AN IMPROVED EQUILIBRIUM SLIDE VALVE FOR STEAM ENGINES
Year: 1867

page_text: LETTERS PATENT to Richard Roberts, of Pontypridd, in the County of
Glamorgan, Engineer, and Philip Williams, of the Firm of Morgan,
Williams, and Company, of the same Place, Engineers, for the Invention
PROVISIONAL SPECIFICATION left by the said Richard Roberts and
Philip Williams, at the Office of the Commissioners of Patents, with
their Petition, on the 12th December 1867.
We, RICHARD ROBERTS, of Pontypridd, in the County of Glamorgan,
Engineer, and PHILIP WILLIAMS, of the Firm of Morgan, Williams, and
Company, of the same Place, Engineers, do hereby declare the nature of the
said Invention for "AN IMPROVED EQUILIBRIUM SLIDE VALVE FOR STEAM
ENGINES," to be as follows:-
The object of this Invention is to take off the pressure from the back of
the slide valve by means of a self-adjusting plate on the back of the same;
the valve being entirely hollow to avoid any pressure of the steam on its
back.
In carrying out this Invention a hollow cylinder is cast in one piece with
the plate on back of the valve, the cylinder is turned outside and fitted into a

page_text: packing box in the steam chest cover, the cylinder is made a little less in area
than the valve to allow only sufficient pressure to keep the valve to the face of
the steam ports. The plate is nicely fitted endways in the steam chest to prevent
oscillation by the motion of the valve. The cylinder works through a gland
of packing box on steam chest cover. There are two-set pins to prevent the
valve from rising off the face of steam ports when the engine is being reversed.
A great advantage will be derived from slide valves constructed on this
principle in winding engines for collieries, inasmuch as the engine will be
quite easily managed and reversed by the engine driver, which is an important
point in winding engines for collieries, where lives depend on the exact point
at which the engine is to be stopped. This principle can also be easily
adapted to locomotive engines for either inside or outside cylinders, and to
take away all the friction from the slide valves; thereby effecting a saving in
the power of the engine of nearly one-third, especially when working the
steam expansively, and consequently is a considerable saving in fuel. Another
very important advantage to be observed is the very simple construction of
this valve; once fitted properly there is nothing to get out of order, as the faces
will wear together and remain effective. This principle can also be applied to
regulating valves for steam engines.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Richard Roberts and Philip Williams in the Great Seal
Patent Office on the 12th June 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, RICHARD
ROBERTS, of Pontypridd, in the County of Glamorgan, Engineer, and PHILIP
WILLIAMS, of the Firm of Morgan, Williams, and Company, of the same
Place, Engineers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twelfth day of December, in the year of our
Lord One thousand eight hundred and sixty-seven, in the thirty-first year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
us, the said Richard Roberts, and Philip Williams, Her special licence that
we, the said Richard Roberts and Philip Williams, our executors, adminis-
trators, and assigns, or such others as we, the said Richard Roberts and
Philip Williams, 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,

page_text: the Channel Islands, and Isle of Man, an Invention for "AN IMPROVED
EQUILIBRIUM SLIDE VALVE -FOR STEAM ENGINES," upon the condition (amongst
others) that we, the said Richard Roberts and Philip Williams, our executors
or administrators, by an instrument in writing under our, 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 we, the said Richard Roberts and Philip Williams,
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 in writing, and on reference to the
accompanying Sheet of Drawings, that is to say:-
The object of this Invention is to take off the pressure from the back of
the slide valve by means of a self-adjusting plate on the back of the same,
the valve being entirely hollow to avoid any pressure of the steam on its
back.
..
In carrying out this Invention a hollow cylinder is cast in one piece with
the plate on back of the valve, the cylinder is turned outside and fitted
into a packing box in the steam chest cover, the cylinder is made a little less
in area than the valve to allow only sufficient pressure to keep the valve to
the face of the steam ports. The plate is nicely fitted endways in the steam
chest to prevent oscillation by the motion of the valve. The cylinder works
through a gland of packing box on steam chest cover. There are two set
pins to prevent the valve from rising off the face of steam ports when the engine
is being reversed. A great advantage will be derived from slide valves-con-
structed on this principle in winding engines for collieries, inasmuch as the
engine will be quite easily managed and reversed by the engine driver, which
is an important point in winding engines for collieries, where lives.depend on
the exact point at which the engine is to be stopped. This principle can also
be easily adapted to locomotive engines for either inside or outside cylinders,
and take away all the friction from the slide valves, thereby effecting a saving
in the power of the engine of nearly one-third, especially when working the
steam expansively, and consequently is a considerable saving in fuel. Another
very important advantage to be observed is the very simple construction of
this valve; once fitted properly there is nothing to get out of order, as the
faces will wear together and remain effective. This principle can also be
applied to regulating valves for steam engines.

page_text: Such being the nature and object of our said Invention for "An Improved
Equilibrium Slide Valve for Steam Engines," we will now proceed to describe
more in detail the manner in which the same is to be or may be performed or
carried into practical effect, and in order that the same may be distinctly
understood we have annexed hereunto a Sheet of Drawings illustrative thereof,
and have marked the same with figures and letters of reference corresponding
with those in the following explanation thereof, that is to say:-
In the annexed Drawing Figure 1 is a longitudinal section through a steami
cylinder and valve box or steam chest, showing the application of our improved
equilibrium slide valve thereto.
a, a, is the steam cylinder; b, b, the valve box or steam chest; and c, c, the
valve. The form of this valve is particularly shown in face view at Figure 2,
and back view at Figure 3.
Figure 4 is a section through the line A, B, in Figure 2, and Figure 5 is a
section through the line C, D, in Figure 3.
d, d, is an equilibrium plate placed on the back of the valve and having a
cylinder e, e, cast in one piece with it, as seen in the plan view of the equilibrium
plate Figure 6. The cylinder e, e, is turned outside and fitted steam-tight
into a stuffing box f, f, in the cover of the steam chest; 9, 9, are two set
screws to prevent the plate from rising off the back of the valve; h, h, is the
valve spindle; and i, i, the stuffing boxes through which it passes.
Having now described the nature and object of our said Invention for "An
Improved Equilibrium Slide Valve for Steam Engines," together with the
manner in which the same is to be or may be performed or carried into
practical effect, we would remark in conclusion that we claim as our Invention
the construction of an equilibrium slide valve substantially in the manner
herein-before described and represented on the Drawing annexed without
confining ourselves to the precise details or proportions of the various
parts.
In witness whereof, we, the said Richard Roberts and Philip Williams
have hereunto set our hands and seals, this Tenth day of June
in the year of our Lord One thousand eight hundred and sixty