Improvements in Marine Steam Engines.
Year: 1892

page_text: Date of Application 22nd Mar., 1892
Complete Specification Left, 21st Dec., 1892-Accepted, 21st Jan., 1893
PROVISIONAL SPECIFICATION.
Improvements in Marine Steam Engines.
I, RESTEL RATSEY BEVIS, of Birkenhead Iron Works, Birkenhead, in the
County of Chester, Engineer, do hereby declare the nature of this invention to be
as follows:-
In many cases and especially for ships of war it is desirable to be able either to
propel the vessel at full speed or to propel it very economically at a low speed.
For this purpose according to this invention the crank shaft is made in two parts
which can be connected and disconnected at pleasure and the steam connections are
so arranged that the after cylinder or cylinders can alone be used the forward
cylinder or cylinders being disconnected.
In a triple expansion engine the following arrangement is adopted :-the engine
has four cylinders, the high, the intermediate and two low pressure, all four cranks
being at right angles to each other. The two low pressure cylinders are forward of
the others and the division in the crank shaft is just aft of them.
When running
at full speed all four cylinders are used in the ordinary manner but when it is
desired to run economically at a low speed the forward portion of the crank shaft
(and with it the two low pressure cylinders) is disconnected so that the propeller
is driven by the high and intermediate pressure cylinders only the steam also for
the sake of economy being used more expansively than when the other two cylinders
were also in use.
In order that the bearings of the crank shaft may be more evenly worn down the
propeller may sometimes be driven by the two low pressure cylinders alone the
rods of the high and intermediate pressure cylinders being disconnected from
the crank shaft.
Dated this 22nd day of
22nd day of March 1832.
COMPLETE SPECIFICATION.
Improvements in Marine Steam Engines.
I RESTEL RATSEY BEVIS, of Birkenhead Iron Works Birkenhead in the
County of Chester 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 :-
In many cases and especially for ships of war it is desirable to be able either to
propel the vessel at full speed or to propel it very economically at a low speed.
For this purpose according to this invention the crank shaft is made in two parts
which can be connected and disconnected at pleasure and the steam connections are
so arranged that the after cylinders can alone be used the forward cylinders being
disconnected.
The following arrangement is adopted :-the engine has four cylinders, the high
the intermediate, and two low pressure, all four cranks being at right angles to
each other. The two low pressure cylinders are forward of the others, and the
division in the crank shaft is just aft of them. When running at full speed, all
four cylinders are used in the ordinary manner, but when it is desired to run
economically at a low speed the forward portion of the crank shaft (and with it the
two low pressure cylinders) is disconnected so that the propeller is driven by the
high and intermediate pressure cylinders only the steam also, for the sake of
economy being used more expansively than when the other two cylinders were also
in use.

page_text: In order that the bearings of the crank shaft may be more evenly worn down,
the propeller may sometimes be driven by the two low pressure cylinders alone, the
rods of the high and intermediate pressure cylinders being disconnected from the
crank shaft.
In the accompanying drawings which illustrate my invention
5
Figure 1 is an end elevation of my improved marine steam engine looking on
the low pressure cylinder and aft towards the high pressure cylinder and propeller
shewing the end views of the bed plates containing the main bearings, the crank
shaft, the supporting columns of the low pressure cylinder, the low pressure cylinder
with the steam-stop reducing valve 2, for admitting the steam from the boilers at a 1
pressure suitable for working the said cylinders, the eduction pipes leading there-
from to the condenser, the reversing gear for reversing the engines from ahead to
astern movement or the opposite, the outer portion of the piston rod, the guides,
the connecting rod, and the air pump.
Figure II is a front longitudinal elevation of my said improved marine engine,
showing the bed plates which contain the main bearings for supporting the crank
shaft, the crank shafts with their connecting or disconnecting coupling, the
supporting columns of all the steam cylinders, the steam cylinders in the order in
which I prefer to arrange them, first the high pressure cylinder aft, nearest the
propeller, second the intermediate pressure cylinder, third, one of the two low
pressure cylinders, and fourth the other low pressure cylinder, also the steam stop
reducing valve 2, the regulating steam stop valve 3, the stop valve 7 the reversing
engine and reversing shaft, the eccentric gear for driving the main valves of the
engines, the guides, the connecting rods, and the two air pumps with their gear
behind.
Figure III is a plan looking on the top of the cylinders, which shew the cylinders
in the same relative position to each other, as in Figure II, and as I prefer to
arrange them, the steam stop reducing valve 2, the regulating steam stop valve 3,
the stop valves 7 and 19, the arrangement of steam and eduction pipes, the crank
shafts with their connecting and disconnecting coupling dotted underneath, the
reversing shaft and the two air pumps.
Throughout the accompanying drawings the same parts are indicated by the
same letters and figures. 1 is the main steam pipe for conveying the steam from
the boilers, through the upper part of the steam stop reducing valve 2, to the
regulating steam stop valve 3. 1st in the case when the engines are all connected
together, and working as a tri-compound engine at or about full power, the steam
stop reducing valve 2, is shut, and the regulating steam stop valve 3 is open, and is
admitting the normal full boiler pressure to the high pressure cylinder 4, from
which it is led through the eduction pipe 5. to the intermediate pressure cylinder 6,
and from thence through the stop valve 7. which is open by the eduction pipe 8 to
the two low pressure cylinders 9 and 10. and finally through the eduction pipes 11
and 12, to the condenser. (The condenser with the stop valves at ends of pipes 11
and 12, are not shewn in these drawings.) Also the parts of the reversing
shaft 13 and 13' are connected together at their couplings 14 and 14' and work as
evement, or the opposite
one shaft in reversing the engines from ahead to aster
further the crank shafts 15 and 15' are connected together by the coupling 16 and
lastly both the air pumps 17 and 18 are working to maintain the vacuum by with
drawing the water and air from the condenser, delivering the water to the boile
feed water pumps (which are not shewn in these drawings) and allowing the air t
freely escape.
2nd. When the high and intermediate engines are working together as
bi-compound engine and so propelling the ship at a low power for the purpose o
saving coal, or being compelled to work them in that way for the reason of the lo
pressure engine being disabled in an engagement as might happen in ships of wa
or by its being disabled for other reasons, in this case the steam pressure of th
boilers may be maintained at its normal working pressure, or be considerably belo
it, in any case the steam will be conveyed from the boilers by the main stea
"

page_text: pipe 1 through the upper part of the steam stop reducing valve 2, to the regulating
steam stop valve 3, which is open, and admits the steam to the high pressure
cylinder 4, and from thence through the eduction pipe 5 to the intermediate
cylinder 6 and finally through stop valve 19, and the eduction pipe 20 to the con-
denser. The stop valve 7 is now shut to prevent the steam from the intermediate
cylinder 6, passing to the low pressure cylinders 9 and 10. also the reversing
shaft 131 is disconnected at its coupling 14' so that when the bi-compound engine is
being reversed, the shaft 13' and its valve gear on the low pressure cylinders 9 and
10. will remain stationary in mid gear or otherwise as the engineer may require.
Also the crank-shaft 15 will be disconnected from the after crank shaft 15, by the
disconnecting coupling 16, and lastly the air pump 17 only will be working to
maintain a vacuum in the condenser.
3rd. When the two low pressure engines are only working, which may be
necessary for reasons similar to those which made it desirable that the high and
intermediate pressure engines should work together as a bi-compound engine or for
the purpose of wearing the main bearings evenly with those of the bi-compound
engine after it has been working alone for some time. In this case also the steam
pressure within the boilers may be maintained at its normal working pressure or be
considerably below it; in any case the steam will be conveyed through the main
steam pipe 1 to the steam stop reducing valve 2 and to the outside of the steam
regulating stop valve 3 only; this valve being shut in this case, while 2 will be
open, and will reduce the boiler pressure of the steam to the pressure suitable for
working the two low pressure engines as it passes through it. In the case of small
engines, one steam stop reducing valve will be sufficient, but in large engines I may
require to use two or more of these valves.
The steam therefore after passing 2 will enter valve casing 21, and will be
admitted simultaneously to each of the low pressure cylinders 9 and 10, and then
will pass through the eduction pipes 11 and 12, to the condenser. This condenser
and the stop valves to pipes 11 and 12 are not shown on the drawings. In this
case the stop valve 7 is shut to prevent the steam, after it has passed the steam
stop reducing valve 2 from passing into the intermediate cylinder 6, and the stop
valve 19, is also shut to disconnect the same cylinder from the condenser. Also
the reversing shaft 13 is disconnected from 13¹ at its coupling 14, so that when the
low pressure engine is being reversed from ahead to astern movement or the
opposite, the reversing shaft 13 and its valve gear on cylinder 4 and cylinder 6,
may remain at rest in mid gear; but the crank shafts 15 and 15, will be connected
together by their coupling 16. The connecting rod 22, of cylinder 4, and 23
that of cylinder 6 may be disconnected from the crank pins of the crank
shaft 15, if the engineer have an opportunity, but if not, they will be driven
harmlessly up and down until he has. Lastly, the air pump 18 only will be working
to maintain the vacuum in the condenser.
In the accompanying illustrations, the air pumps 17 and 18 are shown to be
worked by the main engines, but they may also be worked by independent engines,
in which case I may employ two or more air pumps, and these will always be
working to maintain the vacuum in the condenser independent of any power
changes in the main engines which are illustrated in the accompanying drawings;
but if I make two separate independent engines to work a separate set of air
pumps, then in this case one of the sets may be stopped.
The under bushes of the main bearings numbered 24 to 30. will preferably be
made flat bottomed, and the bed plates numbered 31 to 37 will be made to fit them,
so that thin liners may be introduced between the bush and the bed plate, when it
is necessary, so as to maintain a perfect line of shafting.
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 :-
1st. A tri-compound engine with four cylinders in combination with a four

page_text: cranked shaft with the cranks set at right angles to each other or thereabouts,
made in two pieces, with two cranks in each piece, capable of being connected or
disconnected by a coupling, a reversing shaft in two or more parts, capable of
being connected together or disconnected by a coupling or couplings and two air
pumps, all made to work together as a whole for the highest power which the
engines can develope, and of being divided into two sets of engines which can
work independently at different times, when required for low power substantially as
described.
2. The arrangement of a steam stop reducing valve or valves in combination
with the two low pressure engines whereby the high pressure boiler steam may be
reduced to work the two low pressure engines independently of the cylinders which
together form the bi-compound engine substantially as described.
3. The improved marine engine substantially as described and illustrated in the
drawings.
בד.
1000