Improvements in Slide Valves and Slide Gear for Steam Engines.
Year: 1889

page_text: Date of Application. 14th Aug., 1889
Complete Specification Left, 14th May, 1890-Accepted, 28th June, 1890
PROVISIONAL SPECIFICATION.
Improvements in Slide Valves and Slide Gear for Steam Engines.
We DRUITT HALPIN of No. 9 Victoria Chambers Victoria Street, Westminster
London S.W. Civil Engineer and ILLUIS AUGUSTUS TIMMIS of No. 2 Great George
Street, Westminster London S.W. Civil Engineer, do hereby declare the nature of
this invention to be as follows:-
In the specification of Letters Patent granted to Druitt Halpin on the 3rd Sept.
1878 No. 3495 ho described a slide valve which while it is moved longitudinally to
and fro by a rod worked from an excentric in the usual way is also caused to rock in
a plane parallel to the slide face by the action of another rod worked by expansion
goar, the face of the slide and the cylinder ports being so shaped that by the rocking
movement of the slide combined with its longitudinal reciprocation the cut off can be
varied while the exhaust remains constant and in specification of Letters Patent
granted to Druitt Halpin on the 6th April 1882 No 1675, he describes a further
improvement in the construction and arrangement of slide valves, and the gear for work-
ing them, whereby he was enabled to obtain the same results in a more simple manner
dispensing with one of the slide rods and its necessary packing. Our present inven-
tion relates to a still further improvement in this class of valves and we obtain the
advantage of keeping the lead and exhaust constant while varying the expansion by
imparting two distinct motions to the one slide valve, a motion of uniform range
which controls the exhaust and a variable motion which controls the entrance and cut
off of the steam in the working cylinder it being clearly understood that both these
motions are perfectly independent. For this purpose we employ a valve or valves of
the Corliss type having an exhaust cavity of the nature of the exhaust cavity in
ordinary slide valves the exhaust steam being emitted through this exhaust cavity.
The motion to produce this exhaust being derived from an oscillating motion of the
valve actuated by an excentric or a crank in the usual manner. On the outside of the
valve in the part usually known as the lap we place one or more openings which are
for the admission of working steam into the cylinder. The steam ports in the cylinder
terminating in suitably shaped openings to suit the openings in the lap of the valve
described above. We impart a longitudinal motion to the valve for the admission of
the steam this longitudinal motion being at right angles to the before described
oscillating motion controlling the exhaust.
This longitudinal motion for controlling the admission of the steam may be either
of a fixed nature or a variable amount or a motion of the releasing type by which the
valve is suddenly closed at any desired part of the stroke.
In some cases we place a valve of the before mentioned description at each end of
the cylinder and in other cases we employ only one valve to effect the admission and
exhaust of steam from both ends and from both sides of the piston. Where we employ
only one valve we sometimes effect the entrance of the steam by the longitudinal
motion in one direction for supplying steam to one end of the cylinder and by the
longitudinal motion in the other direction for supplying steam for the other end of
the cylinder. In some cases where we consider it desirable, we use a valve or
valves of the above described type made so as to be completely or partially balanced.
Dated this 14th day of August 1889.

page_text: COMPLETE SPECIFICATION.
Improvements in Slide Valves and Slide Gear for Steam Engines.
We DRUITT HALPIN of No. 9 Victoria Chambers Westminster London S.W. Civil
Engineer and ILLUIS AUGUSTUS TIMMIS of No. 2 Great George Street Westminster
London S.W. Civil Engineer, do hereby declare the nature of this invention and
in what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement :-
In the specification of Letters Patent granted to Druitt Halpin on the 3rd Sept.
1878 No. 3495 he described a slide valve which while it is moved longitudinally to
and fro by a red worked from an excentric in the usual way is also caused to rock in
a plane parallel to the slide face by the action of another rod worked by expansion
gear, the face of the slide and the cylinder ports being so shaped that by the rocking
movement of the slide combined with its longitudinal reciprocation the cut off can be
varied while the exhaust remains constant and in the specification of Letters Patent
granted to Druitt Halpin on the 6th April 1882 1675 he describes a further improve-
iment in the construction and arrangement of slide valves and the gear for working
them, whereby he was enabled to obtain the same results in a more simple manner
dispensing with one of the slide rods and its necessary packing Our present inven-
tion relates to a still further improvement in this class of valves and we obtain the
advantage of keeping the lead and exhaust constant while varying the expansion by
imparting two distinct motions to the one slide valve a motion of uniform range which
controls the exhaust and a variable motion which controls the entrance and cut off of
the steam in the working cylinder it being clearly understood that both these motions
are perfectly independent. For this purpose we employ a valve or valves of the
Corliss type having an exhaust cavity of the nature of the exhaust cavity in ordinary
slide valves the exhaust steam being emitted through this exhaust cavity. The motion
to produce this exhaust being derived from an oscillating motion of the valve actuated
by an excentric or a crank in the usual manner. On the outside of the valve in the
part usually known as the lap we place one or more openings which are for the
admission of working steam into the cylinder. The steam port in the cylinder ter-
minating in suitably shaped openings to suit the openings in the lap of the valve
described above. We impart a longitudinal motion to the valve for the admission of
the steam this longitudinal motion being at right angles to the before described
oscillating motion controlling the exhaust.
This longitudinal motion for controlling the admission of the steam may be either of
a fixed nature or a variable amount or a motion of the releasing type by which the
valve is suddenly closed at any desired part of the stroke.
In some cases we place a valve of the before mentioned description at each end of
the cylinder and in other cases we employ only one valve to effect the admission and
exhaust of steam from both ends and from both sides of the piston. Where we employ
only one valve we sometimes effect the entrance of the steam by the longitudinal
motion in one direction for supplying steam to one end of the cylinder and by the
longitudinal motion in the other direction for supplying steam for the other end of
the cylinder. In some cases where we consider it desirable we use a valve or valves
of the above described type made so as to be completely or partially balanced.
The drawings herewith together with the following description will make the inven-
tion more readily understood.
Fig. 1 shows an engine in plan having the valve gear arranged according to one
modification of our invention.
Fig. 2 is an end view.
Fig. 3 a side elevation partly in section.
Fig. 4 a cross section partly through the steam cylinder; all these views being of
the same engine.

page_text: Fig. 5 shows in cross section an enlarged view of one form of the valve when the
balancing arrangement is applied;
Fig. 6 is the same valve partly in plan, and partly in section, and
Fig. 7 shows an enlarged section through the lap of the valve showing the steam
entrance passages through the valve; as well as the steam passages into the cylinder.
In all the figures the same letters refer in all cases to the same parts. A A is the
engine frame or bed B B B is the cylinder, C is the valve for regulating the
admission cut off, and exhaust of the steam from the cylinder.
In the drawings now being described there are two such valves, one being placed
underneath each end of the cylinder. In fig. 3D shows the ports for admitting
steam to the cylinder, and for releasing it after it has done its work there, and E in
the same figure shows the port which puts the exhaust port in the valve in communi-
ention with the receiver of the next cylinder if the engine is worked on the compound
system or with the outer air; or with the condensor. An oscillating motion is
imparted to the steam valves by means of the levers marked F which are shown
vertically in Fig. 3 and in plan in Fig. 1, these levers being worked by a fixed
eccentric keyed on to the crank shaft. This motion controls the admission, and
release of the steam.
A longitudinal motion is also imparted to the valves through their valve spindles I I
Figs. 1. 2. 3 and 4 by means of the tripping levers K K actuated by the bell crank
levers L L Fig. 1 to which suitable motion imparted by the expansion eccentric
moved by the crank shaft, whose centre line is shown on Figs. 1 and 2. Suitable
books are provided on one end of each of the tripping levers, which engage with
suitably formed catch pieces on the valve spindles and the valves are moved in a
longitudinal direction so long as they are engaged with the books. In fig. 4, H shows
an enlarged end of the valve spindle its object being always to draw the valve in its
own direction, owing to the unbalanced steam pressure. M M Figs. 1. 2 and 4
show any approved form of air buffer to take up the shock when the valve is released
from the tripping gear. The tripping levers K are provided at the ends opposite to
the engaging hooks with suitably formed toe pieces which at a certain part of the
stroke come into contact with the rollers N N and thus release the valve, the position
of the rollers which are carried on eccentric spindles O Fig. 2 being determined by
the governor to which these spindles are connected by the levers and rods shown in
Fig. 1. Where it is not desired that the engine should be automatically governed the
position of release may of course be determined by hand.
Figs. 5 and 6 show enlarged views of one form of our arrangement for balancing
the valve when desired, the steam inlet being at P the port to the cylinder at Q and
the exhaust passage at R.
The valve is made circular in two parts S and T. These parts being joined together
by an internal sleeve or bush U U and an external packing as at V V being provided
when found necessary. Both oscillating and reciprocating motions are imparted to
the valve by means of valve spindle W which is given the form of a frame where it
passes the valve. Fig. 7 shows a section through the steam ports in the cylinder
marked X and the steam ports in the valve marked Y.
We do not bind ourselves to the particular design as illustrated as the invention
may be equally well carried out when the details are varied.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is
First In Corliss and similar steam engines in which the distribution is effected by
one or by two separate rotary valves a valve gear to secure a constant lead and
exhaust with a variable admission-this being obtained by the imparting to the dis-
tributing valve or valves of two distinct and independent motions, one of uniform

page_text: range controlling the exhaust and produced by a partial rotary motion of the valve
the other a longitudinal axial one produced by a system of bell cranks which are
thrown out of gear at any part of the stroke by cams whose positions are determined
by the governor, this release being assisted by the action of steam on a piston on the
valve spindle substantially as described.
Secondly-The balanced circular valve shown at figs. 6 & 7 substantially as
described.