Fluid lock

A fluid lock for permitting transiting an object between different fluid pressures through a transiting hole in a wall separating a higher fluid pressure side from a lower fluid pressure side on opposite sides of said wall, comprising

• higher and lower fluid pressure doors,
• connecting means operatively connecting said doors to the wall respectively on the higher and lower pressure sides for permitting relative movement of each door between an open position for permitting transiting through the hole from one to the other pressure side and a closed position for sealing said hole,
• transiting container means formed between the doors in closed position having an inner surface closely form fitting the transiting object for minimizing the loss of fluid between the sides during transiting the object through the hole, said doors having inner faces facing in closed position, being spaced apart at least the thickness of the transiting object, so the object can be located between the door innerfaces with both doors in closed and sealed positions, and
• two windows, one in each door in front of the transiting object so that the transiting object, if a human being, can simultaneously see either pressure side when both doors are in closed position.