Vapor degreasing is a

surface finishing Surface finishing is a broad range of industrial processes that alter the surface of a manufactured item to achieve a certain property. Finishing processes may be employed to: improve appearance, adhesion or wettability, solderability, corrosion re ...

process. It involves

solvents A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for p ...

in vapor form to cleanse the workpiece in preparation for further finishing operations.

Process

The acting principle behind the vapor degreaser process is that the solvents will dissolve the contaminants on the workpiece and remove them by dripping off the part. A basin of solvent is set up with a

heating coil A heat exchanger is a system used to transfer heat between a source and a working fluid. Heat exchangers are used in both cooling and heating processes. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contac ...

to bring the solvent to

boil A boil, also called a furuncle, is a deep folliculitis, which is an infection of the hair follicle. It is most commonly caused by infection by the bacterium ''Staphylococcus aureus'', resulting in a painful swollen area on the skin caused by an ...

. As the solvent evaporates it rises to the fill-line in the chamber, above which is air with a much lower density than the solvent. This contains the

vaporized Vaporization (or vaporisation) of an element or compound is a phase transition from the liquid phase to vapor. There are two types of vaporization: evaporation and boiling. Evaporation is a surface phenomenon, whereas boiling is a bulk phenomenon. ...

solvent in a closed space where the workpiece is placed. The solvent

condenses Condensation is the change of the state of matter from the gas phase into the liquid phase, and is the reverse of vaporization. The word most often refers to the water cycle. It can also be defined as the change in the state of water vapor to ...

on the more frigid workpiece and the now liquid solvent dissolves the greases on the part. With the

impurities In chemistry and materials science, impurities are chemical substances inside a confined amount of liquid, gas, or solid, which differ from the chemical composition of the material or compound. Firstly, a pure chemical should appear thermodynam ...

contained in the liquid beads, the solvent runs off the part. Some systems are designed to capture and reclaim this solvent, making the process much more

economical An economic system, or economic order, is a system of production, resource allocation and distribution of goods and services within a society or a given geographic area. It includes the combination of the various institutions, agencies, entities ...

. Other adaptations to the simple system include: *Several tanks for solvents and rinsing *Having a solvent spray to coat the workpiece prior to entry into the chamber to speed up the process and to allow for more complex parts to be cleaned. The spray must be below the vapor line. *Vacuum degreasers

Benefits

n-propyl bromide 1-Bromopropane (''n''-propylbromide or nPB) is an organobromine compound with the chemical formula CH3CH2CH2Br. It is a colorless liquid that is used as a solvent. It has a characteristic hydrocarbon odor. Its industrial applications increased dr ...

(nPB) based solvents for vapor degreasing, in comparison to other solvents for vapor degreasing, are environmentally friendly. nPB solvents are non flammable (no flashpoint), non chlorinated, U.S. EPA SNAP approved, non hazardous waste (per U.S. Department of Transportation), and non ozone layer depleting. However, "Exposure to 1-BP can cause irritation (for example, of the eyes, mucous membranes, upper airways and skin) and can damage the nervous system. Neurologic effects can appear as headaches, dizziness, loss of consciousness, slurred speech, confusion, difficulty walking, muscle twitching, and/or loss of feeling in arms and legs." *Can be used on electronic parts to remove excess

oil An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) & lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturated ...

, grease,

wax Waxes are a diverse class of organic compounds that are lipophilic, malleable solids near ambient temperatures. They include higher alkanes and lipids, typically with melting points above about 40 °C (104 °F), melting to give low ...

and other non-water

soluble In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution. The extent of the solubil ...

particles because water is not used. *Used where water-based system are impractical. *Cleans and prepares part surfaces for various finishing processes like

painting Painting is the practice of applying paint, pigment, color or other medium to a solid surface (called the "matrix" or "support"). The medium is commonly applied to the base with a brush, but other implements, such as knives, sponges, and ...

welding Welding is a fabrication (metal), fabrication process that joins materials, usually metals or thermoplastics, by using high heat to melt the parts together and allowing them to cool, causing Fusion welding, fusion. Welding is distinct from lower ...

soldering Soldering (; ) is a process in which two or more items are joined by melting and putting a filler metal (solder) into the joint, the filler metal having a lower melting point than the adjoining metal. Unlike welding, soldering does not involv ...

, and bonding.Kalpakjian, Serope. ''Manufacturing Engineering and Technology'' Prentice Hall: Upper Saddle River, NJ. 2006. p. 1078. *Issues of part

oxidation Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a d ...

and

water spot A water spot is an area of dried mineral deposits left on a surface after being allowed to air dry. Water quality, specifically the amount and type of minerals in the local water supply as measured by the total suspended solids or TSS test an ...

s are not present. *With vacuum degreasers, there is no solvent emitted. However they have a high cost and low production rate.

References

{{reflist Metalworking