Volute type square box laminated structure membrane lung oxygenator and pre-filling method thereof

Abstract

The invention belongs to the technical field of extracorporeal membrane lung oxygenation, and provides a volute type square box laminated structure membrane lung oxygenator and a pre-filling method thereof.A volute type runner is arranged in a square box laminated structure of the square box laminated structure membrane lung oxygenator and comprises a spiral section and a plurality of flow dividing sections, the input ends of the flow dividing sections are connected with the spiral section, and the output ends of the flow dividing sections are connected with the spiral section; the output end is located at the internal corner position of the square box laminated structure, high-flow-speed pre-filled liquid enters the spiral section at the inlet, then flows to the flow dividing section under the high-speed inertia effect and preferentially flows to the internal corner position of the square box laminated structure, and the effect of discharging bubbles at the four corners of the square box laminated structure is guaranteed. Moreover, by means of the cooperation of the volute type flow channel and the high-speed pre-filled liquid, the flushing capacity of all positions in the membrane lung oxygenator is improved, the membrane lung oxygenator does not need to be shaken, oscillated and the like, the workload of medical staff is reduced, and the problem that consumable items are damaged due to improper shaking and flapping actions is solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of extracorporeal membrane oxygenation consumable kits, and particularly relates to a volute type square box laminated structure membrane oxygenator and a pre-charging method thereof. BACKGROUND

[0002] An extracorporeal membrane oxygenation (ECMO) consumable kit is composed of a blood pump, a membrane oxygenator and a pipeline connecting them. Because bubbles rushing into the human body can cause gas embolism, which seriously endangers the life safety of patients, before the ECMO operation is carried out, physiological saline or crystal liquid and the like are used as pre-charging liquid to pre-charge the consumables, fill the entire pipeline and fully empty the air in the pipeline.

[0003] At present, the ECMO consumable pre-charging needs a long time, generally 10 minutes to 20 minutes; mainly because the membrane oxygenator parts are a kind of porous structure, which is not easy to fully discharge the air bubbles mixed in the pores, and the operation is difficult. Especially for the membrane oxygenator with a square box laminated structure, the pre-charging liquid has weak flushing ability at the four corners, and air bubbles are most likely to be left. Generally, a large flow flushing and constant shaking of the membrane oxygenator are needed to achieve the purpose of completely discharging the air bubbles, which increases the workload of medical staff. Moreover, if the shaking and patting actions are improper, the consumables will be damaged. In addition, in some schemes, the flushing ability can be enhanced by setting four branches in the main pipe, but the main pipe is relatively fragile, and the shape is not beautiful, not compact, and difficult to manufacture. SUMMARY

[0004] In order to solve the above problems, the application provides a volute type square box laminated structure membrane oxygenator and a pre-charging method thereof. In the square box laminated structure of the membrane oxygenator, a volute type flow channel is arranged, specifically, the volute type flow channel includes a spiral segment and a plurality of shunt segments, the input end of the shunt segment is connected with the spiral segment, and the output end is located at the internal corner position of the square box laminated structure. After the pre-charging liquid with high flow rate enters the spiral segment at the inlet, it flows to the shunt segment under the action of high-speed inertia, preferentially flows to the internal corner position of the square box laminated structure, and ensures the discharge effect of air bubbles at the four corners of the square box laminated structure. Moreover, the ECMO pump has a large margin in hardware indicators, has a special high-speed pre-charging working mode, and the rotating speed is as high as 9000 revolutions per minute (the highest rotating speed in the normal extracorporeal circulation working mode is only 4500 revolutions per minute). In order to avoid misoperation, the high-speed pre-charging working mode is provided by a standby pump head, the pre-charging operation is completed on the standby pump head, and after the pre-charging is completed, the blood pump is transferred to the main working pump head for standby. The workload of medical staff is reduced, and the problem of damage to the consumables caused by improper shaking and patting actions is avoided.

[0005] In order to achieve the above object, the first aspect, the application provides a volute square box laminated structure membrane lung oxygenator which adopts the following technical scheme. A volute square box laminated structure membrane lung oxygenator, comprising a square box laminated structure, an inlet and an outlet arranged on the square box laminated structure, and a volute flow channel connected with the inlet; The volute flow channel comprises a spiral segment and a plurality of shunt segments; the input end of the spiral segment is connected with the inlet; the input end of the shunt segment is connected with the spiral segment, and the output end is located at the internal corner position of the square box laminated structure.

[0006] Further, the inlet is connected with a standby pump and a working pump, the standby pump can provide a liquid driving flow rate greater than that of the working pump; the cross-sectional area of the spiral segment gradually decreases instead of that of the shunt segment; and the cross-sectional area of the shunt segment is basically uniform.

[0007] Further, the membrane lung oxygenator is provided with a flow limiting part at the connection position of the two shunt segments and the spiral segment close to the inlet, the flow limiting part is a protrusion arranged outside the shunt segment; and the protrusion is arranged at a position opposite to the flow direction.

[0008] Further, the shunt segment is arranged in a flat slit structure, and the inner cross section of the slit structure gradually decreases in the direction from the spiral segment to the internal corner position of the square box laminated structure.

[0009] Further, at the connection position of the spiral segment and the shunt segment, the input end of at least one shunt segment adopts an inclined elliptical hole, and the inclination angle of the input end of the shunt segment is equal to the spiral angle at the connection position of the spiral segment.

[0010] Further, in the square box laminated structure, one volute flow channel is arranged on the side connected with the outlet, and the spiral segment is connected with the outlet through a pipeline; four slits are arranged in the volute flow channel at positions corresponding to the shunt segments.

[0011] Further, the shunt segment is arranged in a flat slit structure, and the inner cross section of the slit structure gradually decreases in the direction from the square box laminated structure to the spiral segment; at the connection position of the spiral segment and the shunt segment, the input end of at least one shunt segment adopts an inclined elliptical hole, and the inclination angle of the input end of the shunt segment is equal to the spiral angle at the connection position of the spiral segment.

[0012] Further, in the square box laminated structure, a comb-shaped flow channel is arranged on the side connected with the outlet pipeline, the comb-shaped flow channel comprises a plurality of sub-flow channels with different lengths, the plurality of sub-flow channels are symmetrically distributed on the side of the square box laminated structure connected with the outlet pipeline, and the plurality of sub-flow channels are all connected with the outlet through a concentrated flow channel.

[0013] In order to achieve the above-mentioned purpose, the second aspect, the application further provides a spiral casing square box laminated structure membrane lung oxygenator pre-charging method, adopts the following technical scheme: A spiral casing square box laminated structure membrane lung oxygenator pre-charging method adopts the spiral casing square box laminated structure membrane lung oxygenator as described in the first aspect, and the pre-charging liquid flows to the internal corner position of the square box laminated structure after entering the spiral segment at the inlet under the action of inertia.

[0014] Further, the pre-charging liquid is pumped into the inlet by the standby pump, and after passing through the spiral segment and the shunt segment, the pre-charging liquid flows to the internal corner position of the square box laminated structure for flushing; after pre-charging is completed, the blood is pumped into the inlet by the working pump, and the pumped blood uniformly flows through the membrane filament area.

[0015] Compared with the prior art, the application has the following beneficial effects: 1、In the square box laminated structure membrane lung oxygenator, a spiral casing flow channel is arranged in the square box laminated structure, specifically, the spiral casing flow channel comprises a spiral segment and a plurality of shunt segments, the input end of the shunt segment is connected with the spiral segment, and the output end is located at the internal corner position of the square box laminated structure; the pre-charging liquid with high flow rate flows to the shunt segment under the action of high-speed inertia after entering the spiral segment at the inlet, and preferentially flows to the internal corner position of the square box laminated structure, thereby ensuring the bubble discharge effect at the four corners of the square box laminated structure; and in combination with the spiral casing flow channel and the high-speed pre-charging liquid, the flushing capability of each position in the membrane lung oxygenator is improved, so that shaking and oscillation operations of the membrane lung oxygenator are not required, the workload of medical staff is reduced, and the problem of damage to consumables caused by improper shaking and beating actions is avoided.

[0016] 2、In the application, the inlet is connected with a standby pump and a working pump; the standby pump can provide a large liquid driving flow rate, and in combination with the spiral casing flow channel, the pre-charging liquid flow rate and flushing effect are ensured; and the working pump is used for pumping blood, and can ensure that the blood flows in the membrane lung oxygenator at a preset normal working flow rate.

[0017] 3、In the application, under the action of the standby pump, the pre-charging liquid is pushed to a high flow rate, so that the pre-charging liquid entering the square box laminated structure has high inertia; when the pre-charging liquid enters the membrane lung oxygenator along the spiral casing flow channel, the centrifugal force causes the pre-charging liquid to diverge to the periphery along the shunt segment, the shunt segment guides the high-speed impact pre-charging liquid to the four-corner position where small bubbles are prone to be left in the oxygenator, and the high-speed fluid flushing causes the small bubbles in the four-corner interior to move to the center area with a lower flow rate, thereby achieving the purpose of quickly removing the small bubbles trapped in the four-corner membrane filament gap.

[0018] 4. In this invention, the cross-sectional dimension of the flow divider perpendicular to the liquid flow direction gradually decreases along the spiral section to the internal corner position of the box stacked structure, thereby achieving the effect of greater flow velocity closer to the four corners of the box stacked structure, improving the flushing ability and bubble removal effect at the four corners of the box stacked structure.

[0019] 5. In this invention, by performing fluid simulation verification on the volute-type flow channel structure and optimizing the volute-type flow channel structure based on the verification results, the volute-type flow channel structure can perform air bubble removal under inertial action when the pre-filled liquid flows at high speed. The volute-type flow channel structure has a significant impact on the liquid flow direction. At the same time, under normal blood flow conditions, the volute-type flow channel structure has a smaller impact on the liquid flow direction and will not produce abnormal blood flow phenomena. At this time, the membrane fiber region is the main fluid resistance factor, ensuring that the blood flows evenly through the membrane fiber region.

[0020] 6. The present invention has a compact structure and is not difficult to manufacture. While ensuring performance, it improves aesthetics and process feasibility. Attached Figure Description

[0021] The accompanying drawings, which form part of this embodiment, are used to provide a further understanding of this embodiment. The illustrative embodiments and their descriptions are used to explain this embodiment and do not constitute an improper limitation of this embodiment.

[0022] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention; Figure 2 This is a streamline diagram of high-speed flow impact in Embodiment 1 of the present invention; Figure 3 This is a 3D streamline diagram of Embodiment 1 of the present invention; Figure 4 This is a pressure distribution diagram near the inlet end of the oxygenation section in Embodiment 2 of the present invention; Figure 5 This is a flow velocity distribution diagram near the inlet section of the oxygenation section in Embodiment 2 of the present invention; Figure 6 A streamline diagram of the oxygenator in Embodiment 2 of the present invention when it is injected with blood and enters normal working state; Figure 7 This is a flow velocity distribution diagram near the inlet section of the oxygenation section in Embodiment 2 of the present invention; Figure 8 This is a schematic diagram illustrating the relationship between viscous resistance and inertial resistance in Embodiment 2 of the present invention; Figure 9 This is a design flowchart for Embodiment 2 of the present invention; Figure 10 This is an example of flow field optimization in Embodiment 2 of the present invention; Figure 11This is a schematic diagram of the structure of Embodiment 5 of the present invention; Figure 12 This is a simulated flow rate diagram of Embodiment 5 of the present invention without increasing the flow-limiting section to a flow velocity of 4 m / s; Figure 13 This is a simulated streamline diagram of Embodiment 5 of the present invention without increasing the flow rate of the flow restrictor to 4 m / s. Figure 14 This is a simulated flow rate diagram of Embodiment 5 of the present invention without increasing the flow-limiting section to a flow velocity of 9 m / s; Figure 15 This is a simulated streamline diagram of Embodiment 5 of the present invention without increasing the flow rate of the flow restrictor to 9 m / s. Figure 16 This is a simulated flow rate diagram of a flow velocity of 4 m / s after adding a flow restrictor in Embodiment 5 of the present invention; Figure 17 This is a simulated streamline diagram of the flow velocity of 4 m / s after adding a flow restrictor in Embodiment 5 of the present invention; Figure 18 This is a simulated flow rate diagram of a flow velocity of 9 m / s after adding a flow restrictor in Embodiment 5 of the present invention; Figure 19 This is a simulated streamline diagram of a flow velocity of 9 m / s after adding a flow restrictor in Embodiment 5 of the present invention; Figure 20 This is a simulation diagram of a flow rate of 9 m / s after adding a flow restrictor in Embodiment 5 of the present invention; Figure 21 This is the flow velocity distribution of the spiral section cross-section without adding a flow restrictor in Embodiment 5 of the present invention; Figure 22 The velocity distribution of the spiral section cross-section when a flow-limiting part is added in Embodiment 5 of the present invention; Figure 23 This is a schematic diagram of the outlet connection channel in Embodiment 5 of the present invention; Figure 24 This is a simulated streamline diagram of the outlet surface under a flow velocity of 1.64 m / s in Embodiment 5 of the present invention; Figure 25 This is a simulated bottom streamline diagram of Embodiment 5 of the present invention after adding a comb-shaped flow channel; Figure 26 This is a simulated overall streamline diagram of Embodiment 5 of the present invention after adding comb-shaped flow channels; Among them, 1. Square box stacked structure; 2. Inlet; 3. Outlet; 4. Volute flow channel; 401. Spiral section; 402. Flow branching section; 403. Flow limiting section; 5. Comb-shaped flow channel; 6. Concentrated flow channel. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0025] Example 1: like Figure 1 As shown, this embodiment provides a volute-type box-type laminated membrane oxygenator, including a box-type laminated structure 1, an inlet 2 and an outlet 3 disposed on the box-type laminated structure 1, and a volute-type flow channel 4 disposed within the box-type laminated structure 1; the volute-type flow channel 4 includes a spiral section 401 and a flow-diverting section 402.

[0026] The box-shaped laminated structure 1 serves as the outer shell of the membrane oxygenator. In some embodiments, the box-shaped laminated structure 1 can be made of a transparent material, allowing medical personnel to clearly observe whether the oxygenation process is operating normally. For example, it can be made of medical-grade polycarbonate material such as Makron 2458, which offers high clarity. The box-shaped laminated structure 1 contains a membrane fiber region, which is the core component of the membrane oxygenator, the membrane lung. The membrane lung material can be PMP (poly-4-methyl-1-pentene) hollow fiber membrane, which has characteristics such as high permeability, high-efficiency oxygenation, low dissolution, and biocompatibility. Of course, in other embodiments, the box-shaped laminated structure 1 can also be replaced with a circular structure, or other regular or irregular structures. The box-shaped laminated structure 1 can also be made of a non-transparent material, or other transparent materials besides medical-grade polycarbonate material 2458. The membrane lung within the box-shaped laminated structure 1 can also be made of fiber membranes other than PMP hollow fiber membranes.

[0027] The inlet 2 is configured as a blood inlet for pumping blood in; the outlet 3 is configured as a blood outlet for allowing blood to flow out; the inlet 2 and the outlet 3 are connected by a pipe for transporting blood. It is understood that, in addition to the inlet 2 and outlet 3 for pumping blood in and out, the box-shaped stacked structure 1 also includes other structures such as an oxygen inlet and an exhaust outlet, as well as pipe connections and pipes, which can be implemented using conventional technology and will not be detailed here.

[0028] It should be noted that currently, when using pre-filling to remove air bubbles from membrane oxygenators, the bubbles cannot be completely removed, especially for membrane oxygenators with a box-like stacked structure. The pre-filling fluid has a weak flushing effect on the four corners, making it most likely for air bubbles to remain. Not only is it necessary to flush the tubing with a high flow rate for 5 to 10 minutes, but it is also necessary to shake the membrane oxygenator to generate vibration and assist in the removal of air bubbles. Even after pre-filling, tiny air bubbles will still remain in the pores of the membrane oxygenator, and the overall pre-filling time is 10 to 20 minutes. Furthermore, improper shaking and shaking can damage consumables.

[0029] To address the current problem of insufficient air bubble removal in membrane oxygenators, this embodiment incorporates a volute-type flow channel 4 within the box-shaped stacked structure 1. Specifically, the volute-type flow channel 4 includes a spiral section 401 connected to the inlet 2 and multiple branch sections 402. The input end of each branch section 402 is connected to the spiral section 401, and the output end of each branch section 402 extends to different internal corner positions within the box-shaped stacked structure 1. Furthermore, the input end can be understood as the location where liquid begins to enter the branch section 402; the output end is the corresponding location where liquid flows out of the branch section 402; and the internal corner can be understood as the angle between adjacent sidewalls within the box-shaped stacked structure 1, i.e., the location where air bubbles are difficult to remove.

[0030] The spiral section 401 is spiral in shape, with different branch sections 402 arranged at different positions within it. During pre-filling, the pre-filling liquid is pumped in through the inlet 2 by a standby pump. As the high-speed pre-filling liquid flows through the spiral section 401, it flows into each branch section 402 due to inertia, reaching various corners within the box-shaped stacked structure 1. This effectively flushes these corners, ensuring the removal of air bubbles. Simultaneously, the ultra-high flow rate of the pre-filling liquid enables rapid removal of gas from the entire box-shaped stacked structure 1, shortening the pre-filling time and improving pre-filling efficiency.

[0031] In some embodiments, the box-shaped stacked structure 1 has four corners, and four diversion sections 402 are evenly distributed around the spiral section 401. Of course, in other embodiments, the number of diversion sections 402 can be flexibly adjusted according to the number of internal corners of the box-shaped stacked structure 1, or according to the number of locations where air bubbles are difficult to remove in other structure membrane oxygenators.

[0032] Optionally, the cross-sectional dimension of the diversion section 402 perpendicular to the liquid flow direction gradually decreases along the direction from the spiral section 401 to the internal corner position of the square box stacked structure 1. That is, the closer to the corner position, the smaller the cross-sectional area that the fluid can flow through, thus achieving the purpose of increasing the flow velocity closer to the four corners of the square box stacked structure 1, thereby improving the flushing ability and bubble removal effect at the four corners of the square box stacked structure 1.

[0033] In some embodiments, the diversion section 402 can be configured as a flat slit structure. The inner cross-section of the slit structure gradually decreases along the direction from the spiral section 401 to the inner corner of the box-shaped stacked structure 1. That is, the closer to the corner, the smaller the cross-sectional area that allows fluid to flow through, thus achieving the purpose of increasing the flow velocity closer to the four corners of the box-shaped stacked structure 1. The flat slit structure of the diversion section 402, in addition to occupying less space and reducing the overall volume of the membrane oxygenator, also has a larger perimeter in contact with the fluid, which can improve heat transfer efficiency. At the connection between the spiral section 401 and the diversion section 402, at least one inlet of the diversion section 402 adopts the form of an inclined elliptical hole. The inclination angle of the diversion section 402 inlet is equal to or close to the spiral angle at the connection of the spiral section 401, which facilitates the easy flow of liquid from the spiral section 401 to the diversion section 402.

[0034] In summary, by incorporating a membrane oxygenator with a unique volute-type flow channel 4 structure, and combining this with a backup pump providing high-flow-rate pre-filling fluid, the pre-filling speed of consumables can be accelerated and the operational difficulty reduced, while ensuring the structural and performance safety of the membrane oxygenator components. Based on this, in this embodiment, the inlet 2 is connected to a backup pump and a working pump. The backup pump can provide a liquid-driven flow rate greater than that of the working pump. Specifically, the backup pump can provide a larger liquid-driven flow rate, which, combined with the volute-type flow channel 4, ensures the pre-filling fluid flow rate and flushing effect. The working pump is used for pumping blood in, ensuring that blood flows within the membrane oxygenator at a preset normal operating flow rate.

[0035] The backup pump has high reserve power, and its specific operating parameters can be adjusted and determined according to actual requirements. In one embodiment, the backup pump can reach a high speed of 9000 revolutions per minute, driving the pre-filled fluid to an ultra-high flow rate of 15 liters per minute. At this speed, the flow rate will not damage the oxygenation membrane fibers in the membrane oxygenator components. Optionally, a blood pump, a backup pump head, and a working pump head are provided. During the pre-filling operation, the blood pump is placed on the backup pump head to perform the pre-filling operation. After the pre-filling is completed, it is moved to the working pump head. The maximum flow rate of the working pump head is 7 liters per minute. Combined with various automation devices, all parameters are ensured to be within safe ranges.

[0036] In some embodiments, optionally, the standby pump and the working pump are connected to a pre-filling fluid storage device and a blood storage device, respectively; the standby pump and the working pump are connected in parallel through pipelines and then connected to the inlet; when pre-filling is required, the standby pump operates and the working pump does not operate, and the pre-filling fluid is pumped into the box-shaped stacked structure 1 for pre-filling; when pre-filling is complete, the working pump operates and the standby pump does not operate, and blood is pumped into the box-shaped stacked structure 1 for normal operation; the switching between pre-filling and blood pumping does not require manual intervention, thus improving efficiency.

[0037] In some embodiments, in the square box stacked structure 1, a volute flow channel is also provided on one side of the pipe connected to the outlet 3, and the spiral section 401 is connected to the outlet 3 through the pipe; four wide slits are also provided in the volute flow channel corresponding to the flow branch section 402 to reduce the blood outflow resistance in the four corner areas and make the flow field inside the membrane fiber area more stable.

[0038] Specifically, the diversion section 402 in the volute-type flow channel connecting outlet 3 can also be configured as a flat slit structure. The inner cross-section of the slit structure gradually decreases along the direction from the square box stacked structure 1 to the spiral section 401. That is, the closer to the spiral section 401, the smaller the cross-sectional area that the fluid can pass through, thus achieving the purpose of increasing the flow velocity closer to the spiral section 401. The flat slit structure of the diversion section 402, in addition to occupying less space and reducing the overall volume of the membrane oxygenator, also has a larger perimeter in contact with the fluid, which can improve heat transfer efficiency. Similarly, at the connection between the spiral section 401 and the diversion section 402, at least one inlet of the diversion section 402 adopts an inclined elliptical hole. The inclination angle of the diversion section 402 inlet is equal to or close to the spiral angle at the connection of the spiral section 401, which is conducive to the easy flow of liquid from the diversion section 402 to the spiral section 401.

[0039] One of the working principles or processes in this embodiment is as follows: Under the action of the standby pump, the pre-filled liquid is pushed to a high flow rate, so that the pre-filled liquid entering the square box stacked structure 1 has high inertia. When it enters the membrane oxygenator along the volute flow channel 4, the centrifugal force will cause the pre-filled liquid to disperse in all directions along the diversion section 402. After the pre-filled liquid enters the diversion section 402, the cross-sectional area through which it flows gradually decreases, making the flow rate of the pre-filled liquid even higher. The diversion section 402 guides the high-speed impacting pre-filled liquid to the four corners of the oxygenator where small air bubbles are easily trapped. The high-speed fluid flushing moves the small air bubbles inside the four corners to the central area where the flow rate is lower, thereby achieving the purpose of quickly removing the small air bubbles trapped in the gaps of the membrane filaments at the four corners.

[0040] Example 2: This embodiment provides a volute-type box-shaped laminated membrane oxygenator. Based on Embodiment 1, through fluid simulation verification of the volute-type flow channel structure and optimization of the volute-type flow channel structure based on the verification results, the volute-type flow channel structure can perform air bubble removal under inertial action during high-speed pre-filled fluid flow. The volute-type flow channel structure has a significant impact on the liquid flow direction. At the same time, under normal blood flow conditions, the volute-type flow channel structure has a smaller impact on the liquid flow direction and will not produce abnormal blood flow phenomena. At this time, the membrane fiber region is the main fluid resistance factor, ensuring that blood flows evenly through the membrane fiber region.

[0041] Optionally, the membrane oxygenator designed in this embodiment, including the volute-type flow channel 4, is subjected to simulation verification: Computational fluid dynamics (CFD) calculations were performed on the initially designed spiral section 401 and split section 402. Optionally, the Viscous Model viscosity model was used, with blood as the liquid material. The outlet and inlet parameters were set according to the operating conditions, with a normal operating flow rate of 0.5 L / min to 7 L / min and a high-speed pre-charge flow rate of 15 L / min. Simulation calculations were performed, and the simulation results were observed.

[0042] The streamline diagram of rapid pre-filling with crystalloid solution under high-speed flow impact (15 L / min) is shown below. Figure 2 and Figure 3 As shown, the streamlines preferentially diverge towards the four corners.

[0043] like Figure 4 The diagram shows the pressure distribution near the inlet of the oxygenation section. It can be seen that the edge pressure is higher. This high pressure reduces the size of bubbles trapped in the oxygenation membrane filaments, making them easier for the crystal liquid to flush away. This verifies that the design of this embodiment can quickly pre-fluff and reach all four corners. The velocity distribution near the inlet of the oxygenation section is shown below. Figure 5 As shown, the flow velocity is high around the edges and low in the middle.

[0044] When the oxygenator is in normal working condition and blood is being injected, the blood flow rate will not exceed 7 L / min. The streamline diagram under this condition is as follows: Figure 6 As shown, the blood quickly turns and enters the oxygenation zone after injection, without lingering in the inlet section. The pressure distribution near the inlet section of the oxygenation zone is basically uniform with no significant difference; the flow velocity difference is small, and the flow velocity distribution is as follows... Figure 7 As shown, the time it takes for blood to travel through the oxygenation zone (the time the blood is in contact with the oxygenation membrane filaments) is roughly uniform; moreover, the wall shear force on the blood is uniform throughout, and the blood will not be damaged due to excessive local wall shear force.

[0045] Optionally, under low-velocity laminar flow conditions, the resistance of porous media to the liquid is linearly related to the flow rate; under high-velocity turbulent flow conditions, it tends to be nonlinear. The linear relationship (laminar flow) is dominated by viscous forces and is governed by Darcy's equations: Q = (K * A * ΔP) / (μ * L); Where Q is the volumetric flow rate (m³ / s); ΔP is the pressure difference / pressure drop (Pa), representing the flow resistance; μ is the fluid dynamic viscosity (Pa·s); L is the length of the porous medium in the flow direction (m); A is the cross-sectional area (m²); and K is the permeability (approximately equal to porosity, in percentage).

[0046] Under high-speed turbulent conditions, inertial forces dominate, and the Forchheimer equations apply: -ΔP / L=(μ / K)*v+β*ρ*v²; Where v is the Darcy velocity (v = Q / A) (m / s); ρ is the fluid density (kg / m³); and β is the inertia coefficient (1 / m), which is another parameter describing the properties of porous media besides porosity. This equation contains two terms: the first term (μ / K)*v is the linear term of the Darcy equation, representing viscous drag; the second term β*ρ*v² is a newly added nonlinear term, representing inertial drag.

[0047] The above formula shows a strong negative correlation between the inertial coefficient β and the permeability K: the lower the permeability (the denser the medium), the earlier the inertial effect appears, and the larger the β value. Given that the oxygenator porosity is 0.5, the inertial coefficient β can be calculated using the Carman relation or experimentally measured, and is approximately 70,000 (1 / m). Tools such as MATLAB can be used to calculate the magnitude of viscous and inertial drag at different flow velocities, such as... Figure 8 As shown.

[0048] The reason for the small air bubbles becoming trapped at the four corners of the oxygenator is as follows: When the pre-filled fluid enters the oxygenation membrane wire area, the laminar flow velocity is low while the flow velocity in the center of the tubing is high. Typically, the central area is filled with pre-filled fluid first, and the four corners are filled last. When the flow velocity is low, viscous forces dominate, forming laminar flow. This laminar flow can break the air bubbles into tiny bubbles smaller than the diameter of the oxygenation membrane wire, which are then trapped by the laminar flow in the direction opposite to the streamlines, preventing them from being carried away by the flow. Medical staff usually create some disturbance by tapping the oxygenator to break the laminar flow's binding of the tiny bubbles and allow them to flow out.

[0049] Simulation experiments showed that when the flow rate reached 17 liters per minute, the inertial force exceeded the viscous force, quickly breaking the laminar flow's binding effect on the small bubbles. In reality, bench tests showed that the small bubbles could be rapidly expelled when the flow rate reached 9 liters per minute. This is because the viscous and inertial forces coexist, rather than undergoing a sudden transition.

[0050] Based on this principle, it is hoped that the oxygenator, in conjunction with the pump head, can use a high flow rate during the pre-filling stage to achieve the purpose of rapid pre-filling and venting, while under normal blood perfusion conditions, it will not cause greater damage to the blood due to reasons such as avoiding excessive shear force.

[0051] The design concept is as follows: First, it is assumed that the fluid flows uniformly, parallel, and in a laminar manner through the oxygenation section. Since the liquid is incompressible, its velocity is inversely proportional to its cross-sectional area. To avoid excessive fluid shear forces in localized areas, it is assumed that these streamlines do not have sharp turns (a larger turn is possible upon entering the oxygenation section due to sudden deceleration). This shape is very abstract, and a physical device called the streamline method can be used to assist in designing this structure. Specifically, 100 20cm long thin copper wires (solder wire can also be used, as it can be easily bent by hand and maintains its shape without springing back) are evenly inserted every 1cm into a 10cm × 10cm, 2cm thick foam board. Imagine these wires as streamlines, and then manually bend them to form a flow field model. All the thin copper wires are finally brought together, which is the blood inlet. According to oxygenator standards, the diameter of this inlet should be 3 / 8 inch (approximately 10mm), with a cross-sectional area equivalent to 72 square millimeters. That is, one thin copper wire is equivalent to a cross-sectional area of ​​0.07 square millimeters. When modeling a flow cavity, if a complex cross-section is encountered, the cross-sectional area can be estimated by counting the number of copper wires.

[0052] In this embodiment, as Figure 9 As shown, the approximate shape is determined by the turn-line method. Then, a model is created using relevant software, an STP file is generated by molding the flow cavity, the STP file is imported into a finite element fluid simulation tool, the fluid type, inlet parameters, and outlet parameters are set, and the simulation is started. The model is modified according to the simulation results until it meets the expectations.

[0053] like Figure 10 An example of flow field optimization, from Figure 10 It can be seen that the blood flow distribution in the four spiral arms is severely uneven. In region A, the flow velocity is high and the surrounding pressure difference is large, forming a reversible flow. Blood enters the oxygenation section and then flows back from the oxygenation zone to the inlet 2 cavity. In region B, the blood flow reaches the last shunt 402. As can be seen above, the blood flow in the first and second shunt 402 near inlet 2 is too large, while the blood flow in the third and fourth shunt 402 is insufficient.

[0054] Adjustment Methods: Without considering product aesthetics, directly adjust the cross-sectional area of ​​the rotating arms. For example, reduce the inner diameter of the first and second branch sections 402, and increase the inner diameter of the third and fourth branch sections 402 to directly adjust the flow rate of the four rotating arms. Considering product aesthetics, strive for a centrally symmetrical design for the four rotating arms. This can be achieved by adjusting the angle between the rotating arms and the tangent point of the central spiral tube; a larger angle results in a smaller flow rate, and a smaller angle results in a larger flow rate. However, simulations have shown that this adjustment is insufficient. Further, a flow-limiting baffle or protrusion can be added at the junction of the spiral section 401 and the first branch section 402, and at the junction of the spiral section 401 and the second branch section 402, respectively. This restricts blood flow, directly reducing the blood flow entering the rotating arms and forcing more blood into the third and fourth branch sections 402. The shape of this baffle has little impact on the wall shear force; the main factor is the difficulty of the mold design. For example, one-third or half of the junction of the rotating arms can be blocked.

[0055] CFD simulations and optimizations were continued for the optimized spiral section 401 and the diversion section 402 until the entire volute flow channel 4, under high-speed pre-filled liquid flow, could reach an angular position under inertia to achieve a good flushing effect; and the entire volute flow channel 4 would not produce abnormal blood flow phenomena under normal flow rate (e.g., below 7 liters per minute) blood flow conditions, ensuring that blood flows evenly through the membrane fiber region; it is understandable that when the liquid flow rate is low, the pressure difference between inlet 2 and outlet 3 is not large, the membrane fiber region (equivalent to porous media) is the main fluid resistance factor, and the liquid will basically flow evenly through the membrane fiber region.

[0056] Example 3: This embodiment provides a volute-type box-shaped laminated membrane oxygenator. Based on Embodiments 1 and 2, the entire membrane oxygenator is set to be without a temperature-changing structure. At this time, there is an annular bottom corner on the bottom edge of the box-shaped laminated structure 1, which makes the membrane oxygenator stand upright.

[0057] Example 4: This embodiment provides a volute-type box-shaped laminated membrane oxygenator. Based on Embodiments 1 and 2, the entire membrane oxygenator is configured with a variable temperature structure. Specifically, the variable temperature structure is designed such that the variable temperature water delivery pipe is parallel to the bottom edge of the box-shaped laminated structure 1, allowing it to stand upright when placed on a table.

[0058] Optionally, the variable temperature structure includes a water heater, a water pump connected to the water heater via a pipe, and a variable temperature delivery water pipe connected to the water pump. The variable temperature delivery water pipe is located at the bottom edge of the box-shaped stacked structure 1 to heat the blood. The variable temperature delivery water pipe may include multiple pipes, or a single variable temperature delivery water pipe may be arranged in a serpentine, loop, or spiral pattern at the bottom edge of the box-shaped stacked structure 1 to ensure the heating effect. The variable temperature delivery water pipe can circulate back to the heater, forming a closed loop, or it can flow into other hot water recovery equipment.

[0059] In some embodiments, the membrane oxygenator, in addition to the exhaust gas outlet, also includes a safety exhaust gas outlet. This safety outlet prevents the membrane fibers from bursting due to high-pressure oxygen when the exhaust gas outlet is blocked. Specifically, the exhaust gas outlet configuration on the membrane oxygenator is conventional and will not be detailed here. The safety exhaust gas outlet can be understood as an additional exhaust gas outlet located on the corresponding exhaust gas delivery pipe or other exhaust gas delivery structure, in a different position from the original exhaust gas outlet. Optionally, the safety exhaust gas outlet can be hidden between two variable-temperature water delivery pipes, or in a location less likely to be touched or blocked by fingers, such as the inner edge of the annular bottom corner.

[0060] The membrane oxygenator also includes an oxygen inlet equipped with an optional sensor to detect oxygen temperature. An optional sensor array is also installed at the exhaust outlet to detect exhaust gas flow rate, temperature, carbon dioxide content, and plasma leakage. Specifically, if the exhaust gas outlet temperature is lower than the inlet temperature, a malfunction is identified. Under normal circumstances, the oxygen, heated by the blood, should result in an exhaust gas temperature higher than the inlet temperature. If no carbon dioxide is present in the exhaust gas after the blood has passed through the oxygenator, it may indicate oxygenator failure or abnormal blood flow. A small amount of plasma leakage is permissible in some cases, but large amounts of plasma leakage (e.g., exceeding a preset value) or foaming should be addressed promptly.

[0061] In this embodiment, a support frame and a hanger mounted on the support frame are also provided. The hanger can move up and down on the support frame and is equipped with a hanging ring. Specifically, a hanging ring is provided on the square box stacked structure 1 near the oxygen inlet, which can be combined with the hook on the hanger to prevent swaying when suspended. It can be easily removed from the hanger. The hanger can be moved up and down on the support frame and locked. In the suspended state, the blood inlet and outlet of the oxygenator are horizontal, making it easy for medical personnel to observe the oxygenator and its tubing.

[0062] Example 5: This embodiment provides a volute-type box-shaped laminated membrane oxygenator, such as... Figure 11As shown, based on Embodiments 1 and 2, a flow-limiting part 403 is provided at the connection position between one or two diversion sections 402 and the spiral section 401 near the inlet 2 to reduce the flow rate entering the diversion section 402. The flow-limiting part 403 is a protrusion provided inside the diversion section 402, making the internal flow space smaller than other positions. The structural optimization of this embodiment is based on the following: First, simulation calculations were performed on the structure in Example 1 under inlet flow velocities of 0.4 m / s, 4 m / s, and 9 m / s, as shown in Table 1: Table 1 Simulated flow velocity and flow rate

[0063] This embodiment primarily observes for the presence of flow dead zones (to prevent thrombosis). Discussing pressure and flow rate at a flow rate of 0.4 m / s is not very meaningful; the flow rate and streamlines at a flow rate of 4 m / s are as follows: Figure 12 and Figure 13 As shown, the pressure distribution map shows a very small pressure difference, making the diagram unclear. It can be seen that under normal flow rates not exceeding 7 L / m, the flow field is uniform; simultaneously, examining the wall shear force confirms that there are no areas with high shear force.

[0064] At a flow rate of 9 m / s (high-speed pre-charged crystal solution), the flow rate and streamlines are as follows: Figure 14 and Figure 15 As shown, increasing the flow rate did not increase the flow rate at the four corners as envisioned in Embodiment 1. This is because the flow rate from the first branch section 402 near inlet 2 is too large, causing the flow to diffuse directly to the other four sides at a large angle. Therefore, in this embodiment, a flow-limiting section 403 is provided at the connection point between one or two branch sections 402 and the spiral section 401 near inlet 2 to reduce the flow rate entering the branch section 402. The protrusion that enables the flow-limiting section 403 to function is positioned opposite to the flow direction, not facing the flow direction. The size of the protrusion can be gradually approached to the ideal state through iterative modification-testing-modification-testing.

[0065] After adding the current limiting unit 403, such as Figure 16 and Figure 17 The diagrams shown are the flow rate diagram and streamline diagram for a flow velocity of 4 m / s; Figure 18 , Figure 19 and Figure 20 The diagram shows the flow rate, streamlines, and simulation results for a flow velocity of 9 m / s.

[0066] In summary, adding the flow restrictor 403 significantly enhances the flow rate at the four corners after increasing the flow velocity. Simulation results show that under normal operating flow rates, the streamlines pass through the oxygenation section almost parallel to each other; however, under high-speed pre-charge flow rates, the streamlines at the four corners exhibit radial diffusion, which helps the bubbles at the corner slits expand and be expelled by the liquid.

[0067] like Figure 21 and Figure 22 To determine the velocity distribution across the cross section of the spiral section 401 without adding the flow restrictor 403 and with the flow restrictor 403, Figure 21 It can be seen that although there is a speed difference between the outer and inner circumferences, Figure 22 The internal peripheral flow velocity is higher.

[0068] like Figure 23 , Figure 24 , Figure 25 and 26 As shown in this embodiment, in the box-shaped stacked structure 1, a comb-shaped flow channel 5 is provided on one side of the pipe connected to the outlet 3. The comb-shaped flow channel 5 includes multiple sub-flow channels of different lengths. The multiple sub-flow channels are symmetrically distributed on one side of the box-shaped stacked structure 1 connected to the pipe connected to the outlet 3, which enables blood at each location to flow out smoothly. The multiple sub-flow channels are all connected to the outlet 3 through a central flow channel 6.

[0069] Example 6: This embodiment provides a pre-filling method for a volute-type box-type laminated membrane oxygenator, which uses the volute-type box-type laminated membrane oxygenator as described in Embodiments 1, 2, 3, 4, or 5. The method includes: after the pre-filling liquid enters the spiral section 401 at the inlet 2, it flows to the diversion section 402 under the action of inertia. The pre-filling liquid flows through the diversion section 402 to the internal corner position of the box-type laminated structure 1 for flushing and air bubble discharge.

[0070] Optionally, a backup pump is used to pump the pre-filled liquid into inlet 2. After passing through the spiral section 401 and the diversion section 402, the pre-filled liquid flows to the internal corner of the square box stacked structure 1 for flushing. After pre-filling is completed, a working pump is used to pump blood into inlet 2. The pumped blood flows evenly through the membrane fiber area.

[0071] The above description is merely a preferred embodiment of this practice and is not intended to limit the scope of this practice. Various modifications and variations can be made to this practice by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this practice should be included within the protection scope of this practice.

Claims

1. A volute-type, box-shaped, laminated membrane oxygenator, characterized in that, It includes a box-shaped stacked structure, an inlet and an outlet disposed on the box-shaped stacked structure, and a volute-type flow channel connected to the inlet; The volute-type flow channel includes a spiral section and multiple branch sections; the input end of the spiral section is connected to the inlet; the input end of the branch section is connected to the spiral section, and the output end is located at the inner corner of the box-shaped stacked structure.

2. The volute-type box-shaped laminated membrane oxygenator as described in claim 1, characterized in that, The inlet is connected to a standby pump and a working pump. The standby pump can provide a liquid driving flow rate greater than that of the working pump. The cross-sectional dimension of the diversion section perpendicular to the liquid flow direction gradually decreases along the direction from the spiral section to the internal corner position of the box stack structure.

3. The volute-type box-shaped laminated membrane oxygenator as described in claim 1, characterized in that, At the connection points between the two shunt sections and the spiral section near the inlet of the membrane oxygenator, a flow-limiting part is provided. The flow-limiting part is a protrusion located outside the shunt section and is positioned in the opposite direction of the flow.

4. The volute-type box-shaped laminated membrane oxygenator as described in claim 1, characterized in that, The diversion section is configured as a flat slit structure, and the inner cross-section of the slit structure gradually decreases along the direction from the spiral section to the internal corner position of the square box stacked structure.

5. The volute-type box-shaped laminated membrane oxygenator as described in claim 4, characterized in that, At the connection between the spiral section and the diversion section, at least one of the inlets of the diversion section adopts an inclined elliptical hole, and the inclination angle of the diversion section inlet is equal to the spiral angle at the connection of the spiral section.

6. The volute-type box-shaped laminated membrane oxygenator as described in claim 5, characterized in that, In the aforementioned box-shaped stacked structure, a volute-type flow channel is provided on the side connecting the outlet, and the spiral section is connected to the outlet through a pipe; four slits are provided in the volute-type flow channel corresponding to the flow branch section.

7. The volute-type box-shaped laminated membrane oxygenator as described in claim 6, characterized in that, The diversion section is configured as a flat slit structure, and the inner cross section of the slit structure gradually decreases in size along the direction from the square box stacked structure to the spiral section; at the connection between the spiral section and the diversion section, at least one inlet of the diversion section adopts an inclined elliptical hole, and the inclination angle of the diversion section inlet is equal to the spiral angle at the connection of the spiral section.

8. The volute-type box-shaped laminated membrane oxygenator as described in claim 7, characterized in that, In the aforementioned box-shaped stacked structure, a comb-shaped flow channel is provided on one side of the outlet pipe. The comb-shaped flow channel includes multiple sub-flow channels of different lengths, which are symmetrically distributed on one side of the box-shaped stacked structure connected to the outlet pipe. All the sub-flow channels are connected to the outlet through a central flow channel.

9. A pre-filling method for a volute-type stacked membrane oxygenator, characterized in that, The membrane oxygenator with a volute-type box-shaped stacked structure as described in any one of claims 1-8 includes: after the pre-filled liquid enters the spiral section at the inlet, it flows to the diversion section under the action of inertia. The pre-filled liquid flows through the diversion section to the internal corner position of the box-shaped stacked structure for flushing and air bubble discharge.

10. The pre-filling method for a volute-type box-shaped laminated membrane oxygenator as described in claim 9, characterized in that, The pre-filled fluid is pumped into the inlet using a backup pump. After passing through the spiral section and the diversion section, the pre-filled fluid flows to the internal corner of the square box stacked structure for flushing. After pre-filling is completed, blood is pumped into the inlet using a working pump. The pumped blood flows evenly through the membrane fiber area.

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