An Improvement in or applicable to Piston Valves.
Year: 1899

page_text: Date of Application, 15th June, 1899-Accepted, 22nd July, 1899
An Improvement in or applicable to Piston Valves.
I, WILLIAM BUCKLEY, of Patent Piston Works, Millsands, Sheffield, York-
shire, Engineer, do hereby declare the nature of this invention and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement:-
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6
This invention relates to an improvement in or applicable to piston valves of
steam, air and other motive fluid engines, its object being to prevent excessive
compression of the motive fluid (hereinafter referred to as steam") from taking
place in the cylinder wherein the piston works and the consequent risk of break-
ing of the piston valve rings or bursting of the cylinder, which now, at tinies,
occurs when the engine is being reversed and the steam ports are closed after the
cylinder has received a charge of steam by the piston valves being brought into
and allowed to remain in their mid position.
To this end, the invention consists in the application to such piston valves of a
relief valve (or valves) adapted, when the pressure in the cylinder exceeds the
boiler pressure, to open a communication through the piston valve serving to
allow the excess pressure either to escape back into the boiler or steam chamber
or to escape into the exhaust receiver.
In carrying the invention into effect, the piston valve is formed between its
steam and exhaust edges with circumferential openings and with a passage or
way through its block or body connecting such openings with other openings
formed in its end or cover and through which either the steam or the exhaust
or receiver pressure has access, and is adapted or fitted either within its body or
at its end or cover with a relief valve (or valves) normally closing such through-
way and held to its seating by a spring (or springs) and also weighted either by
the steam pressure or by the exhaust pressure in such a manner that, when the
cylinder steam ports are closed by the piston valves and compression occurs in
the cylinder, the pressure in the latter, when exceeding the boiler pressure, will
open the relief valve or valves and allow the surplusage to escape back into
the boiler or steam chamber or to escape into the exhaust receiver, accordingly
as the piston valve is adapted.
In cases wherein the piston valve is fitted with a single broad packing ring,
the latter is also formed with circumferential holes corresponding with the cir-
cumferential openings in the piston valve body.
On the accompanying drawings, which represent various examples or ways
of applying such relief valves to piston valves;
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Figures, 1, represent elevations, partly in section, and Fig. 2, represents a
plan, partly in section of a pair of piston valves each fitted, within its body,
with a relief valve, and show also, in section, the liners of the working barrels
in which the piston valves work, and the ports with the valves in their mid
position;
Fig. 3, represents an elevation, partly in section, and Fig. 4, represents a
plan, partly in section, of a piston valve fitted, within its body, with a double
beat relief valve:

page_text: Figs. 5, and 6, represent like views of a piston valve fitted, at its end or cover,
with a relief valve; and
Figs. 7, and 8, represent like views of a piston valve fitted, within its body,
with a radial relief valve.
Like reference letters indicate like parts wherever repeated on the drawings.
a, (Figs. 1, and 2,) represents the liners of the working barrels within which
the piston valves work and which are formed with steam ports, b; and c, repre-
sents the piston valves each fitted with a broad packing ring or with narrower
packing rings, d, distended by packing springs, e, against the inner wall of the
liner.
The piston valve, in accordance with the present improvement, is formed,
between its steam and exhaust edges, with circumferential openings, f, (as is
also its packing ring, if it consists of a single deep ring, formed with corre-
sponding circumferential holes, g,) and also with openings, h, through its end
.or cover on the steam or on the exhaust side of the valve, and with a passage or
throughway, i, connecting the openings, f, and h, and is fitted with a relief valve
or (valves,) normally closing the through communication and held to its seating
by a spring, k, as well as being weighted either by the steam pressure or by
the exhaust pressure, as aforesaid.
In the arrangement represented in Figs. 1, and 2, the relief valve, j, is a flat
faced circular disc valve located around a central boss, 1, formed on the piston
valve body, m, and on which, when opening, the valve j. is guided in an axial
direction. The valve body, m, extends to the full diameter of the piston valve
and forms a distance piece dividing the two packing rings, d, the adjacent edges
of which rest thereagainst. The two piston valves are joined together by a
waist, n, and are shown as arranged with steam from the boiler filling the space
between the two piston valves, and the openings, h, correspondingly arranged on
the inner ends of the valves and being made of ample area to admit the boiler
pressure freely to the relief valves so that the latter valves can only open when
the pressure on their opposite sides exceeds the boiler pressure.
In the arrangement represented in Figs. 3, and 4, the body of the piston
valve is adapted to receive a double beat relief valve, j, and its end cover has
openings, h, opening into a recessed through way, i, formed on its underside and
into which the relief valve opens, and the arrangement admits of the relief
valve being weighted by the exhaust or receiver pressure as well as by the
spring, k.
In the arrangement represented in Figs. 5, and 6, the openings, h, from the
throughway, i, through the piston valve end cover are closed on the outside by a
flat faced disc relief valve, j, which opens outwardly beyond the end cover. Such
arrangement is applicable either when steam is admitted to the cylinder at the
ends of the piston valves or between the latter, but, in the latter case, the
exhaust or receiver pressure being at the ends of the valves would require to be
aided in weighting the relief valves by more powerful springs, k.
In the arrangement represented in Figs. 7, and 8, the piston valve body is
enclosed by a single deep packing ring, d, formed with circumferential holes, g,
which communicate with the radial openings, f, formed in the piston valve
body and which terminate in three throughways opening into a central cylin-
drical chamber, i, and are covered by radial relief valves, j, held in position by a
helical coil spring ring, k, and weighted either by the steam or by the exhaust
pressure admitted through end openings, h, as in the previous examples.
It should be understood that the relief valves applied to the piston valves
need not necessarily be of the particular forms or applied in the particular
manners represented on the drawings, which are given merely by way of example.
as various other forms and arrangements of relief valves adapted to perform the
stated function may be used in lieu of those described with reference to the
drawings.

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. The application to piston valves of steam, air and other motive fluid engines
of a relief valve or valves adapted when the pressure in the engine cylinder
exceeds the boiler pressure to open a communication through the piston valve
serving to allow the excess pressure either to escape back into the boiler or steam
chamber or to escape into the exhaust receiver, as set forth.
2. The formation of a piston valve between its steam and exhaust edges with
circumferential openings and with a passage or way through its block or body
connecting such openings with other openings formed in its end or cover and
through which either the steam or the exhaust or receiver pressure has access,
and the fitting of the valve either within its body or at its end or cover with a
relief valve or valves normally closing such throughway and held to its seating
by a spring or springs and also weighted either by the steam pressure or by
the exhaust pressure in such a manner that any excess of pressure in the
cylinder over the boiler pressure will open the relief valve or valves and be
enabled to escape or be reduced, as set forth.
3. The arrangement, in combination, of a piston valve and a relief valve, as
herein before described with reference to Figs. 1, and 2, of the drawings.
4. The arrangement, in combination, of a piston valve and a relief valve, as
hereinbefore described with reference to Figs. 3, and 4, of the drawings.
5. The arrangement, in combination, of a piston valve and a relief valve, as
herein before described with reference to Figs. 5, and 6, of the drawings.
6. The arrangement, in combination, of a piston valve and a relief valve, as
herein before described with reference to Figs. 7, and 8, of the drawings.
T +12+1 love of Tum 1000
DAY, DAVIES & HUNT,
Chartered Patent Agents,
321, High Holborn, London, W.C.,
Agents for the Applicant.