Improvements in and connected with Means for Heating and Purifying Feed-water for Boilers.
Year: 1895

page_text: Date of Application, 17th Dec., 1895
Complete Specification Left, 15th Sept., 1896-Accepted, 5th Dec., 1896
PROVISIONAL SPECIFICATION.
Improvements in and connected with Means for Heating and
Purifying Feed-water for Boilers.
I, WILHELM SCHMIDT, of Ballenstedt on the Harz, in the Duchy of Anhalt,
German Empire, Civil Engineer do hereby declare the nature of this invention
to be as follows:-
This invention refers to a method of highly exhausting the calorific power of
boiler furnace gases on generating steam and purifying feed-water. Said method
is in general characterized by causing steam that is generated within any suitable
type of boiler to give its heat or a part thereof off to feed water (intended either
for the boiler that produced said steam or for another one), so that the said steam is
thereby condensed, or turned into water of condensation respectively; and by
turning said water of condensation or a part thereof again into steam by exposing
it also to boiler furnace gases, preferably to the waste of those afore mentioned.
The steam to be condensed need not be the whole steam produced by the boiler just
employed; and the said water of condensation when exposed to said waste gases
need not form a column or other body of stationary or flowing water, but may, if
desired, be transformed into a state of suspension by aid of steam, as is all more
fully described hereinafter.
There result from the statements afore given a number of different manners of
working, the more important of which are the following:
1. All the steam generated is condensed, and all the water of condensation is
re-turned into steam.
2. A portion only of the steam is condensed, and all the water of condensation is
re-turned into steam;
3. A portion only of the steam is condensed, and all the water of condensation is
re-turned into steam after being suspended within the other portion of the first-
mentioned steam.
4. All the steam generated is condensed, and a. part only of the water of
condensation is re-turned into steam ;
5. A portion only of the steam is condensed, and a part only of the water of
condensation is re-turned into steam; and
6. A portion only of the steam is condensed, and a part only of the water of
condensation is re-turned into steam after being suspended within the other portion
of the first-mentioned steam.
By employing my novel method, especially with any of the manners of working
nfore enumerated, there is offered a possibility of producing great quantities of dry
or even superheated steam within a boiler of very small dimensions, and with the
consumption of very small quantities of fuel, and the main-boiler as well as the
auxiliary one (within which the water of condensation is re-turned into steam)
remain, moreover, practically free of incrustations.
My invention may be carried into practice by a variety of constructions of
boilers, feed water heaters, superheaters, and the like, and in order to make my
invention more clear, I have shown as examples two forms of construction in the
accompanying drawing, in which similar letters denote similar parts throughout the
different views and in which ;-
Figure 1 is a vertical section through a vertical boiler combined with a tubulous

page_text: boiler and a feed-water heater; and Figure 2 is a similar view representing a
modified arrangement.
The steam-space of the boiler a (Fig. 1) is connected by the pipe c with the
upper end of a coil g arranged within the vessel. The latter together with said
coil form the heating device for the feed-water. The lower end of the said coil is
connected by the pipe e with a tubulous boiler b, which in the form of construction
shown is composed of a column of flat coils forming a continuous way for the water,
or water and steam, passing through them. Said pipe e is connected with the upper
end of said coils, and the water, or water and steam, passing through them, is or
are thus compelled to flow in a direction opposite to that of the fire-gases, or more
precisely to the waste-gases, escaping from the furnace k. I wish it, however, to be
understood, that the connection of the said coils among each other, and with the
pipe e, may well be made in such a manner, that the water, or water and steam,
flows or flow in the same direction as do said waste-gases, or partly in the same
direction, and partly in the reverse one.
The feed water to be heated is led into the vesself through the pipe m, and is
led off in a heated state through the pipe n.
Said feed water and the steam that
passes through the coil g flow thus in this case, too, in opposite directions, but I
wish it again to be understood, that I not limit myself thereto.
In either case,
however, I prefer to arrange the feed water heater fg in such a height with regard
to the tubulous boiler b, that the water of condensation formed within the coil g
may freely flow over into said boiler 6 without any auxiliary means.
The water contained within the vesself is, as a matter of course, heated by the
steam passing through the coil g. Owing to the great quantities of steam that may
be led through said coil said water may, in fact, be heated nearly up to the
temperature of the water within the boiler, and those impurities which later on
might be separated within the boiler by the heat of the latter, and might therefore
contribute to the incrustation of the same are thus caused to separate before.
and may then easily be caused to precipitate, especially if the vesself is a suitable
wide one.
The steam generated within the boiler a need not, as a matter of course, all be
caused to pass through the coil g, but a certain part thereof may be led on a direct
way off to the place of use; said part may, however, prior thereto be dried or
superheated, for instance by letting it flow through one or more of the coils of the
tubulous boiler b.
The water of condensation flowing from the pipe e into the coils b is re-heated
within the same, and again turned into steam, and the latter is then either dried
only, or superheated, too.
To exhaust the calorific power of the waste-gases in the highest possible degree,.
and also to regulate the degree of superheating of the steam formed within the
coils b, I prefer to make use of the modified arrangement shown in Figure 2. The
coils b are in this case, put in direct connection with the steam-space of the boiler a
by means of the pipe d; the pipe c (leading the steam, or more precisely a part
thereof, to the feed-water heating coil 9) proceeds from said pipe d, and the pipe e
(leading the water of condensation off the coil g) terminates into the said pipe d
above the commencement of the pipe c. A pipe of somewhat smaller diameter
connects the boiler a with the pipe e, and a cock h arranged at the place of junction
of the pipes i and e allows of letting the water of condensation pass either wholly
to the pipe d, or partly to the latter and partly to the pipe i.
Supposed, the position of the cock h be such a one, that the pipe i is closed, all
the water of condensation formed within the coil g will flow into the pipe d above
the commencement of the pipe c. The steam streaming from the boiler a into said
pipe d divides at said commencement of the pipe c, one part passing through the
latter into the coil g, and the other part passing directly to the tubulous boiler b.
Said latter part of steam meets, and receives, the water of condensation emanating
from the pipe e, and carries said water with it in a suspended state into said
boiler b. The suspended water is evaporated within the upper coils of the

page_text: tubulous boiler b, and the whole quantity of steam thus obtained is first dried
within the middle coils, and then superheated within the lower coils of said boiler.
Owing to the wetness of the steam that passes into the tubulous boiler b, or more
precisely into the upper coils of the latter, the waste-gases the heat of which has
already been used up to a great measure by the lower and middle coils will now
give off the last part of their useful heat to said upper coils. To attain that high
exhaust, the upper coils need not indispensably offer (just by reason of said wetness
of the steam) a very large area of surface, and said high exhaust may thus be
obtained in a comparatively small space.
In order to make the several stages in the transition of the heat (from the fresh
steam to the feed-water, and from the waste-gases to the wet steam) more clear,
I will assume, that the steam generated within the boiler a possesses a pressure
of 11 atmospheres, and passes through the pipes d and c with a temperature of
about 180°, and that the feed-water enters the vessel with a temperature
of about 30°. Said water on slowly rising from the pipe m to the pipe n is heated
up to about 160°, whereas the steam will be turned into water of condensation
having a temperature of about 60°. The fall of temperature amounts, therefore, at
the upper end of the coil g to about 20°, and at the lower end of the same to
about 30°, and it is thus to be seen that every part of said coil heats the feed-water
with nearly the same power.
An equally advantageous fall of temperature is to be found in the furnace gases
with regard to the water and steam flowing in an opposite direction through the
coils b. The steam (having a certain amount of water of condensation suspended
within it) possesses a medium temperature of about 180°, and is first acted on by
fire-gases having a temperature of about 250°, the difference amounting thus to
about 70°. The mixture of water and steam on flowing down within said coils is
completely turned into steam by the fire-gases; that steam is then dried and
finally superheated, the degree of superheating amounting up to about 300°. The
temperature of the fire-gases acting upon the lowermost coils is about 600°, whereas
the temperature of the gases acting upon the uppermost coils amounts to about 250°.
The fall of temperature of said gases is thus a highly remarkable one, and is in this
magnitude obtained only by letting the steam entering the tubulous boiler b be
very wet.
In case, the quantity of water of condensation be so great that either said water
cannot completely be evaporated within eaid boiler b, or the steam produced out of
the said water cannot be sufficiently superheated, let a part of that water ran
back through the pipe i into the boiler a. The quantity of that part of water
depends on a variety of circumstances, such as temperature of the fire-gases, area of
surface of the tubulous boiler b, degree of superheating demanded, and the like; the
cock h is, as a matter of course, adjusted accordingly. Also if the degree of
superheating is to be an extraordinarily high one, a part of the water of condensation
is allowed to run back into the boiler a.
Owing to the circumstances just mentioned, the falls of temperature will in
different cases be different ones, and the numbers given in the above paragraphs are
therefore to be considered as examples only.
In finishing my specification I finally call attention to the fact, that by heating
the feed-water up to about 160° the latter is practically perfectly freed of every-
thing that might tend to incrust the boiler a; by feeding the boiler 6 (apart from
the steam) with water gained out of steam that is generated from that highly
purified water, there is afforded an absolute security against even the slightest
incrustation of said boiler b, and I am therefore enabled to construct the latter of a
continuous series of tubes the diameter of which is but a small one.
Dated this 17th day of December 1895.
WILHELM SCHMIDT,
By Cassell & Co.,
Agents for the Applicant,

page_text: Improvements in and connected with Means for Heating and
Purifying Feed-water for Boilers.
1, WILHELM SCHMIDT, of Ballenstedt on the Harz, in the Duchy of Anhalt,
German Empire, 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 :-
:
This invention refers to a method of highly exhausting the calorific power of
boiler furnace gases on generating steam and purifying feed-water. Said method
is in general characterized by causing steam that is generated within any suitable
type of boiler to give its heat or a part thereof off to feed water (intended either
for the boiler that produced said steam or for another one), so that the said steam
is thereby condensed, or turned into water of condensation respectively; and by
turning said water of condensation or a part thereof again into steam by exposing
it also to boiler furnace gases, preferably to the waste of those afore mentioned.
The steam to be condensed need not be the whole steam produced by the boiler just
employed; and the said water of condensation when exposed to said waste gases
need not form a column or other body of stationary or flowing water, but may, if
desired, be transformed into a state of suspension by aid of steam, as is all more
fully described hereinafter.
There result from the statements afore given a number of different manners of
working, the more important of which are the following:
1. All the steam generated is condensed, and all the water of condensation is
re-turned into steam.
2. A portion only of the steam is condensed, and all the water of condensation
is re-turned into steam;
3. A portion only of the steam is condensed, and all the water of condensation
is re-turned into steam after being suspended within the other portion of the
first-mentioned steam.
4. All the steam generated is condensed, and a part only of the water of
condensation is re-turned into steam;
5. A portion only of the steam is condensed, and a part only of the water of
condensation is re-turned into steam; aud
6. A portion only of the steam is condensed, and a part only of the water of
condensation is re-turned into steam after being suspended within the other portion
of the first-mentioned steam.
By employing my novel method, especially with any of the manners of working
afore enumerated, there is offered a possibility of producing great quantities of dry
or even superheated steam within a boiler of very small dimensions, and with the
consumption of very small quantities of fuel, and the main-boiler as well as the
auxiliary one (within which the water of condensation is re-turned into steam)
remain, moreover, practically free of incrustations.
My invention may be carried into practice by a variety of constructions of
boilers, feed water heaters, superheaters, and the like, and in order to make my
invention more clear, I have shown as examples two forms of construction in the
drawing sent in with Provisional Application, in which similar letters denote
similar parts throughout the different views, and in which:
Figure 1 is a vertical section through a vertical boiler combined with a tubulous
boiler and a feed water heater; and
Figure 2 is a similar view representing a modified arrangement.
The steam-space of the boiler a (Figure 1) is connected by the pipe c with the

page_text: upper end of a coil 9 arranged within the vessel f. The latter together with said
coil form the beating device for the feed-water. The lower end of the said coil is
connected by the pipe e with a tubulous boiler b, which in the form of construction
shown is composed of a column of flat coils forming a continuous way for the
water, or water and steam, passing through them. Said pipe e is connected with
the upper end of said coils, and the water, or water and steam, passing through
them, is or are thus compelled to flow in a direction opposite to that of the fire-
gases, or more precisely to the waste-gases, escaping from the furnace k. I wish
it, however, to be understood, that the connection of the said coils among each
other, and with the pipe e, may well be made in such a manner, that the water, or
water and steam, flows or flow in the same direction as do said waste-gases, or
partly in the same direction, and partly in the reverse one.
The feed water to be heated is led into the vesself through the pipe m, and is
led off in a heated state through the pipe n. Said feed water and the steam that
passes through the coil g flow thus in this case, too, in opposite directions, but I
wish it again to be understood, that I do not limit myself thereto.
In either case,
however, I prefer to arrange the feed water/g in such a height with regard to
the tubulous boiler b, that the water of condensation formed within the coil g may
freely flow over into said boiler 6 without any auxiliary means.
The water contained within the vessel is, as a matter of course, heated by the
steam passing through the coil g. Owing to the great quantities of steam that may
be led through said coil, said water may, in fact, be heated nearly up to the
temperature of the water within the boiler, and those impurities, which later on
might be separated within the boiler by the heat of the latter, and might therefore
contribute to the incrustation of the same, are thus caused to separate before, and
may then easily be caused to precipitate, especially if the vessel ƒ is a suitably
wide one.
The steam generated within the boiler a need not, as a matter of course, all be
caused to pass through the coil g, but a certain part thereof may be led on a
direct way off to the place of use; said part may, however, prior thereto be dried
or superheated, for instance by letting it flow through one or more of the coils of
the tubulous boiler b.
The water of condensation flowing from the pipe e into the coils b is re-heated
within the same, and again turned into steam, and the latter is then either dried
only, or superheated, too.
To exhaust the calorific power of the waste-gases in the highest possible degree,
and also to regulate the degree of superbeating of the steam formed within the
coils b, I prefer to make use of the modified arrangement shown in Figure 2. The
coils are in this case put in direct connection with the steam-space of the boiler a
by means of the pipe d; the pipe c (leading the steam, or more precisely a part
thereof, to the feed-water heating coil g) proceeds from said pipe d, and the pipe e
(leading the water of condensation off the coil g) terminates into the said pipe d
above the commencement of the pipe c. A pipe of somewhat smaller diameter
counects the boiler a with the pipe e, and a cock h arranged at the place of
junction of the pipes i and e allows of letting the water of condensation pass either
wholly to the pipe d, or partly to the latter and partly to the pipe i.
Supposed, the position of the cock / be such a one, that the pipe i is closed, all
the water of condensation formed within the coil g will flow into the pipe d above
the commencement of the pipe c. The steam streaming from the boiler a into said
pipe d divides at said commencement of the pipe c, oue part passing through the
latter into the coil g, and the other part passing directly to the tubulous boiler b.
Said latter part of steam meets, and receives, the water of condensation emanating
from the pipe e, and carries said water with it in a suspended state into said boiler b.
The suspended water is evaporated within the upper coils of the tubulous boiler b,
and the whole quantity of steam thus obtained is first dried within the middle coils,
and then superheated within the lower coils of said boiler.
Owing to the wetness of the steam that passes into the tubulous boiler b, or more

page_text: •
precisely into the upper coils of the latter, the waste-gases the heat of, which has
already been used up to a great measure by the lower and middle coils will now
give off the last part of their useful heat to said upper coils. To attain that bigh
exhaust, the upper coils need not indispensably offer (just by reason of said wetness
of the steam) a very large area of surface, and said high exhaust may thus be
obtained on a comparatively small space.
In order to make the several stages in the transition of the heat (from the fresh
steam to the feed-water, and from the waste-gases to the wet steam) more clear,
I will assume, that the steam generated within the boiler a possesses a pressure of
11 atmospheres, and passes through the pipes d and c with a temperature of
about 180°, and that the feed-water enters the vesself with a temperature
of about 30°. Said water on slowly rising from the pipe m to the pipe n is heated
up to about 150°, whereas the steam will be turned into water of condensation
having a temperature of about 60°. The fall of temperature amounts, therefore,
at the upper end of the coil g to about 30°, and at the lower end of the same to
about 30°, and it is thus to be seen that every part of said coil heats the feed-water
with about the same power.
An equally advantageous fall of temperature is to be found in the furnace gases with
regard to the water and steam flowing in an opposite direction through the coils b.
The steam (having a certain amount of water of condensation suspended within it)
possesses a medium temperature of about 180°, and is first acted on by fire-gases
having a temperature of about 250°, the difference amounting thus to about 70°.
The mixture of water and steam on flowing down within said coils is completely
turned into steam by the fire-gases; that steam is then dried and finally super-
heated, the degree of superheating amounting up to about 300°. The temperature
of the fire-gases acting upon the lowermost coils is about 600°, whereas the
temperature of the gases acting upon the uppermost coils amounts to about 250°.
The fall of temperature of said gases is thus a highly remarkable one, and is in
this magnitude obtained only by letting the steam entering the tubulous boiler b
be very wet.
In case, the quantity of water of condensation be so great that either said water
cannot completely be evaporated within said boiler b, or the steam produced out of
the said water cannot be sufficiently superheated, I let a part of that water run
back through the pipe into the boiler a. The quantity of that part of water
depends on a variety of circumstances, such as temperature of the fire-gases, area
of surface of the tubulous boiler b, degree of superheating demanded, and the like;
the cock h is, as a matter of course, adjusted accordingly. Also if the degree of
superheating is to be an extraordinarily high one, a part of the water of
condensation is allowed to run back into the boiler a.
Owing to the circumstance just mentioned, the falls of temperature will in
different cases be different ones, and the numbers given in the above paragraphs
are therefore to be considered as examples only.
In finishing my specification I finally call attention to the fact, that by heating
the feed-water up to about 160° the latter is practically perfectly freed of
everything that might tend to incrust the boiler a; by feeding the boiler b (apart
from the steam) with water gained out of steam that is generated from that highly
purified water, there is afforded an absolute security against even the slightest
incrustation of said boiler b, and I am therefore enabled to construct the latter of
a continuous series of tubes the diameter of which is but a small one.
Having now particularly described and ascertained the nature of my said inven-
ion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. A method of exhausting the waste-gases of a boiler-furnace, characterized by
letting the steam generated within that part of the boiler which contains the
furnace be condensed by the feed-water whilst heating the latter, and by leading
the water of condensation (may be, mixed with steam) into the other part of the

page_text: boiler which is heated by the waste-gases of said furnace, so as to turn said water
of condensation into steam.
+
2. In the method characterized by Claim 1, the use of a pipe i branching from
the pipe e that leads the water of condensation away, and the employment of a
regulating-device allowing of partly leading the water of condensation off the
steam-pipe d, for the purpose of regulating the degree of superheating.
Dated this 15th day of September 1896.
WILHELM SCHMIDT,
By Cassell & Co.,
22 Glasshouse Street, Regent Street, London, W.,
Agents for the Applicant.