GB1416337A - Method and apparatus for electroplating elongated metal elements - Google Patents

Abstract

1416337 Electroplating elongated metal elements S ANGELINI 10 Nov 1972 [19 Nov 1971 8 Feb 1972] 52041/72 Heading C7B Elongated metal elements (e.g. bars) are cleaned (e.g. with abrasive material) and then electroplated (e.g. with Cr). They enter and leave the electroplating tank through seals and pass through a tubular anode within the tank, the tubular anode being spaced from the entry seal and immersed in electrolyte. The elements move in a straight path of travel throughout the tank. As shown elements 10, Fig. 1, are fed by rollers 17, 18 through a cleaning device 26 and thence through an electroplating tank 29 having seals 30 at its entrance and exit. Then after the elements are washed with water from a nozzle 34. At both ends of the tank, the elements 10 are carried by stands 11 each provided with guiding idling rollers. The cleaning device 26 comprises abrasive material 27, Fig. 3, which is rotated over the surface of the elements and supplied with hot water at 28. Cathodic electrical contact for electroplating'is made to the bar at 23 and 23', Fig. 1, before the elements enter and after they leave the tank. Within the tank the elements 10 pass through a perforated tubular anode 31, Fig. 3. The plating current which flows through the elements from the upstream contact 23 preheats them before they enter the tank. The elements are further heated within the electroplating bath before entering the tubular anode by the bath itself. The electrical contact 23, Fig. 4, comprises copper plaits 24 which are held against the elements 10 by clamping elements 25. An alternative contact comprises mercury within a chamber 25", Fig. 5, provided with pneumatic sealing means 25' to allow the elements to pass therethrough. The sealing devices 30 at the tank entrance and exit may be pneumatic, Fig. 7, (not shown) or may comprise rows of overlapping flexible blades Figs. 17 to 20, (not shown). Electrolyte leaking from the seals 30 is collected at 30, Fig. 1, and recirculated. Temperature and composition of the bath are controlled by recirculating the bath through a cooling tank 32 and another tank (not shown) to which further electrolyte is added. The tank is provided with a suction hood 51, and a fume removing device (54), Fig. 14, (not shown). In an alternative arrangement Figs. 15 and 16, (not shown), the electroplating tank is located within a larger tank. Liquid leaking and overflowing from the electroplating tank is collected in the larger tank and recycled to the electroplating tank. The rollers 17, 18 feeding the elements 10 through the apparatus are coated with resilient material. Details of their mounting are illustrated in Figs. 2 and 9 (not shown).