GB525236A - Improvements in or relating to degreasing metal strip - Google Patents

Abstract

525,236. Degreasing metal strip. BOOTH, W. E., AND IMPERIAL CHEMICAL INDUSTRTES, Ltd. Feb. 20, 1939, No. 5641. [Class 91] Metal strip is degreased by treatment with a volatile solvent, the vapour of which is heavier than air, in a closed apparatus containing means for maintaining a solvent vapour zone in the vessel and fitted with a tube extending vertically and fitted with cooling means through which the strip is withdrawn. In the preferred form of the invention the vertical exit tube is continued down into the vessel to a point below the solvent vapour level, and the entrance of the metal strip is effected through a vertical liquid cooled tube similar to the exit tube. Alternatively, the strip may be introduced and removed through the same tube. The strip in leaving the apparatus preferably passes rods or rollers near the point where the strip leaves the vapour zone, so that each surface of the strip makes contact with at least one such roller. In an example a closed vessel 1 with a sump 2 containing a heating element 3, is provided with two jacketed vertical tubes 6 and 8 for the entrance and exit of the metal strip. The tube 8 is extended into the vessel at 11 and both tubes are pivoted to facilitate the introduction of the strip. The strip 16 passes over a roller 10, enters the vessel through tube 6, passes over the second and third rollers 10, over the three staggered rods 12 and out over the fourth roller 10. Cooling means 5 place an upper limit to the vapour in the vessel and condensate therefrom flows through a slot 14 in a trough 13 to wash traces of insoluble matter from the strip.