CA1225976A - Cycloidal sonic mill for comminuting material suspended in liquid and powered material - Google Patents

Abstract

#1601 CYCLOIDAL SONIC MILL FOR COMMINUTING
MATERIAL SUSPENDED IN LIQUID AND POWDERED MATERIAL
ABSTRACT OF THE DISCLOSURE
An annular treatment chamber is formed by a gap between inner and outer inertial ("inductively reactive") members. At least one of these members, typically the inner one, is vibratorily driven cycloidally in an orbital path, which is typically circular or elliptical, at a frequency of the order of 50-500 cycles per second The granular material to be comminuted may constitute material suspended in a liquid or may be in particle form. This material is continually fed into the annular gap and exited therefrom after comminution has been accomplished. While in the annular gap, the material is driven circumferentially around the annular chamber with a high shear force while being subjected to radial vibratory forces developed therein. The fluid material is thus simultaneous-ly subjected to high forces of cyclic nature having both shear and radial components which tends to effect cavitation in liquids and high comminution forces in powdered material to effectively commin-ute both types of material in the case of liquid material, effec-tively comminuting the solid particles into a colloidal suspension in the liquid.

Description

` ¦ ~160 ~æ5~6 1 ¦ CYCLOIDAL SONIC MILL ~OR COMMINUTING

2 ¦ MATERIAL S~SPENDED IN LIQUrD AND POWDERED MATERIAL

3 1

4 ¦ S P E C I F I C A T I O N

5 ¦ This invention relates to sonie mills for eomminuting mate-

6 ¦ rial suspended in liquid or granular material, and more partieular-

7 ¦ ly to sueh a deviee and method wherein the comminution is aecom-

8 ¦ plished in an annular gap by means of cyeloidal vibratory energy

9 ¦ having both shear and radial foree eomponents.

10 ¦ Sonie energy has been employed successively in erushing and

11 ¦ comminuting material, as described in my U. S. Patent Nos.

12 ¦ 3,284,010; 3,682,397; 3,473,741; 3,414,203; 3,131,878; and

13 ¦ 3,429,512. These prior art systems have generally employed inertial

14 ¦ members forming jaws between which the material to be erushed or

15 ¦ comminuted is fed with one or both of these jaw members being

16 ¦ independently vibratorily driven by a resonant vibration system

17 ¦ employing a meehanical oscillator. In all of these independent

18 ¦ jaw systems, only s~ueezing vibratory forces are employed whieh,

19 ¦ while effeetive for erushing roek and the like, does not produee

20 ¦ the eomminution effect needed in certain application requirements,

21 ¦ sueh as the cyeloidal comminution of solid material into a eolloidal 2~ ¦ suspension in a liquid or the comminution of dry partiele material 23 ¦ into relatively fine powder, such as in the eomminution of diato-2~ ¦ maceous earth. Further, in most of these prior art deviees, sueh 25 ¦ as that shown in the 3,429,512 and 3,414,203 patents, the inertial 26 ¦ member to whieh the vibratory system is coupled has a very high 27 ¦ mass and thus is limited in amplitude of total motion. Moreover, 28 ¦~ it is difficult to maintain a fixed gap or to have one centrally 30 ~ driven jaw excite a second inertial jaw with a fixed gap.

32 ~7 1 ¦ The device and technique of the present invention is based 2 ¦ on the inventor's discovery that a whirling or rotary-type wave 3 ¦ action (two degrees of freedom in quadrature~ which is transmitted 4 ¦ cycloidally from a resonant vibration system employing an elastic ~ ¦ member through a solid inertial member to an annular gap will 6 ¦ develop a very high radial force combined with a very high shear 7 ¦cyclic vibrating circumferential force capable of cavitating a 8 ¦li~uid material and comminuting a granular material in the gap.
9 ¦At any point along the annular gap, a powerful cyclic radial sonic 10 ¦compression and expansion in the fluid is produced as the gap opens 11 ¦and closes in response to the raaial components of the cyclic 12 ¦force. Simultaneously, a large fluctuation in fluid shear stress 13 ¦is developed as the crescent shaped gap pulsates and progresses 14 circumferentially around the gap at high speed, the fluid "squish-ing" around the annulus vibratorily.
16 In the case of liquids, the radial vibratory orces cooperate 17 with the shear forces to induce a high level turbulent shear flow 18 to aid in the formation of cavitation bubbles, the cavitation 19 causing viscosity effects which has significant effect on the shear flow.
21 If it is desired to comminute solid material into a colloidal

22 suspension in a li~uid, the two materials can be placed into the

23 annular gap with the implosion of the cavitation causing the li~uid 2~ to "soak" or penetrate the solid particles and break them apart with the cyclically shear stresses and vibratory impact further 26 comminuting the soaked particles. Such action also occurs where 27 dry particles alone are the work material to efficiently effect 29 comminution thereof.

1 ¦ It is therefore an object of this invention to facilitate 2 ¦ the comminution of particulate material.
3 ¦ It is a further object of this invention to provide improved 4 ¦ apparatus and technique employing cycloidal sonic vibratory action 5 ¦ for comminuting material in an annulus formed between a pair of 6 ¦ inertial members.
7 ¦ Other objects of this invention will become apparent as the 8 ¦ description proceeds in conjunction with the accompanying arawings 9 ¦ of which:
10 ¦ FIG lA is a cross-sectional view in elevation of a first 11 ¦ embodiment of the invention;
12 FIG lB is a cross-sectional view, taken along the plane 13 indicated by lB-lB, in FIG l;
14 FIG 2 is a cross-sectional view in elevation of an alterna-tive form of the annular gap chamber which may be employed in the 16 device of the invention;
17 FIG 3 is an elevational view in cross section of a second 18 embodiment of the invention;
19 FIG 4 is an elevational view in cross section of an alterna-tive form for the annular chamber employed in implementing the 21 invention;
22 FIG 5 is an elevational view in cross section of a modified 23 form of the annular chamber employed in the embodiment of FIG 3;

24 FIG 5A is a cross-sectional view taken along the plane indi-cated by 5A-5A in FIG 5;
26 FIG 6 is a side elevational view of a further embodiment of 27 the invention;
28 FIG 6A is an end elevational view of the embodiment of FIG 6 2g shown partly in cross section 1 ¦ FIG 6B is a cross-sectional view taken along the plane indi-2 ¦ cated by 6B-6B in FIG 6;
3 ¦ FIG 7 is a top plan view of an alternative form of the outer 4 ¦ inertial mass member which may be employed; and 5 ¦ FIG 7A is a cross-sectional view taken along the plane indi-6 ¦ cated by 7A-7A in FIG ~O
7 ¦ It has been found most helpful in analyziny the operation of 8 ¦ the device of this invention to analogyze the acoustically vibrat-9 ¦ ing circuit involved to an equivalent electrical circuit. This 10 ¦ sort of approach to analysis is well known to those skilled in the ll art and is described, for example, in Chapter 2 of "sonics" by 12 Hueter and Bolt, published in 1955 by John Wiley and Sons. Xn 13 making such an analogy, force F is equated with electrical voltage 14 E, velocity of vibration u is equated with electrical current i, mechanical compliance Cm is equated with electrical capacitance 16 Ce, mass M is equated with electrical inductance L, mechanical 17 resistance (friction) Rm is equated with electrical resistance R, 18 and mechanical impedance Zm is equated with electrical impedance 19 Ze Thus, it can be shown that if a member is elastically vibratec ~1 ¦by means of an acoustical sinusoidal force, Fo sin ~t (~ being 22 ¦ equal to 2~ times the frequency of vibration), 2~ m m i(~ ~Cm~ u (1) 26 ¦ Where ~M is equal to l/~Cm, a resonant condition exists, and 27 ¦ the effective mechanical impedance 2m is egual to the mechanical 2.8 ¦resistance Rm, the reactive impedance components ~M and l/~Cm 29 ¦cancelling each other out. ~nder such a resonant condition, 32 l l -4-~ ~2~
1 ¦ velocity of vibration u is at a maximum, power factor is unity, and ¦ energy is most efficiently delivered to a load to which the reson-3 ~ ant system may be coupled.
4 ¦ It is to be noted that in the device of this invention the 5 ¦ mass and compliance for ~orming the resonantly vibrating system are 6 ¦furnished by the structural members of such system themselves so 7 ¦that the work material and the inertial member are not incorporated 8 ¦as reactances in such system. The work material under such condi-9 ¦tions acts as a resistive impedance load which provides no signi-10 ¦ficant reactive components, while the inertial mem~er is coupled 11 ¦to the work material as primarily a high-mass load which remains 12 ¦substantially inert. This employment of apparatus resonance re-13 ¦sults in a random vibration of the particles of the work material 14 rather than a lumped coherent vibration such as results from non-resonant vibrating apparat&s, with a considerable relative motion 16 occurring between the separate particles. It is believed that each 17 of the individual particles when energized by the sonic energy in 18 this sonic resonant fashion separately vibrates in a random path 19 with a relatively fixed radius of vibration which changes in direc-tion but remains fixed in magnitude. Such random vibration effec-21 ~ively separates the particles so that they do not adhere to each 22 other~ The net result is a uniquely high degree of fluidization ~3 of such particles which effectively aids in the separation of the 2~ fully ground material from that requiring additional comminution.
It is also important to note the significance of the attain-26 ment of high acoustical Q in the resonant system being drivenr to ~7 increase the efficiency of the vibration thereof and to provide a 28 maximum amount of energy for the grinding operation. As for an 29 equivalent electr;cal circuit, the Q of an acoustically vibrating circuit is def;ned as the sharpness of resonance ~hereof and is ~1 indicative of the ratio of the energy stored in each vibration 1 ¦ cycle to the energy used in each such cycle. Q is mathematically 2 ¦ e~uated to the ratio between ~M and ~Rm. Thus, the effective Q
3 ¦ of the vibrating circuit can be maximized to make for highly effi-4 ¦ cient, high-amplitude vibration by minimizing the efect of friction ¦ in the circuit and/or maximizing the effect of mass in such circuit.
6 ¦ Of significance in the impiementation of the method and 7 ¦devices of this inven~ion is the high acceleration of the components 8 ¦of the elastic resonant system that can be achieved at sonic fre-9 ¦quencies. The acceleration of a vibrating mass is a function of the 10 ¦square of the frequency of the drive signal times the amplitude of 11 ¦vibration. ~his can be shown as follows:
12 ¦ The instantaneous displacement y of a sinusoidally vibrating 13 mass can be represented by the following equation:

y = ~ cos ~t (2) 17 here Y is the maximum displacement in the.vibration cycle and 18 is equal to 2~f, f being the frequency of vibration.
19 The acceleration a of the mass can be obtained by differen-tiating Equation 2 twice, as follows:

~1 22 a = d Y = _ y~2 cos(~t) (3) 23 dt2 2~ t resonance, Y is at a maximum and thus even at moderately high sonic frequencies, very high accelerations are achieved making for 26 correspondingly high cycloidal vibrational forces on the work :
27 material.
28 In considering the significance of the parameters described 29 in connection with Equation 1, it should be kept in mind that the 1 ¦total effective resistance, mass, and compliance in the acoustically 2 ¦ vibrating circuit are represented in the e~uation and that these 3 ¦ parameters may be distributed throughout the system rather than 4 ¦ being lumped in any one component or portion thereo~.
5 ¦ Referring to FIGS 1 and lB, a first embodiment of the inven-6 ¦ tion is illustrated. Eccentric rotor 12 is mounted on drive shaft 7 ¦10a of hydraulic motor 10 within housing 14, the rotor and housing 8 ¦forming an o~biting mass oscillator. Hydraulic motor 10 is clamped 9 ¦to housing 14 by means of bolts 16. The housing is preferably made 10 ¦from a material such as aluminum to make for a low mass, thus keep-11 ¦ing its acoustic "inductance" effect down. Housing 14 is clamped `
12 ¦to elongated elastic bar member 20 by means of squeeze bolts 18, 13 the bar being made of a highly elastic material, such as steel. A
14 snap ring 26 is installed over the top end-of elastic bar 20 to aid in supporting the load of the bar and the members attached 16 thereto on housing 14.
17 Inner mass member 30, which forms an "inductive" reactance 18 in the vibratory system, fits over the bottom portion of elastic 19 bar member 20 and is prevented from falling therefrom by snap ring 28. Outer mass member 32, which also forms an "inductive" reac-21 tance in the vibration system, is supported loosely on inner mass 22 member 30 by virtue of the engagement of the opposing inner conical 23 surface of member 32 and outer conical surface of member 30. Outer 2~ mass me~ber 32 may be divided into three separate cylindrical sec-tions 32a, 32b and 32c, this to amerliorate the tendency of the 26 outer mass member to bounce excessively on occasion. Ring sleeve 27 38 is mounted on the top edge of member 32 by means of shoulder 28 ring 40 and damper ring 42 which is placed thereunder, these rings 29 being retained on the sleeve by means of bolts 44. Splash guard 1 ¦ sleeve 46 of a resilient material such as rubber is retained to the 2 ¦ ring sleeve by means of clamp band 48. A work material, such as 3 ¦ powder to be comminuted or a powder-liquid mixture in which the 4 ¦powder is to be formed into a colloidal suspension, are fed into 5 ¦the receptacle formed by the inner walls of the top portion 32c of 6 ¦mass member 32 through conduit 50. This material runs into annular 7 Igap 36 formed between inner and outer mass members 30 and 32 respec-8 ¦tively, ana is finally discharged from the lower edge of the gap.
9 ¦The entire assembly is suspended by means of a cable 53 which is .
10 ¦fitted through eye member 8 attached to the outer wall of motor 10.
11 ¦ Typically, the work material 54 may be a diatomaceous earthen 12 ¦material to be comminuted or coal particles which are mixed with a 13 ¦liquid to be colloidally suspended therein for use as heating oil.
14 The device of the invention operates as follows: High speed hyaraulic motor 10 rotatab~y drives oscillator rotor 12 to generate 16 vibratory energy which is delivered through the bearings of the 17 motor shaft lOa to oscillator housing 14. This energy in turn is 18 elivered from the housing to elastic cylindrical bar member 20.
19 The speed of rotation of rotor 12 is adjusted to a frequency whereat ~0 esonant vibration of bar member 20 occurs in a lateral rotary 21 ave vibrational mode which can be resolved into a pair o~ quadra-22 ture lateral force vectors. The standing wave vibrational pattern ~3 ~ bar member 20 is indicated in a sinyle plane by graph lines 24 ~ ith the nodal points of the vibratory pattern beiny indicated at 24a and the antinodal points being indicated at ~4b.
26 This whirling wave transmission down bar ~0 causes the ~7 lower end thereof to bend around with cycloidal circular motion 31, 28 as indicated in FIB lB, so that mass member 30 vibrates in a 29 pattern whereby every part thereof describes a closed orblt, such 1 ¦ as a circle or ellipse. As to be noted from the graph pattern 24, 2 ¦ large cyclic force is maintained in the gap area by virtue of the 3 ¦ resonant vibration pattern. The gap 36 between the inner and outer ¦ mass members takes the form of a crescent which ~eometric crescent 5 ¦effectively rotates cycloidally in its orientation at the vibra-6 ¦tion frequency. Thus, in any one instance, the gap is at a minimum 7 lon one side and a maximum at the other side. This results in a 8 ¦circumferential shear velocity of the work material 54 around the 9 Igap. At the same time superimposed on this cycloidal annular pump-lO ¦ing action of the work material there is a radial ~ibratory action 11 due to the expansion and contraction of the gap at each and every 12 point therearound.
13 It is important to note that the ma~s inertial member 32 14 effectively acts as a seismic reactance in space. Its motion or stroke is variable and the-reactance force created against inner 16 mass member 30 and the latter's attempt to accelerate the mass 17 reactance of member 32 always in opposed direction are all subject 18 to values o~ 32 alone as a dynamic reactance inertial seismic mass 19 in space. There are no equal and opposite reaction stresses taking ~0 place through any interconnecting structure. Mass member 32 ef-~1 ~ectively "floats in space" and generates the desired milling forces 22 by its dynamic interaction through mass member 30 and bar member 23 20 with the orbiting "inductive" mass of rotor 12. Member 30 24 "throws" the mass 32 first in one direction and then meets it in opposition on the other side of the gap. The crushing stresses are 26 thus limited solely by the inertial reactance of mass members iO and 27 32 and no large enveloping machine structure is subjected to high 28 stress as in conventional crushers. Controlled cyclic force rather 29 than controlled fixed cyclic stroXe is employed, and this is accom-31 lished with high frequency vibration~

_g_ ~2ss~i 1 ¦ Referring now to FIG 2, an alternative configuration or the2 ¦ mass members 32 and 30 of the invention is illustrated~ In this 3 ¦ embodiment, the inner walls of mass members 30 and 32 are cylindri-4 ¦ cal rather than conical. Further, a per~orated support plate 39 5 ¦is provided to support outer mass member 32 on shaft 20 in conjunc-6 ¦tion with snap ring 28. A rubber cushioning ring 58 is provided 7 ¦between mass member 32 and support plate 39. The gap 36 is thus 8 ¦fixed and does not vary as in the previous embodiment wherein the 9 ¦outer mass member rises automatically due to the vibration to create lO ¦the gap between the inner and outer mass members. This particular 11 ¦configuration has advantages with certain types of work material 12 ¦having liquid present wherein pressure confinement is an advantage.
13 In this configuration, the work material, after having passed 14 through gap 36, is exited through perforations 39a formed in the support plate.
16 Referring now to FIG 3, a second embodiment of the invention 17 is illustrated. This embodiment, rather than employing suspension 18 means with the device, utilizes a stand with the units being assem-1~ bled in a compressive type arrangement. Outer mass member 32 is cylindrical in configuration and is carxied on spring suspension 21 assembly 50 which comprises a plurality of coil springs 50a which 22 are supported on pillars 50b which in turn are supported on the ~3 base of stand 60~ Outer mass (inductive reactance) member 32 has 24 a replaceable cylindrical liner sleeve 32a which has an annular shoulder 32c which rests on the top surface of the main body por-26 tion of the inertial mass member 32. Inner mass member 3~ may: be 27 formed by a hardened steel roller which rests on shoulder portion 28 32b of the sleeve. Insert member 52 rests on the top surface o~
2~ mass member 30 and supports elastic bar member 20 on this mass 5~6 1 ¦ member. Elastic bar 20 is fitted closely in insert 52 with its 2 ¦ walls in engagement against the walls of the insert and with the 3 bottom thereof abutting against annular shoulder 52a of the insert,.
4 ¦ the insert having a cylindrical configuration for its inner wall.
~ ¦ The externally conical shape of the upper portion of insert 52 6 ¦ is particularly effective for crushing any large chunks in the 7 ¦ input load.
8 ¦ The sonic oscillator is of the same basic configuration as 9 ¦ that of the first embodiment and has a housing 14 which is tightly lO ¦ clamped to the top end of elastic bar 20 by means of clamp fitting 11 ¦ 62. As for the first embodiment, the oscillator has an eccentric 12 ¦rotor (not shown) mounted within the housing 14 which is rotatably 13 ¦driven by motor 10. In this second embodiment, the motor 10 is 14 ¦mounted on the top structure 60a of support stand 60 and is coupled 15 ¦to the oscillator rotor by means of a conventional universal joint 16 ¦and drive shaft assembly 54. The work material is fed into the 17 ¦receptacle formed by liner sleeve 32a by means o pipe 50 and 18 ¦outletted from the bottom end of the mill through ~utlet funnel 65, 19 ¦after having been comminuted or placed in colloidal suspension (as 20 ¦~he case may be) by virtue of the action thereon in gap 36. Outlet 21 ¦~unnel 65 is supported by means of rubber flange 65a which is 22 ¦attached to the outer wall of the funnel and supported between 23 ¦springs 50a and the bottom surface of inertial mass member 3~.
2~ ¦ This second embodiment operates in the same general manner

25 ¦as the first embodiment in comminuting powdered material or placing

26 ¦material in colloiaal suspension in a li~uid by virtue of the cy-

27 ¦cloidal sonic energy developed in the gap 36 between inner inertial

28 ¦mass member 30 and outer inertial mass member 32. The conical ~9 ¦ shape of insert 52 is effective in a preliminary way to break up 31 any large chunXs so that all material can flow into gap 36 ~ 76 1 ¦ Referring now to FIG 4, a variatiOn in the structural con-2 ¦ fi~uration of the inner and ou~er mass members of the embodiment 3 ¦ of FIGS 2 or 3 is shown. In this embodiment, the gap 36 is conical-4 ¦ ly shaped with the gap width increasing in the downward direction 5 ¦ to provide a clearance shape aro~nd member 30 that somewhat corre 6 ¦ sponds to the shape of the conical vibrational wave pattern 24 7 ¦ below its nodal region 24a (see FIG 1). The lower portion of the 8 ¦ driven inertial mass member 30 thus is free to describe a greater 9 ¦ cycloidal amplitude than does the upper region thereo~, to enhance 10 ¦ the freedom of the wave pattern. Moreover, the progressively 11 ¦ enhanced vibration amplituae in a downward direction of the gap 12 ¦ results in a downward pumping effect which increases the through-13 ¦ put of the device. In this embodiment, as in the embodiment of 14 ¦ FIG 1, the bottom end of elastic bar member 20 is retained to inner 15 ¦ mass member 30 by means of snap ring 28. As with the embodiment 16 ¦ of FIG 3, the outer inertial mass member 32 is supported on a 17 ¦spring suspension 50. .
18 ¦ Referring now to FIGS 5 and 5A, a further variation for the 19 ¦milling portion of; the device o~ FIG 3 is shown. In this varia-~0 ¦tion, outer inertial mass member 32 has an inner wall which forms 21 la cone which runs inwardly in a downward direction at a relatively 22 ¦wida angle to form a gap 36 between it and the opposing walls of 23 ¦inner inertial member 30. Elastic bar member 20 fits tightly 24 ¦within a mating cavity formed in the center of inertial mass member 25 130. Ribs 56 are formed around member 30 to define fluted passages 26 ¦ therebetween which aid in increasing the rate of throughput.; The 27 ¦use of such a wide angle conical gap between the inertial mass 28 ¦members tends to provide stability to the system in situations ~9 ¦ where the work material tends to cause a gripping effect between l -12-~i~76 1 ¦ the members with resultant vertical climbing of one of such 2 ¦ members.
3 ¦ Referring now to FIGS 6, 6A and 6B, a further embodiment of 4 ¦ the invention employing a stand for supporting the milling device ~ ¦ in compression is illustrated; ~n this embodiment! as for the 6 ¦ embodiment of FIG 3, the operating mechanism is supported on a 7 ¦stand 60. Elastic bar member 20 is welded to flange 71 at its 8 ¦top end~ Oscillator housing 14 is similarly welded to flange 72 9 ¦which is bolted to flange 71. Oscillator motor 10, which may be 10 ¦an hydraulic motor such as for the first described embodiment, 11 ¦rotatably drives the eccentric oscillator rotor (not shown) mounted 12 ¦within oscillator housing 14 to develop cycloidal vibratory energy 13 ¦which is transferred to elastic bar member 20 as for the previous 14 ¦embodiments. Elastic bar member 20 is loosely fitted through guide 16 ¦bushing 70 which is fixedly supported on stand 60. The bottom end 16 ¦o~ elastic bar member 20 rests on a support cup member 74 which 1~ ¦in turn is supported on support ball member 75, the ball member 18 ¦resting on support plate 77, which is fixedly attached to support 19 ¦ar~ 78 of the frame. Ball member 75 is only loosely confined 20 ¦within cup member 74 to ensure that the annular gap 36 can freely 21 ¦respond dimensionally to the vibratory energy. Inner inertial mass 22 ¦member 30 is generally cylindrical in shape and is supported on 23 ¦shoulder 74a of the cup member. The non-driven outer inertial mass 24 ¦member 32, which is rectangular in shape, is supported on an 25 ¦elastic rubber mount 80. As for the embodiment of FIG 3, outer 26 ¦inertial mass member 32 has a liner sleeve 32a which serves as a 27 ¦receptacle for receiving the work material fed thereto from inlet ~8 ¦pipe 50. As for the previous embodiments, this work material is 30 ~fed to gap-36 formed be~ween inner inertial mass member 30 and ~1 ~2 ~5976 1 ¦ outer inertial mass member 32 where it is cycloidally comminuted 2 ¦ or placed in a colloidal suspension in a liquid, as the case may 3 ¦ be.
4 ¦ Referring now to FIG 7, an alternative form for the outer ~ ¦ inertial mass member is sho~n. Inertial mass member 32, which may 6 ¦ be used for example with ~he system shown in FIG 4~ has outer 7 ¦ holding sleeve 32d tightly holding a set of radially oriented 8 ¦ inner ribs 32e. Open gaps 36a provide radially expanding passages 9 ¦ between ribs 32e ~or the quick release and dropping of sized mate-10 ¦ rial thus forming the output.
11 ¦ In operation, the work material moves downward and is com-12 ¦ minuted or crushed at the inner edyes of ribs 32e in gap 36 as 13 above described until the material reaches a predetermined particle 14 size whereupon the so sized particles escape easily radially and downwardly through geometrically expanding passages 36a rather than 16 becoming overly crushed by further downward progression in gap 36 17 along the inner edges of ribs 32e. There are many uses for sized 18 particles, such as coal feed for the well known retorting processes 19 (where-"fines" cause trouble) and limestone in animal feed.
In considering certain characteristics of this invention it 21 i5 important to note, for example, that inertial member 32 is 22 alternately forced from one side so to speak to the other by member ~3 30 acting against member 32. The gap is thus never thrown widely 24 open by excursions in space of member 32, because the excursions of member 32 are always met by subsequently opposed excursions of 26 member 30 going momentarily (180 in time later) in the opposite 27 direction on the other side of the gap 36 during the cycle. Thus, ~8 member 30 throws member 32 back and forth, developing large contact

29 forces of cyclic acceleration, and assuring that the gap 36 stays 9~æ5976 1 ¦ small for fine comminution. The actual vibratory excursions of 2 ¦ member 32 are therefor in part a function of the crushing force in 3 ¦ the materiai in gap 36. Whereas conventional crushers usually 4 ¦ have a fixed stroke and therefore uncontrolled varia~le force in ~ ¦ the work material, the device of this invention subjects the mate-6 ¦ rial to a controlled cyclic force which is a function of the sonic 7 ¦ acceleration and mass of member 32; and the actual stroke of mem-. 8 ¦ ber 32 is variable, depending in part upon ~he hardness of the 9 ¦ work material which is transmitting the sonic`acceleration forces from member 30 to member 32.
11 While the invention has been described and illustrated in 12 detail, it is to be clearly understood that this is intended by 13 way of illustration and example only and is not to be taken by 14 way of limitation, the spirit and scope of the invention being 16 ¦ li ted only by the terms of the iollowing olaims.

8 .

32 ~ -15-

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

A sonic milling device comprising an elastic member, oscillator means for generating vibratory energy having a cycloidal force pattern which can be resolved into a pair of quadrature related, lateral force vectors, means for coupling said cycloidal force pattern energy to said elastic member, a first inertial mass (inductively reactant) member connected to said elastic member to receive the cycloidal energy therefrom, said first inertial mass member having a predetermined working surface, a second inertial mass (inductively reactant) member having a predetermined working surface directly opposite the working surface of the first inertial mass member, an annular gap having inlet and outlet portions being formed between said working surfaces, and means for delivering work material to the inlet portion of said gap, said work material being simultaneously subjected to cyclic radial forces and shear forces in the annular gap between said working surfaces, said work material being exited from the outlet portion of said gap after having passed there-through.

The milling device of Claim 1 wherein the vibratory energy generated by said oscillator is at a frequency such as to cause resonant elastic vibration of said elastic member.

The milling device of Claim 1 wherein said elastic member comprises an elongated elastic bar member.

The milling device of Claim 1 wherein at least one of said working surfaces is conical.

The milling device of Claim 1 wherein both of said working surfaces are cylindrical.

The milling device of Claim 1 wherein both of said working surfaces are conical.

The milling device of Claim 1 wherein the gap increases in width between the inlet and outlet portions thereof.

The milling device of Claim 1 wherein the second inertial mass member is externally concentric with said first inertial mass member.

The milling device of Claim 8 wherein the working sur-face of the second member is conical and slopes inwardly at a relatively wide angle towards the outlet portion of said gap.

The milling device of Claim 9 and further including a plurality of ribs extending outwardly from said first inertial mass member, fluted passages being formed between the ribs to facilitate the flow of said work material to said gap.

The milling device of Claim 1 and further including means for suspensively supporting said device with said elastic member being suspended from said oscillator means and said mass members being suspended from said elastic member.

The milling device of Claim 11 wherein said second inertial mass member is externally concentric with said first inertial mass member, the working surfaces of said mass mem-bers both being conical, the second mass member being supported loosely on said first mass member by virtue of the engagement of said working surfaces.

The milling device of Claim 1 and further including stand means for supporting said device comprising means for resiliently supporting said second inertial mass member, said first inertial mass member being internally concentric with said second mass member, said elastic member being connected to the first mass member and said second mass member being loosely held against said first mass member.

The milling device of Claim 13 wherein said means for resiliently supporting said second mass member comprises coil spring means supported on said stand means.

The milling device of Claim 13 and further comprising ball support means mounted on said stand means, said elastic member comprising an elongated bar supported at its lower end on said ball support means.