US2448042A

US2448042A - Mixing apparatus

Info

Publication number: US2448042A
Application number: US502272A
Authority: US
Inventors: Miller Bruce De Haven
Original assignee: Girdler Corp
Current assignee: Girdler Corp
Priority date: 1943-09-14
Filing date: 1943-09-14
Publication date: 1948-08-31
Anticipated expiration: 1965-08-31

Description

Aug. 31, 1948. B. DE H. MILLER 2,448,042

MIXING APPARATUS Filad Sept. 14, 1943 v 4 Sheets-Sheet 1 INVENTOR B zwe De Haven Miller 7BY a.

ATTORNEYS Aug. 31, 1948. B. DE H. MILLER HIKING APPARATUS 4 Sheets-Sheet 2 Filed 5691;; 14, 1943 l/ l 1/ I 1 I ll a TQWV A'ITORNEYS fl- 1948- B. DE H. MILLER 2,448,042

MIXING APPARATUS Filed Sept. 14, 1943 4 Sheets-Sheet 3 INVENTOR BrzzpeDeHavenMlZer ATTORNEYS Aug. 31, 1948. B. DE H. MILLER 2,443,042

MIXING APPARATUS Filed Spt. 14, 1943 4 Sheets-Sheet 4 6 INVENTOR 5 firaceflelfaaen M'Jkv' ATTORNEYS Patented Aug. 31, 1948 MIXING APPARATUS Bruce De Haven Miller, Louisville, Ky., assignor to The Girdler Corporation, Louisville, Ky., a

corporation of Delaware Application September 14, 1943, Serial No. 502,272

- 1 This invention relates ,to the treatment of fluid, plastic, or other flowable material in order to effect temperature exchange thereof, or to effect a rapid, uniform and thorough dispersion of one or more ingredients in another ingredient where said ingredients are not miscible, or at least not readily miscible, as in making an emulsion, or where chemical reaction between different ingredients is desired, but at a controlled rate, or where it is desired to remove heat of reaction substantially instantly after it is produced.

This invention is an improvement in mixing apparatus of the type in which the material being processed may be continuously passed through a chamber and simultaneously mixed, agitated, emulsified, or otherwise treated. The agitating mechanism is of the rotary type and the processing may be merely that resulting from the action of the agitator or may also include temperature change, or maintenance, and/or the addition of an ingredient to another ingredient or to a mix- 19 Claims. (Cl. 259-7) ture of ingredients at the desired point or points in the path of flow through the processing chamber.

Apparatus embodying the invention may be employed in effecting nitration, alkylation, isomerization, or other chemical action in which'heat may be generated or absorbed, or for making emulsions such as mayonnaise, salad dressing, asphalt-water, paints, or the like, for incorporating a gas under pressure ina liquid, or for various other purposes.

The main object of the invention is to obtain effective, uniform and high speed mixing by means of a turbulent flow which facilitatesrapid heat transfer, maintains a substantially uniform temperature in spite of rapid internal heat production, prevents, stratification and produces other desirable results. The turbulent flow includes an alternate high and much lower velocity of flow at different points in the zone around the agitator, a tangential flow of high speed-material into slower moving-material, a heating by impact elements and various other movements and crosscurrents.

As an important feature of the invention, the agitator is rotatably supported in a substantially cylindrical chamber with its axis parallel and eccentric with respect to the axis of the cylindrical processing chamber. Also, the agitator extends substantially the full length of the processing chamber, and is provided with beating or impact elements which are not only forced through the material but also tend to whirl it around the agitator as said material flows longitudlnally through the processing zone, so that in passing through said zon the material flows circumferentially along the peripheral wall of the chamber but at varying velocities due to the wider chamber space at one side of the agitator than at the opposite one. The eccentricity prevents a annular stratification and any separating out of heavier ingredients due to centrifugal force such as sometimes occurs when a concentrically disposed agitator is employed. Preferably no scrapers are employed, as in some 08.568 scraper blades cause a bodily rotation of the material in the chamber without thorough mixing. The agitator is operated at such a peripheral velocity that the flow of the material prevents films or layers building up on the chamber wall and it has such form and arrangement and is rotated at such speed that a high degree of turbulence is produced throughout the whole of the processing zone.

The eccentricity of the shaft in respect to the chamber wall is not so great as will cause the agitator .to act primarily on the material at one side only of the chamber, leaving that at th other side relatively quiescent. The outside diameter of the agitator should be relatively large in respect to the inside diameter of the chamber and ordinarily is at least one-half of the inside diameter of the chamber. 7

The agitator preferably has a shaft which may be solid or hollow and has beating elements projecting from the periphery thereof. The shaft is preferably comparatively large and its diameter should be at least one-half the overall diameter of the agitaton' Also, the relative diameter and eccentric positioning of the agitator should be such that the outer periphery of the agitator encircles the axis of the processing chamber. The beater elements are thus comparatively short and may be of various different types but are so.

designed, positioned and proportioned that they provide passages therethrough or therebetween. Preferably they project into close proximity to, but not into contact with, the peripheral wall at the side toward which the axis of the agitator is offset, so as to get the maximum of mixing with the minimum expenditure of motive power. With the path of movement of the agitator close to the wall at one side, and with the circumference of the agitator encircling the axis of the chamber, it will be apparent that the overall diameter of the agitator should be at least onehalf that of the chamber.

By this construction and arrangement the material will have a bodily flow at a substantially higher mean velocity at one side of the agitator than at the other, and a different type and degree of turbulence will be produced at the side of the agitator where the mean velocity of the material is the greatest and radial or tangential flow is substantially prevented, than at the opposite side of the agitator, where the mean velocity of the body of the material is slower and the beater elements move the material not only around the agitator but also outward radially or tangentially 3 v by centrifugal force. In the thinner spaces the mean velocity of the material is higher in spite of the greater surface friction on the peripheral wall, because of the greater tendency of the material to flow along with the beater or impact members and in the same general direction. In the wider spaces there is a general tendency of the material to be thrown out tangentially into the slower moving body of material beyond the path of movement of said members. In the wider spaces the turbulence is the result of the different average peripheral speeds of the material in, and that beyond, the path of movement of the heaters, the centrifugal effect on the material contacted by the beaters, and the stirring action of the heaters.

In case it is desired that one or more of the fluids be admitted at spaced points in the path of flow in the processing chamber, the structure, details, location, number and spacing of such points may be varied through a comparatively wide range. The spaced inlets may be in the peripheral wall, or in the agitator, or in a Figs. 2 and 3 are transverse sections on the lines 2-! and 3-3 respectively, of Fig. 1;

Fig. 4 is a central longitudinal section through another form of the apparatus embodying further features of the invention and intermediate portions of the body being broken away;

Fig. 5 is a transverse section on the line 8-5 of Fig. 4, but on a smaller scale and viewed from the lower or drive end;

Figs. 6 and 7 are longitudinal sections on the lines 6-8 and 1-1 of Fig. 5:

Fig. 7a is a transverse sectionsimilar to a portion of Fig. 5, but showing an alternative construction;

Fig. 8 is an end viewof the lower end of the agitator, the shaft extension being shown in section; I

Fig. 9 is a development of an annular section of Fig. 8;

Fig. 10 is a central longitudinal section through a further form, an intermediate part being omitted, and

conduit in the chamber, and may be arranged in a row along the length of the chamber, or circumferentially thereof, or helically, or in scattered positions. They may be along substantially the entire length of the chamber or may be located near the inlet for the other fluid or fluids, or along the first part of the longitudinal flow through the chamber, or near the main outlet, or along the last part of thepath of longitudinal flow. Such distribution may be decided upon in accordance with the character of the ingredients going to make up the final mixture or emulsion, the reaction, if any, to be effected, and the results to be accomplished. For instance, in some cases it may be desired to thoroughly, mix, emulsify, or chemically react two or more ingredients, before adding and mixing in a further ingredient. and in some cases a longer duration of mixing may be desired after all of the ingredients have been admitted. Likewise, the number of the spaced points of admission of a final ingredient may be small or may include a multiplicity of very fine apertures.

As previously noted, the eccentric positioning of the agitator results in varying velocities of circumferential flow in the chamber. In some cases, where it is desired to add a final ingredient at a plurality of spaced points, it is preferable to have these inlet points deliver to the chamber where the velocity of flow in the chamber is the greatest, and in some cases it may be found preferable to have inlets where the turbulence of the flow in the chamber is the greatest..

The invention also involves various improvements in the details, construction, design and arrangement of different parts of the apparatus including seals for preventing leakage along the supports or driving means for the agitator, shielding the bearings from any action by the fluids being processed, the agitator itself, the means for supplying fluids to the chamber, and other features which will be noted in connection with descriptions of several embodiments of the broader invention.

In the accompanying drawings there are illustrated several of the many possible embodiments of the present invention.

In these drawings,

Fig. 1 is a central longitudinal section through a simple form of apparatus embodying certain features of the invention, the center portion being broken away;

Fig. 11 is a section similar to a portion of Fig. 10 but taken in a'plane at right angles thereto. In the construction shown in Figs. 1, 2 and 3, there is provided a processing chamber having a cylindrical peripheral wall In and end walls Ii and i2, the end wall il having an outlet it for the processed material and the end wall i2 having an inlet It for the material to be processed. The material, while being agitated as hereinafter described, has a substantially uniform rate of continuous bodily flow longitudinally through the processing zone, in addition to the annular and turbulent flow caused by the agitator. Thus successive portions of the material will all remain in the chamber and be processed for substantially the same length of time.

The inlet it may be connected to a supply pump drawing the material from a premixing tank or in controlled ratio from separate supply pipes for the diflerent ingredients, or in some cases the end wall may be provided with a plurality of inlets for the different ingredients and through which such ingredients are delivered at controlled rates and in controlled relative proportions by pumps or other forcing means. The outlet It, or a conduit connected thereto, may be provided with throttling or flow controlling means. I

If it is desired to change the temperature. of the material as a part of the processing, or to maintain a given temperature if the processing involves an exothermic or endothermic reaction, or the development of mechanical heat, or if the processing be primarily to rapidly heat or chill the material, there may be provided a jacket I! for a heattransfer medium. The annular space between the jacket and the wall l0 maybe provided with an inlet It at one end and "an outlet I! at the opposite end, which are shown as extending tangentially to said space. There may be provided a helical baiile it between the inlet and the outlet which will prevent short circuit- 'ing of the heat transfer medium'from the inlet to the outlet .and cause it to flow in a helical path around the processing chamber. Suchbaffle is not required if the temperature changing medium bea volatile refrigerant such as ammonia, or a heating medium such as steam. 7

Within the processing chamber there is mounted an agitator having a shaft 20 with end extensions or stub shafts 2i and 22 Journalled in, on, or

outside of the opposite end walls. The shaft shown in Figs. 1 and 2 may be solid, or may be '5 hollow and have end walls connected-to the shaft extensions 2| and 22 and supporting a cylindrical tube constituting the peripheral wall.

As shown, the stub shaft extension 2i is supported by a bushing23 in a socket 24 in the end wall ll, while the stub shaft 22 is mounted in a roller bearing 25 mounted on the end wall l2. The two bearings may both be of'either type and the character may be varied, depending upon the nature of the material being processed. The stub shaft 22 projects beyond the bearing 25 so that it may be connectedto any suitable source of power, such as an electric motor. To prevent leakage along the stub shaft 22 andthrough the into the processing chamber, and to prevent any of the material being processed, which may leak past the seal, from reaching the bearing25, these two parts are separated by a space 21 and provided with openings 28, which may be in the form of radial grooves or channels in the outer surface of the end wall l2. As shown, there are three of these passages, and when the axis of the chamber is horizontal, one may be below the shaft and substantially vertical, while the'othe'r two are on.

opposite sides of the inlet I4. Thus a stream of water, steam, or other cleansing fluid, may be projected through either or both of the upper passages 28 and flow around the portion of the shaft between the seal 25 and the bearing 25 and drain out through the lower passage 28 As shown, the portion of the stub shaft 22 between the seal and the adjacent bearing is provided with circumferential grooves or ridges which tend to prevent flow of material along this portion of the stub shaft and aid in the throwing oil. of material thereon, due to centrifugal action during the rotation of the agitator.

The stub shafts, bearings and seals may be of conventional form and may be modified through a comparatively wide range.

As an important feature of the invention, the agitator and the bearings thereof are eccentrically disposed in respect to the peripheral wall In of the processing chamber, and the outside diameter of the agitator is comparatively large in re spect to the inside diameter of the said wall. As illustrated, the outside diameter of the agitator is more than one-half that of the chamber and the axis of the chamber is encircled by the periphery of said agitator. As shown, the eccentricity is such that the radial distance from the periphery of the shaft to the chamber wall is cham benthe material is caused to swirl around the agitator by the impact or action of the pins and-its velocity of circumferential movement will 'be substantially greater at one side of the chamber than at the opposite side. This varying velocity in different sections of the annular chamber with agitation in both the section where the velocity is the greatest and the section where the velocity is the lowest, produces extreme turbulence and greatly facilitates the thorough and uniform mixing of the ingredients of the mixture,

' of the annular chamber and are at some distance a bodily-one at high velocity and with mixing or I stirring by movement of the pins through the material at a rate faster than that of the material. On the other hand, in the regions where somewhere about twice as great at oneiside .as

the other and the diameter of the shaft is more than one-half the overall diameter of the agitator.

The shaft 20 is provided with a plurality of beater elements which may comprise pins'or projections 30 which are preferably radial and may be. cylindrical. The pins may be arranged in various difierent ways, but as illustrated, they are in a plurality of rows extending lengthwise of the flowing to the outlet I3 at the opposite end of the there is greater clearance between the agitator and the chamber wall, the pins travel at the same peripheral speed but the material is in greater volume and has a lower mean velocity of bodily movement. As the ends of the pins or heaters are at some distance from the wall III in the region of maximum clearance between the agitator and the chamber wall there is considerable m'aterialbeyond the path of movement of the pins and each pin tends to throw material out tangentially from its path into said region of maximum clearance. Thus, in the wider space the material is mixed by the stirring action of the pins, the centrifugal action on the material in the path of the pins, and eddying of the material which is beyond the path of the pins. The alternate high velocity and lower velocity and the resulting turbulence caused by the interaction of the different types of flow result in an extremely effective and uniform mixing in a comparatively small apparatus and while there is a fairly uniform rate of longitudinal flow of the turbulent mass from the inlet to the outlet.

The apparatus parts are all simple in design, rigid in construction, and readily taken apart for cleaning. Any suitable source of power may be employed and connected to the shaft 22 for rotating the agitator. The speed of rotation will vary with the character of the material treated as well as the shape and relative proportions of the various parts. It has been found that with a peripheral speed of at least 300 ft. per minute, the desired results may be obtained. As an example, the chamber may have an internal diameter of 24 inches and the agitator an outside diameter of 1'7 inches. A rotation of the agitator at 400 R. P. M. will give a peripheral speed of about 30 ft. per second for the outer ends of the pins. The speed should not be so great as would create a vacuum adjacent to the shaft or in the rear of the beater members, but whether or not such a vacuum might be produced would depend to some extent upon the pressure employed in the processing chamber. Where volatile ingradients are employed, the pressure may be high enough to prevent any volatilization within the chamber. On the other hand in some cases it may be desired to deaerate or remove volatile constituents while agitating, mixing or processing, and in such cases the chamber may be operated under vacuum.

In Figs. 4 to 9 inclusive, 9. further form of apparatus is illustrated and additional novel features are incorporated, which are not shown in Figs, 1, 2 and 3. In Fig. 4 there are shown the top, bottom, and a middle section or the apparatus. The portions between the middle section and the top and bottom sections are omitted to indicate that the chamber may be 01' any desired length in respect to the diameter and other proportions shown in Fig. 4. In this iorm, the apparatus is so arranged that the axis of the shaft and the processing chamber are vertical rather than horizontal and means are provided for the admission of one or more fluids to the chamber in which the material is being processed, and means are provided for protecting the seal and bearings 01 the agltator in case any of the ingredients employed in making the mixture or emulsion are of acidic or other character which may adversely affect a bearing or seal. In the construction illustrated, the processing chamber is formed of a vertically disposed cylinder 35 with top and bottom heads 35 and 31. Surrounding the peripheral wall of the chamber is a jacket 86 providing an annular space for refrigerant or other temperature changing medium. The jacket 35 has

annular headers

35 and 40, which in turn have outlet and inlet connections 4! and 42 for the temperature changing medium, which may be hot water, steam, brine, liquid ammonia, freon. or the like. If such medium be volatilized in the jacket the liquid level thereof may be maintained in any manner well known in the art, ii, that be desirable.

The agitator is of the same general type as that hereinbefore described and includes a comparatively large eccentrically mounted shaft 43 having pins 44 projecting therefrom. The relation between the sizes of the shaft and chamber,

the degree of eccentricity and the spacing between the ends of the pins and the peripheral wall at the wide and narrow sections may be about the same as shown in Figs. 1 and 2.

The upper end of the agitator has a stub shatt 45 which is mounted in a bearing 45 in the head 36, and the head has an annular flange 41 projecting into a socket 52 in the end of the agitator shaft 48 and serving to support a rotary seal including a carbon ring 45, a steel ring 49, and a neoprene ring 50, pressed down by a spring engaging the inner race ring of the bearing 46. The socket 52 into which the flange 41 extends,

and which carries the seal, communicates at its upper end with the upper end 01' the processing chamber through a passage 54, so that the materials being processed cannot come in contact with either the rotary seal or the bearing. If g it will break along a fine line of cleavage when the rotation of the agitator begins.

The agitator, at its lower end, has a shaft extension 56, to which suitable driving means may be connected. The shaft extension may be mounted in a bearing 51, and between this bearing and the processing chamber there is provided a seal which will prevent the contact of any of the ingredients of the material being processed, with said bearing. This seal is disposed in a chamber 55 and is shown as including a pair of conical neoprene washers 56 pressed in opposite directions by a spring 66 into conical sockets in carbon rings 6|. Lubricant may be delivered under pressure to this chamber through a passage 52 in the head 31 and lubricant may be delivered under pressure to the bearing 51 through a nipple or oil cup 55.

The main ingredient, or main portion of a premix oi some-oi the ingredients, may be delivered through a passage 64 in the head 51 and enter the processing chamber at the bottom of the latter. After being processed the product may be delivered through an outlet 65 at the opposite end. It the material delivered through the inlet 54 be acidic or of other character which might adversely afiect the bearing 51 or the seal, another ingredient oi the desired mixture may be delivered through a supply passage 51 shown in dotted lines to an annular passage 66 formed around the shaft above the seal. This passage 56 may be disposed within and above a collar 65 projecting into a cavity in the end of. the shaft. The passage 55 is of substantially conical form, and its top portion is relatively restricted, so that it serves as a trap to prevent ingredients which might enter through the inlet 54, from contacting the seal or bearing. The center portion or I the passage is of substantially higher elevation than the periphery, so that the lip or flange 66 iorms an annular dam or wall.

If desired, some small quantity of the fluid delivered to the passage 66 from inlet 61 may continuously flow directly into the lowermost portion of the processing chamber countercurrent to any possible flow toward the seal from the processing chamber. As the trap is an inverted one, it will be seen that if the fluid delivered through passage 61 be of lighter speciflc gravity than that delivered through inlet 64, the heavier liquid cannot flow up over the annular ridge or dam 69 in the trap and get to theseal or bearing. During operation, sufllcient pressure is maintained on the fluid introduced through passage 66 to maintain a body of this fluid over the barrier or dam 69. On stopping the operation and draining the chamber, the main inlet will be opened, but during the draining the contents of the chamber cannot flow into contact with the seal because the passage within the collar 68 is maintained full of the lighter hydrocarbon liquid, by means of check valve in the feed line to passage 66, or other suitable means capable of preventing the liquid from flowing back out of that passage when the feed pressure is relieved.

The body of the agitator shaft has a plurality of passages 10 extending lengthwise thereof from the trap or chamber 66 and closely adjacent to the peripheral surface and communicating with the processing chamber through comparatively small ports 1| at their upper ends. These passages may be of various different lengths and arranged in any desired order so as to deliver fluid from the passage 51 to the processing chamber at points which are not only spaced lengthwise of the chamber but also circumferentially thereof so that the fluid delivered through passage 61 may be one of the ingredients being processed. In Fig. 9 there is shown an annular development of a section through the various passages Ill shown in Fig. 8. In this particular form it will be noted that the passages are eight in number and i divided into two groups so that the first and fifth are the longest, are diametrically opposite to each other, and deliver to the chamber at points farthest from the main inlet 84'. The second and sixth are somewhat shorter; the third and seventh are still shorter, while the fourth and eighth. which are also diametrically opposite to each other, terminate at only a short distance from the passage 66.

Thus, as the agitator is rotated at relatively high speed. the ingredient delivered through the passage 61 will enter the processing chamber at four different levels and at diametrically opposite sides of the main shaft at each of said levels. As the shaft is rotated, the liquid will be thrown by centrifugal force as jets into the other ingredients being agitated by the impact members 44 and being cooled by the jacket. This fluid may be delivered under pressure so as to form said jets. This is merely illustrative of one way in which an ingredient may be delivered to the chamber in quantities which are relatively small in respect to the main body of material in the chamber and at a plurality of spaced points, for mixing with or reacting with an ingredient or mixture of ingredients delivered through the inlet B4.

In this form of apparatus there is shown another means for delivering an ingredient to the processing chamber at spaced points along the length thereof and inwardly through the peripheral wall. This maybe incorporated in an apparatus which has or does not have the passages 10 and ports II above referred to., A plate is shown as welded to the outer surface of the wall 35 along the length thereof and extending through a slot in the outer wall 38 of the jacket for the temperature controlling medium. This plate and the wall 35 have passages 16 therethrough and the outer ends of these passages are connected to conduits 11 which may be connected to a source of supply for a fluid, or to different sources of supply for a plurality of fluids, to be delivered to the processing chamber along the length. or part of the length, thereof. The separate tubes Il may have individual va ves so that the fluid may be delivered at difierent rates in different port ons of the length of the chamber, or the ports 16 may be of different sizes.

Instead of providing a plate 15, there may be provided a plurality of collars or plugs through which the passages 18 extend. The plate 15, in effect, forms a partition in the jacket but this is immaterial, as the lower end of the plate preferably terminates above the header 40 so that the temperature changing medium may readily flow upwardly on opposite sides of the plate and there is no need for its circumferential flow.

In Fig. 7a is shown a conduit Ila disposed in and extending lengthwise of the temperature controlling jacket, and communicating with all of the ports 16. The same constuction shown in Figs. 7 or 7a maybe duplicated at the opposite side of the chamber if it is desired to introduce a further ingredient or separate portion of the same ingredients on opposite sides.

' l0 ber, and in order to obtain this result, it is necessary to vary the relative rates of flow of the ingredients. the flow or pressure of the temperature connections 80 at their outer ends for temperature recording instruments.

The apparatus may be employed for conducting processes at a temperature very substantially above or very substantially below atmospheric temperature, and in that case the Jacket 38 is encased in a thick layer of insulation 8|.

- As will be noted from Figsmi and 9, the passages 10 extend along only a comparatively short portion of the length of the agitator shaft so that all of the fluid introduced through the passage 68 will enter the processing chamber in the lower part thereof. The passages I6 may be distributed along the full length of the chamber, but as indicated in Fig. 4, the plate 15 terminates only shortly beyond the middle of the chamber so that all of the additional material delivered through tubes "or Ila will enter at spaced points along the lower half of the chamber. Thus, the upper half will serve for the further intermixing or emulsifying of ingredients already admitted to the chamber, or for holding the temperature for some time after a reaction has taken place or while it continues. is not necessary that'the thermo-couple wells extend along a greater section than do the inlets 16, as they are for indicating the temperature where reaction and/or main mixing may be taking place, so that proper control may be effected, but it will of course be evident that the thermocouple wells may extend along the full length to permit one to ascertain if further temperature change takes place beyond the upper port 16, or the thermo-couples may be entirely omitted, particularly if temperature change in the material is immaterial or does not take place.

From Fig. 5 it will be seen that the-inlets 16 It is important in some appartus to maintain an I from the plane in which the axis of the agitator is offset from the axis of the chamber. If the shaft be rotated clockwise, as viewed from the drive end, and as indicated in Fig. 5, the material in the chamber will be traveling at its highest speed at the left of the agitator, as viewed in Fig. 5, and the material delivered through the inlets I6 will be drawn directly into the part of the chamber where the velocity is the greatest and the layer of material against the peripheral wall is the thinnest. On the other hand, if the shaft of the agitator be rotated counterclock-' wise, the added ingredient will join the stream where a portion will be projected tangentially into the space where the turbulence is due in part to the centrifugal action of the beater elements on the material in the path thereof and the throwing of material out into the layer beyond the path of movement of said elements. In either case the fluid entering the inlets I6 and/ or II will be swept in a tangential direction by the high speed annular movement of the mass in the chamber. For some types of materials it may be found best to rotate the agitator counterclockwise, and

. for other types of materials it may be found best to rotate it clockwise or to place the inlets at Ordinarily it some other positions. The material delivered through inlets I8 may be under high pressure so as to form high velocity jets, aiding in the mixing action.

The construction shown in Figs. 10 and 11 is similar in many respects to that shown in Figs. 4 and 5 but differs in many details and particularly as to the position and arrangement of the inlets for the added ingredients and the character of the seals. The construction includes a processing chamber having a peripheral wall 83 surrounded-by a jacket 84 providing a space for the temperature controlling medium, and outside of this a layer of insulation 88. The bottom and

top walls

88 and 81 support the

shaft extensions

89 and 88 of the agitator shaft, which latter may be hollow with a peripheral wall 88 and end walls 9| and 92. The peripheral wall is provided with radially extending pins. 88 serving as impact or beater elements.

The main ingredient or ingredients may be delivered through an inlet 94 in the bottom wall and the product may pass out through an outlet 98 in the top wall. The added ingredient may be delivered through a pipe 98 extending lengthwise of the processing chamber and beyond the path of movement of the agitator and preferably adjacent to the peripheral wall 83. This may extend through the top wall and connect to a suitable source of supply and its lower end may be held in position by a closure plug 91 extending into a socket in the bottom wall. The pipe may have a series of very small apertures 98 arranged in a row lengthwise of the pipe and these apertures may be only in the lower section of the pipe or along the entire length ofthe pipe or only at the upper section, depending upon the particular process to be carried out and the ingredients employed. Although apertures 98 may face the agitator, they preferably face in a tangential direction so that the fluids delivered through said apertures will enter the turbulent stream and any heat of reaction between the fluids will be almost instantly removed as the turbulent stream is forced against the wall 83, which serves as a heat transfer wall if the jacket 84 be provided and if a cooling medium be delivered to it.

As previously noted, Fig. 11 is a section at right angles to the plane of Fig. 10 and shows that diametrically opposite to the inlet pipe 98 there may be provided a tube 99 mounted in the same way but having thermo-couples I88 along the length thereof so that the temperatureof the material at any point along the length of the processing chamber may be determined. The inlet pipe 98 and the'thermocouple'tube 99 are preferably arranged midway between the portion of the processing chamber of greatest radial dimension and the portion of minimum radial dimension.

The upper end wall 81 may have adetachable plate I8I which carries a bearing and seal and the lower end wall 88 may have'a somewhat similar plate I82 likewise carrying a seal and a shaft bearing. These may both be somewhat similar to that shown at the lower end of Fig. 4 and a detailed description thereof would seem to be unnecessary, other than as to certain details.

There may be provided a passage I88 through which mercury or other suitable sealing liquid may be delivered under pressure so as to form a further seal in an annular groove I84 above the main seal. Instead of delivering added ingredient to the chamber through longitudinally extending passages in the rotor, as shown in Fig. 9,

12 such added ingredient may be delivered through a passage I to an annular groove I88 above the groove I 84 to which mercury is supplied. The plate I82 is shown as provided with an annular flange I81 internally and externally tapered and spaced from the under surface of the lower end wall 8| of the a itator so as inform a seal and an annular passage I88 which may receive added ingredient from the annular groove I86; This annular passage I88 may be provided with radial passages I88 for discharging, into the processing chamber, added ingredient delivered through the passage I88. The outlets of the separate passages I88 may all be at the same distance from the end of the agitator or they may be at different angles so as to deliver at different elevations. The ends of these passages may be wholly or pargially closed by plugs to control the flow of the ets.

At the top the flange II8 around the seal and which extends into a cup III may have its surface roughened and the space between the opposed surfaces may be filled with parailln or wax or other material which may be poured in hot and set up to form a seal which will break but leave no appreciable clearance when rotation of the shaft starts. The material should be one insolu-v ble in or immiscible with the fluids being processed.

It will be obvious that various details of the construction may be varied through comparatively wide limits depending upon the character of the fluids to be processed, the temperature and pressure to be maintained, and various other factors.

Various new and important processes may be carried out in the various forms of the apparatus illustrated and certain of such processes are claimed in companion applications, but in the present application only the apparatus is being claimed.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A mixing apparatus having a substantially cylindrical elongated chamber having a peripheral wall presenting a substantially smooth inner surface, said chamber being provided with an inlet and an outlet for the continuous flow of a fluid generally lengthwise therethrough, a jacket encircling said chamber and having an inlet and an outlet for a heat exchange medium, and an agitator within said chamber and including a shaft of a diameter equal to substantially onehalf that of the chamber, and having its axis eccentrically positioned in said chamber to an amount not to exceed the radius of said shaft, and provided with beater elements spaced apart along the length thereof and offering relatively small resistance to said'through flow, whereby the circumferential flow of the fluid in said chamber is substantially greater at one side of said agitator than at the opposite side and stratification of said fluid adjacent to said jacket is prevented.

2. An apparatus for continuously processing flowable material, including an elongated chamber having a substantially cylindrical peripheral wall with a substantially smooth inner surface, the length of said chamber being at least as great as the diameter thereof, an inlet at one end and an outlet at the other end to permit the flow of a material generally lengthwise through said chamber, and an elongated agitator within said chamber and having a shaft and beater memthrough flow, the overall diameter of the agita tor being at least one-half the diameter of said chamber, the diameter of the shaft being at least one-half the overall diameter of the agitator, said shaft being disposed parallel to and eccentric with respect to the axis of the chamber, thus pro-' viding a region of maximum clearance between.

14 5. An apparatus for continuously processing ilowable'material, including an elongated chamber having a substantially cylindrical peripheral the shaft and the chamber wall at one side, and. v

a region of minimum clearance at the diametrically opposite side of said shaft, the extent of said eccentricity being such that said beater members are closely adjacent to said wall in the region of minimum clearance, and whereby the material being treated is forced at high velocity between said wall and said shaft in the region of minimum clearance and has a turbulent flow in the region of maximum clearance, a part of said flow being between the beater members on the"- shaft, and a part being between the path of movement of the beater members and said wall in the region of maximum clearance.

3; An apparatus for continuously processing flowable material, including anelongated chamber having a substantially cylindrical peripheral wall with a substantially smooth inner surface.

the length of said chamber being at least as great as the diameter thereof, an inlet at one end and an outlet at the other end to permit the flow of a. material generally len thwise through: said chamber, and an elongated agitator within said chamber and having a shaft and beater members secured to said shaft along the length thereof and around the periphery thereof, and spaced apart to offer relatively small resistance to said through flow, the overall diameter of the agitator being at least one-half the diameter of said chamber, the diameter of the shaft being at least one-half the overall diameter of the agitator. said shaft being disposed parallel to and eccentric with respect to the axis of the chamber, thus providing a region of maximum clearance between the shaft and the chamber wall at one side, and a region of minimum clearance at the diametrically opposite side of said shaft, the extent of said eccentricity being such that said beater members are closely adjacent to said wall in the region of minimum clearance, and extend approximately one-half of the distance to said wall in the region of maximum clearance.

4. An apparatus for continuously processing fl owable material, inc uding an elongated chamber having a substantially cylindrical peripheral wall with a substantially smooth inner surface, the length of said chamber being at least as great as the diameter thereof, an inlet at one end and an outlet at the other end to permit the flow of a material generally lengthwise through said chamber, and an elongated agitator within said chamber and having a shaft and beater members rigidly secured to said shaft, the overall diameter of the agitator being at least one-half the diameter of said chamber, the diameter of the shaft being at least one-half the overall diameter of the agitator, said shaft being eccentrically dis-'- posed with respect to the axis of the chamber, thus providing a region of maximum clearance between the shaft and the chamber wall at one side, and a region of minimum clearance at the diametrically opposite side of said shaft, the extent of said eccentricity being, such that said heater members come closely adjacent to said wall in the region of minimum clearance.

wall with a substantially smooth inner surface, the length of said chamber being at least as great as the diameter thereof, an inlet at one end and an outlet at the other end for the flow of fluid generally lengthwise through said chamber, and an elongated agitator eccentrically disposed within said chamber and having a shaft and beater members projecting therefrom along the length thereof and around the periphery thereof, extending substantially radially from the shaft, and

of a length substantially'less than the diameter s of'the shaft, the overall diameter of the agitator 7 being at least one-half the diameter of said chamber, to provide a region of maximum clearance between the shaft and the chamber wall at one side, progressively merging into a region of minimum clearance at the diametrically opposite side of said shaft.

6. An apparatus for continuously processing flowable materials, including a, vertically disposed substantially cylindrical chamber having top and bottom end walls: a rotatable agitator in said chamber with its axis eccentrically disposed in respect to the axis of said chamber, and having a shaft extending through said bottom wall, a bearing encircling said shaft outside of said chamber, said agitator having an annular recess in its lower end presenting an outwardly and downwardly inclined upper surface, and said bottom wall having an annular flange projecting into said recess, means for delivering one ingredient to the chamber at one side of said shaft, and means for delivering a second ingredient to said annular recess, whereby said bearing is protected from contact with said first mentioned ingredient.

'7. An apparatus for continuously processing ,ilowable materials, including a vertically disposed substantially cylindrical chamber having top and bottom end walls, a rotatable agitator in said chamber and having a shaft extending through said bottom wall, a bearing encircling said shaft outside of said chamber, said agitatorhaving an annular recess in its lower and presenting an outwardly and downwardly inclined upper surface, and said bottom wall having an annular flange projecting into said recess, means for delivering an acidic ingredient to the chamber at one side of said shaft, and means for delivering a lighter ingredient to said annular recess, whereby said bearing is protected from contact with the said first mentioned ingredient, and whereby rotation of said agitator tends to cause flow of material from said flange into said chamber by the action of centrifugal force.

-8. A mixing apparatus having a chamber provided with a substantially cylindrical peripheral wall, an inlet at one end of said chamber and an outlet at the opposite end, an agitator having its axis eccentrically positioned in respect to the axis of said chamber and having beater elements whereby the circumferential flow of the fluid in said chamber by the action of said heater elements is substantially greater at one side of said agitator than at the opposite side, and means for projecting a second fluid into said chambersaid shaft and disposed approximately midway between the minimum and maximum radii of the chamber in respect to the axisof the shaft, and having a plurality of openings along the length thereof and directed substantially tangentially of said agitator.

10. A mixing apparatus including a substantially cylindrical chamber, a rotatable agitator therein and having its axis eccentrically disposed in respect to the peripheral wall of said chamber, whereby circumferential flow in said chamber is at higher velocity at one side of the agitator than at the other, and means for delivering a fluid to said chamber at spaced points along the length thereof and in the direction of flow of the contents of said chamber around said agitator.

11. A mixing apparatus including a substantially cylindrical chamber having an inlet at one end and an outlet at the other, an agitator having a shaft eccentrically disposed in said chamber, a delivery pipe in said chamber substantially parallel to said shaft and disposed approximately midway between the minimum and maximum radii of the chamber in respect to the axis of the shaft, and having a plurality of openings along the lengthy thereof and delivering in the direction of rotation of saidagitator.

12. A mixing apparatus including a vertically disposed substantially cylindrical chamber, an} agitator therein and having a vertically disposed shaft, a bearing forthe lower end of said shaft, an inlet-for said chamber for one ingredient to be processed,'a trap at the lower end of said chamber encircling said shaft, and means for delivering a second ingredient to be processed to said trap, said agitator having a plurality of delivery passages .leading from said trap to said chamber.

13. A mixing apparatus including a vertically 16 spaced points in said chamber along the length thereof.

16. A mixing apparatus including a chamber having a rotatable agitator therein and provided with a shaft extending to the exterior of said chamber, a bearing for said shaft, a seal around said shaft and between said bearing and the interior of said chamber, a liquid trap above said seal, means for delivering liquid to said seal, and means for distributing liquid from said seal to spaced points in said chamber around the circumference of said agitator.

17. A mixing apparatus including a chamber having a rotatable agitator therein and provided with a vertically disposed shaft extending to the exterior of said chamber, a bearing for the lower end of said shaft, a seal around said shaft and between said bearing and the interior. of said chamber. a liquid trap above said seal and having an inlet and an outlet, and means for delivering liquid to said seal, said trap encircling said shaft and having an annular upwardly extending wall terminating above the inlet and the outlet from said trap.

disposed substantially cylindrical chamber, an

agitator therein and having a vertically disposed shaft eccentrically disposed in respect to the peripheral wall of said chamber, a bearing for the lower end of said shaft, an inlet to said chamber for one ingredient to be processed, a trap at the lower end of said chamber encircling said shaft, means for delivering a second ingredient to be processed to said trap and thence to said chamber to thereby prevent passage of said first mentioned ingredient to said bearing, and means for delivering a fluid to said chamber at spaced points along the length thereof and in a direction substantially tangential to said agitator.

14. A mixing apparatus including a chamber having a rotatable agitator therein and provided with a shaft extending to the exterior of said chamber, a bearing for said shaft, a seal around said shaft and between said bearing and the interior of said chamber, a liquid trap above said seal, means for delivering liquid to said seal, and means for distributing liquid from said seal to spaced points in said chamber.

15. A mixing apparatus including a chamber having a rotatable agitator therein and provided with a shaft extending to the exterior of said chamber, a bearing for said shaft, a seal around said shaft and between said bearing and the in-' terior of said chamber, a liquid trap above said 18. A mixing apparatus including a chamber having a vertically disposed rotatable agitator shaft extending to the exterior of said chamber, a bearing for the upper end of said shaft, a seal below said bearing and a trap around said shaft and below said seal, said trap comprising a cupshaped recess for retaining liquid and communicating with the interior of said chamber only above said seal.

19. A mixing apparatus including a chamber having a rotatable agitator therein and provided with a shaft extending to the exterior of said chamber, a bearing for the upper end of said shaft, a seal below said bearing and a trap around said shaft, below said seal and communicating.

with the interior of said chamber only above said seal, said trap containing a fiowable material preventing the material being processed from contacting with said seal.-

BRUCE DE HAVEN MILLER.

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

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