IMPROVEMENTS IN SAFETY VALVES
Year: 1860

page_text: LETTERS PATENT to John Harvey, of Circus Street, Marylebone Road,
Bath and Hot Water Apparatus Manufacturer, for the Invention of
"IMPROVEMENTS IN SAFETY VALVES."
Sealed the 7th August 1860, and dated the 21st April 1860.
PROVISIONAL SPECIFICATION left by the said John Harvey at the
Office of the Commissioners of Patents, with his Petition, on the 21st
April 1860.
I, JOHN HARVEY, of Circus Street, Marylebone Road, Bath and Hot
Water Apparatus Manufacturer, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN SAFETY VALVES," to be as follows:-
This Invention relates to a peculiar construction and arrangement of safety
valve for bath and hot water heating apparatus, which is also applicable to steam
generators. According to this Invention, it is proposed to apply to the boiler
of any ordinary hot water apparatus a pipe, provided at its upper end with a
perforated gun metal cap and socket, into which socket is screwed an ordinary
fusible metal plug, so as to hermetically close the pipe. In the event of the
free circulation in the pipes becoming stopped by any cause, the stean
generated in the boiler will, by increasing the temperature of the air confined in
the safety valve pipe, effect the fusion of the metal plug, and thereby afford a

page_text: free vent or escape for the steam and water from the apparatus, and so prevent
explosions. When applied to ordinary steam generators, the safety valve pipe
is to be fitted to the boiler at any convenient part thereof below the water line.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Harvey in the Great Seal Patent Office on the
10th October 1860.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HARVEY, of Circus Street, Marylebone Road, Bath and Hot Water Apparatus
Manufacturer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-first day of April, in the year of our
Lord One thousand eight hundred and sixty, in the twenty-third year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said John Harvey, Her special license that I, the said John Harvey,
my executors, administrators, and assigns, or such others as I, the said John
Harvey, 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 Invention for "IMPROVEMENTS IN
SAFETY VALVES," upon the condition (amongst others) that 1, the said John
Harvey, by an instrument in writing under my hand and seal, should par-
ticularly 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 Harvey, 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, reference being had to the accompanying Drawings, and to tho
letters and figures marked thereon, that is to say :-
My said Invention relates to a peculiar construction and arrangement of
safety apparatus for bath and hot water heating apparatus, which is also
applicable to steam generators. According to this Invention, it is proposed to
apply to the boiler of any ordinary hot water apparatus a pipe provided with

page_text: a perforated gun metal cap and socket, into which socket is fitted an ordinary
fusible metal plug so as to close the pipe hermetically. In the event of the
free circulation in the pipes becoming stopped by any cause, the steam
generated in the boiler will, by increasing the temperature of the air confined
in the safety pipe, effect the fusion of the metal plug, and thereby afford a
free vent or escape for the steam and water from the apparatus, and so
prevent explosions. When applied to ordinary steam generators, the safety
pipe should be fitted to the boiler at any convenient part thereof below the
water line, or if fitted to the top of the boiler, it should be extended down-
wards internally, so as to dip below the surface of the water therein.
And in order that my 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 several Figures on the Sheet of Drawings berennto annexed,
the same letters of reference indicating corresponding parts in both Figures.
Figure 1 of the annexed Sheet of Drawings represents my improved safety
apparatus as applied to the boiler of an ordinary hot water heating apparatus.
A is the body of the boiler, which is always kept full of water, and B is a
gun metal socket screwed into or otherwise secured to the upper part of the
boiler. To this socket is screwed the safety pipe C, into the bottom of which
is fitted the conical safety fusible plug D; this plug is held up to its seat by
a long bolt E and nut F. G is a perforated cap, screwed or otherwise
attached to the top of the pipe C, and over this cap is fitted a hood H for the
purpose of preventing the dangerous spreading of the steam and hot water on
the escape of the same. 1 is a dip pipe leading from the socket B to the
bottom of the boiler, and serving not only to aid the free circulation of the
water in the boiler itself from the top to the bottom, but also as a conductor
of heat to the socket containing the fusible plug. In the case of an accidental
obstruction occurring in the ordinary circulating pipes, which would convert
the boiler into a closed vessel, and so raise the temperature of the water to a
dangerous extent, the air which is contained within the space a between
the surface of the water and the fusible plug will become sufficiently heated to
melt the plug, and allow of the free escape of the steam from the boiler.
Figure 2 represents a sectional elevation of this apparatus as applied to a
steam boiler or generator. In this the overheating of the water will cause
the fusible plug D to melt, and so allow the steam to escape up the safety
pipe and out by the slots made in the cap on the top thereof.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried

page_text: 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 the general construction and
arrangement of safety apparatus for preventing the explosion of boilers and
other vessels in which water is heated, as herein-before described.
In witness whereof, I, the said John Harvey, have hereunto set my
hand and seal, this Twenty-seventh day of September, One thousand
eight hundred and sixty.
JOHN HARVEY. (L.S.)