CERTAIN IMPROVEMENTS IN STEAM ENGINES
Year: 1855

page_text: LETTERS PATENT to James Porritt, of Stubbins Vale Mills, near Rams-
bottom, in the County of Lancaster, Manufacturer, for the Invention
of
CERTAIN IMPROVEMENTS IN STEAM ENGINES.
Sealed the 4th September 1855, and dated the 29th March 1855.
PROVISIONAL SPECIFICATION left by the said James Porritt at the Office
of the Commissioners of Patents, with his Petition, 'on the 29th March
1855.
I, JAMES PORRITT, of Stubbins Vale Mills, near Ramsbottom, in the County
of Lancaster, Manufacturer, do hereby declare the nature of the Invention for
"CERTAIN IMPROVEMENTS IN STEAM ENGINES" to be as follows:-
My Invention consists in a mechanical arrangement connected with the
governor of the steam engine, by which the extending or diminishing the lift
of the Cornish or equilibrium valve by the tappet is accomplished in a more
certain and instantaneous manner than heretofore, and the speed of the engine
regulated and controlled irrespective of the amount of work to be performed
within the extent of the power of the engine.
And one arrangement of the manner in which my Invention is to be per-
formed and carried into effect is described in reference to the annexed sketch,
in which A represents the revolving tappet which periodically lifts the rod B
connected with the steam engine valves; but instead of allowing this tappet

page_text: to touch the foot of the rod B, I interpose the horizontal rod C; this rod C is
connected with the governor. rod D by a series of levers marked d, so that as the
governor rod D rises or falls, it forces the rod C forward, as indicated by the
arrow, or retires it in the opposite direction. Thus the position of the rod C
will extend or diminish the lift of the rods B, and the valves with which they
are connected; for, supposing the rod C to be forced in the direction of the
arrow as far as the point e, the tappet A will impinge a certain part of its
revolution, and hold up the rod B; but on the other hand, supposing the
rod C retired, the tappet A will revolve without interfering with the rod B,
and the engine would immediately stop, and in this way the position of the
rod C governs the lift of the engine valves.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Porritt in the Great Seal Patent Office on the 28th
September 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
PORRITT, of Stubbins Vale Mills, near Ramsbottom, in the County of Lan-
caster, Manufacturer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-ninth day of March, in the year of our Lord
One thousand eight hundred and fifty-five, in the eighteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,

page_text: the said James Porritt, Her special license that I; the said James Porritt, my
executors, administrators, and assigns, or such others, as I, the said James
Porritt, my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and, at all times thereafter. during ithe
term therein expressed,. should: and- lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the Channel
Islands; and, Isle of Man, an Invention for "CERTAIN IMPROVEMENTS IN STEAM
ENGINES," upon the condition (amongst others) that I, the said James Porritt,
by an instrument in writing under my hand and seal, should. particularly
describe and ascertain the nature of the said. Invention, and in what manner
the same was to be performed; and cause the same to be 'filed in the Great
Seal: Patent Office within six calendar months next and immediately after
the date of the said Letters Patent:
**
NOW KNOW YE, that I; the said James Porritt, do hereby declare the
nature of my said. Invention, and in what manner the same is to "befper-
formed, to be particularly described and ascertained.in' and by the following
statement; that is to say:
The nature of my Invention consists in an improved combination of parts
acted upon by the governor of a steam engine, whereby the lift or amount of
opening of the valve, and consequently the quantity of steam admitted to the
cylinder, is fegulated, in proportion to the power required to be exerted by
the steam engine.
p
And in order that my Invention may be fully understood and readily. carried
into effect, I will proceed to describe the means" pursued by me, reference
being. had to the accompanying Drawing, and to the figures and letters marked
thereon.
Figl represents a front elevation, Fig 2 a' plan, and: Figs. 3 and 4, side
elevations, of my improvements, and of part of a steam engine to which my
improvements are applied.
A represents a connecting rod which is in communication:.with a ball
governor. of the usual construction, and rises or:falls according to the .expán-
sion or collapsing of the governor balls; the lower end of the rod. A is jointed
to the lever X, which is in connexion with the lever B by means of the link Y.
The lever B vibrates: 'on thé fulcrumi stud b, and it communicates motion to
the lever. D. by means of the link C; this lever Dis fixed on the shaft E
Another lever F is also fast on the shaft E, the extremity of which is connected
to the wedge rod: G. The ordinary, tappet His placed on the revolving shaft. I;
and the perpendicularirod K; for opening the. engine valves, is immediately
above sit, but sufficiently distant to allow the tappet.Heto revolve without

page_text: touching it; conséquently the rod K cannot be raised without the intervention
of the wedge rod G. M is a counterweight for drawing back the wedge rod
G, when required.
The Drawing represents the parts for working the lower valve, and a similar
arrangement works the upper valve, as shewn in Fig. 1.
In Fig. 2, N represents part of the cylinder, and O, O, are the side pipes;
these and all the other parts of the engine not shewn or referred to, are made
in the usual manner.
When the rod A is forced down or depressed by the action of the governor,
owing to the increased speed of the engine, the motion is conveyed through the
levers B, D, F, and the wedge rod G is partially withdrawn, as seen in the
tinted parts at Fig. 4, thus presenting the thinner substance of the wedge
between the tappet H and rod K, thereby decreasing the lift of the valve and
diminishing the quantity of steam admitted to the cylinder, and reducing the
speed of the engine. When the speed of the engine decreases, the action of
the governor elevates the rod A, and the wedge rod G is immediately forced
forward, or into the position indicated by dotted lines in Fig. 4; consequently
the thicker substance of the wedge being inserted between the tappet H and rod
K, increases the lift of the valve, and allows more steam to enter the cylinder,
thereby increasing the speed of the engine. When the wedge rod G is
drawn back to the full extent, there will be no lift of the valve, and the engine
will stop. By this means no throttle valve is required, and any amount of
work within the power of the engine may be put on or taken off without
varying its speed for more than a few strokes. By disconnecting the governor
from the rod A at any convenient place, the wedge rod G is withdrawn by the
action of the counterweight M, and the engine is stopped; thus the power of
stopping the engine may be placed under the control of the manager of each
room in the works. Engines constructed with slide valves may be worked as
before described by the removal of the throttle valve, and the substitution of an
equilibrium or other suitable valve.
I am aware that the parts for conveying the action of the governor to the
Invention
wedge rods G may be varied; but the essential characteristic of my
consists in adjusting the opening and closing of valves by admitting and cutting
off the steam, as may be required, thereby dispensing with the throttle or check
valve, by which arrangement the steam is allowed to enter the cylinder in full
force, according to the pressure in the boiler.
Having thus stated the nature of my Invention, and described the manner
of performing the same, I wish it to be understood that I do not limit myself
to the details herein set forth, as the same may be varied according to the

page_text: peculiar construction of the engine to which my improvements are applied;
but what I do claim is, the wedge rod marked G, when used for the purpose
described.
In witness whereof, I, the said James Porritt, have hereunto set my
hand and seal, this Twenty-seventh day of September, in the year of
our Lord One thousand eight hundred and fifty-five.
Taken and declared at Manchester, in the
County of Lancaster, this Twenty-seventh
day of September, One thousand eight
hundred and fifty-five, before me,
JAMES BARROW,
JAMES PORRITT. (L.B.)
A Commissioner to administer Oaths
in Chancery in England.