US Patent 10111466 Electronic cigarette

An electronic cigarette has a vaporizer to produce vapor to be delivered to its mouth end. The vaporizer includes a tube having inlet and outlet ends. A porous matrix containing a vaporizable liquid, extends around the tube. Wicking fibers extend through side openings in the tube and are configured to wick the vaporizable liquid from the porous matrix into the tube, and electrical heater coil is powered by a battery to vaporize liquid on the wicking fibers in the tube, so that vapor is supplied along the tube end when the user draws on mouth end. An airflow restrictor is provided to accelerate the flow of air along the tube to the heater coil.