IMPROVEMENTS IN APPARATUS DAYTHA DE NANO
Year: 1875

page_text: LETTERS PATENT to John Chapman Peacock, of 14, Queen Square,
Bloomsbury, and Thomas Rudkin, of the Griffin's Tavern, Meat
Market, Smithfield, for the Invention of "IMPROVEMENTS IN APPARATUS
DAYTHA DE NANO"
Sealed the 16th April 1875, and dated the 18th February 1875.
PROVISIONAL SPECIFICATION left by the said John Chapman Peacock
and Thomas Rudkin at the Office of the Commissioners of Patents,
with their Petition, on the 18th February 1875.
We, JOHN CHAPMAN PEACOCK, of 14, Queen Square, Bloomsbury, and
THOMAS RUDKIN, of the Griffin's Tavern, Meat Market, Smithfield, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
APPARATUS FOR COOKING AND BOILING BY MEANS OF GAS," to be as follows:-
In the Specification of a Patent granted to one of us, No. 1065, in
the year 1874, gas ovens or roasters are described. They consist of a
chamber suitably arranged and fitted and surrounded with non-con-
ducting material within the chamber at one end, and near the bottom
is a gas burner supplied with air through openings. The quantity of

page_text: air thus admitted into the chamber to the burner can be regulated by a
valve. The outlet for the products of combustion is at the lower part
of the chamber into a flue pipe in which there is a regulating valve or
damper.
According to the present Invention the products of combustion are
still drawn from the lower part of the chamber, but they are conveyed
to the top of the chamber and so into the flue pipe by a channel which
is separated from the cooking space only by a partition of thin metal,
which readily conducts heat, so that when the gas is first lighted the
air in the channel is at once heated by conduction through the metal 1
partition, and thus the draft is started much sooner than it would be if
dependent on heated air entering the channel and flue from the bottom
of the chamber. The partition by preference should expose a con-
siderable extent of conducting and heating surface, and it may be
arranged in different forms. A flat partition fixed at a short distance ]
from the end of the chamber is a simple and efficient arrangement, but
an oval tube, or a series of tubes has the advantage of exposing a larger
surface.
The bottom of the chamber we make without any non-conducting
material; we form upon it a box of sheet iron, into which plates and
dishes may be placed to warm them; the top of this box in fact forms
the bottom of the cooking space, and both the gas burner and the outlet
for the products of combustion are below it.
Over the gas burner and near the top of the chamber we fix a curved
plate to direct the ascending current of hot air along the top of the
chamber, and so obtain a more regular circulation of the hot air.
For broiling meat we make a gas gridiron of a number of parallel
bars; they are attached to a gas pipe, and are hollow, and provided with
nipples or burners, at which the gas is lighted. Similar gridirons have
before been constructed, but the fat has been found to clog the gas
nipples. Now we form the bars with hoods or roofs projecting over the
nipples, which are secured into the bars along the sides. Each nipple
is thus protected with a hood or roof, between which there are channels
for the fat to run down to the under side of the bar. The bars are set
in an inclined position, and the fat drips from their ends into a suitable
receiver.

page_text: inlet air for combustion of the gas and the outlet products of com-
bustion. Over the entire surface of the boiler, excepting the bottom, we
place a jacket of sheet iron of exactly the same shape as the boiler and
having an interval of from 2 to 3 inches between the two. We carry
this jacket round the edge of the bottom of the boiler and fix it to the
curtain before described.
Halfway between the boiler and jacket we fix a tube or curtain with
its lower edge attached to the jacket and its upper edge reaching about
half the height of the boiler. At the lowest part of this jacket and
outside the curtain we insert two chimneys or flues, one on each side of
the boiler, and we carry them upwards and make them to follow the
course of the jacket, but leaving an interval of one inch or more between
the jacket and flue, excepting for a distance of, say, six inches from the
top of the dome, at which part we make the flues touch the boiler and
then meet together in the centre. We then carry them upwards in a
single flue either into an ordinary chimney or the open air.
Through the centre of this last named chimney we sometimes pass
the steam pipe from the boiler. The reason for this arrangement of the
flues is to allow the heated air from the burners to warm the top of the
flues immediately the gas is lighted, expand the air within [the upper
part of the flue, and thus to cause a draught to be established at the
moment of lighting the gas. Outside all we fix a jacket of wood, leaving
an interval of from 2 to 4 inches, which interval we fill with any suitable
non-conducting material.
The burner we make in rays, star shaped, each ray being screwed
into a central chamber; and we make the whole to take the form of
the bottom of the boiler. Each of these rays has a short chimney
running its whole length, with the spaces between each ray stopped to
prevent the passage of air. The whole combined burner we enclose in
a tube or curtain open at the bottom for the admission of air.
By this
arrangement no air can pass through the flue tubes in the boiler,
excepting it first pass through or in close proximity to the flames of the
burning gas.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Chapman Peacock and Thomas Rudkin in
the Great Seal Patent Office on the 18th August 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JOHN
CHAPMAN PEACOCK, of 14, Queen Square, Bloomsbury, and THOMAS
RUDKIN, of the Griffin's Tavern, Meat Market, Smithfield, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighteenth day of February, 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 successors,
give and grant unto us, the said John Chapman Peacock and Thomas
Rudkin, Her special license that we, the said John Chapman Peacock
and Thomas Rudkin, our executors, administrators, and assigns, or such
others as we, the said John Chapman Peacock and Thomas Rudkin, 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 "In-
PROVEMENTS IN APPARATUS FOR COOKING AND BOILING BY MEANS OF GAS," upon
the condition (amongst others) that we, the said John Chapman Peacock
and Thomas Rudkin, our executors or administrators, by an instrument
in writing under our or their hands and seals, or under the hand and
seal of one of us or them, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to be
performed, and cause the samo 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 John Chapman Peacock and
Thomas Rudkin, 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 thereof,
that is to say :-
In the Specification of a Patent granted to one of no No 10CE
1

page_text: chamber suitably arranged and fitted and surrounded with non-
conducting material within the chamber at one end, and near the
bottom is a gas burner supplied with air through openings. The
quantity of air thus admitted into the chamber to the burner can be
regulated by a valve. The outlet for the products of combustion is at
the lower part of the chamber into a flue pipe in which there is a
regulating valve or damper.
According to the present Invention the products of combustion are
still drawn from the lower part of the chamber, but they are conveyed
to the top of the chamber and so into the flue pipe by a channel, which
is separated from the cooking space only by a partition of thin metal
which readily conducts heat, so that when the gas is first lighted the air
in the channel is at once heated by conduction through the metal
partition, and thus the draft is started much sooner than it would be if
dependent on heated air entering the channel and flue from the bottom
of the chamber. The partition by preference should expose a con-
siderable extent of conducting and heating surface, and it may be
arranged in different forms. A flat partition fixed at a short distance
from the end of the chamber is a simple and efficient arrangement, but
an oval tube or a series of tubes has the advantage of exposing a larger
surface.
The bottom of the chamber we make without any non-conducting
material; wc form upon it a box of sheet iron into which plates and
dishes may be placed to warm them, the top of this box in fact forms
the bottom of the cooking space, and both the gas burner and the outlet
for the products of combustion are below it.
Over the gas burner and near the top of the chamber we fix a curved
plate to direct the ascending current of hot air along the top of the
chamber, and so obtain a more regular circulation of the hot air.
Figure 1 is a longitudinal section of an oven constructed according to
our Invention; a is a metal plate forming the foundation or bed; bis
the inner casing of the oven or chamber consisting of thin sheet iron;
c is the doorway frame, and d, the door frame; they are made to fit
accurately to prevent the entrance of air by the doorway when the door
is closed; e is the outer casing of the chamber, and f, the outer casing
of the door, both of which we prefer to make of wood; g is an iron plate
forming the top of the chamber. The door is hinged on one side and

page_text: provided with a latch at the other as is usual.
In the space between the
outer and inner cases we place the non-conducting material as described
in the Complete Specification filed by one of us, No. 2833, in the year
1874. The gas burner is carried by the door and is supplied with gas
by a flexible or jointed pipe. The burner as shown consists of two tubes
fixed parallel to each other, and extending almost the entire width of the
door, and each tube is perforated along its upper side with a row of fine
holes for the passage of, the gas. The burner / is enclosed in an oblong
metal chimney or casing i open at top and bottom, but capable of being
closed at the bottom either partially or entirely by means of a sliding
plate; is a curved plate attached to the door; it is intended to direct
the current of hot air rising from the gas burner; is the outlet at the
bottom of the cooking chamber opening into a flue m, which is
partitioned off from the heated chamber by the thin metal partition n.
In connection with the flue m is the chimney pipe o, it is provided with
a regulating valve o¹. As soon as the gas is lighted and heats the air in
the chamber the heat is conducted through the plate n and establishes
at once an upward current in the flue m. But for this device of heating
the air in the ascending flue by conduction it would take a considerable
time for the proper draft of air to be established.
As before-mentioned metal tubes may be substituted for the plate n;
p is a box with a flap door in front which serves to receive plates and
dishes, and also as a stand for a large dripping pan.
The partition or tubes may be passed through the bottom of the
chamber, and the products collected by means of a suitable channel
fixed at the bottom as shewn in the Drawing.
We would remark that these ovens or gas cooking apparatus are
applicable not only in the preparation of food, but also when made
sufficiently large in a variety of manufacturing and other operations,
involving baking, or cooking or analogous processes, as for example, in
the stoving of papier maché or of varnished or enamelled or lacquered
articles, and they may also be used as drying closets. When it is
necessary to pass away any vapour arising from the products of com-
bustion or the cooking or drying at the top of the heated chamber,
we employ a moveable plate (see p Figure 2) touching the bottom of the
hot chamber, and having an airway at the top so as to conduct the
vapour from the top downwards behind this second plate and so out as

page_text: ´before described. At the commencement of the operation and until the
draft is fairly started, the plate p is so placed as to allow the draft to
pass off from the bottom, but when ventilation from the top is required
it is brought to the position in which the Drawing shows it. This plate
is so hung that it may be easily moved without opening the door at the
front of the heated chamber.
We claim as respects this part of our Invention the method of heating
the air in the ascending flue, passing upwards from the bottom of the
oven or heated chamber by conduction through the wall of the flue
substantially as described.
We also claim the general arrangement of a gas oven substantially as
described and shewn in the annexed Drawing.
For broiling meat we make a gas gridiron of a number of parallel
bars; they are attached to a gas pipe, and are hollow and provided with
nipples or burners at which the gas is lighted.
Gas gridirons have before been constructed, but the fat has been
found to clog the gas nipples. Now we form the bars with hoods or
roofs projecting over the nipples, which are secured into the bars along
the sides. Each nipple is thus protected with a hood or roof, and
between these there are channels for the fat to run down to the under
side of the bar. The bars are set in an inclined position, and the fat
drips from their ends into a suitable receiver.
Figure 3 is a perspective view of a gas gridiron constructed according
to this part of our Invention. a is the gas supply pipe connected
through the taps 6, 6, with the pipe c, which forms the front bar of the a
gridiron; this pipe is stopped by a plug at c¹; d, d, are the parallel bars
of the gridiron; they are cast tubes screwed at one end into tapped holes
in the pipe c, and closed at the other end. The tubes d are perforated
along their sides, and a small gas nipple is screwed into each perforation.
Over each nipple a hood d' is formed on the tube, as is shown clearly, 3
and to a larger scale, full size or thereabout, in the Figures 4. These
hoods prevent the melted fat running over the gas nipples and direct it
between them; it then runs down the under sides of the tubes which are
somewhat inclined to their ends, where it drips off into a trough provided
to receive it.
We claim as respects this part of our Invention the construction of
3

page_text: gas gridirons with hoods to protect the gas nipples or perforations
substantially as described.
For boiling water either to obtain hot water or steam for cooking and
other purposes, we employ a boiler circular in plan and domed at top
and bottom. Beneath its bottom we place a gas burner. The lower
part of the boiler together with the gas burner is enclosed within a casing,
in which is an aperture to admit air to the burner, and a narrow space
is left between the casing and the side of the boiler for the passage
upwards of the products of combustion. Over the boiler and this inner
casing is placed a second casing formed like a bell which the ascending
products of combustion enter, and they have then to descend until they
escape round the lower edge of the bell-form casing, which is by
preference beneath the level of the burner. The products of combustion
thus enter into an outer casing, and they ascend within it and outside
the bell-form casing before mentioned to a flue at the top. Around the
outer casing is a packing of non-conducting material contained within a
wooden lagging.
The boiler is furnished with a supply cistern which is also surrounded
with non-conducting material, and is provided with a water supply
valve controlled in the usual manner by a float.
Figure 5 is a vertical section of our water boiler. a, a, is the bed
plate, upon it stands an annular hollow casing 6 which is filled with
non-conducting material. On the casing 6 the supports c are placed at
intervals, and they sustain the boiler d. e is the feed pipe for which a
passage is provided through the casing 6; f is the steam pipe passing
away from the crown of the boiler; g is a safety valve upon the steam
pipe; is a casing of sheet iron, which together with the casing b
encloses the sides and bottom of the boiler excepting an aperture left for
the insertion and withdrawal of the gas burner. This aperture is further
contracted by a double moveable ring i filled with non-conducting
material, and in the centre of this ring the opening left is no larger than
is necessary to convey air to the burner. k is the burner; it consists of
a number of perforated tubes radiating from a central supply pipe; lis
the second casing of bell-like form which compels the heated gases from
the burner after they have passed under the bottom and up in close
proximity to the sides of the boiler to descend to a lower level than that
at which the burner is placed before they can escape beneath its lower

page_text: edge, and ascend to the chimney m which is fixed at the top of the outer
casing o. p is the wooden lagging, and q, the space in which non-
conducting material is enclosed; "is the top or cover plate; 8 is the
supply cistern; t is the float which opens the supply valve; u is wooden
lagging enclosing a space w to receive non-conducting material. There
is a steam pipe, not shown in the Drawing, which connects the steam
In the
space of the boiler with the upper part of the supply cistern 8.
case of open coppers instead of making the casing 7 of bell form we fix
its upper edge to the top or upper part of the copper, and instead of
making the outlet casing pass over the entire surface of the inner casing
we narrow it into one, two, or more small flues.
We claim as respects this part of our Invention the arrangement
whereby the boiler is enveloped in a current of hot gases ascending from
a gas burner, and whereby the heated gases are caused to descend (after
they have risen nearly to the top of or completely encircled the boiler)
to about the level of the burner before they can reascend to the chimney,
and whereby the whole is surrounded with non-conducting material, all
substantially as described.
The non-conducting material which by preference we employ is such
as is described in the Specification, No. 2833, in the year 1874.
Sometimes, as is shewn in Figures 6 and 7, we insert into the bottom
of the boiler horse-shoe shaped tubes in number proportionate to the size
of the bottom of the boiler. We prefer the tubes to be of such a length
and diameter as will make their aggregate surface equal to the whole
surface of the boiler. These tubes are intended for the heated air and
products of combustion from the gas burner beneath the boiler to pass
through them, and they are so fixed that their entrances are ranged in
a circle round the centre of the bottom of the boiler and their exits in a
circle near the edge of the bottom of the boiler. And in order to ensure
the heated air passing into the entrances only of the tubes we fix a short
tube or curtain touching the bottom of the boiler between their inlets
and outlets, and we carry this curtain downwards so as to prevent any
admixture of the inlet air for combustion of the gas and the outlet
products of combustion.
The burner we make in rays, star-shaped, each ray being screwed into
a central chamber, and we make the whole either flat to take the form
of the bottom of the boiler or otherwise. Each of these rays has a short

page_text: chimney running its whole length with the spaces between each ray
stopped to prevent the passage of air. The whole combined burner we
enclose in a tube or curtain open at the bottom for the admission of air.
By this arrangement no air can pass through the flue tubes in the boiler
excepting it first passes through or in close proximity to the flames of
the burning gas.
We do not confine ourselves to the ray form, as we sometimes make it
take the gridiron form or other shapes.
We claim as respects this part of our Invention the arrangement of
the boiler tubes, the curtain, and the gas burner tubes with their
chimnies, substantially as described.
In witness whereof, we, the said John Chapman Peacock and
Thomas Rudkin, have hereunto set our hands and seals, this
Thirteenth day of August, in the year of our Lord One thousand
eight hundred and seventy-five.
JOHN CHAPMAN PEACOCK. (L.s.)
THOMAS RUDKIN.
(L.S.)