CERTAIN IMPROVEMENTS IN THE MODE OF CONSTRUCTING STEAM ENGINES
Year: 1811

page_text: WHEREAS His most Excellent Majesty King George the Third did, by
His Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Second day of November,
in the fifty-second year of His reign, give and grant unto me, CHARLES BRODERIP,
of Great Portland Street, in the Parish of Saint Mary-le-bone, in the County
of Middlesex, Gentleman, my exors, adiñors, and assigns, His Majesty's
special licence, full power, sole privilege and authority, that I, the said Charles
Brodrip, my exors, adiñiors, and assigns, during the term of years therein
expressed, should and lawfully might make, use, exercise, and vend my Inven-
tion of "CERTAIN IMPROVEMENTS IN THE MODE OF CONSTRUCTING STEAM ENGINES,"
within England, Wales, and the Town of Berwick-upon-Tweed, and also in
all His Majestie's Colonies and Plantations abroad; in which said Letters
Patent there is contained a proviso that if I, the said Charles Broderip, should
not particularly describe and ascertain the nature of my said Invention, and
in what manner the same is to be performed, by an instrument in writing
under my hand and seal, and cause the same to be enrolled in His Majesty's
High Court of Chancery within two calendar months next and imme-
diately after the date of the said Letters Patent, that then the said Letters
Patent should cease, determine, and become void, as in and by the said
Letters Patent, reference being thereunto had, will more fully and at large
appear.
NOW, in compliance with the said Letters Patent, I, the said Charles
Broderip, do particularly describe and ascertain the nature of my said Invention,

page_text: and in what manner the same is to be performed, in and by this Instrument in
writing under my hand and seal, as follows, that is to say:-
First, in steam engines which work by the pressure of the atmosphere, com-
monly called atmosphere steam engines, instead of the present cylinder, I use
a cylinder open at both ends, and employ an additional piston to the one already
in use.
These two pistons when at rest nearly meet in the middle of the
cylinder, a space or chamber being there left between them sufficiently large
to allow the steam to enter freely into the said chamber from the boiler, the
steam pipe as well as the condensing pipe communicating with and opening
into this chamber, in such a manner that the steam being admitted between the
pistons causes them to recede from each other towards the ends of the cylinder,
and the steam being then drawn off from, or condensed in the usual manner
between the pistons, they are driven towards each other by the pressure of the
atmosphere, which pressure on the said two pistons I employ in putting
machinery into action.
Secondly, I use a cylinder and piston as in the common atmosphere steam
engine; but, instead of fixing the cylinder, I cause it to move steam tight upon.
the pipe or pipes of communication with the boiler and injection cistern, or
with the boiler and condenser when a separate condensing vessel is employed;
and I fix such pipe or pipes to the framing or building, and I make the same
pipe or pipes sufficiently long to allow the cylinder free play thereon, so that in
case steam be admitted into the cylinder when the piston is at or near the
bottom of the cylinder, the same will cause the cylinder to descend, and the
piston to ascend; and the steam being then drawn off from or condensed
in the cylinder in the usual manner, the cylinder will be forced upwards by the
atmospheric pressure, the piston being at the same time forced downwards in the
usual manner; and the said action of the cylinder, in conjunction with that of
the piston, is employed by me in putting machinery into motion.
Thirdly, in steam engines worked by steam only I employ a cylinder closed
I cause
at both ends as usual; and, in addition to the piston in common use,
another piston to work in the same cylinder, and I make the rods of the said
pistons severally to work steam-tight through the opposite ends of the said
cylinder; the steam pipe and condensing pipe communicate with the middle
as well as with the ends of the cylinder. The steam enters into both ends of
the cylinder at one and the same time, and is drawn off from both ends at
another and the same time, immediately following the time last mentioned.
When the pistons meet near the middle of the cylinder, a space or chamber is
left between them, as in the first-described engine. When the communication
between the condenser and the two ends of the cylinder is opened a vacuum is

page_text: made between each end of the cylinder and the piston next or corresponding
to that end, and the steam being at the same time admitted between the two
pistons, the pistons are thereby made to recede from each other; and again at
the termination of the stroke, when the communication between the condenser
and the middle part or space of the cylinder is opened, and the steam shut off
from the boiler, a vacuum is made in that middle part or space; and the steam
being at the same time admitted at the two ends of the cylinder (and the
passage thence to the condenser being shut or closed), the two pistons are
thereby made to approach each other till they arrive at their first situation;
and I employ the said alternate recess and approach of both the said pistons
in giving motion to machinery. When a steam engine is to be worked by steam
of a greater power than the atmospheric pressure (commonly called a high-
pressure steam engine), I employ an engine of similar construction to this last
or thirdly described engine, except that I cause the communications, which are
in that engine stated to be made between the ends and middle part of the
cylinder, with the condenser, to be made in this case between the ends and
middle part of the cylinder and the open air.
Each piston in the first and third described engines, and the piston and
cylinder in the second described engine, may be respectively made to com-
municate with separate parts of the machinery to be put into motion by
cranks, beams, or other usual and well-known gear or apparatus; but I prefer
connecting the two pistons in the first and third described engines, or the
piston and cylinder in the second described engine, to one shaft by means of a
threefold crank, the middle crank being on the opposite side of the shaft to the two
extreme cranks thereof, the rod of the piston nearest the shaft being connected
with the middle crank and the piston farthest from the shaft in the first and third
engines, or the cylinder in the second described engine, being connected with the
two extreme cranks of the shaft by any usual and well-known method, so that
the two pistons in the first and third engines, or the piston and cylinder in the
second engine, may act upon the shaft in opposite directions, and cause the shaft
to revolve without occasioning any pressure or friction upon or against the
couplings in which it works, beyond that which arises from the weight of the
shaft and its appendages. In some cases I fix two common cylinders (having
their respective pistons and fittings) end to end, or invert one cylinder under
the other, either with or without a partition or flooring between them, and
admit the steam into both the cylinders at once, and make the vacuum in both
cylinders at once, so that the reaction upon one of the said cylinders shall,
either wholly or in part, be counterpoised or compensated by the reaction upon
the other cylinder; and in the above, as well as in all other cases wherein the
same may be required or prefered, I make the said cylinders of different

page_text: diameters, and, if need be, length of stroke; and farther, in the other con-
structions of my said improvements herein described, I do, if required or
prefered, make the opposite pistons and their correspondent cylinders, or the
parts of the cylinder in which the motions may or shall be performed or
made, of different diameters, and, if need be, length of stroke as aforesaid.
I construct steam engines, with the improvements herein-before and herein-
after described, in like manner, in other respects, as the steam engines already in
use; that is to say, I employ condensers, except in high-pressure engines and
boilers, and make the communications to introduce the steam into the cylinder
and produce the vacuum therein; and I open and close the said communica-
tions by regulators, valves, or cocks in the usual manner; and I surround the
cylinder, and parts which are to be kept hot, with a case containing steam or
hot air, or with wood or other bad conductor of heat, in the usual manner;
and I render the pistons and piston rods steam-tight by packing and stuffing
boxes in the usual manner; and I cause the motions of the pistons or of the
cylinder, when moved, to be performed in straight or right lined directions, by
means of guides, parallel gear, or other well-known apparatus used for such.
purposes; and I connect the pistons in the first and third engines, and the piston
and cylinder in the second described engine, to the shaft or shafts, or beams,
which give motion to the machinery by means of rods, shafts, and couplings,
also in the usual manner, or in such manner as shall appear most eligible to
the engineer or workman employed to construct the said engines.
And I do further declare that my said improvements, as to the structure and
fabrication thereof, subject, nevertheless, to be varied according to the circum-
stances of local situation, power required, and the general effects to be
produced, and in the relative dimensions of the parts thereof, which are easily
determinable by any competent engineer, from the said circumstances, are
described and illustrated in and by the Drawings hereunto annexed, and the
descriptive references which follow.
Figure 1, the first described engine. A, A, the cylinder, opened at both ends,
in which work the pistons C, B, leaving a space between them in the middle of
the cylinder, into which the steam and condensing pipes are introduced, as
at D and E; F, F, F, F, the piston rods, sliding in the bars or grooves G, G, G;
H, cross bar, to which the rod or rods of the piston C are fixed; J, working
rod of the piston B, working in the centres a, a, and attached to the centre
crank L; K, K, rods working on the ends of the bar H, at b, b, and attached
to the two extreme cranks N, N; N, L, N, the threefold crank shaft resting on
and working in the couplings M, M.
Figure 2, No. 1 and 2, the second described engine. A, A, the cylinder;
B, the piston; D, the steam and condensing pipe in one, fixed to the framing,

page_text: and branching off to the boiler and condenser, as at D and E, or made with a
partition, as at P. Figure 2, No. 2.-H, H, cross bar, fixed to the bottom
of the cylinder, and sliding in the grooved uprights G, G; c, c, pins or bolts
fixed to the upper end of the cylinder, and sliding in the same grooves G, G;
I, piston rod, attached to a crank shaft, as in Figure 1; K, K, rods attached
to the cross bar H, H, at B, B, and also to the cranked shaft, as in Figure 1 ;
O, stuffing box, fixed to the bottom of the cylinder, through which the fixed
pipe D works steam-tight. Figure 2, No. 2, the same as No. 1, but shewing
the position of the cylinder and piston when the piston and the bottom of the
cylinder are at their extreme distance from each other.
Figure 3, the third described engine. A, A, the cylinder closed at both ends,
and having stuffing boxes O, O, at each end, through which the rods F, F, of
the two pistons work; B, C, the two pistons at their extreme distance from
cach other; H, cross bar attached to the rod of the piston C, sliding in the
grooves G, G, and having the rods K, K, working on its extremities b, b,
the other ends of which rods work two extreme cranks of the shaft N, N;
I, working rod of the piston B, attached to the middle crank L; g, eye-bolt,
through which the extremity of rod F works; D, E, steam and condensing
pipes, communicating with the middle of the cylinder; R, R, steam
and condensing pipes communicating with the ends of the cylinder. The
wheel or wheels communicating the motion to the machinery, as also a fly-
wheel, when required, may be placed on the shaft between the couplings
M, M, as at S, S, Figure 1, or the shaft may be continued for that purpose
at one or both ends, as at T, Figure 3.
Figure 4. A, No. 1, A, No. 2, the two cylinders; B, C, the two pistons ;
D, D, pipes of communication with the boiler and condenser or injection
cistern; X, flooring or partition.
Figure 5. A, No. 1, A, No. 2, the two cylinders; B, C, the two pistons;
D, D, R, R, pipes of communication with the boiler and condenser; 0, 0,
stuffing boxes.
In both these Figures, 4 and 5, the end of the cylinder A, No. 2, may be
either fixed to a flooring or partition immediately under or against the end
of the cylinder A, No. 1, as at X, in Figure 4, or the ends of the two
cylinders may be fixed together without the intervention of a flooring or parti-
tion, as in Figure 5.
In witness whereof, I, the said Charles Broderip, have hereunto set my
hand and seal, the Thirtieth day of December, in the fifty-second year
of the reign of His said Majesty King George the Third.
C. BRODERIP. (L.S.)

page_text: AND BE IT REMEMBERED, that on the Thirtieth day of December, in
the year of our Lord 1811, the aforesaid Charles Broderip came before our
said Lord the King in His 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 stampt according to
the tenor of the Statute made for that purpose.
Inrolled the Thirtieth day of December, in the year of our Lord One
thousand eight hundred and eleven.