IMPROVED MEANS FOR PREVENTING THE EXPLOSION OF KITCHEN AND OTHER DOMESTIC BOILERS
Year: 1881

page_text: LETTERS PATENT to Benjamin Giles, of Blackheath, in the County of Kent,
Hot Water and Sanitary Engineer, for an Invention of "IMPROVED MEANS
FOR PREVENTING THE EXPLOSION OF KITCHEN AND OTHER DOMESTIC
BOILERS."
PROVISIONAL SPECIFICATION left by the said Benjamin Giles at the Office
of the Commissioners of Patents on the 1st April 1881.
BENJAMIN GILES, of Blackheath, in the County of Kent, Hot Water and
Sanitary Engineer. "IMPROVED MEANS FOR PREVENTING THE EXPLOSION OF
KITCHEN AND OTHER DOMESTIC BOILERS."
The object of this Invention is to provide against the danger which arises from
the heating of kitchen and other domestic boilers when the water in the supply
and circulating pipes is frozen.
Attempts have already been made to provide for an efficient discharge of the
hot water from the boiler when the internal pressure due to the stoppage of the
circulating pipes exceeds the limit of safety, but these have ended in only partial
success.
I now propose to effect the discharge of the heated water from the boiler
immediately the internal pressure of the boiler has reached its determined limit
by providing for the rupture of a metallic covering to an opening made in the
boiler.
Into, say, the top of the boiler I fit a tube or collar, the inner end of which
communicates with the water space. The outer end of this tube or collar I close
by a metal cap piece of peculiar construction, and I render a portion of this metal
cover so brittle as to ensure its giving way, if not to a certain internal pressure of the
water alone by the addition to that pressure of a comparatively slight mechanical
impulse. The cap or cover I form by preference of thin sheet copper, which I make
concave on its upper face, and the edge of the metal I bend over to form a flange,
The
which I attach by brazing or solder to the outer end of the tube or collar.
cap or cover will thus present to the water a convex face, and it will be sufficiently
D
2743

page_text: stiff to resist the upward pressure of the water in the boiler until it rises to a
dangerous limit, say, for example, 50 lbs. to the inch.
Supposing the cover to be made so as to yield to this pressure the concave
portion of the cover will be thrust outwards, and loosing its concave form it will
suddenly assume, under the continued pressure of the water, a convex form, the
tendancy of which change will be to rupture the metal and provide an escape for
the boiling water.
In order to render this result the more certain I subject to hammering a portion
of the copper cap that will lie near its junction with the tube or collar and thus
impart a brittleness thereto which will facilitate the rupture of the metal at the
moment that the buckling of the cover under the pressure of the water takes
place.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Benjamin Giles in the Great Seal Patent Office on the 30th
September 1881.
BENJAMIN GILES, of Blackheath, in the County of Kent, Hot Water and
Sanitary Engineer. IMPROVED MEANS FOR PREVENTING THE EXPLOSION OF
KITCHEN AND OTHER DOMESTIC BOILERS."
The object of this Invention is to provide against the danger which arises from
the overheating of kitchen and other domestic boilers when the water in the supply
or other circulating pipes is frozen or the supply or circulating pipes are corroded.
Attempts have already been made to provide for an efficient discharge of the hot
water from the boiler when the internal pressure due to the stoppage of the
circulating pipes exceeds the limits of safety but with only partial success; I now
propose to effect the discharge of the heated water immediately the internal pressure
in the boiler has reached its determined limit by providing for the rupture of a
metallic covering to an opening made in the boiler.
In the accompanying Drawing Fig. 1 shews in front elevation a kitchen range
fitted with a safety or discharge vent according to my Invention, and Fig. 2 is a
cross section of the same taken on the line 1, 2, of Fig. 1.
In these Figures A is the boilers of the range, into the top of which is fitted a
short tube or collar B communicating with the water space; screwed into this tube
is an inverted hollow cone C which is closed by a metal cap piece or cover D of
peculiar construction, which it is intended shall resist a given pressure of steam
and give way under an excess of pressure in the boiler; this safety apparatus is
shewn in vertical section at full size at Fig. 3. A portion of the cap piece DI
render by hammering so brittle as to ensure it giving way, if not to a certain
internal pressure of the water alone by the addition to that pressure of a com-
paratively slight mechanical impulse. The cap piece D I make preferably of thin
sheet copper forming a concave on its upper face, as shewn at Fig. 3, and bending
over its edge so as to form a flange, which is attached by solder to the cone C.
The cap piece D will thus present a convex face to the water, and will be sufficiently
stiff to resist the upward pressure of the water in the boiler until it rises to a
dangerous height, say, for example, fifty pounds to the inch. Supposing the cap
piece D to be made so as to yield to this pressure, the moment that pressure is
reached, instead of continuing to present a convex face to the water the cap piece
will be thrust outwards, and since the metal is made brittle by hammering, the
buckling will rupture the cap piece and cause it to take a form somewhat like that
shewn in Fig. 4, thus providing an escape for the steam and water and thereby
preventing an explosion of the boiler.
In order to prevent the steam and water being discharged into the kitchen or
other apartment containing the boiler when a rupture of the cap piece takes place
the safety apparatus may be enclosed in a watertight metal box fitted with a pipe
leading to the outside of the building. This box is shewn at E as screwed to a
flange carried by the tube B, and into the top of the box the discharge pipe F is
screwed.
.
It will be understood that on removing the watertight box E from the tube B
the cap piece D can easily be renewed after it has been ruptured.
I would here remark that my safety apparatus may be adapted to yield to any
desired pressure by employing for the cover D sheet metal of any desired strength
of resistance. Thus instead of employing metal that will rupture at a pressure of
fifty pounds to the square inch, a thicker gauge may be used that will give way at a
pressure of sixty, eighty, or one hundred pounds to the square inch, as may be
desired.

page_text: Having now set forth the nature of my Invention of "Improved Means for
Preventing the Explosion of Kitchen and other Domestic Boilers," and explained
the manner of carrying the same into effect, I wish it to be understood that under
the above in part recited Letters Patent I claim,―
The means above described for ensuring the rupture of the cover which closes
the escape tube for the water from over-heated domestic boilers.
In witness whereof, I, the said Benjamin Giles, have hereunto set my hand
and seal, the Twenty seventh day of September, in the year of our Lord One
thousand eight hundred and eighty one.
D. GILES. (L.s.)