IMPROVEMENTS IN VALVE APPARATUS FOR REGULATING THE FLOW OF STEAM & OTHER FLUIDS
Year: 1860

page_text: PROVISIONAL SPECIFICATION left by William Clark at the Office of the
Commissioners of Patents, with his Petition, on the 19th July 1860.
-A communication from abroad by Messrs. Charles Auguste Riff,
Engineer, and Antoine Laudenmüller, Mechanician, of Paris, in the
Empire of France.
I, WILLIAM CLARK, of 53, Chancery Lane, in the County of Middlesex,
Engineer and Patent Agent, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN VALVE APPARATUS FOR REGULATING THE FLOW OF
STEAM & OTHER FLUIDS," to be follows:-
This Invention consists in substituting for slide valves of locomotives and
other steam engines a double piston, which suffers no friction due to the pres-
sure of steam. I have shown this new arrangement in the annexed Drawings,
in which Fig. 1 is a longitudinal section through the axis of the two cylinders;
Fig. 2 is a transverse section through A, B; Fig. 3 is a longitudinal section
of the cylinder of the piston valve through C, D, and side view of inlet ports;
Fig. 4 is a section of the same, shewing the eduction passages. In all the
Figures the same letters represent the same parts seen in the different
views.
a, ordinary motive cylinder; b, cylinder of the piston valve; it may be dis-
posed on either side of the cylinder u, and be cast in one with it, or may be
connected thereto; c, double piston valve. This valve is composed of two pistons
fixed on the same rod, and constructed in same manner as those employed at
present in the motive cylinders of locomotives. d, induction ports; e, eduction

page_text: passages; and f, opening for the introduction of steam into the cylinder of the
piston valve; this opening is formed between the two pistons c; g, two plates
with stuffing boxes closing both ends of the cylinder of the piston valve. The
steam of the boiler arrives in the cylinder 6 by the opening f between the two
pistons c. These are fixed on the same rod, and far enough apart to leave the
orifice completely open. The breadth of the rings or packing segments of
these pistons are equal to that of the ports d, which they cover with sufficient
lap. The movement is imparted to the piston valve by means of eccentrics, in
the same manner as to the ordinary slide valve. But the eccentrics are keyed
in an inverse direction by reason of the admission of the steam from between
pistons c, c, to the ports d (in the direction of the arrows h) and the escape
on the exterior in the direction of the arrows i. It is easily seen that this
piston suffers no friction due from the pressure of steam, and that its working
is facilitated by the escape steam. It will be understood that this piston valve
or valves can be substituted for ordinary slide valve, or any other valve of this
kind. Although the cylinder b should remain open at both ends, the opening
or steam passage f will still be closed between the two pistons.
Distributing piston valves applied as regulators (Fig. 5).-a, steam chest
communicating with the cylinder by means of pipe h; b, cylinder of distri
buting piston valve. This cylinder is open on both ends, and midway there is
an opening f. c, double steam distributing piston valves replacing the slide
valve of the regulator; d, orifices putting the steam chamber of the boiler in
communication with the box a; f, opening in the cylinder 6, to allow the
steam to enter between the two pistons c, c; g, steam chest communicating
with the boiler; h, tube conducting the steam from the chest a to the
cylinders.