Steam Valves and Casing for Engine Cylinders.
Year: 1891

page_text: Date of Application, 26th Jan., 1891
Complete Specification Left, 15th Oct., 1891-Accepted, 21st Nov., 1891
PROVISIONAL SPECIFICATION.
Steam Valves and Casing for Engine Cylinders..
I, FRANCIS WILLIAM WEBB, of Chester Place, Crew, in the County of
Chester, Mechanical Engineer, do hereby declare the nature of this invention to
be as follows:
My invention relates to & consists in the application of a casing with piston valves
to engine cylinders which have previously been fitted with the ordinary rectangular
slide valves. The casing, made of cast iron, is of such a length & width as to cover
the entire valve facing of the steam chest & is firmly secured thereto & prevented
from moving endways by lips, which project over each end of the valve facing, or
other suitable means. The casing is divided into three chambers, each of which
has a rectangular outlet leading to the cylinder, corresponding in length
& breadth to the steam & exhaust ports in the face, & with which they are
in direct communication. Steam is admitted to each of these chambers by
means of piston valves, which may be of any convenient size & number to
give the necessary area for the passage of the steam (1) from the steam.
chest to the cylinder & (2) from the cylinder to the exhaust. These several
valves are connected to one common crosshead, which may be within the steam
chest, or outside, as most convenient, & which is coupled to the valve.rod.&
actuated in the same way as when the ordinary slide valve is used.
Secondly. My invention relates to an improvement in piston valves for use in
engine.cylinders. The valves are simple pistons having twisted wings or feathers
projecting from each end & which have a twofold object-(1) The feathers being in
the form of a screw each time the steam comes in contact with them, it has a
tendency to give the valve a slight turn, & thereby prevent grooves from being
formed in the valve or its seat. (2) The wings act as guides for the, valve when at
each end of its stroke.
Tinted this 021 d...
Tanum 1001
COMPLETE SPECIFICATION..
Steam Valves and Casing, for Engine, Cylinders.
I, FRANCIS WILLIAM WEBB, of Chester Place, Crewe, in then County of
Chester, Mechanical 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:-
1
My invention relates to and consists in the application of a casing with piston.
valves to engine cylinders which have previously been fitted with the ordinary...
rectangular slide valves.
The casing, made of cast, iron, is of such a length and width as to cover the
entire valve facing of the steam chest, and is firmly secured thereto and prevented.
from moving endways by lips which project over each end of the valve facing, or
other suitable means. The casing is divided into three chambers, each of which
has a rectangular outlet leading to the cylinder, corresponding in length and
breadth to the steam and exhaust. ports in the face, and with which they are in
direct communication. Steam is admitted to each of these chambers by means of
piston valves, which may be of, any convenient size and number to give the-
necessary area for the passage of the steam (1) from the steam chest to the 'cylinder,
and (2) from the cylinder to the exhaust.

page_text: These several valves are connected to one common crosshead which may be
within the steam chest, or outside, as most convenient, and which is coupled to
the valve rod and actuated in the same way as when the ordinary slide valve is
used.
Secondly. My invention relates to an improvement in piston valves for use in
engine cylinders. The valves are single pistons having twisted wings or feathers
projecting from each end and which have a twofold object-(1) The feathers being
in the form of a screw, each time the steam comes in contact with them, it has a
tendency to give the valve a slight turn, and thereby prevent grooves from being
formed in the valve or its seat. (2) The wings act as guides for the valve when
at each end of its stroke.
Fig. 1 is a longitudinal section through the valve chest and ports of a cylinder
for an ordinary slide valve, and also through the casing applied to the ports and
one set of piston valves fitted to work within the casing.
Fig. 2 is a transverse section through the valve chest and casing for the piston
valves, the section through the casing on one half being through the hole or
cylinder in which the piston valve fits and works and on the other half through
the cavity in the casing that comes opposite the ordinary steam and exhaust ports.
Fig. 3 is a plan section through the valve chest and with respect to one half of
the casing, a section through it, with an outside plan view of one set of piston
valves in position, the other half of the casing in this figure being a top or plan
view thereof.
Fig. 4 is a longitudinal section and elevation of one of the piston valves
detached,
Fig. 5 is a similar view but at a right angle to that shown by Fig. 4, and
Fig. 6 is an end elevation of the piston valve.
The casing a, is placed on the seating of the ordinary slide valve and it is faced
on its underside to fit steam tight to the valve facing and it has descending lips a',
at each end to fit the outside edges of the ordinary slide valve ports in order to
keep it from moving endways, and it is or may be kept down in position by a set
screw b, screwing through the back of the valve chest c.
-
One cavity, in the casing a, comes opposite and communicates with the
ordinary exhaust port, and the other two cavities a³, come opposite to and
communicate with the "steam ports" for the ordinary slide valve.
In the casing a, there are holes bored out for one or more sets of piston valves,
three sets being shown in the drawings.
One set consists of two pistons d, which are connected together on the same rod e,
with a tube e¹, on the rod to keep the pistons at the proper distance apart.
One piston is first put upon the rod e, and comes against a shoulder upon it
(see Fig. 1) then the tube e, and then the other piston which are screwed up
together by a screw nut e², on the end of the rod, which nut is prevented from
unscrewing by a cotter e³, passing through a hole across the end of the rod e.
It will thus be seen that both pistons d, will move endways together, and that they
can be arranged to give the required "lap" over the ports as in the ordinary slide
valves.
The pistons d, move endways with the rod e, and can rotate therewith.
One end of each rod e, for each set or pair of piston valves is connected with a
cross head on the end of a spindle f', corresponding to that for the ordinary slide
valve and this spindle f, is arranged to pass through an ordinary stuffing box so as
to close the valve chest, and the spindle f¹, is actuated in any ordinary and usual
manner by excentric or other valve gear.
It will be seen that there is a shoulder on the spindle e, for each set of piston
valves that comes against the cross head, on one side, and a screw nut, upon.
the end of the spindle comes against the other side of the cross head f, leaving the
spindles e, free to rotate in the holes in the cross head f. This arrangement is used
in order to carry out the second part of my invention for allowing and causing
piston valves to rotate more or less while reciprocating to and fro in order to

page_text: prevent the grooving of the pistons and their cylinders or facings which is liable to
occur when the piston valves are kept in the same position.
In order to cause more or less rotation in the piston valves d, helically formed
wings or projections d', are formed at each end of each piston valve, three are
shown in the drawings but any desired number may be used.
The current of steam passing these helically shaped wings acts upon them and
causes the piston valve to rotate slightly. The edges of these wings d', are turned
to fit the bore of the cylinders a', for the pistons d, and thus guide the ends of the
pistons over the edges of the cylindrical ports.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, I wish it to be understood
that I am aware that piston valves are old and well known, and that it has been
proposed to use two or more of such valves side by side and so as to be actuated
from the same mechanism, and I wish it to be understood that I make no claim to
piston valves so arranged, but what I do claim is-
1. In steam engine cylinders having valve ports designed for the ordinary slide
valve, the application to and combination therewith of a casing in which one or
more sets of piston valves without packing rings are arranged, which piston valves
are actuated by connection with gearing in a manner the same or similar to that
for actuating ordinary slide valves, substantially as hereinbefore described and
illustrated by the drawings.
2. The arrangement of piston valves so as to be rotated in their cylinders or
facings by applying thereto, helical wings substantially as hereinbefore described
and illustrated by the drawings.
3. The combination of helical wings with piston valves substantially as and for
the purpose hereinbefore described.
4. The combination of piston valves having helical wings with a casing secured
over the ports of steam engines arranged for ordinary slide valves, substantially as
and for the purpose hereinbefore described.
5. In steam engines with ports designed for the ordinary slide valve, the com-
bination of a casing with such ports, one or more piston valves, having helical
wings, and with the spindles of the piston valves in a cross head for giving them
end motion in which they can rotate, substantially as and for the purpose herein-
before described.
Dated this Fourteenth day of October 1891.
PETER J. LIVSEY,
Agent.