IMPROVEMENTS IN STEAM BOILERS, AND THE FURNACES THEREOF
Year: 1865

page_text: PROVISIONAL SPECIFICATION left by Edward Brown Wilson and James
Howden at the Office of the Commissioners of Patents, with their Petition,
on the 11th March 1865.
We, EDWARD BROWN WILSON and JAMES HOWDEN, both of Glasgow, in the
County of Lanark, North Britain, Engineers, do hereby declare the nature of
the said Invention of "IMPROVEMENTS IN STEAM BOILERS, AND THE FURNACES
THEREOF," to be as follows, that is to say:-
This Invention relates to certain improvements in furnaces and their appli-
cation to the generation of steam in boilers, and also to certain improved
constructions of boilers for land and marine purposes, whereby the combustion
of the fuel is more perfectly effected, and the heat more thoroughly utilized
than heretofore. These improvements in so far as they relate to the manner
in which the fuel and the air for combustion is introduced to the furnaces are
based upon former Letters Patent granted to Edward Brown Wilson, one
being dated 3rd October 1863, and numbered 2425, and another granted
or applied for and dated 16th February 1865, and numbered 443, the fuel
in such furnaces descending through a passage or hopper placed over the
furnace at the outer end, and the air for combustion passing down through the
fuel from the top, no air being allowed to pass up through the fuel by grate
bars or other passages in the usual manner of furnaces as presently constructed.
The improvements in steam boilers under this Invention in their application
to a marine boiler of the horizontal multitubular type consist in carrying the
sole of the ash-pit forward past the front of the boiler and raising therefrom a
rectangular box with front and sides to a distance upwards somewhat beyond

page_text: the usual height of the furnace doors in such boilers. The top or upper side
of this box is open for the admission of the fuel, which is preferred to be filled
so high when working that the mouth of the furnace chamber is covered by
it, the air for combustion passing through the fuel from the top until it reaches
the incandescent fuel lying in an inclined plane, and projecting into the furnace
chamber. The heat then passes along the furnace and returns through the
tubes in its passage to the funnel in the usual manner. This projecting box
part of the boiler, consisting of front, sides, and bottom, contains a water space
of several inches according to the size of the boiler, and is in connection with
the main portion of the boiler, and forms part of its heating and evaporating
surface. The sole of the furnace may either form a water space until it reaches
the back of the boiler, as in what are termed "wet bottom" boilers, or the
water space may terminate somewhat beyond the part whereon the incandescent
fuel lies, the remaining part being made up of brick or iron plates. A small
bridge may be used to prevent the fuel extending beyond a certain distance
from the front. As the heat may be made very intense in furnaces constructed
in this manner, it is proposed to use a lining of fire-brick or other fire-resisting
material in those parts of the combustion chamber where the heat is strongest
in such furnaces where a very rapid combustion is required. We also prefer
to make the furnace top of the main portion of the boiler at its entrance nearly
flat across, to give a more regular automatic admission of the fuel, though the
remaining part of the furnace crowns be semicircular in the usual manner.
In a boiler of 2 or more furnaces a rectangular box combustion chamber as
already described is placed in the front of each furnace, but the front part of
the boxes may be made in one continuous line across the whole boiler, the
separate combustion chambers being portioned off by divisions, either of water
spaces, fire-brick, or other material (water space divisions being preferred),
between the front of box and front of main part of the boiler. In the bottom
part of each combustion chamber a moveable door or doors is placed to allow
the ashes being cleared out when required, such door or doors being closed
air-tight when the furnace is working. Instead of the bottom of the combustion
chamber's being quite level from the front backwards, they may be made some-
what higher at the front part, and then descend nearly perpendicularly to a
lower level, the doors for cleaning being put in the perpendicular part. To
hold a larger quantity of fuel a hopper, not forming a part of the boiler, may
be placed on the mouth of the combustion chamber. The admission of air
may at all times be regulated by a moveable cover or damper on the mouth
of hopper or combustion chamber, which cover or damper may be made self-
acting by the action of the steam in the boiler, though we at the same timo

page_text: use a damper in the chimney, which we may also make self-actiug by the steam
in the boiler.
We also modify the combustion chamber according to this Invention that,
instead of the front part of such chamber being perpendicular or nearly so, as
in the modification previously described, it slopes from the top backwards
towards the bottom, which may reach to about the front of the main part of
the boiler. The arrangements of combustion chambers now described can be
applied to all the ordinary forms of marine boilers, though in the case of a
circular or "haystack" boiler the combustion chambers may either have
their fronts formed straight or concentric to the outside of the main part of
the boiler.
In applying
our Invention to a locomotive or portable engine boiler we close
up the bottom or present fire-grate part of the fire-box (preferring to make it
a water space and part of the boiler), and carry the lower part of the front of
the fire-box further out than the upper part, so as to form the outside part of
the combustion chamber and mouth for the admission of the fuel and air. It
is not, necessary that the feeding mouth be the whole width of inside of fire-
box, it may be shortened either by fire-brick or other material, or by the side
water spaces being made larger.
This Invention is applied to the Cornish land boiler in the same manner as
described, though the circular form of the bottom may still be retained.
In such boilers as are without flues or receive the flame first underneath
it is preferred not to form the combustion chamber with water spaces, but
construct it similarly as described of cast iron (though plate iron may also be
used), and line the inside with a sufficient depth of fire-brick or other material
to withstand the intensity of the heat, and in altering the existing furnaces in
land and marine boilers we may use these cast-iron and brick combustion
chambers without water spaces, and in the boilers of locomotives or portable
engines we propose, after closing up the fire-grate, to cut a rectangular space
or spaces across the front of fire-box (preferred to be above the present fire-
door), and erect a similar chamber or hopper on the outside, inclining in at
its outside part at an angle upwards from the fire-box. In such cases
we confine the combustion of the fuel almost entirely within the present
fire-box of the boiler.
The dimensions of the mouth of the feeding doors of the combustion chambers
described in this Specification vary according to the size and power of the
boiler, and it is not necessary that they should be in every case of the
rectangular form already described.
A modification of an improved steam boiler of the "haystack" kind as used
.

page_text: for steam vessels according to this Invention consists in forming an annular
ring water space in connection with the outside water space of the boiler
directly over the top of the furnace or furnaces or combustion chambers, and
above this annular ring at some distance the central pan part is placed, its
outer periphery lying somewhat over the annular ring. A few water tubes may
extend from the annular ring and central pan to the inner dome of the boiler,
but these may also be dispensed with. The flame from the furnace is thrown
well in towards the centre by the annular ring, and then in its ascent strikes
against the under side of the central pan, and filling the chamber above this,
passes up through the water and steam space of the boiler through a number
of tubes to the funnel. The central pan is united to the water space of the
upper part of the boiler by one or more large tubes, and we prefer also to
have the usual connecting cross water spaces between the central pan and
sides of the boiler.
This boiler may also be modified so that the usual water tubes extending
from the crown of the central pan to the inside dome of the boiler may be
used with the annular ring water space, a passage sufficient to permit of
admission for cleaning the outside of the tubes being left between the annular
ring and central pan, though we can state that boilers constructed as herein
specified require very little cleaning, the fuel being thoroughly consumed in
the furnace, and consequently preventing the ascent of any carbonaceous gases
through the boiler. As the quantity of fuel consumed is also very much less
than in other boilers, we proportion the calorimeter or area of passages for
the exit of the heated products of combustion accordingly, so that the greatest
possible economy of fuel is obtained.