IMPROVEMENTS IN GALVANIZING SHEET IRON AND IN MACHINERY OR APPARATUS THEREFOR
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by the said Joseph Tinn at the Office of
the Commissioners of Patents on the 18th April 1888.
JOSEPH TINN of the city of Bristol, "IMPROVEMENTS IN GALVANIZING SHEET
IRON AND IN MACHINERY OR APPARATUS THEREFOR,"
"
This invention which relates to improvements in galvanizing sheet iron and in
machinery or apparatus therefor, is designed to impart to the sheets clean and
uniformly galvanized surfaces and to reduce the labour hitherto requisite. To effect
these objects, the rolls through which the sheets are made to pass are arranged and
placed as hereinafter described.
At one side of the vessel containing the molten zinc or spelter, is placed a pair
of rolls fitted with the usual screw gear for regulating the pressure exerted upon
the sheets which are fed therethrough to the bath. This pair of rolls is wholly
free from contact with the molten metal contained in the bath. At the delivery
side of the bath, opposite to that at which the aforesaid rolls are placed is another
pair of rolls which receives the sheets after passage through the bath, the sheets
being conducted to the last mentioned pair of rolls by means of guides fixed in
position for this purpose in the bath. The uppermost of these latter or finishing
rolls may be made hollow for the purpose of being heated by a steam or gas jet
or by other desired means. The lowerinost of the pair of finishing rolls is partially
immersed in the bath, to the extent of one half, the molten metal being maintained
at or near the necessary level therefor. The pressure exerted upon the sheets by
the finishing rolls is regulated by screw gear similar to that with which the feed
rolls are fitted, and, the sheets being out of the bath at the point of pressure of
the finishing rolls, an uniform coating and an even degree of finish are imparted to
the sheets.
To obviate the adhesion of scum or crust of the spelter to the sheets, before
being received by the finishing rolls, an additional roller having a fluted or grooved

page_text: surface is placed in front of the finishing rolls to prevent, in its revolution, the
accumulation of such scum or crust at that point. Subsequent washing and drying
of the sheets are rendered unnecessary. The feed and finishing rolls are adjusted
to such an angle and the guides are so curved that the sheets are not subjected
to any undue bending or distorting stresses, and, a comparatively small portion of
the framing in which the rolls are carried being immersed in the bath, chemical
action and reaction of the metals are lessened and the value of the dross is enhanced
accordingly. The "wash" of the molten metal is also lessened and hence the wear
on the vessel containing it is proportionately reduced.
The sheets, after passing through the finishing rolls, may be mechanically
delivered on to an endless travelling table by which they may be conveyed direct
to be sorted.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Joseph Tinn in the Great Seal Patent Office on the 16th October
1883.
JOSEPH TINN of the City of Bristol
IMPROVEMENTS IN GALVANIZING SHEET
IRON AND IN MACHINERY OR APPARATUS THEREFOR
This invention consists in arranging the pressing or finishing rolls at the side
of the pot at which the sheets are withdrawn, in such manner that the horizontal
axis of the lowermost roll is in the same plane with the surface of the molten
metal of the bath, so that the said roll is immersed to the extent of about one half
of its diameter throughout the width of the bath. The uppermost roll, which may,
if desired, be made hollow for the purpose of conducting therethrough a jet of
steam, gas or other heating agent, bears upon the lowermost roll in the usual
manner. Thus the sheets are not, as hitherto, subjected to immersion after passing
through the finishing rolls.
At or near the point where the sheets are received by the pressing or finishing
rolls, is placed a fluted or grooved roller which by its rotation drives off the crust
or scum of oxidized spelter formed on the surface of the molten metal. The
adhesion of such crust or scum to the surfaces of the sheets is thereby obviated
and the sheets are delivered from the rolls with a clean and uniformly smooth
surface free from salt stains or other defects.
The sheets are introduced into the bath through feed rolls placed at the desired
angle at the side of the bath opposite to the pressing or finishing rolls to which
they pass by means of guide bars without being subjected to undue bending or
distorting strains,
And in order that my said invention may be properly understood, I now proceed
more particularly to describe the same with reference to the accompanying sheet
of illustrative drawings and the figures and letters marked thereon.
Fig. 1 on the accompanying sheet of drawings represents a longitudinal section,
taken at A. B, Fig 2, which is a plan, of a galvanizing pot or tank having the
various rolls arranged in accordance with my invention. The lower pressing or
finishing roll C is so placed that its horizontal axis coincides with the level of
the surface of the molten metal indicated at Fig 1 by the dotted line E. F.
The upper roll D of the finishing rolls bears upon the roll C, as shown, and may
be, if desired, made hollow for the purpose of conducting therethrough a jet of
steam, gas or other heating agent.
Under this arrangement, the sheets being galvanized are not, as hitherto, sub-
jected to immersion after their passage between the finishing rolls.
At or near the point where the sheets are received by the finishing rolls C. D,
is placed a fluted or grooved roll G, which, in rotating, drives off the crust or scum
of oxidized spelter formed on the surface of the molten metal in the bath H. The
adhesion of such crust or scum to the surfaces of the sheets is thereby obviated
and the sheets are delivered from the rolls free from salt stains and other defects,
and with a clean and uniformly smooth surface. Subsequent washing and drying
of the sheets are dispensed with.
The sheets are introduced into the bath H through the feed rolls M. N, placed
at the desired angle at the side opposite to the finishing rolls C. D, to which the
sheets are conducted by the guides P supported at each side of the pot or tank
and extending into and across the bath, as shown. The sheets may be delivered
from the finishing rolls C. D direct to an endless travelling table whereby they
may be conveyed to the sorters.

page_text: The plane of revolution of the rolls is such that a proper bearing surface is in
contact with the sheets passing through them, and the sheets pass therefrom
.without having been subjected to undue bending or distorting strains.
A comparatively small portion of the framing in which the rolls are fitted being
immersed in the bath, the action and re-action of the metal of which the framing
is constructed upon the spelter in the bath are propionately [sic] decreased.
Having now described my said invention and the mode in which the same is or
may be used or practically carried into effect, I claim as the invention secured to
me by the hereinbefore in part recited Letters Patent.-
The arrangement of the rolls in connection with the bath for galvanizing sheet
iron, substantially as herein before described and shown on the accompanying sheet
of drawings, whereby the sheets are delivered having the surfaces uniformly clean
and smooth and free from oxidized spelter.
In witness whereof I, the said Joseph Tinn have hereunto set my hand and
seal this fifteenth day of October in the year of our Lord one thousand eight
hundred and eighty three.