A NEW OR IMPROVED SLIDE VALVE
Year: 1871

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LETTERS PATENT to Franklin Hocking and John Pinker, both of
Liverpool, in the County of Lancaster, Engineers, for the Invention
of "A NEW OR IMPROVED SLIDE VALVE."
Sealed the 9th April 1872, and dated the 13th December 1871.
PROVISIONAL SPECIFICATION left by the said Franklin Hocking and
John Pinker at the Office of the Commissioners of Patents, with
their Petition, on the 13th December 1871..
We, FRANKLIN HOCKING and JOHN PINKER, both of Liverpool, in
the County, of Lancaster, Engineers, do hereby declare the nature of
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the said Invention for "A NEW OR IMPROVED SLIDE VALVE," to be as
12
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follows:-
נדי
.
This Invention relates to the admission of steam into steam cylinders,
or the admission of gas, air, or other elastic fluid into the cylinders of"
other motive power engines where it may be desirable to have as little
friction as possible on the face of the slide valve.

page_text: Our Invention consists in a simple and improved means of reducing
the pressure on the face of the slide valve. This is done by incasing
the valve and passing the steam through a pipe or pipes; the said pipe or
pipes being connected to and leading directly between the-inner part of
the casing and the back of the valve; the said pipe or pipes to work in
a stuffing box or boxes in direct communication with the main steam
pipe or pipes connecting the engine or engines with the boiler or
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Franklin Hocking and John Pinker in the Great 1
Seal Patent Office on the 12th June 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, FRANKLIN
HOCKING and JOHN PINKER, of Liverpool, in the County of Lancaster,
Engineers, send greeting.
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WHEREAS Her most Excellent Majesty Queen Victoria, by Her 2
Letters Patent, bearing date the Thirteenth day of December, in the year
of our Lord One thousand eight hundred and seventy-one, in the thirty-
fourth year of Her reign, did, for, Herself, Her heirs and successors,
give and grant unto us, the said Franklin Hocking, and John Pinker,
Her special licence that we, the said Franklin Hocking and John Pinker, 2
our executors, administrators, and assigns, or such others as we, the said
-Franklin-Hocking and John Pinker, our 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 "A NEW OR IMPROVED SLIDE VAlve,”
upon the condition (amongst others) that we, the said Franklin

page_text: Hocking and John Pinker, our executors or administrators, by an
instrument in writing under our, 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 same was to be performed, and
5, 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.
T
.
NOW KNOW' YE, that we, the said Franklin Hocking and John
Pinker, do hereby declare the nature of our said Invention, and in what
manner the same is to be performed, to be particularly described and'
ascertained in and by the following statement:-
小
This Invention has for its 'object the admission of steam into steam
cylinders, or the admission of gas, air, or other elastic fluid into other
motive power engines where it may be desirable to have as little friction
as possible on the slide valve, it being a simple means of reducing the
pressure thereon, whereby the valve is effectually balanced with full
pressure, or with any variation of the main pressure steam.
Our Invention also relates to a simple means of combining the high
and low pressure valves for compound engines, whereby there may be
great economy in the expansion of steam in its passage from the high to
the low pressure cylinder.
I. Our Invention consists in a means of effectively balancing what.
may be termed an encased valve, that is to say, that the plain or
common slide valve is cast in combination with, and travels with its own
jacket. It will be understood therefore in any future reference hereafter
in this Specification that the combination of the slide valve and the
jacket will be called and considered the valve. Steam is led into the
valve through a trunk or trunks, pipe or pipes, which trunk or trunks,"
pipe or pipes, are connected to the valve and work in stuffing boxes.
The said stuffing boxes and trunks or pipes are so arranged as to be
adjustable if required should any unequal wear take place.
In order that the nature of this Invention, and the means by which
the same is effected, may be particularly described and ascertained this
Specification is accompanied by a Sheet of Drawings having figures and
letters of reference marked thereupon.
.ff
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page_text: In these Drawings our-Invention is shewn as applied to a steam
engine, Figure 1 being an external elevation; Figure 2, a sectional
elevation; Figure 3, a section at E, F, of Figure 2; Figure 4, a section
at A, B; and Figure 5, a section at C, D, of Figure 2.
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The balance of pressure required on the back of the valve to counter-
balance the back pressure exerted against the valve through the steam
ports is obtained by the admission of full pressure steam into a recess a
in the back of the slide valve, or the recess may be in connection with
the part casing or frame b, which is arranged to resist the pressure
exerted within the recess, and on the back. of the valve a ring piston c is
fitted into the recess on the back of valve or part casing or frame.
Springs d are fitted between the piston and the back of the valve as a
means of keeping the valve and piston in their proper working positions
when steam pressure is off the valve. Full pressure steam is admitted
into the recess a and under the piston c through a hole e in the back of
the valve, and in direct communication with full pressure.steam. from
the inner part of the valve f. The said recess is arranged sufficiently.
large in area to contain a total pressure slightly preponderating over
that exerted against the cylinder face g, g, g, thereby at any variation of
the main pressure steam the preponderance of pressure on the back of
the valve is self-maintained,. and tends at any variation of the main
pressure steam to keep the valve-face to its proper working position.
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II. The second part of our Invention, the combination of the high
and low pressure slide valves for compound engines, having for its
object economy in the expansion of steam in its passage from the high
to the low pressure valves, is effected by means of connecting 'the high-
and low pressure,valves together by a pipe or pipes h, h, leading direct
from the exhaust port of the high pressure valve to the steam ports-k-
of the low pressure valve... The said steam pipe or pipes are passages for
the travel of the steam that passes from the high pressure to the low
pressure valve, and these pipes travel with with the motion of the valves:
The combined valves need-only-be encased in a light casing for the
-purpose of carrying away any slight accumulation of steam that may
-have-passed the slide-faces. We do not confine ourselves to holding-the
combined-valves.in position entirely with the pipes connecting-the-steam_
passages of the two valves, but they may be connected-by-adjustable-
rods: The steam pipes may be of copper or of any other flexible metal,
and may be provided with any suitable arrangement for expansion and
d
"

page_text: contraction that will yield to any required adjustment with the adjusting
rods. We do not confine ourselves to the use of the ring piston; a solid
piston may be used instead, and steam may be led into the recess by
means other than through the back of the valve.
It will be seen by the foregoing description that by the adoption of
this Invention the following great advantages are offered, namely:-
Firstly, that the valves need not be enveloped in a full pressure steam
casing, but only such as may be needed for the purpose of carrying away
any slight escape of steam that may pass the working faces of the
valves; secondly, the valves are accessible when at work; thirdly, a
more direct passage is obtained for the steam from the high pressure to
the low pressure cylinders; fourthly, that a slight preponderance of
pressure is self-maintained on the back of the valve at any variation of
the main pressure of steam; and, fifthly, an economy in the expansion
of steam is obtained by the short distance the steam has to travel in its
passage from the high to the low pressure cylinder.
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Having now particularly described and ascertained the nature of our
said Invention, and the manner in which the same is to be carried into
effect, we wish it to be clearly understood that what we claim is the
application of a piston or pistons in the manner as herein-before
described in this Specification, or as in the accompanying Drawings
illustrated, whereby the slide valve is effectively balanced with full
pressure steam, or with any variation of the main pressure steam; also
the combination of the high and low pressure valves as herein described
and illustrated, whereby the steam is transmitted direct from the
exhaust ports of the high-pressure valve to the steam ports of the low-
pressure valve for compound or high and low pressure engines.
In witness whereof, we, the said Franklin Hocking and John Pinker,
have hereunto set our hands and seals, this Tenth day of June,
in the year of our Lord One thousand eight hundred and seventy-