IMPROVEMENTS IN APPARATUS APPLICABLE TO STEAM BOILERS TO OBTAIN GREATER SECURITY AGAINST EXPLOSION
Year: 1859

page_text: LETTERS PATENT to Thomas Green, junior, of Old Broad Street, in the
City of London, for the Invention of "IMPROVEMENTS IN APPARATUS
APPLICABLE TO STEAM BOILERS TO OBTAIN GREATER SECURITY AGAINST
EXPLOSION."
Sealed the 4th November 1859, and dated the 9th May 1859.
PROVISIONAL SPECIFICATION left by the said Thomas Green at the
Office of the Commissioners of Patents, with his Petition, on the
9th May 1859..
I, THOMAS GREEN, junior, of Old Broad Street, in the City of London, do
hereby declare the nature of the Invention for "IMPROVEMENTS IN APPARATUS
APPLICABLE TO STEAM BOILERS TO OBTAIN GREATER SECURITY AGAINST EXPLOSION," to
be as follows:-
This Invention has for its object improvements in apparatus applicable to
steam boilers to obtain greater security against explosion. For these purposes
the feed water in its passage to a steam boiler acts on a piston in such manner
as to prevent the piston being pressed downwards, which in itself is not new;
but in this arrangement the other side of the piston is constantly pressed on
by steam, there being a communication between the steam boiler and the
cylinder in which the piston works, at the same time the steam is prevented
sounding a whistle in connection with the cylinder so long as the supply of

page_text: water is properly kept up; so soon, however, as the supply of water fails, the
piston will be pressed down by the steam, and a valve of a steam whistle
(in connection with the piston) will be opened, and the whistle will be sounded
by the passage of steam through it. In order that the piston may be allowed
to descend or move as early as possible after the force pump has ceased to
supply water properly, there is a small outlet through which water is constantly
allowed to escape, and such outlet is by preference through a cone, the upper
and of which is small, so that no substance or matter can rest on the opening
so as to stop it.
Another part of the Invention consists in an arrangement of apparatus for
conducting the steam from a boiler into the fire-place when the water level
in the boiler falls below a certain point, and this is accomplished by means of
a plug or valve which closes the passage of a pipe leading from the upper part
of the boiler to the fire-place. This plug or valve is arranged to be opened
when a float in the boiler descends to a certain extent. For this purpose the
plug is acted upon by a lever, and such lever is acted on by a rod in connection
with the float. In constructing a safety valve having a spherical or curved
under surface (whether weighted below or above) I apply a disc above the
valve of larger diameter than the valve, and around the valve is a cup of
larger diameter than the disc, and the parts are so arranged that the disc
when the valve is closed descends some distance into the cup below the upper
edge thereof, leaving a small space between the edge or periphery of the disc
and the interior of the cup.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Green in the Great Seal Patent Office on the
9th November 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
GREEN, junior, of Old Broad Street, in the City of London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Ninth day of May, in the year of our Lord One
thousand eight hundred and fifty-nine, in the twenty-second year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Thomas Green, Her special licence that I, the said Thomas
Green, my executors, administrators, and assigns, or such others as I, the
said Thomas Green, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times thereafter

page_text: 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
APPARATUS APPLICABLE TO STEAM BOILERS TO OBTAIN GREATER SECURITY AGAINST
EXPLOSION," upon the condition (amongst others) that I, the said Thomas Green,
my executors or administrators, by an instrument in writing under my, 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 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 Thomas Green, do hereby declare the
nature of the 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 thereof, that is to say:-
This Invention has for its object improvements in apparatus applicable to
steam boilers to obtain greater security against explosion. For these purposes
the feed water in its passage to a steam boiler acts on a piston in such manner
as to prevent the piston being pressed downwards, which, in itself, is not new ;
but in this arrangement the other side of the piston is constantly pressed on by
steam, there being a communication between the steam boiler and the cylinder
in which the piston works, at the same time the steam is prevented sounding a
whistle in connection with the cylinder so long as the supply of water is
properly kept up; so soon, however, as the supply of water fails, the piston
will be pressed down by the steam, and a valve of a steam whistle (in con-
nection with the piston) will be opened and the whistle will be sounded by the
passage of steam through it. In order that the piston may be allowed to
descend or move as early as possible after the force pump has ceased to supply
water properly, there is a small outlet through which water is constantly
allowed to escape, and such outlet is by preference through a cone; the upper
end of which is small, so that no substance or matter can rest on the opening
so as to stop it.
Another part of the Invention consists in an arrangement of apparatus for
conducting the steam from a boiler into the fire-place when the water level in
the boiler falls below a certain point, and this is accomplished by means of a
plug or valve which closes the passage of a pipe leading from the upper, part
of the boiler to the fire-place. This plug or valve is arranged to be opened
when a float in the boiler descends to a certain extent. For this purpose the
plug is acted upon by a lever, and such lever is acted on by a rod in connection

page_text: with the float. In constructing a safety valve having a spherical or curved
under surface (whether weighted below or above) I apply à disc above the
valve of larger diameter than the valve, and around the valve is a cup of
larger diameter than the disc, and the parts are so arranged that the disc, when
the valve is closed descends some distance into the cup below the upper edge
thereof, leaving a small space between the edge or periphery of the disc and
the interior of the cup.
Having thus stated the nature of my Invention, I will proceed more fully to
describe the manner of performing the same.
DESCRIPTION OF THE DRAWINGS.
Figure 1 shews a section of apparatus constructed and combined according
to my Invention; Figure 2 is a plan thereof partly in section; and Figure 3 is
a transverse section thereof.
a is the inlet, connected with the force pump for supplying water to
a boiler, the water passing freely into the boiler so long as the passage is open
thereto by the float and valve used for that purpose, and the water passes
through the outlet 6 to the boiler or to an escape outlet when the supply is not
required to the boiler; c is a steam inlet communicating constantly with the
boiler, so that there will be a constant pressure of steam on the piston d tending
to force it downwards, whilst the pressure of water, if properly and con-
tinuously supplied by the force pump, will press on the under side of the piston d
and prevent it descending, but should any defect in the force pump or other
cause render the supply of water at a insufficient, then the pressure of the
steam on the upper side of the piston d will prevail, and the piston will be
caused thereby to descend and open the valve e to the whistle f. The
apparatus is arranged in such manner that the piston d may descend a distance
before it aots on the stem of the valve e, and this distance may be greater or
less according to the desire of the parties applying the apparatus; g is a conical
nipple through which there is a constant outgoing of a small quantity of water;
this cone is covered by a perforated shield in order to prevent any matters getting
to the conical outlet which would clog it; by this arrangement, should the force
pump cease to supply sufficient water, a quantity of the water would continue
to escape through the nipple, and the piston would immediately descend. I
would state that it is not new to cause the water fed to press on a piston so as
to prevent a whistle being sounded, I do not therefore claim the same, and I
would state that the peculiar character of this part of the Invention consists
in the combination of the parts a, c, d, and g.
In order to convey the steam of a steam boiler into the ash-pit when the

page_text: water falls below a certain point, and thus to damp the fire and relieve the
pressure on boiler by allowing the steam to blow off, I employ an apparatus
such as is shown at Figure 4, where h is a float in a steam boiler in connection
with a lever i, also within the boiler. The other end of this lever acts on a
slide valve j, or it may be arranged to act on any other suitable slide or valve;
k is an outlet which is connected with the ash-pit of the boiler furnace, by
which arrangement when the water level in the boiler sinks, the valve j will be
opened, and the steam will escape to the ash-pit.
I would state that this part of the Invention consists in the combination of
mechanical parts herein described. Figure 5 shows a safety valve and
apparatus constructed and combined according to another part of my Invention;
Z is valve having a spherical under surface; m is a disc of larger diameter than
the valve, so that any steam escaping beyond the valve will tend to press the
disc and valve upwards; n is a cup, the upper edges of which rise somewhat
above the disc, and there is a small space below the inner surface of the
cup, and the outer edge of the disc o is a weighted rod to the valve, and the
disc is also shewn to be weighted. I would state that the peculiarity of this
part of my Invention consists in the combination of the parts l, m, and n, as
herein described.
In witness whereof, I, the said Thomas Green, have hereunto set my
hand and seal, this Ninth day of November, in the year of our Lord
One thousand eight hundred and fifty-nine.
THOMAS GREEN, JUN. (L.S.)