IMPROVEMENTS IN MOTOR ENGINES WORKED BY COMPRESSED AIR OR OTHER ELASTIC FLUID UNDER HIGH PRESSURE."
Year: 1880

page_text: LETTERS PATENT to Frederick Edward Blackett Beaumont, of No. 4, Broad
Sanctuary, Westminster, in the County of Middlesex, for an Invention of
"IMPROVEMENTS IN MOTOR ENGINES WORKED BY COMPRESSED AIR OR OTHER
ELASTIC FLUID UNDER HIGH PRESSURE."
PROVISIONAL SPECIFICATION left by the said Frederick Edward Blackett
Beaumont at the Office of the Commissioners of Patents on the 7th February
.1880.
FREDERICK EDWARD BLACKETT BEAUMONT, of No. 4, Broad Sanctuary,
Westminster, in the County of Middlesex. "IMPROVEMENTS IN MOTOR ENGINES
WORKED BY COMPRESSED, AIR OR OTHER ELASTIC FLUID UNDER HIGH PRESSURE.”
In the Specification to Letters Patent granted to me on the 1st January 1876,
No. 7, was described a method of equalising the power of an engine worked by
elastic fluid stored at considerable pressure in a reservoir, by causing the said
fluid to act by expansion successively in two or more cylinders of increasing
diameters, so arranged that in the first instance when the air is at high pressure,
only the cylinder of small diameter is put in direct communication with the
reservoir, but that as the air pressure decreases the cylinder or cylinders of
larger diameter is or are consecutively put in direct communication with the
reservoir.
One part of the present Invention relates to improved means for effecting such
successive communication between the reservoir and the cylinder or cylinders of
larger diameter after the pressure has become reduced to a certain extent.
In the motor-engine described in the before mentioned Specification, this
communication was established by means of a series of slides respectively covering
ports leading from a channel that communicated directly with an air-reservoir to
each of the cylinders.
According to the present improvement the cylinders being double acting, the
air reservoir communicates directly with the smallest or high pressure cylinder
only, by passages governed by lift valves; this cylinder communicates by ports and
passages provided with: valves with the second cylinder, so that the compressed
air expands into the latter after doing duty in the former, and in like manner if

page_text: a third cylinder be employed the compressed air is admitted into this from the
second cylinder through ports and passages provided with valves. When by
continued working the pressure in the air reservoir has sunk to a certain extent,
the admission valves to the high pressure cylinder are raised and kept off their
seats, so that the compressed air then passes freely into both ends of this cylinder,
thereby putting its piston in equilibrio, and the air then finds its way through the
ports and passages connecting the first and second cylinders into the latter, the
piston of which is consequently then worked by the full pressure in the reservoir.
In like manner if a third cylinder be used the admission valves to the second
cylinder may also be raised off their seats when the air pressure has again sunk
below a certain degree, so as to allow the air from the reservoir to pass through
both the first and second cylinders to the third cylinder. In order to render the
expansion of the compressed air fully available I, according to another part of my
Invention, work the first cylinder with a cut-off, the mechanism for effecting which
is so arranged that the degree of expansion can be gradually diminished as the
air pressure in the reservoir decreases. For this purpose the admission lift valves
are worked by the middle of a double ended lever, one end of which is actuated
from an eccentric crank or cam on the engine shaft, so that if the other end of the
lever worked on a fixed fulcrum the valve would be raised off its seat during the
whole stroke, or nearly so, of the piston. The other end of the lever is however
not fixed, but supported by a roller resting upon a sliding piece to which a
reciprocating motion is imparted from the piston rod, and this sliding piece has at
a certain point a drop or incline, so that when by its motion this drop or incline
is brought under the roller, the end of the lever in dropping allows the valve
which had previously been raised by the action of the other end of the lever to
close on its seat so as to effect the cut off. On the return motion of the sliding
piece the one end of the lever is again raised by the incline, but the other end of
the lever being at that time moved or permitted to move in the contrary
direction the valve is not opened by such motion. By adjusting the position of
the sliding piece relatively to the end of the lever so as to bring the drop under
the lever at an earlier or later part of the piston's stroke, the period of the cut off
and degree of expansion can be correspondingly varied. When the cylinder, being
double acting, is provided with an admission valve at each end, both the sliding
pieces for the valves are adjusted by a rod screwed through them with right and
left handed screw threads, so that by turning the rod more or less the sliding
pieces are simultaneously adjusted to effect the cut off at the period required.
The above described arrangement for causing the admission valves to work
with variable cut off is also applicable to other constructions of motor engines, in
which air or other elastic fluid under compression is caused to operate by
expansion in one or more cylinders. The admission valves are so arranged as to
be pressed to their seats by the air pressure, and each has a spring to ensure quick
action and to keep the valve seated when there is no pressure. In order to reduce
the risk of leakage past the inlet valves of the first cylinder I make them with
double seatings, the one seating over an intermediate chamber, and the other
seating over the passage from this chamber to the cylinder. Also in order to
prevent displacement of the valve by the rush of high pressure air, I surround it
by a fence having through it passages so arranged that the impulse of the air on
the valve is balanced.
Another part of my Invention relates to means for imparting heat to the com-
pressed air, so as to compensate for the decrease of temperature resulting from its
expansion in the cylinders. For this purpose I provide a small steam boiler which
is connected with the passages leading into the working cylinder or cylinders by
means of pipes, having check valves so arranged that so long as the pressure of
the air in the cylinder is above that of the steam in the boiler the valves remain
closed and prevent the entrance of steam, but when by the expansion of the air its
pressure sinks below that of the steam, the latter opens the valves and mingles
with the air imparting heat to it I also provide the cylinders with casings

page_text: supplied with steam or circulating hot water from the boiler so as to impart heat
to the expanding air, the heat thus imparted being in many cases sufficient, without
having recourse to admixture of steam with the air as described above. Instead of
employing hot water for circulating through such casings, a liquid of a higher
boiling point, such as a saline solution, or oil, may be employed for that purpose.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Frederick Edward Blackett Beaumont in the Great Seal Patent
Office on the 5th August 1880.
FREDERICK EDWARD BLACKETT BEAUMONT, of No. 4, Broad Sanctuary,
Westminster, in the County of Middlesex. "IMPROVEMENTS IN MOTOR ENGINES
WORKED BY COMPRESSED AIR OR OTHER ELASTIC FLUID UNDER HIGH PRESSURE."
In the Specification to Letters Patent granted to me on the 1st January 1876,
No. 7, was described a method of equalising the power of an engine worked by
elastic fluid stored at considerable pressure in a reservoir, by causing the said fluid
to act by expansion successively in two or more cylinders of increasing diameters,
so arranged that in the first instance, when the air is at high pressure, only the
cylinder of small diameter is put in direct communication with the reservoir, but
that as the air pressure decreases the cylinder or cylinders of larger diameter is or
are consecutively put in direct communication with the reservoir.
One part of the present Invention relates to improved means for effecting such
successive communication between the reservoir and the cylinder or cylinders of
larger diameter after the pressure has become reduced to a certain extent.
In the motor-engine described in the before mentioned Specification this
communication was established by means of a series of slides respectively covering
ports leading from a channel that communicated directly with the air-reservoir to
each of the cylinders.
According to the present improvement, the cylinders being double acting, the air
reservoir communicates directly with the smallest or high pressure cylinder only,
by passages governed by lift valves; this cylinder communicates by ports and passages
provided with valves with the second cylinder, so that the compressed air expands
into the latter after doing duty in the former, and in like manner, if a third
cylinder be employed the compressed air is admitted into this from the second
cylinder through ports and passages provided with valves. When by continued
working the pressure in the air reservoir has sunk to a certain extent the admission
valves to the high pressure cylinder are raised and kept off their seats, so that the
compressed air then passes freely into both ends of this cylinder, thereby putting
its piston in equilibrio, and the air then finds its way through the ports and
passages connecting the first and second cylinders into the latter, the piston of
which is consequently then worked by the full pressure in the reservoir. In like
manner, if a third cylinder be used, the admission valves to the second cylinder

page_text: may also be raised off their seats when the air pressure has again sunk below a
certain degree, so as to allow the air from the reservoir to pass through both the
first and second cylinders to the third cylinder. In order to render the expansion
of the compressed air fully available I, according to another part of my Invention,
work the first cylinder with a cut off, the mechanism for effecting which is so
arranged that the degree of expansion can be gradually diminished, as the air
pressure in the reservoir decreases. For this purpose the admission lift valves are
worked by the middle of a double ended lever, one end of which is actuated from
an eccentric crank or can on the engine shaft, so that if the other end of the lever
worked on a fixed fulcrum the valve would be raised off its seat during the whole
stroke, or nearly so, of the piston. The other end of the lever is, however,
not fixed, but supported by a roller resting upon a sliding piece, to which a
reciprocating motion is imparted from the piston rod, and this sliding piece has at
a certain point a drop or incline, so that when by its motion this drop or incline is
brought under the roller the end of the lever in dropping allows the valve, which
had previously been raised by the action of the other end of the lever, to close on
its seat, so as to effect the cut off. On the return motion of the sliding piece the
one end of the lever is again raised by the incline, but the other end of the lever
being at that time moved or permitted to move in the contrary direction, the valve
is not opened by such motion. By adjusting the position of the sliding piece
relatively to the end of the lever, so as to bring the drop under the lever at an
earlier or later part of the piston's stroke, the period of the cut off, and degree of
expansion can be correspondingly varied. When the cylinder, being double acting,
is provided with an admission valve at each end both the sliding pieces for the
valves are adjusted by a rod screwed through them with right and left handed
screw threads, so that by turning the rod more or less the sliding picces are
simultaneously adjusted to effect the cut off at the period required.
The above described arrangement for causing the admission valves to work
with variable cut off is also applicable to other constructions of motor engines in
which air or other elastic fluid under compression is caused to operate by expansion
in one or more cylinders. The admission valves are so arranged as to be pressed
to their seats by the air pressure, and each has a spring to ensure quick action and
to keep the valve seated when there is no pressure. In order to reduce the risk of
leakage past the inlet valves of the first cylinder, I make them with double seatings,
the one seating over an intermediate chamber and the other seating over the passage
from this chamber to the cylinder. Also in order to prevent displacement of the
valve by the rush of high pressure air, I surround it by a fence having through it
passages so arranged that the impulse of the air on the valve is balanced.
Another part of my Invention relates to means for imparting heat to the coin-
pressed air so as to compensate for the decrease of temperature resulting from its
expansion in the cylinders. For this purpose I provide a small steam boiler, which
is connected with the passages leading into the working cylinder or cylinders by
means of pipes having check valves so arranged that so long as the pressure of the
air in the cylinder is above that of the steam in the boiler, the valves remain closed
and prevent the entrance of steam, but when by the expansion of the air its
pressure sinks below that of the steam, the latter opens the valves and mingles
with the air, imparting heat to it. I also provide the cylinders with casings
supplied with steam or circulating hot water from the boiler, so as to impart heat
to the expanding air, the heat thus imparted being in many cases sufficient
without having recourse to admixture of steam with the air as described above.
Instead of employing hot water for circulating through such casings a liquid of
a higher boiling point, such as a saline solution, or oil, may be employed for that
purpose.
The accompanying Drawings represent a construction and arrangement of a
locomotive according to my Invention, worked by compressed air contained in a
strong reservoir carried by the locomotive, and constituting a store of force
available for propelling the locomotive over considerable distances. I will first

page_text: describe the general arrangement of the locomotive, referring to Fig. 1, which is a
longitudinal section, and Fig. 2 an end view. A framing A supported by springs
on four wheels B carries the reservoir C containing the compressed air and two
complete engines worked by it. Each engine consists of two double acting
cylinders, one of them E a small cylinder which receives for each stroke a charge
of compressed air from the reservoir C, and the other F a larger cylinder in which
the air discharged from the smaller cylinder expands performing work, and from
which it is discharged as waste. The admission of air to the smaller cylinder E is
regulated by an adjustable cut off apparatus, hereafter to be described, so that
notwithstanding considerable change of pressure in the reservoir the eugine power
can be maintained uniform or nearly so. Thus when the reservoir at first starting
contains air at very high pressure the cut off is adjusted so that at each stroke the
small cylinder receives a very small charge, which expands therein propelling its
piston, and afterwards expands farther in the larger of the two cylinders. When
on the other hand the pressure in the reservoir has become greatly reduced by
expenditure of air the cut off is adjusted so as to admit a larger charge into the
small cylinder, that is to say, to admit air throughout a greater portion of the
stroke of its piston. When the pressure in the reservoir is so far reduced that the
action on the smaller piston gives very little power the supply passages to the
smaller cylinder are, by means hereafter to be described, kept open, so that the air
from the reservoir acts directly on the piston of the larger cylinder, the smaller
piston in that case working idly. This arrangement can also be temporarily adopted
when energetic action is required, as for starting the locomotive, the full pressure of
the air in the reservoir being throughout one stroke or more permitted to act on
the larger piston. The pistons of the two cylinders are connected in the usual way
to cranks on the driving axle, those two cranks being set opposite to one another,
so that when one of the two pistons is advancing the other is retreating. By this
arrangement the air discharged from each end of the small cylinder passes directly
into the corresponding end of the larger cylinder, this arrangement shortening the
passages from the one cylinder to the other and simplifying the valves which
govern them. The other pair of cylinders, arranged in a similar manner, act on
cranks on the same driving shaft, those cranks being likewise opposite to one
another, but at right angles to the cranks of the former pair of cylinders.
The driving axle has on it two sets of eccentrics working link motions of ordinary
construction, one for each pair of cylinders, these link motions being connected in
the usual way to a hand lever for starting, stopping, or reversing.
As the air, when it expands performing work in the cylinders, would undergo
considerable reduction of temperature and proportionate reduction of pressure, I
provide means of sustaining its temperature during its expansion. For this purpose
I mount in a convenient part of the locomotive, as at D, a small boiler for generating
a small quantity of steam, which is led by a pipe to hollow casings enclosing the
working cylinders. The steam partly condenses in these casings, keeping the
cylinders warm, and the water of condensation returns by a pipe to the boiler, to
be again vaporised and circulate through the casings. It is of advantage to lead
the air discharged from the larger cylinders to the ash pit of the boiler, which is
provided with an escape valve, so that the discharged air can, when required, be
made, by closing more or less the escape valve, to act more or less as a blast for the
boiler fire.
In order to avoid complicating the Drawings I have not shewn in them the air
or steam pipes connected with the boiler, as their arrangement may be readily
understood.
The wheels B are coupled by external connecting rods in the usual way, so that
they all act as driving wheels, and these connecting rods, as well as the wheels, are
enclosed within casings A¹.
Having thus described generally the construction and arrangement of a locomotive
according to my Invention, I will now explain the arrangement and action of the
valves by which the air is admitted to and emitted from the working cylinders of

page_text: each engine, referring to the following detail Drawings:-Fig. 3, a transverse section
through a pair of the cylinders and their valves; Fig. 4, a transverse section, and
Fig. 5 a part longitudinal section of the cut off apparatus for the small cylinder;
Fig. 6, a side view shewing the levers for working the valves that govern the
passages from the small to the large cylinder; and Fig. 7 a side view shewing the
levers which work the valves that govern the discharge from the larger cylinder.
In these Figures E is the small cylinder and F the large cylinder; e is the pipe
leading from the reservoir C to each end of the small cylinder, the passage in each
case being governed by a double valve, a lower valve e¹ pressed up against its seat
by a spring, and an upper valve e² having a stem which passes through a stuffing
box and is pressed upwards by a spring e. It will be observed that the two valves
e¹ and e² are not rigidly attached to one another, but that the lower one e¹ is merely
opened by the pressure of the upper valve upon it, the lower valve having freedom
to close tightly when the upper valve seats itself. Both valves are opened by the
downward movement of the stem e³, and according as this movement is more or
less prolonged a greater or less charge of compressed air will be admitted to the
small cylinder E, or, in other words, the movement of the stem es determines the
cut off. This movement is effected and regulated in the following manner:-In
the stem es is jointed a lever es which at one end carries a roller e, and at the other
end is acted on by an arm of a lever G which is worked by a connecting
rod g from a slide gl moved by the eccentric link g². The piston rod of the smaller
cylinder E, by means of a link h (see Fig. 1), works a lever H, and this lever, by
means of a link 2, works a sliding rod h³; this rod is connected to the link h² by a
swivel joint, so that it can be caused to revolve by gearing h* worked from a hand
wheel h³. The rod h³ is screwed over two parts of its length with right and left
threads working respectively in female threads in blocks he (see Figs. 4 and 5)
which move in guides parallel to the axis of the cylinder. By turning the hand
wheel h³, and thereby causing the rod h³ to revolve in either direction, the two
blocks he can be made to approach towards each other or to recede from one another,
whilst they also continue to reciprocate to and fro along with the rod h³, which
reciprocates in accord with the piston of the small cylinder E, but with a much
smaller extent of stroke, as determined by the proportions of the lever H. The
rollers e bear against the under faces of the blocks, and therefore if, while either
of them so bears, an arm of the lever G depresses one end of the lever e³, the middle
of the lover e is necessarily depressed, moving down the stem e³ and opening the
valves e² and e¹, so as to admit a charge of air to the small cylinder E. The piston
of that cylinder moving causes the rod h³ and block also to move, and when the
block ho has moved so far that the roller e no longer bears against it, then the lever
e is left free and the valves e¹, e², close, cutting off the supply to the cylinder E.
Thus when the hand wheel 5 is turned in the one direction, causing the blocks h
to approach towards each other, the cut off takes place at an earlier period of each
stroke of the small piston, and when the hand wheel is turned in the opposite
direction the cut off takes place at a later period. The one hand wheel h³, by means
of the gearing h', serves to turn the rods h³ of both engines simultaneously, and thus
the attendant can vary the expansion in the small cylinders to suit the state of the
pressure in the reservoir C.
Besides being enabled thus to vary the expansion, the attendant can at any time
by means of a handle k keep open the supply valves e¹ and e², rendering the small
pistons idle and admitting air at the full pressure of the reservoir to act on the
larger pistons. For this purpose the handle is connected to a lever on a rocking
shaft K, an arm on which is linked to levers that engage in the stems e³, so that
when the handle k is pulled, the four stems e³ are simultaneously depressed, and
consequently the four sets of valves c', e², are opened. Thus when the pressure
acting in the small cylinders is insufficient to start the locomotive, the attendant
by pulling the handle k can admit the air to act in the larger cylinders at its full
pressure, the small pistons being for the time in equilibrio.
The valves f, whereby the air passes from the small cylinder E to the large

page_text: cylinder F, are kept closed by springs f¹, and are opened alternately by the levers ƒ³
acted on by the levers f³ which are worked from the eccentric link and lever G, as
shewn in Fig. 6. And in like manner the valves f* which govern the final
discharge of air from the large cylinders F are kept closed by springs f6, and
opened alternately by the levers ƒ³, ƒ8, which are worked also from the eccentric
link, as shewn in Fig. 7.
It will be seen that by the different arrangement of the levers actuating the
several admission valves of each compound engine, they are all enabled to be
worked by one and the same shaft and lever G.
The spaces d, shewn in Fig. 3, constitute the casings supplied with steam, as above
described, for the purpose of warming the cylinders E, F, and the air expanding in
them.
may
A small hole governed by a spring check valve, as indicated by the dotted lines
d' in Fig. 3, may form a communication from the steam space d to the passage
leading into the larger cylinder F, so that when the pressure of the air supplying
that cylinder is considerably reduced by expansion, a small quantity of steam may
mix with it as above described. Instead of or in addition to the passage d' there
be an opening into the cylinder F governed by a spring check valve f, so that if
the pressure in the cylinder F should be below that of the atmosphere, a little air
can enter the cylinder from outside. Brakes of any suitable kind may be applied
to the wheels, the brake levers being worked by treadles L situated conveniently
for the attendant or driver who commands the starting and stopping lever, and
regulates the expansive action, as described above.
Although I have shewn in the Drawings an arrangement of locomotive suitable
for being connected to other vehicles, such as tram cars, it may be readily under-
stood that the construction and arrangement could be varied so as to accommodate
the reservoir and engines, in or under the body of the vehicle itself, the general
principles of action and arrangement of the valves and their movements remaining.
such as I have described them. The air reservoir which I have shewn as a single
strong vessel, may be subdivided into several smaller vessels. A convenient and
strong form that has been employed is that of a number of closed tubes communi-
cating with one another. I have mentioned steam as being employed for
maintaining the temperature of the air cylinders. In cases where the boiler is at
a sufficiently high level relatively to the cylinder casings, these might merely have
hot water circulating through them, or instead of water there might be a saline
solution, or oil or other liquid having a boiling point higher than water. The pipe
conveying the air from the reservoir to the cylinders may be heated by passing it
through the hot casings so as to warm the air before it begins to perform work.
Although I have described my Invention as being more particularly applicable to
locomotive or traction engines, yet it will be evident that it is also applicable as a
motor engine for propelling boats or for working in mines or other localities where
it is necessary to convey the fluid pressure from a distance through pipes. In the
latter case, instead of having the reservoir for compressed air in immediate
connection with the engine, it may be at a distance therefrom at the locality where
the air compressing engine is situated, or the reservoir may be entirely dispensed
with, and the air compressed by the compressing engine be conveyed directly
therefrom through pipes to the motor engine.
Having thus described the nature of my Invention, and in what manner the
same is to be performed, I hereby declare that I make no general claim to the use
of compressed air or other elastic fluid under high pressure for working locomotive
or other motor engines, but I claim in respect of such engines when they are
worked as compound engines by compressed fluid supplied from a reservoir to act
in successive cylinders,―
First. Regulating the working power by means of expansion apparatus applied
to the first cylinder so as to suit the cut off to the varying pressure in the
reservoir, substantially as herein described.
Second. Combining with the supply valves of the first cylinder hand gear,

page_text: whereby these valves can be held open, so that fluid at full pressure from the
reservoir can be permitted to act in the second cylinder, substantially as and for
the purposes herein set forth.
Third. The use in the supply passage to the first cylinder of double spring valves,
the one being free to seat itself independently of the other, as herein described
with reference to e¹ and e² in Fig. 3 of the accompanying Drawings.
Fourth. The combination of the lever G worked by an eccentric link, the levers
e with their rollers e6, the screwed rod ³ worked from the piston rod, and the
sliding adjustable blocks 6 constituting a variable cut-off apparatus for working
the supply valves of the small cylinder, as herein described.
Fifth. In combination with the cut-off apparatus referred to in the preceding
claim, the levers k¹ worked by hand for opening the supply valves of the small
cylinder, as herein described.
Sixth. In combination with the compound cylinders and their passages, casings
supplied with steam or hot fluid, as and for the purpose herein set forth."
In witness whereof, I, the said Frederick Edward Blackett, Beaumont, have
hereunto set my band and seal, this Fifth day of August, in the year of
our Lord One thousand eight hundred and eighty.
FRED. E. B. BEAUMONT. (L.S.)