Improvements in Filter Presses.
Year: 1886

page_text: Date of Application, 2nd Sept., 1886.
Complete Left, 31st May, 1887.
Complete Accepted, 1st July, 1887.
PROVISIONAL SPECIFICATION.
Improvements in Filter Presses.
I, JOHN WILLIAMSON, of St. Vincent Street, Glasgow, in the County of Lanark,
Chemical Engineer, do hereby declare the nature of this invention to be as
follows:-
This Invention which relates to improvements in filter presses has for object to
obtain more rapid and thorough lixiviation of the cakes formed between the plates in
using such presses, to obtain the washings of as high a density as possible, and to
provide means for separating the liquor which runs foul from that which runs clear.
I form upon each plate of the filter-press, at or near the lower side, a projecting
snug or piece, through which I bore or core two holes in such position that when the
plates are fitted together in the press these holes form two continuous but separate
longitudinal water ways or channels. In each of the alternate plates of the press
form a passage or port to connect the filter-space of the plate with one of the longi-
tudinal water-ways and in each of the other series of alternate plates, I in a similar
manner form passages or ports connecting the filter-spaces of these plates with the
second longitudinal water way. The two longitudinal channels for the wash liquor
begin from the bottom of the stationary head of the press and terminate at the shifting
head in two vertical channels or in pipes outside thereof extending to the upper side
or top of said plate, or vice versa, so that, the wash water may be led into the press
by the bottom of the shifting head and drawn off from the top of the stationary head.
The water whilst entering the plates of the press at the bottom may however be led in
at the top of the head through a channel cored vertically therein. Instead of taking
the wash liquor from the press by cocks provided for each plate as is usual, I draw off
the wash liquor from the top of either the stationary or the shifting head at the
opposite end of the press from that at which the wash water enters. I find in practice
that by so doing a great saving is effected, both in time and in the quantity of water
used and as a consequence the washings are of higher density; and when the wash
liquor is drawn from the opposite end from that at which it enters the distance the
wash liquor and the washings have got to travel in all cases is equal. In all other
filter-presses it is found that the cakes in proximity to the end where the water enters
get washed first. Consequently, those cakes have to be washed until the cake at the
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page_text: extreme end of the press is free from soluble matter. Under my invention however
if the washing liquor travels in a press six feet in length say only six inches, before
going through the cake, it has to travel five feet six inches, before it can escape. On
the other hand for the cake in the centre of the press, the wash liquor has to travel
three feet and after passing through such cake, it escapes into the washing channel
and travels other three feet before finally escaping. The wash water for the cake on
the extreme end of the press has to travel, say five feet six inches before passing
through the cake, but it has only six inches to travel after passing through the cake
before escaping from the press. Thus the combined distance that the water for
washing and the wash water has to travel being equal in all cases, the lixiviation is
thorough and complete in every cake.
I also form a snug or projection on the top corner of each plate, through which I
core or bore two holes in such position that when the plates are fitted together in the
press these holes form two continuous but separate longitudinal channels. In each
alternate plate I form a port or passage to connect one of these longitudinal channels
with the spaces between the filterplates and in each of the other alternate plates I form
similar ports or passages to connect the other longitudinal channel with the spaces
between the plates. By means of such an arrangement the air, as the wash liquor
enters by the bottom longitudinal channel, is forced out through the ports or passages
into the general air channels with which they are in communication.
Instead of forming one snug or projection at the top corner having two holes cored
or bored therein, I may make a snug or projection at each of the top corners of the
plate having one hole cored or bored in it and communicating by ports or passages
with the spaces between the plate in a manner similar to that described above.
It has been found in practical working that however close the interstices of the
cloth be woven, if the solid matter in the liquor to be filtered be of a fine nature, a
proportion of it always passes through the cloth when new cloths. are put on the plates
as also when they have been washed and when starting the presses. This liquor
which may be termed foul liqour, has no means of escaping unless by the cocks
provided for the filtered liquor and consequently it escapes from them into the gutter
used for the filtered liquor. In other cases it happens that through carelessness of the
workmen or by an accident or from some other cause a hole or holes may occur in
the filter cloth and escape observation, the press being meanwhile closed, screwed up
tight, and the liquor to be filtered forced into the press. It then happens that the
liquor from all the cocks runs clear with the exception of a few which run foul. In
order to allow the filtration in the press to be completed and prevent the foul liquor
which runs from any of the cocks mixing with the filtered liquor running into the
general gutter I attach a small auxiliary gutter to the main one and connected the
cock or cocks running foul liquor by a pipe, tube or rone, to this auxiliary gutter.
By this means 1 keep the filtered liquor clear of the foul and thus permit of the
completion of the filtration after being started.
Dated this First day of September 1886.

page_text: Improvements in Filter Presses.
I, JOHN WILLIAMSON of 65 West Regent Street, Glasgow, in the County of Lanark,
Chemical Engineer 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:-
My invention relates to improvements in filter presses and is illustrated by the
accompanying drawings in which figures 1 & 2 are elevations of two of the filter
plates of which the press is composed and figure 3 is a longitudinal section of part of
the press, the section being taken through the four plates marked A³, A2, A2, A2,
as at the centre thereof and through the stationary and shifting heads F, G, and two
front and back plates A1, A2, A2, A2 as at the line Z-Z in figure 5, which is an
elevation of the back or shifting end of the press whilst figure 4 is an elevation of the
front or stationary end of the press.
To obtain more rapid and thorough lixiviation of the cakes formed between the
plates in using such presses, and to obtain the washing of as high a density as possible,
I form upon each plate A' A', A2, A4, etc.; of the filter press, at or near the lower
side a projecting snug or piece a, a', a², a³, etc.; through which I bore or core two
holes b and C,
in such a position that when the plates are fitted together in the press
these holes form two continuous but separate longitudinal waterways or channels.
In each of the alternate plates A, A2, A3 etc. a port d is formed, communicating
with the filter space on each side of the plate and the lower longitudinal channel c,
and in each of the alternate plates A', A³ etc. a similar port e is formed communicating
between the filter spaces on each side & the upper channel b. The two longitudinal
channels b and c begin from the bottom of the stationary head F and terminate at the
shifting head G, in two vertical channels 6¹ and c¹ or in pipes outside thereof
extending to the upper side or top of the press.
A pipe for the conduction of the wash water is attached to a connecting piece p,
and by means of valves m and n the water is admitted through either of the channels
b, c, whilst the other channel serves for the outlet of the sweet water, the lixiviation
being conducted by preference by using the channels b, b', and c¹ alternately for
C,
the admission of the wash water, the water entering the channel 6, 6' passing through
the series of ports e in the plates A¹ A³ etc. into the filter spaces through the cakes
or sludge formed therein and displacing the air, which is driven off through ports
h, k and channels f, g, at the top of the plates, and after passing through the cakes or
sludge the wash water passes out by the ports d in the plates A, A, A' &c. to the
channels c, c, and escapes by the valve q into the small gutter S and thence into the
main gutter T of the press.
In the alternate course of admitting the wash water into the channel c, c¹, the
sweet water passes into the channel b, 61, and escapes by the roner into the above
mentioned receptacles. By thus drawing off the sweet water at the opposite end of
the press to that at which the wash water enters, a great saving is effected, both in

page_text: time of operation and in the quantity of water used, since the total distance which is
traversed by the wash water and sweet water used and produced in the lixiviation of
each cake is in all cases equal. In all other filterpresses it is found that the cakes
nearest the point where the water enters are lixiviated first, and as a consequence,
when the cakes at the further end are only partially lixiviated those washed first are
running clear water and diluting the sweet water unnecessarily. In using the
improved press, however, every cake is washed simultaneously and therefore in less
time and with the employment of less water.
The air-outlets are formed by the ports h, k, and passages f, g, bored or cored in
the snugs or projections / formed on the top corner of the plates, or instead of having
the passage g below the passage f, it may be bored or cored in a snug or projection
on the other top corner of the plate as indicated by the dotted lines . The filter
plates are provided with the usual drain cocks i.
To the main gutter of the filter-press, I also affix a small auxiliary gutter t extending
the full length of the main gutter and provided with a separate outlet. This I employ
for the purpose of preventing foul liquor discharged by the drain cocks i, from mixing
with the pure and clear liquor which is allowed to run into the main gutter and is
utilized by bringing it into communication with any such cocks running foul by a
small bent pipe u, placed in the position indicated by the dotted lines in figure 4.
Instead of affixing an independent gutter I may make a partition in the main gutter
and utilize the small division thus formed as the auxiliary gutter, as indicated by the
dotted lines t¹, or I may form the auxiliary gutter within the main gutter as indicated
by the dotted lines t².
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. The combination of parts constituing the improved filter-press substantially as
herein described with reference to the drawings annexed.
2. In a filterpress, the improved filter plates having snugs or projections with
lixiviating channels such as b, c formed in them and ports e, d communicating between
the filter spaces and alternately with the upper and lower channel throughout the
series of plates, vertical inlet and outlet channels or pipes reaching to the top of the
press being provided, substantially as and for the purpose set forth.
3. In a filter press the arrangement of the continuous channels for lixiviating so
that the sweet water can be drawn off at the opposite end of the press to that at which
the wash water enters, substantially as described with reference to the annexed
drawings.
4. In a filter press the combination with the main gutter and drain cocks of an
auxiliary gutter and pipe connection to the drain cocks substantially as and for the
purpose set forth.
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