes contribute very little to holding the basket together. and hence they are reduced in vmass (by grooving them) and therefore develop less cen- Y trifugal force to burden adjoining portions without a corresponding loss in strength. The present-invention, however, is preferably not concerned with the apertures20 in the grooved rings 2! but in the apertures 22 which are arranged in ungrooved rings in the upper and lower portions of the basket wall. These portions of the wall are left ungrooved so that shearing forces, which are greatest at top and bottom, can be better resisted. These holes 22' may already be tapered or countersunk as shown in Fig. 2 and small additional bits of metal are removed from certain ones of the holes 22 by countersinkingwhen it is determined that the mass on the side nearest these certain holes is larger than it should be for perfect balancing. This can be determined by rotating the basket at high speeds on a machine called a dynamic balancer several makes of which are on the market.

The holes 22 to be enlarged are in general only: atone side of the basket, at either the top or. the bottom. This is caused by the fact that slight errors in machining or density of the metal generally -result in the basket being heavier on one side .than on the other (which would tend to make the machine run out of balance were it not corrected.) In dynamic balancing it is necesside. In short, tobalance the basket, metal must beremoved at the proper, place and in the proper amounts. The

a dynamic balancer." indicates,

the machine after each enlargement, it can be determined when the machine is perfectly balanced.

As an alternative to countersinking, the outer ends of certain holes 22 can be reamed out, as shown in Fig. 3. This means'can be used either with tapered or untapered holes.

The means of "balancing describedabove has the advantages that (1) there are no parts to fiy off at high speeds, (2) no new holes need be drilled, use being made of holes already having a function,-and-y(3)- the enlargement of the holes takes very little time and is simple and inexpens1ve.--

It will .be, apparent that although the present invention has been described with reference to itspreferred embodiments it will be understood that it is capable of embodiment, in a variety of;:other :fo'rms;.within the. spirit and scope ofthe claim, and that the specific proportions vand; dimensions hereinbefore set forth are illustrative and not limitative. While it is preferredithat the 1 apertures which are enlarged; for. balancing purposes .be near :the vertical extremities '(topzand bottom) of the basket, it will be readily apparent .J.

that'they need, not be solocated;

What issclaimed is:.

A basket for. a sugar centrifugal; which is nor-- mal-ly slightly but of balance comprising a bottom'memberyanuppenhead member and. a'cylindrical wall therebetweem'said wall having a cen- A tralportion. with la: plurality of tgroovedrings therearoundand :upper. and lower portions adjacent the head member and bottom: member, re-

the said basket is balanced, said certain 'ones be-' ing .on'the side :of said basket which would be the heavy side'when it is rotating were it not for:

the said-removal of metal';

THOMAS H. REID.

REFERENCES CITED The following references are of record in the file 'of this patent:

UNITED STATES PATENTS Number Name Date 1,189,726' Nyberg July 4, 1916'; 1,195,074 Ohlsen Aug915, 1916. 2,068,636 Roberts Jan. 19, 1937 2,315,980 Olcott Apr. '6, 1943';