US 1792067 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
Fefb. W', WEE. G. A. BROWN.
DEVICE FOR PRODUCING DISPERSIONS Filed April 16, 1926 3 Sheets-Sheet l WWW/37mg@ Feb. 1Q, gl. G` A, BRQWN DEVICE FOR PRODUCING DISPERSIONS Filed April 16 1926 3 Sheets-Sheet 2 DEVICE FOR PRODUGING DISPERSIONS Filed April 16. 1926 C5 Sheets-Sheet 5 -er I GEORGE ARTHUR BROWN, OF SALEM, MSSACHUSETTS, ASSIGNOB T0 BENNETT, IN'- CORPORATED, 0F SALEM, MASSACHUSETTS, A CORPORATION 0F MASSACHUSETTS fFOE PBODUCIN G DISPERSIONS -Application. filed April 16,
rll`his invention has relation toa methodof and device 'for producing dispersions, and more particularly dispersione of thermoplastic materials such as bitumens, gums and waxes, and has 'for its object to provide a method and a device for producing such dispersions in a continuous, eilicient and economical manner.
le the method and device of the present invention is to be described in connection with the production of dispersions of thermoplastic material, it should be understood that the method and device may be employed, for other analogous applications.
ln producing dispersions of thermoplastic materials, such, for example, as are set forth in patent application Serial N o. 55,063, filed September 8, 1925, by Albert L. Clapp, the process employed comprises heating and melting the material to be dispersed, and while in molten condition intimately mixing and agitating with it a heated solution of a dispersing agent, e. g., a solution of sodium silicate. rllie mixture is agitated for a relatively, short period of time, so that substantial saponication (when the material to be dispersed is saponiiable) is not effected.
- To preclude such material saponification, as
well as to'prevent a coalescence of the dis-- persed particles into larger agglomerates `while they are molten, the dispersion is preferably rapidly cooled'immediately after it is produced to edect a congelation of the dispersed particles. f j
In accordance with the method of the present invention, one of the constitutents of the dispersion, preferably thedispersing solustream and, while it is being agitated, the inaterial to be 'dispersed is introduced and agie tated .thereinto in a continuous stream fed at a predetermined constant rate.
Broadly stated, the device for carryingout this method comprises a shell provided with agitating blades through which materials may be continuously passed, means for I-feeding-the materials in continuous streamsv at' predetermined constant rates into the shell, and means for regulating the relative rates of feed of such materials.
192e. semi no. 102,552.
With these and other objects in view, the
invention consists -in certain novel features the devieein combination with certain auxiliary apparatus.
Figure 2 represents a side view of the device.
Figure 3 represents in isometric view, cups for feeding the materials in predetermined, constant amount into the shell.
Figure 4 represents a section on the line L.1l-T4 of Figure l.
Eigures 5, 6 and 7 represent sections taken respectively on the lines 5 5, 6 6 and 7 7 of Figure 4.
Figure 8 illustrates a side view, partly in section, of a preferred form of feed cup provided with meansfor regulating the rate of feed of material.
Figure 9 represents -a plan view of the same. f
AFigures 10, 1l and 12 illustrate certain de; tails thereof. Y
Referring to Figure l of the drawings, 2 represents a tank inwhich a supply of a thermoplastic material to be dispersed, e. g., a mixture of paraflin and rosin, is maintained in heated, liquefied state.' The material be heated and liquefied in the tank 2 by suitable' heating means, as by steampoils. Or, if desired, the material may be melted in a suitimilarly, a supply of t e dispersing ur-solution-is maintained in a tank- 1., The tanks 1 and 2 are preferably respectively provided with'screening partitions 13 and 113, so as to retain impurities contained the raw ma-V the material is continuously withdrawn from the tank 2 by a pump 7, forced through the may f able melter, and then su plied to the tank. tion, .is fed and agitated in a continuous S n pipe 8, and discharged into a feed control curi thus maintaining a substantially constant level or head in the cup and ensuring a fiuidity of the material contained therein. The bottom of the cup 9 comprises a discharge orifice of predetermined diameter, so that the material may be continuously fed at a predetermined constant rate by gravity into the intake end ofthe shell through a dis-V charge pipe 12.
The dispersing solution is similarly fed into the intake end of the dispersing device. L
For this purpose, a pump 3 communlcates .with the tank 1, forcing the solution through a pipe 4 into a feed cup 5 arranged above t e intake end of the shell. The dispersing solution is maintained at a constant level or head in its cup, by an overflow pipe 10, which returns the excess solution into the tank 1. The dispersing solution Hows by gravity at predetermined, constant rate through an orifice of predetermined diameter formed through the bottom of the cup, thence into ay pipe 6 which discharges the solution into the intake end of the shell.
1n Figures 8 to 12 there is shown a preferred form of feed cup 70, which may be employed for either or both the dispersing solution and the material to be dispersed, preferably the latter at least.
The cup is provided with inner and outer side walls 71 and 72, respectively, forming an annular jacket 73 about the cup, through which a suitable heating medium such as steam may be passed to aid in maintaining the material in the cup at the proper temperature for dispersion. The steam inlet and outlet pipes are respectively shown at 74 and 75, and the material inlet and overflow pipes are respectively designated as 76 and 77. i
Provision is also made to vary readily andaccurately the rate of discharge of material from the cup, so that the relative proportions of dispersing solution and material to be dispersed may be adjusted as desired. This is very desirable, inasmuch as the different thermoplastic materials require vary;
ing quantities of despersing solution to effect a dispersion of the desired character. As shown, a tube 78 extends vertically and centrally through the cup, being pressed into or otherwise fixed in the bottom 79 and the top 98 thereof projecting beyond the wall of the cup. .Rotatable within the tube 78 and closely iitted therein at its upper and lower portions but of smaller diameter at its central portion to avoid excessive friction in rota-` tion, is a tube 7 9a, provided with an orie magos? 80, registerable to a greater lor lessendegree with a corresponding orifice 81 in the tube 78 by rotation of the tube 7 9a, within the tube 78. As shown, rotation is effected by manipulation Jof a lever or adjusting handle 81a,
oted to the portion 83 against the upper surface of the rim and also clamping the arm imposition. The finger is urged against the screw., so thatpwhen the set screw is turned up the arm may be freely turned, this action being aorded as by a tension spring 86 fixed at its upper end to the outer end of the finger and at its lower end toa pin 87 on the portion 83. A scale 88 calibrated preferably in terms of rate of discharge of material through the orifice, may be provided on the cup positioned in reading relation to the portion 83a of the arm, so that the arm may be readily set to give the desired rate of discharge through the orifice. The inner tube,`togethe'r with this arm, maybe withdrawn from and assembled with the cup as a. unit, by notching the rim as at 89 to allow the portion 83a, to be passed therethrough. The cup as a whole may be supported by a bracket 90 fixed to a pipe 91 discharging into the shell 20, .the matelal flowing from the cup through the orice of the inner pipe, which extends and discharges into the pipe'. l v
rlhe shell 20, as shown, is inclined to the horizontal. Within the shell there is axially mounted for 'rotation/a propelling and agitating member, designated as a whole as 2.1. The member comprises a shaft 22 which 1s journaled at its lower end' in a bearing 23 having the radial arms 24, by which it is secured to the shell 20, as by bolts 25. The
shaft 22'is journaled at its upper end in a bearing 27 which vfits within and is' held in position by a'cap 28 screwed to the upper endV Y t of the shell. The shaft is provided with agitating and propelling blades 30, spaced yangularly about the shaft, which are supported and fixed as by welding at spacedv intervals along the shaft, by means of a series of spiders 31 suitably fixed thereto and defining sections or zones in the shell. The blades 30 are helicoidal in configuration and are spaced from the shaft, thus imparting a whirling or agitating in addition to' a propellin motion tol the materials fed into the device. referably,
the helicoidal configuration of the blades at the upper portion ofl the shaft 22' is steeper than at its lower portion, thus causing a more rapid agitation ofthe materials at the zone or section of the device where the materials come together and where tliel dispersion is troduce into the shell at the point where the to be produced. As shown, a quarter-turn ofthe blades is 'made at the upper shorter section or zone a between the spiders 31 and 31a, whereas only a quarter-turn of the blades is made between the spiders ofthe longer, lower sections or zones b, where suicient agitation for the prevention of agglomeration in addition to propulsion is desired.
The shaft 22 isrotated by a driving shaft 33 fixed thereto as by means of a flexible coui. Yplingr34: The shaft 33 may bedriven by any suitable driving means, a motor 36 supported by the device through a bracket 37 bein shown. The motor shaft 36a may be geared down to drivthe propeller shaft 22 at the desired rate of speed, through a worm (not shown) provided at its outer end, meshing with a worm gear at. the outer end ofthe shaft 33. e i
` The dispersing solution is discharged from the feed control cup 5 into the device into the zone a. immediately below the uppermost spider 31, and a rapid whirling or agitating motion is immediately imparted to the material. To secure optimum results in the production'of the dispersion, I have found that the material to be dispersed is preferably intermingled with the dispersing solution while the latter is in rapid agitation. Consequently the material to be dispersed is introduced into the device above thev zone in which the dispersion solution is introduced. As shown, the material to be dispersed is discharged int-o the shell above the uppermost spider 31. The material flowing downwardly into the rapidly agitated dispersing solution, is then rapidly agitated and mixed therewith, resulting in a dispersion. In actual operation, while the dispersion is being formed and agitated in the section or zone a, there is an apparent complete wall or partition formed by the Liotation of the spider 31 which separates the uppermost zone ofthe shell into which thel material to be dispersed is introduced and the zone a. immediately therebelow, into which the dispersing solution is fed,-the material penet-ating through. the apparent wall into the section a and being rapidly whirled together with the dispersing solution.
Under certain conditions, however, the procedure mayjbe reversed and the dispersing solution may be introduced into the shell above the uppermost spider 31 and the thermoplastic material to be dispersed may be introduced into and agitated in the zone a therebelow. This method entails certain disadvantages as it tends to fprevent the production o; a unif`1m dispersion or to cause a freezing or congelation of the thermoplastic material without eliecting a dispersion. In other words a localized action rather than the uniform dispersive elect obtained by the frst-mentioned procedure is promoted.
I have found it sometimes desirable to infsdispersion is 'being produced, a certain amount of steam, and have therefore pro-l vided a pipe' 38extending into the pipe 6, through which steam may be passed, along with the molten thermoplastic material, thus helping tounaintain it in fluid condition. A
vent opening 50 is also provided in the ppermost .'zone ofthe shell, to maintain suitable ressure conditions within the device. The ownward inclination of the shell 20, Valong with the feeding effort afforded by the blades 21, forces the dispersion out through the shell, from which it may be received into a barrel or other suitable container.
To preclude a material saponification when saponlfiable thermoplastic material is employed and also to prevent the coalescence of the discrete particles of the dispersion while molten, provision is made rapidlyr to cool the dispersion immediatelyl after it is pro.- duced. To this end. acooling jacket 51 4 is `formed about the shell 20, as by arranging i a cylindrical shell 40, of a larger diameter, thereabout, the annulus formed between the shells being sealed at its upper and lower ends by suitable sealing rings 41. Water may be continuously circulated throughthe cooling jacket in countercu'rrent fiow to the movenient of the dispersion. The water is introduced in regulated amount through a pipe 43, flows upwardly through the jacket and thence out through the discharge pipe 44. IThe discharge end of the device is thus maintained at the lowest temperature by the water. the temperature of the water rising toward the intake end of the device as the heat of the dispersion i's abstracted and absorbedV thereby, approaching thetemperature of the dispersion at the section or zone a and thus aiding in maintaining the materials at the desired temperature for eiective dispersion. By this means, the dispersed particles are caught or congealed in line condition imme- `ran d at an angle to the horizontal, to aid in t e propulsion of the material from the device. I have found that, under ordinary conditions of operation, an angle of about45 degrees to the horizontal permits proper rate of discharge ofvthe di rsion, provision being made to adjust this angle according to changes of conditions. For adjusting the angle, the lower portion of the shell 40 is provided with a lug 47, which is pivotally supported as at 48 by a column 49, and the upper portion of the shell 20 is provided at either side with a trunnion 60 journaledl in a yoke 6l, which is telescopically secured within a supporting column 62.
While l have described thedevice of this invention as being particularly applicable for the production of dispersions, it should be understood that this use is illustrative only, and that the device may be used for analogous purposes, or for any other uses for which it is found suitable.
Having thus described an embodiment of this invention, it should be obvious that various changes and modifications may be made therein without departing from its spirit or scope as dened by the appended claims.
l. A. device for continuously producing a dispersion of thermoplastic material comprising an inclined cylindrical shell, means for introducinga dispersing agent in a continuous stream at a predetermined-constant rate into the upper end of said shell, means for agitating the continuous stream of agent introduced into said shell, and means for feeding molten thermoplastic material by gravity in a continuous stream at predetermined constant rate into said shell above the point of introduction of said dispersing agent, said means comprising a tank for maintaining a supply of the material, a feed cup arranged above and discharging into the upper end of said shellymeans for constantly feeding an excess of molten material from said tank into said` cup, and an overow pipe communicating with the interior of said cup and returning the excess molten material into said tank.
2. A device for continuously producing a dispersion/*of thermoplastic material comprising an inclined cylindrical shell, means for introducing a dispersing agent in a continuous stream at a predetermined constant rate into the upper end of said shell, means for agitating the continuous stream of a ent introduced into said shell, means for ceding molten thermoplastic material by gravity in a continuous stream at predetermined constant v rate into said shell above the point of introduction of said dispersing agent, said means comprising a tank for maintaining a supply of the material, a feed cup arranged above and discharging into the upper end of said shell, means for constantly feeding an excess bf molten material from said tank into said cup, and an overflow pipe communicating with the interior of said cup and returning the excess molten material into said tank a pipe for introducing steam into the upper end ofsaid shell to maintain the material in molten condition, said shell having avent at its` upper end above the point of introduction of said molten material.
3.Vr A device ofthe class described, compris- Ving an inclined cylindrical shell, a shaft ared by said shaft and spaced angularly about and from said shaft for mixing and conveying materials introduced into said shell, and means located'at the upper end of said shell for driving said shaft.
5. A device of the class described, comprising an inclined cylindrical shell, a lshaft arranged axially Within said shell, helicoidal blades supported by said shaft and spaced angularly about and from said shaft for mixing and conveying materials introduced into said shell, means for driving said shaft, and a jacket arranged about said shell.
I6. A device of the class described, comprising an inclined cylindrical shell, a shaft arranged axially within said shell, helicoidal blades supported by said shaft and spaced angularly about .and from said shaft for mixing and conveying materials introduced into said shell, means for driving said shaft, a cylindrical shell of larger diameter arranged about'said first-mentioned shell, the annulus formed between the shells being 'closed at its upper and lower ends, and pipes communicating with said jacket for the circulation of a rent flow to the movement of the material in the shell.
'Z'. A device of the class described, .comprising an inclined cylindrical shell, a shaft arranged axially Within said shell, heloidal blades spaced angularly about and from said shaft for mixing and conveying materials introduced into said shell, a series of spaced spiders to which said blades are secured fixed to said shaft; and *means for driving said shaft.
8. A device of the class described, comprising an inclined cylindrical shell, a shaft arranged axially within said shell, helicoidal blades spaced angularly about and from said shaft for mixing and conveying materials introduced into said-shell; a series of spaced spiders to which said blades are secured fixed to said shaft and defining sections in said Shell, means for driving said shaft, means for introducing a stream of material in predetermined constant quantity into the section below the .l
uppermost spider, and means for introducing a stream of materlal 1n predetermined constant quantity into the shell immediately above said uppermost spider.
9. A device of the class demrihed, comprismedium through said jacket in counter-curing an inclined cylindrical shell, a shaft arranged axially Within said shell, helicoidal V.blades spaced angularly about and from said shaft for mixing and conveying materials introduced into said shell, a series of spaced spiders to which lsaid blades are secured fixed to said shaft, means for driving said shaft, cups for maintaining supplies of material to be introduced into and mixed within said shell arranged above said shell and discharging by gravity streams of material thereinto in predetermined constant rates,
v means for continuously supplying said cups with material, and overiow pipes communieating With said cups for maintaining a constant level of material therein.
10. A device of the class described, comprising an inclined cylindrical shell, a shaft arranged axially Within said shell helicoidal blades spaced angularly about and from said shaft for mixing and conveying materials introduced into said shell, a series of spaced spiders to which said blades are secured fixed to said shaft and defining sections in said shell, the curvature of said blades at one section of the shell into which certain of said materials are introduced being steeper than in the other sections, means for introducing 0ther material at a predetermined constant rate into said shell above said one section, and
means for drivin the said shaft.
In testimony W ereof I have aiixed my signature.
. GEORGE ARTHUR BROWN.