IMPROVEMENTS IN STEAM BOILER AND OTHER PROVISIONAL SPECIFICATION
Year: 1883

page_text: LETTERS PATENT to Peter William Willans of Thames Ditton in the County
of Surrey for an Invention of "IMPROVEMENTS IN STEAM BOILER AND OTHER
PROVISIONAL SPECIFICATION left by the said Peter William Willans at
the Office of the Commissioners of Patents on the 23rd February 1883.
PETER WILLIAM WILLANS of Thames Ditton in the County of Surrey:
"IMPROVEMENTS IN STEAM BOILER AND OTHER FURNACES
"
This Invention has for its object to prevent the exit of gases from the fire door
of a steam boiler or other furnace when air is supplied under the bars by a fan or
other mechanical contrivance and at the same time to avoid the trouble and
inconvenience of a closed stokehold.
For this purpose I take the air from the fan into a closed chamber which covers
both the opening into the space below the bars and the ordinary fire door. I
obtain access to the fire door by opening a door in this chamber through which
door the main bulk of the air from the fan escapes when it is desired to put coals
on the fire.
The large door in the air chamber is thus opened first and then the ordinary fire
door, or it may be arranged in such a manner that the two doors are both opened
at the same time.
It will be seen that this arrangement renders it impossible for the gases in the
furnace to escape through chinks in the fire door when closed, or through the fire
door itself when open. It also makes unnecessary any mechanical arrangement for
stopping the fan when coal has to be put on.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Peter William Willans in the Great Seal Patent Office on the
22nd August 1883.
PETER WILLIAM WILLANS of Thames Ditton in the County of Surrey
"IMPROVEMENTS IN STEAM BOILER AND OTHER FURNACES
"
The object of this invention is to prevent the exit of gases from the fire door of
a steam boiler or other furnace when air is supplied under the bars by a fan or
other mechanical contrivance and at the same time to avoid the trouble and
inconvenience of a closed stoke hole.
For this purpose I take the air from the fan into a closed chamber which covers
both the opening into the space below the bars and the ordinary fire door.
I obtain access to the fire door by opening a door in this chamber through which
door the main bulk of the air from the fan escapes when it is desired to open the
fire door to stoke or rake over the fire.
The large door in the air chamber is thus opened first and then the ordinary fire
door or it may be arranged in such a manner that the two doors are both opened
by the same operation.
It will be seen that this arrangement renders it impossible for the gases in the
furnace to escape through chinks in the fire door when closed or through the fire
door itself when open. "It also makes unnecessary any mechanical arrangement for
stopping the fan when coal has to be put on.
The drawings annexed shew examples of steam boiler furnaces fitted with an air
chamber in front of the fire door and ash pit as above described.
Figure 1 is a sectional elevation of a return tube boiler and Figure 2 a front end
view with part of the air casing removed to shew the fire door. In these figures
A is the shell of the boiler, B the fire box, C the combustion chamber, D. D. the
tubes, E the smoke box or up take, F the fire bars.
G is the air chamber arranged to cover the fire door and the opening in front of
the ash pit.
Air is supplied under pressure to the chamber by a fan through the
air passage or pipe g. In the front of the chamber is a door f (hinged on the
pin f) and secured when closed by any ordinary catch-through this door access
is obtained to the fire door e and ash pit. The door f is connected as shewn by a
link d to the fire door e. When the door f is closed the link & holds the fire door e
closed also. On opening the door f the fire door at first remains closed as the
link d is at first merely turned on the pin at its upper end and the fire door only
commences to open when the door f has been opened to such an extent as to draw
downwards the link d. In this way the pressure of air is reduced in the furnace
before the fire door is opened without stopping the fan by which the air is supplied.
When the door f is fully opened free access can be had to the fire to break it up
and to recoal and in order to prevent too strong a current of air escaping at this
time from the front of the air chamber a tail piece on the door is then made to
partially close the air passage g as shown.
It will be seen that this arrangement renders it impossible for the gases in the
furnace to escape through chinks in the fire door when closed as they would do if
air under pressure were only admitted to the ash pit. It also makes unnecessary
any mechanical arrangement for stopping the fan when the fire door has to be
opened.
Figure 3 shows another arrangement in which the air chamber is closed by a
loose door a which when in place is secured by catches. When this door is removed
the fire door b may be opened-this door is hinged on the pin c and is so formed

page_text: that when open a plate attached to or formed with it almost covers the ash pit
opening thus preventing a free flow of air to the furnace and so preventing the
ignited gases in the furnace from being blown out from the fire door opening when
the door is opened.
The air passage g may be arranged as shown by the full lines or as shewn in
dotted lines or in other convenient manner.
Figure 4 shews a boiler of the locomotive type. In this figure the air chamber
is closed as in Figure 3 by a loose door a or it may be a hinged door.
The opening at the front of the ash pit is shewn to be provided with a hanging
door or flap which gives way to allow air under pressure to pass from the air
chamber into the ash pit and so to the furnace but when the door a is opened and
the pressure in the air chamber so reduced the flap closes and prevents any air
pressure under the bars which might be caused by the momentum and direction of
the current of air. The fire door b may then be opened for firing.
In Figures 3 and 4 similar parts are marked with similar letters to Figures 1
and 2.
Having thus described the nature of my invention and the manner of performing
the same I would have it understood that I claim :-
First The construction of the furnaces of steam boilers and other furnaces with
a closed chamber covering both the fire door and opening into the space below the
fire bars, this closed chamber having a door in it to relieve the pressure of air under
the bars and to give access to the fire door and ash pit substantially as described.
Second-The combination of the enclosed air chamber G with its door f linked
to the fire door substantially as described so that when the door of the chamber
has been partially opened the other door is caused to open also substantially as
described.
Third-The combined arrangements of apparatus applied to the front of furnaces
substantially as described.
In witness whereof I the said Peter William Willans have hereunto set my
hand and seal this 20th day of August in the year of our Lord One thousand eight
hundred and eighty three."
TTTT ITTA
ANS (L.S.)