US1885283A - Colloid mill - Google Patents

Description

Nov. 1, 1932. w. OSTERMANN COLLOID MILL Filed May 6, 1924 collor Patented Nov. 1, 1932 outrun STATES-PATENT OFFICE wanna os'rnmrm, or oscnnnsnnnnn, enmrm, assranon, in: men assron- 4 mnurs, TO mvrs rnocnss conronarron, or

EATION OF DELAWARE JERSEY CITY, JERSEY, A com- COLLOID MILI- Application filed Kay 8, 1924, Serial No. 711.890, and in Germany Kay 18, 1828.

My invention refers to the comminution of solid substances by mechanical means and relates to a high speed mill of the so-called colloid t e whereinthe material, to be treated is su jected while'in a liquid vehicle to an intense disintegrating action for the purpose of securing fine comminution, dis persion, homogenization, or the-like.

\ Powders of colloidal fineness have hitherto been obtained as a rule by chemical treatment. It has already been tried to reduce solid substances to colloidal fineness by niechaninal means, but these means as hitherto used have not resulted in an economical and perfect reduction of ,the size of the particles, such as re uired.- Mechanical comminution is efiected by aid of several kinds of mills, more especially centrifugal mills and disintegrators. The substances to be comminuted to colloidal fineness are ground in such a mill for several hours in the resence of electrolytes, which are designe to act as dispersing means, and, in certain cases, also of protective colloids. It has, however, been found that these mills have only a low efiiciency, a very long time being consumed in grinding and moreover these mills require a very large consumption of power which is out of proportion to the quantity of substances comminuted per unit of time. Moreover, the suspensions thus obtained contain only a very small percentage of colloids, as'a rule not above 1%, much of the disintegrated substance remaining in a more or less coarse state.

The further treatment of this mass is also unsatisfactory, the liquid discharging from the mill being caused to pass throu h a centrifugal apparatus of complicate 'desi se for .efiecting the se aration of t e from the coarser artlcles. The particles suspended in the liquid must then be reduced to the state required in each case by dr 7 g.

%i ese difiiculties are obviated according to the present invention by first-mechanically comminuting the substances, which-have been suspended in a suitable li 1nd, in a mill, such as that hereinafter described, without adding any dispersing agents or protective colloids, until they have been reduced to w. lo dal fineness. The liquid having the colloldal substances suspended therein is then supplied by means of an atomizer directly into a drying apparatus of some well known kind in which the colloidal substances are at once converted into a dry powder.

In the drawing aflixed to this specification and forming art thereof a device embodymg my invention is illustrated: diagrammatically by way of example. In the drawing Fig. 1 is an axial section ofthe mill of my invention, while Fig. 2 is a cross section drawn to a larger scale, showing the alternate teeth and channels provided in the rotor and'casing of the, mill 3 is a vertical cross section showing the mill, atomizer and drying apparatus.

Referrmg to the drawing, A is a rotor made of high grade steel and provided with straight-lined or helical channels a (Fig. 2) of curved or angular cross section. B'is the stationary casing or so-called stator surrounding the rotor and which has similar channels and teeth and is cooled by water Jr the like. The rotor and stator can be conical,

as shown in the drawing, or cylindrical in teeth edges, of a shearing action upon the film by cooperating teeth surfaces, and of a churning action upon the liquid in cooperating channels. The tube C supplies the liquid ccntainin the suspended material into the chamber il in tangential direction. That portionof the chamber which adjoins the rotor has the shape of a funnel. On the rotor shaft F a helical feeding member M is mounted which forces the material fed into the Y ates with the ba and B of the mill. The materi part of the material might evade product is produced chamber to enter the space confined between the rotor and the stator cas' The comminuted material escapes at e other end of the rotor, another helical blade N bein mounted at this end, which serves for fee ing the comminuted material into a tubular colloidal solution against an inclined baffle plate I mounted in the upper part of the rying chamber H. The compressed air nozzle K acts in two ways: It serves for atomizing the colloidal sus ension escaping from the socket 0 the combination of parts thus acting as an injector, whereby the mill itself is ,partly relieved and the consumption of power is reduced. On the other hand, the

atomization eiiected by the jet of'hot compressed air esca ing from nozzle K coo ered plate I in further reduc ing the size of the particles of the substance suspended in the liquid, and the finely atomize liquid entering the d 'ng chamber is acted upon by heat or the hke, whereby the substances suspended therein are reduced to a dry powder of colloidal fineness. This combination of fine disintegration with subsequent atomization and drying is the subject of my issued Patent No 1,718,184.

The particular manner of operation of the mill which is the subject of the present invention is a continuous one. No clearances are formed, such as exist in other mills, whereby the disintegrating action of the cooperatingl members A tegrated is continually kept in motion and dead corners and anglles are avoided. The helical feeding blade forces all the material to enter the mill. The injector-like efiect produced by the nozzles O and K produces a reduced pressure or suction eifect 1n the disintegrating chamber which'also assists the circulation of the material. By the instantaneous atomization and d of the material after it has. been groun the finished in the quickest way without any dispe colloids being inasmuch version of the li uid suspension into a' dry powder is efi direct y and instantaneously. In consequence thereof, no centri as the con fuging apparatus is required and the grinding rocessiscarriedthroughinashorttime. y concentrated suspensions can be acted upon in this mill, the concentration merely depending upon the ofpassage of the males. 7

to'be disin-- erating relatlonshi agents and protective fofthe teeth, to a film I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

1. An apparatus for homogenizing or emulsifying materials comprising mem ers' relatively movable at a high speed having cooperating faces between which the materials are fed for treatment, the faces of both members being provided with alternating channels and teeth arranged in a direction generally transverse to the movement of one of said members, the teeth of both members having fiat faces spaced with a slight clearance therebetween, and the channels of both members being carried in cross-section and relatively disposed so that when the members are relatively moved at a high speed the materials fed between the members are subjected to the film beating action of passing teeth edges, to the film shearing'action of cooperating'teeth surfaces, and to the repercussive churning action of cooperating channels.

2. An apparatus for homogenizing or emulsifying materials comprising a pair of mem bers having closely adjacent, non-contacting, cooperating faces relatively movable one past the other at a high speed etween which the materials are fed for treatment,each of said' faces being provided with alternating continuous channels and continuous teeth arranged in a direction generally transverse to the movement-of one of said faces, said teeth having flat surfaces and said channels being curved in cross-section so that when the faces are relatively moved at a high speed, the materials fed between the faces are subjected to the film beating action of passing teeth sides and edges, to the film shearing action of cooperating teeth surfaces, and to thechurning action of cooperating channels.

3. An apparatus for homogenizing or dispersing materials having a frusto-conical rotor surface rotatable at a high speed and having alternate which comprises a member teeth and channels arrangedin a direction generally transverse to the movement of said surface, and a member having a frusto-conical stator surface surrounding said rotor surface in closely adjacent, non-contacting, cooptherewith and having alternate teeth and c annels arranged rection generally transverse to the movement of said rotor surface, the teeth on both surfaces terminating m respectively op flat faces which form 'edges'with the sides of their respective teeth, an ing their sides sloping inwardly towards the channel bottom, whereby materials fed between the surfaces relatively moving at a bi are sub'ected to a film shearin ac i dn tween the 1 g coo ratingterminalfaces bzatingaction by 439 said channels havbers for centrifugally impellin ing teeth sides and edges and to a' churning action by cooperatin channels.

.4. An apparatus or the comminution of materials in a liquid medium which comprises a pair of members having closely adjacent,

non-contacting, concentric surfaces of revolution relatively movable at high velocity between which the liquid containing the materials to'be comminuted is fed for treatment, and a rotatable helical vane disposed axially of said members and surrounded by but substantially spaced from the outer of said memthe liquid material outwardly and forwar ly and into the narrow gap between said surface.

5. An apparatus for the comminution of materials in a liquid medium which comprises a cylindrical rotor surface rotatable at high velocity, a casing member having a cylindrical stator surface surrounding said rotor surface in closely adjacent, non-contacting coaxial relationship therewith, a rotatable helical vane mounted axially of said rotor at one end thereof and substantially spaced from said casing for centrifugally impelling the liquid material outwardly and forwardly and into the gap between said surfaces, and a rotatable helical vane mounted axially on said rotor at the opposite end thereof and substantially spaced from said casing for centrif ugally expelling the liquid material discharger from said 'ga 6. An apparatus or the comminution of materials in a liquid'medium which comprises a rotor member rotatable. at high velocity, a casing member surrounding said rotor memberin closely adjacent, non-contactin relationship therewith, said casing and sai rotor member generally defining a narrow workin gap in which the liquid material is subjecte' to a comminuti'ng action, said casing being contoured to gradually converge towards said rotor in the manner of a funnel from the end of said rotor to a point on said rotor at a distance from the end thereof whereby said gap is widest at its mouth, and a rotatable helical vane mounted axially of said rotor and substantially spaced from said casing for centrifugally impelling the liquid material out wardly and forwardly towards the inlet end of saidgap.

In testimony whereof I afiix my si ature.

WALTER OSTER NN.

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