CERTAIN IMPROVEMENTS IN STEAM ENGINES
Year: 1836

page_text: TO ALL TO WHOM THESE PRESENTS SHALL, I, JAMES DIGGLE,
of Bury, in the County Palatine of Lancaster, Engineer, send greeting.
WHEREAS His present most Excellent Majesty King William the Fourth,
by His Letters Patent under the Great Britain, bearing date at West-
minster, the Eighth day of March, in the sixth year of His reign, did, for
Himself, His heirs and successors, give and grant unto me, the said James
Diggle, His especial licence, full power, sole privilege and authority, that I,
the said James Diggle, 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, Wales, and the Town of Berwick-upon-
Tweed, my Invention of "CERTAIN IMPROVEMENTS IN STEAM ENGINES;" in which
said Letters Patent is contained a proviso that I, the said James Diggle,
shall cause a particular description of the nature of my said Invention, and in
what manner the same is to be performed, to be inrolled in His 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 at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
James Diggle, do hereby declare that the nature of the said Invention, and
the manner in which the same is to be performed, is particularly described and
ascertained in the Drawings hereto annexed, and the following explanation
thereof, that is to say:-

page_text: My improvements in steam engines consist in the first place in a peculiar
arrangement of the parts of low-pressure or condensing stationary steam
engines, by which arrangement the ordinary beam or main lever is dispensed
with, and the whole of the engine is erected in a much more convenient and
compact form, and this is effected by placing the air-pump below or under the
steam cylinder in a direct line therewith, whereby the piston of the steam
cylinder and the bucket of the air-pump can be worked at the same time by
means of one piston rod passing through both ends of the cylinder.
And secondly, in constructing the ordinary D or square slide valves for the
ingress and egress of the steam to the cylinders of engines, with metallic
packing rendered elastic by means of the application of wedge-formed pieces
and springs, as hereafter described.
In order to elucidate the particular features of novelty which I claim as my
Invention, I shall now refer to the Drawing accompanying these presents, in
which sufficient portions of my improved steam engine is shewn to render the
same intelligible, and also different views of the common D valve for steam
engines, in all of which figures the same letters of reference point out corre-
sponding parts. Figure 1 is a sectional side elevation of 'my improved steam
engine, and Figure 2 a front view of the same, also partially shewn in section.
A is the steam cylinder; B, the piston; C, the air pump; D, the condenser;
E, E, the slide valves. a, a, are the standards or side frames of the engine
supported upon suitable foundations of stone or other material; b, b, is the
crank shaft carrying its fly wheel, and turning in proper bearings or plummer
boxes on the standards, and through which shaft the power is communicated
from the steam cylinder to the machinery required to be driven by the engine;
at one end of this shaft the crank c is mounted, being immediately over the
central line of the steam cylinder. The crank is connected by its pin to the
rods d, d, d, which are jointed at their lower ends to a cross piece e firmly
secured to the piston rod f; and as this rod works.up and down-through-the-guide
piece or stuffing box g, fixed to the framing of the engine, the requisite parallel
motion is obtained, that is, the direct vertical ascent and descent of the piston
rod. It will be seen that the piston rod works through the stuffing box
formed in the cover of the cylinder as usual, and extends through the piston B,
and another stuffing box in the bottom of the cylinder, its lower end being
attached to the air-pump bucket i, working in the air-pump C. The slide
valves E, E, for the admission and the exit of the steam to the steam cylinder,
are worked by the rod m and eccentric n on the main shaft b.
The second feature of novelty which I claim as my Invention is more parti-
cularly shewn in Figures 3, 4, 5, 6, and 7, Figure 3. being a front or face
view of the slide valve detached from its steam chamber, the metallic packing

page_text: being removed; Figure 4, a back view of the same; Figure 5, a vertical
section taken through the valve and its metallic packing in the line a, b, to
shew the wedges and springs; Figure 6 is a horizontal section of the same in
the line c, d, and Figure 7 is a plan or horizontal view of the valve, as situate
in its steam chamber, which is shewn in section; p, p, are the metallic
segments or packings, and are severed into portions where the wedge-formed
pieces 7, 9, are placed. It will be perceived that the segments or packings are
rendered elastic by means of the wedges 7, 7, being forced by the springs r,r,
into the division of the segment of packing, the springs being placed behind
the wedges, and bearing against the D valve; the springs may be of the
form represented in the Drawing, or they may be heliacal, eliptical, or of any
other suitable from; the segments of metallic packing are kept in their present
position by the semicircular piece 8, s, which is screwed or bolted to the bosses
t, t, t, projecting from the bottom piece or plate u, u.
Having described the principal features of improvement which I consider to
be new, I wish it to be understood that I do not claim separately any of the
various parts of a steam engine which have been here described, but I claim as
my Invention: first, the above described combination and arrangement of the
various parts of low-pressure or condensing steam engines; and secondly, the
application of the above described elastic metalic packings to the steam valve
known by the name of the D valve or square valve for engines built upon the
high or low pressure principle either stationary or locomotive.
In witness whereof, I, the said James Diggle, have hereunto set my
hand and seal, this Sixth day of September, in the year of our Lord
One thousand eight hundred and thirty-six.