Year: 1886

page_text: [Communicated from abroad by WILLIAM MILLAR DEUTSOn, of Elizabeth, State of
New Jersey, United States of America, Manufacturer.]
I HENRY EDWARD NEWTON of the Office for Patents 6 Breams Buildings, Chancery
Lane in the County of Middlesex Civil 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:-
11
This invention relates to that general class of filters in which the purifying or
cleansing of the water is accomplished by causing the water to percolate through a
body of granular material and particularly to a filter of this class which is designed
for filtering water in large quantities as for supplying cities and factories.
One feature of the invention relates particularly to a means for introducing a
substance into the water before its passage through the filter bed whereby the
impurities contained in the water are accumulated and precipitated to such an extent
as to be more readily caught up and arrested by the granular material forming the
filtering bed. In filtering water by means of a bed of granular material it has been
found that in many cases the impurities contained in the water are so fine or of such
a nature that they cannot be entirely removed from the water by passing it through
the bed unless the bed is made of such fine material and of so great a thickness that
considerable time will be required for the water to pass through it, thus making the
filtering operation exceedingly slow and rendering it practically impossible to carry
on filtration upon an extensive scale. It has been found, however that in such cases
the operation may be greatly expedited and all the finer impurities in the water be
brought into such condition that they will be readily arrested by the bed, by intro-
ducing into the water previous to its passage through the bed, some precipitating
substance by which the impurities will be accumulated so as to be readily arrested by
the granular material of the bed even if such material is comparatively coarse so as to
permit the water to flow rapidly through it. The substances which are suitable for
use for this purpose are well known to those familiar with this art and need not be.
n

page_text: herein specifically described. Among these substances those which are most commonly
employed are alum, iron and lime in different forms. One feature of the present
invention, as before stated, relates particularly to an apparatus for introducing any of
these substances into the water before it arrives at the filtering bed.
In using filters of this class particularly where the water filtered contains a con-
siderable quantity of impurities it is of course necessary from time to time to cleanse
the body of filtering material or filtering bed as otherwise the continued accumulation
in the bed of the impurities removed from the water would prevent the passage of the
water through the bed and thus render the filter inoperative. This cleansing of the
bed has usually been accomplished either by forcing the water through the filter in
the reverse direction so that the impurities lodged in the bed during the filtering
operation were carried upward out of the hed by the reverse current and conveyed
away through a waste pipe or by removing the bed from the filter and replacing it
with a new bed of clean material or washing it in any suitable manner and then
replacing it.
The first of these methods of cleansing the fitering bed has been found objectionable
in practice because of the large amount of water consumed in the cleansing operation
which water in most cases amounted to from one to six per cent of all the water
filtered and which, of course, was entirely wasted.
The second method of cleansing the filtering bed has also been found objectionable
in practice not only because of the time consumed in removing and replacing the bed
but because of the considerable labor involved in that operation.
In the filters of this class, as ordinarily constructed the water after passing through
the bed of granular material enters the discharge pipe of the filter either through
perforations formed in the end of the pipe or in a plate or diaphragm located in the
bottom of the filter, the purpose of the perforations being to prevent the granular
material of the bed from being carried into the discharge pipe. This arrangement has
not, however, proved entirely successful. If the perforations were made sufficiently
small to arrest the smaller particles of the bed and prevent them from passing into the
discharge pipe, then they were liable to become clogged so as to prevent the free
entrance of the water into the pipe; while on the other hand if the perforations were
made sufficiently large to prevent liability of clogging they would permit the passage
of some of the smaller particles of the bed and thus some portion of the bed would be
carried into the discharge pipe and either clog the pipe or be delivered with the filtered
water.
Various expedients have been resorted to to obviate this difficulty none of which,
however, have proved entirely satisfactory in practice.
Another feature of the invention consists particularly in the apparatus for washing
the filtering bed.
As a full understanding of the invention can be best imparted by a detailed
description of a filter embodying the same, all preliminary description will be omitted
and a full description given, reference being had to the accompanying drawings in
which
--
Fig. 1 is a sectional elevation of a filter constructed according to the present
invention.
of Fig. 1.
of Fig. 1.
the washing pipes.
of Fig. 4.
Fig. 2 is a horizontal section of the same taken on the line
Fig. 3 is a horizontal section of the same, taken on the line
Fig. 4 is an enlarged view of a part of Fig. I showing one of
Fig. 5 is a vertical section of the same, taken on the line
Fig. 6 is an enlarged horizontal section, showing the construction of the pipes
through which the water is discharged from the filter.
Fig. 7 is a vertical section taken on the line of Fig. 6.
Fig. 8 is a cross-section taken on the line of the same Figure.
Fig. 9 is a side elevation partly in section upon an enlarged scale of the apparatus
for introducing the percipitating substance into the water.
Fig. 10 is a plan view of the same.
Fig. 11 is a horizontal section of the same taken on the line .c .c of Fig. 9.

page_text: Fig. 12 is a sectional olevation upon the same scale as Figs. 1 and 2 illustrating a
modified arrangement of the apparatus for introducing the percipitating substance into
the water.
Figs. 13 and 14 are views illustrating modifications in the construction of the said
apparatus which will be hereinafter referred to, and
Fig. 15 is a view similar to Fig. 3 but upon an enlarged scale, illustrating a modified
construction and arrangement of the discharge pipes.
The
Referring to said drawings it is to be understood that the body A of the filter or
what will be termed the filter is of any of the usual forms. As herein shown it is of
cylindrical form and of a height equal to about twice its diameter, but it may be of
any other form and of other proportions to suit the location in which it is to be used.
The filter, as herein shown, is closed at its top but if the top of the filter is located
above the level of the source from which the water is drawn it may be open.
filter is connected at a point near its top with the induction pipe B through which the
water enters the filter and is also provided near its top with a waste pipe C, the purpose
of which will be hereinafter explained. The filter as shown in the present case is
provided with two vertical partitions a which extend from its bottom upward about
one half of its height and thus divide the bottom portion of the filter into four
compartments, 2. 3. 4. 5 as shown in Fig. 3.
The discharge pipe D through which the water passes after being filtered is provided
with four branches d which enter the filter at its bottom and lie horizontally on the
bottoms of the compartments 2. 3. 4. 5, extending to points near the centre of the
filtre, as also shown in Fig. 3. The branches d are provided inside the filter with a
number of smaller lateral Branches e which extend horizontally along the bottoms of the
compartments 2. 3. 4. 5 and these branches and also the portions of the pipes d which
lie inside the filter are perforated, as shown in Figs. 6. 7 and 8.
The branches e and also the perforated portions of the branches d are surrounded by
pipes e which are of considerably larger size and all also perforated. The spaces
thus formed between the pipes ad and the enclosing pipes e bare filled with a coarse
granular material such as fine gravel or pebbles, as shown in Fig. 8. The purpose
of this construction and arrangement will be made clear when the operation of the
filter is explained. The gravel is not shown in Figs. 6 and 7 because the showing
of it in these figures would tend to obscure the other parts.
The induction pipe B is connected to the discharge pipe D outside the filter by a
vertical pipe E which is provided with two lateral branches. The branch which
is the upper one of the two, is provided with a number of branches & which extend
either upward or downward (upward as shown) outside the filter and then bend and
enter and extend horizontally into the filter at about two thirds its height. The branch h
which is the lower one of the two is also provided with a number of branches i which
are arranged similar to the branches and extend horizontally into the filter at right
angles to the pipe k and at about one third its height.
The portions of the pipes which lie inside the filter are perforated, as shown in
Fig. 4 and each of the pipes is provided at its inner end with a vertical branch G
which extends upward to a point just above the surface of the bed and is open at its
upper end as shown in Figs. 1, 4 and 5. Each of the pipes ik is provided with a
valve or gate 7 which controls the opening of its branch 6 and is provided with an
operating rod S which extends the length of the pipe, as best shown in Fig. 4, and
passes outward through a stuffing box where it is provided with an operating handle 9.
The pipes ik are supported upon suitable tie-rods 10 which extend horizontally across
the filter as shown. The filter is also provided with suitable hand holes as 11, 12, 13
through which access can be had to its interior at various points.
The several pipes hereinbefore described are provided with valves or gates arranged
as follows:-The induction pipe B is provided with valves 16-17 located respectively
upon the opposite sides of its connection with the pipe E. The pipe E is provided
with valves 18-19 located respectively above and below its connection with the
pipes h. The discharge pipe D is provided with a valve 21 located outside its
connection with the pipe E. The pipes d are provided with valves 20 located outside

page_text: the filter. The pipes are provided with valves 14 and the pipes with valves 15
located outside the filter; and the waste pipe C is provided with a valve 22. The
purpose of these several valves or gates will be made clear when the operation of the
filter is explained.
The filtering bed F which is composed of any suitable granular material is placed
in the bottom of the filter and fills the compartments 2. 3. 4. 5 and the filter to a point
about three or four inches above the pipes and slightly below the upper ends of the
vertical pipes 6, as indicated in Fig. 1.
The operation of the filter thus constructed is as follows When the filter is in
ordinary operation the valves 16-17 and 20-21 will be opened and the valves 14-15
18-19 and 22 will be closed. The water will then enter the filter through the induc-
tion pipe Band will percolate downward through the filtering bed F depositing its
impurities therein and will then pass through the perforations in the pipes e. b thence
through the granular material surrounding the pipes c. d and through the perforations
in said last pipes, and will then be discharged through the branches d. and discharge
pipe D. During this operation some of the finer particles of the granular material of
which the bed is composed will be carried through the perforations in the pipes el but
any portions of the filtering material which are thus carried into the pipes e. b will be
lodged in the interstices among the granular material fand be prevented from being
carried through the perforations in the pipes cd. and into the discharge pipe.
per
It has been found in practice that in using a filter of this character the greater
portion of the impurities contained in the water is lodged in the upper portion of the
bed. That is to say, if the water percolates through the bed simply by gravity, as
when the filter is located on or nearly on a level with the source from which the
water is drawn, the impurities will be mostly deposited in the first inch or two of the
filtering material at the top of the bed, while if the water is under pressure the
impurities will be mostly deposited within from two to eight or ten inches of the top
of the bed, depending upon the pressure to which the water is subjected. From this
it will be seen that in any case the upper portion of the bed becomes foul and requires
cleansing much more frequently than the lower portions of the bed. When, however,
us has heretofore been customary, the cleansing of the bed is accomplished by sending
a reverse current of water through the discharge pipe, it is evident that the whole
bed including the lower and comparatively clean portion, must be washed each time it
becomes necessary to clean the upper and foul portion of the bed. This frequent
washing of the whole bed not only, as before stated consumes a considerable amount
of time but also consumes a large amount of water, usually from one to six cent
of all the water filtered, which water goes to waste and thus makes the washing of
the bed expensive, particularly where the water is supplied by pumping. By the
construction shown in the present case this is largely avoided. After the filter has
been in use for a time and the top of the bed has become so foul as to need cleaning,
the valves 16 and 20 are closed and the valves 19-14 and 22 opened. The filtered
water is then forced or allowed to flow back through the pipe D'and up through the
pipe E and into the pipes k. where it will issue through the perforations in said
pipes k. and pass upward through the small amount of the bed above those pipes.
The upward currents thus formed will agitate the upper part of the bed and carry up
out of the granular filtering material all the impurities accumulated therein, which
impurities being lighter than the material of the bed will be carried to the top of the
filter and out through the waste pipe C. By this means the top of the bed which
contains the greater part of the impurities taken from the water being filtered will be
cleansed in a few minutes and by the use of only a small amount of water. Any
particles of the granular material of the bed which may have passed through the
perforations in the pipes k. during the filtering process may be removed from these
pipes by opening the valves 7. and turning the rods 8. which as will be observed are
square, so as to lessen the particles of the filtering material in the pipes. The water
admitted to the pipes at the commencement of the washing operation will then drive
such accumulated particles up through the vertical pipes 6. and deposit them on the
top of the bed F after which the valves 7 will be closed. After the top of the bed has

page_text: been thus washed the valves 22-14 and 19 will be closed and the valves 16 and 20
opened and the filtering proceeded with. The operation just described will be repeated
as often as may be necessary. After the filter has been in use for some tinic the
bed will become foul to a greater depth than the pipes k. When this takes place the
washing operation just described will be repeated except that the valves 15 instead of
the valves 14 will be opened so as to allow the washing water to enter the pipes i.
By this means the bed may be cleaned down to the level of the pipes i. The pipes i
may be freed of any particles of the granular filtering material which may have been
carried into them through their perforations by opening the valves 7. the same as
already described in connection with the pipes k.
It will be observed not only that the washing pipes k. i. are straight pipes, but that
each one of them is arranged to receive its washing water independent of the others.
By making these pipes straight the valve rods 8. are allowed to extend the length of
the pipes, as shewn, and thus by making the rods Square, a means is afforded for
loosening the granular material of the bed which will accumulate and pack in the
pipes i during the filtering operation so as to allow it to be driven out by the washing
water. By arranging the connection so that the washing pipes are supplied with
water independent of each other a practically uniform pressure is obtained in all of
the pipes, which would not be the case if the several pipes of each series were
connected together so as to form one continuous pipe.
After the bed has been for a long time in use, say several days under ordinary
circumstances, the whole bed will require cleaning, and when this occurs the washing
may be effected by closing the valve 16. and opening the valve 22. The water sent
in the reverse direction through the pipe D will then pass into the pipes d. c. and
issue through the perforations in these pipes and after passing through the gravel f.
issue through the perforations in the pipes b.e and pass upward through the bed.
the water passes out through the gravel f. it will agitate the gravel, which, as will be
observed (see fig. 8) does not quite fill the spaces between the pipes c. d and the
pipes b. e and thus carry any particles of the granular material of the bed which may
have passed through the perforations in the outer pipes and lodged among the gravel,
back through the perforations, and restore them to the bed.
As
When the whole bed is to be washed, as just described it will usually be most
desirable to close three of the valves 20. so as to admit the washing water into only
one of the compartments 2. 3. 4. 5 at a time. By this incans and by the partitions a
the pressure in the pipe D is concentrated on the small portion of the bed in and
directly over one of the compartments and thus the bed is agitated more violently
and the washing correspondingly oxpedited.
By means of the construction and operation which has been described the filter is
kept in good working order without the necessity of washing the whole bed except at
comparatively long intervals and thus a great saving of time is effected and also a
great amount of water is saved. Whereas in a filter in which the whole bed is
washed each time the top portion of the bed becomes foul, it requires from one to six
per cent of the water filtered to keep the bed properly washed, in the present filter
the bed is kept properly cleansed by the use of from 1/10th to 1/4th of one per cent
of the water filtered.
In some cases it may be found more desirable to wash the bed with unfiltered
instead of filtered water. The construction shown permits of this when desired. To
do this it is only necessary to close the valve 21 and open the valve 18 and operate
the other valves in the same manner as already described.
It has been found, as before stated, that in some cases the impurities contained in
the water are of so fine a nature that they will not all be arrested by the bed F but
that some portions of the impurities will be carried through the bed and remain in the
water unless the bed is made of great thickness. To avoid this it is sometimes
desirable as before stated, to introduce a precipitating substance with the water
which will act to precipitate or accumulate the impurities so that they will be more
readily arrested by the material of the bed. For this purpose the filter is provided
with a small chamber or receptacle m. which is located inside the filter and in position

page_text: to be in the current formed by the water as it flows into the filter. This chamber
contains the precipitating substance which it is desired to introduce into the water and
is so constructed that, as the water flows past it a small amount of the precipitating
substance will be carried out of the chamber and allowed to mingle with and be
distributed through the water. To accomplish this result the chamber m may be
constructed in a variety of ways. The construction shown in figures 1. 9. 10 and 11
however, is what is regarded as the best for the purpose. As shewn in these figures
the chamber m. is provided around its circumference with a large number of small
openings 1 and is provided upon its interior with a cylindrical shell n. which fits into
the chamber m. and is provided with corresponding perforations 1. The shell n. is
secured to an axis o. which passes through a stuffing box in the top of the chamber m
and is provided with a suitable handle p by which it can be turned to different posi-
tions so as to cause the openings 1-1 to coincide with each other to a greater or less
extent, as best shewn in fig. 11. In order to enable the attendant to determine when
the openings 1. 1 are opened to the proper extent the handle p. may be in the form of
a pointer, as shewn in the present case, and the top of the chamber m. may be provided
with a scale 1. which will be graduated to indicate the extent to which the openings 1-1
are opened. The top of the chamber m will preferably be provided with an opening,
closed by a screw plug or cap r. through which the precipitating substance can be
introduced to the chamber from time to time.
The chamber m. being filled with the precipitating substance, the water as it enters
the filter through the pipe B will flow against the side of the chamber and a portion of
it will pass through the openings 1-1 and come in contact with the precipitating
substance so as to absorb or take up a small amount of the same and carry it out of
the chamber into the water in the filter. The amount of the substance thus taken up
by the water will depend upon the extent to which the openings 1-1 are opened, and
this can readily be adjusted by means of the handle pas has been explained so as to
allow more or less of the precipitating substance to be taken up by the water as may
When none
be required at different times owing to different conditions of the water.
of the precipitating substance is required the openings may be entirely closed. The
precipitating substance thus carried out of the chamber m will, by the current formed
by the water flowing into the filter, he carried to all parts of the water above the bed
so as to accumulate and precipitate the impurities and cause them to be arrested by
the bed as the water percolates downward through it. The precipitating substance
will also be arrested at the top of the bed so as to be prevented from passing out with
the filtered water. By this means the process of filtration is rendered continuous
and the precipitating substance is introduced into the water without in any way
interrupting the continuous flow of the water or appreciably impeding or obstructing
its passage through the filter.
Although it is preferable that the chamber m should be located in the position shown
in fig. 1 it is not necessary that it should be located in this position. As before stated,
it may be located in any position where it will be in the current of the water flowing
into the filter. And in some cases there may be more than one of the chambers m.
employed located in different positions. When the water flows into the filter and
passes through the bed simply by gravity the chamber m. instead of being attached to
the top of the filter may be located in the side of the filter, as indicated in fig. 12 in
such position that the stream of water as it flows in from the pipe B will fall upon the
side of the chamber.
It is to be remarked that while the construction and organization hereinbefore
described embodies the invention in its most complete and desirable form, it may be
modified in many particulars without departing from the essential features of the
Invention.
The number and arrangement of the pipes i. k may be varied and when it is
desired to wash only with filtered or only with unfiltered water, these pipes may be
connected only with the discharge or induction pipe, as the case may be. Only two
series of these pipes are shewn in the present case because two series will usually be
all that will be required, but it is to be understood that three or more series arranged

page_text: at different levels in the bed may be provided if in any case it should be found
desirable to employ more than two, or in some cases it may not be desirable or
necessary to provide more than one series of these washing pipes. The number and
location of these washing pipes will depend largely upon the condition of the water
being filtered. In some cases it may not be found necessary to provide the pipes i. k
with the valves 7 and pipes 6 and in some cases it may be found most advantageous to
provide for clearing the pipes i. k by extending these pipes through the opposite side
of the filter and connecting them to a cross pipe which is connected by a branch with
the waste pipe C. as indicated by dotted lines in fig. 1. The form and arrangement
of the pipes c. d and e. may also be varied and the vertical partitions a. may be
arranged to divide the lower part of the filter into a greater or less number of com-
partments than shown without departing from the invention. Although the partitions a.
perform an important function, as before explained, they may be entirely omitted and
yet preserve certain parts of the invention. If the partitions a. are omitted the
branch pipes d. may of course, be arranged in any convenient manner.
The pipes e. & may be perforated around their entire circumference, as shown, or if
preferred they may be perforated for only a part of their circumference, say two-
thirds more or less. So also, the pipes c. d'instead of being arranged excentrically of
the pipes e. b. may be arranged concentric with said pipes.
It is also to be remarked that in some cases it may be found desirable to force
Air used in this manner will
compressed air into the pipes with the washing water.
aid in agitating the granular material of the bed and will thus aid the water in
removing the impurities from the bed. In some cases air alone may be forced through
the pipes into the bed. In such case a small amount of water will be allowed to run
in through the induction pipe and the air passing upward through the bed will agitate
the granular material of the bed and carry the impurities to the surface of the water
where they will flow out through the waste pipe.
In the construction shewn in fig. 15 the bottom portion of the filter is provided with
only one of the vertical partitions a. and as a consequence is divided into only two
instead of four compartments. In this figure the enclosing pipes care omitted and
it will also be observed that in this case the branches d. increase in size from the point
of their connection with the pipe D to their inner ends. The purpose of this construc-
tion is to secure an even distribution of water over the entire area of the bed when the
water is sent through the pipe D in the reverse direction for the purpose of washing
the bed. It will readily be seen that if the pipes d. were of the same size throughout
their whole length the pressure in the branches c, farthest from the pipe, D, would,
during the washing operation, be much less than in those nearest to the pipe D.
by increasing the size of the pipes d. toward their inner ends the water flows along the
pipes more readily than into the branches nearest the pipe D and thus a uniforin or
practically uniform discharge of water from all of the branches c. is secured. It is
to be remarked that the pipes d. need not in all cases be perforated as in many cases
the perforations in the branches c will be all that is necessary.
C
But
The means for regulating the amount of the precipitating substance which should be
discharged from or carried out of the chamber 'm. by the water may also be varied, as
will readily be seen, without departing from the essential features of the invention.
Two of the many modifications that may be made in this apparatus are illustrated in
Figures 13 and 14.
22
In the construction shown in Fig. 13 the shell a instead of being perforated is made
in sections which are connected together, and the shell is arranged to be raised and
In this case the amount of the
lowered to cover and uncover the openings 1.
precipitating substance which will pass out of the chamber m. will be determined by
the number of the openings 1. which are uncovered, instead of by the extent to which,
they are uncovered.
In the construction shown in figure 14 the sides of the chamber m. are not per-
forated, but the bottom s. of the chamber m. is perforated and is provided with a valve
or false bottom t. which can be lowered to a greater or less extent to permit more or

page_text: less of the water to come into contact with a precipitating substance through the
perforations in the bottom s.
In either of these cases the rod o. may be provided with a pointer p. which will lie
adjacent to a scale 7. and thus indicate the position of the valve t. or shell .
The Inventor is aware that it has been proposed to introduce precipitating substance
into the water previous to its entrance into a filter and that it has been proposed to
accomplish this by locating the precipitating substance in a chamber which communi-
cated with the induction pipe and providing the induction pipe with a valve or gate
by which a greater or less proportion of the water passing through the pipe would be
directed into contact with the precipitating substance. This arrangement is however,
objectionable for the reason that the valve located in the induction pipe partially closes
the pipe and thus offers an obstruction to the passage of the water. Aside from this
the obstruction offered by the valve varies with the different positions of the valve so
that a uniform flow of water into the filter is prevented. By locating the chamber
containing the precipitating substance inside the filter body the induction pipe is left
practically unobstructed so that a perfectly uniform delivery of the water to the filter
is provided. By the construction shown in the present case also means are provided
for regulating the amount of the precipitating substance introduced into the water
with perfect accuracy.
In conclusion it is to be remarked that parts of this invention may be used without
the whole. The apparatus for introducing the precipitating substance into the water
can be used without the other parts of the apparatus. So also the washing pipes k. i
can be employed when the bottom portion of the filter and the discharge pipe or pipes
are constructed and arranged differently from what is shown. So also the construction
and arrangement of the discharge pipes shown may be employed without the washing
pipe or the partitions a. or parts of the invention relating to the discharge pipes
may be employed without using the whole.
Having now particularly described and ascertained the nature of the said Invention
and in what manner the same is to be performed as communicated to me by my foreign
correspondent I declare that what I claim is :-
:-
1. The combination with the filter and filtering bed of the perforated washing
pipes k. arranged horizontally in and a short distance below the top of the filtering
bed and extending substantially across the whole filtering bed and supplying washing
water throughout the whole upper area of the same at one and the same time and
connected separately to the pipe through which the washing water is supplied
substantially as described.
2. The combination with the filter, of a plurality of series of perforated washing
pipes. arranged horizontally in the filtering bed at different heights and connections
for sending the washing water into either of said series of pipes, substantially as
described.
3. The combination with the filter and its induction and discharge pipes, of the
perforated washing pipes . arranged horizontally in and a short distance below the
top of the filtering bed and connected separately to the pipe through which the
washing water is supplied, and connections between said last pipe and the induction
and discharge pipes whereby the top of the bed may be washed with either filtered or
unfiltered water, substantially as described.
4. The combination with the filter and its induction and discharge pipes, of a
plurality of series of perforated washing pipes arranged horizontally in the filtering
bed at different heights, and connections between said washing pipes and Both the
induction and discharge pipes, whereby the bed may be washed with either filtered or
unfiltered water, substantially as described.
5. The combination with the horizontal perforated washing pipes having the vertical
branches 6 at their ends, of the valves 7 for opening communication between the
washing pipes and said branches substantially as described.
6. The combination with the horizontal perforated washing pipes, of the rods 8

page_text: extending the length of said pipes whereby the granular material in said pipes may
be loosened so as to be carried out by the washing water, substantially as described.
7. The combination with the filter and the filtering bed and the discharge pipe
located in the bottom of the bed, of a perforated pipe surrounding the discharge pipe
and providing a space between the two substantially as described.
8. The combination with the filter and the filtering bed, of a perforated discharge
pipe located in the bottom of the bed, a perforated pipe surrounding said perforated
discharge pipe, and a body of course material f. located in the space between the two
pipes substantially as described.
9. A filter discharge pipe provided with several branches having valves or cocks for
directing the full force of the current through different portions of the filter bed in
cleansing the same, substantially as described.
10. The combination with a filter having its bottom portion divided into a number
of compartments of the discharge pipe arranged to communicate with each compart-
ment separately, substantially as described.
11. The combination with the filter having its bottom portion divided into a number
of compartments by vertically arranged partitions, of a discharge pipe having
perforated branches which communicate with each compartment separately, perforated
pipes enclosing the perforated portion of each of said branches and bodies of coarse
material f. located in the space between said pipes, substantially as described.
12. The combination with a filter having induction and discharge pipes arranged to
maintain a continuous flow of water through the filter, of the chamber m. located
inside the filter and containing a precipitating substance and provided with openings
through which a portion of the water passing through the filter is allowed to come
into contact with said substance so as to carry a portion of it out of the chamber;
substantially as described.
13. The combination with a filter having induction and discharge pipes arranged to
maintain a continuous flow of water through the filter, of the chamber m. located
inside the filter and containing a precipitating substance and provided with openings
through which a portion of the water passing through the filter is allowed to come
into contact with said substance so as to carry a portion of it out of the chamber, and
means for regulating the amount of precipitating substance discharged from the
chamber substantially as described.
14. The combination with a filter having induction and discharge pipes arranged to
maintain a continuous flow of water through the filter, of the chamber m. located
inside the filter and containing a precipitating substance and provided with the
openings 1. and the adjustable shell n. for regulating the size of the openings 1.
substantially as described.
15. The combination with the filter and the filtering bed, of the pipes d. communi-
cating with discharge pipe D and having the perforated branches c. and being of larger
size at their inner ends than at their junction with the pipe D. substantially as
described.
NEWTON & SUN,
Agents for the Applicant.