Improvements in or connected with Blast Furnaces for Facilitating the Tapping thereof.
Year: 1893

page_text: Date of Application, 13th Oct., 1893
Complete Specification Left, 13th July, 1894-Accepted, 1st Sept., 1891
PROVISIONAL SPECIFICATION.
Improvements in or connected with Blast Furnaces for Facilitating
the Tapping thereof.
I, DAVID BAKER, of The Maryland Steel Company, Sparrow's Point, Maryland,
United States of America, Superintendent, do hereby declare the nature of this
invention to be as follows:-
This invention relates to improvements in or connected with blast furnaces and
is designed to provide convenient means for opening the tap hole when the furnace
is to be discharged. In ordinary practice the tap hole is commonly closed by a
plug of clay which in the working of the furnace becomes burnt in and requires the
use of very considerable force to dislodge it, whilst by reason of the heat and
other causes it is practically impossible for the workmen to approach sufficiently
near the furnace to do this easily, and the dislodging of the plug is generally
effected by means of a bar or tool of from 15 to 25 feet in length, and which is very
awkward to handle.
To obviate this difficulty 1 provide in proximity to the tap hole a drill adapted
to be operated by motive fluid or other power and so arranged that the drill can
be directed with adequate precision on the plug of the tap hole.
For this purpose the drill is mounted on a frame which is adjustably connected
to or suspended from a movable or swinging bracket or support and is provided at
its forward end with a cross bar or equivalent means adjustable as to height and
adapted to detachably secure the frame in operative position, it may be between
two side supports or pillars to one of which the said bracket or support is or may
be connected.
For this purpose the said cross bar may be provided at one end with a fork adapted
to fit a rod or bar carried by a vertical support or pillar, and adapted at the other
end to be connected by a pin or equivalent device with the projecting portion of an
eye fitted on another rod or bar carried by a second vertical support or pillar
arranged opposite to the first, the tap hole being between the two.
In one arrangement, one or more of the arms or members of the swinging
bracket or support is or are made tubular so that motive fluid can be conveyed
through the same from a fixed supply pipe, and thence to the drill, by means of a
flexible pipe or hose the motive fluid being distributed by suitable pipes and
cocks to the ends of a feed cylinder with the piston rod of which the drill is
connected for the purpose of moving or feeding it in guides on the said frame.
In another arrangement the motive fluid is conveyed from a fixed supply pipe to
the feed and drill cylinders through telescopic pipes connected by ball and socket
or equivalent connections to pipe attachments secured to the fixed pipe and to the
distributing pipes on the frame. In each case the aforesaid piston rod may be
made hollow so as to serve to convey motive fluid from the feed cylinder to the
valve chest of the cylinder of the drill proper and by means of which the drill is
operated.
In a convenient form of drill and accessories for the purpose of my present
invention, the main or percussion-cylinder of the drill, which may be of the Rand,
Ingersol, or any other suitable type, is arranged to slide along the aforesaid frame
and the frame itself is adapted to turn vertically on the aforesaid cross bar. The
weight of the frame with the drill and its attachments is or may be counterbalanced
by weights and chains or in any other suitable manner, so that the frame may be
more readily moved into or out of operative position. To the rear end of the drill
there is connected the aforesaid piston-rod of the feed cylinder, which forms also a

page_text: pipe for admitting motive fluid to the percussion-cylinder. The two ends of the
interior of the feed-cylinder are connected by a pipe which is joined by a three-way
cock to an exhaust pipe, which may lead simply into the outer atmosphere or into
a condenser. The first-mentioned pipe is arranged to be supplied with the motive
fluid between the aforesaid three-way cock and the front end of the feed-cylinder.
The arrangement is such that when motive fluid is admitted to both ends of the
feed-cylinder, the drill will be fed forward on account of the difference of pressure
on the two sides of the piston of the said cylinder and that when the rear end of
the cylinder is placed in communication with the exhaust pipe, by means of the
three-way cock the piston of the feed-cylinder and the drill will be forced back.
Between the feed-cylinder and the percussion-cylinder, a clamp is arranged by
means of which any desired amount of friction can be put on the aforesaid piston-
rod, so as to control the rate of feed.
Means are or may be provided for partially rotating the drill spindle at each
stroke and for operating from a distance the valves for controlling the flow of fluid
to one end or the other of the cylinder.
Improvements in or connected with Blast Furnaces for Facilitating
the Tapping thereof.
I, DAVID BAKER, of The Maryland Steel Company, Sparrow's Point, Maryland,
United States of America, Superintendent Blast Furnace Department, 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 :-
it
This invention relates to improvements in or connected with blast furnaces and
is designed to provide convenient means for opening the tap hole when the furnace
is to be discharged. In ordinary practice the tap hole is commonly closed by
plug of clay which in the working of the furnace becomes burnt in, and requires
the use of very considerable force to dislodge it, whilst by reason of the heat and
other causes, it is practically impossible for the workmen to approach sufficiently
near the furnace to do this easily, and the dislodging of the plug is generally
effected by means of a bar or tool of from 15 to 25 feet in length, and which is
very awkward to handle.
To obviate this difficulty I provide in proximity to the tap-hole a drill adapted
to be operated by motive fluid or other power and so arranged that the drill can be
directed with adequate precision on the plug of the tap-hole.
For this purpose the drill is mounted on a frame which is adjustably connected
to or suspended from a movable or swinging bracket or support and is provided at
its forward end with a cross bar or equivalent means adjustable as to height and
adapted to detachably secure the frame in operative position, it may be between
two side supports or pillars to one of which the said bracket or support is or may
be connected.
For this purpose the said cross bar may be provided at one end with a fork
adapted to fit a rod or bar carried by a vertical support or pillar, and adapted at
the other end to be connected by a pin or equivalent device with the projecting
portion of an eye fitted on another rod or bar carried by a second vertical
support or pillar arranged opposite to the first, the tap hole being between
the two.

page_text: In one arrangement, one or more of the arms or members of the swinging bracket
or support is or are made tubular so that motive fluid can be conveyed through the
same from a fixed supply pipe, and thence to the drill, by means of a flexible pipe
or hose, the motive fluid being distributed by suitable pipes and cocks to the ends
of a feed cylinder with the piston rod of which the drill is connected for the purpose
of moving or feeding it in guides on the said frame.
In another arrangement the motive fluid is conveyed from a fixed supply pipe to
the feed and drill cylinders through telescopic pipes connected by ball and socket
or equivalent connections to pipe attachments secured to the fixed pipe and to the
distributing pipes on the frame. In each case the aforesaid piston rod may be made
hollow so as to serve to convey motive fluid from the feed cylinder to the valve
chest of the cylinder of the drill by means of which the percussive action of the
drill is produced, and which will hereinafter be referred to as the percussion-
cylinder.
Means are or may be provided for partially rotating the drill spindle at each
stroke, and for operating from a distance the valves for controlling the flow of fluid
to one end or the other of the cylinder.
In the accompanying illustrative drawings.
Figs. 1 & 2 show respectively a sectional side elevation and a sectional plan of a
portion of a blast-furnace provided with drilling-apparatus according to my
invention, the drilling-apparatus being represented in these figs. in its operative
position.
Fig. 3 is a horizontal section, to a larger scale, showing a portion of the apparatus,
the section being taken through the axis of the feed-cylinder; and
Fig. 4 is a cross-section on the line y y of Fig. 3;
Fig. 5 is an end elevation showing a modified construction of my drilling-
apparatus.
1 is a part of the lower portion of a blast-furnace and 2 is the tap-hole therein
represented as plugged. 3 is the percussion cylinder of the drill which may be of
the Raud, Ingersol, or any other suitable type, and is mounted on a frame 4 so as
to be movable lengthwise thereon between grooved guide-plates 5. The frame 4 is
suspended by means of brackets 6, from a cross-bar 7 which is provided at one end
with a fork 8 adapted to fit a fixed vertical bar 9 and at its other end is adapted to
be detachably secured by a bolt 10 and a pin 11 to a projecting portion or lug 12 of
a vertically adjustable eye 13 threaded on another fixed vertical bar 14.
bars 8 and 14 are secured by brackets 15 to two vertical pillars 16 and 17 respectively
arranged on opposite sides of the tap-hole 2.
The
The frame 4 is adjustably suspended, by means of a chain 18, from a bracket 19,
which is secured to the pillar 16 by means of brackets 20 in which it is adapted
to swing laterally. To the frame 4 there is also secured the feed cylinder 21, the
piston rod 22 of which is attached by means of a flange 23 (Fig. 3) to the rear
end of the percussion cylinder 3. The piston rod 22 is tubular and extends
completely through the piston 24, terminating at the rear end surface of the said
piston. The feed-cylinder 21 may advantageously be provided with a coating 25
of material, such as asbestos, that is a bad conductor of heat. The two ends of
the interior of the cylinder 21 are connected by a pipe 26 to which is joined by a
three-way cock 27, an exhaust-pipe 28, which may lead, according to desire and to
the motive fluid employed. either to a condenser or simply into the external
atmosphere. The motive fluid is conducted to the pipe 26 by a pipe 28 which is
joined to the portion of the pipe 26 that connects the cock 27 to the front end of
the interior of the cylinder 21. In the construction shown in Figs. 1 to 4, the
pipe 29 is connected with the fluid-supply pipe 30 through a flexible pipe 31 and
the portions 19" and 19 of the bracket 19, which in this case are made tubular.
In the modified construction shewn in Fig. 5 the pipe 29 is connected with the
fluid-supply pipe 30 by means of telescopic pipes 32, 32ª and 32° and ball-and-socket
joints 33 and 34. A simple flexible pipe might be used for connecting the pipe 29
with the supply pipe 30 shown in Fig. 5.

page_text: The bore 22 of the tubular piston-rod 22 is connected by a pipe 22° with the
valve-chest 3 of the percussion-cylinder 3, for the purpose of conducting
motive fluid from the rear end of the feed cylinder 21 to said valve-chest.
Between the feed-cylinder 21 and the percussion-cylinder 3 there is arranged a
friction-clamp for the purpose of regulating the feed. This friction-clamp, which
is shown in section in Fig. 4, consists of two blocks of wood 35 and 36 placed
between two metallic plates 37 and secured together by means of two bolts 38 & 39,
provided with nuts, one of which, viz.: that on the bolt 39, is provided with a
handle 40 for the purpose of easily regulating the pressure of the said clamp on
the piston-rod 22.
A helical spring 41 is secured to the piston-rod 22 in such a manner as to
prevent the rear end of the cylinder 22 from receiving an excessive shock in case
the piston 24 should move back very rapidly.
The weight of the frame 4 and the cylinders and other parts carried thereby
may advantageously be counter-balanced by means of weights and chains passing
round overhead pulleys so as to enable the frame to be easily raised by hand when
not in use.
The weights may however, if desired, be omitted and the chains be arranged to
be operated by means of hydraulic, steam, or other power, in a manner that will
be readily understood without drawings.
When it is desired to tap the metal from the blast-furnace, the frame is brought
by hand or otherwise into the position shown in Figs. 1, 2, and 5. In order to
prevent the frame from then turning about the vertical bar 8, the cross-bar 7 is
secured to the eye 13 by means of the bolt 10 and pin 11. The three-way cock 27
is now turned into the position shown in Fig. 3 and motive fluid is allowed to enter
both ends of the cylinder by means of the pipe 26. The motive fluid will thus
traverse the bore 22" of the piston-rod 22 and the pipe 22 and reach the valve-
chest 3 of the percussion-cylinder 3 and so cause the percussive action of the
drilling tool 3*.
At the same time, as the fluid in the front portion of the cylinder 21 presses in
a backward direction on the piston 24 only, whilst the fluid in the rear portion of
the said cylinder presses in a forward direction both on the piston 24 and on the
inner closed forward end of the piston-rod 22, the piston 24, the rod 22 and the
percussion-cylinder 3 will be forced forwards by the difference of these two
pressures. The feed may be controlled by means of the handle 40 of the friction-
clamp and the percussive action may be regulated by means of the three-way
cock 27 or of a cock that may be placed in the pipe 22b. As soon as the molten
iron is reached, the friction-clamp is loosened and the three-way cock 27 is turned
so that the rear end of the interior of the cylinder 21 is put into communication
with the exhaust-pipe 28 and its communication with the pipe 29 is broken. This
causes the piston 24 to be immediately and quickly forced back and the drilling
tool to be thus removed from the tap-hole 2. The supply of motive fluid having
been cut off from the apparatus, the cross-bar 7 is detached from the eye 13 and
the frame 4 with its cylinders and attached parts is swung by means of the
bracket 19, in the direction of the arrow in Fig. 2 into such a position as to be out
of the way of the casting-operations.
By my invention considerable labour is saved in the tapping of a blast furnace ;
the tap-hole is formed much quicker than by a hand operated bar or drill; and a
better shaped tap-hole is obtained than by the latter means, with the result that
the tapping-hole which will have nearly a circular shape, will stand longer against
cutting out by the molten iron and cinder than has heretofore been usual.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what 1
claim is :-
1. In tap-hole drilling apparatus for blast furnaces, an adjustable drill mounted
on a frame that is adjustably connected to or suspended from a movable or swinging

page_text: bracket or support and has one of its ends detachably and adjustably mounted on a
separate support whereby it can be readily held in operative position substantially
as herein described.
2. Tap-hole drilling apparatus of the kind referred to in the preceding claim in
which one end of the frame is suspended from a cross bar or equivalent means
adapted to be detachably secured between two side supports or pillars in proximity
to the tapping-hole substantially as herein described.
3. Tap-hole drilling apparatus for blast furnaces, comprising a frame carrying
the drilling tool, a swinging support therefor, means for raising and lowering either
end of the frame, a feed cylinder attached to the frame and having its piston
connected with the percussion cylinder of the drill, a motive fluid supply pipe, and
a flexible connection leading from said supply pipe to the feed cylinder substantially
as herein described for the purpose specified.
4. My improved tap-hole drilling apparatus for blast furnaces, constructed and
arranged substantially as herein before described with reference to and shown in
Figs. 1 to 4 inclusive of the accompanying drawings, or modified according to
Fig 5
Dated this 13th day of July 1894.
For the Applicant,
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.