IMPROVEMENTS APPLICABLE TO STEAM AND OTHER MOTIVE-POWER ENGINES
Year: 1871

page_text: LETTERS PATENT to Robert Mudge Marchant, of Kirby Street;
Hatton Garden, in the County of Middlesex, Civil Engineer, for
the Invention of "IMPROVEMENTS APPLICABLE TO STEAM AND OTHER
MOTIVE-POWER ENGINES."
Scaled the 24th April 1871, and dated the 1st March 1871.
PROVISIONAL SPECIFICATION left by the said Robert Mudge Marchant
at the Office of the Commissioners of Patents, with his Petition,
on the 1st March 1871.
I, ROBERT MUDGE MARCHANT, of Kirby Street, Hatton Garden, in
the County of Middlesex, Civil Engineer, do hereby declare the nature
of the said Invention for "IMPROVEMENTS APPLICABLE TO STEAM AND OTHER
MOTIVE-POWER ENGINES," to be as follows:-
My Invention relates to improved means of regulating the supply
of steam, compressed air, or gas to the cylinder of an engine, or other
application to motive power of highly compressed gas, whereby any
determined cut off or regulation is necessarily effected in the delivery

page_text: of any specific charge at every stroke of the piston or revolution of
the machinery of the engine.
The Invention primarily consists in the application of highly com-
pressed or stored or manufactured steam, air, or gas in such manner
that any specific charge or proportion of the total capacity of the cylinder
can be delivered when the piston is at any determined position in the
cylinder during its commenced stroke from either end of the cylinder,
or when any other analogous medium for the conversion of the pressure
of the steam, air, or gas into motive power is at any determined
position.
By such application I am enabled to deliver the steam, air, or gas,
at any determined pressure, and to regulate the supply, working each
stroke or revolution of the engine in such manner that I can apply the
whole expansive power of the steam, air, or gas, comprised between any
attained pressure and the pressure of the surrounding atmosphere
without loss of any pressure by its delivery into any exhaust or into
the surrounding atmosphere itself at a pressure exceeding that of the
atmosphere.
By such application also I am enabled to construct an engine which
shall work with little noise and in which the whole power derived from
the expansion of the steam, air, or gas is applied to maintain the initial
momentum communicated by the charge under the full pressure at
which it communicates the motion to the engine.
The manner in which my Invention may be carried into effect is as
follows-Adjoining the cylinder of the engine is another cylinder which
I call the pressure chamber, this chamber is provided with three pistons
forming between them two spaces of any determined capacity pro-
portionate to that of the engine cylinder. These spaces are placed
alternately in communication with a pipe conveying the full attained
pressure at which the engine cylinder is to be supplied and they are
also placed alternately in communication with the corresponding ports
of the engine cylinder, being at the time of such communication cut
off from the supply pipe. It is evident that any determined charge
conveyed in this manner to the port of the cylinder can be made to
supply the full pressure at the commencement of the stroke and to
expand from such pressure to any determined exhaust.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Robert Mudge Marchant in the Great Seal Patent
Office on the 30th August 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
MUDGE MARCHANT, of Kirby Street, Hatton Garden, in the County of
Middlesex, Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of March, in the year of our
Lord One thousand eight hundred and seventy-one, in the thirty-fourth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto the said Robert Mudge Marchant, Her special licence that
I, the said Robert Mudge Marchant, my executors, administrators, and
assigns, or such others as I, the said Robert Mudge Marchant, my
executors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter 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 Invention for "Im-
PROVEMENTS APPLICABLE TO STEAM AND OTHER MOTIVE-POWER ENGINES," upon
the condition (amongst others) that I, the said Robert Mudge Marchant,
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, aud cause the same to be filed in the
Great Seal Patent Office within six calendar months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Robert Mudge Marchant, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof, reference being had to the accom-
panying Drawings, that is to say :—
My Invention relates to improved means of controlling and regulating
the supply to the cylinder of any engine of steam, compressed air, or
other gaseous body from which motive power is obtained; such means
having for their object more especially the use of very highly com-

page_text: reservoir. Between the valve cylinders G and G are two passages b¹
and b, and two passages P and P' are provided between the upper and
lower ports of the valve cylinder G* and the ends of the working
cylinder E. About the middle of the length of the valve cylinder G*
there is a passage X leading from the said cylinder to the atmosphere,
or with any receptacle into which it may be desired to exhaust. The
space included within the two cylinders G, G*, above the pistons A
and A' constitutes a measuring chamber for measuring charges of steam,
air, or other gaseous body to be delivered to the upper end of the
working cylinder E and the space included within the cylinders G, G*,
below the pistons A and A³ constitutes the measuring chamber for
measuring the charges to be delivered to the lower end of the working
cylinder. The pistons A, A, A1, A2, and the ports D, P, P', are so
arranged, and the said pistons have such motion communicated to them
by the connection of their rods a, a*, with eccentrics or other devices on
the main shaft or other part of the engine deriving motion from the
piston F as to operate in the following manner, the pistons A¹, A²,
always moving in an opposite direction to the pistons A, A:-The
pistons A, A, close the communication from the receiving port D before
either of the ports P, P¹, leading to the cylinder E is opened by its
respective pistons A', A². We will assume the parts to be in the
positions represented in the Drawings, and the pistons to be respectively
moving in the direction indicated by the arrows marked on the several
rods, a measured charge has been received through the port D into the
upper measuring chamber C', and all communication with the port D
is cut off by the upper piston A, which is now moving upwards, whilst
the pistons A', A², are moving downwards. The upper port P is on the
point of being uncovered by the piston A¹ for the delivery into the
upper part of the working cylinder E of the measured charge from the
chamber C' and the lower port P' has been uncovered by the piston A³,
and the lower end of the working cylinder is opened to the exhaust X.
The alternating strokes given to the rods a, a*, and their pistons reverses
the operation of the valves, and so causes a charge to be taken through
the port D into the lower measuring chamber C, and to be delivered
through the port P¹ into the lower end of the working cylinder, while
the upper end of the latter is opened to the exhaust X through the
port P. The travel of the pistons or valves A, A, A', A³, is so determined
by the eccentrics that the alternating rapid and slow movement duc

page_text: to the eccentrics occur at the points where such variation of speed is
necessary to perfect the operation.
The third cylinder II, shewn in section in Figure 3, is intended to
provide a means of increasing the charge contained in chambers O'
and C (Figure 2) for the application described by the addition to the
charge chamber C' of the space above the moveable piston A³ and to
the charge chamber C of the space below the opposite moveable
piston A³, these spaces, as shewn in Figure 3, being respectively lettered
also C' and C. These spaces are connected with and made to form
part of such chambers by means of passages which are dotted in their
position in Figure 3; these passages are opened or closed at will by the
moveable pistons A³, A³, and the chambers C¹ and C³, enlarged by
screwing these pistons together, and diminished by screwing them to an
increased distance apart by means of screw gear for the purpose, worked
from any handle.
The description and lettering already given refer equally to the other
construction or arrangement represented in Figures and 5, except
that according to the arrangement shewn in these Figures there is no
third cylinder H for the purpose of increasing the charge in the manner
described, but instead thereof screw gearing is provided in the cylinder G
for working these pistons A, A, at variable distances apart, so that the
additional charge required at any time is procurable by a later cut off
of the supply from the port D, which can by such means be made to
deliver its supply until any determined position of the piston to the
working cylinder has been reached; or by a different arrangement of
thic ports D, D, and b', 6ª, the steam or other motive fluid may be so
delivered from the ports D, D, as to keep up the full pressure represented
by the fluid on the piston valves A, A, and communicated by the
ports b¹, b, at positions nearer the centre above thic pistons A', Aº, in
the manuer already described.
It will be understood that by the within-described methods of carrying
out my Invention there is no communication between the main or
working cylinder of the engine and the generator or reservoir of tho
steam, air, or other gascous body from which the power is derived at
the time of the induction to the said cylinder, but that the measured :
charges are cut off from the generator or reservoir before being

page_text: delivered to the working cylinder, in which they operate only by their
expansive force.
And having now described the nature of my said Invention, and in
what manner the same is to be performed, I declare that I claim the
provision between the working cylinder of any steam or other motive-
power engine and the generator, reservoir, or other source of supply
of the steam or other gaseous body, of one or more measuring chambers
and valves, substantially such as are herein-before described, whereby
charges of the steam or other gaseous body are measured and cut off
from the generator, reservoir, or other source of supply before their
admission to the working cylinder, as herein-before explained.
In witness whereof, I, the said Robert Mudge Marchant, have
hereunto set my hand and seal, this Twenty-eighth day of
August One thousand eight hundred and seventy-one.