Year: 1887

page_text: [Communicated from abroad by HUGH KENNEDY, of Sharpsburg, in the County of
Allegheny and State of Pennsylvania, United States of America, Engineer.]
I JOHN THOMSON KING of 4 Clayton Square Liverpool in the county of Lancaster,
Patent Agent, 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 :-
Great difficulty and serious loss have been experienced in the use of the valves
which control the gas flues of hot blast stoves. The gas flue leads from the top of
the furnace to the combustion chamber of the stove and the valve is arranged in it
near the stove. Owing to the intense heat to which this valve and its seat are
exposed, they are liable to burn out, and to prevent this, it has been customary to
water cool them. These stoves are generally of a reversing character, that is there
are several of them and the gas is caused to pass out through each of them for a
time to heat it up and then the gas is shut off and the air blast is permitted to pass
through the heated stove until the heat therein is reduced. When the air is thus
passing through the stove, the gas valve is closed, but if the valve should be warped,
or for any other reason should not be tightly closed, the air being under pressure will
find its way past the valve and burn in the flue, creating such a heat as to seriously
injure and often destroy the valve and sometimes burn out the flue. Difficulty and
danger are also experienced even when the stove is not "on air" by the gas leaking
into it through a leaky valve and collecting in quantity, so that when the workmen
enter the stove to clean it, they are sometimes suffocated and at other times having a
ID071

page_text: light with them are the victims of an explosion of the gas. This latter contingency
is liable to occur in boiler furnaces where gas is used as fuel in case the gas should
leak into the fire box and fill it. Then, if a man should enter the fire box or ashpit
to make repairs, he is liable to be suffocated or to cause an explosion. Such explosions
sometimes occur when the fireman goes to light up his furnace in the ordinary way.
One of the objects of my invention is to obviate the possibility of such accidents and
damage by reason of the leakage of the gas at the valve, and this I accomplish by a
construction that enables me to break the connection between the gas main and the
stove or furnace.
Great difficulty has also been experienced in the use of the valves which control the
stack flue of hot blast stoves. When a stove is "on Gas" the heated gases passing
over the valve on their way to the stack, heat the valve and the stack flue up to a
very high temperature; so that it is necessary, in order to preserve the valve and its
seat, to provide them with water cooling devices; but this provision does not prevent
the valve and its seat from becoming warped by the great extremes of temperature
through which the various changes in the currents of the stove cause them to pass.
The result is that the valve is seldom tight, and the leakage is constantly increasing
as the period of its use lengthens. A very serious evil arising from this leakage is
experienced when the stove is on air, because the pressure of the blast forces the air
through the leaky valve into the stack flue and destroys or injuriously affects the
draft in the other stoves which are connected with the same stack. There are always
several stoves connected with a single stack, and as the air is under pressure, and the
wasted gases are not, the draft through the leaky valve is sufficient in many instances
to make a serious defect in the operations of the stoves which are
on gas" and
connected with the same stack. My invention is designed to obviate these difficulties,
and its principal advantages are that it enables me to dispense with a stack flue valve,
and completely prevents any interfereance by the stoves on air with the stoves on gas.
I will now describe my invention so as to enable others to make and use the same,
reference being had to the accompanying drawing, in which figure 1. is a sectional
view indicating a simple form of my improved gas connection; figures 2 and 3 are
like views of modifications of the same; figure 4 is a vertical sectional view illus-
trating a simple form of my improved stack connection; figure 5 is a vertical
sectional view of my improvement as applied to the existing stove; and figure 6 is a
side elevation of a portion of the stove and of the stack flue.
"
In the drawing a indicates the side of the hot blast stove b the gas flue, c the pipe
leading from the gas flue to the stove, and d the valve which controls the gas flue.
The pipe c stops short of the stove, and opposite its end there is an opening e.
Mounted on the pipe c is a sliding section or connecting pipe f, which may be moved
back and forth on the pipe c and into the opening e by handles g.
The operation of this device is as follows:-When it is desired to admit gas to the
stove a the movable section f is pushed forward on the pipe c until it enters the
opening e. Then the valve d is opened and the gas is permitted to pass into the stove.
When it is desired to stop the flow of gas for any reason, such as when the stove is
reversed, the opening e is closed by a sliding or other suitable door h. It is apparent
that when this is done, after the movable section f is pulled back from the opening,
there is no possible access of gas to the stove from the pipe c, and that it is impossible
for the air then passing through the stove to gain access to the gas flue b. Thus
the chief cause of danger to the valve d and flue is taken away, and the durability
of these parts is increased enormously. Perfect safety is insured against the explosions
by gas leaking from the flue b into the stove. The point where the gas passes from
the gas flue into the combustion chamber of the stove or boiler furnace is extremely
hot and is liable to burn off the end of the section f in a short time; and in order
to prevent this I make the hole e of larger diameter than the pipe f so that a current
of air enters the stove on all sides of the pipe and thereby protects it from burning
out as well as affording a supply of air for the combustion of the gas in the combustion
chamber of the stove.

page_text: In figure 2. the connecting pipe fis entirely free from the gas pipe c, one end
resting upon a suitable support on the side of the stove, and the other upon the
valve case or other suitable supporting part of the gas supply apparatus.
In figure 3 the connecting pipe is shown as hinged to the valve case, or to the
pipe c above the valve case, in such a manner that it will swing into and out of
the opening e in the stove.
These same devices are applicable without material change to the fire boxes of
boiler and other furnaces using gas as fuel, as will be understood by the skilled
mechanic, the wall a answering to indicate also the side or front of such firebox.
The Stack flue connections consist in devices similar in some parts to those just
described. In the side of the stove a is an opening, k which is connected with the
stack flue by the pipe m. This opening k is faced with a suitable casting n which
may have a ground seat n', for receiving the beveled end of the pipe m.
The pipe m
is composed of a fixed or stationary section m³, and a moving or telescopic section m³
which is capable of being moved back and forth in the fixed section m¹ by means of
handles m³ so as to connect and disconnect the pipe me with the opening k. The stove
is provided with a sliding door or lid o for closing the opening when the pipe m is
disconnected therefrom and this door o when the pipe m is connected with the opening
may be fastened out of the way by means of the hook p engaging with the staple p
or if desired the door may slide laterally or be entirely removable. This, however is
an immaterial matter of construction as any form of device may be employed which
will tighly close the opening k when the stove is on air and the pipe m is disconnected.
When the pipe m is connected with the stove, it may be fastened by means of straps 9;
hinged to the side of the stove, and engaging with lugs r, to which they are secured
by keys passing through the straps and bearing against the lugs, as shown by the
broken lines in figure 5 and by full lines in figure 6. When the pipe m is disconnected,
the end of the section m may be closed by a suitable cap s, which is secured thereto
by straps t and keys u, the purpose of which is to prevent a current of cold air from
being drawn into the stack flue through the open end of the pipe m. Any other
suitable device for closing the end of the pipe when disconnected from the stove may
be used; as, for instance, in figures 5 and 6 I show the application of my improvement
to a stove already fitted with a valve v. As ordinarily constructed the presence of
this valve does no harm. It acts as well to close the pipe m when disconnected from
the stove as any other form of cap, and being there, it is not necessary to remove it.
Thus constructed the operation is as follows:-When a stove is
on gas" the
pipe m is connected with the opening k, as shown in figure 5 of the drawing, and the
gas passes through the opening k and pipe m to the stack flue in the usual way.
When it is desired to reverse the stove, the fastening devices are unloosed, the
telescoping end of the pipe m is drawn back so as to completly disconnect it from
the stove, the door o is lowered so as to close the opening k, and the pipe m is closed
by means of the cap s, valve t, or other suitable closing device. It is apparent that
there is no danger of the air from the stove blowing into stack flue when the pipe m
is disconnected and the opening k closed; and if the opening k does leak by reason
of the door o not fitting closely, no harm is done, except that a small portion of the
blast is wasted. It is also apparent that as the air (the blast) can not obtain access to
the pipe m no valve is necessary, and that any suitable device for closing the pipe m
will answer in lieu thereof.
"
Thus I am enabled to take away one of the most fruitful causes of irregularity in
the action of these stoves, and to dispense with one of the most troublesome and
expensive features in connection therewith.
I do not desire to limit any part of my invention to the exact construction of
devices employed, as for instance the connecting pipes may be connected by a hinge,
a slide, or other means which would suggest itself to the skilled mechanic; nor do I
desire to limit any part of my invention to hot blast stoves but desire to include other
combustion chambers having valves and connections between the gas supply and the
combustion chamber or between the combustion chamber and the stack.

page_text: Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed, I declare that what I claim is:
1. The combination of a hot blast stove or other combustion chamber, with a gas
flue having a gas valve, and a pipe section connecting the gas flue with the stove,
said pipe section being detachable, substantially as and for the purpose specified.
2. The combination of a hot blast stove or other combustion chamber, with a gas
flue having a gas valve, and a pipe section connecting the gas section with the stove,
said pipe section being detachable from the stove and independent of the gas valve ;
substantially as and for the purpose specified.
3. The combination of a hot blast stove or other combustion chamber, with a stack
flue an intermediate connection pipe capable of being detached from the stove or flue,
substantially as and for the purpose described.