U.S. patent number RE33,752 [Application Number 07/276,982] was granted by the patent office on 1991-11-26 for apparatus for the separation of mixtures of materials of different consistencies such as meat and bone.
Invention is credited to Werner Poss.
United States Patent |
RE33,752 |
Poss |
November 26, 1991 |
Apparatus for the separation of mixtures of materials of different
consistencies such as meat and bone
Abstract
Apparatus for the separation of mixtures of materials of
different consistencies, such as meat and bone, or sewage
containing solid material, comprises a positive displacement pump
feeding the pressurized mixture to a separator .Iadd.screen
.Iaddend.which can be separate from the pump or an integral part of
its structure. The pump comprises a rotary vaned pump with
radially-moving vanes of fixed length operating with both their
ends always in sealing engagement with the wall of an internal cam
also constituting a wall of the pump chamber. The vanes are
provided with cutting edges able to shear material such as bone
that enters the pump, so that the pump is not jammed thereby.
.Iadd.The pump is required to provide pressurization to the mixture
of at least 70 Kg/sq. cm. (1000 p.s.i.), usually up to about 210
kg/sq. cm. (3000 p.s.i.) to obtain adequate separation; the
separator screen and outlet must be able to provide for
corresponding back pressures in the pressurized mixture again to
obtain adequate separation. .Iaddend.
Inventors: |
Poss; Werner (Oakville-Ontario,
CA) |
Family
ID: |
26958244 |
Appl.
No.: |
07/276,982 |
Filed: |
November 28, 1988 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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513487 |
Jul 13, 1983 |
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Reissue of: |
690215 |
Jan 10, 1985 |
04638954 |
Jan 27, 1987 |
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Current U.S.
Class: |
241/74; 241/89.3;
209/262; 241/247; 209/300; 241/260.1 |
Current CPC
Class: |
A22C
17/04 (20130101) |
Current International
Class: |
A22C
17/04 (20060101); A22C 17/00 (20060101); B02C
019/22 (); B02C 023/16 () |
Field of
Search: |
;241/73,74,29,152A,82.1,185A,260.1,247,86,88,89.3 ;209/262,300,284
;17/46 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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200950 |
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Dec 1958 |
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30131 |
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Jun 1981 |
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EP |
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54866 |
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Dec 1889 |
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DE2 |
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2235045 |
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Jan 1974 |
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DE |
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2407293 |
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Aug 1974 |
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DE |
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1020046 |
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Nov 1952 |
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FR |
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1368221 |
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Jun 1964 |
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FR |
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1460403 |
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Nov 1966 |
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FR |
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341337 |
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Jan 1931 |
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GB |
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591554 |
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Aug 1947 |
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GB |
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717273 |
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Oct 1954 |
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GB |
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910127 |
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Nov 1962 |
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GB |
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1318742 |
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May 1973 |
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GB |
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Primary Examiner: Rosenbaum; Mark
Attorney, Agent or Firm: Rogers & Scott
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of my earlier
application Ser. No. 06/513,487 filed July 13,1983, now abandoned.
Claims
I claim:
1. Apparatus for the separation of a composite mixture of different
materials of different consistencies into separate fractions of the
different consistencies comprising:
an apparatus body having an apparatus inlet for the composite
mixture to be separated and respective outlets for the separated
fractions,
a rotary vaned pump having a pump compartment mounted by the said
body, the pump compartment having an inlet thereto receiving the
mixture from the apparatus inlet into the pump compartment and the
pump pressurising it in the pump compartment to an operative
separation pressure .Iadd.of at least 70 Kg/sq. cm. (1000
p.s.i.).Iaddend.,
said rotary vaned pump having a pump rotor carrying at least one
vane rotatable about a rotor axis, said one vane being mounted in a
respective radially-extending slot in the rotor and moving radially
therein as the rotor rotates, and defining at least two pump
chambers in the pump compartment, said pump chambers being formed
about a chamber longitudinal axis radially displaced from said
rotor axis so that each pump chamber decreases in volume as the
pump vane moves from the pump means inlet toward the pump means
outlet and increases in volume as the pump vane moves from the
outlet towards the inlet,
separator screen means mounted by the said body against a front
face of which the pressurised mixture is delivered for the
corresponding softer first fraction thereof to pass through the
screen to a rear face thereof and for the remaining second harder
fraction to be retained by the screen, and
means connecting at least the front face of the screen to a
respective outlet for the respective separated second harder
fraction,
said separator screen means and the outlet for the second harder
fraction maintaining the pressure of the pressurized mixture at
.[.an.]. .Iadd.said .Iaddend.operative separation pressure.
2. Apparatus as claimed in claim 1, wherein the said pump vane
extends on opposite sides of the pump rotor axis and is of fixed
radial length, and wherein the pump compartment has a curved
interior surface constituting an interior cam face for moving the
pump vane radially relative to the pump rotor as the rotor rotates,
said vane having its axial edges in operative contact with the said
interior cam face for radial movement thereby as the pump rotor
rotates.
3. Apparatus as claimed in claim 2, wherein the said separator
screen means comprises at least part of a circumferential wall of
the pump compartment providing the curved interior surface
constituting an interior pump cam face, wherein the said wall is
mounted for rotation about the axis of rotation of the rotor, and
there are provided means for rotating the wall about the said axis
for adjusting the timing of the pump cam.
4. Apparatus as claimed in claim 2, wherein the said separator
screen means comprises at least part of the circumferential wall of
the pump compartment providing the said circumferential interior
cam face.
5. Apparatus as claimed in claim 4, wherein the said
circumferential wall of the pump is mounted for rotation about the
axis of rotation of the rotor, and there are provided means for
rotating the wall about the said axis for adjusting the timing of
the pump cam.
6. Apparatus as claimed in claim 2, wherein the pump includes two
pump vanes mounted on the pump rotor transverse to one another,
both vanes being of fixed radial length and each pump vane
extending on both sides of the pump rotor longitudinal axis and
having both its radial edges in operative contact with the interior
cam face.
7. Apparatus as claimed in any one of claims 1, 2 or 6, wherein
shearing means is provided by the leading radial edge of each pump
vane, said leading radial edge being formed as a shearing knife
edge for shear cutting any shear-cuttable solid material passing
through the pump compartment inlet.
8. Apparatus as claimed in any one of claims 1, 2 or 6, wherein
shearing means is provided by the leading radial edge of each pump
vane, said leading radial edge being hollow ground to form a
shearing knife edge for shear cutting any shear-cuttable solid
material passing through the pump compartment inlet.
9. Apparatus as claimed in any one of claims 1, 2 or 6, wherein the
leading face of each pump vane leading edge that passes over an
inlet opening to the pump compartment is formed as a shearing knife
edge for shear cutting any shear-cuttable solid material entering
the pump compartment through the pump compartment inlet and engaged
by the shearing knife edge, and wherein an edge of the said pump
compartment inlet facing the said pump vane leading edge is formed
as a shearing edge and cooperates with the pump vane shearing knife
edge to shear cut solid material interposed between them as such
material passes through the opening.
10. Apparatus as claimed in any one of claims 1, 2 or 6, and
comprising:
a hopper for receiving the composite mixture to be separated, said
hopper having an outlet communicating with the inlet of the pump
compartment,
a conveyor screw rotatably mounted within the said hopper feeding
the mixture to the hopper outlet, and
means for rotating the conveyor screw.
11. Apparatus as claimed in any one of claims 1, 2 or 6,
comprising:
fraction separating means having at least a part of a wall thereof
constituted by the said separator screen means, which separator
screen means also constitutes the first outlet for said first
softer fraction;
the apparatus also comprising means connecting the interior of the
fraction separating means to the interior of the pump compartment
for delivering the pressurised mixture of material from the pump
compartment interior to the fraction separating means interior;
a conveyor screw rotatably mounted within the fraction separating
means for conveying the pressurised mixture towards the second
outlet therefrom for the second harder fraction, the softer
fraction being forced through the separator screen means as the
mixture is conveyed and the harder fraction exiting at said second
outlet; and
means for rotating the conveyor screw.
12. Apparatus as claimed in claim 11, wherein said conveyor screw
has substantial clearance between its exterior surface and the
cooperating interior surface of the fraction separating means.
13. Apparatus as claimed in any one of claims 1, 2 or 6,
comprising:
fraction separating means having at least a part of a wall thereof
constituted by the said separator screen means, which separator
screen means also constitutes the first outlet for said first
softer fraction;
the apparatus also comprising means connecting the interior of the
fraction separating means to the interior of the pump compartment
for delivering the pressurised mixture of material from the pump
compartment interior to the fraction separating means interior;
a conveyor screw rotatably mounted within the fraction separating
means for conveying the pressurised mixture towards the second
outlet therefrom for the second harder fraction, said softer
fraction being forced through the separator screen means as the
mixture is conveyed and the harder fraction exiting at said second
outlet;
means for rotating the conveyor screw, and
wherein the said separator screen means is provided with elongated
transverse angled slots through which the respective separated
softer fraction passes, the transverse angle of the slots
corresponding to the direction of movement of the material in the
fraction separating means by the conveyor screw.
14. Apparatus as claimed in any one of claims 1, 2 or 6, wherein
the said separator screen means comprises at least part of a wall
of the pump compartment.
15. Apparatus as claimed in any one of claims 1, 2 or 6,
comprising:
fraction separating means having at least a part of a wall thereof
constituted by the said separator screen means, which separator
screen means also constitutes the first outlet for said first
softer fraction;
the apparatus also comprising means connecting the interior of the
fraction separating means to the interior of the pump compartment
for delivering the pressurised mixture of material from the pump
compartment interior to the fraction separating means interior;
a conveyor screw rotatably mounted within the fraction separating
means for conveying the pressurised mixture towards the second
outlet therefrom for the second harder fraction, the softer
fraction being forced through the separator screen means as the
mixture is conveyed and the harder fraction exiting at said second
outlet;
means for rotating the conveyor screw; and
shearing .[.meads.]. .Iadd.means .Iaddend.before and in the
vicinity of said outlet of the fraction separation means to shear
to a smaller size the harder material of the harder fraction to
permit it to pass through said outlet.
16. Apparatus for separating materials of different consistencies
from a composite mixture thereof into separate fractions of
different consistencies comprising,
a rotary vaned pump having a pump compartment having an inlet for
receiving the composite mixture, and an outlet for expelling said
composite mixture, said pump being operable at a pressure .Iadd.of
from 70 Kg/sq. cm. (1000 p.s.i.) to 210 Kg/sq. cm. (3000 p.s.i.)
.Iaddend.sufficient to permit separation of the mixture into
separate fractions,
said pump having a pump rotor mounted in the pump compartment
carrying at least one vane rotatable about a rotor axis, said one
vane being mounted in a respective radially-extending slot in the
rotor and moving radially therein as the rotor rotates, and
defining at least two pump chambers, said pump chambers being
formed about a chamber longitudinal axis radially displaced from
said rotor axis so that each pump chamber formed by the pump vane
decreases in volume as the pump vane moves from the pump means
inlet toward the pump means outlet and increases in volume as the
pump vane moves from the outlet towards the inlet,
fraction separation means having an inlet for receiving said
pressurized composite mixture from the pump compartment outlet,
said fraction separation means having filter screen means for
separating a softer fraction from the mixture by passage of the
softer fraction therethrough and constituting a first outlet
therefrom and having second outlet means for discharging from the
fraction separation means a harder fraction retained by the filter
screen means,
conveyor means within said fraction separation means for conveying
said pressurized mixture from the inlet past said filter screen
means, said filter screen means and said separation means outlet
being proportioned such that a back pressure is created in said
pump means and in said separation means .Iadd.of from 70 Kg/sq. cm.
(1000 p.s.i.) and to 210 Kg/sq. cm. (3000 p.s.i.)
.Iaddend.sufficient to separate said softer fraction from the
harder fraction in said fraction separation means by forcing said
softer fraction through said filter screen means, and
shearing means before and in the vicinity of said outlet of the
fraction separation means to shear to a smaller size the harder
material of the harder fraction to permit it to pass through said
outlet.
17. Apparatus as claimed in claim 16, wherein the pump compartment
is bounded by two axially spaced parallel flat end surfaces
provided by respective pump end members having respective bearing
means for supporting the pump rotor for rotation, and a curved
tubular surface provided by an intermediate pump member between
said two flat surfaces, the curve of said tubular surface being
related to said pump compartment and rotor axis and defining a
non-circular surface which is contacted by both ends of the rotor
vane and which causes said rotor vane to move radially relative to
the rotor as the pump rotates.
18. Apparatus as claimed in claim 17, wherein, the intermediate
pump member providing the tubular surface is rotatable about the
rotor axis, to vary the space between the rotor and the pump
compartment outlet such that back pressure created in the
respective pump chamber is varied.
19. Apparatus as claimed in claim 17, wherein said pump compartment
inlet is provided in one flat end surface of the pump, said rotor
has two vanes mounted transverse to one another, and radial edges
of said vanes adjacent said inlet-provided flat surface are formed
as respective shearing knife edges for shearing shearable material
passing through said pump compartment inlet.
20. Apparatus for separating materials of different consistencies
from a composite mixture thereof into separate fractions of
different consistencies comprising:
a rotary vaned pump having an inlet for receiving said mixture to
be separated, and a pump compartment connected to the inlet to
receive composite mixture therefrom,
said pump having a pump rotor mounted in the pump compartment
carrying at least one vane rotatable about a rotor axis, said one
vane being mounted in a respective radially-extending slot in the
rotor and moving radially therein as the rotor rotates, and
defining at least two pump chambers, said pump chambers being
formed about a chamber longitudinal axis radially displaced from
said rotor axis so that each pump chamber formed by the pump vane
decreases in volume as the pump vane moves from the pump means
inlet toward the pump means outlet and increases in volume as the
pump vane moves from the outlet towards the inlet,
the pump compartment being bounded by two axially spaced parallel
flat end surfaces provided by respective pump end members having
respective bearing means for supporting the pump rotor for
rotation, and a curved tubular surface provided by an intermediate
pump member between said two flat surfaces, the curve of said
tubular surface being related to said pump compartment and rotor
axis and defining a non-circular surface which is contacted by both
ends of the rotor vane and which causes said rotor vane to move
radially relative to the rotor as the pump rotates,
shearing means at the pump inlet for shearing the portion of said
mixture entering the pump inlet and engaged by the shearing means,
said shearing means consisting of the opposite axial edges of the
vanes adjacent said tubular surface each formed a respective
shearing knife edge,
filter screen means formed by part of the said tubular surface
receiving composite mixture from the positive displacement pump
means for separating a fraction of a softer consistency from said
mixture,
outlet means downstream of said filter screen means for receiving a
fraction of a harder consistency separated from said structure,
said filter screen means and said outlet means being proportioned
to create a back pressure in said pump chamber .Iadd.at least 70
Kg/sq. cm. (1000 p.s.i.) .Iaddend.sufficient to cause separation of
said softer fraction from the harder fraction by passage of the
softer fraction through the filter screen means.
21. Apparatus for separating meat from bone comprising,
positive displacement pump means having a pump inlet for receiving
a mixture of meat and bone into the pump compartment, and a pump
outlet for expelling said composite mixture of meat and bone out of
the pump compartment, said positive displacement pump means
consisting of a rotary vaned pump having a pump rotor carrying at
least one vane rotatable about a rotor axis, said one vane being
mounted in a respective radially-extending slot in the rotor and
moving radially therein as the rotor rotates, and defining at least
two pump chambers in the pump compartment, said pump chambers being
formed about a chamber longitudinal axis radially displaced from
said rotor axis so that each pump chamber decreases in volume as
the pump vane moves from the pump means inlet toward the pump means
outlet and increases in volume as the pump vane moves from the
outlet towards the inlet,
separation means having a separation means inlet for receiving
pressurized meat/bone mixture from the pump outlet which is at a
pressure .Iadd.of at least 70 Kg/sq. cm. (1000 p.s.i.) and
.Iaddend.sufficient to permit separation of the meat and the bone,
said separation means having filter screen means for separating the
meat from the bone and outlet means for discharging the separated
bone,
conveyor means within said separation means for conveying said
pressurized mixture from the inlet of the separation means past
said filter screen means, said conveyor means consisting of a screw
conveyor mounted within said separation means and having
substantial clearance between its exterior surface and the
cooperating interior surface of the filter screen means, said
filter screen means and said separation means outlet being
proportioned such that a back pressure is created in said pump
means and in said separation means .Iadd.of at least 70 Kg/sq. cm.
(1000 p.s.i.) and .Iaddend.sufficient to separate meat from bone by
forcing said meat through said filter screen means.
22. Apparatus as claimed in claim 21 including:
a hopper for receiving the mixture to be separated, said hopper
having an outlet communicating with the inlet of the positive
displacement pump means,
a conveyor screw rotatably mounted within the said hopper feeding
the mixture to the hopper outlet, and
means for rotating the hopper conveyor screw.
23. Apparatus as claimed in claim 21, wherein said positive
displacement pump means including shearing means for shearing any
shearable material passing through said pump inlet and engaged by
the shearing means to a preselected size, said shearing means
consisting of edges of the pump vane that pass over the pump
compartment inlet.
24. Apparatus as claimed in claim 21, and including shearing means
before and in the vicinity of said outlet of the separation means
to shear to a smaller size bone of said preselected size for
passing through said separation means outlet.
25. Apparatus for separating fractions of different consistencies
from a composite mixture thereof comprising:
positive displacement pump means constituted by a rotary vaned pump
having a pump inlet for receiving said mixture, said pump including
shearing means for shearing shearable material in said mixture
passing through the pump inlet and engaged by the shearing means to
a preselected size, the pump having a first pump outlet for
discharging a first fraction of softer consistency from the
mixture, and a second pump outlet for discharging a second fraction
of harder consistency from the mixture,
said pump having an interior pump chamber defined by two axially
spaced parallel flat end surfaces provided by respective pump end
members having respective bearing means for supporting the pump
rotor for rotation, and a curved tubular surface provided by an
intermediate pump member between said two flat surfaces, the rotor
including vanes adapted to be moved by engagement with said curved
tubular surface as the rotor rotates, the curve of said tubular
surface being related to said pump compartment and rotor axis and
defining a non-circular surface which is contacted by both ends of
the rotor vane and which causes said rotor vane to move radially
relative to the rotor as the pump rotates, and
filter screen means for separating the softer first fraction from
the harder second fraction by passage of the softer first fraction
therethrough, said filter screen means forming part of the interior
curved tubular surface of the pump compartment and constituting the
said first pump outlet,
said rotor means constituting means effective to positively convey
said mixture from the pump inlet past the filter screen means to
the second pump outlet, the second pump outlet and the filter
screen means together producing a back pressure .Iadd.of at least
70 Kg/sq. cm. (1000 p.s.i.) and .Iaddend.in the pump chamber
sufficient to force the softer fraction through the filter screen
means as the rotor means rotate to convey the mixture past the
filter screen means,
said harder fraction being passed by the rotor means to the second
pump outlet.
26. Apparatus as claimed in claim 25, wherein the pump vane leading
edges that pass over the pump inlet are hollow ground to form said
shearing means.
27. Apparatus as claimed in claim 26, wherein an edge of the said
pump inlet facing the pump vane leading edges formed as respective
knife edges is formed as a shearing edge and cooperates with the
pump vane shearing knife edges to shear hard material as it passes
through the pump inlet. .Iadd.
28. Apparatus as claimed in claim 20, wherein the rotary vaned pump
is operable at a pressure of from 70 Kg/sq. cm. (1000 p.s.i.) to
210 Kg/sq. cm. (3000 p.s.i.), and the back pressure created in the
pump and the separation means is from 70 Kg/sq. cm. (1000 p.s.i.)
to 210 Kg/sq. cm. (3000 p.s.i.). .Iaddend. .Iadd.29. Apparatus as
claimed in any one of claims 21, 22 or, 23, wherein the rotary
vaned pump is operable at a pressure of from 70 Kg/sq. cm. (1000
p.s.i.) to 210 Kg/sq. cm. (3000 p.s.i.), and the back pressure
created in the pump and the separation means is from 70 Kg/sq. cm.
(1000 p.s.i.) to 210 Kg/sq. cm. (3000 p.s.i.). .Iaddend. .Iadd.30.
Apparatus as claimed in any one of claims 25, 26 or 27, wherein the
rotary vaned pump is operable at a pressure of from 70 Kg/sq. cm.
(1000 p.s.i.) to 210 Kg/sq. cm. (3000 p.s.i.), and the back
pressure created in the pump and the separation means is from 70
Kg/sq. cm. (1000 p.s.i.) to 210 Kg/sq. cm. (3000 p.s.i.). .Iaddend.
.Iadd.31. Apparatus as claimed in any one of claims 1, 2 or 6
comprising:
fraction separating means having at least a part of a wall thereof
constituted by the said separator screen means, which separator
means also constitutes the first outlet for said first softer
fraction;
the apparatus also comprising means connecting the interior of the
fraction separating means to the interior of the pump compartment
for delivering the pressurised mixture of material from the pump
compartment interior to the fraction separating means interior;
a conveyor screw rotatably mounted within the fraction separating
means for conveying the pressurised mixture towards the second
outlet therefrom for the second harder fraction, the softer
fraction being forced through the separator screen means as the
mixture is conveyed and the harder fraction exiting at said second
outlet;
the pump rotor and the conveyor screw being coaxial with one
another and connected together for rotation together; and
the apparatus comprising means for rotating the pump rotor and
thereby rotating the conveyor screw. .Iaddend. .Iadd.32. Apparatus
as claimed in claim 21, wherein said pump rotor and said screw
conveyor are coaxial with one another and are connected together
for rotation together, so that rotation of the pump rotor produces
rotation of the screw conveyor. .Iaddend. .Iadd.33. Apparatus as
claimed in claim 22, wherein said pump rotor, said screw conveyor,
and said conveyor screw are coaxial with one another and connected
together for rotation together, so that rotation of the conveyor
screw produces rotation of the pump rotor and the screw conveyor.
.Iaddend.
Description
FIELD OF THE INVENTION
The present invention is concerned with apparatus for the
separation of mechanical mixtures of materials of different
consistencies, such as a mixture of meat and bone, or a mixture of
water and solid material such as sewage.
REVIEW OF THE PRIOR ART
Processes and apparatus for the separation of mixtures of materials
of different consistencies into component parts are employed in
many different industries. For example, in sewage treatment it is
necessary at some stage to separate as much as possible of the
liquid components of the sewage from the various more solid
components, so that they can be subjected separately to appropriate
treatments. The presence of the solid components causes
considerable difficulty in the handling of the mixtures prior to
their separation.
The mechanical separation of mixtures of meat and bone into
separate components is now a well-established industry. Although
usually the machines were proposed for use with different animal
and fish species, in practice the earlier machines were operable
most successfully with chicken parts, where the difference in
consistencies between the meat and the bone is adequate, but the
bones are not too difficult to break without splintering and
powdering. Attempts to use the machines with other meats, such as
beef, pork and fish, were not as successful. Even with chicken,
problems were and still are encountered when attempting to obtain
maximum production from a machine, such as too much bone content in
the meat fraction, beyond the limits permitted by the licensing
authorities, or too great a temperature increase in the meat
fraction during separation, resulting in lowering in quality and
texture of the separated meat. A separating apparatus that proved
particularly commercially successful is described in U.S. Pat. Nos.
4,025,001 and 4,069,980, issued respectively May 24, 1977 and Jan.
24, 1978, while a subsequent machine is described in U.S. Pat. No.
4,340,184, issued July 20, 1982.
.Iadd.There is disclosed in U.K. patent specification No. 1,318,742
published May 31, 1973, of Beehive Machinery Inc. a process and
apparatus for producing de-boned meat products. FIGS. 11-14 thereof
disclose one such apparatus wherein a slurry of meat or fish
material ground in standard equipment, e.g. a high pressure
extrusion type grinder, is run into a hopper equipped with double
mixing screws to keep the solids in suspension. The lower screw
feeds the slurry into the intake end of any suitable pump for
example a rotary vane pet food pump marketed by Autio Equipment
Company, Astoria, Oreg., having its working parts specially
hardened against bone abrasiveness. A conduit conducts the pump
discharge into the free end of a de-boning conduit under a pressure
that may vary between about 5 to 250 lbs/sq. in., depending upon
the volume and the character of feed and the speed of rotation of
the conveyor compression screw. .Iaddend.
DEFINITION OF THE INVENTION
It is the principal object of the invention to provide a new
apparatus for the separation of mixtures of materials of different
consistencies, such as mixtures of meat and bone.
In accordance with the present invention there is provided
apparatus for the separation of mixtures of materials of different
consistencies into separate fractions thereof comprising:
an apparatus body having an inlet for the mixture to be separated
and respective outlets for the separated fractions, positive
displacement pump means constituted by a rotary vaned pump having a
pump chamber mounted by the said body receiving the mixture from
the inlet into the pump chamber and pressurising it in the pump
chamber to an operative separation pressure .Iadd.at least 70
Kg/sq. cm. (1000 p.s.i.).Iaddend.,
separator screen means mounted by the said body against a front
face of which the pressurised mixture is delivered for the
corresponding first fraction thereof to pass through the screen to
a rear face thereof and for the remaining second fraction to be
retained by the screen, and
means connecting at least one of the front and rear faces of the
screen to the respective outlet for the respective separated
fractions.Iadd., said separator screen means and the outlet for the
second harder fraction maintaining the pressure of the pressurized
mixture at said operative separation pressure.Iaddend..
DESCRIPTION OF THE DRAWINGS
Separators which are particular preferred embodiments of the
invention will now be described, by way of example, with reference
to the accompanying diagrammatic drawings, wherein:
FIG. 1 is a longitudinal cross-section through a first embodiment,
in which a positive displacement pump feeds the mixture to be
separated to a separate, attached separating unit;
FIG. 2 is a similar cross-section, to a larger scale, through the
positive displacement pump of the separator of FIG. 1, in order to
show the construction thereof, taken on the line 2--2 in FIG.
3;
FIG. 3 is a plane cross-section taken on the line 3--3 in FIG.
2;
FIG. 3A is a plane cross-section of a detail of a vane of the pump
of FIGS. 2 and 3, taken on the line 3A--3A of FIG. 3;
FIG. 4 is a longitudinal cross-section through a second embodiment,
in which the separating unit is an integral part of the positive
displacement pump, the section being taken on the line 4--4 in FIG.
5;
FIG. 5 is a transverse cross-section of the embodiment of FIG. 4,
taken on the line 5--5 in FIG. 4;
FIG. 6 is a longitudinal cross-section through a third embodiment,
again in which the separating unit is an integral part of the
positive displacement pump, the section being taken on the line
6--6 in FIG. 7;
FIG. 7 is a transverse cross-section taken on the line 7--7 in FIG.
6;
FIG. 8 is a front elevation of a separator element for use in the
embodiments of FIGS. 4 through 7;
FIGS. 9 and 10 are respective side elevations of two different
groups of separator elements for use in the embodiments of FIGS. 4
through 7;
FIGS. 11 and 12 are respective front elevations of portions of a
unitary separator element for use in the embodiments of FIGS. 4
through 7;
FIG. 13 is an outline diagram of the internal cam face of the
positive displacement pump in side elevation and a rotor blade to
accompany a description of a manner of calculating the cam face
profile to permit its manufacture.
FIG. 14 is a longitudinal cross-section similar to FIG. 1 through a
fourth embodiment; and
FIGS. 15 and 16 are perspective views respectively of two further
forms of separator element for use in the embodiments of FIGS. 1
and 14.
The same references will be used if possible for similar parts in
all the figures of the drawings.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The apparatus of FIGS. 1 through 3A is intended principally for the
mechanical separation of various kinds of meats from the bones to
which they are attached. A substantial industry has developed,
based on the use of such machines, since they are able economically
to remove a substantial proportion of edible meat from fowl, animal
and fish parts that would otherwise be discarded for food purposes,
such as the necks and backs of chickens that have been cut in
pieces for separate sale of the legs, breasts and wings. In
practice the separation cannot be complete and the separated bone
fraction will still contain some meat, while the separated meat
fraction will also contain a small amount of bone in the form of
tiny particles thereof. Food licensing authorities have instituted
strict regulations as to the maximum overall percentage of bone and
maximum particle size of the bone that is permitted in the
resultant meat products. For example, the regulations of the U.S.
Food and Drug Administration permit a maximum bone content of 2% by
weight and a maximum bone particle size of 0.5 mm. These standards
are difficult to achieve.
The apparatus consists of a frame 10 providing a hopper 12 into
which the meat and bone mixture to be separated is delivered. The
hopper contains a longitudinal conveyor screw 14 rotated about a
horizontal axis by a drive rotor (not shown) via a connecting drive
gear 16 and a splined drive output shaft 18 mounted in a bearing 20
in an end plate of the frame. Special bearing seals such as 22 are
required, as is well known to those skilled in the art of food
handling machinery construction, to prevent entry to the bearings
of the body fluids that accompany meats.
The hopper body is provided with a front end flange 24 to which is
fastened the adjacent rear end mounting flange 26 of a rotary,
radial-vane, positive-displacement pump indicated generally by the
reference 28. Referring now especially to FIGS. 2, 3 and 3A, the
pump comprises a cylindrical housing 30 having the rear mounting
flange 26 at one end and a comparable front mounting flange 32 at
the other end. Front and rear bearing plates 34 and 36 respectively
are mounted in the cylindrical housing on either side of a hollow
cam plate 38, so that the plates 34, 36 and 38 form a pump chamber
between them. The pump rotor is provided with two cylindrical plain
bearing portions 40 and 42 that are mounted in respective bores in
the bearing plates to support the rotor for rotation about a
horizontal axis coaxial with the axis of rotation of the hopper
conveyor screw 14. Both ends of the pump rotor protrude from the
respective bearing plates and are splined, the rear rotor end 44
engaging in the adjacent end of the conveyor screw 14 to be driven
thereby, while the front rotor end 46 engages in the rear end of
another conveyor screw to be described below. The assembly of end
plates, cam plate and rotor is retained in the housing by a
retainer ring 48 screw-threaded into the front end of the housing
30.
A circumferentially elongated axial inlet 50 to the pump chamber is
provided in the rear end plate 36 and a circumferentially elongated
axial outlet 52 is provided in the front end plate 34, the two
openings being disposed diametrically opposed from one another
about the axis of rotation of the rotor. The pump has two
radially-extending pump vanes or blades 54a and 54b each sliding
radially in a respective radial slot in the rotor boss 56, the two
slots and therefore the two blades being disposed at right angles
to one another. Both blades are of an axial width to fit without
appreciable play between the two facing axial faces of the end
bearing plates, and they are both provided with mating
complementary half-width radially elongated slots 58a and 58b
respectively to permit the required radial sliding movements in the
rotor boss as it rotates about the axis 58. The tips 60 of the
blades engage an internal cam constituted by the inside surface 62
of the bore in the hollow cam plate 38, the tips being rounded to
facilitate the rubbing contact as they move over the surface. The
surface 62 is generated so that at all times during the rotation of
the pump rotor the blade tips are in contact with it, so that the
contents of the pump chamber are positively displaced through the
pump from the inlet to the outlet, and relatively high pump
pressures, e.g. usually from 70-210 Kg/sq. cm (1000-3000 p.s.i.),
can readily be generated. The manner in which such a cam surface is
determined is described below.
The leading edges of the pump blades adjacent to the rear bearing
plate 36 are hollow ground at 64 (FIG. 3A) and hardened to form
cutting edges 66. The trailing edge of the inlet 50 is also
provided at 68 with a shearing edge that will cooperate with the
vane cutting edges 66 to shear any hard material, such as a piece
of bone, that protrudes through the inlet 40 into the pump chamber.
The bone pieces are moved by the respective blade through the pump
chamber and out through the outlet 52. If the bone piece jams in
the outlet it will be shared against the outlet trailing edge 68 by
the following blade, the sheared off piece being carried around
until it can be expelled at a subsequent passage of the blade over
the outlet.
The mixture of meat and bone pieces is fed from the outlet 52 into
a separator chamber indicated generally by the reference 70 (FIG.
1). In this embodiment this chamber is constituted by a rear end
plate 72 that is secured to the pump front end plate 34 by a
circumferential clamp ring 74. The separator chamber provides a
cylindrical separator or filter constituted by a large plurality of
annular separator plates 76 that are tightly clamped together
between the rear end plate 72 and a front end plate 78 by a number
of heavy axial circumferentially-spaced tie bolts 80. The separator
plates are held aligned with one another to provide a smooth
internal cylindrical front face 81 by axial aligning bars 82
engaged in radial slots in the plates. The chamber encloses an
elongated feed screw 84 mounted by splined front rotor end 46 and a
bearing 86 for rotation about an axis coaxial with the pump axis
58, and driven in such rotation by the rotor end 46. Rotation of
the screw 84 conveys the pump-pressurised mixture of meat and bone
along the interior of the cylindrical separation chamber 70, the
pressure being such that the softer meat tissue is squeezed through
the filter 76 to the outside rear separator surface, the filter
thus constituting in this embodiment the meat fraction outlet, from
which it will fall into a suitable collector receptacle (not
shown), while the bone and unseparated meat eventually exit from an
annular bone fraction outlet 88 to another respective collector
receptacle (also not shown). As is known to these experienced in
this art the flow capacity of the filter 76 and of the annular bone
friction outlet must be such that there is sufficient back pressure
created, whereby the operative pressure in the separation chamber
provided by the pump is maintained within the require range for the
mixture undergoing separation. The flow capacity of a specific
filter is not easily changed, and it is more usual to change the
filter completely; the bone outlet may be of fixed or variable flow
capacity. For more details of the construction and operation of
this type of separator unit reference may be made to the above
mentioned prior U.S. Pat. Nos. 4,025,001; 4,069,980 and 4,340,184,
the disclosures of which are incorporated herein by this
reference.
The screw 84 is provided next to its discharge end with a portion
130 of reduced diameter provided with moving lands 132 cooperating
with stationary lands 134 provided on a topical frusto-conical
internal face of a machine part 136. These lands cooperate to form
a bone breaker that will break only large pieces if bone in the
existing material to ensure that they will not jam the outlet
88.
In the above-described prior apparatus the hopper and separator
feed screws, corresponding to the two screws 14 and 84 herein,
cooperate to pressurise the mixture of meat and bone to the
pressure values mentioned above, which currently are necessary to
obtain satisfactory separation without more than the permitted
amount of bone being discharged in the softer meat tissue fraction.
In the apparatus of the invention this necessary pressurisation is
performed predominantly, and in some embodiments solely, by the
positive displacement pump 28. The conveyor screws inherently will
add a small amount to the pressurisation, but this will not be
significant compared to that provided by the pump.
Since the hopper and separator feed screws 14 and 84 are now
relieved of the task of pressurising the mixture their design
becomes much less onerous and critical. The use of the positive
displacement pump, which also acts to break the bones cleanly to
suitable size, permits close control of the pressure produced with
greatly reduced dependence upon the nature of the mixture and the
relative porportions of bone and meat that are present. In the
prior art apparatus as represented by those described in the
above-mentioned U.S. patents, the screw conveyors had the dual
function of pressurising the mixture and also conveying it through
the apparatus, and the pressures which the two screws, particularly
the separator screw, were able to apply to the mixture depended in
a complicated manner on the relative friction between the meat/bone
mixture, the screw body and the front face of the separator, and
the maximum shear to which the meat or bone could be subjected. The
friction also of course differed for different types of meat, and
also differed among meats of the same type, depending for example
on the proportion of fat present. An optimum condition for good
separation is a relatively steady high pressure, but high pressures
are difficult to achieve with single screw conveyors. Higher
pressures can be obtained with twin screw conveyors, but these are
difficult and expensive to design, manufacture and maintain.
Attempts to increase the pressure simply by increasing the speed of
rotation can easily lead to a situation in which the screw conveyor
is shearing the meat without increasing the pressure, resulting in
excessive temperature rise and degradation of the quality and
texture of the meat fraction.
In the apparatus of the invention the positive displacement pump
pressurises the mixture without any substantial shearing, except
minor amounts at the entry and exit openings, and the conveyors
need only convey the material without pressurisation. The screw
conveyor 84 must be of smaller volume between successive lands
along its length toward the bone fraction exit 88 to take account
of the decrease of product volume radially through the filter. Some
adjustment of rotational speed may be desirable to take account of
different proportions of meat and bone. Thus, if the proportion of
bone is high it would be desirable, through not essential, to
employ a higher rotational speed of the conveyor 84 in order to
expel the larger quantity of bone and maintain the output of the
apparatus as high as possible.
FIGS. 4 and 5 illustrate a second embodiment in which the positive
displacement pump 28 has an axial inlet as with the pump of the
apparatus of FIGS. 1 to 3, but has two radial outlets from the pump
chamber in the circumferential wall thereof, one of which is
constituted by circumferential filter element segments 76 through
which the separated meat fraction is expressed to a corresponding
outlet 90 from the casing 30, and the other of which is the outlet
88 for the bone fraction. This embodiment therefore provides an
exceptionally compact form of the apparatus. The apparatus is also
suited to any other application in which at least some separation
is required from a mixture into two components of different
consistencies, for example some dewatering of a sludgy
material.
In this embodiment the hollow cam plate 38 has an arc of its wall
constituted by the separator elements 76 and is mounted in an
annular support member 92, which is in turn rotatably mounted in
the housing 30 for rotation about the axis of rotation of the
rotor. The cam plate can therefore be rotated relative to the rotor
to adjust the timing of the cam and the location of the outlet 88
relative to the point of minimum volume of the chamber 70 defined
by the cam, so as to take account of differences in the relative
volumes of the two fractions to be produced by the apparatus. In
this embodiment the rotation of the cam plate is effected by a
shaft 94 mounted in a bore 96 of the housing for longitudinal
movement under the control of a linear operating rotor device (not
shown) such as a hydraulic piston and cylinder motor. The shaft 94
is provided at 98 with rack teeth which mesh with cooperating rack
teeth that extend over a sector 100 of the outer periphery of the
support member 92. The outlets 88 and 90 in the casing 30 for the
two separated fractions are of greater circumferential extent than
the corresponding outlets 52 and separator 76 to be able to
accommodate this rotation of the cam plate.
Since the apparatus is not required to drive any other piece of
apparatus the end plate 34 provides an annular bearing for the
adjacent rotor end and is secured to the casing 30 by quick release
bolts 104. At the other side the apparatus is provided with an end
closure plate 106 bolted to the casing 30 and supporting a thrust
bearing 108. The support member 92 completely encloses the cam
plate 38 and in so doing also serves to retain in position the
separator elements 76 against the relatively high radially
outwardly acting pressure of the material passing through it.
The embodiment of FIGS. 6 and 7 is functionally similar to that of
FIGS. 4 and 5, the essential difference being that the inlet 50 to
the pump chamber and the associated inlet 110 to the casing 30 are
both radial. The hollow ground portions and associated shearing
knife edges must therefore be provided at the tips of the vane
blades.
FIG. 8 shows in greater detail a structure for the arcuate
separator element 76 as employed in the embodiments of FIGS. 4
through 7, as seen in side elevation, while FIGS. 9 and 10 show
different forms of element in end elevation. With the form of
element illustrated by FIGS. 8 and 9, each element comprises a
central web 112 that remains from the removal of material from a
thick plate to leave a narrow arcuate radially-inner portion 114.
This portion 114 is provided with radial slots 116 through which
the separated softer component flows, while the harder component is
moved by the vane blades over the separator inner surface 81, which
in this embodiment, at this part of the chamber, also constitutes
part of the cam surface 62. A plurality of such elements are
assembled together and tightly packed with plain flat spacing
elements 118 between each two adjacent elements.
In the embodiment illustrated by FIGS. 8 and 10 together the
portion 114 is left at one side only of the element and the slots
116 are formed in this one side, so that the elements can be packed
tightly together without the need for intermediate plain flat
elements. FIGS. 11 and 12 show unitary filter structures 120 that
can be used in place of the stack of elements consisting of a
suitably fashioned sheet provided with a large plurality of round
holes 112 (FIG. 11) or slots 124 (FIG. 2) elongated in the
direction of movement of the rotor blades.
FIG. 13 is an outline diagram of the internal cam face 62 of the
cam plate 38 and illustrates one manner of calculating the
necessary cam face profile. The figure shows diagrammatically the
side elevation of the cam face 62 and a single vane 54a stopped in
one position. The diagram shows the centre line .cent..sub.1 of the
rotor having its centre of rotation at 126, and the centre line
.cent..sub.2 of the cam having its centre of rotation at 128. The
distance between the two centres is the eccentricity E which is
known. The blade length L and thickness W are also known. The
centre line of the blades must always pass through the centre 126
while the eccentricity E is directly proportional to the volume
output of the pump and locates the imaginary centre 128 of the cam.
The rotor blades must seal the spaces between the rotor blades at
all times, and therefore must at all times and in all positions of
the rotor be in touch with the cam at both ends.
It is arbitrarily chosen that the maximum arc shall be of constant
radius R, and this is the arc ACB centered at 128 with chord equal
to the blade length L. Some correction must be made to L to account
for the thickness of the blade and for the rounded tips of radius
W/2. The variable cam radius r measured from centre 128 will vary
with the angle 0 and can be calculated geometrically, but an exact
equation solution is not easily attainable. The problem is
particularly suited to an iterative approach, especially with the
use of a computer to effect the relatively large number of
calculations required to obtain the values of the cam radius
necessary for the required accuracy of manufacture.
A value known to be a practical value is assumed for the angle
between the blade centre line and a radius through the centre 128.
Angle .beta. can then be determined for any subsequent value of
knowing that the sum of angles +.beta.+O must be 90 degrees. The
values of variable cam radius r can then be calculated from the
relationships ##EQU1## both of which must be satisfied. If the
agreement is not within the required tolerance must be adjusted and
the procedure repeated until it is. All of the points on the
non-constant radius arc ADB can be calculated using the different
values of O involved.
Other forms of rotary vaned pumps may also be employed in which the
vanes are of fixed length, for example a pump of the type in which
the vanes are mounted in radial slots in the rotor with their
parallel largest faces parallel to the axis of rotation; the two
radially-extending edges of each vane engage complementary face
cams on the two facing end walls and, as the rotor rotates, cause
the vanes to slide axially of the rotor in their radial slots to
vary cyclically the volumes of the chambers formed between the
rotor and the end wall face cams. The shearing knife edge will, as
with the previously-described embodiments, be provided at the edges
which traverse the inlet aperture. However, such a structure
requires the accurate production of two complementary face cams and
their subsequent assembly facing one another and spaced accurately
apart, so that the resulting construction is substantially more
expensive than those described above.
Another embodiment of the invention is illustrated by FIG. 14,
which is similar to the embodiment of FIGS. 1-3. Since, as
explained above, the screw 84 is no longer required to pressurise
the mixture in the chamber 70, it can be made somewhat shorter in
length and substantial clearances can be provided between its
exterior surface and 10 the interior surface of the separator
elements 76. In this embodiment the screw is designed and arranged
to apply a pulsating radially-outwardly-acting force to the mixture
which will facilitate the passage of the meat component through the
separator screen, and hence the separation. To this end the screw
profile is formed to be radially eccentric about the longitudinal
axis of rotation. The screw tapers outwardly from the pump outlet
52 to the separator outlet 88 in order to take account of the
progressive reduction in the volume of the mixture, but the screw
lands are much reduced in radial extent as compared with the
embodiment illustrated by FIG. 1, where the screw lands just clear
the interior walls of the separator elements 76. In this embodiment
the screw portion 130 is provided with moving bone-breaking means
132 which cooperate with a smooth frusto-conical wall of the
machine paid 136 to perform there bone-breaking function.
This large spacing between the land tips and the separator screen
reduces the possibility of pieces of the harder component being
forced through the screen slots or jammed in the slots. In a
specific example of an apparatus in which the diameter of the
chamber 70 is 15 cm (6 in.) the clearance between the tips of the
vestigial lands and the cylindrical interior wall can be as much as
9.5-19 mm (0.375-0.75 in.), the spacing of course varying as the
screw rotates because of the eccentricity. In this embodiment the
outlet 88 for the harder fraction is radial from the chamber
70.
The separator means described in relation to FIGS. 1-10, 12 and 14
provide circumferentially extending elongated slots through which
the softer fraction (the meat fraction) is expressed. The mixture
is moved within the chamber 70 both longitudinally and
circumferentially thereof, so that the mixture is moved across the
slots with a certain degree of shearing action. Round apertures 122
as employed in the embodiment of FIG. 11 are multi-directional, but
the size of hole that can be used is severely limited by the
requirement as to the size of solid particles that can be present
in the softer fraction. It is therefore preferred to use elongated
slots which are both easier to form by cutting or milling and also
provide for greater through-put of the apparatus. With some
embodiments therefore it may be preferred to use a separator
element 76 as illustrated by FIG. 15, which is cylindrical and is
provided with longitudinally-extending slots 124; a number of such
elements will be assembled end to end and held in place via bars
82.
Such a cylindrical separator element 76 may also take the form
illustrated by FIG. 16, in which elongated slots 124 are disposed
at a transverse angle such that they extend both longitudinally and
transversely, the angle being determined to match as closely as
possible the actual direction of movement of the material in the
chamber 70 and minimize shearing between the mixture and the long
slot edges. Minimum shearing is desired, especially in apparatus
for the separation of meat and bone, since excessive shear can have
a deleterious effect upon the quality of the separated softer
material. It will be understood that different transverse angles
will be optimum for different mixtures to be separated.
* * * * *