IMPROVEMENTS IN GRATES AND FIRE-PLACES, OR APPARATUS FOR THE GENERATION OF HEAD
Year: 1852

page_text: LETTERS PATENT to John Finlay, of Glasgow, in the County
of Lanark, North Britain, Ironmonger, for the Invention of
"IMPROVEMENTS IN GRATES AND FIRE-PLACES, OR APPARATUS FOR THE
GENERATION OF HEAD"
Sealed the 16th March 1853, and dated the 1st October 1852.
PROVISIONAL SPECIFICATION left by the said John Finlay at the
Office of the Commissioners of Patents, with his Petition, on the
1st October 1852.
I, JOHN FINLAY, of Glasgow, in the County of Lanark, North
Britain, Ironmonger, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN GRATES AND FIRE-PLACES, OR APPARATUS FOR THE
GENERATION OF HEAT," to be as follows; that is to say:
This Invention relates to various improvements in fire grates, for
obtaining increased efficiency of draught therein, together with the
better radiation of heat, and the accurate and easy adjustment of the
regulating details for modifying the draught, and the combustion of the
fuel and the consumption of smoke. According to one modification of
fire grate (suitable for dwelling houses) wherein this Invention is applied
or put in practice, a single overhanging draught door is formed at the
back of the grate, and hinged by its bottom or lower edge. This door

page_text: is so contrived that when fully open, to allow of the greatest possible
extent of air passage to the chimney, it leans or inclines backwards
from its bottom joint towards the chimney, or the wall in which the
grate is placed; and when the door is fully closed to shut off all
chimney draught its upper edge inclines forward from its bottom joint
towards the room. This door regulates the main or what may be termed
the front direct draught into the flue or chimney; the smoke and
heated air passing off from the fire-place by the upper portion of the
door. But the door is adapted as well for furnishing a means of back
draught or secondary air passage at a lower level, by which means any
thick green smoke is at once conveyed off from the level of the surface
of the coals in the grate to the flue by a short route, so as to keep the
fuel clear of smoke, to aid the, draught, and to prevent the chance of
such thick heavy smoke getting into the apartment to be heated.
This back draught is obtained by hanging the lower edge of the door
to the fixed portion of the back of the grate at or near the level of the
surface of the burning fuel, by means of a horizontal joint or centre pin,
beyond which joint pin the lower edge of the door is slightly prolonged,
so as to form a secondary regulating door or valve. The door thus
becomes a double lever; the upper side or main portion being arranged
to close by moving forward, whilst the lower edge beneath the joint
similarly closes its narrower duct or passage by the consequent back-
ward motion. Suitable means being provided for the escape of the
dense smoke through the lower opening into the flue, whatever smoke
so passes escapes up the chimney behind the main portion of the door,
and any heated gases or air so passing thus produce radiant heat by
acting on the door from behind. This duplex arrangement of door
thus opens and closes both passages simultaneously, and any regulation
of the main door correspondingly adjusts that for the lower back draught,
and a means is afforded by it of taking off the sluggish smoke at once
from a green or fresh fire, so as to give the smoke no chance of
escaping into the room. The adjustment of the draught door may be
effected in various ways, as, for example, by a notched catch rod hinged
to the door, and contrived to be available from the front of the door or
side of the grate, the notches or detents working over a fixed stop

page_text: behind the grate. Or, instead of this arrangement, the adjusting rod or
lever may be formed with an undulating edge, or with rounded notches,
so that a weight hung on the end of the lever, or a spring, either in the
lever itself or detached, may hold the door at any determined undula-
tion. By this plan mere pressure on the door will adjust it either way,
without attending to the lever or catch rod. Or, instead of this plan, the
door may be set on a friction joint centre, adjustable to give any required
degree of frictional hold to retain the door at any angle at which it may
be set. Frictional side pressure by a spring may also be used for the
same end, so as to give a noiseless plan of adjustment, with simple and
easily manageable details.
SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said John Finlay, in the Great Seal Patent Office, on
the 1st April 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
JOHN FINLAY, of Glasgow, in the County of Lanark, North Britain,
Ironmonger, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of October in the year of our
Lord One thousand eight hundred and fifty-two, in the sixteenth year
or Her reign, did for Herself, Her heirs and successors, give and grant
unto me, the said John Finlay, Her special licence that I, the said
Jolin Finlay, my executors, administrators, and assigns, or such others
as I, the said John Finlay, my executors, administrators, or assigns,
should at any time agree with, and no others, from time to time and at
all times thereafter during the term therein expressed, should and lawfully
might make, use, exercise, and vend, within the United Kingdom of
Great Britain and Ireland, the Channel Islands, and Isle of Man, an
Invention for "IMPROVEMENTS IN GRATES AND FIRE-PLACES, OR APPARATUS
FOR THE GENERATION OF HEAT," upon the condition (amongst others) that
I, the said John Finlay, by an instrument in writing under my hand
and seal, should particularly describe and ascertain the nature of the

page_text: said Invention, and in what manner the same was to be performed,
and cause the same to be filed in the Great Seal Patent Office within
six calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said John Finlay, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement, reference being had to the drawing hereunto
attached, and to the letters and figures marked thereon, (that is to say):
My said Invention relates to various improvements in fire grates, for
obtaining increased efficiency of draught therein, together with the
better radiation of heat, and the accurate and easy adjustment of the
regulating details for modifying the draught, and the combustion of the
fuel, and the consumption of smoke. According to one modification of fire
grate (suitable for dwelling houses) wherein this Invention is applied or
put in practice, a single overhanging draught door is formed at the
back of the grate, and hinged by its bottom or near its lower edge.
This door is so contrived that, when fully open, to allow of the greatest
possible extent of air passage to the chimney, it leans or inclines back-
wards from its bottom joint towards the chimney, or the wall in which
the grate is placed; and when the door is fully closed, to shut off all
chimney draught, its upper edge inclines forward from its bottom joint
towards the room. This door regulates the main or what may be termed
the front direct draught into the flue or chimney; the smoke and heated
air passing off from the fire-place by the upper portion of the door.
But the door is adapted as well for furnishing a means of back draught
thick
or secondary air passage at a lower level, by which means any green
smoke is at once conveyed off from the level of the surface of the coal
in the grate to the flue by a short route, so as to keep the fuel clear of
smoke, to aid the draught, and to prevent the chance of such thick
heavy smoke getting into the apartment to be heated. This back
draught is obtained by hinging the lower edge of the door to the fixed
portion of the back of the grate, at or near the level of the surface of
the burning fuel, by means of a horizontal joint or centre pin,

page_text: beyond which joint pin the lower edge of the door is slightly
prolonged, so as to form a secondary regulating door or valve,
The door thus becomes a double lever, the upper side or main portion
being arranged to close by moving forward, whilst the lower edge
beneath the joint similarly closes its narrower duct or passage by the
consequent backward motion. Suitable means being provided for the
escape of the dense smoke through the lower opening into the flue,
whatever smoke so passes escapes up the chimney behind the main
portion of the door, and any heated gases or air so passing thus produce
radiant heat, by acting on the door from behind. This duplex arrange-
ment of door thus opens and closes both passages simultaneously, and any
regulation of the main door correspondingly adjusts that for the lower
back draught, and a means is afforded by it of taking off the sluggish
smoke at once from a green or fresh fire, so as to give the smoke no
chance of escaping into the room. The adjustment of the draught door
may be effected in various ways, as, for example, by a notched catch rod
hinged to the door, and contrived to be available from the front of the
door or side of the grate, the notches or detents working over a fixed
stop behind the grate. Or, instead of this arrangement, the adjusting rod
or lever may be formed with an undulating edge, or with rounded
notches, so that a weight hung on the end of the lever, or a spring, either
in the lever itself or detached, may hold the door at any détermined
undulation. By this plan, mere pressure on the door will adjust it
either way, without attending to the lever or catch rod. Or, instead of
this plan, the door may be set on a friction joint centre, adjustable
to give any required degree of frictional hold, to retain the door
at any angle at which it may be set. Frictional side pressure by
a spring may also be used for the same end, so as to give a noiseless
plan of adjustment, with simple and easily manageable details.
my
Figure 1, on my sheet of drawings, represents a front elevation of a
domestic fire-grate, as arranged according to one modification of
im-
provements; Figure 2, is a transverse vertical section, corresponding to
Figure 1, showing the direction of the draught current; Figure 3, is a
horizontal section of the grate, showing the bars complete in plan;

page_text: and Figure 4, is a detail of the hinge of the draught door. The over-
hanging door A, is, in this case, hinged at B, by a pair of side pivots,
which rest in recesses in a hinge support C, one on each side of the
grate; D, being the prolongation of the door below the joint or centre of
suspension. To form the back draught, as arranged in Figure 2, the
draught door is full open, and the main-draught current passes off in the
direction of the arrow E, in front of the door, to the chimney; whilst
the back-draught or secondary current passes through the smaller
aperture F, and escapes to the chimney also, along the space G, between
the back of the draught door and the front of the stationary inclined
back plate H. To the upper edge of this back plate is fastened a
hinge-piece I, to which is loosely jointed the rod or link J, formed
with undulatory notches on its lower edge. This link, which acts as the
detent for the door, projects forward, and rests upon the upper edge of
the door; so that when the latter is drawn forward by the ornamental
projection K, to the position, for example, indicated by the dotted lines
L, its loose end bears upon the door, and retains it at the desired angle.
In this way the domestic may easily adjust the door to any extent of
opening, as a slight pressure in either direction will cause the upper
edge of the door to slip along the detent undulations to the intended
position. The dotted door E, also illustrates the mode in which any
change in its position correspondingly affects the back or secondary
draught aperture.
Having now described and particularly ascertained the nature of my
Invention, and the manner in which the same is or may be used or
carried into effect, I may observe, in conclusion, that I do not confine
or restrict myself to the precise details or arrangements which I have
had occasion to describe or refer to, as many variations may be made
therefrom without deviating from the principles or main features of my
Invention; but what I consider to be novel and original, and therefore
claim as the Invention secured to me by the herein-before in part recited
Letters Patents, is-
First, the application and use of an overhanging back door, for
obtaining two separate vents or passages for the products of combustion.

page_text: Second, the system or mode of arranging and constructing fire-grates
and fire-places, wherein the front or main draught, and the back or
secondary draught, are simultaneously adjusted and regulated.
Third, the system or mode of carrying off the dense smoke and
vapours of fuel by a back or secondary draught, as herein-before
described.
Fourth, the application and use of a detent link or holder, with
undulating notches or holding surfaces, acting in both directions by the
use of lateral or simple pressure only, as herein-before described.
In witness whereof, I, the said John Finlay, have hereunto set my
hand and seal, this Twenty-fifth day of March One thousand
eight hundred and fifty-three.
JOHN FINLAY. (L.F.)