Improvements in Compound Rotary Engines.
Year: 1897

page_text: Date of Application, 24th June, 1897
2000
PROVISIONAL SPECIFICATION,
Improvements in Compound Rotary Engines.
I, ROBERT HARRIS ISBELL, residing at Woodlawn, in the City of New York, in the
County of New York, and State of New York, United States of America, Machinist,
do hereby declare the nature of this invention to be as follows:
-
This invention relates to compound rotary engines, and the object thereof, is to
provide an improved device of this class in which the steam is used expansively.
In the practice of my invention, I provide a plurality of compound pistons each
of which is provided with an inner and an outer leaf which are pivoted in position in
such manner that the inner leaf of each piston rests on its edge against a stationary
hub that is approximately round, and the outer leaf of each piston travels against
the interior surface of the case or cylinder and these pistons are preferably three in
number, and are connected with a cylinder that is supported by a head and a shaft
from which the power is taken, and the hub and case are eccentric to the rotary
engine so that there are inner and outer steam chambers, the inner leaves of the
pistons being acted upon within the inner steam chamber by high pressure steam,
and the outer leaves of the pistons being acted upon in the outer chamber by the
steam as it expands; and the said steam finally passes off at the exhaust.
In my improved engine, the steam chambers are crescent-shaped and stand in
reverse directions and the engine consists essentially of a case provided with heads,
a stationary hub carried by one of said heads, a main shaft on this head, a cylinder
carried by the head and pistons at equal distance around the cylinder each having
a leaf, projecting inwardly, and a leaf projecting backwardly there being a port for
the high pressure steam in the reservoir, and through which the high pressure
steam passes to act upon the inner leaves of the pistons, a transverse port for the
high pressure steam to pass from the inner chamber to the outer chamber so that it
can act upon the outer leaves of the pistons, and an exhaust port from the outer
chamber; and in the operation of the engine, the full force of the expanding steam
is employed as the efficiency of the high pressure steam upon the inner leaves of
the piston diminishes, as the efficiency of the expanding pressure on the outer leaves
diminishes thus equalizing the power to rotate the main shaft, and either the high
pressure or the low pressure is also operated on each piston there being two pistons
acted upon by high pressure and one by low pressure or the reverse and hence the
power is always acting all around the shaft to equalize the strain.
Dated this 24th day of June 1897.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.

page_text: Improvements in Compound Rotary Engines.
I, ROBERT HARRIS ISBELL, residing at Woodlawn, in the City, County, and State
of New York, United States of America, Machinist, do hereby declare the nature
of this invention, and in what manner the same is to be performed, to be partic-
ularly described and ascertained in and by the following statement ; —
This invention relates to compound rotary engines and the object thereof is to
provide an improved engine of this class in which the steam is used expansively,
and with this object in view the pistons are compound and pivoted, the inner leaf
of each piston resting at its edge against a stationary hub that is approximately
round, and the outer leaf of the piston travels against the interior surface of the case,
and these pistons, preferably three in number, are connected with a cylinder that is
supported by a head and a shaft from which the power is taken and the hub and case
are eccentric to the rotary cylinder, so that there are inner and outer steam
chambers, the inner leaves of the pistons being acted upon within the inner steam
chamber by high pressure steam, and the outer leaves of the pistons being acted
upon in the outer chamber by the steam as it expands, and the same finally passes
off at the exhaust. In this engine the two steam chambers are crescent-shaped and
stand in reverse directions..
In the drawing, Fig. 1, is a cross section through the engine.
Fig. 2 is a section upon the line 2, 2, of Fig. 1.
Fig. 3 shows the interior surface of the case with the inlet steam port and the
transfer port.
Fig. 4 is a side view of the cylinder and outer pistons!
Fig. 5 is an end view of the shaft and cylinder.
Fig. 6 shows the inner side of the removable head, and,
Fig. 7 is a sectional illustration of the passage for the steam that first acts on the
outer piston:
The case of the engine is made with a stationary head A and a nearly cylindrical
or barrel portion B, and there is a removable head C that is bolted upon the case
at 5, and this removable head C, carries the hub D.
The main shaft E passes through the gland or stuffing box 6 and is supported in
a socket within the hub D, and there is advantageously an axial hole 7 for the
insertion of oil. Projecting from the main shaft E, and preferably made with the
same, is the head I to which is permanently connected the cylinder G, which is
made up of three parts permanently connected at one end to the head F and at the
other end to the ring 8, which ring 8 is supported by and travels in a circular
groove in the removable head C, and in consequence of the interior of the barrel B
being eccentric to the shaft E and approximately circular, there is a crescent-
shaped steam chamber 9 between the outer surface of the cylinder G and the
interior of the barrel or case B, the cylinder G setting closely against the interior
surface of the case B at one side and the hub D setting closely against the interior
surface of the cylinder G at the other side, and said hub being eccentric to the
cylinder G there is a crescent-shaped steam chamber 10 between the hub D and
the interior of the cylinder G; and it is now to be understood that the chamber 10
is for high pressure and the. chamber 9 for low pressure, the steam acting
expansively in the latter.
The pistons H are each advantageously made with an inner leaf 11 and an outer
leaf 12 and supported upon a pivot pin 13, and this pivot pin 13 passes through
the ring 8 into the head F, and these pistons set closely so as to be substantially
steam tight at the cylindrical or hinge portion of each piston, and the inner leaf 11
is smaller than the outer leaf 12, the chamber 9 being wider than the chamber 10

page_text: and it is to be understood that the distance between the outer edge of the leaf. 12
and the inner edge of the leaf 11 corresponds, or nearly so, to the distance between
the inner surface of the case B, and the outer surface of the hub D at the places
of contact, so that as the pistons travel around with the cylinder C their edges
remain in contact, or nearly so, with the surfaces named.
The outer surfaces of the cylinder G are recessed so as to allow the outer leaves 12
of the pistons H to pass into such recesses as the cylinder moves past the abut-
ment 14, or point of contact of the cylinder G with the interior of the case B, and
the inner surfaces of the cylinder G are also recessed to receive into them the inner
leaves 11 of the pistons as the cylinder passes the abutment 15 or point of contact
between the hub Dand the inner surface of the cylinder G.
The live steam under the proper pressure is admitted by the pipe I, and the
exhaust pipe K opens into the chamber 9 near one end of the said crescent shaped
chamber. The inlet steam pipe I opens into a port 16 which is in the stationary
head A and extends part way around the same as an arc of the circle, and there is
a similar shaped transfer port 17 in the head A and a branch 18 passing from such
transfer port and opening into the case B near the opposite end of the steam
chamber 9to the exhaust port K.
Through the head F are ports 19, there being one port for each of the three
pistons, and the ports are so positioned that as the cylinder G, head F and the
pistons revolve, high pressure steam is admitted through one of the ports 19 from
the steam port 16, and the high pressure steam acts between the abutment 15 and
one of the inner leaves 11 to carry the pistons and cylinders in the direction
indicated by the arrows, and the pressure continues active within the high pressure
chamber 10 until another piston is brought around into position for steam to be
admitted by the next port 19 to act upon such inner leaf 11 and continues the
movement, and the high pressure steam is cut off from the first named piston when
its port 19 reaches the end of the steam port 16, and the port 19 passes over the
inner surface 20 between the end of the steam port 16 and the commencement of
the transfer port 17, and as soon as such port 19 reaches the transfer port, the
high pressure steam in the inner chamber 10 passes through such transfer port 17.
and the branch 18 into the steam chamber 9 to act upon the outer leaf 12 of one of
the pistons which at this moment has been brought into proper position for the force
of the expending steam to be exerted upon the larger and outer leaf of the piston
to carry the same around to the exhaust pipe K and one piston is fully in operation
by the expanding steam when the piston that is in front of it reaches the exhaust
port so that there is no back pressure behind the piston, that is in full operation,
and so also the pressure acts in its full power upon the inner leaf of one piston
during the time that the high pressure steam is passing out from the proceeding
high pressure steam chamber through the transfer port, and by using three pistons,
each having two leaves, the circle is advantageously divided up into sections of 120,
and the outer leaf of one of the three pistons is at the point of greatest power at
the time the inner leaf of the next succeeding piston is going out of action and the
inner leaf of the third piston is coming into action, the inner leaves of the pistons
exerting their greatest force as the outer leaf of one piston is coming into action
and the outer leaf of the other piston is going out of action, so that the power
exerted all around the main shaft E to rotate the same, is uniform, or nearly so,
at all places.
In some instances I have used the engines with only the parts lierein before described,
but I find it advantageous to employ in addition ports for admitting steam to act
between the cylinder G and the outer leaf to press the edge of such outer leaf against
the interior of the case B and other ports to admit steam between the inner leaves 11
of the pistons and the interior surfaces of the cylinder G to press the edges of such
inner leaves into contact with the exterior surface of the hub D, and thereby prevent
the escape of steam at the respective places and prevent any hammering action that
might arise from looseness of the respective parts; and with this object in view, I
provide channels or ports a in the inner surfaces of the cylinder G at the bottom of

page_text: the recesses into which the inner leaves 11 of the pistons are received, and these
channels a open at their ends by lateral holes into the ports 19 so that steam will
pass through these ports 19 and channels a and act to press the inner leaves of the
pistons in succession so that they rest against the outer surface of the hub D before
the full force of the steam admitted through one of the ports 19 acts between the
inner leaf and the abutment.
I also provide a channel or port c in the bottom of each of the recesses receiving
the outer leaves of the piston, and these channels e open at their ends through the
head F, and it is important to admit live steam to act in these channels c and with
this object in view, I make a Ụ shaped port 21 in the stationary head A between
the end of the steam port 16 and the beginning of the transfer port 17 and the parts
are so proportioned that as soon as one port 19 passes the end of the steam port 16
so that the surface 20 closes the port 19 that the confined high pressure steam may
pass through that port 19 and through the U shaped port 21 and back through and
into the hole at the end of the channel c, and in so doing, the high pressure steam
will act to move the outer leaf of one piston H out of its recess so that its outer edge
bears against the inner surface of the case B before the port 19 reaches the
commencement of the transfer port 17 hence, as soon as this port 19 does reach the
commencement of the transfer port 17 the high pressure steam in the chamber 10
passes through such port 19 into the transfer port through the branch port 18 and
acts within the outer steam chamber 9 against the outer leaf of the pistor
which has, by the aforesaid movement been brought into position for the steam to
expand and exert its force against that piston in continuing the movement of the
cylinder G and its shaft.
The aforesaid operations being performed in succession, the full force of the
expanding steam is in operation as the efficiency of the high pressure steam upon
the inner leaves diminishes, and the efficiency of the high pressure steam upon the
inner leaves of the pistons increases as the efficiency of the expanding pressure
diminishes on the outer leaves, thus equalizing the power exerted to rotate the main
shaft, and either the high pressure or the low pressure is always operative on each
piston, there being two pistons acted upon by high pressure and one by low pressure,
or the reverse hence power is always acting all around the shaft to equalize the
strain and wear.
The engine is very simple, as there are but few parts to construct and they are
not liable to get out of order or to wear rapidly and the full benefit of expansion is
obtained.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I claim
is:-
1. A rotary engine comprising a case and its heads and a stationary hub carried
by one of the heads, a main shaft and its head, a cylinder carried by the head and
pistons at equal distances around the cylinder each having a leaf projecting inward
and a leaf projecting outward, there being a port for the high pressure steam ports
in the revolving head through which the high pressure steam passes to act upon the
inner leaves of the pistons, a transfer port for the high pressure steam to pass from
the inner chamber to the outer chamber, and act upon the outer leaves of the
pistons, and' an exhaust port from the outer chamber, substantially as set forth.
2. A rotary engine comprising an outer casing and its heads,
hub carried by
one of its heads, a shaft eccentric to the hub and a head upon such shaft, a cylinder
composed of sections and intermediate pistons having inner and outer leaves, a ring
for connecting the sections of the cylinder together and pivot pins passing through
the ring and head and upon which the pistons swing, a steam inlet port, and ports
through the head to which the cylinder is connected, a segmental transfer port and
branch for allowing high pressure steam from the inner chamber, to pass into the
outer chamber, and an exhaust pipe or port from the outer chamber, substantially
as set forth.

page_text: 3. In a rotary engine a main shaft and head, a cylinder supported by such head
and pivoted pistons in the cylinder having inner and outer leaves, the cylinder being
recessed for the reception of such leaves and ports or pipes for allowing steam to
pass into the recesses and beneath the respective leaves of the pistons for moving
such leaves. outward or inward to bring their edges into contact with the interior
surface of the case or the exterior surface of the hub, substantially as set forth.
4. A rotary engine comprising a case and its heads, a hub carried by one of the
heads, a main shaft, cylinder and pistons carried by such shaft, the pistons having
inner and outer leaves to act within the crescent-shaped steam spaces between the
cylinder and the case, and the cylinder and the hub respectively, the cylinder being
recessed for receiving the leaves of the pistons, steam ports for admitting pressure into
the recesses for swinging the respective pistons out of such recesses and a U-shaped
port in the head of the case for allowing such steam pressure to act in moving the
outer leaves of the pistons out of their recesses, substantially as set forth.
5. A rotary engine.comprising a stationary case and a stationary central hub,
an intermediate.cylinder placed eccentric and pistons passing through and pivoted
upon the said cylinder and having one leaf acted upon by pressure in the inuer
chamber, and the other leaf by pressure in the outer chamber, there being recesses
into which one leaf of each piston is swung while the other is in action, substantially
as set forth.
1
L 1000.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.