Improvements in and relating to the Production of Forced Draught in Steam Boiler Furnaces.
Year: 1888

page_text: COMPLETE
SPECIFICATION.
Improvements in and relating to the Production of Forced Draught
in Steam Boiler Furnaces.
I, ANDREW MINNES, of 41 Princes Street, Ardossan, Ayrshire, Chemist, do
hereby declare the nature of my invention and in what manner the same is to be
performed to be particularly described and ascertained in and by the following state-
ment in writing, reference being had to the accompanying Two Sheets of Drawings
and to the letters and figures marked thereon that is to say :-
This Invention has reference to improvements in and relating to the production of
forced draught and improved combustion in steam boiler furnaces, by gaseous fuel or
vapor, either alone, or in combination with compressed air, or air and steam; and
comprises new or improved constructions, or arrangements and combinations of appli-
ances, consisting of a gas producer for generating the gas or vapor, and pipes, valves,
nozzles, and fittings for leading the said gas and injecting same along with com-
pressed air at the fire or flame bridge, or at other parts of the furnace, to combine
with and consume the combustible or volatile gases or vapor from the coal fire, and
prevent the formation or emission of smoke, while increasing the general draught
of the furnaces, and air to consume the fuel.
And in order that the nature and novelty of my invention, and the manner of per-
forming or carrying the improvements into effect or practice may be properly
understood, I have hereunto appended Two explanatory sheets of Drawings, in which
Figures 1 and 2 on Sheet 1 represent a sectional elevation and a plan respectively of
a gas producer for generating the gas to be injected into the furnaces, and constructed
and operated as will hereinafter be described. Figures 3 and 4 on Sheet 2 show a
longitudinal section, and an end view half in section taken near the flame bridge,
respectively, of a three furnace marine steam boiler, as fitted with my new arrange-
ments of appliances for injecting jets of gas and compressed or atmospheric air at the
fire or flame bridges of the furnaces. While Figure 5 is a sectional plan corresponding
to Figure 3 but taken at the irregular line 1-1 of Figure 4, with the furnace doors
and bars as removed. And Figure 6 shows a sectional elevation of the gas and air
combining jet nozzles c, e, for causing the draught and combustion in each furnace, to
a larger scale than shown in Figures 3 to 5. And Figure 7 shows.a plan of a flat
form of combining nozzle.
Referring to sheet 1 of these Drawings.-The gas producer herein shown consists
of a vertical combustion chamber or furnace vessel A, preferably of cylindrical shape
as shown, fitted with a fire grate A' at its lower end, and filled with coke or other fuel
through a hopper A' at its upper end. This hopper A is secured to the vessel A
through the annular neck ring A, these parts being each secured by rivets or bolts.
A sliding shutter or valve A is fitted between the hopper A' and the neck part A"
so as to feed in a charge of coke or fuel from time to time from the hopper A2, which is
fitted with a lid A, to prevent air getting in while feeding in the fuel. An outer
annular vessel a is riveted to the upper part of the vessel A to act as a gas or vapor
receiver or reservoir, the gas generated in the vessel A passing up through the coke
and into the vessel a through the openings a' in the upper part of the casing of the
vessel A. A drawing off branch a' and two way cock or valve a" are fitted to the side
of the vessel a through which a regulated quantity of the gas can be drawn through the
branch a³ or a, for being injected into the furnaces as will hereinafter be described.
Steam and air or steam, oil, and air are injected into the lower part of the gas
producer A above the furnace bars A', the steam being forced in through a branch b
and central nozzle to a pipe B and controlled by a screw regulating hand spindle
valve B¹, while the oil when it is used, is admitted in a regulated quantity to the
central pipe B by the branch 611 and nozzle &³, and the quantity controlled by the screw
regulating hand spindle valve B'. The oil will be allowed to drop from its nozzle

page_text: pipe bin small regulated quantity, and be carried and sprayed by the steam jet from
the nozzle b¹ through the common central pipe B right into the incandescent fuel
above the furnace bars A¹. A regulated supply of atmospheric, or of compressed, air
is also admitted to the producer A, through a knee branch valve chest 3, 11, leading.
into the central chamber B³ which carries the steam and oil nozzles b¹, 62, the branch 6
being fitted with a hand regulating valve B". The steam jet passing through the
nozzle b, b', will thus draw both the oil and air into the producer-chamber A to mix
zith the coke or fuel which would be lighted and made incandescent in the vessel A,
and carbon monoxide and other combustible gas or vapor will be generated and pass
through the apertures a¹ to the reservoir vessel a from whence it will be drawn off
through the regulating valve all to the furnaces, as will hereinafter be described, and
all as indicated by the arrows in the Figures.
The fire-bars A would preferably be such as would oscillate when required to allow
any clinkers or burnt products to pass down through them; and water may be placed
at A' in the ashpit at the bottom of the vessel A which would be heated by the waste
heat or products passing down and generate steam or vapor which would ascend up
the vessel A; and a door A is fitted at the side of the closed ash pit A' for removing
ashes or waste products of combustion from time to time, while a plug door &* is fitted.
above the fire grate A¹ for inserting a rod to poke up the fire or clear the fire bars, or
light the fire when so desired.
Referring to Figures 3, 4, and 5 on Sheet 2 the gas generated in the producer A a,
Figures 1 and 2, is led by a pipe from the branch a³, or a¹¹¹, to a common supply
pipe C either at its own pressure, or preferably assisted by a fan, Roots or other
blower. The pipe C has branch pipes C³ C², U³, which lead the gas to horizontal
conveying pipes c¹, c², e³, leading to the fire or flame bridge D of each furnace D', D², D³,
and from thence the gas would be injected amongst the combustible gases of the
furnaces through the horizontal branches c, and vertical annular nozzles c, e,
two of these nozzle pipes being shown in the side furnaces D¹, D³, and one in the
central furnace D2, although more may be used when desired. Each of these gas
pipes C, C2, C3, is fitted with hand controlling valves d¹, d², d³, respectively, to
regulate the quantity of gas passing into each furnace, and for shutting off the supply
from any or all of them when so desired.
e
Compressed air from the reservoir of an air compressing engine, or from a fan or
other blower, or it might be atmospheric air, would be led to a common supply pipe E,
from which branches E', E², E³, would lead to horizontal longitudinal pipes e, e², es,
and, conduct the air to the fire or flame bridges D, from which it would be led by
horizontal pipes e, to vertical branches leading to the central nozzle of each gas
and air nozzle c, e, and be injected in a combined mixture with the gas from the
annular surrounding nozzles c amongst the combustible gases and products of com-
bustion in the furnaces, so as to draw these from the furnaces D1, D2, D3, and burn
them in their passage through and behind the bridges D in the flame combustion
chamber D, all as indicated by the arrows Figures 3 to 5. The branch air
pipes E¹ E³, E³, would each be fitted with hand controlling valves f¹, ƒ³, ƒ³,
respectively, which would regulate the quantity of air passing into each furnace,
and shut the supply off from any or all of the furnaces when so desired. The.
compressed or atmospheric air may be heated in chambers formed of a number of
tubes in the chimney uptake flue, or in a chamber in front of the fire before being led
to the fire bridges D, of the furnaces. When only one set of gas and air jet nozzles c, e,
is used at the fire or flame bridge D of the furnaces, as shown in the central
furnace D, short tapered flues D', of fireclay or. other material would preferably be
built into the brickwork D surrounding these, so as to bring them more directly in
contact with the products of combustion from the coal fuel; but when two or more sets
of these jet nozzles c, e, are used, these flues D may be made much wider or dispensed
with. The jet nozzles c, e, may be formed with round orifices, as in Figure 6, or with
flat orifices as shown in plan Figure 7, and would be oovered in with a coating of fire-
clay, ganister, or silicious material to protect the metallic parts from being burnt
away by the flames at the fire-bridges D,

page_text: Instead of generating the gas in and leading it from a vertical generator as in
Figures 1 and 2 Sheet 1, by another arrangement of my improvements the generator A
is constructed and set horizontally, or at a slight angle, in the front uptake chimney
flue F as dotted-in in Figures 3 and 4 sheet 2. In this arrangement no fire-bars A¹
are used, and the gas generating vessel A which is filled with coke or other fuel is
heated or superheated by the waste products of combustion passing from the furnace
through the uptake flue F, to the chimney. The steam, oil, and air branches 61, 62, 63,
are fitted at the one or lower end of the vessel A, outside the uptake flue F, and a
branch, provided with a door or shutter is also fitted at this end to periodically
remove any consumed coke or ashes by a scraper or otherwise, from the vessel A
and the fire is lighted through this branch 65; and a small plug door is fitted at.
this end also for passing a rod through to poke up the fire. While the feeding
hopper A for the coke is fitted at the opposite or upper end of the vessel A as also
the gas collecting chamber or reservoir a, and a hinged door A³ for pushing the coke
down, all outside the uptake flue F; and the gas would be drawn off from this chamber a
through a branch and valve at a³, to the pipes C, leading to the furnace or flame
bridge D, all otherwise in a substantial manner to that already described in reference
to the Figures 1 to 5.
"
"
Instead of generating the gas in the producer A, it may be generated in a Siemens'
or other gas producer, and led to the pipes C, and injected into the furnace all other-
wise substantially as described in reference to Figures 3 to 7.
When only required to produce forced combustion in single furnaces or boilers, the
producer A may be made in the form of a tube or tubes A placed above the furnace
bars of the boiler, as shown in Figure 8 or at the level of and to form both the producer
or producers A and furnace bars as shown in Figures 9 and 10, and be protected
from being burnt away by a covering of fireclay, ganister, or other silicious material;
and be filled with coke or fuel and have steam and air or oil saturated steam, and
air injected at the front end and the gas led away at the other end to the delivery
nozzles at c at the flame bridge D, which in this case might be hollow, and be
otherwise substantially the same as that shown and described in reference io Figures 3
to 5.
Instead of generating gas as described, petroleum and vapor, or petroleum and
steam may be generated in a separate boiler or vessel and be led to the gas con-
veying pipes and be injected through the nozzles c, e, all otherwise substantially
as already described. And when petroleum vapor is used, instead of the gas, it and
the air may be led and injected through the nozzles c, e, at other parts of the furnaces
as well as at the flame bridges D, such as at the front part of the furnace.
By these improvements the force of the gas, or the petroleum vapor, and the air,
from the combining nozzles c, e, will produce a strong draught of air through the fire
and up the flame tubes, and consume all smoke and ensure complete combustion
of all volatile hydrocarbons, and thus promote economy of fuel; while under this
new system complete control of the furnaces will be obtained to give any desired
regulated draught or heat.
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
claim is -
First. The construction, or general arrangement and combination, of appliances for
producing forced draught and combustion in steam boiler furnaces by gas or gas and
air, substantially as herein described in reference to and shown in the accompanying
Drawings.
Second. The system, or mode and means, of producing forced draught and com-
bustion, in steam boiler furnaces, consisting in generating gas or vapor from a
combustible mixture of steam and air, or steam oil, and air, and incandescent coke
or fuel, or petroleum vapor within a close vessel, and leading or forcing same to
pipes which distribute the gas or vapor through branches and injecting nozzles to the
furnaces, either alone or in combination with compressed or atmospheric air led by

page_text: pipes to the injection nozzles, the whole being controlled by regulating valves, and
operated substantially as herein described, in reference to and shown in the
accompanying. Drawings.
Third. In a system for producing forced draught and combustion in steam boiler
furnaces, the generating of gas or vapor from a combustible mixture of steam and air,
or steam oil, and air, and incandescent coke or fuel within a close vessel placed and
heated in the uptake flue to the chimney, or over the furnace bars, substantially as
herein described, in reference to and shown in the accompanying Drawings.
· Dated the 1st December 1888.
W. R. M. THOMSON & Co.,
Agents.