Shares in filtration and environmental technology supplier Porvair have fallen even though it reported strong growth in profit in the year to November 2010. Pre-exceptional profit grew from £1.72m to £3.13m on revenues that rose 15% to £63.6m. Much of that profit improvement has come from the return to profit of the metals filtration division. Manufacturing of un-patented products has started in China. Microfiltration also edged up its operating profit contribution thanks to strong growth in nuclear and energy filtration. There is also a firm aviation order book. Net debt fell from £13.9m to £9.7m at the end of November 2011. After an unchanged interim dividend, the final dividend was edged up from 1.25p a share to 1.3p a share, taking the total for the year to 2.3p a share. The new financial year has started well with the momentum from last year carrying on into the current year. December and January revenues are higher than the same time last year.