ES379369A1 - Apparatus for treatment of fabrics with liquid ammonia - Google Patents

Abstract

A machine for treating fabrics with liquid ammonia to improve their stretch and resistance to shrinkage and creasing comprises a chamber, a first feed means for feeding fabric into the chamber means in the chamber for impregnating the fabric with liquid ammonia, a second feed means for removing the fabric from the chamber and means between the first and second feed means for controlling their relative speeds and thereby applying a controlled longitudinal tension to the fabric. In the form shown the chamber is divided by partitions 50, 52 into three compartments A, B and C. In compartment A, the atmosphere of which is saturated with ammonia from a liquid ammonia trough 134 heated by steam lines 136, 138, the fabric passes under a roller 116 in a liquid ammonia trough 112 and is thereby saturated with liquid ammonia. The saturated fabric is then looped around guide rolls 84, 86, 94, 96, the number of such rolls employed governing the time of residence of the fabric, and then passes through sealing nip rolls 160, 162 into compartment B. Here the fabric is stretched transversely in a tenter machine 164 and is then heated by passing around heater drums 176, 178, 180 and 184. The atmosphere in B is saturated with ammonia vapour from a liquid ammonia trough heated by steam lines 170, 172. The fabric leaves compartment B through sealing nip rolls 240, 242 and passes into compartment C wherein it passes around guide rollers whilst being subjected to steam jets to remove the residual ammonia. The fabric passes from the chamber through sealing nip rolls 312, 314, 316, 318 and enters drive rolls 324, 326 whence it passes over another tentering frame 340, being first sprayed with water, if necessary, to allow tentering, and then around the dryer drums 344, 346 on which it is held by a felt 348 which preserves its stretched width whilst drying and is finally wound on to a take up roll 402. Optionally a compressive shrinker may be located between the tenter and the drying drums (Fig. 1C not shown). The longitudinal tension in the fabric as it enters compartment A is controlled by adjusting the speed of feed rolls 24, 26 relative to the speed of rolls 106, 108, the speed of the motor driving roll 24 being controlled by a rheostat, the setting of which is determined by the position of a roll 20 mounted on a pivoting lever arm 34, the arm actuating an air valve for a pneumatic cylinder 42 the piston of which actuates the rheostat. Similarly, movable tension roll 118 regulates the tension in the fabric between rolls 106, 108 and the heated drums in B, and movable tension roll 202, by controlling the speed of the take-up roll, regulates the tension between the heated drums and that roll. Means are provided for venting the compartments and preventing escape of ammonia therefrom. Furthermore the fabric may be saturated with a resin precondensate as well as the ammonia liquid in trough 112, the resin being cured in compartment C.