Steam compression dryer
A dryer apparatus is disclosed comprising a container having a container inlet and outlet, a pump that is configured to motivate a first air-vapor mixture flow via the container inlet and via the container outlet, a heating device configured to heat the first air-vapor mixture, a selector with at least two states, a compressor that is configured to compress and motivate a part of the first air-vapor mixture flow as a second air-vapor mixture flow, to flow through a first heat exchanger and to flow through a second heat exchanger and a pressure reducing device that is configured to reduce the pressure of said second air-vapor mixture downstream said first heat exchanger. The selector is configured to direct most of the first air-vapor mixture to flow in a closed cycle through the container, or configured to exchange most of the first air-vapor mixture with air located outside the apparatus.
1. A method, comprising:
in an initial phase, circulating an air-vapor mixture over material to be dried in a container while heating the circulating air-vapor mixture with a heater;
in a drying phase occurring after the initial phase:
circulating the air-vapor mixture over the material to be dried in the container,
compressing a portion of said circulating air-vapor mixture,
heating said circulating air-vapor mixture by a first heat portion of said compressed portion; and
transferring a second portion of the heat originating from the compressed portion of said circulating air-vapor mixture towards a different colder fluid; and
in a cooling phase occurring after the drying phase, removing heat from the material to be dried in the container with one of exchanging the circulating air-vapor mixture surrounding said material with ambient air or transferring heat from said circulating air-vapor mixture towards said different colder fluid, further comprising,
an over drying phase which occurs between the drying phase and the cooling phase wherein said circulating air-vapor mixture surrounding said material is exchanged with ambient air which is heated by a heater.
2. The method according to claim 1 , wherein the air-vapor mixture is circulated around said container transferring heat from said circulating air-vapor mixture towards said different colder fluid where part of the vapor in said circulating air-vapor mixture condenses and the rest of the said circulating air-vapor mixture is heated by the heater and returned to the container.
3. The method according to claim 2 wherein during the Drying Phase, said circulating air-vapor mixture is heated additionally by said heater.
4. The method according to claim 1 wherein excess of said circulating air-vapor mixture which is created during the initial and/or drying phase is released to an environment.
5. The method according to claim 1 which includes means which prevents direct exposure of living beings to hot components and/or fluid.