IMPROVEMENTS IN SLIDE VALVES FOR STEAM ENGINES AND OTHER PURPOSES
Year: 1857

page_text: LETTERS PATENT to Abraham Hemingway and Thomas Wheatley, botli
of Openshaw, near the City of Manchester, Engineers, for the Invention
of "IMPROVEMENTS IN SLIDE VALVES FOR STEAM ENGINES AND OTHER
PURPOSES."
Sealed the 7th July 1857, and dated the 23rd January 1857.
PROVISIONAL SPECIFICATION left by the said Abraham Hemingway and
Thomas Wheatley at the Office of the Commissioners of Patents, with
their Petition, on the 23rd January 1857.
We, ABRAHAM HEMINGWAY and THOMAS WHEATLEY, both of Openshaw,
near the City of Manchester, Engineers, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN SLIDE VALVES FOR STEAM ENGINES AND
OTHER PURPOSES," to be as follows:-
The nature of this Invention consists in the application of a second slide
valve to slide valves of the ordinary construction, for reducing the friction
on the seating and on the face of the valve.
In performing our Invention, we place the second slide valve outside the
valve chest, and connect it by a link or otherwise to the usual slide valve
within the valve chest. Both the valves may be worked by rods of the usual
construction, and the second valve is rather less in area than the original
or working valve. By this means the amount of friction on the working

page_text: valve is only equal to that due to the action of the steam, water, or other
fluid on the amount of surface equal to the difference of area between the
two valves.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Abraham Hemingway and Thomas Wheatley in the Great
Seal Patent Office on the 23rd July 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, ABRAHAM
HEMINGWAY and THOMAS WHEATLEY, both of Openshaw, near the City of
Manchester, Engineers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-third day of January, 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
us, the said Abraham Hemingway and Thomas Wheatley, Her special licence
that we, the said Abraham Hemingway and Thomas Wheatley, our executors,
administrators, and assigns, or such others as we, the said Abraham Hemingway
and Thomas Wheatley, our 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 "IMPROVEMENTS
IN SLIDE VALVES FOR STEAM ENGINES AND OTHER PURPOSES," upon the condition
(amongst others) that we, the said Abraham Hemingway and Thomas
Wheatley, our executors or administrators, by an instrument in writing under
our, or their, or one of our or 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 tho
said Letters Patent.
NOW KNOW YE, that we, the said Abraham Hemingway and Thomas
Wheatley, do hereby declare the nature of our said Invention, and in what
manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement (that is to say) :-
The nature of our Invention consists in the application of a second slide
valve to the ordinary slide valve, the said valves being of different areas, and
connected by a link or otherwise. The steam, water, or other fluid acts on

page_text: both the valves, and the second slide valve being of less area than the ordinary
slide valve, it follows that the pressure on the ordinary or working valve is
only equal to that due to the larger surface thereof.
And in order that our Invention may be fully understood and readily carried
into effect, we will proceed to describe the means pursued by us, reference
being had to the accompanying Sheet of Drawings, and to the figures and
letters marked thereon.
Fig. 1 is a longitudinal section of a locomotive engine cylinder to which
our improvements are applied; Fig. 2 is a transverse section; and Fig. 3,
a plan of the same. a is the cylinder; b, the valve chest; c, the slide valve,
of the usual construction, but furnished with a hollow recess to receive the
rounded end of the link d, which passes above through the second valve e.
The upper end of the link is provided with a nut, and a hemispherical washer
fitting in a recess in the valve e, which works on facings made on the
outside of the valve chest. The steam acts on the upper surface of the
ordinary valvo c, and on the under surface of the second valve e; and as
the valve c has a larger area than the valve e, it is evident that the pressure
on the valve c is only equal to the difference in area of the two valves
multiplied by the pressure of steam employed. The two valves are moved
simultaneously by the lever f and valve rods c¹ and e¹, or by any other con-
venient arrangement of mechanism.
The object of our Invention is to reduce the pressure on the working valve,
thereby diminishing the wearing of the valve and its seating, and to economize
the power required for working the valve to and fro on its seating. The
distance between the valves can be adjusted with the greatest accuracy by
means of the nut on the link d, so as to regulate the bearing of the valves
in their seatings.
Fig. 4 is a longitudinal section through two locomotive steam engine
cylinders, to which a modification of our Invention is applied; and Fig. 5
is a transverse section of the same. In this instance a, a, are the cylinders;
and b, the steam chest common to both; c, c, are the ordinary slide valves;
and e, e, the additional valves, the outer surfaces of which are faced and work
face to face. Each valve c is connected to one of the valves e by a link d,
and each pair of valves is worked simultaneously by the valve rods g, g, the
bridles of which are made wide enough to catch hold of both valves. Each
link d is made with a head, and by turning the link partly round the valves
c, c, can be kept in contact with their seatings, and the valves e, e, with each
other, according to the wearing of the valve seatings and of the valves. A
cotter or other agent may be employed to regulate the distance between the

page_text: valves. It is evident that by this arrangement the area of the valves c, c,
being larger than that of the valves e, e, the steam will act with greater
pressure on the valves c, c, to make them bear on their seatings.
Fig. 6 is a longitudinal, and Fig. 7 a transverse section, of a slide valve
to which another modification of our Invention is applied. The valves c and
e are connected together, as before described, by the link d, and the steam
chest b is faced on its inner surface for the valve e to work against.
When the steam is admitted into the steam chest the pressure thereof
holds the valve c on its seating, because the area of the valve c is greater
than that of the valve e, as before described. The distance between the faces
of the valves can be regulated by a box key, fitting in the recess in the head
of the link d.
If it should be desirable to admit the steam through the centre port i and
exhaust through the valve chest, we apply a small steam pipe, shewn by
dotted lines at j, through the lid of the valve chest, to allow a portion of
steam to act on the face of the valve e; by this means the pressure on the
valve c is relieved, as before described.
We wish to remark that our improvements are equally applicable to valves
used for water and other fluids under pressure.
Having thus particularly described the nature of our Invention, and several
modes of carrying the same into practical operation, we would have it under-
stood that we do not limit ourselves to the precise details given, as they may
be considerably modified without departing from the peculiar character of
our Invention; but what we do claim is, the application and use of an
additional slide valve to the ordinary slide valve, the former being of less
area than the latter, in the manner and for the purposes described.
In witness whereof, we, the said Abraham Hemingway and Thomas.
Wheatley, have hereunto set our hands and seals, this Twenty-second
day of July, in the year of our Lord One thousand eight hundred and
fifty-seven.
ABRAHAM HEMINGWAY. (L.S.)
THOMAS WHEATLEY.
(L.S.)
ABRAHAM HEMINGWAY. (L.S.)
THOMAS WHEATLEY.
(L.S.)