PROVEMENTS IN APPARATUS FOR OPERATING THE SLIDE VALVES OF STEAM AND OTHER ENGINES
Year: 1878

page_text: "IM-
LETTERS PATENT to Thomas Lumley, of Edgbaston, and Thomas Kavanagh,
of Birmingham, both in the County of Warwick, for the Invention of
PROVEMENTS IN APPARATUS FOR OPERATING THE SLIDE VALVES OF STEAM
AND OTHER ENGINES."
Sealed the 29th April 1879, and dated the 1st November 1878.
PROVISIONAL SPECIFICATION left by the said Thomas Lumley and Thomas
Kavanagh at the Office of the Commissioners of Patents on the 1st November
1878.
THOMAS LUMLEY, of Edgbaston, and THOMAS KAVANAGH, of Birmingham, both
in the County of Warwick. "IMPROVEMENTS IN APPARATUS FOR OPERATING THE
SLIDE VALVES OF STEAM AND OTHER ENGINES."
Our Invention relates to improvements in apparatus for actuating the slide valves
of steam and other engines, and especially those termed direct-acting steam pumps,
steam hammers, steam rivetting machines, blowing engines, exhausters, air com-
pressors, steam caulking machines, rock drills, and the like. The said Invention is
equally applicable to engines driven by steam, compressed air, or water, although,
for the sake of convenience in the following statement, we confine our description to
its use in steam engines.
Our Invention consists in the construction and arrangement of parts herein-after
described to be used in place of tappets, springs, levers, and similar mechanisın
ordinarily used for operating the slide valves of steam engines, steam pumps, and
the like.
According to our said Invention, we fix at each end of the steam or main
cylinder a sliding ring formed like an ordinary piston ring, and which is arranged
to cover a small opening in the said cylinder, and communicating with a chamber
in which is fitted a small piston connected with the slide valve to be operated.
The said rings are so arranged that the piston of the said main cylinder comes in
contact with each of them alternately at the end of its stroke in either direction.

page_text: When the sliding ring at one end of the cylinder is thus acted on, it is moved from
its position over the small aperture which has been covered thereby. The said
aperture being thus uncovered, the steam is exhausted from the chamber at the
corresponding end of the slide valve piston; the slide valve is thereby caused to so
move.or change its position that the steam which last entered the main cylinder
and actuated the piston thereof in one direction is exhausted, and the said piston is
moved in the other direction, or to the other end of the steam cylinder, when a like
movement of the other ring is effected, and the position of the slide valve is again
changed, and so on throughout the working of the engine. We provide for the
admission-of-steam-to-the-spaces-behind-each-end-of-the-valve-piston-by-drilling
small holes through the ends or heads of the said piston.
To ensure the return of the aforesaid sliding rings to cover the small openings
after each of the said rings has been actuated by the piston, we place at the back of
each of the said sliding rings a conical ring which is split and inserted into the
cylinder cover. After each movement or change of position of the slide valve as
above described, the conical ring pressing against the sliding ring that has been
acted on by the main piston, forces it back over the small opening to be again
acted upon by the said piston at the proper time.
To prevent the striking of the cylinder covers or ends by the main piston, we
form a chamber in each cylinder cover to receive a projection provided on either
side of the main piston, which projection serves as a steam cushion.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas Lumley and Thomas Kavanagh in the Great Seal Patent
Office on the 30th April 1879.
THOMAS LUMLEY, of Edgbaston, and THOMAS KAVANAGH, of Birmingham, both
in the County of Warwick." "IMPROVEMENTS IN APPARATUS FOR OPERATING THE
SLIDE VALVES OF STEAM AND OTHER ENGINES."
Our Invention relates to improvements in apparatus for actuating the slide valves
of steam and other engines, and especially those pumping engines termed direct-
acting steam pumps, and of steam hammers, steam rivetting machines, blowing
engines, exhausters, air compressors, steam caulking inachines, rock drills, and the
like. The said Invention is equally applicable to engines driven by steam, com-
pressed air, or water, although for the sake of convenience in the following
statement we confine our description to its use in steam engines.
Our Invention consists in the construction and arrangement of parts herein-after
described and designed to be used in place of tappets, springs, levers, and similar
mechanism ordinarily used for operating the slide valves of steam engines, steam
pumps, and the like.
According to our said Invention, we fix at each end of the steam or main cylinder
a sliding ring formed like an ordinary piston ring, and which is arranged to cover a
small aperture in the said cylinder, communicating with a chamber in which is
fitted a small piston or a pair of such pistons connected with the slide valve to be
operated.
In the accompanying Drawing we have illustrated the application of our Inven-
tion to a steam pump.
Figure 1 is a longitudinal central section through the cylinder and slide valve
casing.
Figure 2 is a transverse section of the same.
Like letters indicate the same parts in both of these Figures. a is the main
cylinder; b, the main piston; c, c¹, are the said sliding rings; d, d¹, are the small
apertures; e, e¹, are conical rings herein-after described; f is the valve casing; g is
the slide valve; h, k, are the aforesaid small pistons; i, i, are chambers in which
the said small pistons work; j,j, are ports or passages extending from the spaces
behind the said pistons to the apertures d, d¹.
The said rings c, c¹, are so arranged that the piston 6 of the main cylinder a comes
in contact with each of them alternately at the end of its stroke in either direction.
When the sliding ring c at one end of the cylinder is thus acted on, it is moved
from its position over the small aperture d which has been covered thereby; the
said aperture being thus uncovered, the steam is exhausted from the chamber i at
the corresponding end of the slide valve casing; the slide valve g is thereby caused
to so move or change its position that the steam which last entered the main
cylinder a and actuated the piston 6 thereof in one direction is exhausted, and the
said piston b is moved in the other direction, or to the other end of the steam
cylinder, when a like movement of the other ring c¹ is effected, and the position of
the slide valve g is again changed or reversed, and so on throughout the working of
the engine. We provide for the admission of steam to the spaces behind each end
of the valve piston by drilling small holes h*, *, through the ends or heads of the
said piston.
The conical rings e, e', are provided to ensure the return of the aforesaid sliding
rings to cover the small apertures d, d', after the sliding ring cor c has been
actuated by the piston b; we place one of these conical rings at the back of each of
the said sliding rings as shown in Figure 1; the said conical rings are split, and
when inserted and forced into the recesses k in the cylinder cover, the said recesses
being smaller than the ring, will cause the latter to close against their elasticity
which tends to open the rings and force them out of the recess. After each move-

page_text: ment or change of position of the slide valve g as above described, the conical ring
pressing against the sliding ring that has been acted on by the main piston forces
the said sliding ring back over the small aperture, to be again acted upon by the
said piston. We may, if desired, use other devices for causing the said rings c, c¹,
to-move-back_over_the_apertures_d, d, such for instance as spiral springs or series of
small spiral springs, or we may use a ring with a small steam passage extending
-from-the-slide-valve-casing to-the-back-of-the said ring..., are the ordinary steam.
ports, and ',, are auxiliary ports or passages which admit steam to the spaces
behind the piston b. It will be seen that the portions of the cylinder occupied
by the aforesaid rings c, c, are of larger diameter than the other portion-of-the-said
cylinder, and form shoulders at a*, which serve as stops for the said rings.
m is a lever which is arranged to engage with the slide valve g, and whose shaft
or spindle m¹ extends through a stuffing box, and is provided with a handle n
outside the casing f. This handle permits the said valve to be conveniently moved
or reversed by band.
The above described apparatus is shewn in the Drawing in connection with a
steam engine, but it will be understood that only very slight if any alterations are
necessary to adapt it to an engine worked by air, gas, or water.
-
Having thus fully described our said Invention, and shown how the same may
be conveniently and advantageously carried into practice, we wish it understood
that we do not claim broadly or as a new principle or method of actuating the slide
valve of a steam or other engine the working of such valves without the intervention
of excentrics, cams, levers, or other mechanical devices, or parts of the engine by
means of a piston or pistons moved to and fro in the valve chest or casing by the
pressure of the steam or other fluid, but we claim,
The improved apparatus consisting of a sliding ring in one or both ends of the
main cylinder in combination with the piston therein, which ring capable of
moving to and fro to cover and uncover an aperture communicating with a space
behind a small piston or pistons connected with the slide valve, and is moved to
uncover the said aperture by the main piston, and is arranged in combination with
a conical ring or with other suitable devices to cause it to return and cover the said
aperture after each stroke of the main piston, as above set forth and for the purpose
specified.
In witness whereof, we, the said Thomas Lumley and Thomas Kavanagh,
have hereunto set our hands and seals, this Twenty-sixth day of April, in
the year of our Lord One thousand eight hundred and seventy-nine.