US2738931A

US2738931A - Comminuting apparatus and method

Info

Publication number: US2738931A
Application number: US229911A
Authority: US
Inventors: Schneider Ernst Walter
Original assignee: EQUIP IND ET LAITIERS SOC D
Current assignee: D'EQUIPEMENTS INDUSTRIELS ET LAITIERS Ste; EQUIP IND ET LAITIERS SOC D
Priority date: 1949-10-31
Filing date: 1951-06-05
Publication date: 1956-03-20
Anticipated expiration: 1973-03-20

Description

March 20, 1956 E. w. SCHNEIDER 2,733,931

COMMINUTING APPARATUS AND METHOD Filed June 5; 1951 2 Sheets-Sheet l March 20, 1956 E. w. SCHNEIDER COMMINUTING APPARATUS AND METHOD 2 Sheets-Sheet 2 Filed June 5, 1951 FIG.3

.l'nvemon- ERNST w. SCHNEIDER United States Patent coMMmurrNG APPARATUS AND ivmrnon Application June 5, 1951, Serial No. menu in Germany October 31, 1949 Public Law 619, August 23, 1954 Patent expires October 31, 1969 10 Claims. (Cl. 241-462) This invention relates to a method and apparatus for finely subdividing materials forv producing finely subdivided stable and intimate mixtures, such as emulsions, suspensions or dispersions.

For this purpose there are already known many methods and machines which operate on the material to be treated by applying external forces thereto. By these methods subdivision into particles of colloidal size is attained only by excessive expenditure of energy or by an extended time of treatment of the material.

Furthermore it is known to produce finely subdivided intimate mixtures in fluid phase by ultrasonic means. According to the prevalent theory the subdividing is principally caused by the external influence on the outer zones of the material under treatment of the sound energy causing cavitation efiects in these zones. However the cavitation not only effects the desired subdivision of the material to be treated but also tends to deteriorate the surfaces of the container walls. Therefore ultrasonic installations have but a short life. Furthermore there is always the danger that the subdivided product will be contaminated by traces of foreign material. 'Ultrasonic treatment is also disadvantageous with regard to the high sound energy and the long time of treatment needed.

The primary object of this invention is the provision of an improved apparatus and method of mechanically subdividing materials by forces acting directly upon the single or individual particles thereof.

A further object of the invention consists in imposing the subdividing forces in such a manner that the material will readily disintegrate by operation of resonance effects.

According to a feature of the invention, the material to be subdivided is subjected to internal forces such as cavitation and/ or underpressure implosion by moving it through a system consisting of narrow spaces or gaps and roomy spaces or exciter chambersregularly alternating with each other.

The method of subdividing material according to the invention is differentiated from the prior art cited above in that the forces do not act externally and therefore indirectly but internally and throughout thebody of the material under treatment. According to my present theory these disintegrating forces are believed to be cavitation or underpressure implosion respectively. However, these cavitational effects are produced not only indirectly such as by a sound generator in the outer zones of the material but directly and mechanically in the verycore of the material. Therefore subdividing and mixing occur very efiicaciously and in the shortest time, the material not being contaminated by particles of the container or of other parts of. the installation. Another advantage of the improved method consists in that the subdividing internal forces are not bound to the use of ultrasonic frequencies but can also act'at substantially lower frequencies. Thus even material difficult to disintegrate can be changed into finely divided, stable and intimate mixtures by internal forces generated in small vessels and V with small energy input;

In apparatus according to the invention chambers of hemispheric or hemicylindrical form have been found to generate exceptionally strong internal subdividing forces.

Theterm moving the material through an area consistingof alternating narrow spaces and roomy spaces is intended to comprise all kinds of relative movement between the materialand the system of gaps and exciter chambers. Therefore the invention canbe performed by moving the mass through an 'existingsystem of alternating gaps and exciter chambers or by generating the alternating of gaps and exciter chambers with regard, to the single mass particles during operation.

Another feature of the invention consists in adjusting the frequency of the passage of the exciter chambers or the speed of passage of the material through the gap spaceto the qualities of the material in such a way that the material is disturbed in its textural strength and especially brought into resonance. In this sense materials of high internal strength such as metals or highly polymeric substances are treated under conditions of frequency of the ultrasonic range. However the term ultrasonic frequency does not at all mean that ultrasonic energy, namely vibration, is generated. It only says that the forces generated in the interior of the material are changing with a frequency having the numerical range of ultrasonic vibrations.

The invention will now be described in detail with reference to the accompanying drawings which illustrate a preferred exemplary embodiment of a comminuting apparatus according to the invention. In the accompanying drawings: 7

Fig. 1 is a view in side elevation, partly in section, of a comminuting apparatus according to the invention;

Fig. 2 isa sectional view at an enlargedscale of apparatus of Fig. 1; I

Fig. 3 is a fragmentary plane sectional view taken on the line 33 of Fig. 2; and

Fig. 4 is a fragmentary plane. sectional view taken on Cthe line 4-4 of Fig. 2. 1 1 I The minutely dispersing machine according to Figure 1 comprises adriving motor supported in upright position inside a pedestal or motor housing M, and the dispersion or comminuting machine proper, generally indicated at D. The speed of the motor may be adjusted by any ap-' propriate means such as the rheostat 3, The casing G of the comminuting machine is fixed on the motor flange in the usual way, for instance by means of. screw bolts. The rotor 1 of the dispersion device is coupled to'the shaft'of the motor M. In the casing G of the dispersion device an insert 2 is provided, which acts as the carrier of the stationary part of the dispersing system or systems. On the upper side of the dispersion machine is the hopper 4 for the material to be treated and at-the periphery of the casing G is the outletbranch S for the finished prodnot. In the constructional form according to Figure l the rotor 1 rotates within the stationary part 2 of the dispersion system.

Referring particularly to Fig. 2, the operating parts of the comminuting or dispersing machine are seen to I include the relatively rotatable members 1 and 2, 1 being Radially outside the space between the conical face 8 and the plane face 7 both-members are provided with an annular surfacemonforming to aacommon surface of revolution. These annular surfaces,9 on ,theirotorand 10 onthe statonrarein the embodiment illustrated plane surfaces. The members ,1 andi2- are supported, by-means of :the casing-G in Fig. 1 and the bearings (not shown) which support the rotor 1 ,withrespect to the casing, so that. the members 1 and 2 rotate relatively to eachother with close clearance .at-the surfaces 9 and 10.

l-Radially inside the .annular portions 9 and 10, which formian outer limit' to the .conical space :between members 1 and 2, :there are provided on members 1 and 2 a plurality of ring-shaped arrays of .teeth or projections concentn'ein theimachine axis. In Fig. 2 arrays of

teeth

11, 27 and 13 project fromthe rotor and arrays of teeth -12 and :14 project from the stator, the .rotor arrays alternating in radial position with those of the stator, the:.teeth.of.=eacl1arrayprojecting from the member on which they are mounted to pass with close clearance the face 7 or .8 as :thecasemaybecof the other member.

Radially outside the annular portions 9 and 10 the members are shaped, by the provision of an annular depression in at least one member, as at 16 instator 2, to define an annular cavity between the two members. Each of the members 1 and 2 is provided within the annular cavity so defined with a multiplicity of teeth, 17 on the rotor and 18 on the stator, whichproject into cavity 16 and which present thereto faces indicated at 17' and 18 respectively in Fig. 3.

Teeth

17 and 18 move past each other with close clearance at edges or faces thereof, identified at reference characters 17" and 18" in Fig. 3, which extend perpendicularly to the plane of Fig. 3 and transversely to the clearance between the members at the annular surfaces 9 and 10 so that the material undergoing comminution in its flow through the machine tends to pass from between adjacent rotor teeth 17 across the clearance between

teeth

17 and 18 and into the spaces between adjacent teeth 18 one or more times before passing out of the chamber 16.

On opposite sides of the narrow clearance-or working gap between the annular surfaces 9 and '10 the rotor and stator may be provided with insert rings and 24 atfixed bers or cavities, open only toward the working gap. They are limited in two dimensions and are similarly arranged on the facing

rings

15 and 24 with a linear distance on each of the rings of substantially the cavity width between successive cavities and between the rows of cavities.

The rotor is provided with an annular shoulder 19, and the stator has an annular rim in closely spaced relation with the shoulder 19. The rim and the shoulder define a further narrow gap between rotor and stator which extends in a direction parallel to the axis of the machine and through which the material under treatment fiows from chamber 16. At the end of the gap between the

cylindrical surfaces

19 and 20 remote from the chamber 16 the members 1 and 2 are provided with an additional pair of mating annular surfaces 21 and 22, which may also be set with insert rings, 23 on the rotor and on the stator. The surfaces of the

rings

23 and 25 are provided with concentric rows of depressions or cavities a and b, similar to the cavities a and b in the

insert rings

15 and 24. In embodiments of the invention which have them the groups of cavities a and b of the

rings

15, 24 and 23, 25 periodically change from positions of full coincidence to positions wherein the cavities a on the rotor are staggered with respect to the cavities b on the stator. The periodic rzhanges in pressure'imposed by this alternation on the material in the cavities a and b generate cavitational effects which disperse the 4 material. Adjustment of the speed of the'rotor, as by means of the rheostat 3 (Fig. 1) adjusts the frequency of the alternate confining and releasing action to the textural qualities of the material being treated so that the texrural strength thereof is disturbed by resonance effects. The

inserts

15,24, 21 and 23 with their cavities or depressions are however not necessary to all embodiments of the invention,'the scope of the invention being set forth in the appended claims.

What I claim is:

1. Method of producing very finely divided intimate mixtures such as dispersions, suspensions and emulsions and the like comprising the steps of subjecting the material to be treated to a sequence of changes of internal stresses effecting local implosions generated by moving it through a system consisting of narrow spaced gaps and roomy spaced exciter chambers opening only towards the gaps, said gaps and exciter chambers alternating with oneanother, and adjusting the frequency of alternation to the textural qualities of the material in such a way that its textural strength is disturbed by resonance efi'ects.

2. Method of producing very finely divided intimate mixtures such as dispersions, suspensions and emulsions and the like comprising the steps of subjecting the inaterial to be treated to a sequence of changes of internal stresses etfecting local implosions generated by moving it through a system consisting of narrow spaced gaps and subjecting the mixture to a sequence of changes of ining only towards the gaps, said gaps and exciter chambers alternating with one another, and adjusting the frequency of alternation to the textural qualities of the material in such a way that its textural strength is disturbed ,by resonance effects.

4. Apparatus for producing very finely divided intimate mixtures such as dispersions, suspensions, emulsions orthe like comprising rotor and stator members having cooperating faces relatively movable at high speed between which materials are fed for treatment, a central opening in one of saidrnembers through which the material is fed, one of said bodies having an annular shoulder defining a surface perpendicular to the axis of the bodies in a plane spaced from the major surface of the cooperating faces and the other of said bodies having an annular rim terminating in a surface in closely spaced relation with respect to the surface of said shoulder and said rim and shoulder defining a narrow working gap between the bodies extending in a direction parallel with the axis of the bodies,.the cooperating faces radially outward of said central opening defining a conical space for a substantial distance outwardly of the opening and a narrow working gap radially outward of said conical space, one of said bodies having an annular channel with a depth in excess of the Working gap and extending radially between said rim and said second mentioned narrow working gap, concentrically arranged spaced rows of teeth extending in alternate arrangement from the respective faces in a direction generally parallel with the axis of the rotor and the teeth of the rows of teeth having decreased extent outward of the opening, said teeth constitutinga shearing stage in the treatment of the material, the cooperating faces of said members having concentric rows of depressions therein'between the teeth and said annular cavity, radially extending teeth provided on the cooperating faces of the members within the confines of the annular cavity, and the cooperating facing surfaces of the rim and shoulder having additional concentric rows of depressions therein, all the depressions during relative movement of the members generating a sequence of outward of the central opening defines a conical space between the surfaces for a substantial distance outwardly of the opening, and a narrow working gap radially out-- ward of the conical space, concentrically arranged spaced rows of teeth extending in alternate arrangement from the respective facing surfaces in a. direction generally parallel with the axis of the rotor and the teeth of the rows of teeth having decreased extent in a radial direction outwardly of the central opening, said teeth constituting a shearing stage in the treatment of the material, and the cooperating surfaces further having concentric rows of depressions therein radially outward of the teeth whereby the depressions during relative movement of the members generate a sequence of changes of internal stresses effecting local implosions in the material to be treated as it passes between the cooperating surfaces.

6. Comminuting apparatus comprising two relatively rotatable members, each of said members having a surface conforming to a separate surface of revolution, said members being mounted for relative rotation with their said surfaces facing each other in coaxial relation, said surfaces being shaped to permit the mounting of said members with a narrow clearance therebetween at portions thereof displaced from their axis of relative rotation, one of said members being apertured adjacent the axis of relative rotation of said members for admission of a material to be comminuted to the space between said members radially inside said portions, a plurality of ring shaped arrays of projections arranged on each of said surfaces radially inside of said portions, an annular depression in one of said surfaces radially outside said portions, and a multiplicity of teeth arranged on each of said members to present a face to said depression, the

multiplicity of teeth on one of said members moving with close clearance past the multiplicity of teeth on the other of said members at faces of said teeth extending transversely to the flow of material through said depression.

7. Comminuting apparatus comprising two relatively rotatable members having substantially disk-shaped juxtaposed faces, at least one of said faces having a portion of concave shape, said members having each a plane annular portion radially outside the limit of said concave portion, one of said members having an annular cavity formed therein radially outside its annular portion, said members being shaped to have close clearance therebetween radially outside said cavity when supported with close clearance between said annular portions, each of said members having disposed radially inside its annular portion a plurality of circular arrays of teeth concentric with the axis of relative rotation of said members and projecting from its said face to the vicinity of the face of the other of said members, means supporting said members for relative rotation with close clearance between said annular portions, one of said members being apertured adjacent said axis of relative rotation for the supply of a material to be comminuted to the space between said members, and a multiplicity of teeth on each of said members having a face presented to the interior of said cavity,

the teeth of each of said multiplicities having an addi- '6 said multiplicities, said additional faces extending transversely of said plane annular portions. I

8. Comminuting apparatus comprising rotor and stator members, said members having unlike facing surfaces coaxial in the axis of relative rotation of said members, one

of said members being apertured adjacent said axis for the admission of material to be comminuted to the space between said surfaces, one of said surfaces having a concave portion, said surfaces each having radially outside said concave portion an annular portion, saidannular portions both conforming substantially to a single surface of revolution, means to support said members for relative rotation with close clearance between saidjannular portions,-a pluraliy of circular arrays of teeth arranged on each of said surfaces radially inside said annular portions, one of said members havin'g formed therein an annular cavity radially outside said annular portions, and a multiplicity of teeth on each of said members project ing into said cavity, the teethof one of said multiplicities being disposed'radially farther fromthe axis of relative.

rotation of said members than the teeth of the other of said multiplicities, the teeth of said multiplicities moving past each other with close clearance between faces thereof extending transversely to the clearance between said i annular portions.

9. Comminuting apparatu comprising rotor and stator members, said members having unlike surfaces coaxial in tbeaxis of relative rotation of said members, at least one of said surfaces'having a substantially conical concave portion, means to support said members for relative romembers, each of said teeth having a face presented to the interior of said cavity and a face presented to the teeth on the other of said members, said last-named faces ex:

tending transversely of the clearance between said members'at said outer limit. h 7 1 l0. Comminuting apparatus comprising rotor and stator members, said members having coaxial surfaces facing each other, one of said surfaces having a substantially 1 conical concave portion, the'other of said surfaces haying a substantially plane portion of the same diameter as said conical portion, said members having each an annular portion of the same shape radially positioned adjacent the radially outer limit of said conical portion, means to support said members for relative rotation about an axis in which said surfaces are coaxial with close clearance between said annular portions, one of said members being apertured adjacent said axis of relative rotation for the admission of a material to be comminuted to the space between said surfaces, a plurality of ring-shaped arrays of teeth disposed on each of said members radially inside said annular portions, the teeth of said arrays projecting from their respective members to pass with close clearance the facing coaxial surface of theother of said members, the arrays on one of said members alternating in radial position with the arrays on the other of said members, an annular depression in one of said members radially outside the annular portion of its said surface, said depression having as inlet the clearance between said annular portions and having as outlet a close clearance between said members angularly disposed with respect to the clearance between said annular portions, and amultiplicity of teeth on eachof said members disposed on opposite'sides of said outlet and projecting into said depression, the teeth of said multiplicities moving past each other with close clearance 7 between faces thereof extending transvcr ely of the clearance bptween said angular portions.

References Cited in the file of this patent UNITED STATES PATENTS 1,098,325 Kihlgrgan May 26, 1914 1,728,178 Eppegbagzh T Sept. 17, 1929 1,768,957 Johnson July 1, 1930 1,801,849 Cppnifi Apr. 21, 1931 1,807,773 Dawsog June 2, 1931 8 Black Aug. 30. 1932 Oste'rmann Noy.'1, 1932 Smhrland Mar. 31, 1936 Myers Nov. 2, 19,37 McCray L July 26, 19,38 Plauson Dec. 24, 1940 Bgiureschmid; May 26, 1942 Fishr Dec. 17, 1946 FQREIGN ATE T Great Bpitaip June 18, 1931

Claims

4. APPARATUS FOR PRODUCING VERY FINELY DIVIDED INTIMATE MIXTURES SUCH AS DISPERSIONS, SUSPENSIONS, EMULSIONS OR THE LIKE COMPRISING ROTOR AND STATOR MEMBERS HAVING COOPERATING FACES RELATIVELY MOVABLE AT HIGH SPEED BETWEEN WHICH MATERIALS ARE FED FOR TREATMENT, A CENTRAL OPENING IN ONE OF SAID MEMBERS THROUGH WHICH THE MATERIAL IS FED, ONE OF SAID BODIES HAVING AN ANNULAR SHOULDER DEFINING A SURFACE PERPENDICULAR TO THE AXIS OF THE BODIES IN A PLANE SPACED FROM THE MAJOR SURFACE OF THE COOPERATING FACES AND THE OTHER OF SAID BODIES HAVING AN ANNULAR RIM TERMINATING IN A SURFACE IN CLOSELY SPACED RELATION WITH RESPECT TO THE SURFACE OF SAID SHOULDER AND SAID RIM AND SHOULDER DEFINING A NARROW WORKING GAP BETWEEN THE BODIES EXTENDING IN A DIRECTION PARALLEL WITH THE AXIS OF THE BODIES, THE COOPERATING FACES RADIALLY OUTWARD OF SAID CENTRAL OPENING DEFINING A CONICAL SPACE FOR A SUBSTANTIAL DISTANCE OUTWARDLY OF THE OPENING AND A NARROW WORKING GAP RADIALLY OUTWARD OF SAID CONICAL SPACE, ONE OF SAID BODIES HAVING AN UNNULAR CHANEL WITH A DEPTH IN EXCESS OF THE WORKING GAP AND EXTENDING RADIALLY BETWEEN SAID RIM AND SAID SECOND MENTIONED NARROW WORKING GAP, CONCENTRICALLY ARRANGED SPACED ROWS OF TEETH EXTENDING IN ALTERNATE ARRANGEMENT FROM THE RESPECTIVE FACES IN A