Internormen Filters Private Ltd. Supplies Vertical Mounted Pressure Change Over Filter. Internormen Filters Private Ltd. Is an ISO 9001: 2000 recognised company manufacturing a wide range of filters for hydraulic and lubricating fluids and contamination monitoring system. The Vertical Mounted Pressure Change Over Filter of the series DU 63 model is suitable for a working pressure up to 32 bar and can also be installed as suction-filters. The Vertical Mounted Pressure Change Over Filter consist of star-shaped, pleated filter material and can be used for all petroleum based fluids, HW-emulsions, most synthetic hydraulic fluids and lubrication oils.