Patent GB-785693-A (GB)
Title: Improvements in or relating to process and apparatus for chemical nickel plating
IPC: C23C18/16
Filed: 1953-07-09
Abstract: 785,693. Coating with nickel. GENERAL AMERICAN TRANSPORTATION CORPORATION. July 9, 1953 [July 19, 1952], No. 19063/53. Class 82(2)  A continuous process of chemically plating a solid catalytic material with nickel comprises (a) providing an aqueous solution of a nickel salt and a hypophosphite, the ratio of nickel to hypophosphite ions being within a first predetermined range, the absolute concentration of hypophosphite ions being within a second predetermined range and the pH value of the solution being within a third predetermined range, (b) storing a first portion of said solution at a temperature well below its boiling point in a reservoir, (c) holding a second portion thereof at a temperature slightly below its boiling point in a plating chamber, (d) circulating such solution from the reservoir to the plating chamber .and back to the reservoir, (e) heating the solution to the higher temperature after withdrawal from the reservoir and before introduction to the plating chamber, (f) cooling the solution to the lower temperature, after withdrawal from the plating chamber and before return to the reservoir, (g) immersing the body of catalytic material in the solution in the plating chamber, (h) withdrawing the body therefrom after a time interval dependent upon the thickness of plating desired and (i) adding during such interval soluble reagents to the solution in the reservoir to maintain in the plating chamber during such interval the ratio, absolute concentration and pH value within the respective predetermined ranges. Fig. 1 shows diagrammatically the general arrangement of coating apparatus; coating solution passing from the tank 10. through coils 15 where it is steam heated, into a  coating tank 12. passing thence through a heat exchanger 29 and pump 19 back to the tank 10. For coating the inner surface 11a of a tank 10a, Fig. 2, a reserve tank 35 is provided comprising a storage compartment 36, having baffles 43 and communicating at 42 with a regeneration compartment 37 having mixers 44. The compartment 36 has a drainage valve 38 and valves 58, 60 inter-connected by a by-pass conduit 61, and connected respectively to a pump 47 and filter 49, the discharge side of the pump 47 also being connected to the filter. The outlet of the filter 49 is connected to a condenser 50, a rotameter being -provided at 73. From the condenser 50, liquid passes to the tank 10a or to a plating tank 56, through ,a conduit 78 from which it may also be passed back at 84 to the compartment 37. Steam from the conduit 87 and water vapour from the tank 53 are fed by a steam jet vacuum pump 54 into the condenser 50 to heat and dilute the solution. Steam may also be fed into the condenser 50 through an auxiliary live steam injector 91 from the conduit 87: a by-pass conduit 95 including check valves 96, 97 and a temperature control valve 98 is also provided, the valve 98 being connected by a capillary tube 99 to a temperature control bulb 100. Solution from the tanks 10a and 56 passes through the conduit 103 to the tank 53, the lower portion of which is connected to the upper portion of the tank 52, the lower portion of the latter being connected to the pump 48 which returns the solution to the compartment 37: a rotameter is provided at 119. The upper portion of the tank 52 is connected to the condenser 51, the upper portion of which is connected to a cool water supply at 90‹F. and to the jet mechanism of a pump 55 also connected to the steam supply conduit 87: the pump 55 discharges to atmosphere. The solution in the tanks 10a, 56 is at 210‹F., that leaving the tank 53 is at 180‹F. and is more concentrated due to evaporation in the tank 53, and that leaving the tank 52 is at 150‹F, and still more concentrated. The tank 10a is rotated about its longitudinal axis as described in Specification 785,697. Hydrogen escapes to atmosphere from the tank 10a through conduits 134. 135. Regenerating components are added in the compartment 37. Specifications 761,062 and .785,698 also are referred to.