THE price tag for air filtration company Domnick Hunter soared again last night after a second US bidder tabled an offer for the company.

County Durham-based Hunter is now valued at £242m following the approach from electrical systems manufacturer Eaton Group, which beat a revised offer from Parker Hannifin worth £232m.

Parker started the bid process at the beginning of the month, when it agreed the terms of a £215.7m takeover deal with the board of Domnick Hunter.

But its interest in the company - best known for providing air purification for fizzy drinks companies - triggered the rival approach.

The bid battle will boost the expected pay day for Hunter's chief executive, Colin Billiet, and chairman, Brian Thompson, whose combined shareholding has grown in value by £2m since the start of the month to nearly £17m.

Eaton said it wanted to create the leading supplier of filtration, separation and purification products by combining Domnick Hunter with last month's acquisition of Hayward, which has offices in Belgium and Germany.

Chief executive Alexander Cutler said: "Domnick Hunter is a strong business and will add valuable scale and market leadership to our competitive position."

Eaton has 56,000 staff and sales of £5.44bn last year, including from systems for fluid power and automotive engine air management.

Parker Hannifin, which is an industrial products group employing 50,000 staff, said it was considering its position following Eaton's announcement.

The US company wants the deal to extend its reach in European air filtration markets, while Domnick Hunter should also benefit from Parker's sales operation.

Hunter was founded in 1963 and makes filtration and purification products for a range of industries. Pharmaceuticals companies needing clean air and drinks companies requiring the purification of carbon dioxide for fizzy drinks are among its major customers.