A culture of product innovation has been a key to King's Lynn-based filtration specialist Porvair's soaring growth according to its chief executive.

Increased turnover and profit in the firm's annual results yesterday come on the back of 50pc growth since 2007 during which time it has generated more than �30m in cash.

The company, which still has its management team based in Norfolk, but manufactures elsewhere in the UK and around the world, recorded a 7pc increase in revenue to �68.1m with a 44pc increase in its pre-tax profit to �4.5m.

Chief executive Ben Stocks said the company had done well in its contract wins during 2011 including a big aviation contract worth �25m ($40m) over 10 years last January and at the end of the year a contract in South Korea worth up to �9m ($15m) .

'They are good contract wins,' he said. 'They keep the factories busy and they are all very reasonable margins.'

At a time of economic downturn, Mr Stocks said the company had 50pc of its business in the Americas, which had been buoyant markets.

'We happen to have been in the right markets. US and Asia are going well.'

He also said the sectors the company served had been doing well.

'Aviation has had a strong year. It continues to go well. There is a record order book for new aircraft. There is also industrial strength across the world. We have found ourselves in growing markets.'

The filtration market is a 'wide one', he said. 'Some years ago we decided to focus on aviation and energy and environmental laboratory supplies. They are all regulated. You cannot build an aircraft in your garage. All the markets are regulated so demand is not discretionary.'

'Our thought process was to find enough markets to give you scale, but not so many so that you don't know what you are talking about. We made sure they are all regulated and made sure they are growing,' he added.

Mr Stocks said all the company's departments had product development targets.

'It is just the way we run the business with a strong focus on organic growth. When you get it growing it becomes tremendously powerful.'

Porvair, which started in King's Lynn, was acquired by United Technology Corp in a management buy-out in 1982. It was fully listed on London Stock Exchange in 1992.