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JP-7854717-B2 - Differential airflow system to facilitate bottom-up freezing of plasma in a compressed bag

JP7854717B2JP 7854717 B2JP7854717 B2JP 7854717B2JP-7854717-B2

Inventors

  • アンドレイア フィリッパ シルヴェストル デュアルテ
  • ペドロ ギル セナ レゴ
  • カルロス デュアルテ ダ シルヴァ コンプリト

Assignees

  • スマートフリーズ エルディーエイ

Dates

Publication Date
20260507
Application Date
20210428
Priority Date
20200430

Claims (15)

  1. A method for freezing individual bags or multiple bags containing a biological agent to promote bottom-up ice crystal growth, comprising the following steps: The steps include preparing the control temperature chamber, The steps include: arranging a differential airflow system within the control temperature chamber; The steps include placing a bag or a case for storing the bag on a support, The steps of compressing the bag or case against the support, The steps include: sending cold air into the control temperature chamber to obtain a differential airflow for freezing the bag; Equipped with, The differential airflow is achieved by blowing air onto the bottom of the bag such that the air velocity at the bottom of the bag is higher than the air velocity at the top of the bag, thereby promoting bottom-up ice crystal growth. The method wherein the heat transfer coefficient at the top of the bag must be less than 5 W/( m² ·°C), and the heat transfer coefficient at the bottom of the bag must be greater than 50 W/( m² ·°C), and the air blown onto the bottom of the bag has a velocity in the range of approximately 1 m/s to approximately 10 m/s.
  2. A method for freezing a bag according to claim 1, wherein the heat transfer coefficient at the top of the bag is less than 2 W/( m² ·°C), the heat transfer coefficient at the bottom of the bag is higher than 20 W/( m² ·°C), and the air blown onto the bottom of the bag has a velocity in the range of about 1 m/s to about 10 m/s.
  3. A method for freezing a bag according to any one of claims 1 to 2, wherein the differential airflow is achieved by a fan and a flow conveyor that supply and blow cold air onto the bottom of the bag, the support, or the fins of the support.
  4. A method for freezing a bag according to any one of claims 1 to 3, wherein the support is a horizontal configuration or a vertically stacked configuration consisting of at least two layers.
  5. An airflow system for freezing individual bags or a group of bags containing a biological agent to promote bottom-up ice crystal growth, using the method according to any one of claims 1 to 4, The system includes a control temperature chamber for arranging the aforementioned airflow system, An airflow system configured to be placed inside a controlled temperature chamber, A bag or case, or a support for holding multiple bags or cases, The aforementioned bag or case, or a compression means for compressing the plurality of bags or cases, Equipped with, The airflow system is configured to supply cold air into the control temperature chamber in order to obtain a differential airflow for freezing the bag. The differential airflow is achieved by blowing air onto the bottom of the bag such that the air velocity at the bottom of the bag is higher than the air velocity at the top of the bag, thereby promoting bottom-up ice crystal growth. An airflow system in which the heat transfer coefficient at the top of the bag must be less than 5 W/( m² ·°C), and the heat transfer coefficient at the bottom of the bag must be greater than 20 W/( m² ·°C).
  6. An airflow system according to claim 5, wherein differential airflow on the upper and lower surfaces of the bag is provided by at least one fan.
  7. An airflow system according to any one of claims 6, further comprising a controller for controlling the speed of the fan.
  8. An airflow system according to claim 6 or 7, further comprising a flow conveyor that drives the air from the fan to the bottom surface of the bag, wherein the air in the flow conveyor has a velocity in the range of 1 m/s to 10 m/s.
  9. An airflow system according to any one of claims 5 to 8, wherein the support has a horizontal configuration.
  10. An airflow system according to any one of claims 5 to 9, wherein the bag or the case housing the bag is arranged on the support in a horizontal configuration.
  11. An airflow system according to any one of claims 5 to 9, wherein the bag or case housing the bag is arranged on the support in a vertical stacking configuration, and the airflow system further comprises airflow channels that allow air to flow within each layer such that the bottom of the bag or the bottom of the case is exposed to an airflow of a higher velocity.
  12. An airflow system according to any one of claims 5 to 11, wherein the support has fins.
  13. An airflow system according to any one of claims 5 to 12, further comprising a case for housing a bag.
  14. An airflow system according to any one of claims 5 to 13, wherein the case is made of a polymer, cardboard, or an airflow system having low thermal conductivity.
  15. An airflow system according to any one of claims 5 to 14, wherein the compression means is made of a rigid material having low thermal conductivity, such as plastic or polymer.

Description

This disclosure relates to a method and system for rapidly freezing one or more bags containing biological products, particularly plasma. In particular, this disclosure relates to a differential airflow system for facilitating bottom-up freezing of plasma within a compressed bag. Biological fluids, such as plasma, are typically collected from donors, processed, and stored, usually frozen to minimize degradation until use. Generally, bags are containers selected for biological fluids and are made from biocompatible materials. Bags can have several forms, capacity options, safety features, and other properties to improve the overall process. Regarding plasma preservation, freezing is a crucial step, as fresh, frozen plasma is the primary source of coagulation factors (particularly factor VIII) used in patients with hemorrhagic disorders. Existing medical and scientific literature recommends that plasma should be frozen at -25°C or below to achieve the highest yield of factor VIII, and that a decrease in factor VIII content occurs during freezing when plasma coagulation takes longer than one hour. Therefore, in recent years, several freezers, especially those applied to plasma freezing, have been developed for the purpose of rapidly freezing plasma stored in bags. These and other purposes, features, and advantages of this disclosure will become clear when the following detailed description is read in conjunction with the accompanying drawings. This shows the recovery of factor VIII after freezing two plasma bags at -45°C inside a controlled temperature chamber using a differential airflow system that promotes bottom-up ice crystal growth according to this disclosure. A schematic diagram of a differential airflow system 200 for a freezing bag 100 is shown, which ensures that the heat transfer efficiency at the bottom 101 of the bag is greater than that at the top 102, making it suitable for bottom-up ice crystal growth. This is a schematic perspective view of a differential airflow system for a bag 100, which uses a fan 300 to achieve differential airflow 200 on the upper 102 and bottom 101 surfaces of the bag 100 placed on a support 500. This is a cross-sectional perspective view of a differential airflow system having a flow conveyor 400 with an inlet 401, a channel 402, and an outlet 403, which sends outside air from a fan 300 through fins 501 connected to a support 500, maximizing heat transfer from the outside air to the support 500 and, consequently, to the bottom 101 of the bag 100. This is a cross-sectional perspective view of the differential airflow system according to the present disclosure, showing a support 500 connected to the fins 501 for transferring heat to the bottom of the bag 100. This is a perspective view of a differential airflow system comprising multiple fans 30 for freezing multiple bags 100, as disclosed herein. This is a perspective view from the bottom side of a case 600 that houses a bag 100, the case having an opening 601 at the bottom to promote heat transfer on the bottom surface of the bag. This is a perspective view of a case 600 for housing a bag 100, with an additional layer 602 of a low thermal conductivity material on the top of the case, as seen from the top surface. This is a perspective view of a differential airflow system that freezes multiple bags 100 inside a case 600, having a compression means 700 for compressing the bags. This is a system breakdown perspective view. This is a cross-sectional view of the system. This is a cross-sectional view of the system. This is a perspective view of the system from the bottom. This is a perspective view of the system from the top side. This is a system with a different configuration, and 402 is a cross-sectional view showing the channel of the airflow 200. This is a perspective view of systems with different configurations. This section describes the purpose of the disclosure and the fundamental assumptions of the proposed embodiments. As mentioned above, one major limitation in the storage of biological fluids such as plasma is the freezing step. When using existing methods and equipment during freezing, ice grows from the walls of the container towards the middle, and the solute is gradually concentrated in the middle of the plasma bag, exposing factor VIII molecules to high concentrations of salt, resulting in molecular inactivation and, consequently, loss of factor VIII. Therefore, we have found that by applying differential airflow (with different airflow rates) to the top and bottom surfaces of a plasma bag (placed horizontally), and by favoring heat transfer from the bottom, a bottom-up freezing geometry can be achieved, leading to high recovery of factor VIII (see Figure 1). In this disclosure, differential airflow means that the heat transfer coefficient at the bottom of the bag differs from that at the top of the bag, and preferably, the heat transfer coefficient at the bottom of the bag is preferentially 10 times gr