Improved Centrifugal Apparatus for the Continuous Separation from Liquids of Matters in Suspension therein.
Year: 1895

page_text: Date of Application, 5th Mar., 1895-Accepted, 6th Apr., 1895
Improved Centrifugal Apparatus for the Continuous Separation from
Liquids of Matters in Suspension therein.
I, GEORGE CROYDON MARKS, of 18 Southampton Buildings, London W.C.
Consulting Engineer and Patent Agent (communication from Société
E. Wauquier & Fils, of Lille, Nord, in the French Republic), 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:—
The separation of two liquids of unequal density or specific gravity from each
other, through the medium of centrifugal force, has in many casos heen success-
fully effected within the last few years, a somewhat wide range of apparatus having
been devised for the purpose. Thus centrifugal cream separators or skimmers may
be mentioned as an instance of apparatus of this class which are by this time
finally adopted in practice.
But the same success has not as yot attended the efforts made to separate from
liquids the solid matter or, indeed semi-liquid substancos, which may be in
suspension in such liquids, and the reason was that, in the apparatus hitherto experi-
mented on with this object in view, it was impossible to cause the discharge to take
place automatically, owing to the rapid obstruction to which the discharge channels
or pipes became liable, as the matter which was being separated from the liquid
grew thicker or more consistent.
When, therefore, centrifugal apparatus were employed before, in effecting such
separation by decanting off the liquid, it was necessary to conduct the operation
intermittently and, at each stoppage or pause, to remove the solid matter having
collected on, and adhering to, the walls of the rotary cylinder or drum. Such a
discontinuous mode of operation necessarily reduced the useful effect and yield
of the centrifugal apparatus in an appreciable degree, while at the same time it
involved a considerable consumption of labour. The consequence was, that in a
great many cases, it was preferred to resort to such decautation as the weight
of the matter to be separated would admit of.
In the centrifugal apparatus heretofore tried as means for the continuous decen-
tation of liquids, the channels serving for the discharge of the deuse bodies or
substances separated from such liquids were apt to become obstructed mainly
owing to the fact that they were bent inwardly, froin the periphery towards the
centre of the cylinder or drum, so that the centrifugal action went on diminishing
in proportion as the matter to be discharged entered the said chanuels.
Now in the centrifugal apparatus hereinafter described, the obstruction of the
discharge chaunels is entirely obviated, and the comparatively dense substances to
be separated, by being subjected to the direct action of a gradually increasing
centrifugal force, are discharged in a continuous and automatic manner.
The invention will be best understood by reference to the accompanying
drawings, in which—
Figure 1 is a vertical section on line u v z, Figure 2, of one form of my
improved decauting and separating apparatus, arranged to turn on a vertical axie.
Figure 2 is a plan thereof, a portion being cut away to enable the liquid supply
and discharge orifices to be seen.
Figure 3 is a vertical section of an arrangement carried out on the same system
but comprising a star-shaped drum.

page_text: Figure 4 is a plan corresponding to Figure 3, with the lid removed.
Figures 5 and 6 represent modifications of the form of drum turning on a vertical
axis, and
Figure 7 shows the form of apparatus which comprises a horizontal shaft.
The liquid to be decanted or purified is admitted through the funnel A
(Figures 1 and 3) which may be either movable and dependent on, or connected
with, the drum; or independent thereof, and stationary, so as not to alter its
position during the rotation of the drum; or the liquid may be admitted through
a pipe B (Figures 5 and 7). It is thus conducted into the drum wherein it undergoes
the action of centrifugal force.
But for n considerable reduction of the peripheral sectional area of the revolving
drum, the whole of the liquid admitted would immediately he discharged
without undergoing any separation. As shown, however, in Figures 1, 3, 5 and 7,
the said sectional area, owing, to the peculiar shape of the drum is more and more
contracted as the diameter of the drum increases. Besides, in view of the fact
that such sectional area may become liable to obstruction, through being reduced
beyond a certain limit, a suitable number of partitions or bridges CC (Figure 2)
are provided to reduce the sectional area of the discharge channel, while retaining
in the periphery a number of orifices E of such dimensions as to obvinte any danger
of obstruction.
Special partitions, such as indicated, may, however, be dispensed with, while
the advantage arising from the gradual contraction of the discharge channels may
be retained by constructing the drum in the shape of a star, as shown in
Figure 4.
Fron Figure 6 it will be seen that, instead of orifices of fixed dimensions, in
controlling which some difficulty may be experienced, removable pipe connections
or nozzles, such as J, may be employed, so that the size or capacity of the
discharge-orifices may be varied and adjusted to suit requirements by simply
exchanging the nozzles or pipes.
The operation of the improved apparatus will be readily understood.
The heavier parts of the mixture introduced into the drum will be first (by
centrifugal force) driven towards the periphery, and if the amount of mixture
supplied be at all sufficient, there will develop two currents within the drum; one
portion (being the denser of the two) will tend to escape through the outlets E,
while the remaining part, of less density, will be forced towards the centre of the
drum, and thence discharged through D.
It will therefore be seen that, according to the quantity of liquid to be treated
and the proportion of solid or semi-liquid matter to be separated, the number and
sectional area of the said outlet-orifices E, and also the diameter and speed of
rotation of the drum, may be regulated.
The less the difference of density between the liquid and the substances to be
separated, the more powerful should be the notion of the centrifugal force; or the
Liquid may be left in the drum for a proportionately extended space of time. The
latter result may easily be attained either by increasing the capacity of the drum,
'or by reducing its diameter at D (which is equivalent).
It will be understood that, according to the nature of the liquids to be treated,
the shape of the revolving drum may vary within somewhat wide limits, the
essential condition being that such shape should enable the solid or semi-liquid
molecules to slide or sweep along the walls of the drum, so as (under the
progressively growing energy of the contrifugal force) to be conducted to, and
allowed to accumulate at, the points where the maximum effect of the centrifugal
force is attained.
In proportion as the matter to be extracted becomes thicker, the wall should
more and more approach the position of a perpendicular in relation to the axis of
rotation of the drum, or in otlier words be more nearly at right angles thereto.
This apparatus may be employed in all cases where it is desired to separate from
cach other, either two liquids or a liquid from a solid or semi-solid substance.

page_text: Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be employed, I declare that what [
claim is
1. Centrifugal apparatus for the continuous decantation of liquids and the
automatic separation of matter in suspension therein; such apparatus boing
adapted to effect the discharge of the denser parts of the mixture undor treatment
by the direct and progressive action of centrifugal force; and having for its main
feature a drum with contracted discharge orifices arranged at the part of the
periphery which is furthest from the axis of rotation, so that the denser matter may
go on accumulating towards the said discharge orifices, where bridges or partitions
are provided for its subdivision; which partitious at the same time enable the
sectional area of the said orifices to be sufficiently increased to avoid obstruction ;
while the parts of less density rise within the drum and issue through its central
orifice.
2. Centrifugal apparatus for the continuous decantation of liquids and the
automatic separation of matter in suspension therein, substantially as hereinbefore
doscribed, but the drum of which assumes the shape of a star, as illustrated in
Figures 3 and 4, such arrangement being intended as a substitute for the bridges
or partitions referred to in the first claim.
Dated this 6th day of March 1895
MARKS & CLERK,
18, Southampton Buildings, London, W.C., and
13, Temple Street, Birmingham, Agents for the Applicant.