IMPROVEMENTS IN DOORS AND FIRE GRATES FOR FURNACES
Year: 1883

page_text: LETTERS PATENT to James Shepherd of the City of Manchester Engineer,
for an Invention of "IMPROVEMENTS IN DOORS AND FIRE GRATES FOR
FURNACES
"
PROVISIONAL SPECIFICATION left by the said James Shepherd at the Office
of the Commissioners of Patents on the 19th April 1883.
JAMES SHEPHERD of the City of Manchester Engineer. IMPROVEMENTS IN
DOORS AND FIRE GRATES FOR FURNACES.
This Invention relates to improvements in doors and fire grates for the furnaces
of steam boilers and for brewing, chemical and other purposes.
In constructing doors according to this invention the object is to obtain a larger
area opening for the admission of air to the fuel in a door of any given size, and
to obviate the liability of the parts becoming inoperative from choking up with
ashes dust &c; and to render the action of the door independent of special
attention on the part of the fireman or attendant. Also to provide an efficient
rocking bar for fire grates which may be actuated by hand or by machinery so as
to constitute a self cleaning grate
In the construction of a door the upper portion of the front thereof is cut out
excepting a narrow strip of metal up each side and across the top. On the back
of the door, grooves or recesses are formed up each side, into which the spindle of
a flat or other shaped valve or lid (which I call a regulating valve) is fitted in a
manner to allow such valve to work freely up and down. Into this same recess is
fixed at a convenient angle a plate of metal termed a deflector which extends
across the width of the door. The upper portion of this deflector is fitted with a
series of Louvre bars either fast or moveable or other equivalent arrangement. In
working; these Louvres are opposite the opening in the upper portion of the door,
and the outer surface of the Louvre grid may be covered by one or more folds of
wire gauze which promotes a more diffused spreading of the air that enters the
furnace at this point.
The deflector plate is not so deep as the door but allows a space of 4 or 5 inches
between the bottom of the deflector and the dead plate of the grate. When the
fire is in an incandescent state, the regulating valve should lie in an inclined
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page_text: position against the deflector, which closes the communication between the
atmosphere and the low level passage formed between the bottom of the deflector
and the dead plate. The opening of the regulator valve whereby it is raised from
its inclined position to a vertical one, is effected by a dead weight suspended from
suitably shaped levers that are secured to the valve and pass through an opening
in the door. When the valve is closed the actuating weight is held by a stop pin
that is screwed into the front of the furnace.
Each time the door is opened, the weight is withdrawn from the stop pin below
it thereby raising the valve and opening the low level communication between the
atmosphere and the fire. The period that the valve should be kept open, will
depend upon the quality and weight of coal laid upon the grate, the speed of the
draught, and general observation. The valve is closed by lifting the weight upon
the stop pin, when the air necessary for the later stages of combustion enters the
furnace through the Louvres only.
The fire grate is composed of cast-steel or iron bars, which are made with a
centre rib, taper or wedge shaped in cross section and of ordinary fish rail form.
Along each side of the centre rib, at regulated distances, are cast cone shaped teeth
or projections placed so as to form the spaces between them into a zig-zag course,
and to give an uniform thickness of metal through the bar at any cross section.
Along the top surface of the bar at the angle formed between the teeth from side
to side is cut or cast a Series of V or other shaped channels or grooves. These
openings connect all the air spaces together and diffuse the current over the entire
surface of the grate-A grate of any size is composed of a number of these bars
placed side by side and supported at the ends on cross bearers. Each bar is made
with a circular or semi-circular shaped end which fits into a suitable recess or step
in the bearer allowing the bar to move about with a rocking action. Motion is
communicated to the bars by means of a swing bar or rod that hangs below the
grate and is bolted or otherwise secured to the outer moveable bar on either side
thereof. Upon the upper edge of the swing bar is a series of notches or slots
corresponding in number to the bars. The bottom edge of each bar fits loosely
into one of the slots. On the bottom side of the swing bar is cast or formed an
opening to receive an eccentric disc, crank pin or other similar arrangement which
is to communicate motion from a shaft carrying the same and which runs under
the grate along one side. The shaft is supported at the ends from the cross
bearers and at the front projects a convenient distance from the boiler. The
end of the shaft is fitted with a lever or handle to be worked by hand, or the
shaft may be driven by suitable machinery continuously or intermittent.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said James Shepherd in the Great Seal Patent Office on the
19th October 1883.
JAMES SHEPHERD, of the City of Manchester, Engineer
DOORS AND FIRE GRATES FOR FURNACES."
"IMPROVEMENTS IN
This invention relates to improvements in doors and fire-grates for the furnaces
of steam boilers, and for brewing, chemical and other purposes.
In constructing doors according to this invention, the object is to obtain a larger
area opening for the admission of air to the fuel in a door of any given size, and
to obviate the liability of the parts becoming inoperative from choking up with
ashes, dust, &c; and to render the action of the door independent of special
attention on the part of the fireman or attendant. Also to provide an efficient
rocking bar for fire-grates which may be actuated by hand or by machinery, 80
as to constitute a self cleaning grate.
In the construction of a door, the upper portion of the front thereof is cut out,
except a narrow strip of metal up each side and across the top. On the back of
the door, or it may be the front thereof, grooves or recesses or hinges are formed at
each side, into which the spindle of a flat, or other shaped valve or lid (which I
call a regulating valve) is fitted in a manner to allow such valve to work freely up
and down or to and fro.
Into this same recess is. fixed at a convenient angle a plate of metal termed a
deflector, which extends across the width of the door. The whole, or a portion of
this deflector is fitted with a series of Louvre bars either fast or moveable, or other
equivalent arrangement.
In working, these Louvres are opposite the opening in the upper portion of the
door, and the outer surface of the Louvre grid may, if desired, be covered by one
or more folds of wire gauze which promotes a more diffused spreading of the air
that enters the furnace at this point.
The deflector plate is not so deep as the door, but allows a space of 4 or 5 inches
between the bottom of the deflector and the dead plate of the grate. When the
fire is in an incandescent state, the regulating valve should lie in an inclined
position against the deflector, when fitted internally, or against the door frame
when fitted externally, thereby closing the communication between the atmosphere
and the low level passage formed between the bottom of the deflector and the
dead plate. The opening of the regulator valve whereby it is raised from its
inclined position to a somewhat vertical one, or vice versa, is effected by a dead
weight suspended from suitably shaped levers that are.secured to or actuate the
valve, and pass through an opening in the door. When the valve is closed, the
actuating weight is held by a stop pin that is screwed into the front of the
furnace.
Each time the door is opened, the weight is withdrawn from the stop pin below
it, thereby raising the valve, and opening the communication between the
atmosphere and the fire.
By lifting the weight again upon the stop pin, the valve is closed, the process
being repeated as required. The period that the valve should be kept open, will
depend upon the quality and weight of ooal laid upon the grate, the speed of the
draught, and general observation.
The fire-grate is composed of cast steel or iron bars, which are made with a
centre rib, taper or wedge shaped in cross section, and of ordinary fish rail form.

page_text: Figs 1 and 2 shew elevations of portions or my apparatus, and figs
shew sections of portions thereof.
Ա
Fig 5 shews a plan of other portions, and Fig 6 shews a transverse section
at A. B, and Fig 7 a similar section in another position of the rocking bars.
Fig 8 is a longitudinal view partly in section, partly in elevation.
The same letters indicate corresponding parts wherever they occur.
a. a is the furnace door framing, b. b, is the regulating valve swinging on
suitable hinges, and capable of closing the orifice in the door, either as an internal
or external valve, as shewn in Figs 1, 2, 3, and 4. c. c, is the deflector fitted with
Louvre bars c. c², which may be made moveable if desirable, and may have a
covering of wire gauze, to promote a more diffused spreading of the air. d. d is
the dead weight resting on the stop pin e. e. When the door is opened, the
weight d. d is drawn forward from the stop pin, and by gravity takes the position
shewn by the dotted lines, and thus by means of the lever attachments, opens the
regulating valve b. b. to a position in like manner indicated. In case of the
external form of valve being used, a corresponding modification of parts is
necessarily adopted as shewn.
f. fare fire-bars, a portion of which are shewn in position in plan forming a
zig zag arrangement of air courses, and have grooves or further air courses cut or
cast on their upper surfaces.
Motion is communicated to these firebars by means of the swing bar g. g
attached to the outer bar on each side, and actuated by the arms h. h.
connected thereto by pin joint, such arms being firmly attached to the shaft i. i,
having at the outer end the handle h¹. h¹, which can be operated at will by the
attendant.
Having now described my improvements, and means I adopt in carrying the
same into effect, I would have it understood that I do not confine myself to the

page_text: precise details shewn and described, as variations may be made, without departing
from the peculiar character of the invention.
But what I do claim is
First. The arrangement of furnace doors with regulator valves operated
automatically by means of dead weight mechanism when such doors are opened,
in manner substantially as shewn and described.
Second. The peculiar construction and arrangement of fire bars, forming zig zag
air passages between them, and grooved air courses on their upper surfaces, and
also capable of a rocking motion; in manner substantially as shewn and
described.
Third. The combination of the various parts of apparatus forming fire-doors
and grates for furnaces, in manner substantially as shewn and described.
In witness whereof, I, the said James Shepherd have hereunto set my
hand and seal, this Seventeenth day of October, in the year of our Lord,
One thousand, eight hundred, and eighty-three.
Witness
GEORGE FREDERICK GADD
Assistant Consulting Engineer
64 Barton Arcade
Manchester
JAMES SHEPHERD (L.S.)