IMPROVEMENTS IN THE MANU- FACTURE OF DOUGH AND BREAD
Year: 1864

page_text: LETTERS PATENT to Richard Waugh MacArthur, of 56, York Terrace,
Regent's Park, London, William Augustus Guy, of 26, Gordon Street,
Gordon Square, London, and Edmund Edwards, of 1, York Buildings,
Adelphi, London, for the Invention of "IMPROVEMENTS IN THE MANU-
FACTURE OF DOUGH AND BREAD."
Sealed the 16th December 1864, and dated the 24th June 1864.
PROVISIONAL SPECIFICATION left by the said Richard Waugh Mac-
Arthur, William Augustus Guy, and Edmund Edwards, at the Office
of the Commissioners of Patents, with their Petition, on the 24th June
1864.
We, RICHARD WAUGH MACARTHUR, of 56, York Terrace, Regent's Park,
London, WILLIAM AUGUSTUS GUY, of 26, Gordon Street, Gordon Square,
London, and EDMUND EDWARDS, of 1, York Buildings, Adelphi, London, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN THE
MANUFACTURE OF DOUGH AND BREAD," to be as follows:-
This Invention consists in arranging one or more vessels of suitable form
and material, having openings which can be readily closed air-tight and
through which flour can be introduced, and also openings connected with a
reservoir from which salt and water can be introduced.
These vessels also contain mixing arms so arranged upon a shaft that the
latter can be caused to revolve by any convenient power, which also drives a
forcing pump or pumps by which carbonic acid or other suitable gas can be
forced into the vessels. This carbonic acid or other gas may be generated in

page_text: and stored in a gas-holder, whence it is pumped when
any convenient way
required; or it may be generated in suitable vessels under very high pressure,
whence it may be allowed to escape directly into the mixing vessels without
pumping; and these generating vessels may be made fixed or moveable, so that
they can be carried to the mixing vessels; or the carbonic acid gas may be
generated from muriatic acid and carbonate of soda in such proportions that
the resulting compound may be common salt which may be used in mixing
the dough. Two or more of these mixing vessels are so arranged that when
one of them has been partially filled with flour, salt, and water (or other
materials for making dough for bread), the mixing arms can be caused to
revolve, and thus to combine the several ingredients into dough. Before the
mixing arms are made to revolve, or in some cases during the time they are
revolving, or after they have by their revolution completed the mixture of the
dough, or in some cases continuously during these periods, carbonic acid or
other gas generated in any suitable manner is forced into the vessel. The
flour, salt, and water are thus converted into dough strongly impregnated
with carbonic acid or other gas. All these operations, that is to say, the
mixing of the dough and the impregnation with gas, are carried on in the
same vessel. At the bottom of each vessel is a discharging aperture, having
a cock or valve, of the kind herein-after described or of any other suitable
form, from which the dough may be measured and discharged by the pressure
of the gas above it. Whilst one of the vessels has been thus emptied of dough
and retains only carbonic acid gas at a great pressure, another vessel has been
charged with flour, salt, and water, and has been closed air-tight, a pipe is
then opened by which a communication is made between the two vessels, and
part of the carbonic acid gas is allowed to flow from the emptied vessel to the
full one.
This pipe is then closed and carbonic acid gas is introduced into
the full vessel, and its mixing arms are caused to revolve, whilst the emptied
vessel is opened and refilled, and so on alternately. And in some cases we
prefer to allow the carbonic acid gas which remains in an emptied mixing
vessel (after a communiction has been opened and closed between it and a
full one) to escape through a pipe into a cistern containing liquor ammoniæ
or other suitable substance by which the carbonic gas is absorbed, and which
may be afterwards utilized in making bread or in any suitable way. The cock
or valve above described consists of a curved flange attached to the discharging
aperture of the mixing vessel. Working against this flange is a curved band
of the same width and forming a segment of a circle turning on a centre
which is also the centre of the curve of the flange. To one end of this
segment is attached a box or receptacle sufficiently large to hold the dough

page_text: required for one loaf. When the band is turned so that this end of it is opposite to
the discharging aperture of the mixing vessel the box becomes filled with dough,
and when the band is turned the mouth of the box is turned downwards with
it, and the dough falls out, whilst the remaining part of the band closes the
aperture of the mixing vessel. Another form of cock which we use consists
of a conical tube attached with its widest part downwards to the discharging
aperture of the mixing vessel. The upper part of this tube is closed by a
cock and the lower part by a moveable plate, and the space between them is
sufficiently large to hold the dough for one loaf, and the cock and plate so
arranged are connected together by means of levers, so that when one is closed
the other is open, and vice versa. When the cock is open and the plate
closed the dough descends into the intermediate space, and is thus measured
off, and when the cock is closed and the plate opened, the dough expands
and falls out from the conical tube: And in some cases instead of a cock
and plate as described, we use two cocks or two plates opening and closing
alternately.
Great economy is effected by this Invention in the first cost of the machine
by the whole of the processes of mixing the materials and impregnating them
with gas being carried on in one vessel instead of in two or more, as has
heretofore been done, and by the use of the cock or valve described, and by
the use of liquor ammoniæ or other suitable substance as described. And
great economy in time is effected by the use of one such vessel at a time and
by the mode in which a part of the compressed gas is allowed to pass from an
empty mixing vessel to a full one, or to be utilized as described, instead of
being allowed to escape as heretofore or being pumped by force pumps from
one vessel to another. And great safety is attained by the use of one vessel
as described for mixing the dough, and thus avoiding the possibility of the
flour or other ingredients used being blown out through any discharging aper-
ture left accidentally open, as may be the case where the gas under high
pressure is admitted upon the dry flour in the mixing vessel.

page_text: AUGUSTUS GUY, of 26, Gordon Street, Gordon Square, London, and EDMUND
EDWARDS, of 1, York Buildings, Adelphi, London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fourth day of June, in the year of our
Lord One thousand eight hundred and sixty-four, in the twenty-seventh year
of Her reign, did, for Herself, Her heirs and successors, give and grant unto
us, the said Richard Waugh MacArthur, William Augustus Guy, and
Edmund Edwards, Her special licence that we, the said Richard Waugh
MacArthur, William Augustus Guy, and Edmund Edwards, our executors,
administrators, and assigns, or such others as we, the said Richard Waugh
MacArthur, William Augustus Guy, and Edmund Edwards, our 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 THE MANUFACTURE OF
DOUGH AND BREAD," upon the condition (amongst others) that we, the said
Richard Waugh MacArthur, William Augustus Guy, and Edmund Edwards,
our executors or administrators, by an instrument in writing under our or
one of our, or their, or one of their hands and seals, 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
Seal Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that we, the said Richard Waugh MacArthur, William
Augustus Guy, and Edmund Edwards, do hereby declare the nature of our
said Invention, and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement, and
accompanying Drawings, that is to say :-
This Invention consists in mixing carbonic acid gas, or other suitable gas,
with the flour, water, and salt, and other materials for making bread, cakes,
biscuits, and other farinaceous compounds. This we do either by aërating
with gas the water with which such materials are mixed under ordinary
atmospheric pressure, or under greater pressure, or by generating carbonic
acid gas, or other suitable gas or vapour, in the substance of the dough by the
addition of materials, such as carbonate of soda and muriatic acid, which by
their chemical action may generate gas or vapour, or by the ordinary process
of fermentation, or by a combination of some or all of these methods.
We make the dough thus aërated in ordinary kneading troughs, or in

page_text: mixing vessels of any suitable form and material, and when the ingredients
are thoroughly mixed and incorporated into dough we cut it into pieces of a
size suitable for the bread or other articles required. We sometimes do this
by hand, but we prefer to force the dough from the vessel or trough in which
it has been mixed by mechanical, gaseous, or other suitable pressure through
an opening of convenient size; and we cut the dough into pieces as it issues
from this opening, either by hand or by means of knives, or cutting wires
worked by the same power which expels the dough from the trough or mixing
vessel; or we measure and discharge the dough by means of any suitable
cock or other apparatus. The pieces of aërated dough having been thus cut
or measured to a proper size, each piece is placed into a mould or tin, or upon
a plate or tile, and these moulds or plates are then placed together or sepa-
rately into or under a receiver, from which the air is then partially withdrawn
by means of an air pump or other suitable means. The carbonic acid or
other gas or vapour in the dough (whether formed by the aëration of the
water with which the dough is mixed, or by generation by chemical compounds
in the dough, or by fermentation, or by a combination of some or all of these
methods) is thus allowed to expand, and the dough rises and becomes spongy
and fit for baking. And we create the partial vacuum in the receivers either
by means of air pumps worked as long as may be necessary previous to
and during the baking of the bread or other articles; or, in some cases, where
much vapour has to be exhausted, we open a pipe from the receiver to a con-
densing vessel, in which the vapour is condensed by means of a jet of cold
water, the resulting liquid being removed (as well as any air) by means of a
pump, as is done in an ordinary condensing steam engine. When the dough
has thus been caused to rise sufficiently, the partially exhausted receivers are
placed in a suitable oven in which the dough is baked; and, if necessary, the
exhaustion of the receivers can be continued during the process of baking, or
for as long a time as may be advisable. Air is then re-admitted whilst the
baking is continued, and the bread or other articles are removed finished.
Sometimes we make the receiver from which the air is exhausted form a part
of the oven, so that the bottom of the receiver may be directly over the fire
by which the oven is heated, and the moulds containing the dough are placed
at once in the oven, from which the air is then withdrawn. And sometimes we
make the bed of the oven circular, and cause it to revolve horizontally or
vertically over the fire, and we make the fire-places either fixed or moveable.
In some cases we use superheated steam, or water, or oil instead of the
direct action of fire, to give out the necessary heat for baking the bread.

page_text: And in order more readily to exhaust the air from the receivers, we we make
them with doors, which can be closed air-tight, and attach to them valves or
cocks, by which they may be made to communicate with the apparatus for
exhausting the air. Or sometimes when the receiver forms part of the oven,
the upper part of it is made is made to lift up, so that the moulds containing
dough can be placed on the bed of the oven, over which the cover can then be
lowered. And we make an air-tight joint at the lower edge of the cover by
means of a strip of leather or other flexible substance kept sufficiently moist;
or we make it to dip, when lowered, into a groove or recess partially filled
with fusible metal, mercury, or other suitable fluid substance, and the air is
then withdrawn from the receiver whilst the dough is being baked; the
fusible metal or other fluid substance forming a perfectly air-tight joint, and
preventing the admission of air into the vacuum.
And we attach a cock to
the receiver, by which air can be partially or entirely re-admitted, or by which
steam or other vapour can be admitted if required.
Sometimes we take the pieces of dough and pass them into a tube or
chamber sufficiently heated, and immediately exhaust the air. The dough
thus rises rapidly, and the heat is sufficient to crust or partially bake it very
quickly, and when it is sufficiently set we admit the air, and remove the
bread to ordinary ovens, where the baking is completed.
In illustration of this Invention the accompanying Sheet of Drawings
contains Figures exhibiting some of the forms and arrangements which we
give to apparatus constructed according to our Invention.
Figure 1 shews a receiver in which the pieces of dough may be placed, and
from which the air may be withdrawn whilst the dough is being baked.
A is a plate, upon which the moulds or tiles holding the pieces of dough
are placed, and B is a cover of sufficient strength, which is then placed over
the dough, and which forms an air-tight joint where it rests upon the plate A.
Air is withdrawn by means of the cock and pipe C, and the apparatus is
placed in an oven, the exhaustion being continued, if necessary, whilst the
dough is being baked by means of a flexible or other pipe. Air is then
re-admitted, when the bread has been sufficiently hardened by baking to
prevent its collapse.
Figure 2 is another form of receiver which we use.
A is a strong vessel sufficiently large to admit one or more loaves of bread
in moulds from the end B. This vessel forms the oven, and is fixed above or
adjoining the fire, and several may be placed above or by the side of one
another. When a sufficient number of moulds have been placed in the

page_text: receiver A, the mouth B is closed by the air-tight door C, and the air is
exhausted through the cock D whilst the bread is baked. Air is then
re-admitted, the door C is opened, and the bread removed.
Figure 3 shews a form of receiver in which a joint of fusible metal,
mercury, or other suitable fluid substance is used instead of an air-tight door.
A is a vessel of iron or other sufficiently strong material, into which the
moulds containing dough are placed on frames above one another. This
vessel is about thirty inches or more deep, and is surrounded by a narrow
groove or recess B, which is partially filled with mercury or fusible metal;
C is a cover, the lower edge of which dips into the recess B, thus forming an
air-tight joint, when the air is removed from the interior of the vessel A by
means of a cock and pipe at D (or E.) If the whole of the air were
removed the mercury would rise to a height of about thirty inches more on
the inside than on the outside of the cover C, and if the air be only partially
exhausted it will rise to a proportionally less height.
Figure 4 shews a large receiver, which forms a part of the oven.
A is the bed of the receiver, of iron or other material of sufficient strength,
which may be lined with bricks or tiles; B is a strong cover, which can be
raised or lowered from the bed A by means of the chain C and a counter-
weight. The bed A is covered with the pieces of dough to be baked, and the
cover B is lowered over them, forming an air-tight joint at D, by means of a
strip of leather or other suitable substance kept constantly moist. The air is
then exhausted through the cock E, and the dough is partially baked. Air
is then re-admitted, the baking continued, and the cover being raised the
bread is removed. The flues of the oven may be made to pass over the top
and round the sides, as well as under the bottom of the receiver, or the
oven may be heated by raising the cover and introducing wood, or other
burning fuel, or ignited gas, which is removed when the oven is sufficiently
heated, and the dough having been introduced the cover is lowered, and the
air exhausted. Both the bed and cover of the oven may be lined or
surrounded with tiles, clay, or nonconducting material to retain the heat.
Another form of this receiver is shewn at Figure 5, where the air-tight
joint is made in the same way as in Figure 3. A is the bed of the oven,
round the edge of which is formed a groove or recess B filled with mercury
or fusible metal, above which is constantly kept a small quantity of water.
The lower edge of the cover C dips into the groove B, and thus forms an air-
tight joint, whilst the air is withdrawn from the receiver, and the dough in it
is wholly or partially baked. When the air has been re-admitted to the
receiver the cover C is lifted, and the moulds of bread are removed. The

page_text: flues may be made to pass round the sides and top of this receiver also, in the
same way as already described in Figure 4.
Having now described our said Invention, and the manner in which it is
intended to be worked, we wish it to be understood that we do not claim the
making of bread with water aërated with carbonic acid or other gas, nor do
we confine ourselves to the details, but we claim as our Invention,―
First, the raising of dough for bread, cakes, biscuits, or other farinaceous
compounds by causing carbonic acid or other gas in it (whether formed by
the aëration of the water with which such dough is mixed under ordinary
atmospheric or greater pressure, or by the generation of such gas in the
dough by chemical action, or by ordinary fermentation) to expand by
removing the pressure of the atmosphere from it.
Second, the novel combination and arrangement of the several parts of
the apparatus herein described for the purpose of manufacturing bread, as
herein-before set forth.
Third, the arrangement of receivers, which may be closed air-tight, for
causing dough containing gas to expand by removing from it the pressure of
the atmosphere.
Fourth, the novel combination of an air-tight joint, consisting of a groove
filled with mercury, fusible metal, or other suitable fluid substance, with
apparatus for causing dough to expand by removing the pressure of the
atmosphere from it.
In witness whereof, I, the said Edmund Edwards, on behalf of myself
and the said Richard Waugh MacArthur and William Augustus
Guy, hath hereunto set my hand and seal, this Twenty-second day of
December, in the year of our Lord One thousand eight hundred and
sixty-four.
Witness,
T. E. HEWETT,
of 1, York Buildings,
Adelphi.
EDMUND EDWARDS. (L.s.)