Improvements in Portable Terra-cotta Stoves.
Year: 1893

page_text: Date of Application, 16th Mar., 1893-Accepted, 24th June, 1893
COMPLETE SPECIFICATION.
Improvements in Portable Terra-cotta Stoves.
I THOMAS ROBERTS of 34 Victoria Street, Westminster in the County of
Middlesex, Stove Manufacturer, 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 alterations and improvements in stoves constructed of
terra-cotta either in solid or granulated form, contained between concentric
cylinders of sheet iron or other metal, the outer cylinder being perforated to
permit direct radiation of heat from the terra-cotta; and known in the trade as
Roberts's Patent Portable Terra Cotta Stoves" dated 12th May 1887 No. 6977.
It is found in practice that when from carelessness or other cause a stove becomes
overheated through neglect in controlling excessive draught its lining cylinders
expand and bulge inwards, and the terra cotta falls into the spaces made by this
bulging and, remaining there prevents the metal when cool from contracting to
its original shape thus leaving insufficient room for the proper adjustment of the
fire box.
This invention is intended to overcome the above difficulty by a new structural
improvement which I propose to effect by abandoning the method of construction
hitherto employed, by which the two lining cylinders and the outer cylinder
forming the stoor-body are fastened together at the top and bottom only, and
completely uniting the inner and outer cylinders and the terra-cotta in one compact
whole by bolts or screws passed through them and firmly fixed by nuts, or riveted,
or secured by any other means that may be preferred; the bolts or screws being
distributed more or less over the whole surface of the stove body thus affording the
greatest possible resistance to expansion and compelling the inner or lining cylinder
to retain nearly its normal shape.
And in order that my said invention may be fully understood I will refer to the
drawings accompanying this Specification in which
Fig. 1 shews view of stove partly in section and Figs. 2 and 3 shew bottom of
fire box hereafter referred to.
Same letters denote the same parts in all the views.
a shews the outer cylinder of stove, binner one, a terra cotta between the two
cylinders, d. shews bolts passing through the two cylinders and terra cotta so as to
hold the whole firmly together and prevent bulging of the inner cylinder 6 from
excessive heat.
Concurrently with the foregoing improvement I propose to effect a further one
by an alteration in the base of the fire box of the stove providing means for
increasing when necessary the draught passing immediately through the fuel in
order that as the latter varies widely in its combustible quality the stove shall be
rendered available for the least combustible or any other kind of fuel and this I
propose to accomplish as follows:-
In addition to the ordinary number of perforations or openings, which are
generally sufficient for the passage of air, I make between or near them a number
of others, over which I fix preferably with wire or by other method a metal disc or
plate to close them but so arranged as to be easily removeable on emergency when
the fuel used is of such a kind as to necessitate a stronger draught.
This will be understood on reference to Figs. 2 and 3, Fig. 2 shews the ordinary
base with the extra holes e (shewn at Fig. 3) covered by the disc f, this disc is
secured by pieces of wire g, passing through the base h. so that when it is desired
to increase the draught it is simply necessary to cut the wires g. when the disc f.
will fall off and leave the base as shewn in Fig. 3. with all the holes e. exposed,

page_text: 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 :-
1. In portable terra cotta stoves the addition of bolts or screws d. passing
through the cylinders and the terra cotta and fastened to unite them in one compact
whole.
2. The addition of a disc or plate to the base of the fire box in combination with
extra holes substantially as and for the purposes set forth.
Dated this 16th day of March 1893.
BROWNE & Co.,
9, Warwick Court, W.C., Agents for Applicant.