Process for recovering the overspray of aqueous coating agents during spray application in spray booths

US5453301A · kind A · utility

Assignee

• Herberts Gesellschaft mit beschrankter Haftung · DE

Inventors

• Dietrich Saatweber · Wuppertal, DE
• Waltraud Krumm · Schwelm, DE
• Bernhard Richter · Puchheim, DE
• Dirk Holfter · Hagen, DE

Key dates

• Filing date: Oct 28, 1994
• Grant date: Sep 26, 1995
• Expiry date: Oct 28, 2014

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P70/10
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

Continuous process for recovering the overspray of aqueous coating agents during spray application by collecting it in an aqueous washing liquid which is continuously circulated in a circuit (A) to the spray booth, where the solids concentration of said washing liquid is maintained within the range of 1-1.5 wt.-%, whereby a part of the washing liquid containing overspray is fed to a first ultrafiltration circuit (B) in which the solids concentration of the circulating liquid is maintained within a range of 8-15 wt.-%, a part of the circulating liquid from ultrafiltration circuit (B) being fed to a further ultrafiltration circuit (C) in which the solids concentration of the circulating liquid is maintained approximately constant within a range between 35 wt.-% and the solids concentration corresponding to spray viscosity of the aqueous coating agent, whereas the permeate from circuits (B) and (C) is returned to circuit (A) in order to top up the washing liquid and at least a part of the liquid circulating in ultrafiltration circuit (C) is used as an aqueous coating agent for spray application in the spray booth or for preparation thereof.