Improvements in Covering Lead Surfaces to Protect Water and other Liquids from Contamination with the Dissolved Metal.
Year: 1891

page_text: Date of Application, 25th May, 1891
Complete Specification Left, 23rd Feb., 1892-Accepted, 14th May, 1892
PROVISIONAL SPECIFICATION.
Improvements in Covering Lead Surfaces to Protect Water
and other Liquids from Contamination with the Dissolved
Metal.
ALEXANDER MCDOUGALL Retired Chemist 17 Belmont Street Southport do
hereby declare the nature of this invention to be as follows:-
It is well known that certain waters and other liquids act upon lead and dissolve
30 much of it as to render them wholesome for drinking or for use in cooking
food..
My invention consists in coating lead surfaces with a covering impervious to air,
water or such acids as are found in potable waters, and thus protecting them from
contamination by dissolved lead.
In carrying out my invention I take nitro-cellulose and dissolve it in alcohol and
ether or mythelated spirits, and add castor oil and Canada balsam to the solution
to obtain a flexible collodion. When a product of greater consistency is required
I add a proportion of strontia or magnesia or compounds thereof and then apply
the preparation to the surface of the lead to protect water & other liquids from
contamination by coming into contact with the dissolved lead.
A. MCDOUGALL.
COMPLETE SPECIFICATION.
Improvements in Covering Lead Surfaces to Protect Water
and other Liquids from Contamination with the Dissolved
Metal.
ALEXANDER MCDOUGALL Retired Chemist 17 Belmont Street Southport 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:-
It is well known that certain waters and other liquids act upon lead and dissolve
so much of it as to render them unwholesome for drinking or for use in cooking
food.
My invention consists in coating lead surfaces with a covering impervious to air
water or such acids as are found in potable waters and thus protecting them from
contamination by dissolved lead.
In carrying out my invention 1 take nitro-cellulose and dissolve it in alcohol and
ether and add about two per cent. of castor oil or Canada balsam to the solution
to obtain a flexible collodion. When a collodion of greater consistency is required
I add a proportion of strontia or magnesia or compounds thereof in quantities
varying from two to eight per cent., the larger proportion being used on extended
surfaces, the lesser on the internal surfaces of pipes. Of these compounds I prefer
to use magnesium silicate.
This preparation I apply to the surface of the lead to protect water &c. from
contamination by coming into contact with the lead.
In the case of sheet lead the solution is applied to the surface with a brush, or
other convenient implement, and the sheet so covered is exposed to effect the
evaporation of the volatile solvent, which leaves a thin covering of flexible collodion
on the surface of the lead. This operation is to be repeated till the covering
is of the desired thickness. Two or three such coatings are usually found to be
sufficient

page_text: In the case of its application to lead pipes the solution is poured into the open
end to fill the pipe and is allowed to remain till a sufficient coating of collodion is
deposited on the interior surface of the pipe, when the excess of the solution is
drained off. The period during which the solution must be retained in the pipe
will vary with the temperature of the atmosphere, if it be low a longer time will
be required.
Having now particularly described & ascertained the nature of my inven-
tion and in what manner the same is to be performed 1 declare that what I
claim is
1. The application of a flexible collodion to lead surfaces to prevent the con-
tamination of water or other liquids by contact with the lead.
II. The use of a volatile solvent to effect the deposition of the flexible collodion
on the lead surfaces.
Dated this Twenty-second day of February 1892.
A. MCDOUGALL.