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

Abstract

The application belongs to the technical field of extracorporeal membrane oxygenation, and provides a volute type square box laminated structure membrane oxygenator and a pre-charging method thereof. In the square box laminated structure membrane oxygenator, a volute type flow channel is arranged in the square box laminated structure, the volute type flow channel comprises a spiral section and a plurality of shunt sections, the input end of the shunt section is connected with the spiral section, and the output end is located at the internal corner position of the square box laminated structure. After the high-flow-rate pre-charging liquid enters the spiral section at the inlet, the pre-charging liquid flows to the shunt section under the high-speed inertia effect, preferentially flows to the internal corner position of the square box laminated structure, and the bubble discharge effect at the four corners of the square box laminated structure is ensured. In addition, by means of the cooperation of the volute type flow channel and the high-speed pre-charging liquid, the flushing capacity of each position in the membrane oxygenator is improved, the shaking and oscillation operations of the membrane oxygenator are not needed, the workload of medical staff is reduced, and the problem of damage to consumables caused by improper shaking and beating actions is avoided.

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.

[0006] 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;

[0007] 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.

[0008] 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 the cross-sectional area of the shunt segment; the cross-sectional area of the shunt segment is basically uniform.

[0009] Further, the two shunt segments near the inlet of the membrane lung oxygenator are provided with flow limiting parts at the connection positions with the spiral segment, the flow limiting parts are protrusions arranged outside the shunt segments; the protrusions are arranged at positions opposite to the flow direction.

[0010] 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.

[0011] Further, at the connection between the spiral segment and the shunt segment, the inlet of at least one shunt segment adopts an inclined elliptical hole, and the inclination angle of the inlet of the shunt segment is equal to the spiral angle at the connection between the spiral segment and the shunt segment.

[0012] 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 corresponding to the shunt segment.

[0013] 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 between the spiral segment and the shunt segment, the inlet of at least one shunt segment adopts an inclined elliptical hole, and the inclination angle of the inlet of the shunt segment is equal to the spiral angle at the connection between the spiral segment and the shunt segment.

[0014] 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; the plurality of sub-flow channels are all connected with the outlet through a concentrated flow channel.

[0015] To achieve the above object, the second aspect, the application also provides a spiral casing square box laminated structure membrane lung oxygenator pre-charging method, adopts the following technical scheme:

[0016] 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 includes: after the pre-charging liquid enters the spiral segment at the inlet, the pre-charging liquid flows to the internal corner position of the square box laminated structure under the action of inertia, the flow rate is high, and the flow line is in a diffusion shape, which is beneficial to bubble discharge.

[0017] Further, the pre-charging liquid is pumped into the inlet by the standby pump, and after the pre-charging liquid passes 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.

[0018] Compared with the prior art, the application has the following beneficial effects:

[0019] 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 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 enters the spiral segment at the inlet, the pre-charging liquid flows to the shunt segment under the action of high-speed inertia, 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 by means of the cooperation of the spiral casing flow channel and the high-speed pre-charging liquid, the flushing capacity 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.

[0020] 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; 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.

[0021] 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 along the shunt segment; the shunt segment guides the high-speed impact pre-charging liquid to the four-corner position of the oxygenator where small bubbles are prone to be left, 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 gaps.

[0022] 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 square box stacked structure, thereby achieving the effect of greater flow velocity closer to the four corners of the square box stacked structure, improving the flushing ability and bubble removal effect at the four corners of the square box stacked structure.

[0023] 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.

[0024] 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

[0025] 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.

[0026] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0027] Figure 2 This is a streamline diagram of high-speed flow impact in Embodiment 1 of the present invention;

[0028] Figure 3 This is a 3D streamline diagram of Embodiment 1 of the present invention;

[0029] Figure 4 This is a pressure distribution diagram near the inlet end of the oxygenation section in Embodiment 2 of the present invention;

[0030] Figure 5 This is a flow velocity distribution diagram near the inlet section of the oxygenation section in Embodiment 2 of the present invention;

[0031] 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;

[0032] Figure 7 This is a flow velocity distribution diagram near the inlet section of the oxygenation section in Embodiment 2 of the present invention;

[0033] Figure 8 This is a schematic diagram illustrating the relationship between viscous resistance and inertial resistance in Embodiment 2 of the present invention;

[0034] Figure 9 Design flow chart for embodiment 2 of the present invention;

[0035] Figure 10 Example of flow field optimization for embodiment 2 of the present invention;

[0036] Figure 11 Structural schematic diagram for embodiment 5 of the present invention;

[0037] Figure 12 Simulation flow diagram for embodiment 5 of the present invention without adding flow restriction at 4 m / s flow rate;

[0038] Figure 13 Simulation streamline diagram for embodiment 5 of the present invention without adding flow restriction at 4 m / s flow rate;

[0039] Figure 14 Simulation flow diagram for embodiment 5 of the present invention without adding flow restriction at 9 m / s flow rate;

[0040] Figure 15 Simulation streamline diagram for embodiment 5 of the present invention without adding flow restriction at 9 m / s flow rate;

[0041] Figure 16 Simulation flow diagram for embodiment 5 of the present invention after adding flow restriction at 4 m / s flow rate;

[0042] Figure 17 Simulation streamline diagram for embodiment 5 of the present invention after adding flow restriction at 4 m / s flow rate;

[0043] Figure 18 Simulation flow diagram for embodiment 5 of the present invention after adding flow restriction at 9 m / s flow rate;

[0044] Figure 19 Simulation streamline diagram for embodiment 5 of the present invention after adding flow restriction at 9 m / s flow rate;

[0045] Figure 20 Simulation schematic diagram for embodiment 5 of the present invention after adding flow restriction at 9 m / s flow rate;

[0046] Figure 21 Flow rate distribution of the spiral segment cross section when not adding flow restriction for embodiment 5 of the present invention;

[0047] Figure 22 Flow rate distribution of the spiral segment cross section when adding flow restriction for embodiment 5 of the present invention;

[0048] Figure 23 Outlet connecting flow passage schematic diagram for embodiment 5 of the present invention;

[0049] 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;

[0050] Figure 25 This is a simulated bottom streamline diagram of Embodiment 5 of the present invention after adding a comb-shaped flow channel;

[0051] Figure 26 This is a simulated overall streamline diagram of Embodiment 5 of the present invention after adding comb-shaped flow channels;

[0052] 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

[0053] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0054] 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.

[0055] Example 1:

[0056] 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.

[0057] 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 a fiber membrane other than PMP hollow fiber membrane.

[0058] The inlet 2 is arranged as a blood inlet for pumping blood in; the outlet 3 is arranged as a blood outlet for letting blood out; and the inlet 2 and the outlet 3 are connected with a pipeline for transporting blood. It can be understood that, in addition to the inlet 2 and the outlet 3 for pumping blood in and out, the square box stack structure 1 is also provided with an oxygen inlet, a waste gas outlet and other structures, a pipeline connection port and a pipeline, etc., which can be realized by conventional technology and will not be described in detail here.

[0059] It should be noted that, at present, when the membrane lung oxygenator is pre-charged to remove bubbles, the bubbles cannot be fully removed, especially for the membrane lung oxygenator with the square box stack structure, the pre-charging liquid has weak flushing ability at the four corners, and bubbles are most likely to remain. Not only does it take 5-10 minutes to flush the pipeline at a high flow rate, but also the membrane lung oxygenator needs to be shaken to assist in the removal of bubbles. Even so, after pre-charging, there are still small bubbles remaining in the pores of the membrane lung oxygenator, and the overall pre-charging time takes 10-20 minutes, and improper shaking and shaking actions can damage the consumables.

[0060] In view of the problem that the bubbles cannot be fully removed in the membrane lung oxygenator at present, in the embodiment, a volute flow channel 4 is arranged in the square box stack structure 1. Specifically, the volute flow channel 4 includes a spiral segment 401 connected with the inlet 2, and a plurality of shunt segments 402. The input end of each shunt segment 402 is connected with the spiral segment 401, and the output end of each shunt segment 402 extends to different internal corner positions of the square box stack structure 1. In addition, the input end can be understood as the position where the liquid enters the shunt segment 402; the output end is the corresponding position where the liquid flows out of the shunt segment 402; and the internal corner can be understood as the angle between the adjacent side walls in the square box stack structure 1, i.e. the position where the bubbles are difficult to remove.

[0061] The spiral segment 401 is in a spiral shape, and different shunt segments 402 are arranged at different positions of the spiral segment 401. During pre-charging, the pre-charging liquid is pumped in through the inlet 2 under the action of the standby pump. During the process of flowing through the spiral segment 401 at a high speed, the pre-charging liquid flows into each shunt segment 402 under the action of inertia, so as to reach each corner position in the square box stack structure 1, thereby achieving effective flushing of each corner position in the square box stack structure 1 and ensuring the effect of removing bubbles. At the same time, under the super-high flow rate of the pre-charging liquid, the gas in the entire square box stack structure 1 is quickly removed, the pre-charging time is shortened, and the pre-charging efficiency is improved.

[0062] In some embodiments, the square box stack structure 1 has four corners, and four shunt sections 402 are evenly distributed around the spiral section 401; of course, in other embodiments, the number of shunt sections 402 can be flexibly adjusted according to the number of internal corners of the square box stack structure 1, or according to the number of positions where bubbles are difficult to remove in other structure membrane oxygenators.

[0063] Optionally, the cross-sectional dimension of the shunt section 402 perpendicular to the liquid flow direction gradually decreases in the direction from the spiral section 401 to the internal corner position of the square box stack structure 1, that is, the closer to the corner position, the smaller the cross-sectional area allowed for fluid flow, achieving the purpose of faster flow rate closer to the four corners of the square box stack structure 1, and improving the flushing capacity and bubble removal effect at the four corners of the square box stack structure 1.

[0064] In some embodiments, the shunt section 402 can be provided as a flat slit structure, and the inner cross section of the slit structure gradually decreases in the direction from the spiral section 401 to the internal corner position of the square box stack structure 1, that is, the closer to the corner position, the smaller the cross-sectional area allowed for fluid flow, achieving the purpose of faster flow rate closer to the four corners of the square box stack structure 1; the flat slit structure of the shunt section 402 not only occupies less space and reduces the overall volume of the membrane oxygenator, but also has a larger contact length with the fluid, which can improve the heat transfer efficiency. The connection between the spiral section 401 and the shunt section 402 adopts an inclined elliptical hole form at least at the inlet of the shunt section 402, and the inclination angle of the inlet of the shunt section 402 is equal to or close to the spiral angle at the connection between the spiral section 401 and the shunt section 402, which is conducive to the smooth flow of liquid from the spiral section 401 to the shunt section 402.

[0065] In summary, by providing a membrane oxygenator with a special structure of the volute flow channel 4, and combining the function of the standby pump providing high flow rate pre-liquid, the speed of consumable pre-charging can be accelerated and the operation difficulty can be reduced under the premise of fully ensuring the safety of the structure and performance of the membrane oxygenator. Based on this, in the present embodiment, the inlet 2 is connected with a standby pump and a working pump, and the liquid driving flow rate provided by the standby pump is greater than that of the working pump; specifically, the standby pump can provide a larger liquid driving flow rate, which, in combination with the volute flow channel 4, ensures the pre-liquid flow rate and flushing effect; the working pump is used for pumping blood, and can ensure that the blood flows in the membrane oxygenator at a preset normal working flow rate.

[0066] The standby pump has higher reserve power, and specific working parameters can be adjusted and determined according to actual requirements. In one embodiment, the standby pump can reach a high speed of 9000 rpm per minute, and the driving perfusion pre-charge liquid reaches an ultra-high flow rate of 15 liters per minute, at which time the flow rate does not cause damage to the oxygenation membrane filaments in the membrane oxygenator parts. Optionally, a blood pump, a standby pump head, and a working pump head are provided, and the pre-charge operation is carried out by placing the blood pump on the standby pump head, and after the pre-charge is completed, the blood pump is moved to the working pump head, and the working pump head has a maximum flow rate of 7 liters per minute, and various automatic devices are combined to ensure that various parameters are within a safe range.

[0067] In some embodiments, the standby pump and the working pump are respectively connected with a pre-charge liquid storage device and a blood storage device; the standby pump and the working pump are connected in parallel through a pipeline and connected with the inlet; when pre-charge is needed, the standby pump works, the working pump does not work, and the pre-charge liquid is pumped into the box stack structure 1 through the standby pump for pre-charge; after the pre-charge is completed, the working pump works, the standby pump does not work, and the blood is pumped into the box stack structure 1 for normal work; the switching of pre-charge and blood pumping does not require manual intervention, and the efficiency is improved.

[0068] In some embodiments, one side of the box stack structure 1 connected with the outlet 3 pipeline is also provided with a volute flow channel, and the spiral segment 401 is connected with the outlet 3 through a pipeline; four wide slits are also arranged at the position corresponding to the shunt segment 402 in the volute flow channel, so as to reduce the blood outflow resistance of the four-corner area and make the flow field inside the membrane filament area more stable.

[0069] Specifically, the shunt segment 402 in the volute flow channel connected with the outlet 3 can also be provided as a flat slit structure, and the inner cross section of the slit structure gradually decreases in the direction from the box stack structure 1 to the spiral segment 401, that is, the closer to the spiral segment 401, the smaller the cross-sectional area allowed to flow through, so as to achieve the purpose of the flow rate being larger closer to the spiral segment 401; in addition to occupying a small space and reducing the overall volume of the membrane oxygenator, the flat slit structure has a larger contact length with the fluid, and the heat transfer efficiency can be improved. Similarly, at least one inlet of the shunt segment 402 at the connection between the spiral segment 401 and the shunt segment 402 adopts an inclined elliptical hole form, and the inclination angle of the inlet of the shunt segment 402 is equal to or close to the spiral angle at the connection of the spiral segment 401, which is beneficial to the smooth flow of the liquid from the shunt segment 402 to the spiral segment 401.

[0070] 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.

[0071] Example 2:

[0072] 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.

[0073] Optionally, the membrane oxygenator designed in this embodiment, including the volute-type flow channel 4, is subjected to simulation verification:

[0074] 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.

[0075] 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.

[0076] 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 blood flow rate is high in the periphery and low in the middle.

[0077] When the oxygenator is in normal working condition, the blood flow rate will not exceed 7 L / min. The streamline diagram under this condition is shown in Figure 6 As shown, the blood flow is quickly diverted into the oxygenation section after injection and does not spiral in the inlet section. The pressure distribution near the inlet section of the oxygenation section is basically uniform without significant differences; the flow rate difference is not large, and the flow rate distribution is shown in Figure 7 As shown, the time for the blood to pass through the oxygenation section (the time for the blood to contact the oxygenation membrane wire) is roughly uniform; and the wall shear force on the blood is uniform everywhere, and will not cause blood damage due to excessive local wall shear force.

[0078] Optionally, under low-speed laminar flow conditions, the resistance of the porous medium to the liquid is linearly related to the flow rate; under high-speed turbulent flow conditions, it tends to be nonlinear. The linear relationship (laminar flow) is dominated by viscous force, and is suitable for Darcy equation:

[0079] Q=(K*A*ΔP) / (μ*L);

[0080] Wherein, Q is the volume flow rate (m³ / s); ΔP: pressure difference / pressure drop (Pa), representing the flow resistance; μ: fluid dynamic viscosity (Pa·s); L: length of the porous medium in the flow direction (m); A: cross-sectional area (m²); K: permeability (approximately equal to porosity, unit: percentage).

[0081] Under high-speed turbulent flow conditions, it is dominated by inertial force, and is suitable for Forchheimer equation:

[0082] -ΔP / L=(μ / K)*v+β*ρ*v²;

[0083] Wherein, v is the Darcy flow rate (v = Q / A) (m / s); ρ is the fluid density (kg / m³); β is the inertial coefficient (1 / m), which is another parameter describing the characteristics of the porous medium in addition to the porosity. This equation contains two terms: the first term (μ / K)*v is the linear term of the Darcy equation, representing viscous resistance; the second term β*ρ*v² is a new nonlinear term, representing inertial resistance.

[0084] As shown by the above formula, the inertial coefficient β has a strong negative correlation with 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 relationship or measured through experiments, and is approximately 70000 (1 / m). The sizes of the viscous resistance and the inertial resistance under different flow rates can be calculated using tools such as matlab, as shown in Figure 8 .

[0085] The reason for the small bubble lodging in the four corners of the oxygenator: when the priming liquid enters the oxygenation membrane wire area, the wall-attached flow rate is low and the pipeline center flow rate is high, usually the middle position is first filled with priming liquid, and the four corner positions are last filled with priming liquid. When the flow rate is low, the viscous force dominates the formation of laminar flow, which can break the small bubbles into micro-bubbles smaller than the diameter of the oxygenation membrane wire, and bind the micro-bubbles in the position of the oxygenation membrane wire opposite to the streamline direction, and cannot be washed away with the flow. Medical staff usually create a certain disturbance by patting the oxygenator to break the binding of laminar flow to the micro-bubbles and let the bubbles flow out.

[0086] According to the simulation experiment, when the flow rate reaches 17 liters per minute, the effect of inertial force exceeds that of viscous force, which can quickly break the binding effect of laminar flow on small bubbles. In fact, through bench test, it is observed that when the flow rate reaches 9 liters per minute, small bubbles can be quickly discharged. This is because viscous force and inertial force coexist, not suddenly turn.

[0087] According to this principle, it is hoped that the oxygenator cooperates with the pump head to use a large flow rate in the priming stage to achieve the purpose of rapid priming and exhaust, and in the normal perfusion blood working condition, it will not cause greater harm to the blood due to avoiding excessive shear force and the like.

[0088] The design idea is that, first of all, it is assumed that the fluid passes through the oxygenation section uniformly, parallel to the oxygenation section, and in a laminar flow manner. Since the liquid is incompressible flow, its flow rate is inversely proportional to the cross-sectional area. In order to avoid causing excessive fluid shear force in a local part, it is assumed that the flow lines have no sharp turns (there can be a larger turn when entering the oxygenation section due to sudden deceleration). This shape is very abstract, and a physical device called the solenoid method can be used to assist in designing this structure. Specifically, 100 20 cm long thin copper wires (soldering wires can also be used, which can be easily bent by hand and can maintain the shape without rebounding) are inserted into a 10 cm x 10 cm thick foam plastic plate every 1 cm, and these thin wires are imagined as flow lines, and then the flow field model is manually bent. All the thin copper wires are finally gathered together, which is the blood inlet. According to the relevant standards of the oxygenator, the diameter of this inlet should be 3 / 8 inch (about 10 mm), and the cross-sectional area is equivalent to 72 square millimeters. That is, 1 thin copper wire is equivalent to a cross-sectional area of 0.07 square millimeters. When modeling the flow cavity, when a complex cross-section is encountered, the number of copper wires can be used to estimate the size of the cross-sectional area to be adopted.

[0089] In this embodiment, as Figure 9As shown, the approximate shape is determined by the winding method, then modeled with related software, and the stp file is generated by reverse modeling of the flow cavity. The stp file is imported into the 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 the desired result is achieved.

[0090] As Figure 10 For the example of flow field optimization, from Figure 10 It can be seen that the blood flow distributed by the four rotating arms is seriously uneven, with high flow rate in the A area and large peripheral pressure difference, forming a turning flow, blood entering the oxygenation section and flowing back to the inlet 2 cavity from the oxygenation area, and the B area being the last shunt section 402 where blood flow reaches. As known from the above, the first shunt section 402 and the second shunt section 402 near the inlet 2 have excessive blood flow, while the third shunt section 402 and the fourth shunt section 402 have insufficient blood flow.

[0091] Adjustment method: without considering the product aesthetics, directly adjust the cross-sectional area of the rotating arm, for example, reduce the inner diameter of the first shunt section 402 and the second shunt section 402, and enlarge the inner diameter of the third shunt section 402 and the fourth shunt section 402, to directly adjust the flow of the four rotating arms. Considering the product aesthetics, try to make the four rotating arms have a central symmetry aesthetic, and adjust the included angle of the rotating arm and the tangent position of the central spiral tube. The larger the included angle, the smaller the flow into the rotating arm, and the smaller the included angle, the larger the flow into the rotating arm. However, simulation proves that such adjustment is not enough. Further, a flow limiting baffle or a flow limiting protrusion can be added at the junction of the spiral section 401 and the first shunt section 402, and at the junction of the spiral section 401 and the second shunt section 402, respectively, to limit the blood flow and directly reduce the blood flow into the rotating arm, forcing more blood to flow into the third shunt section 402 and the fourth shunt section 402. The shape of this baffle has little effect on the wall shear force, mainly depending on the difficulty of mold design. For example, the rotating arm junction can be blocked by 1 / 3 or half.

[0092] The optimized spiral section 401 and shunt section 402 are continuously subjected to CFD simulation and optimization until the entire volute flow passage 4 can achieve the angular position under the action of inertia in the high-speed pre-liquid flow condition, achieving better flushing effect; and the entire volute flow passage 4 does not produce abnormal blood flow phenomenon under the blood flow condition of normal flow rate (such as less than 7 liters per minute), ensuring that the blood flows uniformly through the membrane filament area. It can be understood that when the liquid flow rate is low, the pressure difference between the inlet 2 and the outlet 3 is not large, and the membrane filament area (equivalent to a porous medium) is the main fluid resistance factor, and the liquid basically flows uniformly through the membrane filament area.

[0093] Example 3:

[0094] The embodiment provides a volute type square box laminated structure membrane lung oxygenator, on the basis of the embodiment 1 and the embodiment 2, the whole membrane lung oxygenator is arranged as not having a temperature changing structure, at this time, there is a ring-shaped bottom corner at the bottom edge of the square box laminated structure 1, so that the membrane lung oxygenator can stand upright.

[0095] Embodiment 4:

[0096] The embodiment provides a volute type square box laminated structure membrane lung oxygenator, on the basis of the embodiment 1 and the embodiment 2, the whole membrane lung oxygenator is arranged as not having a temperature changing structure, at this time, there is a ring-shaped bottom corner at the bottom edge of the square box laminated structure 1, so that the membrane lung oxygenator can stand upright.

[0097] Optionally, the temperature changing structure comprises a water heater, a water pump connected with the water heater through a pipeline, and a temperature changing water conveying pipe connected with the water pump; the temperature changing water conveying pipe is located at the bottom edge of the square box laminated structure 1 and heats blood, and the temperature changing water conveying pipe can comprise multiple pipes or one temperature changing water conveying pipe is arranged in a serpentine, a meander or a spiral shape at the bottom edge of the square box laminated structure 1, so as to ensure the heating effect; the temperature changing water conveying pipe can be recycled to the heater to form a closed loop as a whole, or can flow into other hot water recovery equipment.

[0098] In some embodiments, the membrane lung oxygenator is additionally provided with a safety waste gas outlet on the basis of the waste gas outlet, so that the problem of high-pressure oxygen blowing and exploding the membrane filament can be avoided when the waste gas outlet is blocked. Specifically, the waste gas outlet of the membrane lung oxygenator is a conventional technology, and will not be described here in detail, and the safety waste gas outlet can be understood as another waste gas outlet arranged on the waste gas conveying pipe or other waste gas conveying structure corresponding to the waste gas outlet, which is different from the position of the original waste gas outlet. Optionally, the safety waste gas outlet can be hidden in the middle of the two temperature changing water conveying pipes or the inner edge of the ring-shaped bottom corner and other places that are not easy to be touched by fingers and blocked.

[0099] The membrane lung oxygenator further comprises an oxygen inlet, and the oxygen inlet is provided with an optional sensor for detecting the temperature of oxygen. The waste gas outlet is also provided with an optional sensor group for detecting the flow, temperature, carbon dioxide content and plasma leakage of waste gas. Specifically, if the temperature of the waste gas outlet is lower than the temperature of the inlet, it is judged as a fault, and under normal circumstances, the temperature of the waste gas should be higher than the temperature of the inlet after the oxygen is heated by the blood; if there is no carbon dioxide in the waste gas after the blood flows through the oxygenator, it may mean that the oxygenator is ineffective or the blood flow state is abnormal. In some cases, a small amount of plasma leakage can be allowed, but a large amount of plasma leakage (for example, when the amount of plasma leakage is greater than a preset value) or foam gushing should be handled in time.

[0100] In this embodiment, a support is also provided, and a hanger is arranged on the support, the hanger being capable of moving up and down on the support, and a lifting ring is arranged on the hanger. Specifically, a lifting ring is arranged on the square box stack structure 1 at a position near the oxygen inlet, and can be combined with a hook on the hanger, so that the square box stack structure 1 does not swing when being hung. The square box stack structure 1 can be conveniently taken off from the hanger. The hanger can be moved up and down on the support and locked in position. In the hanging state, the blood inlet and outlet of the oxygenator are horizontal, which is convenient for medical staff to observe the oxygenator and its pipeline.

[0101] Embodiment 5

[0102] This embodiment provides a volute square box stack structure membrane lung oxygenator, as shown in Figure 11 on the basis of Embodiment 1 and Embodiment 2, a flow limiting part 403 is arranged at the position where one or two shunt sections 402 are connected to the spiral section 401, to reduce the flow entering the shunt section 402. The flow limiting part 403 is a protrusion arranged inside the shunt section 402, so that the internal flow space is smaller than other positions. The structure optimization of this embodiment is as follows:

[0103] Firstly, the structure in Embodiment 1 is simulated and calculated under the conditions of inlet flow rates of 0.4 m / S, 4 m / S and 9 m / S, respectively, as shown in Table 1:

[0104] Table 1 Simulation flow rate and flow

[0105]

[0106] This embodiment mainly observes whether there is a flow dead zone (to avoid thrombus) and the significance of pressure and flow under the condition of a flow rate of 0.4 m / S is not great; the flow and flow line under the condition of a flow rate of 4 m / S are shown in Figure 12 and Figure 13 respectively, and the pressure distribution diagram has a very small pressure difference, which is not obvious in the figure. It can be seen that under the condition of a normal flow rate of not more than 7 L / m, the flow field is uniform; at the same time, by checking the wall shear force, it is confirmed that there is no area to avoid high shear force.

[0107] The flow and flow line under the condition of a flow rate of 9 m / S (high-speed pre-charging crystalloid) are shown in Figure 14 and Figure 15As 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] Example 6:

[0113] The embodiment provides a volute square box laminated structure membrane lung oxygenator pre-charging method, adopts the volute square box laminated structure membrane lung oxygenator described in the embodiment 1, the embodiment 2, the embodiment 3, the embodiment 4 or the embodiment 5, and the method comprises the following steps: after pre-charging liquid enters the spiral section 401 through the inlet 2, the pre-charging liquid flows to the shunt section 402 under the action of inertia, the pre-charging liquid flows to the internal corner position of the square box laminated structure 1 through the shunt section 402, and flushing and bubble discharge are carried out.

[0114] Optionally, the pre-charging liquid is pumped into the inlet 2 by a standby pump, the pre-charging liquid flows to the internal corner position of the square box laminated structure 1 after passing through the spiral section 401 and the shunt section 402, and flushing is carried out; after pre-charging is completed, blood is pumped into the inlet 2 by using a working pump, and the pumped blood uniformly flows through the membrane filament area.

[0115] The above only provides preferred embodiments of the embodiment and is not used to limit the embodiment, and the embodiment can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiment shall be included in the protection scope of the embodiment.

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. 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.

2. 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.

3. 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.

4. The volute-type box-shaped laminated membrane oxygenator as described in claim 3, 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.

5. The volute-type box-shaped laminated membrane oxygenator as described in claim 4, 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.

6. 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 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.

7. The volute-type box-shaped laminated membrane oxygenator as described in claim 6, 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.

8. A pre-filling method for a volute-type stacked membrane oxygenator, characterized in that, The membrane oxygenator with a volute-type box-shaped laminated structure as described in any one of claims 1-7 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 laminated structure for flushing and air bubble discharge.

9. The pre-filling method for a volute-type box-shaped laminated membrane oxygenator as described in claim 8, characterized in that, The pre-filled liquid is pumped into the inlet by a backup pump. After passing through the spiral section and the diversion section, the pre-filled liquid flows to the internal corner of the box-shaped stacked structure for flushing.

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