Belt drier B-72

The belt drier type B-72 was originally designed to replace traditional drum driers for loose fibres.
Later, with certain specific modifications, it was also used to process dyed acrylic tow, polypropylene and polyester tow, to carbonize wool in loose fibres after treatment in acidifying vats and to dry cotton-wool, ramie, rayon, etc.

The main features of the machine are:

• conveyor belt made of perforated stainless steel sheets or carbon steel sheets for wool in loose fibres. If cotton-wool has to be dried, a special textile mesh is used, specifically designed not to retain loose fibre
• ventilation by means of warm air is which is uniformly blown on the whole conveyor belt surface and symmetrically re-circulated in the lower part through two side channels. There is consequently a slight depression on the conveyor belt surface which ensures fibre stability on the belt in spite of the high ventilation
• uniform drying down to the required residual moisture rate
• High specific production output.

The drier can be heated with steam, diathermic oil or superheated water by means of steel-tube heat exchangers, tested to 40 bar pressure, or gas burners: it is equipped with large air filters of stainless steel filter mesh, which are readly accessible and removable for cleaning.

In order to ensure uniform residual moisture after drying, it is essential to feed the material uniformly onto the belt. Hence various feed mechanisms are used as follows:

• feeders for loose fibres are equipped with a belt with stainless steel pins, a distribution comb with special divice to adjust distance from the belt, al large diameter delivery roller to process long fibres and cleaning brushes.
  There are independent speed control units for the belt and the distribution comb
• for tow, single or multi-head plaiters are used, if necessary equipped with special compressed air (ALEA-patented) openers.

The first photo shows a steam-heated plant, comprising a B-72 with feeder for loose fibres equipped with opener and storage belt. The following photograph shows a 4-chamber machine with feeder for hydroextracted tow.

The pictures above show:
1.plant comprising a drier for loose fibres and a drier for hydroextracted tow, both steam heated
2.detail of the outlet of a B-72 with pick-up of dry tow, driven by a set of photocells.
3.detail of the distribution comb in a 4-chamber machine processing cotton-wool
4.detail of the delivery of dry cotton-wool on a conveyor belt.

Since the modular construction is one of the features of the B-72 (each unit is 3250 mm long), each drier can be arranged according to the required production output.
The machine is manufactured with belts of 5 different widths: 1300, 1600, 2000, 2500, and 3000 mm.

Cross section of a B-72: fans are mounted on the top of the machine, linked to the motor through a special self-cooling coupling. Side filters can readily be cleaned. Re-circulated air is filtered, drawn by fans and heated via burners or batteries.
Longitudinal section of a B-72 chamber: note the position of air heating batteries and the path of air which is uniformly conveyed onto the material to be dried. To ensure a uniform drying effect, air is blown from above downwards.
There are various design combinations as follows:
- a chamber equipped with feeder for hydroextracted loose fibres with storage belt
- two chambers for leviathan-washed wool. The intermediate feeder - without the storage belt - processes partly dried wool, thus avoiding any damage to the fibres
- a chamber equipped with opening device for hydroextracted loose fibres, pneumatic conveying system and feeder
- a chamber with feeder for tow, equipped with pneumatic opening and cooling devices (max. 12 opening devices).