The combustion air is introduced into the VAP boiler through an integral preheater, which recovers the residual heat from the final exhaust pass, prior to injection into the burner.

The flame and the hot gases heat a mono-tubular coil of varying diameter via three gas passes.

Feed water is pumped through the coil, which once heated is transformed gradually into steam. An external separator can be installed to remove any residual moisture to provide perfectly dry saturated steam, if required by the process user.

Because of the innovative design, the steam working pressure can be achieved in as little as 3 minutes from cold.

This characteristic as well as the low water volume reduces the total thermal loss and therefore helps to keep operating costs low.