Year: 1886

page_text: I, WALLACE FAIRWEATHER C.E. of 135 Buchanan Street, in the City of Glasgow,
Fellow of the Institute of Patent Agents, do hereby declare the nature of this
invention, (a communication to me from abroad by George H. Babcock of Plainfield
in the County of Union and State of New Jersey, United States of America,
Engineer,) and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:-
Before proceeding to a description of my invention I will observe that there are
two classes of air engines one known as the "Stirling" engine, in which a given
quantity of air is alternately heated and cooled, producing a variation in pressure
and thus developing energy, and the other is what is known as the "Ericsson"
engine, in which a quantity of atmospheric air is taken in, heated, expanded, and
rejected at each revolution. My invention relates to the first class, in which the
saine air is alternately heated and cooled in the engine, which offers the advantage
by using a highly compressed fluid, of securing a large power within a small
space and also the advantage of a higher efficiency of the fluid owing to a less loss
of heat. There is also another division by which air engines may be classed, the
first A known as the "Cailey " engine, in which the products of combustion are
used directly within the cylinder which secures a high rate of economy over the
second class B comprising those in which the air is heated by convection through
a heating surface. Hitherto no practically successful effort has been made to com-
bine this class A with the "Stirling" engine in which the same air is alternately
heated and cooled. My invention relates to such a combination, whereby the
advantages of both classes are attained in one engine, with additional advantages
due to the combination, and to a certain method of energizing a volume of actuating
fluid which is repeatedly used within the engine by introducing hot products of
combustion into said fluid at intervals and cooling said fluid between the intervals
of introduction of the said hot products.
My invention consists in mingling hot products of combustion with the fluid in
the engine, and also the same in combination with means for removing a portion of
n

page_text: the fluid whereby the total quantity within the engine remains constant or nearly
so; also in certain means for removing the water which may be condensed from
the products of combustion so mingled with the fluid in the engine; also in certain
means for controlling the speed of such an engine; and also in various combinations
and arrangements of the parts for the better carrying out of the principle involved.
In the accompanying drawings which illustrate my invention figure 1 is a vertical
sectional view of a modification of my improved air or gas engine and figures 2
and 3 are detail views which are hereinafter referred to.
A is a cylinder which I call a changing cylinder, and A¹ a plunger working
within said cylinder freely but nearly air-tight. B is a working cylinder, in which
the plunger B is fitted to work tightly. These plungers are made in the well
known manner of similar engines, having a deep portion fitted with some non-
conducting substance to protect the wearing surface from the direct action of the
heated fluid. The lower portions A and B of these cylinders are surrounded by
water jackets for conveying away the surplus heat thereof and keeping the surfaces
sufficiently cool to admit of lubrication. C is what is known as a regenerator
consisting of a collection of plates of iron or other material with small interstices.
through which the fluid passes on its way to and from the hot end of the cylinder,
.which regenerator serves the purpose of retaining a portion of the heat of the hot
gases and restoring the same to the cold gases in a manner well known in similar.
engines. D is a refrigerator consisting of a series of small tubes surrounded by
water, through which the air passes on its way to the cold end of the cylinder, for
the purpose of taking out such heat from the air as has not been absorbed by the
regenerator; this is also a well known device.
E is the crank shaft having two cranks placed at an angle to each other and
connected in the ordinary way to the two pistons A¹ and B¹ transmitting their
power and controlling the time of their motions. Fig. 3 shows the relation of
these cranks one with the other. I find in practice the angle of 75 degrees gives.
the best results, but this may be varied as circumstances require. F is a furnace
wherein the combustion takes place, and having passages or ports f, connecting
it with the interior of the cylinders A and B. This furnace F may be of any
size and burn any fuel as is found to be practicable, but I prefer to make it as
shown, quite small and to burn therein some form of hydro-carbon fuel as herein-
after described. G is a pump automatically operated by a connection with the
engine, and here shown as connected with an eccentric H on the main shaft E, for
the purpose of supplying the fuel to the furnace F. The connection of this pump G
with the shaft is shown more fully in Fig. 2, in which the eccentric H is connected
to one end of a link, I, the other end of which is jointed to a distance-rod H¹
attached to the shaft or any other convenient stationary point. It will be seen
that by the variation of the position of the link I relative to the plunger, G¹, any
amount of stroke may be given to the plunger G₁ from the full throw of the
eccentric to nearly or quite none. The length of the distance-rod H¹, bears such
relation to the plunger G¹, and the eccentric H, that the plunger G₁ is caused to
approach to nearly the inner end of the barrel of the pump G at each stroke,
whatever may be the length of the stroke. Instead of varying the stroke of the
pump G the same object may be attained by connecting therewith a vessel, con-
taining a piston or other means of varying the size thereof, into which vessel a
portion of the gas within the pump G, may be allowed to expand as it is com-
pressed, and the amount of fuel pumped into the engine may thereby be reduced.
The position of the piston within this vessel or supplementary chamber may be
determined by a governor, so as to automatically control the amount of gas
delivered while the stroke of the pump remains constant.
The valves g and glare of ordinary construction and need not be specifically
described. A pipe K leads from the pump G to the furnace F. Lis an air pump
for the purpose of supplying air for the proper combustion of the fuel within the
furnace F. It is of ordinary construction having valves, and plunger L' and
is driven preferably by an eccentric M on the main shaft. The stroke of this

page_text: pump L may be made to vary in the same manner as the pump G, or the amount of
air delivered therefrom may be otherwise varied as above described in connection
with the said pump G; but I prefer that it should have a constant stroke as
shown. A pipe N, leads from the air pump L, to the furnace F. Any of the well
known means may be employed for igniting the fuel within the furnace, but when
the interior of the furnace, which consists of a refractory substance like fire brick,
has once become heated to incandescent temperature the fuel will ignite spontane-
ously upon coming in contact therewith. I provide a valve O, in the passage a
through which the air passes to and from the cold end of the changing cylinder A,
which valve is operated by an eccentric O¹ mounted on the main shaft, or by other
means. This valve O is similar to the slide valve of a single acting steam engine
and admits a portion of the air or actuating fluid from the passage a, at each
revolution into the annular space b, formed between the cylinder B2, and the
trunk of the plunger B¹. This annular space may bear any desired proportion of
area to the area of the cylinder B to admit of any desired expansion to the portion
of the air which is admitted thereto by the valve O. The passage a is formed
with a depression or pocket a² in which any water condensed from the products of
combustion will accumulate and in which the valve O is situated, so that when
any water accumulates therein it will be blown out on the opening of the valve O.
A petcock X is also provided for removing such water at will. I also provide the
passage a with a throttle valve P, by closing which, more or less, the resistance of
the passage of the air or gas from the cold to the hot end of the cylinder A, or
vice versa, may be increased or diminished. The stem of this valve P, extends
out through a proper stuffing box and is connected through an arm, p, to a centri-
fugal governor Q, whereby the valve P is caused to be operated automatically by
the varying speed of the engine.
Another centrifugal governor, R, Fig. 2. is connected to the distance-rod H¹ in
such a manner that when the speed of the engine increases, the link I is drawn
over to reduce the throw of the plunger G', and thereby decreases the supply of
fuel to the furnace F. This governor, R, instead of being attached to the distance
rod H¹, may be connected to a variable chamber communicating with the pump, G,
or with any other means for controlling the supply of gas to the furnace.
I prefer to graduate the two governors R and Q relatively to each other in such
a manner that the governor R shall have completed its action before the speed has
increased to an extent to cause the governor Q to operate the valve P, so that in
controlling the speed of the engine the amount of fuel supplied to the furnace F,
will be thus reduced to a minimum, and if that be not sufficient then the throttle
valve P will be brought into action to increase the internal resistance of the
engine.
The operation of the engine is as follows:-
The interior of the cylinders A and B, the regenerator C, tubes D, and passage a
and furnace F, all communicating, are first filled with a volume of atmospheric air
or other gas, at any desired pressure by a pump or otherwise. The engine being
turned over by hand, or by any other convenient means, the plunger A¹, is caused
to descend and force the air which is below it through the refrigerator D and
regenerator C into the upper portion of the cylinder A. At the same time the fuel
pump G and air pump L, deliver a portion of gas or other fuel with the necessary
oxygen for its combustion into the furnace F where it is ignited and the products
of combustion passing through the ports f mingle with the air or gas within the
engine, causing the whole to become heated and the pressure thereof to increase.
This forces the plunger B' to descend, exerting the energy derived from such
pressure upon the crank E². The plunger A' now returns by the revolution of the
crank shaft and crank E, forcing the heated air or gas in the upper part of the
cylinder A down through the regenerator C which absorbs the larger part of
the heat therein, through the refrigrator D, which takes away the balance of the.
heat, into the lower end of the cylinder A, thus reducing the temperature and
the pressure, when by the revolution of the crank E³, the plunger B¹, is forced back

page_text: into the cylinder B driving all the air therein also through the regenerator C and
refrigerator D, into the lower part of the cylinder A². The valve O having opened
for a short time at the commencement of the return stroke of the plunger B¹,
admitted a certain volume of the air from the passage a, into the annular space b
and then closed allowing the air which was thus admitted to b. to expand and
assist in the return of the plunger B', this air admitted to the space b being sub-
sequently exhausted through the valve O. Meantime the plungers of the pumps G
and L have descended and taken in a fresh supply of gas and air. By the
continual revolution of the shaft E, the plunger A is now brought again to the
lower end of the changing cylinder, forcing the cold air therefrom around through
the refrigerator D and regenerator C into the upper end of the cylinder A in which
passage it has taken up the heat which was stored in the regenerator C and been
increased in pressure. At the same time the fuel pump G and air pump L have
delivered another supply of fuel to the furnace F, and the products of combustion
from it have passed in and mingled with the air, or gas, within the engine, still
further increasing its heat and pressure, by which the plunger B', is forced outward
as before.
This cycle of operations continues regularly with each revolution. The
valve is so arranged that it will admit only a definite amount of air from the
passage a, into the annular space b which volume is less than the volume of
the pump L. It will therefore be seen that so long as the pressure within the
passage a, bears the same inverse ratio to the volume of air admitted into the
space b, that the atmospheric pressure bears to the volume of the pump L,
the quantity of fluid within the engine will remain constant.
It will also be seen,
when the valve O is adjusted to admit into the annular space b a definitely smaller
volume of air than the volume of the air pump L; that if the pressure in the
engine A, B, is such that this volume of air so admitted into b, does not weigh
the same as the volume of air which is pumped into the furnace F, through the
pump L, the pressure in A, B, must increase with each stroke, until the equilibrium
between the amount of air delivered by the pump L and the amount of air
removed by the valve O is secured.
The furnace F may be heated up before starting the engine by building a fire
within the same, or by a gas jet or by introducing a live hot coal just before
starting the engine. It may also, in some cases, be made sufficiently large to
receive a quantity of solid fuel in which case the pump G can be dispensed with,
the pump L furnishing air for the combustion of the fuel within the furnace as
rapidly as the needs of the engine require.
The advantages due to my invention are:-
The heat being applied directly to the gases within the engine is all utilized
with the exception of the small proportion, usually about one tenth, which is
rejected through the refrigerator D, or that which is lost by radiation. That
portion of the fluid which is removed by the valve O and annular space b, it will
be noticed, is taken from the cold end of the engine after it has passed through the
regenerator C, wherein a large portion of its heat has been stored or trapped. This
air, therefore, carries off none of the heat supplied to the engine, as does the
exhaust of an ordinary gas engine or any form of the "Cailey " engine heretofore
known. By the use of the same fluid in the engine, stroke after stroke, it requires
but a small proportion of the highly heated products of combustion to be mingled
therewith in order to impart the required amount of heat. The air pump L is
therefore small in proportion to the capacity of the engine and the loss from
compressing a large amount of air at each stroke is saved, and the cost of com-
pressing the air compressed by the pump L is nearly repaid by the expansion of
the air in the annular space b. It is evident that this annular space b can be
replaced by an independent piston working in another cylinder or it could be
replaced by inclosing the lower portion of the pump L, but I prefer to employ the
annular space as shown.
A difficulty which attends nearly all air and gas engines exists in consequence of
the resistance of the compression of the air in the cylinder in some portion of the

page_text: revolution, and this difficulty increases greatly in engines in which a high pressure
is used. One of the advantages due to my invention is that the engine may be
started at atmospheric pressure, with little resistance and after a few revolutions
the pressure will accumulate in consequence of the pump L putting in more air
than the valve O lets out, which will continue until the proper pressure is attained,
and the engine is ready to work at its full load.
In practice it will probably be found best to employ two such engines as herein
described, working upon opposite cranks or through beams, so that the normal
pressures upon the working pistons will balance each other, and the working
piston B¹, will therefore not be compelled to be forced back against the back
pressure by the momentum of the fly-wheel. I have preferred, however, to
represent it in this case as a single engine for the sake of simplicity in the
drawings.
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 I declare that what I claim is
1. In an air or gas engine in which the same actuating fluid is repeatedly
heated and cooled, the combination with a furnace communicating by ports or
passages with the hot chamber behind the working piston or plunger, and within
which chamber the actuating fluid is expanded while doing work, of a regenerator
for intermittingly cooling the said fluid after it has done its work, said regenerator
retaining the heat for subsequent use, and a valve for removing the water condensed
from said products of combustion, substantially as set forth.
2. In an air or gas engine in which the same actuating fluid is repeatedly heated
and cooled, the combination with a furnace communicating by ports or passages
with the chamber containing the said fluid, so that the products of combustion
may mingle with and thus heat the same, of a valve for removing the water
which may be condensed from the said products of combustion, substantially as
set forth.
3. In an air or gas engine in which the same actuating fluid is alternately heated
and cooled and in which hot products of combustion are mingled with said fluid
within the engine, the combination of a valve for removing a portion of the cooled
fluid from the engine at intervals, and a pocket or reservoir for collecting the
water which may be condensed from the products of combustion, substantially as
set forth.
4. In an air or gas engine in which the same actuating fluid is repeatedly heated
and cooled, the combination of a piston or plunger for changing the fluid to or
from the hot and cool portions of the engine, a hot chamber in which the pro-
ducts of combustion are expanded, a furnace communicating with said hot chamber
and adapted to mingle hot products of combustion with the fluid therein, a working
piston or plunger operating in said hot chamber and adapted to utilize directly
the expansive energy of the heated fluid, and a valve for removing the water
condensed from said products of combustion, substantially as set forth.
5. In an air or gas engine in which the same actuating fluid is repeatedly heated
and cooled, the combination of a piston or plunger for changing the fluid to or
from the hot and cold portions of the engine, a working piston or plunger for
directly utilizing the expansive energy of the heated fluid, a hot chamber in which
said working piston operates, a furnace communicating with the said hot chamber,
a regenerator arranged to retain a portion of the heat of the fluid when the latter
is on its way from the hot to the cool portion of the engine and to restore the
beat to said fluid on its return to the hot portion of the engine, and a valve
for removing the water which may be condensed from said products of combustion,
substantially as set forth.
6. In an air or gas engine in which the same actuating fluid is repeatedly
heated and cooled, the combination of a piston or plunger for changing the fluid
to or from the hot and cold portions of the engine, a working piston or plunger for

page_text: directly utilizing the expansive energy of the heated fluid, a hot chamber in which
said working piston operates, a furnace communicating with the said hot chamber,
a regenerator arranged to retain a portion of the heat of the fluid when the latter
is on its way from the hot to the cool portions of the engine and to restore the
heat to said fluid on its return to the hot portion of the engine, a refrigerator for
conveying away such portions of the heat as is not stored up by the regenerator,
and a valve for removing the water condensed from the products of combustion,
substantially as set forth.
7. In an air or gas engine in which the same actuating fluid is alternately heated
and cooled, a contracted chamber or passage through which the said fluid is forced
as it passes to and from the hot and cold ends of the engine, said chamber or
passage being provided with a valve for regulating the speed or passage of the said
fluid, substantially as set forth.
8. In an air or gas engine in which the same actuating fluid is alternately heated
and cooled, a contracted chamber or passage through which the said fluid is forced
as it passes to and from the hot and cool ends of the engine, said chamber or
passage being provided with a valve for regulating the speed of passage of said
fluid, combined with a governor for automatically controlling said valve, substan-
tially as set forth.
9. In an air or gas engine in which the same actuating fluid is alternately heated
and cooled, the combination of a furnace communicating with the chamber con-
taining the said fluid, and thus adapted to mingle hot products of combustion
with the latter, one or more measuring devices, as air pumps, for regulating the
supply of hot products of combustion, and a valve for regulating the resistance of
the fluid in its passage to or from the hot and cool ends of the engine, substantially
as set forth.
10. In an air or gas engine in which the same actuating fluid is alternately
beated and cooled, the combination with a furnace communicating with the chamber
containing the said fluid and thus adapted to mingle the hot products of combus-
tion with the latter, one or more automatically controlled measuring devices, as air
pumps, for regulating the supply of the hot products of combustion, a valve for
regulating the resistance of the fluid in its passage to or from the hot and cool
ends of the engine, and a governor for automatically controlling said valve,
substantially as set forth.
11. The method herein described of operating an air or gas engine, by inter-
mittingly mingling hot products of combustion into a volume of actuating fluid
within the engine, expanding the same directly against a working piston while
thus heated, afterward cooling said fluid in the interval between the introduction
of hot products of combustion and removing from the engine the water which may
be condensed from the products of combustion, substantially as set forth.
12. The method herein described of operating an air or gas engine, by inter-
mittingly mingling liot products of combustion with a volume of actuating fluid
within a hot chamber, expanding said fluid in the developinent of power, directly
against a working piston, transferring a part or all of said fluid to a cool portion of
the engine, compressing it therein while cool, and removing from the engine the
water which may be condensed from the said products of combustion, substantially
as set forth.
13. The method herein described of developing power for operating air or gas
engines, consisting in partly heating the actuating fluid, which is repeatedly used
within the engine, as it is passed from the cool to the hot part of the engine,
further heating the said fluid and thus fully energizing the same by mingling bot
products of combustion therewith, utilizing its developed energy by expanding the
heated fluid directly against the working piston or plunger, afterwards cooling said
fluid as it is passed from the hot to the cool part of the engine, and while thus
cooled, removing therefrom the water which may be condensed from the said
products of combustion, substantially as set forth.

page_text: 14. The method herein described of operating an air or gas engine, and of
regulating the pressure of the actuating fluid thereof, by intermittingly mingling
hot products of combustion with the actuating fluid, utilizing the developed energy
thereof by expanding, in its heated condition, the same directly against a working
piston or plunger, cooling the said actuating fluid thereafter and between the
intervals of introduction of said hot products of combustion, and intermittingly
removing a certain desired portion of the cooled fluid, together with the water
condensed from said products of combustion, substantially as set forth.
Dated this eleventh day of January 1886.