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Extraction of Welding Fumes and abrasive Dust with a central Dust Collector System - Cartridge Filter - 2 Pages

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Catalogue excerpts

Welding fumes are complex mixtures of substances made of metal oxides, silicates and fluorides, which occur during machining procedures, such as welding, thermal cutting and related processes such as soldering, thermal spraying and flame hardening. These fumes arise if metallic materials are heated beyond boiling point, changed into gases, which then cool down in the air and condense into ultrafine particles. These particles, whose diameter is almost exclusively less than 1 m (<0.001mm!), should be categorised as very hazardous to health because they can penetrate the pulmonary alveoli when inhaling. In higher concentrations or with frequent exposure, these harmful substances can lead to immediate symptoms (vertigo, headaches, “metalworker’s fever”), chronic obstructive respiratory diseases (chronic bronchitis, asthma, lung cancer) and damage to the central nervous system (Parkinson’s disease). According to the ordinance of Hazardous Substances 98/24/EC, employees must be protected from hazardous substances and welding fumes are declared as such a substance. In Germany, the general threshold for alveolar dust is 3mg/m³ (see Technical Rules for Hazardous Substances TRGS 900). As a general rule, pollutant concentrations can occur in the breathing zone of the welder, which can exceed the guidelines many times over, when not using any ventilation measures - such as extraction systems. For high-alloyed steels, which contain more than 5 percent by weight in total of alloying elements such as chrome, nickel and manganese, even lower thresholds are compulsory for the work environment of the employee. In this case, recirculated air operation of the filtered air is strictly not permitted. Notwithstanding this principle, the air extracted in a working area may be returned there if it is sufficiently cleaned of such substances using official procedures or those recognised by Employer‘s Liability Insurance Association (e.g. safety filter H13 as an afterfilter or energy recovery using a heat exchanger) or equipment (e.g. W3-certified equipment). Information on the state of technology relating to the subject of “welding fumes” can be found in BGR 220 , TRGS 558 and TRGS 560. Problem Zambelli Technik is a metal-working SME in the Czech Republic, which enjoys a good reputation as a manufacturer of ovens and chimneys and as a supplier of the automobile industry. The export-focused company has grown strongly in the last few years and has successively expanded its production capacities as a result of this. During production, both welding fumes and abrasive dust arise as part of the procedures. The harmful substances should be extracted via a central filter system, which should preferably be installed outside the production hall. The filtered air should be returned to the hall during the heating period via a summer/winter set-up in order to use fewer resources and save heating costs. In addition welding fumes are classified as combustible, because during metal processing, i.e. when sanding, ignition sources cannot be excluded, resulting in a piping and filter fire. Conventional deflector plates and diversion offer no definite protection here, meaning that fire protection tasks must be taken into consideration during the system planning. Solution As described in the info box, approx. 99% of the particles of welding fumes are smaller than 1 m and put the highest demands on the filter medium. On one side, the filtration of ultra-fine harmful substances must be reliable in order to guarantee that the workplace and clean air concentrations are at least below the existing thresholds. However, on the other hand, moderate pressure losses should exist during long service life of the filter cartridges in order to facilitate low operating costs. Client: Zambelli Technik, spol. s.r.o, www.zambelli.de EX TR AC TION OF WELDING FUMES AND ABR ASIVE DUST WITH A CENTR AL DUST COLLEC TOR SYSTEM - CARTRIDGE FILTER Extraction of Welding Fumes and abrasive Dust with a central Dust Collector System - Cartridge Filter

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SFC COMPRESSED AIR BLAST: Patent 6, 902, 592 Venturi tube Injector nozzle Diaphragm valve Filter cartridge SFC system Since 2007, United Air Specialists provides a range of innovative filter cartridges with nanofibre technology, which satisfies these demands. They are among the best surface filters available on the market. The advantage of filter cartridges with regards to filtration efficiency and service life is rooted in an ultra-thin, synthetic fibre, which is applied to the surface of the conventional filter substrate during the production process with the help of the jet spinning procedure...

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