Filtration and environmental technology group Porvair said pre-tax profit in the nine months ended August 31st was ahead of current management expectations and now anticipates the full year to be ahead of previous targets. The AIM-listed firm, which specialises in the design and manufacture of filtration and separation equipment for the aviation, energy and industrial sectors, said revenue was 13% higher in the nine months to the end of August at constant exchange rates.Trading in the Metals Filtration division improved in the third quarter after a quiet first half. As a result, revenue expectations for the full year have increased and are now expected to be broadly in line with the prior year.Revenues in the Microfiltration division revenue climbed 24% on the prior year, helped by significant activity on the POSCO, Reliance Industries and UK government contracts.It added that Chand Eisenmann Metallurgical, which it bought in June 2013, has traded satisfactorily and made its first contribution to group profits. Its integration is on track. Net debt continued to be significantly lower than the prior period. CJ