| 摘要 |
507,761. Refining paraffin wax. BURMAH OIL CO., Ltd., and HARLEY, C. R. S. Dec. 16, 1937, No. 34912. [Class 91] Paraflin wax is refined by impregnating a carrier of absorbent and reinforcing material to form a solid film, heating the impregnated carrier, and subjecting it to momentary pressure so as to release and remove the sweats. The carrier may be an endless band of cotton duck or a similar wool fabric and may be heated and pressed at successively higher temperatures; in examples, the temperature is increased in small stages from 110‹ or 130‹ to 180‹ F., and sweats removed at each stage. As described, a dry endless band a is immersed in molten wax in a jacketed tank c, excess wax may be removed as the band moves out of the tank by two adjustable doctor blades (not shown), and the band may be cooled in air or passed through cold water in tank d to solidify the wax. When a sufficient length of the band has been impregnated with solid wax the band is passed comtinously through tanks c, d and between sets of rolls b, b immersed in water or other liquid in sweating tanks e. The water is kept at successively higher temperatures in successive tanks by electric heating with thermostatic control. The band is brought up to the necessary temperature in tanks e before reaching the rolls. Each pair of rolls is enclosed in an open casing h, so that the sweats may be,skimmed off and collected separately as they rise to the surface of the water. In a modification. Fig. 3 (not shown), the band moves horizontally through the sweating tanks. The pressure on the band may be adjusted by tensioning a spring which raises the lower roll. A smooth temperature gradient may be maintained in the sweating tanks by thermostatic control. Removal of the sweats may be aided by circulating the water in tanks e or by adding surface-tension reducers e.g., soaps, there may be more than two rolls in a set, and the rolls may be ribbed. The band is dried after leaving the last sweating tank. |
