Electro plating bath - is covered by a closed suction extn. hood with material passage openings shrouded by air curtains

摘要

To work with process solns. which emit hazardous matter, contained in open vessels (3) for items (2) to be immersed for treatment and then extracted, enclosed suction units (8) are over the vessels (3) to extract and remove hazardous matter through air vol. The shrouding has openings for the items (2) to be inserted and removed, covered by an air curtain (14). The pressure within the closed suction system (8) is lower than in the ambient environment. The air extracted by the suction system (8) is used to develop the air curtains (14), and the air is cleaned of hazardous matter during recirculation. Pref. the process soln. is cooled to temp. of 274-293 K, and the recirculated air is cooled. The processing station with suction extn. is at the end of the assembly. The air curtain (14), covering the openings, for material (2) insertion and extraction, is switched off while material is passed through them, and air is extracted (8) from the station while material (2) is moved through, and the extracted air is released or passed to another station than for air curtains (14). While material (2) is moved through the disconnected air curtains, the air recirculation system is switched off, and air extracted by suction (8) is released. The recirculated air passes through an air washer (16), with droplet extractor (17) before or after it. The fluid (18) used in the air washer (16), whether alkali or acid, is cooled and recirculated and cleaned of any hazardous matter carried in it. Heat pump is used to generate the required cooling capacity, and its generated heat is used for heating bath at raised temp. in the assembly (1) or in other assemblies. USE/ADVANTAGE - The system is used for electro-plating and similar surface treatment applications where there is liq. chemical action. The method allows liqs. contg. pyrroles and the like to be used in open vessels.