IMPROVEMENTS IN, CALORIC ENGINES
Year: 1873

page_text: LETTERS PATENT to Charles William Siemens, of No. 3, Great George
Street, Westminster, in the County of Middlesex, for the Invention
of "IMPROVEMENTS IN, CALORIC ENGINES."-A communication from
abroad by Frederick Siemens, of Dresden, in the Kingdom of
Saxony.
PROVISIONAL SPECIFICATION left by the said Charles William
Siemens at the Office of the Commissioners of Patents, with his
Petition, on the 28th June 1873.
I, CHARLES WILLIAM SIEMENS, of No. 3, Great George Street,
Westminster, in the County of Middlesex, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN CALORIC ENGINES," to be as
follows:-
This Invention relates to means of obtaining motive power by the
alternate action of heat and cold on volumes of air or other gascous
fluid contained in a vessel, along with water or other liquid, in such

page_text: manner that the expansion of the gascous fluid and generation of vapour
under the influence of heat alternating with the contraction of the fluid
and condensation of the vapour under the influence of cold effects such
displacement of the liquid as to give a preponderance of weight or
pressure which is utilised as working force. Thus the use of pistons is
dispensed with, the liquid itself acting as a piston, also the heat applied
is economised by the use of regenerators.
The apparatus employed may be of various forms; one form is of the
following description :--Two open tanks or reservoirs are charged to a
certain height with liquid; one of them is kept hot and the other cold.
A vessel open at bottom is immersed in the liquid in each of these
reservoirs in the manner of a gas holder in its tank, so that there is in
each of the two inverted vessels a certain volume of air, vapour, or other
gaseous fluid above the surface of the liquid. A pipe forms a com-
munication between these air spaces, and in the course of this pipe is i
situated a regenerator, which may be an expanded portion of the pipe.
containing wire gauze or other metallic pieces presenting a large
conducting surface, and affording a passage for the gaseous fluid. The
two inverted vessels are made to reciprocate upwards and downwards so
as alternately to increase and diminish the air space in each, but as the
one is hot while the other is cold the air or gas is expanded or mingled
with vapour occupying expanded volume in the hot vessel, and is
contracted or mingled with a smaller volume of vapour in the cold
vessel, which has the effect of causing a displacement of the water or
other liquid in which the vessels are immersed to a greater extent in the
one stroke than in the other, and this displacement reacting in the form
of pressure provides a force which can be utilised as motive power.
The reciprocating vessels are connected to cranks set on a rotating
shaft so as to effect their strokes in suitable succession, and the rotation
of this shaft is itself obtained by the preponderance of the fluid pressure
produced as above described. The air or gaseous fluid in passing along
the communicating pipe from the one vessel to the other passes also
through the regenerator. Thus when it is passing from the hot to
the cold vessel it gives up a portion of its heat to the materials in the
regenerator where the heat remains stored, so that the gaseous fluid in
passing back from the cold to the hot vessel takes up the heat, and thus
the heating power necessary to maintain the difference of temperature
between the two vessels is greatly economised.

page_text: Instead of employing reciprocating vessels as above described a
number of vessels may be combined as compartments of one rotating
vessel set on an inclined axis. A number of these compartments, as for
example the outer ones, may be kept heated while a corresponding
number are kept cold. The lower parts of all the compartments
communicate with each other and contain liquid to a certain height.
Their upper parts containing air, gas, or vapour, communicate one of
the cold compartments with one of the hot in each case by a pipe with
a regenerator, and these communications are so arranged that when the
vessel rotates in one direction the hot compartment is considerably in
advance of the cold compartment with which it communicates. When
therefore the vessel is caused to rotate on its inclined axis in that
direction, the liquid flows by the communications at bottom from one
compartment to the other, but the gaseous fluid being expanded or
vapour being generated in the hot compartments, a portion of the liquid
will always be pressed out of them as they come to the ascending part
of their revolution into the colder compartments, behind them, where the
gascous fluid is contracted or the vapour more or less condensed. There
will thus always be a preponderance of liquid in the compartments
which are in the descending part of their revolution over those which
arc ascending, and this preponderance causes the whole vessel to rotate
with a force which can be utilised as motive power. In this case also
the regenerators serve to economise heating power by taking up and
storing a portion of the heat given off by the gascous fluid in passing
from the hot to the cold compartments, and restoring it to the fluid
when it passes back from the cold to the hot compartments.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Charles William Siemens in the Great Seal Patent
Office on the 24th December 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
WILLIAM SIEMENS, of No. 3, Great George Street, Westminster, in the
County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-eighth day of June, in the year
of our Lord One thousand eight hundred and seventy-three, in the thirty-

page_text: seventh year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Charles William Siemens, Her special
license that I, the said Charles William Siemens, my executors, adminis-
trators, and assigns, or such others as I, the said Charles William Siemens,
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
CALORIC ENGINES," a communication to me from abroad by Frederick
Siemens, of Dresden, in the Kingdom of Saxony, upon the condition
(amongst others) that I, the said Charles William Siemens, my executors
or administrators, by an instrument in writing under my, or their, or
one of their hands and seals, should particularly describe and ascer-
tain 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 Scal
Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that I, the said Charles William Siemens, 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, reference being had to the accom-
panying Sheets of Drawings and to the figures and letters marked
thereon, that is to say :-
This Invention relates to means of obtaining motive power by the
alternate action of heat and cold on volumes of air or other gascous fluid
contained in a vessel along with water or other liquid in such manner
that the expansion of the gaseous fluid and generation of vapour under
the influence of heat alternating with the contraction of the fluid and
condensation of the vapour under the influence of cold effects such
displacement of the liquid as to give a preponderance of weight or
pressure, which is utilized as working force; thus the use of pistons is
dispensed with, the liquid itself acting as a piston; also the heat applied
may be economized by the use of regenerators.
The apparatus employed may be of various forms; one form is of the
following description:-Two open tanks or reservoirs are charged to a
certain height with liquid, one of them is kept hot and the other cold.

page_text: A vessel open at bottom is immersed in the liquid in each of these
reservoirs in the manner of a gas holder in its tank, so that there is in
cach of the two inverted vessels a certain volume of air, vapour, or other
gascous fluid above the surface of the liquid. A pipe forms a com-
munication between these air spaces, and in the course of this pipe may
be situated a regenerator, which may be an expanded portion of the
pipe containing wire gauze or other metallic pieces presenting a large
conducting surface, and affording a passage for the gascous fluid. The
two inverted vessels are made to reciprocate upwards and downwards so
as alternately to increase and diminish the air space in each, but as the
one is hot while the other is cold the air or gas is expanded or mingled
with vapour occupying expanded volume in the hot vessel, and is con-
tracted or mingled with a smaller volume of vapour in the cold vessel,
which has the effect of causing a displacement of the water or other
liquid in which the vessels are immersed to a greater extent in the one
stroke than in the other, and this displacement reacting in the form of
pressure provides a force which can be utilized as motive power.
The reciprocating vessels are connected to cranks set on a rotating
shaft so as to effect their strokes in suitable succession, and the rotation
of this shaft is itself obtained from the preponderance of the fluid
pressure produced as above described: The air or gaseous fluid in
passing along the communicating pipe from the one vessel to the other
passes also through the regenerator, when a regenerator is employed.
In this case when it is passing from the hot to the cold vessel it gives
up a portion of its heat to the materials in the regenerator where the
heat remains stored, so that the gaseous fluid in passing back from the
cold to the hot vessel takes up the heat, and thus the heating power
necessary to maintain the difference of temperature between the two
vessels may be greatly economized.
Instead of employing reciprocating vessels as above described a
number of vessels may be combined as compartments of one rotating
vessel set on an inclined axis. A number of these compartments, as
for example the outer ones, may be kept heated while a corresponding
number are kept cold. The lower parts of all the compartments com-
municate with each other, and contain liquid to a certain height. Their
upper parts containing air, gas, or vapour communicate one of the cold
compartments with one of the hot in each case by a pipe, which may
be furnished with a regenerator, and these communications are so

page_text: arranged that when the vessel rotates in one direction the hot com-
partment is considerably in advance of the cold compartment with
which it communicates. When therefore the vessel is caused to rotate
on its inclined axis in that direct on the liquid flows by the com-
munications at bottom from one coi partment to the other, but the
gaseous fluid being expanded or vapour being generated in the hot
compartments a portion of the liquid will always be pressed out of them
as they come to the ascending part of their revolution into the colder
compartments behind them, where the gaseous fluid is contracted or the
vapour more or less condensed. There will thus always be a pre-
ponderance of liquid in the compartments, which are in the descending
part of their revolution over those which are ascending, and this pre-
ponderance causes the whole vessel to rotate with a force which can be
utilized as motive power. In this case also the regenerators when
applied serve to economize heating power by taking up and storing a
portion of the heat given off by the gaseous fluid in passing from the hot
to the cold compartments, and restoring it to the fluid when it passes
back from the cold to the hot compartments.

page_text: made of different sectional areas, proportional, or nearly so, to the
volumes which air would occupy at the respective temperatures of the
two tanks A and B, allowing in the larger vessel C for additional
expansion of volume due to the presence of vapour along with tho
air.
The action of the apparatus is as follows:- The vessel C descending
from the upper extreme of its stroke while the vessel D is rising air
and vapour displaced from C and cooled in D tends to occupy less
volume than it occupied in C, there is consequently a downward
pressure on both C and D, but that pressure acting on the larger area,
of C gives an unbalanced force, assisting the descent of C, and tending
thereby to turn the shaft E. Again when C is rising from the lower
extreme of its stroke while D is descending the air expelled from D
acquiring heat and becoming mingled with vapour in C tends to occupy.
larger volume than it had in D. There is consequently. an upward
pressure on C and D, but this pressure acting on the larger area of
C gives an unbalanced force, assisting the ascent of C and tending to
turn the shaft E in the same direction. In each revolution of the shaft
there are points where the upward and downward pressures arc in
balance, corresponding to the dead centres of the crank in an ordinary
steam engine. The fly wheel e is intended to carry the machine over
these centres and to give regularity to the movement.
It may be readily understood that two or more pairs of reciprocating
vessels might be arranged to act on the same crank shaft, or on a shaft
coupled or connected to it, so as to sub-divide the irregularities of
action, as in ordinary coupled engines. The effect of the regenerator f,
when it is applied, is to absorb a large portion of the heat from the air
passing through it on its way from C to D, and to restore in great
measure the heat so absorbed to the air in passing back from D to C;
thus effecting an economy in the heating power applied to the tank A,
or saving its liquid contents from being so much cooled and the contents
of B from being so much heated, as would be the case if the air passed
and repassed without interchanging heat with the materials in the
regenerator.
Fig. 5, Sheet II., shews a side clevation of another arrangement of
the improved caloric engine; Fig. 6 is a vertical section and Fig. 7
T

page_text: vessels A and A¹, the inner of which A is kept cool and the outer A¹
is heated. Each vessel is divided by partitions a and a¹ into a number
of compartments 6 and 6¹. The partitions are only formed in the upper
parts of the vessels, so that the compartments of each vessel com-
municate freely with each other at bottom. The upper part of each
compartment 6 of the cold vessel A communicates with the upper
part of one of the compartments 6 of the hot vessel A¹ by a passage R,
which may be arranged as a regenerator. These communications are
so disposed that assuming the vessels to rotate in the direction of the
arrow, Fig. 7, the hot compartment 6' is considerably in advance of the
cold compartment b, with which it communicates. The vessels A, A¹,
are fixed on a shaft C supported in bearings in an inclined position,
as shewn at Fig. 5, and cach vessel is about half filled with water or
other liquid, the upper part as also the communicating pipes being
filled with air or other gaseous fluid. As the vessels revolve in their
inclined position in the direction of the arrow the liquid flows from the
higher to the lower compartments of each vessel, through the com-
munications at bottom. Thus during the descent of each hot com-
partment the air is caused to pass from it into the higher cold
compartment behind it, with which it communicates. Also during the
ascent of each hot compartment the air passes to it from the lower
cold compartment, with which it communicates. In the first case the
hot air entering the cold compartment is cooled and contracted, and
in the second case the cold air entering the hot compartment is heated
and dilated. Owing to this contraction of the air on the one hand
and its dilatation on the other hand a portion of the liquid is always
pressed out of the ascending compartments into those that are
descending, giving to the latter a preponderance, which causes the
vessels to rotate with a force that can be utilized as motive power.
In this case also the effect of regenerators when applied at R, in the
course of the communicating pipes, is to economize heating and cooling
power by permitting an interchange of heat between the materials in
the regenerators and the air which passes them.
Although in the above description air has been mentioned as the fluid
subjected to alternate expansion and contraction, the compartments
might be charged in their upper parts with other gases, also besides
water other liquids might be employed to charge the lower portions of
those compartments. When water or other more or less volatile liquid

page_text: is employed a certain amount of vapour will be mingled with the air or
gascous fluid, and the tension of such vapour will vary in correspondence
with the pressure and temperature of the gaseous fluid, so that the
alternate generation and condensation of the vapour will conspire with
the alternate expansion and contraction of the gascous fluid to cause the
transference of the liquid, so as to give greater preponderance to the
descending compartments. A liquid such as mercury might be
employed with considerable advantage, as owing to its high specific
gravity, the transference of a comparatively small quantity from one
compartment to another would produce a considerable difference in
weight and give a proportionally great driving power. To prevent in
such a case the generation of mecurial vapour a small quantity of water
or other liquid might be introduced, and this liquid floating on the
mercury would be more or less vaporized the mercury itself remaining in
the liquid condition beneath it. The outer vessel A¹ may be heated by
direct flame applied externally, while the inner vessel A is kept cool
by charging the middle space D with water, and keeping water flowing
into it and overflowing from it through a hollow shaft or by a syphon
pipe. Holes e, e, are provided in the lower part of the space D
communicating with the several compartments b, and passages e¹ com-
municate between these and the several compartments b². These holes
and passages act as safety exits for the liquid in case the pressure of the
gas or vapour should become excessive, thus providing against explosion.
Further, by arranging the holes e so that as the apparatus revolves they
come successively just above the level of the liquid in the middle
space D, the relative quantities of the liquid and of the gascous fluid
within the compartments adjust themselves, there being an inflow or an
outflow of liquid or gas by these holes according as the quantity of
cither is deficient or in excess.
Fig. 8, Sheet II., represents a side view, and Fig. 9 a plan of a like
apparatus somewhat modified in construction; Fig, 10 being a section
on the line a-b, and Fig. 11 a section on the line c-d, Fig. 9. In this
construction there are two separate compartments, the one which is
kept cold by water in the middle space E communicating freely with
water it its outer spaces F and G by passages under diaphragms ƒ and g ;
and the other hot compartment of a U shape placed transversely to the
cold compartment, and having its limbs I and K therefore alternating.
with the limbs F and G of the cold compartment. The limbs I and K

page_text: are heated by flue pipes i and k which convey through them the
products of combustion from a burner L situated within a neck projecting
downwards from the hot compartment. This apparatus being mounted
on an inclined axis M and intended to rotate in the direction of the
arrow (Fig. 9), has the upper parts of its hot compartment connected
with the upper parts of the cold compartment by passages N connecting F
to I, and O connecting G to K, in which passages regenerators may be
provided. The limbs I and K being kept heated and F and G cooled,
the action is as follows:-Supposing F to be at the upper and G at the
lower part of its revolution when I is descending and K ascending, then
owing to the obliquity of the axis, G contains most water and least air,
while F contains most air and least water, consequently most of the
air of G has passed into K. while air has been supplied to F from I;
but the air in K being heated and expanded while that in F is cooled
and contracted, water is transferred from K to I, or the descending
limb I is made to preponderate over the ascending limb K. Again,
supposing I to be at the upper part and K at the lower part of its
revolution while F is ascending and G is descending, then the air of K
and G being mostly in the cold limb G is contracted, while the air of
F and I being mostly in the hot limb I is expanded, and thus there is
more water in the descending limb G than in the ascending limb F.
And in a similar manner at other parts of each revolution the descending
limbs are made to preponderate, and this preponderance furnishes a
motive power.
The cold compartment being in free communication
with the middle space E, while each limb of the hot compartment com-
municates by the regenerators N, O, with the cold limbs there is no
danger of excessive pressure within the apparatus. The diaphragms
fand g extend down to such depth that when the apparatus revolves on
its inclined axis, the lower edge of each diaphragm comes in its turn
to coincide with the level of water in E (indicated by the dotted
linc N¹, Fig. 10), and thus the relative quantities of air and water in the
compartments adjust themselves, flowing out under the diaphragms
when in excess or flowing in when deficient. In this apparatus as in
those forms previously described, regenerators at N, O, would serve to
economize heating and cooling power.
Having thus described the nature of the said Invention and in what

page_text: First. The use of a caloric engine constructed and operating, sub-
stantially as herein described in reference to Figs. 1, 2, 3, and 4, Sheet I.,
in which engine two vessels connected to cranks on a shaft reciprocato
upwards and downwards the one in a heated and the other in a cooled
liquid, so that air or other gas transferred alternately from the one to
the other through a passage which may be provided with a regenerator
is alternately dilated and contracted, thereby producing a preponderance
of pressure in the direction of movement.
Second. The use of a caloric engine constructed and operating sub-
stantially as herein described in reference to Figs. 5, 6, and 7, Sheet II.,
in which engine two vessels containing liquid and gas, the onc vessel
heated and the other cooled are mounted on an inclined axis, and are
divided into compartments communicating by passages which may be
fitted with regenerators in such manner that the gas transferred
alternately during rotation from a hot to a cold and from a cold to a hot
compartment is alternately contracted and dilated, so as to cause a
preponderance of liquid to exist in the compartments which are in the
descending part of their revolution.
Third. The use of the modified form of caloric engine of the kind last
referred to, constructed and operating substantially as herein described
in reference to Figs. 8, 9, 10, and 11, Sheet II., in which engine the hot
and cold vessels have cach two limbs arranged in alternate order on tho
inclined axis.
In witness whereof, I, the said Charles William Siemens, have here.
unto set my hand and scal, this Twenty-fourth day of December,
in the year our Lord One thousand eight hundred and seventy-
Assas
C. WILLIAM SIEMENS. (L.S.)