AN IMPROVED ROTARY ENGINE TO BE WORKED BY ATMOSPHERIC PRESSURE
Year: 1876

page_text: LETTERS PATENT to Jean Claude Blain, of Boulevard de Strasbourg, 123, Paris
(France), for the Invention of "AN IMPROVED ROTARY ENGINE TO BE WORKED
BY ATMOSPHERIC PRESSURE."
ealed the 29th December 1876, and dated the 25th July 1870.
PROVISIONAL SPECIFICATION left by the said Jean Claude Blain at the
Office of the Commissioners of Patents on the 25th July 1876.
Jean Claude BLAIN, of Boulevard de Strasbourg, 123, Paris (France).
PROVED ROTARY ENGINE TO BE WORKED BY ATMOSPHERIC PRESSURE."
"AN IM-
'
My Invention relates to an engine in which by employing steam only for the
purpose of producing a vacuum by its condensation, and using the pressure of the
atmosphere to effect the movement of the rotary shaft, great economy of fuel is
secured.
The engine consists of three principal organs arranged on the main shaft, a piston
cylinder, a main or great cylinder, and a lover of special construction, besides which
there are a condenser, an air pump, a fly wheel, and governor, all of ordinary
construction.
The great cylinder of ovoid form is fixed; it is closed at the top and open below.
Through apertures in its cover it receives steam from the boiler, which gives reci-
procating movement to the piston cylinder, which is of the same shape as the great
cylinder, but smaller, as it works within it. The piston cylinder is closed at the
one end, and at the other end is fitted with a piston which enters the great cylinder,
and has certain openings whereby steam from the great cylinder can pass into the
piston cylinder and return.
The lever consists of four wheels placed side by side on the shaft, the two middle
wheels being fixed thereon, and having ratchet teeth of opposite directions, the one
being employed to turn the shaft in the one direction, and the other to turn it in-
the opposite direction. Each of them is worked by a system of nine pawls,
mounted respectively on the two outer wheels, which are of larger diameter than
the middle wheels. On each of the outer wheels is mounted a ring connected by
wires to the pawls, so that they can at pleasure be thrown into or out of gear with
the ratchet wheels, and each of the said outer wheels is secured to the base of the

page_text: piston cylinder by a rigid piece of metal, the two pieces bolted together forming the
main arm of the lever.
On the cover of the great cylinder is a small closed cylinder forming a steam
chest, which communicates with the boiler by a pipe provided with a cock or valve,
and with the groat cylinder by a port governed by a rotating slide. The great
cylinder has also another communication with the boiler by a pipe provided with a
valve that can be opened by hand, but which is also opened by means of a tappet
adjusted by a screw on the piston cylinder, so that when the latter approaches the
end of its stroke its tappet acts through a system of levers on the said valve.
For marine engines I employ two sets of apparatus such as I have described, the
one being a master engine governing the movement of the other or auxiliary engine
by means of a tappet fixed on the master engine, which opens the condenser pipe of
the auxiliary engine. The cylinders of the auxiliary engine are shorter than those
of the master engine, because they act only during the time that the latter stops.
The steam which works the auxiliary engine comes from a reservoir surrounding
the upper part of the boiler, which reservoir is supplied with steam that has dono
work in the great cylinder.
For stationary engines a single set of the apparatus suffices, and as reversing is
not required, the duplication of the ratchet wheels is dispensed with.
The action of the engine is as follows:-Steam from the boiler being admitted
into the great cylinder forces out the piston cylinder, a portion of it entering the
same. When the piston cylinder approaches the end of its out stroke a tappet on
one of the outer wheels by means of levers opens a cock leading to the condenser,
whereupon the atmospheric pressure causes the piston cylinder to make its back or
in stroke, in which movement it by means of the pawls and ratchet wheel gives
motion to the shaft. As the piston cylinder approaches the end of its in stroke a
spring fixed on the cover of the great cylinder opens valves upon the piston passages,
so that the steam contained in the piston cylinder returns into the great cylinder,
and at the same time the tappet on the piston cylinder opens the steam valves,
whereby steam from the boiler and also from the steam chest, as well as that from
the piston cylinders, enters the great cylinder, and the piston cylinder being thus
subjected to the pressure of steam from three different sources, is caused to make its
out stroke, whereupon the action is repeated as above described.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Jean Claudo Blain in the Great Seal Patent Office on the 10th
January 1877.
JEAN CLAUDE BLAIN, of Boulevard de Strasbourg, 123, Paris (France). "AN IM-
PROVED ROTARY ENGINE TO BE WORKED BY ATMOSPHERIC PRESSURE."
My Invention relates to an engine in which by employing steam only for the
purpose of producing a vacuum by its condensation, and using the pressure of the
atmosphere to effect the movement of the rotary shaft, great economy of fuel is
secured, and the construction which I adopt for this purpose enables me to dispense
with piston rod, connecting rod, and crank, and thus to avoid the losses resulting
froin the use of those parts.
I will describe my improved engine, referring to the accompanying Sheets of
Drawings, and to the figures and letters marked thereon.
In Sheet I. Fig. 1 represents a side view, and Fig. 2 a plan of the engine.
In Sheet II. Fig. 1 represcuts a longitudinal section, and Fig. 2 a transverse
section on the vertical line of the shaft.
The other Figures relate to details of construction herein-after referred to.
The engine consists of a cylinder A of ovoid section, and curved to a circular are

page_text: struck from the centre of the shaft O. In this cylinder, which is open at the
bottom, works a piston B of corresponding section and curvature, and preferably
hollowed out, as shewn, for lightness. This piston has certain clearance between it
and the interior of the cylinder A, but is provided with packing a of any known
construction, such as spring rings, at its upper end. The other end of the piston is
connected by arms C to two wheels D, D₁, which can revolve freely on the shaft O.
Between those wheels is a ratchet wheel E fixed on the shaft, and 9 pawls b are
mounted on spindles c between the wheels D, D', these pawls being pressed by
springs & into gear with the teeth of E. When the piston B is pressed outwards by
steam admitted at the upper end of the cylinder A, the loose wheels D, D, are
turned partly round the pawls, slipping over the ratchet teeth, but when the piston
has completed its out stroke, as shewn in Fig. 1, Sheet I., and a vacuum has been
formed behind it by the condensation of the steam, the atmospheric pressure forces
the piston inwards, and the pawls engaging with the ratchet teeth turn the
ratchet wheel and shaft. A fly wheel, not shewn in the Drawings, continues the
movement of the shaft.
For the admission and emission of the steam there is a duplicate set of valve gear,
the one set being similar to the other. The gear for admission is shown in Fig. 1,
Sheet I., and that for emission in Fig. 1, Sheet II.; both sets are shewn in plan,
in Fig. 2, Sheet I. On the top of the cylinder A are three pipes T for admitting
steam from the boiler T₁, for the exhausting to the condenser, and a small pipe t
communicating with T for starting. In the pipe T is a valve v worked by a lever e,
connected at its one end by a rod f to a lever g mounted on an axis o, and at its
other ond connected by a link h to a spring i, provided with an auxiliary spring j
to increase its power when it is closed. Under the lever g is mounted a lever k,
connected by a link to a cranked lever m, the tail of which engages with a notch
at p in the end of the lever e, as shown in Fig. 1, Sheet I., which represents the
condition of the gear when the admission valve v is closed, the dotted lines
representing its condition when the valve is open. Two tappets F and G fixed on
the wheel D operate this gear. When the piston makes its out stroke the tappet F
acts on the tail of y so as to turn the valve v to the closed position, in which it is
retained by the catch at p of the lever m moved by a spring n. On the return
stroke of the piston the tappet G striking the end of the lever releases the catch
at p, whereupon the springs i, j, cause the valve v to be turned to its open position.
The exhaust valve gear shewn in Fig. 1, Sheet II., is of similar construction, the
corresponding parts being marked by the same letters distinguished by a dash. In
this case the tail of the lever g¹ is turned upwards, and is acted on by the tappet F¹,
and the catch lever m¹ is acted on by the tappet G¹, and both these tappets are
fixed on the wheel D¹. The pipe t is provided with a cock q, which is connected by
rods, and bell crank to a lever 8; a tappet 8 is adjusted on the end of the
piston, so that as the latter approaches the end of its instroke the tappet striking
the lever s causes the cock in the pipe t to be opened, thereby admitting steam to
the cylinder, in case the admission valve gear should fail to act, and so preventing
the piston from striking the top of the cylinder.
In constructing the tappets F, F1, and for adjusting their position I prefer an
arrangement, such as is shewn in Figs. 3, 4, and 5, Sheet II., Fig. 3 being a
transverse, and Fig. 4, a longitudinal section of one of the tappets, and Fig. 5, an
end view. The tappet consists of a roller F mounted in a box H within a casing H¹,
which can slide between cheeks L fixed on the periphery of the wheel D. The
height of the box H and roller F is adjusted by a wedge key K, and its position on
the periphery of D is adjusted by a screw M working through a nut N mounted by
trunnions on fixed brackets P. The loose wheels D, D', instead of revolving on the
shaft O, are preferably mounted on bosses projecting from the side frames X, as
shewn in Fig. 2, Sheet II.
Referring to Fig. 1, Sheet II., it will be seen that there are 9 pawls b, and
that the ratchet wheel E has 24 teeth, cach occupying 15° of its circunference. The
pawl is half of the tangent 1-2, which touches the outer circle of the teeth at 4.

page_text: The inside curvature of the pawl and the curved slope of the ratchet tooth are
struck from the centre 6, and the outsido curvature of the pawl from the centre 7.
A thickness of leather u is put as a facing on the pawls b to diminish noise in
working. The position of the centre o is determined as will be seen on reference to
Fig. 1, Sheet I. From 8 with radius 0.8, is struck an arc cutting the circumference
of D at 9, and from 9, with the same radius is struck an arccutting the horizontal
line at 10, and from 10 with the same radius is struck an arc cutting the vertical
tangent from 11 at o.
The engine above described with certain modifications is applicable to steam
propulsion, the paddle wheels or propeller being fixed on the shaf O with suitable
fly wheels to equalise the motion.
An opening in the lower side of the cylinder A (see Fig. 1, Sheet II.) is fitted
with a valve S in a cavity, which communicates with a receptacle R on the boiler R¹,
as shewn in transverse section at Fig. 6, and in part longitudinal section at Fig. 7,
Sheet II. At each out stroke of the piston B the valve S opens to allow the passage
of steam from the cylinder A to the receptacle R, but on the opening of the
cylinder A to the exhaust the valve S closes. The steam passing from Q enters the
receptacle R by a pipe U, and flows from it by a pipe U¹ to work any other engine.
The heat of the boiler maintains the temperature of the steam in R, and there is a
certain supply of steam from the boiler to the receptacle by a pipo U fitted with a
valve arranged as shewn in Fig. 7, Sheet II., so that the pressure in R shall not
exceed a certain amount. The valve v2 is connected to a lever a, which is loaded
by an adjustable weight y, and acted on by a small piston z subject to the pressure
in R. When that pressure is sufficient to overcome the load y, the valve v is more
or less closed by the movement of the lever x.
Having thus described the nature of my Invention, and in what manner the same
is to be performed, I claim, the construction of steam motor engine, substantially as
herein described, wherein a piston working in a curved cylinder is connected to
loose wheels provided with pawls, which pass the teeth of a ratchet wheel when
the piston makes its outstroke, but which engaging with those teeth during the
instroke of the piston give rotary motion to the shaft of the ratchet wheel, the
motive power being thus derived exclusively from the atmospheric pressure on the
piston acting when the steam is condensed.
In witness whereof, I, the said Jean Claude Blain, have hereunto set my hand
and seal, this Sixth day of January, in the year of our Lord One thousand
eight hundred and seventy-seven,
Witness,
CH. ARMENGAUD,
Civil Engineer,
23, Boulevard de Strasbourg,
Paris.
J. C. BLAIN. (L.S.)