Heat exchanger

Claim 1

A heat exchanger used in an automotive vehicle comprising: upper and lower tanks, a plurality of conduits extending between and in communication with said upper and lower tanks, and a plurality of radiating fins provided in spaces between said conduits; wherein said upper tank comprises: a partition wall, disposed in said upper tank, for dividing said upper tank into upper and lower rooms, means for maintaining the pressure in said upper room at the pressure of the atmosphere surrounding said heat exchanger, tubular means, connected to said lower room to communicate said lower room with said atmosphere, for supplying cooling fluid into said lower room therethrough, a cap removably mounted on the upper end of said tubular means, a negative pressure valve, positioned on said partition wall apart from said tubular means, for passing air contained in said supplied cooling fluid therethrough into said upper room as the level of said cooling fluid goes up in said lower room, means, provided in said tubular means, for passing said cooling fluid into said upper room from said tubular means to reserve said cooling fluid in said upper room; and a positive pressure valve removably installed in said tubular means, for opening itself to allow escape of said cooling fluid into said upper room through said cooling fluid passing means when the pressure in said lower room exceeds a first predetermined value, said negative pressure valve being operative to allow flow through itself of said reserved cooling fluid in said upper room into said lower room when the pressure in the lower room becomes lower than a second predetermined value.