IMPROVE- MENTS IN CALORIC ENGINES
Year: 1879

page_text: LETTERS PATENT to Charles Denton Abel, of No. 28, Southampton Buildings,
Chancery Lane, in the County of Middlesex, for the Invention of "IMPROVE-
MENTS IN CALORIC ENGINES." A communication from abroad by Julius
Hock, of Vienna, in the Empire of Austria.
PROVISIONAL SPECIFICATION left by the said Charles Denton Abel at the
Office of the Commissioners of Patents on the 17th October 1879.
CHARLES DENTON ABEL, of No. 28, Southampton Buildings, Chancery Lane, in
the County of Middlesex. "IMPROVEMENTS IN CALORIC ENGINES." [A communi-
cation from abroad by Julius Hock, of Vienna, in the Empire of Austria.]
These improvements relate to that description of caloric engines in which
atmospheric air is forced under pressure into a closed furnace, where it partly enters
into combustion with the fuel, and partly, after becoming highly heated, passes
together with the gaseous products of combustion into the working cylinder to
propel the piston. Such a construction of engine was described in the Specification
to Letters Patent granted to me as a communication from the said J. Hock, on the
9th September 1876, No. 3550.
The present improvements consist, firstly, in regulating the power of the engine
by causing part of the air under pressure to pass directly from the air pump through
the admission valve into the working cylinder without passing into the furnace
when the engine is running beyond the normal speed; secondly, in effecting such
division of the air supply by means of a governor of any known construction, in
such manner that according to the speed of the engine it either causes the whole of
the air supply to pass into the furnace, or only a portion thereof, the remainder
being caused to pass directly to the cylinder; or it closes both the above communi-
cations, so as to cause the increased resistance thus offered to the action of the air
pump by the increased compression of the air to act as a break for retarding the
motion of the engine.
For these purposes the pipe leading from the air pump to the furnace has a
branch leading direct to the chamber of the admission valve of the engine, and in
Prins 31

page_text: this branch, as also in the part of the main pipe beyond such branch, is a throttle
valve, the two, valves being so connected by an arm on the spindle of the one
bearing against an arm on the other that the movement of the one valve in one
direction will also cause the movement of the other valve, while they are otherwise
independent of each other. The first named valve, which is that situated in the
branch pipe, being connected to the governor, lever is held by the governor in the
closed position when the engine is running at its slowest speed, while it holds the
other valve full open, so that the whole of the air supply now passes to the furnace.
On the speed increasing the governor opens the first valve, more or less, which in
its turn allows the second valve to be closed, more or less, by a weighted arm
connected thereto, and in this position a portion of the cold air supply passes
directly through the admission valve into the cylinder, thereby also cooling the
valve and the working parts connected therewith. On a still greater increase of
speed occurring the governor fully opens the branch valve, while at the same time
the other valve is entirely closed by its weighted arm, so that the air supply is then
entirely cut off from the furnace, the whole thereof passing through the admission
valve into the cylinder. On the engine running still faster the governor causes the
branch valve to move over into the opposite position to that first described, so
as again to close the branch pipe, and both communications being now closed, the
pump in compressing the air in the supply pipe to an increasing extent serves as a
break to retard the speed of the engine. This action does not cause any appreciable
loss of effect, as the compressed air is afterwards utilised when the throttle valves
again open the communications. In order to balance the pressure of the heated
compressed air on the back of the admission valve, so as to allow this to be opened
easily by its eccentric, the valve stem is extended upwards, and is connected to a
piston of about the same area working air tight in a small cylinder, the lower part
of which communicates by a small pipe with the passage above the valve leading to
the working cylinder, while the upper part of the small cylinder is connected by
another small pipe to the air supply pipe. Thus the piston being pressed down-
wards by about the same air pressure as that acting on the underside of the valve,
this is practically balanced. The weight of the small piston may be balanced by a
helical spring supporting it inside the cylinder.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Charles Denton Abel in the Great Seal Patent Office on the 12th
April 1880.
CHARLES DENTON ABEL, of No. 28, Southampton Buildings, Chancery Lane, in
the County of Middlesex. "IMPROVEMENTS IN CALORIC ENGINES." A communi-
cation from abroad by Julius Hock, of Vienna, in the Empire of Austria.
These improvements relate to that description of caloric engines in which
atmospheric air is forced under pressure into a closed furnace, where it partly
enters into combustion with the fuel, and partly, after becoming highly heated,
passes together with the gaseous products of combustion into the working cylinder
to propel the piston. Such a construction of engine was described in the Specifi-
cation to Letters Patent granted to me as a communication from the said J. Hock,
on the 9th September 1876, No. 3550.
The present improvements consist, firstly, in regulating the power of the engine
by causing part of the air under pressure to pass directly from the air pump
through the admission valve into the working cylinder without passing into the
furnace when the engine is running beyond the normal speed; secondly, in effecting
such division of the air supply by means of a governor of any known construction,
in such manner that according to the speed of the engine it either causes the whole
of the air supply to pass into the furnace, or only a portion thereof, the remainder
being caused to pass directly to the cylinder; or it closes both the above communi-
cations, so as to cause the increased resistance thus offered to the action of the air
pump by the increased compression of the air to act as a break for retarding the
motion of the engine.
For these purposes the pipe leading from the air pump to the furnace has a
branch leading direct to the chamber of the admission valve of the engine, and in
this branch, as also in the part of the main pipe beyond such branch, is a throttle
valve, the two valves being so connected by an arm on the spindle of the one
bearing against an arm on the other that the movement of the one valve in one
direction will also cause the movement of the other valve, while they are otherwise
independent of each other. The first named valve, which is that situated in the
branch pipe, being connected to the governor lever is held by the governor in the
closed position when the engine is running at its slowest speed, while it holds
the other valve full open, so that the whole of the air supply now passes to the
furnace. On the speed increasing the governor opens the first valve, more or less,
which in its turn allows the second valve to be closed, more or less, by a weighted
arm connected thereto, and in this position a portion of the cold air supply passes
directly through the admission valve into the cylinder, thereby also cooling the
valve and the working parts connected therewith. On a still greater increase of
speed occurring the governor fully opens the branch valve, while at the same time
the other valve is entirely closed by its weighted arm, so that the air supply is then
entirely cut off from the furnace, the whole thereof passing through the admission
valve into the cylinder. On the engine running still faster the governor causes
the branch valve to move over into the opposite position to that first described, so
as again to close the branch pipe, and both communications being now closed, the
pump in compressing the air in the supply pipe to an increasing extent serves as a
break to retard the speed of the engine. This action does not cause any appreciable
loss of effect, as the compressed air is afterwards utilised when the throttle valves
gain open the communications. In order to balance the pressure of the heated
compressed air on the back of the admission valve, so as to allow this to be opened
easily by its eccentric, the valve stem is extended upwards, and is connected to a
piston of about the same area working airtight in a small cylinder, the lower part
of which communicates by a small pipe with the passage above tlie valve leading

page_text: another small pipe to the air supply pipe. Thus the piston being pressed down-
wards by about the same air pressure as that acting on the underside of the valve,
this is practically balanced. The weight of the small piston may be balanced by a
helical spring supporting it inside the cylinder.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 of the Drawings shews an elevation of the engine with vertical section
through the air pipes; Fig. 2 shews a side view of the engine with the valve boxes
in section; Fig. 3 shews a vertical section through the engine cylinder and furnace ;
Figs. 4 and 5 shew to an enlarged scale an elevation and plan of the throttle valves
in the air pipes; Fig. 6 shews a plan of the engine.
The general construction and mode of operating of this engine is similar to that
described in the Specification to the beforementioned Patent, and need not there-
fore be again described. An ordinary centrifugal governor driven by the gearing
k, l, from the fly wheel shaft m acts by means of the double ended lever a, rod b,
and lever d, on the two throttle valves T and U. These valves, the arrangement
and relative position of which will be seen from Figs. 4 and 5, are partly dependent
upon and partly independent of each other in their motion. In the position shewn
at Fig. 4 the valve U is quite closed, the valve T being quite open. If now the
rod b actuated by the governor descends U remains closed, the weighted arm i
tending to keep it so, while T also gradually closes, the closing being effected
in the highest position of the governor. If on the other hand the rod b rises from
the position shewn at Fig. 4, the valve U will be gradually opened by the finger on
the spindle of the valve T, and will be quite open when the valve T, which at the
same time moves into the closing position, is entirely closed, this being the lowest
position of the governor. At the slowest speed of the engine therefore the throttle
valve T will be entirely closed, and U will be quite open. In consequence thereof
the total quantity of air delivered by the air pump N, and passing through the
valve to the air pipe R, will find its way through the valve Û into the passage U¹,
lined with fireclay, into the heater H. From this the air passes through openings
near the firedoor E into the furnace A, and from this it passes lastly through the
valve box Z into the working cylinder K.
If the engine runs faster, and the governor begins to rise in consequence, the
valve T will by the descent of the rod b be more and more opened, and the valve U
be correspondingly closed by its weight i. The whole of the air now no longer passes
through the valve U to the furnace, a portion thereof passing through the branch
pipe S and valve T to the valve box Z, and thence to the cylinder without passing
through the furnace, that is to say, in a cold condition. This current of cold air
passing to the valve box Z has at the same time the effect of cooling the valve
between the furnace and the working cylinder, as also all parts of the valve box
with which it comes in contact.
On suddenly taking the work off the engine when highly heated and working with
its full power, the above described mode of regulation will not be found sufficient,
this being only intended for ordinary variations in power when working.
When after completely closing the valve U and opening the valve T, when no
air will pass to the furnace, the governor still continues to rise, the descent of the
rod b will cause the valve T to close again, more and more, on the opposite side
to that in which it first closed, thereby more and more obstructing the passage of
the air, and eventually entirely cutting it off. The engine will by this means be
retarded or have a brake action automatically applied to it by reason of the
accumulation of pressure in the pipe R, such accumulation being afterwards usefully
expended again when the work of the engine increases. Figs. 7 to 9 shew the
before described arrangement for relieving the admission valve of pressure in order
that it may be more easily worked; Fig. 7 shews a back view of the engine;
Fig. 8, a side view with section through the valve boxes; and Fig. 9 is a sectional

page_text: plan. A is the admission valve situated in the valve box Z between the furnace
and the working cylinder. This valve is connected by a rod B to a piston C
working air tight in the cylinder D, a helical spring in the lower end of which
presses the piston continuously upward. The valve box Z communicates by a
branch pipe f with the working cylinder, and by a second branch pipe f* below
the valve with the furnace; R is the air pipe for conducting the compressed air
from the force pump to the furnace; g is a small pipe connecting the lower part
of the cylinder D with the branch f¹; e, e, is a similar pipe connecting the upper
part of cylinder D with the air pipe R.
When the valve A is closed, it is pressed down on its seat by the air pressure
existing in the furnace. Against this upward pressure acts the downward pressure
exerted on the upper side of piston C. This piston having an area equal to or
slightly less than that of the admission valve, and the pressure above the piston
being equal to that existing in the pipe R, and therefore also. in the furnace,
in consequence of the connection by means of the pipe g, it follows that the
pressure upon the piston C will entirely, or almost entirely, balance the pressure on
the valve A.
Having thus described the nature of the said Invention and in what manner the
same is to be performed, as communicated to me by my foreign correspondent, I
claim in respect of caloric engines of the kind herein referred to,-
First. Regulating the power of the engine by means of a governor arranged and
operating in combination with two throttle valves on the air supply, in such
manner that either the whole of the air supply is caused to pass into the furnace,
or that a portion thereof is caused to pass directly into the cylinder without being
heated, or that the whole of the air supply to the working cylinder is cut off and is
caused to accumulate in the air supply pipe, so as by the resistance offered thereby
to retard the speed of the engine, substantially as herein described.
Second. The combination of a governor with two throttle valves U and T,
situated respectively in the air supply pipe R leading to the furnace and in a
branch pipe S leading directly to the admission valve A of the working cylinder,
whereby a portion of the cold air supply can be caused to pass directly into the
cylinder through the admission valve, in order both to regulate the power of the
engine and to cool the valve box, substantially as herein described.
"
Third. The herein described arrangement of apparatus for relieving the admission
valve to the working cylinder from pressure.
In witness whereof, I, the said Charles Denton Abel, have hereunto set my
hand and seal, this Twelfth day of April, in the year of our Lord One
thousand eight hundred and eighty.
CHA³. D. ABEL. (L.S.)