CINCINNATI—Weldun International Ltd. has developed a machine that automatically assembles air cells used in recuperators for gas engine turbines.

The machine was invented by a team of engineers led by Mike Nowak, customer proposal manager at Weldun.

Many gas turbine engines use a recuperator, or heat exchanger, to extract heat from exhaust gases and preheat the combustion air. Recuperators include a core that is commonly constructed of thin, flat sheets of metal with an angled or corrugated spacer between them. The sheets are joined into cells and sealed. They then form passages between the sheets. The cells are then stacked or rolled to form alternate air cells or hot exhaust cells. Air discharged from a compressor in the engine passes through the air cells, while hot exhaust gas flows through the alternate cells. The exhaust gas heats the sheets and spacers, and the intake air is heated by conduction from the sheets and spacers.

The Weldun assembly system ensures that each cell is produced with a uniform height and thickness. It also accurately positions each cell in the stack. Both are critical for efficient operation of the recuperator. The assembly system integrates resistance welding, gas plasma welding, bar stock feeding and cutting, multiple custom pick-and-place assemblies, a pallet conveyor, walking beam conveyor and servo drive slides.