CRUSH RESISTANT HOSE

TUYAU SOUPLE RESISTANT A L'ECRASEMENT

English Abstract

Abstract
Novel industrial tubing comprising at least one
helix of a polyolefin integral with the tubing wall to
produce a crush-resistant tubing. In particular a crush-
resistant vulcanised rubber tubing is provided which has
formed integral with the wall thereof at least one helix
of "tuffclad".

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A crush-resistant tubing comprising a wall formed from vulcanized
rubber and a wall reinforcement completely embedded in and integrally bonded
to said rubber formed from a non-overlapping helix having axially spaced turns
of ultra high molecular weight polyethylene of 0.94 g/cm3 specific gravity.
2. A crush-resistant tubing comprising a wall formed from vulcanized
rubber and a wall reinforcement completely embedded in and integrally bonded
to said rubber formed from a non-overlapping helix having axially spaced turns
of polyethylene having a molecular weight of from 4 to 4.5 million as measured
by the light diffusion method and having a specific gravity of 0.94 g/cm3.

Description

s
The present invention relates to crush-resistant tubing and in
particular crush-resistant rubber hoses.
Throughout the specification the term "crush-resistant tubing or
hose" will be defined as tubing or hose which can be crushed flat by some
heavy weight and will substantially return to its original shape without any
significant weakening of the properties of the tubing or hose.
In heavy industry it is often nècessary to use large diameter hoses,
to carry slurry, water or other such materials. These hoses were convention-
ally made from rubber with wire reinforcing. Unfortunately when a section of
these hoses are flattened, it is necessary to use physical force, such as
hammering to return the hose substantially to its original shape. Unfortu-
nately the wire reinforcing undergoes cold working during the crushing and
the subsequent hammering. The wire usually breaks at the area of cold working
and the tubing becomes delaminated from the wire thus, ultimately the hose
fails after only a few crushings and reshapings.
The present invention overcomes this problem by providing a crush-
resistant tubing.
According to the present invention there is provided a crush-
resistant tubing comprising a wall formed from vulcanized rubber and a wall
2~ reinforcement completely embedded in and integrally bonded to said rubber
formed from a non-overlapping helix having axially spaced turns of ultra
high molecular weight polyethylene of 0.94 g/cm specific gravity.
~ ne suitable ultra high molecular weight polyethylene having the
Registered Trademark "Tuffclad" has a molecular weight of 4 to 4.5 million
as measured by the light diffusion method. It is made of extremely long
nearly branch free molecular chains. The properties of "Tuffclad" are as
follows:-
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As "Tuffclad" has self-lubricating and high-slip
properties its suitability for strengthening tubing was
unsuspected. However, during experimentation it was surpris-
ingly found that a strip of "Tuffclad" was bonded into the
wall of a rubber hose during the normal vulcanising step and
forming a strong bond between the rubber and the "Tuffclad",
such that the rubber hose exhibits "crush-resistant"
properties. The resulting bond is such that during reported
deformation tests there appeared to be no separation between
the "Tuffclad" and the rubber.
In a typical vulcanising process the high density
polyethylene is wrapped in its appropriate configuration
in the tubing wall and the thus layered uncured tubing placed
in an autoclave to cure for 6 - 8 hours at a temperature of
about 500 F.
The polymeric material can be wrapped in the rubber
wall in an configuration necessary to strengthen the hose,
for example double helixes, single helixes, a complete layer.
In using double helixes each separate helix can be
positioned such that the two helixes run in with no overlap-
ping or run overlapping each other. The thickness width and
spacing of the polymeric material will depend on the size
and strength requirements of the tubing.
To provide an abrasive resistant lining as well as
a crush resistant hose the inner layer of the hose can be
formed of overlapping layers of "Tuffclad" which are wound on
a mandril with the composite rubber hosing and core built on
top of the thus coated mandril and the tubing then vulcanised.
The thus formed tubing provides an improvement over
existing piping such as steel in that previously problems arose
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in providing a layer of "Tuffclad" which would bond because
of the differential between the expansion properties of
"Tuffclad" and previously used pipe walls.
The end of each tubing can have a flange of
"Tuffclad" projecting outwardly therefrom such that in
joining tubing together the "Tuffclad" flanges are
positioned -together and a flange of suitable material is
clamped on each side of the mating "Tuffclad" flanges by
any convenient means, such as bolting, to form a leakproof
joint between the tubing.
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