IMPROVEMENTS IN APPARATUS FOR REGULATING THE SUPPLY OF AIR TO FURNACES "
Year: 1883

page_text: LETTERS PATENT to William Charles Gale of 8 Myrtle Villas Vant Road
Lower Tooting in the County of Surrey for an Invention of "IMPROVEMENTS
IN APPARATUS FOR REGULATING THE SUPPLY OF AIR TO FURNACES
"
PROVISIONAL SPECIFICATION left by the said William Charles Gale at
the Office of the Commissioners of Patents on the 31st December 1883.
WILLIAM CHARLES GALE of 8 Myrtle Villas Vant Road Lower Tooting in the
County of Surrey "IMPROVEMENTS IN APPARATUS FOR REGULATING THE SUPPLY
OF AIR TO FURNACES
"
This invention has for its object improvements in apparatus for regulating the
supply of air to furnaces.
For regulating the supply of air to furnaces I provide the furnace door with a
chamber at the back to which air can be admitted through gratings or openings at
the upper part of its sides and front. Inside the chamber and just below these air
openings is a hinged flap or door by which the entrance of air into the chamber can
be shut off or opened. Below the flap is a cylindrical vessel containing mercury.
The flap is coupled by a connecting rod with a piston rod that works through the
cover of the cylinder. Inside the cylinder the piston rod has fixed to it a hollow
vessel or float which fits loosely in the cylinder like a piston-a slight space only
being left between its sides and the sides of the cylinder. Through the bottom of
the hollow vessel or float is a hole fitted with a valve opening downwards which
allows mercury to pass out from the vessel or float whenever the vessel or float is
raised but does not permit mercury to enter.
At
Through the furnace door are formed a number of slots by which air can
pass to the furnace from the chamber. At the back of the door and inside
the chamber are a number of slotted baffle plates set one behind the other―
the slots in the plates are not in a line with one another so that the air
passing to the furnace from the chamber has to pass in a zig-zag course.
one side of the chamber and on one end of the axis of the hinged flap which
controls the admission of air is a lever arm. Its own weight tends to turn it
downwards and to close the flap. On the same side of the chamber is a lever arm
weighted at the top and turning on a pin joint near its lower end.
The weight
[Price 6d1

page_text: tends to turn the upper arm forwards the lower arm rests against a pin which
projects from a horizontal slide carried below the chamber.
When the furnace door is shut the end of the slide strikes against the front of
the furnace and is thereby moved back bringing the upper arm nearly vertical and
into such a position that the flap valve at the top of the chamber can close.
When the furnace door is opened the weighted arm falls forward and striking
against the arm on the axis of the flap valve opens this valve at the same time
raising the float in the mercury and allowing the mercury previously contained in
the float to flow out from it.
So soon as the door is closed and the weighted arm no longer holds the flap valve
open the weight of the arm tends to depress the float into the mercury and the
flap valve gradually closes as a small hole is provided in the bottom of the float to
allow mercury to pass inwards into it.
It will be seen that by this construction the mercury and flap valve are both
enclosed in a chamber at the back of the furnace door where they are out of
danger and kept clean whilst at the same time the baffle plates at the front of the
chamber prevent radiation of heat from the furnace door so that there is no risk of
the mercury getting over-heated.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Charles Gale in the Patent Office on the 30th June
1884.
WILLIAM CHARLES GALE of 8 Myrtle Villas Vant Road Lower Tooting in the
County of Surrey. "IMPROVEMENTS IN APPARATUS FOR REGULATING THE SUPPLY
OF AIR TO FURNACES
"
This Invention has for its object improvements in apparatus for regulating the
supply of air to furnaces.
For regulating the supply of air to furnaces I provide the furnace door with a
chamber at the back to which air can be admitted through gratings or openings
at the upper part of its sides and front. Inside the chamber and just below these
air openings is a hinged flap or door by which the entrance of air into the chamber
can be shut off or opened. Below the flap is a cylindrical vessel containing
mercury. The flap is coupled by a connecting rod with a piston rod that works
through the cover of the cylinder. Inside the cylinder the piston rod has fixed to
it a hollow vessel or float which fits loosely in the cylinder like a piston—a slight
space only being left between its sides and the sides of the cylinder. Through the
bottom of the bollow vessel or float is a hole fitted with a valve opening downwards
―which allows mercury to pass out from the vessel or float whenever the vessel
or float is raised but does not permit mercury to enter.
course.
Through the furnace door are formed a number of slots by which air can pass to
the furnace from the chamber. At the back of the door and inside the chamber
are a number of baffle plates set one behind the other. If the baffle plates are
slotted the slots in the plates are made so as to be out of line with one another so
that the air passing to the furnace from the chamber shall have to pass in a zig-zag
At one side of the chamber and on one end of the axis of the hinged flap
which controls the admission of air is a lever arm. Its own weight tends to turn
it downwards and to close the flap. On the same side of the chamber is a lever
arm weighted at the top and turning on a pin joint near its lower end. The weight
tends to turn the upper arm forwards the lower arm rests against a pin which
projects from a horizontal slide carried below the chamber.
When the furnace door is shut the end of the slide strikes against the front of
the furnace and is thereby moved back bringing the upper arm nearly vertical and
into such a position that the flap valve at the top of the chamber can close.
When the furnace door is opened the weighted arm falls forward and striking
against the arm on the axis of the flap valve opens this valve at the same time
raising the float in the mercury and allowing the mercury previously contained in
the float to flow out from it.
So soon as the door is closed and the weighted arm no longer holds the flap valve
open the weight of the arm tends to depress the float into the mercury and the flap
valve gradually closes as a small hole is provided in the bottom of the float to allow
mercury to pass inwards into it.
It will be seen that by this construction the mercury and flap valve are both
enclosed in a chamber at the back of the furnace door where they are out of danger
and kept clean-whilst at the same time the baffle plates at the front of the
chamber prevent radiation of heat from the furnace door so that there is no risk of
the mercury getting overheated.
In the Drawings hereunto annexed I have shewn apparatus arranged in the
manner I prefer for carrying out my Invention.

page_text: Figure 1 is a front view, Figure a plan view; Figure 3 a side elevation and
Figure 4 a vertical cross section of the apparatus. Figure 5 is a vertical section on
a larger scale of the mercury vessel and float contained therein-Figure 6 shews a
modified construction of the apparatus.
A is the furnace door formed as is usual with hinge pieces A¹ at one end and
with a latch A2 at the opposite end-A³ is a series of slots or openings formed
through the door by which air can enter the furnace.-B is a guard plate also
carried as is usual on the inside of the door-C is the chamber bolted to the
outside of the door-C¹ are air inlet openings at the sides and front of the upper
part of this chamber-D is the flap carried on pins or pivots D¹ which pass through
holes in the ends of the chamber-E is the vessel containing mercury it is bolted
to the inside of the chamber as shewn-F is the rod which works through the
cover of this vessel and which at its lower end is coupled to the float G. The way
in which I connect it to the float is best seen in Figure 5.-At its lower end is a
valve face F and extending below this valve face is a reduced portion which passes
through a hole in the bottom of the float and below the float has a nut F² screwed
on to it. Through the bottom of the float are also holes G which are covered by
the valve-When the rod F is lifted the valve F¹ moves away from the holes in the
float and the nut F' raises the float and allows the mercury within it to flow out
through the holes G³-When the rod is depressed the valve F1 again closes the
holes and mercury can then only enter the float slowly through the small
hole G (see Figure 5)-F3 is a link by which the upper end of the rod F is
connected to the flap D-D2 is an arm fixed to one of the pivots of the flap D
outside the casing.-H is a weighted lever arm turning on a pin H¹. It tends
always to fall against the arm D2 and turn it into the position shewn in Figure 3
and thereby raise the flap D and float G into the position shewn in Figure 4.-The
lower arm of the lever H rests against a pin K¹ carried by a slide K-Whenever
the furnace door is opened the weighted arm H drops against the arm D² and raises
the flap, and as the door is again closed the end of the slide K comes against the
furnace front and is thereby pressed back and the pin K' upon it made to turn the
arm H away from the arm D2-The flap and arm will then tend to descend by
their own weight but the speed at which they can descend will be controlled
by the rate at which mercury can enter the float through the small hole G³—
L.L' are two baffle plates fixed inside the chamber C in front of the mercury
vessel E. The one nearest to this vessel descends from the top of the chamber and
a space is left between its lower edge and the bottom of the chamber whilst the
other plate rises from the bottom of the chamber and a space is left between its
upper edge and the top of the chamber so that air entering the chamber C
through the openings C¹ has to pass in a zig-zag course before it enters the furnace.
Or as before stated a number of slotted baffle plates one in front of the other might
be used and the slots in one be set out of line with the slots in the plates before
and behind it to effect the same object.
In this way direct radiation of heat from the furnace to the mercury vessel E is
prevented and the vessel is kept cool by reason of all of the air which enters the
furnace through the door having to travel past it.
In the modification of the apparatus shown in Figure 6 the arm H is drawn
forwards by a chain which passes over a small pulley M and has a weight N
attached to it in place of the weight being rigidly secured to the arm as shewn in
Figure 3.
Having thus described the nature of my invention and the manner of performing
the same I would have it understood that I am aware that it has before been
proposed to control the admission of air to a furnace through the furnace door by
means of a flap or series of flaps which close the air inlets as they turn downwards
and also that it has been proposed to control the descent of the flap or flaps by the
slow-admission of mercury into a float to which the flap or flaps are connected I
do not therefore make any general claim to the use of such flaps and mercury

page_text: control vessel.-Heretofore however the mercury vessel has either been carried by
the front of the furnace or has been fixed in front of the furnace and in either
position is exposed to dust and otherwise liable to injuries which interfere with its
proper working
What I claim is :-
First-The construction of apparatus for regulating the supply of air to furnaces
substantially in the manner hereinbefore described.
Second-The employment of a bath of mercury placed inside of a chamber fixed
on the outer side of the door of a furnace for controlling the admission of air to
the chamber substantially as described.
In witness whereof I the said William Charles Gale have hereunto set my
hand and seal this thirtieth day of June in the year of our Lord One thousand
eight hundred and eighty four.