IMPROVEMENTS IN GAS OR GAS AND AIR COOKING APPARATUS
Year: 1882

page_text: LETTERS PATENT to James Archibald Slater and Michael Mary Brophy, both
of No. 251, High Holborn, in the County of Middlesex, Engineers, for an
Invention of "IMPROVEMENTS IN GAS OR GAS AND AIR COOKING
APPARATUS."
COMPLETE SPECIFICATION filed by the said James Archibald Slater and
Michael Mary Brophy at the Office of the Commissioners of Patents on
the 10th January 1882.
"
JAMES ARCHIBALD SLATER and MICHAEL MARY BROPHY, both of 251, High
Holborn, in the County of Middlesex, Engineers. IMPROVEMENTS IN GAS OR GAS
AND AIR COOKING APPARATUS."
Our Invention is explained by the accompanying Drawing which shews a half
section and half elevation of a combined baking or roasting oven and hot plate.
A, A, A, are gas and air burners; B, B, B, are the inlets for the air, which is drawn
into the burners by and with the gas; C, C, C, is the gas supply pipe, which is
preferably made of thin copper, but may be made of other suitable material. It
is carried backward and forward across the bottom of the oven in the manner of a
coil so as to get as large a surface as possible exposed to the heat reflected from
the burners; D, D, is a shelf inade of plate iron or other suitable material, and
upon which is placed the bread or other food to be baked or cooked; E, E, E, is
an air jacket surrounding the oven; F is the inlet for fresh air to the air jacket,
and thence into the oven; G is the flue or outlet for the waste gases, the resultants
of combustion; H, H, is the hot plate to be used for boiling, stewing, &c., when
the oven is not required for baking or roasting, &c.; I is the door, which we so
construct that it forms when closed a portion of the air jacket. In some of our
apparatus we make of the door an air-jacket for the front independent of the other
parts. In the combined baking or roasting oven and hot plate, as therein illus-
trated, we balance the door by weights, and make it to slide up and down, so that
when using the hot plate only it may be slid down completely out of the way, and
131

page_text: form a thorough protection for the user of the apparatus from the heat of the
burners.
In present practice, when an air jacket is used, the air is allowed to enter it by
apertures at the bottom, and pass out in some cases by a flue into the chimney,
and in other cases through apertures in the top into the kitchen or other compart-
ment, thereby greatly adding to its discomfort. In neither case is loss of heat by
radiation prevented.
We so construct our apparatus that there is no way for the air required for
combustion to enter it except by the apertures formed for that purpose in the outer
casing of the air jacket at the centre of the top of the apparatus. When the
apparatus is in use the action set up is this, viz.:-The burners being lighted and
the doors closed the air in the chamber beneath the burners is quickly consumed
in combustion with the gas, thereby forming a vacuum, the external atmospheric
pressure acting through the apertures at the top of apparatus forces the air of the
air jacket into the vacuum, and thus is established a current of air downwards
through the air jacket, which continues so long as the burners remain alight. This
current of air in its passage downwards through the air jacket absorbs such heat as
may radiate through the inner casing of the apparatus, and carries it down into
the chamber at the bottom of the oven, and thus the air not only prevents the loss
of heat by radiation through the outer casing of air jacket, and the consequent
overheating of kitchen or other apartment, but is chiefly raised to a high tem-
perature by this heat, which it has thus prevented from going to waste.
this heated air enters the chamber at the bottom of the apparatus it is raised to a
yet higher temperature by the strong heat reflected downwards from the burners.
The gas having to pass through a long length of thin copper made as aforesaid
in the manner of a coil, and placed near the bottom of the apparatus in the strong
reflected heat from the burners, and surrounded by the aforesaid highly heated air,
is also raised to a high temperature before entering the burner for combustion. In
some cases, as, for example, ovens for roasting large quantities of meat, which ovens
are very high, we prefer to place the coil of thin gas pipe around the flue close to
the top of the oven, inside, so that the gas passing through the pipe may be raised
to a high temperature by the waste gases, the resultants of combustion, as they
pass away to the chimney.
When
Having thus described the nature of our Invention, and the manner of working
it, we claim,
Improvements in the construction of gas or gas and air cooking apparatus, such
as will leave no other inlet for the air necessary for combustion, except through
the air jacket, and which improvements secure the raising to a high temperature
the whole of the gas and air used in combustion for the purpose of cooking by
means of heat, which in accordance with present practice is allowed to go to
waste, and this we effect substantially in the manner herein described and
illustrated.
In witness whereof, we, the said James Archibald Slater and Michael
Mary Brophy, have hereunto set our hands and seals, this Tenth day of
Tonaw
T
tha
JAMES A. SLATER.
MICH¹. M. BROPHY. (L.S.)
(L.S.)