IMPROVEMENTS IN FILTERS
Year: 1885

page_text: "
I WALTER OLDHAM of 96 Clyde Road Didsbury, Manchester in the County of
Lancaster Engineer do hereby declare the nature of the said Invention for
IMPROVEMENTS IN FILTERS" to be as follows:
My Invention relates principally or more particularly to the filtration of water,
oils, sugar, syrups and other liquids from which it is desired to extract color
as well as other impurities and has for its object to obtain this result in a rapid,
cheap and efficient manner. In a former Invention for which Letters Patent
numbered 7831 of the year 1884 have been granted to me and in improvements
on such former Invention for which in the same year I made an application
bearing the number 16326 for Letters Patent. I sought principally to deal with
large quantities of water by means of combinations of filters the units in which
combinations could be emptied and recharged in succession so that a continuous
filtration could be maintained for an indefinite period without the complete
apparatus ceasing its operations. According to my present Invention each filter
is provided with three pervious cylinders one within the other. The central
cylinder is a perforated or pervious pipe into which the filtered water percolates
and which communicates with the filtered water mains as in my former inventions.
Surrounding this are outer and inner perforated or pervious cylinders. Between
the central pipe and the inner cylinder is an annular space which I fill with
a filtering medium and between the said inner cylinder and the outer cylinder is a
second and outer annular space which I fill with a coarse medium. The inner
space I prefer to charge with finely divided or powdered animal charcoal in
combination with granular wood charcoal or carbonised saw dust. The animal
charcoal may be the refuse or fine dust charcoal which is separated from the
granular charcoal when preparing it for the use of the sugar refiners or it may be
otherwise derived or be specially propared for my purpose. The wood charcoal is
most conveniently obtained by carbonising wood saw dust and for the purposes
of my Invention the residue from the operation of wood distillation in the
manufacture of pyrolignous acid and other products is suitable or I may use
carbonised dye-wood, refuse or specially carbonised saw-dust. I may enclose the
central pipe in an envelope of flannel or other suitable material which while
hindering the fine powder in the filtering medium from passing out with the
filtered liquid will not materially obstruct the passage of the latter. I mix the
I Dien

page_text: wood charcoal together with a proportion of the animal charcoal with water and
pour the mixture into the filter allowing it to settle down by drainage. The
granules of wood charcoal become coated with the animal charcoal or otherwise
the latter is retained within the interstices of the former and I obtain a filtering
medium which is very porous. The outer annular space I fill with wood charcoal
or with saw dust or other coarser filtering medium without the animal charcoal
or with a lesser proportion of the same. I mix the charcoal or saw dust with
water and pour into the space as when filling the inner space. When the filter is
in use the water passes first through the outer filtering medium and deposits
therein the slime, mud or grosser impurities. The partly filtered water then
percolates through the inner medium which is adapted to complete the filtration
and not only to render the effluent water clear and limpid but by removing organic
matters to render the water more pure and wholesome and therefore more suitable
for human consumption. I so construct the filter as that the two media can be
separately removed from the filter when it is desirable to cleanse the filter. The
medium in the outer space being charged with slime or mud may be thrown away
or be cleansed for further use. The more costly medium in the inner space may
be washed and returned to the filter or be used again. I make the two inner
cylinders to lift out or I make the outer cylinder removable or I form a door or
doors in the outer cylinder or in the two outer cylinders. I prefer to make one
or both of the pervious cylinders taper so that the space to contain the filtering
medium may be wider at the bottom than at the top to facilitate the packing or
settling of the medium. In some cases wherein mechanical filtration is alone
required I dispense with the use of animal charcoal and charge the inner space
with a finer medium separated by sieving or otherwise obtained, the outer space
being charged with the coarser medium. For some purposes it may be desirable to
have more than two spaces to contain filtering media as for example when filtering
sewage. I do not confine myself to the vertical position of the filters constructed
as herein described nor to their use as low pressure filters as I may enclose them
in cases or chambers into which the water to be filtered is admitted at a pressure
above the atmospheric pressure suitable cocks or valves being provided in lieu of
the conical plug used in my said former invention. I do not confine myself to the
cylindrical formation of the pervious walls, partitions and cases of the filters.
I may use the combined animal charcoal and wood charcoal in the described
manner in filters not provided with an inner and an outer space for filtering
medium or otherwise differently constructed from the filter herein described.
Although I have designed my improved filters for use principally in the filtration
of water they may be used in the filtration of oil, juice, syrup or other liquids.
Dated this 10th day of Mo. 100%

page_text: I WALTER OLDHAM of 96 Clyde Road Didsbury, Manchester in the County of
Lancaster Engineer do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN FILTERS" and in what manner the same is to be performed
to be particularly described and ascertained in and by the following statement and
accompanying drawings:―
My Invention relates principally or more particularly to the filtration of water,
oils, sugar, syrups and other liquids from which it is desired to extract color as well
as other impurities and has for its object to obtain this result in a rapid, cheap and
efficient manner. In a former Invention for which Letters Patent numbered 7831
of the year 1884 have been granted to me and in improvements on such former
invention for which in the same year I made an application bearing the number
16326 for Letters Patent. I sought principally to deal with large quantities of
water by means of combinations of filters, the units in which combinations could be
emptied and re-charged in succession so that a continuous filtration could be main-
tained for an indefinite period without the complete apparatus ceasing its operations.
In my present invention each filter is provided with three or it might be a greater
number of concentric pervious cylinders or cases containing filtering media of
different degrees of fineness or of uniform consistency. The inner space is prefer-
ably charged with finely divided or powdered animal charcoal in combination with
granular wood charcoal or carbonised saw dust and the outer case with coarser
vegetable matter or charcoal alone. The said vegetable charcoal may be conve-
niently obtained by carbonising wood saw dust. I may enclose the central pipe in
an envelope of flannel or other suitable material to prevent the fine powder from
passing out with the filtered liquid. The two media can be separately removed
from the filter when it is desirable to cleanse the filter or change one of the filtering
beds. I prefer to make one or both of the pervious cylinders taper so that the
space to contain the filtering medium may be wider at the bottom than at the top.
And in order that my said invention may be properly understood I will now
proceed more particularly to describe the same with reference to the accompanying
sheet of drawings of which Fig. 1 is a vertical section of my improved form of
filter shown mounted upon a pipe in a tank or reservoir after the manner fully
illustrated in the specification accompanying my aforesaid Letters Patent No 783184
and N° 163264 As shown by the drawings the filter consists of three concen-
trically arranged pervious cylinders A. B. and C. The central cylinder A. rises
above the level of the water in the tank or reservoir K. and consists of a perforated
or pervious pipe which is firmly secured to the sole plate D. which sole plate is
formed with a hollow conical faucet E. which fits and rests upon a similarly coned
and hollow spigot or branch F. which projects from the pipe G. The joint between
the faucet E. and spigot F. is packed by a rubber ring f. The cylinder A. may be
closed at the top by a lid as shown in dotted lines to protect the cylinder A. from
the possibility of being flooded. The said pipe G. is in communication with a
range, section or series of submerged filter units spaced at proper distances apart
and each similar in construction to the example shown. The inner cylinder A. is
surrounded by the second pervious cylinder B. which is strengthened by an angle
iron ring at the foot and rests upon the sole plate D, exact concentricity with
the cylinder A. being secured by a guide flange H. formed on or secured to the
sole plate. The cylinder B. is made tapered or conical in form and is of greater

page_text: diameter at the foot than it is at the top. The said cylinder B. is in its turn sur-
rounded by an outer pervious cylinder C. which is tapered similarly to the
cylinder B. and strengthened and mounted in the same manner.
It will be seen
that when the three pervious cylinders are in position two annular spaces are
left, the first I. between the cylinder A. and B. and the second J. between the
cylinders B. and C. The said annular spaces are filled with filtering material
which may either be uniform in consistency or may be of different natures or
of different degrees of fineness in accordance with the liquid to be filtered or the
purity required. When it is considered desirable to make the said filter beds of
different degrees of density I may charge the inner space I. with a combination of
'wood charcoal or carbonised saw dust with powdered animal charcoal. The said
animal charcoal may be the refuse or fine dust charcoal which is separated from the
granular charcoal when preparing it for the use of sugar refiners or such animal
charcoal may be otherwise derived or especially prepared for my purpose. The
wood and animal charcoal may be mixed in the proper proportions with water and
poured into the space I. and allowed to settle by drainage. The granules of wood
charcoal become coated with the animal charcoal or otherwise the latter is retained
within the interstices of the former and I obtain a filtering medium, which combines
the porousity of the vegetable charcoal with the purifying effects of the animal
charcoal. When animal charcoal is used I may enclose the central cylinder in
an envelope of flannel or other porous tissue or fabric which prevents the fine
powder from passing out along with the filtered liquid. The annular space J.
between the cylinders B. and C. is filled with a coarser filtering medium
such as wood shavings or saw dust the latter being either raw or carbonised.
When the filter is in use the water passes first through the outer filtering medium
in the space J. and deposits therein the grosser impurities. The partly filtered
water then percolates through the inner medium in the space I. which completes
the filtration and renders the effluent water clear and limpid. When animal
charcoal is employed the water is purified from organic matters and rendered more
fit for human consumption. In the former part of this description I have referred
to the cylinders B. and C. as being independently bedded on the sole plate D. and
of a greater diameter at the bottom than at the top. The object of this construction
and arrangement of the cylinders is chiefly to facilitate the easy and separate
removal of the filtering material in the spaces I. and J. For example when using
filtering beds of different material such as an outer filter bed of shavings or
sawdust and an inner filter bed of combined vegetable and animal charcoal, it will
be found that the outer coarser filter bed J. becomes quickly impure whilst the
more costly inner bed I. is still fit for use. In such a case I renew the outer
bed J. without disturbing the inner bed. To effect this renewal it is first
necessary to remove the filter from the tank or reservoir K. In order that no
unfiltered water may find its way into the pipe G. and to enable me in the case
of a group of filters to remove any filter unit without interrupting the working
of the others, I introduce a plug L. into the conical mouth of the spigot seating
or branch F. which plug L. may be introduced and withdrawn by means of a
rod M, or of a chain. When the water in the tank K. has thus been cut off from
the pipe G. the filter is slung and lifted by means of the eyes M. on the central
cylinder A. The means for removing and replacing the filter units may be
similar to those described with reference to my said foregoing patents or I may
employ a carriage mounted to travel on rails upon the top of the tank or
reservoir K. the said carriage having an aperture in its central part into which
the filter is elevated and in which it is retained and steadied during removal.
The filter is afterwards set down in any suitable place and the outer cylinder C.
is lifted away from the sole plate D. as shown in Fig. 2 of the drawings leaving
the filter bed J. free to be removed, after which the cylinder C. is replaced and
fresh filtering material is introduced after which the filter may be again lifted by
the central cylinder and replaced on its seating in the tank K. When it is
considered that the inner filter bed I. requires also to be renewed the cylinder B.

page_text: is slung and removed as already described with reference to the cylinder C. and
as shown at Fig. 3 of the drawings which shows the cylinder B. partly lifted
and exposing the central cylinder A. The filtering material I. may be washed
and returned to the cylinder B. or fresh filtering material may be introduced.
In a modified form of filter I fix the outer cylinder C. to the sole plate D. and
taper the cylinder B. in an opposite direction to that shown in the drawings. In
such an instance the cylinder B. and its filter bed would be first removed together
with the inner tube leaving the outer filter bed to be discharged in any suitable
manner. By a further modification the cylinder B. might be attached to the sole
plate D. in which case the cylinder A. would taper inwards from the top and rest
upon a rubber or other packed joint on the sole plate D. similarly to one of the
methods shown in my aforesaid previous Specification N° 1632634 Instead of
making the cylinders tapered as shown and described in the present specification,
I might make the sides of the cylinders to open and close like doors or I might hinge
the halves of the cylinders at the top and move them apart to discharge the filtering
material or I might make the cylinders in separable parts or arrange them to slide
telescopically after the various arrangements shown fully in my herein before
referred to Letters Patent. In many cases and especially where mechanical
filtration alone is required I dispense with the use of animal charcoal and charge
the inner space with a finer grade of filtering material than that contained in the
outer space or the two spaces may be charged with the same material. Although
I have shown and described my improved filter as having two filter beds, I wish
it to be understood that I may use more than two beds of filtering material.
I do not confine myself to the vertical position of the filters constructed as
herein before described nor to their use as low pressure filters as I may enclose
them in cases or chambers into which the water to be filtered is admitted at a
pressure above the atmospheric pressure suitable cocks or valves being provided
in lieu of the conical plug L. The pipe G. for leading away the filtered water
may be attached to the suction branch of a pump.
I do not confine myself to the cylindrical formation of the filters.
The combined animal and vegetable charcoal hereinbefore described may be used
in filters not having duplex or multiple filter beds or in filters differently con-
structed from the examples described or referred to in the present specification.
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. In filtering apparatus consisting either of one filter or of a group or series of
filtering units submerged in a tank or reservoir and each mounted upon a hollow
conical spigot branch or its equivalent communicating with a pipe or chamber
which receives the filtered water, constructing such filter unit or units with two or
more thicknesses or beds of filtering material of different or of similar natures and
separated by pervious concentric tapered cylinders or pervious cylinders or cases
capable of being opened or manipulated so as readily to release the contained
filtering material and arranged so as to be capable of easy and separate removal
substantially as and for the purposes herein before described and shown.
2. The combination of animal and vegetable charcoal to form a purifying and
filtering medium for the purposes and substantially as hereinbefore described.