IMPROVEMENTS IN ESCAPE OR RELIEF VALVES TO THE CYLINDERS OF MARINE AND OTHER STEAM ENGINES
Year: 1863

page_text: LETTERS PATENT to John Penn, of Greenwich, in the County of Kent,
for the Invention of "IMPROVEMENTS IN ESCAPE OR RELIEF VALVES TO THE
CYLINDERS OF MARINE AND OTHER STEAM ENGINES."
Sealed the 12th May 1863, and dated the 28th February 1863.
PROVISIONAL SPECIFICATION left by the said John Penn at the
Office of the Commissioners of Patents, with his Petition, on the
28th February 1863.
I, JOHN PENN, of Greenwich, in the County of Kent, do hereby declare
the nature of the Invention for "IMPROVEMENTS IN ESCAPE OR RELIEF VALVES
TO THE CYLINDERS OF MARINE AND OTHER STEAM ENGINES," to be as follows:-
This Invention has for its object improvements in escape or relief valves to
the cylinders of marine and other steam engines. Escape or relief valves are
now commonly fitted to the cylinders of marine and other engines to allow of
the escape of water should any be carried over from the boilers into the
cylinders with the steam, and these valves hitherto have had to be loaded by
weights or springs to an extent greatly exceeding the pressure of the steam in
the boiler, to prevent the inconvenience of the steam escaping into the engine
room, more especially when the engines are worked expansively by the link
motion or suddenly reversed, as in these cases the steam becomes compressed
or jammed to a considerable extent towards the end of the stroke by the lap or
cover on the slide valve, producing an undue and severe strain on the
machinery, particularly in engines where the slide valves are prevented coming

page_text: off their faces by being fitted with packing on the back to relieve the pressure
on the faces.
According to my Invention I apply, instead of weights and springs, the
pressure of the steam to keep the escape or relief valves in their seats; for
this purpose I place the valves, enclosed in cases, on any convenient part of
the cylinders sufficiently high for any water to pass by means of pipes into a
separator in the main steam pipe of the engine, or to the main steam pipe
itself, where the position of the latter will admit of the arrangement. It will
be seen that the valves are kept in their seats by the difference between the
pressure of steam in the main steam pipe and the cylinder, and also in con-
sequence of the difference of area between the outer and inner surfaces of
the valve.
In this arrangement there is so little weight tending to keep the valve on
its seat that it will frequently open in consequence of the compression of
steam in working expansively by the link motion, or arising from suddenly
reversing the engines, and no strain can come on to any part of the machinery
beyond that resulting from the pressure of steam in the boiler.
The ordinary relief or escape valves, on the other hand, are often rendered
inoperative by being overloaded to prevent the steam escaping into the engine
room, and this is the cause of their frequently sticking fast. It will be seen
that by my arrangement the objection of working engines expansively by the
link motion, and which now causes the steam to become much compressed at
each end of the stroke, is removed, the steam as soon as the compression
commences passing back into the steam pipe without any loss; all accidents
from scalding will also be avoided.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Penn in the Great Seal Patent Office on the
28th August 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
PENN, of Greenwich, in the County of Kent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-eighth day of February, in the year of our
Lord One thousand eight hundred and sixty-three, in the twenty-sixth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said John Penn, Her special licence that I, the said John Penn,
my executors, administrators, and assigns, or such others as I, the said

page_text: John Penn, 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,
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 ESCAPE OR RELIEF VALVES TO THE CYLINDERS OF MARINE AND
OTHER STEAM ENGINES," upon the condition (amongst others) that I, the said
John Penn, 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 Penn, do hereby declare the
5 nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:-
This Invention has for its object improvements in escape or relief valves to
the cylinders of marine and other steam engines. Escape or relief valves are
now commonly fitted to the cylinders of marine and other engines to allow of
the escape of water should any be carried over from the boilers or otherwise
get into the cylinders, and these valves hitherto have had to be loaded by
weights or springs to an extent greatly exceeding the pressure of the steam in
the boiler, to prevent the inconvenience of the steam escaping into the engine
5 room, more especially when the engines are worked expansively by the link
motion or suddenly reversed, as in these cases the steam becomes compressed
or jammed to a considerable extent towards the end of the stroke by the lap or
cover on the slide valve, producing an undue and severe strain on the
machinery, particularly in engines where the slide valves are prevented coming
o off their faces by being fitted with packing on the back to relieve the pressure
on the faces.
According to my Invention I apply, instead of weights and springs, the
pressure of the steam to keep the escape or relief valves in their seats; for
this purpose I place the valves, enclosed in cases, on any convenient part of
the cylinders sufficiently high for any water to pass by means of pipes into a
separator in the main steam pipe of the engine, or to the main steam pipe
itself, where the position of the latter will admit of the arrangement. It will
be seen that the valves are kept in their seats by the difference between the
pressure of steam in the main steam pipe and the cylinder, and also in con-

page_text: sequence of the difference of area between the outer and inner surfaces of
the valve.
In this arrangement there is so little weight tending to keep the valve on
its seat that it will frequently open in consequence of the compression of
steam in working expansively by the link motion, or arising from suddenly
reversing the engines, and no strain can come on to any part of the machinery
beyond that resulting from the pressure of steam in the boiler.
The ordinary relief or escape valves, on the other hand, are often rendered.
inoperative by being overloaded to prevent the steam escaping into the engine
room, and this is the cause of their frequently sticking fast. It will be seen
that by my arrangement the objection of working engines expansively by the
link motion, and which now causes the steam to become much compressed at
each end of the stroke, is removed, the steam as soon as the compression com-
mences passing back into the steam pipe without any loss; all accidents from
scalding will also be avoided.
Having thus stated the nature of my Invention, I will proceed more fully
to describe the manner of performing the same.
DESCRIPTION OF THE DRAWINGS.
Figure 1 shows a section of a steam cylinder of a double-trunk engine;
Figure 2 shows a plan, partly in section, of a pair of such steam cylinders and
Figure 3 shows an end elevation, partly in section, of the parts shewn in
Figure 2. In each of these Figures the arrangement or combination of the
parts employed for carrying out my improvements is colored.
A, A, are the steam cylinders; B is the main steam pipe for supplying
steam thereto from the boilers; C is a chamber, into which the steam is con-
ducted from the boilers; this chamber is divided to some extent by the
partition c, under which the steam passes before it enters into the main steam
pipe B, as is indicated by the arrows; D, D, are passages from the two ends
of each steam cylinder A, which communicate with valve boxes E, E, in
which are valves F, F, which are constantly pressed towards their seats by
steam acting on their outer surfaces. The valve boxes E, E, are connected to
each other and to the chamber C of the main steam pipe by pipes G, G,
hence when water is driven through any of the passages D, D, from the steam
cylinders, it will overcome the pressure of the steam acting on the valves, and
will pass away by the pipes G to the chamber C, where provision is made for
drawing off the water.
Figure 4 shows a plan, Figure 5 a side elevation, and Figure 6 a trans-
verse section of a pair of inverted steam cylinders working with ordinary

page_text: piston rods, and arranged for driving a screw, or it may be other shaft. In
these Figures similar arrangements of escape or relief valve apparatus are
shewn and marked with like letters of reference to those already described.
I would here remark that an engineer will, from the above description of
the nature of my Invention, and the manner of applying the same to the two
classes of steam engines shown in the Drawings, readily arrange escape or
relief valves and apparatus according to my Invention, and apply the same to
other constructions of steam engines.
Having thus described the nature of my Invention, and the manner of per-
forming the same, I would have it understood that what I claim is, the mode
herein described of arranging the escape or relief valve apparatus of marine
and other steam engines.
In witness whereof, I, the said John Penn, have hereunto set my hand
and seal, this Eighteenth day of August, in the year of our Lord One
thousand eight hundred and sixty-three.
JOHN PENN. (L.S.)