Halma reported a 6% rise in first half pre-tax profit to £69m, driven by a strong performance in the US and growth in its process safety, infrastructure safety and medical divisions.The safety, health and environmental technology group said revenue increased 2% to £340.9m, offset by advert currency translation due to the strength of sterling. The group's results were also weighed down by lower profit in the environmental and analysis business.In the first half, the company spent £87m on the acquisition of Plasticspritzerei AG, Plasticspritzerei AG and Rohrback Cosasco Systems.The firm sold Monitor Elevator Product, a business within the infrastructure safety sector, for a consideration of $6 from which a gain of £1m before tax was derived.Net debt rose to £136.3m from £109.8m.Halma raised its interim dividend by 7% to 4.65p as it gave a positive outlook for the second half."Halma has made strong progress in the first half, achieving record revenue and profit despite the varied market conditions and adverse currency translation impact," chief executive Andrew Williams."We are particularly pleased to report organic constant currency revenue growth across each of our regions. Order intake since the period end has continued to be ahead of revenue and order intake last year. Halma remains on track to make further progress in the second half of the year in line with our expectations."