IMPROVEMENTS IN SAFETY VALVES FOR STEAM BOILERS, AND IN STEAM ENGINES."
Year: 1854

page_text: LETTERS PATENT to William Hartley, of Bury, in the County of Lan-
caster, Engineer, for the Invention of "IMPROVEMENTS IN SAFETY VALVES
FOR STEAM BOILERS, AND IN STEAM ENGINES."
PROVISIONAL SPECIFICATION left by the said William Hartley at
the Office of the Commissioners of Patents, with his Petition, on the
18th December 1854.
I, the said WILLIAM HARTLEY, of Bury, in the County of Lancaster, Engineer,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
SAFETY VALVES FOR STEAM BOILERS, AND IN STEAM ENGINES," to be as follows:-
My improvements in safety valves consist in the employment of two valves
or pistons, one of which, being of superior area, keeps the outlet closed, until,
by excess of pressure, another loaded valve is opened and establishes an equi-
librium, thereby allowing the smaller valve or piston to open a suitable passage
for the escape of steam.
In order to illustrate this, I will describe a certain arrangement I employ.
The upper part of a suitably formed casing mounted upon the boiler is closed
by a valve or piston, the spindle of which carries another piston of greater
area, situate within a cylinder adapted to the interior, and dividing it into two
chambers; the upper side of this cylinder is open, and steam from the boiler

page_text: is therefore allowed to act upon the valve or piston therein, whereby it will
by means of its greater area keep the first-mentioned valve or piston down,
so as to close the aperture of the casing, and thus the several parts will remain
as long as the correct steam pressure shall exist; but upon an undue amount
taking place, a loaded valve adapted to the bottom of the cylinder will be
raised; steam will be admitted to the under side of the lower piston, and an
equilibrium will be established on either side thereof, so as to remove the
downward pressure from the upper valve or piston, which being still exposed
to a force of steam will rise from its seat or beyond suitable apertures, and
allow the required escape to take place. Upon the pressure sinking, the
loaded valve will fall, the steam under the larger piston escape through a
small aperture provided for the purpose, and the ceveral parts will regain
their former positions.
My improvements in steam engines are founded upon the principle of
the safety valve above described, the general character thereof consisting in the
employment of two pistons of unequal areas, within suitable cylinders, on
either side of the larger of which an equilibrium is established alternately,
with steam pressure on one side. By admitting steam between these pistons,
the larger area will be subjected to the greater pressure, and the piston will
be forced onward until at the end of the stroke, at which time, upon steam
being also admitted to the under side thereof, an equilibrium will be esta-
blished, and motion will be effected by steam pressure against the smaller
piston. By this arrangement it will be perceived that the steam between the
two pistons is never discharged. I have spoken of two pistons only, but it
will be evident that the engine may be compound if desired.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Hartley in the Great Seal Patent Office on the
16th June 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
HARTLEY, of Bury, in the County of Lancaster, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighteenth day of December, 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
me, the said William Hartley, Her especial license that I, the said William
Hartley, my executors, administrators, and assigns, or such others as I, the
said William Hartley, my executors, administrators, and assigns, should at

page_text: any time agree with, and no others, from time to time and at all times there-
after 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
SAFETY VALVES FOR STEAM BOILERS, AND IN STEAM ENGINES," upon the condition
(amongst others) that I, the said William Hartley, by an instrument in
writing under my hand and seal, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to be per-
formed, 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 Letters
Patent.
NOW KNOW YE, that I, the said William Hartley, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement and accompanying Drawing, that is to say: -
My Invention in safety valves consists in the employment of two valves or
pistons, one of which being of superior area keeps the outlet closed, until, by
excess of pressure, another loaded valve is opened, and establishes an equi-
librium, thereby allowing the smaller valve or piston to open.a suitable passage
for the escape of steam.
My Invention in steam engines is founded upon the principle of the safety
valves above mentioned, the general character thereof consisting in the em-
ployment of two pistons of unequal areas within suitable cylinders, on either
side of the larger of which an equilibrium is established alternately, with
steam pressure on one side. And in order that these improvements may
be fully understood, I have appended to this my Specification a Sheet of
Drawings, which I will now proceed to describe. One form in which the
improved safety valve may be employed is shewn in vertical section at Fig. 1,
in which a represents a pipe to be attached to the boiler; this pipe is provided
at 6 with a seat for a valve c, formed upon a tube d, which, after passing
through a partition e, carries a second valve or piston f, the upper side thereof
being within a chamber g, closed by a cover h. Between the partition e (which
acts as a guide) and the valve c, is an opening i, provided for the escape of
discharged steam; above the partition e, and beneath the valve f, is also an
opening j, leading to a chamber kc, within which is a valve 7, loaded to its
seat by a weight situate within the boiler, and exposed on its under side to the
The valve is formed with a
pressure of steam by means of a passage m.
cylindrical upper part, which projects into a chamber n, not quite steam-tight,
but allowing a little steam to pass into the said chamber, which is open to the

page_text: atmosphere. The operation is as follows:-According to the position shewn
in the Drawing, the steam is supposed to be within its intended pressure, and
the valve c is maintained on its seat; this is accomplished by steam from the
boiler passing through the pipe a and tabe d into the chamber g, and there
exerting its elastic force upon the valve f, which being superior in area to
that shewn at c, will necessarily effect the purpose; but upon an excessive
pressure taking place, then the small loaded valve will be lifted, and allow
steam to pass through the passage j into the space above the partition e,
whereby the under side of the valve f will be submitted to a pressure equal to
that which is transmitted to the upper side thereof, through the tube d, and
an equilibrium will be established. Under these circumstances, the valve c will
no longer be loaded by steam pressure, and will therefore be free to rise and allow
a discharge through the passage i. Upon the proper elastic force in the boiler
being regained, the loaded valve l will be carried to its seat; steam will then no
longer pass through the passage j, and that which remains beneath the valve f
will escape to the atmosphere through the chamber n; the equilibrium will
thus be destroyed, and the valve c, restored to the position shewn. I have
stated that the cylindrical part of the valve is not quite steam tight, but
nearly so, thereby allowing steam to pass into the chamber n, which is open
to the atmosphere; the object of this is to prevent the steam which passes
into the passage j from pressing upon its upper area, for if such were the case
it would necessarily be acted upon on the upper as well as the under surface
by the same pressure, and would therefore be forced to its seat, and become
inoperative; on the other hand, if it were exposed direct to the atmosphere,
the steam would blow off without passing beneath the piston f; it is not,
however, necessary that its connexion with the chamber n should be otherwise
than perfectly free, for if the surfaces be sufficiently close to each other to
prevent such an amount of steam from blowing off as would reduce the
pressure of that which operates beneath the valve f, they will be fitted accu-
rately enough for the purpose. Fig. 2 represents in vertical section a modi-
fication of the above-described principle, and Fig. 3 is a plan view in section.
In this instance, a chamber a, attached to the boiler, is provided with au
interior cylinder b, supported therein by radial parts b*, so as to allow steam
from the boiler to pass. Within this interior cylinder, and fitted to a seat
therein, is a piston valve c, formed upon a hollow spindle d, which carries at
its upper end a smaller piston valve e, situate within a cylinder f; this cylinder
is attached to a flange within the casing a, and is provided with a number of
slots
9. formed around its periphery. Within the hollow spindle d is situate
the upper cylindrical part of a small valve h, loaded by an interior weight to a

page_text: seat adapted to the bottom of the cylinder b, according to the position shewn;
steam is passing from the boiler between the outward part of the cylinder b,
and the casing a, and is exerting its expansive force upon the upper side
of the piston c, and under side of the piston c, the former of which being of
superior area, will keep the latter below the slots g of the cylinder f, but upon
an undue pressure taking place, the small loaded valve h will be lifted, and
steam will be allowed to pass so as to exert its force upon the under side of the
piston c, as well as upon the upper side, by which means, an equilibrium will
be established, and the piston e, being no longer steam loaded, will rise within
its cylinder above the bottoms of the slots g, through which a discharge will
consequently take place, and from thence through a pipe i to the atmosphere.
It will be observed in this case, as in the former, that the upper part of the
small valve h is open to the atmosphere through the interior of the. hollow
spindle d, but in such manner as to allow but a small portion of steam to
blow off.
That part of my Invention relating to steam engines is shewn at Figs. 4, 5, 6;
Fig. 4 being a vertical section; Fig. 5, a view of the right-hand side of Fig. 4,
with the cover of the valve box removed; and 6, a horizontal section. Two
cylinders a, b, of unequal areas, and attached to the same rod c, are situate
within cylinders d, e, the latter of which is open at bottom to the atmosphere.
The cylinder d is provided with a passage l, in communication with a pipe m,
leading from the steam boiler; this passage opens by ways g, h, to the top and
bottom of the cylinder, the former of which is capable of being closed by a slide
valve. The cylinder d has also an eduction chamber k formed on either side
of the passage 1, and through which steam may be allowed to pass when the
valve has been moved below the way g. Suppose the parts to be situate as
shewn in the Drawing, steam will flow from the boiler in the direction of the
arrow, and exert its expansive force upon the top of the piston a, the under
side thereof being also submitted to pressure by means of the opening h; the
piston a will therefore be in a state of equilibrium, and as the same amount of
pressure is exerted upon the lower piston b, the two will be caused to descend.
When at the bottom of the stroke, the slide valve 7 will have been shifted so
as to bring its upper part below the opening g, at the same time closing the
opening g, by which means the steam above the piston a will be allowed to
5 pass into the upper part of the valve box, and from thence through the
passages and pipe k*, to the atmosphere or to a condenser; at the same time
the elastic force of the steam will be exerted upon the under side of the
piston a, and upper side of the other piston b, through the opening h; but as
the former is of superior area, the two will be carried upward again into the

page_text: position shewn, by which time the slide valve will have been restored to its
former position, and the same movements will be repeated.
Having thus described and ascertained the nature of my said Invention, and
the manner in which the same is to be performed, I desire it to be understood
that I claim, as secured to me under the above in part recited Letters Patent,
Firstly, the employment of two valves or pistons, the one of superior area
and keeping the other closed by steam pressure until an equilibrium is esta-
blished by admitting steam to either side of the former; also the use of the
small supplementary loaded valve 7 for the purpose of admitting steam to
another valve, thereby rendering it in a state of equilibrium.
Secondly, as applied to motive power engines, the employment of two
pistons of unequal areas, on either side of the larger of which an equilibrium is
established alternately, with steam pressure on one side.
In witness whereof, I, the said William Hartley, have hereunto set my
hand and seal, this Fifteenth day of June, in the year of our Lord
One thousand eight hundred and fifty-five.
WILLIAM HARTLEY. (L.S.)