Electric blood warmer utilizing heating by condensation
First Claim
1. An apparatus for warming blood for transfusion comprising:
- (A) at least one heating unit including;
(1) a rigid metal housing having walls, vertically disposed, enclosing a hermetically sealed air-free space having a lower liquid phase evaporation region containing an evaporatable liquid and an upper vapor phase condensation region, one flat wall adjacent said condensation region functioning as a heating plate by transferring heat from vapor therein,(2) external etched foil electric heating means adjacent said evaporation region for generating vapor from said liquid, and(3) temperature sensing means adjacent said condensation region for sensing the temperature of vapor therein,(B) means for connecting said etched foil electric heating means to a source of electric power,(C) control means responsive to said temperature sensing means to control the amount of heat supplied by said eldered foil electric heating means to said heating unit liquid phase evaporation region, and(D) means for passing blood in conductive heat transference contact with said heating plate.
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Accused Products
Abstract
An apparatus for warming refrigerated blood to physiologic temperature during transfusion at flow rates from zero to greater than 160 milliliters per minute. The apparatus consists primarily of two hollow metal rectangular box shaped heating units containing a water reservoir in equilibrium with a larger volume of water vapor. Heat is applied to the water reservoir, generating steam which condenses on one wall of each heating unit serving as a heating plate. Heat is then transferred by conduction to a thin metal cartridge or plastic pouch type conduit sandwiched between the two heating plates. Very high heat transfer coefficients maintain heating plates at constant temperature without the possibility of damage to blood by local overheating.
65 Citations
19 Claims
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1. An apparatus for warming blood for transfusion comprising:
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(A) at least one heating unit including; (1) a rigid metal housing having walls, vertically disposed, enclosing a hermetically sealed air-free space having a lower liquid phase evaporation region containing an evaporatable liquid and an upper vapor phase condensation region, one flat wall adjacent said condensation region functioning as a heating plate by transferring heat from vapor therein, (2) external etched foil electric heating means adjacent said evaporation region for generating vapor from said liquid, and (3) temperature sensing means adjacent said condensation region for sensing the temperature of vapor therein, (B) means for connecting said etched foil electric heating means to a source of electric power, (C) control means responsive to said temperature sensing means to control the amount of heat supplied by said eldered foil electric heating means to said heating unit liquid phase evaporation region, and (D) means for passing blood in conductive heat transference contact with said heating plate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An apparatus for warming blood for transfusion comprising:
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(A) a first fixed heating unit including; (1) a rigid metal housing having walls vertically disposed enclosing a hermetically sealed air-free space having a lower liquid phase evaporation region containing a reservoir of evaporatable liquid, and an upper vapor phase condensation region, one flat wall adjacent said condensation region functioning as a heating plate by transfering heat from vapor therein, (2) external electric heating means adjacent said evaporation region for generating vapor from said liquid, and (3) temperature sensing means adjacent said condensation region for sensing the temperature of vapor therein, (B) a similar second movable heating unit hingedly supported by said first unit, the flat heating plate of each said heating units being in parallel facing and closely spaced apart relation, and (C) latch means on said heating unit for releasably clamping a flat blood warming cartridge or pouch therebetween, (D) means for connecting said heating means to a source of electric power, and (E) control means responsive to said temperature sensing means to control the amount of heat supplied by said heating means to said heating unit liquid phase evaporation regions. - View Dependent Claims (17, 18, 19)
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Specification