Knit processing dryer
"Stabilo" name refers to the family of dryers arranged
with twin conveyors, as opposed to the CA family based on
single conveyor design.
dryers are arranged in one, two and three pass configuration,
depending on production output and preferred lay-out, as well
as up to a maximum of four drying bays.
There is also one special version with 3 pass:1 with ventilation
and 2 without ventilation but still in the chambers.
widths start from 1.20 m up to 3.4 m with heating source being
steam, thermal oil, gas and electrical batteries. The
design of this family is based on the "sandwich drying
technology" whereby the fabric is carried between two
belts that move at the same speed, within the drying compartments:
considering that fabric is fed between the conveyor in an
overfed fashion, it will dry and freely shrink in width and
length in tensionless conditions, thus reaching the highest
possible dimensional stability.
One more feature of the dryer design is to assign a quite
large fabric content under process, in the effort of giving
enough dwell time for the complete shrink to take place.
In this dryer special attention has been given to the design
of air nozzles and, in general to the ventilation circuit
which carries a very remarkable feature: air fans, being driven
by inverters, make possible to select the best appropriate
air flow (but also air speed and impact air) for the fabric
style so that range between 60% and 110% of the nominal air
flow (but also air speed and impact air) is available without
making recourse to mechanical adjustment of air nozzles.
pass "STABILO" dryer equipped with tilting nozzles,
air filter cleaning and gas burners.
more important feature refers to the tilting of the upper
air nozzles, at a frequency proportional to the fabric speed,
with the aim of increasing the shrinking capacity of the
fabric under process.
The drying process is very straightforward:
threading of the machine doesn't require major efforts
as it comes naturally once the first end is thrown onto
the feed conveyor at the entry: fabric climbs up to
the first conveyor and enters the dryer
the first run it drops on the second run and so on up
to the plaiter exit
steel chutes make the drop between the passes airtight,
for energy saving reasons
and cleaning of the dryer are also made easy because of
the large doors that give access to the lower area of
the machine where fans and heating systems are located.
Air filters are mounted on the side of the dryer, opposite
to the fans, and are accessible from the outside: they
are twin type, pull-out design, stainless steel meshing
for to withstand the corrosion coming from various chemicals
put on the fabric.
with tenter feeding arrangement
has in current production two families of dryers for knit
and woven fabric, respectively the "CA" and the
"Duplex" series. Last born of the Duplex family
is the single pass two belt "STABILO" dryer, whose
design and performances show that no efforts have been spared
for to come up with an extremely good use of the technological
Major points, aside from the hightech injected into the
dryer from the standpoint of its air circuit and distribution
"tumbling system" to get better softness
as well as improved handle and lower residual shrink
"Retrasystem", that's to say a simplified
compacting unit for operation on either tubulars or
open width at the same speed of the dryer and on line
evaporating capacity via our "edgeless" air
diffusers and circular air ducts leading to the air
vertical distribution of the air flow onto the fabric
and modular air fans, depending on dryer width, able
to maintain high production outputs on heavy styles.
On request, fans can be driven by inverters (variable
flow) for special operation
controlled drives to get the highest flexibility and
econony of machine operation
ports able to show to the machine operator the actual
set-up of the fabric under process
ventilation for face and back fabric
air ducts in each bay for a precise balance of the make-up
"Retrasystem" option exit in lieu of the standard
easy set-up of the dryer which comes in pre-assembled
units from our manufacturing facility
pass "STABILO" dryer, also available with entry/exit
on opposite sides
Fabric is taken to the spreading roll and to the inverter driven
overfeed roll. This whole, which also included the conveyor
rolls and relevant track control systems, is mounted as a preassembled
unit to be joined to the dryer's body.
These are made of teflon coated fiberglass filaments and are
driven by inverters, controlled via the speed potentiometer
mounted on the operator panel. It is of course available, on
option, the automatic speed control based on exit moisture reading.
The control of both the tension and the tracking of the two
belts is accomplished via high quality and very reliable equipments,
all these mounted on the entry plates for easy inspection and
This is the heart of the dryer and the part of it that carries
the most result of our efforts in the area of the aerodynamics
(round ducts "pipe and slide" system and air diffusers
made to offer minimum air resistance). Process air is taken
through an edgeless high efficiency air divider to the air
nozzles equipped with a special design air verticalizers.
Nozzles are offset in order to allow for the fabric to wave
and also for to maximize both the deep and superficial heat
exchange. Return air flow is laminar so to avoid any tracking
problem on the fabric. The "pipe and slide" nozzle
system makes cleaning operation very easy and remarkably fast.
These are installed inside the heating chamber and consist
of a numer of tilting nozzles able to upset the fabric wave
which gets done and redone at regular intervals and at a frequency
proportional to the dryer speed.The result is an important
increase of the shrink inside the dryer along with an improved
5. Air filtration
STABILO is normally equipped with twin manual pull-out type
air filters, equipped with the "check-test" facility,
able to indicate to the dryer operator that de-clogging should
Automatic cleaning of air filters is available on option,
the system being made of a s.s. mesh, kept in slow motion
and travelling before a vacuum nozzle that removes the lint
and takes it away to dust collecting bags.
Processed fabric drops onto the delivery conveyor, made of
anodized aluminium alloy square pipes mounted on chains.
This conveyor allows for cooling down of the fabric and does
not apply any stretch to the knit.
Such an arrangement also makes dryer threading very easy and
from a set-up point of view, like for the entry side, this
whole unit comes preassembled from our manufacturing facility.
This is an absolute news in the finishing which allows for
knit compacting on line with the dryer.
The unit can process open knit and tubulars side by side,
as they exit the dryer heating bay, and replaces the standard
"Relax" conveyor exit. It can be also by-passed
in all cases where compacting is not required. The compacting
chamber is heated by recovered air from the exhaust.
STABILO Relax dryers