IMPROVEMENTS IN FILTERS
Year: 1875

page_text: PROVISIONAL SPECIFICATION left by Benjamin Hardwick Foster at
the Office of the Commissioners of Patents, with his Petition, on
the 22nd October 1875.
I, BENJAMIN HARDWICK FOSTER, of Newcastle-on-Tync, in the
County of Northumberland, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN FILTERS," to be as follows:-
This Invention consists of improved methods of constructing and
arranging the parts of filters used for the purpose of separating
impuritics from water or other fluids, by which improved methods the
apparatus is more effective in its operation and is more casily cleansed
than in filters as ordinarily constructed and used.
I arrange a vessel of suitable shape and size, preferably circular or
square in plan, and of carthenware or other convenient material, but
preferably of cast iron enamelled inside, which may be made ornamental in
appearance. At the lower edge of this vessel or at a convenient distance
from it I form a horizontal bottom, and above the level of this bottom
but outside the vessel I form or fix a chamber containing two or three
stop cocks or taps constructed in the manner herein-after described.

page_text: The water to De filtered is admitted into this chamber through a main
supply pipe, and it then passes into the vessel through one of the stop
cocks above the horizontal bottom described, but below a moveable
horizontal perforated plate of carthenware or other suitable material,
which is arranged in the vessel at a suitable distance above the hori-
zontal bottom plate, the space between the two being filled with sponge
or other coarse porous material. Near the top of the vessel is arranged
another horizontal perforated plate, and the space between this plate
and the lower one is filled with powdered animal charcoal or other
suitable filtering medium, through which the water rises and passes
through the upper perforated plate into the space above the latter,
whence it can be drawn off through a pipe open at its upper end, which
passes down through the two perforated plates and the powdered
charcoal, and is connected with the stop cock by which its flow is
regulated. The stop cock is made with two separate transverse passages
through it, one above the other; the lower passage admits the unfiltered
water from the chamber to the sponge, whilst the upper one com-
municates between the lower end of the pipe described and the discharge
orifice for the filtered water. When this cock is closed by turning its
plug in the usual way, its upper passage then opens a communication
from the supply chamber to the second stop cock, whilst its lower or
discharge passage is closed.
In order to cleanse the filter another pipe is arranged open at its
upper end which communicates with the space above the upper
perforated plate, whilst its lower end communicates with another stop
cock arranged in the chamber first described. This second stop cock is
constructed also with two passages through it, one above the other; its
upper passage communicates (through the first stop cock) with the
supply pipe on one side, and the lower end of the pipe last described on
the other side; its lower passage communicates between the space
containing the sponge (as above described) and a discharge opening.
If the second stop cock therefore be opened (the one first described
being closed) water passes directly to the top of the filter and passes
down through the two perforated plates, the powdered charcoal and the
sponge, and is then discharged, carrying with it the impurities which
have collected in the filter.
The two stop cocks constructed as described may be connected
together by lovers or whools and endless cover in such manns

page_text: when one is opened the other is closed, and vice versâ, or so that both
are closed. A third stop cock may be fitted to the chamber for the
purpose of drawing off unfiltered water from it. The perforated plates
described may be made of earthenware, glass, gutta percha, or fire-clay,
to suit different circumstances, and sometimes instead of arranging the
apparatus vertically as above described I arrange it horizontally, the
chamber for the stop cock and the admission of the water being at the
end instead of the side of the vessel. This form of arrangement is more
especially applicable to waterworks and large factories.