Improvements in and connected with Motive Power Engines and Locomotives Worked by Steam or Compressed Air.
Year: 1898

page_text: Date of Application, 20th Sept., 1898-Accepted, 12th Nov., 1898
Improvements in and connected with Motive Power Engines and
Locomotives Worked by Steam or Compressed Air.
I, JOHN SHENTON, of 44, Higginshaw Road, Oldham, in the County of
Lancaster, 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:—
This invention relates to improvements in and connected with that type of
motive power engines and locomotives which are adapted for the flat sliding
form of valve and are specially applicable for the high and intermediate cylin-
ders of multiple expansion engines worked by steam or compressed air, the
object being to provide means whereby the excessive friction or pressure between
the valve face and seating is reduced to a minimum.
And in order that my invention may be more fully understood I have caused
to be appended hereunto three sheets of drawings, marked with letters of refer-
ence indicating like parts in the various figures, Sheets I & II showing my
invention as applied to the high pressure cylinder of a compound vertical steam
engine, and Sheet III to a high and an intermediate pressure cylinder of a
multiple expansion engine, Fig. 1, Sheet I, being a vertical section, Fig. 2 a
sectional plan, Fig. 3 a vertical section at line A-B Fig. 2, and Fig. 4 a side
elevation of Fig. 1.
Fig. 5. Sheet II, is a sectional side elevation of Fig. 1. Fig. 6 a sectional plan
of Fig. 5, and Figs. 5 & 7 sections at lines C-D and E-F of Figs. 5 & 6
respectively, at an enlarged scale.
Fig. 8, Sheet III, a side elevation, and Fig. 9 a plan.
In carrying out my invention and referring to Sheets I & II, a is the high
pressure cylinder of a compound engine, where the valve chests are in a line
with the crank shaft, b the valve, c the valve chest.
In case of engines connected direct to alternators or where a rope wheel is
required between the cranks, both the slide valves may be arranged between
the cylinders.
The steam I conduct through the inlet into the interior of the valve b, then
through the usual ports a³, a¹ into the cylinder a, exhausting it into the valve
chest and through the extended branch or outlet_e.
In order to keep the valve b on its seating a², I construct the valve chest
cover c¹ with a cylinder f for the reception of a trunk piston g the outer end
of which is exposed to steam pressure and the area of which in case of a high
pressure cylinder shall be equivalent to the area of the exposed surface of the
interior of the valve 6 plus the area of one end of the cylinder ports a¹.
DQ71

page_text: The back of the valve 6 I preferably form with an incline upon which is
adapted to bear a roller the ends of which may be reduced in diameter and are
mounted in pedestals secured to the interior of the trunk piston g.
In small sizes of engines I may employ the said roller without reduced ends
to rotate in a pedestal corresponding in length with that of the roller which
may be hollow and partly perforated for lubricating the said pedestal.
In lieu of mounting the said roller in the trunk piston g, it may be, in a
similar way, employed upon the back of the valve b and by reversing the trunk
piston caused to bear against its solid end.
The said inclined valve back b¹ is adapted to force the trunk piston g outwards
during the down stroke of the valve b whilst the pressure on the outer end of
the trunk piston always retains the roller h upon the inclined valve back.
The periphery of the trunk piston g I form with annular grooves g' which
are made narrower than the distance the trunk piston reciprocates, in order to
ensure the whole of the surface of the trunk piston cylinder being touched and
thereby worn equally.
The trunk piston g is prevented from turning in its cylinder by means of two
guide pins screwed into the end of the trunk cylinder cover k and to facilitate
lubrication the trunk cylinder is furnished with a lubricator arranged in
connection with a chamber f¹ formed in the said cylinder and holes f communi-
cating with the periphery of the trunk piston.
When the engine has commenced to move and the exhaust steam in the valve
chest c surrounds the exterior of the valve b, the latter is subjected to 'an addi-
tional pressure less the same amount of pressure on the interior area of the trunk
piston g.
This additional pressure would be of small consequence in engines with
cylinders up to about 14 inches diameters, but above these diameters the pressure
becomes very troublesome.
To remove this pressure I construct an automatic device which reduces the
pressure on the trunk piston g at the same ratio as the exhaust in the valve chest
presses on the valve. For this purpose the valve chest e is formed with a small
branch connected by a pipe to the cylinder m² of a small piston m to which
steam passes from the main steam supply pipe d through pipe d¹ connected there-
with, see Figs. 5 & 6, Sheet II.
In a horizontal line with the branch 1, a port f³ is formed in the trunk
evlinder f. connected to the cylinder t of another small piston n, the rod of which
is connected by means of a double ended levers to a plug valve o employed inside
the casing r, which valve is always open at the start of the engine.
Steam is conveyed from the main steam supply pipe d to the outer end of the
trunk piston g through port f, which is at a right angle to port f³, see Fig. 5,
Sheet II, by means of the branch pipe d', pipe q, valve casing r, branch pipe r¹,
pipe and branch 2, the branch pipe being preferably connected to the
main steam supply pipe at the boiler side of the main starting valve, in order
to ensure the steam reaching the trunk piston g before it enters the valve b thus
avoiding the valve being lifted off its seating.
The valve o, see Figs. 5, 5 & 6, has 3 slots o¹, 02, 03 of various width or size,
so as to allow only a very small area to be opened when necessary.
To the spindle of the plug valve o is secured the double ended lever s one end
of which is secured by a link s¹ to the rod n³ of the small piston n arranged in
the cylinder secured to the side of the trunk piston cylinder f and communi-
cating with the port in the latter which leads to the outer end of the trunk
piston and the other end by an ordinary link and a fulcrum link u, to the
rol m' of the piston m.
The fulcrum link u has a slot u¹ in which is fitted a block u², see more
particularly Figs. 6 & 7, carried by and adapted to turn on a stud a³ rendered
adjustable in a slot formed in a bracket el secured to the plug valve casing r
By the combined action of the pressure passing from the valve chest e through

page_text: branch and pipe to the rod side of piston m and that from the cylinder f by
port f3 to the back of piston n, the plug valve is actuated and only admits steam
through pipe p to act upon the outer end of the trunk piston 9, and by adjusting
the fulcrum stud ³ in the slot r, the action of the plug valve o can be regulated
at will so as to give any desired pressure on the trunk piston g.
Referring to Sheet III, in which case the valve chests are formed at right angles
to the crank shaft, which brings the high and intermediate pressure cylinders
nearer together and allows of free access to the trunk cylinder covers, the exhaust
steam from the high pressure cylinder is conveyed underneath the valve of the
intermediate cylinder by a branch formed on the valve chest C of the high
pressure cylinder and in this case a radial valve gear may be used.
XXX
In order to regulate the pressure of steam to the intermediate trunk piston
relative to the power the engine is required to develope, I employ between the
pipe, which by means of an elbow is connected to the port 4 of the high
pressure trunk cylinder and the pipe 2 connected to the elbow pipe *** leading
to the port f5 of the intermediate pressure trunk cylinder, an automatic reducing
valve, consisting chiefly of a piston 23 employed inside a branch 7, the rod of
which piston is jointed to a lever having an adjustable fulcrum block 1
carried by a forked lever a secured to a short shaft 2 mounted in a bracket
and having at the opposite end a lever y connected by a rod yl and two other
levers z&2 which latter are secured to a vertical shaft 22 mounted in a bracket
secured to the trunk piston cylinder cover and by another rod to the double
ended levers on the plug valve o. The said fulcrum lever near its other end is
jointed to the rod t¹ of an equilibrium valve 2 having two discs. The free end
of the said fulcrum lever is suspended by a tension spring 3 secured to a suitable
stationary part of the engine, say to a projection secured to the cover of the
high pressure trunk piston cylinder k.
It will thus be readily understood that the fulcrum block 75 receives its motion
from the double ended levers of the plug valve o and when moved from the
piston the power of the piston will be increased and overcome that of the
spring and thus close the equilibrium valve t².
To the main supply pipe d is secured at right angle a pipe connection d¹ one
branch of which is connected with the piston cylinder m² and the other to a
pipe leading to the plug valve casing r.
I may remark that in order to meet the requirements of the various designs
of engines, the manner of applying the automatic pressure regulating device may
be altered as may be found necessary without departing from the main feature
of my invention.
Drain pipes may be applied where necessary.
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
1st In and connected with motive power engines and locomotives worked by
steam or compressed air of the type hereinbefore described, the combination with
the valve b, of a trunk piston 7 having a roller adapted to hold the valve b
to its seating and wherein live fluid is conveyed underneath the slide valve and
the pressure of which acting under the latter, is counterbalanced by the pressure
of live fluid conveyed to and acting upon the outer end of and transmitted by
the said trunk piston and its roller h upon the back of the slide valve, all sub-
stantially as and for the purpose set forth.
2nd. In and connected with compound and multiple expansion engines, in
combination with the trunk piston g, specified in the preceding claim, a device
for reducing the steam pressure upon the said trunk piston, consisting of a plug
or other suitable valve o interposed between the steam supply pipe d and trunk
piston cylinder f and operated by two pistons n & m and fulcrum link u connected
therewith, all substantially as set forth.

page_text: 3rd. In and connected with multiple expansion engines, in combination with
the steam pressure reducing device, specified in the preceding claim, an automatic
reducing valve interposed between the pipes & 7 of the trunk cylinders of
the high pressure and intermediate cylinder, all substantially as and for the
purpose set forth.
Dated this 17th day of Santember 1808
F. BOSSHARDT & Co.,
4, Corporation Street, Manchester,
Agents to Applicant.