AN IMPROVED GAS PRODUCER AND BOILER FURNACE
Year: 1885

page_text: BENJAMIN HOWARTH THWAITE Civil Engineer and Consulting Chemist Dart-
mouth Villa Fountain St Tranmere Cheshire do hereby declare the nature of
my invention for AN IMPROVED GAS PRODUCER AND BOILER FURNACE to be as
follows:-
My improvement consists in novel arrangements for the generation of gas from
carbonaceous-fuel and its combustion, in accordance with recent discoveries by
myself and Frederick Siemens of the manner by which the most effective and
complete radiation of the heat-resulting from combustion can be obtained-and by
which the most complete action of combustion can be effected-in this instance for
generating steam.
In order to further ensure a complete and intensely active action of combustion-
I utilise the principle of recuperation to raise the temperature of the air-required
to support combustion, to as near the temperature of the gas as possible-I also
cool the gas before its combustion by bringing part of the air required to support
combustion in contact with the tubes through which I make the gas traverse.
In the generation of the gas I compell the volatile hydrocarbons to traverse
a considerable depth of fuel before they are permitted to mix with the occluded
carbon monoxide gas.
The following is a description of my arrangements, I construct the furnace for
generating the gas either immediately under or closely alongside the steam
generator. I make the furnace preferably square in plan but it may be rectangular
or circular. I use the fire and clinkering bar arrangement which is used in the
gas producers of the Bower-Barff Rustless Iron furnaces, but with tight fitting
ashpit doors fastened with crossbar and screw, The sides of the furnace I construct
of refractory materials with an outside casing of wrought or cast iron leaving a
cavity between the casing and the brickwork, I connect this cavity by means of
equally distributed orifices at the lower portion of the furnace walls with the
outside air, and also with the space underside the firebar, These latter outlets
I provide with simple spring valves which will not allow the air when forced
under the firebars by Blowers to enter into the cavity, until a given pressure is
established under the grate or firebars.
I construct the furnace of such a depth as will permit me to have a depth of
fuel equal to 5 feet, I turn a hollow bridge over the centre of the furnace, this

page_text: I construct of refractory material shielded with iron, and fix it in such a way that
when the fuel is fed into the furnace the underside of this bridge in which are
formed the outlet openings, is at least 12 inches below the upper surface of the
fuel, on each side of. this hanging outlet bridge I provide fuel charging hoppers, in
order to prevent the ingress of air into the furnace through these hoppers I provide
them with duplicate doors one of which when opened allows the fuel to fall into
the furnace whilst the other door is closed, and vice versa when new or fresh fuel
is placed in the hopper.
In constructing the outlet bridge, I leave openings on its underside for the escape
of the gas which is then collected by a flue and directed into orifices in the arch
covering the collecting flue, each orifice is provided with a fireclay tube burner,
around which circulates the air drawn from the cavities in the walls and already
described, the air becomes considerably heated from contact with the tubes and the
gas is correspondingly cooled from the abstraction of its heat by the air, and both
air and gas become as near as possible the same temperature.
Immediately over the upper ends of the gas burner tubes, which I construct
about 3 inches in diameter and of some refractory material, is the circular chamber
in which is the zone of initial gaseous combustion,-air from the cavities in the
walls meets the gas which is also supplied with heated air from the air inlet tubes,
equally distributed around the combustion zone chamber. The latter supply of
air is heated by recuperation, viz by the heat from the products of combustion as
afterwards described.
The air from the cavities in the walls is led into the space around the gas burner
tubes by means of pipes built in the brickwork supporting the cast iron circular
framework, which supports the steam generator, and in which are fixed the
recuperator or air heating tubes, the circular framework also forming the collecting
flue for the products of combustion which are led into the chimney flue, in
passing through the collecting flue the products of combustion give up their
remaining heat to the air tubes.
The circular cast iron framework supporting the steam generator and forming
the collecting flue I make in segments, one of which I make movable in order that
it may be withdrawn for the purpose of repairing burner tubes but the other
segments may in case of necessity be also removed.
302

page_text: I BENJAMIN HOWARTH THWAITE Civil Engineer and Consulting Chemist Dart-
mouth Villa 23 Fountain St Tranmere Cheshire do hereby declare the nature of
my invention for IMPROVED GAS PRODUCER AND BOILER FURNACE and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :—
My improvement consists in novel arrangements for the generation of gas from
carbonaceous fuel and for its combustion in accordance with the recent discoveries
of myself and Frederick Siemens of the manner in which the most effective
radiation resulting from combustion can be obtained, and by which the most
complete action of combustion can be effected particularly for generating steam.
In order to further ensure a more complete action of combustion I utilise the
principle of recuperation to raise the temperature of the air required to support
combustion as near as possible to the temperature of the gas.
I also cool the gas before its combustion by bringing part of the air required
for combustion in contact with the tubes through which I make the gas traverse
or pass through.
In the generation of the gas I compell the volatile hydrocarbons to traverse or
pass through a considerable depth of fuel before they are allowed to mix with the
other carbon-monoxide gases produced.
The following is a description of my arrangements I construct the furnace for
generating the gas immediately under or closely along side the steam generator,
I make the furnace preferably square in plan, but it may be rectangular or circular,
I use the fire bar and clinker bar arrangement which is used in the gas producers
of the Bower-Barff Rustless Iron furnaces, but provided with tight fitting doors,
fastened with cross bars and screws, The sides of the furnace or producer
I construct of refractory material, with an outside casing of wrought or cast iron
having a cavity between the casing and the brickwork, I connect this cavity by
means of equally distributed orifices at the lower portion of the furnace walls, with
the outside air, and also with the space or ashpit under the firebars.
These orifices are provided with simple valves which will only allow the air
under pressure (and forced under the firebars by Blowers of the Köerting, Siemen's
or fan type) to enter the cavity around the furnace, when a given pressure is
established under the grate-or when an excess of blast of air above that required
for the generation of the combustible gases-is established under the grate such
excess of air blast is used for the combustion of the gas produced.
I construct the furnace of such a depth as will permit me to have a depth of fuel
equal to five feet-or thereabouts.
I turn a hollow bridge over the centre of the furnace, this I construct of
refractory material partly shielded with iron, and fix it in such a way that when
the fuel is fed into the furnace the underside of this bridge in which are formed
the outlet openings for the escape of the gas, is at least twelve inches below the
upper surface of the fuel-when such fuel is at a depth of 3 feet on the bars.
On each side of this hanging bridge I provide fuel charging hoppers; in order
to prevent the ingress of air into the furnace through these hoppers, I provide
them with duplicate doors one of which when opened allows the fuel to fall into
the furnace whilst the other door is closed, and vice versa when new or fresh fuel
is placed in the hopper,

page_text: In constructing the outlet bridge I leave openings in its under side for the
escape of the gas which is then collected by a flue, and directed into an orifice or
orifices in the arch covering the collecting flue when I burn or consume the gases-
immediately over the gas-producer as for instance when I place my patent vertical
boiler No 1201 AD 1885-immediately over the gas producing furnace described-
I provide each of the orifices in the arch over the collecting flue with a burner tube
of fireclay or other highly refractory substance.
Around these burner tubes air blast from the cavities in the walls already
described circulates, the air becomes heated in contact with the tubes, and the gas
becomes correspondingly cooled from the abstraction of its heat by the air, and both
air and gas become as near as possible of the same temperature-Immediately over
the upper ends of the gas burner tubes which I construct about 3 inches in diameter,
is the zone of gaseous combustion, air from the cavities as already described, meets
the gas
which is also supplied with air from the air inlet recuperator tubes equally
distributed around the combustion zone, the latter supply of air is also heated by
recuperation or by the products of combustion as described in my patent No 1201
AD 1885.
The air from the cavities is led into the space around the gas burner tubes by
means of pipes built in the brickwork supporting the cast iron circular framework
which supports my patent steam generator as described in my patent specification
No 1201 A.D. 1885 and carries the recuperator air tubes and also forms the flue
for leading the products of gaseous combustion into the chimney.
When the gas is required for combustion in a steam generator or furnace placed
close alongside the gas producers the gas is led by means of a pipe connected to
the orifice provided in the gas collecting flue, the gas may be led above or under
ground to the position where it is to be consumed, The excess of air blast from
the underside of the fire grate may be led from the equally distributed and
valvular orifices already described, by means of an underground or over ground
conduit, to the point of combustion of the gas.
1
The accompanying drawings are intended to form part of this specification and
to illustrate practical modes of carrying this invention into effect, but I do not
limit myself to the precise forms and details shewn as they may be varied without
departing from the nature of my invention.
Figure 1 and 2 are vertical sections and figure 3 an elevation of the gas
producer, figure 4 is a plan in section through gas producer just above the level of
the firebars.
Figure 5 is a plan in section through collecting flue and shewing outlet bridge.
Figure 6 is a plan in section through air blast supply tubes and gas burner
tubes.
Figure 7 is a section through gas producer shewing the application of the gas
produced for firing steam boilers placed alongside; and also shewing conduits or
pipes for distributing air blast and gas.
Figure 8 is a section of figure 7 on line a-b.
Figure 9 is a plan taken through collecting flue.
Figure 10 is a section through combustion arrangement at c. d. g. fig. 7.
Figure 11 is a section of fig. 7 at e f-shewing air distributing arrangement.
Figure 12 & 13 are alternate combustion arrangements.
The furnace a see figs. 1 and 2 is lined with refractory material, is the double
clinkering and ashpit door made tight fitting by means of a crossbar and screw,
c is the junction to which is connected the air blast or steam blower d.
The valvular air outlet holes for the escape of the excess of air blast under the
ashpit are shewn at e.
fare the firebars g the bearers for sustaining the clinkering bars.
h is the bridge provided with outlets for the escape of the gas, i are the fuel
charging doors are the duplicate doors.
the ana collectioe
+

page_text: r Central gas burner tube in figs. 10 & 11.
s Small refractory gas burners screwed or otherwise attached to central gas tube.
t Refractory tubes for distributing air to each of the small burners 8.
u Central air distributor. u¹ air blast regulator.
v Air regulating valve v circular slide air valve.
w Air blast tuyere fig. 12.
x gas tuyere fig. 12.
y focus of direction of line of gas and air tuyeres fig. 12.
Forced air blast supply pipes.
In commencing work the ashpit doors an chimney valves are kept open and
a fire is lighted in the grates in the ordinary manner until a depth of fuel equal
to a least 4 feet is attained-and as soon as steam is raised the ashpit doors are
closed, and steam is turned on at the air blowers, the coal or other fuel is then
gradually fed into the furnace until it is completely filled as shewn on drawings,
The volatile gases given off by the partially decomposed fuel are compelled to
descend through the incandescent portion of the fuel-and thus become fixed or
permanent, escaping through the openings in the bridge-where they become
mixed in the collecting flue with the carbon monoxide gases.
Having now particularly described and ascertained the nature of my invention
and in what manner the same is to be performed I declare that what I claim is
the following
1st The form of gas generator in which the gases are drawn off at the lower
level or at the incandescent portion of the fuel by means of a central hollow
hanging bridge which dips into the centre of the furnace, and through which the
gases can escape into a collecting flue-which may be immediately under the
burner tubes substantially as herein shewn and described.
2nd The utilisation of the excess of air blast over that required for the production
of combustible gases in the producer for the purpose of supplying air to support
combustion substantially as described.
3rd The use of openings around the ashpit provided with valves which will only
allow the air blast to pass through them after a given pressure is established under
the grate.
4th The manner of utilising heat radiated in the ashpit for heating the air for
the combustion of the gases produced substantially as described and shewn.
5th The method of collecting the gases produced, and the system of gas burner
tubes substantially as described.
6th The manner of distributing the air to the gas burner tubes substantially as
described.
7th Providing coal charging doors on each side of the hanging outlet bridge
substantially as described.

page_text: TH