Blood purification device and liquid level height adjusting method of gas-liquid separator thereof

Abstract

The application discloses a blood purification device and a liquid level height adjusting method of a gas-liquid separator thereof, and belongs to the technical field of medical devices. In the method, during a pre-flushing stage of a blood circuit, after a monitoring site downstream of the gas-liquid separator detects that liquid filling is completed (from air to no air), gas is filled into the gas-liquid separator to lower the liquid level thereof until the monitoring site detects bubbles again; subsequently, the downstream circuit is blocked and the gas in the gas-liquid separator is extracted to accurately raise the liquid level to a preset position. The application further discloses a blood purification device for realizing the method. The application utilizes the signal of a downstream bubble detector as feedback, realizes full-automatic and high-precision adjustment of the liquid level of a venous jug through two-step closed-loop control of "gas filling-gas extraction", does not need manual intervention, and effectively improves the safety and operation convenience of blood purification treatment.

Description

Technical Field

[0001] This invention belongs to the field of medical device technology, specifically a blood purification device and a method for adjusting the liquid level of its gas-liquid separator. It is applicable to blood purification equipment and is used to automatically adjust the liquid level in the venous reservoir (gas-liquid separator) during the pre-filling stage. Background Technology

[0002] Blood purification devices, such as hemodialysis machines, are essential medical equipment used to treat diseases such as kidney failure. Their working principle involves drawing the patient's blood out of the body, passing it through a blood purifier (such as a dialyzer) to remove metabolic waste and excess water, and then returning the purified blood to the patient. Before treatment begins, the extracorporeal blood circulation tubing (including arterial tubing, venous tubing, the blood purifier, and venous reservoir) must be pre-filled. The main purposes of pre-filling are: 1) to purge air from the tubing and blood purifier; 2) to fully wet the dialysis membrane inside the blood purifier to ensure optimal treatment results; and 3) to flush away any particles that may remain from the production and transportation process, reducing the patient's inflammatory response.

[0003] During the pre-filling process, adjusting the liquid level in the venous reservoir (also known as a gas-liquid separator or degassing reservoir) is a crucial step. The venous reservoir is typically located downstream of the blood purifier and is used to capture and separate any air bubbles that may be present in the blood, preventing air from entering the patient's body with venous blood backflow and thus avoiding serious medical accidents such as air embolism. Ideally, the liquid level should be maintained at approximately two-thirds of the reservoir's height. This effectively buffers and intercepts air bubbles while preventing venous pressure alarms due to excessively high liquid levels or air from entering downstream tubing due to excessively low liquid levels.

[0004] Currently, existing methods for adjusting the fluid level in venous urinals have the following limitations.

[0005] (1) Manual adjustment method: The operator uses a syringe to connect to the bypass port of the intravenous infusion vessel and manually injects or removes air to change the liquid level in the vessel. This process relies entirely on the operator's visual judgment and experience, which is cumbersome, time-consuming, and has poor adjustment accuracy, making it difficult to stably control the liquid level at the ideal position. In addition, manual operation increases the risk of contamination, and the operator cannot leave during the adjustment process.

[0006] (2) Semi-automatic auxiliary adjustment method: Some existing technologies disclose the installation of a liquid level monitoring unit (such as an ultrasonic sensor) and an air pump and other adjustment mechanisms on the equipment. When the liquid level monitoring unit detects that the liquid level is too high or too low, the equipment will issue an alarm or prompt. The operator still needs to manually trigger the air pump to perform inflation or deflation operations by pressing buttons or other means. Although this method eliminates the step of manually using a syringe, alarm and decision-making still require manual intervention, failing to achieve fully automatic closed-loop adjustment, and the control of the target liquid level position is still not precise enough.

[0007] (3) Direct control based on internal chamber sensors: Some existing technologies directly monitor the liquid level by setting multiple liquid level detection sensors (such as ultrasonic sensors) at different height positions (such as H1, H2) in the gas-liquid separator chamber, and control the liquid level based on the signals from these sensors. Although this method can achieve a certain degree of automatic control, it requires the precise installation of multiple sensors on the chamber, which increases the cost of consumables or equipment and the complexity of the structure. In addition, the target position of liquid level control is limited by the physical installation position of the sensors, which is not flexible and cannot be finely adjusted for different specifications of tubing or different clinical needs; in addition, there is also liquid splashing or wall adhesion in the gas-liquid separator chamber, which affects the detection of the liquid level sensor and is prone to misjudgment of the actual liquid level height.

[0008] In summary, existing technologies for adjusting the liquid level of gas-liquid separators during the pre-charging stage generally suffer from problems such as low automation, reliance on manual operation, poor adjustment accuracy, high cost, or complex control logic.

[0009] Therefore, there is an urgent need for a fully automated, high-precision, low-cost, and easy-to-operate method for adjusting the liquid level in a gas-liquid separator, as well as a corresponding blood purification device, to improve the efficiency and safety of blood purification therapy. Summary of the Invention

[0010] In view of this, the purpose of the present invention is to provide a blood purification device and a method for adjusting the liquid level of the gas-liquid separator, which aims to solve the problems of cumbersome operation and low efficiency caused by the need for manual monitoring and adjustment of the venous reservoir liquid level in the existing pre-filling stage, so as to achieve fully automated and intelligent control of liquid level adjustment and improve treatment safety and convenience.

[0011] To achieve the above objectives, the present invention provides the following technical solution: This invention first proposes a blood purification device, comprising: Blood circuits are used to circulate a patient's blood outside the body; A gas-liquid separator, installed in the blood circuit, is used to separate air bubbles from medical fluids or blood; A bubble detector is installed in the blood circuit downstream of the gas-liquid separator to detect whether there are bubbles in the blood circuit. A flow-blocking clamp is installed in the blood circuit downstream of the bubble detector to control the on / off state of the blood circuit at that location. A liquid level regulating component, connected to the gas-liquid separator, is used to adjust the liquid level inside it; The control unit is configured as follows: During the pre-filling stage of the blood circuit, when the bubble detector detects that the blood circuit changes from an air-containing state to an air-free state, the liquid level regulating component controls the gas-liquid separator to fill gas to reduce its liquid level height until the bubble detector detects that the blood circuit changes from an air-free state to an air-containing state again. Then, the flow-blocking clamp is controlled to block the blood circuit, and the liquid level regulating component is controlled to extract the gas in the gas-liquid separator so that the liquid level rises to a preset position.

[0012] Furthermore, the method for raising the liquid level of the gas-liquid separator to a preset position is as follows: based on the preset target liquid level position, calculate the volume of gas required to adjust the liquid level in the bubble detector to the target position; extract the required volume of gas from the gas-liquid separator, and precisely adjust the liquid level of the gas-liquid separator to the target position.

[0013] Furthermore, the preset target position for the liquid level is at 2 / 3 of the height of the gas-liquid separator.

[0014] Furthermore, the required gas extraction volume is the sum of 2 / 3 of the inherent volume of the gas-liquid separator and the volume of the pipeline between the lower end of the gas-liquid separator and the flow-blocking clamp.

[0015] Furthermore, controlling the liquid level regulating component to extract gas from the gas-liquid separator to raise its liquid level to a preset position specifically involves: calculating the theoretical operating time of the liquid level regulating component based on its fixed exhaust speed; controlling the liquid level regulating component to operate at the fixed exhaust speed based on the theoretical operating time to precisely adjust the liquid level in the gas-liquid separator to the target position, using the following formula: The theoretical operating time of the liquid level regulating component is:

[0016] in: This is the theoretical operating time required for the liquid level regulating component; The fixed exhaust speed of the liquid level regulating component; The volume from the flow-blocking clamp to 2 / 3 of the height of the gas-liquid separator; and:

[0017] in: This indicates the volume of the gas-liquid separator; The volume is the distance from the lower end of the gas-liquid separator to the flow-blocking clamp.

[0018] Furthermore, the control unit or bubble detector is configured to: determine that bubbles exist in the blood circuit if the bubble detector detects a single bubble with a volume of not less than 0.01 ml or a series of tiny bubbles with a volume of not less than 0.0001 ml in the blood circuit; otherwise, determine that bubbles do not exist in the blood circuit.

[0019] Furthermore, the liquid level regulating assembly includes a regulating pump, a pressure sensor, and a three-way solenoid valve; the three-way solenoid valve is used to selectively connect the pressure monitoring branch of the gas-liquid separator to the regulating pump or the pressure sensor; when gas is introduced into or extracted from the gas-liquid separator, the three-way solenoid valve connects the pressure monitoring branch to the regulating pump, and the liquid level regulating assembly includes an atmospheric vent valve; by opening the atmospheric vent valve and simultaneously controlling the flow clamp to block the downstream blood circuit, the liquid level in the gas-liquid separator is increased.

[0020] Furthermore, it also includes a blood pump installed on the blood circuit; while the control unit controls the liquid level regulating component to extract gas from the gas-liquid separator, the blood pump is simultaneously turned on to drive medical fluid to flow into the gas-liquid separator.

[0021] Furthermore, the blood purification device must satisfy at least one of the following conditions: 1) It also includes a gas-liquid separator base; the gas-liquid separator base is provided with a mounting groove for installing the gas-liquid separator, the mounting groove being a conical groove adapted to the gas-liquid separator; 2) It also includes a gas-liquid separator base; the gas-liquid separator base and the gas-liquid separator are respectively provided with first marking lines, and the installation position of the gas-liquid separator in the gas-liquid separator base is determined by aligning the two first marking lines. 3) The bubble detector and the blood circuit downstream of the gas-liquid separator are respectively provided with second marking lines. The installation position of the bubble detector on the blood circuit downstream of the gas-liquid separator is determined by aligning the two second marking lines.

[0022] This invention also proposes a method for adjusting the liquid level in a gas-liquid separator, applied to the blood purification device described above, comprising the following steps: During the pre-filling stage of the blood circuit, when the monitoring point located downstream of the gas-liquid separator detects that the state in the blood circuit has changed from having air to not having air, gas is introduced into the gas-liquid separator to lower its liquid level until the monitoring point detects that the state in the blood circuit has changed from not having air to having air. The blood circuit downstream of the monitoring site is blocked, and the gas in the gas-liquid separator is extracted, causing the liquid level in the gas-liquid separator to rise to a preset position.

[0023] Furthermore, the blood purification device includes a bubble detector installed at the monitoring site, which is used to detect whether bubbles exist in the blood circuit at the monitoring site.

[0024] Furthermore, the method for detecting whether there are bubbles in the blood circuit using the bubble detector is as follows: if the bubble detector detects a single bubble with a volume of not less than 0.01 ml or a series of tiny bubbles with a volume of not less than 0.0001 ml in the blood circuit, then it is determined that there are bubbles in the blood circuit; otherwise, it is determined that there are no bubbles in the blood circuit.

[0025] Furthermore, the method for raising the liquid level of the gas-liquid separator to a preset position is as follows: based on the preset target liquid level position, calculate the volume of gas to be extracted from the monitoring point to adjust the liquid level to the target position; extract the required volume of gas from the gas-liquid separator to precisely adjust the liquid level of the gas-liquid separator to the target position.

[0026] Furthermore, the liquid level adjustment component includes an adjustment pump; the method for precisely adjusting the liquid level of the gas-liquid separator to the preset position is as follows: calculating the theoretical operating time of the adjustment pump based on the fixed exhaust speed of the adjustment pump; controlling the adjustment pump to operate at the fixed exhaust speed based on the theoretical operating time, thereby precisely adjusting the liquid level of the gas-liquid separator to the target position.

[0027] The beneficial effects of this invention are as follows: The blood purification device of the present invention has the following technical effects: (1) Fully automatic closed-loop control: Unlike manual adjustment or semi-automatic assistance, this invention uses the signal of the downstream bubble detector as direct feedback, and the control unit automatically performs the two-step operation of "inflating-detecting-evacuating". No manual visual inspection or intervention is required throughout the process, realizing the complete automation of liquid level adjustment; (2) High precision and repeatability: By using the presence or absence of air at the monitoring point on the downstream side of the gas-liquid separator as the precise boundary for liquid level calibration, and combining the flow-blocking clamp and quantitative air extraction based on the pump displacement, the liquid level can be accurately and stably set at the preset position, overcoming the drawback of relying on visual estimation in the traditional method. (3) Improve treatment safety and efficiency: This invention can effectively prevent the risk of air entering the patient's body due to low liquid level, and avoid coagulation or pressure alarm caused by high liquid level; at the same time, the automated adjustment process greatly shortens the preparation time of the pre-flush stage and reduces the workload of medical staff.

[0028] In summary, the blood purification device of the present invention solves the problems of cumbersome operation, poor accuracy, and low efficiency caused by the need for manual monitoring and adjustment of the venous reservoir level during the pre-filling stage. It can also achieve fully automated, precise measurement and intelligent control of the fluid level adjustment, thereby improving the safety and convenience of treatment. Attached Figure Description

[0029] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the following figures are provided for illustration: Figure 1 This is the pipe connector for the blood purification device of the present invention during pre-charging; Figure 2 This is the pipe connector for the gas-liquid separator.

[0030] Explanation of reference numerals in the attached figures: 1-Blood circuit; 11-Arterial side blood circuit; 12-Venous side blood circuit; 2-Blood pump; 3-Blood purifier; 4-Gas-liquid separator; 41-Pressure monitoring branch; 42-Three-way solenoid valve; 43-Regulating pump; 44-Pressure sensor; 45-Post-dilution branch; 46-Atmospheric venting valve; 5-Bubble detector; 6-Flow clamp; 7-Waste bag; 8-Saline tubing clamp. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0032] like Figure 1 As shown, in at least one embodiment, the blood purification device mainly includes a blood circuit 1, a blood pump 2, a hemodialyzer 3, a gas-liquid separator 4, a bubble detector 5, a flow-blocking clamp 6, a liquid level regulating component, and a control unit.

[0033] Specifically, blood circuit 1 includes an arterial side blood circuit 11 and a venous side blood circuit 12. A blood pump 2 is installed on the arterial side blood circuit 11 to power the flow of blood or pre-filled fluid. A hemodialysis machine 3, used for purifying blood, is installed between the arterial side blood circuit 11 and the venous side blood circuit 12. That is, the blood circuit 1 upstream of the hemodialysis machine 3 is the arterial side blood circuit 11, and the blood circuit 1 downstream of the hemodialysis machine 3 is the venous side blood circuit 12.

[0034] In at least one embodiment, the gas-liquid separator 4 is a venous reservoir, installed on the venous side blood circuit 12. For example... Figure 2 As shown, a pressure monitoring branch 41 is provided on the upper part of the gas-liquid separator 4. One end of the pressure monitoring branch 41 is connected to the gas chamber of the gas-liquid separator 4, and the other end is connected to the first port of the three-way solenoid valve 42.

[0035] In at least one embodiment, the liquid level regulating assembly includes a three-way solenoid valve 42, a regulating pump 43, and a pressure sensor 44. Specifically, in this embodiment: the first port of the three-way solenoid valve 42 is connected to the pressure monitoring branch 41; the second port of the three-way solenoid valve 42 is connected to the pressure sensor 44 via a pipeline for monitoring the pressure inside the gas-liquid separator 4; and the third port of the three-way solenoid valve 42 is connected to the pumping port of the regulating pump 43 via a pipeline. In this embodiment, the regulating pump 43 is preferably a peristaltic pump, capable of precisely controlling the amount of gas inhaled or exhaled. Furthermore, the gas-liquid separator 4 in this embodiment is also provided with a post-dilution branch 45 for replenishing replacement fluid to the blood during treatment. Of course, the three-way solenoid valve 42 in this embodiment is only an example, and can also be replaced by a structure with a first branch equipped with a conventional solenoid valve, a second branch equipped with a solenoid valve with the first branch connected to the gas-liquid separator 4, and the second branch connected to both the gas-liquid separator 4 and the regulating pump 43.

[0036] In a preferred embodiment, the liquid level regulating component further includes an atmospheric opening valve 46. Specifically, by opening the atmospheric opening valve 46 and simultaneously controlling the flow-blocking clamp to block the downstream blood circuit, the liquid level in the gas-liquid separator is increased; preferably, a filter screen can also be installed at the atmospheric opening valve 46 to filter the air entering the liquid level regulating component or the gas-liquid separator 4 (filtering dust or bacteria, etc.) to improve treatment safety.

[0037] In the venous blood circuit 12, a bubble detector 5 and a flow-blocking clamp 6 are sequentially arranged along the direction of fluid flow (i.e., from the gas-liquid separator 4 to the patient end). The bubble detector 5 is used to detect the presence of air bubbles in the tubing. The flow-blocking clamp 6 is used to controllably open or close the venous blood circuit 12.

[0038] Specifically, in this embodiment, the method for detecting whether there are bubbles in the blood circuit using the bubble detector 5 is as follows: if the bubble detector 5 detects a single bubble with a volume of not less than 0.01 ml or a series of tiny bubbles with a volume of not less than 0.0001 ml in the blood circuit 1, then it is determined that there are bubbles in the blood circuit; otherwise, it is determined that there are no bubbles in the blood circuit. Of course, the bubble detection judgment standard here is an exemplary judgment method of this embodiment. Any substitutions or modifications made by those skilled in the art based on the concept or logic of this judgment standard should be considered within the protection scope of this invention.

[0039] The blood purification device in this embodiment also includes a gas-liquid separator seat (in this embodiment, a venous chamber seat, not shown in the figure). Specifically, to precisely control the installation position of the gas-liquid separator 4 on the gas-liquid separator seat, the following two methods can be adopted: First, a mounting groove for installing the gas-liquid separator 4 is provided on the gas-liquid separator seat, and the mounting groove is designed to fit the gas-liquid separator 4 (not shown in the figure), for example, it can be set to an inverted cone shape, or the outer wall of the gas-liquid separator can be set to an inverted cone shape; thus, the installation position of the gas-liquid separator 4 on the gas-liquid separator seat can be positioned by the matching and limiting between the gas-liquid separator 4 and the mounting groove. Second, first marking lines (not shown in the figure) are respectively provided on the gas-liquid separator seat and the gas-liquid separator 4, and the installation position of the gas-liquid separator 4 within the gas-liquid separator seat is determined by aligning the two first marking lines. Specifically, only one of the first and second methods can be used, or both can be used simultaneously, both achieving the technical objective of precisely controlling the installation position of the gas-liquid separator 4 on the gas-liquid separator seat.

[0040] In a preferred embodiment of this example, second marker lines (not shown in the figure) can be respectively set on the blood circuit 1 downstream of the bubble detector 5 and the gas-liquid separator 4. The installation position of the bubble detector 5 on the blood circuit 1 downstream of the gas-liquid separator 4 is determined by aligning the two second marker lines.

[0041] In this embodiment, the control unit (not shown in the figure) is configured to execute the gas-liquid separator liquid level adjustment method, including the following steps: blood circuit 1 pre-charging stage, when the monitoring point set downstream of the gas-liquid separator 4 detects that the state in the blood circuit changes from having air to not having air, gas is charged into the gas-liquid separator 4 to lower the liquid level of the gas-liquid separator 4 until the monitoring point detects that the state in the blood circuit 1 changes from not having air to having air; the blood circuit downstream of the monitoring point is blocked, and the gas in the gas-liquid separator 4 is extracted to raise its liquid level to a preset position.

[0042] In this embodiment, a bubble detector 5 is installed at the monitoring site on the blood circuit 1, that is, the location of the bubble detector 5 is the monitoring site.

[0043] Specifically, in the step of filling the gas-liquid separator 4 with gas to lower its liquid level, air is injected into the gas-liquid separator 4 through the liquid level regulating component, so that the blood circuit between the gas-liquid separator 4 and the monitoring point is filled with gas.

[0044] Specifically, in the step of extracting gas from the gas-liquid separator 4 to raise its liquid level to a preset position, the volume of gas required to be extracted from the bubble detector 4 (monitoring point) to adjust the liquid level to the target position is calculated based on the preset target liquid level. The required volume of gas is then extracted from the gas-liquid separator 4 to precisely adjust the liquid level of the gas-liquid separator 4 to the preset position. Figure 2 As shown, by using the presence or absence of air at the monitoring point downstream of the gas-liquid separator as the precise boundary for liquid level calibration, and given that the volume of the blood circuit segment from the flow-blocking clamp to the preset position is relatively constant, only a preliminary test is needed to accurately and stably set the liquid level at the preset position. The corresponding parameters can be obtained through measurement, including but not limited to the volume of the blood circuit segment or how to control the liquid level adjustment component to extract gas from the gas-liquid separator so that the liquid level accurately and stably reaches the preset position. Specifically, in this embodiment, the preset target liquid level height is 2 / 3 of the height of the gas-liquid separator 4. The required gas extraction volume is the sum of 2 / 3 of the inherent volume of the gas-liquid separator 4 and the volume of the pipeline from the lower end of the gas-liquid separator 4 to the flow-blocking clamp 6. In this embodiment, the method for accurately adjusting the liquid level of the gas-liquid separator 4 to the target position is as follows: calculate the theoretical operating time of the regulating pump 43 based on its fixed exhaust speed; control the regulating pump 43 to operate at a fixed exhaust speed based on the theoretical operating time, thereby accurately adjusting the liquid level of the gas-liquid separator 4 to the target position.

[0045] Specifically, the process of adjusting the liquid level in the gas-liquid separator in this embodiment is as follows.

[0046] I. Preparation Stage During pre-filling, the operator installs the tubing as usual, attaching the gas-liquid separator 4 to the equipment mounting bracket. The pressure monitoring branch 41 is connected to the regulating pump 43 or pressure sensor 44 via a three-way solenoid valve 42. The blood tubing at the lower end of the gas-liquid separator 4 is correctly installed into the bubble detector 5 and the flow clamp 6. The saline tubing clamp 8 is opened (currently, saline is the commonly used medical fluid in the pre-filling stage of the blood circuit), and the blood pump 2 is started running forward at a low flow rate (e.g., 100 mL / min) to begin pre-filling the blood circuit. At this time, the flow clamp 6 is in the open position. The saline flows sequentially through the arterial side blood circuit 11, the hemodialyzer 3, and the gas-liquid separator 4, finally flowing into the waste bag 7.

[0047] During this process, the bubble detector 5, located downstream of the gas-liquid separator 4, monitors the status of the pipeline in real time. Initially, the blood circuit 1 is filled with air, which enters the waste liquid bag 7 through the gas-liquid separator 4. During this process, the bubble detector 5 detects the presence of air.

[0048] Under the power of the blood pump 2, the saline solution enters the gas-liquid separator 4. After a period of time, when the saline solution fills the blood circuit 1 and reaches the bubble detector 5, the bubble detector 5 detects that the blood circuit 1 has changed from an air-containing state to an air-free state.

[0049] II. Automatic Liquid Level Adjustment Process The control unit (not shown in the figure) continuously receives the detection signal from the bubble detector 5. When the detected signal changes from an air-containing state to an air-free state, the control unit determines that the saline solution has entered the gas-liquid separator 4 and filled the venous blood circuit 12, at which point the automatic liquid level adjustment program is activated.

[0050] Step 1: Forcefully lower the liquid level (air inflation step) The control unit issues a command to switch the three-way solenoid valve 42 to a state where its first and third interfaces are connected, while simultaneously closing the connection with the pressure sensor 44, thus connecting the gas-liquid separator 4 to the regulating pump 43 via the three-way solenoid valve 42. Then, the regulating pump 43 is started, operating in a set first rotation direction (counter-clockwise in this embodiment) to inject air into the air chamber of the gas-liquid separator 4. As air is injected, the liquid level in the gas-liquid separator 4 begins to drop, and the liquid column in the previously liquid-filled venous blood circuit 12 falls back down. When the liquid level drops below the installation position of the bubble detector 5, the gas-liquid separator 4 is refilled with air until the signal from the bubble detector 5 changes from an air-containing state to an air-free state. At this point, the regulating pump 43 is stopped, and the space between the flow clamp 6 and the gas-liquid separator 4 is entirely filled with air. Specifically, when the regulating pump 43 is stopped, the controller controls the three-way solenoid valve 42 to connect the gas-liquid separator 4 to the pressure sensor 44.

[0051] Step 2: Precisely adjust the liquid level (vacuuming step) The control unit closes the flow-blocking clamp 6 and controls the three-way solenoid valve 42 to reconnect the regulating pump 43 with the gas-liquid separator 4, causing the regulating pump 43 to operate in the set second rotation direction (clockwise in this embodiment) to draw air from the gas chamber of the gas-liquid separator 4. As the air is drawn out, the liquid level in the gas-liquid separator 4 begins to rise steadily. When the liquid level rises to the preset position of the gas-liquid separator 4 (2 / 3 of the height of the gas-liquid separator 4 in this embodiment), the regulating pump 43 stops. Specifically, the first rotation direction is opposite to the second rotation direction. Specifically, while controlling the liquid level regulating component to draw gas from the gas-liquid separator 4, the blood pump 2 is simultaneously turned on to drive medical fluid into the gas-liquid separator 4. Of course, it is also possible to adjust the height of the gas-liquid separator 4 without turning on the blood pump 2, for example, by using a more efficient or higher-performance liquid level regulating component or regulating pump, or at least in this step, by disconnecting the pump tubing or the portion of the blood circuit that is connected to the blood pump from the blood pump.

[0052] To obtain a more precise liquid level (e.g., the liquid level is at 2 / 3 of the height of the gas-liquid separator 4), the control unit can calculate the theoretical operating time required for the regulating pump 43 based on pre-stored pipeline volume parameters and the displacement per revolution of the regulating pump 43. This allows for precise control of the pumping volume, ensuring the liquid level reaches the preset 2 / 3 height position. Specifically, the theoretical operating time required for the regulating pump 43 is:

[0053] in: To adjust the theoretical operating time required for pump 43; To adjust the displacement per revolution of pump 43 The unit is ml / s. This value is an inherent property of peristaltic pumps and, once solidified, will not change significantly. There are 6 flow-blocking clamps ( ) to 2 / 3 height of the gas-liquid separator ( The volume of () is calculated as follows:

[0054] in: This indicates the volume of gas-liquid separator 4 in ml. This value is an inherent property of gas-liquid separator 4 and will not change significantly. From the lower end of gas-liquid separator 4 to the flow-blocking clamp 6 ( The volume of the blood tubing is measured in ml. This value is related to the position of the gas-liquid separator 4 to the flow clamp when the operator installs the blood tubing. It is generally between 2 ml and 7 ml and can be considered a constant.

[0055] Step 3: End the adjustment Once the liquid level reaches the predetermined position, the control unit stops adjusting the pump 43, and the controller controls the three-way solenoid valve 42 to connect the gas-liquid separator 4 with the pressure sensor 44 so as to monitor venous pressure in subsequent treatment.

[0056] After the regulating pump 43 in the liquid level regulating assembly stops, the automatic liquid level regulation process of the gas-liquid separator 4 ends. Through the above two-step closed-loop control, this embodiment requires no manual intervention. It only uses the "presence or absence of air" binary signal from the downstream bubble detector 5 as feedback, combined with the blocking operation of the flow clamp 6, to accurately and stably set the liquid level in the gas-liquid separator 4 at the preset position. This embodiment not only has a high degree of automation and fast adjustment speed, but also has an accuracy far exceeding human judgment, effectively avoiding the treatment risks caused by improper liquid level. At the same time, since the pressure sensor 44 is selectively connected through the three-way solenoid valve 42 and is isolated during the liquid level regulation process, its monitoring value will not fluctuate due to the inflation and deflation operation, thereby ensuring the accuracy of venous pressure monitoring.

[0057] The above-described embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. A blood purification device, characterized in that, include: Blood circuits are used to circulate a patient's blood outside the body; A gas-liquid separator, installed in the blood circuit, is used to separate air bubbles from medical fluids or blood; A bubble detector is installed in the blood circuit downstream of the gas-liquid separator to detect whether there are bubbles in the blood circuit. A flow-blocking clamp is installed in the blood circuit downstream of the bubble detector to control the on / off state of the blood circuit at that location. A liquid level regulating component, connected to the gas-liquid separator, is used to adjust the liquid level inside it; The control unit is configured as follows: During the pre-filling stage of the blood circuit, when the bubble detector detects that the blood circuit changes from an air-containing state to an air-free state, the liquid level regulating component controls the gas-liquid separator to fill gas to reduce its liquid level height until the bubble detector detects that the blood circuit changes from an air-free state to an air-containing state again. Then, the flow-blocking clamp is controlled to block the blood circuit, and the liquid level regulating component is controlled to extract the gas in the gas-liquid separator so that the liquid level rises to a preset position.

2. The blood purification device according to claim 1, characterized in that, The method for raising the liquid level of the gas-liquid separator to a preset position is as follows: based on the preset target liquid level position, calculate the volume of gas to be extracted from the bubble detector to adjust the liquid level to the target position; extract the required volume of gas from the gas-liquid separator to precisely adjust the liquid level of the gas-liquid separator to the target position.

3. The blood purification device according to claim 2, characterized in that, The preset target position for the liquid level is at 2 / 3 of the height of the gas-liquid separator.

4. The blood purification device according to claim 3, characterized in that, The required gas extraction volume is the sum of 2 / 3 of the inherent volume of the gas-liquid separator and the volume of the pipeline between the lower end of the gas-liquid separator and the flow-blocking clamp.

5. The blood purification device according to claim 4, characterized in that, The process of controlling the liquid level regulating component to extract gas from the gas-liquid separator to raise the liquid level to a preset position involves: calculating the theoretical operating time of the liquid level regulating component based on its fixed exhaust speed; and controlling the liquid level regulating component to operate at the fixed exhaust speed based on the theoretical operating time to precisely adjust the liquid level in the gas-liquid separator to the target position. The specific formula is as follows: The theoretical operating time of the liquid level regulating component is: in: This is the theoretical operating time required for the liquid level regulating component; The fixed exhaust speed of the liquid level regulating component; The volume from the flow-blocking clamp to 2 / 3 of the height of the gas-liquid separator; and: in: This indicates the volume of the gas-liquid separator; The volume is the distance from the lower end of the gas-liquid separator to the flow-blocking clamp.

6. The blood purification device according to any one of claims 1-5, characterized in that, The control unit or bubble detector is configured to determine that bubbles exist in the blood circuit if the bubble detector detects a single bubble with a volume of not less than 0.01 ml or a series of tiny bubbles with a volume of not less than 0.0001 ml in the blood circuit; otherwise, it is determined that bubbles do not exist in the blood circuit.

7. The blood purification device according to claim 5, characterized in that, The liquid level regulating assembly includes a regulating pump, a pressure sensor, and a three-way solenoid valve. The three-way solenoid valve is used to selectively connect the pressure monitoring branch of the gas-liquid separator to the regulating pump or the pressure sensor. When gas is introduced into or extracted from the gas-liquid separator, the three-way solenoid valve connects the pressure monitoring branch to the regulating pump. The liquid level regulating assembly includes an atmospheric vent valve. By opening the atmospheric vent valve and simultaneously controlling the flow clamp to block the downstream blood circuit, the liquid level in the gas-liquid separator can be increased.

8. The blood purification device according to any one of claims 1-5 or 7, characterized in that, It also includes a blood pump installed on the blood circuit; while the control unit controls the liquid level regulating component to extract gas from the gas-liquid separator, the blood pump is turned on at the same time to drive medical fluid to flow into the gas-liquid separator.

9. The blood purification device according to any one of claims 1-5 or 7, characterized in that, The blood purification device must meet at least one of the following conditions: 1) It also includes a gas-liquid separator base; the gas-liquid separator base is provided with a mounting groove for installing the gas-liquid separator, the mounting groove being a conical groove adapted to the gas-liquid separator; 2) It also includes a gas-liquid separator base; the gas-liquid separator base and the gas-liquid separator are respectively provided with first marking lines, and the installation position of the gas-liquid separator in the gas-liquid separator base is determined by aligning the two first marking lines. 3) The bubble detector and the blood circuit downstream of the gas-liquid separator are respectively provided with second marking lines. The installation position of the bubble detector on the blood circuit downstream of the gas-liquid separator is determined by aligning the two second marking lines.

10. A method for adjusting the liquid level in a gas-liquid separator, applied to the blood purification device as described in any one of claims 1-9, characterized in that, Includes the following steps: During the pre-filling stage of the blood circuit, when the monitoring point located downstream of the gas-liquid separator detects that the state in the blood circuit has changed from having air to not having air, gas is introduced into the gas-liquid separator to lower its liquid level until the monitoring point detects that the state in the blood circuit has changed from not having air to having air. The blood circuit downstream of the monitoring site is blocked, and the gas in the gas-liquid separator is extracted, causing the liquid level in the gas-liquid separator to rise to a preset position.

11. The method for adjusting the liquid level in a gas-liquid separator according to claim 10, characterized in that, The blood purification device includes a bubble detector installed at the monitoring site, which is used to detect whether air bubbles are present in the blood circuit at the monitoring site.

12. The method for adjusting the liquid level in a gas-liquid separator according to claim 11, characterized in that, The method for detecting the presence of air bubbles in the blood circuit using the air bubble detector is as follows: if the air bubble detector detects a single air bubble with a volume of not less than 0.01 ml or a series of tiny air bubbles with a volume of not less than 0.0001 ml in the blood circuit, then it is determined that air bubbles exist in the blood circuit; otherwise, it is determined that air bubbles do not exist in the blood circuit.

13. The method for adjusting the liquid level in a gas-liquid separator according to any one of claims 10-12, characterized in that, The method for raising the liquid level of the gas-liquid separator to a preset position is as follows: based on the preset target liquid level position, calculate the volume of gas to be extracted from the monitoring point to adjust the liquid level to the target position; extract the required volume of gas from the gas-liquid separator to precisely adjust the liquid level of the gas-liquid separator to the target position.

14. The method for adjusting the liquid level in a gas-liquid separator according to claim 13, characterized in that, The liquid level regulating component includes a regulating pump; the method for precisely adjusting the liquid level of the gas-liquid separator to the preset position is as follows: calculating the theoretical operating time of the regulating pump based on the fixed exhaust speed of the regulating pump; controlling the regulating pump to operate at the fixed exhaust speed based on the theoretical operating time, thereby precisely adjusting the liquid level of the gas-liquid separator to the target position.

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