chamber 14 formed of a bed of rigid beads 15 in a cylinder 16 a diverter 17 a defoamer 18 a heat exchanger 21 having a core 22 supported by rings 23 therein and a graduated reservoir 24 ejector 12 is essentially a mixing chamber and bubble pump having side walls 25 which are concave inward oxygen is supplied through conduit 26 to the oxygenator from an outside source not shown entering diffuser 13 diffuser head 27 shown in detail in fig2 is constructed of a close weave fabric 28 having openings of uniform size secured to a retaining ring 29 attached to the top of diffuser 13 the fabric may be dacron a registered trademark or other suitable material having relatively uniform openings approximately 40 microns across retaining ring 29 may be any non corrosive relatively rigid material such as lucite a dupont trademark or stainless steel since a relatively inexpensive disposable yet sturdy structure is contemplated a rigid plastic retaining ring is preferred of course the oxygenator of this invention is not limited to being disposable and the materials used may vary due to different requirements of the users referring again to fig1 oxygen depleted venous blood enters the ejector through conduits 31 note that there are two inputs which enter the bottom of the ejector at an angle in order to provide a gentle swirling motion the ejector is normally full of blood and at the beginning of an operation must be primed with blood or a saline solution in the normal manner oxygen is released from diffuser head 27 forming bubbles of substantially uniform size in the blood as will be seen later.