Page 34 - 2010-2022 hose manufactureing ability and guide

YARNS Yarn size is normally designated using the
Yarns are used in hose for reinforcement of denier system (weight in grams of 9000 meters of yarn).
the tube material to provide the strength to The TEX system (the weight in grams of 1000
achieve the desired resistance to internal meters of yarn) is also widely used. Both are
pressure or to provide resistance to collapse, or direct yarn measurements, i.e., as the number
both. The basic yarn properties required for increases, the yarn size increases.
hose reinforcement are: adequate strength, WIRES
acceptable heat resistance, dynamic fatigue Reinforcing wire is used in a wide variety of
resistance, and satisfactory processability for the hydraulic and industrial hose, primarily where
various methods of reinforcing hose. Other textiles alone do not satisfy the special
special properties such as stiffness, adhesion, engineering requirements or the service
conductivity, etc., may be developed depending conditions for which the hose is designed.
upon the specific hose application. Yarn is
available in two basic forms: staple (sometimes Steel Wire
referred to as spun yarn) and filament. Steel wire has strength, high modulus for
Staple dimensional stability, fatigue resistance, and
low cost, and is the major reinforcement used in
Staple yarn is made by twisting bundles of
short fibers to form a continuous yarn. The high pressure hose and in most suction hose.
staple obtains its strength from the binding Steel Wire (High Tensile Low Carbon)
effect of the twist imparted to the individual Small diameter high tensile steel wire is most
fibers. The base staple yarn is called a singles. commonly used for reinforcement in braided or
It is made from fiber bundles twisted together in spiral-wound hose for high pressures and high
one direction to form a singles strand. If two or temperature applications. The wire normally
more single yarns are twisted together, usually used ranges in size from 0.008 inch to 0.037
in a direction opposite that of the singles yarn, inch (0.20 mm to 0.94 mm) in diameter.
the result is a plied yarn. Two or more plied Flat Wire Braid
yarns may be twisted to form a cable cord. The
strength, elongation, and thickness of yarn are a This consists of an odd number of steel wires
function of the twist level and the number of interwoven to produce a flexible reinforcement.
fibers in the bundle. Staple yarns may be made It is used in specialized types of hose, either by
from natural or synthetic fibers or a blend of the itself, or in combinations with other shapes of
two. The cotton count system is normally used steel wire. Flat braids of standard sizes are
to designate staple yarn size. The number of composed of 9, 13, 17 or 21 strands of wire in
“hanks” in one pound is the yarn number. A an “over two, under two” plain braid pattern.
cotton hank is 840 yards. Therefore, a 2’s staple Wire Cable
yarn contains approximately 1680 yards in one Wire cable consists of multiple strands of
pound. The cotton count system is an inverse round wire. It provides high bursting strength
measure of the linear density of the yarn, i.e., as without undue loss of flexibility or crush
the yarn number increases the yarn size is resistance. Sizes range from 0.047 inch to 0.25
decreased. inch (1.19 mm to 6.4 mm) in diameter and are
Filament Yarns made from high tensile carbon steel wire.

Filament yarn is produced by extruding Round Wire
synthetic material through a spinnerette Round is the most commonly used wire
containing hundreds of orifices. The mono- shape in hose fabrication. It ranges in size from
filaments from each of the orifices are brought 0.031 inch to 0.875 inch (0.79 mm to 22.2 mm)
together to form a multifilament yarn. in diameter. Round wire is generally made of
Filament yarns have higher tenacity (strength high tensile carbon steel.
per unit of weight — grams per denier), in the Rectangular Wire
range of 2 to 3 times that of staple yarn on the
same material type and size. Rectangular wire is most commonly used as a
helical reinforcement on the interior of rough
bore suction hoses to prevent collapse. It is
sometimes used in the body of the hose.

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