Purchase of Irvine’s Triconex Completed

British engineering company Siebe PLC said it has completed its previously announced $90-million acquisition of Triconex Corp.

Triconex is an Irvine-based maker of safety shut-down systems for the chemical, refining and utility industries. The company will become part of Siebe’s control-systems division. About 90 of Triconex’s 280 employees work in Orange County. The companies have said that no layoffs are anticipated.

Siebe said it completed its offer for Triconex shares Dec. 19.