AIR filtration group Domnick Hunter saw half-year profits surge 16 per cent to a record high.

The company makes filtration and purification products for a range of industries.

Pre-tax profits for the six months to June 30 of £5.7m were within market expectations, after the process operations division lifted sales by 21.9 per cent. Group turnover rose 13 per cent to £67.5m.

Pharmaceuticals firms needing clean air and drink companies requiring the purification of carbon dioxide for fizzy drinks helped the process division lift operating profits by 34.7 per cent to £2.3m.

That strong demand has led the company to plan a £3m expansion of its filter manufacturing facility at Birtley, County Durham. The scheme, which should double capacity, is expected to be completed next year.

Domnick Hunter employs about 300 people at Birtley and another 1,100 staff at sites around the world.

The company said its industrial operations division was more exposed to the tough economic climate, although sales still grew 10.9 per cent, with operating profits up 3.4 per cent to £3.8m.

Work has included the development of on-board vehicle systems to protect armies from chemical and biological warfare agents.

Testing is continuing, although the firm has already signed a co-operation agreement with a US military equipment manufacturer which should lead to the supply of products.

Looking across the business, chairman Brian Thompson said the second half of the financial year had started well, with July results ahead of the same month a year earlier.

He said: "Domnick Hunter's business fundamentals remain strong and a satisfact-ory outcome for the year should be achieved and provide a firm foundation for future growth."

Shareholders will receive a half-year dividend of 4p a share, up 5.3 per cent on a year earlier.