Parenteral fluid warmer apparatus and disposable cassette utilizing thin, flexible heat-exchange membrane

Claim 1

A disposable cassette adapted for placement between a pair of heating elements so as to warm parenteral fluids flowing through the cassette for intravenous delivery to a patient, the cassette comprising: insulative passageway means for insulating, supporting and spacing first and second heat conductive membrane means one from the other, and defining a thin, planar serpentine flow path having top and bottom sides and an inlet end and an outlet end, such that a thin sheet of parenteral fluid enters the inlt end, travels through the serpentine flow path, and exits the outlet end; a first flexible, heat conductive membrane means supported on one side of said passageway means and providing heat transfer from one of the heating elements to one of the top and bottom sides of the serpentine flow path, said first heat conductive membrane means comprising an inlet port for communicating the parenteral fluid to the inlet end of the serpentine flow path, and an outlet port for exit of the warmed parenteral fluid from the serpentine flow path; a second flexible, heat conductive membrane means supported on an opposite side of said passageway means so as to be insulated from the first flexible, heat conductive membrane, and providing heat transfer from the other heating element to the other of the top and bottom sides of the serpentine flow path, such that said serpentine flow path is essentially completely covered on the top and bottom sides thereof from the inlet to the outlet ends by the first and second heat conductive membrane means which are insulated and spaced from one another; and support means providing a peripheral framework that encompasses and sealingly receives and holds generally in the plane of the serpentine flow path essentially all of the peripheral edges of the first and second heat conductive membrane means with the insulative passageway means sandwiched therebetween without obstructing contact of the first and second heat conductive membrane means with the pair of heating elements when the cassette is placed therebetween.

Claim 13

An apparatus for heating parenteral fluids for intravenous delivery to a patient, comprising: a disposable cassette means for transferring heat to parenteral fluids flowing therethrough, the cassette means comprising: insulating passageway means defining a thin, planar serpentine flow path having top and bottom sides and an inlet end and an outlet end, such that a thin sheet of parenteral fluid enters the inlet end, travels through the serpentine flow path, and exits the outlet end; a first flexible, heat conductive membrane means supported on one of the top or bottom sides of the insulating passageway means and providing heat transfer to one of the top and bottom sides of the serpentine flow path; a second flexible, heat conductive membrane means supported on the other of the top or bottom sides of the insulating passageway means so as to be both spaced and insulated from the first flexible, heat conductive membrane means, and providing heat transfer to the other of the top and bottom sides of the serpentine flow path; and support means providing a peripheral framework that sealingly receives and holds the first and second heat conductive membrane means with the passageway means; and heating means in contact with said first and second heat conductive membrane means for generating a gradation of heat energy such that more heat energy is available for transfer to the parenteral fluid at the inlet end of the serpentine flow path than is available for transfer to the parenteral fluid at the outlet end of the serpentine flow path.

Claim 14

An apparatus for heating parenteral fluids for intravenous delivery to a patient, comprising: a disposable cassette means for transferring heat to parenteral fluids flowing therethrough, the cassette means comprising: insulating passageway means defining a thin, planar serpentine flow path having top and bottom sides and an inlet end and an outlet end, such that a thin sheet of parenteral fluid enters the inlet end, travels through the serpentine flow path, and exits the outlet end; a first flexible, heat conductive membrane means supported on one of the top or bottom sides of the insulating passageway means and providing heat transfer to one of the top and bottom sides of the serpentine flow path; a second flexible, heat conductive membrane means supported on the other of the top or bottom sides of the insulating passageway means so as to be both spaced and insulated from the first flexible, heat conductive membrane means, and providing heat transfer to the other of the top and bottom sides of the serpentine flow path; and support means providing a peripheral framework that sealingly receives and holds the first and second heat conductive membrane means with the passageway means; and heating means in contact with said first and second heat conductive membrane means for generating a gradation of heat energy such that more heat energy is available for transfer to the parenteral fluid at the inlet end of the serpentine flow path than is available for transfer to the parenteral fluid at the outlet end of the serpentine flow path.

Claim 17

An apparatus as defined in claims 12 or 14 wherein the first and second heat conductive membrane means or each comprised of a thin, flexible metallic foil.

Claim 21

An apparatus as defined in claims 12 or 14 wherein the metallic foil is a thin, flexible heat conductive plastic material.

Claim 30

An apparatus for heating parenteral fluids for intravenous delivery to a patient, comprising: a disposable cassette means for transferring heat to parenteral fluids flowing therethrough, the cassette means comprising: a unitary, insulating member having opposing end and side pieces joined together to form a medial section that is mostly open, the opening of said medial section being divided to form a serpentine flow path by a plurality of insulating path separators alternately extending into the opening from the opposing end pieces; first and second heat conductive membrane means sealingly joined to the unitary member at the opposing end and side pieces and at the path separators on top and bottom surfaces thereof to form an enclosed fluid-tight serpentine flow path between the plurality of path separators but without permitting the first and second heat conductive membrane means to contact one another; and support means providing a peripheral framework that sealingly receives and holds the first and second heat conductive membrane means with the unitary member; first and second hating blocks, one heating block contacting the first heat conductive membrane means and the other heating block contacting the second heat conductive membrane means; and heating means for generating at each heating block a gradation of heat energy such that more heat energy is available for transfer to the parenteral fluid at the inlet end of the serpentine flow path than is available for transfer to the parenteral fluid at the outlet end of the serpentine flow path.

Claim 31

An apparatus for heating parenteral fluids for intravenous delivery to a patient, comprising: a disposable cassette means for transferring heat to parenteral fluids flowing therethrough, the cassette means comprising: a unitary, insulating member having opposing end and side pieces joined together to form a medial section that is mostly open, the opening of said medial section being divided to form a serpentine flow path by a plurality of insulating path separators alternately extending into the opening from the opposing end pieces; first and second heat conductive membrane means sealingly joined to the unitary member at the opposing end and side pieces and at the path separators on top and bottom surfaces thereof to form an enclosed fluid-tight serpentine flow path between the plurality of path separators but without permitting the first and second heat conductive membrane means to contact one another; and support means providing a peripheral framework that sealingly receives and holds the first and second heat conductive membrane means with the unitary member; first and second hating blocks, one heating block contacting the first heat conductive membrane means and the other heating block contacting the second heat conductive membrane means; and heating means for generating at each heating block a gradation of heat energy such that more heat energy is available for transfer to the parenteral fluid at the inlet end of the serpentine flow path than is available for transfer to the parenteral fluid at the outlet end of the serpentine flow path.