IMPROVEMENTS IN THE SLIDE VALVES OF STEAM ENGINES AND STEAM HAMMERS
Year: 1875

page_text: LETTERS PATENT to Robert Fawcett and John Edwin Firth, both of
Leeds, in the County of York, for the Invention of "IMPROVEMENTS
"
PROVISIONAL SPECIFICATION left by the said Robert Fawcett and
John Edwin Firth at the Office of the Commissioners of Patents,
with their Petition, on the 25th March 1875.
We, ROBERT FAWCETT and JOHN EDWIN FIRTH, both of Leeds, in the
County of York, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE SLIDE VALVES OF STEAM ENGINES AND STEAM HAMMERS,"
to be as follows:-
Our Invention has particular reference to those steam hammers or
steam engines which have hitherto been provided with cylindrical slide
valves, but it may also be applied to other steam hammers or steam
engines having other forms of slide valves, and is as hereafter described.

page_text: We employ a valve of either a single or a double V shape; this is
fitted so as to work freely in a V shape bed, which may either be cast
solid on the cylinder or fixed thereto. In the V shape bed we have a
port or ports to each end of the cylinder, as well as for the exhaust
steam. In order to keep the valve on to the face we employ a valve
cover, which is made either a V or other form to suit the external con-
struction of the valve. This cover is secured to the V bed by bolts or
other suitable well known means.
By the above construction of valve bed and cover the valve is relieved
from all side pressure of steam.
We by preference make the valve solid at its ends, which are con-
nected by a hollow boss in the centre.
The steam may be admitted to the cylinder from the outside ends of
the valve and exhaust through the centre, or vice versa.
The valve is actuated in the ordinary manner, care being taken when
employed for steam hammers that the weight of the levers and other
parts for imparting the motion thereto should equally balance the valve
when fixed in position.
The valve can be easily kept in good repair and steam-tight by
following it up to the face of the V bed as it wears with the valve
cover.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Robert Fawcett and John Edwin Firth in the
Great Seal Patent Office on the 25th September 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, ROBERT 2
FAWCETT and JOHN EDWIN FIRTH, both of Leeds, in the County of
York, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fifth day of March, in the year
of our Lord One thousand eight hundred and seventy-five, in the thirty- 3
eighth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto us, the said Robert Fawcett and John Edwin

page_text: Firth, Her special licence, that we, the said Robert Fawcett and
John Edwin Firth, our executors, administrators, and assigns, or such
others as we, the said Robert Fawcett and John Edwin Firth, 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 THE SLIDE VALVES OF STEAM ENGINES AND STEAM HAMMERS,"
upon the condition (amongst others) that we, the said Robert Fawcett
and John Edwin Firth, 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 cause the
same to be filed in the Great Scal Patent Office within six calendar
months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that we, the said Robert Fawcett and John
Edwin Firth, 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 thereof, that is to
say :-
Our Invention has particular reference to those steam hammers or
steam engines which have hitherto been provided with cylindrical
slide valves, but it may also be applied to other steam hammers or
steam engines having other forms of slide valves, and is as hereafter
described.
We employ a valve of either a single or a double V shape; this is
fitted so as to work freely in a V shaped bed, which may either be cast
solid on the cylinder or fixed thereto. In the V shape bed we have a
port or ports to each end of the cylinder as well as for the exhaust
steam. In order to keep the valve on to the face we employ a valve
cover, which is made either a V or other form to suit the external
construction of the valve. This cover is secured to the V bed by bolts
or other suitable well-known means.
By the above construction of valve bed and cover the valve is relieved
from all side pressure of steam.

page_text: thus allowing the piston to descend. To raise tho piston again it is only
required to move the valve by the aid of levers or other equivalent
means until the ports c (Figs. 6 and 7) are open to admit tho steam from
the steam chest b, when the ports c will be open for the steam to escape
from the top side of the piston, as in the case of steam escaping from
the bottom or under side.
In Figs. 2, 3, 4, and 5, Sheet 1, we shew our plan of admitting the
steam to the cylinder from the hollow chamber or inside of the valve f.
The steam from the boiler in this case after passing through the throttle
valve box a is made to pass into the belt pipe g (Figs. 2, 4, and 5), and
thence into the valve chamber. The ports or steamways c (Figs. 4
and 5) being open to the chamber the steam passes through them along
the pipe d, and so on to the top side of the piston, whilst the ports e
being open at the same time to the steam chests 6 (Figs. 2, 3, 4, and 5,)
the steam from the under side of the piston can escape along the pipe i
(Fig. 5) through the ports e (Figs. 4 and 5) into the steam chest b.
(Figs. 2, 3, 4, and 5), thence through the ports and belt pipes m (Figs. 3,
4, and 5,) round the cylinder into the exhaust h (Figs. 2, 3, and 4), and
so allowing the piston to descend. To raise the piston the valve ƒ must
be moved by levers or other equivalent means until the ports e (Figs. 4
and 5) be opened to the valve chamber to admit steam to the under
side of the piston, the ports c will at the same time be open to the steam
chest b, thus allowing the steam to escape from the top side of the piston
and round the belt pipes m as before, the exhaust steam being utilized
in this manner to keep up the temperature of the cylinder itself, and thus
preventing to a great extent the condensation of the steam in the
cylinder, and forming by the belts 7 and m (Figs. 2, 3, 4, and 5,) a steam
jacketed cylinder.
We would here remark that although we have only shewn our Inven-
tion as applied to steam hammers and steam engines, it is equally
applicable for other purposes where an ordinary slide valve is used.
Having now declared the nature of our said Invention, and shewn
by Drawings a convenient manner of carrying the same into operation,
we would have it understood that we do not limit ourselves to the precise

page_text: departing from our Invention, but what we do claim and desire to be
secured to us by Letters Patent is, the arrangement, construction, and
application of the herein-described slide valve (with modifications of the
same) and parts connected therewith, to steam hammers and steam
engines, substantially as herein set forth.
In witness whereof, we, the said Robert Fawcett and John Edwin
Firth, have hereunto set our hands and seals, this Twenty-fourth
day of September in the year of our Lord One thousand eight
hundred and seventy-five.
R. FAWCETT.
(L.S.)
JOHN EDWIN FIRTH. (L.S.)