Improvements in or Appertaining to Filtering or Purifying Feed Water for Steam Boilers and the like, and in Apparatus therefor.
Year: 1890

page_text: Date of Application, 9th Dec., 1890
Complete Specification Left, 8th Sept., 1891-Accepted, 10th Oct., 1891
PROVISIONAL SPECIFICATION.
Improvements in or Appertaining to Filtering or Purifying Feed
Water for Steam Boilers and the like, and in Apparatus
therefor.
J, JAMES BROWN EDMISTON, of Highfield Road, Walton, in the County of
Lancaster, Engineer, do hereby declare the nature of this invention to be as
follows:-
--
This invention has for its object a filter applicable for filtering the feed water of
marine, land and other boilers, and for other like purposes. It also applicable
for extracting the oil and grease, copper, free acid, and other impurities from the
water. By my invention, I filter out mechanical impurities, and, if desired, in great
part neutralise or extract the free acids before the water is allowed to enter the
boiler.
For the carrying out of my process, I have designed the following arrange-
ments:-
I form a box or cylinder or other vessel with a series of metal perforated plates,
or metal strips with flannel or other filtering material in the apertures between the
metal strips, separated by skeleton frameworks of wood or other suitable material
used for keeping them sufficiently apart. These perforated plates or frames are
covered on each or one side with the filtering material, preferably woollen flannel,
and, between the filtering material, charcoal or other purifying substances may be
used. The cylinder, box or vessel being fitted with these plates, the water is
pumped through it from the one side to the other in its passage to the boiler or
boilers. Each of the plates and frames is perforated or provided with orifices near
the bottom, and, in these perforations or orifices, valves or doors, or it may be a
plug is fixed, so as to prevent the water from passing directly through the
perforations or orifices from the one side to the other. The plates are held in
position by set screws, keys or slides. A pressure gauge indicates to the attendant
whenever the filter becomes so clogged as to form any great impediment to the
passage of the water. On the side nearest the pump, I may place an automatic
alarm or safety valve, so that, should the filter be so clogged as to be unable to
freely pass all the water supplied, the alarm can be at once given and another filter
put in circuit instead, or the feed water passed for the time being through feed
pipes in the usual way. I may also place an air vessel with an air escape on the
filter, preferably on the inlet side, where high speed pumps or single acting pumps
are used and high pressure applied to the pumps, to reduce the pulsation or cause a
steady pressure in the filter, or it may be on the delivery side. By this means, at
each pulsation of the pump, the filter cloths are pressed one way, and by the
expansion in the air vessel between each pulsation, they are pressed the other way,
thus a constant vibration is kept up, tending to keep the filtering material clean.
In the filter at the receiving or delivery end, (but preferably at the delivery end)
I prefer to place a series of zinc plates hanging in the filter, or between the frames
or plates, and in the line of flow, so that the water must flow amongst them. These
have a tendency to attract and form neutral salts with the organic and other
acids in the water. These plates are easily renewed or replenished from time
to time.
One, two or more of these filters can be placed on either the suction or delivery
side of the pumps & they may be parallel or in other positions, so that any one can
be put into action while the other or others is or are cut off. Or all can be cut off
and boilers supplied with water in the usual way. The filters can be cleaned,
either by lifting the plates out, or in the following manner, namely, by forcing

page_text: steam, by means of a pipe or cock, or hot water, through the filter, or by closing
all exits, filling the filter with steam at high pressure, thus boiling the contents of
the filter. The deposit loosened from the flannel or other suitable material by any
of these means falls down to the bottom, when, the plug being withdrawn or the
valves opening with the force of the steam, the dirt can he withdrawn into a trap
from the passage formed by the perforations or orifices in the plates and frames.
The trap can be cleaned or blown out by opening a valve in connection with it.
It will be obvious that, instead of perforated plates, reticulated or other porous.
partitions can be used, also that a layer of asbestos, slag, charcoal, wool or other
material can be used to take off the larger part of the impurities before entering the
filter or filters.
Dated the 8th day of December 1890.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Patent Agents for the Applicant.
therefor.
I, JAMES BROWN EDMISTON of Highfield Road, Walton, in the County of
Lancaster, 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 :-
This invention has for its object a filter applicable for filtering the feed water of
marine, land and other boilers, and for other like purposes. It is also applicable
for extracting the oil and grease, copper, free acid and other impurities from the
water. By my invention, I filter out mechanical impurities, and, if desired,
in great part neutralise or extract the free acids before the water is allowed to
enter the boiler.
Referring to the drawings:-
Figure 1 is a plan,
Figure 2 an elevation, partly in section, of my apparatus,
Figures 3 and 4 enlarged views of plates.
Figures 5 and 6 are elevations showing two modified ways of working the
filter.
Figure 7 shows the filter combined with a feed water heater.
In these
A, is the feed pipe leading from the feed pump or source of supply branching off
into two or more branches A', each supplied with stop cock B or valve. C is a
strong box or chamber of any convenient shape, preferably cylindrical or as nearly
cylindrical as practicable, Ď air vessel; E, safety valve which may be placed
either on apparatus or feed pipes A; F blow off cock or valve; G pressure gauge;
H lid or cover of box C; a series of plates shown in detail in Figures 3 and 4,
and more fully described hereinafter; J, spacing frames of metal or other material
placed between plates II, and formed as an open network or skeleton so as to
allow the free passage of liquor through them opposite and near all perforations
in plates II; K, set screws holding the plates and frames in place; L, cage or
series of open zinc plates or bars hanging from screws K, and allowing free passage
of the water among them; M¹ exit pipes; N, stop cocks or valves similar to B B;
M, final exit pipe to boiler into which pipes M and M' converge; O, pipe through
which the water can pass instead of through the filters, in case, at any time, both
valves B had to be shut down; P cock or valve governing this pipe in the same
manner that cocks or valves B or N govern their respective filtering apparatus ;
QQ' nozzles with stop cocks by which steam can be admitted to either of the

page_text: filters. Soda cups may, if desirable, also be applied to these nozzles, so that, if
wanted, soda may be injected for cleaning purposes.
J, Figures 3 and 4, are the spacing frames and I the plates. These latter are
preferably of hard wood, such as teak, and are perforated with numerous holes R,
except where opposite the skeleton frames J. S S, Figure 2, are stout cloths,
preferably flannel in two thicknesses, which are nailed, screwed or otherwise
clamped to their respective plates I. T is a passage formed entirely through both
the plates I and frames J. This can be right on the floor of the box or a little
above it, as shown, and is preferably arranged with a valve or a plug W to prevent
the water passing in the direction of the arrow, but opening with pressure in the
contrary direction. This valve or valves can, however, be controlled by a screw V
from the outside, as shown in Figure 2, instead of working automatically. Orifices U,
shown in dots, Figure 3, pass down through the frames to the passage T to deliver
the dirt therein.
The mode of action of this apparatus is as follows:-
One of the valves B being opened and the valve P being closed, the feed water
from A passes to whichever of the chests C is opened to it through the valve B
being open.
The valve W being automatically closed against the force of the water, the
water has to pass through the various flannel sheets S S until it arrives opposite
the cage L.
In the course of its passage, it has been filtered from all but the very
finest solid material. At L, it comes into contact with the zinc plates which are
in electrical contact with the iron or brass screws K. The result is that a galvanic
action is set up and any acids present in the water, that come in contact with the
zinc plates, combine with or decompose the latter, forming a neutral zinc salt not
injurious to the boiler. The water then passes on from a valve N and pipe M' to
the delivery pipe M. After a time, the cloth filter will get somewhat clogged with
dirt, and this clogging will increase until the water will have a difficulty in passing
through. The pressure gauge G will then rise and give the indication, and, if this
indication be not observed, the safety valve E will open, allowing water to escape.
Any ordinary alarm attachment can be connected with the safety valve, so that,
should this open, an alarm will be given. The engineer, finding that the filter is
clogged, immediately opens the other valve B and closes the one connected with
the spent filter. The filtering water now passes through the other filter.
In order to clean a spent filter, the engineer shuts down the valve N connected
with it, and, by means of the cock Q, passes steam into the filter in the opposite
direction to that in which the water flows. While the filter had been in action, the
pulsations of the pump, combined, to some extent, with the action of the air
vessel D (especially when the latter is on the delivery side of the filter) had kept
the flannel of the filter in a constant state of tremor, thus causing the dirt settling
on the flannel to fall down to a considerable extent and enter the passage T, which,
however, has, up to this time, been closed by the valve W. When, however, the
steam is let in through the cock Q, the valve W opens or is opened, and all this
dirt is forced out at once, and escapes through the cock F which is also opened.
If now the valve W be closed by the screw V, the steam is forced to pass through
the flannels, thus driving out most of the dirt which was lodged in them. Again,
the valve W being open, this dirt is driven out as before. If now the cock be
closed, the whole chamber C fills with steam, and the little remaining contents of
the filter are well boiled. On again opening the valve W and the cock F, nearly
all the remaining dirt in the chamber is removed. The steam is then cut off and
the cock F is closed, the apparatus being now ready for use when the companion
filter is fouled.
If, by any chance, both filters, or as many filters as there are, are all fouled or
out of order at the same time, valve P is opened and the feed water enters the
boiler, without filtering, through the pipe O, just as if there had been no filters at
all. When the filters are found to be extremely dirty or defective and cannot
sufficiently be cleaned by the aid of steam, the covers Ĥ are removed, the various

page_text: plates I and trames are taken out, and the filter cloths attended to in any desirable
manner.
If desirable, the spaces within the flanges J may be filled with charcoal or other
purifying substances.
It will be obvious that, instead of, or in addition to, the perforated plates,
reticulated or other porous partitions (such, for example, as wire gauze) can be
used, also that a layer of asbestos, slag, charcoal, wool or other material can be
used to take off the larger part of the impurities before entering the filter or
filters.
The filter may sometimes be placed on the suction side of the feed pump or
pumps, as in Figure 5, and worked solely by the suction of said pump or pumps.
In this case, the air vessel D and safety valve E are unnecessary, and the
pressure gauge G is replaced by a vacuum gauge G located at any convenient
point between the pump and the filtering diaphragms, but preferably on the delivery
end of chamber C.
When working with a suction, however, or with only slight pressure, I prefer to
form the filtering layer of sponge, wool or other very porous material.
In some cases,
may place the filter between the hot well or bottom of condenser
and the feed pump or pumps, and connect the filter with the exhaust steam pipe
leading to the condenser in such manner that the impurities in the exhaust steam
are arrested before they reach the condenser and are passed into the filter, being
thereby arrested before getting to the pumps and prevented from entering the
boilers with the feed water. The details of this arrangement will be understood
by reference to Figure 5. X is the condenser. A is the feed pipe to the filter,
which, in this instance, is shown connected with the bottom of the condenser, the
latter thus forming the hot well. Or the pipe A may be connected with the usual
form of hot well c', as shown in dotted lines in Figure 5. X is a pipe conducting
the exhaust steam to the top of the condenser.
M is a pipe leading from the filter to the feed pump and through it to the boiler.
The pipe X', from the engine or engines to the condenser, may communicate with
a trap X having a diaphragm X3 placed transversely to the course of the exhaust
steam, so that the said steam impinges upon it, and the dirt and oil held in
suspension and any steam that may condense in the pipe are thereby caused to fall
down into the trap below the diaphragm. The trap X2 is connected by a pipe X
with the filter on the side nearest the condenser, so that all the oil and dirt carried
along by the exhaust steam from the engine is deposited in the filter, and the
purified water from the trap is passed again into the boiler along with the water
from the bottom of condenser or hot well.
It may sometimes be found desirable to provide means whereby soda or other
alkali or chemical may be introduced into the feed water, preferably into the filter
on the delivery side thereof, for the purpose of forming neutral salts with some of
the impurities in the water. Y, Figure 5, is a cup somewhat similar to an ordinary
tallow cup, into which such soda or other chemical may be introduced through a
cap Y. The Y
cup may be connected with the upper end of the steam cock Q
aforesaid, as shown in Figure 5, so that the chemicals can be discharged into the
filter and so be passed into the boiler with the water.
The cup may be provided near its upper end with a connection to a steam pipe Q
which latter is also provided with a cock Q³.
In cleaning the filter, the steam is blown through both the cup Y and the cock Q
in a similar manner to that already described. The cup may also be used for
introducing detergents into the filter when blowing through as above described.
The filter may also, in some cases, be worked by a vacuum or by a very small
pressure without the aid of a pump, as shown in Figure 6. In this case, the filter
is placed in the reverse position from that in which it appears in Figure 5. The
delivery pipe M is connected with the condenser, its end opening within the con-
denser at a point above the level of the water in the bottom thereof, so as to
communicate with the vacuum space in the condenser, and the pipe X' from the

page_text: trap is led to the suction side of the filter, as shown. The water from the trap X
is drawn through the filter by the difference of the vacuum in the pipes X¹ and M
and the small head of water in the trap X' and connecting pipe X.
It will be obvious that, instead of connecting the pipe X with the trap for the
purpose of purifying the water of condensation from the pipe X', it may be con-
nected with a tank X' or other supply of water, as shown in dotted lines in
Figure 6, the filter being worked as before by the difference of vacuum in the
pipes M and X and the head of water in the tank and supply pipe therefrom.
Figure 7 shows how the filter may be used in combination with a feed water
heater. The latter, which is preferably placed on the delivery side of the filter,
may consist of a chest Z provided with an inlet Z', outlet Z and blow off cock Z³,
and of a sinuous or convoluted steam pipe Z passing through the chest. Portions
of the pipe within the chest may be enlarged, as shown. Steam from the boiler
enters at Z, and passes out at Z to the bottom of the boiler. The water passing
from the filter through the chest Z has its temperature raised to such a degree that
a portion of the lime salts etcetera, in the water, is deposited within the chest
before the water enters the boiler. The salts may be blown off at intervals at the
cock Z³.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what 1
claim is :-
1. An apparatus for filtering or purifying feed water, in which the water is
passed successively through a series of flexible filtering fabrics supported at their
edges upon a series of more or less vertical porous partitions and separated by
spaces, within which the impurities, arrested by, and subsequently falling off from,
the filtering fabrics, may be collected, and from which they may be discharged from
time to time through suitable openings at or near their lower ends, substantially as
described.
2. In an apparatus of the kind described, the combination of the porous
plates I, filter cloths S, and spacing frames J placed one against the other across
the water way as described, and all pierced at or near their lower ends with a valve
controlled passage T communicating with the said frames J, substantially as and
for the purposes described.
3. In an apparatus for filtering or purifying feed water, a series of zinc bars or
plates or a zinc cage suspended or otherwise supported in the waterway and in
metallic contact with iron or brass studs or other supporting devices of like
material, substantially as and for the purpose described.
4. The improved apparatus for filtering and purifying feed water, taken as a
whole, substantially as shown and described.
1001
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Nottingham, and London, Patent Agents.