IMPROVED MEANS FOR RELIEVING THE SLIDE VALVES OP STEAM ENGINES OF UNNECESSARY PRESSURE
Year: 1860

page_text: LETTERS PATENT to Alfred Vincent Newton, of the Office for Patents,
66, Chancery Lane, in the County of Middlesex, Mechanical Draughts-
man, for the Invention of "IMPROVED MEANS FOR RELIEVING THE SLIDE
VALVES OP STEAM ENGINES OF UNNECESSARY PRESSURE."-A communication
from abroad by David Stoddart, of the City of San Francisco, State of
California, United States of America.
Sealed the 11th December 1860, and dated the 24th July 1860.
PROVISIONAL SPECIFICATION left by the said Alfred Vincent Newton at
the Office of the Commissioners of Patents, with his Petition, on the
24th July 1860.
I, ALFRED VINCENT NEWTON, of the Office for Patents, 66, Chancery Lane,
in the County of Middlesex, Mechanical Draughtsman, do hereby declare the
nature of the said Invention for "IMPROVED MEANS FOR RELIEVING THE SLIDE
VALVES OF STEAM ENGINES OF UNNECESSARY PRESSURE," to be as follows:-
This Invention relates to the employment in combination with a slide valve
of a stationary rigid plate, which is fitted to the back of the valve, and extends
across its full width. The contact face of this plate is recessed to allow access
of atmospheric air to the covered portion of the back of the valve. The
stationary plate which may be termed the balance plate is attached to the cover

page_text: of the steam chest by a flexible plate of copper or other metal, which is fitted
and secured steam-tight, around the margin of a cavity, provided in the cover of
the steam chest, and having free communication with the atmosphere; the said
flexible plate keeping the stiff plate in contact with the valve in such a manner
as to protect it as much as desirable from the pressure of steam. In con-
nection with these plates is a spring carried by a hollow screw, which projects
down into the steam chest and serves to connect the balance plate and flexible
plate together, and also admit air to the under side of the balance plate.
This screw may if required be closed by a cock. Set screws are also provided,
which are capable of adjustment without opening the steam chest to
regulate the pressure to be exercised by the spring in keeping the balance
plate to its work, and to prevent injury to the valve or plates in case of the
valve becoming unseated.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Alfred Vincent Newton in the Great Seal Patent Office on
the 24th January 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALFRED
VINCENT NEWTON, of the Office for Patents, 66, Chancery Lane, in the County
of Middlesex, Mechanical Draughtsman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fourth day of July, in the year of our Lord
One thousand eight hundred and sixty, in the twenty-fourth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Alfred Vincent Newton, Her special license that I, the said Alfred Vincent
Newton, my executors, administrators, and assigns, or such others as I, the
said Alfred Vincent 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
"IMPROVED MEANS FOR RELIEVING THE SLIDE VALVES OF STEAK ENGINES
OP UNNECESSARY PRESSURE," being a communication from abroad upon the
condition (amongst others) that I, the said Alfred Vincent 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

page_text: 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 Alfred Vincent Newton, do hereby declare
the nature of the said Invention, and in what manner the same is to bo
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 as communicated to me by my foreign correspondent relates
to the employment, in combination with a slide valve, of a stationary rigid
plate fitted to a flat surface on the back of the valve parallel with the face thereof,
and attached to the back or cover of the steam chest by a flexible plate, which
is fitted and secured steam-tight around the margin of a cavity provided in the
back or cover of the steam chest in free communication with the atmosphere.
It also relates to the employment in connection with the so applied plates of a
spring and set screws so applied as to be capable of adjustment without opening
the steam chest.
In the accompanying Drawing, Fig. 1 is a central longitudinal section
of a steam chest and slide valve constructed according to this Invention ;
Fig. 2 is a transverse section; and Fig. 3 a plan of the same. Similar
letters of reference indicate corresponding parts in the several Figures.
A is the steam chest; A', its cover, and a, a, the valve seat; B is the slide
valve, which does not differ from the short "D" or "three port" valves ordi-
narily used, except that it has its back planed or otherwise made perfectly flat
and parallel with its face; B' is the valve stem; C is the stationary plate,
which may be termed the "balance plate" fitted to the back of the valve,
This plate extends all across the valve, and its width in a direction lengthwise
of the valve is equal to the distance between the two steam ports 8, 8, with
the addition of half the width of one of said ports; E is the flexible plate
made of copper or other moderately flexible metal, which attaches the plate C
to the back of the steam chest. This plate E is secured in place by having its
margin clamped between the body of the steam chest and the cover A¹; b, b,
is the cavity in the steam chest cover arranged in the centre thereof, and made
of circular form and having a central opening d communicating with the
atmosphere. The area of this cavity is greater than the area of the balance
plate. The portion of the inner face of the cover A' surrounding the cavity b, b,
is flat and parallel with the valve seat; F is a rigid flat circular plate of an
area smaller than the area of the balance plate C applied at the back of the

page_text: flexible plate E, and secured thereto by a screw G, which passes through the
centres of both those plates, and screws into the centre of the balance plate C,
and so serves to attach the three plates securely together. The top of the
head of this screw G passes through the opening d to the exterior of the cover.
The balance plate C and the flexible plate E are only in steam-tight contact on
a small surface surrounding the screw G, the balance plate having its upper
surface bevelled toward the edges, as shewn in Figures 1 and 2 to allow steam
to enter between it and the flexible plate. The screw G has a central opening
e right through it for the purpose of establishing communication between a
cavity in the bottom of the balance plate C, and the atmosphere; H is a
spring having an opening in the centre, which fits the top of the head of the
screw G. This spring is held down upon a shoulder on the head of the said
screw by means of two screws I, I, which screw into the steam chest cover A',
J, J, are screws projecting through the steam chest cover on opposite sides of
the screw G. The top or back of the balance plate and the inner surface of
the flexible plate E are both exposed to the pressure of steam, which keeps the
flexible plate E in contact with the part of the cover A', surrounding the
cavity b, b, but so far as the balance plate is concerned is only effective on the
part of the plate E, that is opposite the cavity 6, 6, and this cavity being
larger than the area of the balance plate there is a tendency to raise the
said plate from the valve. The plate F gives the necessary stiffness to the
central portion of the plate E, but leaves the portion between it and the
edges of the cavity b, b, flexible enough to enable the balance plate to
accommodate itself to the back of the slido valve under all circumstances.
The screws J, J, are set with their points very nearly in contact with the back
of the plate F to prevent injury to the valve or plates in case of the valve
becoming unseated. The said screws are also serviceable in the first use of a
new valve when they should be screwed down to hold the valve firmly to its
seat till the faces have worn smooth and steam tight. The opening e in the
screw G serves not only to relieve from pressure the part of the back of the valve
which is covered by the balance plate, but also for the escape to the atmosphere
of any leakage that might tako place between the valve and balance plate, and,
provides the means for showing the condition of the said plate. The screw G
may be fitted with a stop cock or valve to close the opening e; for by closing
this cock in case any part of the means for the relief of pressure should get out of
repair the valve is at once and without the necessity of stopping the engine
made to work as a common slide valve.
Having now set forth the nature of the Invention of "Improved Means for

page_text: Relieving the Slide Valves of Steam Engines of unnecessary Pressure," as
communicated to me from abroad, and having explained the manner of carrying
the same into effect, I wish it to be understood that under the above in part
recited Letters Patent I claim the adaptation to the steam chests of steam
engines of the means above described for relieving the slide valves contained
therein of unnecessary pressure.
In witness whereof, I, the said Alfred Vincent Newton, have hereunto
set my hand and seal, the Twenty-fourth day of January, in the year
of our Lord One thousand eight hundred and sixty-one.
Witness,
J. W. MOFFATT,
66, Chancery Lane.
A. V. NEWTON. (L.S.)