BE636252A - - Google Patents

Description

       

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  "Rice polishing process"
The present invention relates to the polishing or bleaching of brown rice and includes a novel. method and a new polishing apparatus suitable in particular for carrying out the method.



   It is customary in practice to prepare brown rice for further polishing by removing dust, straw and other debris from the unhulled rice, which is then admitted into stone decorticators where the husks are removed as well. that part of the sound that adheres weakly. The husked brown rice is then polished in a machine comprising an envelope.

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 horizontal cylindrical lopper with perforations. The machine features a rapidly rotating inner rotor having a ribbed surface, which rubs the brown rice against the outer cylindrical casing to rub off the bran from the endoaper.



   The surface rubbing operation is performed normally under conditions of residence time and flow rate selected to provide a desired degree of removal of the outer layers of bran from the rice kernels. The polishing process is quite severe and smooths a significant proportion of the whole of the rice kernels into two or more fragments by a combination of factors such as shock, mechanical and thermal forces, and the heat generated. Brie results in a loss from an economic point of view, since broken rice has less value in the market than whole rice cakes.



   In a process of the present invention, brown rice is treated with a liquid bran softener and the bran is removed by polishing from the rice kernels in the presence of the softening agent. The softening of the bran located on the outside of the grains of brown rice decreases the degree of abrasion necessary to remove the bran from the grains, decreases the brie of the grains, decreases the increase in temperature at the during the polishing process to a certain hyphenation and allows smoother operation to be achieved.



   The starting material constituted by a brown sweetbread can be a raw rice husked and cleaned or

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 , unshelled rice that has been half boiled and dried before removing the husks.



   Either source of brown rice is satisfactory, although that from unhulled rice gives a better product than that from brown rice, which has been half-boiled enough to penetrate a medium. much of the bran layer in the endosperm.



   Any non-toxic and easily removable liquid material which has the property of wetting, dissolving and penetrating into the bran layers of rice grains and of being miscible with oils can be used as a bran softening agent. proteins and carbohydrates and attack the complex structure of the latter existing in said layers, except water.

   Starchy rice kernels are so easily affected, either by pure water or by water containing the small proportions of it which normally exist in domestic water supply pipes that it is impossible to soften the existing bran. on the rice with water to an extent which significantly improves the ease of polishing without forcing the rice to absorb moisture and thereby increasing the brio of the rice grains during the polishing process.



   The term "liquid sen softening agent" is used in the present application in a particular limited sense to exclude water, but to encompass non-polar liquid materials, such as highly refined mineral oils,

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 predominantly non-polar materials, such as higher fatty acids, esters of higher fatty acids and glycerol, glycol and polyglycol, and both polar and non-polar organic materials having a hydrophobic group and a hydrophilo group in the molecule, such as soaps, alcohol esters of sugar and higher fatty acids, amido compounds of higher fatty acids, glycols having three or more carbon atoms in the molecule and polyglycols,

   aqueous solutions of alkaline materials, which have a saponification effect on the fatty components and an aolubilization effect on certain protein components of bran, such as hydroxides and carbonates of ammonia and the alkali metals of aqueous solutions of neutral salts, which attack and make soluble certain proteins of the sound layer, such as chloruros and sulphates of ammonia and alkaline metals and dilute solutions of acids which are not toxic in weak proportions present, but which have the effect of attacking and solubilizing proteins, such as hydrochloric, sulfuric, phosphoric and citric acids.



   The effect of the aqueous solutions indicated above is quite distinct from the results obtained by using a similar amount of water. For example the addition of a small amount of 2 percent water for example to brown rice does not soften the bran to a very great extent and is accompanied by an increase in the water content of the sweetbread.

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 less to take great care during the addition. Addition of a similar amount of a 5% aqueous solution of hydrochloric acid has a very increased softening effect, due to the attack of proteins by the acid and the increased binding of water in it. swelling reactions of degraded protein materials.



   When polishing in the presence of solvent alum capable of extracting fatty components from the bran and from the seed, the bran softening agents may be materials which are soluble in the solvent and which are capable of being emulsified. in the solvent, unlike being really soluble therein, such as the aforementioned aqueous solutions. These materials usually tend to selectively wet the bran coating and be absorbed by it.

   However, the amount of these solutions or suspensions used should be limited to an amount insufficient to penetrate through the bran coating and to wet, swell or alter the color of the backing so that the softening agent wets. ble by water or soluble in water, and the water in which it is dissolved or suspended, are absorbed in the sound layer, excluding absorption below the sound layer. aleurone.



   Ammonium compounds are particularly advantageous since they can be easily and completely removed by heating during the subsequent finishing stages or by distributing them in

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 a system which solicits, when it is used, the anion molecular weight elovated this diaool before the solvent and the ammonium remaining in the water containing the deposit of non from which it is evaporated when the bran is recovered, the removes the solvent and dries it.
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  The cetera of glycerol and higher flraa acids can be used in the form of edible vegetable oils, such as rice oil. oil
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 mare, cottonseed oil, etc., as desired. When extractive polishing is used as described above, recycled rice oil or a solution of rice oil in a suitable solvent is a very satisfactory softening agent and is preferred because it is readily available substantially nana fresh.
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  In general, one dbit to use the ramol -'l ", Z" bonding of the oon layer in the proportions,, between 0.25 and 5.0 yard hundred by weight per ... -. : relative to the weight of rice; brown, These quantities apply ### $ 1,!; quent to the total amount of liquid softening agent # ', smoothing bran, including any medium in which: .'-.



    *, an active reagent is dissolved in order to obtain a correct distribution and wetting of the rice. When using mineral oil or undiluted vegetable oil, the amount of oil required is between about 0.25 and 1.0 percent, although an amount of between 2.0 and 5.0 percent a solution of the same oil in a suitable solvent may be advantageous depending on the degree of dilution.

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   Thus, for recycled rice oil this coaprious range between 2.0 and 5.0 percent would apply to the oil plus the residual solvent content.



   Alkalis forto pulleys, such as sodium and! potassiu, it is convenient to add
2 to 5 percent by weight of an aqueous solution containing about 1 percent to 5 percent of the active ingredient; for ammonia, 2 to 5 percent by weight of commercial ammonia should be used; for ammonium carbonates, 2 to 5 percent by weight of an aqueous solution containing up to 20 can of carbonate ammonium, as this material 0 evaporates readily in the final stages for salts, acids, surfactants, otc, from 25 percent of aqueous solutions or suspensions containing 0,

  1 to 20 percent of the reagent depending on its nature is advantageous. Although larger proportions can be used, no advantage is gained and excessive amounts of residue may remain in the product which, although not deleterious, may impart poor taste. Anyway, is it unnecessary to dry or otherwise remove the bran softener? . before a polishing stage and the polishing can be carried out in the presence of the bran softening agent.



   The polishing can be carried out without additional addition of liquid or it can be carried out in the presence of a solvent capable of removing the fatty components of the rice, bran and germ. In by name

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 Many practical applications, it is desirable to extract certain water soluble components from brown rice, such as chlorophyll, anthocyanins.
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 and other coloring matters of the rice in nifimo tempo than the fatty components.



   After polishing, various combinations of finishing stage can be used as desired. For example, when the extraction of the fatty components is not combined with the polishing, at least a major part of the rice can be separated during polishing, and the separated bran can be passed directly to a processing stage. bran drying. Polished rice containing a certain amount of bran can be passed simultaneously through conventional non-polishing sets, such as dehullers.
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 "second break", "pearl cooking" cones, etc,; '. "- c or can be transported by a stream of air or other gas, such as a hot flue gas mixture in a cyclone collector-separator.

   A cyclone of
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 this type has a rough internal surface and a fixed central cylinder is disposed in an upper part of the interior of the cyclone. The cylinder is, \ 1> 1 '#j,> ./ "formed by a wire mesh and provides an annular space S' i 1 -; between the cylinder and the wall of the cyolone in which the rice and bran are introduced. through the air.



  The rice and bran swirl in the annular space, the rice is polished, and the heavier rice is extracted from the bottom of the cyclone, while the bran is carried
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 ; upwards to tnvofs a central part of the cyclone by a flow of gas in the opposite direction and is trace.

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 carried to conventional collecting and drying stages desired.



     S.:lon a- variant, when polishing is carried out without adding colvant, auaceptible to eliminate the fatty components of the bran and the germ. the separated rice and con can be extracted together from the polishing stage. The ne * lance of rice and bran can then be introduced immediately into a solvent extractor, which can be of the movable basket type or other conventional type, and the fatty components and the coloring matter are extracted from the unseparated rice and bran. After the extraction, the solvent is separated from the rice and bran and passed through an appropriate solvent recovery system where the rice oil product is separated from the solvent and the solvent is recycled.

   After extraction, the rice and bran are passed through stages of air separation, sieving or other separation stage and after having separated from the bran, the rice can be passed through polishing stages or any other stage. desired finish,
Polishing or extraction bleaching can be used in combination with the bran softening step described above. In the present embodiment of the invention, brown rice containing a liquid bran softening agent is bleached in the presence of a solvent having the effect of extracting the fatty components from the rice.

   It can be done in a single polisher or in dry polishers in series corresponding to approximately

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 the arrangement of the "first break" and "second break" bleach polisaouooa of procda clanuiquen, maia 1. ^, provided with a liquid phase solvent in contact with the rice significantly dilutes the blanching pnr requestor extraction ### # - dia methods do blnch1mcnt h sec claooiquea.



  When using a pollosago or bleaching in the presence of a solvent capable of extracting the fatty components of the bran and the germ, it is often
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 It is desirable to use a series of extraction procedures, at least one of which is an extraction, balancing the operation of blnch11aent. For example, in a practical application of the present proceda, rice is treated
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 .: - brown after decorticago with a ugunt of softening - in an amount which will soften and do- <.



  ; remove the revôtemont from its due grains of rice. The a, '' #: kind of softening, in this case, can be Otro avtxnta->: f geuaemcnt golden oil or rice oil con ..). ,), r holding a solvent. The white aon is removed from the rice grains in the presence of the raaollia- '#' ##; are sown and a stream of oolvent containing rice oil is made to flow through the pollepun contact of the rice.



   In a particular application of the method,
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 the rice and the similar bran are extracted from the roliesouae to bring them to an additional extraction stage which can be carried out in an extractor of the mobile basket type or of any other type which allows the concurrent flow ot / or h counter-current of the solvent through the rice and read its coming out of the

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   polisher. A solvent effluent containing fatty components and coloring matters extracted during the bleaching is drained from the polisher and passed again through the eon and the rice preferably against the current thereby extracting an additional amount of the components. fat and the coloring matter of rice and bran and it presents

    a * - greater concentration of fatty components, At least part of the concentrated solution thus obtained is evacuated from the solvent and the fatty components in order to introduce it into a solvent recovery system where the solvent is separated from the oil of rice and the solvent is returned to the system. The solvent containing the fatty components of rice is hereinafter called "mixing".



   The fresh, brought back solvent is passed against the rice and the bran from the previous extraction stage, thereby substantially completely removing all the residual concentrated mixture and the fatty components, which remain. tent in the matter. The rice-bran mixture is then passed through stages in which the residual solvent is evaporated from the rice, preferably using moderate heat and stirring, the rice and bran freed from the solvent are separated and then passed. rice in any polishing or coating stage that may be desired.



   After passing through the rice and bran in a countercurrent flow, the fresh solvent contains a certain amount of rice oil and

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 at this point, it is called "If 61'inge weak". We can combine the weak mixture with part of the m6-
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 The mixture will be concentrated, which is taken against the current with the rice and the bran immediately after the evacuation of the rice and the bran from the polisher, and the udlnnge ainni obtained is passed through the polisher to remove the solvent from the polisher. .tr1ction during bleaching.



   In another practical application of the present proceeda, the bran is softened on brown rice as de-
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 Herein is written and bleached in the presence of the softening agent and a stream of solvent passing through the polisher in contact with the rice.



   The rice is admitted into the polisher at a selected rate. and a selected back pressure is applied to the rice passing through the polisher to provide the desired degree of friction necessary for any particular degree of bran removal.
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  <In this application, '' 'the solvent stream passing through the polisher is a concentrated mixture, containing oil extracted from the bran and germ in the later stages of extraction. Flow
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 of solvent and rice is preferably, although not: i / necessary. against the current throughout the operation. The bran is removed from the rice by rubbing it in, the polisher by rubbing the rice against a sieve with mesh openings and by rubbing the grains against each other and the flow of the concentrated mixture does not flow only through. through the rice, but also along the outer side of the sieve

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 and carried the sound passing through the united t'.

   A large proportion of the no this thus separated from the rice in the polsatux,
The rice and the residual bran it contains are then passed through a separator-extractor where it is again extracted with a weaker mixture. The separator-oxtracer is preferably a varicala reservoir and the rice and the mixture are stirred in a sufficiently vigorous manner so that the.

   its remainder, which adheres weakly or is washed off the rice by the mixture and enters through a sieve or mesh or other separation device. This operation is preferably carried out by introducing the rice at the top of the reservoir so that it is deposited through the vortex liquid., nant, the rice, now free of bran, is taken out of the extraction and separation tank, passes through a solvent removal apparatus and preferably passes through two stages additional extraction along the way. In the first of these stages of extraction, the rice is washed with a very dilute mixture and in the second stage, the rice is washed, with fresh solvent to remove all traces of oil and mixture.



   In the solvent removal apparatus, the rice is stirred and heated moderately to evaporate the solvent from the rice. All vapors from all extraction stages pass through a solvent recovery system. The bran and the solvent are passed from the ex-

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 traction and do 8 <2pnrntion in a settling tank of dilute mixture where the ion is deposited at the bottom of the tank to form a diaperoiont This slurry or dispersion is passed through a rdeorvoir deoan- turn of the concentrated mltlangu where it is combined with an e Concentrated fluont containing oon from polioscusf and further decanted to force a disporalon or slurry of the unconcentrated.



  The porridge is passed from oon concentrate to trti
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 , to a filter, preferably of the rotary type, and the resulting bran cake is washed on the filter
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 . firstly, the diluted clarified rdlnngc coming from the decantation tank of the diluted mixture and it is subjected to a final washing with substantially fresh colv7int from the last etidc of the rice washing, thus extracting the fatty components and the , coloring matter or its. We then pass the sound coming from the pole, <d <) filter in a doasiocatour v
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 , and dries it, while the mixture is passed through
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 -'centered from the filter in don stages of separation. Oil recovery and solvent recovery whereby the rice oil is separated from the solvent and the fresh solvent is recycled to the last stage of bran washing.



  When a maximum oil recovery is to be obtained, the envelopes or
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 ballea and the unseparated during the decor stage-
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 tionge with brown rice allowed dn the et-de of bleaching 2,;, mlnSent when it is desired that the degree of bleaching effected in 3 the polisher is reduced to wool part of the layers of bran on the

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 rice, the flow of the eclango concentrated, which passes through the polisher bare contact with the rice, softens on the 8
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 pig bran enough to provide the desired degree of blanching without breaking the grains in an axc4ebiv way ,:

   The concentrated mixture, in this case, surviving both bran softening agent and solvent, results in the concentrated mixture being relatively rich in oil from the extraction process. Maintaining some of the inner layers of the bran including the aleurono layer increases the protein and mineral content of milled rice.



   Thus, it can be seen that the preliminary softening of the bran couchos can be used in combination.
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 naison nvoc various subsequent atdos, obtaining in each es the advantages of one.? reduced abrasion nuoccsairo to separate the bran from the kernels, reduced kernel breakage and greater operability of the blinchuent stage. Thus, the softened bran can be removed by blanching without adding a solvent, the rice and bran can be separated and finished by conventional methods while obtaining the advantages above.

   Rice and bran from the blanching stage can be immediately extracted without separation with a solvent to extract the fatty components from the bran and germ, and the result is obtained. the additional advantages are that one can obtain a rice oil of good quality, which presents a good color and a low acidity, one rai-
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 its the inhibition of the Doo Motion enzymes.

   We also obtain a product of rice perfected in this

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 sense that the rice and the bran are free from fat, have a better quality of er? a1OD. are sterile and free from insects or eggs of inaootea, ct the rice pr,) (3, 'ntú of better quali- fia do cooking, better color,
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 a better taste and a more beautiful phyoic aspect than those obtained when the rice is not extracted immediately after blanching.

   Rice oil recovered from the solvent is clear in color, exhibits low acidity and is easily refined to an edible oil. We get them. advantages above to a greater extent, when. that the bleaching is carried out in the presence of a solvent in which the solvent carries out the extraction and removal of fatty substances and coloring matters, from the bran and the gorme of the rice simultaneously with the bleaching, maintains the bran in a wet state and,
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 softer and softer during bleaching,

   acts as a sweep medium to remove the separated sound
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 by washing the rice and cleans the openings of the sieves and other parts of the apparatus to rid them of bran and acts as a cooling agent
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 spawning the blanching, thereby effectively preventing the rise in temperature due to friction and preventing the increase in temperature of the rice.



   When solvent extraction is to be used, suitable solvents are petroleum fractions, such as n-hoxano, n-heptanc, eto,
 EMI16.6
 aloools com ::: o ethnnol or ioopropnnol, which

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 may contain a relatively small proportion of dissolved water or a mixture of a non-polar solvent, such as an alcohol or an ether.

   It is also possible to use chlorinated hydrocarbons, such as dichlo-
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 rure # 6thy1n. trichlorethylene, tetrachlorethylene and chlorinated ethers, such as dichloro-ethyl ether. These solvents and mixtures of sol-
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 These may be constant boiling azeotropes containing water or they may be anhydrous when introduced into the system and become azeotropic upon absorption of water. When there is an excess of water in the solvent, a
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 means in the dolvant recovery system for separating excess enu from the solvent in a conventional manner.
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  All of the above solvents, not only eg "." Milk the fatty compounds of rice bran and germ, '/ i: i [Lais inhibit the action of oxidases, lipases and:;.-..- possibly other enzymic materials and ex-
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 milk certain coloring matters, such as chlo-, {> '' '' '* 1, rophyllo and anthocyanins in rice. The best quality of the rice produced is an effect of the inhibition and '.



  .., f 1V1 of the extraction of the enzymes and of the sterilization '-': # carried out by the solvent. Solvent extraction during bleaching increases the beneficial effects obtained by extraction immediately after bleaching. Apparently, no appreciable ozyaic action occurs when using solvent extraction and thus
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 , r1 has better quality, better color,

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 lower acidity, compared to glue obtained by extraction after bleaching.



   It is evident that bleaching by ox- traction requires an apparatus, which differs from deo types
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 which we have on the market. An apparatus for performing extraction bleaching is characterized by a Dean for passing a stream of solvent through the polisher into contact with the rice. Means are provided for admitting the rice into the polisher and the polisher itself has means for exerting a desired degree of back pressure on the reef as it passes. So the rice is extracted and
 EMI18.2
 bleached a1multqnéf'JQnt during its passage through one or more polishers.



  "An apparatus of a preferred type is shown \: '..,.],' '.). In Figures 1 and 2 the accompanying drawings in the -", j / which reference numeral 1 denotes unu generally a set consisting of three elements, - :. ". '<,' \. '#;' ## # substantially similar to a horizontal bleaching device, as well as a tandem transmission to
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 variable speed. The three elements are arranged in series and each have an inlet 2, an outlet '?' '"" -' 3, a cylindrical casing 4, a metal element11- ':' hs, N that drilled cylindrical or wire mesh 5, lateral - leent spaced from the casing and a central rotor 6 inside the wire mesh.



   Each element of the series is substantially identical, except that the direction of short spines fileta 7
 EMI18.4
 arranged helically on the horzMtal rotor 6 of the central element is opposed to co41 duq threads

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 back two other elements. A spiral tape 6 is arranged between the casing and the wire mesh and affixed to the casing at a selected distance from the casing to support the wire mesh 5 rigidly at a desired distance from the casing. loppe-ut to provide a helical path for the liquid flowing through the apparatus between the wire mesh and the casing.



   Each onvoloppu is equipped with pipe fittings 16, 17, 18, 19 and 20 for the liquid so as to be able to send a flow of solvent through the element, either competitively or against it. current, relative to the movement of the rice through it.



   The Botanique fabric is preferably made of perforated metal or heavy wire mesh, which has perforations or mesh openings of too small an area to allow a grain of cerxaes to pass through them. The wire mesh, by virtue of the orifices, has a rough surface suitable for rubbing the bran to remove it from the riser, and the stream of solvent passes freely through said orifices. The texture of the perforated surface or the wire mesh may vary to suit the degree of whitening of each successive element. Thus, the first element can roughly cut into the bran layer and the others can cut into them with a finer cut, which tends to polish the grains of milled rice.

   Roctangular or oblong orifices are preferred, since

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 The strong oe holes reduced the duo grain of rice cry due to a sharp end of a grain getting stuck in a hole The 7 oc helical threads preferably overlap each other over a half.
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 about the arc of the rotor surface - covered by a corresponding thread in a group of successive threads. The rotor 6 is supported by pa0-
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 will connect 9 and 10 at its ends and is driven by any suitable transmission shown as a series of sprockets and chains.
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 , 4,

  "dragged by a motor II via a ,, reduction gear assembly 12. Each of the elements has an inlet 2 arranged to introduce the rice onto the surface of the rotor 6 between the rotor and the ", # t;: perforated sieve 5. A means is provided to exert: .4". Back pressure on the rice and it can have a z '7 # "' (# '? * <. certain number of shapes. For exompld, the back pitch .- zip
 EMI20.5
 helical threads 7 of the dornior element of the series' V * '# - "# ##' V '; may be slightly larger than the pitch of the previous elements,:;, menti3 or the pitch may increase progress-.' .; #> '> strongly from the first element we go through the second "}% Up to the third element.

   However, one must avoid too great an increase in the pitch, as this would cause the polisher to jam. According to a variant, the pitch of the helical threads 7 can be the same on all the rotors and the transmission can be arranged to drive a successive element at a lower speed, variable speed pulleys 13 and 14 and a trapezoidal belt 15

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 illustrating a type of variable transmission of this
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 gonro, Bn all one # the helical threads of a successive element and the means of transmission co-brunt to exert a desired degree of counterprossion
 EMI21.2
 on the rice d :: na a preceding element.



   A liquid solvent is introduced into an element of the series and it is possible to pass it 4 through it, either in a competitive manner or against the current with respect to the direction of flow of the rice in the flow. polisher. It is preferable to introduce the solvent into each of the elements in a successive manner.
 EMI21.3
 coesive ot to make it pass in a countercurrent flow through all the elements. The agency- =, .raant represented is likely to pass the. <;; y solvent has countercurrent flow through:; each of the polishers successively, then in successive stages to separate the bran, ex- ¯ '# - "' 'further silence the rice and the bran and recover the solvent and separate the rice oil as previously described.
 EMI21.4
 Figures 3 and 4 show another type of bleaching device.

   In figure 3, the number
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 20 shows a hopper superimposed on a bleach portion generally designated by
21, which discharges by means of a chute 22 on a
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 helical screw conveyor 24. The conveyor screw consists of an outer tubular casing 23, a helical screw 25, a discharge chute 26, a transmission means shown under the force of a pinion 27 driven by a motor. 28

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 via a reduction gear 28a.

   
 EMI22.1
 The polisher was entered by a suitable control means shown as a speed motor.
 EMI22.2
 varinblc 29 arranged to drive a central rotor 30 by means of a reduction gear 292 and of a trbru d; transnioaion 34. This rotor is located concurrently with a cone 31, which may be of perforated metal or of a suitable wire mesh.



   The rotor has 32 helical threads
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 on oc surface, which are agenode in a way that when the around drives the rotor, the helical threads
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 oppose the passage of the rice from top to bottom through the polishing machine and direct the rice strongly against the
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 c8t -. & internal of the perforated cone * The rice is admitted from top to bottom in the perforated cone outside the rotor and it escapes through an opening 33, which surrounds the central transmission shaft 34 .

   The conical rotor 30 also has a number of ribs.
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 runners 35 (as seen in particular in Figure 4) which coincide at the periphery of the cone with the lower end of the helical threads
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 32. These scraped ribs rotate at substantially the same distance above a horizontal tamin 36 as those existing ontr; the rotor and the cone perforated so that they tend to sweep the rice from the bottom of the cone into the central opening 33.



    It is preferable that the conical rotor is adjusted
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 vertically on the tranominaigil shaft $ 4 bare means of fixing screws 34 or other adjustment means of tmniere to be able to adjust vortioally the

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 rotor on the commando shaft. Conducted vertical movement is required to effect small changes in the width of the annulus between the perforated cone and the rotor, and the setscrews thus provide a convenient means of accurately adjusting this next annulus. the type of grain being polished.



   A means is provided for passing a stream of liquid solvent through a casing 37 along the sieve 31 in contact with the rice in an annular space between the rotor 30 and the unit 31 and said means is shown in the form of 'a pump
38 connected to extract a purified mixture from, an upper part of a deoantation tank
39 through a filter 40 and to introduce the mixture extracted through a pipe 41 inside the casing 37. the mixture recycled after having passed against the current with respect to the rice in the polisher is discharged through a filter 42 and through a pipe 43 in the settling tank 39.

   According to a variant, it is possible to establish a connection with the pipe 43 by means of the pipe connector 43a represented as being blocked and the mixture can be conveyed into the settling tank 39 from this. point. Thus, recycling is planned and a secondary current can be taken from the pipe.
44 and pass it through a solvent recovery system arranged to separate the oil and any excess

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 dea'u, which may exist as a conditioner or in some extraction stage of the process where ul may be useful.



   A dispersion of the concetré mixture and of the bran is evacuated from the bottom of the tank of the dxcatio 39 and passes? by lines 45, 46 and 46a for washing a mixture of rice and bran leaving the polisher in a lower part of the helical screw conveyor 24. A secondary stream of this material can also pass through a line 46 in a upper part of hopper 20 to serve as a bran softening agent. A second secondary stream of the concentrated mixture carrying the suspended bran; passes through line 47 to the sound separation and solvent recovery stages or to any other desired extraction stage.

   The maximum concentration of the concentrated mixture is preferably maintained at a maximum of about 10% oil so that it exhibits good extraction properties.



   The bran passing through the orifices of the sieve 31 is deposited in the casing 37 and passes through the orifices 48 formed in a horizontal plate 49 of the polishing machine so as to extract the rice and the bran from the polishing machine without separating them. and to make them penetrate into the conveyor life 24.

   A more dilute mixture from a later extraction step or fresh solvent from the solvent recovery system is introduced into one part. top of the conveyor via 24 by a conduit 50 so that the mixed rice and bran are evacuated.

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 had d; the polisher undergo a backwashing at gentle stages in the conveyor 24.

   It is obvious that the conveyor via 24 extends upwards by a sufficient distance indicated by an interruption in the drawing, so that the pipe 50 is connected with the conveyor at a point slightly above the level of the filter. 42 so that; the solvent introduced through line 50 flows from top to bottom through the conveyor.



   The rice and bran then pass through discharge chute 26 in any desired extraction, separation and finishing stages.



   The level of the mixture in the conveyor 24 is controlled by a valve 51 located in a discharge duct 52 into which is introduced a filter 53 which contains a sieve with coarse perforations which is capable of retaining the rice, but which allows passage. the solvent and the fine bran particles in the settling tank 39.



   Figure 5 shows another arrangement of an apparatus suitable for carrying out extraction bleaching. A feed hopper
51 is designed to feed a mixing conveyor 52 into which a liquid bran softening agent is introduced in a desired proportion through a line 53 or 53.



   From the conveyor 52, the rice containing the bran softening agent is discharged into a ribbon mixer 94 and after thorough mixing it passes through a suitably designated tackifier.

 <Desc / Clms Page number 26>

 general by A and which is preferably constructed,
 EMI26.1
 as described, reference is made to FIG. 1 or with reference to FIG. 3 above.



  From the oortic of the lu polienoueu the rice containing the residual bran pas'oe in an elevator 55 and .and 1-iv-, 'all passing 4 through the elevator in a mixture reaping a moderate concentration
 EMI26.2
 entered in line 56, The mixture of rice and ..



  , its alora passes into an extractor separator tank 57, having stirring vanes 58 and 58a
 EMI26.3
 ', cor ... andéea pnr toteur and which would have alinonté one mixes -, diluted introduced from a united pipe 61 into an evocation elevator 60 and a conveyor via 63. the flow of rice is thus carried out against
 EMI26.4
 current relative to the flow # have liquid contained in the separator tank 57.

   The heavier rice sinks into the liquid and is extracted by a conveyor screw 63 and discharged therefrom into the elevator 60.
 EMI26.5
 The bran suspended in the mixture passes through a screen 59 and through a line 64 and passes into a settling tank 65 from which a dispersion of bran and mixture passes into a second settling tank 66.

   A dispersion of
 EMI26.6
 sound in a concentrated tdlnnge is drained from leser- see 66 and passes through a filtra 67 shown to be of the rotary type and is washed on the filter first with a more dilute mixture carried by.
 EMI26.7
 line 68 and finally by almost fresh solvent transported by line 69, These lifting operations leave the sound substantially free of oil.

 <Desc / Clms Page number 27>

 
 EMI27.1
 It is read and then passed into a sound processor by means of a key 70. The sound processor can be of any type desired, although the one shown is of the turntable type.

   From the
 EMI27.2
 Desiccn.teur, lybon is discharged through a wsouption chute 71 into an elevator 72 and proceeds to the desired bagging or finishing stages.
 EMI27.3
 The bran-free rice is discharged by the léldva. feeder 60 into an inclined conveyor via 73 and is subjected there to a final wash with fresh solvent from the solvent recovery system entering via lines 74 and 74a. The washed rice is discharged by the conveyor 73 into an intermediate tank
90 and thence to a solvent removal apparatus 92. The latter may be of any desired type, for example a shaker arranged to shake the rice in a stream of superheated solvent vapor.
 EMI27.4
 frée and / or a hot inert gas.

   From the solvent stripper, the rice is discharged into '"- 93 and can be sent for storage, to bagging operations or to all finishing stages.
 EMI27.5
 wanted. The clarified concentrated mixture from an upper part of the settling tank 66 is discharged by a pump 78 and is fed to the slipper A through lines 79 and 80, thus providing the solvent for the extraction during the bleaching. .

   The oil content of the concentrated mixture
 EMI27.6
 is kept low enough for it to have good extraction properties by continuously discharging the concentrated mixture from the bottom of the tank.

 <Desc / Clms Page number 28>

 see decant 66 and introduce a more dilute mixture from tank 65,
Vapors from the apparatus shown August are sent to a solvent re-cut system designated 76 and the concentrated mixture from reservoir 75 fed from the filter is sent through line 77 to the system.



   The solvent recovery system can be of any desired type as long as it performs the separation of the rice oil from the solvent and the separation of any excess water, which may exist in the system. . The solvent recovery system designated apr 76 comprises means for condensing the solvent vapors introduced through lines 82, 83 and 84 and means for separating the solvent from the rice oil received through line 77 and a means for separating the excess water from the solvent and for removing the water, as indicated by line 85. The solvent and oil recovery system is not shown in detail, since it is It is simply an arrangement of a conventional apparatus and which in itself the invention.

   A container 86 is connected to receive fresh purified solvent from the solvent recovery system and to return fresh solvent to the extraction system through line 74. Container 87 and a pump 81 are connected to receive. rice oil from the recovery system and can be connected to a line 53a by a line 88 oom-

 <Desc / Clms Page number 29>

 controlled by a valve to recyolate the rice oil as a bran softening agent in the mixer conveyor 52. According to a variant, the rice oil containing the residual solvent can be discharged from the sutiZme for recovering the solvent by a pipe 89 ot recycled in the pipe 53a.

   Line 88a, controlled by a valve, is provided for pumping rice oil into a storage container.



   When the non on the rice is softened by a liquid softening agent, as described above, and is removed by polishing the rice grease without simultaneous solvent extraction, conventional equipment can be used for the bleaching stage or the polishing apparatus 1 of Fig. 1 or 21 of Fig. 3 can be modified to effect this bleaching. For example, instead of a separate envelope 4 surrounding each element, as shown in Fig. 1, a single envelope surrounding the three elements can be used so that all sound passing through it. opening on the sieves 5 falls to the bottom of the single casing.

   From this point the bran is discharged and dried in a conventional manner, while the rice containing the residual bran is discharged from the polisher to any conventional drying and separation stages or to processing equipment. - traction, like that shown at 57 in Figure 5.

 <Desc / Clms Page number 30>

 



   The special polisher of figures 3 and 4 can also be easily modified to perform - dry bleaching by omitting the circulating system of the solvent and admitting pressurized air through the nozzle 43a for push the sound out of the tubular casing 23.

   In this case, the rice containing a liquid bran softening agent is admitted from any suitable source, such as the ribbon mixer 54 of Figure 5 in the blanching section 21 of Figure 3. the rice and bran are discharged on 22 and can pass through conventional drying and separation stages or they can be introduced into extraction equipment, such as for example a mobile basket conveyor or extractor 57 of Figure 5, and solvent extracted therein immediately after bleaching and before separation.



   In the embodiment shown in Figure 6, the rice from the main tank P1, which has undergone a softening treatment in a previous apparatus, as described above with reference to Figures 3 and 5, is admitted by means of conveyor screws 110 and / or 110a into the corresponding combination of solvent extraction and polishing apparatus G1 and / or G2.

   If the combination of devices 01 and 02 works in parallel, the two conveyor screws are in operation * If they work in series, only the transport via 110a works. The helical thread of the conveyor screw 110 at rest effectively ompô the eco8u-

 <Desc / Clms Page number 31>

   filing rice into apparatus 01 and also prevents loss of solvent vapors from strippers and polishing.

   A conveyor screw 110b receives the material from the apparatus 02 and conveys it to a flap 11 la which determines whether the milled rice and bran from the apparatus 02 flowing directly to the machine. inclined conveyor 111 through chute 11c and thus constitute products of bleaching at this stage or if the bleached products from apparatus D1 are diverted through chute 111b into apparatus 01 to undergo bleaching. second stage of whitening. These processes can be compared a big to the "first break" and "second break" polishing of the conventional dry polishing process.

   Some polishers perform single-break polishing or bleaching, which would be comparable to operating the solvent extractors and polishers G1 and G2 in the parallel "single-break" fashion. Of course, in both cases recourse is had to the simultaneous use of the solvent extraction processes while polishing in the liquid phase, which distinguishes the Applicant's process from conventional rice polishing.



   The construction and functional peculiarities of the combination of solvent extraction and polishing apparatus G1 and G2 are identical in that the reference numeral 112 denotes an outer metal casing, which serves to create the apparatus. , the reference number 113

 <Desc / Clms Page number 32>

 
 EMI32.1
 denotes a taUd y rim, îi on 4 {i pbttS or en tOile'mdtaii14do t Q, riùtadrd d c i'sr'nco, 11 S denotes a conveyor via, which trhnSbrto 1Q starts from the zone of the hopper formed;

   by the envoloppo 112 and the inclined bottom 113, the Muuéro of reference 116 designates a perforated metal or wire mesh stator in which a rib rotor rotates 117 The stator and the rotor have either a cylindrical shape, either conical and the ribs of the rotor can be arranged either vertically,

     either we diagonal
 EMI32.2
 relative to the vertical dimension of the rotor and are arranged 45 to 90 from each other around the circumference of the rotor. The opening between the rotor and the perforated stator is adjustable by raising or lowering the position of the rotor on its shaft in any suitable way, while keeping the stator in a fixed position. Of course, it is pos-
 EMI32.3
 It is possible to use an apparatus in which the position of the rotor is fixed and that of the
 EMI32.4
 stator to)

   up or down to vary the play between them in a range between 6.35 jE: 'U entt', r ', iwnmo eomilrieo nre 6,' 5. ', and 19 mm. Smaller clearances tend to increase the polishing action, but limit the throughput while the opposite is true when using clearances. bigger.

   
 EMI32.5
 The discharge from pump 18 is channeled so that by forming valve V5 and opening valve V6, the diluted mixture from tank compartment 17a can be used in the primary extraction stage, also, in

 <Desc / Clms Page number 33>

 opening valve V7, when valve V5 remains closed, half of the mixture from pump 128 can be sent through line 20a to an intermediate extraction stage in a conventional movable basket extractor.



   Simulate with the introduction of unbleached brown rice or partially milled rice, when a bleaching is carried out in series using two combined devices of extraction by a solvent and of coating, a solvent capable of extracting the fatty substances and the coloring matters The layers of bran and polishing substances are introduced through line 134. The solvent may be fresh solvent from the solvent recovery and oil recovery stages previously described, but this is usually the case in one. extraction process. multiple of a diluted mixture coming from a chamber 17a of a lower part of a conventional mobile basket extractor.

   In the present case, the diluted mixture coming from the pump 18a is delivered through line 134 into the device G1 and / or the device G2 via the valves V3 and / or V4 respectively to the inlet fittings 114 or 114c and flows countercurrently from bottom to top through the descending column of rice and polishing substances between the rotor
117 and stator 116 and exits through exhaust fittings 114a or 114b. The rotor 117 is driven at selected speeds from a wide range by a motor and a transmission 120 including a speed reducer.

   Smaller devices require

 <Desc / Clms Page number 34>

 more scolded speeds than the greater apparatuses to obtain a polishing and an equivalent flow rate for any given clearance between the stator and the
 EMI34.1
 rotor, attndu'11 s'r, bit of a concept of peripheral speed expressed in miters per second All liver, quickly say its excessive pdrlphriqud to the real conditions of the polishing cause an excessive brilliance. Applicant's speed range expressed
 EMI34.2
 in revolutions per Q1nut can vary ontrq 600 revolutions per minute approximately for a rotor of 45 cm 200 revolutions per minute for a rotor of 150 cm, when a high degree of polishing is desired. Slower speeds were used to achieve a below average polishing or bleaching.

   If higher pressures are applied in the opening between the stator and the rotor by levels
 EMI34.3
 grain higher in the hoppers and chutes above the rotor or if a forced intake is provided, the speeds can be reduced further
 EMI34.4
 sus-mènt10nnÓeB. In general, the use of solvent traction simultaneously with the bleaching increases the ease of removal of the coating from its. ". 1, ... * 'and satisfactory bleaching can be achieved at both speeds and rates. \ pressure against the chipmunk
 EMI34.5
 polishing interferes with those of conventional dry polishing processes.

   It is the same when using an agent for remodeling the layers of @on without simultaneous extraction with a solvent in
 EMI34.6
 the polishing machine, but in large corners o measurement.

 <Desc / Clms Page number 35>

 



   Whether the flow of solvent through the polisher is concurrent or countercurrent is not critical if further stages of extraction in other apparatus follow. Thus, the flow from line 154 can be introduced through connector 114a and can exit through connector 114 instead of the other way around.



   The mixture of milled rice and policsae substances from the bran layers falls into the lower hopper 118 where it exits the apparatus through the conveyor screw 115 and passes into the inclined conveyor screw H1 through the goulotto 121. The The solids are transported from the bottom up and introduced into the conveyor screw J1 and from there to an upper part of a conventional movable basket extractor, as indicated at 15, while the solvent contains the oils and coloring matters. extracted continuously flows into the mixture settling tank II through a rotary filter 12 and through a line 123.

   The line 133a and the valve VI can also serve as a means of flow of the solvent containing the oil into the reservoir II, but normally they are only used for draining the installation.



   The diverted half-mixture, known as described above, passes through the melingo decantation tank II where most of its sound is deposited and is discharged through the sludge evacuation valve V2, which can be operated either manually or automatically by

 <Desc / Clms Page number 36>

 
 EMI36.1
 sludge density regulator (not rerdicht6) i it works by pump 1) 2, of the positive displacement diaphragm type i must be coordinated to operate only when the vanna V2 is open and admits sludge into the pipe 130 .

   The sludge evacuated by the pump enters the coudutie 133 and passes into the conveyor at via inclina Hl
 EMI36.2
 at a point located slightly below the level of 11 * which is the installation. The domi mixture is evacuated
 EMI36.3
 , and the evacuated mud joins the melancho of whitened ri and of son 'which passes in the conveyor screw il @' -The main volume of the half mixture goes down along; of the central chicane shown in dotted lines at:

   right of 11, goes up through the deca-
 EMI36.4
 linked shown in dotted line to the left of Il and exits through the filter 125 and the pipe 126 in the intermediate tank 127. The pump 128 sends
 EMI36.5
 then the half mixture through line 129 in line 20a from where it is admitted into an extractor of the movable basket type. It is then used in the intermediate extraction stage, which is conducted
 EMI36.6
 against the current, as previously described.

   The concentrated mixture obtained during this second stage
 EMI36.7
 extraction is collected in the chamber l'b and: is then sent to the oil and solvent recovery installation described above and the mixture of milled rice and bran is then subjected to the extraction and rinsing stage final, as the baskets rise against the current

 <Desc / Clms Page number 37>

 stream of fresh solvent above the chamber
17a. The extracted solids are then admitted into the conveyor screw 23 and enter a solvent removal apparatus similar to that designated 92 in FIG. 5 and pass through the atadoa ruutants, as previously described.



   Of course, the invention is not limited to the embodiment described and shown and is capable of receiving various variants falling within the scope and spirit of the invention.



   Equivalent equipment to that shown in the process is envisaged. For example, other variations of horizontal and vertical polishing machines can be used. Also, instead of carrying out secondary stages of extraction and recovery of the solid material from the bran in conveyor screws and rotary filters, it is possible to offer multiple stages of extraction in a series of settling tanks in centri. - tank type casks or by combining decanters with centrifuges. Instead of a sound turntable solvent removal apparatus, a rotary drum or fluidized solids plants can be used.



  The batch can be discharged in a moving bed in a vertical column or in a fluidized solids plant instead of the rotating drum shown in Figure 5.


    

Claims (1)

EMI38.1 R 3 8 U M 3 A) - Process for polishing or bleaching brown rice, process characterized by the following points separately EMI38.2 or we combine.iaona! 1. It consisted in mixing a liquid bran softening agent with brown rice in an amount sufficient to soften the bran located on the grains of rice. EMI38.3 rice and removing the rice by polishing in the presence of the bran softening agent. , 2. It consists, in addition, to subject lo its ot lo rice from the bleaching or polishing stage. at an extraction stage without separating the bran from the rice, at EMI38.4 extract the bran ot the rice mixed with a solvent which can be used to extract the crane component and the coloring matter from the bran and the germ to separate the eolvont against the fatty component and the bzz coloring matter from the mixture of rice and bran, to separate the rice oil from EMI38.5 solvent, separating the solvent from the mixture of rice and bran and separating the rice from the bran. 3. The softened bran is separated from the rice by polishing, in the presence of a stream of solvent capable of extracting the fatty components and the coloring matters from the bran and the germ, again extracting both the rice and the bran. with a solvent after:. have evacuated the sound ot EMI38.6 The rice of the '7C138ûFC eteidt ot the rice oil is separated from the solvent. 4. The ion of a mixture of rize and its removed from the polishing step with a solvent is washed out during an extraction step after the plisaga step. 5. 0.25 to 5 percent of the liquid bran softening agent is mixed with the brown rice and the resulting mixture is kept laying a <Desc / Clms Page number 39> sufficient time for the bran to be rice seed Drinks softened and comes off before polishing. 6. The rice and the liquid bran romollissemnte agent are aminticnet at a temperature between 62 and 60 C. during the holding period. B. Apparatus for bleaching or polishing brown rice comprising a .; pelissuss to admit the brown rice into the polisher, apparatus characterized by the following separate points, ent had a combinations t 1. It comprises a means of extraction by a solvent arranged to receive a mixture of bran and rice from the polishing machine and to pass a solvent capable of extracting the fatty components and the coloring matters through the. mixed. 2. The polisher provides a means for passing a stream of liquid solvent through the polisher in contact with the rice being bleached. 3. Provision is made for a separator tank - extractor to receive the rice containing residual bran from the polisher, a means located in the tank for agitating the rice and the solvent located in the tank for separating the solvent containing the bran. the bran is suspended from the rice and a means for extracting the solvent containing the separated bran from the reservoir. 4. The polishing machine comprises a series of assemblies, each assembly comprising an elongated horizontal cylindrical time having orifices very close to each other substantially over its entire surface, said orifices having a dimension capable of allowing the passage of the no and of remaining. rice grains, <Desc / Clms Page number 40> EMI40.1 a cylindrical rotor has it. <. rie of the tkaië and concen- trate to this last challenge: h an annular ootatfi in- tr ,. the chipmunk Lt 1 (roast, uno threo for lve raina in the nnnulrirc space in the vicinity of dlwi., extr, ', tlité of the chipmunk, one left for the grains from 1 *' a- ring space in the vicinity of an extracted opposite of the sieve and the helical threads provided on the rotor to direct the seeds against the sieve and to advance the seeds in the direction of exit, a means which cooperates with each of the preceding and following sets of the series to transport the seeds of the EMI40.2 output of the previous assembly to the input of the following assembly and a means connected to drive the twists, the transmission means and the helical threads - two of a subsequent assembly cooperating to exert a counter pressure on the seeds contained in a preceding assembly. EMI40.3 5. The polisher comprises a casing, a fixed frustoconical-shaped screen mounted vertically in the casing and laterally spaced from the latter and a J-.8, ",, truncated-shaped rotor concentric with the chipmunk y1r¯ 'having a surface substantially parallel to the sieve for.4 there, define an annular 6 apaco between the rotor and the sieve an entrance for brown rice in the annular space near the upper end of the sieve, a scr- tid for milled rice from space near the lower end of the screen and the ribs EMI40.4 ros hdiicoldal (, is arranged on the rotor and arranged to oppose an up and down flow of the seeds to the annular spice and to direct these seeds outward against the sieve. <Desc / Clms Page number 41> 6. Said apparatus further comprises a mixer adapted to mix a liquid bran-weakening agent with the rice before introducing the brown rice into the polisher. C. Perfected milled rice characterized by the following items separately or in combination; 1. It is substantially an example of a fatty substance, sterile free from insects and insect eggs, and exhibits better color, better taste and better cooking qualities. 2. It is bleached to a lower than average size and retains at least a large portion of the minerals and proteins of the internal layers, including the aleurone layer.