Improvements in Steam Boilers and Boiler Furnaces.
Year: 1894

page_text: Date of Application, 11th June, 1894-Accepted, 28th July, 1894
COMPLETE SPECIFICATION.
Improvements in Steam Boilers and Boiler Furnaces.
I, JAMES WALKER, of Tayport, Fifeshire, 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:-
This invention which relates to steam boilers and boiler furnaces has for its
objects to obtain greater efficiency of such boilers by the adoption of a furnace
placed outwith the boiler in conjunction with the use of a fire bridge through which
highly superheated steam is ejected and to adapt the furnace for burning inferior
fuel by the provision of suitable facilities for cleaning and refiring a part of the
fire grate whilst the fire is maintained in another part.
In the accompanying drawings which illustrate the invention Figure 1 is a
sectional front elevation of the boiler and furnace, Figure 2 a longitudinal vertical
section, Figure 3 a horizontal section, and Figure 4 a plan of the same.
The boiler A is or may be of the ordinary Cornish or Lancashire type having
two or more flues B, B' but containing no furnace or fire grate, the furnace C being
situated outwith and in front of the boiler and connected to one of the flues.
The furnace is composed of a chamber C of brickwork or lined with brickwork
in which is supported a fire grate D at or near the level of the bottom of the flue B
the furnace being connected to the boiler front so that the fire gases pass directly
from the fire grate into the flue B and impinge upon a fire bridge E secured at the
mouth of the flue or at the rear of the furnace. This fire bridge is composed of
an iron block E into which there is cast a coil of small piping or through which a
passage is cored for the purpose of conveying steam from the boiler and discharging
it, after it has become highly superheated by the action of the flame upon the bridge,
through orifices e to meet the flame when passing over the bridge. The superheated
steam issuing from the orifices e is decomposed and ensures the complete
combustion of the fire gases and prevents the formation of smoke.
The products of combustion pass over the bridge E and traverse the boiler
flue B and on reaching its extreme end enter a brickwork passage F through which
they are directed into the second or return flue B', and after traversing this flue
they diverge downwards through a brickwork passage G alongside the furnace and
enter the usual flues formed in the boiler setting and distribute the heat over the
lower portion of the boiler shell before passing to the chimney.
Instead of being fired from the front, the furnace is provided with two or more
firing doors H in the side. This arrangement permits not only of evenly
distributing the fuel over the fire grate but of cleaning out or withdrawing part of
the fire and recharging the cleaned part of the fire grate so as to allow time for the
fresh fuel becoming properly kindled before cleaning out or withdrawing the
remaining part of the fire. The inconvenience of having to rekindle the fire after
the cleaning operation, which is incidental to the use of certain classes of inferior
fuel, is thus obviated.
By the arrangement of the furnace outwith the boiler flues the grate area may
be altered or increased relatively to the heating surface, and the full area of the
flues may be utilized as heating surface whilst the ash, which in the usual furnace
flues settles at the back of the flue, remains in front of the bridge and may
conveniently be removed by the side door H.
A feed water heater is or may be provided consisting of a series of pipes I placed
immediately over the furnace and partially forming its crown so as to absorb the
heat which would otherwise radiate therefrom.

page_text: 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 1
claim is-
1. A steam boiler and furnace constructed, arranged and combined substancially
as hereinbefore described with reference to the annexed drawings.
2. The combination with a steam boiler having its heating furnace outwith the
flues of a fire bridge placed in the flue entrance and having carried through it a
coil of piping or a tortuous passage for steam which is superheated therein and
discharged therefrom to meet the flame from the furnace substantially as described
with reference to the drawings annexed.
3. A boiler furnace built outwith but communicating with the boiler flue having
two or more doors provided in its side substantially as and for the purpose set
forth.
Dated this 9th day of June 1894.
CRUIKSHANK & FAIRWEATHER,
62, St. Vincent Street, Glasgow, Agents.