operating principle

The blue line marks the fresh air that goes in at the bottom of the lotus cap. 
On the center of the hotplate (where the heat is applied) the fresh air gets into hot air. Its a closed system - so no butane gas gets inhaled.

The hot air reflected by the red line flows through the herb-chamber and starts the evaporating process.

With the Lotus, you can control the temperature and thus also the density of the clouds with the draw speed.
The slower the draw speed - the denser the clouds