CERTAIN IMPROVEMENTS IN STEAM ENGINES
Year: 1867

page_text: LETTERS PATENT to Edward Wood, of the Firm of John and Edward
Wood, of Bolton, the County of Lancaster, Engineers, for the Invention
of "COMAIN IN
PROVISIONAL SPECIFICATION left by the said Edward Wood at the Office
of the Commissioners of Patents, with his Petition, on the 28th
November 1867.
I, EDWARD WOOD, of the Firm of John and Edward Wood, of Bolton, in
the County of Lancaster, Engineers, do hereby declare the nature of the said
Invention for "CERTAIN IMPROVEMENTS IN STEAM ENGINES," to be as follows:-
My Invention relates to that part of steam engines called slide valves used
for the supply of steam, and more particularly to the form of such valves
known as the "gridiron slide valve."
The improvements consist, first, in the combination of an ordinary "gridiron
valve" with certain mechanism for opening such valve, and by means of a
steam piston acting at right angles to the valve spindle for effecting the

page_text: "
closing of such valve, so as to cause the valve to cut off steam at a required
portion of the stroke. Upon a shaft which is also arranged to actuate the
exhaust valve an eccentric is secured, the rod or arm of which projects towards
the slide valve spindle, and the upper end thereof is slightly curved or bent
which bears or slides upon a bowl or pin secured upon an arm which is
adjustable by the "governor," and in the ower edge of the eccentric rod a
catch or notch is formed. To the outer end or crosshead of the "gridiron "
valve spindle connecting rods or links are attached, which connect the spindle
to a lever fixed on a short shaft, on the end of which is also another lever
which projects so that the knife edge formed at the end thereof comes in
contact with the long arm of the eccentric rod and takes into the notch or
catch, and the said arm is kept in contact therewith by means of a spring.
Thus, as the shaft carrying the eccentric revolves the arm rises and falls
sliding on the bowl of the adjustable arm, which is so adjusted as to permit the
knife edge on the valve lever to enter the notch and to allow the arm to draw
such lever downwards, and so through the other lever and link to open the valve,
but at the point regulated to cut off the supply of steam the bent end of the
arm rises on the bowl and lifts the notch out of contact with the knife edge,
and the valve is closed by the pressure of steam acting against a piston at
right angles to the valve spindle, such pressure being applied to the valve
spindle by means of a lever on the aforesaid short shaft and a connecting rod
connecting the piston rod therewith, the position of the bent end of the
arm on the bowl varying with the part of the stroke at which the cut off is
effected.
66
A second part of the Invention consists in the novel combination of a
"gridiron " valve with an intermediate slide valve placed between it and the
cylinder, and having only one "port," both valves being actuated by cams or
eccentrics by which combination the "gridiron ports" in the cylinder are
dispensed with, one port only being used in each end of the cylinder, the
"gridiron" valve acting on the inner valve to admit and cut off the supply of
steam, by which means the construction of the cylinder is simplified, and also
the valves may be arranged parallel with the length of the cylinder.
Thirdly, the improvements consist in the application and adaptation of the
well known air buffer called "dash pots" to the end or on any convenient
part of the valve spindle to prevent concussion when the valve is closed either
by the medium of steam weight or spring, or in the application of a steam
buffer arranged within the steam chamber or valve box, and applied to the
valve spindle for the same purpose.

page_text: And lastly, the Invention consists in the application of a steam cylinder
and piston for closing each steam valve of "Corliss engines" instead of springs
or weights.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Edward Wood in the Great Seal Patent Office on the 27th
May 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
WOOD, of the Firm of John and Edward Wood, of Bolton, in the County of
Lancaster, Engineers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-eighth day of November, in the year of our
Lord One thousand eight hundred and sixty-seven, in the thirty-first year
of Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Edward Wood, Her special license that I, the said Edward
Wood, my executors, administrators, and assigns, or such others as I, the
said Edward Wood, my executors, administrators, and 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 " CERTAIN IMPROVEMENTS
IN STEAM ENGINES," upon the condition (amongst others) that I, the said
Edward Wood, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, should particularly describe
and ascertain the nature of the said Invention, and in what manner the sanie
was to be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date of the
said Letters Patent.
NOW KNOW YE, that I, the said Edward Wood, do hereby declare the
nature of the said Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement
and accompanying Drawings (that is to say) :-
My Invention relates to that part of steam engines called slide valves, use.
for the admission and emission of steam, and more particularly to that form
or description of such valves known as the "gridiron slide valve."
The improvements consist in the combination of an ordinary "gridiron
valve" with certain mechanism for opening such valve, and by means of a
steam piston acting at right angles to the valve spindle, for effecting the

page_text: closing of such valve, so as to cause the valve to cut off steam at a required
portion of the stroke. Upon a shaft, which is also arranged to actuate the
exhaust valve, an eccentric is secured, the rod or arm of which projects towards
the slide valve spindle, and the upper end thereof is slightly curved or bent,
which bears or slides upon a bowl or pin secured upon an arm, which is
adjustable by the "governor," and in the lower edge of the eccentric rod a
catch or notch is formed. To the outer end or cross head of the "gridiron"
valve spindle connecting rods or links are attached, which connect the spindle
to a lever fixed on a short shaft, on the end of which is also another lever,
which projects so that the knife edge formed at the end thereof comes in
contact with the long arm of the eccentric rod and takes into the notch or
catch, and the said arm is kept in contact therewith by means of a spring.
Thus, as the shaft carrying 'the eccentric revolves the arm rises and falls,
sliding on the bowl of the adjustable arm, which is so adjusted as to permit
the knife edge on the valve lever to enter the notch, and to allow the arm to
draw such lever downwards, and so through the other lever and link to open
the valve; but at the point regulated to cut off the supply of steam the bent
end of the arm rises on the bowl and lifts the notch out of contact with the
knife edge, and the valve being entirely disconnected and liberated is closed
by the pressure of steam acting against a piston at right angles, or at
a convenient angle to the valve spindle, such pressure being applied to the
valve spindle by means of a lever on the aforesaid short shaft and a connecting
rod connecting the piston rod therewith, the position of the bent end of the
arm on the bowl varying with the part of the stroke at which the cut-off is
effected, and which or similar arrangements of mechanism may be termed a
trippet motion."
"
Another part of the improvements consist in the application and adaptation
of the well known air buffer called "dash pots," to the end or any con-
venient part of the valve spindle or any other part of the valve gear to prevent
-concussion when the valve is being closed either by the medium of steam
weight or spring, or in the application of a steam buffer arranged within the
steam chamber or valve box, and applied to the valve spindle or any other
part of the valve gear for the same purpose.
In order that the Invention may be better understood and explained in
detail, I have hereunto attached two Sheets of Drawings made upon a scale of
about one inch and a half to the foot.
Fig. 1 represents a transverse section of a horizontal steam cylinder supplied
with ordinary "
gridiron " slide valves, and to which is adapted the improved
arrangement of mechanism for actuating the same; Fig. 2 represents a side

page_text: elevation of the same; Fig. 3 represents a vertical section of an arrangement
of steam piston and cylinder to be employed for closing the valve when released
from the eccentric rod, and the adaptation of a steam buffer to prevent con-
cussion on the closing of such valve. Fig. 4 represents a similar arrangement
of apparatus for closing the valve by means of steam, in which air is employed
in the "dash pot" as a medium instead of steam for preventing concussion on
the closing of the valve. Figs. 5 and 6 represent an improved apparatus for
actuating the slide valves of steam engines as adapted to a vertical cylinder.
"
"
In Sheet 2, Fig. 1 represents an end view of a similar apparatus applied to
the "Corliss engine." The valves are opened and closed by the ordinary
trippet motion. In Figs. 1, 2, 3, 4, 5, and 6, a, a, is the cylinder of an engine,
b, the steam chest; c, the "gridiron slide valve ;" d, the slide valve spindle; and e,
the exhaust ports and valve. The eccentric f, secured to the rod 9, is employed
to actuate the gridiron slide valve c, by means of the following arrangement
of mechanism, and in such a manner that the amount of steam admitted into
the cylinder for expansion may be "cut off" by the valve at any required
portion of a strake that will be in accordance with the amount of power
required for driving purposes, a separate cam or eccentric being used to
actuate the exhaust valve. The rod or arm 9 projects upwards from the clip
or strap of the eccentric f towards the slide valve spindle d, a portion of
the upper end thereof being so curved or bent as to constitute the inclined
surface g¹, which bears or slides upon the bowl h and forms the termination
of the lever or arm i, which lever is secured to a shaft i actuated by the
governor," whereby the position of such bowl is varied or regulated, a catch or
projection being provided on the arm of the eccentric below the bent or
inclined surface g¹. In order to effect the opening and closing of the "gridiron
valve" c, so as to regulate the flow of steam into the cylinder, the cross head
of the valve spindle is connected by means of the rods m with one end of the
bell crank lever n, the opposite end of such lever at the point n¹ being turned
up so as to fit and catch beneath the notch k on the eccentric arm when it is
descending, by which contact during such descent the valve is opened and
admits steam. When sufficient steam is admitted the arm of the eccentric is
immediately disconnected or thrown off the notch or point n¹ of the lever n by
the position of the bowl, which is regulated or decided by the " governor,"
and as soon as the lever n becomes released it is forced upwards by means of
the steam ram or piston o in the cylinder p, seen in Figs. 3 and 4, arranged
at any convenient angle; or springs or weights may be employed so as to close
the valve, and the cranked lever n being connected therewith by the rod q,
"

page_text: the concussion is prevented by means of the "dash pot" or buffer o, as seen
in Fig. 3, by the employment of steam, which is admitted to the upper portion
above the piston through the channel or duct r. The arrangement for
preventing the concussion on closing the valve, as seen in Fig. 4, is effected
by air which enters the cylinder above the piston through the passage r. It
will thus be seen that the bent inclined surface of the eccentric arm during
its rise and fall will come into contact sooner or later with the bowl hin
descending, the position of which is regulated by the "governor," according
to the position into which the notch k is brought to come into contact with the
projection n', which in its descent forces down the lever n, and opens (through
the medium of rods connected to the valve spindle) the "gridiron " slide
valve ca certain distance for admitting steam, which is regulated according to
the duration of contact between the bent inclined surface and the adjustable
bowl h, which is determined by the governor. When the eccentric rod is
unhooked the steam ram or piston in connection with the lever n closes the
valve as described, the levers and rods in connection with the valve spindle
remaining disconnected and in disuse until again caught during the descent of
the eccentric arm, at which time the valve is again opened.
I would here remark that since the filing of the Provisional Specification
for my said Invention, I have ascertained that the second part of my Invention
as therein described is not so novel or original nor of such utility as I then
considered it to be, and I therefore hereby disclaim that portion of the
Invention.
Having now described the nature of the said Invention, together with the
method of carrying the same into practical effect, I wish it to be distinctly
understood that I claim,-
First. The combination of a gridiron slide valve with an arrangement of
mechanism called or used as a "trippet motion," the valve moving in a
direction at right angles to the length of the steam cylinder.
Secondly. The novel arrangement and construction of "gridiron valves" and
cylinders for steam engines wherein part of the cylinder constitutes the seating
or surface upon which the valves work or slide, by which means moveable
valve seatings and side pipes are dispensed with.
Thirdly. The combination of a gridiron slide valve with the well known
mechanical contrivance called a "dash pot," whether the parts so combined
be used with or without a trippet motion."
"
And, lastly. The addition and combination of steam or air buffers to pistons
for closing valves, the said buffers being of greater area than the pistons used for

page_text: such purpose as herein-before described, set forth, and fully illustrated in the
Drawings attached.
In witness whereof, I, the said Edward Wood, have hereunto set my
hand and seal, this Twenty-third day of May, in the year of our
Lord One thousand eight hundred and sixty-eight.
Witnessed by
JOHN L. DAVIES, C.E.
Office for Patents,
Manchester.
EDWARD WOOD. (L.8.)