GB348168A - Improvements in or relating to the manufacture of artificial silk - Google Patents

Abstract

<PICT:0348168/IV/1> In the production of artificial silk by the dryspinning method, the temperature of the spinning solution up to the time that it leaves the spinning nozzles is controlled by means of a heat exchanger through which cooling fluid is caused to flow in relatively large quantities and at a constant initial temperature which is not more than 2 DEG C. below the desired temperature of the spinning solution. Preferably, the cooling fluid after leaving the heat exchanger is cooled to a temperature below that at which it is to enter the heat exchanger, and is subsequently heated to the required initial temperature. The cooling fluid may be water or brine. In the drawing a large warm water container a provided p with a heating device is equipped with an automatic temperature regulator b, and supplies water to the heat exchangers d which are associated with the spinning nozzles. A pump c forces the water to the heat exchangers d of the spinning vessel e. The admission pipes for the water are arranged in parallel, and the outlet pipes deliver into a common collecting pipe f. The water which has been heated somewhat in passing through the heat exchangers is led to a vessel g where it is cooled to a temperature below that of the container a to which it is returned to be heated to the desired initial temperature. If there is a sufficiently large temperature difference, the pump may be dispensed with and the liquid circulated through the apparatus on the principle of the thermosiphon. In spinning cellulose acetate silk the temperature of the spinning cell may be 90 DEG C., and that of the solution at the orifices of the nozzles may be maintained at 35 DEG C. by supplying water to the heat exchangers at 33 DEG C. The water after leaving the heat exchangers is cooled in the vessel g to about 30 DEG C., and is reheated in the container a to 34 DEG C. A loss of about 1 DEG C. takes place between the container a and the spinning machine. Specification 323,031, [Class 2 (ii), Cellulose &c.], is referred to.