" IN THE PRODUCTION OF SULPHUROUS ACID.OR SALTS OR SOLUTIONS CON- TAINING SULPHUROUS ACID AND IN THE MODE OF APPLYING THE SAME TO THE TREATMENT OF WOOD PULP AND OTHER PURPOSES "
Year: 1883

page_text: LETTERS PATENT to Isaac Shimwell McDougall of Irk Vale Chadderton near
Manchester in the County of Lancaster for an Invention of IMPROVEMENTS
"
IN THE PRODUCTION OF SULPHUROUS ACID.OR SALTS OR SOLUTIONS CON-
TAINING SULPHUROUS ACID AND IN THE MODE OF APPLYING THE SAME TO
THE TREATMENT OF WOOD PULP AND OTHER PURPOSES
"
PROVISIONAL SPECIFICATION left by the said Isaac Shimwell M°Dougall
at the Office of the Commissioners of Patents on the 13th March 1883.
ISAAC SHIMWELL MCDOUGALL of Irk Vale Chadderton near Manchester in the
County of Lancaster " IMPROVEMENTS IN THE PRODUCTION OF SULPHUROUS
ACID OR SALTS OR SOLUTIONS CONTAINING SULPHUROUS ACID AND IN THE MODE
OF APPLYING THE SAME TO THE TREATMENT OF WOOD PULP AND OTHER
PURPOSES"
Solutions of Sulphurous Acid and sulphites and bisulphites of alkaline earths,
have been produced to be employed in the production of pulp, by burning sulphur
compounds with the oxygen of the air and conducting the sulphurous acid gas.
produced upwards through a tower or vertical column containing suitable material
to diffuse the gas, where it is brought into contact with water or alkaline solutions
passing down over the diffusing material-This means of production is inconvenient,
as in such towers it is difficult to condense the whole of the gas, or to produce
solutions of regular strength, and considerable nuisance is sometimes caused by the
escape of gases
By means of my improvements I produce sulphurous acid or solutions. containing
sulphurous acid or sulphite or bisulphite or other solutions or other salts without
employing condensing towers or columns.
I accomplish this by burning sulphur, or pyrites, or spent oxide of iron, or other
suitable sulphur compounds in strong enclosed vessels, into which after igniting

page_text: the sulphur or its compounds I force air by any suitable mechanical means, such
as an air pump or fan, of sufficient power to drive the sulphurous acid gas through
suitable pipes or connexions direct into the vessel or series of vessels, with suitable
connexions, containing the wood or other fibrous matter and with or without
alkalies or alkaline earths, or I drive the sulphurous acid gas into other suitable
vessels containing the water or solutions or alkalies or alkaline earths with which
it is desired the gas shall be brought into contact for the purpose of obtaining
products containing sulphurous acid-Complete control is thus maintained over
the sulphurous acid gas, and this gas or solutions of it or sulphite or bisulphite
solutions or other salts or mixtures of them may be prepared of any strengths and
in any quantities desired for employment in the treatment of Pulp or for other
purposes

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Isaac Shimwell McDougall in the Great Seal Patent Office
on the 13th September 1883.
ISAAC SHIMWELL MCDOUGALL of Irk Vale Chadderton near Manchester in the
County of Lancaster "IMPROVEMENTS IN THE PRODUCTION OF SULPHUROUS
ACID OR SALTS OR SOLUTIONS CONTAINING SULPHUROUS ACID AND IN THE MODE
OF APPLYING THE SAME TO THE TREATMENT OF WOOD PULP AND OTHER
PURPOSES'
"
Solutions of sulphurous acid and sulphites and bisulphites of Alkaline earths
have been produced to be employed in the production of paper pulp by burning
sulphur compounds with the oxygen of the air and conducting the sulphurous acid
gas produced, upwards through a tower or vertical column containing suitable
material to diffuse the gas where it is brought into contact with water or alkaline
solutions passing down over the diffusing material. This means of production is
inconvenient as in such towers it is difficult to condense the whole of the gas or
to produce solutions of regular strength, and considerable nuisance is sometimes
caused by the escape of gases.
By means of my improvements I produce sulphurous acids or solutions containing
sulphurous acid or sulphite or bisulphite or other solutions or other salts without
employing condensing towers or columns
I accomplish this by burning sulphur or pyrites or spent oxide of iron or other
suitable sulphur compounds in strong enclosed Vessels, into which after igniting
the sulphur or its compounds, I force air by any suitable mechanical means such
as an air pump or fan of sufficient power to drive the sulphurous acid gas through
suitable pipes or connections, into a vessel or series of vessels containing water or
solutions or alkalies or alkaline earths with which it is desired the gas shall be
brought into contact for the purpose of obtaining products containing sulphurous
acid. Or where preferable I force the air or gas forward by suction by suitably
placing the air pump or fan for that purpose
Also where preferable I surround with water the vessel or vessels in which the
sulphur is burned and the pipes or connections carrying the sulphurous gas, for
the purpose of reducing the temperature of same. Complete control is thus
maintained over the sulphurous acid gas. and this gas or solutions of it, or sulphite
or bisulphite solutions, or other salts or mixtures of them, may be prepared of any
strengths and in any quantities desired for employment in the treatment of pulp
or for other purposes.
Having now described and particularly ascertained the nature of my said
Invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and original
and therefore claim as the Invention secured to me. by the hereinbefore in part
recited Letters Patent is :-
The production of sulphurous acid or solutions containing sulphurous acid or
sulphite or other salts without the use of condensing towers or columns in the
manner and for the purposes bereinbefore described.
In witness whereof I the said Isaac Shimwell McDougall have to this my
Specification set my hand and seal this tenth day of September One thousand
eight hundred and eighty three.