Abstract: A mechanical seal arrangement includes a first mechanical seal with a rotating slide ring and a stationary slide ring, which define a sealing gap in between them. The mechanical seal arrangement includes a first sealing space that is filled with a sealing liquid. The first mechanical seal seals off the sealing space against a surrounding area, a first piston arrangement with a piston element and flexible wall areas that define a first piston interior space, wherein the first piston interior space is in fluid connection with the first sealing space. A piston outer surface of the piston element is in fluid connection with the surrounding area, and a first pre-stressing appliance that exerts a first preload force (F1) on the piston element of the first piston arrangement.

Abstract: The invention relates to a mechanical seal arrangement, comprising: a first mechanical seal (10) with a rotating slide ring (11) and a stationary slide ring (12), which define a sealing gap (13) in between them, a first sealing space (14) that is filled with a sealing liquid, wherein the first mechanical seal (10) seals off the sealing space (14) against a surrounding area (6), a first piston arrangement (15) with a piston element (16) and flexible wall areas that define a first piston interior space (160), wherein the first piston interior space (160) is in fluid connection with the first sealing space (14), wherein a piston outer surface of the piston element (16) is in fluid connection with the surrounding area (6), and a first pre-stressing appliance (19) that exerts a first preload force (F1) on the piston element (16) of the first piston arrangement (15).

Abstract: The present invention refers to a wellbore conveyor device for conveying a medium (9) from a wellbore (8), comprising: a drive (2); a pump (3); a shaft (4) which connects the drive (2) to the pump (3); a mechanical seal unit (5), comprising a mechanical seal (50) with a rotating seal ring (51) and a stationary seal ring (52), the mechanical seal (50) sealing on the shaft (4); and an independent supply means (6) which supplies the mechanical seal (50) with a barrier medium, the independent supply means (6), the drive (2), the pump (3), the shaft (4) and the mechanical seal unit (5) forming a compact conveying unit which is fully submersible in the wellbore.

Abstract: A sealing system in a ball valve is designed with a bellows which carries a sliding packing ring on the side of the valve housing and presses against a sliding packing ring on the side of the pivot shaft. The bellows is protected by a guard ring. The ball valve has a shaft coupled to a cap through a releasable locking device.