IMPROVEMENTS IN THE APPLICATION OF HEAT FOR BAKING AND DRYING PURPOSES, AND IN THE GENERATION OF STEAM
Year: 1853

page_text: LETTERS PATENT to William Hickson, of Carlisle, in the County of
Cumberland, Gentleman, for the Invention of "IMPROVEMENTS IN
THE APPLICATION OF HEAT FOR BAKING AND DRYING PURPOSES, AND IN
THE GENERATION OF STEAM"
Sealed the 29th September 1858, and dated the 8th August 1853.
PROVISIONAL SPECIFICATION left by the said William Hickson
at the Office of the Commissioners of Patents, with his Petition,
on the 8th August 1853.
Spe
I, WILLIAM HICKSON, of Carlisle, in the County of Cumberland, Pro
Gentleman, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE APPLICATION OF HEAT FOR BAKING AND DRYING
PURPOSES, AND IN THE GENERATION OF STEAM," to be as follows:-
This Invention relates to a new construction of oven for baking,
cooking, and drying purposes, and to the principle of the application of
the heat used therein for the purpose of generating steam, and consists
in the employment of a series of spiral ovens composed of porous stone,
earthenware, glazed or otherwise, iron or other suitable substance,
surrounding a central well or heating chamber. Between each coil of

page_text: the series of the above-mentioned ovens is formed a flue for the circu-
lation of the heat, such flue or flues forming a communication between
the central heating chamber or well herein-before mentioned and an out-
side flue or outlet which forms the outer boundary of the spiral ovens.
By another arrangement the flues between each series or coils of
ovens follows the course of the oven itself, and are closed laterally.
These flues are divided longitudinally by a diaphragm of any suitable
material, by which means a double current of heated air is allowed to
pass through them, such currents traversing in opposite directions, the
ingress being from the upper and lower portions of the heating furnace
or furnaces. The heated air in passing to and from the spiral flues
herein-before described is made to traverse a series of vertical
boiler tubes arranged in the heating furnace or furnaces. These por-
tions of the ovens which are subjected to the direct action of the flame
are protected by a water space or chamber which forms part of the
steam generator herein-after described. The cleaning of the first-men-
tioned flues is effected by a wire brush or scraper, which is entered
through splayed door frames suitably arranged for the purpose in the
external casing of the series of ovens. The spiral flues are cleaned by
the same apparatus, which is entered by the opening or temporary
removal of parts of the external casing of the flues. The interior of the
ovens are lighted by a series of sliding doors which open into the
central heating chamber. The heat of the same is equalized or regu-
lated by a series of dampers acted upon by a number of self-acting
heat regulators. These regulators consist of a column of mercury
enclosed in a metal tube, and acting upon a piston in a cylinder, which
piston is connected with the regulating dampers. A sliding indicator
connecting the piston with the dampers serves to effect and maintain
any specific temperature required. An endless travelling chain is
made to traverse along and through the entire length of each spiral
oven, actuated by chain pulleys suitably arranged, the speed of each
chain being regulated by conical drums. A slot in each alternate
link of the chain serves to connect and carry the biscuit paus through
the oven. Ovens of the above construction may be obviously made
either portable or otherwise. In the arrangement first described an

page_text: iron or other metal chamber is made to enclose the entire series of 1
ovens; it is connected with tubular swivel danpers, and fitted with
tubes to protect those portions of the ovens more immediately acted
upon by the flame, as well as to give direction to the draught, thereby
constituting a steam generator. Another arrangement of generator
consists of a water space or chamber which forms the central heating
chamber or well, and protects that part of the oven immediately acted
upon by the flame. In this boiler are arranged a series of vertical
tubes, through which the heat passes to and from the series of spiral
flues. The furnace is supplied with fuel in each arrangement, and
this supply is regulated by a pair of toothed or fluted rollers fitted with
a hopper immediately above the furnace, such rollers gearing together,
and being driven by a belt or other suitable mechanical arrangement,
regulated by one or more heat indicators similar to the one herein-
before described. The consumption of the smoke and cinder in these
furnaces is effected by the employment of a double series of fire bars,
one above the other, from end to end. The burnt cinders which fall
from the upper bars serving during the completion of their consumption
on the lower bars to consume the smoke given off by the coals on the
unner bars.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Hickson in the Great Seal Patent Office,
on the 8th February 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, s
WILLIAM HICKSON, of Carlisle, in the County of Cumberland, Gentle-
man, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighth day of August, in the year
of our Lord One thousand eight hundred and fifty-three, in the
seventeenth year of Her reign, did, for Herself, Her heirs and succes-
sors, give and grant unto me, the said William Hickson, Her special
license that I, the said William Hickson, my executors, administrators,
and assigns, or such others as I, the said William Hickson, my execu-

page_text: tors, 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 APPLICATION OF HEAT FOR BAKING AND DRYING PURPOSES, AND IN THE
GENERATION OF STEAM," upon the condition (amongst others) that I, the
said William Hickson, by an instrument in writing under my hand and
seal, 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 I, the said William Hickson, do hereby de-
clare the nature of my said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and
by the following statement, reference being had to the accompanying
Drawings, and to the letters and figures marked thereon, that is to say:
My said Invention relates to a new construction of oven for baking,
cooking, and drying purposes, and to the principle of the application of
the heat used therein for the purpose of generating steam, and consists
in the employment of one or more boilers or steam generators (located,
say, in the cellar of a suitable building), having one or more furnaces,
cach furnace fitted with two sets of fire or grate bars. The upper bars
are somewhat shorter than the length of the furnace, whilst the lower
ones extend the whole length of the furnace or up to the bridge.
Between these two sets of fire bars is fitted a series of angular (or
other suitably shaped) water spaces, forming a kind of network, with
rectangular openings through which the cinders or partially consumed
fuel pass to the lower as they or it falls from the upper series of bars.
A communication is formed between the bottom and top furnaces by a
series of lateral passages, which admit the hot air from the lower into
the upper furnace, and thereby facilitating the combustion of the smoke
and unconsumed gases given out by the as yet unconsumed fuel. The
supply of fuel to each furnace is effected by an archimedian screw

page_text: forming a communication between a hopper (ranged immediately above S
the furnace doors) and the interior of the furnace, under which (the
screw) are two toothed or fluted rollers revolving in contrary directions
which serve to crush or break any large lumps of coal. The coal is
delivered to said hopper from a convenient well or pit by an endless
chain carrying a number of elevating buckets, and driven by chain.
pullics from the same prime mover as the screw and rollers, the latter
geared together, and the whole driven simultaneously by a suitable
arrangement of mechanism, thrown in and out of gear (thereby regu-
lating the supply of fuel) by a self-acting heat indicator of the follow-
ing form: A tube containing a quantity of mercury projects into
the steam chamber, and is connected with a cylinder (horizontal) on
the outside of generator, being open at one end; hence, the alternate
pressure of the atmosphere or mercury upon the piston, said piston
having a slotted dye through which the driving belt passes. Imme-
diately above the aforesaid steam generators (say, on the basement
story,) are arranged a series of spiral ovens on suitable supports, form-
ing a central well or heating chamber, constructed of porous stone, fire-
clay, glazed or otherwise, iron or any other suitable material, each series
being at some distance above the other; the intermediate spaces closed
or partially closed laterally form the flues (the said flues being divided
longitudinally by a diaphragm of any suitable material, where or when
the several series of ovens are required to be heated to so many
different temperatures). The hot air from the aforesaid several fur-
naces is received into the said central heating chamber, whence it
passes into the aforesaid flues, thence into outer lateral flues, and thence
into larger vertical flues. At the upper extremity of these said ver-
tical flues (and midway also, should it be found that the heat or hot
air rather inclines to the lower than the higher flucs.) are swivel
dampers, acted upon by self-acting heat regulators similar to that hercin-
before described, excepting that the column of mercury penetrates the
ovens or flues, as the other does the steam chamber. The aforesaid
central chamber is closed at the top, with the exception of a small space
occupied by a damper (and designed also to serve as a manhole), acted
upon by a self-acting heat or steam indicator in connection with the

page_text: steam chamber or generators, which indicator acts in conjunction with
that regulating the supply of fuel. By this arrangement steam may
be got up and maintained in the generators without, if need be, heating
the ovens or heating said ovens beyond the degree of heat required.
The outer and inner sides of the ovens are made double, and formed
with an internal air space for the purpose of checking the intensity
of the heat in the central heating chamber, and preventing the undue
action of the cold air from without, the heating surface by these means
being confined as much as may be to the top and bottom of the ovens.
Through the entire length of each spiral oven is passed a separate end-
less chain carrying on suitable trucks, carriages, or pullies a series of
circular oven pans ranged in close succession. Said oven pans, as they
traverse the ovens, and from friction against the inner side of the oven,
receive a compound rotatory motion; that is, the oven pans revolve
upon their own axis, and revolve also round or traverse in a spiral
direction the circumference of the central chamber or well (any
number of times). The axis of each pan is a vertical pin fixed upon
the chain or truck, &c. The ingress or entrances to the different
ovens are situated, say, at the top of the building, and are in the same
horizontal plane, but situated at different points on the circumference
of the circle, if the building is round, but if the building is rectangular
they are at each corner. The ovens wind round the interior of the
building in the form of a four-threaded screw, and open at the bottom
at diametrically opposite portions in the building to their entrances; an
inclined plane (also a flue) projecting beyond the external casement of
the building forms a communication with or connects the ingress with
the egress of the several oveus; these are to facilitate the continuous
course of the endless chains, and to keep the oven pans whilst outside
of the oven at an even temperature. The biscuits being cut into
proper shape (by, say, four ordinary machines, say, one machine to each
spiral oven or endless chain,) fall directly from the machines on to said
oven pans, which pass under the machine (which, it is supposed, are on
the first floor of the building), and carried thence through the oven on
to the basement floor or packing room, the biscuits being baked during
their transit. The chains, &c. are driven by chain pullies from the

page_text: same moving power which actuates the biscuit machine, and both are >
regulated as regards speed by a series of conical drums, &c. The
interior of the several ovens are lighted by a series of sliding doors and
eye pieces, the former opening through the internal casement into the
heating chamber, the latter through the external casement of the ovens.
Provision is made by a series of doors in the flues for their being swept,
when requisite.
Figure 1, on Sheet 1, of my Drawings represents a complete ex-
ternal elevation of my improved baking and steam generating appa-
ratus; Fig. 2, is a corresponding plan of the same; Figs. 3, and 4, are
separate details of the biscuit carrying chain; and Figs. 5, and 6, are
details of one of the heat regulators. Fig. 1, on Sheet 2, of the
Drawings represents a vertical section of the ovens and steam gene-
rator, taken through the centre. Fig. 2, is a horizontal section of
the same, with portions of the external spiral flues broken away;
Figs. 3, and 4, are details of the furnaces; and Figs. 5, and 6, are
separate letails of the feeding or fuel supplying rollers and gearing.
A, A, is the body or external casing of the steam generator composed
of iron plates rivetted together similar to an ordinary boiler; the form
of this generator is that of a vertical cylinder, with 4 furnaces B, B,
arranged diametrically opposite each other. Each furnace is fitted
with two sets of grate bars C, C', after the system patented by
Mr. Stevens on or about the
The
upper bars C, are rather shorter than the length of the furnace, whilst
the lower ones C', extend the whole length of the furnace, reaching to
the bridge D. Between these two sets of bars is fitted a series of
angular or other suitably shaped water spaces E, E, forming a kind
of network, with rectangular openings F, through which the cinders or
partially consumed fuel pass through as they fall from the upper bars
to the lower oues. A communication is formed between the bottom
and top furnaces by the series of lateral passages F', which admit of
the entrance of the hot air from the lower furnace into the upper one.
and thereby greatly facilitate the combustion and consumption of the
smoke and unconsumed gases given out by the as yet unconsumed
fuel. The system of water spaces and furnaces hercin-before referred
day of
.

page_text: to is shewn in transverse section at Fig. 3, and in corresponding
plan at Fig. 4, which is a horizontal section of the furnace taken
above the water spaces. The bridge 1), is of a hemispherical form, and
answers the same purpose for all the four furnaces which radiate from
it. The supply of fuel to each furnace is effected by an archimedian
screw G, and a pair of grooved or fluted rollers H, H', which are
driven by the driving belts I, I, which pass over the upper and lower
pulleys J, and K. The lower pulleys K, are keyed on to the ends of
the screw shafts, which carry also a spur pinion L, gearing into another
pinion M, on the shaft of the roller II. The shaft of the roller II',
carries a second pinion N, which gears with the pinion O, fast on the
shaft of the roller H. By this means both rollers are made to revolve
in contrary directions, and thereby break the larger pieces of coal as
they pass between them. The coal is fed into the hoppers P, by the
endless bucket chains Q, which elevate it from suitable coal pits. As
fast as the coals fall into the hoppers it is withdrawn by the screws G,
which convey it over the top of the feeling rollers. The whole of the
feeding mechanism is driven by the driving belts R, and fast and loose
pulleys S, S'. Each belt is governed by a heat regulator, for which
purpose it is passed through a slotted dye T, in the end of a small
piston rod U, which is fitted with a piston working accurately in a
cylinder V, connected with a pipe projecting inside the boiler, as shown
in detail, Fig. 5, Sheet 1, which represents a heat regulator, herein-
after described, fitted with a vertical instead of a horizontal cylinder, as
in the present case. The pipe projecting into the boiler is filled with
mercury, or partially filled, as the case may require, so that when
the temperature of the steam in the boiler becomes too high the
mercury expands, and by forcing out the piston and rod U, the
driving belt R, is pushed from the fast pulley S', on to the loose
pulley S, thereby throwing out of gear the feeding mechanism, and
consequently stopping for a time the supply of fuel to the furnaces.
Where the temperature, however, diminishes the external atmospheric
pressure on the surface of the piston forces it back again, and thereby
replaces the driving belt R. on the fast pulley S', when the feed re-
commences. These feeders are all driven by convenient mechanism,

page_text: which I have not considered necessary to delineate in the Drawing. S
The flame and heated air from the four furnaces unite in the central
vertical flue W, and ascend the short chimney X, from which it enters
the interior of the well or open space Y. The whole of the baking
apparatus or oven is supported by the girdlers Z, Z, which are carried
on suitable supporting girders and columus arranged round the steam
generator in any convenient form. The internal chimney X, has a
series of apertures a, formed round its circumference to allow the flame
and heated air to escape through them laterally as well as through the
top of the chimney, as shewn by the arrows. The heat then passes in
the direction of the arrows through the lateral openings b, round the
interior of the main well or central chamber, and enters the flues c. from
which it passes through the smaller lateral openings d, into the small
side flues e. These flues are composed of fire-clay, slate, or stone, and
serve to heat the four continuous spiral ovens or baking chambers f,
the sides of which, it will be observed on reference to the Drawings,
are made double, and formed with an internal air space g, for the pur-
pose of checking the action of the cold air from without, and checking
the intensity of the heat in the interior of the oven, which would other-
wise burn the biscuits or other articles under the process of baking.
The top and bottom of each of these ovens is formed by the stone, slate,
or fire-clay divisions h, which constitute the top and bottom of the
intermediate flucs c. These flues, as well as the small lateral flues e,
are spiral and continuous like the ovens, but are divided into separate
compartments or lengths by the fire-clay division pieces i, i, shewn in
dotted lines in Fig. 2, on Sheet 2, of the Drawings. The heated
air and flame passes through the series of flues c, into the smaller flues e,
which open into the four vertical flues j, j. From these last flues the
heat passes along the horizontal flues k, k, on the top of the building
into the chimney 1, which is situated over the centre of the well Y.
The heat of the ovens is regulated by the self-acting dampers m, m,
fitted to the top of each of the four vertical flues j. j. These dampers
are actuated by the heat regulators n, n, the mercury pipes of which
are fitted into the vertical flues before mentioned. They are constructed
on precisely the same principle as the one shewn in detail at Fig. 5,

page_text: the adjusting coupler or bridle piece o, Fig. 6, being graduated or
divided, in order that the regulator may be set to any required heat by
shortening or lengthening the connexion between the piston p, and
the damper to be acted upon. The central damper 7, is actuated by
the heat regulator r, attached to the boiler, and is made to open or shut
according to the temperature of the steam. When the temperature of
the steam rises too high the piston in the regulator r, is elevated, and
closes thereby the main damper q, which stops or checks the draught,
and consequently diminishes the action of the furnaces. This movement
will occur simultaneously with the disengagement of the feeding gear
herein-before described. The weight of the rods of these several heat
regulators to be neutralized by suitable counterbalance weights suitably
arranged. The entrances s, s, to the different ovens are situated at
the bottom of the building and immediately over the steam gene-
rator, and are all in the same horizontal plane, but situated at different
points in the circumference of the circle if the building is round, but
if the building is rectangular they are arranged to enter at each
corner; they wind round the interior of the building in the form of a
four-threaded screw, and open out at the top at diametrically opposite
portions in the building to their entrances, as shewn by the Drawings.
The outside flue of each oven is continued beyond the side of the case-
ment of the building, as at t, t, connecting thereby the entrance and
exit of each separate oven. These outside flues serve to prevent the
endless chains of biscuit pans . n, from cooling during their passage
along the outside of the building. The pans are composed of fire-clay,
iron, or stone, made into trays of a circular form, with or without a
flange, as shown by the details, Figs 3, and 4, on Sheet 1, of the
Drawings. The circular pans, are fitted to revolve loosely upon the
links of the endless carrier chain, each alternate link being fitted with
a vertical pin v, passing through the centre of each pan, which revolves
freely round its centre during the progress of the chain, each pan
acting as a wheel or antifriction pully by rolling along the raised
portion w, on the inside edge of the flue t, t, or the inner casement of
the building. There are four of these chains, one to each oven,
traversing internally throughout the entire length of the helix, the

page_text: direction of their movement being shewn by the arrows in Fig. 2, s
on Sheet 1, of the Drawings. The mechanism for actuating each
chain consists of a vertical driving shaft a, working in footstep bear-
ings y, and fitted with a series of conical driving pulleys z, at its upper
extremity, a belt connected with any convenient prime mover giving
the requisite movement. A notched pulley or wheel 1, is keyed on to
each vertical shaft, such wheel gearing into the studs of the chains,
and consequently giving the required traverse. As fast as these
pans u, u, enter the top or bottom of each oven, according to the
direction in which the chain revolves, they may be supplied with paste
or dough already cut into proper shape by an ordinary biscuit making
machine situated at each entrance. In order to facilitate the cleaning
of the top horizontal flues k, k, a small door 2, turning on hinges 3, is
situated at the top of each of the vertical flues j, j, and another set of
horizontal doors 4, turning on the linges 5, admit of the cleaning
of the vertical flues. The soot cleared or pushed down from above is
removed through the bottom hinged doors 6. A series of sliding
doors 7, are arranged spirally around the ovens, in order that the
attendant may examine the state of the biscuits during their progress
through the ovens. For this purpose a series of sliding windows or
light apertures 8, (Fig. 2, Sheet 2,) are fitted inside the central
well Y, such windows being open or closed by the rods 9, which
project outside the building.
I may observe that I do not confine myself to any particular form or
construction of building, to a particular number of spiral ovens in onc
series, nor yet to the sizes shewn in the accompanying Drawings, these
being altered or determined upon as circumstances shall require.
I also propose constructing ovens on the same spiral principle of a
rectangular transverse section; in such case a carrier wheel is fitted at
each corner inside the ovens in order to guide the endless chains
during their ouward progress. By another arrangement I construct
ovens on an horizontal plane, but one above the other, the intermediate
flues being partially divided by a number of partitions of a suitable
material, so arranged as to give the hot air a zigzag direction, thereby
spreading it over the whole top and bottom surface of the ovens.

page_text: Each oven may also be divided by internal divisions of a curved shape,
and at each extremity of said divisions is a carrier wheel giving
direction to the endless chains, as they also pass to and fro' in said
ovens in a zigzag direction, the curved divisions or otherwise friction
rollers giving to each oven pan a rotatory motion, as before described.
The hot air in this arrangement passes from side to side, while
the chains, &c. pass from end to end, or in an opposite or cross
direction. The steam generator may either be below or on the
same horizontal plane; in the latter shape I propose to apply
it to sea-going vessels, the steam power being employed to propel,
work cranes, and hoist sails, &c., in which shape also it may be
suitably applied to ships of war, as the whole is capable of being
arranged or constructed below the water line. By another arrange-
ment I construct ovens of a spiral character by an archimedian screw
having a tubular axle or shaft and ranged vertically. The thread or
worm of the screw being hollow to serve as a flue, and the tubular axle
as the feeder, &c. The whole revolve within a well or external case-
ment of suitable material. The biscuit pans are by the revolving of
the screw let down in a perpendicular direction, a pin and slot, the
former projecting from the pan, and the latter, in the shape of a
groove, from top to bottom of said casement, preventing the biscuit pan
being moved in any other direction. The circumference of the well is
grooved in a similar manner at every pan length, so that the worm may
be completely charged with biscuits, each revolution leaving the top
course ready for a second supply. When the pans arrive at the
bottom of the well their contents will have been baked. The pans also
may be circular and be given a rotatory motion by friction rollers, and
a steam generator may be applied to this plan also, say, in the shape of
an external casement. The plan illustrated in the accompanying
Drawings is capable of many minor modifications, such as filling the
central chambery, with a steam generator, having a number of vertical
tubes as a passage for the hot air to the flues, which in this case would
traverse the flues from top to bottom spirally. The flues c, may also be
wholly closed laterally, and the hot air given a circuitous direction,
making one or more revolutions. In this case the chamber y, would

page_text: be divided diametrically into two compartments, the hot air passing into Sp
the flues from one, and escaping thence into the other, the latter having
its exit in the chimney 7. The lateral flues e, may be also located in
the centre of the flucs e, having an opening at each side. In this case
the hot air would flow into it from both sides of the ovens by the
addition of another outer casement, the intervening space forming a
flue and a communication made therewith from the chamber y, under-
neath the bottom of the ovens, the air finally escaping as at present
shewn. The same principle of multiplying ovens may be applied to
iron kitchen ranges or smaller ovens or stoves used for domestic pur-
poses, by having each shelf perforated or inflated so as to allow a
current of hot air to pass through cach shelf, and in each compartment
or oven I arrange a turntable or revolving shelf, revolving loosely upon
a fixed vertical pin, and cach shelf so arranged actuated by a vertical
friction roller pressing against the outer edge or circumference of cach
and all of said circular shelves, said friction pulley or roller actuatel by
clockwork, &c. &c.
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 may 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 main 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 machinery,
apparatus, or means for baking or cooking biscuits and other articles
of food.
Second, the combination of a steam generator and baking apparatus
wherein the heat employed for raising the steam is economised and
further employed in heating the ovens, or vice versa.
Third, the application and use of the heat regulators for checking
the supply of fuel to the furnaces and actuating the dampers, as herein-
before described.

page_text: Fourth, the application and use of an endless chain of biscuit pans
constructed in the manner herein-before described.
Fifth, the application and use of spiral or inclined and horizontal
zigzag ovens and flues, as herein-before described.
Sixth, the application and use of the angular water spaces arranged
or disposed between the two sets of furnace bars in the manner and for
the purpose herein-before described.
Seventh, the system or mode of supplying the upper furnace with air by
means of the lateral pipes or tubes F, hercin-before described in. refer-
ence to Figs 3, and 4, on Sheet 2, of my Drawings.
In witness whereof, I, the said William Hickson, have hereunto
set my
hand and seal, the Seventeenth day of January, in the
year of our Lord One thousand eight hundred and fifty-four.