Vessel and methods for calibrating, cleaning or removing an implement located in such a vessel or inserting an implement into such a vessel

A method for calibrating a measuring or detecting instrument located in a fluid receiving space inside a vessel, the method comprising:

• actuating an enclosure from an open position, in which the enclosure does not enclose a closed space around the instrument, to a closed position, in which the enclosure forms a fluid tight or at least essentially fluid tight casing that encloses a closed space around the instrument so as to prevent fluid in the fluid receiving space outside said closed space from flowing into the closed space;
• discharging fluid out of the closed space;
• supplying calibration fluid with known characteristics into the closed space;
• calibrating the instrument based on one or several measuring or detecting operations performed by the instrument on the calibration fluid;
• and
• actuating the enclosure from the closed position to the open position so as to allow fluid in the fluid receiving space to come into contact with the instrument.

A method for cleaning an implement located in a fluid receiving space inside a vessel, the method comprising:

• actuating an enclosure from an open position, in which the enclosure does not enclose a closed space around the implement, to a closed position, in which the enclosure forms a fluid tight or at least essentially fluid tight casing that encloses a closed space around the implement so as to prevent fluid in the fluid receiving space outside said closed space from flowing into the closed space;
• discharging fluid out of the closed space;
• supplying flushing fluid into the closed space and discharging the flushing fluid out of the closed space a suitable number of times or for a suitable period of time;
• and
• actuating the enclosure from the closed position to the open position so as to allow fluid in the fluid receiving space to come into contact with the implement.

A method for removing an implement from or inserting an implement into a fluid receiving space inside a vessel, the method comprising:

• actuating an enclosure from an open position, in which the enclosure does not enclose a closed space inside the fluid receiving space, to a closed position, in which the enclosure forms a fluid tight or at least essentially fluid tight casing that encloses a closed space inside the fluid receiving space so as to prevent fluid in the fluid receiving space outside said closed space from flowing into the closed space;
• gaining access to the closed space by uncovering an access opening provided in a wall of the fluid receiving space;
• and
• removing the implement from or inserting the implement into the closed space inside the fluid receiving space via the access opening.