IMPROVEMENTS IN STEAM ENGINES
Year: 1853

page_text: LETTERS PATENT to Thomas Edwards, of the Islington Foundry,
Birmingham, in the County of Warwick, Engineer, for the In-
vention of "IMPROVEMENTS IN STEAM ENGINES."
aled the 14th June 1858, and dated the 18th April 1858.
PROVISIONAL SPECIFICATION left by the said Thomas Edwards
at the Office of the Commissioners of Patents, with his Petition,
on the 13th April 1858.
I, THOMAS EDWARDS, of the Islington Foundry, Birmingham, in the
County of Warwick, Engineer, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN STEAM ENGINES" to be as fol-
lows:-
This Invention relates to a pecular arrangement of the valves and
cranks of high pressure and low pressure steam engines when working
conjointly, and consists in adapting the lead on the exhaust side of the
valve of the high pressure engine, to suit the advanced position of the
crank of the condensing engine, so that the exhaust from the high
pressure cylinder takes place at the moment that the crank of the con-
densing engine passes the dead centre.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Edwards, in the Great Seal Patent
Office, on the 18th October 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
THOMAS EDWARDS, of the Islington Iron Foundry, Birmingham, in the
County of Warwick, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirteenth day of April, in the year
of our Lord One thousand eight hundred and fifty-three, in the six-
teenth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Thomas Edwards, Her special licence
that I, the said Thomas Edwards, my executors, administrators, and
assigns, or such others as I, the said Thomas Edwards, my exccutors,
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
Thomas Edwards, by an instrument in writing under my hand and seal,
should particularly describe and ascertain the nature of the said In-
vention, 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 Thomas Edwards, 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, reference being had to the accom-
panying drawings, and to the letters and figures marked thereon, that is
to say:
⋅
My said Invention relates to a simple arrangement or modification of
duplex cylinder expansion, or Woof's engine, wherein the "lead" on
the exhaust side of the valve of the high pressure cylinder is so
adapted or set, in reference to the low pressure cylinder arrangements,

page_text: that the high pressure exhaust shall take place at or about the instant
that the crank of the low pressure cylinder passes the dead centre.
This arrangement produces great economy in fuel, as the steam is made
to act more effectively than in engines as ordinarily fitted up. And
in order that my said Invention may be properly understood, I shall
now proceed to describe the several figures on the sheets of drawings
hereunto attached.
Figure 1, on Sheet 1, of my drawings represents a longitudinal ele-
vation, partially in section, of a duplex cylinder beam steam engine
built and arranged according to my improvements; the larger or low
pressure steam cylinder, valve chest, condenser, air pump, and hot well
being represented in vertical section, whilst the remainder of the work-
ing parts are in external elevation. Figure 2, on the same sheet, is a
vertical longitudinal section of the smaller or high pressure steam
cylinder and valve chest detached, indicating the relative positions of
the high pressure steam piston and valve, as corresponding with the
delineated positions of the similar details of the low pressure steam
cylinder shewn in Figure 1. Figure 1, on Sheet 2, of my drawings, is
a plan of the combined engine with the two beams and upper working
details removed, the high pressure steam cylinder being represented in
horizontal section. The engine is of the portable beam class, carried
on the bed of masonry A, by means of the pair of cast iron sole
plates B, bolted down by long holding-down bolts passed vertically
through the sole.plates and through the masonry. On these sole plates
are bolted down the pair of pillars C, supported by the rectangular
standards D, as the main carrying framing of the two overhead
beams E, F. These beams, which work on main stud centres, set in
pedestal bearings, bolted on the top of this framing in the usual
manner, have each a connecting rod G, H, jointed to their ends, and
passing downwards to their respective cranks I, J, on the two extreme
ends of the main first motion shaft K. The two cranks I, J, that is,
the high and low pressure cranks, are so set with regard to each other,
that as, in Figure 1, on Sheet 1, of my drawings, when the low
pressure crank J, is on its bottom centre or dead point, the high
pressure crank I, has nearly arrived at its upper centre. The main

page_text: shaft K, carries a fly-wheel L, at its centre, and actuates a gover-
nor M, between the two beams in the usual manner: at the opposite
ends of the sole plates are the high and low pressure steam cylinders
N, O, bolted down to their respective foundation plates by square
flanges, their pistons P, Q, being respectively connected through their
rods R, S, with the parallel motion ends of the main beams E, F.
The steam valves T, U, for the two steam cylinders are of the long
D kind, with their working spindles V, W, passed upwards through
stuffing boxes on the tops of the valve chests, for connection by means
of side rods with the rods of the main shaft eccentrics X, Y. The
high pressure steam is conveyed direct from the boiler through the
pipe Z, to the lower end of the valve chest of the valve T, of the
smaller high pressure cylinder N; and the exhaust of the used steam
from this cylinder takos place through the botton branch a, beneath
the cylinder. From this branch the waste or primarily used steam
passes along the pipe b, entering the valve chest of the valve U, of the
larger low pressure cylinder through the branch c. The used steam
from the low pressure cylinder finally exhausts through the branch d,
into the vertical descending pipe e, to the condenser f, set in the foun-
dation recess. The injection water for condensation is led in by the
horizontal pipe g, where it mingles with the waste steam at the per-
forated hemispherical diaphragm h, through which access is obtained to
the body of the condenser. The results of condensation pass through
the foot passage i, to the bottom of the air pump j; the bucket h, of
which is actuated by the 1, jointed to the beam overhead. The air
pump discharge is through the lateral port m, into the hot well n,
whence the water and vapour escape through the pipes o, p; whilst the
feed pump q, also worked from the overhead beam, takes away the
boiler feed water from the hot well by the bottom pipe 7. For blowing
through, to clear the passages of air on starting the engine, the high
pressure boiler steam pipe Z, has a small branch pipe s, passing
into the intermediate exhaust pipe b, at t. The engine is worked in
every respect the same as a common duplex cylinder expansion engine.
As delineated in the several parts of my drawings, the ligh pressure
piston P, has nearly completed its down stroke, and as it is working

page_text: "
with considerable "lead on the valve, the steam which has been used
in the downward stroke has just commenced to escape through the
upper port u, and through the hollow of the valve T, into the inter-
mediate pipe b, for conveyance to the upper side of the low pressure
piston Q, now at the very top of its stroke. Similarly, when the low
pressure piston Q, arrives at the termination of its downward stroke,
when its crank pin will be on its upper dead centre, the high pressure
crank I, will be as far in advance towards its bottom dead centre as I
have herein represented it in reference to its upper centre. Hence the
full exhaust of the used steam from the small high pressure cylinder
takes place, so as to admit of the expansion of such steam into the
larger area of the low pressure cylinder to take place just at the instant
the larger low pressure piston is at or has just moved or is moving from
its dead centre. By this means the best possible effect is obtained
from this system of expansion, and a more uniform and effective
power is obtained than has hitherto been the case in expansion steam
engines.
Having now described and particularly ascertained the nature of my
said Invention, and the manner in which the same is or may be used
or carried into effect, I would observe, in conclusion, that I do not con-
fine or restrict myself to the precise details or arrangements which 1
have had occasion to describe or refer to, as many variations may be
made therefrom without deviating from the principles or main features
of my Invention; but what I consider to be novel and original, and
therefore claim as the Invention secured to me by the herein-before in
part recited Letters Patent, is,-
First, the general arrangement and construction of steam engines as
herein-before described.
Second, the system or mode of arranging and constructing duplex
cylinder expansive steam engines in such manner that the exhaust
steam from the high pressure cylinder shall enter the low pressure
cylinder at or about the instant of the passage of the crank of the low
pressure cylinder over its dead centre.
Third, the system or mode of arranging combined duplex cylinder
expansive steam engines in such manner that their respective cranks

page_text: shall be disposed at any angle or position with regard to each other
between a right angle and a diametrically opposite position, the lead
being given to the low pressure or expansive cylinder.
Fourth, the system or mode of arranging a high pressure steam
engine to work in combination with a low pressure expansive engine in
such manner that the respective cranks shall be disposed at any angle
with regard to each other, between a diametrically opposite position
and a right angle, lead' being given to the expansive cylinder.
In witness whereof, I, the said Thomas Edwards, have hereunto
set my hand and seal, the Twelfth day of October One thou-
sand eight hundred and fifty-three.
THOMAS EDWARDS. (L.S.)