Abstract: Gas condenser (2) arranged to condense gas/vapour (4) evaporating from a volatile liquid (6) being stored, for example, in a storage tank. The gas/vapour (4) is conducted into a gas chamber (16) provided with openings, possibly also nozzles (76), the gas chamber (16) being placed in a surrounding housing (36). Thereafter, the gas/vapour (4) is sucked into at least one venturi section (62, 64), wherein the liquid (6), for example, is flowing with a static underpressure relative to the inflowing gas/vapour (4). Via at least one expansion section (88, 90), a mixture (92) of gas/vapour (bubbles) (4) and liquid (6) flows onward to a condensing chamber (98), through which the static pressure of the liquid (6) increases and the gas/vapour (4) is condensed, after which the mixture (92) is conducted back to, for example, the storage tank.