Abstract: The invention discloses a pressure electrolyzer comprising a pressure vessel (2) and an electrolytic-cell block (3) arranged in the pressure vessel (2) and containing a plurality of electrolytic cells (4) combined in the form of a stack. The electrolytic cells (4) in each case contain anodes (11) and cathodes (12), and an electrolyte-circuit system is provided for supplying an anolyte to the anodes (11) and for supplying a catholyte to the cathodes (12), and wherein the electrolytic-cell block (3) comprises a housing (5) which is sealed relative to the interior of the pressure vessel (2). The invention provides that the housing (5) of the electrolytic-cell block (3), together with the pressure vessel (2), forms at least two chambers (7, 8) separated from each other, which constitute a part of the electrolyte-circuit system and which are defined relative to the electrolytic cells (4) by the housing (5) and relative to the atmosphere by the pressure vessel (2).

Abstract: A pressure electrolyzer having a pressure reservoir, an electrolytic cell block containing a number of electrolytic cells and positioned in the pressure reservoir, the electrolytic cells each containing anodes and cathodes, and an electrolyte circulatory system for supplying electrolyte to the anodes and cathodes. The circulatory system includes an oxygen separator operative to separate gaseous oxygen formed during operation of the pressure electrolyzer and a hydrogen separator operative to separate gaseous hydrogen formed during operation of the pressure electrolyzer, and a store of an inert gas, to inert the pressure electrolyzer when it is switched off. The store of inert gas is supplied to the oxygen separator. The electrolyte circulatory system further includes a connecting line arranged so that a part of the electrolyte can be pushed out of the hydrogen separator when the inert gas is applied to the oxygen separator so as to displace the gaseous hydrogen.