Improvements in and connected with Heating Feedwater for Steam Generators.
Year: 1892

page_text: Date of Application, 26th July, 1892-Accepted. 27th Aug., 1892
Improvements in and connected with Heating Feedwater for Steam
Generators.
I. CASSIUS CARROLL PECK, of Warsaw, in the County of Wyoming, State of
New York. U.S.A. Mechanical 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:-
My invention relates especially to systems and apparatus in which surface
condensers are used in conjunction with the engines, the water of condensation
being returned to the boiler.
I am fully aware that heaters have heretofore been arranged to purify feed
water by bringing it in direct contact with live steam from the boiler and I do not
seek to cover the direct use of live steam in this connection broadly. I am also
aware that nearly all engines have feed water heaters attached for utilizing the
exhaust steam and that in some cases the water of condensation formed in the
heaters is added to the feed water, but these old contrivances do not anticipate
my invention, and in fact I expressly avoid and disclaim the feature of com-
bining the fresh water with the water of condensation, as well as all idea of
purifying the water returned to the boiler, an essential feature of my invention
being the return of practically all the steam of the boiler by its condensation
in a surface condenser and the heating of the water of condensation to practically
the same temperature as that of the water in the boiler preparatory to adding it
thereto.
Since the feed water required for a boiler would serve ordinarily to condense only
from one-sixth to one-fifth of the weight of steam generated in the boiler (provided
the feed water were cold to start with) it follows that five-sixths of the water to be
pumped into the boiler would have to be fresh water requiring purification, as in
devices heretofore known in which the purification of the fresh water is the object
sought to be obtained.
In my improved system of generating steam no provision is made or designed'
for heating fresh feed water, the invention relating solely to the re-heating of the
water of condensation from the surface condenser in such manner as to obtain the
greatest efficiency with the least expenditure of heat. 1 employ a surface
condenser requiring about twenty-five pounds of cool condensing water for every
pound of steam to be condensed. The introduction of fresh feed water into my
system would soon impair the results and soon render the apparatus inoperative
by reason of incrustation; and on the other hand the object of my invention cannot
be attained by the use of the apparatus heretofore known and designed for the
purification of fresh feed water.
It will thus be seen that my invention is limited to, and restricted by, the use of
a surface condenser in conjunction with means for heating the water of condensation
therefrom up to the temperature of the water in the boiler by the use of live steam
derived directly therefrom.
Heretofore, when surface condensers have been employed, as with marine
engines in connection with which they are practically indispensable the water of
condensation has been pumped directly from the surface condenser, or the hot well
into which it flows from the condenser, into the boiler at a temperature of, say,
about 120° Fah. The boiling point of water in the boiler being determined by the
pressure of steam carried, it follows that the water of condensation thus deliveret
into the boiler cannot boil until heated to the temperature corresponding with the
pressure. Thus when water at 120° F., is pumped into a boiler carrying say 160 lbs.
of steam pressure it cannot boil until heated to 370° F., or 250° above that at

page_text: which it is introduced into the boiler. When thus pumped into the boiler the
water of condensation gradually mingles with the boiler water, reducing the
temperature of the latter below the boiling point and checking evaporation until
the resulting admixture of boiler water and water of condensation is again heated
to the boiling point.
The water in the boiler is expanded by the heat, becoming lighter and limpid,
so that its particles move more freely among themselves, thus creating a more
rapid circulation. As the temperature rises the internal currents, by which the
heat is carried off from the heating surfaces, become more rapid and correspondingly
more heat is carried away from said surfaces. After the water commences to boil
the buoyant steam bubbles, rising through the mass of liquid greatly assists in
increasing the circulation, thus causing the heat to be carried away, or wiped off,
from the heating surfaces with the greatest attainable rapidity.
It will thus be seen that it is desirable to maintain the whole body of water
in the boiler in a continuous state of ebullition in order to attain and maintain
the most effective conditions, since heat can be transmitted to the water at about
three times the rapidity while evaporation in the form of boiling is going on as
compared with the same water while being heated to the boiling point.
My invention consists essentially in condensing practically all the exhaust
steam, after it has performed its work in the engine in a surface condenser in
which condensation is effected by an independent supply of condensing liquid
separated from, and having no connection with, the steam or water of condensation
and then reheating the water of condensation from the surface condenser to, or
approximating, the temperature of the water in the boiler preparatory to its
introduction into the latter by means of live steam taken directly from the boiler,
the water of condensation from the live steam being also returned directly to the
boiler, so that in operation a perfectly uniform unvarying temperature is maintained
within the boiler, and the generation of steam is continuous and unvarying, and not
subject to the fluctuations or interruptions that would otherwise be occasioned by
the return of the water of condensation. It may not at first thought seem that
there can be any gain in this procedure as compared with the old method of
pumping the water of condensation directly into the boiler, but I have discovered
and demonstrated that by method of equalizing or nearly equalizing the temperatures
of the boiler water and water of condensation prior to uniting them in the boiler I
am enabled to materially augment the amount of evaporation which can be effected
in said boiler with a given amount of fuel.
In order to realize the value and importance of this feature of raising the
temperature of the water of condensation prior to its incorporation with that in
the boiler, it must be understood that the gain in the transmission of heat herein-
before intimated is equivalent to about three to one; that is to say, heat can be
transmitted to water at about three times the rapidity while evaporation in the
form of boiling is going on as compared with water which is being heated up to
the boiling point. This is equivalent to saying that a boiler should not be used to
heat the water of condensation directly by the injection of the water of condensation
into the boiler water, since a given amount of boiler surface is worth about three
times as much for evaporation as for heating. There is also a further important
feature worthy of consideration, which contributes largely to the efficiency of my
invention and that is the fact that the independent heater for the water of con-
densation will not require as much surface as the boiler to transmit a given amount
of heat, since the boiler surfaces are heated by direct contact with the products of
combustion while the heater receives its supply of heat from steam from the boiler,
the steam heated surfaces being nearly three times as effective as the gas heated
surfaces.
As a result of my invention the amount of boiler surface for a given effective
power may be reduced about one-fourth, or boilers of a given size increased pro-
portionately in efficiency, as for instance in the case of marine boilers, in which
case the steaming capacity of a steamship could be augmented about one-fourth by

page_text: the employment of my system of treating the water of condensation in conjunction
with the present boilers in use.
An incidental but important advantage attained by my system of equalizing the
temperature of the water of condensation and the boiler water preparatory to
mixing them, is the increased durability or life of the boiler owing to the uniformity
of temperature and circulation maintained,--thereby obviating unequal expansion
and contraction and the consequent straining and weakening of the parts.
by keeping the whole body of water in the boiler it nearly equal temperature
throughout overcome one of the most objectionable causes of injury to boilers
especially to marine boilers and those of large size.
Thus
In the accompanying drawings I illustrate three arrangements of parts adapted
for use in carrying out my invention, each modification operating in substantially
the same manner in use. I do not confine myself to any special construction of
heater, nor to the exact arrangement of the parts shown since it is obvious that
various modifications may be made therein without departing from the essential
features of my invention.
Figure 1, is a sectional elevation representing diagrammatically the combination
and arrangement of a special form of heater for the water of condensation in
conjunction with a condensing engine and a steam boiler, pumps &c. ;
Figure 2, a similar view in which an ordinary form of steam surface condenser
is used as a heater for the water of condensation ;
Figure 3, a similar view in which a horizontal form of heater is used.
A, represents any ordinary or desirable form of steam boiler, supplying steam
through supply pipe a, to the steam engine B. The exhaust steam from the latter
is conducted by the pipe, to the surface condenser C, provided with hot well c.
From the hot well c, the condensed steam is forced by the pump D, through the
pipe d, into the heater E.
In
The heater E, is supplied by pipe f, with live steam from the boiler A.
Figure 2, the steam enters a compartment e', in the heater E, through which pass
the tubes, opening into the end compartments e³, e'. The water of condensation
enters one of these compartments (e³) and passes through the tubes e² to the
other (e), from which it is conducted by the pipe e back to the boiler A. During
the passage of the water of condensation through the tubes e, of the heater E, it
absorbs heat from the steam in the compartiment e', condensing the steam therein,
which condensed steam is returned to the boiler through the pipe e. Check
valves e',, are interposed in the pipes e³, e.
In Figure 3, the water of condensation passes from the pipe d. of the heater E,
around the pipes d³, and out through the pipe 3, to the boiler A. The steam
from the boiler A, enters the end compartment a², of the heater through the pipe
a³, passes through the pipes 2, is condensed and enters the other end compart-
ment a, from which it is returned by the pipe a, to the boiler. Suitable
valves a, a, a, are interposed in the pipes d, a³, and a.
In Figure 1, instead of imparting the heat to the water of condensation in the
heater E, by surface condensation of steam, as in Figure 2, and 3, 1 inject the
steam directly into the body of the water of condensation. In this case the water
of condensation is forced from the hot well e, by the pump D, through the pipe d,
into the lower portion of the heater E. The lower portion of the heater is divided
from the upper by a perforated partition, below which it is filled with gravel &c.
in which a perforated steam chamber, is imbedded. Live steam is conducted
from the boiler A, by the pipe f, to the steam chamber f¹, by which it is dis-
tributed radially to the water of condensation which condenses it and absorbs its
excess of heat. The combined water of condensation from the hot well and the
steam thus condensed in heating it is then returned to the boiler A, through the
medium of pipe g, force pump G, and injection pipe . Steam to operate
the pump G, may be drawn from the upper part of the "heater E, or from the
boiler A, direct if preferred, but there must be somewhat less pressure in heater E,
The exhaust steam from
to permit steam from the boiler to enter the heater.

page_text: the force pump G, is preferably conducted through the pipe g, to the
condenser C.
Regulating valves are arranged in the pipes g³, and f³.
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 I
claim is,
First. The process herein set forth of attaining increased efficiency in the
generation of steam, consisting in generating steam of a prescribed pressure and
temperature in a suitable generator, utilizing the energy of the steam in a suitable
motor, condensing the exhausted steam by an independent supply of condensing
liquid having no direct contact with the exhaust steam or its water of condensation
heating the water of condensation thus obtained, to, or approximating, the
temperature of the water remaining in the steam generated by means of live steam
derived therefrom, and returning the said heated water of condensation together
with the steam condensed in equalizing the temperature thereof, back to the body
of water contained in the generator to be reconverted into steam.
Secondly. The combination of a steam generator, a motor operated by the
steam from said generator, a surface condenser arranged to condense the exhaust
steam from said motor by means of an independent supply of condensing liquid
having no direct contact with the steam or water of condensation, means for
conveying the water of condensation from said surface condenser to a heater, said
heater arranged to heat the water of condensation to or approximating the
temperature of the water remaining in the steam generator by means of live steam
derived directly therefrom, and means for returning the heated water of con-
densation and the steam condensed in equalizing the temperature thereof, back to
the body of water contained in the generator, for the purpose and substantially in
the manner set forth.
Dated this 18th day of July 1892
H. D. FITZPATRICK,
70, Wellington Street, Glasgow, Agent.