The Akyurek centrifugal fan type ACF is a medium pressure fan having backward curved steel blades manufactured in steel plate. The impeller is self-cleaning and dynamically balanced. The spiral housing is made of welded steel plate. The fans are supplied with a direct coupled 1450 rpm flange motor. The larger models, ACF620, 625 and 630 are supplied with motor frame and built-in Varifan on the suction side. The ACF fans are as standard equipped with trottle valves and can be supplied with the specially developed VARIFAN (see drawing) which is made of adjustable guide plates placed as a rosette at the intake. It regulates the air volume and reduces the energy consumption with lowered capacity.