IM. PROVEMENTS IN AND APPLICABLE TO OVENS, BOILERS, AND OTHER APPARATUS IN WHICH HEAT IS EMPLOYED
Year: 1867

page_text: LETTERS PATENT to William Spence, of S, Quality Court, Chancery Lane,
in the County of Middlesex, Patent Agent, for the Invention of "IM.
PROVEMENTS IN AND APPLICABLE TO OVENS, BOILERS, AND OTHER APPARATUS
IN WHICH HEAT IS EMPLOYED."-A communication from abroad by Alfred
PROVISIONAL SPECIFICATION left by the said William Spence at the
Office of the Commissioners of Patents, with his Petition, ou the
3rd October 1867.
I, WILLIAM SPENCE, of 8, Quality Court, Chaucery Lane, in the County
of Middlesex, Patent Agent,do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN AND APPLICABLE TO OVENS, BOILERS, AND OTHER APPARATUS
IN WHICH HEAT IS EMPLOYED," (being a communication to me from abroad by
Alfred Charles Joly de Marval, of Paris, in the Empire of France,) to be as
follows:-
This Invention has for its object the economy of fuel and labour with the
maintenance of an increased regularity of temperature, and consists in the
adaptation and application to ovens, boilers, and other apparatus in which
heat is employed of an endless tube disposed in a coil or coils in such a
Price ST

page_text: manner as to be capable of receiving heat from a furnace or fire-place, and
through which heated water is caused to circulate.
The Invention when applied to ovens consists of an endless tube in the
form of three coils one above another, the lowest coil being enclosed in a
small fire-place or chamber heated by any convenient means, and supplied
with water at the bottom through a vertical pipe descending from the upper
part of the apparatus, such pipe being suitably closed as required. This
lower coil terminates in a pipe communicating with a second coil, which
forms the roof of the oven, and this second coil terminates in a branch pipe
communicating with a third coil underneath the bed of the oven, which is
perforated with small holes for the ready passage of heat into the chamber or
space between the two last-mentioned coils; this third coil terminates in a
pipe or tube which communicates with the lower part of the first coil. By
this arrangement the three coils form one endless tube for the passage and
circulation of water, which is constantly receiving fresh heat from the furnace
or fire-place and transmitting it through the coils, so as to raise and maintain
the temperature in the oven as required. A compensator or safety valve is
applied to the upper part of the pipe of communication between the first and
second coils, and a pressure indicator is also used.
The Invention when applied to apparatus for calcining or roasting plaster
of Paris, and for similar uses, consists in an endless tube or coil inserted in a
chamber or space formed in brick work, such tube or coil communicating
at the outer end with a heating coil by means of a pipe through which the
heated water is caused to ascend, and at the centre by means of a pipe through
which the water is caused to return to the heating coil. The endless tube or
coil extends over the whole surface of the bed of the chamber, and is sur-
rounded by an endless apron carried over a roller at each end of the coil, one
of which rollers is driven with a slow motion. The plaster to be calcined or
roasted is fed on to the apron through a hopper at one end of the apparatus,
and discharged at the other end thereof.
And when the Invention is applied to a steam boiler, there is a vertical
extension of the boiler inserted in brickwork, and surrounded by a heating
coil in a flue formed in the said brickwork, the heat passing into such flue
from a furnace. One end of the heating coil communicates with a coil or
coils in the steam space of the main boiler, and thence with another in the
body of water therein, and there is a return communication with the heating
coil; a compensator or safety valve is applied to the coil in the steam space
of the boiler. A feed pump may be connected with a branch pipe to the
endless tube, in order to raise the quantity of water required in a given time,

page_text: such pump having no reciprocating parts but merely admitting water into the
barrel of the pump by forming a vacuum therein, and allowing it to pass out
through a pipe leading to the point required. The pipes for the admission
and exit of the water are respectively furnished with valves, and there is a
safety valve at the top of the pump barrel.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Spence in the Great Seal Patent Office on the
3rd April 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
SPENCE, of 8, Quality Court, Chancery Lane, in the County of Middlesex,
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Third day of October, in the year of our Lord
One thousand eight hundred and sixty-seven, in the thirty-first year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said William Spence, Her special license that I, the said William Spence, my
executors, administrators, and assigns, or such others as I, the said William
Spence, my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during the
term therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN AND APPLICABLE
TO OVENS, BOILERS, AND OTHER APPARATUS IN WHICH HEAT IS EMPLOYED," being
a communication from abroad by Alfred Charles Joly de Marval, of Paris,
in the Empire of France, upon the condition (amongst others) that I, the
said William Spence, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what inanner
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 Spence, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the Drawings hereunto annexed, and to the
letters and figures marked thereon (that is to say):-

page_text: This Invention of "Improvements in and applicable to Ovens, Boilers, and
other Apparatus in which Heat is employed, "has for its object the economy of
fuel and labor with the maintenance of an increased regularity of temperature,
and consists in the adaptation and application to ovens, boilers, and other
apparatus in which heat is employed of an endless tube disposed in a coil or
coils in such a manner as to be capable of receiving heat from a furnace or
fire-place, and through which heated water is caused to circulate.
The Invention when applied to ovens consists of an endless tube in the
form of three coils one above another, the lowest coil being enclosed in a
small fire-place or chamber heated by any convenient means, and supplied
with water at the botton through a vertical pipe descending from the upper
part of the apparatus, such pipe being suitably closed as required. This lower
coil terminates in a pipe communicating with a second coil, which forms the
roof of the oven, and this second coil terminates in a branch pipe communi-
cating with a third coil underneath the bed of the oven, which is perforated
with small holes for the ready passage of heat into the chamber or space
between the two last-mentioned coils; this third coil terminates in a pipe or
tube which communicates with the lower part of the first coil. By this
arrangement the three coils form one endless tube for the passage and circula-
tion of water, which is constantly receiving fresh heat from the furnace or
fire-place and transmitting it through the coils, so as to raise and maintain
the temperature in the oven as required. A compensator or safety valve is
applied to the upper part of the pipe of communication between the first and
second coils, and a pressure indicator is also used.
The Invention when applied to apparatus for calcining or roasting plaster
of Paris, and for similar uses, consists in an endless tube or coil inserted in a
chamber or space formed in brickwork, such tube or coil communicating at
the outer end with a heating coil by means of a pipe through which the heated
water is caused to ascend, and at the centre by means of a pipe through which
the water is caused to return to the heating coil. The endless tube or coil
extends over the whole surface of the bed of the chamber, and is surrounded
by an endless apron carried over a roller at each end of the coil, one of
which rollers is driven with a slow motion. The plaster to be calcined or
roasted is fed on to the apron through a hopper at one end of the apparatus,
and discharged at the other end thereof.
And when the Invention is applied to a steam boiler there is a vertical
extension of the boiler inserted in brickwork,and surrounded by a heating coil
in a flue formed in the said brickwork, the heat passing into such flue from a
furnace. One end of the heating coil communicates with a coil or coils in

page_text: the steam space of the main boiler, and thence with another in the body of
water therein, and there is a return communication with the heating coil; a
compensator or safety valve is applied to the coil in the steam space of the
boiler. A feed pump may be connected with a branch pipe to the endless
tube in order to raise the quantity of water required in a given time, such
pump having no reciprocating parts but merely admitting water into the barrel
of the pump by forming a vacuum therein and allowing it to pass out through
a pipe leading to the point required. The pipes for the admission and exit
of the water are respectively furnished with valves, and there is a safety valve
at the top of the pump barrel.
Having thus stated the nature of the said Invention, I will proceed to
describe more particularly in what manner the same is to be performed by
reference to the accompanying Drawings.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 is a vertical section and Fig. 2 a horizontal section (in the line 1, 2,
of Fig. 1) of an oven.
A is the lowest coil surrounding the brickwork M and heated by the
furnace G, but it may be heated as required by any other convenient means.
This coil being the first of the series is filled with water at the top by ineans
of a tube a hermetically closed by a screw stopper b. B is the second coi!
which forms the roof of the oven and communicates with the coil A by the
pipe c, to the last spiral of which it is connected by a screw joint ; C is the
third coil placed underneath the bed of the oven (which is perforated to allow
heat to pass through it), and communicating by the branch pipe d with the
coil B. The centre part of the coil C communicates by a pipe e with the
lower part of the coil A. It will hence be seen that by means of this arrange-
ment the three coils formone endless tube, which is completely filled throughout
with water from the vertical tube, through which water is supplied, to the
last branch e, which returns to the originally heated coil. When the furnace
is lighted the water in the coils is caused to expand therein by the action of
the heat, and a continuous and very rapid circulation is produced, which,
taking the direction of the highest part of the apparatus and acquiring a
constant accession of force from the heat of the furnace, is caused to transmit
to the interior of the oven a heating power proportioned to the temperature
attained in the furnace or to the extended surface of the tubes.
For bakers' oveus, taken as the present example, the baking is effected
more rapidly than in ovens of the ordinary construction by the more direct
action of the heat on the bread. The economy in fuel resulting from several

page_text: experiments appears to be not less than sixty per cent., besides a considerable
saving of labor. D is a compensator or safety valve applied to the upper
part of the pipe e to prevent mischief from the expansion of the water during
the work; m is a pressure indicator. The tubes are connected by sockets
with right and left passages in them, also all sudden bends are avoided in
order to afford the requisite freedom of circulation for the water through
them.
Figures 3 and 4 represent in vertical and horizontal section an oven
intended for calcining or roasting plaster of Paris residues by a continuous
process of heating, thereby avoiding the cooling due to the ordinary inter-
rupted process. The oven is entirely closed, and has only one circuit, which
is maintained in the coil B, fed by the coil A, in contact with the furnace
arranged similar to that above described. The connection of the coil B with
the coil A is formined by means of the pipes/and. The coil B, which covers
the whole surface of the bed, is surrounded by an endless apron, which is
caused to advance in the required direction by the action of the gearing p
and p', driven by the pulleys P, P. This apron, which is of the full width of
the oven, is suitably guided by means of rollers, and receives directly all the
heat given out by the coil B (say two hundred degrees, or whatever may be
the temperature employed) as well as that Petained by the crown of the
furnace, which is very low. T is a hopper through which the material to be
calcined or roasted is fed into the oven through a passage c, the opening of
which may be regulated by a valve d, so that the bed of material on the apron
t may not exceed the hundredth part of a "metre "in thickness. The advance
of the apron is calculated so that the material thereon may be completely
calcined or roasted during the time occupied in its traverse of the length of
the oven, it then falls 'hrough the opening o and is withdrawn in the ordinary
manner.
Fig. 5 represents the mode of heating under the Invention as applied to a
boiler for the purpose of obtaining steam dry and superheated without extra
expense. The main body Cof the boiler is provided with a vertical extension
C passing down into the masonry. This extension of the boiler is surrounded
by the coil A heated by the furnace G; this coil communicates by means of a
pipe with one or more coils D arranged in the steam chamber of the boiler.
The coil D represented in the Drawings is put in communication with a third
coil H surrounded by water required to be evaporated, one of the spirals of
which coil returns to the lower part of the coil A by the pipe c.
By this
means a continuous circulation is maintained as in the arrangements herein-
before described, and at the upper part of the coil Dis provided a compensator

page_text: or safety valve D' as before. The heat proceeding from the fire-place G heats
the bottom of the boiler C, then passing along the flue surrounds the coil A
and the boiler extension C'; the water contained in the coil A is quickly
raised to the temperature required, which is transmitted to the coil D, which
dries and superheats the steam generated in the steam generator C; after
having parted with a portion of its heat by passage through the water in the
generator the water of the coil recovers its normal temperature in the spirals
of the coil A.
Various experiments have shewn the practicability of utilizing the heat
from one of the tubes connected to the above-described coils in the preceding
applications without detracting from the regularity of the heating process
under ordinary conditions. This pump, which requires no essential parts
besides three necessary valves, may be a useful auxiliary for ovens and
furnaces by raising without other provision the quantity of water that may be
required for use in a given time. This pump is represented as applied at the
side of the baker's oven, Fig. 1, and connected to the pipe a shewn by red
lines; this pipe, connected to the coils A, B, and C, that is to say, forming
part of the continuous circulation, traverses from end to end the pump body
P, which may be of metal or of wood, and to which is connected the induction
pipe p closed by the stop valve p'; P' is the overflow pipe for the escape of
water in any convenient direction, and is furnished with a weighted valve as
shewn. At the top of the receiver is a valve D, which allows the escape of any
excess of steam or vapor as required; beneath this valve is a plate c for
preventing any sudden blow on the same, as well as any prejudicial effect from
the sudden formation of steam. The heating pipe is surrounded by a pipe
, by which means the pump.ris separated from the body of water precipitated
in the pump P, and thereby renders the application successful.
i
The working of this pump is as follows:-Assuming the heating apparatus
to be at work, and the water precipitated into the body of the pump after the
vacuum has been produced, a portion of this water enters the tube and is
immediately turned into steam. The water escapes by the pipe P!, and the
steam instantaneously produced in the annular space between the pipes & aud
a is rapidly condensed by its contract with the cool sides of the receiver. A
vacuum is thereby produced, and a fresh quantity of water enters, and the same
process is repeated successively.
The advantages of this pump result from the absence of ordinary mechanism,
thereby getting rid of friction and the liability to get out of order. The pump
is entirely self-acting without the need of transmission or cost of setting up.
The additional pipey may serve in case of need for any special supply of the

page_text: tube, especially should there be any reason to fear that the water could not
reach high enough to fill the tube.
Having thus described the nature of the said Invention, and in what
manner the same is to be performed, I would remark that the arrangements
and proportions of the parts of apparatus herein-before described may be
varied without departing from the essential character of the Invention; but
what claim as of the Invention communicated to me from abroad as
aforesaidis notonly the general arrangement of apparatus adapted for heating
ovens and furnaces generally, but also the special combinations of parts by
which the apparatus is rendered practicable and susceptible of application to
various uses. By maintaining a temperature constant and as high as required.
this mode of heating admits of great regularity in the process of baking as
well as an economy of fuel and labor, in various applications of which it is
susceptible.
I also claim as of the Invention communicated to me as aforesaid the pump
working as described merely by the passing of the pipe .r. which forms
part of
the continuous circuit through the reservoir, which contitutes the body of the
pump, and without other essential parts than those described.
In witness whereof, 1, the said William Spence, have hereunto sf my
hand and seal, the Second day of April, in the year of our Lord One
thousand eight hundred and sixty-eight.
Witness,
W. A. JACKSON.
8. Quality Court,
Chancery Lane.
WILLIAM SPENCE. (L.s.)