Improvements in Filtering Machinery.
Year: 1891

page_text: Date of Application, 10th Apr., 1891-Accepted, 8th Aug., 1891
COMPLETE SPECIFICATION.
Improvements in Filtering Machinery.
I EDGAR MARTIN of Hamper Mills near Watford in the County of Herts
Paper Maker 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 :-
This invention has for its object the filtering of water by means of a travelling
endless band of any material suitable for a filtering medium either separate or
combined with other materials and which is so arranged that a portion of its
length is made to assume the form of an open shallow cistern. For this purpose
the said endless band is so arranged and mounted that as it travels it is caused at a
certain point to make a slight descent and the two sides or edges are caused to turn
up. A portion of the length of the said band extends horizontally in this form
and is then caused to rise spread out and become flat. In this manner a shallow
cistern is formed for receiving therein the water to be filtered. The endless band
may be strengthened and supported by travelling belts or any other suitable
manner.
The liquid to be filtered flows on the upper surface of that portion of the endless
band which has thus been made to assume the form of a shallow open cistern filters
through it is collected underneath and conducted where required.
The said endless, band may be always travelling and the speed so regulated that
during the time it is passing over the distance where it assumes the form of a
cistern and acts as a filter it will become coated with matter (if any) arrested from
the liquid which has just been filtered. Continuing to travel the said endless band
is conducted through a cleansing apparatus and returns clean and again ready for
filtering to that point where it was first made to assume the form of a cistern and
act as a filter.
Thus the entire length of the endless band takes its turn (part at a time) in
assuming the form of an open shallow cistern acting as a filter and thereafter
passing through the cleansing apparatus so that the processes of filtering and
cleaning proceed without interruption; or filtering and cleaning may be conducted
intermittently if desired.
This arrangement may be used for upward filtration if desired.
Vacuum boxes (such as those used on the well known continuous paper making
machines) or other equivalent or suitable devices may-if desired-be used to
accelerate the filtration that is to draw the water through the endless band of
filtering material.
In carrying out this invention I employ an open shallow cistern tank or vessel
which may be made of iron or any substantial material and of square rectangular
or other suitable form.
The upper part of this fixed cistern is arranged to receive a series of rollers or
any suitable support for that portion of the endless band of filtering material
which acts as a filter and allows the same to travel and near or upon the top of the
said cistern there are fitted certain small rollers pulleys or other arrangements for
receiving the two turned up edges of the said filtering material and allowing and
assisting same to travel also.
In order to strengthen the said endless band of filtering material and facilitate
its travelling a small wire cord or tape may be attached to each of the two extreme
edges of the entire length of the said endless band and the small rollers or pulleys
last referred to may be grooved or otherwise formed on the periphery for receiving
and guiding the said wire cord or tape and along each side of the said endless band
and close to that part which turns up there may be fastened a strip of cotton

page_text: belting woven wire or any pliable material and similar strips may be fastened to
the said endless band parallel with the edges at suitable distances from cach other
and continued the length of the endless band for the purpose of strengthening the
same when the width is considerable.
And in order that my present invention may be easily understood and readily
carried into practice I will proceed to more fully describe the same with reference
to the drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a longitudinal sectional elevation of apparatus arranged and acting
in accordance with my present invention.
Figure 2 is a longitudinal elevation of same machine.
Figure 3 is a plan of Figures 1 and 2.
Figure 4 is a cross section of the apparatus on line 1-1 Figure 3-but with the
addition of the "vacuum boxes" hereinafter described.
Figure 5 is a part side sectional elevation showing the "
applied.
vacuum boxes
:-
"
Figures 6, 7 and 8 are enlarged detail views of particular parts
Figure 6 being a local enlarged view of the rollers bb× 61 and 62 and the
pulley c.
Figure 7 is a side view taken on the line 2-2 of Figure 6 to show how each
edge of the endless band of filtering material is turned up as it enters the
machine to form the shallow cistern or hollow to receive the water to be filtered.
Figure 8 is an edge view of the wheel or pulley which assists to so turn up
the said edge.
a is an open cistern tank or vessel (of wood or metal or any other suitable
material) supported on girders a¹ which rest on columns a².
A series of rollers extends across the cistern a for the purpose of supporting
the band of filtering material and along the top edge of each side of the cistern
there are small rollers or pulleys for receiving the two edges of the filtering
material.
The pulleys
cc are mounted on shaft e¹ supported by brackets c² bolted to the
side of the cistern a.
These pulleyse press the endless band on to the underneath rollers or where
"vacuum boxes" are used then these drums or rollers e press the endless band of
filtering material on to independent small rollers * see Figure 6. Another pulley
or roller 2 presses on the small roller or pulley b'.
dd is the endless band of filtering material having attached at each edge d¹¹ a
Hexible wire cord (tape or any strong pliable material) e and at d² there is a strip
of pliable material such as cotton belting or woven wire. The endless band of
filtering material enters the cistern say at the right hand end (in the direction
shown by the arrows Figures 1 and 2) and passes between the pulleys cc and the
rollers whilst the top edges with flexible wire cord e therein travel along
between the small rollers and 22. The strips d' are of too close a texture
to allow water to filter through and therefore the impurities of the water are not
pressed through the filtering material into the lower part of the cistern when
passing between the said pulleys and rollers.
In some cases the strip may if desired be of sufficient width to extend up the
side and have the wire or cord attached to the top of it.
dis an additional strengthening strip clipped between additional drums or
pulleys ex and the rollers . Such additional strips and additional pulleys may be
employed to any extent found necessary according to the size of the filter.
is the wheel or drum one of which is mounted each side at the front of the
machine to assist to turn up the edge of the endless band d.
A groove a is formed on the outer edge of a in which groove a' the wire cord e
on the edge d lies while the inner face of each such drum a slants towards the
other (see Figure 3 and also Figure 8).
:

page_text: Thus as the endless band & returns from the cleaning apparatus and rises up
(when it is returned underneath) to the front end of the tank or cistern a-the
extreme edge thereof containing the wire cord e is guided into the groove a while
the edge d' lics closely against the face of the drum and the middle part of
the band d lies against the roller r³ and in this manner or in any other equivalent
or suitable manner the edge at each side of the endless band d is turned up.
At the opposite end there are suitable drums or pulleys and rollers where
the endless band of filtering material is caused to rise a little and then spread
out flat.
The endless band d in such flat state is then brushed and passed between rollers
as illustrated in Figures 1 & 2 of the drawings or it may be cleaned or treated in
any other convenient or suitable manner and thereafter steamed if desired.
Such steaming will be found to be a great advantage as it not only destroys
all organic matter, thus purifying the filtering material, but tends to preserve the
latter.
The steaming may be effected (as often as required-say once or twice a week)
in any suitable manner and this can easily be effected at some convenient point of
its travel-but I make no claim to such steaming inasmuch as I am fully aware
that steam has already been applied in other forms of filtering apparatus.
The pulleys c and c* are arranged so that they press upon the filtering material
where it has been strengthened in the manner already described. There may be
more than two pulleys c upon each shaft c¹ extending across the face of the endless
band d so as to press upon and grip said endless band d wherever strips of
strengthening material such as d have been attached to it.
The speed at which the filtering material travels is intended to be regulated
according to the impurity in the liquid to be filtered so that whilst travelling from
one end of the shallow cistern a to the other it becomes more or less coated or
choked with matter arrested and therefore useless for filtering until it has been
cleaned.
The liquid to be filtered should not be allowed to fall upon the face of the
filtering material in a heavy stream lest the impurities be driven through the
material instead of remaining in same or on the surface thereof. To avoid this a
"distributor" may be employed consisting of a shallow cistern or tray fixed
immediately above the filtering material and supplied from the water supply pipe f
down a channel. In the bottom of the said tray there is a series of very
narrow slits f. The liquid to be filtered is delivered into this tray and escapes
through the narrow slits and falls on the filtering material in a series of small
streams. Should large particles of suspended matter tend to choke the slits ³
they are readily cleared by drawing a brush or scraper over them. In the case of
river water largely charged with floating pieces, such pieces would be arrested by
the distributor and can be removed automatically by a travelling brush or scraper,
or in any other suitable way.
For filtering muddy water such as is frequently obtained from rivers and streams
this form of filter is particularly well adapted. According to the finely divided
state of the matter in suspension in the water to be filtered so the filtering material
can be of any degree of fineness that may be found necessary to arrest it. The
result will be that the filtering material will choke very rapidly but this is readily
counteracted by causing the filtering material to travel faster with the result that
every part is more frequently cleaned.
The before mentioned vacuum boxes are arranged and act as follows (see
Figures 4, 5, 6 & 7) :-
:-
Division pieces gg' are placed in the cistern, or tank a the bottom of such division
pieces gresting upon the bottom of the cistern a whilst the top face comes in
close contact with the filtering material d which will consequently while travelling
touch upon the top of such division pieces g g'. By providing each division h
with a separate outlet underneath and either attaching such outlet to a pump or
conducting the said outlet pipe downwards and giving it a considerable fall

page_text: (say 5 to 10 feet) a partial vacuum can be obtained which will draw the water
through the filtering material d with a similar effect as though there were
corresponding head of water above it.
a
By such an arrangement I have estimated that very muddy river water may be
passed through the endless band of filtering material at a rate of more than
100 gallons per square foot per hour and the resulting filtered water will be bright
and of better quality than can be obtained from ordinary sand beds filtering at
their usual speed of 2 to 3 gallons per square foot per hour.
The aforesaid vacuum boxes" may or may not be used for other descriptions of
water whether of a more or less impure state.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I would remark that
I am aware that in machinery for filtering water it has been proposed to use a
travelling endless band of filtering material which is caused to descend at one part
of its travel and again ascend further on its travel and I make no separate claim
thereto whatever but what I do claim is :-
By the means and in the manner hereinbefore described to turn up the outer
edges of the part between the points of such descent and ascent whilst the said
endless band travels along-so that a portion of the band itself forms a shallow
cistern to receive the water to be filtered whilst when that part of the band is not
actually filtering, it is flat in form cross wise and capable of ready and rapid
cleansing.
Dated this 10th day of April 1891.
TONGUE & BIRKBECK,
34, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Patentee.