Abstract: An apparatus for connecting a vacuum pump stand with an electronic tube and including guide rails along which guide rolls mounted on the stand suction flange are displaced upon movement of the suction flange toward the electronic tube, and pivotal levers connected with the guide rails and supporting roller mounts of rollers for centering the electronic tube neck, with the suction flange including a gasket ring into which the electronic tube exhaust tube, which projects from the tube neck, extends in the upper end position of the suction flange, and with the guide rails having a variable profile such that the levers move, upon the upward displacement of the suction flange, from a position, in which the centering rollers are spaced from the electronic tube neck, into a position in which the centering rollers firmly engage the electronic tube neck, and then back into a position in which the centering rollers are again spaced from the electronic tube neck.