IMPROVEMENTS IN VALVES FOR STEAM ENGINES
Year: 1867

page_text: LETTERS PATENT to William Black and Thomas Hawthorn, both of the
Town of Gateshead, in the County of Durham, for the Invention of
"IMPROVEMENTS IN VALVES FOR STEAM ENGINES."
Sealed the 29th May 1868, and dated the 2nd December 1867.
PROVISIONAL SPECIFICATION left by the said William Black and
Thomas Hawthorn at the Office of the Commissioners of Patents, with
their Petition, on the 2nd December 1867.
We, WILLIAM BLACK and THOMAS HAWTHORN, both of the Town of
Gateshead, in the County of Durham, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN VALVES FOR STEAM ENGINES," to be as
follows:-
Our Invention has for its object improvements in in forming and arranging.
the valves of steam engines where the pressure of the steam on such valves is
equalized. For this purpose we propose to cause the top and bottom passages
from the steam cylinder to be carried to annular spaces formed between two
cylinders, which cylinders constitute the valve case. These annular spaces are
made to communicate with the internal cylinder by means of openings arranged
diagonally. The valve which is cylindrical in shape has enlargements which
work in the internal cylinders, that portion of the valve which is between the
enlargements being somewhat smaller in diameter allows a free commu-
nication between the spaces at either end of the valve. The steam pipe
communicates with the valve case at one end, and the exhaust pipe with the

page_text: valve case between the enlargements, or this arrangement may be reversed.
In order to make these valves steam-tight a number of small grooves are cut
in the enlarged parts working in the internal cylinders containing the diagonal
passages, and lubricators are placed at proper positions for keeping these
grooves full of tallow, oil, or other lubricating material, which not only
diminishes the friction of the valves, but renders them sufficiently steam-
tight. These valves may be varied in arrangement, and may be either solid
or hollow, or in two parts connected together by a spindle. The passages
through which the distribution takes place we prefer to form with diagonal
openings into the casing of the valve, so that an equal wear may take place,
and so that the valve may not be grooved by its reciprocating movement, but
the openings may be of any other suitable shape.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Black and Thomas Hawthorn in the Great Seal
Patent Office on the 30th May 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, WILLIAM
BLACK and THOMAS HAWTHORN, both of the Town of Gateshead, in the
County of Durham, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Second day of December, 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 us, the
said William Black and Thomas Hawthorn, Her special licence that we, the
said William Black and Thomas Hawthorn, our executors, administrators,
and assigns, or such others as we, the said William Black and Thomas
Hawthorn, 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 "IMPROVEMENTS IN
VALVES FOR STEAM ENGINES," upon the condition (amongst others) that we,
the said William Black and Thomas Hawthorn, our executors or adminis-
trators, by an instrument in writing under our or their hands and seals, or
under the hand and seal of one of us or them, 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

page_text: Seal Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that we, the said William Black and Thomas Hawthorn,
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 thereof, that is to say:
Our Invention has for its object improvements in forming and arranging
the valves of steam engines where the pressure of steam on such valves is
equalized.
And in order that our Invention may be clearly understood and readily
carried into practice, will proceed to describe the Drawing hereunto annexed.
:
DESCRIPTION OF THE DRAWING.
Figure 1 shows a transverse section, and Figure 2 a longitudinal section of
an arrangement of a cylindrical slide valve for a steam engine constructed in
accordance with our improvements.
The passages from either end of the steam cylinder A are connected with
annular spaces c, d, formed between two internal cylinders e, f, and the valve
case g. e, f, are diagonal openings formed in the internal cylinders e and f,
and these openings act as communicating passages between the annular
spaces c, d, and the interior of the valve chamber, which is closed at either
end by means of the covers 95, 9. The valve h, which is cylindrical in shape
and open at either end, has enlargements which act as valve surfaces in the
internal cylinders e, f. The portion of the valve h which is between the enlarge-
ments allows a free communication between the spaces g', g², at either end of
the valve, and the valve is attached to and actuated by the valve rod h³ passing
through stuffing boxes in the covers 9³, 9. The steam pipe g³ communicates
with the valve case g at one end, and the exhaust pipe 9 with the valve
case g between the enlargements h2, h3, of the valve h, or this arrangement
may be reversed. In order to make these valves steam-tight a number of
small grooves * are cut around the enlarged parts h1, h2, where they move in
contact with the internal cylinders e, f; and lubricators i, i, are so placed
as to supply these grooves with tallow, oil, or other lubricating material, which
not only diminishes the friction of the valves, but renders them sufficiently
steam-tight. The passages through which the distribution of the steam takes
place we prefer to form with diagonal openings into the casing of the valve,
as shown, so that an equal wear may take place, and so that the valve may
not be grooved by its reciprocating movement, but the openings may be of
any other suitable shape.

page_text: We would here remark that the form and arrangement of the various parts
herein shown and described may be greatly varied, and that the valves may be
formed according to our Invention either hollow, as shewn, or in one solid
piece, or in two parts connected together by a spindle, as has been heretofore
practised.
But what we claim is so forming and arranging the valves of steam engines
when the pressure of the steam is equalized, that the steam is supplied to and
withdrawn from the cylinder through openings formed through internal cylin-
ders e, f, into annular spaces c, d, as herein shewn and described, the advantage
of the lap of the ordinary slide being maintained in the piston valve..
We also claim rendering cylindrical valves sufficiently steam-tight by means
of grooves supplied with a lubricating substance, as herein shown and
described.
In witness whereof, we, the said William Black and Thomas Hawthorn,
have hereunto set our hands and seals, this 28th day of May, in the
year of our Lord One thousand eight hundred and sixty-eight.
WILLIAM BLACK.
(L.B.)
THOMAS HAWTHORN. (L.S.)