Improvements in Valve Gear for Steam or other Engines Operated by Expansible Fluid.
Year: 1898

page_text: Date of Application, 13th Oct., 1898
Complete Specification Left, 13th July, 1899-Accepted, 19th Aug., 1899
PROVISIONAL SPECIFICATION.
Improvements in Valve Gear for Steam or other Engines Operated
by Expansible Fluid.
I, DAVID JOY, of 118, Broadhurst Gardens, Hampstead, in the County of
London, Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention has for its object the improvement of valve gear for steam or
other engines operated by expansible fluids (which I will hereinafter refer to
as steam) and relates to what are known as assistant cylinders. According to
my invention, instead of employing the piston itself to act as the valve for
admitting steam both under and above the piston and also for exhausting steam
from both, I employ the piston rod, in conjunction with the gland through which
it passes to form the required parts, and by reducing the rod at the right point,
or by drilling it, or surrounding it with a shell to pass the steam to the top of
the piston, and I exhaust the steam as before, by ports in the sides of the cylinder
over which the piston passes.
Or having admitted steam to one end of the cylinder I may pass a part of it,
before it passes to the exhaust, over to the opposite end of the cylinder by ports
in the sides of the cylinder, or by a bar furnished with ports, and fixed in the
cylinder, and over which the piston slides. This bar may be adjustable.
Dated this 13th day of October 1898.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C.,
Agents.
Improvements in Valve Gear for Steam or other Engines Operated
by Expansible Fluid.
I, DAVID JOY, of 118, Broadhurst Gardens, Hampstead, in the County of
London, 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 relates to steam or other engines operated by expansible fluid
(which I will refer to as steam) wherein the valve gear is provided with what is
known as an assistant cylinder. Such a gear is described in the Specification of
British Letters Patent No. 17168 dated 13th December 1887 the piston in the
assistant cylinder of such gear acting as the valve for both admitting and exhaust-
ing steam both to and from under and above the piston.

page_text: According to my present invention I simplify the arrangement and render
it more compact by employing the piston rod in conjunction with the gland
through which it passes to form the required ports to pass the steam alternately
to the top and bottom of the piston which can be done by reducing the rod at
the right point, or by drilling it, or by surrounding it with a shell. The steam
is exhausted as in the previous arrangement by ports in the sides of the cylinder
over which ports the piston passes. Or having admitted steam to one end of
the cylinder I may pass a part of it, before it passes to the exhaust; over to the
opposite end of the cylinder by ports in the sides of the cylinder or by a bar
or post furnished with ports and fixed in the cylinder and over which bar or
post the piston slides. This bar may be adjustable.
Figures 1 and 2 are vertical sections at right angles to each other of an
assistant cylinder constructed according to my invention and Figure 3 is a hori-
zontal section on the line 3-3 Figure 2. Figure 4 is a vertical section of a
modification and Figure 5 is a similar section illustrating another modification.
Figure 6 shews a further modification in which the piston slides along a rod or
bar furnished with ports.
Referring to Figures 1, 2 and 3 A represents a portion of the valve to be
operated, the rod B of which valve carries a piston C fitted to slide in the assistant
cylinder D which is bolted to the valve box A¹. In the gland or neck E of the
cylinder D through which the rod B passes, is an annular port or passage c into
which steam enters by a passage e¹ which is in connection with the boiler or other
source of supply. The rod B for the greater portion of its length accurately fits
the bore in the gland or neck E but is of less diameter than the said bore at the
end which carries the piston so that when the piston is in its lowest position
in the cylinder 1), the shoulder c formed at the junction of the reduced part b
with the larger part of the rod B will be below the annular port or passage c and
steam will enter the cylinder beneath the piston and force the said piston to the
upper end of the cylinder thereby reversing the valve A.
The rod B may be made of uniform diameter throughout and the portion
required to be of larger diameter be increased by a casing as shewn in Figures 1
and 2. In the wall of the cylinder D are ports or passages d which as the piston
rises in the cylinder become partially uncovered so that a portion of the steam
admitted to the under side of the piston will pass through the said ports or
passages to the upper part of the cylinder above the piston and be compressed
by the rising of the said piston. On opposite sides of the cylinder are exhaust
ports d' connected together by a tube preferably of copper the said ports d
being of sufficiently large area to admit of a rapid exit for the
exhaust steam from below the piston as the piston descends
by the expansion of the steam admitted above the piston by the ports das
herein before described, and so effect the reverse movement of the valve A. In
the modification illustrated by Figure 4 the reduced portion b of the valve
rod B is surrounded by a sleeve or casing B¹, an annular space 6 being provided
between the said sleeve B and the piston rod. The external diameter of the
'
sleeve B corresponds with the diameter of the valve rod and forms a continuation
thereof so as to slide in the gland or neck E of the cylinder D. The end of the
sleeve near the piston C is reduced in diameter so as to admit steam to beneath
the piston by the passage e¹ and annular port or passage e when the said piston
is at the lower end of the cylinder. The annular space communicates with the
cylinder D above the piston C, by passages 62 in the piston, lateral passages 63
being provided in the sleeve B¹, which passages when the piston is at the upper
end of the cylinder coincide with the annular port or passage e in the gland or
neck E of the cylinder so that steam entering the said annular port e by the
passage el will pass through the lateral passages into the annular space and
thence through the passages be in the piston to the cylinder above the piston and
effect the down stroke of the said piston and so reverse the rain valve of the
engine as before described. In the modified arrangement illustrated by Figure 5

page_text: el
the rod B is provided with an axial passage b¹ and transverse passages b³ com-
municating with the inner end of the said axial passage When the piston C
ia at the upper end of the cylinder D the passages coincide with
the annular port e in the neck or gland E so that steam entering the passage
will pass through the passage b2 and axial passage 61 into the cylinder D above
the piston C and force the said piston to the opposite end of the cylinder and
thereby reverse the valve connected to the rod B. Instead of forming ports in
the cylinder for the passage of steam from one side of the piston to the other
side thereof the said ports may be provided in a rod or bar F as shewn in
Figure 6 adjustably fixed in the cylinder. The piston C slides on the said rod
which passes through an opening of corresponding size formed in the said piston.
A portion of the rod or bar F is chamfered or cut away as shewn at d to form
passages or ports through which, part of the steam admitted by the passage e¹ to
beneath the piston can pass to the top of the piston and be compressed by the
rising of the said piston, the said steam then acting by expansion to effect the
return stroke of the piston as in the previously described arrangement the exhaust
steam escaping by the port d.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:
1. In combination with the valve gear of engines operated by expansible
fluid an assistant cylinder having the piston rod and the gland through which it
passes so formed or arranged that they constitute the ports or passages through
which the motive fluid passes to the bottom or top of the cylinder.
2. In combination with the valve gear of engines operated by expansible
fluid an assistant cylinder having ports so arranged that motive fluid after acting
on one side of the piston, passes to the other side of the piston to act thereon
expansively before it passes to the exhaust.
3. The combination with the valve gear of engines operated by expansible,
fluid of a cylinder and piston, means for admitting steam to one side of the
piston, recesses or passages (d) in the inner surface of the cylinder through which
recesses steam admitted to one side of the piston can pass to the opposite side of
the said piston to effect by expansion of the said steam, the return stroke of the
piston substantially as hereinbefore described.
4. The combination with the valve gear of engines operated by expansible
fluid, of a cylinder and piston, a rod connecting the said piston to the valve
to be operated; the said rod having a part of less diameter than the other part;
a gland or neck on the cylinder in which the larger portion of the rod slides,
an annular recess or port in the gland, in communication with the steam supply
and situated so that when the piston is at one end of the cylinder the reduced
portion of the rod will be opposite the said port and allow steam to enter the
cylinder, to force the piston to the opposite end of the cylinder, and recesses or
passages (d) in the inner surface of the cylinder through which steam admitted
to one side of the piston can pass to the opposite side thereof to effect the return
stroke of the piston, substantially as herein before described.
5. The combination with the valve gear of engines operated by expansible
fluid, of a cylinder and piston, a rod connecting the said piston to the valve
to be operated; means for admitting steam to the cylinder at one side of the
piston, to force the piston in one direction in the cylinder; recesses in the
interior surface of the cylinder through which steam can pass from one side of
the piston to the opposite side of the said piston to effect by the expansion of
the steam the return stroke of the said piston; and ports or passages in the wall
of the cylinder for the exit of the exhaust steam substantially as herein before
described.
6. The combination with the valve gear of engines operated by expansible
fluid of a cylinder and piston; means for admitting steam to the cylinder to force

page_text: ;
the piston in one direction; a rod connecting the piston to the valve to be
operated; a neck or gland on the cylinder in which the piston rod slides; an
annular recess or port in the said neck or gland in connection with the steam
supply a portion of reduced diameter on the piston rod; a sleeve or casing
surrounding the reduced portion of the piston rod; an annular space between
the sleeve and the reduced portion of the piston rod; transverse openings in
the sleeve communicating with the said annular space and with the annular
recess or port in the neck or gland on the cylinder when the piston is at one end
of the cylinder; passages in the piston through which steam admitted to annular
space can pass into the cylinder to effect the return stroke of piston and ports or
passages in the wall of the cylinder for the escape of exhaust steam from the
cylinder substantially as herein before described.
7. The combination with the valve gear of engines operated by expansible
fluid, of a cylinder and piston means for admitting steam into the cylinder to force
the piston in one direction a rod connecting the piston to the valve to be operated;
a neck or gland on the cylinder in which the piston rod slides; an annular
recess or port in the gland communicating with the steam supply; an axial or
longitudinal passage in the piston rod, a transverse passage in the piston rod
communicating with the axial passage and so situated that when the piston is at
one end of the cylinder the said transverse passage will coincide with the annular
passage or port in the neck or gland and admit steam to the opposite side of the
piston to effect its return stroke; ports or passages in the wall of the cylinder on
opposite sides thereof, for the escape of exhaust steam and a tube or passage con-
necting the said ports or passages substantially as herein before described.
8. The combination with the valve gear of engines operated by expansive fluid,
of a cylinder and piston, a rod connecting the piston to the valve to be operated,
a fixed rod or bar on the cylinder on which the piston slides, a hole in the piston
corresponding to the diameter of the rod through which hole the rod or bar
passes, chamfers or recesses at one portion of the rod or bar to form ports for the
passage of steam from one side of the piston to the other side thereof, means for
admitting steam to the cylinder, and a port for the escape of exhaust steam from
the cylinder substantially as herein before described.
Dotal 1: 1941. JT.... 1000
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C.,
Agents.