Vaporiser consisting of a tube (10), surrounded by a heater (14), which seats a vaporiser body (16) in the form of a pot whose base faces a valve body (26), and its associated closure element (34) which is located in a central recess in the base. The valve body is attached in a sealed, but flexible, manner to a flange (12) of tube (10) and has a central bore which is supplied with fluid through a tube (32). USE - Liquid vaporiser for semi-conductor manufacture ADVANTAGE - Accurate dosing is possible in a short process cycle.