STABILO: Knit processing dryer

The "Stabilo" name refers to the family of dryers arranged with twin conveyors, as opposed to the CA family based on single conveyor design.

Stabilo 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.

Useful 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.

 

One pass "STABILO" dryer equipped with tilting nozzles,
automatic air filter cleaning and gas burners.


One 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
  • after the first run it drops on the second run and so on up to the plaiter exit
  • stainless steel chutes make the drop between the passes airtight, for energy saving reasons

Maintenance 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.


"STABILO" with tenter feeding arrangement

ALEA 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 air.
Major points, aside from the hightech injected into the dryer from the standpoint of its air circuit and distribution features, are:

    • the "tumbling system" to get better softness as well as improved handle and lower residual shrink
    • the "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 with it
  • high evaporating capacity via our "edgeless" air diffusers and circular air ducts leading to the air nozzles
  • straight 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
  • inverter controlled drives to get the highest flexibility and econony of machine operation
  • inspection ports able to show to the machine operator the actual set-up of the fabric under process
  • differential ventilation for face and back fabric
  • exhaust air ducts in each bay for a precise balance of the make-up air
  • "Retrasystem" option exit in lieu of the standard relax conveyor
  • very easy set-up of the dryer which comes in pre-assembled units from our manufacturing facility

Two pass "STABILO" dryer, also available with entry/exit on opposite sides

Features

1. Entry side
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.

2. Conveyors
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 maintainance.

3. Blowing system
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.

4. Tumbling nozzles
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 handle

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 be done.
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.

6. Exit side
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.

7. Retrasystem (TM)
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
STABILO Relax dryers