IMPROVEMENTS IN OVENS AND APPARATUS FOR BAKING
Year: 1852

page_text: LETTERS PATENT to William Slater, of Carlisle, in the County of
Cumberland, for the Invention of "IMPROVEMENTS IN OVENS AND
APPARATUS FOR BAKING."
Sealed the 20th May 1853, and dated the 1st December 1852.
PROVISIONAL SPECIFICATION left by the said William Slater
at the Office of the Commissioners of Patents, with his Peti-
tion, on the 1st December 1852.
I, WILLIAM SLATER, of Carlisle, in the County of Cumberland, do
hereby declare the nature of the said Invention for "IMPROVEMENTS
IN OVENS AND APPARATUS FOR BAKING" to be as follows:
-
This Invention relates to the baking of biscuits, bread, and other
articles, by traversing such articles along and through a heated tube
of earthenware. This tube forins the oven; it is of considerable
length; and the biscuits or other articles are slowly traversed
through it, from end to end, at such rate as will allow of the
baking being completed during the passage. The biscuits are carried
or trays set on travelling chains, or the trays may be made into an
endless web or chain. The oven is thus entirely self-acting, and the

page_text: baking articles demand no attention whatever from the attendants,
whilst the system involves superior economy and better baking.
There is also an apparatus attached externally for at all times indi-
cating the internal heat of the oven-enabling the attendant to
adapt it to all the purposes required.
SPECIFICATION in pursuance of the conditions of the Letters
Patent, filed by the said William Slater in the Great Seal
Patent Office on the 31st May 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
WILLIAM SLATER, of Carlisle, in the County of Cumberland, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the. First day of December, in the
year of our Lord One thousand eight hundred and fifty-two, in
the sixteenth year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said William Slater,
Her special license that I, the said William Slater, my executors,
administrators, and assigns, or such others as I, the said William
Slater, my executors, administrators, 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, use, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and Isle
of Man, an Invention for "IMPROVEMENTS IN OVENS AND APPARATUS
FOR BAKING," upon the condition (amongst others) that I, the said
William Slater, by an instrument in writing under my hand and
scal, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same was to be per-
formed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the
date of the said Letters Patent.
NOW KNOW YE, that I, the said William Slater, do hereby
declare the nature of my said Invention, and in what manner the

page_text: same is to performed, to be particularly described and ascertained
in and by the following statement; reference being had to the ac-
companying Drawings, and to the letters and figures marked
thercon (that is to say):
My said Invention relates to the baking of biscuits, bread, and
other articles, by traversing such articles along and through a
heated tube of earthenware. This tube forms the oven; it is of
considerable length; and the biscuits or other articles are slowly
traversed through it, from end to end, at such a rate as will allow
of the baking being completed during the passage. The biscuits
are carried on trays set on travelling chains, or the trays may be
made into an endless web or chain. The oven is thus entirely self-
acting, and the baking articles demand no attention whatever from
the attendants, whilst the system involves superior economy and
better baking. A pyrometer, or heat indicator, is also attached
externally, so that the attendant can regulate the heat with very
great facility. The object of such improvements is to reduce the
cost of baking, and to improve the appearance of the baked articles;
and the apparatus, or modifications thereof, is applicable as well to
the baking of clay or carthenware articles, as to bread or biscuits.
Figure 1, on my Sheet of Drawings, is a vertical longitudinal
section of my improved oven, as more especially contrived for baking
biscuits; Figure 2, is a transverse section of the oven; and Figure 3,
is an external face elevation of the iron mouth piece or door, with
its pyrometer attached. The earthenware baking tube or retort A,
which is the actual baking chamber, is shaped somewhat like a gas
retort, and is of considerable length; from 16 to 24 feet being the
length which I find convenient and effective. This tube is set in
brickwork, like a steam boiler, and it is heated by the furnace B,
which is supplied with fuel in the usual way through the door C.
The direct radiant heat of the fuel is received by the over head
brick or clay arch D, and the heat and gases pass off from the
grate along the bottom flue C, in the direction of the arrow running
hence along beneath the tube A. At E, E, are side or lateral
passages, branching off from the furnace and main bottom flue into

page_text: the side and over head flues F, G, between the outside of the clay
tube A, and the interior of its surrounding mass of brickwork; so
that the tube A, is thus completely enveloped in a heated medium.
After traversing all the flue lengths, the heated current finally
passes off through the chimney II. The baking tube is open from
end to end, and is covered in at these entrances by iron plates I,
slotted through to admit the endless carrying band or chain J, to
pass through. This band or chain is carried upon two external
rollers or pulleys K, set at the required level, outside the tube A;
both the upper and lower lengths of the chain being passed
right through the whole length of the tube, and supported therein
by an upper and lower line of bearing rollers L. This carrying
chain may be formed in various ways. It may either be composed
of two parallel endless chains, with carrying trays laid across, or of
a scries of trays so connected as to form an endless chain, or an
endless web of wire cloth. One of the pulleys K, being inade to
revolve at the required rate by means of any convenient prime
mover, the chain, with the biscuits or articles to be baked laid on,
is traversed through the tube at the required rate; the unbaked
articles being deposited upon the chain at one end, and carried
directly through and out at the other; the speed of movement being
proportioned so that the articles shall be baked to the required
extent in the transit. The baking heat is, of course, derived from
all sides of the heated tube A, and this heating power is capable of
nice regulation, by means of dampers suitably disposed in the flues.
The pyrometer, or heat indicator, consists of a copper or other
metal rod M, stretched along the upper side of the tube. It is fixed
at the back end N; but its other end O, is loose, and passes freely
through the plate I, at that end. There it is connected to a stout
helical spring, contained in the box P, and contrived so as to hold
the rod M, in a high state of tension; the spring being protected
from the heat by the box, which is lined with loam or sand, or is
made of baked wood. The end of the rod has a transverse pin
attached to it; and this pin works through a longitudinal slot in

page_text: the box being made to act upon an arrangement of multiplying
levers Q, terminating in an index hand R, pointing to the degrees
of temperature marked upon the outside of the plate I. In this
way, the expansion and contraction of the rod M, points out the
variations in the temperature, by the corresponding movements of
the hand over its indicating scale. To support the rod M, pendant
links are either hung froin the roof of the oven, or two other metal
rods are passed through the oven, a few inches apart, in a parallel
line; such rods having a series of cross bearers, at intervals, capable
of movement upon the longitudinal rods. The latter are fixed by
one end, and moveable at the other, like the rod M. In marking the
heat graduations on the scale, the details are first set up, and the
position of the index hand is then marked off, whilst the oven is
cold, the temperature of the oven being taken by a thermometer.
This is the zero of the indicator. The heat is then brought up, and
the temperature is again marked as before; the rest of the gradua-
tions being marked in the usual inanner of marking thermometric
scales.
Having now described and particularly ascertained the nature of
my said Invention, and the manner in which the same is or may be
used or carried into effect, I would observe, in conclusion, that I do
not confine or restrict myself to the precise details or arrangements,
which I have had occasion to describe or refer to, as many variations
may be made therefrom without deviating from the principles or
inain features of my Invention; but what I consider to be novel
and original, and therefore claim as the Invention secured to me by
the herein-before in part recited Letters Patent, is,-
First, the general arrangement and construction of ovens or
baking apparatus, as herein-before described.
Second, the system or mode of baking biscuits and other ar-
ticles, by traversing the same through a clay or earthenware tube,
or baking chamber.
Third, the application and use of clay or carthenware baking
tubes or chambers, for baking biscuits and other articles.

page_text: Fourth, the application and use of a pyrometer, or heat indi-
cator, in the manner and for the purposes herein-before described.
In witness whereof, I, the said William Slater, have hereunto
set my hand and seal, the Twenty-seventh day of May,
One thousand eight hundred and fifty-three.
WILLIAM SLATER. (L.S.)