Airless Degreasers
The term “Airless Degreaser” has been applied to a range of equipment within the current cleaning technology market. There is no standardized, universally accepted definition for an Airless system. Historically, when we introduced this term in the 1990s, it referred to cleaning systems that pre-emptively evacuated air from the cleaning chamber prior to the application of cleaning agents. Complete evacuation of air, as implemented in semiconductor manufacturing processes, is cost-prohibitive and not necessarily required to meet cleaning efficacy and emission compliance standards. Field-operational solvent units typically achieve at least 95% air removal before introducing solvent into the chamber. Larger-capacity systems often achieve 99% or higher air evacuation due to the increased emissions associated with larger volume chambers.
The primary objective of involving an initial air removal step is to prevent oxygen contact with the solvent, thereby minimizing oxidative reactions. Once oxygen comes into contact with the solvent, it becomes notably challenging and costly to separate the solvent from the contaminated air, as the mixture constitutes a single-phase system requiring specialized treatment such as cryogenic condensation or activated carbon adsorption. Solvent recovery from an airless degreasing chamber can be efficiently achieved through simple condensation techniques. After evacuating air from the chamber, the system becomes hermetically sealed, preventing influx or efflux of air or solvent during operation. The final process stage involves vacuum-assisted drying to ensure residual moisture removal. Following drying, the chamber is restored to near-initial pressure and condition, excluding contaminants collected in a sump pump. The process concludes by re-establishing atmospheric pressure, reopening the chamber for part removal. Because the process initiates and terminates under vacuum conditions, this equipment configuration is often classified by the EPA as a Vacuum-to-Vacuum Degreaser, indicating a closed-loop system optimized for solvent reclamation and contaminant control.
An “Airless” system can be precisely characterized as a sealed operational vessel that facilitates the internal circulation of solvent in both liquid and vapor phases to carry out various cleaning operations. These operations encompass vapor degreasing, spray washing, liquid immersion, jet cleaning, ultrasonic cavitation, vacuum-assisted drying, and convective drying, all conducted within an enclosed environment devoid of any air-liquid interface or air-vapor mixture in the cleaning chamber.