Abstract: The invention relates to a plate heat exchanger with a plate package (1) including a plurality of heat exchanger plates, which are stacked onto each other. The heat exchanger plates form first plate interspaces for a first medium and second plate interspaces for a second medium. A casing encloses the plate package and comprises a circular cylindrical outer envelope (6) and two end plate members (7, 8). The outer envelope defines the center axis (x) through the two end plate members. A first inlet (11) and a first outlet (12) convey the first medium into and out from the plate heat exchanger through a respective end plate member. A second inlet (21) and a second outlet (22) convey the second medium into and out from the plate heat exchanger. The plate package has a space which is disposed inside the first inlet and the first outlet.