Oxygenator having an improved heat exchanger

In a blood oxygenator having an integral heat exchanger for regulating the temperature of the blood flowing in an extracorporeal blood circuit, comprising a gas exchanger section comprised of a first housing;

• a bundle of a multiplicity of hollow fibers for gas exchange, said hollow fibers arranged side by side within said first housing;
• first and second walls liquid-tightly carrying said hollow fibers at the end portions of said hollow fibers, with the end portions of said hollow fibers being left open, said first and second walls defining a gas exchange chamber with the inner wall of said first housing and outer wall surfaces of said hollow fibers;
• oxygen inlet and outlet means communicating with said gas exchange chamber;
• and a first blood circulation opening communicating with an interstitial space of said hollow fibers externally of said first wall;
• the improvement comprising a heat exchanger section comprising:
• (a) a second housing defining a heat exchanger chamber with the second wall of said gas exchanger section such that said second housing is in fluid communication with the interior of said hollow fibers;
• (b) heat transfer fluid conduit means for carrying heat exchange fluid, said conduit means including a conduit having a plurality of rib members about its circumference, each of said rib members being parallel to each other, said conduit being wrapped in a conical helix defining an interior and exterior of a cone and said conduit having flattened surfaces on the interior and exterior of the cone defined by said conduit, said flattened surfaces such that if the diameter of round conduit is equal to x, the minimum diameter across the flats of said conduit is (0.74.+-.0.02)X;
• (c) heat exchanger section core means within said second housing, said core means being conical in shape and being configured with an exterior surface which defines a helical recess region including flattened surfaces conforming to the helix of said flattened conduit such that said conduit may be tightly wrapped about said core thereby defining a low volume channel through which blood may pass between the recess regions and adjacent conduit;
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• (d) said second housing having an internal wall being conical in shape and configured such that its inner surface defines a helical recess region including flattened surfaces conforming to the helix of said flattened conduit such that when said core means and conduit are positioned therewithin a low volume channel is defined between said housing recess regions and said conduit through which blood may pass from a blood inlet means in fluid communication with the interior of said second housing to the interior of said hollow fibers.

In a blood oxygenator having an integral heat exchanger for regulating the blood temperature, said oxygenator including a gas exchanger section comprising a hollow fiber oxygenator in which the blood inlet to the fiber oxygenator is joined in fluid tight relation to a heat exchanger section, the improvement comprising a heat exchanger section comprising:

• (a) a housing defining a heat exchanger chamber with the blood inlet of the fiber oxygenator such that said chamber is in fluid communication with the interior of said hollow fibers, said housing further including blood inlet means for carrying blood to be oxygenated therewithin;
• (b) heat transfer fluid conduit means for carrying heat exchange fluid, said conduit means including a conduit having a plurality of concentric rib members about its circumference, said conduit being wrapped in a conical helix defining an interior and exterior of a cone, the conduit having flattened opposing surfaces on the interior and exterior of the cone defined by said helix;
• (c) heat exchanger core means within said housing, said core means being conical in shape and being configured having an exterior surface which defines a helical recess region conforming to the helix of said flattened conduit so as to minimize fluid volume therebetween;
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• (d) said housing having an internal wall being conical in shape and being configured such that its inner surface defines a helical recess region conforming to the helix of the flattened conduit such that said conduit is tightly wrapped between said core means and housing to thereby minimize the volume of the channels through which blood may pass between the recess regions and conduit.