Improvements in or connected with Filters.
Year: 1895

page_text: .Date of Application, 31st Aug., 1895-Accepted, 5th Oct., 1895
Improvements in or connected with Filters.
I, JOHANN FRIEDRICH FISCHER, of Worms, in the Empire of Germany,
Director of Corporation Water Works at Worms, 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:-
"
Hollow filter bodies of filters hitherto used for filtering liquids, have been mostly
made in this way-Two filtering plates have been joined together, and between
them a suitable insertion has been used to make a tight joint. This mode of
making the hollow filter bodies is, however, ineffective, inasmuch as it has not
been possible to make the insertion joint sufficiently good, as to stand and suit the
conditions under which filters of this type are worked; and moreover, too much
time is required in joining the several plates forming one filtering body together.
According to this invention, the hollow filtering bodies are manufactured in a
single piece; and is found to be very advantageous to do so instead of joining them
together out of several pieces.
The hollow filtering bodies are made as follows:-
A mixture of washed sharp sand and powdered glass ground or reduced,
preferably, to a very fine state-which materials, according to the purposes of the
filtering bodies, will be used in the proportion of one to one, to three to two-is
placed in a chamber of a suitable furnace, such as an earthenware or chinaware
burning kiln, in a dry or moistened state in a suitable mould, such as of suitable
fire-brick, in a horizontal or vertical position, and in this furnace it (the filtering
body) is subjected to and burnt at a high temperature, such as 10000 or 1200° C.
The hollow space in the filtering body is either formed by means of a combustible
core, or some mixture or material that does not coalesce or cake by burning, but
can be readily removed after cooling.
The filtering parts or elements prepared in this manner are then tested with
regard to their resistance, as well as their capacity as regards quantity and quality
of work.
This invention has also partly reference to a special mode of construction of the
filter, in which the filtering bodies, as above described, are advantageously employed
for the filtration of water.
Referring to the drawings which illustrate this invention, Figure 1 shews such
an apparatus in longitudinal section; and Figure 2 shews a cross section through
the apparatus.
Referring to the drawings, hollow filtering bodies are placed in a vessel a, into
which the liquid to be filtered is introduced through a pipe c.
The filtering bodies are so arranged that they are placed in pairs vertically, one
above the other, their inner spaces or chambers being connected with each other
by pipes d.
The liquid enters from the outside through the walls of the filtering bodies
into the chambers h, and in so doing deposits its inpurities in the pores of the
walls; thence the purified liquid is carried, by means of the pipe g, which connects
all the upper bodies into a reservoir, or direct to the place of use, through the
cock s.
The pipe g (which collects all the filtered liquid), moreover, has the object
being fixed at the highest point of the filtering elenients-of carrying off air
eliminated by the filtration, together with the filtered liquid. In the cock or

page_text: valve s there is a metal plate with an opening, which, when the level of the water
in the vessel a is kept constant allows a uniform quantity of water of a certain
ratio to the filtering surface of the bodies, to pass through, whereby the quality of
the filtered liquid is considerably improved from a bacteriological point of view.
The size of course will have to be found in the first instance by direct experiment
in each case.
On the pipe g there is a glass tube r, acting as a water-level-gauge, with which
the water in the vessel a communicates so long as the capacity of the filter exceeds
the quantity of water which can flow out through the adjusted opening in the cock
or valve s.
As soon as the level in the water gauge is lower than the level in the vessel a,
the capacity of working of the filtering bodies is shewn to have been reduced. The
impurities which have settled in the pores of the filtering bodies are thereupon
removed by an opposite or backward flow of water through them, through closing
the valves and opening slide valve v, which is connected with the pure water
service; so that pure water is forced through the apparatus under pressure in
the opposite direction to that of the filtration, the water thus passing through
pipe g into the cavities h, and from there through the wall of the bodies into the
vessel a, whereby the dirt in the pores and on the outside of the filter bodies is
detached.
In the arrangement described, the filtering bodies are connected in pairs placed
vertically one above the other, for the purpose of saving space; but in the same
manner, one or more of such bodies above one another may be arranged,
accordingly as it is required by the extent of the installation, and the space at
disposal.
Between the filtering bodies placed one above the other, an india-rubber ring f
is placed round the tube d; which ring is compressed by the weight of the upper
body, and therefore serves to render the connection by the tubes d tight and
impermeable. The lower filtering bodies should be arranged on bricks, so as to
prevent their coming into direct contact with the base of the vessel and the mud.
In the arrangement described, the liquid to be filtered was brought into the
vessel a and thence into the cavities of the filtering bodies; but the arrangement
may also be made in such a manner that the liquid to be filtered is brought through
the pipe into the interior of the cavities, and thence through the walls into the
vessel a, whence the filtered liquid is then removed.
The filter herein described, comprising the filtering bodies made of sand and
glass, and burnt, form, together with the collecting tubes for carrying off the
filtered liquid, and their special connections with the bodies, a complete apparatus.
The body in itself, arranged in a filter as set forth and shewn unconnected with the
pipes, would not be so serviceable as a filter for working on a large scale, if it were
not for the fact that by connecting it with the pipes as described, it is rendered
possible of being cleaned, by driving the water in the opposite direction to that of
the water in being filtered.
This backward cleansing or rinsing, which has hitherto been incapable of being
efficiently performed on a large scale, on account of all attempts having proved
abortive, owing to the low power of resistance of the filtering material, is rendered
possible by reason of the filtering material now employed, which is able to stand
the greatest pressure desired.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
:-
1. The new or inproved filter body herein described, namely, a filter body
consisting of walls and an inner chamber, made without joint, i.e. in one piece, and
of sand and glass, burnt at a high temperature: for the purposes specified.
2. A filter comprising a series of hollow filtering bodies made without joint and
of sand or glass, burnt at a high temperature; a pipe connecting the upper parts

page_text: of said bodies together, through which the filtered water is conveyed away, and,
alternately, cleansing water supplied to them; a vessel in which said bodies are
disposed, in which the water to be filtered is contained; and suitable valves for
controlling the flow to and from the different parts; substantially as and for the
purposes set forth.
3. The herein described improved mode of filtering, consisting of the employment
within a vessel of one or more filtering bodies; and a pipe with a regulated outlet
thereon such as described, whereby, by employing a constant head of water to be
filtered, and the regulated outlet as described, a uniformly filtered liquid as regards
quantity and quality is produced.
4. The filter, with its filter bodies and connections, particularly as set forth with
reference to and shewn in the drawing.
Dated this 27th day of August 1895.
CHEESBROUGH & ROYSTON,
15 Water Street, Liverpool, Applicant's Patent Agents.