Method of, and Apparatus for, Removing Oxide or Scale from Sheet Metal Plates and the like
Year: 1897

page_text: Date of Application, 8th Nov., 1897
Complete Specification Left, 16th July, 1898-Accepted, 29th Oct., 1898
Method of, and Apparatus for, Removing Oxide or Scale from Sheet
Metal Plates and the like.
•
I, FRANZ GASTELL, of 23, Fischthorplatz, Mombach, near Mainz, in the German
Empire, Manufacturer, do hereby declare the nature of this invention to be as
follows:-
This invention relates to a method of, and apparatus for subjecting sheet metal
plates to the action of the sand blast for the purpose of removing oxide or scale
therefrom and it has for its object to obviate the disadvantages of the apparatus
now in use, to render the action of the blast more efficient, and to enable the
working space in which the operation is performed to be more completely enclosed.
According to this invention the sheet metal plates are first bent into cylindrical
form whereby dents or bulges are removed and the scale loosened, and are then
moved in a helical path past a stationary blast nozzle and are finally straightened
or flattened.
In order that the sand blast should act efficiently it is necessary to prevent all
elastic yielding of the plate at the place under treatment and this is effectually
attained by bending the plate to cylindrical form so that it acts as an arch and
consequently has the necessary stiffness to allow of the most favourable action
of the sand blast, the preliminary bending of the plate having also the effect of
loosening the layer of oxide or scale.
According to this invention the plate after being bent to cylindrical form is
held without additional support about a mandrel fixed upon a table mounted upon
a vertical shaft and receiving helical motion whereby the whole surface, of the
plate can be readily traversed in front of a stationary blast nozzle whereby the
flexible rubber tubing heretofore used for enabling the nozzle, to be traversed
across the plate may be dispensed with. The plate thus mounted revolved and
traversed in front of the blast nozzle, is enclosed within a cylindrical dust-tight
casing into which the blast nozzle projects and from which the dust can be readily
blown out at the termination of the operation. The shaft on which, the table is
mounted is hollow and is provided at foot with a screw nut which works upon a
stationary leading screw which rises within a hollow shaft. The latter is rotated
and consequently raised by means of a belt pulley in connection with it by a
key and groove but which is prevented from moving axially by a supporting
bracket. Below the casing there is provided an annular trough for the reception
of the falling sand and within the circle of this trough there is a collar bearing
for the shaft. In order to keep this bearing dust-tight and shut it off from the
working space, there is provided a loose joint ring which rotates upon a stationary
joint surface without partaking in the axial movement of the shaft, an extensible
dust tight sleeve connected with the underside of the table extending downwards
over the joint between the two surfaces so that the ring which always bears

page_text: lightly upon the stationary surface makes a perfectly tight joint therewith.
Means are provided whereby the motion is reversed when the highest position
is reached and whereby at the same time the blast is admitted without sand to
blow out the dust contained in the enclosing trunk or casing.
Dated this 8th day of November 1897.
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.
Method of, and Apparatus for. Removing Oxide or Scale from Sheet
Metal Flates and the like.
I, FRANZ GASTELL, of 23, Fischthorplatz, Mombach, near Mainz, in the German
Empire, Manufacturer, 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:-
In using the sand blast for removing the layer of oxide or scale from the surface
of sheet metal plates it has heretofore been the practice to subject the flat plates
as they come from the rolls to the action of the sand blast by moving them on a
suitable carriage to and fro in front of the blast jet and shifting the blast nozzle
up and down after each movement of the carriage. Then in order to remove
dents or bulges from the plates thus acted on and render them completely flat,
the plates have been first bent to cylindrical form between rolls and afterwards
straightened or flattened out.
The apparatus which have been employed for this purpose possess many dis-
advantages. For example, the carriage carrying the plates is, together with its
travelling rollers and rails, situated in the immediate vicinity of the place of
working, and is therefore exposed to the action of the dust as well as to con-
siderable wear and tear; the chamber in which the operation takes place must
have an elongated rectangular form of at least double the length of the plate,
and the removal of the dust is very difficult; and as the shifting of the carriage
itself up and down is inconvenient the blast nozzle has to be moved up and down,
and it is therefore necessarily connected by means of a rubber tube with the blast
pipe which necessitates the expense of large amount of flexible tubing. More-
over, owing to the motion of the nozzle and of the mechanism for driving the
carriage, it is very difficult to guard against the escape of dust into the machine
shop.
These disadvantages are wholly obviated by the present invention, according
to which the sheet metal plates are first bent into cylindrical shape and while in
this condition are moved in a helical path past a stationary nozzle and finally
straightened or flattened out. The chief advantages obtained by this method
are the more efficient action of the jet upon the whole surface of the plate and the
possibility of easily and completely shutting off the working space from the rest
of the machine. The plate as it comes from the rolls is not sufficiently stiff to
support itself over its entire surface while in order that the sand blast should act
efficiently, it is necessary that all elastic yielding of the plate at the place under
treatment should be prevented. For this purpose only complicated and inefficient
apparatus have hitherto been available When, however, the plate is bent to a
cylindrical shape it acts as an arch and thus possesses, without adventitious aid,
the necessary stiffness to allow of the most favourable action of the sand blast.

page_text: According to this invention the carriage heretofore used is replaced by a table
the axis of which receives a helical motion and which can be readily enclosed
dust-tight and as the whole shifting movement is imparted to the article under
treatment the nozzle is stationary and the flexible rubber tubing dispensed with.
The previous bending of the sheet or plate into cylindrical form loosens the layer
of oxide or scale and the cylindrical plate does not require any additional support
during the operation but is self-fixing upon the revolving table whereon it
remains unmoved during treatment. The size of the working chamber need no
longer be more than the double width of the work but only of the single width of
The working chamber thus assumes the shape of a cylindrical trunk
from which the dust can be very readily blown out.
the same.
The accompanying drawings shew the apparatus in longitudinal section.
A is the revolving table which is mounted on the hollow shaft. B and is pro-
vided with a small guiding cylinder or mandrel a on which the sheet metal
cylinder is placed. C is the enclosing trunk or casing to which access is obtained
through a door and into which the nozzle D of the sand blast projects. In the
foot of the hollow shaft B there is fixed a screw nut f which works on the
stationary leading screw F. The hollow shaft is rotated and consequently also
moved upwards by means of a belt pulley in engagement with the hollow shaft
by means of a longitudinal key or feather but which is itself prevented from
moving axially by means of the transverse bars hh of its supporting frame or
bracket H. Above this bearing there is provided the annular trough K for the
falling sand, and a collar bearing 6 for the shaft B. In order to keep this bearing
dust-tight and in order to shut off the entire enclosing space dust-tight from
the working space there is provided a loose joint or packing ring M which rotates
with the shaft B upon a stationary joint surface N without partaking in the
axial movement of the shaft, and a dust-tight sleeve or tubular curtain L of any
suitable fabric attached to the underside of the table extends down to and over
the ring M to which it may or may not be attached so as to rotate therewith and
which may cover the joint between the surfaces of M and N. Thus the ring M
bears always lightly by its own weight upon the surface N and makes a perfectly
tight joint therewith.
The apparatus is provided with known devices for the purpose of reversing
the motion when the highest position is reached, and with means whereby at the
same time the blast which serves to operate the sand jet is then admitted without
sand into the trunk to blow out the dust contained therein.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
1. The herein described method of subjecting sheet metal plates, and the like,
to the action of a sand-blast, which method consists essentially in bringing the
plate to cylindrical form and rotating it in a helical path past a stationary sand
blast nozzle substantially as specified.
2. The herein described method of treating sheet metal plates for the purpose
of removing irregularities and adherent oxide or scale, which method consists in
bringing the plate to cylindrical form and rotating it in a helical path past a
stationary sand-blast nozzle substantially as specified
3. The apparatus for carrying out the process specified, consisting essentially
of the table provided with a mandrel for holding the cylindrical metal or other
plate mounted upon a shaft and rotated and traversed so as to be caused to move
in a helical path by a leading screw, in combination with a fixed sand blast nozzle
which together with the table, is enclosed within a dust-tight casing substantially
as described and shewn in the drawings.
4th. The dust-tight joint for the bearing of the shaft, consisting of the loose

page_text: ring adapted to rotate on a fixed surface without partaking in the axial movement
of the shaft and the extensible dust-tight sleeve attached to the underside of the
table and extending over the joint substantially as specified.
Dated this 16th day of July 1898.
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.