IMPROVEMENTS IN VALVES AND PORTS FOR COMPOUND STEAM ENGINES."
Year: 1874

page_text: LETTERS PATENT to John Newrick Coxon, of Hackney, in the
County of Middlesex, Engineer, for the Invention of "IMPROVEMENTS
IN VALVES AND PORTS FOR COMPOUND STEAM ENGINES."
PROVISIONAL SPECIFICATION left by the said John Newrick Coxon
at the Office of the Commissioners of Patents, with his Petition,
on the 24th June 1874.
I, JOHN NEWRICK COXON, of Hackney, in the County of Middlesex,
Engineer, do hereby declare the nature of the said Invention for "Im-
PROVEMENTS IN VALVES AND PORTS FOR COMPOUND STEAM ENGINES," to be as
follows (that is to say) :-
This Invention relates to improvements in valves and ports for
compound steam engines, either stationary, locomotive, or marine, and
may be applied to existing compound engines at a trifling cost. It is
particularly applicable where the cranks are placed at a relative angle
of forty-five degrees, or nearly so.

page_text: According to my Invention the steam from the high-pressure cylinder
instead of being conducted away by the ordinary exhaust port is
conveyed right through the valve, and through the intermediate division
plate direct into the steam chamber of the expansive cylinder, for which
purpose two ports are formed in the intermediate plate directly opposite
those in the cylinders.
When the steam has entered the steam chamber of the expansive
cylinder its admission to that cylinder, which is provided with ordinary
ports and exhaust, is governed either by an ordinary valve or by a valvo
in which the exhaust port is carried right through, communicating on
the one side with the ports of the cylinder, and on the other with the
ports in the intermediate plate.
The opening and closing of the ports in the intermediate plate may
also be governed by a plate or valve working on the back thereof, and
actuated by a separate excentric, or otherwise.
At the point in the back stroke of the high-pressure piston, where
the communication between the two cylinders is cut off, and where
therefore the back pressure commences I provide either for communi-
cation with the condenser to form a vacuum or for compression and
reaction of the steam remaining in the cylinder.
For obtaining the vacuum I put the starting valve into communication
with the condenser, and govern the action of the valve by an excentric,
and when the valve is wanted for starting I throw the excentric out of
gear by a link motion or by other suitable means.
When compression of the back steam is preferred I compress into any
suitable reservoir or into the ordinary steam jacket surrounding the
cylinder, which however I divide in the middle by a partition plate, cach
half communicating with one end of the cylinder, the steam thus
compressed of course reacts at the return stroke.

page_text: filed by the said John Newrick Coxon in the Great Seal Patent
Office on the 24th December 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
NEWRICK COXON, of Hackney, in the County of Middlesex, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fourth day of June, in the year of
our Lord One thousand eight hundred and seventy-four, in the thirty-
cighth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said John Newrick Coxon, Her special
license that I, the said John Newrick Coxon, my executors, adminis-
trators, and assigns, or such others as I, the said John Newrick
Coxon, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times there-
after during the term therein expressed, should and lawfully might
make, usc, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Inven-
tion for "IMPROVEMENTS IN VALVES AND PORTS FOR COMPOUND STEAM ENGINES,"
upon the condition (amongst others) that I, the said John Newrick
Coxon, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, 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 John Newrick Coxon, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof, that is to say :--
This Invention relates to improvements in valves and ports for
compound steam engines, either stationary, locomotive, or marine, and
may be applied to existing compound engines at a comparatively trifling
cost. It is particularly applicable where the cranks are placed at a
relative angle of 90 degrees, or nearly so,

page_text: And in order that my Invention may be clearly understood and
readily carried into effect, I will proceed to describe the same with
the aid of the accompanying Drawings, reference being had to the
letters and figures marked thereon.
According to my Invention the steam from the high-pressure cylinder
instead of being conducted away by the ordinary exhaust port is carried
right through the valve and thence direct into the steam chamber of the
expansion cylinder; and in cases where the valves of both cylinders are
between the cylinders the steam after passing through the valve is
carried direct through the intermediate or division plate.
Figures 1 and 2 of the accompanying Drawings illustrate a pair of
cylinders of a compound engine with the improvements applied, the
valves being between the cylinders. Figure 1 is a vertical central
section; and Figure 2 a horizontal section at the line a, b, Figure 1.
A is the high-pressure cylinder; B, the low-pressure cylinder; C is the
intermediate plate with ports c, c; D is my improved valve with
ports d, d, passing right through and communicating on the one side
with the ports of the cylinder, and on the other side with the ports in
the intermediate plate, the valve being also provided with two faces, the
one working on the face of the cylinder and the other on the inter-
mediate plate.
It will also be observed that the ordinary exhaust port of the high-
pressure cylinder is closed. The steam from the low-pressure cylinder
passes through the valve D, thence through the intermediate plate into
the steam chamber of the low-pressure cylinder, its admission to which
is governed by an ordinary valve E. The plate F working on the back
of the intermediate plate C is to prevent the steam entering the steam
chamber from one side of the high-pressure cylinder from passing back
into the other end. This plate F is worked by a separate eccentric, as
shewn in Figures 1 and 2, when the engines are constructed to work
both forwards and backwards, but when the engine is to work only in
one direction the plate F may be connected with the valve of the low-
pressure cylinder, and both be worked by one and the same eccentric, as
shewn at Figure 3, which is also a vertical central section. The steam
left in the cylinder at the back of the piston is either compressed into a
suitable reservoir or conducted to the condenser, as shewn at Figures 1
and 2. It is compressed into an ordinary steam jacket G surrounding

page_text: the cylinder, the steam being admitted thereto through ports g, g, and
the jacket being divided at the middle by a division plate, so as to form
an independent reservoir communicating with each end of the cylinder.
Figures 4 and 5 illustrate a method of conveying the back steam to
the condenser, Figure 4 being a vertical central section, and Figure 5 a
sectional plan at line h, j, Figure 4. According to this method I cast
an exhaust port H in the division plate C, and instead of the plate F
employ a valve I, which, in addition to performing the duties of the
plate F serves also to convey the back steam by way of the port H to
the condenser. Where there is not sufficient room between the faces of
the two cylinders for the division plate with exhaust port, and for the
valve in addition (as illustrated at Figure 4), and where it is still
necessary to convey
the back steam to the condenser, I make use of the
starting valve (see J, Figure 2), which I work by an eccentric, and
cause the same to open communication with the condenser at the
suitable moments.
When the valve is required for starting it may be thrown out of gear
with the eccentric by a link or other suitable motion.
When the valves are not both between the cylinders only a slight
modification from the above described arrangement is necessary.
Figures 6 and 7 illustrate my improvements applied where the valve
of the cylinder is on the outside, Figure 6 being a vertical central
section, and Figure 7 a sectional plan at the line p, 1, Figure 6. The
ordinary cover of the steam chamber is removed, and a steam chamber K
substituted, having cast in it an exhaust port and ports k', ², which
ports are governed by an ordinary valve I. The exhaust port of the
cylinder is closed, as in the previous case, and my valve applied. The
expending steam is conveyed from the chamber K to the L, P, cylinder,
and the back steam is conveyed by the exhaust port / to the condenser.
When, with this form of engine, it is desired not to convey the back
steam to the condenser, then the exhaust port k is dispensed with, and a
plate used instead of the valve I, as in the form shewn in Figure 1, the
back steam being either compressed into a reservoir or allowed to blow
off into the atmosphere. When, in the case of an engine constructed to
run one way only, it is desired to convey the back steam into the condenser
this may be accomplished either by the methods described already or
by having the exhaust cavity of the valve of the L, P, cylinder to pass

page_text: right through the valve and a corresponding opening in the plate F (sec
Figure 3).
.
By my arrangement of valves and ports I introduce the steam into the
expansive cylinder just at the moment when the dead point has been
turned, thereby obtaining very great effective power. Nearly the whole
of the expansive power of the steam is also utilized.
In the case of non-condensing compound engines the exhaust steam
from the low-pressure cylinder may when desired be compressed into a
suitable reservoir instead of being allowed to blow off into the
atmosphere.
Figures 8, 9, 10, and 11 illustrate my valve in detail, Figure 8 being
a longitudinal section on the centre line; Figure 9 a transverse section
also on the centre line; Figure 10, a plan with the frame removed; and
Figure 11 an underneath plan of the frame. D is the main body of the
valve, having cast in it ports d and recesses d¹ for the reception of the
frames d² and d³ and the elastic packing d. The frame & rests in the
bottom of the recess d', and has cast on its side projections to allow of
steam getting in at the back. The elastic packing d' comes between the
two frames, and the steam entering at the back of the frame d² presses
the body of the valve and the frames apart, thus forcing their faces up
to the faces of the cylinder and partition plate, against which they work,
and thus cause them to work steam-tight.
Having thus particularly described and ascertained the nature of this
my said Invention, and the manner in which the same is to or may be
performed, I claim as my Invention to be secured by the herein-before a
in part recited Letters Patent, the improvements in valves and ports
for compound steam engines; substantially as herein-before set forth and
described and illustrated in the accompanying Drawings.
In witness whereof, I, the said John Newrick Coxon, have here-
unto set my hand and seal, this Twenty-fourth day of December, {
in the year of our Lord One thousand eight hundred and seventy-
four.