Abstrict A mill or crusher useful for crushing and grinding material employing
mechanical vibratory drive force at a sonic frequency. A drive shaft
having orbiting eccentric weight means fixedly attached thereto
and having freedom of motion both rotationally and laterally is
rotatably driven by a drive motor to generate quadrature related
vibratory force components in the drive shaft. Rotatably supported
on the drive shaft by means of suitable bearings is a driving member
having mass (inductive) inertia in said sonic frequency range. A
"slave" member is freely supported on vibration isolation
members in external concentricity with the driving member so that
it is effectively in a "floating" condition, thus presenting
a mass reactance in said sonic frequency range. Material to be milled
or crushed is fed in the gap between the driving member and the
free-floating "slave". Cycloidal force is delivered from
the shaft to the driving member to precess or roll around on the
inside wall of the free floating slave member. Vibratory energy
developed in this gap effects grinding or crushing action on the
material fed therebetween.
Claims I claim:
1. A vibratory mill for grinding material comprising
a driving member,
eccentrically weighted drive shaft means for supporting said driving
member for freedom of motion rotationally about the longitudinal
axis of the drive shaft means,
means for suspending said drive shaft means for freedom of motion
laterally with respect to said longitudinal axis,
a slave member having an inside wall,
means for supporting said slave member in proximity to said driving
member and said slave member,
means for rotatably driving said drive shaft means to generate
cycloidal quadrature related vibratory force components therein,
said force components causing said driving member to both roll around
on and vibrate against the inside wall of said slave member, and
means for feeding said material into the gap formed between the
driving and slave member,
both shear and radial vibratory forces being applied to said material
to effect the grinding thereof.
2. The vibratory mill of claim 1 wherein said driving member and
said slave member are cylindrical, said slave member being in external
concentricity with said driving member, said gap formed therebetween
being annular.
3. The vibratory mill of claim 1 or 2 wherein said eccentrically
weighted drive shaft means comprises a drive shaft having eccentric
weight means attached thereto.
4. The vibratory mill of claim 3 wherein said eccentric weight
means comprises a pair of weights, one of said weights being attached
to a central portion of said shaft, the other of said weights being
attached to the end of said shaft.
5. The vibratory mill of claim 1 or 2 wherein the means for feeding
said material into the gap comprises a slinger disc fixedly attached
to said driving member and means for feeding the material to said
disc.
6. The vibratory mill of claim 5 wherein the slinger disc is attached
to said driving member near the top end thereof, said means for
feeding the material to said disc comprising an inlet spout located
above said slinger disc.
7. The vibratory mill of claim 5 wherein the material is fluid,
the slinger disc being attached to said driving member near the
bottom end thereof, said slinger disc having vanes on the bottom
surface thereof, the means for feeding said material to said disc
comprising an opening formed in the bottom of said slave member
opposite said disc, said vanes generating a suction which draws
the material upwardly through said opening.
8. The vibratory mill of claims 1 or 2 wherein said means for rotatably
supporting said driving member on said drive shaft means comprises
a pair of shaft bearings.
9. The vibratory mill of claims 1 or 2 wherein the material comprises
shale oil deposits in a well filled with liquid, said slave member
having studs distributed around the outer surface thereof, said
studs vibratorily impacting against the wall of said well as said
slave member is vibratorily excited by said driving member.
10. The vibratory mill of claims 1 or 2 wherein the means for supporting
said slave member comprises a housing and resilient mount means
for supporting said slave member in said housing.
11. The vibratory mill of claim 10 wherein the resilient mount
means are of rubber.
12. The vibratory mill of claim 1 wherein said drive shaft means
is flexible so as to permit said driving member to vary the extent
of its vibratory stroke during operation.
13. The vibratory mill of claim 12 wherein said drive shaft embodies
a universal joint assembly so as to provide said flexibility.
Description SPECIFICATION
This invention relates to relatively high frequency mechanical
vibratory crushing or milling or liquid cavitation processing, and
particularly to a device employing eccentric weight masses for generating
vibratory compression and expansion energy which is applied along
with shear and radial force components on work material or fluid
fed to a gap between an inductively excited vibratory driving member
and a free floating slave member concentric with the driving member.
The use of vibratory energy for crushing and grinding material
is well known in the art and is described in my U.S. Pat. Nos. 3284010;
3682397; 3473741; 3414203 3131878; and 3429512. The prior
art systems described in these patents generally employ inertial
members forming jaws between which the material to be crushed or
comminuted is fed, with one or both of these jaw members being independently
vibratorily driven by a resonant vibration system employing a mechanical
oscillator. An improvement over these prior art systems in the form
of a cycloidal sonic mill is described in my co-pending application
Ser. No. 228225 filed Jan. 26 1981. The advantages of crushing
action employing a whirling or rotary type wave action (two degrees
of freedom in quadrature) which is transmitted cycloidally to develop
radial force combined with shear force, is pointed out in my aforementioned
application Ser. No. 228225. In the device of this prior application,
a resonant vibration system is employed wherein the material to
be ground is fed between a first mass member which is cycloidally
driven against a second mass member.
The device of the present invention is a modification of the device
described in my aforementioned application Ser. No. 228225 which
involves a substantially simpler and more economical construction
and wherein the resulting force of the crushing or grinding action
is a three factor function of the direct interaction between a vibratory
inductive driving force and the inertial mass or inductive reactance
of a free floating slave member and the coupling characteristics
of the material being ground or crushed.
It has been found most helpful in analyzing the operation of the
device of this invention to analogize the acoustically vibrating
circuit involved to an equivalent electrical circuit. This sort
of approach to analysis is well known to those skilled in the art
and is described, for example, in Chapter 2 of Sonics, by Hueter
and Bolt, published in 1955 by John Wiley and Sons. In making such
an analogy, force F, is equated with electrical voltage E; velocity
of vibration u, is equated with electrical current i; mechanical
compliance C.sub.m, is equated with electrical capacitance C.sub.e
; mass M is equated with electrical inductance L; mechanical resistance
(friction) R.sub.m, is equated with electrical resistance R; and
mechanical impedance Z.sub.m is equated with electrical impedance
Z.sub.e.
Thus, it can be shown that if a member is elastically vibrated
by means of an acoustical sinusoidal force F.sub.o sin .omega.t,
(.omega. being equal 2.pi. times the frequency of vibration), that
##EQU1##
Just as in electrical circuitry, maximum acoustical energy can
be transferred from one circuit element to another where a good
impedance match exists, i.e., where the two elements have like impedance.
By observation of Equation 1 it can be seen that the impedance Z.sub.m,
is high where the force F.sub.o, is high, and velocity of vibration,
u, is relatively low.
The desired end results are achieved in the device of the present
invention by employing a shaft member having an eccentric weight
or weights fixedly attached thereto rotatably driven freely to orbit
in space so as to develop a cycloidal inductive force pattern of
predetermined force. Supported for relative rotation on this shaft
by means of rotor bearings is a driving member which has inertia
and which receives and radiates said inductive force pattern. Freely
supported in external concentricity with the driving member on vibration
isolator mounts is a vibratory slave member, a gap being formed
between the driving member and the slave member into which the material
to be ground or crushed is fed.
The predetermined vibratory exciting force generated in the shaft
member is coupled through the bearings to the driving member and
radiated from the driving member through the work material to the
slave member. The vibratory energy develops both radial and shear
vibratory forces in the work material, the shear forces effecting
rolling motion of the driving member around the wall of the slave
member. The sonic frequency rolling force transmitted to the slave
member from the predetermined maximum force of the eccentric weights
is a function both of the coupling characteristics of the work material
in the gap and also the mass (inductive) inertia of the slave member.
Thus, where the work material is harder, greater coupling is provided
with corresponding greater grinding force being developed, while
with softer materials a lesser degree of coupling is provided with
a resultant lower grinding force. Also, unlike conventional constant
stroke crushers, this device varies the stroke of the slave member
in response to the force limiting reactance. Thus, the device is
capable of automatically adjusting the grinding force and varying
the orbit and stroke of the reacting members as a function of the
nature of the work material and inductive reactance of the slave
member, to avoid the overginding of softer material yet providing
the needed grinding action where harder material is present without
overstressing the machine. This is a force limited device, not a
stroke limited design as in prior art machines.
It is therefore an object of this invention to provide an improved
mechanical crusher or miller wherein the force of the crushing and
grinding action is automatically regulated as a function of the
qualities of the work material and the mass (inductive) reactances
of the free elements of the device.
It is a further object of this invention to provide an improved
mechanical crusher or grinder employing vibratory grinding action
having both radial and shear cyclic grinding force components.
It is still a further object of this invention to provide a mechanical
vibratory crusher or mill wherein the grinding action is accomplished
in a gap formed between a freely vibratory and rotatably supported
driving member and freely mounted slave member with the coupling
between these two members being a function of the nature of the
work material.
Other objects of this invention will become apparent as the description
proceeds in connection with the accompanying drawings, of which:
FIG. 1 is an elevational view in cross section of a first embodiment
of the invention;
FIG. 2 is a cross-sectional view taken along the plane indicated
by 2--2 in FIG. 1;
FIG. 3 is a cross-sectional view taken along the plane indicated
by 3--3 in FIG. 1;
FIG. 4 is a cross-sectional view taken along the plane indicated
by 4--4 in FIG. 1;
FIG. 5 is an elevational view in cross section of a second embodiment
of the invention; and
FIG. 6 is a view taken along the plane indicaed by 6--6 in FIG.
5.
Referring now to FIGS. 1-4 a preferred embodiment of the invention
is illustrated. Hydraulic motor 16 is supported by means of upper
housing 21 on plate 22 which in turn is supported on main housing
26. The housing 26 which is cylindrical is supported on stand 42.
The drive shaft of motor 16 is coupled through universal joint 18
to shaft 20 this shaft thus being suspended from the drive shaft
16a of the motor for freedom of motion laterally. A slinger disc
45 has a hub portion 45a which is locked to the lower end of the
universal joint 18a by means of locking pin 38. Eccentric weight
members 30 and 32 are fixedly attached to shaft 20 by suitable clamp
portions thereof 30a and 32a respectively. Eccentric weight 32 is
located at the bottom of shaft 20 so as to cause rocking and slinging
action.
Driving member 10 is cylindrical in form and is rotatably supported
on shaft 20 by means of ball bearings 28a and 28b. Cylindrical slave
member 12 is freely supported in housing 26 on vibration isolation
members 40 which may be of rubber, this slave member being in external
concentricity with driving member 10 a gap 14 being formed between
the driving and slave members. A flared circular opening 15 is formed
at the top end of gap 14 to receive material to be ground or crushed.
Such material is fed in through inlet spout 50 from where it travels
through cylindrical upper housing member 21 to slinger disc 45 which
slings or sprays the material outwardly into tapered gap 15 from
where it enters annular gap 14 where the crushing and grinding operations
are performed. The crushed or milled material is fed out from the
bottom of gap 14 through outlet funnel 52 from which it is dispensed.
As already described, the material passed to the gap 14 is effectively
ground or crushed by the sonic frequency shear and radial forces
generated in the gap by virtue of the vibrational energy developed
as shaft 20 is rotated in sonic frequency range, along with the
eccentric weight members 30 and 32 which are attached thereto. Said
frequency range is typically 20 to 200 hz.
As has already been pointed out, the coupling and transmitted force
between driving member 10 and slave member 12 is affected by both
the mass (inductive) reactance of slave member 12 and the character
of the work material fed to gap 14; i.e., with harder material,
tighter coupling will occur. Driving member 10 has its stroke varied
by the coupling of the slave member. The slave member 12 tends to
apply its inductance to reduce the free stroke of driver 10. Driving
member 10 rolls around on slave member 12 at a rotary speed which
is a function of this coupling factor and the relative diameters
of members 10 and 12 the vibratory stroke of the slave member depending
upon its inductive reactance and the coupling provided by the work
material. Considering any vertical plane, during the first 180.degree.
of each vibration cycle the driving member acting through gap 14
tends to urge the slave member in one direction, and then in the
second 180.degree. of this vibration cycle in this plane, the driving
member tends to reverse the previously urged direction of movement
of the slave member, so as to greatly magnify the resulting force
applied to the work material in gap 14. The free hanging universal
joints 18 and 18a permit drive member 10 to vary its stroke. The
transfer of vibrational energy from housing 26 to motor 16 is minimized
by means of a circular rubber vibrational isolator mount 41 employed
in connecting upper cylindrical housing portion 21 to plates 22.
Referring now to FIGS. 5 and 6 a second embodiment of the invention
is illustrated, this second embodiment being adapted for use in
a liquid filled well bore for the in situ mining and processing
of oil shale or the like. In this second embodiment, the slave member
12 and the driving member 10 are supported within well bore 69 by
means of an elongated drive shaft 60 which may comprise a rotating
rod string suspended from a conventional swivel drive (not shown)
at the well head.
The pipe string 62 which is also conventionally supported from
the well head may be used to surround all or a portion of drive
shaft 60. Shaft 20 which has an eccentric weight member 30 fixedly
attached thereto by means of clamp 30a (as in the previous embodiment),
is coupled to shaft 60 by means of U-joint 65. Driving member 10
is rotatably supported on shaft 20 by means of ball bearing assemblies
28a and 28b, seals 29 being provided to prevent the liquid from
entering the space between shaft 20 and the inner walls of driving
member 10.
Slave member 12 is freely supported on the top portion of driving
member 10 by means of circular perforated plate 66 which abuts against
the top wall 10a of driving member 10. Gap 14 is formed between
the walls of driving member 10 and slave member 12 there being
fluid communication between this gap and the perforations 66a of
plate 66 such that fluid can freely pass from the gap into the
space above slave member 12. Well bore 69 is filled with liquid
75 which may comprise an oil-water mixture.
The housing of the first embodiment is eliminated and the outer
wall of slave member 12 has a plurality of drill bit inserts 64
which form hobnail type studs distributed around the outer surface
of the slave member. Slave member 12 also has an annular bottom
wall 12a which has an opening 74 formed in the central portion thereof.
A slinger disc 70 is fixedly attached to the bottom end of shaft
20 by means of pin member 73 which is fitted into the shaft through
the hub portion 70a of the disc.
In operation, shaft 20 is rotatably driven by shaft 60 to effect
the generation of vibratory force by virtue of eccentric weight
member 30 in the same manner as described for the previous embodiment.
Also, as for the previous embodiment, driving member 10 is caused
to roll around the wall of the slave member 12 as the driving member
rotates around on bearings 28a and 28b to cause shear and radial
vibrational energy to be developed in rotating crescent shaped gap
14 between these two members. In addition, the vibratory energy
developed in slave member 12 is transferred to drill bit studs 64
which operates to pulverize and loosen oil shale from the wall of
the well bore 69. The loosened material falling down from the wall
of the well into the surrounding liquid 75 (usually water) is swept
upwardly as indicated by arrows 72 by virtue of the circulatory
flow created by the vanes 71 of slinger disc 70 as this disc is
rotatably driven by the lower end of shaft 20. Circulatory flow
is directed through suction port 74 formed in wall 12a, from where
the flow is directed radially outwardly and into the widened gap
portions 15 as indicated by arrows 78.
In this manner, the material that is cut loose from wall 69 is
caught up and caused to pass upwardly through treatment gap 14
where it is vibratorily ground as described in connection with the
first embodiment. Oil particles which are separated from the shale
rise by gravity in the liquid in the well (typically water) to the
top of the well where it can be removed.
The rotation induced in member 12 submerged in the fluid tends
to hold the entire assembly radially outwardly against the ever
increasing diameter of the well bore (by virtue of Bernoulli effect).
The well bore thus can be mined in place and enlarged to a bottle
shape which can have relatively large diametered portions in its
lower region. If desired, the bottom sand filled portion of a well
can be reprocessed for final recovery of trace oil which may be
trapped in stray grains of shale, by lowering this assembly so that
the bottom suction opening 74 is submerged into the wet sand which
can be sucked up by the vacuum action engendered by vane 71 so
as to deliver the sand up through gap 14 in the same general manner
as just described.
Liquid filled annular gap 14 as in the previously described embodiment
presents a spring-like (capacitive) response to the masses (inductances)
presented by masses 10 and 12 so that, if so desired, a resonance
can be attained in a definitive frequency range. The frequency of
resonance can be determined in the design of the device by varying
the thickness of the gap 14 (liquid spring layer) and by varying
the masses of members 10 and 12. Where resonant operation is employed,
very large pressure swings occur in the liquid gap 14 which can
include cavitation effects which aid in the comminution of the oil
shale and the laundering of oil therefrom.
While the invention has been described and illustrated in detail,
it is clearly to be understood that this is by way of illustration
and example only and is not to be taken by way of limitation, the
spirit and scope of this invention being limited only by the terms
of the following claims. |