AN IMPROVED MODE OF RELIEVING THE SLIDE VALVES OF STEAM ENGINES PROM UNNECESSARY PRESSURE
Year: 1857

page_text: LETTERS PATENT to William Edward Newton, of the Office for Patents,
66, Chancery Lane, in the County of Middlesex, Civil Engineer, for the
Invention of "AN IMPROVED MODE OF RELIEVING THE SLIDE VALVES OF
STEAM ENGINES PROM UNNECESSARY PRESSURE."-A communication.
Sealed the 3rd Sepember 1857, and dated the 25th May 1857.
PROVISIONAL SPECIFICATION left by the said William Edward Newton
at the Office of the Commissioners of Patents, with his Petition, on the
25th May 1857.
I, WILLIAM EDWARD NEWTON, of the Office for Patents, 66, Chancery Lane,
in the County of Middlesex, Civil Engineer, do hereby declare the nature of
the said Invention for "AN IMPROVED MODE OF RELIEVING THE SLIDE VALVES OF
STEAM ENGINES FROM UNNECESSARY PRESSURE," to be as follows:-
This Invention of an improved mode of relieving the slide valves of steam
engines from unnecessary pressure consists in the construction or formation of
a steam chamber between the valve and its seat, or partly in the valve and
partly in the seat, which chamber is to be filled constantly with live steam
from the steam chest. The steam in this chamber acts in opposition to that

page_text: in the open part of the steam chest at the back of the valve, so as to balance
the valve to such an extent as is desirable, leaving only such an excess of
pressure on the back of the valve as to keep it in close contact with its seat.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Edward Newton in the Great Seal Patent Office on
the 25th November 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
EDWARD NEWTON, of the Office for Patents, 66, Chancery Lane, in the County
of Middlesex, Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fifth day of May, in the year of our Lord One
thousand eight hundred and fifty seven, in the twentieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
William Edward Newton, Her special license that I, the said William
Edward Newton, my executors, administrators, and assigns, or such others
as I, the said William Edward Newton, my executors, 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
"AN IMPROVED MODE OF RELIEVING THE SLIDE VALVES OF STEAM ENGINES FROM
UNNECESSARY PRESSURE," being a communication from abroad, upon the con-
dition (amongst others) that I, the said William Edward Newton, 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 immediately after the date
of the said Letters Patent.
NOW KNOW YE, that I, the said William Edward Newton, 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, reference being had to the Drawing hereunto annexed,
and to the letters and figures marked thereon (that is to say):-
This Invention of an improved mode of relieving the slide valves of steam
engines from unnecessary pressure consists in the construction or formation

page_text: of a steam chamber between the valve and its seat, or partly in the valve and
partly in the seat, which chamber is to be filled constantly with live steam
from the steam chest. The steam in this chamber acts in opposition to that
in the open part of the steam chest at the back of the valve, so as to balance
the valve to such an extent as is desirable, leaving only such an excess of
pressure on the back of the valve as to keep it in close contact with its seat.
In the accompanying Drawing, Fig. 1 is a longitudinal section of a slide
valve and its seat, shewing the mode of relieving, or, as it is otherwise termed,
balancing, the pressure on the valve; and Fig. 2, a transverse section of the
same in the line x, x, of Fig. 1. Similar letters of reference indicate cor-
responding parts in both Figures. A is the valve seat; a, a¹, are the steam
ports in the seat leading to the cylinder; and b, 6', are the exhaust ports, one
for each steam port a, a¹; B is the valve, which is constructed of such length
that its ends operate relatively to the ports a, a', in the same manner as any
short single slide valve, and is made with two separate cavities c, c', to convey
the exhaust steam from the ports a, a', to their respective ports b, b¹; C is
the steam chamber, which is constructed between the valve and seat to
receive the steam to balance the valve. This chamber is constructed by
making a recess in the valve seat and another in the face of the valve, so
that it is formed partly in the valve and partly in the seat, and it is made as
long as is consistent with a proper length of working face on the inner sides
of the ports b, b', and cavities c, c¹, as shewn in Figure 1, and of nearly the
full width of the valve and seat, leaving only narrow working faces d, d, on
each side of the valve. A suitable opening f is provided into that part of the
chamber C that is formed in the seat for the admission of steam to the
chamber from the steam chest. This opening may, however, be made in
the valve itself, or partly in the valve and partly in the seat.
The cavity
in the valve is made to extend nearly to the ends thereof by carrying it in
a slanting direction from the face towards the ends, as shewn at e, e, in
Figure 1. The top or back of the cavity in the valvo may be of the curved
form shewn in Fig. 1, or straight, and parallel with the face.
It is obvious that the pressure on so much of the area of the back of the
valve as is equal to the area of the chamber C will be entirely counteracted,
thus leaving only a small area open upon which the pressure on the back is
effective, which will be just about sufficient to confine it closely to its seat.
Instead of making the chamber C partly in the valve and partly in the
seat, as represented in the Drawing, it may be made entirely in the valve,
leaving the seat flush.

page_text: Having now described the Invention which has been communicated to me
by my foreign correspondent, as aforesaid, and having explained the manner
of carrying the same into effect, what I claim as the Invention secured to
me by Letters Patent, as aforesaid, is, the construction or formation of the
chamber C between the valve and its seat, as herein described, for the purpose
of receiving live steam from the steam chest to operate as and for the purpose
herein set forth.
In witness whereof, I, the said William Edward Newton, have hereunto
set my hand and seal, the Twenty-third day of November, in the year
of our Lord One thousand eight hundred and fifty-seven.
Witness,
J. W. MOFFATT,
66, Chancery Lane.
W. E. NEWTON. (L.S.)