IMPROVE- MENTS. IN SAFETY VALVES
Year: 1864

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields,
in the County of Middlesex, Gentleman, for the Invention of "IMPROVE-
MENTS. IN SAFETY VALVES."-A communication from abroad by Felix
1
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Sealed the 20th December 1864, and dated the 25th July 1864.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition, on the
25th July 1864.
I, JOHN HENBY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, Gentleman, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN SAFETY VALVES," a communication to me from abroad
by Felix Ménard, of Paris, in the Empire of France, Engineer, to be as
follows:-
This Invention relates to an improved construction and arrangement of
safety valve, suitable either for locomotive, stationary, or marine engine boilers
and for steam generators or compressed air or gas containers of all kinds, and
consists in the employment in combination with a safety valve of the regulated
size, according to the heating surface of the boiler of a small supplementary
valve operating as herein-after described. The main valve is entirely enclosed
in a chamber and is unconnected with any other' mechanism, thus dispensing
with levers, weights, and springs for holding it down. The valve seat may
consist of two concentric rings or bearing surfaces, between which are formed

page_text: the escape apertures for the steam, such apertures leading downwards to the
outside of the valve chamber. On one side of this chamber there is a passage
which leads from the upper part of the chamber above the main valve into a
second chamber situate on one side of the first chamber, in which second
chamber works the small supplementary valve herein-before referred to. An
opening is made in the bottom of the second chamber which communicates
directly with the interior of the boiler, and through this opening passes the
spindle or guide of the small valve, such spindle or guide being cut away or
grooved longitudinally to allow the steam to pass by it when requisite. A
portion at the lower end of this valve spindle is not grooved or cut away, but
is made to fit accurately inside the aperture leading to the boiler, so as to
close the same when the small valve is elevated. The small valve which is
situate at the upper end of the spindle or guide above referred to is held
down by the direct pressure of a fixed weight fitted thereto; so long as the
pressure in the boiler does not exceed the desired amount the small valve
will remain closed and the steam will be free to pass through the aperture in
the bottom of the second chamber, thence into the second chamber and along
the passage which leads to the upper surface of the main safety valve and con-
sequently that valve will be balanced by an equal pressure of steam above and
below; but should the pressure of the steam become unduly elevated, then
the small valve will be lifted and will cause the lower aperture leading into
the boiler to be shut. The steam which had previously balanced the main safety
valve will now escape into the atmosphere by the small valve, and as the
lower aperture leading to the boiler is closed the main safety valve, which
will be no longer balanced, will consequently be raised, and allow the steam
to escape freely until the reduction in the pressure has permitted of the closing
of the small valve again, when the balance of pressure on the main valve will
be restored, and the valve will return to its seat again. For the facility of
repairs it is proposed to tap the small valve seat into the second chamber so
that the valve and its seat may be readily removed and cleaned or repaired.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Henry Johnson in the Great Seal Patent Office
on the 25th January 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman, send greeting.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date, the Twenty-fifth day of July, in. the year of our Lord.
One thousand eight hundred and sixty-four, in the twenty-eighth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said John Henry Johnson, Her special license that I, the said John
Henry Johnson, my executors, administrators, and assigns, or such others
as I, the said John Henry Johnson, my executors, . administrators, or
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 Inven-
tion for "IMPROVEMENTS IN SAFETY VALVES," a communication to me from abroad
by Felix Ménard, of Paris, in the Empire of France, Engineer, upon the con..
dition (amongst others) that I, the said John Henry Johnson, my executors or
administrators, by an instrument in writing under my hand and seal, or
under the hand and seal of one of 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 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 John Henry Johnson, 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, reference being had to the accompanying Drawings, and to the
letters and figures marked thereon, that is to say:-
The said Invention relates to an improved construction and arrangement of
safety valve, suitable either for locomotive, stationary, or marine engine boilers
and for steam generators, or compressed air or gas containers of all kinds, and
consists in the employment in combination with a safety valve of the regulated
size, according to the heating surface of the boiler if applied to a steam gene-
rator of a small supplementary valve operating as herein-after described. The
main valve is entirely enclosed in a chamber, and is unconnected with any
other mechanism thus dispensing with levers, weights, and springs for holding
it down. The valve seat may consist of two concentric rings or bearing sur-
faces between which are formed the escape apertures for the steam, such
apertures leading downwards to the outside of the valve chamber. On one
side of this chamber there is a passage which leads from the upper part of the
chamber above the main valve into a second chamber situate on one side of
the first chamber in which second chamber works the small supplementary

page_text: valve herein-before referred to. An opening is made in the bottom of the
second chamber which communicates directly with the interior of the boiler and
through this opening passes the spindle or guide of the small valve, such
spindle or guide being cut away or grooved longitudinally to allow the steam to
pass by it when requisite. A portion at the lower end of this valve spindle is
not grooved or cut away, but is made to fit accurately inside the aperture
leading to the boiler so as to close the same when the small valve is elevated:
The small valve which is situate at the upper end of the spindle or guide above
'referred to is held down by the direct pressure of a fixed weight fitted thereto;
so long as the pressure in the boiler does not exceed the desired amount. the
small valve will remain closed and the steam will be free to pass through the
aperture in the bottom of the second chamber, thence into the second chamber
and along the passage which leads to the upper surface of the main safety
valve, and consequently that valve will be balanced by an equal pressure of
steam above and below; but should the pressure of the steam become unduly
elevated then the small valve will be lifted and will cause the lower aperture
leading into the boiler to be shut. The steam which had previously balanced
the main safety valve will now escape into the atmosphere by the small valve,
and as the lower aperture leading to the boiler is closed, the main safety valve,
being no longer balanced, will consequently be raised, and will allow the steam
to escape freely until the reduction in the pressure has permitted of the closing
of the small valve again, when the balance of pressure on the main valve will
be restored and the valve will return to its seat again. For the facility of
repairs it is proposed to tap the small valve seat into the second chamber so
that the valve and its seat may be readily removed and cleaned or repaired.
And in order that the said Invention may be fully understood I shall now
proceed more particularly to describe the same, and for, that purpose I shall
refer to the Figures on the annexed Sheet of Drawings, the same. letters of
reference indicating corresponding parts in both Figures...
:
Fig. 1 of the Drawings represents a vertical sectional elevation of the im-
proved safety apparatus, and Fig. 2 is a corresponding plan of the same, with
one half in horizontal section..
The steam from the boiler enters at A, through the openings or channels in
the stem of the small valve C, and fills the chamber B, thereby exerting its
pressure upon the upper surface of the main safety valve. D, which rests upon
two annular concentric valve seats or faces E, E', between which are situate
the escape apertures O. This main valve which is also guided by a cruciform
stem F receives on its under face the direct pressure of the steam; from the
boiler, and consequently it is balanced upon its seat by the upper and under

page_text: pressure exerted thereon. Should the steam pressure become unduly elevated
the small valve C will be raised and the solid part or plug G on the bottom of
the valve spindle will close the communication between the boiler and the
chamber B, and the steam which previously pressed down upon the valve D will
escape through the orifice at I, I, which is opened by the lifting of the small
valve or plug C. The pressure on the main valve being no longer balanced
it will be opened, and will allow the steam to escape direct from the boiler
through the escape apertures O, O. The small valve is represented as being
fitted inside a separate tube or seating F' which is tapped into the main cast-
ing of the chamber B, and may therefore be easily removed when required
for cleaning or repairs. The weight G₁ of the small valve may be applied as
shown directly to the valve itself without the intervention of a lever and for
convenience it may be made hollow, so as to contain mercury or other sub-
stance for weighting the same, or it may be otherwise constructed.
Having now described and particularly ascertained the nature of the said
Invention and the manner in which the same is or may be used or carried
into effect, I would observe in conclusion that what I consider to be novel
and original, and therefore claim as the Invention secured to me by the
herein-before in part recited Letters Patent is,-
First, the general construction and arrangement of safety apparatus for
steam generators, and for compressed air or gas reservoirs, substantially as
herein-before described and illustrated by the Drawings.
Second, the combination of a small weighted valve with a larger unweighted
valve upon which larger valve the steam, air, or gas pressure is balanced,
substantially in the manner and for the purpose herein-before described.
In witness whereof, I, the said John Henry Johnson, have hereunto set
my hand and seal, the Twenty-fourth day of January, One thousand
eight hundred and sixty-five.