Indirect Heat Exchanger

The baking industry have many types of baking ovens for varied purposes to achieve different types of bake.

The baking industry have many types of baking ovens for varied purposes to achieve different types of bake. Baking oven types can be divided between direct and indirect. Indirect baking ovens rely on a heat exchanger to distribute the heat in the oven and have no product of combustion in contact with the bake product which is a benefit with regards to health and safety.

Baker Perkins, Spooner Vicars, Meincke, Imaforni and other manufacturers have adopted indirect heating ovens for many years.

A blue chip company got in contact with EnerTherm Engineering with a reliability problem with their fleet of oven making biscuit. Each oven has 3 to 8 indirect heat exchangers and the reliability of each heat exchanger is a major concerns which has impact on running cost and down time. Each indirect heat exchanger last for 12-18 months.

EnerTherm Engineering investigated the problem by simulating current design and evaluated the root cause of failure. Air flow and heat distribution in the heat exchanger causes thermal stress and leads to heat exchanger tube failure.

EnerTherm Engineering have designed a new indirect heat exchanger using Computation Fluid Dynamics and FEA stress analysis, to ensure minimal thermal induced stress onto the tube header.

The overall efficiency of the heat transfer through the indirect heat exchanger was increased by 30%. The thermal induced stress was reduced to nil. The new unit will be built in the next few months and installed.