It concerns the invention of a pressure vessel (VP) which can be assembled from individual parts, and basically comprises: a plurality of wall modules (MP), at least one connection module (MC) for pipes or sensors, and closing modules (MF) that can be chosen from: have equal configuration and have different configurations. All of the modules have bores (105) distributed radially on their flat surfaces (101) and these bores (105) are distributed between a hollow drill (1051) with a seat (1151) and a torque screw bored (1052) (106) inserted therein attach a module to another adjacent module, with a sealing ring (104) therebetween.