Dry cleaning equipment

World capacity and demand for tetrachloroethylene were approximately 1100 and 845 thousand metric tons ia 1974, respectively. Although demand iacreased iato the mid-1980s, siace then demand for tetrachloroethylene has decreased significantly as a result of the phaseout of chlorofluorocarbons, the use of more efficient dry-cleaning equipment, and iacreased reclamation of waste solvent. World capacity and demand as of 1988 are provided ia Table 2 Several United States manufacturers have shut down faciUties ia the last fifteen years. Current manufacturers and their capacities are Hsted ia Table 3. United States production and sales history is shown ia Table 4. 

The addition of trichloro- ortetrachloroethylene to aluminium components in dry cleaning equipments is responsible for many accidents. The effect of the carbon tetrachloride/methanol mixture in the 1/9 proportion of aluminium, magnesium or zinc causes the dissolution of these metals, whose exothermicity makes the interaction dangerous. There is a period of induction with zinc, which is cancelled out when copper dichloride, mercury dichloride or chromium tribromide is present. 

Sail Star USA (Charlotte, NC)—U.S. subsidiary of one of Asia s largest dry cleaning equipment manufacturers. 

Tetrachloroethylene was first prepared ia 1821 by Faraday by thermal decomposition of hexachloroethane. Tetrachloroethylene is typically produced as a coproduct with either trichloroethylene or carbon tetrachloride from hydrocarbons, partially chloriaated hydrocarbons, and chlorine. Although production of tetrachloroethylene and trichloroethylene from acetylene was once the dominant process, it is now obsolete because of the high cost of acetylene. Demand for tetrachloroethylene peaked ia the 1980s. The decline ia demand can be attributed to use of tighter equipment and solvent recovery ia the dry-cleaning and metal cleaning iadustries and the phaseout of CFG 113 (trichlorotrifluoroethane) under the Montreal Protocol. 

However the acid is prepared, the sodium salt may be prepared as described in U.S. Patent 3,503,967 Five liters of methylene chloride were added to a clean dry vessel equipped with stirrer. 7-[a(4-pyridylthio)acetamido] cephalosporanic acid (1,000 g) was added to the vessel, followed by 350 ml of triethylamine. The resultant solution was treated with decolorizing charcoal for 15 minutes and filtered. A solution of sodium-3-ethyl-hexanoate (27.3%) in butanol-methylene chloride was added to the filtrate with stirring. Seven thousand five hundred milliliters of acetone was added. Crystallization occurred while stirring was continued several hours under dry conditions. The crystals were collected by filtration, washed with large volumes of acetone, and then dried in vacuo at 50°C to yield about 950 g of the title compound. 

Perchlor and trichlor are used as metal degreasing agents and as solvents in dry cleaning. Perchlor is also used as a cleaning and drying agent for electronic equipment and as a fumigant. 

The size of equipment can vary from a 200 W unit for a commercial dry-cleaning machine to systems of megawatt size for synthetic fibre processes. 

Distillation of tetrachloroethylene (formerly a dry-cleaning solvent) in new galvanised steel equipment produces traces of dichloroacetylene. This is toxic and may cause ill-health in those exposed. Should the acetylene chance to be concentrated (as in the sub-entry above), it is also very explosive. The galvanised metal becomes passivated in a few days and the effect was not found with other steels. 

Improving efficiency of PERC dry cleaning machinery Equipment manufacturers are able to offer advanced machinery complying with the stricter emission control standards, to the extent that the consumption of PERC has reduced by more than 50% since 1980, and in some countries 90% - misguided efforts that could have been better directed towards removing this toxic substance totally. 

Uses. Solvent for cleaning electronic equipment and degreasing of machinery refrigerant dry cleaning agent... 

Manufacturing equipment should be designed, located, and maintained to suit its intended purpose. Repair and maintenance operations should not present any hazard to the quality of the products [10]. It should be designed so that it can be easily and thoroughly cleaned. It should be cleaned according to detailed and written procedures and stored only in a clean and dry condition. Washing and cleaning equipment should be chosen and used in order not to be a source of contamination. 

Forth, K., (assoc, ed.). October 1985. "Stripped Clean and Dry." Aviation Equipment Maintenance. 

Air-dry the cleaned equipment before use on the next sample. If equipment will not be immediately used, keep it in a clean storage container or wrap it in aluminium foil. 

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