Improvements in or connected with Step Grate Furnaces.
Year: 1892

page_text: Date of Application, 18th July, 1892
Complete Specification Left. 18th Apr., 1893-Accepted, 20th May, 1893
PROVISIONAL SPECIFICATION.
Improvements in or connected with Step Grate Furnaces.
I, GEORGE FLETCHER, of Masson Works, Litchurch, Derby, in the County of
Derby, Engineer, do hereby declare the nature of this invention (a communication
to me by George Brocklehurst, of the Island of Barbados, West Indies,
Engineer) to be as follows:-
This invention relates to furnaces the fire bars of which are on the step grate
principle and either fixed or adapted to rock.
The object of the said invention is to cause a more complete combustion of fuel
especially such as megass and straw and similar substances by admitting a large
quantity of air through the same without leaving a large space through which the
fuel can fall, and to provide means whereby the furnace can be readily cleaned and
have clinkers and other solid products of combustion readily removed.
According to this invention the bars are made somewhat like an ordinary fire
bar but having a series of steps cast on them, the bars lying side by side and the air
entering between the steps; or the bars are constructed of ordinary flat plates with
air spaces cast in them and arranged to lie across the furnace, one plate being above
the other as in steps.
When bars having steps cast on them are used I arrange at the lower ends
thereof a plate extending across the bottom of the furnace and adapted to oscillate,
and in connection with the bars is an arrangement of levers by means of which a
rocking motion is given to them to break up the clinker or ash. By causing the
plate hereinbefore referred to to oscillate the ash which collects at the bottom of
the furnace can be precipitated into a pit beneath. The furnace is fed from a
hopper through the roof of the same.
When the grate is of greater length than one bar I advantageously place the
lever arrangement in conjunction with the adjacent ends of the two lengths but in
the case of single bars the lever arrangement is preferably placed at the lower end
thereof.
In the case of a grate composed of flat plates extending across the furnace with
the air space beneath, each bar is preferably connected to a lever, the several
levers being connected to a rod which can be moved by turning a handle, wheel or
otherwise to cause the plates or steps to oscillate on their centres, and so break up
the clinker.
T
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1003
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in or connected with Step Grate Furnaces.
I, GEORGE FLETCHER, of Masson Works, Litchurch, Derby, in the County of
Derby, Engineer, do hereby declare the nature of this invention (a communication
to me by George Brocklehurst, of the Island of Barbados, West Indies,
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 furnaces the fire bars of which are on the step grate
principle and either fixed or adapted to rock.
The object of the said invention is to cause a more complete combustion of fuel
077

page_text: especially such as megass and straw and similar substances by admitting a large
quantity of air through the same without leaving a large space through which the
fuel can fall, and to provide means whereby the furnace can be readily cleaned and
have clinkers and other solid products of combustion readily removed.
According to this invention the bars are made somewhat like an ordinary fire
bar but having a series of steps cast on them, the bars lying side by side and the
air entering between the steps; or the bars are constructed of ordinary flat plates
with air spaces cast in them and arranged to lic across the furnace, one plate being
above the other as in steps.
To enable the invention to be fully understood I will describe how it can be
carried into practice by reference to the accompanying drawings in which :-
Figure 1 is a sectional elevation of a step grate furnace constructed according to
this invention the fire bars having the steps cast thereon and being each formed in
two parts or lengths adapted to oscillate.
Figure 2 is a section of the furnace at right angles to Figure 1 and showing the
bars in front elevation.
Figure 3 is a side elevation of a similar bar but made in a single piece or
length.
Figure 4 is a front elevation showing the bars in position.
Figure 5 is a side elevation showing the bars constructed of flat plates extending
across the furnace.
Figure 6 is a front elevation of Figure 5.
Similar letters in the figures indicate similar or corresponding parts.
In Figures and 2 a a are the fire bars each constructed of two parts or lengths
as shown, the outer ends of which are adapted to oscillate in brackets or
bearings c c d d are the steps cast on the bars a which when in position lie side by
side as shown in Figure 2; ee are the air spaces between the steps d'is a plate
extending across the bottom of the furnace at the lower end thereof and adapted to
oscillate by means of a handle a¹ and g g is an arrangement of levers attached to
each alternate bar and to a bar and adapted to be operated by a lever handle i
whereby a rocking motion can be given to the bars à a and the clinker or ash
broken up. By causing the flat plate to oscillate the ash which collects at the
bottom of the furnace can be precipitated to the pit beneath. The furnace is fed
from a hopper through the roof of the same at j.
When the grate is made up of single bars a as shown in Figures 3 and 4, I
advantageously rest the upper end 6 of the bars in a bracket or bearing c and the
lever arrangement gg is preferably placed at the lower end thereof.
C
In the case of the grate shown in Figures 5 and 6 composed of flat plates d
extending across the furnace with the air space beneath and placed one above the
other as in steps, each bar is cast or otherwise fixed on a pivot bar b, and is prefer-
ably connected to a lever g the several levers being connected to rods g¹ which can
be moved by turning a hand-wheel or otherwise to cause the plates or steps d to
oscillate on their centres, and so break up the clinker.
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 step grate furnace having bars with steps cast upon them and arranged
substantially as hereinbefore described and illustrated in Figures 1. 2. 3. and 4 of
the accompanying drawings.
2. A step grate furnace having flat plates or bars fixed across the furnace one
above the other as in steps, substantially as described.
3. In a step grate furnace the arrangement of levers for causing the bars to rock,
substantially as hereinbefore described and illustrated in Figures 1. 2. 3. and 4 of
the accompanying drawings.
4. In a step grate furnace the arrangement of mechanism for causing the flat
plates or steps to oscillate and so break up the clinkers substantially as

page_text: hereinbefore described and illustrated in Figures 5 and 6 of the accompanying
drawings.
5. The manufacture and use of bars for step grate furnaces constructed as herein.
described whether arranged to be fixed or to oscillate substantially as set forth and
as illustrated in the accompanying drawings.
Dated the 18th day of Annil 1802
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.