Renewal of the pure space cover on production conditions in an electronics enterprise

In an electronics enterprise for circuits in Dresden the task was located to renew the complete filter cover with filters from the year of construction 1986. It acted here around a positive pressure cover, which was converted if possible without disturbances of the production flow by local work tents. WISAG building and industrial service Dresden realized this complicated task with very good success. The filter cover with H14-Filtern had reached after approximately 24 years continuous use a pressure loss of approx. 250 Pa at a displacement speed from approx. 0.30 to 0.35 m/s. Remarkably the fact that the filters had not achieved the theoretical service life end after this long utilization period yet of 500 Pa, is what again the user a very accurate pure space regime certified. The cover raster had been established in the module 1200 x 1200 mm and/or 1200 x 2400 mm with large gate widths between 100 to 160 mm with a light room height of 4,2 m. Old pure space walls in the strength 80 mm had been partly replaced by modern electronics walls with the strength 50 mm. The ventilation system was a plant solution with primary air (outside air 10 to 20%) and Sekund�rluft (circulating air 80 to 90%) and a printing cover with positive pressure. This system was realized later only rarely, since the cover must be implemented to the pure area absolutely and a solution with filter fan units was not available at this time yet. The filters and filter framework had been sealed here with gasket and epoxy resin. For the change only small ranges could be made available for technical reasons. Therefore again a printing cover in a distance had from 0,50 m to the existing cover (height of 3.70 m) to be realized. It the knot grid ceiling Model 1200 mm x 1200 mm with gasket of WISAG selected, there by the existing walls with different situation to the oh raster a special wall junction with special raster, special knot and special filters were necessary. One worked with the basic principle of the 3fachen sealing � silicone joint on print page, gasket and silicone joint on pure space side �. Each range was bulkheaded with new bulkheads in the pressure chamber. During adjustment the existing supply air ducts with control valves were used to new adjustment on approx. 60 Pa filter initial printing. The client demanded the filters U15 for the new suspended matter filters after EN 1822 with boron-free filter paper, so that the today's demands and those of the next years for customized circuits can be fulfilled. In addition all filters received a grasp protection on raw air and pure downstream face. With these precautionary measures and the circumstance of the long service life of more than 20 years, specified above, the risk of a seal of the filters with silicone seemed justified. A building expansion joint in the cover with an oh measure of 120 mm was additional Herausforderung.Die of results of the new filter cover can after 3 realized sections to be seen be able. The category of purity according to ISO 14644 was with only 12 hours of free time of blast � RK remainder � the class 3 and � in operation � after some weeks likewise the class 3. the filter bars is now only 60 mm broad. A lighting with Teardrop lights and the new situation of the filter cover more near to the process place as well as the bright filter surface were likewise positive side effects. The operating cost for the driving power can be lowered for complete RLT ranges around approx. 30%. A good preparation, beginning with a laser air passage, the delivery complete of the assembly material and control before commencement of construction, an assembly in the multi-shift operation and immediate IQ-control, together with that AG, were the condition for a very short construction period in the subranges.

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