US399616A - Screen for bolting flour - Google Patents

Description

{No Model.)

0. P. HURFORD.

SCREEN FOR BOLTING FLOUR. No. 399,616. Patent-ed Mar. 12, 1889.

HM 1 I B E 2 5 i X Fig.1

WITNESS-ES: v IIVVEIVIORI d; I QZgvcrl?Hmjoj-d ATTORNEY. I

Miran Starts Parasr Fries.

oLivER r. neurons, or our uico, 'rtrmors.

senses-i roe sorrme FLOUR.

SFECIFICATION forming part of Letters Patent No. 399,616, dated March 12, 1889.

Application filed April 5,1888. Serial No. 269,700. (No as.)

T 0 all whom it may concern:

Be it known that I, OLIVER P. HURFORD, of Chicago, in the county of. Cook and State of Illinois, have invented a new and useful Improvement in Screens for Bolting Flour; and

I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, making part of this specification.

My invention relates to that class of screening-machines (either flat or tubular in form) in which the screening-surface is located in,

particles or grades of the flour boltin -surfaces composed of a woven silk fabric. the use ef' such wire-Woven fabric (employed mostly in. those screens familiarly known as scalpers more or less difficulty arises from the fact that in 'practicaloperation this ordinary woven-wire fabric is of such a struct ural character that not only are pocket-like recesses (of comparatively great capacity) afforded within which numerous collections of the small particles of the material being treated accumulate and pack, thus more or less clogging up the meshes of the screen and impeding the flowing over its surface freely, and the passage through its meshes easily of the particles of material which should readily pass through the screen, but, furthermore,

(the structural character of this ordinary wire screen) is such that its innumerable abrupt projections so forcibly oppose the action of the brushing device (that must be employed in all such screening contrivances) as to very rapidly wear out the brush. Again, a thorough cleaning off of (or cleaning out of the meshes of) the screenin -surface, or, in other words;a perfect clearance of the meshes of i the screening-surface, is rendered difiicult, if

not impracticable, by reason o f the constant.

presence of the accumulated flour in the pocket-like recesses just above referred to,

which flour tends to pasteoier the meshes during the brushing operation, and to thus partially destroy the eificiency of the screen.

I propose by my improvement to provide for use a woven-wire screening-surface which shall be comparatively free from the objections just explained as being peculiar to such wire screens as have been heretofore made and used; and to this main end and object my invention may be said to consist, essentially, in a wire-woven screening-surface having all the projecting portions or points of the interlaced wires flattened, (in any suitable manner, preferably by subjecting the ordinary woven-wire fabric to a rolling or calendering opcration,-) so as to render the operative surface of the screen comparatively smooth, and so as to also very materially lesence to the accompanying drawings, which form a part of this specificatiomand in which I have shown my invention carried into effect in two (of the various well known) forms of screening-machine to which it is applicable.

In the drawings, Figure 1 is a side view of an ordinary form of cylindrical scalpel or screening -'machinc such as now commonly used in liouring-mills, but embodying my improvement.

ingmore particularly the relative arrangement with the cylinder of one of the usual forms of brushing devices and illustrating the presence of the material that is fed into, re-

tained in, and passed through the screeningcylinder. Fig. 3 is a longitudinal perspectiy e of so much of a machine provided witlra iiat screening-surface as it is necessary to show for the purpose of exhibiting and explaining the application of my improvement to this 9 Fig. 2 is a vertical cross-section of the cylinder at the line a: :1 of Fig. 1, showand 3, in which figures, however, the scale is too small to permit anyintelligible illustration of the precise structure of said woven fabric. Fig.6 is a skeleton. or sort of diagrammatical View showing, on an exaggerated scale and in cross section, portion of a screen made in 'the old-fashioned way and illustrating how the flour is apt to lodge within the small pocket-like recesses of the woven-wire fabric. Fig. 7 is a similar view of portion of a screen such'as seen at Figs. '1, 2, and 3, made according'to my invention and illustrating the action of such improved screening device.

Each of the sectional views 6 and '7 .is drawn on a plane of section passing adjacent to one of the, strands of the woven-wire fabric of Y which the screen is (in each case) supposed to .be-made, andlimall the views in which arrows are seen they indicate the directions of v movement of the screens,a nd also of the material being treated.

\Vherever the same part is shown in differentfigures it will be found designated by the same letter.

In the machine shown at'Figs l and 2, A is the screening-cylinder, constr'ucted,'mounted, and operating in the usual and well-known manner, except that its screening-surface is composed of a diiferent sort of woven-wire fabric, and Bis the brushing device, arranged and operating in one of the well-known ways.

In Fig. 3'the flat screen 0 is constructed, mounted, and suitably agitated with'a sort of reciprocatory motion, all in the usual wellknown manner; except that the woven-wire fabric composing the screening-surface is,

I like that of the cylindrical machine shown, of

a difierent structural character.

In both forms of machine shown as embodying my invention the screening surface (marked A in one case and G in the other) is made of a fabric that is firstywoven of wire strands of equal size and exactly similar to the fabric heretofore used, and that is subsequently subjected to pressure superficially,

(preferably by passing the fabricated material between compressing-rollers,) so as to upset the stock of and flatten out (so to speak) -all the abruptly-projecting portions or all the superficial protuberances of the fabric at the localities where the interlaced metallic strands overlie (or undei'lie) each other. In other words, the metallic woven fabric of which these screening-surfaces are composed is one which results from taking the fine woven-wire.

abric, heretofore usually employed in the construction of screens and subjecting it to superficial pressure (preferably by passing it between compressing-rolls) in such manner and to such extent as to change its condition from that shown at Figs. at and 6 (which show the old-fashioned fabric) to that seen at Figs. .5 and 7, which show the fabric used in my improved machine; and by a reference to and comparison of what is'shown, respectively, in Figs. 4 and 6 and 5 and 7 it will be readilyseen that while in the fabric heretofore employed in the construction of screening-machines the I multitudinous abrupt projections e (see Figs. land 6) present serious obstruction to a free tumbling and sliding movement over the screening-surface of the particles designedto be passed through'the meshes of the screen, this source of obstruction to a free movementof these particles over the said screening-surface has been in a great degree removed in the fabric used in my improved machines,

since'by the flattening down of these pro jections, as seen at f, (see Figs. 5 and 7,) the metallic superfices of the screen have been rendered smoother. In other words, by thus flattening out (or mashing down) all the abrupt projections, as shown at Figs. 5 and 7, the asperities of the old-fashioned screening surface have been materially softened or removed, so that the light and fine particles of the mass of the material supported upon and agitated on the screening-surface of the improved machine will move oversaid surface with more freedom, and hence be afforded more opportunities topass through or greater in finding their way through the meshes of the screen; Furthermore, in a machine provided with the kind of fabric shown at Figs. 5 and 7, as both surfaces of the fabric are thus smoothed, so to s'peak, the brush employed to keep'the screen clear or clean (whether applied to one or the other of the surfaces of the woven 'fabric) will not be abraded by frictional contactwith the screen nearly as much, and consequently will not be worn ,out (or have its eificiency impaired) nearly as soon as the brushing devices used in machines provided with the old-fashioned kind of metallic screening device.

'The comparison of this new kind of flourscreening machine fabric with the old-fashioned sort also shows that while in the kind seen at Figs. 4 and 6 the interstices or receptacle-like recesses (seen at g) are of suflicient capacity to retain considerable quantities of the flour, these recesses in the kind of fabric shown at Figs. 5 and 7 are, as shown at also reduced in size and in their capacity to retain portions of the fine particles of the material being treated as to practically overcome a heretofore serious difficultyviz., the

rapid accumulation in these interstices of sufficient quantities of the flour to not only partially clog the meshes, and thus impair their function, but to also cause the pasting IIO over of the screening-surface by the action of the brush on these accumulationsof flour.

stock in-roller milling the common wovenwire cloth rasps orgrates oif a large portion of fiuif and fine middlings, which go into the flour to discolorit and increase the proportion of the lower or less valuable grades.

Then in grading the nliddlings, after having.

consequently thrown to the dust-room, at a been scalped off, the smooth-surfaced .or flattened wire-cloth does not wear or flour the middlings, in consequence of which a large portion of flour is sent to the purifiers, and

' great loss to the miller, as does the old-fashioned rough-surfaced cloth. 7

By the use of the flattened or smoother snrfacedwoven-wire screening-surface the machine is adapted to the grading oftheffiner qualities of middlings, which heretofore could he done only on a kind of silkcloth known as grits-gauze at a heavy expense,,asy-the sharp middlings cut out the grits-gauze very rapidly, rendering itnece'ssary to frequently :replace it. The smooth-surfaced wire-cloth does the work equally as well-and will last a year.

'Among other and minorjadvantages to the screening-machine resulting from the-use therein of a bolting or screening wire fabric of the novelcharacter herein shown and described may be mentioned -tl1 e; ironing out (so to'speak) of all the pnckers or'superficial wave-like irregularities,-i which always exist in fine woven-wire fabrics as they comefrom the weaving-machine, whereby. a' fabric for the screening-surface (whether flat or curved) is provided for usethat maybe formed into I either aperfect plain or a perfect curve, so

' that the brushing device will properly sweep over every point throughont the whole surface designed to be acted uponby such brush.

Furthermorain the use of such a metallic fabric, for the screen the meshes may be made smaller and-hence ,ajfiner wire screen can be employed (wherever this may be desirable) than could :possibly'be used in the construe tion of a wire screen as heretofore made.

7 Having now so fully explained the construetion and operation .of my. improved flourscreening machine that those skilled in the art can readily understandand practice my invention, and wishing itito be understoodthat I do not claim, broadly, as anew manu facture, a flattened woven-wire fabric, such a fabric being old per 86', what 1110 claim as new, and desire to secure by Letters Patent,

15 .A linachine for screening. .-or bolting'fiour 'h'aving "screening-surface composed of a flattened woven-wire fabric, substantially as and for the purposes set forth.

In witnesswhereof I have hereunto set my hand this 30th day of March, 1888. 7

OLIVER -P., HURFORD.

In presence of E. A. T RNER,

W. P. SISSON.

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