An Improvement in Water Service Pipes to Prevent Fracture by Frost.
Year: 1897

page_text: Date of Application, 22nd Feb., 1897-Accepted, 17th Apr., 1897
COMPLETE SPECIFICATION.
An Improvement in Water Service Pipes to Prevent Fracture
by Frost.
I, ARTHUR EDWARD WRIGHT, of 114 Anderton Road, Sparkbrook, in the City of
Birmingham, do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and by
the following statement :—
My invention refers to water service pipes of lead, metallic alloys, or composition,
such as are used in dwelling houses and other places where they may be exposed to
the action of frost; and consists of a pipe which is longitudinally corrugated along
its entire length and in which the thickness of the material of the corrugations is
varied in such a manner as to offer an uniform resistance to internal pressure.
It is known that when the water contained in a pipe freezes, it, at the moment of
congelation, exerts a pressure upon all parts of the internal surface of the pipe; and
that this pressure acts perpendicularly to the surface at every point. The result of
this pressure upon the internal corrugations is such as tends to laterally compress
the material along the ridge of the corrugations. Upon the external corrugations
it exerts a lateral tensile stress which tends to produce a fracture along the ridge
of the corrugations.
To obviate this tendency to fracture along the ridge of the external corrugations,
I allow a greater thickness of material to the walls of the external than to those of
the internal corrugations; in accordance with the understood principle that a greater
mass of metal is required to resist a tensile than a compressive stress. The relativo
thickness of the material of the external and internal corrugations respectively, is
made approximately such that an internal pressure which would stretch the material
of the former would be sufficient to compress the material of the latter.
By which means, I claim to relieve the lateral tensile stress upon the external
corrugations; and that by such a distribution of the material of the wall of the pipe,
its sectional area may, at the moment of the congelation of the contained water, be
increased by a small straightening out of the corrugation rendering it more circular
in section; and without any tensile strain upon the material such as might cause a
fracture.
In the accompanying drawing I represent by a section view the disposition of the
metal in a water service pipe constructed in accordance with my invention.
I preferably make the depressed or concave parts as A as segments of a greater
circle than the elevated or convex portions B, in order to diminish the danger of
distortion of the tube when it is bent at a sharp angle.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is ;-
An improved pipe of lead or other material substantially as and for the purposes
described.
tary 1897.
MARKS & CLERK,
18 Southampton Buildings, London, W.C., and
13 Temple Street, Birmingham,
Agents for the Applicant.