Well tool device for opening and closing a fluid bore in a well

A well tool device comprising:

• a housing having an axial through bore;
• a sleeve section releasably connected to the housing in the axial through bore, wherein the sleeve section comprises an axial bore;
• a frangible disc provided in the axial bore of the sleeve section in sealing engagement with the sleeve section;
• and
• a first supporting sleeve fixed to the housing in the axial through bore and a second supporting sleeve provided radially inside of, and releasably connected to, the first supporting sleeve,
• wherein the sleeve section is axially displaceable within the axial through bore between a first position and a second position;
• wherein the housing comprises an axial bypass fluid passage provided axially between a first location above the sleeve section and a second location below the sleeve section when the sleeve section is in the first position, wherein the axial bypass fluid passage is provided radially between the sleeve section and the housing when the sleeve section is in the first position;
• wherein the well tool device comprises a sealing device provided radially between the sleeve section and the housing when the sleeve section is in the second position;
• and
• wherein the first supporting sleeve comprises an upwardly facing surface configured to support a lower end of the sleeve section when the sleeve section is in the second position.