Page 44 - 2010-2022 hose manufactureing ability and guide

Knit Reinforcement Wrap Reinforcement
Wrap reinforcement is applied spirally to
Rotary knitting machines used for hose rigid mandrel hose tube in multiple plies with
reinforcement were first developed in the early the direction of lay reversed with each
1900’s. Today their use has declined succeeding ply. The most common fabric
significantly in favor of textile spiral, but are reinforcement is tire cord, which has strength
still the common method for reinforcing radiator only in the cord direction. To compensate for its
hose because of its good torsional and uni-directional strength, plies are usually
circumferential flexibility needed for curved applied in multiples of two. This may be done
hose products. by rotating the mandrel or rotating the
Knitting can be horizontal or vertical with reinforcement around the mandrel as described
textile only. The yarn is fed from cone packages previously in the “Three Basic Methods of
(usually 4 or 8) through a series of eyelets Making Hose”. Wrapping is generally done
through latch-type needles onto the hose. with rubberized fabric thereby resulting in hoses
Although the knitted hose is easily shapeable in the lower working pressure range. However
for coolant hose applications, it is a very for large diameter hoses, generally above 4", it's
inefficient reinforcing method restricted to low the only available technique. Figure 2-14 shows
pressure applications. Figure 2-13 shows an 8- the wrap reinforcement being applied to a rigid
feed vertical knitter. mandrel hose.
When needed to prevent collapse or
kinking, a wire or thermoplastic helix or helixes
are added to the wrapped construction. These
can be a wide variety of thicknesses, usually
applied at a fairly high helix angle to oppose
inward and outward radial stress, but which do
not add significantly to the hose strength in the
axial direction.

Figure 2-14

Figure 2-13

RMA/IP-2/2003 23