US Patent 7566423 Air purification system employing particle burning

An air purification system includes a reverse flow heat exchanger, a combustion chamber and a means for heating particles configured to cause particles in air to combust in the chamber. The reverse flow heat exchanger transfers excess heat from the purified air to the incoming air to lower the amount of energy needed to combust the particles in the combustion chamber. The means for heating particles can comprise a flame or a microwave emitter. The reverse flow heat exchanger is spiral wound around the combustion chamber.