Invention for Improved Construction of Furnaces and Closed Fires.
Year: 1887

page_text: Date of Application, 11th Feb., 1887
Complete Left, 11th Nov., 1887
Complete Accepted, 16th Dec., 1887
PROVISIONAL SPECIFICATION.
Invention for Improved Construction of Furnaces and Closed Fires.
I CHRISTOPHER JOHNSON of South Hetton Colliery in the County of Durham Store
Keeper, do hereby declare the nature of this invention to be as follows:-
It consists
An invention for improved construction of Furnaces and closed fires.
of a partition or Diaphragm D1 and D2 placed in the furnace B at the back of the
hearth B', which partition may be in a vertical, inclined or curved position, and
extends from the roof to the bottom of the furnace, with openings at or near the
bottom, through which the products of combustion pass from the hearth B¹ into a
chamber behind, i.e. the combustion Chamber E. There are also one or more
openings F. at or near the top of the diaphragm or partition, which communicate with the
combustion chamber E. at or near the bottom of the partition D & D³. These
openings are fitted with Valves or dampers, V, for regulating the quantity of air for
combustion. The smoke and other unconsumed gases which escape from the fuel in
the furnace are conveyed (together with a supply of fresh air from the front of the
furnace, past the damper V down the Flue F.) and as they meet the products of
combustion passing from the Furnace B. through the opening at the bottom of the
diaphragm D. they are themselves consumed, and so produce greater heat in the coin-
bustion chamber E. from which the required heat is communicated to the Boiler, Still,
Crucible or other vessel which is fixed over, in or against the Flue G.
The partition or Diaphragm D' & D² may be of Metal, Fire Clay or other
refractory material, or may be partly of one and partly of another of these materials,
and may be solid or hollow.
The hearth B' of the furnace may be horizontal or inclined, and may be constructed
of Fire Clay or Metal, or partly of Fire Clay and partly of Metal, and may be either
perforated or solid.
Where the hearth is perforated, the space C beneath the Furnace Bis fitted with
doors C, for the regulation of air to the furnace.
The heat in the combustion chamber E may be supplied either by one furnace only,
or any number of furnaces made to communicate with it, according to the quantity of
beat required, and the use to which it is to be applied.
The invention may be applied to Furnaces of Stationary, Locomotive, or Marine

page_text: Boilers, for Heating Stoves or Kilns of every description, and for Stills and any other
Manufacture or process in which great and regular heat has to be created in closed
fire places.
The object of this invention is to ensure a larger proportion of the heat contained
in the fuel being transmitted to the combustion Chamber than can be obtained by
furnaces now in use, as well as to reduce the labour of stoking.
The results are that greater heat is obtained from any fuel used. That Duff, Slack,
Breeze or anything of a carbonacious character can be burnt; that there is a complete
combustion of all volatile hydro-carbons and solid carbon, and only incombustible
matter is left; that smoke does not pass beyond the combustion chamber, or into the
Chimney, and that the temperature is not diminished by the admission of cold air, as
in the caso of ordinary furnaces.
CHRISTOPHER JOHNSON.
COMPLETE SPECIFICATION.
Improved Construction of Furnaces and Closed Fires.
I CHRISTOPHER JOHNSON of South Hetton Colliery in the County of Durham,
Storekeeper, 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 has for its object to so construct and arrange furnaces and the parts
connected therewith that practically perfect combustion is ensured whereby the
maximum evaporative efficiency is obtained from the fuel employed.
The invention consists in the use of and application to or combination with furnaces
and closed fires and combustion chambers of an improved arrangement for admitting
air as required to effect the above purpose.
The advantages gained by my improved construction are that greater heat and
evaporative efficiency are obtained from any description of fuel used that duff, slack,
breeze or anything of a carbonacious character can be burnt; that there is a complete
combustion of all volatile hydro carbons and solid carbon, and only incombustible
matter is left; that smoke does not pass beyond the combustion chainber or into the
chimney, and that the temperature is not diminished by the admission of cold air as
is usually the case in ordinary furnaces.
The invention may be applied to furnaces of stationary, locomotive, or marine
boilers for heating stoves or kilns of every description, and for stills and any other
manufacture or process in which great and regular heat has to be created in closed
fire places.

page_text: According to this invention one or any desired number of furnaces may be
employed according to the degree of heat required.
I will first fully describe my invention in reference to an arrangement of four
furnaces.
This is illustrated in sheets 1 and 2 of the accompanying drawings in which
Figure 1 is a sectional plan on line ab of figure 2; Figure 2 is a complete vertical
section on line c d of figure 1; Figure 3 is a side elevation of figure 2; Figure 4
is a complete section on line e. f. of figure 1. An arrangement of two furnaces is
illustrated in sheet 3; Figure 5 is a sectional plan; Figure 6 is a half front elevation
and half cross section on line g h figure 5; and Figure 7 is a section on line ij
figure 5.
In all these figures like letters represent like parts.
B B are furnaces entirely enclosed in brickwork except at the front, which may or
may not be provided with firedoors. The hearth B of the furnace may be
horizontal or inclined and may be constructed of fire clay or metal or partly of fire
clay and partly of metal and may be either perforated or solid.
Where the hearth is perforated the ashpit C beneath the furnace B is fitted with
doors with or without the usual adjustable air inlets for the regulation of air
admission to the furnace. Between each furnace and its combustion chamber I
provide a diaphragm D1 D2 containing an intermediate aperture or flue F. The
diaphragm may be of metal, firebrick, or other refractory material or partly of metal,
and partly of firebrick and may be solid or hollow, i.e. the parts containing the flue
may be hollow as for example when made of metal, in which case I may use the
enclosed spaces as water or air spaces. The diaphragm may be arranged in a vertical
inclined or curved position according to circumstances, but it is convenient to build it
vertical as illustrated if circumstances admit. The diaphragm D₁ D² does not extend
to the bottom of the furnace but an opening or openings d d of suitable dimensions
are provided at the base. The diaphragm flue F (or in case of more than one furnace
all such flues F F) communicates with the combustion chamber E from which is or are
led the ordinary heating flue or flues G.
At the upper extremity or inlet of each flue F a valve or damper V is fitted which
is worked from the outside of the furnace by the lever v.
I dispose the fuel more or less as illustrated in figures 2 and 7, and unburnt oxygen
and the products of the first combustion pass through the openings d d, while the
smoke and other unconsumed gases which escape from the fuel in the furnace are
conveyed (diluted with a considerable quantity of oxygen or air from the open front
of the furnace 6) through the damper V down the flue F.
These diluted gases are thus partly heated, and are distributed ready for combustion
when they meet and combine with the carbon, carbonic oxide or products of first
combustion aforesaid passing from the burning fuel of the furnace B through the
openings d at the bottom of the diaphragm D₁ D², and the whole of the gases are thus
completely consumed. By properly proportioning the dimensions of the diaphragın
flue F and by regulating the admission of air by means of the damper V according
to the quality of the fuel or other circumstances a thorough mixing of gases is
ensured, and the uneconomical result of the usual admission of too large a volume of
cold air at one place is prevented. Rapid combustion and more intense heat is thus
obtained in the combustion chamber E from which the required heat for evaporation
is communicated to and extracted by the boiler, still, crucible, or other vessel X which
is fixed in a suitable position over, in or against the flue G as indicated in the
figures.
In the arrangement of two furnaces illustrated in sheet 3 the operation and results
are precisely similar, but it is found that the special construction of hearth illustrated
may be adopted with advantage.
I
Below the end of the hearth proper B₁ I leave an open space b¹ beneath which
carry the sub-hearth B2 which is made concave or dished towards its centre in front
elevation as shown in the sectional view to the right of figure 6. The slag or other
incombustible refuse produced by the combustion will be deposited upon the

page_text: sub-hearth B2, whence it may with facility be removed and raked into the ashpit C
from the external orifice a.
By both the above described constructions the labour of stoking is greatly reduced
and the whole available quantity of heat produced in the furnace is utilized.
I am aware that the use of enclosed furnaces and combustion chambers is not new
and that the principle of adding air to the products of a first combustion has been
before applied for a like purpose, nor do 1 lay any claim to these, but having now
particularly described and ascertained the nature of this invention, and in what
manner the same is to be performed I declare that what I claim is :-
(1) The use in the construction of furnaces and closed fires of a diaphragm
containing a flue or flues placed between the furnace and its combustion chamber, as
and for the purposes described.
(2) The liereinbefore described improved construction of furnaces and closed fires
consisting in the application to or combination with such furnaces and closed fires of
a diaphragm constructed as specified and placed between the furnace and the
combustion chamber, all arranged substantially as and for the purposes set forth in
reference to the accompanying figures.
Dated this 7th day of November 1887.