Improvements in Means or Apparatus for Producing an Artificial Draught or Current of Air or Gas in Furnace Flues, Chimneys, Ventilating Shafts, and the like.
Year: 1891

page_text: Date of Application, 27th Apr., 1891
Complete Specification Left, 27th Jan., 1892-Accepted, 27th Feb., 1892
PROVISIONAL SPECIFICATION.
Improvements in Means or Apparatus for Producing an Artificial
Draught or Current of Air or Gas in Furnace Flues, Chimneys,
Ventilating Shafts, and the like.
I JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of
Middlesex Gentleman, do hereby declare the nature of this invention, which has
been communicated to me from abroad by La Société Geneste Herscher and Cie. of
42 Rue du Chemin Vert, Paris in the Republic of France, Engineers, to be as
follows:-
The arrangements heretofore employed for obtaining and exhausting action in
a flue by injecting fluid such as air or steam do not utilise the action of the jets to
the best advantage. The loss of pressure that takes place between the compressing
apparatus and the jet is frequently so great as to render this otherwise useful method
of producing a forced or artificial draught incapable of being employed with
economy.
According to this invention arrangements are employed which limit the
interference with the free passage in the flues to the simple insertion of injector
nozzles passing through the side and applied against the inner surface being in
direct communication with one or more external compressed air chambers placed in
proximity to the nozzles. By these means pipes or conduits in the interior of the
Aue are entirely dispensed with and on the other hand the initial pressure of the
air is maintained and the delivery is rendered regular and uniform.
In carrying out the invention in practice injector nozzles or orifices are arranged
in a circle in the interior of the chimney or flue in such a position as to deliver a
stream of air in the direction in which the current is to be produced and are directly
connected with one or more external compressed air chambers which may entirely
surround the chimney and form part thereof or may be entirely independent or
separated from the flue or chimney in certain cases but in general it is desirable to
make the connections between the injector and the reservoir as short as possible.
The complete apparatus comprises a generator of compressed air or air compressing
apparatus a compressed air chamber or chambers and pipes or conduits for the
distribution of the air under pressure and should be so arranged as to bring the
reservoir as near as possible to the points where the injectors act avoiding all
intermediate tubing between the said injectors and the reservoir.
In the case of a marine boiler furnace for example a series of injector nozzles
directed upwards is arranged at or near the base of the funnel and these nozzles
communicate with an annular compressed air chamber surrounding the lower part
of the funnel. A fan or blower supplies air under pressure to this chamber so
that the artificial draught can be brought into action or stopped as required. These
arrangements for creating an artificial draught can also be employed with advantage
in dealing with acid or corrosive gases or vapours as the projecting part of the
nozzles which may be made of or coated with any suitable acid proof material is
all that requires to be protected from the corrosive action of the vapours which do
not come in contact with the other parts of the apparatus. The arrangement is
evidently equally applicable to chimneys.or flues constructed in a vertical horizontal
or inclined direction. The air compressing apparatus not being brought in contact
with the current of air or vapour produced by the injectors the apparatus is also
capable of being employed with advantage for producing currents of air in
ventilating shafts or the like in which the air is charged with floating particles of
fibrous or other matter and a number of ventilating shafts, flues or chimneys may
be combined with one air compressing apparatus by means of suitably arranged

page_text: main and branch pipes. Any suitable number of injector nozzles may be employed
or the compressed air may be delivered into the chimney or flue from one or more
orifices of annular elongated or other suitable shape capable of directing the stream
or jet of air in the required direction..
Dated the 27th day of Anril 1801
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, Agents.
COMPLETE SPECIFICATION.
Improvements in Means or Apparatus for Producing an Artificial
Draught or Current of Air or Gas in Furnace Flues, Chimneys,
Ventilating Shafts, and the like.
I JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of
Middlesex Gentleman do hereby declare the nature of this invention (which has
been communicated to me from abroad by La Société Geneste Herscher and Cie. of
42 Rue du Chemin Vert Paris in the Republic of France Engineers) and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement :--
The arrangements heretofore employed for obtaining an exhausting action in a
flue or the like by injecting a fluid in the direction in which the current is required
to flow do not utilise to the best advantage the exhausting action produced by the
jets of compressed air for example. The loss of pressure that takes place in
traversing the interval between the air compressing apparatus and the injector
nozzles employed to produce the exhausting action is frequently so great as to
render this valuable method of producing a forced or artificial draught incapable
of being employed with economy in practice. On the other hand it is inconvenient
to employ any bulky apparatus that would be liable to encumber or contract the
sectional area of the chimneys or flues.
According to this invention arrangements are employed which limit the
interference with the free passage in the flues to the simple insertion of injector
nozzles passing through the sides or walls and applied against the inner surface
and placed in direct communication with one or more external chambers
containing compressed air or the like placed in close proximity to the said nozzles
as hereinafter more fully explained with reference to the accompanying drawings.
By these means pipes or conduits in the interior of the flue in which the current is
to be produced are entirely dispensed with and on the other hand the initial
pressure of the air or fluid is maintained and the supply is rendered regular and
uniform or continuous.
By these means it is rendered possible to realise with certainty the desired
results which have heretofore been only imperfectly attained and the effect produced
is obtained under comparatively more economical conditions than is the case with
the means heretofore employed.
For the purpose of securing the several advantages hereinbefore specified an
improved arrangement of apparatus is employed according to this invention
consisting essentially of the following parts namely:-A series of injector nozzles
or orifices in the interior of the chimney or flue (being directly connected with one
or more external chambers from which they are supplied) and one or more compressed
air chambers surrounding the flue and being either made in one therewith or
completely independent or detached therefrom.
The annular collecting and distributing chamber for compressed air for example
(being formed by one or more vessels) may if required be situated apart from or
not in immediate contact with the outside of the Hue or chimney but in general it
is desirable to make the connections between the injector and the reservoir as short
as possible in order to obtain the best results. The combination of the parts which
in apparatus of this class as heretofore constructed comprises a generator of

page_text: compressed air or air compressing apparatus, a compressed air chamber, or
chambers, pipes or conduits for the distribution of the air under pressure and
injector nozzles situated in the flue or passage in which the artificial draught is to
be produced is according to the present invention so arranged as to bring the
compressed air reservoir as near as possible to the points where the injectors act
thus avoiding all intermediate tubing between the said injectors and the reservoir.
This combination of arrangements is susceptible of a great diversity of applications
and admits of being accommodated to the conditions necessary to maintain the
strength of the walls of the flues in which the draught or exhausting action is to
be produced or to the preservation of the integrity of the sectional area of the
passage provided for the escape of the products of combustion or other gases.
And in order that the said invention may be fully understood I shall now proceed
more particularly to describe the same and for that purpose shall refer to the several
figures on the annexed sheets of drawings the same letters of reference indicating
corresponding parts in all the figures.
Figure 1 of the accompanying drawings represents in vertical section an apparatus
according to this invention applied to a marine boiler flue or funnel and
Figure 2 represents this apparatus in plan, the funnel being in horizontal section.
Figures 3, 4, 5 and 6 are diagrams representing examples of modified forms of
construction of the nozzles and air chambers for this apparatus.
Figures 7 to 12 illustrate different applications and details of the invention as
hereinafter explained.
In the case of a marine boiler furnace flue for example as represented in
Figures 1 and 2 a series of injector nozzles A directed upwards is arranged at or
near the base of the funnel D being attached to the sides by flauges and bolts.
These nozzles communicating with an annular compressed air chamber B surrounding
the lower part of the funnel and being arranged as represented in the drawing do
not materially contract or obstruct the passage in the chimney or funnel D.
A fan or blower C supplies air under pressure to the chamber B so that the
artificial draught can be brought into action or stopped as required by simply
putting the blower in or out of action without other change in the working of the
furnaces.
In place of constructing the apparatus as represented in Figures 1 and 2 any
other suitable form of construction may be employed. Examples of such modified
constructions are given in Figures 3. 4. 5 and 6 of the drawings. The same letters
of reference being employed to mark the parts corresponding with the parts herein-
before described with reference to Figures 1 and 2 these figures will be understood
without further description.
These arrangements for creating an artificial draught can also be employed with
advantage in dealing with acid or corrosive gases or vapours as the projecting part
of the nozzles which may be made of or coated with any suitable acid proof
material such as vulcanite for example is all that requires to be protected from the
corrosive action of the vapours which do not come in contact with the other parts
of the apparatus.
Fig. 7 illustrates an example of this application of the invention which is here
represented in combination with the ventilating shaft or flue D of a chamber or
room E for treating acids generating light vapours. In this case the compressed
air chamber B is arranged outside the room at the base of the chimney and the
injector nozzles A are the only part that is exposed to the corrosive vapour escaping
through the chimney or shaft D.
Fig. 8 illustrates a similar application of the invention under conditions which
render it necessary to create a draught in a horizontal flue D the invention being
evidently equally applicable to chimneys or flues constructed in a vertical horizontal
or inclined direction. The air compressing apparatus not being brought in contact
with the current of air or vapour produced by the injectors the apparatus is also
capable of being employed with advantage for producing currents of air in
ventilating shafts or the like in which the air is charged with floating particles of

page_text: fibrous or other matter such as feathers dust ashes or soot for example which
would be liable to choke or clog any apparatus with which they come in contact.
A number of ventilating shafts flues or chimneys may be combined with one air
compressing apparatus by means of suitably arranged main and branch pipes. Any
suitable number of injector nozzles may be employed or the compressed air may be
delivered into the chimney or flue from one or more orifices of annular elongated
or other suitable shape capable of directing the stream or jet of air in the required
direction.
Figures 9 and 10 illustrate arrangements suitable for flues or the like which are
employed for air or fluids charged with particles of solid matter.
According to the arrangement illustrated in Figure 9. a series of flues or
chimneys D are each provided with compressed air chambers B supplied from a
main G and producing a current in the said flues or chimneys by means of injector
nozzles A.
Figure 10 illustrates an arrangement by means of which a similar effect is
obtained by placing one compressed air chamber B on a flue D' receiving the
discharge from the upper ends of all the flues or chimneys D.
The injector nozzles may be made of any suitable form and dimensions as may
be found most convenient for the apparatus in which they are employed and may
be made of metal or any other material. For example they may be constructed
as represented in Figure 11. In this case the nozzle A is formed by a bent taper
tube. This tube is formed with flanges A¹ enabling it to be attached to the
compressed air chamber and to the side of the chimney in which the draught is to
be created. The form illustrated in the drawing is evidently susceptible of a variety
of modifications. The injectors may be of cylindrical form or be provided with a
bell or flaring mouth or be of any shape best suited for the object in view.
In Figure 5 for example the orifice is represented as being of continuous or
annular form. This form has the advantage of reducing to a minimum the part of
the injector projecting into the chimney. With this arrangement the annular
injector enables the vein of air to have a minimum thickness for a given sectional
area for injection and it results that the extremity of the injector which serves to
direct the jet can be diminished in length without prejudice to the direction given
to the stream of air blown into the flue. Nevertheless an arrangement such as that
illustrated in Figure 11 is what is generally found most useful in practice.
The arrangements hereinbefore described may be applied to chimneys, conduits
or flues of any shape or material. For example they may be combined_with
chimneys terminating in an inverted cone or bell mouth (as represented at D' in
Figure 12) acting as a disperser this being an arrangement which admits of the
recovery of a great part at least of the force expended in order to obtain the
active pressure which a fluid is required to exert in escaping into the atmosphere.
The apparatus may be combined with any air compressing apparatus or blower
such as pumps with pistons, fans or the like but it is preferred to employ a good
fan (such as the "Ser" fan) working by centrifugal force. Having the important
advantages of simplicity economy and compactness this kind of apparatus also
possesses the advantage of producing the same useful effect as more expensive and
complicated machines with a relatively small expenditure of power. This result is
owing to the fact that this ventilator is more suitable than any other for supplying
the compressed air employed in apparatus according to this invention at the degree
of pressure most favourable for producing the desired draught or exhausting
action.
Having now particularly described and ascertained the nature of this inven
tion and in what manner the same is to be performed I declare that what I
claim is: :-
1. Producing an artificial draught or current of air or gas in furnace flues,
chimneys ventilating shafts and the like by means of injector nozzles inserted in
the sides or walls of the flue or passage in such a manner as to obviate obstructing

page_text: the passage or contracting the sectional area of the latter or diminishing the initial
or original pressure of the fluid injected substantially as hereinbefore described
with reference to the accompanying drawings.
2. In combination with flues chimneys ventilating shafts and the like a series of
injector nozzles (or an annular injecting orifice or orifices) receiving a supply of
air or other fluid under pressure direct from one or more external chambers
surrounding the flue or passage being either formed in one piece therewith or
independent therefrom substantially as herein before described with reference to the
accompanying drawings.
3. The several arrangements and combinations of means or apparatus for
producing an artificial draught or current of air or gas in furnace flues, chimneys,
ventilating shafts, and the like substantially as herein before described.
Dated this 27th day of January 1892.
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C., Agents.