IMPROVEMENTS IN STEAM ENGINES
Year: 1875

page_text: :-
LETTERS PATENT to Henry Hughes, of Leicester, in the County of
Leicester, Mechanical Engineer, for the Invention of "IMPROVEMENTS
IN STEAM ENGINES."
Sealed the 25th June 1875, and dated the 1st February 1875.
· PROVISIONAL SPECIFICATION left by the said Henry Hughes at the
Office of the Commissioners of Patents, with his Petition, on the
1st February 1875.
I, HENRY HUGHES, of Leicester, in the County of Leicester, Mechanical
Engineer, do hereby declare the nature of my said Invention for "IM-
PROVEMENTS IN STEAM ENGINES," to be as follows:-
My Invention relates more particularly to double cylinder steam
engines of the class described in the Provisional Specifications filed by
me Novr. 3rd, 1874, No. 3787, and November 19th, 1874, No. 3976,
respectively, and consists of an improved arrangement of the valves and
of the gear or apparatus connected therewith, whereby the number of
joints and bolts required in a double cylinder engine is considerably:
diminished, the length of the ports is reduced to a minimum, and

page_text: great simplicity in the mechanism for regulating the speed of the engine
is obtained.
In carrying out my Invention I form or fix on one end or cover of
each of the cylinders a valve box or steam chest having three openings,
viz., one communicating with the steam pipe, one forming the steam
port, and the other leading to the exhaust. In this valve box or steam
chest I fit a slide valve, or a valve of any suitable construction, but by
preference an oscillating valve having its centre of oscillation at right
angles to the axial line of the cylinder. The faces of this valve are made
of a circular form in transverse section, the valve facing and the interior
of the valve box or steam chest being of a corresponding cylindrical
shape, and they are so arranged as to cover and open the `several
passages at the desired periods for the purpose of admitting and cutting
off the supply of steam as required. The centre of oscillation of the
valve may be placed in a line with the longitudinal axial line of the
cylinder if desired.
The valves so arranged may be actuated in any suitable manner,
but I prefer to operate them by means of a pin or stud, or a disc
plate attached to the crank shaft of the engine as next herein-after
described.
I form on or attach to the fly wheel (or a disc) carried on the engine
shaft a boss having a groove or recess extending diametrically across the
same, in which groove or recess there is fitted a weight which is capable
of sliding therein, but is limited or restrained in its motion by the action
of a helical or other spring attached at one end to the weight, and at.
the other end to a projection on the boss. The sliding weight carries the
pin or stud before mentioned for actuating the valves, and thus forms a
governor by means of which the throw of the valve is altered or regu-
lated according to the speed of the engine.
SPECIFICATION in pursuance of the conditions of the Letters Patent, 3
filed by the said Henry Hughes in the Great Seal Patent Office on
the 24th July 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
HUGHES, of Leicester, in the County of Leicester, Mechanical Engineer,
send greeting..
:
3

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of February, in the year
of our Lord One thousand eight hundred and seventy-five, in the
38th year of Her reign, did, for Herself, Her heirs and successors.
give and grant unto me, the said Henry Hughes, Her special license;
that I, the said Henry Hughes, my executors, administrators and
assigns, or such others as I, the said Henry Hughes, my executors,
administrators, or 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'
Henry Hughes, my executors or administrators; 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 imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Henry Hughes, 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 accompanying Drawings
and to the letters and figures marked thereon, that is to say :-
My said Invention relates more particularly to double cylinder steam
engines of the class described in the Specificaton of Letters Patent,
granted to me, dated November Third, One thousand eight hundred and
seventy-four, No. 3787, and November Nineteenth, One thousand eight'
hundred and seventy-four, No. 3976 respectively, and consists of an
improved arrangement of the valves and of the gear or apparatus
connected therewith whereby the number of joints and bolts required in
a double cylinder engine is considerably diminished, the length of the
ports is reduced to a minimum, and great simplicity in the mechanism
for regulating the speed of the engine is obtained.
·
And in order that my said Invention may be fully understood I shall
now proceed more particularly to describe the same, and for that purpose
shall refer to the several Figures on the annexed Sheet of Drawings, the
same letters of reference indicating corresponding parts in all the Figures.

page_text: Figure 1 of my Drawings represents a longitudinal section of a portion of
a cylinder, shewing the application thereto of a valve and ports arranged
in accordance with my Invention; Figure 2 represents a side elevation;
and Figure 3 is an under plan of a crank disc or eccentric for actuating
and regulating the throw of the. valves.
Figure 4 is a longitudinal section drawn to a reduced scale.
Figure 5 is a corresponding plan, and Figuro 6 is a transverse section
of an engine having the improvements illustrated in Figures 1, 2, and 3,
applied thereto..
A, A, are the cylinders; a, a, are their covers, on cach of which I
form a valve box or steam chest B having three openings b, c, d, the
opening 6 of which communicates with the steam pipe C, the opening c
forms the steam port whilst the other, d, leads to the exhaust.
The steam pipe C may either be fitted at that end of the cylinder
which is in close proximity to the cover a, as shewn in Figure 1 or at
the opposite end of the cylinder at the point C₁ (Figures 4 and 5). In
the latter case the steam is admitted to an annular chamber e formed
between the internal surface of the cylinder and the external surface of
a tube f(composed, by preference, of steel) which acts as the cylinder
proper, the steam thus surrounding the cylinders f on its way to the
opening in the valve box B, and constituting a steam jacket for main-
taining the cylinders at a sufficiently high temperature. An exhaust
pipe D leading from the exhaust port d may also be fitted to the cylinder
at the side opposite to that at which the steam pipe C is fitted, as shewn
in Figure 1, or the exhaust steam may be allowed to escape direct from
an outlet D' formed in the cylinder cover a, as shewn in Figure 4. In all
cases however the passages are arranged in such a manner as to admit of
the covers a, a, containing the valves, being removed whilst leaving
such pipes and connections as may be employed intact.
In the valve box B I fit a slide valve, or a valve of any suitable con-
struction, but by preference an oscillating valve, having its centre of
oscillation at right angles to the axial line of the cylinder.
In my Drawings the description of valve lastly mentioned is shown as
adopted; g, g, are the valves, the faces of which are made of a circular
form in transverse section, the valve facing and the interior of the valve
box being of a corresponding cylindrical shape, and which are so arranged
as to cover and open the ports c, d, at the desired periods for the purpose of

page_text: admitting and cutting off the supply of steam and exhausting, as required.
The centre of oscillation of the valve may be placed in a line with
the longitudinal axial line of the cylinder if desired. The valves are so
arranged that the steam is in the course of being admitted to one
cylinder whilst the opposite cylinder is exhausting, the pistons E, E,
being acted upon alternately, but upon one side only, as described in the
first mentioned of my said former Specifications.
-
The valves may be actuated in any suitable manner, but I prefer to
operate them by means of the arrangement of crank disc or eccentric,
shewn in detail in Figures 2 and 3, and which constitutes another
feature of my Invention. F is the disc which may either be provided
with a boss for attaching it to the engine shaft G, as shewn, or be
formed on or attached to the fly wheel G', the latter being in that case
arranged on the same side as the connecting rods i, i, for actuating the
valves. In the disc F I form a groove or recess F¹ extending diame-
trically across the same, in which groove or recess I fit a weight H
which is capable of sliding thercin, but is limited or restrained in its
motion by the action of a helical or other spring I attached at one end
to the weight H, and at the other end to a projection % on the disc F.
The sliding weight H carries a pin or stud on which there are mounted
the bosses n, n, of the connecting rods i, i, the opposite ends of such
rods being attached by cranks to the spindles o, o, of the valves g, g. It
will thus be seen that the disc F whilst it is employed for actuating the
valves also serves as a governor for regulating their throw to suit the speed
of the engine, the distance of the weight H from the centre of the disc F
being changed automatically by centrifugal action during the rotation of
the disc as the velocity of the engine shaft varies, so as to regulate the
point of the stroke at which the steam is cut off, and the degree of
expansion at which the engine is to be worked, according to the varying
demands upon or duty performed by the engine.
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 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 Letters is,―
First. Constructing the valve box or steam chest upon the cover of a
steam engine cylinder, substantially as and for the purpose herein-before
described and as illustrated by my Drawings.

page_text: Second. The application and use of a sliding weight for regulating.
the throw of the valves according to the speed of the engine, sub-
stantially as herein-before described and illustrated by my Drawings. .
In witness whereof, I, the said Henry Hughes, have to this my
Specification set my hand and seal, the Twelfth day of May,
One thousand eight hundred and seventy-five.