Improvements in Fire-grates.
Year: 1890

page_text: Date of Application, 7th Oct., 1890-Accepted, 24th Jan., 1891
COMPLETE SPECIFICATION.
Improvements in Fire-grates.
1. GEORGE FREDERICK REDFERN, of the firm of G. F. Redfern & Co., The General
Patent Office, No. 4, South Street, Finsbury, in the County of Middlesex, Patent
Agents, do hereby declare the nature of this invention (a communication from abroad
by Wilnelin Lanholdt, of 1, Schellingstrasse, Berlin, in the Empire of Germany,
Architect and Engineer) and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement:―
This invention relates to a basket-grate having separate single or double bars
adapted to be moved horizontally and vertically, the said bars being inclined towards
the front of the grate whereby not only can the whole of the fuel le raked or stirred
but the separation of the ashes and cinders therefrom is facilitated as when clearing
the fire, the spaces between the bats can be widened, if required, to allow cinders of
large size to pass and therefore the jamming of cinders between the grate bars is
avoided.
In consequence of the inclination of the grate the heaviest cinders or slags
slide down to the front and the loosening of the same and admission of air to the grate
bars is thereby facilitated.
In order to enable the invention to be fully understood I will describe how it can
be carried into practice by reference to the accompanying drawing in which :—
Figures 1 and 2 are a side elevation and a transverse section respectively shewing
the improved grate bars in position and forming a single movable basket-grate:
Figures 3 and 4 are a side elevation and a plan respectively shewing another form
of the improved grate-bars:
Figures 5 to 10 are views of details.
The grate bars A are all of the form shewn in Figure 1 and are in cross section of
a T-shape, as shewn in Figure 2; the ends are provided with holes to receive
S-shaped bars for small grates, as in Figure 1, or tubes for larger grates as in
Figure 3, so as to form, when placed upon a flat frame B or iron bar, a basket with
open front and bottom.
To allow the bars to swing sideways without leaving their bearings the frame or
bars B are grooved at the places where the bars rest as shewn in Figure 2.
If it be desired to still further facilitate the swinging of the grate bars A, the ends
of the parts 6 can be fitted in balls 6, Figure 3, which balls rest in suitable concavities
in the frame B.
In order to clear the fire from ashes or slag a poker is introduced between two
grate bars which are thereby pushed aside or separated to allow the ashies or cinders
to drop through. This operation is repeated between each of the grate bars and, if a
clinker or cinder be too large to pass through the ordinary space, the opening between
the two grate bars can be widened still further by pushing them against the adjacent
grate bars which will also give way until the cinder drops through.
It will be obvious that the grate bars may be placed at any desired width
apart.
To prevent the grate bars A from becoming burned or rapidly worn out through
the intensity of heat of the combustion they can be constructed with air-passages, as
shewn in Figure 1". The grate bar A is in this case made of a pipe which is cut and
opened at the lower part, and holes d are provided at the upper part to allow air to
pass in the direction of the arrows. Instead of a pipe sheet-iron could be used.
A double grate bar with air-passages will be found still more advantageous than a
single grate bar. It consists of two grate bars a, a' combined as shewn in Figures 3,
5 and 6. The lower grate bar a is of a T-shape in cross section and fits into the
lower part of the top bar a². It is provided with longitudinal grooves e beneath its

page_text: two lateral flanges and with a longitudinal swell c with inclined sides at the top so as
to provide a secure support for the top bar a². At each side of the middle web or
flange is a number of holes cut through the longitudinal grooves.
The top grate bar a resting on the lower bar a and held by the swell c', is formed
in the shape of a saddle, narrow at the top, so as to leave between the two grate bars
a parabolic air space into which enters the air passing through the holes in the lower
grate bar a and which escapes through slots d in the sides of the upper bar a'.
In consequence of the deflection to which the air current is subjected part of it (as
shewn by the arrows in Figure 6) strikes against the inner surface of the top bar
which cools and then passes off through the slots d into the midst of the fire.
The slots d in the top bar may be made in a line with the holes c² of the lower bar
or otherwise.
To secure the top grate bar al to the lower bar a countersunk-screws C are fitted
into the top bar and screwed into the lower grate bar a. These screws become
so incrusted by the action of the fire that, when clearing the grate from ashes or
cinders and the like, an accidental separation of the two grate bars cannot occur.
In consequence of the effectual cooling of the grate bars they will not become
burned and if after long use the bars become worn out it is easy to replace the top
bar by a new one.
The grate bar is then again supported by the S-shaped tubes which fit into the
hollow part of the top bar a' instead of having special holes at the ends as in the
single grate bars shewn in Figure 1.
By using tubes for supporting the double grate bars a current of air is caused to
pass through the said tubes which are thereby prevented from becoming burnt.
By removing the S-shaped tubes Figure 3 from the double grate bars they can
be used to form a horizontal grate.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1. A fire-grate formed of separate T-shaped oscillating bars A inclined from the
back towards the front, the ends of the said bars being provided with holes, Figure 1,
or longitudinal openings, Figure 3, to receive S-shaped bars b, Figure 1, or S-shaped
tubes, Figure 3, substantially as set forth.
2. The modification in which double bars are employed each consisting of a lower
T-shaped grate bar a, Figures 6 and 9, which is provided with holes in the upper
flange, and is adapted to support a saddle-shaped grate bar a' which is made narrow
at the top and provided with holes d in its sides and which is connected to the lower
bar in such a manner as to leave an air-passage, through which the air entering
through the holes c² of the lower bar passes into the fire for the purpose of effectually
cooling each grate bar, S-shaped tubes being employed in connection with the
grate bars for the purpose of forming a basket-grate, which tubes are introduced
at the ends of the said bars, and are cooled by an air-current, substantially as set
forth.
3. The modified form of grate bars made in one piece from perforated tubes or
from suitable bent sheet-iron, substantially as herein before described.
Dated the 7th day of October 1890.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.