A Slow-combustion Ventilating Grate or Fireplace.
Year: 1889

page_text: Date of Application, 10th Dec., 1889
Complete. Specification Left, 22nd Aug, 1890-Accepted, 1st Nov., 1890
PROVISIONAL SPECIFICATION.
A Slow-combustion Ventilating Grate or Fireplace.
GEORGE TINDALL PLUNKETT Lieutenant-Colonel, Royal Engineers Fort House,
Gravesend do hereby declare the nature of this invention to be as follows:-
An improved form of grate which economizes fuel with a specially formed coving
or hood of cast iron or other material to ensure the proper formation of the lower part
of the flue by which a good draught is obtained and smoky chimney prevented as
shown in accompanying three sheets of drawings. When a current of warm air is
required a chamber of improved form is made behind the fireplace and the coving is
made in one piece with the back of the fireplace as shown in the drawings, Figs. 2, 3,
4 & 5; when the air current is not required the coving is made separately as shown
in Figs. 8, 9 and in this case a template, Fig. 10, is provided to ensure the proper
curving of the back of the fireplace and proper position of coving with respect to the
grate.
The fireplace is made in different sizes but the proportions of the parts, the form of
the coving and throat and their relative positions are maintained.
*Dated this 7th day of December 1889
GEORGE TINDALL PLUNKETT.
COMPLETE SPECIFICATION.
A Slow-combustion Ventilating Grate or Fireplace.
I, GEORGE TINDALL PLUNKETT of Fort House, Gravesend in the County of Kent
Lieutenant-Colonel in the Royal Engineers 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 :-
My invention has firstly for its object to arrange the form of flues to fire places by
means of a specially made coving of cast iron, stoneware or other suitable material, so
as to ensure the proper throating of the chimney and the proper curvature and
dimensions of the lower parts adjoining the grate, by means of which a good draught
is obtained and smokiness prevented. Secondly in cases where a current of warm air
is desired to construct the back of the grate so that a warm air chamber is formed, the
air from outside of buildings being admitted through a grating in the wall and led in.
a zig-zag direction around specially, provided heating plates and around the coving
and ultimately by means of a separate air channel over the grate, through a louvred
grating in the chimney breast into the room. Thirdly in conjunction with the above.
two improvements, the slow combustion grate is made of improved form, so as to
economize fuel. For these purposes I construct a fire grate as I will proceed to
describe with reference to the drawings accompanying my Provisional Specification
Sheets Nos. 1, 2 and 3, in which with regard to Sheet No. 1, Fig. 1 shews a front
elevation of my improved slow combustion fire grate with the ventilating or hot air-
arrangement applied thereto; Fig. 2 shews a sectional plan of same; Sheet No. 2.
Fig. 3, a vertical section at right angles to face; Fig. 4, a sectional plan on line A. B
(Fig. 3), about three feet from ground line and Fig. 5 a back elevation of grate
shewing arrangement of warm air chamber. Sheet No. 3 shews a variation in design
when a warm air ventilating chamber is not required. In this case Fig. 6 shews a
front elevation of a fire place embodying my improvements, Fig. 7 a sectional plan of
same, Fig. 8 a vertical section of fire place at right angles to face, Fig. 9 a top plan
of coving and Fig. 10 a template to give true form of lower part of grate which would
be formed of fire bricks in this case. The face design may be of any known pattern,
J

page_text: but by preference I employ that shewn on Sheet No. 1. for a ventilating grate, and
that shewn on Sheet No. 3 for a non-ventilating grate.
The special feature in both forms of grate shewn on Sheets Nos. 1, 2 and 3 is the
cast iron or stoneware coving shewn at C, which is so shaped and situated with respect
to the fireplace, as to assist the draught and to prevent smokiness. In the case
of Sheets Nos. 1 and 2 the coving is cast as part of the grate, the whole being in one
piece and including the back heating plates D. In the case of Sheet No. 3 the coving
of cast iron or other material is in a separate piece as indicated in Fig. 8, but its
relative position to the grate is the same as in Sheet No. 1.
In Sheets Nos. 1 and 2 circulating air spaces are made at E Figs. 2, 3 and 5 and
space F Fig. 5 shews the point at which warm air leaves the grate proper and travels
towards louvre in chimney breast and then into room. This hot air chamber is better
adapted for giving a good current of hot air, than the patterns hitherto used inasmuch
as the air is forced to circulate round the coving & upper part of the grate. The
form of firebrick lining to grate (which is of an improved slow combustion pattern)
as shewn in Figs. 1, 2 and 3 Sheets Nos. 1 & 2 and Figs. 6, 7 and 8, Sheet No. 3 is
so designed as to economize fuel, inasmuch as the depth of the grate from bars to
back is such as to obtain the largest possible proportion of heat from the fuel burned,
the jambs are sloped at such an angle that all the heat radiated against them is
reflected into the room and the back is shaped to a curve which causes the ascending
current of smoke to impinge upon it by which means much of the smoke is consumed
by the heated surface of fire brick and great heat is radiated from this surface into the
room, whilst the projection is not curved too suddenly so as to throw the ascending
current forward, but allows it to pass upwards to the throat of the chimney. The
template shewn in Fig. 10 Sheet No. 3 ensures that the back of the grate shall be
built of the proper form in cases where the non-ventilating pattern is adopted.
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In these cases the bars, fire lumps and coving are supplied by the manufacturer and
by placing the lower edge of the template on the bottom of the fire place, with the
point in Fig. 10 Sheet No. 3 corresponding with the point X "in Fig. 8
Sheet No. 3 and the edge "d" of the template vertical, the back profile "a b c
the curve to which the bricklayer must shape the lining and the point C is the
point of junction with the coving, thus the form of the back and the position of the
coving are ensured.
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The above mentioned forms of grates are made in different sizes, but the pro-
portions of the parts, the form of the coving and throat and their relative positions
are maintained.
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 I
claim is :-
1. Constructing fire places with covings of cast iron, stoneware or other material
of the shape and relative dimensions shewn at C and in the position indicated on
drawings.
2. The adaptation of this coving to a slow combustion grate of improved form
as also shewn in the drawings.
3. The adaptation when required of a warm air chamber to this form of slow
combustion grate and the construction of this chamber, so that the air becomes
more thoroughly heated.
GEORGE TINDALL PLUNKETT.