CERTAIN IMPROVEMENTS IN STEAM ENGINES AND BOILERS, AND IN MOTIVE MACHINERY CONNECTED THERE- WITH
Year: 1842

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, PERCEVAL
MOSES PARSONS, of Waterloo Road, in the County of Surrey, Civil Engineer,
send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Ninth day of December, in the sixth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Perceval Moses Parsons, my exors, adññiors, and assigns, Her especial license,
full power, sole privilege and authority, that I, the said Perceval Moses
Parsons, my exors, adñññors, and assigns, and such others as I, the said'
Perceval Moses Parsons, my exors, adiñiors, or assigns, should at any time
agree with, and no others, from time to time and at all times thereafter
during the term of years therein expressed, should and lawfully might make,
use, exercise, and vend, within that part of Her Majesty's United Kingdom
of Great Britain and Ireland called England, Her Dominion of Wales, and
the Town of Berwick-upon-Tweed, my Invention of "CERTAIN IMPROVEMENTS
IN STEAM ENGINES AND BOILERS, AND IN MOTIVE MACHINERY CONNECTED THERE-
WITH;" in which said Letters Patent there is contained a proviso that I, the
said Perceval Moses Parsons, shall cause a particular description of the nature
of my said Invention, and the manner in which the same is to be performed,
under my hand and seal, to be inrolled in Her said Majesty's High Court of
Chancery within six calendar months next and immediately after the date of
the said in part recited Letters Patent, as in and by the same, reference being
thereunto had, will more fully and at large appear.

page_text: NOW KNOW YE, that the nature of my said Invention, and the manner
in which the same are to be performed, are fully described and ascer-
tained in and by the following Specification thereof, reference being had
to the Sheets of Drawings hereunto annexed, marked A, B, and C, that
is to say:-
My said Invention consists of several parts, the description whereof is as
follows:-The first part consists of certain combinations and arrangements of
machinery, represented in Sheet A, Figures 1, 2, 3, 4, 5, and 6, of the
Drawings hereunto annexed, having for their principal object the better
application of high pressure steam to marine purposes.
Figure 1 is a longitudinal section of one of a pair of engines and
boilers, but with the boiler represented as out of its proper place, for the
purpose of showing its construction and connections more clearly. Figure 2
is a plan of the same, with the boiler in its proper place, the position
of the same being indicated by the blue lines. A is a boiler adapted to
the generation of high pressure steam, which is similar to those boilers
used for locomotive engines on railways. It is provided with a fire box and
smoke box, B and C, connected by tubes 15, through which the heated air
from the fire box B passes into the smoke box C, and up the chimney D; E
is a steam chamber of cylindrical form for connecting the boilers, where two
or more are used. Safety valves and guages are provided as usual, and there
is also a soft metal plug inserted in the crown of the fire box, so that, should
the water get low at any time, the fire would be extinguished before any
harm could arise. The steam, on passing from the steam chamber E along
the pipe 1, gives first off through the branch pipe 16, a quantity sufficient to
fill the space between the jacket T and the cylinder G, for the purpose of
keeping the working cylinder G warm; it then flows onwards through a con-
tinuation of the pipe 1, and down a pipe 17 to the space V, which encircles
the small cylinder U; from this space the steam is taken to work the engine,
but before doing so it is made to pass through the valve box S, the con-
struction of which is represented on an enlarged scale in Figures 3 and 4.
The object of passing the steam through this valve box is to reduce the
pressure of the steam when the engine is being worked by hand, and thereby
prevents steam of the same pressure as that in the boiler passing into the
large cylinder G, which would endanger the working parts of the engine.
The steam in the space I, between the cylinder and its jacket D, passes first
into the box K by the passages J, J, and thence, when the engine is at work,
through the opening G into the passage C, which communicates with the

page_text: valves r,, (Figure 1.) But when the valves of the engine are being
worked by hand, the slide E (Figures 3 and 4) is pressed down by the rod
L, so as to cover the opening G, and prevent the steam from entering through
that passage into the space C, while it is allowed to pass through the valve F,
which valve is pressed on its seat by means of a spiral spring M, with a force
equal to a pressure of about ten pounds on the inch less than the pressure of
the steam in the boiler, so that when steam of a greater pressure than ten
pounds is on the upper side of the valve, its pressure, combined with that of
the spring, will close it, and prevent any more steam being passed. The steam
thus reduced in pressure passes round the case N of the rod L, through the
opening H into the passage C, and thence to the valves r, r, Figure 1, as
before described; the steam is admitted by these valves alternately to the
top and bottom of the small cylinder U, and may be either cut off at any
convenient part of the stroke, or allowed to work with its full pressure
throughout the stroke. After having acted on the piston v, it is allowed
to pass by the passages 26 and 27 alternately from the top of the small
cylinder U to the bottom of the large cylinder G, its ingress being regulated
by the sliding valves 28, 28¹; and when it has acted on the top and bottom
of the piston H in the large cylinder G, it is allowed to pass from the top
of the cylinder G through the valve a, into the passages C, C, and from
the bottom of the cylinder G, through the valve a', up the passage b, into
the same passages C, C, whence it flows into the condenser Y, Y, where it is
finally condensed. A sectional elevation of the condenser Y, Y, is contained in
Figure 1. Figure 5 is an enlarged view of some of the parts thereof, and
Figure 6 a horizontal section or plan. It will be seen that it is composed of
corrugated plates of copper, but may be composed of any other suitable metal,
which plates occupy the space between the air pump W and the outside casing
23, with the exception of the spaces 29 and 30 (Figure 6), which are reserved
for the admission of cold water, which is caused by means of a pump or other
suitable contrivance to traverse the conduit f (Figure 1), and up the passage
29 (Figure 6), and then to circulate among the corrugated plates Y, Y, till it
reaches the space 30 (Figure 6), whence it passes out through the pipe d
(Figures 1 and 6). The construction will be still better understood by reference
to Figure 5. In that Figure E, E, are the corrugated plates, numbered for the
sake of distinction 1 to 12 inclusive. These plates are laid together in pairs
across each other, so that the corrugations of each plate shall be at right angles
to those of the plate next to it, or they may be placed in any other convenient
position. The edges of each pair of plates are brazed, soldered, or otherwise
securely fastened together at the top and bottom, and the reverse edges next

page_text: to the water spaces are secured in like manner. Thus, for example, the plates
2 and 3, and 5, 7 and 8, 9 and 10, 11 and 12, are secured at the top and
bottom edges, and the plates 1 and 2, 3 and 4, 5 and 6, 8 and 9, 10 and 11,
are secured at the edges which terminate in the water spaces 29 and 30
(Figure 6). The plates next the air pump are continued till they lap over one
another, and are nipped between the air pump and the flanges 22, 22, Figures
1 and 6. A farther continuation of the same plates is made to cover the top
and bottom of the water passages 29 and 30 (Figure 6), being there secured
by flanges 31, 32, 33 (Figure 1), and a circular flange 34 round the conduit
F, so as to allow a free passage for the cold water into the spaces 29 and 30.
D, D, Figure 5, is a plate full of small holes, which is laid on the top of the
corrugated plates for the purpose of dividing and breaking the force of the
steam as it passes through the spaces b, b, b, while the cold water is simulta-
neously passing at right angles through the spaces a, a, a, and serves to condense
the steam. The air pump W (see Figure 1) is double acting, and worked by
a small beam, but differs from those in ordinary use, inasmuch as none of the
water arising from the condensed steam is allowed to pass through it, being
kept exclusively for pumping the air and uncondensed vapour from the con-
denser through the bottom valves 20 and 20, and top valves 201, 20¹, and after-
wards discharging it through the passage e. Instead of a condenser, such as
that before described, being used, a condenser of the ordinary form may be
substituted, and the air pump be modified to suit it, as follows:-Let the bucket
of the pump be made like an ordinary piston, without valves, but let the pump
have two valves at the top and two at the bottom, the former for the purpose
of drawing off the air and uncondensed vapours, and the latter for the purpose
of drawing off the water by separate and distinct passages. In some cases I
use the top side of the plunger of the pump, with the top valves as a cold water
pump, for the purpose of supplying the condenser with water, when surface
condensers are employed, separate passages being provided for the same, while
the bottom side of the plunger and bottom valves are employed as an air pump
in manner before described. With respect to the condensed steam, it is drawn
off by a small pump h, of sufficient size to draw off not only all the water
arising from condensation, but also such as may accumulate from leakage or
other causes, and pump the same into the vessel k. Above the smoke box
C there is a chamber 36, through which the chimney D passes, and which
contains a float 3, which is connected with a valve 4, so that when there is a
sufficient quantity of water in the chamber 36, the valve 4 will be closed; but
when the case is otherwise, water will be admitted through the pipe 5, which
is furnished with a stop-cock 37. This water will be slowly evaporated by the

page_text: heated air as it passes into the smoke box C and chimney D, and the vapour.
thus produced will be conducted through the pipe 7 to a three-way cock 39,
which is so made that when the pipes 7 and 2 are in connexion, the pipe 6 is
closed; but when the pipe 2 is closed, the pipes 7 and 6 will be in communica-
tion, and will allow the steam from the boiler A to pass into the vessel 36, and
by its pressure opening the valve 4. clear the vessel 36 of all the water it con-
tains through the pipe 5. This cleansing operation, however, will be required
only occasionally, in order to prevent the water in the vessel 36 from being too.
much saturated with brine and other impurities. When the pipes 7 and 2 are
in communication, the vapour passes through them into the vessel k, where it
meets with the water pumped in as before mentioned by the pump h, and
becomes partially condensed. The whole is then drawn off by the pump 1, and
forced into the boiler through the pipe 7; but when there is sufficient water in
the boiler, by shutting the cock 19 the water will be forced through the valve
N (which is otherwise kept down under a considerable pressure by the aid of
a spring or any other suitable means), and passes through the pipe p into the
vessel F at the top of the boiler; and should the vessel F be also full, then the
water will escape through the valve 11 and pipe 12. It follows that the vessel
F should be always full of fresh water by the time it is required to stop the
engines, and when they are stopped the damper 14, which is made as nearly
air tight is possible is closed, by which means the fire may be at once put out,
or so much damped that no steam will escape at the safety valve; but should
the steam escape at the safety valve, and the water in the boilers get low, then
by opening the cocks 8 and 9 the steam will pass from the boiler up the pipe
10, and the water will descend by its own gravity into the boiler through the
pipe 38, and so keep the water from sinking below its proper level in the
boiler. It will be seen that by the preceding arrangements nothing but pure
water can be supplied to the boilers, and that the supply will be kept up for a
considerable length of time after the engines have ceased working. The force
which the steam exerts upon the small piston v is transmitted by means of a
piston rod t through a double link to the beam u, which is connected by
another link indicated by dotted lines to a pin 40, to which one end of the
connecting rod K is attached; the pin 40 is also fixed in a cross-head J attached
to two piston rods I, I, which take the power from the large piston H, to which
they are attached, the pistons acting by this means simultaneously on the crank
L, which crank turns the shaft M. When it is not convenient that the crank
and shaft should be immediately above the large cylinder, as represented in the
Drawings, they can be placed over and connected to any desirable point of the

page_text: beam u.
The main bearings, which are different from those ordinarily used
in marine engines, and are hereafter particularly described and claimed as
applicable generally to all marine engines, are here indicated by the letters
N, P, Q, Q, R, R, S, S, and figures 24, 25, and 41.
And with respect to the first branch of my improvements, which I have thus
herein-before described, I declare that I do not claim any one of the parts of
the preceding arrangements and combinations as being in and by itself new,
except as is immediately herein-after excepted; but that what I claim, as
separately and individually new, is,—
First, the surface condensing apparatus of corrugated plates before
described.
Second, the application, in manner before described, to steam engines
worked with any kind of surface condensers of an air pump, whether single or
double, acting to draw off the air and uncondensed vapours, and of another
and separate pump to draw off the water, also using the top of the air pump
and top valves as a cold water pump.
Third, the employment, in manner before described, in the case of engines
worked with common condensers of a double acting air pump, by means of
which the water arising from the condensed steam, together with the injection
water, are pumped out by the bottom valves, and the air and uncondensed
vapour are pumped out by the top valves.
Fourth, the method before described of supplying the waste of fresh water
consequent on the employment of surface condensers.
Fifth, I claim the application, in manner before described, to marine engines
of high pressure boilers, similar to those used for locomotive engines on
railways, in combination with surface condensers.
Sixth, I claim the application, in manner before described, to marine
purposes of high pressure boilers, similar to those used for railway locomotive
engines, in combination with double cylinder expansive engines of that class, in
which the steam is passed from a small cylinder into a larger.
Seventh, I claim the threefold combination, in manner aforesaid, of railway
locomotive boilers, double cylinder expansive engines of the class aforesaid, and
surface condensers.
3
Eighth, the valve apparatus, before described, for relieving the pressure of
the steam in double cylinder expansive engines of the class aforesaid, when a
they are being worked by hand.
Ninth, the arrangement, before described, whereby in the case of double
cylinder expansive engines of the class aforesaid, the steam in the small

page_text: cylinder may be cut off at any part of the stroke, and the communication
between the two cylinders is effected by passages different from those by which
the steam is admitted into the sinaller one.
Tenth, the employment where high pressure boilers of the railway locomo-
tive description are applied to marine purposes, and where there are two or
more used of a common steam chamber of communication, in manner before
described.
And, eleventh, the arrangement, before described, whereby in the case of
double cylinder expansive engines of the class aforesaid, the shaft is placed
above the two cylinders, and the beam or beams for transmitting the power
of the steam to the crank are also placed above the same cylinders.
The second branch of my Invention consists of the double cylinder arrange-
ment, represented in Figures 7, 8, 9, 10, and 11, Sheet A, of the Drawings
hercunto annexed, and which arrangement is applicable both to marine and
stationary land engines. Figure 7 is a cross section of an engine, with this
arrangement; Figure 8, a vertical section; and Figure 9, an horizontal section.
The steam is taken from the boiler by the pipe A, and passes into an
annular chamber C, C, between the two cylinders D, D, and E, E, and is
allowed to pass alternately into the top and bottom of the small cylinder D, D,
by means of the slide valves F, F. so as to give motion to the small piston G;
after the steam has worked the piston G, it is allowed to pass alternately fron
the top of the small cylinders D, D, into the bottom of the annual chambers
formed by the cylinders P, P, and E, E, and from the bottom of the small
cylinder D, D, into the top of the said annular chamber, so as to give thereby
motion to the large annular piston O, O, which acts simultaneously with the
piston G, H, I; and T, U, are the passages through which the steam passes
alternately to the top and bottom of the annular chambers, and K and L
the valve boxes. The slide valves are of the peculiar form separately
represented in Figures 10 and 11, and herein-after described. The steam,
after having worked the large annular piston, is passed through the openings
Qand R into the eduction pipe S, through which it passes to the condenser or
into the external atmosphere, as may be most convenient. The motion of the
annular pistons 0, 0, is communicated by two piston rods V and V, to a cross
head W, to which is likewise attached the piston rod X, of the small piston G;
from this cross head the motion of the engine can be transferred by means of
connecting rods, or any other suitable contrivances to all kinds of machinery.
Figure 10 is a section, and Figure 11 a plan, of the slide valves for working
the engines before referred to; A and B are two pieces of a wedge form, so
placed together that their outside edges shall be parallel and slide between two

page_text: parallel faces, E and D, which have two openings, F and G, one leading from
the cylinder, and the other leading to the eduction passage. The slides
A and B, when brought together, have an opening C, which corresponds with
the openings F and G. The slide in the position which it occupies in
Figures 10 & 11 allows the steam to pass on each side of it into the
passage I, which communicates with the top of the cylinder, and also allows
that which is in the annular chamber to go into the eduction passage G; but
when the slide is at the top of its stroke, the two passages F and I are closed,
while the space C in the slide is still left in communication with the eduction
passage G, and at the same time similar passages are opened by like slides
at the top of the cylinder. The slide rod K is attached to the wedge piece A,
and the wedge piece B is constrained to move with it by pieces L and M,
which are fixed to the piece A in such a manner as not to prevent the
tightening action of the wedge picces sideways, which is effected either by
springs or the pressure of the steam.
And with respect to the second branch of my Invention, I declare that what
I claim as new is,-
First, the double cylinder arrangement, before described, by which a small
cylinder is worked inside a larger in the manner shewn.
And, second, the wedge slide valves, before described, whether applied to the
preceding or any other sort of engine.
The third branch of my Invention consists of the improved single acting
expansive engine, represented in Figure 1, 2, and 3, Sheet B of the Drawing,
hereunto annexed. The steam passes from the boilers through the steam
pipe X to the space A, A, and thence through the expansion valve B along
the passage C, into the annular space D, formed by the two cylinders G and H.
The piston E is firmly attached to the top of the cylinder G, which is
stationary, and the piston F is attached to the cylinder II, and moves up and
down with it. The steam, when admitted into the annular space, presses
down the piston F, and with it the cylinder II, to which it is fixed, and may
be cut off at any convenient part of the stroke. After it has forced the piston
and cylinder F to the bottom of their stroke, the steam is then admitted
through the passage I, and an equilibrium valve K, into the large space L,
formed between the top of the cylinder G and the cylinder cover V, and is
there allowed to expand until it forces the cylinder H to the top of its stroke,
when it passes off by means of the exhaustion valve M into the condenser N, N,
where it may be condensed, either by cold metallic surfaces, as represented in
the Drawings and herein-before fully described, or by injection. The air
pump W is placed in the centre of the condenser, its plunger O being con-

page_text: nected to the cylinder cover by the rod Y. By means of the preceding
arrangement, the pressure of the steam in the annular space D combines with
the pressure of the atmosphere on the top of the cylinder cover V, to bring
the cylinder H with its cover V down, while the pressure of the steam in the
large space L, between the cylinder cover V and the top of the cylinder G,
serves to force them up. The reciprocating motion thus obtained may be
communicated to machinery, either by a pin on the cylinder cover, or by two
In the case of steam
pins, one on each side, or by any other suitable means.
boats, however, I prefer communicating the motion of the piston and cylinders
to the crank, by means of a rod attached to a pin in the cylinder cover, as
shown in the Drawing, Figure 1. By a slight alteration of some of the parts
of this engine, it may be converted into a common double acting condensing
engine; that is to say, by admitting the steam from the boiler alternately into
the spaces D and L, and then, after having worked the cylinder by suitable
valves into the condenser; or it may be converted into a single acting atmo-
spheric engine, by admitting the steam from the boiler direct into the space L,
and after it has forced the cylinder up, allowing it to pass into the condenser,
the cylinder descending, of course, by the pressure of the atmosphere on its
cover. Where surface condensers are used in engines, such as before described,
or in others for marine purposes, and where it is not convenient to work a
cold water pump, the cold water required for the condensers may be obtained
in the following manner-Let a pipe, communicating with the condenser or
condensers, be carried outside the vessel below the water line, at or near to
the bow, and as the vessel moves forward a current of water will flow through
them and the condenser or condensers, whence it may be passed out again
through another pipe at either of the sides or at the stern.
And with respect to this third branch of my Invention I declare, that I do
not claim generally the use of cylinders having a reciprocating motion, the
same having before been used; but that what I claim is, first, the application
of them in manner aforesaid, for all the purposes to which steam engines
may be applied; and, secondly, the arrangement whereby the condenser and
air pump are placed inside the working cylinder of the engine, one or both
of them.
The fourth branch of my Invention consists of the arrangements repre-
5sented in the Drawings, Figures 4 and 5, Sheet B, which has for its object
the better application of steam power to the driving of screw and other pro-
pellers applied to the stern of vessels. I connect the two large cylinders,
A, B, by means of pistons, piston rods, and connecting rods, as usual, to two
shafts, the centres of which are represented by the red circles C and D

page_text: which shafts carry spur wheels, represented by the circles E and F, each
driving a common pinion G, fixed on the propeller shaft, of which H repre
sents the centre. The common pinion G is so proportioned that it shall
make two revolutions to each revolution of the spur wheels E and F. The
piston of the small cylinder I is connected to a crank on the propeller shaft H,
by means of a piston rod and connecting rod, or by any other convenient
method, and will consequently make twice the number of strokes in the same
time as the pistons of the cylinders A and B. The steam, after having pressed
down the piston in the small cylinder, is admitted, by means of proper passages
and valves, alternately into the top and bottom of the large cylinder A; and
after the steam has been used to press up the piston in the small cylinder I,
it is admitted by similar valves and passages alternately into the top and
bottom of the large cylinder B. Then, after the steam has done its office on
the pistons in the large cylinders A and B, it is let out through the passages
K and L at the top, and similar passages at the bottom, into the eduction
passages M, from which it either passes into a condenser N, or into the
atmosphere.
Now, in respect of this fourth branch of my said Invention, I declare that
what I claim is, the using, in manner before described, of three cylinders, so
constructed, arranged, and worked, that the piston of one of them shall make
twice the number of strokes in the same time as the pistons of either of the
other two cylinders; these two cylinders being supplied with the steam from the
cylinder, the piston of which gives the greater number of strokes as aforesaid.
The fifth branch of my said Invention consists of the apparatus for discon-
necting the crank of marine engines from the paddle shaft represented in
Figures 11, 12, 13, and 14, Sheet B of the Drawings hereunto annexed.
Figure 11 is a section of the apparatus; Figure 12, an end view; and Figures
13 and 14, cross sections. The shaft A is forged hollow, and contains within
it a cog wheel B, working in two supports C and D, which are fixed by
means of bolts, as shewn in Figure 14. A rod E, having a screw cut on its
end, is screwed into the wheel B, into which an endless screw F works, to the
spindle of which is attached the handle G; on the end of the rod E is
attached the key H, which fits into a key-way in the shaft, the ends of it
extending a short distance into the crank I. When in the position represented
in the Drawings, the key H connects the two parts, and causes the shaft A to
revolve with the crank I; but when the shaft is to be disconnected, the endless
screw F, being turned round by the handle G, causes the wheel B to unscrew
the rod E, and forces it outwards, carrying with it the key H, and thus discon-
necting the crank from the shaft. K and L are two grooves which extend a

page_text: short distance into the crank, so that when the shaft is required to be con-
nected, should the key H not happen to be at the moment exactly opposite its
key-way in the crank, the ends of the key are screwed into these grooves, and
the crank eased round until it cannot go any further, when it is screwed in by
turning the handle G in the reverse way to that in which it was turned on
screwing it out.
And with respect to this fifth branch of my Invention, I declare that what
I claim is, the disconnecting the crank of marine engines from the paddle shaft
by means of a key made to slide as described.
The sixth branch of my Invention has for its object the diminution of the
quantity of fuel and water consumed by railway locomotive engines, by means
of a better application of the expansive principle to this kind of engines than has
been heretofore made. Figure 1, Sheet C, represents a section of one of a pair
of cylinders with its valve, together with a part of the boiler, and an elevation
of the necessary gearing for working the steam and expansion valves; Figure 2
is an elevation of the gearing for working the valves of the second cylinder.
The cylinders are provided, in the usual way, with pistons, piston rods, and
connecting rods, for the purpose of communicating the power of the steam to
two cranks at right angles to each other, on the same shaft or axle to which
the driving wheels of the engine are attached; Figure 3 is a plan which
shews the gearing for working the valves of both cylinders; Figure 4 is a
cross section of one of the cylinders. The steam from the boiler enters through
the pipe A into the valve box B, which box contains two flat sliding valves
I and K, attached to the same rod 3, for the purpose of cutting off the com-
munication between the boiler and the cylinder, so that the steam may act on
the piston by its expansive force. The rod 3 is connected to the lever 4 by
means of another rod 5, and the lever 4 is attached to a shaft 6, on which is
fixed another lever 7, which receives motion from the eccentric 8, through the
eccentric rod 9, 9. The eccentric rod 9, 9, can be made either to impart its
motion to the lever 7, as represented in the Drawing, or by raising it by the
lever 10 and link 11 to the lever 12, which is fixed on the shaft 13. The
eccentric 8 is fixed on the main crank shaft of the engine in such a position
that its centre 15 may make an angle of 45°, with a line drawn from the
centre of either of the pins 16 or 17, through the centre of the main shaft 14.
when the piston is at the top of its stroke. E and F are two valve boxes,
containing slide valves G and H, which are connected by the rod X, and
admit the steam alternately at the top and bottom of the piston 18, and allow
it to pass through the openings 22 and 23, into the eduction passage 24, and
blast pipe 25, into the atmosphere, after having performed its duty in the

page_text: cylinder. These valves are connected to the lever 1, by the rods Y, Z, which
lever is fixed on the weigh shaft 2, to which are also fixed two levers 22 and 23,
which receive motion from the eccentric L, by means of the eccentric rod M, which
terminates in two forks N, N', and a slot O. The eccentric L is fixed on the crank
shaft 14, at an angle of 90°, with a line drawn from the centre of the crank shaft
14 to the centre of the weigh shaft 2, when the piston is at the top of its
stroke. The forks N, N', serve to guide the pins R and S into their respective
notches in the usual way when the engine is reversed, or the contrary. A
roller P is placed in the slot O, and turns freely on a pin at the end of the
lever Q, which supports the weight of the rod M, and shifts it either on to the
pin R or the pin S, according to which way the engine is required to move.
This lever Qis fixed on the lifting shaft W, which receives its motion from
the lever T connected by the rod U to the reversing lever V, which is under
the control of the driver. The gear for working the valves of the second
cylinder, represented in Figure 2, differs but little from the gear employed to
work the other. The eccentrics 26 and 27 are placed in a similar position as
the eccentrics 8 and L, before described; and the eccentric rod 28 is similar
in every respect to the eccentric rod M, and communicates its motion to
two levers 29 and 30 on the weigh shaft 31, to which the lever 32 is fixed,
which gives motion to the slides similar to G and H, Figure 1, through the
rods 45 and 46, in the same way as before described. The rod 33, which is
fixed to slides similar to I, K, in Figure 1, receives its motion through the
rod 34, from a lever 35, fixed on the weigh shaft 13, on which is another
lever 36, to which the eccentric 27 gives its motion through the rod 37. The
eccentric rod 37 can also be made to impart its motion to the lever 38 on the
shaft 6, by lifting it up, the fork 47 guiding the pin 44 into the notch
provided for it. The lever rods, &c. are shewn in such a position as to make
the cranks and shaft revolve in the direction shewn by the arrows; but when
it is required to reverse the motion of the engines, the rod U is moved by
means of the reversing lever V in the direction indicated by the arrow, causing
the lever T to turn the shaft W on its centre. The motion thus commu-
nicated to W passes down the levers Q, 39, and 40; the lever causes the
rods M and 28 to move off the respective pins R and 30 on to the pins S and
29, thereby reversing the steam slides G and II, and similar ones in the other
cylinder. At the same time, the small levers 39 and 40 cause the levers
10 and 41 to move about their respective centres 43 and 42, and thereby the
eccentric rods 9, 9, and 37 to move off the pins 16 and 36 on to the pins 17
and 44. It will be seen that by this arrangement the eccentric 8 will work the
expansion slides of the opposite engine, and vice versa, thereby reversing the

page_text: expansive slides of each cylinder. The valves I and K may be made either in
one piece or two; but I prefer making them in two, for the purpose of
adjusting the expansion to any required degree. To keep the steam warm
during its action in the cylinder, I use a jacket 45, and allow the steam from
the boiler to have free access to the space between it and the cylinder, and
likewise in some cases to the spaces 46 and 47, at the top and bottom of the
cylinder. The whole of the jackets and steam spaces may, if thought con-
venient, be clothed in felt. The arrangement for working and reversing the
expansion valves, herein-before described, may be applied to work the ordinary
valves of locomotive engines when the lead of the eccentrics amounts to an
angle of 45°, whereby two of the four eccentrics now generally employed may
be dispensed with.
And with respect to this sixth branch of my Invention, I declare that what
I claim is,-
First, the application to locomotive engines of a separate slide valve or
valves, for the sole purpose of cutting off the steam from the boiler to the
cylinders at any convenient part of the stroke, its entrance into and exit from
the cylinders being regulated at the proper times by means of another valve
or valves separate from and unconnected with the former valve or valves.
Second, the using, in manner before described, of distinct and separate slide
boxes and valves for effecting and regulating the entrance and exit of the steam
on each side of the piston in locomotive engines.
Third, the placing of the eccentrics of locomotive engines in such a position
on the crank shaft that the eccentric of one engine can be made to work
either the expansion or ordinary steam valves of the other engine when the
engines are required to be reversed.
Fourth, the several arrangements and combinations of parts, Figures 1, 2,
3, and 4 of Sheet C of the Drawings hereunto annexed, having for its object
the better application of the expansive principle to the working of railway
locomotive engines, of which parts some to the extent before specified are new,
and others old, but the whole are newly combined for the object aforesaid.
And fifth, I claim the keeping of the cylinders of locomotive engines warm,
in the manner before described.
The seventh branch of my said Invention consists of an arrangement for
working the expansion valves of a cylinder similar to Fig. 1, Sheet C, by
means of which no reversing gear will be required for the expansive slides, as
in the arrangement before described.
A (Figure 5) is the crank shaft, and B
a cam fixed thereon, which, as it revolves, acts upon two rollers C and D,

page_text: fixed in a frame E, E, which terminates in a rod G, connected to a lever on
the weigh shaft; the cam is so formed that a line drawn through its centre
from edge to edge will be of the same length in any point, because whenever
there is a projection there is a corresponding indentation on the opposite side,
and the length of these corresponding projections and indentations are regu-
lated according to the time at which the steam is required to be shut off. The
position of the cam, as shewn in the Drawing, would be the proper position
for it when the engine is at the end of its stroke, as represented in Figure 1,
so that in whichever way the shaft moves, the same motion will be communi-
cated to the rod G, and from it to the expansion slide, whereby the steam will
be cut off.
And in respect to this seventh branch of my Invention, I declare that what
I claim is, the use of cams, in the manner represented in Figure 5, Sheet C,
and before described, for the purpose of working an extra slide valve for the
purpose of cutting off the steam in locomotive engines.
The eighth branch of my said Invention consists in the improved modes of
supporting the main plummer block of marine engines, represented in Figures
1, 2, and 12, Sheet A. In the elevation, Figure 1, and plan, Figure 2,
Sheet A, V is the plummer block which carries the shaft N; it is supported
by a single column P, and may be either fixed to the cylinder or the foundation
plate of the engine; Q, Q, are the struts; S, S, the props attached to the main
beams of the vessel; and R, R, two strong tension rods, which are carried at a
considerable angle from the main plummer block to the foundation plate of
the engine, and firmly secured thereto; 25, 25, are stretcher bolts, which run
parallel to the main beams of the vessel, and serve to tie together the ends of
the struts Q, Q, Q. Q; 24, 24, are diagonal cross braces between the engines,
which keep the plummer block from winding, as do also the diagonal braces
41, 41. A modification of the preceding plan, which may in some cases be
advantageously adopted, is shewn in Figure 12, Sheet A; A is a shaft, and B
a plummer block resting on two inclined columns C, C, firmly keyed into
sockets D, D, cast in the foundation plate E, or otherwise firmly secured.
The plummer block is provided with struts F, F, which connect it to the main
beams of the vessel, and which are further supported by means of props G, G,
fixed to them, and secured to the columns by the stretcher bolt H.
And in respect to this eighth branch of my Invention, I declare that what I
claim is the two improved modes of supporting the main plummer blocks of
marine engines Lefore described.
The ninth brauch of my said Invention consists in the improved metallic

page_text: packing for the pistons and stuffing boxes of steam engines, represented in
Figures 6 and 7, sheet B, of the Drawings hereunto annexed. Figure 6 is
a sectional plan, and Figure 7 an elevation, of a packing ring for a piston,
which, it will be observed, consists of two rings A and B, one of which, A, is
made of cast iron, and the other, B, of wrought iron; or they may be made
of any other two metals which do not expand equally by equal increments of
temperature. The two rings are firmly rivetted or otherwise strongly secured
to each other. The ring that expands the most should be placed inside the
other when used for common pistons; but when used for annular pistons, such
as are represented at F, Figures 1 and 2, the one that expands the most
should be placed outside the other. As the rings are heated by the steam,
their unequal expansion causes them to press outwards in the common piston,
and to press inwards in the annular piston. The same metallic compensating
system may be also substituted for the hemp packing in stuffing boxes.
And in respect to this ninth branch of my Invention, I declare that what I
claim is, the improved metallic packing for pistons and stuffing boxes of steam
engines before described.
The tenth branch of my Invention consists of the improved cock and plug
for steam engines represented in Figures 8 and 9, Sheet B, of the Drawings
hereunto annexed. Figure 8 is a section, and Figure 9 a sectional plan, of
the same.
Instead of the plug being of a regular conical shape as usual, it
is made with its sides slightly curved inwards for the purpose of compensating
for the greater wear of the larger end of the cone.
The eleventh and last branch of my said improvements consists of the plan
represented in Figure 10, Sheet B, of the Drawings hereunto annexed, for
preventing cams when used for working the valves, in place of eccentrics in
marine steam engines, from turning round with the shaft till the stop is in its
proper position when the engine is being reversed. A is the shaft; B, a cam;
C, a brake attached to the lever D, which works on a pin G, fixed to any con-
venient part of the framing of the engine. E is a stop on the shaft A. By
tightening the brake C by means of the lever D, the cam is secured till the
stop E arrives at the end of the notch F, when it is carried round with it.
The stop and notch are so arranged, that when the stop is at one end of the
notch, the cam will be in a proper position for working the slides when the
engine is going forward, and vice versa.
And with respect to this eleventh branch of my Invention, I declare that I
do not confine myself to the particular arrangement of parts shewn in
Figure 10, which may be variously modified; but that what I claim is, the
use of a brake for the purpose of holding the cams in marine engines until

page_text: the stop on the shaft comes to its proper position when reversing the engines,
or the contrary.
In witness whereof, I have hereunto set my hand and seal, this Eighth
day of June, One thousand eight hundred and forty-three.
PERCEVAL MOSES (L.S.) PARSONS.
AND BE IT REMEMBERED, that on the Eighth day of June, in the year
of our Lord 1843, the aforesaid Perceval Moses Parsons came before our said
Lady the Queen in Her Chancery, and acknowledged the Specification afore-
said, and all and everything therein contained and specified, in form above
written. And also the Specification aforesaid was stamped according to the
tenor of the Statute made for that purpose.
Enrolled the Eighth day of June, in the year of our Lord One thousand
eight hundred and forty-three.