Patent Number: 
Section: claims

1. A device for sealing a tube in an opening located in a component, comprising: a hydraulically driven pressure element being in operative connection with the tube for pressing the tube against the component, said pressure element producing a contact pressure power between the tube and the component, and said contact pressure power containing a hydraulic power factor, said pressure element having a pressure part producing a force and a disk spring producing a preloading force, said disk spring disposed between said pressure part and the component. 2. The device according to  claim 1 , including: claim 1 a hydraulic line connected to said hydraulically driven pressure element; and  a pressure gauge connected to said hydraulic line for measuring the preloading force of said disk spring. 3. A device for sealing a lance shaft in a nozzle connected to a cover of a reactor pressure vessel, comprising: a hydraulically driven pressure element being in operative connection with the lance shaft for pressing the lance shaft against the cover of the reactor pressure vessel, said pressure element producing a contact pressure power between the lance shaft and the cover of the reactor pressure vessel, and said contact pressure power containing a hydraulic power factor, said pressure element having a pressure part producing a force and a disk spring producing a preloading force, said disk spring disposed between said pressure part and the cover of the reactor pressure vessel. 4. The device according to  claim 3 , including: claim 3 a hydraulic line connected to said hydraulically driven pressure element; and  a pressure gauge connected to said hydraulic line for measuring the preloading force of said disk spring.