Description of the solvent degreasing process

Back to Solvent degreasing in metal industry

Solvent degreasing

Solvent degreasing is usually by means of chlorinated hydrocarbons (CHC), alcohols, terpenes, ketones, mineral spirits or hydrocarbons. CHCs are used because of their good cleaning efficiency and universal applicability, as well as their quick drying and incombustibility, but their use is restricted by environmental and health legislation. All solvents affect the central nervous system and exposure should be controlled.

There are two types of process:

• Cold cleaning: The workpieces and/or substrates are immersed in the solvent or cleaned in a stream of solvent. In some cases, the solvent is pumped round taking the liquid from near the top of a holding tank, leaving dirt to settle at the bottom. The tank is cleaned periodically.

• Vapour cleaning: The solvent is vaporised in a purpose-built bath and the cold component suspended in the vapour. The vapour condenses on the component dissolving grease and drained off with the dirt and grease, leaving the component clean and dry. The most common solvents are CHCs. As the vapours are heavier than air they are contained in the bath. Hydrocarbon solvent may be used.

Source: BAT Surface Treatment of Metals and Plastic, Aug. 2006.

Back to Solvent degreasing in metal industry