Fluid transfer device and closed medicine transfer system

A fluid transfer device for use in medical and/or pharmacological applications, comprising a first adapter unit comprising a first sealing element and a second adapter unit comprising a second sealing element, wherein the first adapter unit and the second adapter unit are configured to provide a fluid connection between the first adapter unit and the second adapter unit in a connected state and to prevent a fluid transfer out of the first adapter unit and the second adapter unit in an unconnected or separated state, wherein

• the first adapter unit and the second adapter unit are formed to establish the fluid connection between the first adapter unit and the second adapter unit by a combined pressing movement toward each other and rotational movement with respect to each other only after adjusting a constant or defined pressure, which the first sealing element and the second sealing element apply against each other, wherein
• the first adapter unit and the second adapter unit are configured to assume, in addition to the connected state and the unconnected or separated state, a transfer state in which the first adapter unit and the second adapter unit are attached to each other and the first sealing element and the second sealing element are in contact with each other and apply the constant or defined pressure against each other, and a fluid connection is not yet provided between the first adapter unit and the second adapter unit, and wherein
• the first adapter unit and the second adapter unit are configured to be transferred from the unconnected or separated state to the transfer state by pressing on each other and rotating relative to each other by a first predetermined angle, and to be transferred from the transfer state to the connected state by continued rotation by a second predetermined angle.