Improvements in the Method of and Apparatus for Producing Cylinders, Pipes, and other Tubular or Hollow Bodies of Glass.
Year: 1891

page_text: Date of Application, 24th Nov., 1391-Accepted, 16th Jan., 1892
COMPLETE SPECIFICATION.
Improvements in the Method of and Apparatus for Producing
Cylinders, Pipes, and other Tubular or Hollow Bodies of Glass.
A communication by ROGER SHERMAN PEASE, of Minneapolis, in the County
of Hennepin and State of Minnesota, United States of America.
I, WILLIAM PHILLIPS THOMPSON F.C.S., M.I.M.E, of the Agency for
Foreign Patent Solicitors, 6, Lord Street, Liverpool and 6 Bank Street,
Manchester both in the County of Lancaster and 323 High Holborn in the
County of Middlesex, Civil Engineer, 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:-
This invention relates to the formation of cylinders, pipes and other tubular or
hollow bodies of glass, and consists essentially in lowering, into a mass of molten
metal, the depending skirt or flange of a bait; raising said bait to form a film or
sheet, and, while raising the same, forcing air into the interior of the body thus
produced, thereby expanding the same to the desired diameter, the air pressure
being continued during the upward movement or drawing operation to prevent the
drawing in of the body, but the pressure being made only sufficient to maintain
such diameter without further variation.
It is not essential that the enlarging operation be performed, though it is deemed
quite desirable that it should be, as it is thereby possible to make use of a much
smaller bait, and to start the drawing operation under more favourable conditions
than would otherwise exist.
If it be desired to reduce the diameter, the air pressure is so far reduced as to
permit the drawing of the metal toward the centre to the required extent.
The invention also consists in other features and details hereinafter explained.
In the accompanying drawings is represented an apparatus suitable for carrying
out the above described process, but the invention is not restricted to the specific
construction therein shown, as it may be variously modified without departing from
the spirit and scope of the invention.
Figure 1 is a perspective view showing so much of the apparatus as is needed
to make clear the description which follows ;-
Figure 2, a sectional elevation showing the arrangement of the parts in a similar
form;
Figure 3, a sectional view of the mouth piece of the blowing tube, showing an
outwardly closing check valve, which is designed to prevent back pressure or
escape of air from within the body which is being drawn or produced.
The apparatus consists essentially of a containing vessel A, advisably formed
with an annular chamber a to receive and contain molten metal, the raised central
boss being carried upward to or preferably above the level of the outer wall of
the vessel, as indicated in Figure 2, and having a central passage or opening to
permit the delivery of air to the hollow body being formed.
In practice, it is found advisable to arrange the vessel A for use in connection
with supply pots or tanks so arranged as to deliver directly into said vessel, and,
with this object in view, one or more chambers B are provided, within which are
arranged melting pots Ċ or tanks, as may be preferred, the pots being represented
in the drawing and deemed preferable for general purposes.
The bottom wall or floor of the chambers B is extended from one chamber to
the other as indicated, or it may be simply an extension of the floor of one of said
chambers, and is furnished with an opening D, which is so fashioned and pro-
portioned as to permit the insertion of the vessel A. into it from below, and to

page_text: cause the inner wall of the chamber a of said vessel to come flush with the over-
hanging walls of the opening D.
For convenience of handling and manipulation, the vessel A is mounted upon
the enlarged top or platform d of a vertically movable column E, which is repre-
sented in Figure 2 as externally threaded, and grooved to receive a guiding pin
or bolt e, which projects into the groove, after passing through a supporting
base and encircling and meshing with the threaded portion of the standard or
column E is a nut or hand wheel G, which, being turned in one or the other
direction, causes the rise or fall of the standard E, and, consequently, of the
vessel A.
As shown in Figure 2, the standard E is provided with a central opening 9,
which registers with and forms a continuation of the central opening or passage
of the vessel A, when said vessel is placed in position upon the standard E.
To ensure a proper register of the openings c and g, the vessel A is formed
with a central recess in its under side, and the platform d is formed with a corre-
sponding boss which enters and accurately fills said recess, and serves the further
purpose of centering the vessel upon the platform and holding it against accidental
displacement.
To further ensure a tight joint and prevent the escape of air between the plat-
form d and the vessel A, a sheet of asbestos packing may be introduced between
them, as indicated in Figure 2.
The passage or opening g extends downward in the standard E to a suitable
point, and then turns laterally and extends outward through a nipple i which is
threaded to receive a coupling or union, by which the blow pipe or air supply
tube H is connected with the apparatus.
I indicates a bait, which is advisably made of glass, though not restricted
necessarily to glass, but iron or other substance may be used. This bait is
formed with a central knob or projection on its top, and with a depending
flange or skirt at its periphery, as indicated in Figures 1 and 2.
This knob is designed for the attachment of a clamp or crab J, which is suspended
by a chain or cable K passing over a pulley above the apparatus, and thence to
any convenient drum or windlass by which the crab, the bait, and the cylinder
may be raised as required.
With the apparatus constructed and arranged as above described, the operation
is as follows; the knob k of the bait I is secured within the clamp or crab J, and
the latter is lowered carefully until the depending skirt or flange thereof, dips
into the molten metal of the vessel A, and it is allowed to remain there a sufficient
length of time to cause said bait to become partially fused and unite with the
molten metal of said vessel.
The chain or cable is then wound upon the windlass, or is otherwise drawn up
at a suitable rate of speed and the film or body of glass is drawn up with it
following the depending edge or skirt of said bait. During such elevation air is
forced in through the pipe H and the opening or passages and c to the interior of
the body being formed, and as a consequence the molten metal or glass film or
body depending from the skirt of the bait is enlarged, and the metal is taken
further and further from the centre of the vessel until the desired diameter is
reached, whereupon the pressure of the air forced in is reduced sufficiently to
prevent further enlargement, but is maintained at the proper point to ensure the
maintenance of the size thus determined.
As the cylinder rises and the glass is exposed to the surrounding atmosphere, it
becomes set and hardened, and possesses sufficient strength and rigidity to draw
up after it the film or body of metal required to continue the formation or pro-
duction of a cylinder of whatever length may be required. When the desired
length is attained, the upward movement of the cylinder is suddenly accelerated,
and the film is thereby drawn very thin, and either caused to break, itself, or
rendered susceptible of easy breaking, but it may be drawn up without continuing
the air pressure, in which case it tends to draw to a point and may then be readily

page_text: cut with shears in the common way of cutting glass. The cylinder is then carried
away, the ends cut off, the cylinder opened longitudinally and flattened out, and
the plate is then annealed in the ordinary way and cut up into sheets of the
required size, or may be left in one sheet if preferred.
In practice, it is preferred that the glass shall be blown or the air pressure
furnished by a glass blower in the same manner that common cylinders are blown,
that is to say, that, instead of employing mechanical contrivances for furnishing
air under pressure, it is to be blown by the attendant supplying air from his lungs
through the pipe H.
In the event of the breaking of the knob k, the slipping of the clamp J, or the
falling of the cylinder from any other cause, the contained air, which would, of
course, be highly heated, would be forced back through the passages eg and the
pipe H into the mouth and lungs of the glass blower, and would result in serious
injury to him.
To obviate this danger, a check valve M, which closes outwardly or against the
inflowing air, is provided at any point between the tip of the mouth-piece L of the
blow-pipe and the upper end of the passage or opening c. In practice, it is
preferred to locate this valve in the mouth-piece of the blow-pipe, and to construct
the same as shown in Figure 3.
As therein represented, the mouth-piece is internally threaded to permit it to
screw upon the threaded neck of an end piece or tip N. which is applied to the
pipe H, and the mouth-piece L is provided with a seat m for the valve M, which
is provided with a guiding stem carried by a cross-bar n extending across the
mouth of the tip or end piece N.
Between the cross-barn and the back of the valve M is introduced a light spiral
spring o, which serves to press the valve upward and to hold it normally against
its seat m, but with so light a pressure as to offer practically no resistance to the
entrance of air through the mouth-piece..
In order that the force with which the spring acts may be adjusted, if at any
time it is necessary to do so, the mouth-piece and the end piece or tip N are formed
with comparatively long threaded portions, so that the mouth-piece L may be
screwed on a greater or less distance, and caused to bring the valve seat m
nearer to or further from the cross-bar n.
When adjusted to the proper position, the month-piece L is clamped and held
against accidental turning by a jam nut O, or in any other convenient way.
This check valve may be used in connection with blow-pipes generally, to avoid
the necessity of placing the thumb or finger over the opening while not blowing,
as is now customary, and, when provided, it will effectually prevent the inhaling
of the hot foul air from within the cylinder, which is believed to be a prolific
cause of injury to the glass blower. It is, however, peculiarly useful and
important in connection with the method and apparatus above set forth, because
of the liability of the collapsing of the cylinder as explained.
The pipe H should be flexible in order to permit the glass blower to change his
position as desired, and also to permit the free rise and fall of the column E without
interference with said pipe.
It is obvious that a check valve may be employed which shall operate simply
by the back pressure of the air without the aid of a spring, though the spring-
actuated valve is preferred because of its greater certainty and promptness of
action.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is :-
1. The herein described method of producing hollow bodies of glass, which
consists in dipping, into a body of molten metal, the depending edge or skirt of a
bait, permitting the same to unite with the molten métal, lifting said bait, and,

page_text: during the act of lifting, supplying air to the interior of the cylinder or body.
substantially as set forth.
2. The herein described method of making glass cylinders and hollow bodies,
which consists in dipping, into a mass of molten metal, the depending skirt or
edge of a bait, permitting said bait to unite with the molten metal, lifting said
bait, supplying air to the under side of the bait under pressure sufficient to cause
the adhering glass to be expanded, continuing said operation until the desired
diameter is attained, and then lifting the cylinder steadily subject to an internal
pressure sufficient only to maintain the diameter thus produced.
3. The combination, with a vessel adapted to contain molten metal and provided
with a central opening or passage, of a bait adapted to cover said central
opening, and to dip into the metal on all sides thereof, means substantially such
as described for elevating said bait, and a blow-pipe communicating with the
central opening of the vessel, substantially as and for the purpose set forth.
4. In combination with a melting chamber or oven B having an opening D in
its floor, a vessel A adapted to contain molten metal and to fit the opening D, a
vertically movable standard or column E adapted to sustain said vessel, and a
blow-pipe H communicating with a central opening in the vessel A., substantially
as and for the purpose set forth.
5. In combination with a heating or melting chamber B having its floor provided
with an opening D, a vessel A provided with central opening c, a standard or
column E serving to support said vessel, a base F serving to receive and guide
the standard E, and means substantially such as shown and described for raising
and lowering said standard.
6. The herein described apparatus for the manufacture of glass cylinders,
etcetera, which consists of a bed or floor provided with an opening D, a vessel A.
provided with a central opening e, a supporting standard beneath said vessel, a
base F to guide and support said standard, a nut or band wheel G encircling the
standard E, and adapted to receive a screw thread formed thereon, a blow-pipe H
communicating with the passage c of the vessel A, a bait I and means substantially
such as shown and described for lowering and raising said bait to and from the
vessel A.
7. In combination with vessel A. adapted to contain molten metal, and having
a passage or opening e, a blow-pipe communicating with said passage, and provided
with an outwardly seating check valve, a bait I above the vessel A. and means for
elevating said bait.
8. In combination with the blow-pipe of a glass blowing apparatus, an outwardly
scating check valve, a spring serving to seat said valve, an end piece or tip,
and a mouth piece respectively provided with external and internal threads,
whereby the parts may be adjusted to vary the force with which the valve is
pressed to its seat.
Dated this 23rd day of November 1891.
WM. P. THOMPSON & Co.,
Agents for the Applicant.