Improvements in and connected with Furnace Grates adapted for Natural or Forced Draught.
Year: 1899

page_text: Date of Application, 14th July, 1899
Complete Specification Left, 17th Apr, 1900-Accepted, 26th May, 1900
Improvements in and connected with Furnace Grates adapted for
Natural or Forced Draught.
I, JOHN SILLARS BINNIE, of Belmont, Kilmalcolm, Renfrewshire, Engineer, do
hereby declare the nature of this invention to be as follows:-
This invention relates to the furnace grates of steam boilers and it has for its
object to improve the arrangement and construction of the same.
The new grate consists of a number of bars arranged transversely across the furnace
being held in place by means of suitable cast iron bearers which extend along the
sides of the furnace from the front to the bridge. Every alternate fire bar is hollow
and of a tubular shape and is held revolubly in place in the cast iron bearers afore-
said. The other or intermediate fire bars are solid and are fixed in position. They
are made in section somewhat of a T shape with a broad upper surface which tapers
away underneath at each side.
The hollow fire bars are made with air holes or slots through which the air can
pass freely from the ashpit to the fire. One end of each hollow fire bar is made
simply as a short journal and the other end is made with a journal and worm wheel.
The bearer which carries the plain ends of the hollow fire bars is simply a cast iron
box or tube having its back or bridge end closed and provided with a hollow extension
by means of which an air connection can be established between the bearer and an
air chamber at the top of the fire bridge. This extension fits into a hole at the top
of the fire bridge and thereby serves to retain the bearer in position. The front end
of the bearer is open and is provided with two lugs whereby it can be bolted to the
front plate of the furnace. A hole in the front plate is made to correspond with the
hole in the bearer end so that there is a free air passage from the front of the boiler,
through the bearer, to the air chamber of the fire bridge.
The bearer for the wheel ends of the hollow fire bars is made in halves and is fixed
into the bridge and to the front plate of the boiler in the same manner as the other
bearer. A worm shaft having a series of sinall worms or screws on it extends along
the inside of the lower half of this second bearer. The worins are arranged to gear
with the worm wheels of the hollow fire bars so that when the worm shaft is rotated
all the hollow fire bars have a continuous rotatory motion imparted to them.
the top half of the second bearer is removed any one of the wheel ends of the hollow
fire bars can be lifted up and the hollow fire bar then taken out of place by merely
pulling its wheel end to the side of the furnace until its other journal is clear of the
first bearer.
When
The hollow fire bars are arranged at short and equal distances apart and the spaces
between them are partially filled by the fixed bars aforesaid. The ends of these fixed
bars fit into slots in the side bearers and their weight is carried by projecting ledges

page_text: on the bearers. The upper surfaces of the fixed bars are preferably arranged a little
below the top of the hollow fire bars.
Steam jets are or may be arranged to blow into the holes or openings of the side
bearers. These steam jets cause a strong current of air and steam to pass through
the bearers and as the holes or bearings therein for the journals of the hollow fire
bars are considerably larger than the journals themselves it follows that the air and
steam blast will pass through the openings left at the top halves of the bearings and
strike on the ends of the hollow fire bars and pass upwards through the fire.
A small air outlet is or may be provided in the chamber of the fire bridge and be
arranged to communicate with either the ashpit or the flue at the back of the
bridge.
When the steam jets are not turned on air will pass through the bearers by
natural draught. The steam jets are however provided in order to insure a good
draught of air for the purpose of keeping the side bearers and all the working parts
from overheating and the bearings clear of dust and small clinkers.
The worms are, by preference, made with projections at one end and recesses at
the other so that they interlock. They may be threaded on a light spindle or shaft
which front end projects through the furnace front and is driven by suitable gear.
The fuel can be fed to the furnace by means of a mechanical stoker with a ram
feed, or by hand, or by a combination of both. The fuel may however be fed by
gravitation from a running hopper.
The arrangement can be readily adapted for forced draught by closing the ashpit
at the front by an airtight door and by opening communication between the side
bearers and the ashpit either by making holes in the bottoms of the bearers or by
making the hollow fire bars with open ends. Additional air can be supplied by
means of additional steam induced blasts.
The openings in the hollow fire bars are, by preference, lessened in number and
(or) size from the front of the furnace grate to the back. The first two or three of
the fixed bars may have holes made in them.
H. D. FITZPATRICK,
100, Wellington Street, Glasgow, Agent.
Improvements in and connected with Furnace Grates adapted for
Natural or Forced Draught.
I, JOHN SILLARS BINNIE, of Belmont, Kilmalcolm, Renfrewshire, 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:—
This invention relates to the furnace grates of steam boilers and it has for its
object to improve the arrangement and construction of the same.
In order that my said invention may be properly understood I have hereunto
appended two explanatory sheets of drawings which show, by way of example, an
ordinary "Lancashire" boiler fitted with my improved grate.
Fig. 1 is a front elevation of the boiler showing the gear for the grate.
Fig. 2 is a side elevation of the same.
Fig. 3 is a longitudinal section of the furnace of the boiler.
Fig. 4 is a cross section on the line X-X Fig. 3.
Fig. 5 is a front view, Fig. 6 an end view and Fig. 7 a plan view of a fire bar,

page_text: Fig. 8 is a section and Fig. 9 a front view of one of the bearers.
Fig. 10 is a plan view of the worm shaft.
Referring to the drawings whereon the same reference numerals wherever repeated
indicate the same parts.
The new grate consists of a number of bars 1, 2, arranged transversely across the
furnace being held in place by means of suitable cast iron bearers 3, 4, which extend
along the sides of the furnace from the front to the bridge 5. Every alternate fire
bar 2 is hollow and of a tubular shape and is held revolubly in place in the cast iron
bearers aforesaid. The other or intermediate fire bars 1 are solid and are fixed in
position. They are made, in section, somewhat of a T shape with a broad upper
surface which tapers away underneath at each side. The shape of the fire bars 1 is
clearly shown at Figs. 5, 6 and 7. As will be seen each bar 1 has a projection 6 at
each end and these projections fit into recesses 7 made in the side bearers 3, 4.
8 are ledges cast on the bearers for the purpose of supporting the ends of the
bars 1.
The hollow fire bars 2 are made with air holes or slots 9 through which air can
pass freely from the ashpit 10 to the fire. One end of each hollow fire bar is raade
simply as a short journal 11 and the other end is made with a journal 12 and worm
wheel 13: The bearer 3 which carries the plain ends of the hollow fire bars is simply
a cast iron box or tube having its back or bridge end closed and provided with a
hollow downward extension 14 by means of which an air connection can be established
between the bearer and an air chamber 15 at the top of the fire bridge. This
extension fits into a hole at the top of the fire bridge and thereby serves to retain the
bearer in position. The front end of the bearer is open and is provided with two
lugs 16, 17, whereby it can be bolted to the front plate of the furnace. A hole 18
(Fig. 1) in the front plate is made to correspond with the hole in the bearer end so
that there is a free air passage from the front of the boiler, through the bearer, to the
air chamber 15 of the fire bridge.
The bearer for the wheel ends of the hollow fire bars which is shown at
Figs. 8 and 9 is made in halves 4", 4, and is fixed into the bridge and to the front
plate of the boiler in the same manner as the other bearer. 14 is the hollow
extension for fitting in the bridge and 16, 17, the lugs for securing the bearer to the
front plate of the furnace. 19 are holes or bearings for the journals of the fire bars 2.
Holes 18 are also made in the front plate of the furnace to correspond with the
passage in each bearer 4.
A worm shaft 20 having a series of small worms or
screws 21 on it extends along the inside of the lower half of this second bearer (see
Fig. 4). The worms are arranged to gear with the worm wheels of the hollow fire
bars so that when the worm shaft 20 is rotated all the hollow fire bars will have a
continuous rotatory motion in one direction imparted to them so as to constantly and
gradually feed the fuel forward towards the bridge. When the top half 4 of the
bearer 4 is removed any one of the wheel ends of the hollow fire bars can be lifted up
and the hollow fire bar then taken out of place by merely pulling its wheel end to
the side of the furnace until its other journal is clear of the bearer 3.
The hollow fire bars are arranged at short and equal distances apart and the spaces
between them are partially filled by the fixed bars aforesaid. The upper surfaces of
the fixed bars are preferably arranged a little below the level of the tops of the hollow
fire bars.
The worm shafts 20 can be rotated in any well known manner but I prefer to
rotate them by means of the gear shown at Figs. 1 and 2. Each worm shaft 20 has
a worm wheel 22 at its outer end and these worm wheels gear with a worm 23 at the
lower end of a vertical shaft 24 which latter may be the shaft for driving the
nechanical stoker if such a stoker is used. 25, 26, are bearings for the shaft 24. The
shaft 24 drives the mechanical stoker shaft 27 by means of the worin gear 28, 29.
The shaft 24 can be driven from an overhead shaft rotated by the engine.
Steam jets may be arranged to blow through nozzles 30, connected by pipes 31
with the steam space of the boiler, into the holes or openings 18 leading to the side
bearers. These steam jets cause a strong current of air and steam to pass through

page_text: the hollow bearers and as the holes or bearings therein for the journals of the hollow
fire bars are considerably larger than the journals themselves it follows that the air
and steam blast will pass through the openings left at the top halves of the bearings
and strike on the ends of the hollow fire bars and pass upwards through the
fire.
A small air outlet is or may be provided in the chamber 15 of the fire bridge
and be arranged to communicate with either the ashpit or the flue at the back of
the bridge.
When the steam jets are not turned on air will pass through the bearers by natural
draught. The steam jets are however provided in order to insure a good draught of
air for the purpose of keeping the side bearers and all the working parts from over-
heating and the bearings clear of dust and small clinkers.
Instead of cutting the worms 21 on the shaft 20 they are, by preference, made
separately and hollow and each with projection at one end and recesses at the other
so that they interlock. They may be threaded on a light spindle or shaft whose
front end projects through the furnace front and is driven by the worm gear already
described. Fig. 10 shows such an arrangement.
The fuel can he fed to the furnace by means of a mechanical stoker with a ram
feed, such as shown, or by hand or by a combination of both. The fuel may however
be fed by gravitation from a running hopper. The method of feeding the fuel
forms no part of my invention.
The arrangement can be readily adapted for forced draught by closing the ashpit
at the front by an air tight door and by opening communication between the side
bearers and the ashpit either by making holes in the bottoms of the bearers or by
making the hollow fire bars with open ends. Additional air can be supplied by
means of additional steam induced blasts.
The openings 9 in the hollow fire bars are, by preference, lessened in number and
(or) size from the front of the furnace grate to the back. The first two or three of
the fixed bars may have holes made in them.
If so desired the fixed bars 1 may be dispensed with and simply a series of hollow
revoluble bars 2 used.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I consider
novel and desire to claim is :-
1. A furnace grate characterized by fire bars carried across the furnace and held
in position by longitudinal bearers said fire bars being caused to revolve slowly by
means of suitable mechanism so as to feed the fuel forward, by a rolling action,
continuously in one direction, substantially as herein before described.
2. In a furnace grate the application and use, in combination, of hollow revoluble
fire bars carried across the furnace, fixed fire bars arranged across the furnace and
between the revoluble fire bars, hollow longitudinal bearers for the fire bars, and
means for revolving the revoluble fire bars, substantially as hereinbefore described
with reference to the drawings annexed.
3. The construction or general arrangement and combination of parts of the
improved furnace grate substantially as hereinbefore described and shown on the
drawings annexed.
1000
H. D. FITZPATRICK,
100, Wellington Street, Glasgow, Agent.
H. D. FITZPATRICK,
100, Wellington Street, Glasgow, Agent.