A NEW PURIFYING APPARATUS FOR STEAM BOILERS
Year: 1880

page_text: LETTERS PATENT to Alfred Dervaux, Engineer, of Brussels, in the Kingdom of
Belgium, for an Invention of "A NEW PURIFYING APPARATUS FOR STEAM
BOILERS,"
PROVISIONAL SPECIFICATION left by the said Alfred Dervaux at the Office
of the Commissioners of Patents on the 28th April 1880.
ALFRED DERVAUX, Engineer, of Brussels, in the Kingdom of Belgium. "A NEW
PURIFYING APPARATUS FOR STEAM BOILERS."
'This Invention relates to an apparatus capable of extracting automatically all
the calcareous and argillous substances or other impurities contained in the water
of steam generators in a state of suspension.
The special features in the Invention are,―
1. The general construction of a purifying apparatus for steam boilers, in which
feed or other water forced into a chamber or vessel of any shape erected above the
boilers is brought in direct or indirect contact with a mixture of steam and water
taken at the level in the boilers so as to produce automatically through the
condensation of the steam of said mixture an energetic circulation of the boiler
water from the boilers to the suction chamber, and from the latter back to tho
boilers, thereby passing through a suitable intervening decanting vessel in which it
will deposit all the calcareous and other earthy matter contained in suspension.
2. A particular construction of a suction vessel in combination with certain
pipes leading from it.
3. A pipe or pipes closed at the lower end, and provided laterally with one or
more clongated orifices ranging between the lowest and highest water level, so as
to ascertain the continual sucking up of the boiler water in spite of the fluctuations
of the level.
4. A vessel serving as a decanter or filter, or both, and its combination with a
chamber and boiler or boilers by means of the pipes, as to form a circuit for
the boiler-water, which runs from the boilers into said vessel and back to the
boilers.
The apparatus, as shown in the annexed Drawing, consists of a vessel D situated
a little below the water level of the boilers, and of another vessel E placed a certain
height above the said level, and communicating with each boiler Ɑ by means of a

page_text: pipe V, the opening of which is comprised between the maximum and minimum
water level.
The feed pipe C through which feed water is forced into the boilers by means of
a pump, injector, or other feeding apparatus is connected with the vessel Eat a
point A, and with the vessel D at a point F, and as these two vessels communicate
with each other by a pipe B the feed water entering at A into tho vessel E is forced
to flow from it through the pipo B into the vessel D, and thence through the feed
pipe C into the steam generators.
Before leaving the vessel E and descending into the pipe B the feed water is
brought in contact with the steam, which on arriving from the boilers through the
pipe V into said vessel is condensed by the feed water, and as the open end of the
pipes V descends partly into the water of the boilers, this water in mixing with
the said steam is violently drawn up towards the vessel E.
From the continual condensation of the steam of this mixture by the feed water
it follows that the boiler water taken from the surface of the level is inccssently
impelled towards the vessel E where it unites with the feed water, and then
returns to the generator by passing through the vessel D, in which it will deposit
the calcareous substances which it contained in suspension. These impurities will
settle at the bottom of the vessel D and may be easily removed by the discharging
cock R.
The apparatus may be applied indifferently to one or more boilers. In the case of
a range of boilers a single suction vessel E and a single decanting vessel D will
suffice. It will also be sufficient to provide one main suction pipe V, which has the
requisite number of branch tubes leading one into cach boiler; however, each
boiler must be furnished with a cock X so as to permit of purifying the water of
each boiler independently.
. Instead of condensing the steam, which is mixed with the boiler water and
enters into the vessel E by passing the feed water into the interior of this vessel,
this may be obtained by allowing it to circulate on its external surface. In this
case the vessel E becoming converted into a kind of surface condenser, the useful
effect of which increases with its cooling surface, it will be convenient to give it
the shape of a multitubular truss (fasciculus), or of a serpentine or any other
analogous form.
The same end will be attained by constructing the vessel E with a great cooling
surface so that the cooling will result from contact with the outer atmosphere;
this means however appears to me so little economical that I could scarcely
recommend it save in those cases where the lost heat might be utilized otherwise,
for instance, by heating a dryer.
It will be easily understood that the suction chamber E as well as the decanting
vessel D may be constructed in a variety of shapes, and that they may be com-
bined so as to form a single vessel. The vessel D may also be placed at a level
above that of the boiler and combined with a filter if desired
The descending pipes V instead of being closed at their lower end and provided
with one or several lateral orifices may be open at their lower ends; they may
be entirely suppressed provided that a pipe V proceeds laterally from cach boiler
so that its opening will be comprised between the lowest and highest water level.
Besides, the descending pipes V may be provided with gauge taps N permitting to
ascertain the condition of the water in the boilers and the height of its level.
An essential point in the construction of the apparatus is to choose for the pipes V
an adequate section, and to erect the chamber E at a point sufficiently high so that
'the feed water forced into this chamber shall condense as much steam and conse-
quently suck up from the generator as much water as will be possible.
For the same purpose the suction pipe V is brought in direct communication
with the pipe B by means of a pipe connection H. Thus a portion of the boiler
water while drawn up with the steam will be directly discharged from pipe V
into B without passing through the vessel E, where it would but unduly raise the
temperature of the feed water by combining with it.

page_text: It will be very useful if not indispensable to provide in the upper part of the
pipe V a retaining valve S, which opens in the direction of the arrow and closes
in a contrary direction, so as to allow the steam and water mixture to circulate
only from the boilers towards the pipe H and chamber E.
For the purpose of rendering the circulation of the boiler water towards the
chamber E continuous in spite of the fluctuations of the level, the end of the pipes V
which descend into the boilers is closed, and said pipes are provided laterally with
a number of small and elongated orifices extending throughout the whole height
comprised between the lowest and highest water level, and having a total section
equal to that of the pipes themselves.
In certain boiler systems it happens that the impurities precipitated by ebullition
in the extensively heated portions of the generator do not remain suspended in the
water, but will settle in the less heated lower portions from whence it would be
impossible to extract them by circulation. In such cases and according to the
boiler type we so arrange a number of partitions consisting of metal plates as to
prevent any descending current which night tend to start up in the interior of
the boilers. By this means the precipitated matter is retained in the intensely
heated portions and maintained there in suspension by the ebullition of the water.
In boilers, for instance, having lower warming tubes, I close the communications
between the main boiler and the warming tubes by means of a partition which is
provided with a large opening in the middle, covered by a retaining flap or other
valve opening upwards and closing downwards so as to prevent any descending
current as stated before.
In some cases where the feed water is liable to produce incrustations it is
proposed to use a "disincrustant" such as carbonate of soda or any other effective
substance, according to the nature of the water by which the incrustations will be
transformed into mud which can be easily extracted from the boiler by my
apparatus in the measure of its formation, thereby maintaining the boiler water
always clear. The application of desincrusting substances, the use of which may
always be regulated very easily is thus rendered both practical and economical.
The apparatus is applicable to those automatique boiler feeders which are
situated above the boilers and connected with them by a steam pipe going down
to the normal water level. I complete these feeders which are already partly
adapted for the application of this system by adding a decanting or filtering vessel
as well as the necessary pipe connections and other devices so as to assure the
extraction of the calcareous matter.
"
The accompanying sketch represents an arrangement on a boiler having a
heating surface of 100 square meters drawn to the scale of about 1-20. This
arrangement as well as the details of construction of the different parts of the
apparatus may be modified at will, provided that the principle and means of action
of the apparatus are observed.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alfred Dervaux in the Great Seal Patent Office on the 25th October
1880.
ALFRED DERVAUX, Engineer, of Brussels, in the Kingdom of Belgium.
PURIFYING APPARATUS FOR STEAM BOILERS."
" A NEW
The object of my Invention is to construct an apparatus by which the water in
steam boilers may be purified while the boiler is in operation, and this object I
obtain by combining with the boiler and feed water apparatus a receptacle through
which the boiler water is caused to circulato automatically and deposit therein the
calcareous and other matters which it contains in suspension, as more fully described
hereinafter.
The accompanying Drawing illustrates a sectional view of my improved apparatus
applied to the rear end of an ordinary steam boiler, and C, C, C, the feed pipe
provided with a cock e, and through which water is forced into the boiler by means
of a pump, injector, or other feeding apparatus.
The portions C and C' of the feed pipe communicate with each other through a
vessel E above the water level of the boiler, and through a pipe B and a vessel D
below the water level. Connection is made between the portion C" of the feed
pipe and the vessel E at A, and between the portion C and the extreme upper end
of the vessel D at F, while the pipe B extends downward some distance into
the vessel D, and is preferably closed at its outer end, and provided with an
elongated lateral slot near its end.
With the upper end of the vessel E communicates a pipe V, the other end of
which passes into the boiler and is closed at its extreme end, but is provided with
a lateral opening or openings extending between the highest and lowest points of
the water level, the mean level being shown in the Drawing.
The pipe V is provided with a cock f, and preferably also with a check valve S
opening in the direction of its arrow, while I also prefer to make a direct communi-
cation between the pipes B and V through the pipe H.
The feed water entering at A into the condensing vessel E is forced to flow
through the pipe B into the depositing vessel D, and thence through the feed
pipe C', C, into the steam boiler. Before leaving the condensing vessel E however
the feed water is brought into contact with the steam which rises through the
pipe V from the boiler into the said vessel E, and the consequent condensation of
this steam produces a vacuum in the pipe V, so that the water in the boiler is
violently drawn towards the vessel E. From the continued condensation of the
steam of this mixture by the feed water the boiler water is drawn up into the
vessel E and pipe H where it unites with the feed water, and thenco returns to the
boiler through the vessel D, in which it will deposit the calcarcous matters it
contained in suspension. These impurities will settle at the bottom of the vessel D
and may be easily removed through the valved discharge pipe R.
The suction or condensing chamber E and the decanting or depositing vessel D
may be constructed in a variety of shapes, and may be combined so as to form a
single vessel.
The vessel D may be placed at a level above that of the boiler and be combined
with a filter if desired.
An important point in the construction of the apparatus is to make the
pipes V of the proper size and to arrange the suction and condensing vessel E nt a
point sufficiently high so that the feed water forced into this chamber shall
condense as much steam and consequently exhaust as much water from the boiler
as possible. For the same purpose the suction pipo V is brought into direct
communication with the pipe B by means of the connection H. Thus a portion of

page_text: the boiler water while drawn up with the steam will be directly discharged into
the pipe B without passing through the condensor E.
Instead of condensing the steain by bringing it into immediate contact with the
feed water the vessel E may be so constructed as to allow the steam to circulate on
the external surface of the water-chamber. The vessel E being in this case
converted into a surface condenser it will be advisable, in order to increase its
cooling surface, to made it multitubular, or in the form of a coil, or the vessel E may
be made with a large cooling surface so that the cooling will result from the outer
contact of the atmosphere.
In the latter case the vessel E should be made of iron or copper sheets, whereas,
in the case of using foed water, it may consist of a sinall cast iron vessel which is
less expensive.
The pipe V may have its lateral orifices closed and its lower end open and
descend entirely into the boiler water, then two cases are to be considered.
In the first case, concerning multitubular boilers or boilers with circulation in
which the mass of water is in a state of mixture with the steam, the column of
water in pipe V will also consist of a mixture of water and steam of the same
reduced density as that in the boiler, whereas the descending column B, cooled either
by contact with the atmosphere or by mixing with the feed water will necessarily
be denser, consequently there will be a suction and a circulation of the boiler water
towards the decanting vessel. This suction will be the more energetic. the higher
the vertical column V rises above the boiler and the better the descending column B
is cooled by the external air or by being mixed with the feed water, or by being
cooled by the feed water circulating outside the pipe B. It is for this reason that
the application of the intermediate condensing vessel E, although not indispensable,
is nevertheless of great utility. Indeed it will be easily understood that the
vessel E, which is only an accessory, might be entirely suppressed in most of the
cases. The feed water might be directly discharged into the column B by the
dotted tube, and if this is not required circulation may be obtained by cooling
directly the descending column B.
In the second case, referring to ordinary boilers, in which the mass of boiler water
is not in the condition of a mixture with the steam, in this case also the pipe V
may go down into the boiler water, even down to the bottom of the boiler. It
suffices to provide the pipe V, at x for instance, with a small pipe and cock com-
municating with steam space of the boiler, and being regulated at pleasure, or with
a number of small openings at y in order to produce the required effect. In this
Icanner the mixture of water and steain necessary for the circulation is easily
obtained, and may be so from any point in the mass of the boiler water by simply
placing the end of the pipe V accordingly. The pipo may also extend laterally
from the boiler.
However, it will be preferable to extract the water at the level, as shown, because
the matters in suspension will be generally thrown up to the level of the water by
the ebullition of the same.
The pipe V may be provided with a test cock at any convenient part in order to
ascertain the condition of the water in the boiler.
My apparatus may be applied to one or more boilers. In the case of a range of
boilers a single condensing vessel D will suffice, and it will be sufficient to provide
one main suction pipe V, which has the requisite number of branch tubes, each
however being provided with a valve f, so that each tube may be purified
separately. The apparatus may also be applied to automatic boiler feeders, which
are arranged above the boiler and connected with them through a steam pipe
extending to the normal water level. These feeders being already partly adapted
for the improvement, I complete the apparatus by combining therewith a decanting
or filtering vessel, together with the necessary pipe connections and other devices,
so as to assure the extraction of the calcareous matters from the boiler water.
In some boiler systems it happens that the impurities precipitated by ebullition
in the intensely heated portions of the generator do not remain suspended in the

page_text: water, but will settle in the less heated lower portions, from whence it would be
impossible to extract them by circulation. In such cases, according to the con-
struction of the boiler, a number of partitions may be arranged so as to prevent
any descending current which might tend to start up in the interior of the boiler.
By this means the precipitated matter is retained in the intensely heated portions,
and maintained therein in suspension by the ebullition of the water.
Where the feed water is liable to produce incrustations a disincrustant, such as
carbonate of soda, may be used, by which the incrustations will be transformed into
mud, so that it can be easily extracted from the liquid by my apparatus.
Having now described the nature of my said Invention, and in what manner the
is to be performed, I declare that I claim,-
1. The combination of a steam boiler and its feed pipe, communicating with the
boiler through a condensing vessel and a depositing or filtering vessel, with a pipo
communicating at one end with the upper part of the condensing chamber, and
extending at the other end to the water level in the boiler, all arranged substantially
as and for the purpose described.
2. The combination of a steam boilor and its feed pipe with a depositing or
filtering vessel and a condensing vessel, and a pipo B through which the feed water
passes, with a pipe communicating at one end with the upper part of the condensor
and at the other end with the water level in the boiler, all substantially as set
forth.
3. The combination of a steam boiler, its feed pipe, and a depositing or filtering
vessel, a condensing vessel, and pipe B through which the feed water passes, with
a pipe V communicating with the upper end of the condenser and branch H,
substantially as specified.
4. The combination of a steam boiler, its feed pipe, and a depositing or filtering
vessel, and condensing vessel through which the feed water passes, with a pipe V
communicating with the upper part of the condenser, and passing at its other end
down into the boiler, and provided with lateral openings extending from the highest
and lowest points of the water level, substantially as specified.
5. The combination of a steam boiler, its feed pipe, condensing vessel, and
decanting vessel, with a pipe V communicating with the upper part of the condenser,
and passing with its other open end at any point into the boiler, and extending to
any point in the mass of the boiler water, said pipe V being provided either outside
the boiler with a small pipe communicating with the steam space, or inside the
steam space with openings for the entering of steam, substantially as described.
6. The combination of a steam boiler with a purifying or decanting vessel by
means of a pipe V rising from the level or from any other point in the mass of the
boiler water, pipe B, and pipe C¹, C, but without the condensing vessel E and feed
pipe C, the circulation of the water from the boiler to the decanting vessel being
obtained by cooling the column B by any of the means specified, all substantially
as set forth.
In witness whereof, I, the said Alfred Dervaux, have hereunto set my hand
and seal, this Eighteenth day of October, in the year of our Lord One