IMPROVEMENTS IN FILTERING LIQUIDS, AND IN THE MACHINERY OR APPARATUS EMPLOYED THEREFOR, BEING MORE ESPECIALLY ADAPTED FOR FILTERING SACCHARINE SOLUTIONS
Year: 1873

page_text: LETTERS PATENT to William Renny Watson (of the Firm of Mirrlees,
Tait, & Watson) of Glasgow, in the County of Lanark, North
Britain, Engineer, and Robert Andrew Robertson, Manager to the
said Firm, for the Invention of "IMPROVEMENTS IN FILTERING LIQUIDS,
AND IN THE MACHINERY OR APPARATUS EMPLOYED THEREFOR, BEING MORE
ESPECIALLY ADAPTED FOR FILTERING SACCHARINE SOLUTIONS "
Sealed the 22nd August 1873, and dated the 17th March 1873.
PROVISIONAL SPECIFICATION left by the said Wiliam Renny Watson
and Robert Andrew Robertson at the Office of the Commissioners
of Patents, with their Petition, on the 17th March 1873.
We, WILLIAM RENNY WATSON, (of the Firm of Mirrlees, Tait, &
Watson), of Glagow, in the County of Lanark, North Britain, Engineer,
and ROBERT ANDREW ROBERTSON, Manager to the said Firm, do hereby
declare the nature of the said Invention of "IMPROVEMENTS IN FILTERING
LIQUIDS, AND IN THE MACHINERY OR APPARATUS EMPLOYED THEREFOR, BEING MORE
ESPECIALLY ADAPTED FOR FILTERING SACCHARINE SOLUTIONS," to be as follows,
that is to say:-

page_text: adapted for filtering saccharine solutions, and it consists in improvements
in that class of apparatus in which the liquid is filtered through cloth or
other textile fabrics.
Under this Invention the cloth or other fabric is passed over guide
pullies on to the perforated periphery of a hollow drum revolving
continuously or intermittently in a tank containing the liquid to be
filtered. A portion of the circumference of the drum is situate below
the surface of the liquid, which is caused to filter through the cloth and
perforations into the interior of the drum by the pressure due to the head
of liquid alone, or by the addition of atmospheric pressure induced by
exhausting or partially exhausting the air from the interior of the drum
by means of an air pump or other exhausting apparatus communicating
therewith through the journal of the drum, through which also the
filtered liquid is delivered into a suitable receptacle. The cloth or other
fabric after having passed through the liquid contained in the tank may
be delivered direct from the drum on to a reel or its equivalent, and
thence removed for the purpose of washing from it the dirt filtered from
the liquid preparatory to its again passing round the filtering drum; or
previous to such washing, when the substance in the solution being
filtered is valuable as in the case of saccharine solutions, the cloth may
be conducted through apparatus by which the sugar or other substance
contained in the liquid saturating the cloth may be recovered, and which
apparatus may constitute a separate machine, or be attached to the filter,
thereby rendering the process continuous.
In recovering the sugar or other substance from the cloth it is passed
through a trough filled with water, and provided with obstructions
arranged to cause the water to move circuitously and in a direction
opposite to that of the cloth. Steam may be passed into the tank to
assist in separating the sugar or other substance from the dirt on the
cloth without disturbing the said substance, or the employment of water
may be dispensed with, and the separation effected by steam alone.
After leaving the tank or vessel the cloth is passed round one or a
series of drums similar to the filtering drum herein-before described,
situate in a tank or tanks containing water, which in filtering through
the cloth removes the sugar or other substance remainining thereon,
the said substance passing with the water into the interior of the drum
or drums, and the solution thus obtained is caused to circulate back to

page_text: the tank containing the filtering drum first described. The cloth after
the sugar or other substance is removed therefrom is wound on to a reel
or its equivalent, and washed by suitable means, after which it is again
employed as herein-before set forth.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Renny Watson and Robert Andrew
Robertson in the Great Seal Patent Office on the 16th September
1873.
· TO ALL TO WHOM THESE PRESENTS SHALL COME, we, WILLIAM
RENNY WATSON, (of the Firm of Mirrlees, Tait, and Watson), of
Glasgow, in the County of Lanark, North Britain, Engineer, and
ROBERT ANDREW ROBERTSON, Manager to the said Firm, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventeenth day of March, in the year
of our Lord One thousand eight hundred and seventy-three, in the
36th year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto us, the said William Renny Watson and Robert
Andrew Robertson, Her special license that we, the said William
Renny Watson and Robert Andrew Robertson, our executors, admin-
istrators, and assigns, or such others as we, the said William Renny
Watson and Robert Andrew Robertson, our executors, administrators,
or assigns, should at any time agree with, and no others, from time to time
and at all times thereafter during the term therein expressed, should
and lawfully might make, use, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and Isle
of Man, an Invention for “IMPROVEMENTS IN Filtering Liquids, AND IN THE
MACHINERY OR APPARATUS EMPLOYED THEREFOR, BEING MORE ESPECIALLY ADAPTED
FOR FILTERING SACCHARINE SOLUTIONS," upon the condition (amongst others)
that we, the said William Renny Watson and Robert Andrew Robertson,
by an instrument in writing under our hands and seals, should par-
ticularly describe and ascertain the nature of the said Invention, and
in what manner the same was to be performed, and cause the same to be

page_text: filed in the Great Seal Patent Office within six calendar months next
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that we, the said William Renny Watson and
Robert Andrew Robertson, do hereby declare the nature of our said
Invention, and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement,
reference being had to the accompanying Drawings, and to the letters
and figures marked thereon, that is to say :-
Our said Invention, which relates to the filtration of liquids, is
specially adapted for filtering saccharine solutions, and it consists in
improvements in that class of apparatus in which the liquid is filtered
through cloth or other textile fabrics.
Under this Invention the cloth or other fabric is passed over guide
pullies on to the perforated periphery of a hollow drum revolving
continuously or intermittently in a tank containing the liquid to be
filtered. A portion of the circumference of the drum is situate below
the surface of the liquid which is caused to filter through the cloth
and preforations into the interior of the drum, by the pressure due
to the head of liquid alone, or by the addition of atmospheric pressure
induced by exhausting or partially exhausting the air from the interior
of the drum by means of an air pump or other exhausting apparatus
communicating therewith through the journal of the drum, through
which also the filtered liquid is delivered into a suitable receptacle;
the cloth or other fabric after having passed through the liquid con-
tained in the tank may be delivered direct from the drum on to a
reel or its equivalent, and thence removed for the purpose of washing
from it the dirt filtered from the liquid preparatory to its again passing
round the filtering drum; or previous to such washing when the
substance in the solution being filtered is valuable, as in the case of
saccharine solutions, the cloth may be conducted through apparatus
by which the sugar or other substance contained in the liquid saturating
the cloth may be recovered, and which apparatus may constitute a
separate machine, or be attached to the filter, thereby rendering the
process continuous.
In recovering the sugar or other substance from the cloth it is passed
through a trough filled with water, and provided with obstructions
arranged to cause the water to move circuitously and in a direction

page_text: opposite to that of the cloth. Steam may be passed into the tank
to assist in separating the sugar or other substance from the dirt on
to the cloth without disturbing the said substance, or the employment
of water may be dispensed with and the separation effected by steam
alone.
After leaving the tank or vessel the cloth is passed round one or a
series of drums similar to the filtering drum herein-before described
situate in a tank or tanks containing water, which in filtering through
the cloth removes the sugar or other substance remaining thereon, the
said substance passing with the water into the interior of the drum
or drums, and the solution thus obtained is caused to circulate back
to the tank containing the filtering drum first described. The cloth,
after the sugar or other substance is removed therefrom, is wound on
to a reel or its equivalent, and washed by suitable means, after which
it is again employed as herein-before set forth.
In some cases the trough into which the cloth first passes from the
filtering drum may be dispensed with.
And in order that our said Invention may be properly understood,
we now proceed more particularly to set forth the system, mode, or
manner in or under which the same is or may be used or practically
carried into effect, that is to say :-
On Sheet 1 of the Drawings hereunto appended Figure 1 is a longi-
tudinal section shewing a part in elevation of our improved apparatus
for filtering liquids; Figure 2 is a transverse section of the same on the
line x, x, Figure 1.
As shewn by the Drawings the filtering cloth or fabric A is passed
over guide pulleys, which are not shewn on Sheet 1 of the Drawings,
on to the perforated periphery of a filtering drum B which revolves
continuously or intermittently on friction rollers or other suitable
bearings B¹ in a tank C containing the liquid to be filtered. The
filtering drum B is composed of two ends a, between which are placed
a series of buckets 6 so curved orshaped as to retain and lift the liquid
which filters into (them as the drum revolves.
The buckets bare
secured to the ends a and to a hollow central journal D with which
the buckets also communicate by means of ports c. That part of
the interior of the journal D at which the ports c communicate
therewith is bored conically, and in the part so bored is fitted a

page_text: г
hollow conic frustrum which is divided into two chambers e, one of
which communicates by means of an internal pipe or passage E with
one of the hollow journals D, whilst the other communicates by means
of a similar internal pipe or passage E¹ with the opposite journal D.
The hollow conic frustrum d is provided with two ports f and f
respectively, and is stationary, whilst the filtering drum C is revolved
round it, thereby causing each of the buckets 6 to be in turn placed
in communication with the internal pipes or passages E and E¹.
The periphery of the filtering drum B is covered with either perforated
sheets of copper, wire gauze, or other suitable perforated material g,
which is supported on bars h formed for that purpose on the back
of the buckets b. Over the perforated sheets of copper, wire gauze,
or other suitable perforated material g one or more thicknesses of
flannel, felt, or other porous material i is or are wound. The per-
forated sheets of copper or gauze g, and flannel or other suitable
material i are secured in position by means of metallic bars k screwed
on or otherwise fixed to the edges of the buckets b, the bars / also
serving to make a tight joint between the buckets 6. The internal
pipe or passage E¹ communicates by means of a branch pipe F with
two safes G, herein-after more particularly referred to, which again
communicate with an air pump or other exhausting apparatus by
means of the branch pipe H. The internal pipe or passage E is the
outlet for the filtered liquor. The branch pipes F and H. are provided
with stop-cocks i which are connected together by a link m, so as
to be actuated by the attendant at one operation. The filtering drum B
is driven by means of a belt passing round a fast pulley I which is
carried on a shaft n supported in a bracket J which is attached to the
tank C; situated on the shaft n is a spur pinion K which gears into a
spur wheel L carried on one end of the hollow journal D. As the
pulley I revolves a slow revolving motion is transmitted through the
pinion K. and spur wheel L to the filtering drum B.
In using the apparatus herein-before described and illustrated on
Sheet 1 of the Drawings, the tank C is nearly filled with the liquid to be
filtered, and the filtering drum B is rotated either continuously or inter-
mittently therein, a portion of its periphery being situated below the
level of the liquid to be filtered, as shewn. The liquid filters through
the cloth A into the interior of the drum B, either by the pressure due to
the head of the liquor alone or by the addition of atmospheric pressure,

page_text: induced by exhausting or partially exhausting the air from the whole
or part of the interior of the drum B through the port f and pipe
or passage E¹ and connected apparatus leading to the air pump or
exhauster. The liquid filtered into the drum B is received by the
buckets b, which retain it until by the revolution of the drum B they have
reached the level at which it flows through the ports c into the upper
chamber of the hollow conic frustrum D, and thence through the pipe
or passage E into any convenient receptacle.
It is preferred to arrange the ports and division in the conic frustrum D
so that each bucket of the drum B shall communicate with the ex-
hausting apparatus while the cloth covering the filtering entrance to the
bucket is below the level of the liquid to be filtered, and for as long
after that surface rises above the level of the liquid as will suffice to
drain from the cloth as much as possible of the liquid with which it is
saturated. The safes G which are fitted with gauge glasses M are pro-
vided so that in the event of the filtered liquid being drawn over towards
the exhauster it will be caught and returned by means of a pipe N to
the receptacle for filtered liquor. The pipe N is also provided with stop--
cocks O which are connected together by a link p so as to work alter-
nately. In place of removing the filtered liquor in the manner herein-
before set forth, that is, through the passage E, it may be removed through
the passage E¹ and safes G.
'
The filtering cloth A on reaching the top of the filtering drum B may
either be delivered off on to a winding drum and then removed for the
purpose of washing from it the substance filtered from the liquid pre-
paratory to its again passing round the filtering drum B, or previous to
such washing when the substance in solution is valuable, as in the case of
saccharine solutions, the dirty filtering cloth must first be washed in such
a manner as to recover from it and from the dirt or sediment thereon
the sugar or other substance it contains. The apparatus by means of which
this is effected is shewn on Sheet 2 of the Drawings; Figure 1, being a
side elevation with a part in section, Figure 2 a front elevation thereof,
and Figure 3 a plan of the same. As shewn by these Figures rolls of
clean filtering cloth A are preferably situated at the back of the tank Ơ,
the filtering cloth A passing over a guide pulley P on to the periphery
of the filtering drum B, from which it is conducted into a trough Q
which is fitted with divisions or obstructions Q'arranged to cause the
water passing along it to move in a circuitous manner and in a :

page_text: direction opposite to that of the cloth A. The cloth A is conducted
from the trough Q over a guide pulley p¹ on to a hollow washing
drum R, which revolves on antifriction rollers q or in other suitable
bearings in a tank S, which is filled with hot or cold water or other
required liquid. The washing drum R which may either be exhausted t
or not is constructed similar to the filtering drum B. The water as it
filters through the cloth into the interior of the drum R removes the
sugar or other substance it may still contain, and this is delivered
through the hollow journal of the drum R by means of a pipe » into
the end of the trough Q nearest to the washing drum R, from which it 1
passes down the trough Q, gathering sugar or other substance which the
advancing cloth may contain, until it reaches the end, where it is delivered
by means of a pipe s into a mixing tank T where the supply of liquor
to be filtered is so regulated as to density, that it, together with the water
containing the substance washed from the cloth, imparts the density which 1
the filtered liquor is required to have.
The cloth A after passing over the washing drum R is brushed by
means of a revolving brush U to remove from it the grosser part of the
dirt or sediment filtered from the liquor, and it is then passed over a
guide pulley U¹ and wound on to a roller or rollers V, which when full 2
is or are removed to any suitable apparatus where the cloth A is washed
preparatory to being used again.
If found necessary the trough Q may be covered, and steam passed
through it either alone or in conjunction with water to assist in removing
the sugar from the cloth.
2
The washing drum R is driven by means of a pitch chain W which
passes round the hollow journal D of the filtering drum B, and round
the similar hollow journal of the washing drum R, as shewn at Figure 3,
Sheet 2 of the Drawings. The rolls of clean and dirty filtering cloth
may be arranged so that as soon as one is exhausted or filled another 3
can be substituted and the process rendered continuous. The speed of
the filtering and washing drums, and the depths of liquor and water in
the tanks is adjusted to correspond with the character of the liquid
to be filtered. In some cases the trough Q into which the cloth first
passes from the filtering drum B may be dispensed with.
3
It is to be understood that in place of using a textile fabric as the
filtering medium, felt, paper, or other similar fabric in continuous lengths
may be substituted therefor,

page_text: Having now described and particularly ascertained the nature of our
said Invention, and the system, mode, or manner in or under which the
same is or may be used, or practically carried into effect, we would
observe in conclusion that what we consider to be novel and original and
therefore claim as the Invention secured to us by the herein-before in
part recited Letters Patent is,-
First. The arrangement and construction of apparatus for effecting
the continuous filtration of liquids or solutions substantially as herein-
before described and shewn upon the annexed Sheets of Drawings.
Second. The construction of the revolving filtering drum B, journals D,
and hollow conic frustrum, or any mere modification thereof.
In witness whereof, I, the said Robert Andrew Robertson, on behalf
of myself and the said William Renny Watson, have hereunto set
my hand and seal, this Fiftheenth day of September, One thousand
eight hundred and seventy-three.