The casing is subjected to high internal pressure and can be closed with a cover. Near the cover it has at least one connecting flange for a connector. The cover is removable. The casing (1) has a thickening (6) in the region of the connector (3, 4) at least for the high pressure line, to receive the connecting flange of the connector. The devices for fixing the cover are wholly or partly in the region of the thickening. The connecting flanges (2) and/or the connector fixing devices are on the greater dia. and partly in the same plane as one of the fixing devices for the cover.
