MODE OF OPERATION
- CLASSIFICATION - Some of the operating devices in blow room machines function only for opening.Most of them work, however, in cooperation with cleaning apparatus such as grids, etc., and thereby function also as cleaning units. Consequently, they are designed to operate both in opening and cleaning machines.
OPENING UNITS CAN BE CLASSIFIED AS:
- endless path;
- gripping devices;
- rotating assemblies.
1. ENDLESS PATH
Spiked lattices (Fig. 13) serve as forwarding and opening devices in bale openers and hopper feeders. They consist of circulating, endless lattices or belts with transverse bars at short intervals. The bars are of wood or aluminum; steel spikes are set into the bars at an angle and at greater or lesser spacings.
Owing to their configuration, inclined lattices usually feed the material upward at an angle. The spikes penetrating into the raw material carry the material along. Opening occurs because the spikes drag small tufts out of the large infeed material when passing the latter, and because in the upper region of the lattice there is a counter-rotating roller (Fig. 14), also clothed with spikes and located fairly close to the lattice. This roller strips the large material lumps from the lattice. The counter-operation of the two systems of spikes causes the tufts to be plucked apart. THE INTENSITY OF THE OPENING ACTION IS DEPENDENT UPON:
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Fig. – Spiked lattice
Fig– Securing band (a / b), bars and spikes of the inclined lattice
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2. GRIPPING ELEMENTS (PLUCKING SPRINGS)
Fig. – Plucking spring
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Some manufacturers, for example former Schubert & Salzer and Trützschler, have used plucking springs for opening. Two spring systems, facing each other like the jaws of a pair of tongs, are parted and dropped into the feed material and are then closed before being lifted clear. They grasp the material like fingers. This type of gripping is the most gentle of all methods of opening, but it produces mostly large to very large clumps of uneven size. This type of opening device is therefore no longer used.
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3. ROLLERS WITH TEETH (BLADES) OR SPIKES
Flat, oval or round bars are welded, riveted or screwed to closed cylinders. In another system flat bars are secured with the narrow side facing in the direction of rotation.
The rollers are therefore called spiked rollers (Fig. 16). Various spacings of the striker elements are used. These devices are incorporated mainly in modern horizontal cleaners, chute feeds, mixing bale openers, step cleaners, etc., which are located from the start to the middle of the blowroom line. At the start of the line, the spacing of the striker elements on the roller is greater; finer spacings are used in the middle (to the end) of the line. The rollers rotate at speeds in the range of 600 - 1 000 rpm. |
Fig. – Spiked roller
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