Firbimatic Metal Cleaning Division hermetically sealed solvent systems, for surface degreasing and treatments, feature very low consumption levels, bound above all to the residual solvent in the distillation oils, which are periodically drawn from the still, as envisaged in the specifically written operating instructions.
Typical value of residual solvent in distillation oils < 1 %, meaning 0.1 l every 10 l of sludge.
Important international standards regulate and limit the maximum levels of atmospheric emissions and solvent consumptions. In the case of the perchloroethylene (risk phrase R40), the emission limit adopted is 100 g/h.
More specifically, the VOC Directive indicates a limit of 20 mg/Nm3 on excess mass flow of 100 g/h. This is effective for all compounds classified R40 (Perchloroethylene and Methylene Chloride).
Firbimatic Metal Cleaning Division systems comply with emission limit values (100 g/h of residual solvent in stack) by exploiting closed-cycle systems that prevent emissions into the atmosphere or in the workplaces throughout the whole cleaning cycle; the system is hermetically sealed and, thanks to the efficiency of the integrated cooling system, it is possible to recover more or less 100% of the solvent used by condensing and subsequently separating it.
The solvent recovery system is closed-cycle and is well within the limit of 100 g/h in all small capacity systems.
Medium/large capacity metal cleaning machines, or rather those made up of a washing chamber with volume of >1 m3, require a more sophisticated solvent abatement/recovery system, which after the condensation cycle, further absorbs the remaining solvent in an active charcoal filter.
In addition to this, the residual perchloroethylene vapours, extracted by the fan when the loading door is opened, are conveyed to the same active charcoal filter which, by exploiting the absorption principle, traps the solvent, even if modest in quantity, which in the traditional version is directly emitted into the atmosphere.
Periodically, the active charcoal needs regenerating: in the systems of Firbimatic Metal Cleaning Division, regeneration is performed at the end of the work shift by means of a jet of hot air which, by passing through the charcoal bed (“stripping” stage), allows the solvent to be recovered and used again completely after condensation.
Technological progress now means that very important abatement results can be achieved; old degreasing plants consisting of open tanks featuring cooling systems on the free edge produced (and still produce today) atmospheric emissions between 1.8 and 5.6 kg/h per m2 of tank surface, compared to the current 100 g/h.