IWA 0784 Delbag Luftfiler Air filtration slide chart 1970 Germany

Larger slide chart by IWA model 0784 in German made for the Delbag Company in the 1970’s. This can well be the successor to the 1960’s Faber Castell 8/12 Delbag circular slide rule. It is a complete redesign by mr. Rötscher so that it now fits a much easier to use slide chart. It can be used for calculation for the installation of air filters (made by Delbag) in various types of pipes as well as pipes of various materials, taking temperature and noise into account. It is in very good condition so there are only small signs of use or age from normal use, fully functioning with all parts intact. It also comes with the manual in German as well as in the original signed vinyl sleeve. It measures ca. 28 cm or ca. 11 inches wide. Check the attached video on how to work your vintage man tool : slide rule operation instructions!