CERTAIN IMPROVED MACHINERY AND PROCESSES FOR ECONOMISING AND PURIFYING THE MANUFACTURE OF BREAD, A PART OF WHICH IS APPLICABLE TO OTHER PURPOSES
Year: 1836

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, LUKE
HEBERT, of Paternoster Row, in the City of London, Patent Agent, send
greeting.
WHEREAS His present most Excellent Majesty King William the Fourth,
by is Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Second day of June, in the sixth year of His reign did,
for Himself, His heirs and assigns, give and grant unto me, the said Luke
Hebert, His especial licence, full power, sole privilege and authority, that I,
the said Luke Hebert, my exors, adiñors, and assigns, or such others as
I, the said Luke Hebert, my exors, adññors, or assigns, should at any time
agree with, and no others, from time to time and at all times during the term
of years therein expressed should and lawfully might make, use, exercise, and
vend, within England, Wales, and the Town of Berwick-upon-Tweed, and also
in all His said Majesty's Colonies and Plantations abroad, the Invention of
"CERTAIN IMPROVED MACHINERY AND PROCESSES FOR ECONOMISING AND PURIFYING
THE MANUFACTURE OF BREAD, A PART OF WHICH IS APPLICABLE TO OTHER PURPOSES,"
(partly communicated to me by a certain foreigner residing abroad;) in which
said Letters Patent is contained a proviso that I, the said Luke Hebert,
shall cause a particular description of, the nature of the said Invention, and
in what manner the same is to be performed, to be inrolled in His said
Majesty's High Court of Chancery within six calendar months next and
immediately after the date of the said in part recited Letters Patent, as
in and by the same, reference being thereunto had, will more fully and at
large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Luke Hebert, do hereby declare that the nature of my said Invention, an

page_text: the manner in which the same is to be performed, is herein-after fully
explained; but in order that the objects sought for may be the better appre-
ciated, I will make a few preliminary remarks:-
Bread forming the chief sustenance of the inhabitants of nearly the whole of
the civilized world, it is consequently a manufacture far surpassing all others
in extent. Hitherto, however, it has not been treated as a manufacture; the
homely and unscientific practices of past ages remain in all their pristine
impurity and wastefulness; to please the eye, the most nutritive and agreeable
properties of the wheat are partially destroyed or deteriorated. To economize
and purify the "staff of life" appears to have been an object either unworthy of
the attention or degrading to the study of philosophers and mechanics, while
that of a candlewick, and numerous other "trifles light as air," have been the
objects of much elaborate investigation and public patronage. It is, never-
theless, a fact capable of demonstration, that the present system of supplying
the public with bread is equivalent to an unnecessary tax upon the people of
these kingdoms of fifteen millions sterling annually. The whole of this
enormous sum is swallowed up in wasteful processes and needless commercial
operations. Extraordinary as this statement may appear at first sight, its
truth will be apparent after a little consideration. By the improved mechanism
and processes herein described the wheat is introduced to the top floor of the
manufactory, it then passes through the several processes of washing, purifying,
drying, cleaning, grinding, dressing, preparing the dough, weighing, moulding,
baking, and delivering, all of theso processes (the moulding excepted) being
performed by machinery in the short space of three hours. It is useless to
contrast this rapid mode of converting wheat into bread (and money) with the
present system of "aging the meal," "aging the flour," carriage, sacks, waste,
capital, intermediate dealers, fermentation, and numerous other charges which
the concentration of the processes just described entirely supersedes.
Before proceeding to describe the details of my manufactory, by which the
concentration of those processes is effected, I will, for the more ready com-
prehension of the reader, first explain its main characteristics by giving a
brief outline of my mode of operating, from the reception of the grain to the
baking of the bread. The grain is delivered into the receiving room of
the manufactury, here it is examined and weighed, and then shot into the
hopper of the double wheat elevator, by which it is carried up to the top of
the building, and delivered on to a creeper that conducts it to any part of the
several garners. The trunk of this elevator is supplied with warm air. As
the grain is required for the purposes of the manufacture it is permitted to run
down into the cleaning and drying room, for the purpose of being sifted,

page_text: screened, and prepared; hence it descends into the cooling and grinding
garners. Should any of the grain be in too impure a state to admit of being
cleansed by the dry process already mentioned, it is conducted from its garner
into the washing room, where it is purified by scouring and sifting in water,
after which it descends into a warm air chamber, where it is kept constantly
in motion until sufficiently dried to be also delivered into the grinding garners,
which are situated over the mills and dressing apparatus. Into these machines
the grain is delivered, ground, and dressed, the flour being raised by elevators
into the flour garners, and the offals delivered into sacks. For converting the
flour into bread it is first well mixed with the requisite quantity of finely
ground salt, and then put into hoppers, which serve the twofold purpose
of measuring the quantity and conducting it into the mixing and kneading
apparatus. This department of the manufacture is not conducted in the
ordinary manner, as the wasteful, tedious, and uncertain process of fermen-
tation is entirely superseded by the immediate and direct application to the
flour of water highly impregnated with carbonic acid gas and atmospheric air.
The impregnation and kneading being quickly completed, the dough is made
to descend an inclined plane on to a long table, where it is weighed and
moulded, thence it descends another inclined plane on to a "making-up table,"
situated on the charging and discharging apparatus of the ovens. As fast as
the loaves are made up they are placed upon a heated cast-iron pan, which
gradually advances into the oven until the pan becomes filled and the oven
completely charged. The ovens consist of a vertical tier or series of low
rectangular chambers, and the charging and discharging apparatus is employed
successively upon each of them by raising or lowering the apparatus, which is
provided with simple mechanism to effect those operations with facility and
dispatch, to prevent the wasteful and injurious effects of burning the bread on
the one hand, and the liability of a deficiency of heat on the other. The
medium by which these ovens are heated is steam or hot water, and the vapour
arising from the bread is retained under a slight pressure, by which a regular
and constant heat indispensable to good baking is always insured.
I now proceed to describe more in detail the entire arrangement or combina-
tion of mechanism whereby I economize and purify the manufacture of bread,
"with reference to the Drawings hereunto annexed and marked." Figures
A, B, C, D, E, F, G, H, in.all of which the same numerals are used to denote
the same objects or parts, however differently viewed. These Figures exhibit
plans, elevations, and sections of the various parts of my said manufactory, all
of which Figures are drawn to the scale of parts marked thereon. Figure A
exbibits a general plan of the whole building and premises, with the various

page_text: plant and mechanism thereon; Figure B exhibits a plan of the first floor;
Figure C a plan of the second floor; Figure D is a plan of the third or top
floor; Figure E an irregular vertical and transverse section introducing the
mill and bakery; Figure F is also an irregular and transverse section, intro-
ducing the engine house and other parts; Figure G exhibits a vertical and
longitudinal section through the middle of the building; Figure II is also a
vertical and longitudinal section of the building on the receiving and mill side.
A sack of wheat is represented at 1, being raised by the sack tackle 2, and is
at once landed on to a weighing machine situated in the receiving room on the
first floor, and when weighed and examined is discharged into the receiving
bopper 3, whence it runs into the cans of the double wheat elevator 4, where
it is exposed to warm air in its ascent to the top of the building, and there
discharged on to the creper 5, so arranged, according to circumstances, as to
convey the grain by the spouts 6 into any part of the various garners.
To operate upon such grain as requires washing and purifying it is delivered
from garner 7 into the hopper 8, that conducts it into the "scouring, washing,
and separating machine" 9, for which I have already received his Majesty's
Letters Patent, dated the Twenty-fourth January, in the third year of his reign,
and the particular description of which is given in my Specification of the said
Patent, inrolled in His Majesty's High Court of Chancery on the Twenty-
fourth July One thousand eight hundred and thirty-three; but, for the infor-
mation of the public, I think it proper to remark in this place that the
efficiency of that machine is increased by fixing a board in a radial position on
to the axis by which the grain is unavoidably carried to the top of the cylinder
and consequently more agitated. After the grain has been cleansed in the
said machine it is discharged into a hopper 10, wherein it is allowed to drain.
The grain which has undergone the last operation is then to be dried. For
this purpose, I employ the heated air given off from the vapour pipe in the
water distillery, hereinafter explained. This heated air is conducted imme-
diately underneath the kiln screens 11, over which the moist corn from the
preceding process is descending in its course to the cleansing machines 12.
In some cases I find it desirable to dry the grain in other parts of the
manufactory by a machine of the same kind, rendered portable for that; purpose,
which is particularly explained herein-after with reference to the separate
Figures I and J. It will be observed that, by the mechanical arrangements
previously described, the wheat from the time it enters the manufactory to the
period it is delivered into the cleaning and drying room is exposed to the
constant action of warm air, and consequently does not require the kiln process
just described; the grain is, therefore, conducted from the garners on to con-

page_text: veniently situated screens which deliver it into any of the sieves 22, where it
is cleaned and agitated in warm air, hence it descends over the joggling screens
23 into the cooling and grinding garners. Into these garners the grain from
the kiln screens, before mentioned, after passing through one of the seives 22
descends in a similar manner. (Note. It is proper to state, that the sieves
delineated at 22 are designed to represent Tuxford's Patent sieves or rycing
machine;" but these machines do not necessarily form a part of my present
combination of mechanism for a bread manufactory, but have been introduced
into this Drawing merely because they are known to be efficient; for in some
cases, I adopt in preference my own machine for the same purpose, which is
described in Figures 6, 7, 8, and 9 in the Specification of my aforesaid Patent,
of One thousand eight hundred and thirty-three). From the cooling and
grinding garners the wheat descends through small apertures in the arched
floor 69 into the hopper of each mill 24. (Note. The mills here introduced
are made according to my former Patent of One thousand eight hundred and
thirty-three; but I conceive it proper bere to state that the experience I have
had in the construction and working these mills has led me to prefer, for
general purposes, two pair of stones to each mill instead of three pair, as
represented in the Drawing of my aforesaid former Patent; and that by my
present modification of these machines I take the fine flour from the first pair
of stones, and the coarse meal which descends into the second pair of stones
and thereby ground, is conducted into a cylindrical dressing machine placed
underneath and within the said framing. But in the case of employing several
mills together, as in the particular example I am now setting forth of a
complete bread manufactory, I conduct all the products of the second pairs
of stones into one general dressing machine, as shewn at 25, where the
"seconds flour," and the various "offals" are separated in the usual manner
known to millers; and I do not of course in this last-mentioned case employ
any dressing machines under the mills, but which dressing machines in the
case of single mills renders the whole grinding, and dressing mechanism so
exceedingly compact and convenient as eminently to adapt it for small millering
establishments, and especially for exportation. The fine and seconds flour.
separately descend into the cans of the double-flour elevator. 26, by which it
is delivered into the flour garner 27; and in consequence of drying and pre-
paring the wheat and grinding it progressively, the flour is in a perfectly fit
and ripe state to be immediately, made into bread..
After obtaining pure and, dry flour, the next most important material in
the manufacture of wholesome bread is the water, and as no water is so pure
as that which has been distilled, nor any so economical-or-beneficial on account

page_text: of its superior solvent properties, I employ a boiler or still for this purpose,
which is represented at 28 in Fig. A. The vapour is conducted from this
vessel by a copper pipe into a refrigeratory situated in any convenient part of
the water distillery; this copper pipe, in its course to the refrigeratory, is
reduced in its dimensions and inclined downwards; it is also encased in a
wooden trough with a small space between the wood and the metal, which
space is filled with old wire gauze. One end of the said trough is opened to
the atmosphere, and the other enters a warm air shaft 29, next to the chimney;
consequently, the cold air from being minutely divided by the wire gauze,"
rapidly abstracts the heat from the vapour in the tube, and helps to condense
it; and the hot air thus obtained, and conducted into the warm air shaft, serves
for drying the grain, and for other objects of the manufacture. The pare
distilled water thus obtained is received into cast-iron enamelled cisterns of any
required temperature, and then pumped up into similar enamelled vessels in
the gas impregnating room, where the water is measured prior to its impreg-
nation with the carbonic acid gas, and atmospheric air. The apparatus I use
for this purpose is an improvement upon the former apparatus described in
my Patent of One thousand eight hundred and thirty-three. That improve-
ment I proceed to describe.
To avoid the annoyance of inhaling the carbonic acid gas, and for the
facility of supplying the gas generators 39 with water, chalk, and sulphuric
acid, as well as the removing and drying the refuse lime or plaister of Paris,
I conduct this process on the ground floor between the engine house and oven
boilers, in a compartment for that purpose. The gas generators 39 are
circular chambers formed in brickwork, the tops of which are covered with
lead. The proportions of water to chalk are nearly one gallon to one pound
of chalk, and one pound of sulphuric acid is about sufficient for one pound of
chalk. The chalk and water is well mixed or dissolved in any conveniently
situated vessel, and hence is allowed to run into a funnel of each gas gene-
rator. The chalk and water must only occupy one-third of the area of the
gas generators, the remaining two-thirds is left to admit of their increased
bulk. The chalk mixture is allowed to run in at once, but the sulphuric acid
is introduced by degrees as the gas may be wanted. The proper quantity for
each charge is measured in a moveable leaden vessel provided with a cock or
stopper which allows it to drop into an hydraulic joint in any required
quantity. This joint prevents any escape of gas, and permits the shaft of the
rouser to turn round, to which shaft is connected the inverted cup, which dips
into the acid contained in the hydraulic joint, preventing the gas from
accnding through the same, and permitting the shaft to revolve freely. It is

page_text: not necessary that the acid should be put in the joint in its concentrated form,
but after it has been measured a proportion of water may be added. The
gas ascends from the top of the generators 39 into the gas holder 31, 32.
The water measurer is represented at 30, supported upon bolts between two
beams, on which is fixed the pump framing. The gas is withdrawn from the
gasholder 31, 32, and the water from the water measurer 30, by one of the
impregnating pumps 33, wherein upon the ascent of the plunger, the water
and gas meet each other with great velocity and force, and occupy the barrel
of the pump. Upon the descent of the plunger, the atoms of the mixed gas
and water are compressed, and then forced upwards in this compressed
state into and through a very narrow annular space left between the plunger
and the inside of the barrel, and hence proceeds with great force and velocity
through a small valve into an enamelled cast-iron reservoir 34, to hold the
impregnated water for one charge. This vessel is connected by an open pipe
to a capacious and strong cast-iron gas reservoir 35, for gas under the required
pressure, which pressure is ascertained by a mercurial gage, consequently from
the open connexion of these vessels, the pressure is the same in both, but the
water vessel is made so far distinct, merely that the inside of it may be enamelled.
According to the degree of pressure of the fluids in these vessels, so will be
the degree of "lightness" or cellular state of the bread wherein they are used.
The salt having been ground by the salt mill at 70, and duly weighed and
mixed with the flour is put into the flour hopper or measure 36, to which is
attached a sleeve 37, leading into the dough machine 38. This machine
consists of a strong cast-iron cylinder with external ribs; it is placed in a
horizontal position, and supported at one end by a standard.
this standard is a circular plate, and forms the end of the
bolted to it so as to make a perfect joint. In the centre of this. end of the
cylinder is cast a boss, wherein is turned a cavity for receiving one end of
the horizontal axis 39. To this axis is securely fastened a scraper or rouser
to agitate the flour before the water is let in, and to scrape it up during, the
flowing of the water as well as afterwards. This scraper is put into action by
geer having two motions, the quick motion to agitate the flour, and the slow
to operate on the dough. There are two. doors.to the cylinder, one for the
flour at the top, and one for the dough at the end of the cylinder; the latter
is slided along the shaft to be out of the way when it is required to remove
the dough. The doors of this dough machine, are provided with screw bolts,
which only require slackening a little, and are then easily removed by sliding
out of slots made in the flanges, to which the bolts are attached by small
The top part of
cylinder, and is

page_text: chains. The process to be observed by this machine is as follows:-Fill the
machine with flour or nearly so by means of the sleeve 38 leading from the
measurer above, then close up the flour door by the bolts. When the vessel
34 is charged with the proper quantity of water, impregnated with the required
volume of carbonic acid gas, a cock or screw plug, situated between the gas
reservoir 35 and the dough machine 38, is opened, and immediately afterwards
another cock or screw plug, situated between the water reservoir 34 and the
dough machine 38, is also opened. The carbonic acid gas from the first puts
the materials in the dough machine under the same pressure as the other
vessels above, while the impregnated water from the second enters the cylin-
ders through several apertures and diffuses itself intimately amongst the
agitated flour, thus preventing the gas from escaping from the water when it
first enters the cylinder. In a few minutes the charging of the dough machino
with gas and water is completed, when the cocks or screw plugs may be closed
and the rotation of the scraper or rouser may be continued, if necessary.
The materials which the dough consists of are pure dry flour, common salt,
distilled water, carbonic acid gas, and atmospheric air. When the kneading
is completed, a cock or screw plug between the dough machine and the gas-
holder 31, 32, is opened, by which the compressed gas and atmospheric air
from the dough machine ascends into the gasholder to prevent the surplus gas
in the cylinder from being wasted. The cock or screw plug is next closed,
the bolts of the end of the cylinder are removed, which end or door is then
slided upon the axis, when the dough may be taken out of the cylinder,
allowing the same to fall upon an inclined shoot, which conducts it to the
weighing and moulding table 40. Being hero weighed and moulded into
loaves of the required size, it descends the inclined planes 41 on to small
tables 42, and is there delivered into the making-up tables 43, which con-
stitute a portion of the charging and discharging apparatus 44 of the ovens..
A similar apparatus to these is included in my former Patent before alluded
to, and specified with reference to Figures 31, 32, 33, therein delineated, so
that I need not here particularly repeat the description, but I will merely
notice those subordinate improvements which experience has led me to adopt.
Instead of using a light iron pan, on which the bread is deposited to convey it
into or out of the open, I now employ a thick cast-iron pan for the purpose of re-
taining heat during the short time it is out of the oven, and on the sides of the
said I mount four small wheels, which travel upon a raised ledge or railway
fixed on the wooden platform. This platform is firmly bolted to a light floor
for the convenience of the bakers, who are enabled to elevate or depress tho
pan

page_text: same, and to charge and dischargo the ovens by means of similar apparatus to
that described in my former Patent, but which apparatus is provided with
multiplying gear or cranework and more conveniently situated; and instead
of merely suspending the platform to the ceiling, I now steady the action of
the same by the addition of two fixed vertical rods diagonally situated, which
slide through brasses fixed to the corners of the platform.
The ovens which I use in my present new combination of machinery are
arranged in a similar manner to those described in my former Patent. (before
alluded to), but which I now modify in such manner as to simplify the parts,
and render them more easy of construction, and more certain in their operation.
The numerous steam cocks and the double steam pipes before used: to the
series of ovens for heating them separately, are now superceded by the employ-
ment of one capacious vertical cast-iron pipe, with horizontal branches from
the same to each steam box of the tier, in which boxes more steam room is
allowed; this vertical pipe has an open communication with a strong wrought-
iron boiler, which serves to convey the hot steam from and admits the con-
densed water to return into the boiler. In consequence of baking under a
slight pressure inside the oven, and substituting double for single doors, a
much less pressure of steam in the boiler and steam boxes is required, which
saves fuel, and is of great importance in other respects. The vapour that is
given off from the dough in the ovens, instead of allowing it to escape into the
atmosphere, is kept under a regulated moderate pressure (1 or 2lbs. on the inch);
this is effected by facing the doors and oven front, and having a small pipe open
to the inside of each oven and close outside of the same by a small diminish-
ing valve duly ground to fit; this valve acts simply by its own gravity, and is
provided with a vertical stem above, for the purpose of increasing or the
pressure by the addition or substraction of small circular weights, having a
hole in the centre for the stem to pass through; the greater the pressure of
the vapour in the ovens, the sooner the bread will be baked, which gives great
latitude to the baker to "time his batch." Instead of forming my steam plates
or boxes as in my former Patent, with, plane surfaces, I now cast them with
corrugated surfaces (except the railway), for increasing the heating surface,
and for the purpose of conveying the heat more quickly from the said surfaces
to the cold dough. At the commencement of the baking, it is advantageous to
cover the roof of each oven with a layer of wire gauze, the operation of which,
in rapidly communicating licat to the fresh and comparatively cold vapour,
tends to accelerate the process, and to improve the products of the baking.
The doors to the oven described in my former Patent were single or solid, by

page_text: which a portion of heat was conducted through them away, and rendered it
impracticable to bake efficiently very near to the doors; to obviate this partial
defect, I now construct the doors double, that is, with two thicknesses of metal
with an insterstice between them, more fully explained hereafter in reference to
my portable ovens in Figures K, L, M, N; to afford the necessity of forming
my ovens of different heights to suit small as well as large bread, I make
them in the first instance of one uniform height, namely 10 inches; and I
form the side ledges of the large pan, which carries the bread, with steps or
rebates, on which I deposit single and double sheet-iron pans as sufficiently
delineated, but which double pans may be better understood in Figs. K, L,
M, N; and in order that the heated vapour may freely circulate about the
bread, the ledges of the large bread pans, have suitable openings cast in them
after the bread is withdrawn from the ovens by the process already described,
it is placed upon trays and delivered into the warehouse, or it is slided at once
into cases upon wheels which convey it to its destination; for these arrange-
ments see the plan Figure A. The bread vapour which escapes from the safety
valves and from the fresh drawn bread rises to the top of the arched floor,
where there is a small opening which conveys it to the vapour shaft between
the chimney and the wall of the manufactory, which vapour shaft serves also to
carry off the moisture arising from the washed grain, and also from the grain
in the cleaning and dying room, and from other places in the manufactory,
while the vapour arising from the cold grain in the store garners and from
the flour in the flour garner, ascends to the top of the roof, and escapes
through small openings made for that purpose; the roof is boarded to prevent
condensation, and to keep the top comparatively cool in summer, and warm
in winter; the windows for the same reason should be doublo glased so as to
have a space of about half an inch between them, to prevent that condensation
of water, and opacity of the glass from pastyness which usually darkens flour
mills and large bakeries'; below the ground floor there is a large cold air flue,
with suitable openings to keep the manufactory in a proper temperature
during the summer months. Those parts of the building where fire is used
are made fireproof, and the woodwork of the other parts of the manufactory
are cooled with an alkaline preparation to prevent conflagration.
The bread manufactory I have now described is designed and calculated as
a whole, and in all its numerous parts and processes for the conversion of five
hundred quarters of wheat into bread weekly. By this example, therefore, it
will be an easy matter to construct a similar manufactory on a greater scale,
especially as most of the parts are in duplicate, for instance, one thousand

page_text: quarters, by which arrangement a great economy will be effected in the
expences or cost of production, amounting, according to my estimate, to full
twenty per centum on them. On the other hand, it will be equally easy to
construct a manufactory for two hundred and fifty quarters.
The modification of all the parts to suit every scalo of operations, and even
the details of the manufactory already described, of course render many
elaborated calculations unavoidable, though not necessary to explain in this
Specification, but which I have already prepared with great accuracy for the
information of those who may desire to carry the said Invention into effect
under my licence. To be brief, the apparatus in general may be diminished
as well as increased to any extent, and the new principles (I use this word
only in its popular sense) already illustrated thereby, carried into the metro-
polis, the village, and the kitchen, into ordinary bakers' establishments, into
the army and navy, in fine, into all places where farinacious or animal food is
prepared.
I have already constructed steam ovens of one-fourth the size delineated, as
well as portable ovens, applicable to any common fire; also some of the other
parts of my combinations to suit particular purposes, which I here state to
shew the applicability of the same principles to all dimensions, and the several
novel machines by which the entire bread manufacture is conducted may be
used in their separate or combined state, and that they, individually or
collectively, form a part of my present or aforesaid former Patent.
The portable ovens for domestic purposes, or for the use of the army and
navy, are constructed in the following manner, reference being had to Figures
K, L, M, N. Figure K exhibits an external elevation of a circular portable
oven 46, made of cast iron, having an enlarged rim 47, and provided with a
double cover 48, which, as well as the rim, are turned and ground to fit each
other, and they are fastened together by means of three locking studs rivetted
on to the rim of the pot, and three projecting pieces on the cover, so formed:
as to cause them to slide in close contact, thereby preventing the escape of
heat and vapour.
In the middle of the said double cover a safety valve is
placed, and regulated by weights, as explained with respect to the large steam
ovens before described. Fig. L exhibits a vertical section of the same parts as
those described in Figure K, with the addition of two sheet iron pans 49,
connected together by two pieces of hoop iron; the upper ends of which are
provided with a wire bail that turns down, so as to be in the recess of the pro-
jecting rim. The two pans 49 are designed for baking "small bread."
Figure M is a vertical section of Figure K, without the cover and bail, but
containing an internal vessel 50, having a series of holes in the upper part,

page_text: and one larger hole in the centre of the bottom. This perforated vessel is
provided with little studs, which keep it from the bottom and sides of the
outer pot, so as to allow a free circulation of the heat and vapour. The space
between the two vessels is gradually contracted, so as to compress the rising
hot air, and force it through the holes and over the top of the loaf. Figure N.
exhibits a section of both the outer and inner vessel, and in the bottom of the
latter is a single sheet iron pan, in which it is proposed to place an earthen-
ware vessel for delicate baking. The portable ovens thus described are
intended to be heated by suspending them over or before, or at the sides of a
common fire. By this mode of construction, the baking operation is effected
by superheated steam, or steam of a high temperaturo under a slight degree of
pressure, so as to produce an uniform constant heat throughout the process.
The points of novelty in these portable ovens, and which I claim as of my
Invention are, first, the double cover with ground edges, like a digester, whether
the same be provided with a safety valve or not, in the latter case the weight of
the lid when not fastened down operates as a safety valve; second, the inner
vessel 50, perforated in the upper part; third, the projecting rim or recess in
the outer vessel. Another oven of extreme portability and lightness is given at
Figure O. The outer vessel 51 represents a shallow sheet-iron pan, with a bail
handle to suspend it over a fire; the inner vessel 52 is also a sheet-iron pan,
having resting studs stamped out of the metal, into which is to be placed the
bread to be baked; it is then inclosed by a double cover 53 of a peculiar con-
struction. The outer piece of this double cover is formed so that the edge of
it shall come into contact with the bottom of the heated pan 51, and on the
top of this external piece is fixed a common handle; now the inside piece
of this double cover is formed of a portion of a sphere of rather less dimensions,
so that when the apex or top of the dome is brought nearly into contact with
the outer piece, it shall diverge from thence, so as to make an increasing
space between them, but the bottom or edge of this inner dome does not
touch the pan 51 within about a quarter of an inch. The two pieces forming
the double cover 53 are connected together merely by the pressure of springs,
two of which, marked 53, are shown; these are rivetted to the inner cover
and press against the outer, so as to suspend the inner one in the manner
described. In the centre of the inner dome is a hole, through which the
vapour from the bread enters when the latter has become hot, and instead of
the said vapour becoming condensed on the inner cover, it necessarily enters
and descends between the double cover, and is met by the radiated heat
arising from the circumference of the pan 51. By this simple and economical
combination the heat given off from the pan 51 is retained within the cover,

page_text: and causes the uniform heat of the vapour to be constantly pressed around
and throughout every part of the bread, so as to insure a perfect baking.
I claim in the portable oven marked Figure O, the combination of parts
set forth, whether the cover be double or single; but I claim the double cover
distinctly considered however applied for retaining heat.
For the purpose of adapting my domestic portable ovens described.. by
Figures K, L, M, N, O, for the requirement of schools or large families, I
construct a stove such as is represented in Figures P and Q, whereof P is
a plan, and Q a longitudinal and vertical, section. 54 is a fire-place, with an
ash-pit underneath having a register door; 55 is a hot-air chamber, designed
and regulated to give a uniform temperature throughout, and to cause the
heat to be asbsorbed before it enters the chimney at 55; 56 shews, a. large
iron plate covering the brickwork, having suitable circular openings.57 (see
plan) for the reception of a series of domestic portable ovens (see the section),
the projecting rims of which rest upon the peripheries of the holes in the
plate. The plate is provided with a ledge rising one inch above the plane,
which space is partly filled up flush with, a non-conducting cement. The
cement surrounds the ovens, making good the joints between them and the
plate. That end of the plate 56 which is situated over the fire, is designed
for the purpose of baking either large or small loaves, but it equally serves tho
purpose of baking or roasting meat. A warm closet is represented at 58,
and that part of the plate 56, which is situated above it, is the heating medium
by which such baking or other cooking may be performed in the manner,
already noticed.
Having given a full description of the apparatus I employ for impregnating.
the flour and dough with carbonic acid gas on the great scale, I proceed to
show the applicability of the process on a smaller scale, more especially with
the view of adapting it to the use of the navy. R is a general plan of this
apparatus as seen from above;. S is a side elevation of the same; T, another
side elevation, at right angles to the former; U is a plan of the foundation
plate, and a transverse section of the lower ends of the standards. The gas-
holder 58, supplied by a generating apparatus conveniently situated but not
introduced into the Drawing, is suspended from two pullies fixed in a pro-
jecting piece fastened to the top of the gas, reservoir, 60. The water measurer
5 is shewn at 61. The action of the pump draws the water and the gas from
their respective places by the pipes shown at 62 and 63, forces the combined
fluids. through a pipe 63 into the condensed carbonated water reservoir 64,
which has an open communication by the pipe 65 with the condensed gas
reservoir 60. The dough machine 66, constructed internally as described.

page_text: with reference to the large manufactory, and supposed to be filled with
flour, is now to be charged with gas by opening the cock in the pipe 67.
The cock in the pipe 68 is immediately opened, when the water in the
vessel 64 is discharged into the dough machine. In a few minutes the
charging will be completed in the cylinder, when the cocks may be closed.
The remainder of the process has been sufficiently described in the former part
of my Specification.
In order to extend the utility of my Invention to bakers, pastrycooks, and
to the public in general, it is a part of my system of improvements to supply
them with carbonated or acrated water in vessels highly charged with the
same, in much the same manner as was a few years ago adopted in London
and other places in supplying the inhabitants with carburetted hydrogen in
portable vessels for illumination. The vessels I propose to use for this pur-
pose are made of cast iron, enamelled on the inside, similar to the vessel 6-4,
but made of any requisite dimensions, or they may be of common glass; and
my process for charging these portable carbonated water vessels is precisely
the same as that described for charging the dough machine with gas and
carbonated water, that is, by filling the vessel with the gas at the required
pressure prior to letting in the water. With one of these charged carbonated
water vessels a baker or pastrycook may make bread or pastry as cellular or
spongy as may be desired. The chemist, or druggist, or other shopkeeper may
receive a reservoir of water similarly prepared, and draw off at pleasure for
their customers glasses of "soda water," or they may obtain of the Patentee
the complete machine itself for making the carbonated water. The details of
such machine it will be needless to describe, since it is only necessary to con-
ceive the pipes and valves by which the dough machine is charged to be
removed and substituted by another system of pipes and valves performing the
same offices and employed to fill any kind of bottles, as delineated in the same
Figures. 70 shows a bottle to be charged; 71, a valve and pipe to convey the
gas from the top of the reservoir 64; and 72, another valve and pipe to convey
the carbonated water from the bottom of the said reservoir. These two valves
are united by a lever handle, so that the valve 71 shall be opened an instant
before the valve 72, which is designed to insure an abundant impregnation.
This machine is a necessary constituent part of my before-described apparatus
for the preparation of unfermented bread, and I therefore claim it both in its
combination with a dough machine and without the same. The impregnating
pump I use is of a novel construction, which I proceed to explain with refer-
ence to Figures V and W; V being a vertical section, and W an external
elevation.
73 is a solid plunger working a barrel 74; 75 is the stuffing box;

page_text: 76, the bottom plate, containing in the centre the induction valve, underneath
which are the passages for the gas and water; 77 is the eduction passage and
valve through which the carbonated water is forced out. All the parts inside
of this pump except the valves and their seats are made of cast iron, with
enamelled surfaces, which enamelling is effected by the same process as that
practised by the manufacturers of enamelled culinary vessels; but the enamel-
ling of metallic pumps being entirely new and beneficial, I claim it as one of
my improvements. It being at certain times desirable and economical in some
situations to purchase grain at a distant port, and such grain in the winter
months is frequently too damp for shipment, I propose to dry the same in my
portable kiln, referred to in the early part of this Specification, which I now
proceed to describe.
Fig. I is a vertical section, and Fig. J, a plan. A series of kiln screens are re-
presented at 11, supported on one side by hinge joints, and on the other suspended
by cords, and counterbalanced by weights, by which the inclination of the screens
is regulated, so as to cause the grain to run down them from the close hopper
12, with the speed, or in the quantity required. The bottom screen discharges
itself into a fixed shoot 13, which is divided into partitions so as to deliver the
grain into any number of bags that may be desired. A small moveable fire
grate is represented at 14, standing insido, a tapered cast-iron pipe 15, the
exterior of which is corrugated into a series of horizontal grooves, so as to pre-
sent a great surface and cause the ascending column of air in its progress to
impinge against the projections. The tapered form of the pipe is given to it
to favour the absorption of heat before it enters the chimney 16 above, and the
projections formed by the grooves thereon serve also to support a series of
pieces of wire gauze 17, to interrupt the air. This wire gauze serves to divido
the air minutely, conveying by its conducting property and great surface the
heat from the pipe to the air in its passage upwards. In order that the corn
passing through the machine may leave it at the bottom in a comparatively
cool state, the hot air is not introduced as usual at the bottom of the kiln, but
enters from the hot-air generater at 18, from which place up to 19 there is a
longitudinal opening covered with wirework; from 19 to 20 there is a free
opening, which admits of a volume of hot dry air to enter, thus preventing the
vapour rising from the corn beneath becoming condensed, and thereby obvia-
ting, one of the injurious effects common to all other kilns, and by employing
a current of pure warm air instead of the sulphurous and smoky hot air given
off from coke or turf, other injurious effects are entirely obviated.
My claims to Invention in this kiln is, the general arrangement of the

page_text: whole and in the employment of wire gauze as a medium for minutely dividing
the air and rapidly communicating heat thereto.
In witness whereof, I, the said Luke Hebert, have hereunto set my hand
and scal, this Second day of December, in the year of our Lord One
thousand eight hundred and thirty-six.