IMPROVEMENTS IN THE SLIDE VALVES OF STEAM ENGINES
Year: 1867

page_text: LETTERS PATENT to Justin Thévenet, of Mont sur Marchienne lez
Charleroy, in the Kingdom of Belgium, Civil Engineer, for the Invention
of "IMPROVEMENTS IN THE SLIDE VALVES OF STEAM ENGINES"
COMPLETE SPECIFICATION filed by the said Justin Thévenet at the
Office of the Commissioners of Patents, with his Petition and Decla-
ration, on the 4th May 1867, pursuant to the 9th Section of the
· Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JUSTIN
THÉVENET, of Mont sur Marchienne lez Charleroy, in the Kingdom of Bel-
gium, Civil Engineer, send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS IN THE
SLIDE VALVES OF STEAM ENGINES," and have petitioned Her Majesty to grant
unto me, my executors, administrators, and assigns, Her Royal Letters Patent
for the same, and have made solemn Declaration that I verily believe myself
'to be the first and true Inventor thereof.
NOW KNOW YE, that I, the said Justin Thévenet, do hereby declare
that the following Complete Specification under my hand and seal fully
describes and ascertains the nature of my said Invention, and the manner in
which the same is to be performed, reference being had to the Drawing bereto
annexed, and forming part of this Specification, and to the figures and letters
marked thereon:-

page_text: My Invention relates to improvements on my Invention for which Letters
Patent were applied by me on the Thirteenth day of March, One thousand
eight hundred and sixty-seven, No. 718, under the title of improvements in
the slide valves of steam engines, and consists chiefly in constructing slide
valves with a definite pressure, first, with a double friction plate independent
of the box, secondly, with a double friction plate independent of the box and
moveable.
And to make my Invention better understood I will proceed to describe the
same by the aid of the accompanying Drawing.
DESCRIPTION OF THE DRAWING.
Figure 1 shews two slide valves each consisting of two parts, A and B,
A and B', independant of each other, and sliding one on the other without
loss of steam by means of a metallic hoop E and E', or at will by means of
several metallic hoops; each of the parts A, B, A' and B¹, receives from the
steam circulating in the valve box a given pressure to obtain, first, the contact
of the parts A and A' with the friction plates X and X', and, secondly, the
contact of the parts B and B with the supplementary friction plate Y, which
in this case is common to the two slide valves; this plate Y which is inde-
pendent of the box is kept in any suitable manner in the direction of the play
of the valves, but two of its faces should always be respectively exactly parallel
to each of the properly so called two friction plates X and X'. Each of the
slide valves is represented as being worked by means of frames C and C¹.
Spring blades R and R' placed between the parts A and B, A and B, of
each valve insure by an initial pressure the contact of the two parts of the
valves with their respective friction plates in case the steam in the box is at a
very low pressure.
Figure 2 is a view in plan of Figure 1; Figure 3 is a transverse section of
Figure 1; Figure 4 shews a slide valve in two parts A and B sliding one on
the other and working as a piston in a hollowed frame C;, for each of these
parts two. metallic hoops E and D do the work of piston boops and intercept
communication between the inlet steam and that of the outlet steam. The
two parts A and B each receive a given pressure which insures their contact,
first, with the ordinary friction plate ✗ of the valves,, secondly, with the sup-
"plementary friction plate Y; in this case the independent friction plate Y is
kept in any suitable manner in the direction of the play of the slide valve, but
its face of contact with the part B should always be exactly parallel to the
ordinary friction plate X of the slide valves. The initial pressure insuring
the contact of the parts A and B with the friction plates in the case of a

page_text: low pressure of steam in the valve box will be supplied by means of spring.
blades acting between the two parts A and B.
Figure 5, view in plan of Figure 4; Figure 6, transverse section of
Figure 4.
Figure 7 shews the slide valve in two parts constructed on the same prin-
ciple as the slide valves in Figure 1. The friction plate Y is provided with
an opening in communication with the exterior of the box, and which can
serve either for the escape of steam or for the introduction of steam from
the boiler. In the case of Figure 7 the opening is supposed to be made in
the plate Y to serve for the escape of steam. The initial pressure for the
contact of the two parts of the valve is given by the spiral springs R acting
between these two parts, Figure 8; if it is desired; on the contrary, that the
opening above described should serve for the introduction of steam it would
be necessary to alter the distances between the openings of the plate X, to
place the exterior covers of the slide valves at their interior, and reciprocally
the interior covers of the valves at their exterior, in which case the metallic
hoops which intercept the communication of steam between its escape and
its introduction should be placed in the interior of the valve of which the
two parts A and B would then slide in a métallic sheath F, as shewn in
Figure 8.
Figure 9 represents one of the instances where the supplementary friction
plate Y independent of the box is moveable. In this case the valve is of a
single piece A, and the given pressure which insures. its contact, first, with the
ordinary friction plate X of the valves, and, secondly, with the friction plate Y,
independent of the box and moveable, is furnished by the friction plate:Y,
which itself only forms one piece, or is connected by any suitable.means to
another piece which cau slide in any suitable stuffing box, the dimensions of
which are calculated so that there shall be no pressure on the plate Y. but
that determined upon; the plate Y can be made moveable in all directions
by means of a knee piece. The contact is formed by the spring blades R
having their points of support on the interior sides of the box and pressing on
the plate Y. or on the piece with which it forms part.
Figure 10 shews an arrangement which is also on the principle of Figure 9,
the part which forms a whole with the friction plate Y, independent of the
box and moveable, works like pistons in a cylindrical part of one, of the sides
of the box; the diameter of this cylindrical part is calculated so that there
shall be no definite pressure on the plate Y.
Figure 11 shews an arrangement similar in principle to that of. Figures 9
and 10. The slide valve is of a single piece and works between the two

page_text: friction plates, one X the ordinary friction plate of the valves, the other Y the
supplementary friction plate moveable independent of the box and receiving a
given pressure; but in this case the plate Y is provided with an orifice in
communication with the exterior of the box, and which serves either for the
introduction or for the escape of the steam, according to the arrangement of
the openings in the plate X and the object which is proposed in arranging the
covers of the slide valve. The arrangement represented in Figure 11 shews
the orifice in question as serving. for the escape of the steam. Figure 12 is a
transverse section of Figure 11.
Figure 13 shews an arrangement of two slide valves each of a single piece
working in the same steam box. In this case the two supplementary and
moveable, friction plates Y and Y₁ fit into one another, but in such manner
that their sliding one on the other should be effected without any passage of
steam, which is obtained by the employment of a metallic hoop D, or at will
by the employment of several metallic hoops. Each of the plates Y and Y¹
receives from the steam contained in the box a previous determined pressure
which will insure the contact of each of the valves respectively with each of
the ordinary friction plates of the valves X and X'. The initial pressure is
furnished by means of spring blades R inserted between the two supplementary
independent and moveable friction plates Y and Y. The union of the two
plates will be secured in any suitable manner between the two valves, in such-
wise however that each of the plates Y and Y¹ shall be respectively parallel
to the friction plate which is directly opposite to it. Figure 14 is a view in
plan of Figure 13.
Having now described the nature of my Invention, and in what manner the
same is to be performed, I wish it to be understood that I do not confine
myself to the precise details herein laid down; but what I claim as new and
desire to be protected is the improvements above described and represented in
the annexed Drawing, and especially,―
Firstly, the employment of a second friction plate independent of the slide
valve box receiving pressure from one of the parts of a slide valve in two parts
at a given pressure, and which will permit of the application of similar slide
valves in all cases, as herein-before described and represented in Figures 1, 2,
3, 4, 5, 6, 7, and 8 of the annexed Drawing.
Secondly, the employment of a second friction plate independent of the box
and moveable only in.the.direction of the pressure desired to be given to the
slide valve, which may be of one piece, as herein-before described and repre-
sented in Figures 9, 10, 11, 12, 18, and 14 of the Drawing.
Thirdly, the employment of a second friction plate independent of the box

page_text: and moveable in all directions by means of a double joint or knee piece
adjusted between it and the stuffing box or piston, which it equilibrates so
that the slide valve at a given pressure, and which may be of one piece, may
always work well even between two friction plates non-parallel, as herein-
before described and shewn in Figures 9 and 10 of the, Drawing.
Fourthly, the placing a single friction plate between the two slide valves,
Figure 1, or two plates joined together and susceptible of moving slightly
apart without loss of steam, as herein-before described and represented in
Figure 18 of the Drawing.
Fifthly, the means of securing the initial contact between the valve or
valves with their friction plates by means of springs, as herein-before described
and represented in Figures 1, 3, 4, 6, 7, 9, 10, 11, and 13 of the Drawing.
Sixthly, the means for avoiding the steam escape in the cylinder, as herein-
before described and shewn in Figures 7, 8, and 11 of the Drawing.
Seventhly, the means of introducing steam through an exterior pipe, and of
causing its escape through the box in which the slide valve slides, as herein-
before described and represented in Figure 8 of the Drawing.
In witness whereof, I, the said Justin Thévenet, have hereunto set my
hand and seal, this First day of May, One thousand eight hundred and
sixty-seven.