Electric blood warmer utilizing metallic ribbon flow cartridge and low thermal mass heating units

Claim 1

An apparatus for warming blood for transfusion, comprising: a fluid-impervious rigid flat metal cartridge defining an enclosed cavity of small volume, having an inlet port and an outlet port at opposite ends thereof, the interior of said cartridge being compatible with the temporary storage of blood, the exterior of said cartridge having two flat heatable surfaces; said cartridge including a pair of thin metal generally rectangular planar members spaced slightly apart and in parallelism with each other, said members being sealed together at their edges to define an unobstructed constant-width and uniform-thickness thin ribbon-like conduit for fluid between the interior surfaces of said members; said cartridge further including a trough-shaped elongated recess defining an inlet chamber communicating with said inlet port, and a trough-shaped elongated recess defining an outlet chamber communicating with said outlet port, each chamber running completely across and communicating with a corresponding end of said conduit, whereby fluid can uniformly flow into and out of said thin ribbon-like conduit across the full conduit width; heating means including a pair of heating units each having a low thermal mass, a uniform heat flux distribution, and a flat clamping surface disposed to clamp against a corresponding flat outer surface of said cartridge between the inlet and outlet chambers thereof, for heating each of said cartridge heatable surfaces; temperature sensing means embedded in one of said heating units closely adjacent to said clamping surface, positioned to lie closely adjacent to the outer surface of said cartridge immediately adjacent to the outlet chamber thereof; and control means responsive to said temperature sensing means to control the amount of heat supplied by said heating means to each cartridge flat side.

Claim 2

An apparatus for warming blood for transfusion, comprising: a fluid-impervious rigid flat metal cartridge defining an enclosed cavity of small volume, having an inlet port and an outlet port at opposite ends thereof, the interior of said cartridge being compatible with the temporary storage of blood, the exterior of said cartridge having two flat heatable surfaces; said cartridge including a pair of thin metal generally rectangular planar members spaced slightly apart and in parallelism with each other, said members being sealed together at their edges to define an unobstructed constant-width and uniform-thickness thin ribbon-like conduit for fluid between the interior surfaces of said members; said cartridge further including a trough-shaped elongated recess defining an inlet chamber communicating with said inlet port, and a trough-shaped elongated recess defining an outlet chamber communicating with said outlet port, each chamber running completely across and communicating with a corresponding end of said conduit, whereby fluid can uniformly flow into and out of said thin ribbon-like conduit across the full conduit width; heating means including a pair of heating units each having a low thermal mass, a uniform heat flux distribution, and a flat clamping surface disposed to clamp against a corresponding flat outer surface of said cartridge between the inlet and outlet chambers thereof, for heating each of said cartridge heatable surfaces; temperature sensing means embedded in one of said heating units closely adjacent to said clamping surface, positioned to lie closely adjacent to the outer surface of said cartridge immediately adjacent to the outlet chamber thereof; and control means responsive to said temperature sensing means to control the amount of heat supplied by said heating means to each cartridge flat side.

Claim 6

An apparatus for warming blood for transfusion, comprising: a fluid-impervious rigid flat metal cartridge defining an enclosed cavity of small volume, having an inlet port and an outlet port at opposite ends thereof, the interior of said cartridge being compatible with the temporary storage of blood, the exterior of said cartridge having two flat heatable surfaces; said cartridge including a pair of thin metal generally rectangular planar members spaced slightly apart and in parallelism with each other, at least one planar member having on the surface facing the other planar member and running in the direction from inlet port end to outlet port end at least one straight narrow raised ridge of uniform height equal to the distance said members are spaced apart, said planar members being sealed together at their edges to define at least two unobstructed constant-width and uniform-thickness thin ribbon-like conduits for fluid between the interior surfaces of said members; said cartridge further including a trough-shaped elongated recess defining an inlet chamber communicating with said inlet port, and a trough-shaped elongated recess defining an outlet chamber communicating with said outlet port, each chamber running completely across and communicating with a corresponding end of every conduit, whereby fluid can uniformly flow into and out of each thin ribbon-like conduit across each full conduit width; heating means including a pair of heating units each having a low thermal mass, a uniform heat flux distribution, and a flat clamping surface disposed to clamp against a corresponding flat outer surface of said cartridge between the inlet and outlet chambers thereof, for heating each of said cartridge heatable surfaces; temperature sensing means embedded in one of said heating units closely adjacent to said clamping surface, positioned to lie closely adjacent to the outer surface of said cartridge immediately adjacent to the outlet chamber thereof; and control means responsive to said temperature sensing means to control the amount of heat supplied by said heating means to each cartridge flat side.

Claim 7

An apparatus for warming blood for transfusion, comprising: a fluid-impervious rigid flat metal cartridge defining an enclosed cavity of small volume, having an inlet port and an outlet port at opposite ends thereof, the interior of said cartridge being compatible with the temporary storage of blood, the exterior of said cartridge having two flat heatable surfaces; said cartridge including a pair of thin metal generally rectangular planar members spaced slightly apart and in parallelism with each other, at least one planar member having on the surface facing the other planar member and running in the direction from inlet port end to outlet port end at least one straight narrow raised ridge of uniform height equal to the distance said members are spaced apart, said planar members being sealed together at their edges to define at least two unobstructed constant-width and uniform-thickness thin ribbon-like conduits for fluid between the interior surfaces of said members; said cartridge further including a trough-shaped elongated recess defining an inlet chamber communicating with said inlet port, and a trough-shaped elongated recess defining an outlet chamber communicating with said outlet port, each chamber running completely across and communicating with a corresponding end of every conduit, whereby fluid can uniformly flow into and out of each thin ribbon-like conduit across each full conduit width; heating means including a pair of heating units each having a low thermal mass, a uniform heat flux distribution, and a flat clamping surface disposed to clamp against a corresponding flat outer surface of said cartridge between the inlet and outlet chambers thereof, for heating each of said cartridge heatable surfaces; temperature sensing means embedded in one of said heating units closely adjacent to said clamping surface, positioned to lie closely adjacent to the outer surface of said cartridge immediately adjacent to the outlet chamber thereof; and control means responsive to said temperature sensing means to control the amount of heat supplied by said heating means to each cartridge flat side.