IMPROVEMENTS IN OBTAIN- ING AND APPLYING MOTIVE POWER
Year: 1852

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
HYATT, of Old Street Road, in the County of Middlesex, Engineer, send
greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Seventeenth day of
April, in the fifteenth year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said William Hyatt, Her especial
license, full power, sole privilege and authority, that I, the said William
Hyatt, my exors, adñiors, and assigns, and such others as I, the said William
Hyatt, my exors, admors, or assigns, should at any time agree with, and
no others, from time to time and at all times during the term of years therein
expressed, should and lawfully might make, use, exercise, and vend, within
England, Wales, and the Town of Berwick-upon-Tweed, in the Islands of
Jersey, Guernsey, Alderney, Sark, and Man, and in all Her Majesty's
Colonies and Plantations abroad, my Invention of "IMPROVEMENTS IN OBTAIN-
ING AND APPLYING MOTIVE POWER;" in which said Letters Patent is contained
a proviso, requiring that I, the said William Hyatt, by an instrument in
writing under my hand and soal, particularly describe and ascertain the
nature of my said Invention, and in what manner the same is to be performed,

page_text: and shall cause the same to be enrolled 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.
NOW KNOW YE, that in compliance with the said proviso, I, the said
William Hyatt, do hereby declare the nature of my Invention, and in
what manner the same is to be performed, to be particularly described and
ascertained in and by this present instrument in writing as follows, reference
being had unto the Drawings hereunto attached, and to the letters and figures
marked thereon, that is to say:-
My said Invention relates,-..
First, to an improved rotatory engine having a cylinder bored elliptically or
with a differential curve, and so contrived that its effect shall be uniform, or
nearly so, throughout each entire revolution, whilst no slide or other working
valves are required.
Second, to an improved arrangement of steam boiler or generator wherein
an internal steam chamber is used, as well to economise fuel as to save time
in getting up the steam.
Third, to an improved. arrangement of reciprocating steam engine fitted to
work with two or more pistons in one cylinder, so as to effect great economy
of fuel and secure superior efficiency of action.
Figure 1, on Sheet 1 of my Drawings, is a side or longitudinal elevation of
one modification of my improved rotatory steam engine. Figure 2 is a
corresponding end elevation of the same at right angles to Figure 1, one of the
end covers being removed from the cylinder to exhibit the internal mechanism;
and Figure 3 is a complete plan of the engine. The short steam cylinder A,
open at each end and fitted with two end covers, is placed with its axis
horizontal upon the base plate B, being bolted down thereon by four lugs or
projecting eyes C. The steam cylinder is bored elliptically, the extent of the
ellipticity or the deviation from the true circle being only required to be
extremely slight. The horizontal piston rod or main engine shaft D is passed
eccentrically through the cylinder, and in the vertical line of the minor or
conjugate axis of the ellipse. The rotatory piston E is composed of cast-iron,.
and suitably fitted with packing pieces, and slotted transversely at F to fit to
the piston rod, the transverse section of which at that part is rectangular. The,
slot F is for the purpose of allowing of the self-adjustment of the piston during
its revolution in working, by sliding laterally over the squared shaft or rod D.
The packing of the piston, which packing is at the same time a portion of the
working steam pressure surface, consists of two metallic strips or ribs G of the
length of the cylinder, the outer projecting surfaces of such ribs being rounded

page_text: or semicircular in transverse section, whilst their inner flat sides are fitted into
shallow grooves or recesses H, formed diametrically opposite to each other
along the piston and in its axial line. The actual working packings are strips
of metal I, fitted on their inner sides to the external rounded surfaces of the
pieces G, whilst their outer surfaces bear against the interior of the cylinder.
These outer rubbing surfaces of the packings I are considerably rounded in
transverse section, the radius of curvature being slightly less than that of the
quickest curve of the cylinder's bore, so that the packings may work round
the sharpest elliptic curves with facility, and helical or other springs are set in
behind the packing pieces to admit of free adjustment during working.
Another form may be given to the packing parts G and I, that is, the piece I
may be made convex, the centre of the convexity being in the outside, while
the
part
G. will be concave so as to fit the convex piece I.. In this case, as
the centre of the piece I is always in the circumference of the ellipse, and at
the same time in the end of the straight line running through the centre of
the sliding piston, it follows that this line must always be exactly the same
length, however obliquely the pieces 1 are applied to the sides of the ellipse.
The flat end packing for keeping the piston, steam tight at its two ends is
composed in each case of the brass ring J let into the end of the piston, and
having the two projections K upon it passing through slots in the ends of the
strips G, thus forming a simple and effective end packing. A small brass
plate K' is let into the ends of the strips I to complete the end packing.
The piston rod is supported in a stuffing box L on the outside of each cylinder
end cover, and the engine in the present case being a single one the shaft has
a fly wheel M keyed upon it, the heavy rim of the wheel being cast hollow at
certain parts to balance the overhang of the piston. That end of the shaft
which passes away to the machinery to be driven is supported in a pedestal N
bolted down on a base plate; this bearing, in conjunction with the pair of
stuffing boxes, being the only bearings requisite when one end only of the
shaft is used. No working valves at all are required, the steam being admitted
in à constant stream by either of the two opposite ports O, the only variation of
the current being when the slot F is horizontal, this being the dead centre of
the engine, and both ports are then closed. Or by another slight modification the
steam and exhaust ports may be made to extend a long way round the cylinder,
in order that the engine may have no dead point, the steam being admitted
to the back of the revolving arm or piston blade before it is entirely shut off'
from the front side. For reversing, an ordinary three-way cock answers every.
purpose, one cock being set on each side of the cylinder, and put in connection

page_text: by means of two double-branched pipes, so that either side may be made
the steam ingress side. It will be clear to the practical man that the steam
acts equally well in both directions of revolution, the effective pressure being
that upon the overhang or eccentricity of the piston, which is constantly vary-
ing in effective area throughout the revolution, the piston being indeed a
direct acting crank lever for turning the shaft. For lubrication, an oil
reservoir P is set on the top of the cylinder, a stopcock Q being fitted beneath
it to command the oleaginous flow through the pipes R, which have each two
branches for lubricating both the bored portion of the cylinder and the flat
end cover surfaces. In engines of this class, the effective diameter of the
piston or the distance measured diametrically across between the two exterior
bearing surfaces I must coincide exactly with the minor axial length of the
elliptical bore; this is effected by helical or other springs, and as the piston
revolves in the cylinder it follows, from the known property of ellipses, which
differ but slightly from circles, that the piston will always exactly fill up the
bore at all positions, the distance from the centre of the piston rod to the
bottom of the cylinder being one third of the conjugate diameter of the ellipse;
and I would remark, that an elliptical bore is not essentially necessary in such
engines, as other differentially curved bores may be used with equal effect, the
only essential requisite being that an eccentric shaft or piston rod be so
applied that the piston shall accurately fill up the cylinder at all parts of the
revolution by means of suitable fittings and springs, whilst the curve of the
bore is so regular as not to interfere with the easy motion of the revolving
piston therein.
Such an engine is in addition suitable for use as a pump or
blower for applying motive power in the transmission of fluid or aeriform
bodies. It will be obvious to the practical man that a simple modification of the
above engine is applicable to locomotive engines, in which case two cylinders
may be employed, one on each driving axle, the axles themselves forming the
piston rods of the engine, the pistons being set at right angles to each other
so as to overcome the dead centres. The two driving axles must be coupled
by the coupling rods in the ordinary manner. Figure 4, on the same Sheet
of Drawings, is a transverse vertical section of one form of my improved boiler
or steam generator, with its internal steam chamber. In the example herein
given, the boiler A is either a sphere or cylindrical in transverse section, or any
other shape, and is heated entirely from beneath or by external bottom and side
flues. In its interior is placed the steam chamber B, the bottom of which
is curved to correspond to the curvature of the boiler, whilst its top is very
flatly convex, the depth of water over the top being the same as that included

page_text: between the lower side of the receiver B and the boiler. As the steam is
generated in the usual manner it flows off from the upper side of the boiler
shell through the pipe C, passing away as required by the side branch D.
But in addition to this disposal of the steam, a portion of it passes through a
side aperture D' into the vertical pipe E, opening at its lower end into the top
of the steam receiver B. The bottom end of this pipe E is bolted over an
aperture in the receiver top, whilst the upper end passes up through a stuffing box
in the main external branch C, and its bore is filled up by a blank flange.
The water feed pipe G passes down through the centre of this pipe E and
through the steam chamber B, beneath which it opens into the body of the
boiler at the hottest part of the latter. The steam chamber is fitted with an
upper and a lower manhole H for facilitating repairs, the most convenient
plan for effecting which is to elevate the entire chamber, with its pipe E, by
any convenient purchase. The stopcock I is for the purpose of enabling the
attendant to blow off the water of condensation and steam from the steam
reservoir, the water passing up the small pipe J and out by the cylindrical
aperture in the plug of the cock. By making a slot down one side of the
plug, it may also be employed as a steam blow-off valve, the steam passing
out through the larger pipe encircling the pipe J. A cock of similar con-
struction is fitted at K to serve as a water guage and blow-off cock. The
steam reservoir B is made sufficiently large to displace one half the quantity
of water which it would otherwise be necessary to keep boiling, so that
thus I am enabled to keep a quantity of hot steam in the centre of the
boiler, and displace the great bulk of water which as commonly used is
of no value.
Figure 1, on Sheet 2 of my Drawings, is an end elevation of my improved
direct acting steam engine, looking on the valve chest side. Figure 2 is a
corresponding side elevation of the engine. Figure 3 is a vertical section
of the steam cylinder and valve chest, with the four pistons as they would be
when the cranks were on one dead centre; and Figure 4 is a similar section
shewing the pistons in the positions they take when the cranks are on the
opposite centre. In this engine the steam is supplied from the valve chest A,
which is cast on the side of the long vertical cylinder B, bolted to the top
of the four rectangularly disposed columns C. The cylinder is cast with five
steam ports D, E, F, G, and H, a corresponding number of exhaust ports being
formed in the face of the slide I, which slide is a long tubular piece closed at
the top, and in communication at the bottom with the exhaust pipe J by means
of the wide port K. It is worked from the spindle L passing through the

page_text: stuffing box M on the top of the top of the valve chest, and immediately above
which is a cross head N, having a pair of side rods O descending to a
corresponding cross tail P. To the centre of this cross tail is screwed a
short rod Q, entered through a fixed guide R bolted to the supporting
columns. The lower free end of this rod is jointed to the lever S keyed on
the centre of the rocking shaft T, working in fixed end bearings (bolted to the
columns), and actuated by an eccentric T' on the crank shaft U, the rod V
from this eccentric being passed upwards at an angle to the lever W. The
shaft U has two double cranks X formed upon it, and also on its centre part
a spur wheel Y, in gear with a counterpart wheel Z keyed upon the upper or
secondary driving shaft a, directly above and parallel with the crank shaft.
This shaft has also a pair of double cranks a¹ upon it, precisely the same as
the cranks X beneath, and is driven by the two upper pistons b, c, in the
steam cylinder, whilst the lower pair of pistons d, e, similarly give motion to
the fly-wheel shaft U. The upper pair of pistons work through the top of the
steam cylinder, whilst the lower pair are arranged to work through the
cylinder bottom. The rod 61 of the piston 6 is tubular, to allow the solid
rod d¹ of the piston c to work through it, the stuffing box for the tubular rod
being of course upon the cylinder cover, whilst that for the solid rod is in the
upper end of the tubular one. Similarly the solid rod c¹ of the piston d works
through the tubular rod e¹ of the piston e beneath. These details are shewn
clearly in Figure I, the hollow rod 6' being terminated by a cross head f, into
which is screwed the gland or stuffing box cap g.
At each end of the cross
head f, which is cruciform in Plan, are two eyes to receive the upper ends of
the vertical side rods h, bolted up to form one piece with the cross head, a
similar connection being formed at the bottom with a corresponding cross
tail i, to the centre of which is attached the lower end of the solid piston rod c'.
By this arrangement the pistons 6 and d are geared together to work in the
same directions simultaneously, both rising and both falling at the same time
in the cylinder. In addition to the four eyes already mentioned, the cross
head carries a pair of joint studs, to which are connected the upper ends of
the descending connecting rods j, the lower ends of which pass down to the
pair of double cranks a¹ on the upper shaft a. In this way the combined
action of the pistons b, d, is communicated to the shaft a, so that for every
double stroke of the pistons b, d, the crank shaft a makes one revolution.
The motion of the remaining pair of pistons c, e, is transmitted to the main
crank shaft U through the outside pair of rods K, which have open frames at
their lower ends' to enable them to pass over the upper shaft a, the brasses!

page_text: for the pins of the double cranks X being attached to the bottoms of the frame
pieces. The upper ends of these connecting rods K are jointed to the ends of
the main cross head m fast on the upper end of the upper solid piston rod d¹ of
the piston c, and the same cross head m also carries the intermediate pair of
connecting rods n passing down to the opposite ends of the corresponding
cross tail o attached to the lower tubular piston rod e³ of the piston e. By this
means the second pair of pistons c¹, e, are made to actuate the main shaft,
both pistons moving simultaneously together like the other pair, so that the two
shafts a and U are actuated with equal power, and are combined to work in
concert by the spur wheels Y, Z, the power of the engine being finally taken
off the main shaft U. As represented in the detail, Figure 3, the actuating
steam is supposed to be entering the cylinder through the ports D, F, H,
whilst the preceding supply is exhausting through the ports E, G, into the
condenser by the intervention of the hollow of the slide I, the bottom port K,
and pipe J. During this stroke, or the motion of the four pistons from the
position in which I have represented them in Figure 3, the steam entering at
the ports D and H acts between the fixed top and bottom of the cylinder, and
the upper and lower sides of the upper and lower pistons b, e, respectively
bringing one up and the other down, whilst the steam passed in by the central
port F gets in between the two central pistons c, d, and acts on both to push
them asunder. Figure 4 shews the pistons when the cranks are
opposite centre, the action of the steam being confined entirely to the piston
surfaces in each case, that is, the steam passing in by the port E pushes
asunder the pistons b, c, whilst the steam entering by the port G similarly
expands the space between the pistons d, e, and the exhaust is going on
through the ports D, F, H. In this way the steam action in the cylinder is
accurately balanced in all positions of the pistons, the strain of working being
always confined within the limits of the cylinder covers.
Such engines may,
therefore, be effectively worked at very high speeds with a superior effect,
because the steam pressure upon the pistons is conveyed to the crank shaft to
be driven in the most direct manner, all objectionable strain outside the
cylinder being counteracted at the crank shaft by the opposing pull of the two
pairs of pistons.
on the
Having now described and particularly ascertained the nature of my Inven-
tion, and the manner in which the same is or may be used or carried into
effect, I would observe, in conclusion, that I do not confine or restrict myself
to the precise details or arrangements which I have had occasion to describe
or refer to, as many variations may be made therefrom without deviating from
the principles or main features of my Invention; but what I consider to be

page_text: novel and original, and therefore claim as the Invention secured to me by the
herein-before in part recited Letters Patent, is,-
First, the general arrangement and construction of the elliptic or differen-
tially curved cylinder rotatory engine, as herein-before described.
Second, the system or mode of constructing rotatory engines with elliptic or
differentially bored cylinders.
Third, the system or mode of constructing rotatory engines with elliptic or
differentially curved cylinders, wherein the revolving piston shall always exactly
fill up by means of springs, and fit to the working cylinder surface at all
portions of its revolution, as herein-before described.
Fourth, the application and use of rotatory engines with a main shaft set
eccentrically or out of the centre of the minor axial line of the ellipse, or
differentially curved bore of the cylinder.
Fifth, the application of my rotatory engine berein-before described to
locomotive and marine engines in the manner described, either high or low
pressure, and working expansively or not.
Sixth, the application and use in steam boilers or generators of an internal
steam receiver or chamber, for the purpose herein-before described.
Seventh, the system or mode of obtaining a great extent of effective heating
surface in steam boilers or generators by displacing the mass of water ordinarily
retained therein by the insertion of a steam receiver.
Eighth, the system or mode of constructing reciprocating engines with two
or more pistons, as herein-before described.
Ninth, the application and use of two or more pistons working in concert
in one cylinder, as herein-before described.
Tenth, the system or mode of constructing steam engines wherein one
exterior and one intermediate piston in each action are made to work together
simultaneously.
In witness whereof, I have hereunto set my hand and seal, the Sixteenth
day of October. One thousand eight hundred and fifty-two.

page_text: AND BE IT REMEMBERED, that on the Sixteenth day of October, in
the year of our Lord 1852, the aforesaid William Hyatt came before our
said Lady the Queen in Her Chancery, and acknowledged the Specification
aforesaid, and all and every thing 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 Sixteenth day of October, in the year of our Lord One
thousand eight hundred and fifty-two.