GB1110530A - Process for the purification of coating lubricant - Google Patents

Abstract

1,110,530. Coating with lubricant. PYRENE CO. LTD. 25 Nov., 1966 [26 Nov., 1965], No. 52978/66. Headings B2K and B2L. In a process in which a lubricant coating is formed on a succession of metal surfaces by treating the surfaces with a fatty acid soap lubricant composition maintained in a tank, the lubricant composition is withdrawn from the tank during the process, is purified of impurities by centrifuging, is deaerated and reintroduced in to tank. In the arrangement shown lubricant from article immersion tank 1 drains via pipe 3 to a centrifugal purifier 5. Water and/or steam may be added via pipes 2 and 4 respectively. In the purifier, purified lubricant composition is removed by skimmer 7 and fed to 'thin film' type deaerator 11 from whence it drains back to tank 1. The heavy metal soaps and other impurities 10 are drained from the purifier through outlet 8. The flow rate through the purifier is at least 1 gal. per minute and preferably from 2 to 6 gals. per minute and the centrifuge may be rotated at from 1000 to 2000 r.p.m. In one application, steel blanks for cold forming which had been coated with zinc phosphate coating solution were given a lubricant coating by immersion for 5 minutes in a solution of 0.5 pounds sodium stearate soap per gallon at a temperature between 65 and 85‹C. A portion of the lubricant solution was drained from tank 1 and passed at the rate of 2 gallons per minute through a bowl type centrifuge rotating at 1400 r.p.m. Lubricant solution removed from the centrifuge by skimmer 7 was then spread as a film about 0.5 cm. thick over the spreader plate 13 and returned to tank 1. Lubricant material analyzed before and after centrifuging showed iron contents of 0.030% and 0.025% respectively.