Note: Descriptions are shown in the official language in which they were submitted.
Background of the Invention
1. Field of the Invention.
This invention pertains generally to apparatus
for rendering fat from animal material.
2. Description of the Prior Art.
A conventional apparatus for the continuous ren-
dering of fat from animal material utilizes a series of
heated, vertically spaced and interconnected horizontal
cylinders or tubes for the sequential flow therethrough
of material to be rendered. One such apparatus is dis-
closed in U.S. Patent 3,410,882 granted November 12, 1968.
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However, no provision is shown therein for rendering
under vacuum conditions. Inasmuch as substantial water
vapor in the form of product steam is developed, the
continuous removal thereof, aided by the vacuum, during
the process is most desirable. Further, the vacuum pre-
vents the oxidizing of the product fat because of the air-
free environment. U.S. Patent 3,782,902 granted January
1, 1974, and assigned to assignee of sub~ect application
discloses an apparatus to accomplish this result. The
standpipe arrangement disclosed in this patent preserves
the vacuum condition in the apparatus.
While the above-noted apparatus shown in U.S. Patent
3,702,902 has proved to be relatively efficlent, neverthe-
less the output of the apparatus could be improved.
Because of the size of each tube, which may be 24 inches
O.D. and the need to provide for the mounting of the
agitator shaft on the ends thereof, the inlet and dis-
charge were made through the tube wall. Of necessity,
this restricted the length of the steam ~acket to a dimen-
sion short of the full length of the tube. Also the
agitator member had to have a length short of the full
length of the tube to avoid interference with the dis-
charge and to allow provision for a gateor dam to control
material flow through the tube. Further, venting of the
product steam was also provided through the tube wall and
preferably at the discharge end. As a consequence of the
above construction, the capacity of each tube in rendering
or cooking output and evaporation rate is unduly low.
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Summary of the Invention
lhe present invention provides a continuous rendering apparatus of
the type comprising: a plurality of generally horizontal cylinders having
opposed end walls and arranged one above the other, connection means inter-
coupling the discharge end of each cylinder and the entry end of the cylinder
therebeneath, the discharge end of each cylinder being adjacent the entry end
of the cylinder therebeneath, whereby the material to be rendered passes
sequentially and downwardly through said cylinders, heating means for heating
each cylinder, elongated agitator means rotatably positioned in each cylinder
for moving the material about the inner circumference of each cylinder, vent
means from each cylinder for venting the vaporized moisture, vacuum means
connected to each of said vent means for creating a vacuum in each of said
cylinders, and seal means connected to a discharge pipe of the lowest cylinder
; for preserving the vacuum in said cylinders, wherein the improvement com-
prises: said connection means including a discharge opening in the exit end
wall of each cylinder, an inlet opening in the entry end wall of the cylinder
therebeneath, and a discharge chute for each discharge opening, each chute
extending beyond the ends of said cylinders and intercoupling a respective
discharge opening with the inlet opening therebelow; said discharge opening
being generally L-shaped and having a curved surface extending only along a
portion of the lower half of the cylinder and generally aligned with the
inner periphery thereof and said opening extending over only a portion of the
lower half of said cylinder with its highest point being on said curved
surface in the direction of rotation of said agitator means.
The present invention also provides a continuous rendering apparatus
of the type comprising: a plurality of generally horizontal cylinders having
opposed end walls and arranged one above the other, connection means inter-
coupling the discharge end of each cylinder and the entry end of the cylinder
therebeneath, the discharge end of each cylinder being adjacent the entry end
of the cylinder therebeneath, whereby the material to be rendered passes
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sequentially and downwardly through said cylinders, heating means for heating
each cylinder, elongated agitator means rotatably positioned in each cylinder
for moving the material about the inner circumference of each cylinder, vent
means from each cylinder for venting the vaporized moisture, vacuum means
connected to each of said vent means for creating a vacuum in each of said
cylinders, and seal means connected to a discharge pipe of the lowest cylinder
for preserving the vacuum in said cylinders, wherein the improvement com- -
prises: said connection means including a discharge opening in the exit end
wall of each cylinder, an inlet opening in the entry end wall of the cylinder
1~ therebeneath, and a discharge chute for each discharge opening, each chute
extending beyond the ends of said cylinders and intercoupling a respective
discharge opening with the inlet opening therebelow; said discharge opening
having a curved surface extending only along a portion of the lower half of
the cylinder and generally aligned with the inner periphery thereof and said
opening extending over only a portion of the lower half of said cylinder with
its highest point being on said curved surface in the direction of rotation
of said agitator means; said opening being generally L-shaped with a generally
vertical leg and a generally horizontal leg, said generally vertical leg
extending upwardly along said curved surface to a point approximately on the
horizontal diameter of said cylinder, said generally horizontal leg extending
from the bottom of said vertical leg away from said curved surface a distance
less than the full diameter of said cylinder.
Generally, the Applicant provides an apparatus that doubles the
rendering output and evaporation rate without a similar increase in size.
Specifically, for example, Applicant increased each tube size from 24 inches
O.D. to 36 inches O.D. for a five tube apparatus compared to a 6 tube apparatus
of similar length, thus providing only 53% greater area. Further, and more
importantly, for example, Applicant relocated the material inlet and dis-
charge of each chamber or tube to the ends thereof and also the product steam
vents along with the agitator bearings. According to the present invention
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the steam jacket can extend the full length of the tube along with the
agitator member. Hence, the heat transfer to the material is substantially
improved since the entire length of tube is now utilized.
Also important in achieving the noted capacity is a consideration
of the agitator operation. In apparatus of this type, the material moves
sequentially through the tubes generally propelled by the incoming material
and gravity. However, some longitudinal impetus is given to the material
by the later to be described agitator. The agitator includes a shaft
extending longitudinally through the tube and has a plurality of paddle-
like elements thereon that extend toward the inner circumference of the tube.
Preferably the agitator is rotated at sufficient speed, which may be
approximately 50 RPM, for the apparatus detailed to cause the material, which
may cover the lower quarter of the tube at rest, to be thrown outwardly
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by centrifugal force against the inner circumference of
the tube and move around same in a spiral fashion to a
discharge. Speeds of 72 and 88 RPM have also proven to
be satisfactory. Besides providing a good heat transfer
rate to the material, this clears a large portion of the
tube for product steam venting. The action of the agita-
tor on the steam, aided by the vacuum also causes the
steam to move in a spiral fashion through the tube toward
the steam vents which are preferably located at each end
of the tube for efficient removal at low back pressure.
For needed efficient material flow between tubes
via the discharge end of one tube to the inlet of a lower
tube, Applicant designed an end discharge that has a lower
opening and an upper, preferably curved opening in the
direction of rotation of the agitator that is located
offset from the tube vertical centerline to accommodate
the material moving about the inner circumference of the
tube as it approaches the discharge end. The material --
as it moves out this volute-like discharge falls into the
inlet of the lower tube aligned with the discharge and
similarly offset from its vertical centerline for a
straight through material flow. The vent for this inlet
tube end is located on the opposite side of the centerline
to avoid the incoming material. Preferably a dam or gate
is located in the discharge to control the flow of mater-
ial through the tube. An upper vent is also provided in
each discharge end of the tube. Manifolds located at
each tube end and connected to the vents later combine to
conduct the product steam to a condenser.
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Also a part of the apparatus is a standpipe connected
to the discharge of the bottom tube to allow continuous
rendering while maintaining the vacuum in the tubes.
Suitable standpipe water sumps for each manifold collect
solid residue carry over and provide vacuum and pressure
reliefs. Preferably the material is also initially intro-
duced into the top tube of the apparatus in an air free
condition by a piston pump feed.
It is, therefore, an ob~ect of this invention to
provide a new and improved apparatus for rendering animal
material.
Another ob;ect of this invention is to provide an
apparatus having a plurality of tubes wherein the entire
length of the tubes is utilized for an improved heat
transfer to the material and the tube ends for the mater-
ial transfer and the removal of product steam.
Brief Description of the Drawings
Fig. 1 is a front elevation (partially schematic)
with portions cut away of the rendering apparatus of this
invention;
Fig. 2 is a side view taken along line 2-2 of Fig. l;
Fig. 3 is a side view (partially schematic) taken
along line 3-3 of Fig. l;
Fig. 4 is an enlarged elevation view similar to Fig.
2 of a discharge end of a chamber of the apparatus and a
related chamber inlet,
Fig. 5 is a sectional view taken along 5-5 of Fig.
4; and
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Fig.6 is a sectional view similar to Fig. 5 but of
an inlet end of a chamber.
Description of the Preferred Embodiment
.
Referring to Figs. 1-3, 10 indicates the rendering
apparatus of this invention. Apparatus 10 includes a
pair of similar lower supports 11 which consist of steel
plates welded together to form a base for the apparatus.
Specifically, a support 11 includes bottom plate 12 and
upper plate 14 with vertical reinforcing plates there-
between. Mounted on the upper side of bottom plate 12 is
generally rectangular reinforcement 15 for the chambers
or tubes of the apparatus. Reinforcement 15 which is the
same for both ends of lower tube 17 and the other tubes
of cylinders 18, 19, 20 and 21 of the apparatus, includes
end plate 23 welded to and surrounding the end of each
tube. Also welded to end plate 23 and shown best in Fig.
4 are narrow upper and lower bars 24 and 25 which with the
side bars 26 and 27 provide a box-like support structure
at each end of the tube. Via suitable fasteners in the
upper and lower bars 24 and 25, each tube is fastened to
another and thus vertically supported to form the appar-
atus starting from its base support 11.
Surrounding each tube of the apparatus is a steam
~acket 29 that extends between the end plates 23. Suit-
able pipes 30 having attached flanges provide steam com-
munication with ~acket 29 to thus heat each tube wherein
the internal temperature may vary between the tubes from
approximately 180F to 280F for the apparatus 10. The
steam may vary from 110 P.S.I. and 320F to 150 P.S.I.
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and 365F and somewhat higher.
As shown best in Figs. 1 and 2, the material to berendered is introduced into the apparatus 10, in an air
free state by preferably a piston type pump at flanged
opening 30a at the left end of top tube 21. The material
flow is in the general direction of solid line arrows
through tube 21 into tube 20 below and hence, the length of
tube 20 and down through the apparatus with eventual dis-
charge at the discharge end of tube 17. As noted previously,
the actual material flow is in a spiral fashion through each
tube because of the agitation. A suitable air lock at the
discharge end of tube 17, which may be a stand pipe, is
required to maintain the vacuum, which may be 6 - 10 inches
of H2O in the tubes.
Because of the sequential movement of the material
through the tubes, varying end covers are provided. As
shown generally in Figs. 1 and 2, each tube has a discharge
end and an inlet end. Since the tubes are identical, as are
the discharge ends except for hand, the discharge end of tube
18 will be described along with the inlet end of tube 17
associated therewith as shown in Fig. 4. It is to be noted
that the covers selected depend upon the later to be des-
cribed agitator rotation and vent connections to the mani-
folds. As noted in Fig. 2, by the arrows, the rotation is
clockwise for each tube with each agitator being driven by
independent drives at approximately 50 R.P.M. for the
apparatus described.
Figs. 4 and 5 show on a larger scale, the discharge end
of tube 18. Cover 31 is removably fastened to end plate 23
by bolts 32 and nuts 34 with a gasket 35 therebetween. Cover
31 has an opening 36 therethrough in its bottom portion and
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thus in communication with the bottom portion of the tube orchamber. Opening 36 has a lower curved surface 37 that is
generally aligned with the inner periphery of tube 18 and
starts from a vertically extending surface 38 on one side of
the vertical centerline of the tube and extends upwardly on
a radius to above the horizontal centerline of the tube and
on the opposite side of the vertical centerline thereby
following the direction of rotation of the agitator. Vertical
surfaces 38, 39, and 40, with essentially horizontal surfaces
41, 42, and 44 define a generally crescent shaped opening
with a lower portion and an upper portion for the travel of
rotatably agitated material to pass out of tube 18. Surround-
ing opening 36 and welded to cover 31 and thus forming a
part thereof, is discharge chute 45. Chute 45 has a flanged
surface 46 that is located generally on the same side of the
cover and hence tube vertical centerline as upper section
of opening 36 and as the later to be described inlet cover.
Chute 45 also has a pad 48 on an exterior thereof for
supporting pillow block bearing 49 for the agitator 50.
Agitator 50 has a longitudinally extending shaft 51 which
is sealingly located in cover 31 by a stuffing box type
seal 53. Mounted on cover 31 adjacent the lowest part of
opening 36 is adjustable dam or gate 54 which controls the
flow of material through tube 18. Access to gate 54 is
had through aperture 55 in chute 45 which is closed by cap
56 via suitable fasteners. Also a part of cover 31 is
upper vent opening 57 located in the upper portion of cover
31. Shown in dotted lines in Figure 4 and in solid lines in
Fig. 1, is angle mount 59 of agitator 50. Each angle
mount includes 4 spaced angles mounted on a supporting
cluster which is keyed to shaft 51. The angles are located
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The angles are located on the shaft depending upon its rota-
tion. As shown in Fig. 4, the angles are designed to rotate
down into the material to be rendered which on start up may
to cover the lower quarter of the tube, and by centrifugal
force maintain the material about the periphery of the tube.
Some 4 spaced angle mounts are mounted on shaft 51 inter-
spersed by 4 radially offset at preferably 45 but similar
angle mounts 60. The angles of both angle mounts overlap
longitudinally as shown in Fig. 1 which allows more angles(8)
in ~e internal tube area. Due to the size of the material
to be rendered, materials located in the clearance of the
revolution between the angle and tube inner wall are com-
pressed and thus moved longitudinally thereby assisting in
the longitudinal travel of material through the tube which
is particularly useful on discharge.
Referring to Fig. 6, therein is shown cover 61, which
defines the inlet for tube 17 and which is in communication
with the discharge of tube 18. Cover 61 is closed in its
bottom portion but has upper opening 62 which extends a
substantial portion of the width of cover 61. Below open-
ing 62 is support plate 64 attached to cover 61 and mounted
thereon is pillow block bearing 65 for shaft 51 of agitator
50. A suitable stuffing box seal seals the shaft 51 where
same extends through cover 61.
As best shown in Figs. 4 and 2, the material transition
conduit 67 is attached to surface g6 of chute 45 of discharge
cover 31 by suitable fasteners and extends downwardly to
attach to vent transition 68 of cover 61. Transition 68 is
preferably a weldment made from 8 guage hot rolled steel.
Transition 68 has a large rectangular flanged surface 69
that is constructed to enclose opening 62 of tube 17.
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Transition 68 also has an upper opening aligned with transi-
tion conduit 67 and located on the same side of the vertical
centerline for tubes 17 and 18 and the balance of the tubes.
Material can thus flow in the direction of the arrow through
the transitions, which are welded together, vertically
downward and enter into tube 17 through one side of opening
62. The other side of opening 62 is connected via vent
portion 69a of transition 68 which extends away from tube 17
and has a flanged surface 70 which is adapted via fasteners
to be connected to a vent system 71. Also connected to
vent system 71 is vent transition72 which is attached to
discharge cover 31 and encompasses upper opening 57. Vent
transition 72 is similar to transition 68 but does not have
the opening for the material travel. Only venting is per-
formed via opening 57.
Vent system 71 for removing the product steam via the
broken line arrows is shown best in Figs. 1 - 3. Vent
system 71 consists of dual vertical manifolds 73 and 74 with
an upper horizontal manifold 75 connecting same. Each tube
17 - 21 is vented at both ends at the adjacent vertical
manifold. As shown best in Figs. 1 and 3, exemplary mani-
fold 73 is supported on ~e apparatus 10 formed from the
tubes by various structural members. One of the members,
base plate 76 is attached by fasteners to support 11.
Channel 78 is attached to base plate 76 and extends upwardly
to a position short of tube 21 and is supported in the ver-
tical position by angles 79, 80, and 81, with 81 welded to
plate 82 which is bolted to reinforcing member 15. Angle
79 is bolted to channel 78, thereby connecting manifold 73
to the apparatus. Similar lower structural members also
provide support to manifold 73. Manifold 74 is similarly
supported on the other side of apparatus 10 with manifolds
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73 and 74 supporting manifold 75 which is connected to con-
ventional condenser 84.
Referring to Fig. 1, schematically shown therein, is
a water containing stand pipe pump 85 connected to manifold
73 by a pipe as large in diameter as the raw feed pipe to
collect solid carry over material and which also serves as a
positive pressure relief and a vacuum relief. Manifold 74
is intended to have a similar stand pipe pump (not shown).
Also a part of the apparatus, and shown schematically
in Fig. 3, is a suitable air lock to maintain the vacuum
applied to the vent system while discharging fat and crack-
lings which is also of the standpipe variety. The standpipe
arrangement incluaes a holding tank 86 extending below stand-
pipe 87 connected to the discharge of lower tube 17. Tank
86 which has a drain 88, maintains a desired level of fluid
fat therein that is above the lower end of the standpipe.
A conveyor 89 is provided to move the solids from tank 86.
A conventional add fat conduit 90 extending between holding
tank 86 supplies fat as needed to opening 30 via an adjust-
able speed pump 91 to prevent high protein glue from sticking
to the tube inner surfaces.
In operation, raw animal material is fed in an air free
state into flanged opening 30a connected to tube 21 which is
otherwise identical to tube 17 and is heated by jacket 29.
Simultaneously via a vent portion, product steam is vented
to manifold 74 connected via top manifold 75 to condenser
84. Agitator 50 rotating in a clockwise direction lifts the
material from the tube bottom via angle mounts 59 and 60 and
by centrifugal force throws same about the periphery of the
inner tube circumference to be heated by the jacket. As the
material continues to move into the tube, and due in part to
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the agitator action, the material moves in a spiral fashion
through tube 21 toward the discharge end. The product
steam, which occupies most of the tube volume, due to the
agitator action and the vacuum, moves in a spiral fashion
toward manifold 74 at the intake end and toward manifold 73
at the discharge end. At the discharge end of tube 21
(see Fig. 3) a certain amount of material is retained in
the tube by the gate, thereby controlling the flow, and the
balance moves down into tube 20 with simultaneous venting of
steam to manifold 73. At this point it might be noted that
the material held back by the dam is also being continuously
removed to prevent overcooking. The material then moves
sequentially through the length of the tubes down through
the apparatus. It is to be noted that the discharge end of
tube 21 is identical to discharge end of tube 18 except
for hand and hence will be detailed in connection with tube
18.
When the material reaches the discharge end of tube 18
as shown best in Figs. 1, 4, and 5, gate 54 retains an
amount of constantly renewed material in tube 18. The
material is continually being moved about the periphery
of the inner circumference of the tube. At the opening 36
in cover 31, the material enters same and as the agitator
advances also moves out the upper curved portion of the
opening via discharge chute 45 and transitions 67 and 68
into tube 17 on the same side of the centerline as chute 45.
Simultaneously steam is vented from tube 18 via vent tran-
siston 72 to vertical manifold 74. Also vent portion 69a ~ -
conducts steam from tube 17 via the part of opening 62 (not
occupied by material) into manifold 74. The material then
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moves to the discharge end of tube 17 where it leaves the
tube while the air lock maintains the vacuum condition in
the apparatus. At this end also, venting of product steam
occurs to manifold 73.
In a 5 tube apparatus as shown in Fig. 1 with each
tube having dimensions of 36 inches O.D. and 34 inches I.D.
with a length of 20 ft., 21,000 lbs. per hour of raw material
were cooked with an evaporation rate of 11,700 lbs. per
hour, which as mentioned previously represents double the
output of 6 - 24 inches O.D. 22 inches I.D. 20 ft. long
tubes with only a 53% increase in area.
Having thus described the invention, it will be clear
to those skilled in the art that various changes and modifi-
cations can be made without departing from the spirit of the
invention or the scope of the appended claims.
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