IMPROVEMENTS IN BAKE OVENS
Year: 1875

page_text: LETTERS PATENT to Peter Jensen, of Chancery Lane, London, for
the Invention of "IMPROVEMENTS IN BAKE OVENS."-A communication
from abroad by Philipp Dührkop, of Altona, in the Gorman
Empire.
Sealed the 9th July 1875, and dated the 11th March 1875.
PROVISIONAL SPECIFICATION left by the said Peter Jensen at tho
Offico of the Commissioners of Patents, with his Petition, on the
11th March 1875.
I, PETER JENSEN, of Chancery Lanc, London, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN BAKE OVENS," (a
communication to me from abroad by Philipp Dührkop, of Altona, in
the German Empire,) to be as follows:-
The object of this Invention is to construct bake ovens for constant
work and full utilization of the fuel, the heating of the top and bottom
being easily regulated as required.
The white bread bake oven constructed according to this Invention is
mainly distinguished from the rye bread bake oven according to this

page_text: Invention by the application in the former of a layer of sand under the
oven bottom, which layer is heated by the flame and gases; in the latter
however the flame and gases strike directly against the oven bottom;
the arrangement of the flues, dampers, and furnace is otherwise the same
in both.
The flame and heat from the grate pass through a flue or flues to tho
back of the oven, which flue may be slightly increasing in height
towards the back and have a flat arched top; the flame and heat then
return through a series of flues arranged over the said arched top, which
flues are situated under the sand layer under the oven bottom, and may
be gradually increasing in height towards the front, where they terminate
into flues leading off right and left to an ascending flue on each outer
side of the oven, the said ascending flues communicating with flues
passing to the back over the oven top at each side, and then returning
to the front in the middle, whence the remaining heat and gases or
flamo are led to the chimney. Communicating flues are arranged
between the aforesaid ascending flues on cach side and the first fluc
proceeding backwards from the grate; a damper is arranged at cach
side, and when these dampers are shut the flame and heat travel on as
described, but if they are open the flame and heat would pass off into
the said ascending flues at once, and thence along the top of oven
without imparting direct heat to the sand layer under the oven bottom.
The bake oven itself is closed by doors; soot doors are provided for
the flues; sight holes for observation, and, if desired, insertion of
pyrometer are also provided; and a boiler for providing steam may be
arranged in the brickwork.
As the flame and heated gases do not come in direct contact with the
things to be baked any fuel may be used. The sand layer distributes
the heat evenly, thus preventing undue heat anywhere. Once hot the
oven requires very little firing to keep it hot, and it does not cool down
quickly as it is surrounded by brickwork and the air in the flues
prevents loss of heat, the flues being long enough to produce the
maximum utilization of the fuel.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Peter Jensen in the Great Seal Patent Office on
the 11th September 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, PETER
JENSEN, of Chancery Lane, London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eleventh day of March, in the year
of our Lord One thousand eight hundred and seventy-five, in the
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Peter Jensen, Her special
licence that I, the said Peter Jensen, my executors, administrators, and
assigns, or such others as I, the said Peter Jensen, my executors, admi-
nistrators, and assigns, should at any time agree with, and no others,
from time to time and at all times thereafter during the term therein
expressed, should and lawfully might make, usc, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, tho Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN BAKE
OVENS," (a communication to mo from abroad by Philipp Dührkop, of
Altona, in the German Empire,) upon the condition (amongst others).
that I, the said Peter Jensen, my executors or administrators, by an
instrument in writing under my, or their, or one of their hands and
scals, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Scal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, tho said Peter Jensen, do hereby declare the
nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement, reference being had to the accompanying Drawings,
and to the letters of reference marked thereon, that is to say:—
The object of this Invention is to construct bake ovens for constant
work and full utilization of the fuel, the heating of the top and bottom
being easily regulated as required.
An oven for white bread baking constructed according to this Inven-
tion is. represented on Sheet 1 by Figures 1 to 7, Fig. 1 being a front

page_text: clevation; Fig. 2, a longitudinal section; Fig. 3, a sectional plan showing
the heating surface; and Fig. 4, a vertical section through A, B, Fig. 3;
Fig. 4, a vertical section through C, D, Fig. 3; Fig. 5 is a sectional
plan showing the flues under the oven floor; Fig. 6, a sectional plan
showing the flues over the oven top; and Fig. 7, a sectional plan of the
oven floor.
An oven for rye bread baking constructed according to this Invention
is represented on Sheet 2 by Figures 8 to 14. Fig. 8 being a front
elevation; Fig. 9, a longitudinal section; Fig. 10, a sectional plan
showing the heating surface; and Fig. 11, a vertical section through
A, B, Fig. 10; Fig. 12 is a sectional plan showing the flues under the
oven floor; Fig. 13 a sectional plan showing the flues over the oven
top; and Fig. 14 a sectional plan of the oven floor.
. The white bread bake oven constructed according to this Invention
is mainly distinguished from the rye bread bake oven .constructed]
according to this Invention by the application in the former of a layer
of sand under the oven bottom, which layer is heated by the flame and
gases; in the latter however the flame and gases strike directly against
the oven bottom. The arrangement of the flues, dampers, and furnace
is otherwise the same in both. b is the firc-grate on which the fuel is
placed..
The flame and heat from the grate pass through a flue or flues A to
the back of the oven, which flue A may be slightly increasing in height
towards the back and have a flat arched top, as shown; the flame and
heat then return through a series of flues B arranged over the said
arched top, which flues are situated under the sand layer C under the
oven bottom D, and may be gradually increasing in height towards the
front, where they terminate into flues J leading off right and left to an
ascending flue H on each outer side of the oven, the said ascending flues
communicating with a flue or flues E passing to the back over the oven
top at each side and then returning by a flue or flues E¹ to the front in
the middle, whence the remaining heat and gases or flame are led to the
chimney S by flues F. Communicating flues are arranged between the
aforesaid ascending flues H on each side and the first flue A proceeding
backwards from the grate, and dampers and glare arranged at each
side for concentrating the heat on the bottom or top of the oven. When
the dampers are shut the flame and heat travel on as described, but if

page_text: the bottom heat is too strong, or if a greater top heat be desired, g,g,
are opened and 9', 9', shut, the flame and heat will then pass off into the
said ascending, flues H at once and thence along the top of oven without
imparting direct heat to the sand layer under the oven bottom.
The bake oven itself is closed by doors c; f, f, are soot doors for the
flues E; sight holes for observation and, if desired, for insertion of
pyrometer are also provided; and a boiler for providing steam may be
arranged in the brickwork.
As the flame and heated gases do not come in direct contact with the
things to be baked any fuel may be used. The sand layer C in the
white bread oven distributes the heat evenly, thus preventing. undue
heat anywhere. Once hot the oven requires very little firing to keep it
hot, and it does not cool down quickly as it is surrounded by brickwork
and the air in the flues prevents loss of heat, the flues being long enough-
to produce the maximum utilization of the fuel. These ovens answer
exceedingly well in practice.
And having thus fully ascertained and described the nature of this
Invention I declare that I claim as the Invention,―
Firstly. The general arrangement and combination of flues sub-
stantially as and for the purposes set forth.
And, Secondly. The application of the layer of sand under the oven
bottom in bake ovens, arranged substantially as here set. forth.
In witness whereof, I, the said Peter Jensen, have hereunto set
my hand and seal, this Tenth day of September, in the year of
our Lord One thousand eight hundred and seventy-five.