Constant-pressure flow velocity testing device and method for medical catheter

Abstract

The invention relates to the technical field of medical equipment, in particular to a constant-pressure flow velocity testing device and method for a medical catheter.The constant-pressure flow velocity testing device for the medical catheter.The constant-pressure flow velocity testing device for the medical catheter.The constant-pressure flow velocity testing device for the medical catheter.The constant-pressure flow velocity testing device comprises a main control module, a first ultrasonic detection device, a second ultrasonic detection device and a flow adjusting mechanism; the first ultrasonic detection device, the second ultrasonic detection device and the flow adjusting mechanism are all in data connection with the main control module, and the detection portion of the first ultrasonic detection device, the detection portion of the flow adjusting mechanism and the detection portion of the second ultrasonic detection device are sequentially arranged. The first ultrasonic detection device and the second ultrasonic detection device are each provided with a measuring space for containing a medical catheter. According to the invention, a series of functions such as ultrasonic flow velocity testing of multiple detection points and pressure detection and adjustment in the medical catheter can be realized, the pressure difference caused by various factors in a long liquid path can be effectively reduced, the constant-pressure conveying function of the medical catheter can be realized, and the safety coefficient is high.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and particularly to a constant-pressure flow rate testing device and method for a medical catheter. Background Art

[0002] Medical catheters are medical devices widely used in the medical field and are used in various diagnostic and treatment procedures. They are designed to enter the blood vessels, cavities or other internal structures of the human body to deliver drugs, perform liquid drainage, monitor the internal environment or perform specific medical operations. During medical activities, especially during surgical operations, it is necessary to strictly control the liquid delivery of medical catheters. In some delicate surgical operations, not only the liquid flow rate needs to be precisely controlled, but also the pressure of the delivered liquid needs to be kept constant. Existing flow rate testing devices generally add a speed measurement device to the liquid path to improve the testing accuracy, which can provide accurate readings, but there are also certain risks. It is difficult to disinfect the precise speed measurement device, and the liquid in the medical catheter is easily affected by the residual pollutants in the speed measurement device during use. At the same time, adding a speed measurement device also increases the operation steps and is inconvenient to use. Also, during use, when using a medical catheter with a long length, the meandering liquid path will also cause differences in the flow rates of various parts, making it difficult to precisely control the flow rate and pressure of liquid delivery through a single speed measurement device. Summary of the Invention

[0003] The technical problem to be solved by the present invention: The existing flow rate testing method is not suitable for testing the liquid flow rate in medical catheters. The liquid in the medical catheter is easily contaminated during use, and the safety factor is relatively low. At the same time, the flow rate testing accuracy is relatively low, which is not conducive to precisely controlling the flow rate and pressure of liquid delivery.

[0004] In order to solve the above technical problems, the first aspect of the present invention adopts the following technical solutions: a constant pressure flow rate test device for a medical catheter, comprising a main control module, a first ultrasonic detection device, a second ultrasonic detection device and a flow regulating mechanism, wherein the first ultrasonic detection device, the second ultrasonic detection device and the flow regulating mechanism are all data-connected to the main control module, the detection position of the first ultrasonic detection device, the flow regulating mechanism and the detection position of the second ultrasonic detection device are arranged in sequence, the first ultrasonic detection device and the second ultrasonic detection device are both provided with a measuring space for loading the medical catheter, the first ultrasonic detection device outputs first flow rate information to the main control module after obtaining the liquid flow rate in the medical catheter through ultrasonic detection, the flow regulating mechanism works to output a matching flow after calculating the flow control information output by the first flow rate information through the main control module, the second ultrasonic detection device outputs second flow rate information to the main control module after obtaining the liquid flow rate in the medical catheter through ultrasonic detection, the main control module obtains a pressure value difference by calculating the first flow rate information and the second flow rate information and outputs a control signal to a corresponding liquid delivery device to adjust the pressure value in the medical catheter to a preset pressure value.

[0005] When the present invention is working, it can realize a series of functions such as ultrasonic flow velocity testing of multiple detection points, pressure detection and regulation in the medical catheter, etc., with a high degree of automation, suitable for long-distance liquid transportation, and can effectively reduce the pressure difference caused by various factors in a long liquid path, and can realize the constant pressure transportation function of the medical catheter. At the same time, it can avoid direct contact with the liquid in the medical catheter, avoid the occurrence of liquid contamination, and greatly improve the safety factor.

[0006] Preferably, the flow regulating mechanism is configured as a peristaltic pump, and the fluid path in the flow regulating mechanism is in communication with the medical catheter.

[0007] Preferably, the flow regulating mechanism comprises at least two pump heads, at least two branch hoses and a driving device, the output portion of the driving device is connected to the pump head through a transmission assembly, the pump heads are arranged alternately, each branch hose is installed on its corresponding pump head, one end opening of the branch hoses is connected to the liquid inlet end of the flow regulating mechanism, and the other end opening of the branch hoses is connected to the liquid outlet end of the flow regulating mechanism.

[0008] Preferably, the detection parts of the first ultrasonic detection device and the second ultrasonic detection device are both provided with temperature measuring devices, the detection parts of the temperature measuring devices are in contact with the medical catheter in the measuring space, and a gap is provided in the measuring space for the medical catheter to expand.

[0009] Preferably, it further includes a pulsation damping mechanism for eliminating the liquid pulsation in the medical catheter. The adjustment part of the pulsation damping mechanism is arranged between the flow rate adjustment mechanism and the second ultrasonic detection device, and a pulsation suppression station for loading the medical catheter is provided in the pulsation damping mechanism.

[0010] To solve the above technical problems, the second aspect of the present invention adopts the following technical solution: A constant pressure flow rate testing method for a medical catheter, applying a constant pressure flow rate testing device for a medical catheter as described above, includes the following steps:

[0011] S1: Initialize the constant pressure flow rate testing device, set at least two detection points on the medical catheter, and perform flow rate adjustment work on the medical catheter between adjacent detection points;

[0012] S2: Obtain preset working parameters, input liquid into the medical catheter according to the preset pressure value, and obtain the first flow rate information by ultrasonic flow detection at the detection point close to the liquid path head end among adjacent detection points;

[0013] S3: Calculate the real-time flow rate information through the first flow rate information and the cross-sectional area of the medical catheter at zero pressure value;

[0014] S4: Perform flow rate adjustment work on the medical catheter between adjacent detection points through the calculated real-time flow rate information;

[0015] S5: Obtain the second flow rate information by ultrasonic flow detection at the detection point close to the liquid path tail end among adjacent detection points;

[0016] S6: Calculate the cross-sectional area of the medical catheter at this detection point through the second flow rate information and the real-time flow rate information, call the preset relationship table between the pressure and the cross-sectional area in the medical catheter, obtain the real-time pressure value at the liquid path tail end by looking up the table, and adjust the liquid delivery work by comparing the real-time pressure value and the preset pressure value until the real-time pressure value at the liquid path tail end is adjusted to the preset pressure value.

[0017] When the present invention works, it can realize a series of functions such as liquid flow rate testing, flow rate adjustment, and pressure detection and adjustment in the medical catheter, with high intelligence and automation, and can realize the correction of the flow rate, effectively improve the flow rate testing accuracy, facilitate the precise control of the flow rate and pressure of liquid delivery, be applicable to work scenarios with high refinement, have a high safety factor, and can be used for the medical catheter delivery work of a variety of different liquids, with good versatility.

[0018] Preferably, in the step S2, the following steps are further included: obtaining the real-time temperature of the liquid in the medical catheter, obtaining the propagation speed of ultrasonic waves in the liquid at the current temperature by looking up a table, and correcting the first flow rate information by using this propagation speed. The calculation of the first flow rate information adopts the following formula:

[0019]

[0020] Where: v is the flow rate at the current detection point, f d is the frequency shift at the current detection point, T is the liquid temperature at the current detection point, c(T) is the propagation speed of ultrasonic waves obtained at the current detection point, f0 is the ultrasonic reflection frequency, and the symbol θ is the angle between the ultrasonic beam and the liquid flow direction at the current detection point.

[0021] Preferably, in the step S2, the following steps are further included: sequentially setting a plurality of detection points at a position on the medical catheter close to the head end of the liquid path, calculating the average flow rate after obtaining the flow rate information of each detection point to obtain the first flow rate information. The calculation of the flow rate information at each detection point adopts the following formula:

[0022]

[0023] Where: v i is the flow rate at the i-th detection point, f d，i is the frequency shift at the i-th detection point, is the liquid temperature at the i-th detection point, T i is the propagation speed of ultrasonic waves obtained at the i-th detection point, c(T i ) is the ultrasonic reflection frequency, θ i is the angle between the ultrasonic beam and the liquid flow direction at the i-th detection point.

[0024] Preferably, in the step S2, the following steps are further included: performing weight distribution on the flow rate information of a plurality of detection points, and calculating the first flow rate information by using the weighted average method. The weighted average calculation of the first flow rate information adopts the following formula:

[0025]

[0026] Where: is the first flow rate information after weighted average calculation, w i is the weight of the i-th detection point.

[0027] Preferably, in the step S6, when calling the preset relationship table between the pressure and cross-sectional area in the medical catheter and obtaining the real-time pressure value at the end of the liquid path by looking up the table, the following steps are adopted: obtaining the real-time temperature of the liquid in the medical catheter, obtaining the relationship table between the pressure and cross-sectional area in the medical catheter corresponding to this real-time temperature, and obtaining the real-time pressure value at the end of the liquid path by looking up the table.

[0028] The beneficial technical effects of the present invention include:

[0029] 1. The present invention can achieve ultrasonic flow velocity testing at multiple detection points, as well as a series of functions such as pressure detection and regulation inside a medical catheter. It has a high degree of automation, is suitable for long-distance liquid transportation work, can effectively reduce the pressure difference caused by various factors in a long liquid path, can achieve the constant pressure transportation function of a medical catheter, and can also avoid direct contact with the liquid inside the medical catheter, thus preventing liquid contamination and greatly improving the safety factor.

[0030] 2. The present invention can achieve a series of functions such as liquid flow velocity testing, flow rate regulation, and pressure detection and regulation inside a medical catheter. It has a high degree of intelligence and automation, can correct the flow velocity, effectively improve the accuracy of flow velocity testing, facilitate precise control of the flow velocity and pressure of liquid transportation, is suitable for work scenarios with a high degree of refinement, has a high safety factor, and can be used for the transportation of medical catheters with various different liquids, showing good versatility.

[0031] Other features and advantages of the present invention will be disclosed in detail in the following specific embodiments and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be further described below with reference to the drawings:

[0033] Figure 1 It is a schematic structural diagram of a constant pressure and flow velocity testing device for a medical catheter;

[0034] Figure 2 It is a working flowchart of a constant pressure and flow velocity testing method for a medical catheter. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The technical solutions of the embodiments of the present invention will be explained and described below with reference to the drawings of the embodiments of the present invention. However, the following embodiments are only the preferred embodiments of the present invention and not all of them. Based on the embodiments in the embodiments, other embodiments obtained by those skilled in the art without creative efforts all fall within the protection scope of the present invention.

[0036] In the following description, terms such as "inside", "outside", "above", "below", "left", "right", etc., indicating directions or positional relationships are only for the convenience of describing the embodiments and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0037] Embodiment 1:

[0038] Please refer to Figure 1This embodiment discloses a constant pressure flow rate testing device for a medical catheter, including a main control module 1, a first ultrasonic detection device 2, a second ultrasonic detection device 3 and a flow regulating mechanism 4, which will be described in detail below with reference to the accompanying drawings.

[0039] See also Figure 1 and Figure 2 In this embodiment, the first ultrasonic detection device 2, the second ultrasonic detection device 3 and the flow regulating mechanism 4 are all data-connected to the main control module 1. The detection position of the first ultrasonic detection device 2, the flow regulating mechanism 4 and the detection position of the second ultrasonic detection device 3 are arranged in sequence. The first ultrasonic detection device 2 and the second ultrasonic detection device 3 are both provided with a measuring space for the medical catheter to be loaded. After obtaining the liquid flow rate in the medical catheter through ultrasonic detection, the first ultrasonic detection device 2 outputs the first flow rate information to the main control module 1. The flow regulating mechanism 4 works to output a matching flow after calculating the flow control information output by the first flow rate information through the main control module 1. After obtaining the liquid flow rate in the medical catheter through ultrasonic detection, the second ultrasonic detection device 3 outputs the second flow rate information to the main control module 1. The main control module 1 obtains the pressure value difference by calculating the first flow rate information and the second flow rate information and outputs a control signal to the corresponding liquid delivery device to adjust the pressure value in the medical catheter to a preset pressure value.

[0040] When the present embodiment is working, it can realize a series of functions such as ultrasonic flow velocity testing at multiple detection points, as well as pressure detection and regulation in the medical catheter, etc. It has a high degree of automation and is suitable for long-distance liquid transportation. It can effectively reduce the pressure difference caused by various factors in a long liquid path, and can realize the constant pressure transportation function of the medical catheter. At the same time, it can avoid direct contact with the liquid in the medical catheter, avoid the contamination of the liquid, and greatly improve the safety factor.

[0041] In specific implementation, the flow regulating mechanism 4 is configured as a peristaltic pump, and the liquid path in the flow regulating mechanism 4 is connected to the medical catheter. As a further improvement of this embodiment, the flow regulating mechanism 4 includes at least two pump heads, at least two branch hoses and a driving device. The output part of the driving device is connected to the pump head through a transmission assembly. The pump heads are arranged alternately, and each branch hose is installed on its corresponding pump head. One end opening of the branch hoses is connected to the liquid inlet end of the flow regulating mechanism 4, and the other end opening of the branch hoses is connected to the liquid outlet end of the flow regulating mechanism 4. It can effectively reduce the influence of pulsation on the test accuracy, and is suitable for liquid transportation of various viscosities, with a large workload range and a wide range of applications.

[0042] In this embodiment, temperature measuring devices are provided at the detection parts of the first ultrasonic detection device 2 and the second ultrasonic detection device 3. The detection parts of the temperature measuring devices are in contact with the medical catheter in the measurement space. A gap for the expansion of the medical catheter is provided in the measurement space, and the flow rate test result can be corrected in real time according to the temperature of the liquid in the medical catheter, improving the test accuracy.

[0043] Specifically, it further includes a pulsation damping mechanism 5 for eliminating the pulsation of the liquid in the medical catheter. The adjustment part of the pulsation damping mechanism 5 is arranged between the flow rate adjustment mechanism 4 and the second ultrasonic detection device 3. A pulsation suppression station for loading the medical catheter is provided in the pulsation damping mechanism 5.

[0044] Embodiment Two:

[0045] Please refer to Figure 2 , this embodiment provides a constant pressure flow rate test method for a medical catheter, applying a constant pressure flow rate test device for a medical catheter as described in the above embodiment, including the following steps:

[0046] S1: Initialize the constant pressure flow rate test device, set at least two detection points on the medical catheter, and perform flow rate adjustment work on the medical catheter between adjacent detection points;

[0047] S2: Obtain the preset working parameters, input liquid into the medical catheter according to the preset pressure value, and obtain the first flow rate information by ultrasonic flow detection at the detection point close to the liquid path head end among adjacent detection points;

[0048] S3: Calculate the real-time flow rate information through the first flow rate information and the cross-sectional area of the medical catheter at zero pressure value;

[0049] S4: Perform flow rate adjustment work on the medical catheter between adjacent detection points through the calculated real-time flow rate information;

[0050] S5: Obtain the second flow rate information by ultrasonic flow detection at the detection point close to the liquid path tail end among adjacent detection points;

[0051] S6: Calculate the cross-sectional area of the medical catheter at this detection point through the second flow rate information and the real-time flow rate information, call the preset relationship table between the pressure and the cross-sectional area in the medical catheter, obtain the real-time pressure value at the liquid path tail end by looking up the table, and adjust the liquid delivery work by comparing the real-time pressure value and the preset pressure value until the real-time pressure value at the liquid path tail end is adjusted to the preset pressure value.

[0052] When this embodiment works, it can realize a series of functions such as the measurement of the liquid flow rate in the medical catheter, flow rate adjustment, and the detection and adjustment of the pressure in the medical catheter. It has a high degree of intelligence and automation, and can realize the correction of the flow rate, which can effectively improve the accuracy of the flow rate measurement, facilitate the precise control of the flow rate and pressure of the liquid delivery, is applicable to the working scenarios with high refinement degree, has a high safety factor, and can be used for the medical catheter delivery work of a variety of different liquids, with good versatility.

[0053] In this embodiment, in step S2, the following steps are further included: obtaining the real-time temperature of the liquid in the medical catheter, obtaining the propagation speed of ultrasonic waves in the liquid at the current temperature by looking up a table, and correcting the first flow rate information with this propagation speed. The calculation of the first flow rate information uses the following formula:

[0054]

[0055] Where: v is the flow rate at the current detection point, f d is the frequency shift at the current detection point, T is the liquid temperature at the current detection point, c(T) is the ultrasonic wave propagation speed obtained at the current detection point, f0 is the ultrasonic wave reflection frequency, and the symbol θ is the angle between the ultrasonic beam and the liquid flow direction at the current detection point.

[0056] As a further improvement of this embodiment, when the medical catheter is relatively long, there are generally multiple pipe diameter change points. Therefore, it is necessary to comprehensively calculate the flow rate information at multiple detection points to obtain the average flow rate information to reduce the flow rate measurement error. In step S2, the following steps are further included: sequentially setting several detection points at the position close to the liquid path head end on the medical catheter, calculating the average flow rate after obtaining the flow rate information of each detection point, and obtaining the first flow rate information. The calculation of the flow rate information at each detection point uses the following formula:

[0057]

[0058] Where: v i is the flow rate at the i-th detection point, f d，i is the frequency shift at the i-th detection point, is the liquid temperature at the i-th detection point, T i is the ultrasonic wave propagation speed obtained at the i-th detection point, c(T i ) is the ultrasonic wave reflection frequency, θ i is the angle between the ultrasonic beam and the liquid flow direction at the i-th detection point.

[0059] Preferably, in order to further improve the accuracy of the flow rate measurement, in step S2, the following steps are further included: performing weight assignment on the flow rate information of several detection points, and calculating the first flow rate information by using the weighted average method. The weighted average calculation of the first flow rate information uses the following formula:

[0060]

[0061] Wherein: is the first flow velocity information after weighted average calculation, w i is the weight of the i-th detection point.

[0062] In specific implementation, in step S6, when calling the pre-set relationship table of the pressure and cross-sectional area in the medical catheter and obtaining the real-time pressure value at the end of the liquid path by looking up the table, the following steps are adopted to obtain the real-time temperature of the liquid in the medical catheter, obtain the relationship table of the pressure and cross-sectional area in the medical catheter corresponding to this real-time temperature, and obtain the real-time pressure value at the end of the liquid path by looking up the table.

[0063] The beneficial technical effects of this embodiment include: The present invention can realize a series of functions such as ultrasonic flow velocity testing at multiple detection points, pressure detection and adjustment in the medical catheter, etc. It has a high degree of automation, is suitable for long-distance liquid transportation work, can effectively reduce the pressure difference caused by various factors in a long liquid path, can realize the constant pressure transportation function of the medical catheter, and at the same time can avoid direct contact with the liquid in the medical catheter, thus avoiding the situation of contaminating the liquid and greatly improving the safety factor.

[0064] As described above, only the specific implementation manners of the present invention are provided, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the content described in the drawings and the above specific implementation manners. Any modification that does not deviate from the functional and structural principles of the present invention will be included in the scope of the claims.

Claims

1. A constant pressure flow rate testing device for a medical catheter, characterized in that: The invention comprises a main control module (1), a first ultrasonic detection device (2), a second ultrasonic detection device (3) and a flow regulating mechanism (4); the first ultrasonic detection device (2), the second ultrasonic detection device (3) and the flow regulating mechanism (4) are all data-connected to the main control module (1); the detection part of the first ultrasonic detection device (2), the flow regulating mechanism (4) and the detection part of the second ultrasonic detection device (3) are arranged in sequence; the first ultrasonic detection device (2) and the second ultrasonic detection device (3) are both provided with a measuring space for inserting a medical catheter; the first ultrasonic detection device (2) is After obtaining the liquid flow rate in the medical catheter through ultrasonic detection, first flow rate information is output to the main control module (1); the flow regulating mechanism (4) works to output a matching flow rate after calculating the flow control information output by the first flow rate information through the main control module (1); the second ultrasonic detection device (3) outputs second flow rate information to the main control module (1) after obtaining the liquid flow rate in the medical catheter through ultrasonic detection; the main control module (1) obtains a pressure value difference by calculating the first flow rate information and the second flow rate information and outputs a control signal to a corresponding liquid delivery device to adjust the pressure value in the medical catheter to a preset pressure value.

2. The constant pressure flow rate testing device for a medical catheter according to claim 1, wherein: The flow regulating mechanism (4) is configured as a peristaltic pump, and the liquid path within the flow regulating mechanism (4) is in communication with the medical catheter.

3. The constant pressure flow rate testing device for a medical catheter according to claim 1, wherein: The flow regulating mechanism (4) comprises at least two pump heads, at least two branch hoses and a driving device, wherein the output portion of the driving device is connected to the pump head through a transmission assembly, the pump heads are arranged alternately, each branch hose is installed on its corresponding pump head, one end opening of the branch hoses is connected to the liquid inlet end of the flow regulating mechanism, and the other end opening of the branch hoses is connected to the liquid outlet end of the flow regulating mechanism.

4. The constant pressure flow rate testing device for a medical catheter according to claim 1, characterized in that: The detection part of the first ultrasonic detection device (2) and the detection part of the second ultrasonic detection device (3) are both provided with temperature measuring devices, the detection parts of the temperature measuring devices are in contact with the medical catheter in the measurement space, and a gap is provided in the measurement space for the medical catheter to expand.

5. The constant pressure flow rate testing device for a medical catheter according to claim 1, characterized in that: It also includes a pulsation damping mechanism (5) for eliminating the pulsation of the liquid in the medical catheter. The regulating part of the pulsation damping mechanism (5) is arranged between the flow regulating mechanism (4) and the second ultrasonic detection device (3). The pulsation damping mechanism (5) is provided with a pulsation suppression station for the medical catheter to be installed.

6. A constant-pressure flow rate testing method for a medical catheter, which applies a constant-pressure flow rate testing device for a medical catheter as described in any one of claims 1 to 5, characterized in that, The following steps are involved: S1: Initialize the constant pressure flow rate test device, set at least two detection points on the medical catheter, and adjust the flow rate of the medical catheter between adjacent detection points; S2: obtaining preset working parameters, inputting liquid into the medical catheter according to a preset pressure value, and obtaining first flow rate information by ultrasonic flow detection at a detection point close to the head end of the liquid path among adjacent detection points; S3: obtaining real-time flow information by calculating the first flow rate information and the cross-sectional area of ​​the medical catheter at a zero pressure value; S4: Regulating the flow of the medical catheter between adjacent detection points based on the calculated real-time flow information; S5: Obtain the second flow velocity information by ultrasonic flow detection at the detection point close to the end of the liquid path among adjacent detection points; S6: Calculate the cross-sectional area of the medical catheter at this detection point based on the second flow velocity information and the real-time flow rate information, call the pre-set relationship table of the pressure and cross-sectional area inside the medical catheter, obtain the real-time pressure value at the end of the liquid path by looking up the table, and adjust the liquid delivery operation by comparing the real-time pressure value with the pre-set pressure value until the real-time pressure value at the end of the liquid path is adjusted to the pre-set pressure value.

7. A constant pressure flow rate testing method for a medical catheter according to claim 6, characterized in that: In the step S2, the following steps are further included: obtain the real-time temperature of the liquid inside the medical catheter, obtain the propagation speed of ultrasonic waves in the liquid at the current temperature by looking up the table, and correct the first flow velocity information with this propagation speed. The calculation of the first flow velocity information adopts the following formula: Where: v is the flow velocity of the current detection point, f d is the frequency shift of the current detection point, T is the liquid temperature at the current detection point, c(T) is the ultrasonic wave propagation speed obtained at the current detection point, f0 is the ultrasonic wave reflection frequency, and the symbol θ is the angle between the ultrasonic beam and the liquid flow direction at the current detection point.

8. A constant pressure flow rate testing method for a medical catheter according to claim 6, characterized in that: In the step S2, the following steps are further included: sequentially set a number of detection points at a position close to the head end of the liquid path on the medical catheter, calculate the average flow velocity after obtaining the flow velocity information of each detection point, and obtain the first flow velocity information. The calculation of the flow velocity information at each detection point adopts the following formula: Where: v i is the flow velocity at the i-th detection point, f d，i is the frequency shift at the i-th detection point, is the liquid temperature at the i-th detection point, T i is the ultrasonic wave propagation velocity obtained at the i-th detection point, c(T i ) is the ultrasonic wave reflection frequency, θ i is the angle between the ultrasonic beam and the liquid flow direction at the i-th detection point.

9. A constant pressure flow rate testing method for a medical catheter according to claim 8, characterized in that: In the step S2, the following steps are further included: perform weight assignment on the flow velocity information of a number of detection points, and calculate the first flow velocity information by means of weighted average. The weighted average calculation of the first flow velocity information adopts the following formula: Wherein: is the first flow rate information after weighted average calculation, w i is the weight of the i-th detection point.

10. A constant pressure flow rate testing method for a medical catheter according to claim 6, characterized in that: In the step S6, when calling the pre-set relationship table of the pressure and cross-sectional area inside the medical catheter and obtaining the real-time pressure value at the end of the liquid path by looking up the table, the following steps are adopted: obtain the real-time temperature of the liquid inside the medical catheter, obtain the relationship table of the pressure and cross-sectional area inside the medical catheter corresponding to this real-time temperature, and obtain the real-time pressure value at the end of the liquid path by looking up the table.

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