Fluid pressure detection sensor and flow sensor assembly for vapor ablation

Abstract

The utility model relates to fluid detection technical field provides a kind of fluid pressure detection sensor and flow sensor assembly for steam ablation, fluid pressure detection sensor includes shell, flexible expansion pipe and pressure film, the flexible expansion pipe is worn in the shell, the both ends of the flexible expansion pipe protrude the shell;The pressure film is located in the shell, and is covered in the flexible expansion pipe outside, and gap is formed between the pressure film and the flexible expansion pipe, and the gap is used to fill buffer medium.The utility model forms the structure of buffer gap by setting flexible expansion pipe and pressure film in shell, effectively isolates the direct heat impact of high-temperature steam to pressure film, simultaneously compatible liquid and gas medium's pressure detection, with the advantages of high temperature resistance, stable structure and high measurement accuracy.

Description

Technical Field

[0001] This utility model relates to the field of fluid detection technology, and in particular to fluid pressure detection sensors and flow sensor components for steam ablation. Background Technology

[0002] In the medical industry, the use of latent heat released by the phase change of steam to kill diseased tissues and cells is becoming a research hotspot, and corresponding steam ablation equipment is receiving widespread attention. These devices require the integration of multiple sensors to ensure operational accuracy and stability, with pressure sensors being a core component. These sensors monitor the pressure parameters of fluids such as sterile water, saline solution, and steam. Based on feedback data from the pressure sensors, the equipment can determine its operating status in real time, including whether there are leaks, air leaks, or pipe blockages. It can also assess whether the temperature is too high or whether the equipment's power exceeds safe limits through steam pressure monitoring.

[0003] However, existing pressure sensors face significant technical bottlenecks in steam ablation applications: the upper limit of the operating temperature of conventional sensors is usually no more than 80°C, while the temperature of medical steam is generally higher than 100°C, which leads to sensor performance failure or a significant reduction in lifespan; most pressure sensors on the market have single functions, liquid pressure sensors and gas pressure sensors are incompatible with each other, and sensors that can measure two media at the same time either have insufficient measurement accuracy or are too expensive. Utility Model Content

[0004] This invention aims to solve at least one of the technical problems existing in related technologies. To this end, this invention proposes a fluid pressure detection sensor that has the advantages of high temperature resistance, structural stability, and compatibility with both liquid and gas pressure detection.

[0005] This invention also proposes a flow sensor assembly for steam ablation.

[0006] The fluid pressure detection sensor according to a first aspect of the present invention includes: shell; A flexible expansion tube, wherein the flexible expansion tube passes through the outer shell and both ends of the flexible expansion tube extend out of the outer shell; A pressure diaphragm is disposed inside the outer shell and covers the flexible expansion tube, and a gap is formed between the pressure diaphragm and the flexible expansion tube, the gap being used to fill a buffer medium.

[0007] According to the embodiment of the present invention, the fluid pressure detection sensor effectively isolates the pressure membrane from direct thermal shock by high-temperature steam by setting a flexible expansion tube and a pressure diaphragm to form a buffer gap inside the housing. At the same time, it is compatible with pressure detection of liquid and gas media and has the advantages of high temperature resistance, stable structure and high measurement accuracy.

[0008] According to one embodiment of the present invention, the buffer medium is a gas.

[0009] According to one embodiment of the present invention, the pressure diaphragm is a resistive pressure diaphragm, which is used to connect to an external detection circuit.

[0010] According to one embodiment of the present invention, the pressure diaphragm has a range of less than or equal to 1 MPa.

[0011] According to one embodiment of the present invention, the gas is nitrogen or carbon dioxide.

[0012] According to one embodiment of the present invention, at least one end of the flexible expansion tube is provided with a connector, which is used to connect to the pipeline under test.

[0013] According to one embodiment of the present invention, both ends of the flexible expansion tube are provided with the connectors, and one of the two connectors is selectively connected to the pipeline under test.

[0014] The flow sensor assembly for steam ablation according to a second aspect embodiment of the present invention includes: A fluid tube, which is used to connect to the pipeline being tested; At least two of the above-mentioned fluid pressure detection sensors are arranged at intervals along the fluid tube, wherein one end of the flexible expansion tube is connected to the fluid tube and the other end is blocked.

[0015] According to one embodiment of the present invention, the fluid tube has a narrow section, and one of the fluid pressure detection sensors is located at the narrow section.

[0016] According to one embodiment of the present invention, the fluid tube is a rigid fluid tube.

[0017] The flow sensor assembly for steam ablation according to the present invention includes the above-mentioned fluid pressure detection sensor, and therefore has all the technical effects of the above-mentioned fluid pressure detection sensor, which will not be repeated here.

[0018] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of the fluid pressure detection sensor provided in this embodiment of the utility model.

[0021] Figure 2 This is a cross-sectional schematic diagram of the fluid pressure detection sensor provided in this embodiment of the present invention.

[0022] Figure 3 This is a schematic diagram of the structure of a flow sensor assembly for steam ablation provided in an embodiment of this utility model.

[0023] Figure 4 This is a schematic diagram of the pressure detection circuit of the fluid pressure detection sensor provided in this embodiment of the utility model.

[0024] Figure label: 1. Fluid pressure sensor; 11. Housing; 12. Flexible expansion tube; 13. Pressure diaphragm; 14. Gap; 15. Connector; 2. Fluid tube. Detailed Implementation

[0025] The embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of this utility model.

[0026] In the description of the embodiments of this utility model, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this utility model. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of the embodiments of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this utility model based on the specific circumstances.

[0028] In this embodiment of the utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0029] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0030] In existing technologies, pressure sensors used in medical devices generally face technical bottlenecks such as poor adaptability to high-temperature conditions, limited media compatibility, and excessive size. Conventional sensors are prone to material deformation or signal drift in environments exceeding 80°C, failing to meet the detection requirements above 100°C in vapor ablation scenarios. Furthermore, traditional pressure sensors typically employ a single detection structure, requiring separate sensors for liquid and gas pressure detection, increasing system complexity and cost. In interventional medical devices, the size of existing sensors is insufficient to meet the application requirements of the confined spaces inside the human body, limiting their widespread application in minimally invasive surgery.

[0031] Therefore, please refer to the following: Figure 1 and Figure 2This application proposes a fluid pressure detection sensor 1 comprising a housing 11, a flexible expansion tube 12, and a pressure diaphragm 13. The flexible expansion tube 12 penetrates the housing 11 and extends outward at both ends, and the pressure diaphragm 13 covers the outside of the flexible expansion tube 12 to form a gap 14 filled with a buffer medium.

[0032] The outer shell 11 refers to the rigid protective structure that encloses the internal components. It can be made of stainless steel or high-temperature resistant engineering plastics and serves to define the overall size of the sensor and provide mechanical support. The flexible expansion tube 12 is an elastic conduit that deforms with pressure changes. It can be made of silicone rubber or fluororubber and is used to directly contact the measured fluid and transmit pressure. The pressure diaphragm 13 is the detection element that converts mechanical deformation into an electrical signal; pressure detection is achieved by changing resistance due to deformation. The gap 14 is the cavity structure between the pressure diaphragm 13 and the flexible expansion tube 12, used to accommodate a buffer medium to isolate thermal expansion stress.

[0033] Specifically, the outer shell 11 acts as a rigid frame constraining the internal component layout, compressing the overall size of the sensor to a size suitable for medical interventional devices. The flexible expansion tube 12 has both ends exposed outside the outer shell 11, allowing direct connection to liquid or gas lines. Its elastic properties ensure uniform liquid pressure transmission and effectively buffer gas pressure fluctuations. The pressure diaphragm 13 covers the flexible expansion tube 12, forming a sealed detection area. When the pressure of the measured medium changes, the flexible expansion tube 12 expands radially, compressing the pressure diaphragm 13 and causing deformation, outputting a pressure signal through changes in resistance. The buffer medium filling the gap 14 absorbs the thermal expansion difference between the flexible expansion tube 12 and the pressure diaphragm 13 under high-temperature conditions, preventing membrane tearing or signal distortion caused by differences in material expansion coefficients.

[0034] Through the above technical solution, since the steam flows within the flexible expansion tube 12 and does not directly contact the pressure membrane 13, this application can operate stably in steam environments above 100°C, avoiding detection errors caused by differences in thermal expansion. The synergistic effect of the flexible expansion tube 12 and the pressure membrane 13 allows the sensor to be used for both liquid and gas pressure detection without the need to replace the detection element. The integrated packaging structure reduces the sensor size to a size suitable for implantation in medical devices, meeting the needs of minimally invasive surgical scenarios. The pressure fluctuation absorption characteristics of the buffer medium improve the sensor's measurement accuracy under pulsed pressure environments, expanding the operating condition adaptability range of medical devices.

[0035] This application further proposes that the buffer medium be a gas.

[0036] The buffer medium refers to the substance filling the gap 14 between the pressure membrane 13 and the flexible expansion tube 12. Specifically, nitrogen, carbon dioxide or other inert gases can be used. These gases have a low rate of volume change at high temperatures, which can reduce the interference of thermal expansion on pressure transmission.

[0037] Specifically, under high-temperature conditions, the volume change of gas upon heating is smaller, resulting in a lower coefficient of thermal expansion compared to liquid media. When the sensor is applied to a steam ablation device, high-temperature steam may cause the medium within gap 14 to expand. However, the gaseous medium, through its physical properties, suppresses the expansion amplitude, thereby maintaining the stability of gap 14 between pressure diaphragm 13 and flexible expansion tube 12. Thus, pressure diaphragm 13 can accurately sense the deformation of flexible expansion tube 12 caused by fluid pressure changes, avoiding pressure signal distortion due to excessive medium expansion.

[0038] This application further proposes that the pressure diaphragm 13 is a resistive pressure diaphragm 13, which is used to connect to an external detection circuit.

[0039] The resistive pressure membrane 13 refers to a thin-film element made of pressure-sensitive material, whose resistance changes linearly or non-linearly with the applied pressure. Specifically, it can be implemented using a polyimide substrate doped with carbon nanotubes, forming a thin-film structure with specific resistance characteristics through a printing process. This structure maintains chemical stability at high temperatures, avoiding measurement errors caused by thermal expansion. The external detection circuit is a circuit module used to acquire and process the electrical signals from the resistive pressure membrane 13. Specifically, it can be implemented using a Wheatstone bridge circuit, converting the resistance change into a voltage signal through a differential amplifier circuit, and combining this with a temperature compensation algorithm to eliminate the influence of ambient temperature on the resistance value.

[0040] Specifically, when fluid pressure acts on the flexible expansion tube 12, the pressure is transmitted to the resistive pressure diaphragm 13 through the buffer medium, causing the diaphragm to deform and change the contact area of ​​the internal conductive network, resulting in a change in resistance. The external detection circuit acquires the change in resistance in real time, and after signal conditioning and analog-to-digital conversion, outputs a digital signal corresponding to the pressure. The high-temperature resistance of the substrate of the resistive pressure diaphragm 13 ensures stable resistance characteristics in steam melting scenarios. The external detection circuit eliminates thermal noise interference through a temperature compensation module, ensuring pressure detection accuracy.

[0041] For example, a schematic diagram of a pressure detection circuit is shown below. Figure 4 As shown: In the diagram, a variable resistor X1 represents the fluid pressure sensor 1, whose resistance changes with pressure. X1, along with three other fixed resistors R1 to R3, forms a Wheatstone bridge. After the bridge is connected to a power source, the resistance value can be accurately measured by measuring the voltage at the midpoint between the two bridge arms. Using this circuit, the resistance measurement error of the pressure sensor (X1) can be reduced.

[0042] When the midpoint voltage of the bridge arm is connected to a linear amplifier circuit, conventional operational amplifier circuits are more accurate than amplifier circuits built with discrete components. The topology can employ in-phase proportional amplification, inverting proportional amplification, differential amplification, etc., combined with resistors and energy storage components—such as inductors and capacitors—for synchronous filtering, such as Butterworth circuits and Chebyshev circuits, to reduce interference and further improve detection accuracy.

[0043] A digital-to-analog converter (ADC) circuit digitizes the amplified analog voltage signal so that it can be processed by the subsequent MCU (Microcontroller Unit), since MCUs can only recognize digital signals. This ADC circuit can be either a standalone ADC circuit or utilize the ADC circuit integrated within the MCU chip.

[0044] The MCU can reverse the voltage-resistance-pressure relationship formula to calculate the pressure value. Furthermore, to improve accuracy, Kalman filtering can be used to further reduce errors.

[0045] This application further proposes that the range of the pressure diaphragm 13 is less than or equal to 1 MPa.

[0046] The measuring range of the pressure membrane 13 refers to the maximum pressure range that the pressure membrane 13 can measure. Specifically, it can be achieved by using a polymer composite material with a specific elastic modulus, which can maintain stable deformation characteristics under high pressure. The upper limit of the measuring range is set based on the matching relationship between the thermal expansion coefficient of the pressure membrane 13 material and the temperature-pressure coupling conditions in the vapor melting scenario, thereby preventing plastic deformation of the material by limiting the maximum working pressure.

[0047] Specifically, in high-pressure steam ablation scenarios, when the pressure membrane 13 operates within a 1 MPa range, the stress distribution of its internal lattice structure remains within a linear response range, resulting in a stable correlation between the rate of change of resistance and the external pressure. When steam pressure acts on the pressure membrane 13, the membrane undergoes uniform deformation, and this deformation is transmitted to the external detection circuit through changes in resistance, forming a precise pressure signal. The thermal stability of the pressure membrane 13 is ensured through both material selection and range limitation, avoiding measurement errors caused by material softening under high-temperature conditions.

[0048] This application further proposes that the buffer medium use nitrogen, carbon dioxide, or an inert gas as the filling gas.

[0049] Specifically, nitrogen gas prevents oxidation reactions from damaging the conductivity of the resistive pressure membrane 13 by isolating it from oxygen. Carbon dioxide maintains its gaseous properties within the temperature range of 100-150℃, and its expansion coefficient has a linear relationship with the deformation amplitude of the flexible expansion tube 12. Inert gases maintain their molecular structural integrity even in a vapor melting environment exceeding 200℃, preventing impurity particles generated by gas decomposition from clogging the channels of the gap 14.

[0050] This application further proposes to provide a connector 15 at at least one end of the flexible expansion tube 12, the connector 15 being used to connect to the pipeline under test.

[0051] The flexible expansion tube 12 is a tubular structure made of flexible material, specifically silicone or fluororubber. The flexible expansion tube 12 deforms with changes in fluid pressure and transmits pressure to the pressure membrane 13. The connector 15 is an interface component used to connect the pipeline, specifically a quick-connect connector 15 or a threaded connector 15. The connector 15 is integrally formed or sealed and welded to the end of the flexible expansion tube 12 to ensure the airtightness of fluid transmission.

[0052] Specifically, one end of the flexible expansion tube 12 is directly connected to the pipeline under test via a connector 15, eliminating the need for additional fixing structures. This simplifies the installation process and reduces the overall size of the sensor. The standardized interface design of the connector 15 can adapt to pipelines of different diameters or connection methods. When only one end of the flexible expansion tube 12 is equipped with the connector 15, the other end can be sealed to form a closed cavity, and pressure detection is achieved by measuring the fluid pressure flowing into the flexible expansion tube 12. In steam ablation equipment, this design allows the sensor to be directly connected to narrow interventional catheters or rigid fluid tubes 2, avoiding operational limitations caused by excessive size.

[0053] This application further proposes that both ends of the flexible expansion tube 12 are provided with connectors 15, and one of the two connectors 15 is selectively connected to the pipeline under test. Here, selective connection means that in the actual installation process, only one connector 15 is selected to be connected to the pipeline under test, while the other connector 15 is in a blocked or idle state.

[0054] Specifically, in scenarios where internal space is limited in medical equipment, the sensor, through its two-end connector structure 15, can select the appropriate connection end according to the pipeline layout direction. When one connector 15 is connected to the pipeline being tested, the other connector 15 is closed, allowing the sensor to be installed without adjusting its own orientation. This design eliminates the bending or elongation structure caused by mismatched installation orientation in traditional single-end connector 15 sensors, thereby reducing the space occupied by the sensor within the equipment.

[0055] like Figure 3 As shown, this application further proposes a flow sensor assembly for steam ablation, including a fluid pipe 2 connected to the pipeline under test, and at least two fluid pressure detection sensors 1 arranged at intervals along the fluid pipe 2, wherein one end of the flexible expansion tube 12 of each sensor is connected to the fluid pipe 2 and the other end is blocked.

[0056] The fluid pipe 2 refers to the transmission channel carrying the high-temperature fluid medium. It can be made of a rigid, high-temperature resistant material, such as stainless steel or titanium alloy. A pressure difference detection node can be formed at its narrowest point. The fluid pressure sensor 1 is a detection unit comprising a flexible expansion tube 12 and a pressure diaphragm 13. Specifically, one end of the flexible expansion tube 12 is sealed and connected to the fluid pipe 2, allowing pressure changes to be transmitted to the pressure diaphragm 13 through a buffer medium. The two spaced sensors refer to an arrangement that maintains a predetermined distance along the axial direction of the fluid pipe 2. This can be achieved by welding or threading the sensors to the outer wall of the fluid pipe 2, and by capturing pressure differences at different locations to calculate flow rate.

[0057] Specifically, when high-temperature steam flows through fluid pipe 2, two sensors detect the fluid pressure at their respective locations. Due to the narrow section of fluid pipe 2, the pressure difference between the two sensors is a function of the flow velocity. The flexible expansion tube 12 transmits the fluid pressure to the pressure membrane 13 through a sealed end, and the buffer medium isolates the pressure membrane 13 from the direct influence of the high-temperature steam. The pressure membrane 13 converts mechanical deformation into a resistance change signal output, and the pressure difference is calculated and flow parameters are derived through external circuitry. This differential pressure detection mechanism avoids direct contact between the sensors and the high-temperature medium, while the dual-point detection structure enables flow measurement within a limited space.

[0058] Through the above technical solutions, this application achieves compatibility between flow detection function and high-temperature operating conditions in steam ablation equipment, solving the measurement failure problem caused by temperature limitations of traditional sensors. The dual-sensor differential pressure layout calculates flow parameters through spatial distribution without increasing the size of individual components, meeting the demand for miniaturized components in medical equipment. The direct connection design between the flexible expansion tube 12 and the fluid tube 2 allows the sensor to simultaneously detect pressure changes in both liquid and gaseous media, avoiding space waste caused by placing multiple types of sensors side-by-side in the equipment.

[0059] This application further proposes a technical solution in which a narrow section is provided in the fluid pipe 2, and a fluid pressure detection sensor 1 is located in the narrow section.

[0060] The narrow section refers to the area where the inner diameter of the fluid pipe 2 is locally reduced. Specifically, this can be achieved through machining or injection molding to form an annular necked section. Its function is to create a throttling effect by changing the cross-sectional area of ​​the flow channel, establishing a correlation between flow velocity and static pressure as the fluid flows through this area. Thus, by changing the pipe diameter, the pressure difference in this section of the fluid can be measured, and the velocity difference can be calculated using Bernoulli's equation, further allowing for the measurement of the flow velocity. The fluid pressure sensor 1 is located at the narrow section, meaning the pressure-sensitive element is directly integrated into the outer wall of the necked section or embedded inside the pipe wall. Its function is to detect pressure changes at a specific location within the narrow section and indirectly calculate flow parameters using fluid dynamics principles, avoiding the volume increase caused by installing additional throttling elements.

[0061] Specifically, by measuring the pressure difference between the narrow section and the upstream standard flow channel, and combining this with Bernoulli's equation, a mathematical relationship between the pressure difference and the flow velocity is established, thereby deriving the flow rate data. Since the pressure sensor is directly integrated into the fluid pipe 2 body structure, no external pressure-conducting pipe or independent throttling device is required, significantly reducing the overall component size. Simultaneously, the flow field characteristics at the narrow section ensure a stable linear correlation between the pressure signal and the flow rate parameters, maintaining measurement accuracy even in high-temperature environments.

[0062] This application further proposes a technical solution where the fluid tube 2 is a rigid fluid tube.

[0063] Rigid fluid tubes refer to tubular structures made of rigid materials, such as stainless steel, titanium alloys, or high-temperature engineering plastics. This feature maintains the stability of the fluid channel geometry by rigidly constraining the deformation of the tube body.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that various combinations, modifications, or equivalent substitutions of the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention and should be covered within the scope of the claims of the present invention.

Claims

1. A fluid pressure detecting sensor characterized by comprising: include: shell; A flexible expansion tube, wherein the flexible expansion tube passes through the outer shell and both ends of the flexible expansion tube extend out of the outer shell; A pressure diaphragm is disposed inside the outer shell and covers the flexible expansion tube, and a gap is formed between the pressure diaphragm and the flexible expansion tube, the gap being used to fill a buffer medium.

2. The fluid pressure detecting sensor according to claim 1, wherein The buffer medium is a gas.

3. The fluid pressure detecting sensor according to claim 1, wherein The pressure diaphragm is a resistive pressure diaphragm, which is used to connect to an external detection circuit.

4. The fluid pressure detecting sensor according to claim 1, wherein The pressure diaphragm has a range of less than or equal to 1 MPa.

5. The fluid pressure detecting sensor according to claim 2, wherein The gas is either nitrogen or carbon dioxide.

6. The fluid pressure detection sensor according to any one of claims 1 to 5, characterized in that, The flexible expansion tube has a connector at at least one end, which is used to connect to the pipeline under test.

7. The fluid pressure detecting sensor according to claim 6, wherein Both ends of the flexible expansion tube are provided with the connectors, and one of the two connectors is connected to the pipeline under test.

8. A flow sensor assembly for use in steam ablation, characterized by, include: A fluid tube, which is used to connect to the pipeline being tested; At least two fluid pressure detection sensors as described in any one of claims 1 to 7, wherein the two fluid pressure detection sensors are spaced apart along the fluid tube, wherein one end of the flexible expansion tube is in communication with the fluid tube and the other end is blocked.

9. The flow sensor assembly for steam ablation of claim 8, wherein, The fluid tube has a narrow section, and one of the fluid pressure detection sensors is located at the narrow section.

10. The flow sensor assembly for steam ablation of claim 9, wherein, The fluid tube is a rigid fluid tube.

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