IMPROVEMENTS IN VALVES FOR STEAM ENGINES.
Year: 1882

page_text: LETTERS PATENT to Alexander Melville Clark, of the firm of A. M. and
W. Clark, of 53, Chancery Lane, in the County of Middlesex, Patent Agents,
for an Invention of IMPROVEMENTS IN VALVES FOR STEAM ENGINES.
A communication from abroad by Walter Scott Phelps, of Wortendyke,
Bergen County, State of New Jersey, United States of America, and William
Hofford, of Windsor, Essex County, Province of Ontario, Dominion of Canada.
COMPLETE SPECIFICATION filed by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 3rd July 1882.
"
ALEXANDER MELVILLE CLARK of the firm of A. M. & W. Clark of 53 Chancery
Lane in the County of Middlesex, Patent Agents. "IMPROVEMENTS IN VALVES
FOR STEAM ENGINES. A communication from abroad by Walter Scott Phelps of
Wortendyke, Bergen County, State of New Jersey, United States of America, and
William Hofford, of Windsor, Essex County, Province of Ontario, Dominion of
Canada.
This Invention consists of a piston valve of novel construction combined with a
cylinder and enclosing case or shell as hereinafter described and claimed, the object
being to furnish a balanced valve reliable in action and of durable construction.
In the accompanying drawing, Figure 1 is a longitudinal section of a steam chest
fitted with the improved valve. Figure 2 is a transverse section on line x-x.
Figure 3 is a detail view.
A represents the side of any engine cylinder formed with steam ports a a and
exhaust port b. B is the steam chest; C is the valve case or shell secured upon
cylinder A over the ports ab and formed with slots cc and d in its underside
registering with the ports of the cylinder. The shell C is formed with a circular
aperture extending from end to end, and internally the shell is formed with annular
transverse.grooves eef that connect with the slots c c and d. D is a hollow cylinder
of a size to fit snugly in the longitudinal aperture of the shell wherein the cylinder
is firmly secured, and of a length to project at the ends of the shell. This

page_text: cylinder D is provided with apertures g of suitable shape opening into the grooves
ef of the shell and placed as closely together as may be, sufficient space being left
between the openings for support of the piston valve E which works in the cylinder.
The piston or valve E is upon the end of a rod or stem t and in its general con-
struction consists of heads h h separated by an annular groove or exhaust steam
way. The heads h are packed to fit the cylinder steam tight so as to prevent
leakage of steam into the exhaust space i, and the reciprocation of the valve,
connects the openings g c and ports a with the openings g d and port 6 first at one
end and then at the other.
In detail the heads are made up of bevelled collars & on the rod formed with
sleeves that receive split compression rings m and packing rings n which are
held between collars k and washers o, a nut at the outer end of rod t retaining the
parts securely. There are two compression rings m and packing rings n in each
bead separated by a follower ring p (Figure 3) which is grooved radially on
the side toward the collar k. Between the inner ring m and sleeve 2 is a space
connecting with the grooves in ring p so as to admit steam behind the compression
ring and the space contains a coiled spring q for retaining the parts concentric. The
outer ring m receives steam behind it directly through holes in washer o and in
the sleeve. The rings m serve to prevent leakage while the piston is passing the
ports. The follower p cuts off the live steam from passing behind the inner
compression ring m so that while the outer ring is expanded by steam under
boiler pressure, the inner ring receives behind it the steam or hot gases at their
pressure in the cylinder. The effect is to relieve the pressure in the cylinder to a
certain extent before the exhaust opens and thus relieve the valve of the excessive
upward pressure at the exhaust end, which in ordinary slide valves often lifts them
from their seat. The space may be enlarged to any extent required for relief of the
pressure. The two collars kk are separated by washers that give the proper
length to the valve and width to groove i. The shell C is made with openings 8
in its upper side extending to the grooves ef through which the position of the
valve can be noted in setting it. These openings are covered by a plate as shown,
when the valve is in use.
Having described the nature of the said Invention for "Improvements in valves
for steam engines" and the manner of performing the same, I declare that what I
claim as new and desire to secure by Letters Patent is.
1st: The grooved follower ring p combined with the compressing rings m and
packing rings n, of the piston valve, substantially as and for the purposes set
forth.
2nd. A piston valve provided with two compression rings m and packing rings n
separated by a follower p, the outer rings m being fitted to receive steam from the
chest and the inner rings from the cylinder, substantially as shown and described.
In witness whereof I the said Alexander Melville Clark have hereunto set
my hand and seal this third day of July A.D. 1882.