Improvements in the Process of Coating or Cleaning Metals.
Year: 1891

page_text: Date of Application, 10th Jan., 1891
Complete Specification Left, 9th Oct., 1891-Accepted, 21st Nov., 1891
PROVISIONAL SPECIFICATION.
Improvements in the Process of Coating or Cleaning Metals.
I, RICHARD HEATHFIELD of Darlaston in the County of Stafford Manufacturer
do hereby declare the nature of my said invention to be as follows:-
My invention has for its object improvements in the process of coating or
cleaning metals such for instance as galvanizing or tinning and it relates more
particularly to that portion of the process in which the objects, whether sheets or
otherwise are prepared before immersion in the bath of molten coating metal or
before the application of the coating metal to the particular object under treatment.
I will for the purpose of explanation confine myself to the process known as
galvanizing sheets, although it must be hereafter obvious that the process can be
applied to cleaning sheets or plates or other objects which are afterwards coated
with molten metal.
Hitherto the general mode of procedure has been to immerse the sheets of iron
or steel to be coated in a bath of acid which is known as a pickling bath and which
has the effect of removing the scale and surface impurities therefrom which scale
and other impurities are when removed held more or less in solution in the pickle
thus deteriorating it very rapidly and of rendering it practically useless for the
purpose of pickling or cleaning consequently frequent renewals of acid are necessary
unless the waste or diluted pickle is evaporated or otherwise dealt with so as to
remove the iron and other impurities and recover the hydrochloric or other acid for
reuse. In any case however great expense is constantly necessary to maintain the
pickling bath in a good and effective condition. By my invention to reduce this
expense I proceed as follows:-
"
treat the sheet which it is desired to galvanize or coat with a current of
electricity produced by a dynamo or other means as is well known. The sheet or
object of iron or steel or other metal it is desired to operate upon is immersed in a
suitable solution or bath for depositing the particular metal about to be pickled
and is treated as an "anode" in the electroplating process, that is to say, the
electric current engendered by the dynamo or other agent being passed through
the sheet about to be cleaned and which being attached to the positive pole of the
dynamo is acting as an " anode gradually strips its outer surface sufficiently to
prepare it for immersion in the coating bath and causes the deposit of iron or steel
or other metal upon the cathode which of course is in connection with the negative
pole of the dynamo or other agent and the metal or depositant which in the
ordinary pickling process would be lost may be reworked into useful material. The
time for this intermediate step in the process will be regulated by the strength of
the electric current passed through the sheet or other object and the kind of metal
operated upon. It will be obvious that a number of sheets or other objects may
be connected up together and operated upon at the same time in suitable tanks or
baths.
Dated this 9th day of January 1891
GEORGE BARKER,
77, Colmore Row, Birmingham, Agent for Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in the Process of Coating or Cleaning Metals.
I, RICHARD HEATHFIELD of Darlaston in the County of Stafford, Manufacturer
do hereby declare the nature of my said 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 has for its object improvements in the process of coating or
cleaning metals as for instance is required in the galvanizing of sheets or the coating
of sheet iron or steel with tin and the coating of various objects with various metals
and it relates more particularly to that portion of the process in which the objects
whether sheets, plates, wire, buckets, tubes, or otherwise are prepared immediately
before immersion in the bath of molten coating metal or immediately before the
application of the coating metal to the particular object under treatment. I will
for the purpose of explanation confine myself to the process known as galvanizing
sheets but from which the application of the process to other articles will be quite
evident. Hitherto the general mode of procedure has been to immerse the sheets
of iron or steel in a bath of acid which is known as a "pickling bath" which has
the effect of removing the scale and surface impurities therefrom which impurities
are afterwards held more or less in solution in the pickle which is thus deteriorated
very rapidly and thereby rendered practically useless for the purpose of pickling.
In consequence of this, frequent renewals of acid are necessary unless the waste or
deteriorated pickle is evaporated or otherwise dealt with so as to remove the oxide
of iron and recover the hydrochloric or other acid for re-use. In any case however
great expense is constantly necessary to maintain the pickling bath in good and
effective condition. By my invention in order to reduce this expense and to do
the work more effectively and to render the process more continuous I proceed as
follows:-
I treat the sheet or other articles which it is desired to galvanize or coat with
electricity produced by a dynamo or other equivalent or similar means in a bath
suitable for depositing the particular metal under treatment such for instance as a
bath composed of copperas or of chloride of iron, and in this bath the sheet or
other object to be cleaned is treated as the "anode" in the electroplating process
that is to say the electricity engendered by the dynamo or other agent being
passed through the sheet or sheets from the positive pole of the dynamo strips its
outer surface sufficiently to prepare it for immersion in the coating bath. The
metal so stripped off the metal sheet or sheets or other articles acting for the time
as the "anodes" is deposited upon another sheet or sheets or objects in the bath
which for the time being are acting as
"cathodes." The time occupied in doing
this will be determined by the effect produced upon the plates or sheets which will
be regulated by the nature of the bath and the strength of the electric current
passed through it and the kind of metal operated upon. It will be obvious that
almost any number of sheets or other objects may be connected up together and
operated upon at the same time in suitable tanks or baths in connection of course
with the necessary cathodes.
"
The accompanying diagram drawing illustrates sufficiently the process of
preparing sheets or other articles for coating:
The pickling tank or bath B may be of almost any shape or size to suit the
articles to be treated.
The sheets E to be stripped which constitute the "anodes" may be supported
in any convenient manner in the bath B so that they may be connected up to the
positive pole P of the dynamo or other electrical agent A and the sheets or other
articles K which constitute for the time being the
"
cathodes are also supported
in a similar manner so as to be connected up by N to the negative pole of the
electrical agent. When the articles acting as anodes are sufficiently stripped or
66

page_text: cleaned they are removed from the bath B and coated in any desired manner or
with any desired coating as will be well understood.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is :-
The improvements in the process of coating or cleaning metals by treating them
in the preparatory stage by electricity, substantially as and for the purposes herein
set forth.
GEORGE BARKER,
77, Colmore Row, Birmingham, Agent for Applicant.