Rotork the manufacturer of electric, pneumatic and hydraulic valve actuators, is to buy a US designer and manufacturer of nuclear actuators.Rotork is paying $7.8m in cash for Ralph A. Hiller, a 60-year old company based in Pittsburgh, Pennsylvania. Around $1.3m of the cash consideration will be deferred and will be paid over the next 19 months.In the year to end-September 2009 Hiller had a turnover of $14.6m and made a profit before tax of $0.42m."Hiller will sit within Rotork's Fluid Systems division and provide the group with a range of additional complementary nuclear products which will be sold through existing sales channels and Rotork's worldwide network of sales offices," said Rotork's chief executive, Peter France.