Year: 1888

page_text: Date of Application, 18th Jan., 1888
Specification Accepted, 20th July, 1888
A communication from abroad by MARSHALL T. DAVIDSON, of Brooklyn, King's
County, in the State of New York, United States of America, Manufacturer.
I, PHILIP MIDDLETON JUSTICE of 55 and 56 Chancery Lane in the County of
Middlesex Fellow of the Institute of Patent Agents, 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 :-
The invention relates to that class of steam engines in which the exhaust steam
from a high pressure engine or cylinder is used expansively in another cylinder, and
the invention consists in providing the engine with three cylinders axially in line, and
in supporting and arranging said cylinders, and in connecting the valves and other-
wise constructing the engine so as to increase its efficiency, and facilitate its
construction and operation.
To clearly explain the nature of the invention reference is made to the accompanying
drawings in which :-
Fig. 1 is a sectional side elevation of a compound pumping engine embodying the
invention.
Fig. 1 is a section on the line a-b of Fig. 1.
Fig. 2 is a plan view, and
Fig. 3 is a sectional plan.
The bed A of the engine has a support B, for the central low pressure cylinder C
of the engine, and when the engine is a pumping engine the bed also supports the
pump cylinder (not shown), but when the latter is not employed the pillar blocks of
the engine crank shaft may be arranged upon the bed.
The rear head 1, of the cylinder C, is bolted in place as usual and to the said head
is secured a bracket 2, bolted at the outer end to the inner head of a high pressure
cylinder E, which is thus supported by and in line with the cylinder C, and
independently of the bed.
To the forward head 3 of the cylinder C, is secured another but smaller low pressure
cylinder F, the high pressure cylinder E, and the two low pressure cylinders being in

page_text: line axially and the central cylinder thus supporting both of the other cylinders. All
of the cylinders are of the same length.
The cylinder F is provided with a piston 4, and central piston rod 7, connected to
or carrying a cross head g, (Figs. 2 and 3) and to the latter are attached the two
parallel piston rods 8 8, of the piston 5, of the middle cylinder C, which extend 5
through packing boxes on that part of the head 3, which is outside the periphery of
the forward cylinder.
The piston 6 of the high pressure cylinder E, is connected by a rod 10 axially
arranged, with the piston 5 of the cylinder C, so that all the pistons move in unison
and have the same stroke.
The cylinders F, C, E, are provided respectively with valve chests 12, 13, 14, and
with suitable valves and ports, and the exhaust port of the high pressure cylinder E
is connected by a pipe 15, with the inlet port of the forward chest 12, and the
exhaust port of the latter is connected by a pipe 16, with the inlet port of the central
chest 13, and the valves are so controlled that the steam after doing its work in the
cylinder E is exhausted into the forward cylinder F, and there further expands and
acts to move the piston 4, and after its escape from the cylinder F it further acts upon
the piston of the largest cylinder C. By this construction a direct acting triple
expansion engine is secured with all the cylinders axially in line.
As the high pressure cylinder is supported by the bracket 2, at a distance from the
middle cylinder easy access may be had to the stuffing boxes of both cylinders, and
the cylinder E can be disconnected without disturbing the other parts of the engine,
while the forward cylinder F can be removed and replaced without changing the
position of the central cylinder, and as the latter only is directly connected with the
bed plate, the removal of the other cylinders does not necessitate any alteration in
the bed plate connections.
While any suitably constructed and connected valves may be employed, it is
preferable to operate one valve from the other. In the construction shown the valve
of the forward cylinder F is operated by steam pressure controlled by a rock shaft 17.
This shaft 17 passes down into an exhaust chamber, its end engaging with an oblique
slot in a block 17ª (see Fig. 1a) to which a reciprocating rotary motion is imparted
from the crank arm 25 through the connecting rod 27 which is attached to the cross-
head g. This motion will give an oscillating movement to the valve covering
alternately the passages which permit steam to pass to either end of the valve
chest to drive the chest pistons shown, x² 3 being exhausting passages for this
purpose.
The valve rod 18 of the cylinder F, is connected to and operates the valve of the
cylinder C, and a valve rod 19 from the latter valve is connected to operate the valve
rod 20 of the high pressure cylinder valve.
When it is desired to vary the throws of the valves, as for instance to use a valve
with shorter stroke on the high pressure cylinder, the connections are constructed to
secure this result. Thus the valve rod 19 is connected by a link 21 to a lever 22
pivoted to the bracket 2 at the lower end, and connected by a link 23, pivoted to the
lever centrally with the spindle 20 of the high pressure valve, which thus has half
the stroke of the other valves and derives its motion therefrom. All the valves are
thus driven by a single valve connection, the valve of the initial engine being moved
from that of the secondary engine, and the stroke of either may by like means to
those described be varied from that of the others to any extent desired. The prime
mover, however, of the valve motion can be operated from either valve chest, as is
obvious.
The engine if loaded could not be started from a state of rest by admitting the
high pressure only to the initial or high pressure engine. To start it therefore the
steam inlet pipe 29 (which communicates with the valve chest 14, and has the usua
throttle 30) may be connected by a pipe 31, (Fig. 2) provided with a valve 32, with
the exhaust port or pipe of the cylinder E, so that by opening the valve 32, the steam
may be directed, under full pressure to the secondary cylinder F, and after the engine
'is started the steam may be cut off directly from the secondary cylinder and admitted
to the cylinder E.

page_text: Live steam may be admitted to any one or more of the cylinders when starting,
by the introduction of suitable pass over valves connecting all or any of the cylinders,
as is apparent.
When it is decided to work two of these triple expansion direct acting engines in
double or duplex form, the valve motion will be operated, and the service of the
pumps, if the engine be used for pumping, be changed from single to duplex in the
manner described.
It will be understood that the precise construction and arrangement of parts shown
may be varied in different cases.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me by
my foreign correspondent, I declare that what I claim is :-
1. The combination in a triple expansion engine of a large cylinder C supported
upon the bed and two smaller cylinders one at each end of cylinder C, and axially
in line therewith, and supported wholly thereby, substantially as described.
2. The combination of the cylinder C, cylinder F supported by one head of said
cylinder, and a third cylinder connected by a bracket with the other head of the
cylinder C, substantially as described.
3. A triple expansion direct acting engine provided with three cylinders axially in
line, the pistons of the centre and forward engines connected by independent rods
with the cross head, and the rear and high pressure cylinder connected with the piston
of the centre cylinder, substantially as described.
4. The combination in a triple expansion engine, of three axially arranged cylinders,
each with a valve, the valve of one of the secondary cylinders connected to be
operated by a moving part of the engine and each valve connected directly with the
adjacent valve, substantially as described.
5. The combination of the three axially arranged cylinders, with valves, one
connected to be operated from a moving part of the engine, and connections between
the other valves constructed to vary the throws of the valves, substantially as
described.
6. The combination of the high pressure and two low pressure cylinders axially in
line, the valve of each cylinder connected with the next, the valve of one of the
secondary cylinders connected with the piston rod and the valve of the high pressure
cylinder driven from one of the other valves, substantially as described.
Dated this 18th day of January 1888