CERTAIN IMPROVEMENTS IN THE CONSTRUCTION OF STEAM ENGINES
Year: 1842

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I. JOHN
WOODCOCK, of Manchester, in the County of Lancaster, Millwright, send
greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Seventh day of June, One thousand eight hundred and forty-two,
in the fifth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said John Woodcock, Her especial license, full
power, sole privilege and authority, that I, the said John Woodrock, my
executors, administrators, and assigns, and such others as I, the said John
Woodcock, my executors, administrators, and assigns, should at any time
agree with, and no other, 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 and Wales and the Town of Berwick-upon-Tweed,
my Invention of "CERTAIN IMPROVEMENTS IN THE CONSTRUCTION OF STEAM
ENGINES;" in which said Letters Patent is contained a proviso that I, the
said John Woodcock, shall cause a particular description of the nature of my
said Invention, and in what manner the same is to be performed, to be
enrolled in Her Majesty's High Court of Chancery within six calendar months
next and immediately after the date of the said in part recited Letters Patent,
as in and by the same, reference being thereunto had, will more fully and a
large appear.
NOW KNOW YE, that in compliance with the, said proviso, I, the said
John Woodcock, do hereby declare that the nature of the said Invention, and

page_text: the manner in which the same is to be performed, is particularly described and
ascertained in and by the Drawings hereto annexed and the following ex-
planation thereof (that is to say):-
My Improvements in the Construction of Steam Engines apply, firstly, to
that class now called rotary engines, and is intended to be employed either as
a locomotive or stationary engine, being equally applicable to both.
Secondly, my improvements apply particularly to the slide or steam valve
and chamber, whether used in condensing or high-pressure engines, and either
employed for stationary, marine, or locomotive purposes.
And, thirdly, my improvements apply particularly to the stop valve used for the
purpose of shutting off the steam between the boiler and the engine.
Such being the nature of my said Invention, I now proceed to describe the
manner in which the same is to be performed. But, in order that my improve-
ments may be fully explained in constructive detail, I have attached to these
presents a Sheet of Drawings, representing their application to steam engines,
and marked the same with figures and letters of reference corresponding
with the following explanation thereof, similar letters being placed upon the
same parts of the machinery in all the Figures.
Firstly, my improvements in rotary engines are exhibited in the Drawings
at Fig. 1, which is a partial sectional elevation of the same, one of the side
plates being removed in order to shew the internal construction; Fig. 2 is an
end view of the same; and Fig. 3 is a transverse or cross section taken through
about the middle of the engine. a, a, is an outer cylinder or casing which
incloses the inner cylinder b, b, placed excentrically within it and mounted upon
a shaft c, which passes through stuffing boxes d, d, attached to the side plates
e, e, which enclose the outer cylinder a; this inner cylinder is divided by four
sliding pistons ff, coupled together in pairs by means of the links g, g; steam-
ways or passages h, h, are provided in the outer cylinder, having diagonal
apertures or openings i, i, (as seen in Fig. 3) for the passage of the steam to
and from the cylinder a; on steam being admitted from the valve box k, by
means of the pipe l, it will immediately exert its pressure against the piston f¹,
thus driving the inner cylinder round and escaping through the exhaust
pipe m. It will be observed that the pistons f¹ and f² are connected by means
of the link g', and that the pistons f³ and f* are connected by means of the
link g, and thus they will be slidden in and out as required by the revolution
of the cylinder b, the inner cylinder being made to work close up to the inner
surface of the outer cylinder, and packed with a rib of brass or other metal
to prevent the escape of steam. A small groove o, o, is turned about of an
inch deep in the outer cylinder, extending from the steamways to the packing

page_text: at top. as shewn by dotted lines in Fig. 1, for the purpose of allowing a small
portion of the steam to escape at the packed end of the piston. It will be
seen in Fig. 3 that rings of brass or other metal are placed in grooves turned
in the outer plates to act as a packing between the outer plates and the sides of
the cylinder, and keeping the whole perfectly steam-tight; the outer ends of
the pistons f. f. are also to be similarly furnished with metallic packing. An
ordinary slide valve q is provided whenever it is required to reverse the
action of the engine, and in large engines six or eight pistons may be em-
ployed. Although it may appear that rotary engines of a somewhat similar
construction have been before known and in use, I desire it to be distinctly
understood, that my improvements have not hitherto been applied, particularly
as regards the links g¹ and g² for connecting the pistons. These I construct
with open mortices, so that they shall act exactly the same as if they were
passed through the shaft of the inner cylinder, which would be a great objec-
tion, as it would materially weaken such shaft and they could not be so readily
removed and repaired; and also the steamways or ports into the cylinder
being made in diagonal or spiral openings, is of considerable importance, as
the pistons will pass the openings without being so subject to wear. And these
improvements in rotary engines I particularly claim as my Invention.
Secondly, my improvements in the steam chamber and slide valves of
steam engines are represented at the sectional Figs. 4 and 5, which
exbibit the slide valve and its seating, with the steam ports or ways opening
into the cylinder. The steam cylinder a, a, has four apertures or passages
for the steam b, b, and c, c; two for the induction and two for the
eduction. Those for the induction are to be in proportion to the diameter
of the cylinder according to ordinary calculations, and those for the eduction
c, c, to be as one and a half is to one of the induction in area (or any other
proportion if preferred). The slide valve d is so constructed as to open and
shut all the four apertures, and is also provided with a fifth aperture e, for the
exhaust steam, which escapes at the pipe f, between the cylinder and face
plate. The slide valve d, d, is to be worked from the crank shaft as in
common, opening and closing the apertures 6 and e alternately. The steam
cylinder may have six or more apertures, and supposing it is required to have
the apertures for the eduction of the steam double the width of the induction,
the eduction may be divided into two apertures, top and bottom, placing the
apertures for the induction in the centre, and introducing all the spent steam
from the eduction apertures into the hollow part of the slide valve, it will
escape by another aperture into a pipe conducting it to the condenser, or open
air, in the same manner as when only four apertures are used. There are

page_text: also small spaces, g, g, between the slide valve and cylinder facing, for the
passage of steam, in order to reduce the friction by thus relieving the valve
from the outer pressure of the steam. This arrangement of the slide valve I
consider particularly adapted for stationary engines, where the load is con-
tinually fluctuating by the machinery being often thrown in and out of gear,
and also for marine engines where the full force of the steam is frequently
required. And this improvement in the construction and arrangement of the
slide valves I distinctly claim as my Invention.
Thirdly, my improvements in the stop valve to be employed between the
boiler and engine, are shewn in Fig. 6, which is a face view of the valve, Fig. 7
a cross section, and Fig. 8, which is an external view of the same. This valve
may be employed for the purpose of closing the communication for the passage
of steam between the boiler and the engine, or in the various processes of
dyeing, bleaching, or printing, and in all situations where a great quantity of
steam or water is required, and by applying a spout may also be converted into
a stopcock. a is a short pipe with flange for the entrance, and 6 a similar
pipe and flange for the exit, a slide or door c for stopping the passage has a
groove d, d, formed in the upper part, in which an eccentric e is caused to
work, thus opening and closing the slide as required, by means of partially
turning the handle f, fixed upon the outer end of the shaft g of the eccentric;
a stuffing box h, h, is provided for the purpose of making the whole steam-
tight. And this novel construction of stop valve I also claim as my Invention.
In witness whereof, I, the said John Woodcock, have hereunto set my
hand and seal, this Third day of December, in the year of our Lord
One thousand eight hundred and forty-two.