IMPROVEMENTS IN AND RELATING TO HOT-AIR ENGINES to be as follows
Year: 1884

page_text: I WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake, and Co, Patent Agents,
Southampton Buildings, in the County of Middlesex do hereby declare the nature
of my invention for "IMPROVEMENTS IN AND RELATING TO HOT-AIR ENGINES
to be as follows:-
"
This invention relates to the utilization of hot air as a motor, and to apparatus
therefor.
Heat is a source of power, and the most advantageous means of turning it to
account is to utilize it for augmenting the volume of gases. of combustion, by
raising them to the maximum temperature of the combustion; when the gases are
only utilized at a temperature of about 300° Centigrade, these gases merely double
their volume, consequently the cold air feed-pump absorbs half the power produced
and the losses of heat, friction & waste a portion of the other half so that the
best air-engines are much less effective than good condensing steam engines with
expansion.
.
The air-engine which forms. the subject of this invention and which is based
upon the direct utilization of the gases produced by the combustion, raised to the
maximum temperature, has an effectiveness which is far above that of air-engines
and of ordinary steam-engines heretofore constructed.
The gases of combustion are employed at their highest degree of temperature,
the motor being specially constructed so as to enable the same to resist, this high
temperature, and provided with recuperators or regenerators and refrigerators.
designed to produce changes in the volume of the gaseous substance contained in
the apparatus, according as it is displaced from the hot portions or from the cold
portions of this apparatus.
It is obvious that owing to the very considerable differences of temperature at
the two ends of the motor, the power obtained through these variations of volume
is very considerable.
According to the present invention the coal is first converted into oxide of
carbon which is then burnt. Every kind of coal may thus be used with economy

page_text: '
and a perfectly regular combustion, the products of which do not contain any free
oxygen, can be obtained, thereby allowing the employment of metals for the
recuperation of the heat between 1000 and 300 degrees C. Refractory materials
only should be used above 1000 degrees. A stream of cold water is sufficient to
effect the complete cooling of the gases.
In the improved apparatus the pressure of the gases being, for instance two
atmospheres, their evacuation after cooling provides the motive power requisite
for the compression to this pressure of the cold air, and at the same time enables
the cooling of certain portions of the motor to be effected.
The description, of the motor will enable the mode of operation to be understood.
In the accompanying drawing
Figure I is a vertical section of the improved motor.
Figure 2 is a plan showing the general arrangement of the motor and its
connections as arranged in practice.
The apparatus comprises essentially the following parts; The cylinder A having
a piston B; a recuperator F, for the high temperatures, filled with refractory
materials; a recuperator H, for mean temperatures, filled with metallic plates
and fragments of refractory materials and a refrigerator J, for temperatures below
300 degrees, operating by means of cold water. It also comprises a pump L for
the evacuation of the cold gases; the oxide of carbon generators O and O¹; and the
air-pumps and Z', Figure 2, which feed these generators when operated with
pressure.
The cylinders of the motor being single acting, a complete motor naturally
comprises two cylinders and connections.
As shown in Figure 2, the four cylinders A L, A¹ L¹ are arranged in one single
row so that the piston-rods C and M act directly through the medium of con-
necting-rods, D N upon the general driving-shaft XX, by which means a continuous
and uniform motion of the motor is obtained..
The driving pistons P and P¹ actuated by the cooled gases on their exit from the
apparatus, have for their object to effect the displacement of the large pistons B
and B¹. The latter have refractory coverings enabling them to bear the high
temperatures to which they are subjected. These two pistons P P¹ receive con-
stantly and in turn the cooled gaseous products, determined quantities of which
they allow to escape through clack-valves arranged in their bodies, or in any other
suitable manner, and they force alternately the remaining portions into the recu-
perators where they are again heated in order to return above the pistons B B
of the apparatus, being mixed with the beated gases arriving from the generators
through the orifice V.
This enormous augmentation of volume in this latter case produces the great
power of the engine. The air-pumps merely serve to convey into the oxide of
carbon generators the air necessary for restoring the lost heat.
The cylinder A has a covering of fire-bricks, perfectly cemented; of about
20 centimeters thickness at all parts exposed to high temperature.
The piston B has a rod and is steadied by stays a a. The said piston-rod passes
through a guide e, c, d for maintaining it invariably in a vertical line parallel with
the sides of the piston B.
The piston B has also a cast iron prolongation i without a refractory lining
which is strengthened by ribs which enable the air to circulate freely and to cool
the sides.
m indicates a circular groove in the piston, in which is placed a packing ring n
of bronze or other suitable material which slides upon the prolonged cast-iron sides.
of the cylinder A. This vertical circular wall upon which the ring n slides is
lubricated, and is cooled by a continuous current of cold air circulating through.
the jacket o, o, This cold air is supplied by the air-pump Z and is heated in the
jacket before passing to the oxide of carbon generators.
When necessary, the cooling of this part of the cylinder A is effected by means
of a current of cold water.
I

page_text: The pipe I conducts the gases, cooled down to less than 300 degrees, into the
cold water refrigerator J, and the tubes K conduct the cooled gases into the small
cylinder L, the piston-rod M of which has a guide . N is the connecting-rod of
the small cylinder.
V is the inlet for the gases of the generator O, and T is the inlet for the atmo-
spheric air which serves for the combustion of these gases."
So far it has been supposed that the motor operates with an internal pressure of
two atmospheres, the pump Z conveying the air against this pressure into the oxide
of carbon generators 0; but it is obvious that it can also be worked at the pres-
sure of the atmosphere, by closing the lower part of the small cylinder L (the rod M
of the piston P traversing in that case a stuffing-box) and creating a vacuum below
the piston P by means of the air-pump Z which would otherwise be of no use; the
portion of the gases which it is desired to evacuate passing through clack-valves
arranged for this purpose in the piston P.
It will be understood that the system can also be arranged in such a manner
that the vacuum can be created above the piston P, and the atmospheric pressuro
existing on the lower side of the piston be utilized, in order to obtain the motivé
power of the apparatus.
This latter method is perhaps preferable, provided there is no pressure in the gas
producing apparatus, because the necessity of producing oxide of carbon under a
pressure of two atmospheres is obviated.

page_text: COMPLETE SPECIFICATION.
Improvements in and relating to Hot-air Engines.
I, WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake, and Co, Patent
Agents, Southampton Buildings, in the County of Middlesex do hereby declare
the nature of my invention for "IMPROVEMENTS IN AND RELATING TO HOT-AIR
ENGINES" and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
°
This invention relates to the utilization of hot air as motive power and to
apparatus therefor.
.
Heat is the source of power, and the most advantageous means of turning. it to
account is to utilize it for augmenting the volume of gases of combustion, by
raising them to the maximum temperature of the combustion. When the gases
are only employed at a temperature of about 300° Centigrade, their volume, is only
doubled, consequently the cold air feed pump absorbs half the power produced and
the losses of heat friction etc waste a portion of the other balf so that the best air-
engines are much less effective than good condensing steam engines working with
expansion.
The air-engine which forms the subject of this invention, and the construction of
which is based upon the direct employment of the gases produced by the combus-
tion, at their maximum temperature, has an effectiveness which is far above that
of air-engines and of ordinary steam-engines as heretofore constructed.
The gases of combustion are employed at their highest degree of temperature,
the apparatus or motor being specially constructed so as to enable the same to
resist this high temperature, and provided with recuperators or regenerators and
refrigerators designed to produce changes in the volume of the gaseous substance
contained in the apparatus, according as it is displaced from the hot portions or
from the cold portions of the said apparatus..
It is obvious that owing to the very considerable differences of temperature at
the two ends of the motor, the power obtained through these variations of volume
is very considerable. The motor is also superior in point of effectiveness to motors
as heretofore constructed, by reason of the facility with which a very large portion
of the waste heat can be recuperated.
A considerable saving in the consumption of fuel can thus be effected with the
improved motor; for instance in an ordinary engine of 100 horse-power 3120
kilograms of coal are used every twenty four (24) hours whilst a motor constructed
according to this invention consumes only 400 kilograms of coal for the same
power.
With marine boilers this saving of fuel is very advantageous as in consequence
of less coal being required more space in the vessel is available for ordinary cargo.
According to the present invention the coal is first converted into oxide of carbon
which is then burnt. Any kind of coal may be used with economy, and a perfectly
regular combustion, the products of which do not contain any free oxygen can be
obtained, thereby permitting the employment of metals for the recuperation of the

page_text: -heat between 1000 and 300 degrees. Refractory materials only should be used
with temperatures above 1000 degrees. A stream of cold water is sufficient to
effect the complete cooling of the gases.
In the improved apparatus the pressure of the gases being, for instance, two
atmospheres, their evacuation after cooling provides the motive power requisite for
the compression to this pressure of the cold air, and at the same time enables the
cooling of certain portions of the motor to be effected.
The description of the motor will enable the mode of operation to be understood.
In the accompanying drawing.
Figure 1 is a vertical section of the improved motor and
Figure 2 is a plan showing the general arrangement of the motor and its
connections as arranged in practice.
The apparatus consists essentially of the following parts: viz The cylinder A
having a piston B; the recuperator F, for high temperatures, filled with refractory
materials; the recuperator H, for mean temperatures, filled with metallic plates
and fragments of refractory materials, the refrigerator J, for temperatures below
300 degrees, operating by means of cold water, the pump L for the evacuation of
the cold gases, or rather the. driving cylinder L operating with cold air, and the
oxide of carbon generators O and O' and the air-pumps Z and Z¹, figure 2; which
feed these generators when operated with pressure.
The cylinders of the motor being single-acting, a complete motor naturally
comprises two cylinders and connections.
As shown in Figure 2, the four cylinders A L, A' L' are arranged in one single
row so that the piston-rods C and M act directly through the medium of connect-
ing-rods D, N upon the driving-shaft X X, by which means a continuous and
uniform motion of the motor is obtained.
The pistons P and P' actuated by the cooled gases on their exit from the
apparatus have for their object to effect the displacement of the large pistons B
and B. The latter have refractory coverings enabling them to bear the high
temperature to which they are subjected.
The two pistons P P¹ are acted upon constantly and in turn by the cooled gaseous
products, determined quantities of which they allow to escape through clack-valves
arranged in their bodies, or in any other suitable manner, while the remaining
portions are alternately forced into the recuperators where they are again heated
in order to return above the pistons B B₁ of the apparatus, being mixed with the
heated gases coming from the generators through the orifice V.
This enormous augmentation of volume in this latter case produces the great
power of the engine. The air-pumps Z Z' merely serve to convey into the oxide of
carbon generators the air necessary for restoring the lost heat.
The cylinder A has a covering 6 of fire-bricks, perfectly cemented, of about
20 centimeters thickness at all parts exposed to high temperature.
The piston B has a rod C and is steadied by stays a a. The said piston-rod
passes through a guide e c d for maintaining it invariably in a vertical line parallel
with the sides of the piston B.
The piston B has also a cast-iron prolongation i without a refractory lining, which
is strengthened by ribs which enable the air to circulate freely and to cool the
sides.
m indicates a circular groove in the piston, in which is placed a packing ring n of
bronze or other suitable material which slides upon the prolonged cast-iron sides
of the cylinder A. This vertical circular wall upon which the ring n slides is.
lubricated, and is cooled by a continuous current of cold air circulating through
the jacket oo. This cold air is supplied by the air-pump Zand is heated in the
jacket before passing to the oxide of carbon generators.
When necessary the cooling of this part of the cylinder A is effected by means of
a current of cold water.
The pipe I conducts the gases cooled below 300 degrees into the cold water
refrigerator J, and the tubes K conduct the cooled gases into the cylinder L, the

page_text: piston-rod M of which has a guide r. N is the connecting rod of the small
(cylinder.
V is the inlet for the gases of the generator O, and T is the inlet for the
atmospheric air which serves for the combustion of these gases.
: So far it has been supposed that the motor operates with an internal pressure
of two atmospheres, the pump Z conveying the air against this pressure into the
oxide of carbon-generator O.; but it is obvious that it can also be worked at the
.pressure of the atmosphere, by closing the lower part of the small cylinder L (the
rod M of the piston P traversing in that case a stuffing-box) and by creating a
vacuum below the piston P by means of the air-pump Z which would otherwise be
[of no use. The portion of the gases which it is desired to evacuate pass through
clack valves arranged for this purpose in the piston P.
•
It will be understood that the apparatus can also be arranged in such a manner
that the vacuum can be created above the piston P, and the atmospheric pressure
existing on the lower side of the piston be utilized, in order to obtain the motive
power of the apparatus. This latter method is perhaps preferable, provided there
is no pressure in the gas producing apparatus, because the necessity of producing
oxide of carbon under a pressure of two atmospheres is obviated.
Having now particularly described' and ascertained the nature of the said
invention and in what manner the same is to be performed as communicated to
me by my foreign correspondents I declare that what I claim is
First. The improvements above described relating to the production of motive
power, and based essentially upon the direct employment of the gases of combustion
at their maximum temperatures, whilst heretofore the temperature of these gases has
been considerably lowered.
Second. The apparatus formed in two portions both of which operate upon one
crank shaft and each of which comprises an air pump, an oxide of carbon generator,
a large cylinder having a refractory lining with which the gases at high temperature
come into contact; a small driving cylinder operating at a less high temperature;
and recuperators and refrigerators the whole constructed substantially as above
described and as represented in the accompanying drawing.
Third. The arrangement above specified, which permits the operation of the
apparatus at atmospheric pressure, by creating a vacuum below the driving piston by
'means of the air-pump, which, when the operation takes place at a higher pressure,
serves to force the air for supporting combustion into the oxide of carbon generators
and the burners.
Fourth. The construction and arrangement above described and represented in
the accompanying drawing, of the cylinders of the apparatus, of the recuperators
and of the refrigerators, and especially the arrangement for keeping the joints and
surfaces of the large cylinders cool to permit the regular operation of the
apparatus.
a