IMPROVEMENTS IN VALVES, AND IN APPARATUS CONNECTED THEREWITH
Year: 1856

page_text: LETTERS PATENT to Robert Wilson, of Patricroft, in the County of
Lancaster, Engineer, for the Invention of "IMPROVEMENTS IN VALVES,
AND IN APPARATUS CONNECTED THEREWITH."
Sealed the 4th November 1856, and dated the 5th September 1856.
PROVISIONAL SPECIFICATION left by the said Robert Wilson at the
Office of the Commissioners of Patents, with his Petition, on the 5th
September 1856.
I, ROBERT WILSON, of Patricroft, in the County of Lancaster, Engineer,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
VALVES AND IN APPARATUS CONNECTED THEREWITH," to be as follows:-
This Invention relates to an improved system or mode of constructing valves,
such, for example, as the slide valves of steam engines, in such a manner that
they may not be subjected to unbalanced pressure at any point of their stroke;
and to an improved system or mode of working the slide valves of steam
engines.
In one modification of slide valve, as constructed according to this Invention,
the valve is reetangular in form, and resembles the simplest kind of slide valve
in use, except that the part corresponding to the cup of the valve is cut com-
pletely through the valve, and the valve is formed with parallel working surfaces
on both back and front. The port face of the cylinder is planed in the usual
way, and the valve works between this valve face and a back plate, which is
supported in or forms part of the valve casing, such plate being either rigid,

page_text: adjustable, or arranged to be kept against the valve by springs. This back
plate is planed like the port face, for the valve to work upon it, and it is
formed with recesses exactly equal in area to the cylinder and exhaust ports,
and situated directly opposite to these ports. With this arrangement, when
either of the ends of the valve is partly across a port on the cylinder face, the
steam has access to the corresponding recess in the back plate, and therefore
acts equally on both sides of the valve. When either of the ends of the valve
is wholly across or covers a port in the cylinder face, the steam has access to
the corresponding recess in the back plate, through a small passage or per-
foration formed in the end of the valve, and the pressure is rendered equal on
both sides of the valve in this case also. The valve is thus at all times. free
from unbalanced pressure, and can consequently be worked with a minimum
of power, so that it is peculiarly suitable for mining, marine, and locomotive
engines, and in all cases where facile control of the engine's movements is of
importance, whilst the arrangement may be beneficially adopted in all valves.
This system of construction may obviously be carried out with valves of
various forms, whether their movements or their working surfaces be rectilinear
or curvilinear, or whether their movements be reciprocatory or rotatory, the
essential feature of the Invention being the causing the valve to work between
the port face and a face or surface having recesses formed upon it equal in
area and directly opposite to the ports. It is also obvious that some of the
ports may be made in one face and some in the other, a recess being made
opposite the port in each case. Thus, for example, the exhaust port of a
steam cylinder may be made in the back plate instead of between the two
cylinder ports, a blind recess only being in such case made between the
latter, or an opening or port may be in both, if required.
Another part of the present Invention consists in imparting to slide valves
in a peculiar manner a motion which may be termed "differential," as com-
pared with the motion imparted by an eccentric as ordinarily applied.
In carrying out this part of the Invention the valve is worked by an
eccentric, but means are employed for diminishing and increasing the effective
length of the eccentric rod, or of any rod transmitting motion from the
eccentric to the valve at different periods of the eccentric's revolution. By
these means movements may be given to the valve, either in advance of the
eccentric, or in the opposite direction to the eccentric's action at the time.
Thus the valve may be made to cut off the steam before it would do so with
the common eccentric action. For example, if the valve is at its furthest point
from the shaft, and is admitting steam at its top port, by shortening the rod
the valve will cut off the steam sooner than the eccentric would do this of itself.

page_text: The valve would then be worked with the short rod as it were, until it
reached its furthest point at the opposite end, so as to admit steam into the
bottom port, when the rod would be lengthened again, and so close this port in
advance of the eccentric's return movement. There are various ways of effecting
this increase and diminution in the effective length of the rod, but according to
one plan it is proposed to make the rod of pieces jointed so as to form an
elbow or toggle joint, so that by acting on this joint transversely the required
effect may be produced.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Robert Wilson in the Great Seal Patent Office on the
5th March 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
WILSON, of Patricroft, in the County of Lancaster, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifth day of September, in the year of our Lord One
thousand eight hundred and fifty-six, in the twentieth year of Her reign, did,
for Herself, Her heirs and successors, give and grant unto me, the said Robert
Wilson, Iler special license, that I, the said Robert Wilson, executors,
administrators, and assigns, or such others as I, the said Robert Wilson, my
executors, administrators, or assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term therein
expressed, should and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands, and Isle
of Man, an Invention for "IMPROVEMENTS IN VALVES, AND IN APPARATUS CON-
NECTED THEREWITH," upon the condition (amongst others) that I, the said
Robert Wilson, by an instrument in writing under my hand and seal, should
particularly describe and ascertain the nature of the said Invention, and in
what manner the same was to be performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar months next and imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Robert Wilson, do hereby declare the
nature of my said Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement,
reference being had to the accompanying Drawings, and to the letters and
figures marked thereon, that is to say:-

page_text: My said Invention relates to an improved system or mode of constructing
valves, such, for example, as the slide valves of steam engines, in such a
manner that they may not be subjected to unbalanced pressure at any point of
their stroke, and to an improved system or mode of working the slide valves of
steam engines.
In one modification of slide valve as constructed according to this Inven-
tion the valve is rectangular in form, and resembles the simplest kind of slide
valve in use, except that the part corresponding to the cup of the valve is cut
completely through the valve, and the valve is formed with parallel working
surfaces on both back and front. The port face of the cylinder is planed in
the usual way, and the valve works between this valve face and a back plate,
which is supported in or forms part of the valve casing, such plate being either
rigid, adjustable, or arranged to be kept against the valve by springs. This
back plate is planed like the port face for the valve to work upon it, and it is
formed with recesses exactly equal in area to the cylinder and exhaust ports,
and situated directly opposite to these ports. With this arrangement, when
either of the ends of the valve is partly across a port on the cylinder face, the
steam has access to the corresponding recess in the back plate, and therefore
acts equally on both sides of the valve. When either of the ends of the valve
is wholly across or covers a port in the cylinder face, the steam has access to
the corresponding recess in the back plate through a small passage or per-
foration formed in the end of the valve, and the pressure is rendered equal on
both sides of the valve in this case also; the valve is thus at all times free
from unbalanced pressure, and can consequently be worked with a minimum
of power, so that it is peculiarly suitable for mining, marine, and locomotive
engines, and in all cases where facile control of the engine's movements is of
importance, whilst the arrangement may be beneficially adopted in all valves.
This system of construction may be obviously carried out with valves of
various forms, whether their movements or their working surfaces be recti-
linear or curvilinear, or whether their movements be reciprocatory or rotatory,
the essential feature of the Invention being the causing the valve to work
between the port face and a face or surface having recesses formed upon it
equal in area and directly opposite to the ports. It is also obvious that some
of the ports may be made in one face and some in the other, a recess being
made opposite to the port in each case. Thus, for example, the exhaust port
of a steam cylinder may be made in the back plate instead of between the two
cylinder ports, a blind recess only being in such case made between the latter,
or an opening or port may be in both, if required.
Another part of the present Invention relates to an improved system of

page_text: regulating the time of the several operations the valve performs, namely, the
ingress or supply of steam, the cutting off said supply, and the opening and
shutting of the exhaust, by which means the steam can be cut off at an early
part of the stroke with all the advantages of a great lap on the steam side of the
valve, and yet the exhaust be regulated so as not to open or shut any sooner
than when an ordinary lap is used and worked with an eccentric. This is accom-
plished by the valve being made in two parts, and one part within the other.
The outside part to regulate the supply and cutting off the steam, and the
inside part the opening and shutting the exhaust (which arrangement can
also be carried out without the back balance plate, although under these
circumstances the valve will be subjected to the full effects of the unbalanced
pressure).
Another part of the present Invention consists in imparting to slide valves
in a peculiar manner a motion which may be termed "differential," as com-
pared with the motion imparted by an eccentric as ordinarily applied.
In carrying out this part of the Iuvention, the valve is worked by an eccen-
tric, but means are employed for diminishing and increasing the effective length
of the eccentric rod, or of any rod transmitting motion from the eccentric to
the valve, at different periods of the eccentric's revolution. By these means
movements may be given to the valve, either in advance of the eccentric or
in the opposite direction to the eccentric's action at the time. Thus the valve
may be made to cut off the steam before it would do so with the common
eccentric action. For example, if the valve is at its farthest point from the
shaft, and is admitting steam at its top port, by shortening the rod the
valve will cut off the steam sooner than the eccentric would do this of itself.
The valve would then be worked with the short rod, as it were, until it
reached its furthest point at the opposite end, so as to admit steam into the
bottom port, when the rod would be lengthened again, and so close this port in
advance of the eccentric's return movement. There are various ways of
effecting this increase and diminution in the effective length of the rod, but
according to one plan it is proposed to make the rod of pieces, jointed so as
to form an elbow or toggle joint, so that by acting on this joint transversely
the required effect may be produced.
The transverse movement may be derived from an eccentric or cam. This
motion is peculiarly applicable to the double valve last described, giving it all
the advantages of both the ordinary steam and exhaust valve with that of a
separate expansion valve; also by which with a variable cam motion the steam
may be cut off at any part of the stroke.
And in order that the said Invention may be properly understood, I shall

page_text: now proceed to describe the several illustrative figures on the explanatory
Sheet of Drawings, which I have appended hereunto for the purpose of shewing
certain forms under which my improvements may be judiciously carried out in
practice.
Figure 1 on my Sheet of Drawings is a longitudinal section of one of my
improved valvular arrangements, shewing the valve chest, slide valve, balance
plate, and steam and exhaust ways, all in section. Figure 2 is a corresponding
transverse section of the same parts; and Figure 3 is a plan of the valve,
with its surrounding frame. There the valve chest A has in it the single open
slide valve B, faced on both sides, to work both against the port face of the
steam cylinder and the under side of the balance plate C, which has in it end
adjusting screws D, with their projecting heads bearing against the internal end
surfaces of the steam chest, so that the longitudinal set of the plate can be
varied as required. The valve is worked by the spindle E, and the steam from
the chest finds its way through the opening in this slide to the steam ways F
leading to the two ends of the cylinder. The corresponding recesses in the
balance plate for these ports are at G, and the recess for the exhaust port I of
the cylinder in the same plate is at J. At K are small transverse openings and
thoroughfares in and through the slide valve, for the purpose of keeping up
the steam communication between the steam ports F and the recesses G in
the balance plate, whilst the faces are over these parts.
Figure 4 is a longitudinal section, and Figure 5, a corresponding cross
section, of a modified form of this valvular arrangement, showing the balance
plate A as being formed out of the door of the steam chest, the under side of
this door being faced for this purpose, and having in it the steam balancing
recesses B and the exhaust balance recess C, as in the previous example.
Figure 6 is a plan of the slide valve, detached, showing its communicating
thoroughfares for the balancing action, the whole being arranged in this
instance for a small engine.
Figure 7 is a longitudinal section of a further modification, wherein the slide
valve is duplex, or in two parts A, B.
Figure 8 is a transverse section of the same, and Figure 9 is a plan of the
slide valve, detached. In this instance, the external portion or open frame A
of the valve is the only part which is worked directly by the spindle C. This
external frame portion performs the duty of inlet and cut-off valve, for the
operating steam as it enters from the boiler, whilst the internal portion B of
the valve, which is surrounded on all four sides by the outer frame portion A,
and is only actuated indirectly by the motion of the outer frame, acts purely as
the exhaust valve. The opening in the outer slide is somewhat longer than

page_text: the length of the internal slide, so that when the outer slide moves from one
end of its stroke it leaves the internal slide B behind it to the extent of this
difference in length, as the internal slide never moves until pushed by one
or other of its ends by the corresponding end of the outer slide. The
result of this arrangement is, that the internal slide is so much longer
in opening the exhaust in either direction, as well as in closing on the opposite
sile, and hence the steam can be cut off sooner without having to open the
exhaust or close the opposite slide too soon, than can be effected with a solid
single piece valve. The effect of this arrangement is in reality the same as if
the lap were regularly increased for cutting off the steam, and diminished for
the exhaust action and ingress of steam at the proper time at each stroke. In
other words, the outer slide A has all the power of cutting off the steam at an
early period, which would arise from having an extent of additional lap equal
to the amount by which A travels before B, and B being left thus much behind.
The exhaust is no sooner opened on one side and shut on the other, than if
the face was no broader than that which the two end faces of A and B make
when together, and this movement obviously gives great advantages with the
most simple means.
Figure 12 is a longitudinal section of my improved valve, with the balance
plate and differential or toggle joint action of the spindle attached thereto;
Figure 13 is a plan of the valve, detached, but shewing the differentially acting
parts of the spindle connections. Figure 14 is a longitudinal section of the
valve, shewing the differential action at another point in its movement, as regards
Figure 12. Both sections A, B, of the valve are actuated by the eccentric move-
ment. The outer slide A is worked by the tubular spindle C connected to the
toggle joint link arrangement D, whilst the inner slide B is actuated by the solid
spindle E passing through the tubular spindle. The link F of the solid spindle
passes to a separate eccentric or other movement, whilst the toggle joint action
D is connected at G with its outer special cam or eccentric movement working
at right angles to the axis of the valve spindle.
Figure 12 represents both parts of the valve as at the extreme end of their
stroke, steam having full ingress at H to the port I, whilst full exhaust is going
on from the port J through the interior K of the valve, the toggle joint being
straight, or with both its links in a line.
In Figure 14 the toggle joint is bent, that is to say, the central joint is
drawn downwards, the outer side A being consequently drawn over the port I,
whilst the internal slide is nearly in the same position as in Figure 12; thus
the steam is cut off, and this may be effected at any part of the stroke by
the toggle joint action. Poth slides are drawn to the other end of their

page_text: stroke, as in Figure 14, and when the toggle joint is brought to a straight
position, as in Figure 12, the steam is again cut off, as in Figure 14, only at the
opposite end of the valve.
. Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried
into effect, I would observe, in conclusion, that I do not confine or restrict
myself to the precise details or arrangements which I have had occasion to
describe or refer to, as many variations may be made therefrom without de-
viating from the principles or main features of my said Invention; but what
I consider to be novel and original, and therefore claim as the Invention
secured to me by the herein-before in part recited Letters Patent, is,―
First, the system or mode of arranging and canstructing valves, wherein
they are not subjected to unbalanced pressure at any point of their stroke or
travel, as herein-before described.
Second, the system or mode of actuating valves by means of spindles or
connections, which are lengthened and shortened by the working action, for
the purposes herein-before described.
In witness whereof, I, the said Robert Wilson, have hereunto set my
hand and seal, the Fifth day of March, One thousand eight hundred
and fifty-seven.
ROBERT WILSON. (L.S.)