Optional manhole access for bobbin wound filters in lateral or top position with nominal diameters of 500 and 600 mm. Designed to comply with DIN standard 19605 and to facilitate access in and out of the filter during maintenance work. Manholes are in fibreglass reinforced polyester in the form of a flange with concave lid and can only be integrated into the filter at the factory or by a specialist. The manhole options are available with the following bobbin wound filter diameters: Manhole DN500* Filters from Ø 1200 mm to Ø 3000 mm. Manhole DN600* Filters from Ø 1800 to Ø 3000.