AN IMPROVED CALORIC-ENGINE
Year: 1880

page_text: LETTERS PATENT to Patrick O'Halloran, of No. 28, Southampton Buildings,
Chancery Lane, in the County of Middlesex, Patent Agent, for an Invention
of "AN IMPROVED CALORIC-ENGINE." A communication from abroad by
Jabez Jenkins, of Philadelphia, Pennsylvania, United States of America.
PROVISIONAL, SPECIFICATION left by the said Patrick O'Halloran at the
Office of the Commissioners of Patents on the 3rd May 1880.
PATRICK O'HALLORAN, of No. 28, Southampton Buildings, Chancery Lane, in
the County of Middlesex, Patent Agent. "AN IMPROVED CALORIC-ENGINE."
A communication from abroad by Jabez Jenkins, of Philadelphia, Pennsylvania,
United States of America..
A dish-shaped vessel is attached at two points of its edge to a frame, and a broad
piston composed of two circular discs of metal about the size of the bottom of the
aforesaid vessel is attached to said vessel in manner heroinafter described. Between
the discs is a flexible diaphragm formed of any suitable material, as vulcanized
sheet gum-elastic with a layer of canvas on each side of it, or at least on the outside,
The gum renders the diaphragm air-tight, whilst the canvas prevents it from
yielding to pressure. This diaphragm is secured to the rim of the dish so as to
forin a tight enclosure, and its flexibility allows the piston to move slowly up and
down, its movement being about one third the diameter of the piston. The piston
is connected through a cross-head with a crank, and the cross-head has guides
which slide in holes through attachments. A rectangular metallic vessel having
tongues or blades extending from its bottom nearly to its top and cast in one
piece is attached to said frame. This last described vessel is the heater, and the
tongues having their lower edges virtually in the fire, and being very close together,
furnish a very large heating surface. To insure the immediate expansion of air
thrown into this vessel, the heater is connected with the dish-shaped vessel or
piston-box by a pipe.' Another piston-box similar to that herein before described,
and having its bottom upwards and its piston downwards, is attached to the frame.
This lust mentioned piston has a cross-head, its ends working in slots in the frame,
and it is also connected with the beater by a pipe which has a valve at the bottom.
This pipes opens into a gallery at one end of the heater, and the spaces between

page_text: the aforesaid tongues connect with this gallery, and extend through and open into
a similar gallery, at the other end of which another pipe connects with the dish-
shaped vessel. Rods extend from the hereinbefore last described cross-head to
cranks on the end of the main shaft. These cranks work in slots to regulate the
time and distance of the movement of the second or lower piston. The upper or
first described piston being propelled upward by air expanded in the heater, when
the crank reaches to nearly its highest point a pin in the guide lifts a lever hinged
on the outside frame, and opens a valve in the bottom of the piston-box or dish,
thereby removing the pressure and allowing the upper piston to descend. Soon
after the main crank passes the centre, and the pressure is off, the cranks in the
end of the shaft suddenly raise the lower piston, which blows out the heated air
from the heater through the same valve and replaces it with cold air. The upper
piston then descending presses and closes the valve in the dish-shaped vessel,
whereby the air is confined between said valve and the herein before described
valve at the bottom of the pipe. The great heated surface within the heater
immediately expands it, and thus produces another stroke of the piston, and so on.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Patrick O'Halloran in the Great Seal Patent Office on the 3rd
November 1880.
PATRICK O'HALLORAN, of No. 28, Southampton Buildings, Chancery Lane, in
the County of Middlesex, Patent Agent. "AN IMPROVED CALORIC ENGINE,"
A communication from abroad by Jabez Jenkins, of Philadelphia, Pennsylvania,
United States of America.
The improved engine is chiefly designed as a motor for sewing-machines and the
like, in which the expansive power of heated air is employed as the motive
agent. It embraces a construction and combination of elements making a new
organized caloric engine, in which a suitable air-beater is combined with a flexible-
diaphragm piston-motor having direct connection with the crank power-transmitting
shaft and a communication with said heater, and a flexible-diaphragm air-pump
having direct connection with the flexible-diaphragm-piston-motor and a valved
communication with said heater, and in which the expansive action of the flexible-
diaphragm-piston-motor controls a valve within said motor for releasing it of
pressure. The collapsing action of said diaphragm-piston-motor suddenly controls
the operation of the pump to blow out the heated air from the heater, and replace
it with cold air, which being then confined within the chamber of the heater is
immediately expanded to drive out the flexible piston-motor, and by direct con-
nection of its piston-rod impel the power-transmitting shaft. The piston is formed
of metal disks and a flexible or elastic diaphragm of any suitable air-tight material,
and which is protected and supported from undue yielding and strain by one or
more independent layers or covers of canvas or other similar material. The
connection of the pump and motor must be such as to render the pumping action
sudden, and to fill the heater with cold air while the valvo of the piston-motor
chamber is open, and thus the pump does not operate against pressure, and little
power is consumed in its air-forcing movement. Referring to the accompanying
Drawings, Figure 1. represents a vertical section of a caloric engine embracing said
Invention, the flexible-diaphragm-piston-motor being shown as extended, and the
relief-valve open; Figure 2, a similar section, the flexible-diaphragm-piston-motor
being shown as collapsed, its valved chamber closed, and the air-pump having
forced cold air into the heater; Figure 3, a vertical section taken at right angles
to Figure 1; Figure 4, a horizontal section of the air-heater; and Figure 5, a
vertical section of the flexible-diaphragm-piston-motor. In the several Figures
the same letters designate the same parts. It is a primary feature of my Invention
that both the motor and the air-pump are formed of flexible-diaphragm-pistons,
each having a piston-rod, and each having connection through such piston-rods.
A suitable frame supports the operating parts, the arrangement of which is
preferably such as shown, and in which the motor is suitably supported near the
top, the air-pump near the bottom, and the air-heater in intermediate position
upon such frame. The motor-proper consists of a valved chamber a, formed within
and by a suitable armed casting b, and a flexible-diaphragm c forming the upper
side of said chamber, and secured by a clamping-ring d, and provided with metal
disks e forming a broad piston-head from which a piston-rod f1 extends upward
centrally. The diaphragm is of vulcanized rubber, or equivalent material, to bear
a heat of say 300° Fahrenheit, and is air-tight. It is reinforced by a layer or
layers of canvas or other similar covering to protect and support it from undue
strain and yielding to pressure. Such supplemental covering may be on both sides
of the elastic diaphragm, but it is preferably and necessarily used only on the
outer side; but the independent layers of canvas and rubber of the flexible piston
aro an important matter in rendering it durable and equal for the strain, and upon

page_text: this or equivalent construction of the diaphragm depends the successful operation
of the engine. This flexible piston-motor connects directly with the power-
transmitting crank-shaft ƒ by a connecting rod f, while a cross-head f" and guide-
rods f moving therewith give proper support to the piston-rod. The air-pump a
forms a similar flexible piston with a valve, but in which the flexible diaphragm c
forms the lower side thereof, is secured by a ring d³, and provided with metal disks e²,
from which the piston-rod e³ extends downwards centrally and axially, coincident
with the piston-rod of the motor proper. The air-pump, however, may be of any
suitable form and construction, so long as it has a yielding side. The piston-rod e³
connects by a cross-head f moving in frame-guides f³ to give the proper support to
the piston-rod, and as means by which to connect it with the power-transmitting
shaft. The rods i, i, by which this connection is made are attached to each end of
the cross-head f4, and to cranks j, j, on each end of the power-transmitting crank-
shaft. This crank-connection however is by slots ¹, j¹, in connection with which
the cranks j, j, must bear certain relation to the motor-crank of the driven shaft
for a purpose to be presently stated. The heater is located intermediately with the
motor and with the pump, and consists of a cast-metal closed box k, provided with
separate ribs ¹ rising from its bottom to near its top, and leaving a space k²
at its opposite ends, as shown in Figures 3 & 4. The ribs are near together,
are readily heated from the bottom plate with which they are cast, and form a
large heating-surface to insure the immediate expansion of the air as soon as
it is confined. The chamber a of the flexible piston-motor has a communication
with the space at one end of the heater by the pipe l, and the chamber
a¹ of the air-pump connects with the space at the opposite end of the heater by
the pipe, which, however, is provided with a valve arranged to open outward
from the pump-chamber, as shown in Figure 3. The spaces between the ribs k' opon
into the space k², and for the purpose of preventing the air-currents from
blowing through a few of the central spaces of the ribs I provide the plate m,
depending from the top of the heater in close proximity to the ends of the ribs, and
between them and the end of the air-conducting valved pipe ", which extends
within the space k and just above the lower edge of the plate m, which thus serves
as an apron to equalize the passage of the cold air into and through the
spaces of the heater. The small space between the top of the heater and
the top of the ribs is to prevent the heat being conducted to the top plate, and thus
wasted. This isolation of the top of the heater gives an important advantage
in utilizing the heat from the multiple walls of the heater. The unyielding side of
the flexible piston-motor chamber is provided with a valve n opening inward, and
it is automatically opened by means of an arm o pivoted to the frame, and operated
by a tappet or catch o' on one of the guide-rods f³ of said flexible piston-motor,
when the latter has nearly reached its limit of distention. The air-pump is
provided with a valve p, also opening inward, and carried by the yielding side of
the pump-chamber, and, like the valve , is opened and closed by the movement
of the pump-diaphragm. It is important to the successful working of the motor
that the pump shall have a quick pumping action, and at a particular part
of the stroke of the flexible piston-motor, and for this purpose the cranks j,j,
of the power-transmitting shaft must be of such length and have such relation
to the piston-motor connecting crank j³ and to the upper ends of the slots j¹, j¹, of
the connecting-rods i, i, as to cause said cranks ; to lift the flexible diaphragm
of the pump-chamber when the cranks j, j, nearly reach their highest point,
thereby pumping fresh cold air into the heater, and forcing the hot air out as the
flexible piston-motor is closing within its chamber. It is important in this
connection that the pump-chamber and the heater shall be about three times
the area of the chamber of the flexible-diaphragm-piston-motor, so as to insure a
supply of cold air that will give the requisite expansive force upon the broad piston.
As the motor-diaphragm descends the valve in the chamber of the said motor,
having been held open by friction, closes by reason of being pressed upon by

page_text: the descending piston. The rods which connect with the pump-diaphragm also
descend, and carrying with them said diaphragm allow the valve 12 in the
heater connecting-pipe to close while the valve p in said diaphragm opens,
thereby filling the large pump-chamber with cold air to be pumped into the heater
at the proper time to operate the piston by its expansive force, and during such
expansion it is confined within the heater and the motor-chambers by the closing
of the valve placed in the pipe which supplies the heater with the air from
the pump.
In this way the power-transmitting shaft is revolved by the
action of the motor-diaphragm-piston. The heat is applied to the bottom of the
heater and in an engine for operating a sewing-machine; it may be furnished by a
suitable oil or gas stove placed on the top of the pump and within a suitable box
depending from the heater. For a larger engine a coal fire may be suitably
arranged. By this construction a sufficient power can be obtained to operate
a sewing-machine or a churn at an expansive temperature of the air of from 250°
to 300° F., and which will not injure the rubber diaphragm. A vulcanized
diaphragm is not essential for the pump, but it may be of oil-cloth or other suitable
airtight material re-enforced by separate layers of canvas. The chamber of
the piston-motor may be either cast or formed of pressed sheet metal. Tho
movement of the piston-motor-diaphragm is equal to about one-third its diameter,
and it is free from the friction incident to a cylinder and piston-head, and is
casily renewed when necessary. As a small engine it will be found efficient
and durable and comparatively of little cost. An important advantage in its
construction is the pumping of the air into the heater comparatively free from
pressure, and therefore there is little power expended to work the pump during
the descending movement of the piston-motor; and by making the cranks j, j
and the slots within which they work of suitable length, the raising of the
pump-diaphragm may be effected in a quarter revolution of the driven shaft,
and this action is timed by the proper placing of these cranks relative
to the piston-rod crank of the motor. The power is transmitted from a
pulley A on the driven shaft, which is of sufficient weight to act also as a
fly-wheel. It is important to notice that the valve n is so hinged as to
be held open by friction, and that the wholo discharge of the heated air, of
which the cold air takes its place, is through this valve as follows, viz.:-Tho
crank-shaft revolving to the right, the short crank having passed the center, and
the valve having been open since said crank was about the same distanco on the
outer side of the center, thus gives time for the pressure in the chamber to pass off.
The valve still remains open, while the slotted cranks now operate the pump,
blowing out the hot air through this open valve. I am aware that prior to this
Invention single and double diaphragms of rubber have been used in motors and
gas-regulators; that such diaphragm has been made with a layer or facing of tin-
foil or other flexible metallic coating to protect the rubber, and to render it
impervious to gas, and that a molded diaphragm composed of two or more strata
of vulcanized rubber has been used with interposed stratum of textile fabric; but
my improved piston-diaphragm differs from these things in being composed
of a rubber diaphragm to form an air-tight chamber, and one or more independent
diaphragms of canvas upon the outer surface of the rubber diaphragm, the
function of which is to receive and bear all the strain upon the rubber diaphragm,
and prevent it from being unduly distended, the action of which would in
a short time disintegrate the rubber. In fact, the canvas is the supporting and
operating connection for the power-transmitting rod, the rubber being used
only for its air-tight qualities. Its use as a propelling material under constant
movement and strain renders it inadequate for the purpose of a piston-motor; it
cannot withstand propelling force. Moreover, it has been found in practice that
the action of the canvas support for the propelling rod must be to a certain extent
independent of the air-tight diaphragm, in order to restrain the action of the latter
within its normal limits and to give a free support to the rubber diaphragm, and in

page_text: this function it is of prime importance to the successful use of a rubber diaphragm
as a propelling piston.
Having thus fully described the said Invention as communicated to me by my
client, in a caloric engine I claim,-
First. The combination of a flexible-diaphragın piston-motor, a separate flexible-
diaphragm air-pump, and a closed air-heater having communication with tho
chamber of the said flexible-diaphragm piston-motor, and also with the chamber of
aaid air-pump, the flexible diaphragm of said air-pump being connected with and
controlled by the flexible diaphragm of said piston-motor for controlling the
admission of air to said heater.
Second. The combination of a flexible diaphragm piston-motor, a flexible-
diaphragm air-pump, and a closed air-heater with a valve in the chamber of said
piston-motor, and a pivoted arm operated by the diaphragm of said piston-motor to
open said valve by pressure for relieving said piston-motor of the expansive force
of the air in the heater.
Third. The combination of a flexible-diaphragm pistou-motor, a flexible-
diaphragm air-pump, and a closed air-heater, constructed for conjoint operation,
substantially as herein set forth, the said air-pump having a free operative con-
nection with the driven crank-shaft of the said piston-motor for effecting a quick
movement of the pump, for the purpose stated.
Fourth. The closed air-heater consisting of the case or box having an
uninterrupted closed bottom, and solid separated ribs rising therefrom, but not
touching the top nor the ends of said heater, for increasing the air-heating surface
within said closed case or box, in combination with the cold-air-pump-supplying-
pipe and the flexible-diaphragm piston-inotor, substantially as herein set forth.
Fifth. The closed air-heater provided with interior separated ribs rising from
the bottom, but not touching the top nor extending to the opposite ends of said
heater, leaving uninterrupted end spaces, in one of which an apron m depends in
position to equalize the circulation and passage of the cold-air from the pump-
supplying pipe into and through said heater.
Sixth. The closed-air heater communicating by a pipe from one end and from
the top thereof with the chamber of the piston-motor, and communicating with the
chamber of the air-pump by a pipe extending into and from the bottom of the
opposite end of said heater, for causing the air to be impelled into and through said
heater from one end to the other in its course to said piston-motor chamber.
Seventh. The combination of a flexible-diaphragm piston-motor provided with a
valve controlled by and for controlling the operation of said motor, a flexible-
diaphragm air-pump controlled by said piston-motor, and a closed air-heater, with
a valve arranged in a pipe which connects said pump and heater, and opened and
closed by the action of the pump, for the purpose stated.
Eighth. The flexible-diaphragm piston-motor and the flexible-diaphragm piston-
pump, cach connected by a centrally coincident piston-rod and with the power-
transmitting crank-shaft, and having a connected heater arranged between them,
the said piston-rods extending in opposite directions, and suitably supported by
guides.
Ninth. The combination of a flexible-diaphragm piston-motor having a valve
controlled substantially as herein set forth, a flexible diaphragm piston-pump, and
a closed air-heater communicating with said piston-motor and air-pump, with the
slotted rods connecting said pump with the power-transmitting shaft and tho
said piston-motor to effect the objects stated.
Tenth. The flexible-diaphragm piston-motor provided with a valve opening
within its chamber by outward pressure in combination with the pivoted arm o,
and the actuating tappet o¹, carried and controlled by the cross-head guides of said
piston-motor for controlling the operation of said valve to control the operation of
said piston-motor.
Eleventh. The flexible diaphragm of a piston-motor, consisting of an air-tight

page_text: rubber diaphragm c or equivalent material, and an outer independent support of
canvas c³, in combination with the power-transmitting rod c¹, the middle clamping-
plates e, and the casing b, are substantially as and for the purpose specified and
illustrated in detail in Figure 5.
In witness whereof, I, the said Patrick O'Halloran, have hereunto set my hand
and seal, this Second day of November, in the year of our Lord One thousand
eight hundred and eighty.
Signed and sealed
in presence of
G. M. O'HALLORAN,
28, Southampton Buildings,
E.C.
PATRICK O'HALLORAN. (L.S.)