Improvements in High Speed Compound Engines.
Year: 1894

page_text: Date of Application, 19th June, 1894-Accepted, 21st July, 1894
COMPLETE SPECIFICATION.
Improvements in High Speed Compound Engines.
1, JOSIAH Dow, of No. 4571 Pulaski Avenue, Germantown, in the City of
Philadelphia, in the County of Philadelphia and State of Pennsylvania, United
States of America, Engineer, 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 :-
My invention relates to high speed vertical compound steam engines and has for
one of its objects to place the high pressure and low pressure cylinders close to each
other so that simple steam passages at opposite ends of the cylinders, directly
conduct the steam from the exhaust of the high pressure cylinder to the low
pressure cylinder, and thus the clearance between the cylinders and through their
valves is very small.
Another object of the invention is to control the admission of steam to the
low pressure cylinder by the valve of the high pressure cylinder which governs
the inlet to and outlet from the high pressure cylinder, the opening of the exhaust
from the high pressure cylinder constituting the opening of steam for the low
pressure cylinder.
Another object of my invention is to provide mechanism for working both sets of
valves, the high pressure and the low pressure, from one crank plate.
Another object of my invention is to provide reliable governor-controlled
mechanism for determining the point of cut off and equalising the motion of the
valves at both ends of the high pressure cylinder.
Another object of the invention is to so arrange the connection of the valve gear
with the engine shaft as to give the valves the same movements in both the up and
the down strokes.
Another object of the invention is to provide throughout the engine a perfect
balance by counter-balancing all parts by other parts or by suitable counter-
poises.
The accompanying drawings illustrate my invention.
Fig. 1 shows, in dotted lines, an elevation of the frame and cylinders of the
engine, while in full lines are shown the valve gear, and the balanced mechanism for
operating the valves from the engine shaft. and for controlling the point of cut off
by the action of a governor.
Fig. 2, is a similar elevation at a right angle to the view shewn in Fig. 1.
Fig. 3, is an enlarged vertical section, on the line 3-3 of Fig. 4, through the
cylinders, steam and exhaust chambers, valves and passages, with the pistons and
piston rods in elevation.
Fig. 4, is a horizontal section on the line 4-4 of Fig. 3.
Fig. 5, is a section on the line 5-5 of Fig. 3, with the pistons removed.
Fig. 6, is a vertical transverse section on the line 6-6 of Fig. 5.
Fig. 7, is a view of one of the valves of the high pressure cylinder.
Fig. 8, is a view of one of the valves of the low pressure cylinder.
Fig. 9, is an enlarged perspective of the governor controlled mechanism for
equalising the action of the high pressure valves and determining the point of
cut off.
Figs. 10 and 11, are detail views of parts of the cut off mechanism.
1, designates the high pressure cylinder and 2 the low pressure cylinder. These
cylinders, as shewn, are placed vertically and in such relation to each other that a
simple steam passage 3, only the width of the cylinder ports, serves to conduct the
steam from the exhaust of the high pressure cylinder to the induction of the low

page_text: pressure cylinder, the admission of steam to the low pressure cylinder being
controlled by the exhaust valve of the high pressure cylinder.
4, is the initial steam chamber 5 is a closed air space which may be filled with
non-conducting material, is the exhaust chamber from the low pressure
cylinder 2 and 7 is another air space which may be filled with non-conducting
material. The cylinders 1 and 2 may as shewn be surrounded by a jacket & filled
with non-conducting material.
On the side of the steam clumber 4 is a steam inlet. 9 from the steam pipe 10.
At the ends of the steam chamber 4, are transversely arranged cylindrical valve
seats 4 each of which communicates by a port. II with the high pressure cylinder
and on the other side with the passage 3 lending to the corresponding valve of the
low pressure cylinder.
In each seat 4 is fitted a cylindrical oscillatory balanced hollow valve 12
which has steam admitted into its interior by openings 13 at its ends, as shown in
Figs. 4 and 7, from steam chambers 14 communicating with the steam chamber 4
by passages 1, Figure 6. The steam chambers 14 have a steam tight separation
from the valve seats 4 by means of packing rings 16, Fig. 4.
Each valve 12 has on one side, uarrow ports 17, by which steam can pass
from the interior of the valve into the high pressure cylinder 1 when the ports 17
coincide with the port. 11.
In the opposite side of each valve 12 is a packed balance port 18, Fig. 3,
and between the ports 17 and 18 is an exterior cut away or depressed portion
or pocket 19 to form an exhaust passage so that when the valve is moved so
as to present one side of the pocket 19 to the cylinder port 11 and the other
side to the passage 3, n direct channel is afforded through which the exhaust
steam from the high pressure cylinder passes to the valve of the low pressure
cylinder. Steam is not allowed to pass around the valve 12 and no steam
actually passes ont of the valve through the balance port. As the outside of
the valve is not subject to the pressure of steam, the excess of pressure at the
balance port 18 over that at the port 17, through which steam passes to the
cylinder, is only sufficient to hold the valve closely upon its sent at both steam and
exhaust passages and thus to render the valve as nearly perfectly balanced as may
be consistent with a firm seat.
The opposite ends of the low pressure cylinder 2 are provided with ports 20 that
communicate with cylindrical valve seats 6 in each of which is placed a solid
cylindrical two-way valve 21 having its exterior cut away longitudinally on one
side to form a passage 22, similar to the known Corliss exhaust valve. The valve
sents 6" communicato with the connecting passages 3 between the two cylinders and
also by exhaust ports 23 with the exhaust chamber 6 from which there is an
exhaust outlet 24 at one side. The passage 22 of each valve 21 presents itself
alternately to the passage 3 and then to the passage 23.
The low pressure piston 26 moves upwards exactly as the high pressure piston 25
moves downwards, they being balanced in stroke one against the other both in
movement and weight, the two cranks, pistons and roats being always in exactly
opposite positions. When the low pressure piston, in moving upwards, reaches the
point for cushioning and just before compression begins, the upper valve 21 closes
the exhaust passage 23. As this valve does not for another portion of the stroke
open to the passage 3, that passage, in the reverse motion of the valve, had been
closed during the downward stroke during the same time before exhaust took place
and consequently the passage 3 contains steam at higher pressure than that of the
low pressure exhaust, and, therefore, as the low pressure piston 26 moves upward
against compression it reaches, or about reaches, the pressure in the connecting
passage at the time when the valve 21 opens to it. Then the compression
continues in the low pressure cylinder 2 until the period for exhaust lead from the
high pressure cylinder which is thus added to the compression at the end of the
stroke in the low pressure cylinder. This gives three stages to the compression in
the low pressure cylinder and ensures a perfect balance of the steam between the

page_text: two cylinders, at the beginning of each stroke. These three stages are, first, the
closing of the exhaust port from the low pressure cylinder, second, the opening of
the low pressure cylinder port to the connecting passage 3, and third, the opening
of the exhaust from the high pressure cylinder I which becomes really the steam
opening for the low pressure cylinder 2, and determines the lead of steam for that
cylinder.
The length of the low pressure cylinder port 20 and the passage 22 of the
valve 21, is greater that the corresponding ports of the high pressure cylinder,
the low pressure cylinder being of greater diameter. Thus the commecting
passage 3 tapers from the valve seat 4 to the valve seat 6° and affords a very free
outlet for steam from the high pressure cylinder to the low pressure cylinder.
The close and compact arrangement of the cylinders, chambers, and valves and
the simple and direct connecting passages 3 between the two cylinders, the high
pressure exhaust lead controlling the low pressure steam lead, are important
features of the present invention contributing to greatly reduced clearance between
the cylinders and through the valves, which is a very valuable feature in a
compound engine.
Both sets of valves 12 and 21 are worked from one main crank plate 27. The
valve gear 28 and connections 29 for the high pressure valves 12, and also the
grooved or slotted cut off plates 30 and their connections 31 with a quadrant or
auxiliary crank plate 32, movable upon the same axis with the main crank plate,
but independent of it, may all be of any suitable or well known form and
arrangement. The main crank plate 27 is connected by rods 33 to arms 34 fixed
on the spindles of the low pressure valves 21.
The main crank plate 27 receives its motion through a rod 35 from an arm 36
on a rock-shaft 37, another arm 38 on which has a ball and socket joint to a rod 39
connected to a counter-balanced rocker arm 40 worked by a rod 41 from an
eccentric 42 on the engine shaft. The arm 40 is pivotted on the engine frame
at 43, on a bracket 43 The rod 39 is connected with one end of the arm 40 the
other end of which has a counter-balance 44 which may be a hollow ball or
cavity filled with lead or the like. The rod 41 from the eccentric 42 is connected
to the arm 40 at a point below the straight line connecting the centres of the
fulcrum 43 and of the end of the rod 39, this point being chosen so as to bring the
movement of the valve gearing into the same time for reaching each degree of its
advance in either direction, or going from the centre in either way of movement,
making the movements of the valves the same in both the up and down strokes.
The "cut off" at the high pressure valves 12 is effected through the quadrant
or auxiliary crank plate 32 which is movable upon the same axis as the main
crank plate but is entirely independent thereof. This auxiliary crank plate 32 is
connected by a rod 45 with a ball and socket joint to an arm 46 on a rock shaft 47
which has an arm 48, Figs. 9 and 10, on the outer side of which is a longitudinal
groove 49 receiving a pin or block 50 carried by a cut off, rocker arm 51 that is
pivotted at 52, about the middle of its length, to the engine frame. To the other
end of the lever 51 is jointed one end of a rod 53 the other end of which is forked
to receive a slide block 54 which is jointed to it and is loosely engaged in a
segmental slotted link 55 one end of which is pivotted by a pin 56, to the
unweighted end of the main rocker arm 40, as shewn in Fig. 2. To the other end of
the slotted link 55 is jointed a rod 57 connected to the cut off eccentric 58 on the
engine shaft.
As in other engines of the Corliss type, the point of "cut off is determined by
a governor, as will now be described.
A pendulum lever 59 Figs. 1, and 9, is suspended at 60 from a bracket 61
immediately behind the end of the rocker arm 51 to which is attached the rod 53.
The lower end of the pendulum 59 has a longitudinal slot 62, in which plays up
and down a subsidiary slide block 63 mounted on a pin 6-4 which passes through
the slide block 54. For the purpose of shifting the link slide block 54 to and
from the fulcrum 56 to vary the point of cut off, the pendulum 59 is moved into

page_text: In the face of the
plate 65 spiral cam groove 67 engages a pin or roller 68 on the pendulum 59; on
the rear of the plate 65 is a pinien 69 gearing with a reciprocating rack 70 by
which the cam plate 65 and pendulum 59 are actuated from any suitable governor.
The shorter end of the cam plate 65 may be counter-balanced at 71 as shewn in
Figs. 9 and 11. By suspending and arranging the pendulum 59 in the manner
described, it is capable of moving always in line with the rod 53 connecting the
lever 51 with the link slide block 54 by the position of which in the slotted link 55
is determined the point of cut off for the valves of the high pressure cylinder.
The plate 65 with its cam groove 67 is rocked in one direction or the other by the
rack 70, actuated from the governor, and the pendulum 59 is thus moved one way
or the other, carrying with it the link block 54 to a position for later or earlier
ent off.
As the pin 68 in the cam groove 67 is in the radial line with the centre of
the hearing of the plate 65, the reaction has no appreciable tendency to affect the
governor.
proper position by a cum plate 65, pivotted on a bracket 66.
Kear
72
The governor may be driven from the engine shaft. through the bevel
and upright shaft 73, Fig. 2, but, as the particular arrangement of the governor
forms no part
of my invention, it does not require illustration.
The balancing, throughout the engine, is by part against part where practicable
and elsewhere by counter-balances. This balance of the several parts includes
everything, the pistons, rods and cranks, the valve gear and crank plate connections,
ent of and the arrangements
the rocker arms, the governing mechanism for the
for the distribution of steam.
Having now particularly described and ascertained the nature of this inven
tion and in what manner the same is to be performed, I declare that what I
claim is
1. In a compound engine, the combination of a high pressure cylinder and a low
pressure cylinder placed close to each other with intermediate steam and exhaust,
and direct steam connecting passages, tapering from the ports of the high pressure
cylinder to the ports of the low pressure cylinder, and valves arranged between the
cylinders each controlling both the induction and the eduction of its cylinder and
the valves of the high pressure cylinder controlling also the lead of steam to the
low pressure cylinder, substantially as described.
2. In a compound engine Euch as is above referred to, the combination of the
cylindrical oscillatory valves, a single main crank plate and the valve gear and
crank plate connections, a counter-balanced main rocker arma actuated from an
eccentric on the engine shaft, a rock shaft having arms, one connected to the main
rocker arm and the other to the main crank plate, substantially as described.
3. The combination with the oscillatory valves, the main crank plate and the
valve gear and connections, of a counter-balanced main rocker arm actunted from
an eccentric on the engine shaft and connected with the main crank plate, a slotted
link carried by the main rocker arm and actuated from the cut off eccentric, a
block sliding in the link and connected to the cut off mechanism, a pendulum with
vertical slot and a block sliding thereon; a cam plate having its groove engaged
with a pin on the pendulum, and a rack and pinion for actuating the cam plate
from a governor, so as to vary the position of the link slide block, and deterinine
the point of cut off, substantially as described.
ABEL & IMRAY,
Agents for the Applicant.