Available from BioDefense Systems, a division of CLC Lubricants (Geneva, Illinois), is a compact filtration system for CNC machine tools, parts washers and other equipment that kills bacteria, viruses and fungi in coolants and other metalworking fluids without the need to add biocides. No biocides are needed to kill off the odor- and dermatitis-causing organic contaminants because the filter itself automatically releases elemental iodine as needed to eliminate microbial growths. The system is not intended as an alternative to complete systems that extract chips, fines and other solids. It is a supplement to such systems, designed solely to eliminate microorganisms without using biocides.
The system, which mounts on a carrying board, is available in OEM and portable versions. The BC 2000-P portable version is intended to be moved from machine to machine within the workplace as needed. The BC 1000-OEM version is intended for semipermanent installation on one machine. Whereas the OEM version relies on the machine’s coolant pump to circulate coolant through the filter, the portable version has its own pump (powered by shop air) for coolant flow through the filter.
The heart of both units is a Triosyn T50-I filter. Triosyn resin is a broad-spectrum biocidal polymer that is effective against bacterial spores, viruses, protozoa, algae and fungi. It interacts with microorganisms through an ionic reaction that is sensitive to their presence and concentration. The resin is produced by thermally fusing pure iodine crystals with a specialized polymer. During the process, a stable electrochemical bond is formed between the iodine and the polymer so that no free release of the iodine occurs. The electrochemical bond serves as a demand-release mechanism: It allows iodine molecules to be released from the resin in the presence of demand-causing microorganisms in amounts required to eliminate the source of the demand. In short, the resin uses iodine’s oxidation capabilities to kill microorganisms while its demand-release mechanism limits the release of free residual iodine, thereby minimizing any exposure to humans and the environment.
Components of the portable filtration system consist of the Triosyn filter cartridge (the white cartridge seen at left on the board), a larger (blue) prefilter with a 1-micron mesh that prevents solid contaminants from plugging the biofilter, an air-powered pump, pressure gages, and coolant supply and return lines. According to the manufacturer, the unit can be installed in 5 minutes or less. An operator or maintenance person carries the unit to the machine. The board is freestanding, but it can also be hung from hooks on the machine. An air hose is connected to the unit’s air diaphragm pump (see the photo at the left). The filter intake is inserted downstream of the machine’s coolant pump so that relatively particulate-free coolant will be passed through the biofilter cartridge. The return line goes to the machining area. The operator turns on the air, sets the pressure regulator to 30 to 40 pounds, and just lets the unit run. The unit filters at a rate of about 1 quart per minute, so it will take a little more than 3 hours to filter a 50-gallon sump.
The biofilter cartridge can filter from 2,000 to 3,000 gallons of coolant, depending on bioactivity, before it must be replaced. Studies by the company have shown that a filter used for a machine with a 40-gallon sump will last about 1 year; a machine with a 100-gallon sump may need two filters per year.
According to the company, the BioDefense coolant filtration system can save 40 percent compared with treating a machine’s coolant with biocides. The savings derive primarily from the elimination of the biocide costs plus savings in tank cleaning costs, coolant costs and coolant disposal costs. The system is also said to reduce dermatitis and respiratory problems for employees.