IMPROVEMENTS IN STEAM ENGINES
Year: 1867

page_text: LETTERS PATENT to James Petrie, of Rochdale, in the County of
Lancaster, Engineer, for the Invention of "IMPROVEMENTS IN STEAM
ENGINES."
PROVISIONAL SPECIFICATION left by the said James Petrie at the
Office of the Commissioners of Patents, with his Petition, on the
9th January 1867.
I, JAMES PETRIE, of Rochdale, in the County of Lancaster, Engineer, do
bereby declare the nature of the said Invention for "IMPROVEMENTS IN STEAM
ENGINES," to be as follows:-
My Invention refers, firstly, to horizontal engines, and consists in an
arrangement for effecting the cut-off motion by valves formed as pistons, and
which have an axial as well as a sliding motion. The differential apparatus
of the construction ordinarily used I place between a pair of cylinders; this
apparatus gives motion to a shaft on which there are two cams acting on each
side upon rocking levers furnished with rods which are caused by the said
cams to move in opposite directions, and by these means the valve rods
are, through the intervention of rocking levers, turned upon their centres
as usual.
Another part of my Invention relates to pistons of steam engines, and
consists in forming them with a solid non-expanding part fitting the cylinder
in combination with an expanding part or parts. As an illustration of this

page_text: part of my Invention I form a solid piston upon the piston rod, and on each
side I place expanding rings of any usual construction; but one ring only
may be used if desired. This part of my Invention is also applicable to piston
valves.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Petrie in the Great Seal Patent Office on the 9th
July 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
PETRIE, of Rochdale, in the County of Lancaster, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Ninth day of January, in the year of our Lord
One thousand eight hundred and sixty-seven, in the thirtieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
James Petrie, Her special license that I, the said James Petrie, my exe-
cutors, administrators, and assigns, or such others as I, the said James Petrie,
my executors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during the
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 "IMPROVEMENTS IN STEAM ENGINES,"
upon the condition (amongst others) that I, the said James Petrie, 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 Petrie, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement and accompanying Drawings, that is to say:―
My Invention refers, firstly, to horizontal engines, and consists in an
arrangement for effecting the cut-off motion by valves formed as pistons, and
which have an axial as well as a sliding motion.
Secondly, my Invention relates to pistons and piston valves of steam
engines, and consists in forming them with a solid non-expanding part fitting
the cylinder in combination with expanding parts.

page_text: The first part of my Invention is shewn in side view at Fig. 1, cross section
at Fig. 2, and plan view at Fig. 3.
ს
The box of the usual differential apparatus is shewn at a, communicating
motion to a shaft 6 upon which is a cam c; this cam is situate between two
plates d rocking upon a centre e carried by the foundation plate, and it acts
against rollers f mounted upon the said plates. To the upper end of the
plates d is jointed a rod g, the other end of which is connected to a boss h
situate between two standards i and jointed to a lever k which at its lower end
is attached to the valve rod passing into the valve box m; on each side of
the standard i is a lever n mounted upon a shaft o, one end of which is prc-
vided with a lever p to which the ordinary excentric rod q is connected. The
levers n carry links r which are jointed at their other ends to the valve rod 7,
upon which are mounted upright arms s carrying a rod t which passes through
slots u formed in the standards i and through the boss h above mentioned.
The operation is as follows:-The usual action of the excentric upon the
rod 7, by causing the shaft o and levers p to vibrate will through the links 7,
cause the valve rod 7 to slide to and fro, the rods s attached to the said valve
rod being free to move transversely in the boss ; simultaneously with this
the differential apparatus acting by means of the cam cupon the plates & will
cause them to rock forward or backward, and thus through the connecting
rod g impart a vibratory motion to the valve rod 1, whereby the valve will be
caused to rotate and effect the necessary regulation in the flow of steam.
I have in the foregoing, for the sake of simplicity, alluded to one set of
apparatus for one valve box only, but I apply the differential apparatus
between two steam cylinders, and upon the shaft 6 place a second cam c*,
acting in a similar manner to that above described, upon rollers placed
between two vibrating plates d*, the rod g* of which proceeds to apparatus
which is a mere repitition of that above described, and which is not therefore
shewn in the Drawings.
My second improvement is shewn at Figs. 4, 5, 6, in the first of which a
represents a solid block of metal attached to the piston rod band turned so
as to fit the cylinder; this part is coved out in any desired manner for the
purpose of lightening it; around this solid part are placed expanding rings c
forced outward by springs in the ordinary manner and confined in their places
5 by covers d. Figs. 5 and 6 represents this part of my Invention applied to a
piston valve; the solid part is shewn at e, and the expanding rings at f forced
outwards by springs g and confined by covers h. In this instance the valve is
supposed to be arranged for a sliding motion and an axial motion, for which
purpose it is provided with openings i formed around the circumference, and

page_text: which are brought by the sliding motion opposite to other openings & leading
to the cylinder; but if the valve be turned on its centre then these openings:
are more or less contracted, as is well understood.
Having thus described and ascertained the nature of my said Invention,
and the manner in which the same is to be performed, I desire it to be under-..
stood that I claim as secured to me under the above in part recited Letters
Patent,
Firstly, and as applied to horizontal engines, the arrangement, substantially
as described, for actuating valves which have an axial as well as a sliding
motion.
Secondly, forming pistons and piston valves with a solid part fitting the
cylinder in combination with expanding parts.
In witness whereof, I, the said James Petrie, have hereunto set my
hand and seal, this Eighth day of July, in the year of our Lord One
thousand eight hundred and sixty-seven.
JAMES PETRIE. (L.S.)