AN IMPROVED DOUBLE- VENTILATED SHOVEL GRATE FOR FUEL OF ANY KIND
Year: 1877

page_text: LETTERS PATENT to Henry Conradi, of 8, Lower James Street, Golden Square,
in the County of Middlesex, for the Invention of "AN IMPROVED DOUBLE-
VENTILATED SHOVEL GRATE FOR FUEL OF ANY KIND." A communication from
abroad by Nicholas Henzel, at Prag, in Austria, and Paul William Liebich, at
Tenlitz in Saxony both Engineers.
Sealed the 24th April 1878, and dated the 27th October 1877.
PROVISIONAL SPECIFICATION left by the said Henry Conradi at the Office
of the Commissioners of Patents on the 27th October 1877.
•
HENRY CONRADI, of 8, Lower James Street, Golden Square, in the County of
Middlesex. "AN IMPROVED DOUBLE-VENTILATED SHOVEL GRATE FOR FUEL OF ANY
KIND." [A communication from abroad by Nicholas Henzel, at Prag, in Austria,
and Paul William Liebich, at Teplitz, in Saxony, both Engineers.]
The present grate bar distinguishes itself from all grate bar constructions hitherto
known which are destined for the same purpose, namely, the admission of the
greatest amount of air possible by being constructed in such a manner that in spite
of the lightness of the single parts of the grate its bending or burning is rendered
quite impossible, as it occurs often with grates made of thin wrought-iron bars with
intermediate distance pieces riveted together, or with cast-iron grates, which consist
of several parallel bars cast together with connecting cross pieces.
The chosen form of a lattice great bar does not therefore appear arbitrary, but, on
the contrary, it realises the proposed end, as each grate bar consists of two parallel
longitudinal bars, with a great number of connecting cross pieces, which for their
part again work as grates. The grate bars being accordingly made large and high,
their lattice form necessarely prevents their bending and burning through the heat.
This form is therefore essential, and has not been applied yet to grate bars.
The slant cross ribs B, B, B, of the grate bars are placed at proper distances, and
are constructed as hollow curved shovels, in order to lead the enterring air in the

page_text: direction of the arrows, which is of special importance by using this grate for
locomotives.
From two to two shovels the longitudinal bars A contain openings a, a, a, which
admit the air, not only from below, but also allow the air to enter through the
space left between two grat bars. The shovels are likewise hollowed out or
pierced at b, as shown in section, E, F, so that the air can move freely in all direc-
tions, and enter into the fuel; thus the grate is doubly ventilated. It is ventilated
at a, where the air enters sidewise in the longitudinal bars, and at b, where it enters
through the cross bars formed by the shovels. In consequence of this arrangement,
the grate offers such a large cooling surface that its over-heating cannot take
place.
Acccording to these arrangements, the longitudinal, as well as the cross bars, can
be made as light as casting will permit it; and it is also possible by a clear space of
only 8/m between the bars, and a thickness of iron of only 6 millimeter (m/m) to
establish a grate which posesses 57 per cent. clear grate or cooling surface, while
an increase of the distance between the bars to 9 millimeter (m/m) will produce 60
per cent. clear grate or cooling surface, and so on. This increase of the clear grate
or cooling surface produces in most cases the important advantage that the total
surface of the grate can be considerably reduced, and a relativ greater section of air
passages is reserved than any other grate hitherto known posesses. In the meantime
the strength of the single bars, as already above stated, is not only not reduced, but, on
the contrary, increased in consequence of the considerable cooling surface it contains,
and the mixing up of massive metal upon single points being avoided.
The direct and energetic introduction of the air into the fuel guaranties in all
cases by the use of this grate a considerable economy.
Finally, a special feature of the present construction is yet to be mentioned;
namely, that the surface of the grate is plain, hollowed out, or pierced like a sieve,
without leaving projecting parts of rhomboetical shape, as it is the case in similar
constructions of massive grate bars. In the latter case grate bars of such a con-
struction do not offer a sufficient cooling surface, and the angular corners of the
projecting pyramidical shaped parts are soon melted away. This cannot take place
in the present construction of the herein-described kind of grate, as the so-formed
edges are only of two faces, so that the fire does not find proper points upon which
to exercise its destructive influence.
The novelty and peculiarity of this grate upon which the claims are based consist
therefore,―
1. In the lattice form of the grate, which prevents its bending or burning, and
offers the use of a far greater clear grate or cooling surface than it is the case in any
other grate hitherto known.
2. In the hollowing out or piercing the longitudinal, as well as the cross ribs, for
the purpose of proper ventilation.
3. In the arrangement and disposition of a part of the cross ribs, being formed
as curved shovels, in order to lead and to distribute the entering air.
4. In the construction of a plain grate surface, which does not hinder the stirring,
nor does it expose any of its parts to be destroyed through the fire.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Henry Conradi in the Great Seal Patent Office on the 26th April
• 1878.
HENRY CONRADI, of 8, Lower James Street, Golden Square, in the County of
Middlesex. "AN IMPROVED DOUBLE-VENTILATED SHOVEL GRATE FOR FUEL OF ANY
KIND. A communication from abroad by Nicholas Henzel, at Prag, in Austria,
and Paul William Liebich, at Teplitz, in Saxony, both Engineers.
"
The present grate bar distinguishes itself from all grate bar constructions hitherto
known which are destined for the same purpose, namely, the admission of the
greatest amount possible of air by being constructed in such a manner that in
spite of the lightness of the single parts of the grate its bending or burning is
rendered quite impossible, as it occurs often with grates fastened together made of
thin wrought-iron bars with intermediate distance pieces riveted together, or with
cast-iron grates, which consist of several parallel bars cast together with connecting
cross pieces, which for their part act as the above-mentionned distance pieces.
The form of a lattice grate bar, as chosen by the Inventors, in the present case
does not therefore appear to be arbitrary, but is, on the contrary, chosen in due
consideration of realising the proposed end, as each grate bar consists of two parallel
longitudinal bars, with a great number of connecting cross pieces, which for their
part again work as grates. The grate bars being accordingly made large and high or
deep, according to the appropriate conditions and the required proportions of the
heating and cooling surface, their lattice form necessarily prevents their bending or
burning through the heat. This form is therefore essential, and has not been
applied yet to grate bars.
The slanting or inclined cross ribbs B, B, B, of the grate bars are placed at proper
distances, and are constructed like hollow curved shovels or like bend plates, curved
in the most appropriate shape, so as to lead the entering air in the direction of the
arrows, which is of special importance by using this grate for locomotive engines.
The sides or walls A of the fire-grate are provided with openings a, a, a, at ap-
propriate distances, say, either from shovel plate to shovel plate or bend plate, or
between each, or from two to two plates, extending either only partly or fully as
far as its casting may allow it over its depth. The shovel or bend plates are like-
wise provided with openings b. of more or less extend, as represented in the section
E, F, allowing the air to move freely in all directions, and to enter the fuel. In
this manner the grate is doubly ventilated. It is ventilated at a, where the air
enters sidewise through the walls or sides of the bar, and at b, where it enters
through the curved shovel or bend plates forming the cross bars. In consequence of
this arrangement, the grate offers such a large cooling surface that its over-heating
cannot take place.
According to these arrangements, the walls or sides of the grate, as well as the
bend or curved shovel plates forming the cross bars, can be made as light as the
casting will permit. This arrangement or construction of the bar will also permit,
by making the openings throughout of only 8 millimeters, about 0-314 inches in
width, and by a thickness of the iron throughout of 6 millimeters, about 0.2358
inches to establish a grate, which posesses 57 per cent. clear great or cooling
surface, while an increase of the width of the openings to 9 millimeters will produce
60 per cent. of clear grate or cooling surface, and so on. This increase of the clear
grate or cooling surface produces in most cases the important advantage that the
total surface of the great can be considerably reduced, and relatively a still greater
section in the air passages is obtained than it is the case in any other grate.
the same time the strength and solidity of the single bars has not been decreased,
but, on the contrary, increased in consequence of the considerable cooling surface it
contains, and the massing of massive metal, like lumps upon single points, being
avoided.
At

page_text: The direct and energetic introduction of the air into the fuel guaranties in all
cases by the use of this grate a considerable economy.
Further, a special feature of the present construction is yet to be mentioned;
namely, that the surface of the whole grate is plain, provided with openings, spared
out like a sieve, but without leaving, as in a similar construction of massive grate
bars, projecting pieces of rhomboidal-shaped surfaces. Such grate bars do not offer
a sufficient cooling surface, and the acute angular corners of the projecting pyrami-
dical-shaped parts, each of which is formed by three planes, are soon melted away.
This cannot take place by the herein-described kind of grate, as the formed edges
are only of two faces, so that the fire does not find proper points to get hold of for its
destructive influence.
The improvements and special features of this grate upon which the claims are
principally based consists,―
1. In the lattice form of the whole grate, formed by the straight or curved ribs
of the top and the sides or walls of the grate, either formed by parallel or crossed
ribs, which prevents its bending or burning in the heat, and offers the use of a
relatively far greater clear grate or cooling surface than it is the case in any other
grate.
2. In the piercing or sparing out, or providing with openings, of the sides or
walls of the grate, as well as of the cross ribs formed by the, shovel or bend plates
for the purpose of proper ventilation.
3. In the disposition and in the arrangement of the cross ribs, of which one part
form curved shovels or bend plates for the purpose of leading and distributing the
entering air.
4. In the construction of a plain grate surface which does not hinder the
stirring nor passes single parts which are exposed to a rapid destruction by the
heat.
"
In witness whereof, I, the said Henry Conradi, have hereunto set my
hand and seal, this Twenty-fifth day of April, in the year of our Lord
One thousand eight hundred and seventy-eight.