Batch bleaching process machineries

Raw stocks and yams in packages or in beams can be bleached only by the liquor circulating machines. Cotton yam in the form of hank can be bleached as a rope of cloth using pressure kiers, washing machines and hypochlorite bleaching pits. But the modem tendency is to bleach in a more efficient manner in dyeing machines in the form of beams (Fig. 7-3) and packages (Fig. 7-4). This machine 

In the past it has been and still is common practice to use mainly winches or jet machines for preparatory of both woven and knitted fabrics in tubular form. Starting with the winch beck, machineries for pre-treatment processes have passed through several stages of development (jig, beam, jet, overflow), some paralleled in washing machines. The current trends towards smaller series have led to a comeback of the conventional systems using jigger machines (Fig. 7-5) for textile processing. 

Most knitted goods are batched process in winches which operate up to 140 C under pressure in an autoclave with usual fittings. The entire sequence of operations can be program controlled. In the modem winch machines (Fig. 7-7) the fab- 

Another one is spiral jet bleaching unit in which the woven and knitted fabrics can be pre-treated as shown in Fig. 7-9. In this machine, the fabric is moved in a spiral, in rope form, through the tube, using Jets that lifted the fabric out of one compartment and deposited in the next [7-9]. 

A comparison of typical bleaching recipes of cotton fabric for batch bleaching in different equipment with hydrogen peroxide is summerised in Table 7.1. When making-up a bleaching bath, naturally the quality of cotton, degree of pre-treatment, liquor ratio, equipment used and temperature must all be taken into account. 

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