IMPROVEMENTS IN THE SLIDE VALVES OF PRIME MOVERS
Year: 1876

page_text: LETTERS PATENT to George Alexander Calvert, of Liverpool, in the County of
Lancaster, Engineer, for the Invention of "IMPROVEMENTS IN THE SLIDE
VALVES OF PRIME MOVERS."
Scaled the 10th November 1876, and dated the 18th May 1876.
PROVISIONAL SPECIFICATION left by the said George Alexander Calvert
at the Oflice of the Commissioners of Patents on the 18th May 1876.
GEORGE ALEXANDER CALVERT, of Liverpool, in the County of Lancaster,
Engineer. "IMPROVEMENTS IN THE SLIDE VALVES OF PRIME MOVERS."
This Invention relates to equilibrium slido valves in which a ring is employed,
against which the back of the slide valve works, the interior of the said ring
opening to the atmosphero or to the condenser.
Heretofore the said ring has been stationary, and has been kept up against the
back of the slide valve by springs or their equivalents. Now it has been found in
practice that such rings are liable to stick fast through the action of rust, salt,
burnt oil, or tallow, the result being that as the surfaces of the valve and ring wear
steam begins to pass to the atmosphere or to the condenser so as to impair the
vacuum.
Now my Invention provides means whereby the said defects are overcome, and
consists in preventing the sticking of the said ring by giving a to-and-fro motion
thereto at right angles to the motion of the valve.
In carrying my Invention into practico I fit the said ring so that it can work
up and down through a stuffing box, and form the slide valve taper or wedge shape
from back to front, so that in its longitudinal to-and-fro motion an upward and
downward motion is given to the said ring, which is kept in contact with the valve
by means of springs or their equivalents. When the interior of the ring opens to
the condenser à test cock shows when the stuffing gland is too slack by the passage
of steam, and a pin or its equivalent attached to the ring and projecting
through a stuffing box shows by its motion being arrested that the gland is too
tight.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said George Alexander Calvert in the Great Seal Patent Office on the
18th November 1876.
.
GEORGE. ALEXANDER CALVERT, of Liverpool, in the County of Lancaster,
Engineer. "IMPROVEMENTS IN THE SLIDE VALVES OF PRIME MOVERS."
This Invention relates to equilibrium slide valves in which a ring is employed,
against which the back of the slide valve works, the interior of the said ring
opening to the atmosphere or to the condenser.

page_text: Heretofore the said ring has been stationary, and has been kept up against the
back of the slide valve by springs or their equivalents.
Now it has been found in
practise that such rings are liable to stick fast through the action of rust, salt,
burnt oil, or tallow, the result being that as the surfaces of the valve and ring
wear steam begins to pass to the atmosphere or to the condenser so as to impair
the vacuum.
Now my Invention provides means whereby the said defects are overcome, and
consists in preventing the sticking of the said ring by giving a to-and-fro motion
thereto at right angles to the motion of the valve.
In carrying my Invention into practice I fit the said ring so that it can work
up and down through a stuffing box, and form the slide valve taper or wedge shape
from back to front, so that in its longitudinal to-and-fro motion an upward and
downward motion is given to the said ring, which is kept in contact with the valve
by means of springs or their equivalents.
When the interior of the ring opens to
the condenser a test cock shows when the stuffing gland is too slack by the
passage of steam, and a pin or its equivalent attached to the ring and projecting
through a stuffing box shows by its motion being arrested that the gland is too
tight.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 is a longitudinal sectional elevation illustrative of my Invention.
1, cylinder ports; 2, slide valves; 3, equilibrium ring resting on the back of the
valve 2, and inaintained in position by the springs 4 in the groove 5 in the valve
chest cover 6. The valve 2 is made taper or wedge shape, so that whilst moving
to and fro it shall give an up-and-down motion in the grooves 5 to the said ring 3.
This arrangement is applicable to existing valves.
Fig. 2 is a longitudinal sectional elevation showing two further modifications
under my Invention; 7, wedge shaped or taper valve; 8, 81, ring formed with the
flange 9, 94
The pressure of the steam on the flange 9, 91, assisted by the
spring 10, 101, keeps the said ring up to the valve. The ring 8 is shown fitting
and working in the stuffing box or gland 11. The ring 8 is shown formed as a
piston, and working in the cylinder 11. The small pin or stud 12 fixed to the
ring 8, and passing through the cover 13, serves to show when the ring is in
motion.
Fig. 3 is a sectional elevation of a further modification in which the cover 14 is
wedge shaped. The ring 15 in this case works in the groove 16 in the back of
the valve 17.
In all these views the space 18 enclosed by the ring opens to the condenser or to
the atmosphere.
Having now described the nature of my said Invention so that others will be
enabled to carry the same into practice, 1 claim the improvements substantially as
herein set forth.
In witness whereof, I, the said George Alexander Calvert, have hereunto set
my hand and seal, the Sixteenth day of November, in the year of our
Lord One thousand eight hundred and seventy-six.
Witness,
J. JOHNSON,
Patent Office,
Clayton Square,
Liverpool.
GEO. A. CALVERT. (L.S.)