Year: 1887

page_text: Date of Application, 21st May, 1887
Complete Left, 21st Mar., 1888
Complete Accepted, 18th May, 1888
We JOHN SMITH of 49 Lime Street in the City of London, Engineer, and
DEMETRIUS COWAN of 92 Lewisham High Road in the County of Kent, Merchant,
do hereby declare the nature of this invention to be as follows:-
:-
This invention has for its object increasing the heating surface and improving
the combustion in land and marine steam generators whereby economy in fuel is
effected.
Our improved steam generator which may be of cylindrical or other contour but by
preference cylindrical, is provided with one or more internal furnaces extending
fongitudinally from front to back, and with one or more return flues extending from
back to front. At the front of the boiler an ascending flue is constructed through
which the front end of the furnaces are continued they being fitted with the usual fire
doors.
Into the lower end of this ascending flue opens the front end of the return flue or
flues the rear end of which as well as the rear end of the furnace or furnaces opens
direct into a lower combustion chamber at the back common thereto. The upper
portion of the front ascending flue communicates direct with an upper series of tubes
which traverse the water space of the boiler and open into an upper combustion
chamber at the back, this chamber being separated from the lower one by an inter-
mediate water space or chamber provided or not with cross tubes and so inclined or
curved as that the flame and heated products of combustion shall impinge directly
thereon on entering the combustion chambers whether from the furnace direct, or
from the upper group of tubes. The products of combustion pass first from the lower
combustion chamber along the main return flue or flues to the front ascending flue
and then retraverse the entire length of the boiler along the upper series of tubes to
upper combustion chamber whence they finally issue by the chimney or up take.
It will thus be seen that the products of combustion must traverse the entire length of
the boiler twice before they finally escape. In practice we prefer to employ two
internal furnaces disposed longitudinally and parallel to each other and a single return
flue situate between them and at a lower level. Or this single main return flue may
be replaced by a lower group of tubes if desired. An air inlet fitted with any suitable
the
[Price 8d1

page_text: or well known regulator is provided in the back of the lower combustion chamber
opposite the mouth of the main return flue for the purpose of admitting fresh air into
and amongst the products of combustion as they enter the said flue whereby the com-
bustion is improved. Groups of fire tubes are also disposed alongside the furnaces
and like them communicate between the lower combustion chamber and the front
ascending flue these tubes taking a portion of the returning products of combustion
into the said front flue. The water space or chamber which divides the upper from
the lower combustion chamber may extend either entirely or only partly from side
to side of the said chambers.
In the latter case the division is completed by hinged metal side flaps which when
closed in their normal position rest upon the two edges of the water chamber but can
be turned up or opened so as to leave a free direct communication between the lower
and upper combustion chambers should the upper set of tubes get out of order from
leakage or other cause in which case the boiler can be worked in the usual way
without using the return flues or tubes.
.
EDWIN P. ALEXANDER, Fel. Inst. P.A.,
Agent for the Applicants.

page_text: Improvements in Steam Generators.
We, JOHN SMITH, of 49 Lime Street, City of London, E.C., Engineer, and
DEMETRIUS COWAN, of 92 Lewisham High Road, Surrey, Merchant do hereby
declare the nature of our said invention, 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 :-
Our invention relates to improvements in steam generators, and has for its object
the production of a steam boiler or generator of large heating surface, and in which
steam is generated more rapidly than hitherto, while at the same time fuel is
economized, and a perfect circulation, and even temperature of water ensured.
This our invention consists essentially in the combination and arrangement of tubes
and flues whereby a double return of the flame and heated gases from the furnace is
obtained, and the area acted upon by such flame and gases considerably increased.
A thorough absorption of all the gases before they reach the uptake or chimney is
ensured, and thus a great saving of fuel is obtained, as compared with the ordinary
boiler, in which latter such gases pass away at a very high temperature, over 600° F.
And in order that this our invention may be fully understood reference is had to
the accompanying drawings and to the letters of reference marked thereon. Figure 1
is a longitudinal sectional elevation through line X Y of Fig. 2 of a boiler or generator
constructed in accordance with this invention, and Figure 2 is a cross section of the
same, the right hand side of which represents the front end of boiler, and the left
hand side the back or after end, and particularly shewing the division chamber K
hereinafter referred to. Figure 3 is a longitudinal section of a boiler also constructed
in accordance with this our invention, but in which the arrangement of after end
differs from that shewn in Figure 1, and in which the division chamber and uptake
are of somewhat different form. A A are the furnaces, B is the combustion chamber,
Ca lower combustion chamber or flue, D D are tubes for the passage of flames and
heated gases, E is a flue in front of boiler, F F is a collar in front of furnace,
supported by angle irons ff, and serving to divide the furnace from the flue G G are
an upper series or nest of tubes for the passage of flames and heated gases. H is an
upper combustion chamber and I the uptake. K is a division chamber, preferably
having a water space, and extending across the boiler to within say about 18 inches
on each side of combustion chamber. This division chamber may be either formed
as shewn in figure 1 viz :-truly circular, or it may be formed at any angle to the
back of boiler, such as shewn for instance in Figure 3. When fitted at an angle and
with upper combustion chamber and uptake as shewn in Figure 3, we prefer to fit a
lifting door L (shewn in dotted lines) which may be either of brick or iron. A
spindle M to which this door is attached passes through the outer shell of boiler, and
there it has a lever attached which may reach to the front or any convenient part so
that the door may be raised, and admit of an easy entrance to the upper series of

page_text: tubes. It may also be opened whilst lighting up for a clean blow through the funnel
or chimney shaft. N is an aperture for the admission of oxygen for the purpose of
ensuring complete combustion, and when required, through which a forced draught
may be introduced into the lower combustion chamber or flue C. This latter chamber
or flue may also be used in combination with asbestos rock for using oils, the spray
being admitted through the aperture N. The number, shape, & size, of the tubes
together with their distances apart may be varied to suit requirements, a convenient
arrangement is that the area of the upper nest or series of tubes should equal that
of 1 furnace; and that of the lower nest of tubes combined with the bottom flue,
should also equal the area of 1 furnace. The flames and heated gases pass from the
furnaces A into combustion chamber B at back, they then return through lower
flue C and lower nest of tubes D, into flue E in front of boiler, pass around collar F
and thence rise and enter the upper series of tubes G which they traverse, and pass
into upper chamber H and away through uptake I.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed we declare that what we
claim is :-
1. In steam generators the combination and arrangement of the two series or
nests of tubes D and G, lower flue C, combustion and division chambers B and K,
for the purpose of obtaining a double return of the flame and heated gases, sub-
stantially as hereinbefore set forth.
2. The construction and arrangement of door L in chamber at back of boiler for
easily getting at the tubes, substantially as described and shewn with reference to
Figure 3.
3. The general construction and arrangement of steam generators, substantially as
and for the purposes herein before set forth and described with reference to the
accompanying drawings.