Improvements in Rotary Fluid Pressure Engines.
Year: 1898

page_text: Date of Application, 8th Feb., 1898-Accepted, 2nd Apr., 1898
Improvements in Rotary Fluid Pressure Engines.
I, WILLIAM BERGEN BROWN, of No. 221 North Charles Street, Baltimore City, in the
State of Maryland, United States of America, Optician, do hereby declare the nature of
this invention and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
This invention relates to rotary engines worked by steam or other elastic fluid and
has for its objects certain improvements in the construction, arrangement and
combination of the parts of a compound rotary steam engine of large size and adapted
for high pressures, as I shall describe referring to the annexed drawings.
Figure 1 is an elevation partly sectional of, a compound rotary steam engine
according to my invention.
Figure 2 is a vertical section on the line 2-2 of Figure 1, shewing the high
pressure cylinder in side elevation and the cut-off valve in vertical section.
Figure 3 is a vertical section on the line 3-3 of Figure 1, looking at the opposite
side of the high pressure cylinder.
Figure 4 is a vertical transverse section, on the line 4-4 of Figure 1, through the
high pressure cylinder, shewing the concentric rotary piston body with its two radial
blades and two sliding gates or abutments that reciprocate transversely.
Figure 5 is a partly sectional and partly broken detail view of the piston body and
a piston blade and its inclosed spring expanded packing plates or blocks.
Figure 6 is a perspective of a portion of the recessed periphery of the rotary
piston body.
Figure 7 is a perspective of a piston blade with packing blocks removed.
Figure 8 is a perspective of the rebated and laterally expansible packing blocks for
a piston blade.
Figure 9 is a plan partly sectional of the high pressure cylinder and its two
auxiliary reciprocating engines for operating two sliding gates or abutments in proper
relation to the required movements of two radial pistons or blades carried by the
rotary piston body.
Figure 10 is a section, on the line 10-10 of Figure 9, transversely through an
auxiliary engine and its valve chests.
Figure 11 is a perspective of the main valve of auxiliary engine.
In Figure 1 is represented a two-cylinder rotary compound engine with auxiliary
horizontal reciprocating engines for operating the sliding gates or abutments that act
with the rotating pistons. designates the high pressure cylinder and 2 the low
pressure cylinder.
Figures 2 and 3 represent opposite sides of the high pressure cylinder, and Figure 4
a vertical section through the said cylinder shewing its ports 3, 4, 5 and 6 for
admission and exhaust of steam or other working fluid for driving, preferably, two
radial piston blades 7 mounted in a rotary piston body 8 concentric with the
cylinder.
The cylinder ports 3, 4, 5 and 6 are arranged below and above the paths of two
horizontally sliding gates or abutments 9, Figures 1, 4, and 9, that are reciprocated
transversely in the plane of the engine shaft 10.

page_text: As shewn in Figures 4 and 6, the periphery of the rotary piston body 8 is provided
with recesses 11; at diametrically opposite points to receive the radial piston blades 7
which are of rectangular form, as shewn in Figures 4 and 7. Each piston blade 7 is
slotted as shewn for reception of laterally expansible packing blocks 12, Figures 4, 5,
8 and 9. These packing blocks 12 are rebated to have an overlapping and sliding
engagement with each other and have recesses 13, Figures 5 and 8, for reception of
springs, 14, to force them outwards laterally into close fluid-tight contact with the
sides of the cylinder in which the blades work. In the bottom of each recessed
blade 7 is placed a spring 15, Figures 4 and 5, to press the packing blocks 12
radially outwards into close fluid-tight contact with the periphery of the
cylinder.
The sides of the rotary piston body 8 are provided with annular grooves in which
are placed packing rings 16, Figures 4, 6 and 9, with springs 17 behind them. In
the sides of the cylinder, at or adjacent to the periphery of the rotary piston body,
there are annular recesses or grooves for packing rings 18, Figure 9, preferably
having elastic packing 19, followers 20 and springs 21 behind them. The packing
carried by the rotary piston body may be like that just described consisting of the
parts 18, 19, 20 and 21.
As shewn in Figures 4 and 9, each sliding gate or abutment 9 is longitudinally
grooved along the edge that meets the periphery of the rotary piston body, and has
in the groove a packing strip 22, with a spring 23 at its back. As shewn in Figure 4,
the periphery of the engine cylinder is preferably slotted for insertion of the gates
and to form guides 24 for each gate; plates 25, close the slots. The inner side of
each plate 25 is grooved to receive a substantially flat spring 26, which is secured at
one end to the plate and bears, for the greater part of its length, against the outer
edge of the sliding gate 9 to force it into close contact with the periphery of the
rotary piston body 8. In order to provide for a full closing stroke of each sliding
gate 9, without meeting the cylinder wall, there is a space 27, Figure 9, which is
practically a continuation of a housing 28, Figures 1 and 9, in which the sliding
gate 9 is reciprocated. In the body of the sliding gate 9 are longitudinal passages 29,
Figure 9, to lessen the momentum and inertia of the gate and permit a free passage
of fluid. As the piston blades 7 are thicker than the sliding gates 9, when these
gates are withdrawn, the passing piston blades, or their packing, cannot spring into
the gate guideways 24.,
Each sliding gate or abutment 9 is fixed to the rod 30 Figures 1 and 9, of the
piston 31 of an auxiliary horizontal and double acting reciprocating engine 32,
secured to the housing 28 in which the gate is reciprocated. In a rotary compound
engine having two cylinders, with two sliding gates to each, there are four of the
auxiliary gate operating engines 32, all of like construction.
Each auxiliary engine 32 has two inlet ports 33 connecting the ends of the
cylinder with the middle portion of a valve chest 34 which receives exhaust from the
cylinder through two exhaust ports 35 which enter the cylinder in such manner as to
provide for cushioning the piston 31 at the ends of its stroke. The valve chest 34
has a central inlet port 36. and exhaust ports 37 near its ends. The slide valve
consists of two piston heads 38 fixed on the valve rod 39 at a suitable distance apart
and having between them a cut off sleeve 40 loose on the valve rod which is pushed,
first in one direction and then in the other, by the heads 38. In one side of the cut-
off sleeve 40 there is a longitudinal groove 41, which is always presented toward the
valve chest inlet 36 being prevented from turning by a pin 42 on the valve rod
projecting into the groove 41. The cut off sleeve 40 has longitudinal passages 43, to
lessen the momentum of the sleeve and allow passage of fluid.
A link 44, Figure 9, connects the valve rod 39 with the lower end of an arm 45,
Figures 1 and 3, on a rock shaft 46 pivotted in bearings 47. On the rock shaft 46 is
a crank arm 48 with pin 49, Figure 9, engaged in a hole in the lower end of a
vertical slide 50, Figures 1 and 3, supported in a guide bracket 51. The guideway 51
is slotted, as shewn in Figures 1 and 3, for passage of a pin 52 connecting the
vertically movable slide 50 with a slotted link 53 which is connected, through

page_text: eccentric rods 54, with two eccentrics 55 carried by a pinion 56 which is mounted on
a stud 57 and driven by a wheel 58 fixed on the main shaft 10, of the engine. As
there are two radial piston blades 7 and two reciprocating gates 9 for each cylinder
the multiplying gear 58 and 56, cause operation of the valve mechanism of the
auxiliary engines 32 at each half revolution of the main engine shaft.
For reversing the valve mechanism of the auxiliary engines 32 a rock shaft 59,
Figures 1, 2 and 3 journalled in bearings at the base of the engine has at its ends
vertical arms 60 connected by links 61, to the slotted links 53, as shewn in Figure 3.
The rock shaft 59 is moved by a hand lever 62, Figures 1 and 3, which may have a
spring catch as shewn.
As means of operating the sliding gates 9, the double acting auxiliary engines 32
offer the advantages of cheapness in construction; economy in the use of steam or
working fluid; freedom from jar or concussion; and rapid, positive action. The
reciprocating pistons 31 and connected gates 9 travel with great rapidity, to suit a
high speed rotary engine. But owing to the arrangement of the ports of the
cylinders 32 and the positive cut-off effected by the sleeve 40, the consumption of
steam or working fluid is economised and the piston 31 is effectively cushioned
without jar or concussion. It is found, by experience, that the piston 31 cushions
with more force when the gate 9 is closing than when opening; for then there is no
pressure on the gate causing friction. In the opening stroke the gate 9 being
subjected to pressure starts under greater frictional resistance. In order to decrease
the driving force of the closing stroke, to avoid concussion and also economise working
fluid, the cut-off sleeve 40 is arranged to be operated as described by the heads 38 of
the slide valve.
When high pressures are employed, it is necessary either to increase the depth of
the cushion or to increase the cushioning resistance. For this purpose there is
provided a supplementary slide valve having piston heads 63, Figure 9, secured to a
valve rod 64, at a suitable distance apart, and having between them a cut-off sleeve 65
loose on the valve rod. This valve operates in a supplemental chest 66 communica-
ting with the cylinder through ports 67 Figure 9. The valve chest 66 has an inlet 68
for steam or working fluid preferably with a check valve 69. The cut-off sleeve 65
has a longitudinal groove 70, Figures 9 and 10, into which projects a pin 71 fixed on
the valve rod. In each valve head 63 there is a longitudinal passage 72 for fluid.
This supplementary cushioning valve is similar to the main slide valve except that
the cut-off sleeve 65 is longer than the cut-off sleeve 40, and that the valve heads 63
have longitudinal passages 72 and are somewhat shorter than the heads 38 of the
main valve. The rod 64, of the supplementary valve, has collars 73 and 74, at
suitable intervals, by which the supplementary valve is moved in both directions from
the gate 9 by means of a tappet 75 on the outer edge of the gate. On the valve
rod 64, at each side of the tappet 75, there are springs 76 to lessen the shock of
impact.
It is not necessary to have the supplementary valve 63-65 if the cushioning space
of the cylinder can, with convenience, be made sufficiently long. The chief advantage
of this supplementary valve is to permit of shorter cushioning spaces, as it increases
the cushioning resistance as the pressure on the piston 31 increases. The fluid
compressed in the cushioning spaces is not lost but is ready, like a spring, to give out
power as soon as the pressure on the opposite side of the piston is relieved. When
the piston 31 covers either exhaust port 35, the supplementary valve 63-65 admits
steam or fluid at the same pressure as that admitted by the main valve 38-40 for
propelling the piston, and so offers greater resistance to the piston and obviates shock
at the end of the stroke. This supplementary valve 63-65 is intended to be used
only when high pressures are employed.
Besides the advantages of simplicity and cheapness in construction of the auxiliary
engines 32, the arrangement and formation of the valves give large economy in the
use of steam or other working fluid; free exhaust; positive action of the valves; but
little friction; and effectual means for increasing the cushioning resistance as the
propelling force on the piston increases. As shewn by experiment under fifty pounds.

page_text: working pressure and with the engine making sixty revolutions per minute, the
closing of the sliding gates is practically instantaneous, after the piston blades have
passed. The object of employing two gates and two radial pistons with each rotary
piston body is to equalise the pressure on the piston body; and it also increases the
power as the acting pressure is twice that which would act on a single piston.
Referring to Figure 1, 77 is a main supply pipe for the steam or other working
fluid. It communicates with a chamber 78 in which is arranged a governor valve (not
shewn) controlled by a governor 79 driven by a pulley 80 driven by a belt from a
pulley 81 on the main engine shaft. This pulley 81, Figures 1 and 2, may be made
in two parallel halves, each a flanged disc fixed to one end of a divided main shaft 10
and coupled by bolts 82 after the two parts of the engine shaft have been axially shifted
to adjust the rotary pistons of the high pressure cylinder 1 and low pressure cylinder 2
in the required relation to each other.
Below the governor valve chamber 78 there is a cut-off valve chamber 83, Figures 1
and 2, enclosing a main cut-off valve 84 having a depending stem 85 the lower end of
which is connected, in the usual way, with the slotted link 86, Figure 2, connected
by links 87 to two eccentrics 88 on a pinion 89 driven from a wheel 90 on the main
engine shaft. A bar or rod 91, Figure 2, connects the slotted link 86 with a hand
lever 92 for shifting the said link, to vary the cut-off. This hand lever 92 is fulcrumed
As shewn in Figure 2, the cut-off valve 84 has longitudinal bores 94 for
passage of working fluid.
at 93.
The cut-off valve chamber 83 and governor valve chamber 78 are supported by a
bracket 95, Figure 1, on one side of the high pressure cylinder.
Referring to Figure 2, the opposite sides of the cut-off valve chamber 83 have
ports 96 to pipes 97 that connect with the vertical casings 98 of two main reversing
valves 99, Figures 1 and 2, each of which comprises a valve rod 100 with several,
preferably four, piston heads on it. The upper ends of the valve rods 100 are
connected by a two-armed lever 101, centrally fulcrumed at 102, and provided with
suitable spring catch as shewn. The reversing valve casings 98 communicate with
the high pressure cylinder 1 through the ports 3, 4, 5 and 6, Figure 4, herein before
mentioned. When the engine revolves in the one direction, the steam or working
fluid enters the high pressure cylinder from the one reversing valve through the
port 3, below one of the sliding gates 9; and from the other reversing valve through
the port 5, above the other sliding gate. The fluid admitted through the port 3, is
discharged through the port 4, Figure 4, to the other reversing valve; and, conversely,
the working fluid admitted at the port 5, escapes at the port 6. To drive the engine
in the opposite direction the reversing valves 99 are so set as to admit working fluid.
to the high pressure cylinder at the ports 4 and 6 and discharge at the ports 3 and 5.
The exhaust from the high pressure cylinder 1 is directed by the reversing valves 99,
through pipes 103, Figures 1 and 2, into the low pressure cylinder 2 which has blades
and gates similar to those of the high pressure cylinder.
The exhaust from the low pressure cylinder 2 passes, through pipes 104, Figures 1
and 2, into the upper and lower end portions, respectively, of the chambers 98 that
enclose the reversing valves. When the valves 99 are reversed, the pipes 104 lead to the
inlets of the low pressure cylinder 2 and the pipes 103 lead the exhaust from the low
pressure cylinder to the reversing valves.
The upper and lower ends of the reversing valve casings 98 have elbows 105 and
Ts 106 connected by pipes 107, as shewn in Figure 2 and communicate with the
exhaust pipe 108.
From the main supply pipe 77, Figure 1, there are branch pipes 109, to the inlet
ports 36 and 68 (Figure 9) of the valve chests on the auxiliary engines 32 which
have their exhaust ports 37 connected by pipes 110 to the exhaust pipe 108.
The main shaft of the engine may be extended a sufficient distance to provide for
carrying on its end a fly wheel 111, or any suitable wheels or pulleys, and may have a
bearing in a pedestal 112.
In the main steam supply pipe 77 there is preferably placed a hand valve 113,
Figure 1, between the governor valve casing 78 and the connection of the pipe 77

page_text: to the branch pipes 109 so that by this valve 113, working fluid can be shut off from
the rotary engine without affecting the operation of the auxiliary engines except as
they are controlled by their valves 38 (actuated from the main engine shaft. The
supply of working fluid to the branch pipes 109 may be cut off, when necessary, by
means of a valve (not shewn) near the boiler or other source of working fluid. As the
working pressure for the auxiliary engines is thus independent of that for the rotary
engine, and as the valves 38 of these engines are controlled from the main engine
shaft, a sudden loss of pressure in the rotary engine does not incur risk of collision
between the sliding gates and the rotary piston blades while these continue to revolve
by momentum.
In the inlet pipe to each supplementary valve chest 66 there is a hand valve 114,
Figure 1, to cut off supply of working fluid when increase of cushioning resistance
for the pistons of the auxiliary engines is deemed unnecessary.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what I
claim is :-
1. In combination with a cylinder, and a rotary piston body having piston blades
sliding gates suitably packed and caused to reciprocate parallel to the engine shaft,
by auxiliary double acting suitably cushioned engines having slide valves actuated
from the shaft of the rotary engine, substantially as described.
2. In each auxiliary double acting engine working the sliding gate, a valve chest
having a central supply port and end exhaust ports and communicating with the ends
of the auxiliary engine cylinder by inlet and outlet ports a slide valve comprising a
rod having two fixed piston heads and a loose cut-off sleeve between them, and
mechanism for actuating the slide valve of the auxiliary engine from the shaft of the
rotary engine, so as to drive the piston in both directions controlling the exhaust and
cushioning said piston at each end of its stroke, substantially as described.
3. In combination with each auxiliary double acting engine, a supplementary
valve chest and slide valve actuated by tappets intermittently from the sliding gate
and comprising a stem having on it fixed piston heads and a loose cut-off sleeve so as
to control cushioning resistance according to the working pressure, substantially as
described.
4. In combination with the auxiliary engines, a rock shaft having arms, linked to
the rods of the slide valves of the auxiliary engines, a crank arm on the rock shaft
worked by a vertically movable slide moved by a slotted link and eccentrics on a
pinion driven from the main engine shaft and lever mechanism for moving the slotted
link, substantially as described.
5. In combination with the high and low pressure cylinders, two reversing valves
communicating with the high pressure cylinder through ports above and below the
paths of the sliding gates, two sets of crossed pipes connecting the reversing valves
with the low pressure cylinder above and below the paths of the sliding gates therein,
and a main cut-off valve communicating with the two reversing valves and actuated
from the main shaft of the engine at each half revolution of said shaft, substantially
as described.
COLL J
2.
1000