Device for regenerating hydrochloric copper chloride etching solutions

Claim 1

In a device for regeneration of spent hydrochloric copper chloride etching solution which is utilized in printed circuit board manufacture for etching non-galvanized printed circuits, wherein etching and regeneration occur in separate etching and regeneration means between which the etching solution is circulated cyclically or continuously and regeneration occurs with an oxidizing gas, the improvement comprising wherein: in combination said regeneration means comprises; an enclosed regeneration housing positioned in a flat upright container which holds a hydrochloric copper chloride etching solution therein, said housing having an interior wall defining a chamber in fluid communication with said upright container; a means for providing an oxidizing gas in controllable fluid communication with an upper area of said chamber, said oxidizing gas being selected from the group consisting of oxygen, chlorine and a mixture of oxygen and chlorine; said etching means including a means for providing spent hydrochloric copper chloride etching solution in fluid communication with said upright container and with said upper area of said chamber; means for spraying said spent etching solution into said upper area of the chamber for contacting said etching solution with said oxidizing gas so that regeneration of said etching solution occurs, consumption of at least a portion of said oxidizing gas occurs and regenerated etching solution collects in said upright container from where such regenerated solution flows back to said etching means; and two level switch means positioned at different levels along the interior wall of said regeneration housing within the chamber thereof for respectively opening and closing said means for providing an oxidizing gas so as to equalize the subatmospheric pressure arising within said chamber because of gas consumption and thus maintain the relatively slow increase of etching solution within said chamber within optimum limits.