CONTINUOUSLY ACTING CENTRIFUGAL APPARATUS
Year: 1885

page_text: I, JOHN IMRAY of No 28 Southampton Buildings in the County of Middlesex,
Consulting Engineer and Patent Agent do hereby declare the nature of my
invention for " CONTINUOUSLY ACTING CENTRIFUGAL APPARATUS'
" to be as
follows:-
This invention relates to centrifugal apparatus applicable for filtering or sepa-
rating mixed substances in a fluid or partly fluid condition, the chief objects in
view being to secure continuous action, to economise power, to lessen risk of accident,
and to abridge the time required for treatment of a given quantity of material.
For this purpose, there are mounted in bearings in a framing a vertical spindle, and
on it a sleeve or tubular spindle free to revolve. Both these are driven by a single
band passing over pullies on them and over a guide tightening pulley from one
driving pulley, the two pullies being of such diameters that the sleeve is made to
revolve at a little less speed than the central spindle. On the upper end of the
spindle is fixed the porous drum which is of conical form widest at the base, and
on the upper end of the sleeve is fixed within the porous drum a drum of corre-
sponding shape baving on its periphery helical ribs standing out and almost
touching the periphery of the porous drum, these ribs being threads of a double
threaded screw. On the top of the outer drum there is a mouth piece having
within it radial ribs and above this is an outlet, provided with a regulating valve,
from a mixing or pugging vessel situated at the top of the framing. The drums
are cased over by a stationary casing having at its bottom an outlet for the liquid
ejected through the pores of the outer drum. Also from the space within the
inner drum there is a sloping outlet for discharge of the filtered or more solid
portions of the material treated. This material, after being thoroughly mixed by
helical blades revolving in the pugging vessel, flows in regulated quantity into the
Prine 1

page_text: mouth piece of the drums and by the centrifugal action of the radial ribs therein
is driven into the narrow space between the two drums. Its descent through
this space being retarded by the action of the helical ribs on the inner drum, there
is time during its passage for the filtering or separating action due to centrifugal
force. In cases where it is desired to pass purifying liquor through the material,
holes are made between the ribs of the inner drum, and the purifying liquor, led
by a pipe into the central space, issues in jets against the interior of the inner
drum and passes through its holes and through the material during its descent
between the two drums.

page_text: I, JOHN IMRAY, of N° 28 Southampton Buildings, Chancery Lane in the County
of Middlesex, Consulting Engineer and Patent Agent, do hereby declare the nature
of this invention and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:-
This invention relates to centrifugal apparatus applicable for filtering or
separating mixed substances in a fluid or partly fluid condition, the chief objects
in view being to secure continuous action, to economise power, to lessen risk of
accident, and to abridge the time required for treatment of a given quantity
of material. For this purpose, there are mounted in bearings in a framing a
vertical spindle, and on it a sleeve or tubular spindle free to revolve. Both these
are driven by a single band passing over pullies on them and over a guide
tightening pulley from one driving pulley, the two pullies being of such diameters
that the sleeve is made to revolve at a little less speed than the central spindle.
On the upper end of the spindle is fixed the porous drum which is of conical form;
widest at the base, and on the upper end of the sleeve is fixed within the porous
drum a drum of corresponding shape having on its periphery helical ribs standing
out and almost touching the periphery of the porous drum, these ribs being threads
of a double threaded screw. On the top of the outer drum there is a mouth piece
having within it radial ribs and above this is an outlet, provided with a regulating
valve, from a mixing or pugging vessel situated at the top of the framing. The
drums are cased over by a stationary casing having at its bottom an outlet for the
liquid ejected through the pores of the outer drum. Also from the space within
the inner drum there is a sloping outlet for discharge of the filtered or more solid
portions of the material treated. This material, after being thoroughly mixed by
helical blades revolving in the pugging vessel, flows in regulated quantity into the
mouth piece of the drums and by the centrifugal action of the radial ribs therein is
driven into the narrow space between the two drums. Its descent through this
space being retarded by the action of the helical ribs on the inner drum, there is
time during its passage for the filtering or separating action due to centrifugal
force. In cases where it is desired to pass purifying liquor through the material,
holes are made between the ribs of the inner drum, and the purifying liquor, led by
a pipe into the central space, issues in jets against the interior of the inner drum
and passes through its holes and through the material during its descent between
the two drums.
The principal advantages of this construction of centrifugal apparatus are as
follows: Firstly, continuous action and simplicity of the new arrangements of
parts for carrying this into effect; secondly, the suppression of all manual labour;
thirdly, a greatly increased production as compared with the size of the apparatus;
fourthly, greatly decreased danger of accidents resulting from the centrifugal action
with equal circumferential speed, such decrease being due to the small dimensions
of the apparatus and in particular to the small weight of the mass of material

page_text: under treatment at one time, and which is caused to pass through the apparatus in
a few seconds; fifthly, the reduction to a minimum of the required motive power
for producing a definite amount of work.
The construction of the improved apparatus is shewn clearly on the accom
panying drawings, in which Figs. 1 and 2 shew two vertical sections at right
angles to each other through the axis of the centrifugal drum and Figure 3 shows
a diagram plan of the differential belt and pulley motion.
R is the mixing hopper with screw stirring blades h into which is charged the
material to be treated. v is a small shoot through which the material passes from
the hopper into the upper chamber C of the centrifugal drum. n is a regulating
valve for regulating the supply of material. C is a dome shaped chamber provided
internally with ribs i and having a central boss by means of which it is fixed on
the upper end of the spindle O. This chamber is. fixed to the conical porous
centrifugal drum A to which it imparts the rotary motion of the spindle O. By
means of the ribs i i, the material, as it enters the chamber, is thrown to the outer
circumference where it is made to enter into the annular space between the two
drums A and B which latter is a second conical drum placed concentrically to A
and fixed to a hollow spindle 6 by means of which it also receives rotary motion.
Its outer surface is formed with two helical ribs 8 which start from diametrically
opposite points at the upper end and also terminate at diametrically opposite points
at the lower end in order to ensure a perfect equilibrium of the mass of the drum
relatively to its axis of rotation. These ribs are made of such a depth as to fit
against the outer drum A so as to convert the annular space between the two drums
into two closed helical channels having for their outer surfaces the filtering surface
of the drum A. The spindle O receives continuous rotary motion by means of the
pulley P¹ while the hollow spindle b receives rotary motion in the same direction
as O by means of the pulley Pш, the speed of this hollow spindle being slightly less
than that of the spindle O and consequently imparting to the drum B rotary
motion a slightly less speed than that of A. The pullies P¹ and Pш both receive
their rotary motion by means of the driving pulley P through an endless belt r,
the pulley P being of slightly larger diameter than P¹ so as to produce the above
mentioned differential speed of the two drums.
P1 is an oblique guide pulley round which the belt r passes and which is
adjustable by means of a screw T for regulating the tension of the belt r so as to
produce uniform frictional contact of the belt with all the pullies. The drums
A and B are surrounded by a casing D which can be readily removed. Its lower
part is formed with a circular trough g into which passes the liquid that is
separated by centrifugal force from the material contained in the centrifugal
drums. m is a movable cover of the casing D having a central hole that fits
against the upper end of the chamber C. K is a cylindro-conical chamber into
which falls the material discharged from the lower end of the annular space
between the drums A and B after having been subjected to the centrifugal action
thereof. L is an inclined shoot for discharging the material from the chamber K
into sacks or other receptacles, the shoot being provided with a flap for regulating
the discharge. The discharged material is thus prevented from falling upon the
driving belt and pullies.
The material to be treated having been well mixed by the blades h in the
hopper R falls through the shoot v into the chamber C whence it is conveyed into
the annular space between the druins A and B. In this space owing to the
differential speed of the two drums it is caused gradually to travel in a downward
direction through the helical passages, while at the same time it is continuously
subjected to the centrifugal action, and lastly it falls into the chamber K and is
discharged from the shoot L into receptacles below. The inner surface of the
drum A is smooth and perforated with small holes the size of which is proportioned
to the nature of the material to be treated. The drum B also has holes rather
larger in size for the passage of clarifying liquor,

page_text: It has been found from experience that the difference of speed between the
drums should be such that the drum B makes from 60 to 180 revolutions per
minute than the drum A. The helical ribs s run in the same direction as the
rotary motion of the drums; but as the drum B and its ribs have a somewhat less
speed than the drum A, it results that the helices operate as though their direction
of rotation were the reverse of that of the drum A.
This arrangement has for its object to prevent the inconvenience that would
result if the belt r were to slip upon the pullies, whereby the helical channels
would tend to cause the material to move in an upward direction instead of
regulating its descent.
From the foregoing it will be seen that the action of the helices has not for its
object to remove the material from between the drums but to retain it, in the case
where the material is of a very fluid nature and, on the other hand, to assist its
descent if the material is not sufficiently liquid. In other words, the object of the
helices is to regulate the discharge so as to render it more or less uniform not-
withstanding accidental variations in the condition of the materials treated.
An essential feature of this invention consists in the mode above described of
obtaining the differential speeds of the two drums by means of one and the same
driving belt as shown at Fig. 3, the belt being made to pass first round the
pulley P¹ on the axis O of the filtering drum, secondly round the driving drum P
and thirdly round the drum P¹¹ mounted on the hollow shaft b and driving the
drum B with the helical passages, and fourthly round the oblique guide pulley Pl
provided with a regulating screw T for regulating the tension, from which pulley
the belt passes back to the pulley P¹.
As before stated, the difference of speed between the two drums may vary from
60 to 180 revolutions per minute according to the nature of the material operated
upon. To enable the difference of speed to be varied within these limits, three or
more pullies P¹ of varying diameters less than that of P are provided so as to be
changed at will. The variations in the differential speed have for their object to
prolong or to diminish the time during which the materials treated remain in the
apparatus and are consequently subject to the action of the centrifugal force and
the clarifying liquor.
Practice has shewn that a duration of from two to twelve seconds is sufficiently
great for obtaining a perfect separation and clarifying effect. In consequence of
the conicity of the drums the diameters of which increase from the inlet to the
outlet end, the material under treatment is permitted to be somewhat opened or
spread out as it passes downwards, thus gradually increasing its permeability and
facilitating the action of the clarifying liquor upon all the particles thereof.
By means of these variations in the number of revolutions of the drums combined
with the above described action of the helical ribs the movement of the material
in the drums and consequently the yield of the machine can be regulated at will.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:-
1. Constructing continuously acting centrifugal apparatus wherein a conical
perforated or permeable centrifugal drum has within it a second conical drum,
revolving at a somewhat slower speed, the inner drum having helical ribs thereon
whereby the annular space between the drums is formed into helical passages in
which the material to be acted upon is caused to descend while it is subjected to
the centrifugal and filtering action, substantially as herein described.
2. The combination of the perforated or permeable centrifugal drum A mounted
on the spindle O with the inner drum B, with or without perforations, having
helical ribs 8 formed thereon and mounted on the hollow spindle b, arranged and
operating substantially as herein described.
3. Imparting motion at different speeds simultaneously to the two drums A
and B, by means of one and the same endless belt r, passing round pullies P¹ pul

page_text: of different diameters fixed respectively upon the spindle O and the hollow spindle b,
and round the driving pulley P and adjustable guide pulley Pu substantially as
herein described.
4. The combination with the casing D in which is received the liquid discharged
from the centrifugal drums, of the chamber L with inclined surface, for receiving
the solid material discharged from the lower end of the conical drums A and B
substantially as herein described.
5. The use of continuously acting centrifugal apparatus combined and operating
substantially as herein described with reference to the accompanying drawings,
184 1
Cac
1 1000
ABEL & IMRAY,
Agents for the Applicant.