Valve, comprehensive: - a valve housing having an inlet port, an outlet port, and a passageway connecting the inlet port to the outlet port, - a valve assembly comprising a ceramic valve body disc having at least one valve body opening and being movable relative to a ceramic valve seat disc having at least one valve seat opening and blocking the through passage in a first relative position of the valve body disc to the valve seat disc and opening the through passage in a second relative position of the valve body disc to the valve seat disc, - a second inlet or outlet port from which a second passageway extends, - a second valve assembly comprising a second ceramic valve body disc having at least one valve body opening, which is movable relative to a second ceramic valve seat disc having at least one valve seat opening and, in a first relative position of the valve body disc to the valve seat disc, blocks fluid communication between the second through passage and the through passage and, in a second relative position of the valve body disc to the valve seat disc, opens fluid communication between the second through passage and the through passage, wherein the valve body disc is mechanically coupled to a gear that engages a gear pinion for transmitting torque from the gear pinion to the gear and the valve body disc, and the gear is disposed within the valve housing and the gear pinion is mechanically coupled to an actuator disposed outside the valve housing, wherein the valve body disc is rotatably supported about an axis of rotation that is parallel to a longitudinal axis of the passageway, and the second valve body disc is mechanically coupled to a second gear that is engaged with the gear pinion for transmitting torque from the gear pinion to the second gear and the valve body disc, and the second gear is disposed within the valve housing, characterized in that the inlet or outlet ports are interconnected by first and second passage channels (370a,b) extending along two longitudinal axes (371a,b) which are T-shaped relative to each other and through which the fluid can flow through the valve, the passage channels (370a,b) meeting at a connection point. - a valve housing having an inlet port, an outlet port, and a passageway connecting the inlet port to the outlet port, - a valve assembly comprising a ceramic valve body disc having at least one valve body opening and being movable relative to a ceramic valve seat disc having at least one valve seat opening and blocking the through passage in a first relative position of the valve body disc to the valve seat disc and opening the through passage in a second relative position of the valve body disc to the valve seat disc, - a second inlet or outlet port from which a second passageway extends, - a second valve assembly comprising a second ceramic valve body disc having at least one valve body opening, which is movable relative to a second ceramic valve seat disc having at least one valve seat opening and, in a first relative position of the valve body disc to the valve seat disc, blocks fluid communication between the second through passage and the through passage and, in a second relative position of the valve body disc to the valve seat disc, opens fluid communication between the second through passage and the through passage, wherein the valve body disc is mechanically coupled to a gear that engages a gear pinion for transmitting torque from the gear pinion to the gear and the valve body disc, and the gear is disposed within the valve housing and the gear pinion is mechanically coupled to an actuator disposed outside the valve housing, wherein the valve body disc is rotatably supported about an axis of rotation that is parallel to a longitudinal axis of the passageway, and the second valve body disc is mechanically coupled to a second gear that is engaged with the gear pinion for transmitting torque from the gear pinion to the second gear and the valve body disc, and the second gear is disposed within the valve housing, characterized in that the inlet or outlet ports are interconnected by first and second passage channels (370a,b) extending along two longitudinal axes (371a,b) which are T-shaped relative to each other and through which the fluid can flow through the valve, the passage channels (370a,b) meeting at a connection point.