IMPROVEMENTS IN COMPOUND BOILERS OR APPARATUS FOR HEATING WATER AND GENERATING STEAM
Year: 1885

page_text: I, EBENEZER KEMP, of Linthouse 'Shipbuilding and Engineering Works, Govan,
in the County of Renfrew, North Britain, Engineer, do hereby declare the nature
of my said invention for "IMPROVEMENTS IN COMPOUND BOILERS OR APPARATUS
FOR HEATING WATER AND GENERATING STEAM," and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement, that is to say:-
My said Invention has for its object the raising or generating of steam for
motive-power purposes in an improved and very economical manner.
My Invention may be carried out by combining any suitable kind of high-
temperature boiler, of either the fire-tube or water-tube type, with any suitable
kind of low-temperature boiler, of either the water-tube or fire-tube type;
I however prefer to combine a high-temperature fire-tube boiler with a low-
temperature water-tube boiler, the latter consisting of water-tubes connected to
casings and placed in the uptake or otherwise situated so as to be acted on by the
fire gases after these gases have acted on the high-temperature boiler in which the
steam is generated. The water tubes are arranged in groups and so that each
portion of the water passes in succession through several tubes, and has its
temperature greatly raised before reaching the high-temperature boiler. The
heating surface of the high-temperature boiler is made comparatively small and
the water passing through the low-temperature boiler, absorbs a large portion of
heat from the fire gases after they have acted to a certain extent in producing
steam. The arrangements are such that the waste fire gases ultimately pass off at
a considerably lower temperature than is the case in many existing boilers; and
I still further utilise the heat of the fire gases by causing them, after acting on the
low-temperature, boiler, to act on tubes through which is passed the air supplied
to the furnaces, such tubes being by preference arranged like those of the low-
temperature boiler. If it is found that the low-temperature boiler and air-heating
apparatus cause too great a resistance to the current of air and fire gases when
such current is due to ordinary draught only, I employ steam jets or blowing or
exhausting apparatus of any suitable kind to insure the passage of the proper
quantity of air through the furnaces,

page_text: And in order that my said Invention and the manner of performing the same
may be properly understood I hereunto append three sheets of explanatory
drawings to be hereinafter referred to and showing the application of my improve-
ments to various kinds of marine boilers.
Figures, 1, and 2, on sheet, 1, of the accompanying drawings are vertical sections
as at right angles to each other of one modification of my compound boilers, the
lower part of figure, 1, showing part of the high-temperature boiler in front end
elevation at the left-hand side of the figure, and in section through the furnace and
fire tubes at the right-hand side. Figure, 3, is a horizontal section of the low-
temperature boiler. Figure, 4, on sheet, 2, is a side elevation showing the
application of my improvements to boilers with furnaces at opposite ends;
figure, 5, is a sectional side elevation showing a modified arrangement of the tubes
of the low-temperature boiler. Figure, 6, on sheet, 3, is a side elevation showing
the combination of my low-temperature boiler with a high-temperature boiler of
the admiralty type; and figure, 7, is a side elevation showing the combination of
my low-temperature boiler with a (marine) boiler of the locomotive type. In these
drawings the same reference letters and numerals are used to mark the same or
like parts wherever they are repeated.
In the modification shown on sheet, 1, of the drawings the high-temperature
part, HT, of the compound boiler is constructed like a common kind of marine
boiler, and has a main cylindrical shell, 11, with two internal furnaces, 12, having
combustion chambers, 13, at their inner ends, and with fire tubes, 14, through which
the fire gases pass from the combustion chambers, 13, to a smoke box, 15, at the
front end. Between the smoke box, 15, and the funnel or top of the uptake, 16,
a much larger space than usual is enclosed, and the lower part of this space is
occupied by horizontal water tubes, 17, forming the principal part of the low-
temperature boiler, LT, whilst the upper part of the space is occupied by air
tubes, 18.
The water tubes, 17, have their ends fixed in casings consisting of tube plates, 19,
to which are bolted a number of rectangular, covers, 20, made with spaces on their
inner sides, which spaces are separated by ribs or partitions. These spaces in the
casing covers, 20, are arranged so as to direct the water, in succession through
different groups of the tubes, 17. Thus the water, being forced in by feed pumps
in the usual way, enters by a pipe, 21; communicating with one of the top casing
covers, 20, and passes through a section of a number of tubes covered by that cover,
returning through another section of the tubes and proceeding through the
remaining sections alternately in opposite directions. A bent pipe, 22, then leads
the water to the next casing cover and it traverses the tubes appertaining to that
cover in the same manner as in the case of those appertaining to the first cover.
All the tubes are traversed in a similar manner, group after group in succession, the
water being led by bent pipes, 22, from one casing cover, 20, to the next. In the
modification shown in the drawings the water passes first through the uppermost
groups of tubes, 17, and then in succession through the lower groups, this arrange-
ment being preferable as with it the water as it gradually becomes hotter is acted
upon by the hotter fire gases. From the lowest and last group of tubes, 17, the
water is led by a pipe, 23, to the high-temperature boiler, HT, through a check
valve, 24. For the purpose of cleaning the outsides of the water tubes, 17, steam
jets are employed a number of small pipes, 25, made with perforations and supplied
with steam being inserted across various parts of the low-temperature boiler, L T.
As there is a larger space between the rows of water tubes, 17, at the middle, a
blocking piece, 26, is introduced into it to prevent the fire gases from passing too
freely up that way instead of going amongst the tubes.
The air tubes, 18, are arranged in a generally similar manner to the water
tubes, 17, being fixed in end casings, 27, into the upper part of which the air is led
by a pipe, 28. The casings, 27, are divided internally by partitions which cause
the air to pass in succession through different groups of the tubes, 18, the air finally
proceeding by a pipe, 29, to the furnaces. The air heating apparatus does not form

page_text: an essential feature of my Invention and may be dispensed with if desired, at the
same time I believe that its use will increase the economy of fuel.
The high-temperature boiler, H T, shown in figure, 4, is of the double-ended
class with furnaces, 12, and smoke boxes, 15, at opposite ends, the furnaces com-
municating with central combustion chambers. In this modification a low-
temperature boiler, L T, is placed above each smoke box, 15, and is shown as
without air heating apparatus.
The modification shown in figure, 5, differs from that shown in figures, 1, 2
and 3, in having the water tubes, 17, of the low-temperature boiler, LT, placed at
right angles to those of the first modification, and in being without the air beating
apparatus.
Figures, 6, and 7, simply show well known varieties of boilers combined as high-
teinperature boilers with my low-temperature boiler.
My compound arrangement of boiler can be advantageously used with moderate
pressures of steam, it will however be of especial advantage in cases where a
comparatively high pressure is required, such as 150 to 200 pounds per square inch.
For producing a given amount of steam the high-pressure boiler of my system may
be made of comparatively small diameter and will not require plates of objectionable
thickness; whilst the more complete utilisation of the heat of the fire gases will
result in great economy of fuel. The ratio of the heating surface of the low-
temperature boiler to that of the high-temperature boiler may be varied in different
cases, but I prefer to construct the low-temperature boiler with a greater extent of
heating surface than the high-temperature boiler.
Compound or high-and-low-temperature boilers, may be constructed according to
my improved system for land purposes as well as for marine purposes.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what
I-claim is
1-The construction of compound or high-and-low-temperature boilers substan-
tially as and for the purposes herein before described and as shown in the accom-
panying drawings.
2 The combination of boilers or parts of boilers working together and arranged
so that the part in which steam is formed is subjected to a higher temperature than
the part, through which the water is first passed, and the heating surface of which
latter part is equal to or greater than that of the part in which steam is formed
substantially as herein before described.
3-The combination in a compound boiler, or set of boilers, of a part in which
steam is formed and which is subjected to a relatively high-temperature, of a part
through which the water is first passed and which is subjected to a lower
temperature and of a part through which air is passed and which is subjected to a
still lower temperature substantially as hereinbefore described.
Dated this malfth Ja of 007
EDMUND HUNT,
Applicant's Agent.