Improvements in Galvanizing Iron and Steel.
Year: 1892

page_text: Date of Application, 10th Feb., 1892
Complete Specification Left, 10th Nov., 1892-Accepted, 10th Feb., 1893
PROVISIONAL SPECIFICATION..
Improvements in Galvanizing Iron and Steel.
I, WILLIAM KNIBB GREENWAY of Bradley Field Iron Works, Bradley, near
Bilston in the County of Stafford, Galvanizer, do hereby declare the nature of this
invention to be as follows:-
:-
This invention pertains to the zincing, or coating with zinc, of iron and iron or
steel plates, tubes and other like articles, and commonly known in commerce as
galvanizing.
Heretofore this said process of galvanizing has been carried out, by first
preparing & cleaning the metal to be coated by pickling, scouring and washing,
and then immersing the said prepared sheets or articles into a bath of molten zinc,
covered with salammoniac or other suitable flux.
The flux prevents or deters the volatilization of the zinc, and prevents the
adhesion of oxides to the plates to be coated, on their immersion, into the bath
or pot.
These, said baths or pots are made of iron, and in consequence of zinc having
a considerable power of dissolving iron, rapid corrosion of the insides of the pots
ensues, and further, in consequence of the presence of foreign matters, such as
charcoal, in zinc, voltaic action ensues, and the pots, besides being eaten away by
corrosion, are also destroyed at points where the said voltaic action occurs.
Another great disadvantage in the process of zincing, is the necessary employ-
ment of fluid zinc in great bulk, in order that the heat extracted by the plates
immersed, shall be replaced inappreciably by the specific heat of the bulk of the
same.
By thus employing zinc in considerable bulk, great loss is occasioned by volatili-
zation and deterioration, by combining with the iron of the bath or pot con-
taining it.
The object of my invention, is first, to make the baths or pots more lasting;
secondly, the employment of a smaller quantity of zinc than is usually employed,
hence less volatilization; thirdly, keeping the fluid zinc up to its normal tem-
perature, and conveying the specific heat thereto, through the intervention of a
surrounding and fluid metal, contained within a second and outer bath, and fourthly,
the employment of a bath within a bath, in which the inner one, which contains
the fluid zinc, may be of a cradle or other form.
In carrying out my invention, I take an outer metal of wrought iron or other
material, and I arrange or dispose within the middle, or interior of the same, and
inner and smaller vessel, wherein molten zinc is placed.
The second and inner vessel may be made separate from or integral with the
outer one, in manner that molten lead contained within the latter, shall not, by its
higher specific gravity, displace the smaller one, viz.; that which contains the zinc,
and which is fitted or supplied with rolls, and which rolls may be driven by
machinery, to carry the plates or objects to be coated, through the fluid metal,
contained within the said inner vessel, at any velocity previously determined upon.
In the case of a dipping pot, no rolls are employed.
The said inner vessel may be fitted with guide and other usual appliances.
The lead contained within the outer pot or bath, is covered with a flux of sal-
ammoniac, grease or the like, whilst the pot itself is set in brickwork, and provided
with fire, flues and chambers, for the efficient heating of the same.
Zinc within the inner vessel is also protected by flux, and further, the top edge of
the inner not or bath may be on the same level as the outer one, and the bottom of

page_text: the inner pot, may, if necessary be elevated, with a space between it and the
lower one.
Fluid zinc may be placed in the inner pot, and lead is melted up in the outer one.
The heat lost from the former consequent upon dipping, is replaced, and the normal
temperature of the fluid metal kept up. by the transmission of the latent heat of
the fluid lead contained within the vessel surrounding the zinc.
Thus, in the galvanizing of iron plates, the same are duly pickled, prepared and
washed, and then passed into, or through the zincing pot when the heat extracted
from the zincing metal, is replaced by the transmission of the heat from the
surrounding metal, by conduction to it.
propose that the surrounding lead, which is heated through the outer vessel,
which is in contact with the heating flues, should be superheated above its fusing
temperature, and hold sufficient latent heat, which is transmitted through the pots
as aforesaid, to replace the heat lost by dipping and radiation.
Or the sides of the inner pot may be at a lower level than the sides of the outer
one, and the surface of the zinc of the inner one, shall be above the level of the
lead within the outer one, so that the zinc floats upon the top of the lead, thus
forming a uniform metal surface, common to both the inner and outer pots.
Dated this 9th day of February 1892.
COMPLETE SPECIFICATION.
Improvements in Galvanizing Iron and Steel.
I WILLIAM KNIBB GREENWAY, of Bradley Field Iron Works, Bradley, near
Bilston, in the County of Stafford, Galvanizer, 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:-
My invention relates to pots or vessels employed in galvanizing metals, and
consists in providing the said pots with surrounding interspaced sides, or sides
having jackets or outer casings, and located within the said interspaced part, or a
surrounding pocket, between outer casing and inner chamber, is a fluid metal, which
melts at a lower temperature than the galvanizing metal to be melted, and kept
fluid in the inner chamber, and through which interposed fluid metal, the specific
heat of the fire from a surrounding fire place passes, to the inner chamber
'or pot.
Thus the inner chamber containing the galvanizing metal is heated, through the
medium of a surrounding and interposed fluid metal, located within the continuous
pocket or interspace between the outer and inner walls of the pot.
Figure 1 of the accompanying drawing represents in cross vertical section, a
galvanizing pot, having an intervening space between the inner and outer walls of
the same, for the reception of fluid metal, such as lead or tin, and which forms the
medium for conveying the specific heat from the outside walls of the pot, to the
inside walls of the pot, or to the inner compartment wherein the galvanizing metal
is melted.
The outer and inner walls of the said pot are made integral or in one piece with
the bottom, and which outer part may be flanged, banded or plain, and with the
flues of the fire place arranged to encircle or encompass the said outer side walls,
upon which the Hame, and the heated products of combustion, play.
Figure 2 represents a top side plan of the same, showing the continuous inter-
vening space between the inner and outer side parts of the vessel, or in other words,
showing how the two parts, constitute, as it were, space separated vessels,
Figure 3 is a side elevation of the pot Figures 1 and 2.

page_text: Figure 4 represents an interspaced pot, formed by rivetting an inside wall,
forming the inner compartment of the same, to the bottom.
In Figures 1, 2 and 3, a is the chamber or inner pot for containing the zincing
metal, and b is an outer vessel or bath, with the inside walls of the same interspaced
from the side walls a³, of the inner pot a, and which said inner pot is made in this
case in one piece with the outer vessel, bath or the like b. c is the intervening
space, between the inside surface of the outer walls b, and the outside surface of
the walls a², of the pot a, and d is the bottom of the combined or side interspaced
pot, and within which interspace c, fluid metal, which melts at a lower degree of
heat than the zinc contained within the middle pot, is located, and forms the medium
for the transmission of the heat from the fire of the surrounding furnace to the
galvanizing metal to be melted or kept fluid.
In Figure 4, the inner pot a, consisting of an inner chamber, with surrounding
walls a', open at top and bottom, is affixedly connected to the middle of the bottom
of the outer chamber b, by angle iron a³, connected respectively to the sides a³, and
bottom b', by rivettings or otherwise, thus leaving a space c, between the pot a, and
an outer vessel or jacketing b.
Instead of connecting the lower edges of the inner pot to the bottom which is
common to both pots, by rivetting, the same may be electrically or otherwise
welded or connected as may be desired.
The bottom of the pot rests upon brickwork in setting.
I wish it to be understood that I do not confine myself to the shape or dimensions
of the pot, or to the dimensions of the intervening space between the outer walls of
the same, as these particulars may be varied, according to the character of goods
to be coated or galvanized.
By my invention, the direct action of the fire is cut off from its connection with
the galvanizing pot, galvanic wholly or partly prevented, loss of heat greatly
reduced, burning of the galvanizing metal and pot prevented, hence the rendering
of the said pot more lasting.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
First-Pots for galvanizing, consisting of a side interspaced vessel, pot or bath,
with a bottom common to both the outer and inner walls of the same, substantially
as, and for the purpose described and set forth.
Secondly In an interspaced galvanizing pot, vessel or bath, making the inner
and outer walls, and also the bottom of the same in one piece, as described and set
forth in Figures 1, 2 and 3.
Thirdly:-A side interspaced galvanizing pot, vessel or bath, substantially as
and for the purpose as, described and set forth.
Dated this 9th day of November 1892.
WILLIAM KNIBB GREEN WAI,
By Henry Skerrett,
6, Livery Street, Birmingham, Agent for Applicant.