Improvements in Force Draught Apparatus for Steam Boiler and other Furnaces.
Year: 1886

page_text: Date of Application, 27th Aug., 1886.
Complete Left, 25th June, 1887.
Complete Accepted, 26th July, 1887.
RESERVE
BOLALIVA.
Improvements in Force Draught Apparatus for Steam Boiler
and other Furnaces.
I JOHN WILLIAM HOLDEN of 54 Portland Street, Manchester, in the County of
Lancaster, Engineer, do hereby declare the nature of my invention to be as follows:-
This invention refers to improvements upon an invention for which Letters Patent
No. 1460, were granted to me and dated the 3rd day of February 1885, and has for
its object a novel means of keeping the fire-bars cool, of heating the air to the steam
jet and of obviating the noise arising from the great inrush of air when the steam jet
is in action.
In performing my present invention I extend the ash pit slightly beyond the bridge
in order to form an inlet at the far end of the extended ash pit for the admission of
air to a pipe which by preference is extended along the bottom of the ash pit to the
dead plate through which it passes upwards to my improved steam and air jet which
is located as heretoforo above the fire-door.
In this manner and by compelling the large quantity of air which is required to
support the steam and air jet to pass beneath the fire bars, such fire bars are kept cool.
The air supply through the fire bars to the furnace itself is also improved by this
arrangement whilst the air itself, in passing through the said pipe is heated to the
ignition point, the temperature being however regulated by additional adjustable inlets
located in such pipe near the dead plate and at the same time by so arranging the
inlet to such pipe as aforesaid 1 secure the desired freedom from noise arising from
the great inrush of air.
Where compressed air is available it may be used in place of steam for creating the
vacuum with this my improved apparatus.

page_text: and other Furnaces.
I JOHN WILLIAM HOLDEN of 54 Portland Street, Manchester, in the County of
Lancaster, Engineer, 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 statement:—
This invention refers to improvements upon an invention for which Letters Patent
No. 1460, were granted to me and dated the 3rd day of February 1885, and has for
its object a novel means of keeping the fire bars cool, of heating the air to the
steam jet and of obviating the noise arising from the great inrush of air when
the steam jet is in action.
In performing my present invention I extend the ash pit slightly beyond the bridge
in order to form an inlet at the far end of the extended ash pit for the admission of
the air through the hollow fire bars to the hollow dead plate through which it passes
upwards to my improved steam and air jet which is located as heretofore above the
fire door.
On the accompanying drawing Fig. 1. is a front view, Fig. 2. a side sectional view
and Fig. 3. a sectional plan of a steam boiler furnace with my improvements applied
thereto.
In all the views a. is the modified bridge forming an extended ash-pit as illustrated
and so arranged as to form inlets b. b. for the admission of air through the hollow
fire bars c. c. to the hollow dead plate d.
Rising from this dead plate are by preference a pair of pipes e. e. (seen more clearly
in Fig. 1.) terminating at their upper extremities in a pair of my improved
steam jets ff. the subject of Letters Patent No. 1460 A.D. 1885.
In this manner and by compelling the large quantity of air which is required to
support the steam and air jet f.f. to pass through the fire bars c. c. as indicated by the
arrows in Fig. 2., such fire bars are kept cool.
The air supply between the fire bars to the furnace itself is also considerably
augmented by this arrangement whilst the air itself in passing through the fire bars
to the steam jets is heated almost to the ignition point.
The temperature can however be regulated if necessary by additional adjustable
inlets located in such hollow fire bars near the dead plate. I also find that by so
arranging the inlet to such hollow fire bars as aforesaid secure the desired freedom
from noise arising from the great inrush of air.
Where compressed air is available it may be used in place of steam for creating the
vacuum with this my improved apparatus.
In my Provisional Specification I mentioned a pipe extended by preference along
the bottom of the ashpit as a means of communication for conveying the air between
the extended ash pit and the dead plate but I find in practise that a better result is

page_text: obtained by making the fire bars hollow so as to form in themselves the media of
communication as aforesaid.
Although only shewn as applied to an ordinary steam boiler furnace it will be
apparent that the improvements are equally applicable to other classes of furnaces.
Having thus 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 :-
1st. The improvements in forced draught apparatus for steam boiler and other
furnaces substantially as and for the purposes herein before described and illustrated
on the accompanying drawing.
2nd. The improved construction and arrangement of bridge forming an extended
ash pit and the inlet to the hollow fire bars and the employment of such hollow
fire bars or their equivalents for conveying the air to the dead plate and thence to the
steam jet whereby the same becomes highly heated, substantially as and for the
purposes hereinbefore described and illustrated on the accompanying drawing.
Dated the oul
T1007
JOHN G. WILSON,
Agent for the Applicant.