Evaporator unit for an inhaler having a wick structure with microchannels
An evaporator unit for an inhaler, in particular for an electronic cigarette product, comprises an electrically operable, in particular planar, heating body which has an inlet side and an outlet side, and a plurality of microchannels which each extend from the inlet side to the outlet side through the heating body, the heating body being designed to evaporate, by applying a heating voltage, liquid transferred through the microchannels. A porous and/or capillary wick structure is arranged on the inlet side of the heating body, which structure rests flat against and in contact with the heating body and covers all of the microchannels on the inlet side.
1. An evaporator unit for an inhaler, comprising:
an electrically operable heating body that has an inlet side, and an outlet side, and a plurality of microchannels that each extend from the inlet side to the outlet side through the electrically operable heating body,
wherein the electrically operable heating body is configured to evaporate, by applying a heating voltage, liquid transferred through the plurality of microchannels,
wherein a porous and/or capillary wick structure is arranged on the inlet side of the electrically operable heating body, wherein the porous and/or capillary wick structure rests flat against and in contact with the electrically operable heating body and covers all of the microchannels on the inlet side.
2. The evaporator unit according to claim 1 , wherein an average pore/capillary size of pores or capillaries in the porous and/or capillary wick structure in a contact region with the electrically operable heating body is smaller than a smallest distance of any two microchannels of the plurality of microchannels from one another.
3. The evaporator unit according to claim 1 , wherein an average pore/capillary size of pores in the porous and/or capillary wick structure in the contact region with the electrically operable heating body is smaller than a smallest inside diameter of the microchannels of the plurality of microchannels.
4. The evaporator unit according to claim 1 , wherein an average pore/capillary size in the porous and/or capillary wick structure changes monotonically as a distance from the electrically operable heating body decreases.
5. The evaporator unit according to claim 4 , wherein the average pore/capillary size in the porous and/or capillary wick structure reduces monotonically as the distance from the electrically operable heating body decreases.
6. The evaporator unit according to claim 1 , wherein the porous and/or capillary wick structure has one or more porous and/or capillary layers, pores or capillaries of which each have a constant average pore/capillary size.
7. The evaporator unit according to claim 1 , wherein the porous and/or capillary wick structure comprises a porous and/or capillary layer having a gradual decrease in the pore/capillary size in the direction towards the electrically operable heating body.
8. The evaporator unit according to claim 1 , wherein a transfer rate of the porous and/or capillary wick structure is at least as great as the maximum evaporation rate of the electrically operable heating body.
9. The evaporator unit according to claim 1 , wherein the porous and/or capillary wick structure comprises one or more materials from the following group of materials: cotton, cellulose, acetate, glass fibre fabric, glass fibre ceramic, sintered ceramic, ceramic paper, aluminosilicate paper, metal foam, metal sponge, another heat-resistant, porous and/or capillary material having a suitable transfer rate, and a combination of two or more materials of the aforementioned materials.
10. The evaporator unit according to claim 1 , wherein the porous and/or capillary wick structure has a filter layer, made of micro-glass fibre.
11. The evaporator unit according to claim 1 , wherein the porous and/or capillary wick structure has a fibre paper layer.
12. The evaporator unit according to claim 1 , wherein the porous and/or capillary wick structure has a ceramic wick layer.
13. The evaporator unit according to claim 1 , wherein the porous and/or capillary wick structure has an oil lamp wick layer.
14. The evaporator unit according to claim 1 , wherein the evaporator unit has a substrate comprising a through-opening for holding the electrically operable heating body and/or the porous and/or capillary wick structure.
15. The evaporator unit according to claim 1 , further comprising: a holding element, in the form of a printed circuit board, wherein the holding element comprises a through-opening for holding the porous and/or capillary wick structure.
16. The evaporator unit according to claim 1 , wherein a frequency and/or duty cycle of a heating voltage Uh for the electrically operable heating body is adapted to a natural vibration and/or natural frequency of vibrations of gas bubbles formed in the plurality of microchannel s.
17. The evaporator unit according to claim 16 , wherein the frequency and/or duty cycle of the heating voltage Uh is selected depending on a mixing ratio of the liquid to be evaporated.
18. The evaporator unit according to claim 1 , wherein a frequency of the heating voltage Uh is in a range between 20 Hz and 200 Hz.
19. The evaporator unit according to claim 1 , wherein a maximum heating current generated by a heating voltage Uh for the electrically operable heating body is not more than 7 A.
20. The evaporator unit according to claim 1 , further comprising:
at least one clamping element that generates a preload and is arranged and configured to clamp the electrically operable heating body onto a support.
21. The evaporator unit according to claim 20 , wherein at least two clamping elements of the at least one clamping element are provided on opposite sides of the electrically operable heating body.
22. The evaporator unit according to claim 20 , wherein the at least one clamping element has a clamping bracket which makes linear contact with the electrically operable heating body.
23. The evaporator unit according to claim 20 , wherein the at least one clamping element clamps the electrically operable heating body laterally to and in parallel with the outlet side and/or vertically onto the outlet side and/or in a corner groove of the support.
24. The evaporator unit according to claim 20 , wherein the at least one clamping element is used as an electrode for electrically contacting and supplying power to the electrically operable heating body.
25. The evaporator unit according to claim 24 , wherein at least one conductor extending through a hole in the support is provided for contacting the at least one clamping element.
26. The evaporator unit according to claim 25 , wherein the at least one conductor contacts a printed circuit board which is arranged on a side of the support and spaced apart from the support facing away from the electrically operable heating body.
27. The evaporator unit according to claim 20 , wherein the support is in the form of a printed circuit board.