IMPROVEMENTS IN THE SLIDE VALVES OF STEAM ENGINES
Year: 1877

page_text: LETTERS PATENT to Elizabeth Dooley, of 52, Weston Street, Bermondsey, in
the County of Surrey, Adininistratrix of John Dooley, late of Erith, in the
County of Kent, Engineer, deceased, for the Invention of "IMPROVEMENTS IN
THE SLIDE VALVES OF STEAM ENGINES."
Sealed the 29th January 1878, and dated the 31st July 1877.
PROVISIONAL SPECIFICATION left by the said John Dooley at the Office of
the Commissioners of Patents on the 31st July 1877.
JOHN DOOLEY, of Erith, in the County of Kent, Engineer.
THE SLIDE VALVES OF STEAM ENGINES."
"IMPROVEMENTS IN
The object of this Invention of improvements in the slide valves of steam engines
is to arrange the valve in such manner that the pressure of the steam upon it as it
traverses to and fro is counteracted, and the valve is so balanced that its motion may
be made as free as that of a pendulum.
.
One mode of arranging this balanced valve is as follows:-The valve chest, to
which the steam bas access, is made with an opening at the upper part immediately
over the ports. This opening is surmounted by a conical or other suitably shaped
steam chamber, the flange on the lower part of which is bolted down to the valve
chest. The upper part of this chamber is open and flanged to admit of a shallow cup-
like cylinder being fitted thereto and secured by bolts. The open part of this cylinder
is fitted with a piston, the upper face of which is open to the atmosphere, and its
periphery is maintained perfectly tight by means of a leather collar, similar to the cup
leather of a hydraulic pump or other similar machine. This leather is bolted up to
the under side of the piston, from whence it bends downwards at right angles, and
presses against the inner face of the cylinder. A short piston rod is suspended by
a nut from the centre of the piston, and this rod extends through a stuffing box in
the bottom of the cylinder, to which is attached a connecting rod with a joint at
Price 6d1

page_text: each end. One end is attached to lugs on the back of the valve, and the other to
the bottom of the piston in the upper part of the chamber before referred to, so that
the valve thus supported is as free to swing to and fro as if it formed the bob of a
pendulum.
The cylinder is at all times kept full of oil, glycerine, or other suitable fluid, and
it communicates at the lower part with a coil of pipe (by preference a double coil)
that encircles the conical steam chamber. This coil terminates in a vertical siphon
bend pipe, the lower end of which opens into the valve chest. The cylinder and
the coil are kept full of oil, glycerine, or other fluid, so that the steam has no access
thereto, nevertheless it exerts its pressure upon the oil or other fluid through the
vertical siphon bend just referred to. The coil serves as a reservoir for the oil or
other fluid so as to ensure a constant supply. In this way, as the slide valve moves
to and fro over the ports, a certain amount of motion is imparted through the link
on the back of the valve to the piston in the cup cylinder above, and thus the oil,
glycerine, or other fluid contained in the cup cylinder acts as a self-adjusting elastic
diaphragm, allowing the utmost possible freedom to the valve, which slides to and fro
like the bob or weight hung upon a pendulum, and with only just sufficient counter-
balance to keep the ports steam-tight. It is obvious that this mode of suspending
the slide valve secures the utmost freedom of motion combined with the minimum of
friction, thus effecting an important economy in power as well as in wear and tear.
The foregoing arrangement may be varied in many ways to suit the particular
class of engine to which it is applied.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Elizabeth Dooley in the Great Seal Patent Office on the 31st January
1878.
ELIZABETH DOOLEY, of 52, Weston Street, Bermondsey, in the County of Surrey,
Administratrix of John Dooley, late of Erith, in the County of Kent, Engineer,
deceased. "IMPROVEMENTS IN THE SLIDE VALVES OF STEAM ENGINES."
The object of this Invention is to arrange the slide valves of steam engines in
such manner that the pressure of the steam is counteracted, so as to permit of their
moving to and fro as freely as a pendulum.
And in order that this Invention may be properly understood, and, if required,
carried into effect, I will now proceed to describe the two modifications of the
improved valves which are shewn in the accompanying Drawing.
Figure 1 is a vertical section of one arrangement; and Figure 2, a plau corre-
sponding thereto.
The valve chest A has at its upper part an opening B, which is immediately over
the ports C. This opening B is surmounted by a conical or other suitably shaped
steam chamber D. The flange on the lower part of this chamber is bolted down to
the valve chest A, and the upper part is also flanged to admit of the shallow
cylinder E, being fitted thereto. The open part of this cylinder is furnished with a
piston F, the upper face of which is open to the atmosphere, and its periphery is
maintained perfectly fluid-tight by means of the leather collar G, which is similar
to the cup leather of a hydraulic pump, or this part may be made of any other
suitable material. The collar is bolted to the under side of the piston F, and is
then bent downwards at a right angle and presses against the inner face of the
cylinder E, and thus keeps the junction of the piston fluid-tight. A short piston
rod H is suspended by a nut from the centre of the piston F. This rod extends
through a stuffing box or gland I in the bottom of the cylinder E, where it is
attached to the link K. This link is connected by a pin joint at the upper end to
the piston rod H, and at the lower end it is secured to lugs on the back of the slide
valve L. By means of this arrangement the valve L is as free to swing to and fro
as if it formed a portion of a pendulum. The ordinary valve rod M passes through
a gland N at the end of the valve box A in the usual way. The cylinder E com-
municates at its lower part with the tubular coil O which encircles the conical
steam chamber D. It is preferred that this tube should form a double coil or spiral
around the chamber D, as shewn in Figures 1 and 2, and its remaining part
terminates in a vertical syphon bend P, which is carried upwards a little above the
cylinder E, its lower extremity entering the valve chest A. This part is furnished
with a steam cock at P¹, by which the flow of steam may be regulated as required.
The cylinder E and the coil O are kept full of oil, glycerine, or other suitable
non-evaporative fluid, which acts as a liquid spring on the piston F, and through it
on the valve L. The lifting of the piston. F, by which the pressure of the valve L
upon its seat is regulated, is obtained by the admission of the steam through the
syphon P controlled by the cock P¹. Thus the horizontal coil O serves as a reservoir
or magazine, to ensure at all times a constant supply of oil to the cylinder. The
oil or other fluid is supplied to the cylinder E from time to time by means of the
feed cup Q, so that the quantity contained in the cylinder and coil may be regulated
as required.
The modification delineated in Figure 3 of the accompanying Drawing shews the
improvements applied to a vertical engine, and a mode of arranging the fluid regu-
lator E at any convenient distance from the valve chest A. The parts of this
arrangement which are similar to those in Figures 1 and 2 are marked with corre-
sponding letters of reference. Here the cylinder E is supposed to be placed at some
distance from the valve chest A, which has bolted to it the box D. The piston F
is connected by the rod H to the bell-crank lever R, which is arranged outside the
box or steam chamber D, its upper extremity being connected by a link S (through

page_text: .
a stuffing box) to the link K and valve L. The pipe O is the equivalent of the
coil before described, and the supply of oil and admission of steam is regulated in
like manner. This arrangement of the balance regulator admits of its being placed
in any convenient part of an engine or practical distance from the engine itself.
With these improvements, as the slide valve moves to and fro over the ports, a
certain amount of motion is imparted through the links to the piston F, and the
fluid beneath it acts as a self-adjusting elastic diaphragm, allowing the utmost
freedom of motion to the valve, it having only just sufficient counterbalance to keep
the parts steam-tight, thus effecting an important economy of power, as well as
saving wear and tear.
Having now described the nature of the said Invention, and in what manner the
same is or may be carried into practical effect, I desire it to be understood that what
I believe to be new, and therefore claim under the herein-before in part recited
Letters Patent is,―
Firstly. The general arrangement, construction, and combination of parts forming
the improved balance slide valves for steam engines, substantially as herein-before
described, and shewn in the accompanying Drawings, or any mere mechanical
modification of the said arrangements.
Secondly. The method of using and applying oil, glycerine, or other similar
suitable liquid to act as an elastic diaphragm or spring in balance slide valves, as
herein-before described, and shewn in the accompanying Drawings.
In witness whereof, I, the said Elizabeth Dooley, have hereunto set my hand
and seal, this Thirty-first day of January, in the year of our Lord One
thousand eight hundred and seventy-eight.
ELIZABETH DOOLEY. (L.S.)