Breathing gas heat exchanger

• US 3,895,675 A
• Filed: 08/15/1973
• Issued: 07/22/1975
• Est. Priority Date: 08/15/1973
• Status: Expired due to Term

• Current Assignee: Charles B. Jones Jr, Charles R. Rein
• Original Assignee: Charles B. Jones Jr, Charles R. Rein
• Inventors: Rein, Charles R., Jones, Charles B. Jr.
• Primary Examiner(s): Myhre, Charles J.
• Assistant Examiner(s): Streule, Jr., Theophil W.
• Application Number:
  US05/388,704
• Time in Patent Office: 706 Days
• Field of Search: 165/164,46,179,165,66 2/2.1R 128/146,212
• US Class Current: 165/164
• CPC Class Codes: F28F 1/42 the means being both outside and inside the tubular element
• CPC Class Codes: F28F 1/424 Means comprising outside portions integral with inside portions
• CPC Class Codes: F28F 21/067 Details
• CPC Class Codes: Y10S 165/355 having separate flow passage for two distinct fluids

Abstract

A heat exchanger for use in intermittent flow situations in breathing apparatus is disclosed that includes a plurality of thermally conductive rod members extending through a septum member that divides a duct into a plurality of counter flow passages. The exchanger is uniquely adapted to efficient heat exchange in intermittent gas flow situations by the provision of a septum member that is relatively low in thermal energy storage capacity and relatively low in thermal conductivity in directions parallel to flow in the passages.

Claims

1. An intermittent flow heat exchanger for use in a breathing system wherein gas to be breathed is to be heated to higher temperatures by exchange of heat from gas that has been breathed, and wherein said gases are each moved intermittently so as to have flow periods and non-flowing periods, said exchanger comprising:

an elongated duct having walls formed of rigid, thermally insulating material, said duct having a substantially uniform cross section from end-to-end;

septum means, disposed in said duct, for dividing space within said duct into a plurality of passages extending lengthwise of said duct, said septum means comprising a thin panel formed of rigid, thermally insulating material free of relatively heat conductive material lying in a plane extending parallel to said directions of flow;

a plurality of elongated, thermally conductive metal wires extending through said septum means at right angles thereto, and transversely across said passages said metal wires being received in pre-formed holes extending through said panel, and effectively obturating said holes;

said panel together with the portions of said metal wires that are covered thereby being characterized as having low thermal capacity whereby thermal energy applied to said metal wires in a first passage during one of said flow periods for said gas that has been breathed is conducted, substantially without capacitive delay, to said gas to be breathed in a second of said passages.

2. A heat exchanger as defined in claim 1, and wherein:

said wires have their opposite ends embedded in said duct walls, whereby they are supported against distortion and insulated against heat loss therefrom to the exterior of said duct.

3. A heat exchanger for intermittent gas flow heat exchange in breathing apparatus, said heat exchanger comprising:

an elongated duct having a uniform cross-section along its length, said duct comprising walls formed of rigid, thermally insulating material;

first and second septum members, each formed of panels of rigid, thermally insulating materIal, said septum members being in spaced, parallel relation and dividing said duct into first, second, and third parallel passages;

a plurality of wire, heat conducting fins each having a uniform cross-sectional configuration from end to end and each extending through both of said septum members at right angles thereto, and across said first, second, and third passages, said fins each having its opposite ends embedded in said duct walls;

said septum members being further characterized by lack of heat conductive and heat capacitive capabilities in zones penetrated by, or in thermal communication with, said fins.

4. A heat exchanger as defined in claim 3, and wherein:

said wire, heat conducting fins are in spaced, parallel relation to one another and are arranged in columns and rows of equal spacing; and

said wire, heat conducting fins having a density of about 100 per square inch of said septum members.