IMPROVEMENTS IN THE CONSTRUCTION OF APPARATUS FOR EXTINGUISHING FIRES
Year: 1877

page_text: LETTERS PATENT to William Thomas Dunn, of Manchester, in the County of
Lancaster, for the Invention of "IMPROVEMENTS IN THE CONSTRUCTION OF
APPARATUS FOR EXTINGUISHING FIRES."
Sealed the 7th December 1877, and dated the 11th October 1877.
ແ
PROVISIONAL SPECIFICATION left by the said William Thomas Dunn
at the Office of the Commissioners of Patents on the 11th October 1877.
'IM-
WILLIAM THOMAS DUNN, of Manchester, in the County of Lancaster.
PROVEMENTS IN THE CONSTRUCTION OF APPARATUS FOR EXTINGUISHING FIRES."
This Invention relates to a novel construction of apparatus for extinguishing
fires by carbonic acid gas, and is designed chiefly to be used on board ship or other
confined spaces, but it may also be employed in other suitable places.
The Invention consists of a metal chamber mounted on wheels so as to be capable
of being readily moved about; this chamber is divided into as many compartments
as may be found requisite, but, as an example, I divide it into (say) three
compartments; the middle or largest compartment, which runs from top to
bottom of the chamber, being for receiving the carbonate of lime or other alkaline
solution and muriatic or sulphuric acid, the admixture of which produces a rapid
generation of carbonic acid gas; and two smaller compartments, one on each side of
the larger chamber.
One of these smaller compartments contains two cisterns for holding the muriatic
or sulphuric acid, these cisterns being connected to the larger generating chamber
by means of branch pipes provided with taps for the admission of the acid into the
generating chamber. Underneath these cisterns is a space which may be used as a
store for the supply of acid and whitening, &c.
The other compartment is provided with a force pump near the bottom thereof
for pumping the alkaline solution into the larger or generating chamber. The
upper part of this compartment is for containing the hose, piping, and other appliances
requisite

page_text: The generating chamber is provided with the usual agitator for keeping the
combined mixture of alkaline solution and acid thoroughly roused or agitated.
When it is desired to extinguish a fire, the alkaline solution is forced into the
generating chamber from a convenient receptacle by means of the pump, whilst one
of the taps connected with one or other of the acid cisterns is at the same time
turned on, which allows the acid to flow also into the generating chamber.
When the alkaline and acid combining forms the carbonic acid gas, which passes
out through a suitable opening in the top of the generating chamber to the hose
pipes attached thereto, from whence it is conveyed to the fire which is immediately
extinguished, or if the hold or other compartment of a ship (or other place) be kept
charged with this gas, will prevent, the possibility of a fire arising.
An extra pipe is also provided at the top of each of the acid cisterns, which is
open to the upper part of the alkaline chamber, and allows the pressure of gas
therein to force the acid into the generating chamber; thus as soon as the acid in
one chamber is exhausted, the tap of the other cistern is turned on while the other
is being refilled with acid, and thus a continuous force of carbonic acid is maintained
as long as may be required.
There is also a blow-off tap at the bottom of the alkaline chamber to blow off the
waste or neutralized material contained in the said chamber, so that the engine can
be kept continuously at work till the fire is extinguished.
The generating chamber and the two cisterns are lined with lead to prevent the
action of the acid upon the iron; and suitable gauges are provided both to test the
pressure of the gas in the generating chamber and also to show the height or
quantity of acid in the cisterns.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Thomas Dunn in the Great Seal Patent Office on the 11th
April 1878.
WILLIAM THOMAS DUNN, of Manchester, in the County of Lancaster. "IM-
PROVEMENTS IN THE CONSTRUCTION OF APPARATUS FOR EXTINGUISHING FIRES."
This Invention relates to a novel construction of apparatus for extinguishing
fires by carbonic acid gas, and is designed chiefly to be used on board ship or other
confined spaces, but it may also be employed in other suitable places.
Such being the nature and object of my said Invention, I will proceed to describe
in detail the manner in which the same is to be or may be performed or carried
into practical effect, and in order that the same may be clearly understood I have
annexed hereunto a Sheet of Drawings illustrative thereof, and have marked the
same with figures and letters of reference corresponding with those in the following
explanation thereof.
In the annexed Drawing, Fig. 1 is a longitudinal vertical section; Fig. 2, a trans-
verse section; and Fig. 3, a plan view of my improved apparatus.
The Invention consists of a metal chamber a, a, mounted on wheels b, b, so as
to be capable of being readily moved about; this chamber is divided into as many
compartments as may be found requisite, but, as an example, I divide it into (say)
three compartments c, d, e, the middle or largest compartment d, d, which runs
from top to bottom of the chamber, being for receiving the carbonate of lime or
other alkaline solution and muriatic or sulphuric acid, the admixture of which
produces a rapid generation of carbonic acid gas; and two smaller compartments,
one on each side of the larger chamber.
One of these smaller compartments e, e, contains two cisterns f, f, for holding the
muriatic or sulphuric acid, these cisterns being connected to the larger generating
chamber d, d, by means of branch pipes g, g, provided with taps for the admission
of the acid into the generating chamber. Underneath these cisterns is a space
which may be used as a store for the supply of acid and whitening, &c., or it
may be used for the reception of a pump h, h, composed of an alloy of lead and
antimony (so as to resist acid) for pumping the acid direct from the carboy when
preferred.
The other compartment c, c, is provided with a force pump i, i, near the bottom
thereof, for pumping the alkaline solution from a cask or other vessel into the larger
or generating chamber d, d. The upper part of this compartment may be used for
containing the hose, piping, and other appliances requisite.
The generating chamber d, d, is provided with the usual agitator k, k, for
keeping the combined mixture of alkaline solution and acid thoroughly roused or
agitated.
When it is desired to extinguish a fire, the alkaline solution is forced into the
generating chamber d, d, from a convenient receptacle by means of the pump i, i,
whilst one of the taps connected with one or other of the acid cisterns f, f, is at the
same time turned on, which allows the acid to flow also into the generating chamber,
or the acid is pumped in from the carboy by means of the pump h, h.
When the alkaline and acid combining forms the carbonic acid gas, which passes
out through a suitable opening 1, l, in the top of the generating chamber to the
hose pipes attached thereto, from whence it is conveyed to the fire which is
immediately extinguished, or if the hold or other compartment of a ship (or other
place) be kept charged with this gas will prevent the possibility of a fire arising.
This opening 1, 1, is protected from the froth which arises by means of a wooden
casing m, m, furnished with side openings near the top.
An extra pipe n, n, is also provided at the top of each of the acid cisterns which
is open to the upper part of the generating chamber d, d, and allows the pressure of
gas therein to force the acid into the chamber; thus as soon as the acid in one
I

page_text: chamber ff, is exhausted, the tap of the other cistern is turned on while the other
is being refilled with acid, and thus a continuous force of carbonic acid is maintained
as long as may be required.
There is also a blow-off o, o, at the bottom of the alkaline chamber to blow off
the waste or neutralized material contained in the said chamber, so that the
engine can be kept continuously at work till the fire is extinguished.
The generating chamber d, d; and the two cisterns f, f, are lined with lead to
prevent the action of the acid upon the iron, and suitable gauges p, p, are pro-
vided both to test the pressure of the gas in the generating chamber and also to
show the height or quantity of acid in the cistern.
Having now described the nature and object of my said Invention, together with
the manner in which the same is to be or may be performed or carried into practical
effect, I wish it to be understood that I claim as my Invention the novel con-
struction of portable apparatus for extinguishing fires by means of carbonic acid
gas, substantially as herein-before described and illustrated by the Drawings
annexed.
In witness whereof, I, the said William Thomas Dunn, have hereunto set my
hand and seal, this Ninth day of April, in the year of our Lord One
thousand eight hundred and seventy-eight.