Cleaning with Solvents while Preserving the Environment
Where drying is concerned, chlorinated hydrocarbons offer advantages over HCs and modified alcohols that have low evaporation rates. Generally speaking, they dry faster and more completely, making them preferable for parts with critical drying characteristics, for example complex geometries and capillaries.
Vacuum Technology – State-of-the-Art Cleaning with Solvents
Today, solvents are used in fully closed cleaning systems that fulfill applicable requirements for reduced volatile organic compound (VOC) emissions. Modern systems are equipped with an integrated distillation unit that continuously conditions the solvent, thus assuring consistent cleaning quality.
A trend towards cleaning systems that are operated under full vacuum has been apparent for quite some time now. Using vacuum for combustible solvents (HCs and modified alcohols) eliminates the need for additional explosion protection. Other process engineering advantages include system safety with regard to leaks, and low-temperature distillation. Consequently both the solvent and the oil introduced to the process are subjected to less stressing.
Distillation of CHCs generally takes place at low temperatures – the boiling point of perchlorethylene is approximately 120° C (280° F). Fewer cracking products occur as a result, and oils with a boiling point of, for example, 140° C also can be distilled out reliably. In the case of hydrocarbons and modified alcohols, the distillation point lies within a range of 175° C (347° F) to greater than 200° C (392° F), and thus one runs the risk of distilling an oil with a low boiling point along with the solvent and impairing the quality of the cleaning agent as a result.
Saving Energy, Providing Flexibility
Due to the fact that solvent regeneration is the most energy-intensive step in this type of cleaning process, modern solvent systems are equipped with heat recovery devices. These devices are being continuously improved. Today’s systems also are equipped with automatic distillation power adjustment to adapt to actual conditioning requirements, thus further reducing energy consumption and operating costs.
The trend towards full vacuum technology is expanding the possibilities for universal use of solvent-based cleaning systems. For example, systems are available which can be operated with hydrocarbons, modified alcohols or chlorinated hydrocarbons. These systems contribute to investment security for the user, in the event that changing requirements or new components make it necessary to switch to a different solvent.
Solvents are traditionally regarded as degreasers. Contaminations in the form of particles, such as chips, which are trapped in the oil or grease are generally cleaned away as well, because they no longer adhere to the degreased surface. To fulfill stricter particle count requirements, the systems are frequently equipped with several media tanks, ultrasonic generators and appropriate filtering technology, as well as special design features. These include, for example, an electropolished process chamber and wall rinsing, which assures that any particles that adhere to the process chamber walls are washed away. Systems of this sort are also used for validated processes, for example in the field of medical technology.
Learn More at parts2clean
Which solvent is best for the respective cleaning or degreasing task? Which types of system technology are available for assuring environmentally sound, reliable and economic cleaning? Answers to these and other questions covering all aspects of industrial cleaning are provided at parts2clean, the international trade fair for industrial parts and surface cleaning. The 10th parts2clean will take place at the Stuttgart Exhibition Centre in Germany from the 23rd through the 25th of October, 2012.
The exhibition portfolio encompasses systems, processes and process media for degreasing, cleaning, deburring and pre-treatment of parts and surfaces, special processes, parts baskets and workpiece carriers, handling and process automation, cleanroom technology, quality assurance, test methods and analysis procedures, media treatment and disposal, job-shop cleaning, corrosion protection, preservation, packaging, research and technical literature.