Apparatus for the treatment and purification of process flows in installations for generating gas through electrolysis, in particular in installations for generating hydrogen and oxygen; apparatus for the treatment, purification and heating of water in an installation for generating gas through electrolysis; apparatus for the separation of oxygen from electrolysis water, in particular containers with packing or bulging installations; apparatus for the separation of hydrogen from electrolysis water; apparatus for the purification of gaseous oxygen and gaseous hydrogen; apparatus for drying gases, in particular hydrogen and oxygen; apparatus for the temperature control of electrolysis water; apparatus for using waste heat of electrolysis; ventilation and air-conditioning installations in installations for generating gases through electrolysis, in particular in installations for generating hydrogen and oxygen; installation unit for an installation for generating gas through electrolysis comprising one or more of the aforesaid apparatus or installations; all the aforementioned goods being solely intended for operators of industrial gas installations; none of the aforementioned goods being used in connection with the mobility and transport of individuals.