IMPROVEMENTS IN LOCOMOTIVE ENGINES WORKED BY COM- PRESSED AIR, AND IN PRESSURE REGULATING APPARATUS FOR THE SAME, SUCH APPARATUS BEING ALSO APPLICABLE FOR REGULATING THE PRESSURE OF STEAM OR GASES EMPLOYED IN OTHER ENGINES
Year: 1875

page_text: LETTERS PATENT to Charles Denton Abel, of No. 20, Southampton
Buildings, Chancery Lane, in the County of Middlesex, for the
Invention of "IMPROVEMENTS IN LOCOMOTIVE ENGINES WORKED BY COM-
PRESSED AIR, AND IN PRESSURE REGULATING APPARATUS FOR THE SAME, SUCH
APPARATUS BEING ALSO APPLICABLE FOR REGULATING THE PRESSURE OF STEAM
OR GASES EMPLOYED IN OTHER ENGINES."-A communication from abroad
by Léon Ribourt, of Altorf, Canton Uri, Switzerland, Engineer.
Sealed the 2nd July 1875, and dated the 5th April 1875.
PROVISIONAL SPECIFICATION left by the said Charles Denton Abel
at the Office of the Commissioners of Patents, with his Petition,
on the 5th April 1875.
I, CHARLES DENTON ABEL, of No. 20, Southampton Buildings,
Chancery Lanc, in the County of Middlesex, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN LOCOMOTIVE ENGINES
WORKED BY COMPRESSED AIR, AND IN PRESSURE REGULATING APPARATUS FOR THE
SAME, SUCH APPARATUS BEING ALSO APPLICABLE FOR REGULATING THE PRESSURE OF
STEAM OR GASES EMPLOYED IN OTHER ENGINES," to be as follows.-
In working locomotives by the pressure of air or other clastic fluid

page_text: compressed into a reservoir the pressure diminishes as the reservoir
becomes emptied, and thus it is difficult to maintain constancy in the
working power.
This Invention relates to the construction of a locomotive to be
worked by compressed air, a pressure regulating apparatus being
employed so as to maintain the power constant, or nearly so, notwith-
standing the variation of pressure in the reservoir, and also to afford the
means of varying the power according to the exigencies of the road or
other circumstances The regulating apparatus is applicable also in
other cases where steam or other fluid under pressure is employed to
produce motive power.
The locomotive constructed according to this Invention consists of a
large and strong reservoir containing the compressed fluid mounted like
the boiler of an ordinary locomotive on framing and wheels, with springs
arranged in the ordinary manner. There are two or more cylinders
working cranks, with their slides, stopping, starting, reversing and
expansion gear, all of ordinary construction and arrangement. In the
communication between the reservoir and the cylinders are introduced
the regulating apparatus, which will be presently described, and a small
subsidiary reservoir, from which the cylinders are supplied with working :
fluid at a pressure less than that of the fluid in the main reservoir. The
object of the subsidiary reservoir is to give greater regularity to the
pressure of the working fluid, and to provide an clastic cushion to
absorb the sudden variations of pressure due to starting and stopping
the engines.
The regulating apparatus consists of a cylinder fitted with two pistons
connected together by a rod, which passes through the one open end of
the cylinder, and is pressed on by a spring that can be adjusted in its
force by means of a screw and hand wheel. The space in the cylinder
between the two pistons is always in communication with the main :
reservoir of compressed fluid by a pipe entering the side of the cylinder
near its open end. The farther end of the cylinder beyond the pistons
is closed to the atmosphere, but is always in communication with a pipe
leading to the subsidiary reservoir. Several holes pierced through the
side of the cylinder are also in communication with this pipe, which is
made with an expansion surrounding the regulating cylinder as an
annular cavity, into which these holes open Within the cylinder and

page_text: attached to or bearing against the farther piston is a cylindrical hollow
slide, fitted to work tightly in the cylinder, and having through it sido
holes, which in one position of the slide face the holes through the side
of the cylinder. The two pistons being equal are thus both equally
pressed on their inner faces by the fluid of the main reservoir. The
outer face of the farther piston is pressed by the fluid at the working
pressure in the subsidiary reservoir, while the outer face of the other
pitson is subject to atmospheric pressure, and the spring acts with
additional force in the same direction as the pressure of the atmosphere.
If then while the holes of the slide face those of the cylinder the
pressure in the subsidiary reservoir just balances that of the atmosphere,
together with the force of the spring; the pistons and slide remain at
rest, and fluid from the main reservoir passes by the holes in the slide
and cylinder into the subsidiary reservoir; but should the pressure in
the subsidiary reservoir be so far increased as to exceed that of the air
and
spring, then the pistons will be forced outwards, and the holes in the
slide being thus moved partly or entirely past those in the cylinder the
flow of fluid from the main reservoir will be partly or wholly stopped
until the working pressure again undergoes such reduction as will permit
the pistons and slide to be forced inwards by the spring. Thus while
the spring remains at constant force the working pressure in the sub-
sidiary reservoir remains constant or nearly so, and this pressure can bo
increased or diminished by varying the force of the spring, as may be
required, within a rango determined by the pressure in the main
reservoir, which can never be exceded.
It may be readily understood that in working a locomotive in this
manner it is desirable to employ cylinders of considerable area, working
with such moderate pressure as shall always be below the pressure in the
main reservoir when that has become reduced by the expansion and
partial discharge of its contents. At first starting, when the pressure in
the main reservoir is very high, the holes of the regulating slide will
uncover only minute portions of the corresponding holes in the regu-
lating cylinder, thus permitting the passage of only a very small volume
of the highly compressed fluid, but as the pressure in the main reservoir
diminishes the slide will gradually uncover more and more of the
passage holes, permitting the flow of a greater volume of fluid at the
lower pressure.
The voculating annaratus ahose decombed is obviously annbankla to

page_text: steam or fluids other than air for the purpose of obtaining a working
pressure constant, or nearly so, from a boiler or other receptacle in which
the pressure varies.
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 4th September 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
DENTON ABEL, of No. 20, Southampton Buildings, Chancery Lane, in
the County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fifth day of April, in the year
of our Lord One thousand eight hundred and seventy-five, in tho
thirty-eighth year of Her reign, did, for Herself, Her heirs-and suc-
cessors, give and grant unto me, the said Charles Denton Abel, Her
special license, that I, the said Charles Denton Abel, my executors, ad-
ministrators, and assigns, or such others as I, the said Charles Denton
Abol, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time, and at all times there-
after during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Inven-
Lion for "IMPROVEMENTS IN LOCOMOTIVE ENGINES WORKED BY COMPRESSED AIR,
AND IN PRESSURE REGULATING APPARATUS FOR THE SAME, SUCH APPARATUS BEING
ALSO APPLICABLE FOR REGULATING THE PRESSURE OF STEAM OR GASES EMPLOYED IN
OTHER ENGINES," a communication to me from abroad by Léon Ribourt,
of Altorf, Canton Uri, Switzerland, Engineer, upon the condition
(amongst others) that I, the said Charles Denton Abel,
my executors
or administrators, by an instrument in writing under my, or their, or
one of their hands and seals, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was
to be performed, and cause the same to be filed in the Great Scal
Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that I, the said Charles Denton Abel, do hereby
declare the nature of the said Invention

page_text: is to be performed, to be particularly described and ascertained in and
by the following statement thereof, reference being had to the accom-
panying Sheet of Drawings and to the figures and letters marked
thereon, that is to say:
In working locomotives by the pressure of air or other clastic fluid
compressed into a reservoir the pressure diminishes as the reservoir
becomes emptied, and thus it is difficult to maintain constancy in the
working power.
This Invention relates to the construction of a locomotive to be worked
by compressed air, a pressure regulating apparatus being employed so as
to maintain the power constant, or nearly so, notwithstanding tho
variation of pressure in the reservoir, and also to afford the means of
varying the power according to the exigencies of the road or other cir-
cumstances. The regulating apparatus is applicable also in other cases
where steam or other fluid under pressure is employed to produce motivo
power.
The locomotive constructed according to this Invention consists of a
large and strong reservoir containing the compressed fluid, mounted like
the boiler of an ordinary locomotive on framing and wheels, with springs
arranged in the ordinary manner. There are two or more cylinders
working cranks, with their slides, stopping, starting, reversing, and
expansion gear, all of ordinary construction and arrangement. In the
communication between the reservoir and the cylinders are introduced the
regulating apparatus, which will be presently described, and a small sub-
sidiary reservoir, from which the cylinders are supplied with working
fluid at a pressure less than that of the fluid in the main reservoir. The
object of the subsidiary reservoir is to give greater regularity to the
pressure of the working fluid, and to provide an elastic cushion to
absorb the sudden variations of pressure due to starting and stopping
the engines.
The regulating apparatus consists of a cylinder fitted with two pistons
connected together by a rod, which passes through the one open end of
the cylinder, and is pressed on by a spring that can be adjusted in its
force by means of a screw and hand wheel. The space in the cylinder
between the two pistons is always in communication with the main
reservoir of compressed fluid by a pipe entering the side of the cylinder
near its open end. The farther end of the cylinder beyond the pistons

page_text: is closed to the atmosphere, but is always in communication with a pipe
leading to the subsidiary reservoir. Several holes pierced through the
side of the cylinder are also in communication with this pipe, which is
made with an expansion surrounding the regulating cylinder as an
annular cavity, into which these holes open. Within the cylinder, and
attached to or bearing against the farther piston, is a cylindrical hollow
slide fitted to work tightly in the cylinder, and having through its side
holes, which in one position of the slide faces the holes through the side
of the cylinder. The two pistons being equal are thus both equally
pressed on their inner faces by the fluid of the main reservoir The
outer face of the farther piston is pressed by the fluid at the working
pressure in the subsidiary reservoir, while the outer face of the other
piston is subject to atmospheric pressure, and the spring acts with
additional force in the same direction as the pressure of the atmosphere.
If then while the holes of the slide face those of the cylinder the
pressure in the subsidiary reservou just-balances that of the atmosphere
together with the force of the spring; the pistons and slide remain at
rest, and fluid from the main reservoir passes by the holes in the slido
and cylinder into the subsidiary reservoir; but should the pressure in the
subsidiary reservoir be so far increased as to exceed that of the air and
spring then the pistons will be forced outwards, and the holes in the
slide being thus moved partly or entirely past those in the cylinder the
flow of fluid from the main reservoir will be partly or wholly stopped
until the working pressure again undergoes such reduction as will permit
the pistons and slide to be forced inwards by the spring. Thus while
the spring remains at constant force the working pressure in the sub-
sidiary reservoir remains constant, or nearly so, and this pressure can be
increased or diminished by varying the force of the spring, as may be
required, within a range determined by the pressure in the main
reservoir, which can never be exceeded.
It may be readily understood that in working a locomotve in this
manner it is desirable to employ cylinders of considerable area working
with such moderate pressure as shall always be below the pressure in the
main reservoir when that has become reduced by the oxpansion and
partial discharge of its contents. At first starting, when the pressure in
the main reservoir is very high, the holes of the regulating slide will
uncover only minute portions of the corresponding holes in the regu-
lating cylinder, thus permitting the passage of only a very small volume

page_text: The regulating apparatus abovo described is obviously applicable to
steam or fluids other than air for the purpose of obtaining a working
pressure constant, or nearly so, from a boiler or other receptacle in
which the pressure varies.
Fig 1 represents a side view, and Fig 2 an cnd view of a locomotivo
worked by compressed air or other clastic fluid.
R is the main reservoir of clastic fluid, and R² is the subsidiary
reservoir, from which the cylinders are supplied. The one reservoir R¹
communicates with the other R³ through a pipe, in the course of which
is situated the regulating apparatus R, a longitudinal section of which
is shown to a larger scale at Fig. 3. It consists of the cylinder A
enclosed in the casing C, which forms an annular cavity round the
cylinder. The interior of the cylinder communicates by the pipe B with
the main reservoir R, and the exterior cavity communicates by the
pipe D with the subsidiary reservoir R. The cylinder is fitted with a
hollowed piston E with packing II, the rod F of which piston has on
it a collar G with packing forming a second piston. N is the spring
compressed between the two discs K and L, the latter of which can bo
set forwards or backwards by the screw M, so as to vary as desired the
pressure of the spring N In the side of the cylinder A are bored
holes a, a, and corresponding holes e, e, are bored in the piston E. It
will be seen that the internal pressure between the two pistons E and G
acts equally on both, while those pistons are forced outwards by the
pressure of the fluid in the subsidiary reservoir acting on the surface
of II, and they are forced inwards by the atmospheric pressure acting on
the outer surface of G and by the spring N. When the pistons are in
the position shown in Fig. 3 there is free passage through some of the
holes a for fluid to pass from the main to the subsidiary reservoir, but
should the pressure of the fluid in the latter become too great, then the
piston E is forced forward in opposition to the spring N, closing or
partially closing the orifices a, and thus the regulation of the pressure

page_text: of the fluid acting in the cylinders of the engine is regulated as described
above.
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 locomotives worked by com-
pressed air or other fluid the combination of a main reservoir of
compressed fluid with a subsidiary reservoir and an intermediate
pressure regulating apparatus, constructed and arranged substantially
in the manner and for the purposes herein set forth.
In witness whereof, I, the said Charles Denton Abel, have here-
unto set my hand and scal, this Third day of September, in
the year of our Lord One thousand eight hundred and seventy-
five.