IM- PROVEMENTS IN ROTARY ENGINES AND OTHER ROTARY APPARATUS
Year: 1879

page_text: LETTERS PATENT to John Clayton Mewburn, of 169, Fleet Street, in the City
of London, Patent Agent and Consulting Engineer, for the Invention of "IM-
PROVEMENTS IN ROTARY ENGINES AND OTHER ROTARY APPARATUS." A. com-
munication from abroad by François Pernot, of Gray, France.
Sealed the 25th November 1879, and dated the 16th June 1879.
PROVISIONAL SPECIFICATION left by the said John Clayton Mewburn at
the Office of the Commissioners of Patents on the 16th June 1879.
"
JOHN CLAYTON MEWBURN, of 169, Fleet Street, in the City of London, Patent
Agent and Consulting Engineer. IMPROVEMENTS IN ROTARY ENGINES AND OTHER
ROTARY APPARATUS." [A communication from abroad by François Pernot, of Gray,
France.]
This Invention has reference to rotary engines worked by steam, gas, or other
fluid; to rotary pumps and other rotary apparatus, such as fans and blowing
apparatus, and its object is to construct an apparatus which while possessing the
advantages of existing rotary apparatus shall offer further advantages with regard
to regularity and ease in working.
The apparatus consists essentially of a cylinder whose section is of a suitable
curve, elliptical by preference, in which an eccentrated nave turns. Through this
nave passes from side to side a sliding plate of constant length, and whose ends
always touch the inner periphery of the cylinder; the contact is made hermetic by
means of movable segments connected by knuckle joints. The continuous rotation
of the nave causes the sliding of the movable plate in the said nave without springs .
or other similar devices. The engine works by expansion, which may be made
variable by hand or by a governor.
Having explained the principle on which the Invention is based, I will proceed
to describe a rotary steam engine constructed in accordance therewith. The engine
is composed of a cylinder, by preference of oval or elliptical form, perfectly regular
and symmetrical. This form is adopted so that a sliding plate which revolves
passing constantly a point which is eccentrated in relation to the cylinder may
touch the inner periphery of the said cylinder. The said point is the axis of
rotation of the piston of the engine. The piston is composed of the nave through

page_text: which the sliding plate passes; this plate slides easily in the nave, and a hermetic
joint is made between them by means of metallic or other packing. Each of the
ends of the rotating sliding plate has a movable segment jointed so as to pivot on
the plate, and adopt the curved contour of the inner periphery of the cylinder. At
the upper part a metallic packing makes a hermetic joint along the line where the
nave touches the cylinder. A hermetic joint is also made between the rotary
piston and the ends of the cylinder by means of packing fitted in grooves formed
in the nave and sliding plate. The steam is admitted at one end of the cylinder by
a port communicating by a channel with the steam chest; the admission is
regulated by a rotary valve formed with two orifices, which allow the steam to
pass when they are opposite the said channel. The rotary valve turns with the
nave. The steam after having done its work exhausts through a port in the side
of the cylinder. The period during which the steam is admitted may be say a third
of the stroke, that is to say, a third of the half revolution, because each of the
parts of the sliding plate acts as a piston, and during one entire revolution there
are two periods of admission and of exhaust. The length of the orifices in the
rotary valve determines the duration of the admission. In order to produce a
variable expansion, a second valve or disc may be fitted against the first valve,
having orifices corresponding with those in the first valve; the second valve is
carried by a rod which passes out of the steam chest through a stuffing box. This
rod allows of shifting the second valve as required, either by hand or by the
governor, so that the orifices of the first valve are covered sooner or later, thus the
adinission of steam and consequently the expansion are regulated.
The engine is provided with a grease cock, and with purge cocks.
An elliptical form of the cylinder answers well the axis of rotation of the small
piston being eccentrated on the small axis; the dimensions of the cylinder will vary
according to the power of the engine. It is well to limit the amount of eccentricity
and to proportion it in a measure to the distance of the foci of the ellipse, it may
vary from a half to once the distance between the two foci.
Any other form than the elliptical may be given to the section of the cylinder
provided that the sliding plate, which is of constant length, will always touch by
both ends the inner periphery of the cylinder.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Clayton Mewburn in the Great Seal Patent Office on the
26th November 1879.
JOHN CLAYTON MEWBURN, of 169, Fleet Street, in the City of London, Patent
Agent and Consulting Engineer. "IMPROVEMENTS IN ROTARY ENGINES AND OTHER
ROTARY APPARATUS. "(A communication from abroad by François Pernot, of Gray,
France.)
The Invention has reference to rotary engines worked by steam, gas, or other
fluid; to rotary pumps and other rotary apparatus, such as fans and blowing
apparatus, and its object is to construct an apparatus which while possessing the
advantages of existing rotary apparatus shall offer further advantages with regard
to regularity and ease in working.
The apparatus consists essentially of a cylinder whose section is of a suitable
curve, elliptical by preference, in which an eccentrated nave turns. Through this
nave passes from side to side a sliding plate of constant length, and whose ends
always touch the inner periphery of the cylinder; the contact is made hermetic by
means of movable segments connected by knuckle joints. The continuous rotation
of the nave causes the sliding of the movable plate in the said nave without springs
or other similar devices. The engine works by expansion, which may be made
variable by hand or by a governor.
Having explained the principle on which the Invention is based, I will proceed
to describe with reference to the annexed Drawings a rotary steam engine con-
structed in accordance therewith; Figure 1 is a transverse section, and Figure 2
a longitudinal section of the engine. The engine is composed of a cylinder a, by
preference of oval or elliptical form, perfectly regular and symmetrical. This form
is adopted so that a sliding plate b which revolves passing constantly a point o,
which is eccentrated in relation to the cylinder may touch the inner periphery of
the said cylinder. The said point o is the axis of rotation of the piston of the
engine. The piston is composed of the naved through which the sliding plate b
passes; this plate slides easily in the nave, and a hermetic joint is made between
them by means of metallic or other packing e. Each of the ends of the rotating
sliding plate has a movable segment c jointed so as to pivot on the plate b, and
adopt the curved contour of the inner periphery of the cylinder. At the upper part
a metallic packing e¹ makes a hermetic joint along the line where the nave d
touches the cylinder a A hermetic joint is also made between the rotary piston
and the ends of the cylinder by means of packing e² fitted in grooves formed in the
nave d and sliding plate b. The steam supplied by a pipe at m to the steam chest
k is admitted at one end of the cylinder by a port y communicating by a channel
j with the steam chest; the admission is regulated by a rotary valve h (shown in
face view in Figure 4) formed with two orifices i, which allow the steam to pass
when they are opposite the said channel j. The rotary valve is carried on the end
of the shaft g and turns with the nave d, being acted on by the pin f. The steam
after having done its work exhausts through a port n in the side of the cylinder.
When the sliding plate b occupies the position seen in Figure 1, it is at the dead
point the exhaust and the admission of steam commence. The dotted lines show
the position the plate b occupies when the admission of steam ceases, the period of
expansion then begins, and the exhaust continues on the opposite side of the plate b.
The period during which the steam is admitted is represented in the Drawing as a
third of the stroke, that is to say, a third of the half revolution, because each of the
parts of the sliding plate b acts as a piston, and during one entire revolution there
are two periods of admission and of exhaust. The length of the orifice i in the
rotary valve h determines the duration of the admission. In order to produce a
variable expansion, a second valve or disc t (Figure 3) may be fitted against the

page_text: first valve h, having orifices corresponding with those in the first valve; the second
valve is carried by a rod 7 which passes out of the steam chest through a stuffing
box. This rod allows of shifting the second valve t as required either by hand or
by the governor, so that the orifices of the valve h are covered sooner or later ;
thus the admission of steam and consequently the expansion are regulated.
The engine is provided with a grease cock at o, and with purge cocks at p. It
is supported by a foundation or bed plates, and the shaft o which carries the fly
wheel is supported by a lubricated bearing 9.
An elliptical form of the cylinder answers well, the axis of rotation of the small
piston being eccentrated on the small axis; the dimensions of the cylinder will
vary according to the power of the engine. It is well to limit the amount of
eccentricity and to proportion it in a measure to the distance of the foci of the
ellipse; it may vary from a half to once the distance between the two foci.
Any other form than the elliptical may be given to the section of the cylinder,
provided that the sliding plate, which is of constant length, will always touch by
both ends the inner periphery of the cylinder.
And having now described the nature of the said Invention and in what manner
the same is to be performed, I declare that I claim as the "Improvements in
Rotary Engines and other Rotary Apparatus,"
First. Constructing such engines or apparatus with a cylinder of elliptical or
other suitable form, in which turns a nave touching the inner periphery of the
cylinder at one point, and traversed by a sliding plate working hermetically therein,
substantially as and for the purpose hereinbefore described and represented in the
annexed Drawings.
Second. The arrangement as herein before described and represented in the
annexed Drawings of the nave, the cylinder and the sliding plate fitted with
hermetic packings and having movable jointed segments.
Third. The arrangement of the rotary inlet valve as hereinbefore described and
represented in the annexed Drawings, and the combination therewith when
required of a second valve, as described, capable of regulation by hand or by the
governor for the purpose explained.
Fourth. Constructing rotary engines, as herein before described and represented
in the annexed Drawings.
In witness whereof, I, the said John Clayton Mewburn, have hereunto set my
hand and seal, this Twenty fifth day of November, One thousand eight
hundred and seventy nine.
J. C. MEWBURN. (L.S.)