IM- PROVEMENTS IN SLIDE VALVES
Year: 1878

page_text: LETTERS PATENT to Nathaniel Clayton and Joseph Shuttleworth, both of
Lincoln, in the County of Lincoln, Engineers, for the Invention of "IM-
PROVEMENTS IN SLIDE VALVES."
Sealed the 10th December 1878, and dated the 6th July 1878.
PROVISIONAL SPECIFICATION left by the said Nathaniel Clayton and
Joseph Shuttleworth at the Office of the Commissioners of Patents on the
6th July 1878. -
NATHANIEL CLAYTON and JOSEPH SHUTTLEWORTH, both of Lincoln, in the
County of Lincoln, Engineers. IMPROVEMENTS IN SLIDE VALVES."
[t
Our Invention relates to improvements in slide valves for portable, traction,
stationary, and other engines, whereby the defects inherent in slide valves of the
ordinary construction are obviated or diminished.
The mode of construction usually adopted in steam engine slide valves is to makė
the surface which fits to the steam ports face a perfectly level plane thickened up
sufficiently to allow of its being recessed for the escape of the expended steam from
the cylinder, and also for attaching the rod or other gear by which the valve is
moved.
As the valve rod is attached at a considerable distance from the point of impact
the force exerted to slide the valve necessarily produces a tilting or rolling motion,
which wears the face from a flat to a convex form, and so causes a wasteful escape
of steam.
Now our Invention has for its object remedying the defect before mentioned, and
this object is effected by constructing the slide valve with two faces placed at an
angle to each other. We, by preference, adopt a right angle, but do not confine
ourselves to any particular angle.

page_text: The joint width of the two faces is of the same superficial area as the valve
ordinarily used, and they fit over corresponding faces on the cylinder containing the
steam ports.
The orifice to receive the valve rod is placed in or near the centre of the right-
angled triangle described by the end of the valve, this point being practically the
centre of adhesion; hence, the cause which produces the tilting or rolling motion
above referred to is removed, and consequently the valve will retain indefinitely a
steam-tight face.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Nathaniel Clayton and Joseph Shuttleworth in the Great Seal Patent
Office on the 31st December 1878.
NATHANIEL CLAYTON and JOSEPH SHUTTLEWORTH, both of Lincoln, in the
County of Lincoln, Engineers. "IMPROVEMENTS IN SLIDE VALVES."
Our said Invention relates to improvements in slide valves for portable, traction,
stationary, and other engines, whereby the defects inherent in slide valves of the
ordinary construction are obviated or diminished.
The mode of construction usually adopted in steam engine slide valves is to
make the surface which fits the steam port face a perfectly level plane, thickened
up sufficiently to allow of its being recessed for the escape of the expended steam
from the cylinder, and also for attaching the rod or other gear by which the valve
is moved.
As the valve rod is attached at a considerable distance from the point of impact
the force exerted to slide the valve necessarily produces a tilting or rolling motion,
which wears the face from a flat to a convex form, and so causes a wasteful escape
of steam.
Now our said Invention has for its object remedying the defect before mentioned,
and this object is effected by constructing the slide valve with two faces placed at
an angle the one to the other. We, by preference, adopt a right angle, but do not
confine ourselves to any particular angle.
The joint width of the two faces is of the same superficial area as the valve
ordinarily used, and they fit over corresponding faces on the cylinder containing
the steam ports.
The orifice for the reception of the valve rod is placed at or near the centre of
the triangle formed by the end of the valve, this point being practically the centre
of adhesion; hence, the cause which produces the tilting or rolling motion above
referred to is removed, and consequently the valve will retain indefinitely a steam-
tight face.
And in order that our said Invention may be fully understood, we shall now.
proceed more particularly to describe the same, and for that purpose shall refer to
the several Figures on the annexed Sheet of Drawings, the same letters of
reference indicating corresponding parts in both the Figures.
Figure 1 of the accompanying Drawings represents a transverse section of a
portion of a steam cylinder and steam chest with the slide valve fitted in the
latter, and constructed and arranged according to our said Invention; Figure 2 is a
longitudinal section of the same corresponding to Figure 1.
A is the steam chest; B is the cylinder; and C, the face of the latter, having
opening therein the steam ports a, a, and the exhaust port b.
In lieu of making the port face O a level plane surface, as heretofore, I construct
it of an angular recessed shape, as shewn clearly at c, d (Figure 1), the two
portions c, d, forming together, by preference, a right angle, as shewn, and I
construct the slide valve D with 2 faces e, f, at an angle the one to the other
corresponding to that of the two portions c, d, of the port face C, to which the
valve is adapted, the valve rod g being attached to the valve near the centre of the
triangle formed by the end of the latter.
By this construction of the valve, and arrangement of the valve and valve rod,
the defects herein-before referred to, inherent to the ordinary method, are entirely
obviated or greatly diminished.
The Invention has also the further advantage that by the triangular form of the
valve the superficial area exposed to pressure is reduced, and the weight is pro-
portionately diminished on each rubbing surface.
Having now described and particularly ascertained the nature of our said
Invention, and the manner in which the same is or may be used or carried into

page_text: effect, we would observe in conclusion that what we consider to be novel and original,
and therefore claim as the Invention secured to us by the herein-before in part
recited Letters Patent is, constructing slide valves with two working faces, the one
at an angle to the other, substantially as and for the purpose herein-before
described.
In witness whereof, we, the said Nathaniel Clayton and Joseph Shuttleworth,
have to this our Specification set our hands and seals, this Thirty-first day
of December, One thousand eight hundred and seventy-eight.
NATHANIEL CLAYTON. (L.S.)
JOSEPH SHUTTLEWORTH. (L.S.)