IMPROVEMENTS IN THE CONSTRUCTION OF SLIDE VALVES FOR ENGINES WORKED BY STEAM OR OTHER MOTIVE POWER
Year: 1876

page_text: LETTERS PATENT to Alfred Strong, of Finsbury Square, in the County of
Middlesex, for the Invention of "IMPROVEMENTS IN THE CONSTRUCTION OF
SLIDE VALVES FOR ENGINES WORKED BY STEAM OR OTHER MOTIVE POWER."
A communication from abroad by Eugen Schleh, of Cologne, in the German
Empire.
Sealed the 30th September 1876, and dated the 7th April 1876.
PROVISIONAL SPECIFICATION left by the said Alfred Strong at the Oflice
of the Commissioners of Patents on the 7th April 1876.
"IMPROVE-
MENTS IN THE CONSTRUCTION OF SLIDE VALVES FOR ENGINES WORKED BY STEAM
OR OTHER MOTIVE POWER." A communication from abroad by Eugen Schleh, of
Cologne, in the German Empire..
ALFRED STRONG, of Finsbury Square, in the County of Middlesex.
This Invention consists in constructing and arranging cylindrical slive valves as
follows:-
The inventor is aware that the different portions of the valve as constructed by
him are not novel in themselves and have already been used, but he claims as his
Invention an entirely different combination and arrangement of those separate parts,
as also the mode in which they perform their functions when so arranged.
According to the method now in use the steam is made to enter first into the
steam chest, thence through or past the slide valve into the cylinder, whence it
escapes through the exhaust opening in the slide valve into the open air or other-
wise.
According to this Invention the steam is made to pass direct into the slide valve,
thence through the usual ports to the cylinder, whence it exhausts through the
steam chest. The cylindrical slide valve consists mainly of three parts:-
First. The lower or distributing slide or valve.
Second. The upper or inlet slide or valve.
Third. The cylindrical steam chest.
The lower and the upper slides are of cylindrical form, arranged in such a manner
that the lower valve shall move inside the upper one, a tight joint between them
being maintained by means of steel rings. By means ofan adjustable spiral spring
I Price Gd

page_text: the upper and lower slide valves are kept asunder, and at the time pressed against
the inner surface of the cylindrical steam chest, in addition to which the areas of
the ports or passages are so arranged that the steam itself, exercises a certain pres-
sure against the valves, which pressure also tends to keep the valves pressed against
the inner surface of the steam chest.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alfred Strong in the Great Seal Patent Office on the 7th October
1870.
ALFRED STRONG, of Finsbury Square, in the County of Middlesex. "IMPROVE-
MENTS IN THE CONSTRUCTION OF SLIDE VALVES FOR ENGINES WORKED BY STEAM
OR OTHER MOTIVE POWER." A communication from abroad by Eugen Schleh, of
Cologne, in the German Empire.
This Invention relates to improvements in the construction of cylindrical slide
valves.
This Invention can be adapted to all machines whether the motive power be
steam, water, gas, or any other, but it is more particularly applicable to large steam
engines where steam of a high pressure is used, as for instance in locomotive
engines.
According to the method now in use the steam is made to enter first into the
steam chest, thence through or past the slide valve into the cylinder, whence
it escapes through a hollow or opening in the slide valve into the open air or
otherwise.
According to this Invention the steam is made to pass first into the interior or
hollow part of the slide valve, thence through the usual ports or passages into the
cylinder, whence it exhausts through the steam chest, passing on either side and all'
round the slide valve. The advantages of this arrangement are considerable.
In the first place the waste spaces which always exist in the steam chest and
cause condensation and consequent loss of pressure of steam are almost entirely
done away with.
In the second place as there is only the pressure of the waste of exhausted steam
in the steam chest the joints of covers and the stuffing boxes can be more easily
maintained.
A further advantage will be found in the fact that the slide valve itself can be
made smaller, as only one passage for the new steam is required and no exhaust
passage at all.
Again, the steam chest being cylindrical allows.of its being turned on the inside,
which cannot be done with any other balanced slide valve, where generally two or
four perfectly parallel faces have to be produced, a matter of great practical
difficulty and one which no doubt stands in the way of a more general employment
of such balanced slide valves.
What I have said of the valve or steam chests applies with equal force to the
valves themselves.
The arrangement shown in the Drawings of my balanced slide valve, and more
particularly described below, consists mainly of three parts:-
First. The lower or distributing slide or valve.
Second. The upper or inlet slide or valve.
Third. The cylindrical steam or valve chest.
Figure 1 of the accompanying Drawings is a longitudinal section of the valve
chest and valve.
Figure 2 is a cross section of the same.
Figures 3, 4, 5, and 6 are detached views of the lower portion of the valve, while
Figures 7, 8, 9, and 10 are detached views of the upper or inlet portion of
valve.

page_text: Figures 11, 12, and 13 are views of a steam cylinder, to which my improved valve
is shewn applied.
The lower and upper slides are cylindrical in form, their turning faces being at
right angles with their longitudinal axis, they are so arranged that the lower valve
moves inside or within the upper valve, and the escape of steam between the two
valves is prevented by means of steel rings. By the use of an adjustable spiral
spring the two valves are kept asunder and at the same time pressed against the
upper and lower part of the steam chest respectively, in addition to which by an
arrangement of areas of the ports or passages the steam itself is made to exercise
a certain pressure upon the valves, and keeps them tight against the surface upon
which they turn.
A is the lower or distributing slide; B is the upper or inlet slide; C is the
cylindrical steam or valve chest; D, D, D, are steel rings, commonly known as
Ramsbotton's, which are placed in the cylindrical part E of the lower slide A in
order to maintain a tight joint between the slides A and B; F, F, F, is the spiral
spring above described, it is adjustable by means of a set screw G and a pierced
disc H (Figures 1 and 6), and is only intended to act when there is no pressure
of steam within the slide, an escape of steam through non-adhesion to the cylindrical
faces is thereby prevented when steam is again admitted.
The set screw G (Figures 1 and 10) has small notches cut into the head, into
which a small spring I fits and thereby prevents a voluntary turning of the set
screw after it has been set, two larger notches in the head of the set screw serve
to turn the latter by means of a suitably constructed key or spanner.
The cylindrical slide or valve is worked by means of a lever K, which again is
moved by means of an eccentric or any other well-known appliance. The cylindrical
slide valve is kept in its position by means of two nuts and a bar placed upon two
sinal columns on the outside of the steam chest, as shewn in Figure 2.
Having thus described the nature of this Invention, and the manner of practically
carrying out the same, I would have it understood that I do not claim as this
Invention any one of the different portions of which this cylindrical valve consists,
but I claim as the Invention-
First. The use of a cylindrical steam chest with ports as set forth, in combination
with a cylindrical slide vaive operating therein, substantially as set forth.
Second. The use of a balanced hollow cylindrical slide valve, consisting of an outer
part and an inner part, the latter working steam tight in the former, and the two
parts being kept asunder and pressed against the valve seats or hollow steam chest
by the steam and by a spring or springs, all constructed and operating substantially
as set forth.
In witness whereof, I, the said Alfred Strong, have hereunto set my hand and
seal, this Fourteenth day of August, in the year of our Lord One thousand
eight hundred and seventy-six.
ALFRED STRONG. (L.S.)