Improvements in or appertaining to the Process of Galvanising Iron and Steel.
Year: 1889

page_text: 1889
Date of Application, 29th Jan.,
Complete Specification Left, 29th Oct., 1889-Accepted, 30th Nov., 1889
PROVISIONAL SPECIFICATION.
Improvements in or appertaining to the Process of Galvanising
Iron and Steel.
I, THOMAS BEALBY SAUNDERS, of the Firm of Saunders & Saunders, Cleckheaton
in the County of York, Manufacturing Chemists, do hereby declare the nature of
this invention to be as follows :-
This invention relates to improvements in or appertaining to the process of coating
iron or steel with zinc commonly called galvanising.
The said process commonly consists in immersing the iron or steel in a bath of
molten zinc protected from the atmosphere by a coat of muriate of ammonia which
salt is thrown on to the bath of metal in small quantities at a time during the working
of said bath. As the heat of the bath of molten zinc partly volatilises the muriate of
ammonia and partly decomposes it into gaseous ammonia it rapidly fumes away which
fumes have hitherto passed into the atmosphere therefore being entirely lost, besides
being a source of annoyance to the workmen. My improvements consist in collecting
such volatilised salt and gases passing away from the galvanising bath and recovering
them by condensation.
To carry out my improvements I fit a suitable hood or cover over each bath con-
structed to give the workmen free access thereto but adapted to collect the fumes
passing away from the bath and direct them through a conduit towards a condensing
apparatus where they are dissolved in water or other suitable solvent.
A draft or current of air artificial or otherwise may be used to assist in directing
the fumes heneath the hood or they may be drawn through the conduit by a pro-
peller. In this manner the fumes from a number of baths may be conveyed to a
common condensing apparatus and recovered.
Dated this 28th day of January 1889.
DRACUP & NOWELL,
Bradford. Agents.
COMPLETE SPECIFICATION.
Improvements in or appertaining to the Process of Galvanising
Iron and Steel.
I, THOMAS BEALBY SAUNDERS, of the Firm of Saunders & Saunders, Cleckheaton
in the County of York, Manufacturing Chemists, 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 improvements in or appertaining to the process of coating
iron or steel with zinc commonly called galvanising.
The said process commonly consists in immersing the iron or steel in a bath of
molten zinc protected from the atmosphere by a coat of muriate of ammonia which
salt is thrown on to the bath of metal in small quantities at a time during the working
of said bath. As the heat of the bath of molten zinc partly volatilises the muriate of
ammonia and partly decomposes it into gaseous ammonia it rapidly fumes away, which
fumes have hitherto passed into the atmosphere, therefore being entirely lost, besides
being a source of annoyance to the workmen. My improvements consist in collecting
such volatilised salt and gases passing away from the galvanising bath and recovering
them by condensation.
To carry out my improvements I fit a suitable hood or cover over each bath con-
structed to give the workmen free access thereto but adapted to collect the fumes
passing away from the bath and direct them through a conduit towards a condensing
apparatus where they are dissolved in water or other suitable solvent.

page_text: A draft or current of air artificial or otherwise may be used to assist in directing
the fumes beneath the hood or they may be drawn through the conduit by a pro-
peller. In this manner the fumes from a number of baths may be conveyed to a
common condensing apparatus and recovered.
In order to fully describe my invention reference is made to the accompanying sheet
of drawings forming a part of this specification.
Figure 1 represents a galvanising bath arranged in accordance with my invention
with means for collecting the fumes, arising from the bath, and conveying them to a
condensing tower represented by figure 2. Figure 3 is another arrangement for
condensing the fumes from the bath.
The bath A is covered with a hood B having an opening C at the front to allow
free access to the bath. A pipe D branching from the top of the hood is connected by
a suitable conduit to the pipe or induct D communicating with the interior of the
condensing tower E (commonly termed a
" Glovers Tower") which is of ordinary
construction. The educt or pipe F leading from the tower is in communication with
a chimney or flue so as to create a current or draft in the direction of the arrows
from the hood B through the tower, or if more convenient a propeller or blower may
be introduced at any suitable part of the passage or conduit between the pipe D and
the educt F to create such a current.
In this manner the ammoniacal fumes collected by B are drawn into the tower and
condensed or neutralised by a suitable solvent or acid dropping in the form of spray
from the cistern G at the top of the tower into which it is pumped as required. The
solvent or acid passes from the tower through the opening L into a convenient tank
or reservoir situated at the foot of the tower and is pumped back through the pipe O
into the cistern G until it is approximately saturated with ammonia or the acid
neutralised, when it is drawn away and preferably converted into salts of ammonia.
1 preferably use hydrochloric or sulphuric acid which collects the ammonia in the
form of muriate or sulphate of ammonia. I may employ a series of towers and pass
the fumes consecutively through them when the quantity of fumes requires it.
It is obvious that the form of hood represented in the drawing would not give
sufficient access to the bath to allow all classes of articles to be freely manipulated
during the galvanising process, therefore the hood may be modified in construction
to suit special requirements. As for instance: one or more of the sides may be inde-
pendently adjustable so that it is capable of being raised or lowered or moved to one
side. Or by leaving the pipe D vertical for a suitable length and arranging it to slide
telescopically within or upon another tube the hood may be adjusted vertically as
required, and counter-weights provided to balance it.
The fumes may be passed through the bath H. (figure 3) instead of a condensing
tower, particularly when a propeller or blower is employed to produce a draft. The
fumes from the hood B are forced through the induct a descending into the acid J
and are liberated at K or passed into a second bath, the ammonia being precipitated
in the form of a salt which collects at the lowest point of the bath.
:.
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 :
The combination with a bath for galvanising iron and steel, of a hood for collecting
the fumes from such bath in communication with a condensing apparatus, substantially
as herein shown and described and for the purpose specified.
001
DRACUP & NOWELL,
Bradford, Agents.