Improvements in and relating to the ageing of viscose

In the ageing of viscose as it passes from the point at which it is formed to the point at which it is delivered to a spinning or casting machine it is passed through one or more heat-exchangers having a small capacity compared with the total volume of the viscose between the two points so that any temperature deviations of the viscose from a predetermined ageing temperature are corrected and the viscose is aged in a substantially uniform manner. The viscose is preferably passed through a heat-exchanger directly after passing through a stage where the viscose is particularly liable to undergo temperature changes, for example, a filtration stage. Air conditioning of the "caves" containing the viscose storage tanks and auxiliary equipment may also be employed to control the temperature of the viscose. The heat exchanger may be a block of high heat transference material, for example compressed carbon, through which two sets of holes extend e.g. at right angles, the viscose being passed through one set and the heat-exchanger fluid through the other. In the example freshly prepared viscose passes successively through a filter, a heat exchanger, a storage tank (which may be situated in an air-conditioned atmosphere), a drop tank, a pump, a filter, a second heat exchanger, a deaerator, and a second pump to a spinning machine, the various units being connected by pipes in the usual manner. The heat exchangers are supplied with a cooling or heating medium, such as brine, in order to adjust the temperature of the viscose to the desired ageing temperature.