CERTAIN IMPROVEMENTS IN THE CONSTRUCTION OF ENGINES OR MACHINERY (TO BE WROUGHT BY STEAM OR OTHER ELASTIC FLUIDS). APPLICABLE TO THE DRIVING OF MILLS AND OTHER USEFUL PURPOSES
Year: 1819

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
LILLEY, of Brigg, in the County of Lincoln, Gent", send greeting.
WHEREAS His most Excellent Majesty King George the Third of blessed
memory, by His Letters Patent under the Great Seal of Great Britain, bear-
ing date at Westminster, the Twenty-third day of November, in the sixtieth
year of His reign, did, for Himself, His heirs and successors, give and grant
unto me, the said George Lilley, my exors, adñiors, and assigns, His especial
licence, that I, the said George Lilley, my exors, adñiors, and assigns, or
such others as I, the said George Lilley, my exors, adñiors, or assigns, should
at any time agree with, and no others, from time to times and at all times
thereafter during the term of years therein expressed, should and lawfully
might make, use, exercise, and vend, within England, Wales, aud the Town
of Berwick-upon-Tweed, and also in all His Majesty's Colonies and Planta-
tions abroad, my Invention of "CERTAIN IMPROVEMENTS IN THE CONSTRUCTION
OF ENGINES OR MACHINERY (TO BE WROUGHT BY STEAM OR OTHER ELASTIC FLUIDS).
APPLICABLE TO THE DRIVING OF MILLS AND OTHER USEFUL PURPOSES;" in which said
Letters Patent there is contained a proviso obliging me, the said George Lilley,
by an instrument in writing under my hand and seal, particularly to describe
and ascertain the nature of my said Invention, and in what manner the same
is to be performed, and to cause the same to be enrolled in His Majesty's High

page_text: Court of Chancery within six calendar months next and immediately after the
date of the said Letters Patent, as in and by the same, reference being there-
unto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
George Lilley, do hereby declare that the nature of my said improvements
is as follows, that is to say:--
I compress atmospheric air or other elastic fluids by means of mechanical
force in a vessel, or in vessels of a low or moderate temprature, and after-
wards let the same pass into a tube or into tubes, vessel or vessels, of a much
higher temprature, and after acting on a piston or pistons permit it to escape
into the atmosphere, by which means the expence of fuel will not only be very
much lessened, but I am enabled to construct engines which will take up much
less room than steam engines in their usual form, be considerably lighter also,
and which may be worked in some situations where the common steam engine
cannot, for want of a necessary supply of water; and when engines are
constructed with some parts of my said improvements, and wrought by steam,
the power will be delivered more uniformly, which admits of the fly wheel
being made lighter than with the usual way of constructing steam engines, the
pistons, &c., of the working cylinders will be formed so as to lessen the
friction, and by the means of a fluid prevent the possibility of steam passing
between them and the cylinders. The valves will be rotary, and so constructed
also, as by the intervention of a fluid, to obviate the possibility of steam passing
through them during the time it should be cut off from the cylinder, and the
whole will take up less room than steam engines of the common construction.
And the manner in which my said Improvements are to be performed is
particularly described and ascertained in and by the Drawings hereunto
annexed, and the following description thereof (that is to say):-
Figure 1st is a representation of an engine with my said improvements, as
wrought by the agency of atmospheric air. A, a reservoir placed in or over
a furnace in such a manner that the flame or heat may circulate freely round
all sides of it, and is here for the sake of description drawn in section, or with
the front part of it taken off, and is about eight times the capacity of the
motive or working cylinder. This reservoir is enclosed in a strong case B, of
cast iron or other materials, between which and the reservoir, in the space b,
is interposed a non-elastic fluid, in order to prevent the explosion of the reser-
voir A, when it has great elastic force in it, by means of using a pressure upon
the said fluid, which fluid at the same time distributes the heat uniformly; (but
as fluids have already been so used in some steam engines, that is, for the purpose
of heating steam vessels uniformly), I do not here claim the use of fluids exclu-

page_text: sively for that purpose, but only as united with pressure, by means of an air
box or small cylinder with a moving piston and weight, for the purpose of pre-
venting the explosion of reservoirs, boilers, air vessels, or steam vessels, in air
engines or steam engines. C, the small reservoir or air box, which is made to
screw off and leave an opening to pour the fluid in at, which passes through
the pipe e, and fills the whole space b, between the reservoir A and its outer
case B, and also the pipe e, up to where the air box is made to screw on at d.
The fluid should be non-elastic, as mercury, lead, bismuth and lead, or any of the
metals in their fluid state, which will remain so under the temprature used in
the reservoir A, or, in some cases, oil, wax, fat of animals, water, or other sub-
stance which will remain fluid and not change into gas under the temperature
required in the reservoir A. and the pressure of the air in the air box C. After
the space b and pipe e are so filled I screw on the air box C, and apply a com-
mon syringe to the pipe (e, e,) provided for that purpose with a stop cock, and
force a quantity of air or steam, or any clastic fluid (but in all cases air or any
permanently elastic fluid is preferable), until the elastic pressure of the air in
the air box C is equal to or superior to the elastic pressure of the heated air
in the reservoir A. As the fluid will not contract and expand in the same
proportion as the cases between which it is placed will by different degrees
of temperature, the fluid will rise and fall in the pipe e according to the
difference of their expansibility, and the air in the air box C need not
occupy more space than to allow of that rising and falling, without having its
capacity materially altered; allowance for this variation should be made in
the cylinder if a piston and weight be used. The utility of this improvement
will be obvious, for, as the surface of the fluid in the pipe e has a pressure on
it equal to or more than equal to the elastic force in the reservoir A, it is
evident that the interior case or reservoir A can have no tendency to explode.
The top part of the reservoir A is never exposed to the immediate action of
the fire, and can be made of sufficient strength, without much increasing the
weight of metal, or enclosed also in the fluid if required. The reservoir should
be made of wrought iron or copper, and proved to bear several times the pres-
sure intended to be used in it, which is regulated by the safety valve e. If.
then, the case B should be burnt through or broken, the unclastic fluid would
fall into the furnace without doing any mischief, and shew that the outer case
wanted replacing. I also use the same means for preventing explosion of the
boilers of high-pressure steam engines. And I sometimes make several cases
with small spaces between them, which spaces must be totally seperate: to each
space I adapt a small air box as above described, in order to divide the ex-
pansive force required in the reservoir or boiler or other vessel or vessels used

page_text: in air engines or steam engines, among a number of cases, and lessen the risk
of explosion as much as may be desired; for instance, if I use three cases over
a boiler in which 40 lbs. per inch expansive force is required, then I have three
spaces for fluid, to each of which I apply an air box, &c., as above de-
scribed, and into the first, or that air box which communicates with the
space next the boiler, I force air, (with or without fluid,) into the space till
the pressure in it, and consequently on the boiler, be 30 lbs. per inch, into the
second till it be 20 lbs. per inch, and into the third (or that air box which com-
municates with the space next the fire, which space should be filled with a non-
elastic fluid) I force air till it bears a pressure of 10 lbs. per inch; so that the
pressure of 40 lbs. per inch of explosive force in the boiler is divided among
the cases and boiler, and no one sustains a difference of pressure of more than
10 lbs. per inch between its inner and outer surfaces. It will be seen that if
the number of cases be increased, the tendancy to explode will be decreased in
the same proportion; such reservoir or boiler, and cases, if made of copper,
need therefore only be very thin, as the fire never acts immediately on any but
the outer case. D, a cistern, which contains a double acting forcing or com-
pressing pump (which I call the compresser) to be herein-after described, from
which the reservoir A is supplied with cold air or other clastic fluid of a low
or moderate temperature when the engine is working. This cistern should be
made no larger than to allow water to rise freely from the bottom of it, round
the outsides of the compresser, so that as much as possible of the water which
is forced in at the bottom of the cistern may touch the compresser, and rising
round it be carried off at the top of the cistern. E a cold water pump, which
raises a small quantity of water (where cold water can be readily obtained and
is desirable) every ascent of its piston, and forces it into the cistern D, below
the compressor, to keep the compresser as cold as possible. When cold water
cannot be had readily I cause a current of cold air to circulate round the com-
presser, by means of a pair of bellows or pump worked by the engine itself.
F, a pipe with its branches 1, 2, conveys the cold air or other elastic fluid of a
low or moderate temperature from the compresser to the hot reservoir A.
G, a hot cylinder, with an air-tight piston moving freely in it, on the two sides
of which piston the hot air is made to act alternately, the same as steam in
the working cylinder of a steam engine. This cylinder I call the motive
cylinder, and its piston the motive piston. The motive cylinder is placed in an
outer case H, between which and the cylinder I cause the smoke and hot air
of the furnace to circulate, by carrying the flue of the furnace two or three
times round the cylinder, (in a similar way to the partition walls seen crossing
the reservoir A,) and afterwards carrying it off near the top of the cylinder G.

page_text: This cylinder, with its valves, &c., is further described by Nos. 1 and 3. K, K,
a
pipe which conveys the heated air or clastic fluid from the inside of the
reservoir A, through heated pipes or passages (as will be herein-after described)
into the top of the valve case M, at L. M the valve case, in which is a
revolving double pipe, formed with proper orifices for admitting and educing.
the air into and from the motive cylinder, which is further described by No. 1.
O, the pipe which conveys the heated air and smoke of the furnace into the
chimney, which pipe should be directed downwards a little way, to cause the
air and smoke to part with as much of their heat as possible before escaping
into the chimney. P, a rod, connected at its top with the lever of a damper
in the pipe O, which turns its edge or its broad side to open or close the
flue of the furnace as the rod P falls or rises. It is also connected at its
bottom with a float, as will be seen by the dots in the gauge pipe 7. This
pipe is connected with an air-tight metallic vessel, which is fastened to the
case of the motive cylinder, the top part of which contains a small quantity.
of air, over the surface of as much mercury as will fill the pipe 7, made large
euough to hold an iron float that is heavy enough to open and shut the dam-
per, by being allowed to fall and rise as the mercury falls and rises in the
pipe 7, by the expansion of the air in the metallic vessel. The rod P is gra-
duated so as to shew the degrees of temprature of the motive cylinder. R, a
regulating valve which is connected with a governor or revolving pendulum, for
regulating the velocity of the engine, the same as in steam engines. S, back
of a gauge, which shews the elastic pressure of the air in the reservoir A.
T small charger or compressing syringe, which is applied for the purpose of
forcing the air into the reservoir A, by hand or otherwise, when the engine is
to be started. U, a pump for regulating the quantity of fluid in the motive
piston and valves. V, a small stopcock, to prevent the hot air of the reser-
voir A communicating with the cold compresser when the engine is at rest.
W, a stopcock for cutting off the communication between the reservoir A and
the motive cylinder G, and for starting or stopping the engine. X, the cross
rod of a parallel frame, connected to the beam and kept plumb in the usual
way, to which cross rod the connecting rods of both the motive and compresser
pistons are fixed. This frame spans the motive cylinder and case and works on
opposite sides of them; the front rod of it is left out in the Drawing, but part of
its back rod is seen above at Y. Z, the furnace, in or over which I place the
reservoir A, in order to increase the clastic force of the air or other clastic
fluids (when other elastic fluids are used) by heat, as it passes thro' the
reservoir to the motive cylinder in which it acts on the motive piston, and puts
the whole of the machinery into action.

page_text: No. 1 is a section of the motive cylinder with its piston, valves, &c., by which
I explain my improvements of pistons and valves. I make my pistons in two
parts, a top and a bottom, and bolt them firmly together so as to leave room
for a small quantity of fluid to be interposed between them. A is the motive
piston, a its top part or plate, which is cast with a rim on it that reaches nearly
to the bottom part or plate b, and this rim I make one fourth or one half of
an inch less in diameter than the inside of the cylinder, so as to leave one
eighth or one fourth of an inch for the fluid all round the rim between the
inside of the cylinder and the outside of the rim. This top part has a hole
through it, c, for the air and fluid to pass through into the space between the
top plate a and the bottom plate b, and on the upper side of the top plate a
I make a channel completely round the centre of the piston, and at the same
distance from the centre as the hole c, so that all the fluid which falls on the
top of the piston will readily find its course to the hole c to keep up the proper
quantity of fluid between the plates. The plate a to which the rim is cast is
made so as to fit easily in the cylinder, and so is the lower part or plate b. On
this plate b, which has a hole through it at d, I cast a small pipe which reaches
nearly to the under side of the top plate a so as to allow a globular or double
conical clack e to have a little play between the top of the pipe and the under
side of the top plate for the air and fluid to pass through on to the surface of
the fluid between the two plates. This globular clack is made to fit air-tight
into the hole or seat c in the underside of the top plate a, and also into the top
of the pipe d, and form a double valve so as to prevent the air passing it from
either side of the piston to the other; it is balanced by a small rod and weight
fixed on a centre, as will be seen by the Drawing, so that the least difference
of pressure on either side of the clack will close it the contrary way. Instead of
nearly filling all the space between the top plate a and the bottom plate b,
inside the rim as above named, with fluid, I sometimes make a solid round
piece of wood or metal, with a hole through it to admit the pipe d, and so thick
as not to reach quite so high as the top of the pipe d, and place it firmly
between the top and bottom plates inside the rim as in the Drawing, but such
piece of wood or metal must not be made to fill the inside of the rim nearer
than what would allow of more fluid between the inside of the rim and wood
or metal so placed than would be forced past the sides of the piston in two
strokes of the engine, for the space between the top and bottom plates is
supplied with fluid every down stroke of the engine only. The fluid may be
mercury, lead, bismuth and lead, or any of the metals or other substance, which
will remain in a state of fusion and not change into gas under the temperature
and pressure intended to be used, as wax, the fat of animals, oils, &c., whichso-

page_text: ever may best suit the elastic fluid used for driving the engine; and to prevent
too much fluid passing between the inside of the cylinder and the piston, I
introduce thin metallic rings into a groove in the edges of the top and bottom
plates of the piston f, f, which rings fit exactly into the grooves, and are made
in seperate pieces with a slight spring, or with slight springs, or by letting the
unelastic fluid communicate with the interior of the metallic rings to keep them
pressed to the cylinder. The manner of supplying the piston as well as the
valves with the necessary quantity of fluid is herein-after described. We will
now suppose such a quantity of air or steam to be admitted on to the top of
the piston as will cause a great difference of pressure between the top and
under sides of the piston. It is evident from what has been said that if the
whole of the space between the top and bottom parts of the piston be fill'd
with fluid, the superior pressure on the top side of the clack e will instantly
force it into its other seat at the top of the pipe d, so that no air or steam can
possibly pass to the under side of the piston till it has first forced all the fluid
before it; but this cannot be done during two strokes of the engine, for the top
and bottom rings f, f, fit so nearly as to admit but very little of a non-elastic
fluid to pass them, and the next time the piston comes to the top of the cylinder
it is supplied with a fresh quantity of such fluid. The same may be said if air
or steam be admitted to the under side of the piston; it would, in that case,
instantly close the clack e upwards, and the pressure on the surface of the fluid
within the rim would be the same as before; no air or steam can therefore
possibly pass up between the cylinder and piston, for the pressure on the surface
of the fluid inside of the rim, and consequently all round the piston, is equal to
the pressure of the air or steam under the piston; but the gravity of the fluid
gives it a tendancy to fall; therefore, as the pressure of the air or steam is equal
both ways, the fluid will fall down the sides of the piston, and until all the fluid
inside the rim is first forced under that rim, no air or steam can possibly pass
upwards. If any fluid pass by the upper metallic ring f, it will run into the
channel above described, and the next time the clack e closes downwards it will
fall into the piston again. The valve case M (seen also at M, Fig. 1), incloses
a pipe g, g, which reaches a certain distance above the top orifice h,
where the air passes to and from the top side of the piston A, and also a
certain distance below the bottom orifice i, where the air. passes to and
from the bottom side of the piston A. This pipe is turned perfectly cylin-
drical a certain distance from each end so as to fit close into its hollow
circular seat k, k, cast on with the cylinder and made to project further
than the flanch to which the valve case is bolted, seen more distinctly at k,
No. 3, which is a plan of the top of the motive cylinder, valve, pipe, and its

page_text: packings. Through the sides of the pipe g, g, where it is turned, I make four
orifices or opening 1, 2, 3, 4, two at each end, the top ones of which are seen
more distinctly at 1, 2, in No. 3.
1 is the top admission orifice, and 2 the top
eduction orifice; the bottom admission and eduction orifices 3, 4, No. 1, are
made in the same way; that which admits the air into the cylinder at the
bottom 3 must be made on the opposite side to that which admits the air into
the cylinder at the top 1, and that which educes the air from the bottom of the
cylinder 4 must be made opposite to that which educes the air from the cylinder
at the top 2; this pipe g, g, has another pipe l, within it, which is open at its top
at m, but closed at its bottom at n, so as to allow of no communication with
the top of the valve case and motive cylinder but through the orifice 3 into
the bottom of the cylinder, when the other side of the pipe g, g, is turned to
the cylinder, and consequently the pipe 1, for the pipe is cast or brazed to the
pipe g, g, all round the bottom admission orifice 3, and also all round the top
admission orifice 1, and all round the pipe near its top, except where this
orifice opens into the top of the valve case for admitting the air and the
fluid into the top of the cylinder. I envelope the whole of the pipe g, g
and its packings in fluid, and constantly keep the space between it and the valve
case full as high as the top of the outer pipe g, g, which fluid is represented by
the yellow part in No. 1. This fluid I prevent passing through any of the
orifices except the top admission orifice 1, by placing packings of metal round
those parts of the pipe through which the orifices are made. These packings
are in several pieces of the same depth as the valve seats k, k, and in such a
form as to follow up to the pipe g, g, as they wear away. Two air-tight
screws o,'o, are tapped through the case M so as to screw casily against the
outer brass of each packing, and keep them to their proper places. The outer pipe
g, g, is made large enough to allow room between it and the inner pipe l, and
also all the way down to the opening 5, for the air from the eduction valves to
pass freely off into the case 6, from which it is carried out of the building (as
seen by the dotted pipe in Fig. 1st). The form of the packings may be under-
stood by inspecting the red parts in Nos. 1 and 3. The pipe g, g, is continued
downwards thro' a stuffing box (properly packed to keep the fluid from escaping),
and becomes solid below the orifice 5, after which it passes into a hollow shaft
p, (on which a cogged wheel is staked), turning, in its chair, which prevents it
rising or falling; the solid part of the pipe g, g, has a screw tapped on the
outside of it, r, fitting into a nut s, which has a hole to admit a pin passing
through the nut into a circular groove turned on the outside of the hollow
shaft p, so as to form a swivel, and allow the pipe g, g, to rise or fall by turning
the nuts; at the same time a cotter passing through the wheel shaft and a long

page_text: १
slit in the solid part of the pipe g, g, prevents the pipe g, g, and wheel
altering their relative position as to the orifices of the pipe, so that the pipe
may be raised or lowered so as to adapt the size of the valves to the velocity
required in the engine. From what has been said it will be easily seen that as
the wheel q is connected with the fly-wheel, beam, &c., which are here used in
their common form, the valves, which make one revolution during two strokes of
the piston, must, when once properly formed and fixed, always open with the
same relative position of the piston. The pipes and g, g, instead of being
made in one, might be so made as to admit the air or other clastic fluids in one
valve case, and educe it or them in another valve case, which may in some
circumstances be an advantage. The valve case M and the motive piston A
are supplied with a proper quantity of fluid by the pump U, Fig. 1, which
communicates with the pipe and valves seen at No. 1, where one branch opens
into the reservoir and inverted stuffing box w, w, and the other branch into the
bottom of the valve case M. Suppose the motive piston A at the top of the
cylinder, and that the piston is full of fluid, as well as the pump U, (Fig. 1
with its pipes,) and the valve case M as high as the top of the pipe l, then the
air rushing upon the top of themotive piston A forces it down and closes the
clack e downwards, at the same time the fluid which was over the top of the
pipe g,g, and prevented falling down the pipe e by its projecting a little higher
than the pipe g, g, (as in the Drawing) rushes on to the top of the piston and
falls into it through the valve now open; what escapes past the sides of the
piston falls into the reservoir w, while the piston of the pump U (Fig. 1) is
forcing the fluid through the valve. a into the bottom of the valve case M,
which will raise the fluid contained therein to the same elevation as before the
piston A started; when the motive piston ascends, the clack e closes upwards,
and all the fluid inside of the rim above the top of the pipe d falls into the reser-
voir w, and (together with what passed the sides of the piston), is drawn from
it again through the valve y by the pump U (Fig. 1), when the piston ascends;
but so soon as the piston begins to descend, the vale y closes, and the fluid is
forced past the valve as before, keeping the whole properly filled. The
handle by which the stopcock 12 is turned is connected with those of V and
W, (Fig. 1) (tho' not drawn so), so that when the engine is stopped this cock
is sure to be opened, and if any fluid fall out of the piston it will run off into
the vessel placed under the pipe to receive it; when the engine is set to work
again, what has run off is poured into the funnel 14 at the top of the cylinder.
The orifices in the pipe 9, 9, and the passages h and i, may be made as to
allow air or steam to pass into the motive cylinder during the whole length of
each stroke of the piston; or so as to cut off the air or steam when the piston

page_text: has got to one half or any other division of the length of each stroke of the
piston. If they be required both to admit and educe the air or steam during
the whole length of the stroke, then the four orifices in the pipe g, g, should
all be equal and cut out one fourth of the circumference of the pipe g,
with one fourth between each, and the orifices h and i the same. If it be
required to admit the air or steam into the cylinder during only one half the
length of each stroke, and to educe it during the whole length, then the
admission orifice should be cut one eighth of the circumference of the pipe g, g,
and the passages into the cylinder should be the same; but the eduction
orifices in the pipe g, g, should in this case be cut three eighths; and in all
cases when the passages into the cylinder h and i are made the same as the
admission orifices in the pipe, the circumference of the two orifices of either
end added together should be equal to half the circumference of the valve
pipe, in order that the eduction valves should be open the whole length of the
strokes; of course the orifices length way of the pipes, and also the diameter
of the pipes land g, g, must be varied according to the required area of the
valves. No. 3 also shews a top view of my method of making the pipe or
passage through which the elastic fluid passes, in order to touch as much
heated metal as possible before entering the inside of the motive cylinder.
The motive cylinder itself is formed of two cases, with longitudinal partitions
between them, leaving spaces between the partitions for the elastic fluid to
pass through. The uncoloured parts show the tops of the passages; there are
19 in the Figure. The partitions are represented by the black and green parts.
Every green part or partition is made so much lower than the black partitions
as to allow an area equal to the white parts or passages, so that when a
metallic ring is fitted air-tight between the inner cylinder 6 and the outer
cylinder or flanch 7, (between which a groove is accurately turned for that
purpose, none of the elastic fluid can escape out of the passage; but after
entering near the bottom of the cylinder it raises up the space 8, goes between
the top of its green partition and the ring and down the passage 9, up 10, down
11, and so on till it reaches at the top 26, through the pipe L, (seen at Fig. 1)
into the top of the valve case. Both ends of the cylinder are formed in the
same way, and the rings project above the flanches, so that the top and bottom
of the cylinder may be fitted air-tight on to them. No. 2 is a section of the
compresser, by which it will be seen that the elastic fluid is compressed and
forced into the reservoir during both the ascent and descent of its piston P.
The admission valves 1 and 2 are balanced so as to open and shut readily by
the pressure of the elastic fluid on them. The valves 3 and 4 allow the com-
pressed elastic fluid to pass into the reservoir, but prevent its return; the

page_text: same as in common condensing or compressing syringes. To the admission
valves 1 and 2 (seen in Fig. 1 by the dotted lines) upon the cistern D), I apply
any well known contrivance that will keep them open during any desired
portion of the stroke of the piston, and allow them to close each stroke when
there is no more elastic fluid remaining before the piston than what may be
required for the temperature of the motive cylinder. In some cases, two or
three small compressers may be applied, and used according to the temprature
and power required in the engine, for the difference of capacity of the motive.
and compresser cylinders must always be proportioned according to the dif-
ference of temprature of the compresser and motive cylinders; or, which is the
same thing, if by the difference of temprature used, the elastic fluid which is
made to drive the engine will expand to 2, 3, 4, 5, 6, or any number of times
the capacity it had in the compresser before the piston of the compressor had
forced it into less compass, and still balance the pressure of the external
atmosphere, then, to receive all the force gained by using the same elastic
fluid with different tempratures, the motive cylinder must be made 2, 3, 4, 5, 6,
or such proportionate number of times more than the compressor. When
any other clastic fluid than atmospheric air is used to drive the engine, the two
admission valves of the compressor should communicate with, or the com-
pressor itself, in most cases, be placed in, the vessel or vessels in which such
other elastic fluid is created, kept at such low or moderate temprature as
before named. In order to keep the reservoir or motive cylinder, or either of
them, of a uniform temperature above the boiling point, I sometimes introduce
water into the space or spaces between it or them, and their case or cases, as
above described, for preventing their explosion; and in place of the air box, I
apply an Edelcrantz's safety valve beneath, and to the piston of which I fasten
a rod with a float on its bottom, so that when the temperature of the water is
above the boiling point, there will always be steam beneath the piston; then
the temperature of the enclosed vessel will be according to the weight placed
on the piston, for if the valve be sufficiently large, the steam raising the piston
will escape, and carry off the superfluous heat. Any well known contrivance
may be applied for keeping a regular supply of water in the case.
Fig. 2, Nos. 1 and 2, are seperate views of my improved method of
changing reciprocating into rotary motion, or rotary into reciprocating motion,
which I in some cases apply to air engines or steam engines, for transferring
the force of their reciprocating pistons to revolving shafts. In No. 2 (Fig. 2),
A is a strong rim or projection, cast on a solid or hollow cast iron drum or
barrel B, which is the supporter of the rim A. This drum or barrel B is
staked on a strong axis or revolving shaft C, passing through it lengthwise, on

page_text: which the drum and rim revolve. On each side of the rim A (which projects
from the drum B equally all round) is fixed a friction wheel D, E, whose cir-
cumferences apply closely to the opposite sides of the rim A. The centres or
chairs of the wheels (fixed in the top of the connecting rod of the piston P,
as seen at Fig. 2) follow up, as they wear away, in the usual manner, to
readily adapt the wheels to the size of the rim. Any proper contrivance or
parallel movement may be applied to keep the piston rod parallel to the axis
of the drum, as that seen by the rods h, h, h, h, in Fig. 2, and, also at the top
view No. 3, in which it is shewn by the dotted lines that the axis of the
parallel rods point in a line nearly perpendicular to the opposite sides of the
angle which the circumferences of the wheels form; the rods are fixed in this
form to keep the wheels up to the drum.
To shew how this method will change rotary into reciprocating motion, we
will suppose the drum B, and rim A, to be fixed on their axis C, C, so that the
axis will not rise or lower, but only turn easily in its chairs; and that the
piston rod P can only reciprocate in a line parallel to the axis of the drum B.
If then I turn the drum and rim round in the direction the arrow points, the
rim at 1 will press upon the under wheel D, and force down the piston rod till
the rim has made half a revolution, for then the top wheel has got to the
lowest part of the top side of the rim, and prevents the piston rod going any
further down. If I still continue to turn the rim forward in the same
direction, the top side of the rim presses the under side of the top wheel, and
forces the piston rod up, till the wheel gets on to the highest part of the rim,
and so on. When I apply this improvement for changing reciprocating into
rotary motion, I stake the fly wheel on the shaft C, to carry the rim forward
when the rod is at the two points where the piston returns; and then the
wheels D, E, pressing upon the opposite sides of the rim (to which the rim
before pressed them), force the rim, and consequently the fly wheel, the same
way round as before. When the wheels D, E, span any part of the rim A,
except at the ends or points H, H, (one of which is seen at H, Fig. 2, the
fly wheel, may be made to go either way round, by forcing the piston and its
rod accordingly. The top and bottom of the rim A are made round, in order
to prevent any sudden stroke or backlash when the motion of the piston rod is
returned; and it is also made broader at the ends H, H, than in any other
part of the rim, as will be seen by comparing the ends of the rim scen at H,
with the part of it seen at J, No. 1, so that both wheels may clasp or nearly
clasp the rim all round. The form of the top of the piston rod, where the
wheels are placed, will be seen by inspection. The rim should be so formed
on the drum as to make an angle of forty-five degrees with the piston rod as

page_text: it passes between the wheels (except where it is made round at the end), in
order that the fly wheel may go round with equal power either way. The
advantages of using this method are these:-If the force delivered to the
piston be uniform, it is transferred to the revolving or fly shaft with uniformity
of power (except at the ends), as will be evident when it is considered that
the wheels D, E, always act at the same distance from the axis of the drum
on which the rim is placed. The fly wheel need only be comparitively light,
for the wheels D, E, act with uniformity of power till they come to the round
part H, which may be varied from a point to any size. As the power may be
delivered in this way without the intervention of the crank beam, &c., the
space occupied by an engine with these improvements will be comparatively
small. The power obtained by compressing elastic fluids in a certain tempe-
rature, and afterwards allowing them to act in a higher temperature, may be
made obvious; thus, suppose the clastic fluid to be atmospheric air, and that a
tube contains twelve cubic inches with its natural temperature and elasticty,
it will require a certain force to compress this air into two cubic inches (say a
weight of 13 lbs. falling one foot), but, leaving out the consideration of friction,
the clasticity of the air itself (compressed into this compass) would, in the:
same temperature, raise the same weight to the height whence it fell. If then
I place the tube and air in a temperature which would double the elasticity
which the air had in its natural temperature, and then let it expand till it had
the same clastic force it had before I compressed it in its natural state, it will
give me back a force which would raise 26 lbs. a foot high, and have a dis-
posable force of 13 lbs. through the same height; and the same may be said
of any other elastic fluid. The apparatus described in Fig. 2, No. 1 & 2, I
only claim in combination with my aforesaid machinery, and not as a seperate
Invention. To set the engine to work, I make a fire in the furnace, and close
the cocks V and W, and then force so much atmospheric air or other elastic
fluid into the reservoir by means of the charger T, as will, when it has received
the intended temperature, act on the motive piston with sufficient force to
drive the machinery; and when the reservoir and the motive cylinder have
acquired their proper temperature, I open the cocks V & W, the elastic fluid
instantly rushes from the reservoir into the motive cylinder, and, driving the
motive piston forward, forces an adequate supply of the elastic fluid in a lower
temperature from the compresser into the reservoir, while that last used escapes
into the atmosphere. The disposable force is thus accumulated in the fly
wheel, and may be used as required.
And the more fully to ascertain in what my said improvements consist, I
declare that I do not hereby mean to claim as my Invention any of the several.

page_text: parts included in this description and Drawing which may have been in use
before, but only such parts of the same as are new, when applied with steam
or other elastic fluids (as herein described) for the driving of machinery.
In witness whereof, I, the said George Lilley, have hereunto set my hand
and seal, this Nineteenth day of May, in the year our of Lord One
thousand eight hundred and twenty.
Inrolled the Twenty-third day of May, in the year of our Lord One
thousand eight hundred and twenty.