IMPROVEMENTS IN APPLIANCES FOR CREATING ARTIFICIAL DRAUGHT AND SECONDARY SUPPLY OF AIR IN STEAM GENERATORS
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
I NEVILLE EVANS, of Woodstock, Waterloo, near Liverpool in the County of
Lancaster, Engineer do hereby declare the nature of the said Invention for
IMPROVEMENTS IN APPLIANCES FOR CREATING ARTIFICIAL DRAUGHT AND
SECONDARY SUPPLY OF AIR IN STEAM GENERATORS, to be as follows:-
My Invention relates to certain improved construction and arrangement of that
class of appliances which are used for creating an artificial draught in the furnaces
of steam generators and a secondary supply of air into the combustion chamber of
such steam generators.
.
My Invention consists in a certain construction of apparatus herein after more
particularly described for distributing a blast of air forced by steam under the
furnace bars in an open ashpit of steam generators and in a certain arrangement
in connection with the lower tubes of such steam generators whereby a quantity of
air is caused to pass from the front of the boiler through such tube, or tubes into
the combustion chamber of such steam generator.
An apparatus constructed according to my Invention for creating the draught
under the furnace consists of a hollow elbow trunk of cast iron, or other suitable
metal. At the bend of the trunk there is provided a nozzle for the supply of
steam. This nozzlo projects inwards some distance into the delivery portion of the
trunk with its nozzle placed in the direction of the line of blast. The delivery
orifice of the trunk is formed of a series of corrugations, which are designed to
distribute the blast of air and steam in vertical streams under and in line with the
firo bars.
The apparatus are fitted one on each side of the ashpit and immediately under.
the doad plate and fire bars with their mouths placed outwards from the furnace
ashpit. The discharge orifices are splayed towards the centre of the furnace so as
to distribute the blast of air and steam. The nozzles are supplied by suitable
steam pipes leading from the boiler.
The secondary supply of air to effect the complete combustion of the gases in the
combustion chamber is foreed through one, or more of the tubes of the generator.
This is effected by providing a hollow elbow trunk or trunks and attaching it on
to the under part of the smoke box, the mouth opening into the stoke hole and just
above the furnace and the delivery end fitting over the end of the tube, or tubes,
19

page_text: These elbows are provided with steam nozzles in manner as previously described
in reference to the under grate elbow trunk. By positioning the elbow trunk
above described, namely just above the furnace and also by the use of steam the
air drawn into the elbow will be considerably heated, thus all danger of injury to
the combustion chamber plates is obviated. At the back end of the tubes which
are supplied with the blast trunks, I provide a distributor nozzle bolted onto the
tube plate and fitting over the tube ends. This nozzle is splayed out so as to
distribute the secondary supply of air and to effect an intermixing of such air with
the gases in the combustion chamber.
The apparatus above set forth are described as applied to cylindrical multitubular
boilers of the marine type. It must be understood that the apparatus which is
applied to the furnace can be applied to other types of marine boilers. Also in
some cases it may be found convenient instead of forcing the secondary supply of
air through the tubes to place the blast apparatus upon the outside shell and form
a passage through the shell to the combustion chamber by a tube, or tubes through
which the air is forced.

page_text: COMPLETE SPECIFICATION.
I NEVILLE EVANS, of Woodstock, Waterloo, near Liverpool, in the County of
Lancaster, Engineer do hereby declare the nature of the said Invention for
IMPROVEMENTS IN APPLIANCES FOR CREATING ARTIFICIAL DRAUGHT AND
SECONDARY SUPPLY OF AIR IN STEAM GENERATORS, 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 certain improved construction and arrangement of that
class of appliances which are used for creating an artificial draught in the furnaces
of steam generators and giving a secondary supply of air to the combustion chamber
of such steam generators.
My Invention consists in a certain construction of apparatus herein after more
particularly described for distributing a blast of air forced by steam under the
furnace bars in an open ashpit of steam generators and in a certain arrangement in
connection with the tubes of such steam generators whereby a quantity of air is
caused to pass from the front of the boiler through such tube, or tubes into the
combustion chamber of such steam generator.
An apparatus constructed according to my Invention for creating the draught
under the furnace consists of a hollow elbow trunk or trunks of cast iron, or other
suitable metal. At the bend of the trunk there is provided a nozzle for the supply
of steam. This nozzle projects inwards some distance into the delivery portion of
the trunk with its nozzle placed in the direction of the line of blast. The delivery
orifice of the trunk is formed of a series of corrugations or slots which are designed
to distribute the blast of air and steam in vertical streams under and in line with
the fire bars.
The apparatus are fitted one on each side of the ashpit and immediately under
the dead plate and fire bars with thoir mouths placed outwards from the furnace
ashpit. The discharge orifices are splayed towards the centre of the furnace so as
to distribute the blast of air and steam. The nozzles are supplied by suitable
steam pipes leading from the boiler.
The secondary supply of air to effect the complete combustion of the gases in the
combustion chamber is forced through one, or more of the tubes of the generator.
This is effected by providing a hollow elbow trunk, or trunks and attaching it to
the under part of the smoke box, the mouth opening into the stoke hole and just
above the furnace and the delivery end fitting over the end of the tube or tubes.
These elbows are provided with steam nozzles in manner as previously described
in reference to the under grate elbow trunk. By positioning the elbow trunk
above described, namely just above the furnace, and also by the use of steam the
air drawn into the elbow will be considerably heated, thus all danger of injury to
the combustion chamber plates is obviated. At the back end of the tubes which
are supplied with the blast trunks, I provide a distributor nozzle bolted to the
tube plate and fitting over the tube end or ends. This nozzle is splayed out so as
to distribute the secondary supply of air and to effect an intermixing of 'such air
with the gases in the combustion chamber.

page_text: The apparatus above set forth are described as applied to cylindrical multitubular
boilers of the marine type. It must be understood that the apparatus which is
applied to the furnace can be applied to other types of marine or other boilers.
Also in some cases it may be found convenient instead of forcing the secondary
supply of air through the tubes, to place the blast apparatus upon the outside shell
and form a passage through the shell to the combustion chamber by a tube, or
tubes through which the air is forced.
The beforegoing being the nature object and purposes of my Invention, I will now
proceed to describe more in detail how the same may be carried out into practical
effect and for that purpose I have hereunto attached two sheets of Drawings making
a part of this Specification, which Drawings are marked with letters and figures of
reference corresponding to those used in the following description, like letters and
figures being used to denote the same, or corresponding parts throughout the various
views and figures."

page_text: under the furnace bars and for giving a secondary supply of air to the combustion
chamber. A is the hollow elbow trunk constructed as previously described in
reference to Figures 1. 2. 3. 4 and 5. It is fitted in front of the ashpit a of the
steam generator and under the dead plate b and provision is made for carrying
the pricker bar d. The steam nozzles Ċ are supplied with steam by the pipes e
which are fitted and led in manner such as shown at Figures 12 and 13, or
equivalently. The pipes e are provided with cocks, or valves h and i; the cocks,
or valves h being for regulating and controlling the supply of steam to the nozzles O
of the trunk A and the cocks, or valves i being for regulating and controlling the
supply of steam to the nozzles H of the secondary supply trunk E. A cock, or
valve k is also provided between the steam generator and the end of the pipe e
for controlling the supply of steam to the pipe e.
By positioning the elbow trunk E in the smoke box on the front end of the
tube F of the steam generator and also by the use of steam for propelling the air,
the air drawn in and forced through the tube F and through the distributing
mouthpiece J into the combustion chamber m will be considerably heated and thus
all danger of injuring the plates of the combustion chamber m is obviated.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what
I claim is
First The combination of a hollow trunk (such as A) provided with a corrugated
delivery orifice D which directs the air and steam in parallel streams under and
along the fire bars as set forth with reference to Figures 1, 14, 2, 3, 4 5 6, 7 and 8
of the annexed Drawings.
Second The particular construction of apparatus as set forth with reference to
Figures 1, 2, 3 and 5 of the Drawings.
Third The particular construction of apparatus as set forth with reference to
Figure 1 of the Drawings.
Fourth The particular construction of apparatus as set forth with reference to
Figures 6, 7 and 8 of the drawings.
Fifth The combination of a steam jet with one, or more of the tubes F of a boiler
as set forth for the purposes described.
Sixth The construction and arrangement of apparatus as set forth with reference
to Figures 9, 10 and 11 of the Drawings.
Dated this thirteenth day of May 1885.