Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
` ¦ ~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.
31
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.
32
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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
31
32
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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,
31
32 l
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~ ~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
32
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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:
14
y = ~ cos ~t (2)
16
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
31
32
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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
31
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
31
32
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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~
32
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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
32
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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
32 1
~ 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
31
32 1
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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
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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
31
32
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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 .
21
26
28
31
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