Differential air flow system for promoting bottom-up freezing of blood plasma in compressed bags
Inventors
SILVESTRE DUARTE, Andreia Filipa • SENA REGO, Pedro Gil • DA SILVA COMPLETO, Carlos Duarte
Assignees
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Publication Number
US-12268206-B2
Publication Date
2025-04-08
Expiration Date
Abstract
This disclosure relates to a method and system for fast freezing of a biological product (such as blood plasma) contained in an individual bag or a plurality of bags. This disclosure relates to a method and a-system for freezing plasma in an individual bag or a plurality of bags, favoring bottom-up ice-growth, by implementing a differential air flow on top and bottom surfaces of a horizontally placed bag or bags filled with plasma. This disclosure relates to a method and a differential air flow system for freezing plasma, wherein the heat transfer coefficient on a bottom of a bag is at least 10 times larger than at a top. This disclosure relates to a differential air flow system and method for freezing plasma, wherein the differential air flow on top and bottom surfaces of a plasma bag is imposed by at least one fan or blower.
Core Innovation
The invention provides a differential air-flow plasma freezer that promotes bottom-up ice-growth in a horizontally placed, compressed biological fluid bag. Freezing is performed in a controlled temperature chamber, where cold air is driven so that the air flow at the bottom of the bag or case is higher than the air flow at the top of the bag or case.
The core concept imposes different heat transfer conditions on opposite sides of the bag by requiring a heat transfer coefficient on the top of the bag that is less than 5 W/(m2·°C) and a heat transfer coefficient on the bottom of the bag that is higher than 20 W/(m2·°C), allowing bottom-up ice-growth. In additional refinements, the top heat transfer coefficient is limited to less than 2 W/(m2·°C) while the bottom heat transfer coefficient is increased above 50 W/(m2·°C), and the differential air flow includes a cold-air velocity in a range from 1 m/s to 10 m/s.
A support is used to place the bag or a case containing the bag and to enable compression of the bag or case against the support, including a rigid material with low heat conductivity for compressing against the support. The air flow system is configured to drive cold air inside the controlled temperature chamber by blowing the cold air below the compressed bag or case such that velocity below the bag or case is higher than velocity above the bag or case.
Claims Coverage
The partial content contains two independent claims. Both focus on freezing biological fluid in a bag using bottom-up ice-growth by creating differential air flow and constraining top-versus-bottom heat transfer coefficients; the second independent claim additionally defines an air flow system configured for the chamber and the compression arrangement.
Differential air flow bottom-up freezing in a controlled temperature chamber
A method for freezing an individual bag or a plurality of bags containing biological fluid, favoring bottom-up ice-growth, comprising providing a controlled temperature chamber; placing an air flow system into the controlled temperature chamber; placing a bag or a case containing the bag on a support; compressing the bag or case against the support; driving air inside the controlled temperature chamber to obtain a differential air flow for freezing the bag by blowing air on the bottom of the bag or case such that a velocity of the air on the bottom is higher than a velocity of the air on the top, allowing bottom-up ice-growth; wherein a heat transfer coefficient on the top of the bag is less than 5 W/(m2·°C) and a heat transfer coefficient on the bottom of the bag is higher than 20 W/(m2·°C); and wherein the air flow has a velocity in a range from 1 m/s to 10 m/s.
Air flow system with compression and bottom-blown differential flow for bottom-up ice-growth
An air flow system for placing in a controlled temperature chamber having cold air at a temperature sufficient to freeze biological fluid in a bag, favoring bottom-up ice-growth, comprising a support for holding the bag or a case containing the bag; and a rigid material with low heat conductivity to compress the held bag or case against the support, wherein the air flow system is configured to drive the cold air inside the controlled temperature chamber to obtain a differential air flow for freezing the biological fluid in the bag, wherein the differential air flow is obtained by blowing the cold air below the compressed bag or case such that velocity of the cold air below the bag or case is higher than velocity of the cold air above the bag or case, allowing bottom-up ice-growth of the biological fluid in the bag.
Across the independent claims, the main inventive elements are the creation of bottom-versus-top differential air flow within a controlled temperature chamber while maintaining specified top and bottom heat transfer coefficients, combined with compressing the bag or case against a support using a rigid low-heat-conductivity material. The air flow below the compressed bag is higher in velocity than above to allow bottom-up ice-growth.
Stated Advantages
Allows bottom-up ice-growth of the biological fluid in the bag.
Documented Applications
Freezing biological fluid in an individual bag or a plurality of bags in a controlled temperature chamber, including horizontally placed, compressed biological fluid bags.
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