ABSTRACT
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265 The Ideal Solvent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266 Cold Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
Pail and Scrub Brush . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267 Hand Wipe. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267 Aerosol Spray . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267 Recirculating Overspray(“Sink-on-a-Drum”) Parts Washer . . . . . . . . . . . . . . . . . . 267 Immersion Cleaning, Single-Dip Tank, with Manual Parts Handling . . . . . . . . . . 268 Automated Immersion Cleaning, Multiple-Dip Tanks. . . . . . . . . . . . . . . . . . . . . . . 269
Heated Solvent Cleaning Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270 Heated Dip Tank. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270 Vapor Degreasing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271
INTRODUCTION
In light of current and expected regulations, the trend of the 1990s has been to adopt aqueous (water-based) cleaning systems. In some applications, this may be the best choice. However, in other applications, water just does not work. Some considerations and problems include requirements for pretreatment of water supply, waste stream handling requirements and costs, limited efficacy of cleaning due to low solvency for many soils of interest and high surface tension, energy costs of heating and drying, requirements for rinsing and drying, high total cycle time, compatibility/flash rusting, complicated bath maintenance, high capital equipment costs, high maintenance costs, and large equipment footprint.
