A Method of Applying Auxiliary Heat to Steam Boilers aud Means or Apparatus for Carrying it into Effect.
Year: 1886

page_text: A Method of Applying Auxiliary Heat to Steam Boilers aud
Means or Apparatus for Carrying it into Effect.
I, BENJAMIN JOSEPH BARNARD MILLS of the firm of Harris and Mills of
23 Southampton Buildings in the County of Middlesex, Patent Agent, do hereby
declare the nature of said invention, a communication to me from abroad by
Carl T. Burchardt of Berlin in the Kingdom of Prussia and Empire of Germany.
Engineer, and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:-
In many steam boilers which have a poor water circulation, particularly in those
with interior furnaces, direct and return flues or tubes and therefore more particu-
larly in ships' boilers the water acquires only very slowly a uniform temperature
throughout all its body. Those portions of the water above the furnace and around
the flues or tubes through which pass the gases of combustion take up the heat of
the fire firstly and quickly; those in contact with the sides of the furnace and
below the flues more slowly and to a smaller extent; and finally those below the
ash pit or below the flue plates which are covered with ashes, receive no heat at
all and remain cold, at least for a very long time, until the heat of the adjacent
water, which is a very poor heat conductor is by and by communicated to them.
If the conditions are very unfavorable as for exemple in boilers constructed as:
shown in the accompanying drawings, it may happen that in the upper part S of¹
the boiler the steam pressure amounts to 5 atmospheres and more whilst in the
lower part E the water is still frozen. It is evident that such a state of inequality
in the temperature of different portions of the water, even if it does not reach such
extremes as are just mentioned is very unfavorable for the steam raising quality,
as well as for the durability of the material and of the joints of the boiler as the
expansion and contraction of the plates seams and other parts is an irregular and
destructive and even a dangerous one.
The object of this invention is to remedy these inconveniences and defects
by heating the water more uniformly and in a very simple and inexpensive way,
ID 1
...

page_text: For this purpose those portions of the water which are not heated at all or only
insufficiently by the fire of the usual furnace or furnaces are heated separately by
steam produced either by the boiler itself or by a separate boiler or other contrivance
or by an auxiliary furnace.
And in order the better to explain the invention I will describe some practical
applications of it, by which persons wishing to adopt the same will understand it
more clearly and will be enabled to carry out this new method of the auxiliary
heating of steam boilers affected with defective water heating qualities, without
difficulty and in the manner best adapted to circumstances.
In the accompanying drawings forming part of this specification the same letters
of reference denote similar parts.
The new method of the auxiliary heating of steam boilers by the aid of steam
from the boiler itself is shown in Figures 1 to 6 and an arrangement by which the
auxiliary steam is furnished by an outside separate source is shown in Figures 9
and 10. Figures 7 and 8 however represent an arrangement wherein an auxiliary
furnace is attached directly to the boiler under its lower part for accomplishing the
desired purpose. These exemples only illustrate some of the modes in which the
invention may be carried into effect but they will suffice to explain it and to
suggest in what manner the invention may be applied to boilers of other constructions
and under other conditions than those shown.
Figures 1, 4, 7 and 9 are vertical longitudinal sections of different boilers.
Figures 2, 5, 8 and 10 are vertical cross sections of the same.
Figures 3 and 6 are plans of the lower parts of the two first boilers, showing the
situation and the arrangement of the heating coils or elements.
In the boiler of Figures 1 to 3 the steam for auxiliary heating is taken from a
suitable part of the steam base S after having been produced by the fire upon the
grate g of the furnaces f and carried through the pipes p which run down outside
the boilers to heating coils c in the narrow water space E below the ash pits b of
the furnaces The water condensed in the coils c is carried off by the pipes q and
its flow may be regulated by means of the cocks k as shown or by other suitable
means.
By letting the steam pass through the coils c the water surrounding them is
heated to a degree very near to the temperature of the upper portions of the water
in the boiler. The heating of the lower portions E of the water commences with
the generation of steam in the upper ones and from this moment the difference in
the temperature of these different portions is rapidly diminished until after a short
time it is very nearly equalized, so that the plates, seams tubes and joints of the
boiler are not affected by any irregular and uneven expansion or contraction not
even at the beginning of the firing of the boiler when the extreme difference in the
temperature would amount to very little more than about 100° that is to say in
case the water in the boiler was frozen. The coils c may be constructed in any
suitable and known manner In Figures 1 to 3, coils are used composed of
hollow castings with ribs on the outside forming so called heating elements or
radiators.
In Figures 4 to 6 the pipe carrying the steam from the upper part of the steam
space S down to the coils c in the water space E below the ash pit or ash pits is
situated entirely within the boiler.
The water condensed in the coils c, which are in this case of a different pattern
of radiator than in the boiler described in Figures 1 to 3 is carried off by means of
the cock or valve k and the pipe q.
In Figures 9 and 10 the steam for auxiliary heating is furnished by a so called
"Perkins high pressure furnace" P situated in any convenient place separated from
the boiler. The steam passes from the Perkins furnace P through. pipe p into the
coils c in the lower water portion E of the boiler. The condensed water returns
through pipe q to the coils of the Perkins furnace to be used over again. Instead
of a Perkins furnace the required steam may be taken from any other common
boiler at hand,

page_text: The coils c are shown here as consisting of mere bends of the pipe p itself: but
other systems of coils may be employed.
In Figures 7 and 8 the auxiliary heating of the boiler water is accomplished by
a separate furnace m provided below the boiler and attached directly to it. The
gases of combustion of this auxiliary furnace m are carried by flues n under the
grates g of the furnace or furnaces f of the boiler where they are burned or removed
with those of the main furnace or furnaces f through the smoke stack.
This mode of furnishing the auxiliary heat from a separate source outside the
boiler as illustrated by the arrangements in Figures 7 to 10 has the advantage that
it is not necessary to wait till the working boiler is generating steam but it
also has the disadvantage that it is dependent upon separate arrangements made
expressly and with more or less expense for this purpose.
Having now particularly described and ascertained the nature of the said
invention and given a number of different examples of ways in which it may be
carried into effect I would have it understood that the invention is not dependent
upon the use of the precise devices and constructions shown in the drawings which
may be varied according to circumstances, but what I claim is :-
1. The method of applying auxiliary heat to steam boilers consisting in heating
those portions of the water of the boiler which are not at all, or only insufficiently
heated by the fire of the usual furnace for furnaces either by steam produced by
the boiler itself or by steam from another boiler or other contrivance or by both
combined or by an auxiliary furnace m substantially as herein shown and described
and for the purpose stated.
2. For carrying out the method of the auxiliary heating of steam boilers
protected by claim 1 the employment and use of coils, heating elements or
radiators e placed in those portions of the boiler water which need auxiliary
heating in combination with a pipe p or pipes admitting to them steam from the
boiler itself or from any other source substantially as herein shown and described.
3. For carrying out the method of the auxiliary heating of steam boilers
protected by claim 1 the employment and use of an auxiliary furnace m attached
directly to the boiler in a suitable place, the gases of combustion and the smoke
of which furnace m may be carried off by the main smoke stack or in any other
suitable way substantially as shown and described.