IMPROVEMENTS IN CERTAIN PARTS OF STEAM ENGINES
Year: 1854

page_text: LETTERS PATENT to John Rogerson and James Brimelow, of Bolton, in
the County of Lancaster. Engineers, for the Invention of "IMPROVEMENTS
IN CERTAIN PARTS OF STEAM ENGINES."
Sealed the 20th March 1855, and dated the 28th September 1854.
PROVISIONAL SPECIFICATION left by the said John Rogerson and
James Brimelow at the Office of the Commissioners of Patents, with
their Petition, on the 28th September 1854.
We, JOHN ROGERSON and JAMES BRIMELOW. of Bolton, in the County of
Lancaster, Engineers, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN CERTAIN PARTS OF STEAM ENGINES," to be as follows:-
Our Invention relates to an improved method of working the slide valves of
steam engines, by which we reduce the pressure, and consequently the labour
of working the same. We propose to enclose the valve in a dome-shaped
chest, with an aperture at the top, through which we connect the piston rod to
a horizontal lever, and then by means of a vertical lever attached thereto it
can be worked with the greatest ense. We shall fix a tap to let off the con-
densed water, which tap is not shewn on the accompanying outline Drawing;
but the principle of our Invention will be clearly understood therefrom.
represents the slide valve; b, the piston rod; c, the horizontal lever; d, the
vertical lever; e, the working handle or lever; and f, the dome-shaped chest.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Rogerson and James Brimelow in the Great Seal
Patent Office on the 26th March 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JOIN
ROGERSON and JAMES BRIMELOW, of Bolton, in the County of Lancaster,
Engineers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Royal
Letters Patent, bearing date the Twenty-eighth day of September, in the year
of our Lord One thousand eight hundred and fifty-four, in the eighteenth
year of Her reign, did, for Herself, Her heirs and successors, give and grant
unto us,, the said John Rogerson and James Brimelow, Her special licence
that we, the said John Rogerson and James Brimelow, our executors,
administrators, and assigns, or such others as we, the said John Rogerson
and James Brimelow, our exccutors, 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 "IMPROVE-
MENTS IN CERTAIN PARTS OF STEAM ENGINES," upon the condition (amongst
others) that we, the said John Rogerson and James Brimelow, by an
instrument in writing under our hands and seals, or under the hand and seal
of one of us, 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 Seal Patent Office within six calendar months
next and immediately after the date of the said Royal Letters Patent.
NOW KNOW YE, that I, the said James Brimelow, for and on behalf of
myself and the said John Rogerson, do hereby declare the nature of the said
Invention, and in what manner the same is to be performed, to be par-
ticularly described and ascertained in and by the following statement (that
is to say):-
Our Invention relates to an improved method of working the slide valves of
steam engines, so as to counteract or reduce the pressure on them, thereby pre-
venting loss of power, and acquiring the facility to move them with ease and
rapidity, by which we obtain great advantages, and especially to those engines
where reverse motions are frequently required.
Our said Invention consists, firstly, in connecting with the slide valve a
piston with a dome, so formed as to be able to employ a long connecting rod.

page_text: Secondly, in surrounding the piston with a steam-tight casing, for the pur-
pose of preventing the exit of the steam or condensed water, except through a
tap provided for the purpose.
And, thirdly, in the application of weighted levers, either simple or com-
pound, for the purpose of more accurately adjusting the counteracting force.
These our said improvements will be clearly understood by reference to the
accompanying Sheet of Drawings, in which the same letters of reference are
used to represent the same parts in both the Figures. Fig. 1 is an outside
view, and Fig. 2 a section, shewing part of the cylinder of a steam engine
with the slide box and our improvements attached.
a represents the slide
valve; b, the slide box, to which is attached the short cylinder c, in which the
lower part of the piston d works; e is the connecting rod working on the pins f
and g, attached to the slide valve a and the piston d; h is an external cover or
casing, made dome-shaped, and furnished at the top with a stuffing box i,
through which passes the rod k, having one end attached to the upper part of
the piston d, and the other to the lever 1, working on its fulcrum m. To the
lever one end of the connecting rod n is attached, and the other to the lever o,
working on its fulcrum p, and furnished with a weight q, which can be shifted
as desired. The rod k not only forms the connection between the lever and
the piston d, but causes the latter to have parallel motion. The piston aloue
can be adjusted to counteract the weight upon the slide valve, by making it of
nearly equal surfaces to the latter; but it is found more convenient to make it
considerably less, and make up the deficiency by the employment of compound
levers, as shewn in the Drawing, when high-pressure steam is employed.
When the steam is of low pressure, the weight r, shewn by the dotted lines,
can be attached to the lever l. The condensed water is taken off by the tap s.
The action of the arrangement is as follows:-The steam from the boiler
enters the slide box, and acting equally in all directions, presses with a force
corresponding to its surface upon the slide valve and also upon the piston,
which, in the ratio of its surface, resists or takes off the weight upon the slide
valve, by means of the connecting rod. It is evident that what further may be
required can be obtained by the lever or levers. The improved arrangement
can be applied to vertical cylinders by altering the form of the levers and
making them bell-crank shape.
Having thus fully described the nature and particulars of our said Invention,
we desire it to be distinctly understood that we do not confine ourselves to the
exact details herein set forth, as such may be varied or modified without
departing from the principle thereof; but we claim as our Invention, and

page_text: which, to the best of our knowledge and belief, has not been hitherto used
within this realm,-
Firstly, the parallel motion of the piston, by its sliding in a cylinder at the
bottom, and having a guide or stuffing box at the top.
Secondly, the dome of the piston, in order to obtain a long connecting rod.
And, thirdly, the casing of the piston, to carry the stuffing box and top
fulcrum.
In witness whereof, I, the said James Brimelow, have hereunto set my
hand and seal, this Twenty-fourth day of March, One thousand eight
hundred and fifty-five.
JAMES BRIMELOW. (L.8.)
Signed, sealed, and delivered by the within-
named James Brimelow, in the presence of
E. J. HUGHES,
Patent Agent,
Manchester.