| Manufacturers and plant managers face a difficult | | | | rate. |
| challenge when choosing a surface cleaner. There are | | | | After drying is complete, the vapors travel through |
| many options on the market, ranging from aqueous | | | | an activated carbon recovery system, which reduces |
| or semi-aqueous solutions, to flammable hydrocarbon | | | | further the already negligible emissions produced by |
| solvents, or to fluorinated/brominated solvents. In this | | | | the machine. |
| crowded field, one process is exceptional in its ability | | | | Using a sealed chamber system prevents solvent |
| to produce a clean, dry part at a modest price, the | | | | loss. By distilling the soil laden solvent for re-use, |
| chlorinated solvent. | | | | hermetically sealed units also save companies on |
| Over the last two decades, manufacturers moved | | | | cleaner costs over that of alkaline based blends that |
| away from chlorinated solvents due to | | | | are used in aqueous systems and must be replaced |
| misunderstood environmental concerns. Chlorinated | | | | due to drag out and steam exhaust continuously. |
| solvents such as perchlorethylene, trichloroethylene, | | | | These hermetically sealed units are appropriate for a |
| and methylene chloride dumped into the same | | | | wide range of industries. Cutlery, Electrical contact |
| category as111-trichloroethane (methyl chloroform) | | | | Manufacturing, shoe soles, metallic lights, working |
| which was phased out of production, due to its | | | | polyurethane, turned steel, steel pipes, steel coils, |
| ozone depletion potential. Meanwhile, worldwide the | | | | aluminum parts, small diameter steel and copper pipes |
| other chlorinated solvents continue to be viewed as | | | | up to 25 feet, brass parts, heat exchangers, locks, |
| acceptable substitutes for ozone depleting solvents. | | | | keys, padlocks, small bearings, plumbing fittings, |
| It would be unwise to rule out chlorinated solvents. | | | | glasses, TV components, circuit boards, micro chips, |
| They are not appropriate for every part, but there | | | | switch components, measuring instruments, lighting |
| are times when they are the proper cleaner for the | | | | articles, refrigerator parts, aircraft and weapon |
| application. In these instances, it is better that the | | | | components, medical implant, surgical appliances, |
| manufacturer invest in a machine able to make use | | | | dental parts, dental equipment, dental supplies and |
| of chlorinated solvents, rather than attempt a parts | | | | frames, eye wear, toys, ball point pens, Teflon seals, |
| cleaner with an alternative that does not produce the | | | | fasteners, and needles are all industries that benefit |
| same quality. | | | | from the hermetically sealed process. |
| Hermetically sealed solvent cleaning systems perform | | | | Chlorinated solvents will continue to be available. PERC |
| their cleaning operations within a sealed chamber in | | | | demand has remained steady or increased in recent |
| which solvent is introduced only after the chamber is | | | | years as a result of their use as raw materials in the |
| closed. By sealing the process, the machine shields | | | | production of refrigerant alternatives to CFCs. The |
| operators from exposure to the chlorinated solvent | | | | producers of this solvent remain committed to |
| vapors. The used soil laden solvent is then distilled, | | | | serving their markets for many years to come. |
| then condensed back to fluid for re-use in the next | | | | PERC can be used safely. From the point of view of |
| cleaning operation. | | | | health and the environment, the chlorinated solvents |
| The process is particularly effective with parts that | | | | are among the most thoroughly studied industrial |
| contain recesses, blind holes, perforations, crevices, | | | | chemicals. Animal tests and epidemiological studies |
| and welded seams. The solvent vapors are able to | | | | indicate that when the solvents are handled, used, |
| effectively penetrate these hard to reach areas, as | | | | and disposed of in accordance with recommended |
| well as complicated assemblies. In addition, solid | | | | and mandated practices, they do not cause adverse |
| particles left in the part from the manufacturing | | | | health or environmental effects. Last complete study |
| process are removed by the mechanical washing | | | | covering this subject was carried out by ACSH and |
| action of the machine, which can include an ultrasonic | | | | published in July 2001. |
| transducer to implode heavy soil and oil deposits by | | | | Picking a parts cleaner is a critical part of the |
| breaking the surface tension from the metal surface. | | | | production process. The proper chemistry must be |
| Hermetically sealed machines are ideal for many | | | | used, in the right concentration, and at the correct |
| different manufacturing processes. They are able to | | | | temperatures in order to properly clean the part. If |
| remove tough soil from parts as well as reaching into | | | | the right chemistry is not chosen, then it is possible |
| tiny crevices contained in parts with convoluted | | | | that the part will be damaged or not cleaned to |
| shapes. The stages of a hermetically cleaned parts | | | | customer specifications. |
| include solvent spray gross cleaning, immersion, and | | | | Far from replacing chlorinated solvents with |
| vapor rinsing before exiting the machine, leaving them | | | | alternative cleaning technologies, manufacturers may |
| perfectly cleaned. Air re-circulation and vacuums dry | | | | wish to seriously consider surface cleaning with |
| the parts in their final stages, removing solvent still | | | | chlorinated solvents as the most efficient, effective |
| present on the part and also reducing the | | | | and economical cleaning process for precision |
| consumption of the machine to a near 0 emission | | | | products. |