US Patent 10149497 E-cigarette personal vaporizer

An e-cigarette PV that includes an air pressure valve or device so that excess air can escape from an e-liquid reservoir in the PV when that reservoir is being filled under pressure with e-liquid from a parent reservoir. The valve or device is a barrier made of an air-porous material, such as a sintered polymer or metal, coated with or otherwise including a barrier or layer of an air-porous substance that is not porous to e-liquid, such as an oleophobic material or a hydrophobic or super-hydrophobic material. The oleophobic material is one of: sintered phosphor bronze, sintered stainless steel and sintered PU plastic.