IMPROVEMENTS IN PORTABLE OVENS FOR BAKING BREAD AND OTHER ALIMENTS
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by John Henry Johnson at the Office
-
of the Commissioners of Patents on the 10th July 1883. Communicated to
him from Leon Dathis a person resident at Paris in the Republic of France,
Civil Engineer
s
JOHN HENRY JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex,
Gentleman,' IMPROVEMENTS IN PORTABLE OVENS FOR BAKING BREAD AND
OTHER ALIMENTS" A communication to me from Leon Dathis a person resident at
Paris in the Republic of France Civil Engineer
This Invention relating to portable ovens consists in the employment as herein-
after described of means for concentrating regulating and distributing the heat so
as to cause it to act in a most effectual and economical manner upon the articles
that are to be baked
In carrying out this invention the heat is regulated and distributed equally over
the articles to be baked by means of a special arrangement of deflecting and
radiating plates and reflecting or reverberating surfaces arranged as hereinafter
described.
A dome shaped chamber or bell, preferably of sheet iron and covered with heat
retaining materials is placed upon a metal plate forming the bottom of the oven
and whose under surface is exposed to heat generated in a furnace or fire place of
any suitable description. The articles to be baked are suspended from or arranged
upon a suitable support such as a tray or trays supported at a suitable height in
the interior of the chamber by racks or brackets whereby the position of the said
trays is enabled to be adjusted as required. Interposed between these trays and
the plate hereinbefore referred to are arranged one or more adjustable deflecting
plates or discs supported in a similar manner to the trays or otherwise and
preferably slightly dished having the convex side downwards.
These deflecting discs as well as the trays supporting the articles to be baked
are of less diameter than the interior of the chamber so as to form an annular.
passage between the inner surface of the chamber and the edges of the said plates
and trays. The sides of the plate forming the bottom of the chamber are preferably
turned up so as to fit into or surround the vertical sides of the chamber so that the
height and internal capacity of the latter may be adjusted by sliding it telescopically
upon the sides or edges of the said plate. The roof of the dome shaped chamber
I Prine 71

page_text: is provided with windows of mica or equivalent material through which the
progress of the baking may be watched and also with a thermometer for indicating
the internal temperature.
The heat radiated from the upper side of the plate forming the bottom of the
oven impinges against the plate or plates interposed between the tray supporting
the articles to be baked and the bottom of the oven and a portion of the heat is
thereby deflected and caused to pass upwards through the annular passage between
the edges of the deflecting plates and the tray. The heat thus deflected ascends
to the roof of the chamber whence it is reverberated on to the upper side of the
articles on the tray whilst the remainder of the heat is transmitted directly through
the deflecting plates to the under side of the tray and acts upon the underside of
the articles placed thereon.
By means of this arrangement the heat is concentrated upon and uniformly
distributed over the articles to be baked and may be controlled or regulated with
the utmost precision by simply adjusting the positions of the deflecting plates and
of the trays or supports hereinbefore described and by increasing or diminishing
the area of the annular passage.