A. METHOD OF CONSTRUCTING LEAD OR OTHER DUCTILE OR ELASTIC METAL PIPES FOR USE AS WATER SERVICES."
Year: 1881

page_text: LETTERS PATENT to John Samuel Rigby, of Farnworth, in Widnes, and
JOHN MANGNALL, of Manchester, both in the County of Lancaster, for an
Invention of "A. METHOD OF CONSTRUCTING LEAD OR OTHER DUCTILE OR
ELASTIC METAL PIPES FOR USE AS WATER SERVICES."
PROVISIONAL SPECIFICATION left by the said John Samuel Rigby and
John Mangnall at the Office of the Commissioners of Patents on the
31st March 1881.
JOHN SAMUEL RIGBY, of Farnworth, in Widnes, and JOHN MANGNALL, of
Manchester, both in the County of Lancaster. "A METHOD OF CONSTRUCTING
LEAD OR OTHER DUCTILE OR ELASTIC METAL PIPES FOR USE AS WATER
SERVICES."
The piping is made sectionally of an oval or other shape, so far departing from
the circle that the area enclosed by its perimeter or girth shall not be more than.
eleven-twelvths of the area which would be enclosed if the same perimeter were
the circumference of a circle, and also of such a strength that it will bear the
ordinary pressure of the mains without altering its shape; in order to secure this
shape in the largest sizes, a midfeather connects the flat sides in the direction
of the minor axis of the oval, and gives it sectionally the shape of a link in a cable
chain.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Samuel Rigby and John Mangnall in the Great Seal
Patent Office on the 29th September 1881.
JOHN SAMUEL RIGBY, of Farnworth, in Widnes, and JOHN MANGNALL, of 27,
Smedley Road, Manchester, both of the County of Lancaster. "A METHOD OF
CONSTRUCTING LEAD OR OTHER DUCTILE OR ELASTIC METAL PIPES FOR USE AS
WATER SERVICES."
Our Invention relates to the construction of lead or other soft ductile or elastic
metal piping for use as water services, and with a view to considerably diminish
their liability to burst through frost.

page_text: The piping is made cross sectionally of a shape so far departing from the circle
that the area enclosed by its perimeter or girth shall not be more than eleven
twelfths of the area which would be enclosed if the same perimeter or girth was
the circumference of a circle, and also of such a strength that it will bear the
ordinary pressure in the mains without altering its shape; in order to secure the
shape in the larger sizes of piping made from very soft metal, as lead, and also to
avoid making such piping of great strength, a midfeather of metal connects the
flat sides in the direction of the shortest axis, such midfeather being made only
sufficiently strong to retain the shape of the piping under ordinary pressures and
strains. Practically we recommend the piping to be constructed with an area of
bore, bearing such a relation to its girth, to be twenty or more per cent. less than
the area of bore of a round pipe with a girth of equal magnitude, and also prefer
the elliptical or some simple curvilinear shape approaching thereto sectionally,
as ordinary round piping can be readily converted into such shapes by pressure
externally.
When water confined in piping thus constructed freezes, the expansion
consequent thereto developes an hydraulic force, which acting equally in all
directions tends to force the shape more circular; this alteration of shape necessarily
increases the area of the piping and the extra space required for the water in its
frozen condition is thus provided.
It is obvious that the material substance of the piping must be only those metals
or substances admitting of a considerable amount of displacement amongst its
individual molecules without materially affecting their cohesive strength, such as
lead or copper, and which are usually called soft, malleable, ductile, or elastic.
In adapting this principle of construction to malleable iron, copper, brass, and
other piping, it is necessary that the piping shall be made homogeneous in strength
throughout its periphery, and that that known as "solid drawn" is most reliable.
But welded, soldered, or brazed piping will generally be found defective, and it is
further recommended to construct the piping generally, only moderately, stronger
than is necessary to retain its primitive shape under ordinary circumstances, it
being thus more susceptible to compensate for the frost action.
Having now explained the nature of our Invention, and the manner the same is
to be performed, we hereby declare that we claim the construction and adaption
of piping made of soft, ductile, malleable, or elastic metal or material for use as
water services made transverse sectionally of such shapes as employ perimeters,
which enclose areas not more than eleven twelvths of the area of a circle employing
a perimeter of equal magnitude.
In witness whereof, I, the said John Mangnall, on behalf of myself and the
said John Samuel Rigby, have hereunto set my hand and seal, this Twenty
seventh day of September, in the year of our Lord One thousand eight
hundred and eighty one.
Witness,
WILLIAM TURNER.
JOHN MANGNALL. (L.S.)