IMPROVEMENTS IN CENTRIFUGAL MACHINES
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by Robert Lafferty at the Office of the
Commissioners of Patents on the 30th December 1880.
ROBERT LAFFERTY, of Gloucester City, in the County of Camden, State of New
Jersey, and United States of America, Engineer. "IMPROVEMENTS IN CENTRIFUGAL
MACHINES."
My Invention relates to machines of the class in which the separation of
commingled liquids and solids, or the drying or draining of wet material of various
descriptions, is effected by the action of centrifugal force generated by the rapid
rotation of a vessel in which the matters to be treated are contained. In the use
of machines for this purpose as heretofore constructed, so far as my knowledge and
information extend, frequent stoppages are necessary to admit of the removal of
the dried material and the insertion of fresh charges. The loss of time thereby
involved materially reduces the efficiency of the apparatus in correspondingly
diminishing the amount of its daily product, and the attention and labor of an
operator is moreover required for charging and discharging.
The object of my Invention is to provide a centrifugal machine in which the
separation of liquid from solid matters may be effected continuously, and the
necessity of stoppages during its operation avoided, by the provision of simple and
effective means for maintaining a continuous feed of the material to be treated and
a continuous discharge of the separated liquid and solid constituents thereof.
To this end my improvements consist in the combination of a rotating receiving
vessel, a series of separating vessels connected to and communicating therewith, and
a fixed case having separate receptacles and discharge passages for the separate
constituents of the charge.
My improvements further consist in the combination of a rotating receiving
vessel, a series of separating vessels, and mechanism by which mixed solid and
liquid ingredients fed continuously to the receiving vessel are conducted continuously
therefrom, exposed to the separating action of centrifugal force, and continuously
and separately delivered to separate receptacles in a fixed case.
In the accompanying Drawings, Figure 1 is a vertical central section through a
centrifugal machine embodying my improvements; Figure 2, a plan or top view of
the same; Figure 3, a longitudinal central section on an enlarged scale through a
Price 6dı

page_text: portion of one of the separating vessels and its driving gear; and Figure 4, a
transverse section on a similar scale through the same.
°
To carry out my Invention I provide a receiver A, which has an open wide
mouthed top, and is, except as presently to be described, entirely closed on its sides
and bottom. The form shown in the Drawings is a convenient though not an
essential one, as the receiver might, if desired, be made cylindrical or of any other
form in which all borizontal sections through its walls would present circles
concentric with its axis. The receiver A is firmly fixed upon the upper end of a
vertical shaft A¹, which passes centrally through the bottom of the receiver, and is
secured thereto by a screw thread and a nut a. The lower end of the shaft A¹
bears on a step a', and the shaft rotates within a lower bearing a², fitted within a
box a³, secured to the legs or frame A² of the machine, being maintained and guided
in vertical position by a hollow shaft B through which it passes, said hollow shaft
rotating within a tapered gland or bushing a³ fitted in a bearing a, depending
centrally from a horizontal plate a connecting the legs A² at their upper ends.
The
A series of separating vessels C, each of which communicates at its inner end
with the receiver A, and near the bottom thereof is attached to said receiver, the
several vessels being arranged radially to the axis thereof, and in this instance in
inclined position parallel to the conical periphery of its upper portion.
separating vessels C are cylindrical metallic tubes, which at their inner ends are
mounted so as to rotate freely on tubular journals a projecting from the lower
portion of the receiver A, and at their outer ends are similarly fitted in bearings a
depending from the periphery of the upper portion of the receiver. The tubes C
are perforated with a number of small openings c throughout that portion of their
length which is between their end bearings, and each is preferably lined with a
cylinder of wire gauze or netting c'. A screw or spiral blade C¹ of metal is
inserted and secured in each of the tubes C, forming a continuous spiral channel
open at both ends along the same.
A driving pulley A³ is secured upon the shaft A' of 'the receiver A, the upper
face of its hub forming a step or bearing for the hollow shaft B, upon the lower
end of which are secured the cone pulleys b. A bevel gear B₁ is formed upon or
secured to the upper end of the shaft B, and meshes 'with a series of corresponding
pinions C³, each of which is secured upon the inner end of one of the separating
vessels C. A vertical counter shaft D is mounted in bearings & secured to the
frame A of the machine, and has secured upon it a driving pulley D¹, around
which passes a belt transmitting power from a prime mover.
Rotation is imparted
from the counter shaft D to the receiver shaft A' by a belt D' passing around a
pulley D³ on the counter shaft, and around the pulley As on the shaft A', and the
tubular shaft B is independently rotated by a belt D' connecting the cone pulleys b
of the shaft B with cone pulleys D5 on the counter shaft D.
By the above described driving mechanism it will be observed that two separate
movements of rotation are imparted to each of the separating vessels C, one
coincidently with the receiver A, about the axis of the latter, and another through
the bevel gears B and C, about its own axis, the ratio of the latter movement to
the former being susceptible of variation by changes of the position of the belt D'
on the cone pulleys b and D³.
The receiver A and its separating vessels C are inclosed in a fixed outer case
composed of an upper cylindrical receptacle E, into which the outer ends of the
separating vessels C project, and a similar lower receptacle E¹ surrounding the
perforated portions of the vessels C. The lower receptacle E' is closed at bottom
by the plate a, which connects the legs A² of the machine, and is separated at top
from the receptacle E by a flange e. A discharge opening or nozzle e' is formed
in the lower portion of the receptacle E, and a discharge nozzle e² is provided
upon the lower receptacle E¹. A scraper may be employed for the purpose of
removing the separated solid material from the upper receptacle E by traversing
the annular space in the receptacle E around the flange e, and sweeping any
material lying within said space into the discharge nozzle e¹.

page_text: In the operation of the machine, rotation having been imparted to the counter
shaft D, and thence to the receiver and separating vessels C, the raw or undrained
material is fed into the mouth of the receiver A, preferably by a pipe or conduit
having its opening above the centre thereof, and under the influence of the cen-
trifugal force developed by the rotation of the receiver is projected into the open
inner ends of the separating vessels C, and gradually propelled outward through
the same. The spiral blades C₁ interpose barriers to the direct passage of the
undrained material to the open outer ends of the vessels C, and compel its traverse
to be made through the spiral spaces formed in the tubes by the convolutions of
the blades C, and substantially over the entire perforated surfaces of the tubes,
the only portions thereof which are intercepted being those covered by the
narrow edges of the blades C¹, the length of such traverse being proportionate
to the pitch of the blades, and its duration to the relative speeds of rotation of
the receiver and of the separating vessels about their respective axes.
It will be obvious that by increasing or decreasing the rotative speed of the
hollow shaft B and its attached bevel gear B¹ relatively to that of the shaft A¹ and
receiver A, the number of revolutions about their own axes made by the separating
vessels C during each revolution of the receiver will be increased; that the more
nearly the rotative speeds of the shafts A and B approximate, the less will be the
number of axial revolutions of the separating vessels C during each revolution of
the receiver A, and that the direction of axial rotation of the vessels C will be
changed according as the speed of the shaft B is greater or less than that of the
shaft A¹ In the outward traverse of the material fed to the receiver through the
vessels C its liquid and solid constituents are separated by centrifugal action, the
former passing through the wire netting and perforations c into the receptacle E¹,
and the latter passing out of the open ends of the vessels C into the receptacle E¹.
Moreover, the tendency of the solid portions of the charge to bank up and cake
against the walls of the separating vessels is effectually overcome by the constant
changes in their positions due to the axial rotation of the vessels, and the continua!
breaking up of the solid masses greatly facilitates the complete extraction of liquid
therefrom.
It will be further obvious that a continuous feed proportioned to the capacity
of the vessels C may be maintained, and a corresponding continuous discharge of
the separated ingredients effected, and therefore that no stoppage of the machine
for the purpose of supply or discharge is requisite.
The machine being adapted to the treatment of various materials, as, for
example, concentrated cane-juice, beet root, pulp, wet grain, &c., the axial speed of
the separating vessels and the fineness of their perforations will vary with the
character of the material acted on, and are matters within and to be decided by
the ordinary skill of those familiar with the construction of centrifugal machines.