IMPROVED APPARATUS TO BE APPLIED TO KITCHEN OR OTHER BOILERS TO PREVENT EXPLOSIONS."
Year: 1881

page_text: LETTERS PATENT to John Tattersall, of Manchester, in the County of
Lancaster, for an Invention of "IMPROVED APPARATUS TO BE APPLIED TO
KITCHEN OR OTHER BOILERS TO PREVENT EXPLOSIONS."
PROVISIONAL SPECIFICATION left by the said John Tattersall at the Office
of the Commissioners of Patents on the 21st February 1881.
JOHN TATTERSALL, of Manchester, in the County of Lancaster. " IMPROVED
APPARATUS TO BE APPLIED TO KITCHEN OR OTHER BOILERS TO PREVENT
EXPLOSIONS."
This Invention consists of a simple and convenient form of safety apparatus to
be applied to kitchen or other boilers to prevent their explosion in the event of the
freezing of the water in the circulation pipes, or whenever from any cause whatever
there is a dangerous amount of pressure of steam in the boiler. In the top of the
boiler (or other convenient part) I fix, preferably by screwing, a short pipe, say,
of about one inch internal diameter, and about two or three inches long (more or
less).
The upper (or outer) end of this pipe is formed with a screw thread on the
outside, over which fits a screwed cap.
A hole is formed through the centre of the cap corresponding with the bore of
the short pipe, and when the cap is screwed on, this hole is closed by means of a
disc of lead or other suitable metal or alloy (about the same diameter as the outside
of the pipe), which is placed over the top of the pipe and held in position by
screwing the cap tight, so as to make a steam tight joint.
This disc of lead or other metal or alloy must be of such a strength as to resist
the ordinary working pressure of the boiler, but upon the pressure of the steam
increasing to a dangerous degree, the disc gives way and allows the steam to escape,
and thus explosion of the boiler or pipes is prevented.
This form of safety apparatus is readily renewed by placing a fresh disc of lead
or other metal or alloy in the inside of the screw cap.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Tattersall in the Great Seal Patent Office on the 20th
June 1881.
JOHN TATTERSALL, of Manchester, in the County of Lancaster. " IMPROVED
APPARATUS TO BE APPLIED TO KITCHEN OR OTHER BOILERS TO PREVENT
EXPLOSIONS,"
This Invention consists of a simple and convenient form of safety apparatus to
be apparatus to be applied to kitchen or other boilers to prevent their explosion in
the event of the freezing of the water in the circulation pipes, or when from any
cause whatever there is a dangerous amount of pressure of steam or air in the
boiler.
The same apparatus is also equally applicable for the prevention of the collapse
of hot water or steam drying cylinders by external atmospheric pressure, whenever
a partial vacuum is formed therein by condensation or otherwise.
The principal feature of this Invention is the formation of a weak point in the
kitchen or other boiler, by means of a disc or plate of copper, lead, tin, zinc, brass,
or other alloys, talc, mica, prepared paper, textile fabric, india rubber, asbestos, or
any other suitable material weaker than the boiler itself, and of such a nature that
any dangerous pressure will cause it to tear or give way (and thus release the
steam) at a much lower pressure than would be required to explode the boiler.
Such being the nature and object of my said Invention, I will now proceed to
describe more in detail the manner in which the same is to be or may be performed
or carried into practical effect, and in order that the same may be clearly under-
stood I have hereunto annexed a Sheet of Drawings illustrative thereof, and have
marked the same with figures and letters of reference, corresponding with those in
the following explanation thereof.
Fig. 1 in the annexed Drawing is an elevation, Fig. 2 a plan view, and Fig. 3 a
vertical section of my improved safety apparatus.
In the top of the boiler (or other convenient part) I fix, preferably by screwing,
a short pipe or socket a, a, say of about one inch internal diameter, and about two
to three inches long (more or less).
The upper (or outer) end of this pipe or socket is formed with a screw thread on
the outside, over which fits a screwed cap b, b.
A hole C, C,
is formed through the centre of the cap corresponding with the bore
of the short pipe a, a, and when the cap b, b, is screwed on this hole is closed by
means of a disc or plate d, d; of lead or other suitable metal or material (about the
same diameter as the outside of the pipe), which is placed over the top of the pipe
a, a, and held in position by screwing the cap b, b, tight, so as to make a steam
tight joint; or a split ring of india rubber may be used, into which the disc is
placed, so as to form a steam tight joint.
This disc or plate of copper, lead, or other metal or material must be of such a
strength as to resist the ordinary working pressure of the boiler, but upon the
pressure of the steam increasing to a dangerous degree the disc or plate gives way,
and allows the steam to escape, and thus explosion of the boiler or pipes is
prevented.
This form of safety apparatus is readily renewed by placing a fresh disc or plate
d, d, of copper or other metal or material in the inside of the screw cap b, b.
Figs. 4, 5, and 6 are similar views of a modification of the above, wherein the
tube a, a, is made shorter, and the cap b, b, instead of having its sides squared like
a nut, is provided with a guard e, e, which prevents the hole c, c, from becoming
closed by a piece of brick or other material accidentally lodging over it, and at the
same time forms a handle by means of which it can be unscrewed by a simple piece

page_text: of iron without the use of a screw key; or a wire netting or grid may be placed
over the hole to prevent the disc being injured by any falling material.
Having now described the nature and object of my said Invention, together
with the manner in which the same is to be or may be performed or carried into
practical effect, I wish it to be understood that I claim as my Invention the peculiar
construction of safety apparatus for kitchen or other boilers, as hereinbefore
described and illustrated by the annexed Drawings, or any mere imitation or modi-
fication thereof, constructed and operating in substantially the same or a similar
manner.
In witness whereof, I, the said John Tattersall, have hereunto set my hand
and seal, this Fifteenth day of June, in the year of our Lord One
thousand eight hundred and eighty one.
JOHN TATTERSALL. (L.S.)