Heat exchanger for physiological fluids

• US 4,878,537 A
• Filed: 05/26/1987
• Issued: 11/07/1989
• Est. Priority Date: 05/27/1986
• Status: Expired due to Term

• Current Assignee: Smiths Medical ASD, Inc. (Smiths Group International Holdings Ltd.)
• Original Assignee: Level 1 Technologies Incorporated
• Inventors: Verkaart, Wesley H.
• Primary Examiner(s): BENNETT, HENRY A
• Application Number:
  US07/053,637
• Time in Patent Office: 896 Days
• Field of Search: 62/259.3, 165/156, 165/159, 165/163, 165/164, 165/154, 165/46, 165/67, 604/113, 128/399
• US Class Current: 165/156
• CPC Class Codes: A61M 2205/366 by liquid heat exchangers
• CPC Class Codes: A61M 5/44 having means for cooling or heating the devices or media
• CPC Class Codes: F28D 7/024 the conduits of only one medium being helically coiled tubes, the coils having a cylindrical configuration
• CPC Class Codes: F28D 7/106 consisting of two coaxial conduits or modules of two coaxial conduits
• CPC Class Codes: F28F 9/02 Header boxes; End plates

Abstract

A heat exchanger preferably for use in heating physiological fluids includes an inner conduit, an outer conduit, and end caps which seal the outer conduit to the inner conduit to form a flow channel. The inner conduit is preferably of aluminum and the outer conduit and end caps are of an elastomeric material. The end caps are designed to tightly engage the inner conduit and to be solvent bonded to the outer conduit. When the inner conduit elongates because of thermal expansion, the outer conduit elastically deforms so that there is no relative movement between the end cap and the inner conduit. This preserves sterility during temperature variation.

Claims

1. A heat exchanger capable of maintaining sterility during temperature variation comprising an inner conduit, an outer conduit partially covering said inner conduit and forming a fluid flow channel between an outer surface of said inner conduit and an inner surface of said outer conduit, and end cap means for securing and fluid sealing one end of said outer conduit and for communicating a first fluid with said channel, wherein said inner conduit has a thermal coefficient of expansion larger than that of said outer conduit and said outer conduit is elastic for at least partially accommodating expansion or contraction of said inner conduit, and wherein said end cap means is elastic for at least partially accommodating expansion or contraction of said inner conduit and comprises a first hollow portion cemented to said one end of said outer conduit and a second hollow portion having a hoop strength adequate to tightly grip said outer surface of said inner conduit to provide a pressure tight seal between said second hollow portion and said inner conduit and to provide a location of said pressure tight seal which remains substantially fixed with respect to said inner conduit during normal thermal expansion or contraction of said inner conduit.

2. A heat exchanger according to claim 1 wherein said outer conduit is made of an elastic plastic and said inner conduit is made of a metal.

3. A heat exchanger according to claim 2 wherein said metal is aluminum.

4. A heat exchanger according to claim 2 wherein at least a part of the exterior surface of said inner conduit is configured to provide a helical said fluid flow channel.

5. A heat exchanger according to claim 2 wherein said end cap means is made of elastic plastic.

6. A heat exchanger according to claim 5 wherein said end cap means comprises a first end cap at a first end of said outer conduit and a second end cap at an opposed end of said outer conduit.

7. A heat exchanger according to claim 1 wherein said second hollow portion comprises a protuberance extending radially inwardly and engaging said inner conduit.

8. A heat exchanger according to claim 2 wherein said inner and outer conduits are cylindrical.

9. A heat exchanger according to claim 7 wherein said inner conduit extends beyond said end cap means for providing a fluid connection to said inner conduit.

10. An end cap for sealing an end of an outer conduit to an inner conduit comprising a first hollow portion for receiving said end of an outer conduit and having an inner wall for engaging an outer wall portion of said end of an outer conduit, a second hollow portion for receiving said inner conduit, said second hollow portion having an inner wall for engaging an outer wall of said inner conduit, said second hollow portion having a protuberance extending radially inwardly for tightly engaging said outer surface of said inner conduit wherein said first and second hollow portions and said protuberance are integrally formed of elastomeric material.

11. An end cap according to claim 10 wherein said elastomeric material is polyvinylchloride.

12. A heat exchanger comprising an inner conduit, an outer conduit partially covering said inner conduit to form a flow channel between said inner and outer conduits, and two end caps, each of said end caps comprising a first hollow portion having an inner wall cemented to a portion of the outer wall of said outer conduit and a second portion comprising a second hollow portion tightly and sealingly engaging a portion of the outer wall of said inner conduit and a protuberance engaging said outer surface of said inner conduit, wherein said end caps are made of elastic material and wherein said first and second hollow portions and said protuberance are integrally formed of elastomeric material.

13. A heat exchanger capable of maintaining sterility during temperature variations comprising a metal inner conduit, an outer conduit having a length less than that of said inner conduit, an end cap at each end of said outer conduit for providing a fluid path between said inner and outer conduits, wherein each said end cap is of elastic material for at least partially accommodating expansion or contraction of said inner conduit and comprises a first hollow portion cemented to said outer conduit and a second hollow portion having a hoop strength adequate to tightly grip said inner conduit to provide a pressure tight seal at a location substantially fixed with respect to said inner conduit during expansion or contraction of said inner conduit.