US1980589A - Capillary colloid - Google Patents

Description

' Nov, 13, 1934. s. F. AGREE 'Y cAPILLARY coL'LoID MILL Original Filed Sept. 11. 1924 2 Sheets-Sheet 1 NOV. 13, 1934. l s, F, AGREE 1,980,589

CAPILLARY COLLOID MILL Original Filed Sept. 11. 1924 2 Sheets-Sheet 2 Patented Nov. 13, 1934 UNITED STATES PATENT ori-ics Application september 11. 1924, serial No. 737,209 Renewed June 27, 1932 s china. (ci. iis-14) (Granted under the provisions of lee. 14, act of March 2, 1927; 357 0. G. 5)

art which have sought to accomplish these ends.

One of the objects of this invention is to produce processes which shall result in stable suspensions and emulsions.

Another object of the invention is to produce machines which shall result in such products and enable the carrying out of these processes eiliciently.

Other and further objects and advantages of the invention will appear from the more detailed description set forth below taken in conjunction with the accompanying drawings wherein there is shown by way of illustration in Figure 1 a vertical transverse section through one form of the device; in Figure 2 a vertical longitudinal section of the device set forth in Figure l; and in Figure 3, a vertical section through a modiilcation of the structure shown in Figure 1. Figure 4 shows a section of one form of inlet and outlet, the rotor being in elevation. Figure 5 shows a modification, the rotor and casing being made up of discs having complemental curvatine. Figure 6 is an elevation, partly in section, of a cone-type mill made in accordance with the present invention. But it will be understood that the drawings set forth the preferred forms of the invention, and that various changes may be made therein and in the processes set forth below, by those skilled in the art, without departing from the spirit and scope of the disclosed invention. This invention is based on the following considerations. When a liquid such as creosote oil, petroleum oil, etc., is passed under pressure through a capillary tube into another mutually insoluble liquid such as water, the creosote oil etc., constantly breaks off globules from the stream or column of oil at the end of the capillary tube. With decrease in size of the capillary tube, the globules decrease in size so that finely divided materials are obtained. Instead of using capillary tubes, a porous tube or plate (not shown) having a multiplicity of capillary openings may be employed, one or both of the liquids being forced therethrough. For example the creosote oil may be forced through one or a multiplicity of porous porcelain tubes at high pressure into a soap solution 'in order to form a creosote emulsion. The principal disadvantage of such operation is that the capillary openings become clogged with solid or plastic materials, which it is diillcult to remove, as by reversing the pressure or by brushing. v

To avoid these disadvantages while retaining the desirable features of such methods of disintegration, use is made in the present invention of the enormous centripetal and centrifugal forces obtainable at -high speeds, such as 10,000 to 30,000 R. P. M. or even higher speeds, to force particles of liquids, plastics, and solids into V shaped or other grooves, which act as capillaries and in which the particles of liquid, etc., become longer and longer as they pass further into the V shaped groove, with consequent diminution in cross section. As a result of such diminution in cross section, the particles become elongated like a sausage, until they finally break up into two or .more globules of small diameter, which in turn pass deeper into the groove, the above described'A process being repeated automatically under the operation of the forces described above until the particles have reached a size representing the smallest division that can be obtained with the machine used. Where a series of connecting grooves are used, the material under treatment is kept moving directly along such capillary grooves or across them. While passing across them, the particles are part-A ly forced into the groove and are broken up or cut" as indicated above, and then pass on to the next groove to be further disintegrated.

It therefore follows that a part of the total liquid should have a speed high enough, at least at intervals, to sweep the suspended materials along the groove and thus prevent clogging. With the large pressure forcing or crushing the suspended materials into the grooves, it is clear that solids will be crushed into the V shaped grooves and that plastics and liquids will act in the same way.

In a practical embodiment of this principle, the grooves may be ruled any chosen depth such as 0.1 millimeter (or 100 microns) and should be very close together on both the seat and the cone of such mills as are referred to above, or on the discs of the mills using such discs. Such grooves are shown in Fig. 6 and may be ruled radially or crisscross at any desired angles; or they may be cut into the seat or the cone or disc to correspond with the path of a suspended particle in the solution passing through the machine, or at right angles or other angle to such path, in order to get maximum shear. Each of these rulings has certain advantages, but it is very important for the best results lo place the grooves very close together, such as 0.1 to 0.5 millimeter or less apart. and to make them of fairly uniform depth. The position and angle of the V shaped groove or other form of groove when used. should be so related to the surface that the pressure forcing the particles into these grooves should produce the greatest possible rupture of the particles.

Another method of using such capillary forces in these grooves is to employ a grooved cylinder rotating at high speed in the corresponding grooves of a circular or helical or other form of casing and to run the liquid and suspended material into and radially around and out of the rotor and casing. Considering the path of suspended liquid or solid particle it is seen that at high speed such as 20.000 R. P. M., the machine acts like a centrifugal pump and that the centrifugal force exerted is very great. Hence even small differences in specific gravity between the suspended particles and the suspension medium are highly magnified with the result that the suspended particles heavier than the medium are thrown outward into the grooves of the casing with great centrifugal force while those particles lighter than the medium are forced inwardly into the grooves of the rotor. These centrifugal and centripetal forces cause the suspended particles of the liquids or solids to be forced into the V shaped grooves where the cross sections are made smaller as discussed above. The current of liquid always moves along the groove to sweep it free of material that might cause clogging. As the laws governing bodies falling in a fluid apply to these centrifugal forces, the heavier or larger particles of a given material are thrown tangentially outward when such material is heavier than the suspension medium and are therefore crushed in the V shaped grooves of the case, the smaller particles being more easily kept in suspension by convection and the lower rate of outward movement or falling. Hence the larger particles have always the largest number of chances of being thrown into the capillary grooves and of being crushed into the smallest particles. The same applies to the particles lighter than the medium which are thrown inwardly into the grooves of the rotor where they are disrupted.

There are conditions under which the centrifugal and related forces exerted in any given material under treatment is small. For example, if the specific gravity of an organic oil in suspension is practically that of water, used as a medium, the centrifugal separation may be small. Several methods may be used to modify such conditions so that advantage may still be taken of these centrifugal forces to produce the results sought as outlined above. In one such case, since as a general rule the organic substances have a coeilcient of expansion of 0.001 while that of water is 0.0001 per degree centigrade, by heating or by cooling the mixture great differences in the specific gravity and the dispersion of the materials is obtained. Furthermore, heating often causes hydration of a suspended material which weakens the cohesive forces, so that the particles are more easily dispersed.

Another method that may be used in varying .the factors that enter into and control the dispersive conditions, is to control the electrochemical conditions of the mixtures, etc., so that the particles of the materials undergoing dispersive treatment are given high electric charges and mobilities and contact potentials toward the dispersing medium. In such cases the rotor and the case within which it revolves may be used as the electrodes, and under the influence of the chosen electrical conditions, the charged larger particles are forced against the case (or rotor) to aid in the disruption.

In any such modifications, or any case coming within the scope of this invention, when it is desired to use a solvent for example like carbon disulphide, carbon tetrachloride. etc., to dissolve a material like sulphur, etc., and to disperse the resulting solution in water, which may contain a stabilizer such as soap. galaetan, glue, etc. if desired, followed by distillation etc. to recover the solvent and to leave the dissolved substance in colloidal dispersion, the solvent may be chosen with a desired specific gravity, i. e. heavier or lighter than water, so that the particles are forced outward or inward as desired and disrupted by the case or rotor and their adjacent regions of shear in the traveling film of material.

It is of particular advantage to change the tangential movement and thrust of the particles each moment by the curvature of the case and the rotor to assist in the disruption. By increasing the rate of flow of the liquid through the machine by the rotor itself or by means of an outside pump, the greater this thrust, becomes, and the more the particles are forced into the grooves as they are ldiverted from the tangential to the radial or circumferential movement in a plane substantially perpendicular to the shaft and hence the more efficiently they are disintegrited or dispersed; this fact is true of no other rotating mill of which I am aware and constitutes a highly useful novelty of my invention.

In the annexed drawings, Fig. 1 is a vertical cross section of a mill having a horizontal inlet and outlet, and Fig. 2 is a vertical longitudinal section of a portion of the length thereof, on the line 2-2 of Fig. 1. Fig. 3 is a cross section of a modified construction showing vertical inlet and outlet. Fig. 4 is an elevation, partly in section of another type of mill, the rotor being il shown in elevation with fine grooves on its surface and having a tapered inlet pocket. Fig. 5 shows a section of a mill in which the rotor and casing are grooved with shallow rounded grooves.

Fig. 6 is a different type showing a cone and conical seat adapted for spray drying.

In the embodiments illustrated in the Figs. 1 and 2 of drawings as exemplary, there is shown a grooved rotor 1 with grooves 2. the rotor being adapted to run at speeds from 1000 to 20,000

R. P. M. or even higher, within a grooved casing 3. The rotor is preferably mounted eccentric to the casing. The outside diameter of the tongues 4 0f the rotor is larger than the inside diameter of the tongues 5 of the casing. The angular relation of these tongues is important in connection with the capacity of the machine. If the angle of the tongues is 60, the width of the film and the capacity of the mill are just twice that obtained when the rotor is cylindrical and contains Ill no grooves, but is the same distance from the case as set forth below. If the angle is 30, the Width of the lm is about four times that of the smooth rotor. The capacity of the machine increases with decreasing angle of the tongues.

At one (or both as desired) end of the shaft 6, there is preferably placed a thrust ball bearing '7, in a threaded seat 8, to enable the rotor to be moved longitudinally` as shown in Figure 2. The purpose of this arrangement is to allow variation in the distance between the grooves and tongues on the rotor and the tongues and grooves on the casing. If desired, a governor may be arranged on the shaft to keep its e'nd pressed tightly against the ball bearings and hence keep the rotor in a fixed longitudinal position. Or one or more collars placed on the shaft may rotate in connection with ball bearings, the longitudinal position of the bearings and collars and hence of the rotor and shaft being adjustable and then held fixed.

The casing 3 is attached to the base plate 9. the latter being. adapted to slide on the plate 10 by means of a well fitting tongue 11 and groove 12, or other similar arrangement on the base plate 9, the movement thus obtained being transverse to the axis of the rotor shaft 6. In Figure 1, the left hand side 13 of the casing 3 can be bolted above and'below as by bolts 14 and 15 to the right side 16 of the casing 3. The left hand side 13 may also be arranged by means of a tongue 17 and groove 18, to slide on a special or secondary base plate 9. In the modification set forth in Figure 3, each half of the case 3 may slide on itsv own base plate 9'.

A screw arrangement 20 (or an equivalent lever or wedge or other arrangement) may be used to permit sliding of the casing as a whole relatively to the rotor, so that the distance between the rotor an'd casing may be varied for any desired purposes. As shown in Figure 3 the two halves of the casing may be moved independently.

'I'he casing 3 is preferably made hollow as shown at 21, 21, 21 in Figure 1 and at 21', 21' in Figure 3, to enable the introduction of a cooling or heating medium, for example, brine for cooling, or steam, hot oil or water for heating etc.; or one side may be heated while the other is being cooled, depending on the results which it is desired to produce.

The two halves of the case are usually divided in a vertical plane which permits easyunbolting and replacement of the gaskets 2'7 or 27' when the latter are used between the halves of the casing, and also allows easy separation and cleaning of the rotor and the inner walls of the casing. The tongue and groove arrangements on the bases also facilitate the reassembly of the machine with proper alignment of the tongues and grooves on the rotor and the inner walls of the casing. While this represents the preferred form of the machines, the latter may have its casing divided horizontally or it can be made in three or more parts as may be desired without materially affecting the machine as illustrated and without departing from the scope of the present invention.

The rotor 1 may be cast solid or integral with the shaft and then machined. 0r it may consist of a cylinder machined true on both the inside and outside to balance when used at high speeds; in which case the ends of the rotor may consist of two discs with left-and right threads respectively to screw onto the shaft and into the inside of the ends of the cylinder and against shoulders therein to prevent turning of the cylinder with reference to the ends and shaft while in use. Proper keys and threads hold the ends and shaft rigid, and the ends may be perforated if desired. Keys may also, pass through the threads between the ends and cylinder.

The inner surface of the oase may be cast integrally with the case; but it may also be made as a solid or split sleeve with outside circular diameter permitting it to slip into a corresponding circular opening lengthwise the case. If this circular opening in the case and the rotor are eccentric. as well as the outer and inner 4surfaces of the sleeve, a rotation of the sleeve within the case will vary the distance between the rotor and various points on the inner surface of the sleeve as desired. The sleeve can be keyed to the inner surface of the case to preserve these relative positions. These removable sleeves have the advantage that they may be readily replaced when worn, may be cleaned readily, and may be changed for others with different inner surfaces for different uses. The outer case may then be in one piece. When the rotor is a plain or ruled cylinder the sleeve need not be split.

As shown in Figures 1, 2, and 3 of the drawings, the distance between the grooves of the rotor and casing gradually diminishes from the inlet to the outlet, from say about 0.1 to 0.001 inch,'so that larger suspended particles entering the mill are continuously disintegrated as they flow around the rotor. This graduated spacing is accomplished by machining the grooves in the left hand side of the ease with any desired diameter larger than that of the rotor and of the grooves of the right hand side of the casing, the latter being closer to the surface of the rotor itself. As these machines are best made in standard sizes, the left halves can be bolted together and machined to make the grooves as desired, particularly so that the grooves at the lower portion of the right hand side of the casing will form a continuation of the grooves at the lower portion of the left hand side of the casing, when the two halves are assembled. By the arrangements shown in the drawings and discussed above, the distance between the rotor and the portion of the casing nearest to the rotor, can be adjusted as desired. Two right halves of the casing can also be bolted together to machine the grooves therein with any desired diameter compared with those of the rotor. The right half of the casing shown in Figure 3 may have exactly the same diameter for the grooves as has the rotor. Or the diameter may be slightly larger with the diierence used as spacing between the rotor and casing at the bottom, the top and upper right hand sides of the rotor and casing fitting very closely. These same methods are used with the plain cylinder rotors and casing described below.

In Figure l there is shown an inlet 22 and an outlet 23, formed by means of openings 24 and 25 in the right hand portion of the case, the inlet preferably containing a strainer (not shown) to prevent the entry of large objects, and while these inlet and outlet openings may be of the same size, it preferable to make the outlet somewhat larger in diameter. 'I'he upper portion of the right hand side of the casing is prefer-` ably separately machined to form a continuation of the grooves in the left hand side of the casing. That portion of the right hand side of the casing which lies between the inlet and outlet openings preferably fits very close to the rotor so that no liquid may pass into the inlet after the material has passed around the rotor, For similar purposes that portion of the casing between the openings 22? and 23 shown in Figure 3 is similarly placed close to the rotor for similar reasons. If desired the portions of the casing 26 and 26 respectively in Figures 1 and 3 may be made as separate plungers, rectangular or otherwise in shape, fitting closely to the rotor and arranged with springs and levers or wedges or screws at one or both ends or the center thereof,

to press the portions or gates 26 or 26' against or 150 as near as desired to the rotor to allow for variations in the position of the rotor when adjusted as set forth above. The centrifugal force exerted on the particles of the material under treatment causes practically all of the liquid to fly off the rotor into the outlet, while the liquid entering through the inlets cannot, even when under pressure easily flow under the gate because of the opposing pressure exerted at the high speed. The outlet may advantageously have a baffle 30 running its length as shown in Figure 3 and so situated that the liquid flying from the rotor at high speed strikes the baille and causes disruption of the particles by the impact. -The two halves of the casing may be separated by a gasket of paper, metal. or other material as shown at 27 and 27', of any desired thickness, and by variation in the thickness the distance between the rotor and the case may obviously be varied. For further adjustment, the case or either half thereof may be raised or lowered by means of screws, wedges, 0r shims, placed under the halves of the case. By these means. the case can be Separated as desired from the bottom, sides or top of the rotor.

The roller or ball or other bearings fcr the shaft may be housed in separate standards outside the case as illustrated in Figure 2; or it may be cast or made integral with one of the halves of the case, as on the right side of Figure 1 where the distance between the rotor and case may be advantageously fixed. But the bearing housing may be adjustable in position if desired to space the rotor from the bottom, sides, ends or top of the case.

Another feature of the disclosed machines 1s that they may be used as low speed grinding mills. In this connection attention is called to the fact that in making the very perfect nuts and screws for ruling engines, dividing engines, etc., the split nut can be run backward and forward over the rotating screw with a proper cutting lubricant whereby the threads can be made to fit so perfectly that longitudinal movements and measurements within about 0.000,01 millimeter may be made. By employing this principle of machine cutting, the grooves in the case and rotor may be made to fit each other very closely, and by then pushing the desired portion of the case against the rotor while the latter is rotating, and employing suitable grinding and lubricating materials, the surfaces of the grooves can be made to t each other as perfectly as desired. In other words, the grooves in the machine are self grinding or self adjusting over the entire length of the case 0r rotor. In an analogous manner the right hand and left hand portions of smooth casings may be pressed against a smooth rotor, and with the use of proper lubricants ground to fit as closely as desired. 1n all of these cases, the particles passing through the mill receive the same degree cf grinding action with consequent dispersion. The amount of heat generated by the friction of the rotor against the case is small and this friction may be prevented from generating much heat by placing a cooling medium in the jackets.

The mills referred to above may be made of any desired material suitable for the particular purpose in hand, such as hard steel, Monel metal, brcnze, etc., and the rotor or case or both may be plated with tin, lead, gold, silver, etc. when desired.

In place of using castings for the rotor and case, each may be built up to any length by using sheets of any desired metal to stamp out circular discs d with perforations to decrease the weight when desired and with central openings for slipping them over the shaft to make a built up rotor.

and stamping out corresponding cross sections cof the entire case to make a built up case as shown in Fig. 5. Threads and lock-nuts 1n on the shaft hold the circular discs tightly together like a cast rotor. The cross sections of the entire case have openings to make annular passages through them through which threaded bolts b pass to hold the sections together. By the use of proper openings for the inlet and outlet pipes. and for cooling or heating jackets. with the use of proper end plates, al1 as will be understood by those skilled in the art, the entire machine may be assembled simply, to replace the castings referred to above. The advantage of this method of construction is that the length of the parts may be increased to give greater capacity, while any sections that become worn or broken may be simply replaced. Further the machine may be easily disassembled for cleaning etc. When a comparatively smooth rotor is desired the d ses will be cylindrical. But when the rotor and the inner face of the case are to be V or sine grooved and have the relative features set forth in the drawings, the outer edge of each section of the rotor and the inner edges of the sections of the case are made to give the desired grooves when assembled. These grooves will be so arranged that the structure described above with cast sections in Figs. 1, 2 and 3 is obtained. There will be no need in this type of structure to have the casing in two or more portions as is necessary when castings are used.

The rotor shaft may be integral with, or directly connected by a flexible coupling or by a belt or gear drive to the shaft of a steam or air turbine or an electric motor. The rotor can operate either horizontally or vertically with efficiency. The larger mills for factory use with rotors 10 to 20 inches in diameter may be operated at speeds of 5000 to 10,000 R. P. M. with safety, while smaller mills may be run at even higher speeds for example from 10,000 to 20,000 R. P. M. for making dispersions of vcastor oil, milk powder, mayonnaise, malted milk, or other useful colloidal solutions and dispersions.

As indicated above, a modification of the machines set forth above is obtained by omitting the grooves in the rotor and case and thereby converting the rotor into a cylinder rotating within a case which is wholly or partially cylindrical and whose inner surface is either concentric with the rotor or has a varying position relative to the surface of the rotor, as shown in Figures 1 and 2; for example, a decreasing distance when passing from the inlet to the outlet. Larger particles coming into the wider clearance are crushed into finer ones which pass on further and are crushed again and finally by attrition among themselves and against the walls and between the liquid lms are broken down into colloidal size. A distinct addition to the effectiveness of such action is provided by sand blasting or ruling lines on the rotor and case either parallel to the axis of rotatlon, crisscross as in Fig. 6 or spirally as in Fig. 4. These lines may be of varying depth and distance apart such as from 1 micron to 0.001 inch or more. And the relation of the width of the grooves to the depth, as well as the angles made between the sides of the groove and a radius drawn to the bottom of the groove, can be varied at will to suit the particular substance which is to be broken down into colloidal condition.

When, as in Figure 4, the rotor and case are concentric, the case or rotor or both may be conlcal for about one inch, and the surfaces may be smooth, roughened, grooved, or ruled. The liquid may be forced through by a suitable pump and will pass in at the one end i, spirally through the machine, and out at the other end O. The liquid is thus subjected for a longer time and distance to the centrifugal and disrupting forces with resulting greater disruption. Since in the ordinary construction, the inlets .and outlet extend for the same length more or less as the rotor, if desired, one portion of the inlet may be closed, and a corresponding portion of the outlet closed, so that the liquid must traverse a spiral path through the machine by entering and leaving the ends, where for example the case or rotor or both are conical as in Fig. 4, thus increasing the disruptive action due to the increase in time that the material will remain subject to the action of the mill.

One marked advantage of these different embodiments of the capillary colloid mill is that the enormous centrifugal forces always throw the liquid outward into the casing and that the liquid does not flow out at the ends of the casing and rotor. With the grooved rotor and case, the liquid nows in the grooves and with the smooth or ruled rotor and case, a small shoulder in Fig. 2 causes any film escaping between such shoulder and rotor to be thrown outward until it reaches the outletf If however the liquids are forced into the mill to increase the capacity, sunicient pressure can be applied to force the liquids out at the end of the rotor and case and in such event, end plates p are attached as shown in Figure 2 to prevent loss. 'Ihe use of soft gaskets in a stuning box b, allows the case to be moved in the bed plate grooves a few hundredths of an inch, which is sufncient for making the require'd adjustments as a general rule. l

When the liquids are pumped through the mill with increased velocity to increase the capacity, there is also increased kinetic energy in the suspended particles as they strike the containing wall and hence greater disruption. While forcing the liquid through the mill, the rotor may be turned in a direction opposite to the flow of the liquid, thereby producing greater disruption but smaller capacity.-

If still greater centrifugal and disruptive forces are desired, than are practical by increasing the speed and diameter of the rotor the case can also be made to rotate oppositely to the rotor. The case bearing can be arranged on the shaft of the rotor or the rotor and case may each have two or more bearings on one side. The inlet and outlet of the case may conveniently connect with a hollow shaft, equipped with portholes and receiving slip collars for allowing liquid to flow in and out through the nlm space.

This colloid mill can be used not only for making colloidal solutions but for spray drying of similar solutions or other materials, and this is one of the novel features of the present invention, particularly for making dry colloidal powders. By leaving the cap on of the outlet of the mill in Figs. l and 3 the colloidal solution will emerge in the form of a very nne spray or mist, each little drop of which contains comparatively few colloidal particles. By passing this mist, preheated when desired, into a vacuum, or into a. stream of heated air or other fluid, in closed chambers the liquid is evaporated and the few colloidal particles form a small mass. The colloidal solution and the dried colloid powder may or may not have added to them a stabilizer or protective colloid such as galactan, gum Arabic, glue, etc. Milk, fruit juices, colloidal polishing materials, colloidal dyes, rubber latex, and numerous other materials as well as mixtures containing them, may be dried in this way. For example sulphurcarbon disulphide solutions dispersed in water, can well be made up in this way. The colloidal powder is collected in settling chambers or by means of screens or by electrical precipitation and the evaporated solvent may be condensed out of the air stream by cooling coils, etc., the air again being used cyclically in the process. When the colloid powder is glutinous like dispersed rubber-sulphur-accelerator-pigment mixtures, the settled powder may form a cohesive mass. But when the particles are surrounded with a stabilizer, such as milk powder, the colloid mass may be shipped and then` taken up in the solvent and dispersed again, especially with the colloid mill.

But the use of these high speed cylinder and cone type colloid mills herein set forth are particularly claimed in making colloid spray dryers. By omitting from the China and Fornander and similar cone mills the housing used to receive the colloidal solution after it passes through the nlm space between the cone and its seat, the nlm of colloidal solution is thrown into the air as a mist as in Fig. 6. Such a cone mill for spray drying should be preferably provided with the bearings and shaft on one side of the cone only, and the solution should now from this side through the film space so as to emerge into the open air as a hollow cone of mist without striking any further parts of the colloid mill. Running air at a with the liquid at i through the nlm space gives a nner mist and smaller colloid masses.

This type of spray drying gives a fine product and the capacity is much higher than is obtained in spray driers containing single small orinces through which the liquid is pumped at high pressure into a heated air stream.

Although this principle of capillary colloiding gives highly dispersed colloids comprising liquids, waxes, and solids, it has been found to be particularly desirable to combine such processes with the regulation of the physical and electrochemical properties of the solution such as viscosity, surface tension, and concentration of hydrogen, hydroxyl and other monoand polyvalent anions and cations such as sulphate, phosphate, calcium, and aluminium, in order to nx the nature (positive or negative) and extent of the electrical charges on the colloid particles, their contact potential difference toward the solution, their mobility and their tendency to repel each other and remain stable or to come together or nocculate into larger masses of colloidal particles which settle out of solution. By the use of hydrogen electrodes, cataphoresis apparatus, and buffer materials etc., I can easily regulate all these factors and hence the properties of the colloid solutions and make them remain stable indennitely with the particles in vigorous motion or pass through various smaller degrees of stability and mobility and finally lose practically all electrical charges and motion, and nocculate out. Portions of the colloidal particles may be nocculated fractionally, or all of them may be nocculated, and the solution clarined.

The properties of these solutions can hence be regulated as desired with reference to other colloidal or true solutions with which mixtures are to be made. In particular the colloidal particles may be charged positively or negatively and given mobilities from practically zero to as much as the usual anions and cations of elements or compounds (excluding hydrogen and hydroxyl ions); namely about 3-7 microns per second per volt centimeter drop in potential when electrolyzed at about 25 C.

This colloid mill is highly efficient for disruption of liquids, waxes, semisolids, occulated masses and solids suspended in aqueous and alcoholic liquids, petroleum, and other liquids. The particles may be varied in size with the different materials, depending upon the intensity of the forces applied, the distance between the rotor and the case, the volume of the material passed through the mill per hour, and the electrochemical conditions of the solution. But the particles can be made small enough in general to show Brownian movement and vary from about one micron (0.001 millimeter) in diameter downward, while all of the particles exhibit uniform electrochemical properties. This mill is efiicient for changing an oil-in-water emulsion to a water-inoil emulsion with change in the electrochemical conditions of the solution. It is suitable for intensive mixing of insoluble materials; e. g. tne dispersion of coal in crude 'heavy petroleum oils to make a liquid coal fuel, or graphite in lubricating oil, or the re-dispersion of flocculated aluminium hydroxide which can be broken up into the component colloidal particles in oil-inwater emulsions or Western larch galactan-tannin extracts and allowed to reflocculate at a hydrogen ion concentration of about P11258 and bring down the oil or tannin materials and clarify the (galactan) solution. It is useful for intensive mixing of alkalies or acids with oils from which acid or alkaline constituents are te be extracted and settled olf in the aqueous solutions. It is suitable for treating old newspapers with oils or clays like bentonite in water to de-ink the paper while separating the fibers and rendering them suitable for making paper again. It is useful for intensive washing of impurities from very small crystals by means of suitable solvents, the small crystals then being separated out by a gravity centrifuge or filter. It is especially useful for disintegrating slowly soluble materials in a liquid into extremely ne particles which dissolve more rapidly. By having two or more inlets any given mixtures can be formed, such as a colloidal precipitate from two true solutions which can then be intensively mixed with another material such as a protective colloid like galactan for stabilizing the first colloidal precipitate. Any number of consecutive reactions of true or colloidal solutions can thus be made to take place at desired very short time intervals. 'I'he mechanical, chemical, and electrical forces taking part in these processes are rigidly controlled by these methods.

The mills described above as a feature of this invention present many advantages over known mills. The liquid leaves the disrupting region in a film whose cross section parallel to the shaft is a straight or a corrugated line which may strike a baille plate in the outlet at high velocity and disrupt the suspended particles still further. This line may be as long as desired and therefore increase the area and capacity of the single opening of the Gaulin homogenizer.

This mill is so arranged in Figs. 1, 2 and 3 that the line of flow is practically always in a plane perpendicular to the shaft. As a result the centrifugal forces and the forces (kinetic energy) causing disruption which come into play when the path of a particle is continuously diverted from the tangential to the radial or circumferential are all in a plane perpendicular to the shaft and therefore at a maximum. The case may be regarded as having a comparatively very thin liquid film on its surface and the rotor as having a film on its surface which move with high velocity past each other, and the intervening liquid. Such liquid films passing at high velocities such as 2 to 4 miles or more per minute act almost like solid grinders causing disruption of liquids, waxes, solids, networks of fibers, and crystals, etc., thrown by the convection currents and centrifugal forces into the regions of film shear without contaminating the solution with abraded particles of the mill metal.

The V or other shaped grooves act like capillaries when liquids or solids are squeezed into them by the centrifugal forces and such suspended material is thereby elongated and diminished in cross section and disrupted into smaller particles. This process is continued until the finest of subdivision is accomplished. The kinetic energy of the suspended particles given by the centrifugal and pumping forces causes each particle to be jammed or squeezed unto the V or sine or other grooves when the path of the particle is diverted from the tangential to the radial or circumferential. As the high speed liquid traveling in the groove sweeps these jammed particles along, a multiplicity of such jammings or impacts take place continuously around the case and cause high dispersion of the suspended particles.

The minute disintegration of solids or liquids in liquids brings about intimate contact and mixing and reactions otherwise requiring too much time and material. This mill is therefore useful, especially with electrochemical regulation, in all of the following classes of processes.

Carbons. clays, cellite, silica gel, etc., are dispersed in turbid, oily or aqueous solutions requiring clarication, reach all particles thereof efficiently in a way not possible with coarser decolorizing materials, and upon proper electrical regulation occulate out with the impurities.

Different types of china and ball clays, flint, feldspar, etc. can be homogenized and converted into uniform mixtures for the pottery or tile manufacturer.

Photographic emulsions, mica colloidized with rubber and paraine or other waxes to form a dielectric for condensers, and rubber and parafline and vaseline dispersions for condensers and lubri- 1f cants and salves are easily made.

Carbon black with or without added dyes may be homogenized in oils to make printers ink.

Flavoring extracts and perfumes are dispersed and dissolved in alcoholic and aqueous suspensions.

Powdered milk with or without added butter fat or oleomargarine, oils, etc., gelatine, albumin, etc., may be homogenized into milks and creams and icecreams, together with dispersed air when desired.

Various hydrogenated and natural vegetable and animal oils may be dispersed hot and cooled quickly to form homogeneous lards and butters.

Malted milks, chocolate, orange flavors and other materials may be dispersed to form soda fountain drinks.

Oxides of magnesia, zine, aluminum and the like are simultaneously dispersed and hydrated to form milks or creams.

The homogenization of immiscible liquids such as aqueous or acid or alkaline solutions and benzol, gasoline, creosote, rancid peanut oil and vegetable oils, allows washing and removal of acids, bases and other impurities or constituents which may be recovered.

The intensive mixing of crystals containing adhering oily or solid impurities with solvents capable of dispersing the impurities into colloidal solution leaving the crystals pure is carried out in this mill with great emciency.

Dispersions of paints and stains in oils or water with stabilizers such as suspensions of zinc oxide. barium sulphate, lead oxide, lead sulphate, iron oxide, whiting, etc., and organic dyes and stains in linseed oil, sh oils, creosote, etc., or in water with stabilizers such as glues, albumins, galactan, etc., are suitable for painting and staining woods, shingles, metals, etc.

The dispersion of nitrocellulose, cellulose esters, natural and articial gums like damar, kauri, coumaron and also appropriate coloring matters in solvents like ketone oils, amyl-acetate, diacet-one alcohol, ethyl acetate, benzol and mixtures thereof make excellent lacquers, varnishes. etc.

By using albumins, glues, dextrines, western larch galactan, gum arabic or other protective colloids like oleic acid compounds, sulphonated animal or vegetable oils or other stabilizers with regulated electro-chemical conditions and employing water, animal or vegetable oils, organic or inorganic solvents, etc. a wide variety of dispei-sion suitable for foods, fuels, cleaning agents, medicines, industrial solvents, etc., may be made, such as mayonnaise dressing, graphite suspended in lubricating oils or emulsions thereof, colloidal coal dispersed in fuel oil with a stabilizer, liquid soaps, colloidal inks in oils or water, shaving creams, tooth pastes, ointments of all kinds, vaselines, leather and belt dressing, etc.

The mill is excellent for the disruption of masses of ne or colloidal particles like clays, diatomaceous earth, fullers earth, iron oxide, chalks, maris, rouge. ores in mineral flotation, cement, cellite etc.

'I'he mill disintegrates, and forms aqueous, alcoholic, or oily extracts of, vegetable cells like yeast, bacteria, starch, plant tissues like tan barks and woods, lemon peel, ginger, cinchona bark, coee, etc. The fibres or cell walls settle out and leave the extracted materials in colloidal suspension. If desired the pH value and other electro chemical properties can be regulated so as to flocculate or dissolve any portions of the extracted material or of added constituents and form extracts of desired properties such as invertase from yeast.

In the same way extracts can be made oi' all kinds of meat tissues, etc. in the cold without coagulation of proteids or in hot solution involving such precipitation.

Emulsions of castor oil, cod liver oil, mineral oil, olive oil, malted milk, and many other mediciv nal suspensions with stabilizers are easily made.

Dispersions of waxes such as paraine, rosin, beeswax, carnauba wax, ozekerite, asphalt, pitch, and the like are made in this mill and used as waterproof coatings or sizings for paper, cloth, linoleum, concrete walls, walks, floors, roads, etc.

Insecticides, fungicides, and disinfectantsare made by forming colloidal suspensions of calciumA or other arsenates, Paris green, Bordeaux mixture, creosotes, etc., with stabilizers or oils or both at pH 8 or 9 for example and using them as sprays or dips lfor plants or animals or cross ties, poles. posts, etc.

The niill can be used for beating pulp to separate the libres and wash out the pulping chemicals; for disintegrating old newspapers and other waste paper with solvents or bentonite under regulated electro-chemical conditions to remove ink and oils from the ,bres which are thereby converted into a pulp stock suitable for use again: for the uniform beating and mixing of rag stock; for the uniform dispersion of the rosin, barytes, casein and other constituents of paper sizing under electro-chemical regulation such as at pH value about 8 to 9 to keep the negative rosin and other colloidal particles in active Brownian motion ancl` stability while making and keeping the sizing and yet allowing these particles to precipitate out on and coat the paper fibres uniformly when applied thereto in the paper making machinery.

The mill can be used for softening old rubber tires, or other waste rubber, with a solvent like naphtha and dispersing this softened rubber in water with a regulatedgstabilizer like albumins, gums, casein, glues, soaps, etc., separating the rubber emulsions from any fibres, and heating this artiilcial latex or emulsion with 5-10% alkali at -150 pounds steam pressure 5-25 hours to remove sulphur and devulcanize or reclaim the rubber, which is precipitated and then washed free of the chemical solutions. The alkaline liquor is evaporated, incinerated, dissolved, limed, ltered and treated to recover and reuse the alkali. The mill may be also used to homogenize the artificial or natural rubber latex with sulphur, iron oxide, antimony sulphide, accelerators, carbon black, zinc oxide, etc., under regulated electrochemical conditions such as at pH 9 and with colloid mobilities from 4 to 6 microns per second per volt-centimeter drop in applied E. M. F., and then vulcanized in solution and spray dried or coagulated, or first spray dried or coagulated and then vulcanized, and used for making rubber articles.

'I'he mill can be used for making clay castings 120 and reclaiming waste castings by regulation of the electro-chemical conditions as follows. The

clay mixture is roughly disintegrated into about 25 mesh material and dispersed in this colloid mill or broken up in a grinding mill in water 1'25 into a uniform suspension. 'Ihe pH value and colloidal mobility may vary with the kind of clay used, with its tendency to change from the sol to the gel form, with the details of the processes employed subsequently, and with the objects to be made. pH values 7.4 and 8.0 represent those used in this process in two plants. By adjusting this clay mixture with acetic or other acid, or with an alkaline carbonate or hydroxide if necessary, itis easy to get a pH value best suited to the subsequent work. This adjusted clay suspension is then screened to remove larger objects, and then lter-pressed to remove the water down to around 22-30 per cent. 'I'his wet clay is then treated with the feldspar and flint if these were not added originally and with sodium silicate and alkali to form a clay slip containing about 22-30 percent of water and having a pH value such as 7.5 to 8.5, depending upon the clayand further use. 'Ihis slip is largely in the sol form and drains and flows readily and is run into plaster of Paris or other moulds to remove water and other soluble constituents and form articles such as wash bowls, electrical xtures etc. These partly dried objects are allowed to stand or are passed through 1:3

heated drying rooms to dry thoroughly and set the clay gel and are then baked. During these processes the castings often crack and cause considerable financial losses unless the above electro-chemical conditions have been regulated properly, and there may be further losses in the subsequent stages of firing and glazing. By such electro-chemical regulations a higher plant yield of objects of better color, toughness, and durability can be obtained. By'these processes it is possible to use the waste clay castings. It is only necessary to use these castings alone or in mixture with fresh clay and grind them together While regulating the pH value to the desired point by adding acetic or other acid to change the set" gel back to the sol form and to adjust the alkalinity arising from the silicates and other basic materials in the waste clay scrap. In this electro-chemical regulation the alkalinity of both the water and of the waste or fresh clay varies so much that the addition of fixed quantities of acid for all clays and water will not suffice; sufficient must be added gradually to give the definite desired pH value to each plant batch when tested properly by colorimetric or electrometric methods. By the use of these processes uniform pottery practice may be had even though the water and the exact composition of the clay and clay scrap may vary from time to time and cause difculties without such electrochemical regulations.

This mill is especially useful for forming an emulsion of a preservative such as a creosote from coal tar, wood tar, or water gas tar. By passing a mixture of creosote and a soap solution of '1-5 percent of rosin soap, sulphonated sh oil or castor oil soap or other stabilizer, through the mill while adjusting the pH value of the finished product to 8.5 to 9.5 the creosote is dispersed into particles all of which are in vigorous Brownian motion and with diameters 1-2 microns or less and with stability and a mobility of about 5-6 microns per volt centimeter E. M. F. at 20 C. This creosote can be boiled or frozen without appreciable occulation. The percent of creosote in the emulsion may vary widely, say from 1-95 percent. It can be used with very great advantage and economy in replacing straight creosote for impregnating ties, telegraph poles, paving blocks, timbers and the like by spray, vat or pressure cylinder methods. For example, by compressing air into the dry ties in a ,pressure cylinder at 15 pounds and then forcing the hot creosote emulsion under 100 pounds pressure into the ties, the creosote particles penetrate several inches into the wood and are deposited on the fibre walls and coat them thoroughly to prevent the growth of fungi and bacteria therein. The aqueous suspension medium and residual creosote particles are forced out ofthe ties by the compressed air therein when the pressure is slowly removed from the cylinder and the creosote emulsion is pumped out. By applying a vacuum gradually to the cylinder the last portion of the emulsion is removed from the wood. This recovered emulsion is used for dispersing more creosote therein when desired. Obviously the variations in the technique can be used to correspond to standard practices in individual plants. The ties are allowed to air dry or may be kiln dried to remove the water without cracking and are then ready for use. Obviously this emulsion may be used to treat other porous materials such as concrete walls or piles or blocks and the like, the pH value being properly adjusted not to injure the concrete while at the same time causing the deposition of the creosote particles. The creosote may be mixed with toxic materials like copper arsenate compounds, zinc chloride, sodium fluoride, chlorinated phenolic and amino compounds, coal tar, bitumen, asphalt or other desired ingredients which are thoroughly dispersed with the creosote particles in the emulsion. The treatment with the creosote may also be coincident with or alternate with water proofing, fire proofing or rubberizing or other treatments to give the wood, concrete etc. other desirable qualities. For example, a mixture of creosote and natural or artificial rubber latex can be made as a stable emulsion with colloidal sulphur and an accelerator to vulcanize the rubber after it is deposited on the cell walls with the creosote, the treated wood being thereby preserved, Waterproofed and toughened. Solutions of borates, phosphates, arsenates and the like can be forced into the wood as a part of or separate from the creosote emulsion and after the removal of these solutions from the wood another solution containing compounds of aluminum, copper, zinc or other desired materials can be injected into the wood to form insoluble fire proofing, disinfecting, borates, arsenates, hydroxides and the like which coat the wood fibres. The excess solution is then removed from the wood. By adjusting the electro-chemical conditions properly fairly stable colloidal suspensions of such' insoluble borates, arsenates, and the like can be made with the mill and then injected into the wood and allowed to floceulate out on the wood fibres, the excess solution then being pumped from the wood as described above.

By way of illustration of the methods of electrochemical regulation of solutions, mucic acid can be chosen as a buffer material. When treated with alkali to give increasing amounts of the acid salt and then of the neutral salt per molecular weight of mucic acd in a given volume of solution, there is both a decrease in hydrogen ion concentration, CH, or increase from say 3 to 6 in pH value (pH equals login (l/CH) and an increase in the concentration in the hydroxyl ions all of which ions are available for reactions and for absorption by colloidal particles. The relative concentrations of the hydrogen and hydroxyl ions and their coefficients of absorption by the dispersed phase determine the amounts of separate ions absorbed by each unit colloidal particle and 125 the nature (positive, neutral or negative) and the magnitude of its charge. It is therefore possible by pH regulation to give the particles of some types of materials any desired degree of positive or of negative charge, especially if the 130 coefficients of absorption of the hydrogen and hydroxyl ions are large. The neutral particles have practically no Brownian motion, which results from mutual repulsion of moving charged particles, and such neutralized particles slowly 135 combine and flocculate out of solution. Particles with increasing positive or negative charges increase in mobility up to 3 to '7 microns per second per volt centimeter drop in applied E. M. F. and its stability or lack flocculation in the solution increases.

But other monoand polyvalent ions and the molecules are also absorbed along with the hydrogen and hydroxyl ions in aqueous solutions and can be therefore made to assist in charging or neutralizing the colloidal particles while keeping the pH value at any desired figure to regulate other properties of the solution. For example, trivalent aluminum cations or phosphate anions can be used to add large numbers of positive or 150 negative charges to particles or to neutralize opposite charges. Similarly, calcium, sulphate, arsenate, phthalate, tartrate, sulphonated fatty acid ions and any other cations and anions can be used. By varying the degree of neutralization of any polyvalent base or acid the colloidal particle can be surrounded by different concentrations of the free base or acid and of the acid .or basic salts and of their ions and of the neutral salts and of their ions, all of which are absorbed in Varying degree and contribute to the electrical and physical properties of the colloidal particles and of the entire solution. Furthermore, neutral or ionized protective colloids like western larch galactan, gum arabic, rosin soap, sulphonated castor oil or ilsh oil soaps, vegetable oils, etc. may be added at the same time to form a coating or layer around the colloidal particles to adsorb the surrounding ions and chemicals and to increase or decrease the stability. Naturally the concentration of the buffer materials and of the protective colloidal materials can be increased while keeping the pH value or other electric factors at ilxed values or at desired variable values. By all of these methods we can control separately and collectively each one of the important factors of contact potential between the particles and solvent, surface tension, electrical conductivity, osmotic pressure, nature and degree of electric charge on the colloidal particle, pH value, viscosity, mobility of the colloidal particles, size of the colloidal particles produced by dispersion, etc.; and we can thereby regulate the variable properties of both the dispersed phase and the dispersion medium of widely different liquid and solid colloidal solutions. All these particles have an effect not only on the size of the particles that can be formed by dispersion in this and other colloid mills but on the properties thereof after dispersion. By the methods of operation and control I not only determine and regulate the properties of the colloidal solution itself but also the relation of such properties to the materials to be treated therewith. For example, I can regulate the properties of two colloidal solutions that are to be mixed without fiocculation on the one hand, or with resulting occulation on the other hand when the charges on all the positive or negative particles are practically neutralized. Or I can properly control the properties of colloidal solution extracted from, or used to coat or impregnate, solid or fibrous products; for example, coating automobile tires and rainprooiing fabrics with rubber emulsions or impregnating cross ties, telegraph poles, or the like with a creosote emulsion, or makingextracts from various vegetable and animal tissues.

An example of this last process is the extraction of galactan from western larch. When the western larch chips and sawdust are extracted with water an aqueous mixture of galactan and tannin and perhaps other materials is obtained. If the chips or aqueous extracts are heated at -125 C. in solutions containing 1-2 percent of sulphuric acid, that is at a pH of about 1.7-1.4 or below, together with a decolorizing carbon or clay or silica gel or other similar agent when desired, the tannin and other coloring matters are ilocculated and can be easily filtered. 'Ihe ltrate contains the residual galactan and also quantities of galactose and other materials formed by hydrolysis of the galactan and other constituents of the wood and extracts and by further heating all of the galactan can be converted to galactose. When it is desired to obtain galactan in the form of a solution or solid gum without contamination with the hydrolysis products (galactose etc.) or with tannin materials the aqueous larch extract is treated with about 1 percent of charcoal or bentonite or 'silica gel or other decolorizing agent when desired and with aluminum sulphate or chloride. 'I'he amount of the aluminum salt may vary froma few parts per million to a few parts per thousand of solution depending upon the amount of tannins and colloidal material to be removed. 'I'he pH value of theentire solution is now adjusted to cause the occulation of all the tannins, colloids, carbon or other decolorizing agent, and of the aluminum as hydroxide. Instead of an aluminum salt, fiocculated aluminum hydroxide may be used as such and dispersed into the galactan solution by means of the colloid mill to adsorb the tannin and other materials. The best pH for the occulation of the aluminum hydroxide is about 5.8 but the adsorption of other positive or negative ions or molecules of various materials by the normally positive aluminum hydroxide may cause a variation of ya few tenths one way or the other, depending upon the concentrations and adjustment of all the materials concerned. When the flocculate is filtered off a clear, colorless solution of unhydrolyzed galactan is obtained with practically no soluble inorganic impurities. By evaporation of this solution under vacuum or otherwise to prevent decomposition a thick tay or solid can be obtained, which can be used as such or treated with alcohol to form a white powder. The galactan in solution is useful like gum arabic, etc., as a protective colloid to form stable emulsions of oils or solids, as an adhesive, and as a coating for mucic acid and the like in baking powder to delay their action with sodium bicarbonate. l 'Ihis mill and these processes are also useful in making electrolytic condensers and alternating current rectifiers and the like. When two plates of aluminum, iron, copper, tantalum or lead are immersed in iiuid or gel electrolytes m such as adjusted phosphate, borate, arsenate, etc. buffer solutions and an electric current is passed alternately from metal to metal a deposit of aluminum hydroxide, ferric hydroxide, etc., is formed as a dielectric film on each plate. The cacapcity of the condenser and its constancy can be regulated by the adjustment of the pH and other electrochemical factors as follows. The solubility of the aluminum hydroxide film varies with the pH and the amount of positive or negam tive ions adsorbed from the solution. At a pH of 4.5 to 6.5 and especially at about 5.8, the capacity is comparativelyY constant because the film is very insoluble; but it dissolves slowly in a solution having a pH of 9 or 10 and the capacity is V1M thereby increased when desired; e. g. from 0.1 microfarad per sq. cm. surface to several times this value. By keeping the pH value adjusted at the point of least solubility or most constant capacity of the film very satisfactory condensers can be made with manyfold the capacity of paper or mica condensers of the same metal surface and with a breakdown voltage of 500 volts or more, depending upon the applied E. M. F. when the films are formed. As the solution gradually becomes cloudy from the disruption of colloidal particles from the lm and these charged particles migrate with the current to and from the iilm,thecolloidmillcanbeusedtodispersethem illm material such as aluminum hydroxide in the electrolyte and thereby saturate it before use for forming and connecting the nlms on the plates. By this regulation of the pH value I can use comparatively dilute electrolytes such as l-2 percent or less, with great advantage and with small power losses such as 2-5 percent. Excellent rectiflers can be made for changing an alternating to a direct current for charging storage bat. teries and for furnishing the grid and lament current for radio installations and the like. This is done by using a Nodon valve arrangement with lead and aluminum plates immersed in a phosphate or other suitable electrolyte with adjusted l5 pH value between 4 and 6. It can also be done (1) by forming a cell with lead and aluminum plates in succession and connecting all the lead plates as one electrode, and then connecting alternate aluminum plates to form two other electrodes 2o comprising two sides of a Nodon valve; and (2) then using two equal inductances or choke coils to replace the other two sides of a Nodon valve, the direct current connections being made at the lead plates and at the Junction of the choke coils, and the alternating current connections being made at the other two corners, by drawing off the above described direct currents through a series of inductances in parallel with capacities of proper values to sift out the overtones, it is possible to obtain practically a pure direct current of desired voltage and amperage. By using an interrupter with a 60 cycle alternating current and thereby producing frequencies above the audible range and rectifying such high frequencies, the pulses in the direct current are above audio frequencies and do not disturb the'use of such direct current in place of A and B batteries in radio communications. The same object may be accomplished by rectifying the cycle alterz i nating current and converting this direct current by means of an inductance, a condenser which may be an electrolytic one with regulated electrochemical conditions, and a DeForest tube back into a sine wave alternating current with fref quencies below or above audible ranges, and then rectifying this alternating current by means of an adjusted rectifier of the above types. Such a rectified direct current may still have pulses if not filtered as above, but such pulses will be g; outside the audible range and will not be heard when used for lament and grid currents.

Having thus set forth my invention, I claim: 1. A colloid mill comprising a cylindrical case with a series of parallel grooves on the inside g surface of the case, each groove being in a plane perpendicular to the axis of the cylinder and having a sharp edge between such groove and the next one, all grooves being parallel, and comprising a grooved cylindrical rotor rotating at high ;v speed in excess of 1,000 revolutions per minute, each groove of the rotor having a sharp edge between such groove and th next one, the sharp edges of the grooves of the rotor tting between the sharp edges of the grooves of the case, and t" comprising an inlet and an outlet situated approximately 300 to 330 from the inlet, and comprising two end plates and stumng boxes to enclose the liquids circulating through such mill, and comprising two bearings supporting such w shaft of such rotor and holding such rotor in any fixed position parallel to the axis of such case.

2. A colloid mill comprising a rotor adapted to be rotated at high speed, a casing enclosing said rotor, said casing approaching said rotor con- Losanna tinuously in the direction of its rotation for a considerable arc around said rotor and an inlet adjacent the portion of said arc where said spacing is greatest and an outlet adjacent the portion of said arc where the spacing is least.

3. A colloid mill comprising means to exert a continuously increasing pressure upon material simultaneously with the subjection of the material to an increased centrifugal force, and thereby and therewith to an increased shearing stress, said means comprising a rotor and shaft adapted to be rotated at high speed and a casing having an inlet and an outlet, said casing approaching said rotor more closely in the region adjacent the outlet than at the inlet, said outlet and inlet being separated by a wall parallel to the shaft and close to said rotor and adapted to prevent fine material from passing with the rotor from said outlet to said inlet and crude material from passing directly from said inlet to said outlet.

4. A colloid mill for disintegrating contained dispersions comprising a shaft and a rotor adapted to be rotated at high speed in the arc of flow of the dispersion, said rotor having grooves around the external surface thereof and a casing enclosing said rotor, said casing having sharp ridges which mesh into the grooves of the rotor, said casing having an inlet to a space between said rotor and vsaid casing and an outlet at a point removed from the inlet, both inlet and outlet being generally parallel to said rotor and shaft, said casing approaching said rotor more closely adjacent the outlet than at the inlet, and a baille wall situated parallel to the shaft and close to the rotor and between the inlet and outlet.

5. A colloid mill comprising a generally cylindrical rotor adapted to be rotated at high speed,

a generally cylindrical casing enclosing said rotor, an inlet running lengthwise the casing substantially parallel to the axis of said rotor and admitting the material to be treated to the surface of said rotor in a illm whose plane is substantially parallel to the shaft of said rotor, and an outlet parallel to the axis of said rotor and located at a point on the circumference of said casing removed from said inlet by more than 180 in the direction of rotation of said rotor, whereby said generally cylindrical casing and rotor and inlet and outlet co-act to cause the treated material to travel in circular arcuate paths whose planes are perpendicular to the rotor axis.

6. In a colloid mill, a high speed rotor, in a casing, the end walls of the casing being imperforate, and close to the rotor, the rotor being closer to the outlet than to the inlet, an inlet leading into the space between the casing and rotor where said space is wide, and an outlet leading from the space between the casing and rotor where the space is narrow, and a dam between the inlet and the outlet to prevent direct passage of the fed-in material from the inlet to the outlet in a direction contrary to the direction of travel of the rotor, whereby all of said fed-in material must travel from a wide part of the space surrounding the rotor, to and through a narrow part thereof.

7. A colloid mill comprising a cylindrical case having circumferential grooves on its inner surface, having' a cylindrical rotor with circumferential ridges adapted to mesh with said grooves on the case, and means for adjustably moving said case and rotor relatively to each other in a 150 direction perpendicular to the axis of rotation, whereby the space between the rotor and case is adjustable at its narrowest portion.

8. In a mill for producing suspensions and emulsions, the combination of a generally cylindrical casing, a cylindrical rotor within said casing and in close relation therewith, uid inlet IUU

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