Improvements in or Connected with Furnaces for Heating Steam Boilers or for other Purposes.
Year: 1888

page_text: Date of Application, 6th Nov., 1888
Complete Specification Left, 6th Aug., 1889-Accepted, 7th Sept., 1889
PROVISIONAL SPECIFICATION.
Improvements in or Connected with Furnaces for Heating Steam
Boilers or for other Purposes.
I ROBERT MARSHALL of Endrick Bank Honor Oak Park in the County of Surrey
Engineer, do hereby declare the nature of my said Invention to be as follows:-
My Invention relates to arrangements such as are for instanco described in the
Specification of my patent 4601 of 28th March 1887 the object of my present Inven-
tion being to remedy some of the defects of such an appliance and make it more
perfect in action.
In order to prevent the evolution of black smoke when the furnace is stoked or
fresh fuel added it is necessary to supply more air than is desirable when the fire burns
brightly. To provide for this I use a valve so arranged that air from between the
plate and the fire bars can be admitted over the top of the firo when green fuel has
just been added for the purpose of consuming the smoke. This valve may be in the
furnace door or in the dead plate or in casing around or parily around the door
and it may be operated by a handle extending to outside the furnace or I may fix a
hollow casing on the inside of the fire door the said casing being provided with
a valve and being inclined upwards and backwards, somewhat in the form of a
plough share so that on closing the door, a portion of the fuel is thrust forward
on the bars, clearing such portion of the fire bars or the perforated dead plate as
the hollow casing then covers so that air passes through this cleared part of the
fire bars or dead plate and the casing and therefrom over the top of the fire, the
valve being used to regulate the amount and the time of admission.
In order to properly regulate or equalize the space above and below the plate
beneath the fire bars described in the Specification of my said Patent 460187 I
provide a plate higher in the middle than at each side (say a semicircular or angled
plate with the convex side or the apex towards the underside of the fire bars.
When the grate, as often happens, consists of two or more lengths of fire bars, the
furnace being fitted with a rather deep cross bearer (or cross bearers) the plate,
when made flat, requires, in order to allow of the ashes being raked out from
beyond the cross bearer or bearers to he placed so low down that the air passage
under the plate between the plate and the bottom of the furnace, is much restricted
and will damp the draught more than is desirable. In such a case the use of the
improved form of plate above described will allow of a larger area of air passages
between the plate and the bottoin of the furnace and at the same time the ashes will
fall to the side where there is ample room to introduce the rake.
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in or Connected with Furnaces for Heating Steam
Boilers or for other Purposes.
I, ROBERT MARSHALL of Endrick Bank, Honor Oak Park, in the County of Surrey,
Engineer, 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 relates to arrangements such as are, for instance, described in the
Specification of my Patent 4601 of 28th March 1887 the object of my present Inven-
tion being to remedy some of the defects of such an appliance and make it more
nerfect in action.

page_text: Figure 1 of the accompanying drawing is a longitudinal vertical section and Figure 2
a cross section showing some of my present improvements and Figures 3 and 4 are
respectively longitudinal vertical and longitudinal horizontal sections showing another
of my improvements.
In order to prevent the evolution of black smoke when the furnace is stoked or
fresh fuel added it is necessary to supply more air than is desirable when the fire
burns brightly. To provide for this, I use a valvo so arranged that air from
between the plate B (arranged beneath the bars as in my said former Invention)
and the fire bars can be admitted over the top of the fire when green fuel has
just been added for the purpose of consuming the smoke. This valve (shewn at A)
.controls a passage a for air through the dead plate and it may be operated by a
rod and handle extending to outside the furnace as at c or I may fix a hollow
casing on the inside of the fire door as at D the said casing being provided with
a valve and being preferably inclined upwards and backwards from inside the
furnace (but downward and inwards from outside the furnace) somewhat in the
form of a plough share so that on closing the door, a portion of the fuel is thrust
forward on the bars, clearing such portion thereof as the hollow casing then
covers so that air passes through this cleared part of the fire bars and through the
casing and therefrom as required through the valve d (operated by the rod and
bandle 2) over the top of the fire, the valve being used to regulate the amount and
the time of admission. In place of the casing clearing the fuel away from a part of
the fire bars it may clear it away from a perforated dead plate.
In order to properly regulate or equalize the space above and below the plate B
beneath the fire bars described in the Specification of my said Patent 460187 I provide
a plate higher in the middle than at each side say a curved or angled plate with the
convex side or the apex towards the underside of the firebars as shewn clearly in
Figure 2. When the grate, as often happens, consists of two or more lengths of fire
bars, the furnace being fitted with a rather deep cross bearer (or cross bearers) as
shewn in Figure 1 for instance, the plate B when made flat, requires in order to allow
of the ashes being raked out from beyond the cross bearer or bearers to be placed so
low down that the area of the air passage under the plate is much restricted and will
damp the draught more than is desirable. In such a case the use of the improved
form of plate above described will overcome this objection.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the samo is to be performed I declare that what I
claim is :-
1. In furnaces a dead plate with an opening or openings therein as at a controlled
by a valve or valves operated from outside substantially as explained with regard to
the valve A.
2. The combination with the door of a furnace of a clearing device or plough sub-.
stantially as and for the purposes hereinbefore described with reference to the devico D.
3. The application to furnaces of a plate B which is curved or angled and arranged
relatively to the fire bars substantially as and for the purposes herein before described
and illustrated.
Dated this 3rd day of August 1889
J. H. JOHNSON & Co.,
Agents for the Applicant.