Improvements in the Construction and Arrangements of Slide Valves, Valve Chambers, and Valve Gear for Steam Engines.
Year: 1892

page_text: Date of Application, 17th Mar., 1892
Complete Specification Left, 15th Dec., 1892-Accepted, 28th Jan., 1893
PROVISIONAL SPECIFICATION.
Improvements in the Construction and Arrangements of Slide
Valves, Valve Chambers, and Valve Gear for Steam Engines.
I, AUGUSTE MEILHAN of No. 6 Avenue Victor-Hugo, Chaton, Seine-et-Oise,
France, Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention has for its object an improved construction of slide valves, their
chambers and gear for effecting the distribution of steam to the cylinders of steam
engines, wherein separate slide valves are provided for the admission and the
exhaust of the steam. These slide valves, being made in the form of gratings,
offer a large area for the passage of the steam, and consequently do not oppose
appreciable obstruction thereto; they are arranged directly on the ends of the
cylinder, each one being contained in a separate box or chamber. By this means
all dead spaces in the steam passages are practically avoided. The two admission
slide valves are actuated independently and the two exhaust valves have their
motion regulated in combination with a sway beam.
This arrangement of alide valves may be applied to all kinds of engines, whether
vertical or horizontal and whether of large or of small power.
Thus for example in a horizontal engine I arrange the said slide valves and
apparatus for actuating the same as follows.
I fix on each end of the engine cylinder, a cylindrical extension, with closed end
next the cylinder so as to constitute the cover thereof, and with a central passage
through the one extension, forming the stuffing box for the piston rod. The outer
ends of these extensions are closed by covers, and the interior thereof is divided by
partitions into two compartments, in which are situated respectively the admission
and exhaust slide valves, which, as before stated, are of a grating form and work
upon correspondingly formed admission and exhaust ports formed in the closed end
of. the chamber.
The slide valve rods pass laterally through the sides of the chambers and those for
the admission valves carry rollers at their ends that are pressed by springs acting
at. the opposite ends of the rods against cams on one of two way shafts extending
longitudinally of the cylinder, and receiving rotary motion in any suitable
manner from the engine shaft, the cams being made to move the admission
slide valves in the one direction while the said springs move them in the contrary
direction.
The cams for the two admission valves are on one of the before mentioned way
shafts while the cams for the two exhaust valves are on the other way shaft. The
admission cams rotate with the shaft but can be slid longitudinally upon them, and
they are made of some width and with a variable dwell at different points of their
width. They are both connected together by rods and to a governor whereby,
according as the load on the engine varies, they are shifted so as to open the valves
to steam for a longer or shorter period of the stroke.
The rods of the exhaust valves are also provided with rollers bearing against
their cams and are connected to the ends of a sway beam pivotted to the sides of
the cylinder, so that when the one exhaust cam presses its rod and valve inwards,
the sway beam causes the other rod and valve to move outwards and thus remain
in,contact.with. its, cam, the two cams being of course in diametrically opposite
positions on their, shaft.
The slide valves are made adjustable. upon their rods by a screw adjustment
and the springs. which press them against their cams are also capable of adjustment

page_text: They are kept against the faces of the ports by springs which press with one end
against the valve while the other ends press against abutments on a frame carried
by the valve rod, such frame being made to surround the slide valve so as to carry
it to and fro with it.
The steam is supplied to the chambers of the admission valves by a branched
pipe on one side of the cylinder, while the exhaust is connected by a branched
pipe on the other side of the cylinder to the chambers of the exhaust slide
valves.
Deted thin 17th of ML 1000
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Construction and Arrangements of Slide
Valves, Valve Chambers, and Valve Gear for Steam Engines.
I, AUGUSTE MEILHAN, of No. 6 Avenue Victor-Hugo, Chaton, Seine-et-Oise,
France, 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 :-
My invention has for its object an improved construction of slide valves, their
chambers and gear for effecting the distribution of steam to the cylinders of steam
engines, wherein separate slide valves are provided for the admission and the exhaust
of the steam. These slide valves, being made in the form of gratings, offer a large
area for the passage of the steam, and consequently do not oppose appreciable
obstruction thereto; they are arranged directly on the ends of the cylinder, each
one being contained in a separate box or chamber. By'this means all dead spaces
in the steam passages are practically avoided.
The two admission slide valves are actuated independently by means of revolving
cams, and the two exhaust valves have their motion regulated by means of other
cams in combination with a sway beam.
This arrangement of slide valves may be applied to all kinds of engines, whether
vertical or horizontal and whether of large or of small power.
By way of example, I have shewn on the accompanying drawings the applica-
tion of my said invention to a horizontal engine.
Fig. 1 shews a transverse section on line M N Fig. 2, which shews a plan on
the line OP, the upper slide valves and the gear actuating the same being
removed.
Fig. 3 shews a plan on line QR, the lower slide valves and the gear working
them being removed.
Fig. 4 is a side view on line S T and Fig. 5 another side view on line V X.
Fig. 6 is a vertical section of a cylinder end taken on line ZV Z' Fig. 1.
The cylinder A is closed at its ends. by two boxes B B¹ in each of which is
placed an admission slide C and an exhaust slide D contained in separate compart-
ments. The slides employed are of the gridiron form with multiple ports; they
are provided with a nut a which receives a screwed valve rod; E F are the rods of
the slides C and D. They are guided in the supports dd' by means of suitable
bearings.
The slides are connected to their rods E F by means of the screw nuts a for
the purpose of adjusting their positions relatively to the slide faces, and thus modify,
according to requirements, the admission and exhaust of the steam to and from the
cylinders, or for regulating the engine when put in action.
On the sides of the nuts a are formed wings oo below which are helical springs
which give the pressure requisite for maintaining the slide against its slide face.
The rods E F are actuated by means of cams G and H, which receive motion from
the shafts K L. The shaft K is placed at right angles to the driving shaft which

page_text: drives it by means of mitre bevil wheels; this shaft K carries the two admission
cams G, one for each end of the cylinder. The cams, which have a profile of
oblique form relatively to the shaft in a longitudinal direction, can be slid longi-
tudinally upon the shaft for the purpose of varying the cut off. Such displacement
of the cams G is effected as follows. Each of the cams G has a circular groove p
in which is engaged a collar i; these collars are connected together by two rods k
which keep them at the required distance apart; one of these rods is guided in the
supports n and receives motion from the governor of the engine or from a regulating
lever which indicates the degree of cut off. Each slide rod E carries at one end a
roller which bears against the corresponding cam G; this rod E is guided on
the one hand in the support d and on the other hand by a sleeve e beyond the
slide C.
The sleeve e (shewn at Fig. 7) is surrounded by a helical spring f which bears
with its one end against the nut a and at the other end against a key p¹ passing
through the sleeve e and controlled by a screw g bearing against it. The cam G,
in rotating, compresses the spring f, so that when the cam recedes from the roller c,
the slide is rapidly pushed back by the spring fin expanding again. Each rod E
carries a ring fixed thereon by a key, which limits the backward motion of the
slide, so as to cause it to resume the exact required position in which it closes the
steam ports of the cylinder.
Each exhaust slide D, actuated by the rod F, receives its motion from a
cam H fixed on the shaft L, which receives its motion from the shaft K
through spur gearing b b¹. The rod F carries a roller c¹, and is guided on the one
hand by the support d' and on the other hand by a sleeve which differs from the
sleeve e of rod E in that it has no spring. The two rods F are connected together
by means of a beam M pivotted on a support "fixed to the cylinder, this beam
receives motion alternately from the one or other of the two rods F F, by means
of the collars m, so that when the one rod F is pushed inwards by its cam й, so as
to cause the corresponding slide to open the exhaust port, the movement thereby
imparted to the beam M causes this to move the other rod F outwards, thereby
bringing the corresponding slide into the position for closing its exhaust ports.
Thus each exhaust slide remains respectively in the closed and the open position
during nearly the whole of the piston's stroke.
The steam is admitted to each chest B B₁ by means of a branched pipe P P
while the exhaust steam is led off through a similar branched pipe P¹ P¹.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
Apparatus for supplying the steam to and discharging the exhaust steam from
steam cylinders, wherein slide chests closing each end of the cylinder, are divided
by a partition into two compartments in one of which is situated a steam admission
slide while in the other is an exhaust slide, such slides being of gridiron form, and
being actuated by cams on rotating shafts in such manner that the cams for the
admission slides are made with oblique acting faces and are adjustable on their
shaft so as to vary the cut off according to the speed of the engine, the slides
receiving their closing motion by spring action, while the exhaust slides are con-
nected together by a sway beam so that as the cam of the one exhaust slide moves
the latter so as to open the exhaust ports, the beam moves the other slide so as to
close its exhaust ports, substantially as described.
Dated this 14th day of December 1892.
ABEL & IMRAY,
Agents for the Applicant.