Television projection system having frame with integral cooling

A device for projecting television pictures onto a projection screen by using three television picture tubes arranged in the proximity of each other, each comprising a display window having a display screen provided on the inside thereof and a light transmissive element arranged at a distance in front of the display window, which element together with the display window bounds a flow space for passing through a coolant, the flow spaces being in open communication with a liquid circuit for removing the heated coolant from and applying cooled liquid to the flow spaces, the liquid circuit comprising a first duct extending below the television picture tubes, which duct is in direct communication via passages with the lower ends of the flow spaces, and a second duct extending above the television picture tubes, which duct is in direct communication via passages with the upper ends of the flow spaces, whilst the first and the second duct are connected via at least one connection duct extending along the outer end of the assembly constituted by the three television picture tubes, characterized in that the first and the second duct at their both ends are connected by a connection duct, and further characterized in that the first and the second duct and the connection duct are passages in a frame supporting the television picture tubes.