Improved Means for Inducing Draught in Boiler Furnaces.
Year: 1891

page_text: Date of Application, 29th Aug., 1891
Complete Specification Left, 26th May, 1892-Accepted, 2nd July, 1892
PROVISIONAL SPECIFICATION.
Improved Means for Inducing Draught in Boiler Furnaces.
We, WILLIAM DONALD, and ROBERT HANNA DONALD both of the firm of
Hanna Donald & Wilson, Engineers, Abbey Works, Paisley, Renfrewshire, do
hereby declare the nature of this invention to be as follows:-
This invention has for its object the provision of improved means for inducing
draught in boiler furnaces more especially in connection with marine boilers in
order to obviate the undue tear and wear and other disadvantages attendant on the
use of forced draught.
To that end the invention consists in fitting in the uptake, funnel or chimney
leading from the boiler furnace a pipe or pipes through which air heated by the
waste heat of the products of combustion is forced or ejected under pressure. By
preference a number of pipes are employed and are formed into coils and placed
horizontally one over the other. The ends of the coils are carried through the
funnel and connected to a service pipe from a receiver or air compressor which may
be operated from the ships engines in the case of marine boilers.
Each coil has in it small orifices, or is fitted with nozzles through which the
compressed air heated in traversing the coils is ejected upwards through the uptake
or chimney to induce draught or increase the natural draught in the boiler furnace ;
and regulation of the induced draught is or may be provided for by fitting
valves on the service pipe or on the brauches connecting it to the separate coils in
the funnel.
Dated this Twenty-eighth day of August 1891.
CRUIKSHANK & FAIRWEATHER,
62, St. Vincent Street, Glasgow, Agents.
COMPLETE SPECIFICATION.
Improved Means for Inducing Draught in Boller Furnaces.
We, WILLIAM DONALD and ROBERT HANNA DONALD both of the firm of
Hanna Donald & Wilson Engineers, Abbey Works, Paisley, Renfrewshire 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 has for its object the provision of improved means for inducing
draught in boiler or other furnaces more especially in connection with marine
boilers in order to obviate the undue tear and wear and other disadvantages attendant
on the use of forced draught.
To that end the invention consists in fitting in the uptake funnel or chimney
leading from the boiler furnace a pipe or pipes through which air heated by the
waste heat of the products of combustion is forced or ejected under pressure. By
preference a number of pipes are employed and are formed into coils and placed
horizontally one over the other. The ends of the coils are carried through the
funnel and connected to a service pipe from a receiver or air compressor which may
be operated from the ships engines in the case of marine boilers..
Each coil has in it small orifices or is fitted with nozzles through which the
compressed air heated in traversing the coils is ejected upwards through the uptake
or chimney to induce draught or increase the natural draught in the boiler
furnace; and regulation of the induced draught is or may be provided for by

page_text: fitting valves on the service pipe or on the branches connecting it to the separate
coils in the funnel.
In the accompanying diagrams which illustrate our invention
Figure 1 is an elevation and Figure 2 a plan of part of a marine steam boiler B
showing horizontal helical air pipes or coils A and A' fitted at different points in
the uptake or chimney C from the boiler furnace air being supplied to either or
both coils by a service pipe D provided with valves d.
Figures 3 and 4 are elevations at right angles to each other and
Figure 5 is a plan of a boiler in which the air pipes or coils A A' are shown
carried in part vertically and in part horizontally the lower portion being in the
uptake and being extended upwards into the chimney or funnel.
Figures 6, 7 and 8 are respectively side and end elevations and plan of a double
ended boiler showing the air pipes A A' traversing the uptake and passing up and
terminating in the funnel. In this example service pipes D D supply air to the
coils A Aat each end.
Figures 9 and 10 are a part elevation and plan of a brick chimney from a
boiler furnace and showing two sets of air pipes. A. A' fitted therein.
In each case the air supplied by the service pipes D from a compressor or
receiver is under pressure and is heated by the waste fire gases in its passage
through the coils A A¹ from which it is discharged through orifices or jets formed
in or on the coils the discharge being, upwards into the chimney so as to create or
induce draught.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is
As means for inducing draught in boiler or other furnaces pipes or coils fitted in
the uptake or chimney and having orifices or jets for the discharge of heated air
under pressure substantially as described.
Dated this Twenty-fifth day of May 1892.
CRUIKSHANK & FAIRWEATHER,
62, St. Vincent Street, Glasgow, Agents.