IMPROVEMENTS IN VALVE ACTUATING ARRANGEMENTS FOR STEAM ENGINES
Year: 1886

page_text: Date of Application, 23rd July, 1886
Complete Left, 25th Apr., 1887.
Complete Accepted, 27th May, 1887.
RESERV
DAVID DONALD Engineer Penryn County of Cornwall do hereby declare the nature
of my invention for IMPROVEMENTS IN VALVE ACTUATING ARRANGEMENTS FOR STEAM
ENGINES to be as follows:-
The object of this invention is to cause one steam engine to regulate the movement
of another steam engine, so that two or more engines may run in harmony, it also
does away with all excentrics or other complicated gear for controlling the valves of
two or more engines working in harmony. The invention will be best understood by
reference to the accompanying drawing, where 1 and 2 are two steam cylinders,
supposed to be connected to the same crank shaft with cranks set at an angle of 45°,
the pistons are 10 and 2° respectively. For each cylinder there are three valves
(piston valves, as shewn; are preferable; but slide valves may be used actuated by
pistons) two of these are for regulating the steam supply and one for regulating
the exhaust. The valves for No. 1 cylinder are A. B. C. those for No. 2 cylinder
are A B C¹, the centre or exhaust valves are made less in diameter than the steam
valves as shewn.
Four ports are led from the valve chest of No. 1 cylinder to cylinder No. 2,
and four ports from the valve chest of cylinder No. 2 to cylinder No. 1. these are
shewn in dotted lines. Live steam, or other fluid under pressure; is led into the
valve chests of both cylinders by the pipe S.
The action is as follows: As the piston 1° moves in the direction of the arrow, it
uncovers the port E, which admits live steam, or fluid under pressure; to act in the
underside of the piston valve (", and moving it over, admits live steam to the underside
of the piston 2°. This piston moves in the direction of the arrow, and live steam is
admitted through the port D to the space between the piston valves B and C and
moves the valve C down, thus cutting off the supply of steam to the piston 1° at the
same time the valves A & B are kept up and the exhaust from the top of 1° is free to
pass into the atmosphere or condenser, through the port X.
When 1° piston reaches the end of its stroke and 2° piston is about half stroke,
the port F is uncovered by piston 2° this admits live steam to the top of valve A of

page_text: No. 1 cylinder, and although the underside of the valve B has pressure acting on it,
due to the port D admitting the live steam from the underside of 2° piston; the
live steam acting on the larger area moves the valves A & B down, thus admitting live
steam to the top side of 1° piston and placing the underside open to the exhaust ✗.
When the live steam is admitted to the top side of 1° piston, steam is admitted through
the port Y to the top side of the valve C₁ of No. 2 cylinder and moving it down, cuts
off the supply of steam to that piston, the valves A & B¹ remaining up as shewn on
the drawing and leaving the top of 2° piston open to the exhaust.
The position now is, 1° piston is moving down with live steam on the top and open
to the exhaust on the underside. 2° piston is moving up, the live steam has been cut
off about half-stroke and it is now expanding, the top side of the piston is open to the
exhaust. When 1° piston reaches half stroke down, it uncovers the port E¹, admitting
live steam to the top of valve A' of No. 2 cylinder and moving it down, thus
admitting live steam to the top of 2° piston in readiness for its down stroke, and
the valve B being moved over with it, the lower side of 2° piston is opened to the
exhaust X. 2° piston now begins its down stroke and uncovering the port G live
steam is admitted to the space between the valves A & B and as the top of valve A is
open to the exhaust by the port F, the valve A is moved up, cutting off the supply of
live steam to piston 1°. 1° piston is now moving down with steam working expansively,
2° piston is moving down with live steam on top. The underside of both pistons is
open to the exhaust. When 1° piston reaches full stroke down and 2° piston is about
half stroke down, the port F¹ is uncovered by 2° piston, admitting live steam to the
underside of valve C and moving it and valve B up, thus admitting live steam to
the underside of 1° piston in readiness for its up stroke and putting the top of the
piston 1° in communication with the exhaust-No. 1° piston uncovering the port H
and admitting five steam to the space between the valves A¹ & B¹, and moving the
valve A¹ up, cuts off the supply of live steam to the top side of 2° piston, while
the valve B' being still down, the underside of the piston 2° is open to the exhaust.
A complete double stroke or revolution has now been described. By this improvo-
ment steam or other fluid under pressure can be worked expansively. By altering
the positions of the ports G & H, G¹ & D in their respective cylinders, steam can be
cut off at any point between half stroke and full stroke.
Reversing of the engines is effected by leading the small ports, which connect the
valve chests with the opposito cylinders; into a suitable valve; so constructed that
the direction of the steam may be reversed and act on the opposite side of the piston
valves or on opposite valves as the case may be and thus reverse the action of the
main pistons.
1000

page_text: COMPLETE SPECIFICATION.
Improvements in Valve Actuating Arrangements for Steam Engines.
I, DAVID DONALD, Engineer, of Penryn, in the County of Cornwall 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 and
accompanying drawing, (that is to say):-
:-
My invention relates to that class of valves for Steam Engines actuated by the
pressure of steam or other clastic fluid, in which two or more principal cylinders are
so connected together that the piston moving in one of them regulates, by means of
passages and ports opened by it at the proper times, the valve of the other cylinder or
cylinders and vice versa.
It has for its object improved methods of constructing and arranging such valve
actuating devices, so that they are simple, and easily made and used, and so that the
steam or other elastic driving fluid can be worked expansively, and the engines can be
readily reversed when desired.
All excentrics or other complicated gear for controlling the valves of two or more
engines working in harmony together as described are done away with.
The accompanying drawing is in illustration of my invention, and represents a
section through the steam cylinders of two Engines working together, their piston
rods being supposed to be connected in the usual way to cranks upon the same crank
shaft these cranks being set at right angles to each other. The two cylinders aro
marked No. 1, and No. 2, and their corresponding pistons are marked 1° and 2°
respectively.
Each cylinder is provided with three separate distributing valves which in the
drawing are shewn in the form of piston valves which I prefer, but they may be mado
in the form of slide valves of the ordinary kinds actuated by pistons if preferred.
Two of these three valves are for regulating the admission and cut off of the steam,
and the thread is for regulating the exhaust.
The valves for cylinder No. 1 are marked a, b, c, and those for cylinder
No. 2, a, b, c, the three valves for each cylinder being in line with each other as
shewn, but the centre or exhaust valves b, 61, being of less diameter than the outer or
steam valves.
Four passages, shewn in dotted lines, communicate from four ports in the valve
cylinder or chest of No. 1 cylinder to four corresponding ports d, f, f, g, in the
positions shewn in No. 2 cylinder, and four similar passages communicate from ports
in the valve cylinder or chest of No. 2 cylinder the four corresponding ports h, e, e¹, y,
in cylinder No. 1.
Live steam from a boiler or other source of supply
or cylinders through the supply pipe s. The ports
pipes.
admitted to the valve chests
communicate with the exhaust
The action of the apparatus is as follows:-The piston 1° being in the position

page_text: shewn and moving in the direction of the arrow, when at about half stroke has just
uncovered the port e, through which steam or other elastic driving fluid passes
through the passage leading from it to the lower end of the valve chest of the opposite
cylinder No. 2, below the piston valve c¹ which it raises into the position shewn thus
admitting steam from s below the piston No. 2 which is at the bottom of its stroke as
shewn. This piston No. 2 accordingly commences its stroke in the direction of the
arrow, steam at the same time passing through the port d and along the passage
connected with it to the space between the piston valves b and c in the steam chest or
cylinder of No. 1 cylinder, and the valve c is accordingly forced down into the position
shewn, the valves a and b being at the same time kept up as shewn. The supply of
steam below piston 1° is therefore cut off and it continues its stroke by expansion,
the space above remaining connected with the exhaust or condenser through the
port, as long as the valves a and b remain up.
When piston 1° has thus reached the top of its stroke and piston 2° is consequently
at about half stroke the port fis uncovered by the latter, steam being then admitted
through it and through the passage connected with it to the top of the valve chest or
cylinder of cylinder No. 1 above the valve a, and though the centre valve & continues
to be pressed up against the valve a by the steam passing through the port d, the
valve a being of larger area than the two are forced down by the steam acting
above a with a force equivalent to the difference between their areas, steam from &
being thus admitted above piston 1° in cylinder No. 1 whilst the lower end of the
cylinder below the piston is put in communication with the exhaust port through
the valve b.
Steam at the same time passes through the port y to the steam chest or cylinder
of No. 2 cylinder above the lower valve which is forced down thus cutting off the
supply of steam below piston 2° which continues its stroke by expansion, the space
above it continuing in communication with the exhaust port a through the valve 61
which, with the upper valve a¹, remains in the position shewn.
Piston 1° is now commencing its down stroke with live steam admitted above it,
whilst the cylinder below it is open to the exhaust.
Piston 20 is at the same time completing its upstroke, by the expansion of the
steam below it which has been cut off at about half stroke, the upper end of the cylinder
No. 2 being in communication with the exhaust. When piston 1° has made half
its down stroke it uncovers the port e¹ through which steam passes to the upper end
of the valve chest or cylinder of cylinder No. 2 above the valve a¹ which it forces
down, thus admitting steam from s above tlio piston 2° in readiness for the latter to
commence its down stroke, the valve being forced down with it and thus opening a
. communication from the lower end of cylinder No. 2 to the exhaust x.
Piston 2°
accordingly commences its down stroke, steam at the same time passing through the
port g to the valve chest or cylinder of cylinder No. 1, between the valves a and b,
and as the space above the valve a is open to the exhaust through the passage and
corresponding port f, the valve a is forced up, thus cutting off the supply of steam
from above piston 1° which continues its down stroko by expansion, piston 2° con-
tinuing its down stroke, and the space below both pistons being open to the exhaust
ports x, x.
When piston 1° reaches the bottom of its stroke, piston 2° is at about half stroke
and uncovers the port f¹ through which steam passes by the passage to the lower end
of the valve chest or cylinder of cylinder No. 1 under the valve c, and forces up the
latter together with the valve thus admitting steam from s below piston 1° in
readiness for the latter to commence its upstroke, at the same time putting the upper
end of cylinder No. 1 above the piston in communication with the exhaust & through
the valve b.
Piston 1° then commences its upstroke, steam at the same time passing through the
port h and the passage communicating with it to the valve chest or cylinder of No. 2
cylinder between the valves a¹ and b¹, forcing the valve a¹ up and thus cutting off the
steam from the upper end of cylinder No. 2 the piston 2 in which continues the
remainder of its downstroke by expansion, whilst the valve 6' remains at the bottom

page_text: of its stroke so that the space below the piston 2° continues in communication with
the exhaust x.
By the cycle of operations described a complete double stroke of the pistons and
one revolution of the shaft have been effected, the steam having been automatically
distributed to the cylinders at the proper times and cut off at half stroke.
By altering the position of the ports y, h, g, and d in the respective cylinders the
steam can be so cut off at any desired point.
In order to reverse the Engines, the small passages which connect the valve chests
or cylinders with the opposite steam cylinders as described, are provided with a
suitable reversing valve by which the direction of the steam can be reversed so that it
acts upon the opposito sides of the piston valves to those shown, or upon opposite
valves, so that the action of the main pistons is reversed in the way required.
It is not necessary that the pistons should be connected to cranks upon a shaft as
described. For instance the piston rods may be connected to the plungers or buckets of
direct-acting pumps, each cylinder being independent of the other except that its valves
are regulated by the other Engine in the manner described. In this way a continuous
flow of water would be obtained from the pumps, one piston being at half stroke
whilst the other is at the end of its stroke and vice versa.
A direct acting duplex steam pump is thus obtained, with the advantago that the
steam is used expansively.
The inner ends of the valves a, a¹, c, c¹, are preferably made of such length as
shewn, that the passages to the exhaust ports a, a, are always closed before the steam
ports are opened.
Instead of two cylinders, pistons, and valves, as described and shewn, three or more
may be used, constituting separate engines all working in harmony together.
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 Engines in which the distributing piston valves or pistons operating slide
valves of one cylinder are actuated by steam or other driving fluid admitted from
another cylinder through ports and passages opened and closed at the proper times by
the piston in the latter cylinder, the use for each cylinder of two separate distributing
valves and one exhaust valve, substantially in the manner and for the purpose described
and shewn in the drawing.
2. The arrangement of two separate distributing valves and one exhaust valve, to
each cylinder, in combination with ports and passages from the adjoining cylinder, so
arranged that the distributing valves cut off the steam or other driving fluid, at any
desired part of the stroke of the piston, without actuating the exhaust valve,
substantially as described and shewn in the drawing.
DJ 1 1
c A
11007
EDWARDS & Co.,
35, Southampton Buildings, London,
Agents for the Patentee.