Working fluid pressure vessel system for cryoablation

Abstract

The present application provides a working fluid pressure vessel system for cryoablation, comprising a first, a second and a third pressure vessel, wherein the first pressure vessel is used to store liquid working fluid and supply liquid working fluid to the cryoablation device during the ablation process; the second pressure vessel is used to store gaseous working fluid and is controllably connected to the first pressure vessel through a fourth pipe, while receiving reflux working fluid from the cryoablation device; the third pressure vessel is arranged in the first pressure vessel for phase-changing the liquid working fluid into gaseous working fluid, the third pressure vessel is controllably connected to the first pressure vessel through a one-way flow device to receive the liquid working fluid, and the third pressure vessel is also controllably connected to the second pressure vessel through a fifth pipe; controlled elements are respectively arranged on the fourth pipe and the fifth pipe, and each controlled element and the one-way flow device are correspondingly turned on and off under expected conditions, so that the pressures of the first pressure vessel, the second pressure vessel and the third pressure vessel are correlated.

Description

Technical Field

[0001] The present application relates to the technical field of medical devices, and in particular to a working fluid pressure vessel system for cryoablation. Background Art

[0002] In the fight against cancer, chemotherapy, radiotherapy, and surgery have become the three main treatments for malignant tumors, with tumor immunotherapy also being actively researched. Minimally invasive tumor treatments are an important complement to surgical interventions, with physical ablation, including microwaves, cryosurgery, lasers, radiofrequency, and high-power focused ultrasound, increasingly being used to induce necrosis of cancerous tissue.

[0003] In the early 20th century, industry and technology advanced rapidly. Advances in industrial technology led to the successful production of refrigerants such as concentrated oxygen, liquid oxygen, concentrated nitrogen, liquid nitrogen, and dry ice. This not only accelerated commercial development but also opened up new avenues for medical refrigeration, advancing the application of cryogenic technology in healthcare. A variety of refrigeration technologies emerged in response to the continuous advancement of cryogenic science. Gas throttling, phase change cooling, vapor pressure absorption refrigeration, and thermoelectric refrigeration are the main refrigeration solutions used in modern medicine.

[0004] In 1998, the American Endocare Cryocare System (Argon-Helium Cryosurgical System), a new ultra-low temperature cryotherapy device, passed US EMC, FDA, and EU CE certifications and entered the medical market, significantly promoting the development of tumor cryotherapy. This technology utilizes the Joule-Thomson principle, using argon and helium as the cooling and heating media, and uses CT or ultrasound to precisely locate lesions. The treatment results are impressive, bringing revolutionary advancements to minimally invasive cryosurgery. However, the operating pressure of the Argon-Helium Cryosurgical System is relatively high (7-20 MPa), posing safety risks during the procedure.

[0005] Especially in low-pressure liquid nitrogen cryoablation systems, liquid nitrogen is directly discharged after vaporization, resulting in high liquid nitrogen consumption. Although there are solutions to recycle nitrogen for rewarming, the reuse rate of nitrogen is still low, resulting in unnecessary waste. Summary of the Invention

[0006] The present application discloses a working fluid pressure container system for cryoablation, which utilizes the container pressure to deliver the working fluid during the ablation process and can also perform corresponding pressure compensation.

[0007] The present application provides a working medium pressure vessel system for cryoablation, comprising a first pressure vessel, a second pressure vessel and a third pressure vessel, wherein

[0008] The first pressure vessel is used to store liquid working fluid and supply the liquid working fluid to the cryoablation device during the ablation process;

[0009] The second pressure vessel is used to store gaseous working fluid and is in controlled communication with the first pressure vessel through a fourth pipeline, while receiving reflux working fluid from the cryoablation device;

[0010] The third pressure vessel is disposed within the first pressure vessel and is used to convert the liquid working medium into a gaseous working medium. The third pressure vessel is in controlled communication with the first pressure vessel via a one-way flow device to receive the liquid working medium. The third pressure vessel is also in controlled communication with the second pressure vessel via a fifth pipeline.

[0011] Controlled elements are respectively arranged on the fourth pipeline and the fifth pipeline. Each controlled element and the one-way flow device are opened and closed accordingly under expected conditions, so that the pressures of the first pressure vessel, the second pressure vessel and the third pressure vessel are correlated.

[0012] Several optional methods are also provided below, but they are not intended to be additional limitations on the above-mentioned overall solution. They are merely further supplements or optimizations. Under the premise that there are no technical or logical contradictions, each optional method can be combined separately for the above-mentioned overall solution, or multiple optional methods can be combined.

[0013] Optionally, the first pressure vessel is equipped with a first pressure sensor for obtaining a first current pressure;

[0014] The controlled elements on the fourth pipeline are a fourth pressure control element and a fourth solenoid valve connected in series in sequence between the second pressure vessel and the first pressure vessel;

[0015] The fourth solenoid valve opens when the first current pressure reaches a first preset pressure value, connecting the second pressure container and the first pressure container, and the fourth pressure control element automatically controls its own output pressure to be lower than its own input pressure.

[0016] Optionally, the second pressure vessel is provided with a second pressure sensor for obtaining a second current pressure;

[0017] The controlled elements on the fifth pipeline are a fifth solenoid valve and a fifth pressure control element which are sequentially connected in series between the third pressure vessel and the second pressure vessel;

[0018] The fifth solenoid valve opens when the second current pressure is lower than the second pressure preset value, connecting the third pressure container and the second pressure container, and the fifth pressure control element automatically controls its own output pressure to be lower than its own input pressure.

[0019] Optionally, the fifth pipeline is provided with a third pressure sensor for monitoring a third pressure vessel to obtain a third current pressure;

[0020] The third pressure vessel is provided with a heating device for heating the liquid working medium in the third pressure vessel to change the phase into gaseous working medium and increase the third current pressure;

[0021] When the third current pressure reaches a third preset pressure value, the heating device stops heating.

[0022] Optionally, the third pressure vessel is provided with a liquid level sensor and a temperature sensor for obtaining a third current liquid level and a third current temperature;

[0023] When the third current liquid level and the third current temperature meet the expected conditions, the heating device stops heating.

[0024] Optionally, the third pressure vessel is provided with an isolation layer for isolating heat conduction.

[0025] Optionally, the second pressure vessel delivers the heated gaseous working medium to the cryoablation device through a sixth pipeline to replace the air and moisture inside the cryoablation device before the cryoablation device operates.

[0026] Optionally, when the third current pressure and the third current liquid level meet expected conditions, the one-way flow device operates to receive the liquid working medium from the first pressure vessel.

[0027] Optionally, the one-way flow device is arranged at the bottom of the third pressure vessel and is below the liquid level in the first pressure vessel.

[0028] Optionally, the first pressure vessel, the second pressure vessel and the third pressure vessel are respectively provided with an exhaust pressure relief pipe, and each exhaust pressure relief pipe is respectively provided with a solenoid valve which opens at a preset pressure to implement pressure relief.

[0029] The working fluid pressure vessel system for cryoablation provided in the present application can maintain the normal and continuous output of working fluid by the first pressure vessel, and can also recycle the working fluid and perform pressure compensation. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the principle of the low-pressure fluid system of this application;

[0031] Figure 2 Schematic diagram of the phase change pressure vessel structure;

[0032] Figures 3 to 8 This is a method flow chart. The connection relationship between each figure can be seen from the corresponding labels at the boundary parts. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0034] It should be noted that when a component is referred to as being "connected" to another component, it may be directly connected to the other component or there may be an intermediate component. When a component is referred to as being "disposed on" another component, it may be directly disposed on the other component or there may be an intermediate component.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0036] In the field of cryoablation, phase-change freezing of liquid cryogens offers higher freezing efficiency than throttling freezing of gaseous cryogens. Liquid nitrogen is a commonly used liquid cryogen, but it is prone to phase change in pipelines, creating "gas blockages" and excessive pressure in the pipelines. This affects the output of liquid nitrogen, resulting in an unstable cryoablation range and difficulty achieving consistent ablation results.

[0037] In existing low-pressure liquid nitrogen cryoablation systems, liquid nitrogen is directly discharged after vaporization, resulting in high liquid nitrogen consumption. Although there are solutions to recycle nitrogen for rewarming, the reuse rate of nitrogen is still low, resulting in unnecessary waste.

[0038] The present application provides a working fluid pressure vessel system for cryoablation, comprising a first pressure vessel (i.e., a liquid working fluid pressure vessel (C1), a second pressure vessel (i.e., a gaseous working fluid pressure vessel (C2) and a third pressure vessel (i.e., a phase change pressure vessel (C3), wherein the first pressure vessel is used to store liquid-phase working fluid and supply liquid-phase working fluid to a cryoablation device (CP) during the ablation process, and the working fluid will be discharged after passing through the cryoablation device; the second pressure vessel is used to store gaseous-phase working fluid and is controlledly connected to the first pressure vessel through a fourth pipeline (i.e., a cryoablation working pressure control element L4-3), and simultaneously receives reflux working fluid from the cryoablation device; the third pressure vessel is arranged in the first pressure vessel for changing the phase of the liquid-phase working fluid into gaseous-phase working fluid; the third pressure vessel is controlledly connected to the first pressure vessel through a one-way flow device to receive the liquid-phase working fluid; the third pressure vessel is also controlledly connected to the second pressure vessel through a fifth pipeline.

[0039] Controlled elements are respectively arranged on the fourth pipeline and the fifth pipeline. Each controlled element and the one-way flow device is opened and closed accordingly under expected conditions, so that the pressures of the first pressure vessel, the second pressure vessel and the third pressure vessel are correlated.

[0040] First, the reflux fluid is the fluid discharged from the cryoablation device, and the second pressure vessel and the cryoablation device can be connected by a pipeline to enable the flow of the reflux fluid. This process is the fluid recovery process. It should be noted that the state change of the fluid during the recovery process is not the key point.

[0041] Secondly, the pressure linkage process between the three pressure vessels involves the working fluid in the third pressure vessel entering the second pressure vessel for pressure compensation, maintaining the second pressure vessel within a preset pressure range; the working fluid in the second pressure vessel entering the first pressure vessel for pressure compensation, maintaining the first pressure vessel within a preset pressure range, and continuously outputting liquid-phase working fluid; the third pressure vessel maintains its own pressure within a preset pressure range by changing the working fluid state. Each of the above pressure vessels corresponds to a preset pressure range. This pressure linkage process utilizes the existing second pressure vessel as a transition to achieve overall automatic pressure cycle control. The pressure vessel system of this embodiment is primarily used to control the pressures within the liquid working fluid pressure vessel (C1), the gaseous working fluid pressure vessel (C2), the phase change pressure vessel (C3), and the liquid delivery pipeline (L1) to maintain them within the operating pressure range. The operating pressures of the pressure vessels are: phase change pressure vessel (C3) > gaseous working fluid pressure vessel (C2) > liquid working fluid pressure vessel (C1).

[0042] In the following embodiments, liquid nitrogen is used as an example of a liquid phase working fluid, and the corresponding gas phase working fluid is gaseous nitrogen.

[0043] The first pressure vessel is equipped with a first pressure sensor (i.e., liquid working fluid pressure sensor C1-1) to obtain a first current pressure. The controlled elements on the fourth pipeline are a fourth pressure control element (i.e., cryoablation working pressure control element L4-3) and a fourth solenoid valve (i.e., boost solenoid valve L4-2), connected in series between the second and first pressure vessels. The fourth solenoid valve opens when the first current pressure reaches a preset first pressure value, connecting the second and first pressure vessels. The fourth pressure control element automatically controls its output pressure to be less than its input pressure. The second pressure vessel primarily serves to compensate for the increased pressure within the first pressure vessel. Of course, if the first pressure vessel is overpressured, it also requires pressure relief. In one embodiment, the first pressure vessel is equipped with exhaust and pressure relief pipelines, each equipped with a solenoid valve (i.e., pressure relief solenoid valve L3-2) that opens at a preset pressure to relieve pressure.

[0044] Automatic pressure control for the first pressure vessel:

[0045] The working pressure of the liquid working fluid pressure vessel (C1) is maintained within a desired range through a cryoablation working pressure reducing pipe (L3), a cryoablation working pressure boosting pipe (L4), and a liquid working fluid pressure sensor (C1-1); the liquid working fluid pressure sensor (C1-1) collects a first current pressure of the liquid working fluid pressure vessel (C1), and the first current pressure is used to determine whether the working pressure of the liquid working fluid pressure vessel (C1) is within the desired range.

[0046] The working pressure is the nominal pressure of the liquid working fluid pressure vessel (C1), and the working pressure range is the pressure interval of the liquid working fluid pressure vessel (C1) corresponding to the nominal pressure. The pressure interval takes the working pressure as the median, and there is an upper deviation relative to the median as the upper limit of the pressure interval, and there is a lower deviation relative to the median as the lower limit of the pressure interval. Different working pressures of the liquid working fluid pressure vessel (C1) correspond to their corresponding pressure intervals, that is, the working pressure range.

[0047] When the pressure collected by the liquid working fluid pressure sensor (C1-1) drops to a first boost opening threshold, the cryoablation working pressure boost solenoid valve (L4-2) in the cryoablation working pressure boost pipeline (L4) opens, and the gaseous working fluid in the gaseous working fluid pressure vessel (C2) enters the liquid working fluid pressure vessel (C1) through the cryoablation working pressure boost pipe (L4-1) for boosting; when the pressure collected by the liquid working fluid pressure sensor (C1-1) is higher than a first boost closing threshold, the cryoablation working pressure boost solenoid valve (L4-2) in the cryoablation working pressure boost pipeline (L4) closes.

[0048] The working pressure of the liquid working fluid pressure vessel (C1) is dynamically maintained within the working pressure range. When the pressure collected by the liquid working fluid pressure sensor (C1-1) is higher than the first pressure reduction opening threshold, the cryoablation working pressure pressure reducing solenoid valve (L3-2) in the cryoablation working pressure pressure reducing pipeline (L3) is opened, and the gaseous working fluid in the liquid working fluid pressure vessel (C1) is discharged to the atmosphere through the cryoablation working pressure pressure reducing pipe (L3-1) for pressure reduction; when the pressure collected by the liquid working fluid pressure sensor (C1-1) is lower than the first pressure reduction closing threshold, the cryoablation working pressure pressure reducing solenoid valve (L3-2) in the cryoablation working pressure pressure reducing pipeline (L3) is closed.

[0049] When the first boost opening threshold, the first boost closing threshold, the first decompression opening threshold and the first decompression closing threshold are reached, the working pressure of the liquid working fluid pressure vessel (C1) is dynamically maintained within the working pressure range; the first boost opening threshold is less than the first boost closing threshold; the first decompression opening threshold is greater than the first decompression closing threshold; the lower limit of the working pressure range of the liquid working fluid pressure vessel (C1) is less than the first boost opening threshold; and the upper limit of the working pressure range of the liquid working fluid pressure vessel (C1) is greater than the first decompression opening threshold.

[0050] In one embodiment, the second pressure vessel is equipped with a second pressure sensor (i.e., gaseous working fluid pressure sensor C2-1) to obtain a second current pressure. The controlled elements on the fifth pipeline are a fifth solenoid valve (i.e., gaseous working fluid output solenoid valve L5-4) and a fifth pressure control element (i.e., gaseous working fluid output pressure control element L5-5), which are connected in series between the third and second pressure vessels. The fifth solenoid valve opens when the second current pressure falls below a preset second pressure value, connecting the third and second pressure vessels. The fifth pressure control element automatically controls its output pressure to be lower than its input pressure. Of course, if the second pressure vessel is overpressured, it also requires pressure reduction. In one embodiment, the second pressure vessel is equipped with an exhaust pressure relief pipeline equipped with a solenoid valve (i.e., gaseous working fluid pressure relief valve C2-2) that opens at a preset pressure to relieve pressure.

[0051] The automatic control of the second pressure vessel is:

[0052] The working pressure of the gaseous working fluid pressure vessel (C2) is dynamically maintained within a working pressure range through a gaseous working fluid output pipeline (L5), a gaseous working fluid pressure sensor (C2-1), and a gaseous working fluid pressure relief valve (C2-2); the gaseous working fluid pressure sensor (C2-1) collects a second current pressure of the gaseous working fluid pressure vessel (C2), and the second current pressure is used to determine whether the working pressure of the gaseous working fluid pressure vessel (C2) is within a desired range.

[0053] The working pressure of the gaseous working medium pressure vessel (C2) is dynamically maintained within the working pressure range. When the pressure sensed by the gaseous working medium pressure sensor (C2-1) drops to a second boost opening threshold, the gaseous working medium output solenoid valve (L5-4) in the gaseous working medium output pipeline (L5) opens, and the gaseous working medium in the phase change pressure vessel (C3) enters the gaseous working medium pressure vessel (C2) through the gaseous working medium output pipe (L5-1) and after being decompressed by the gaseous working medium output pressure control element (L5-5), thereby compensating for the boost pressure of the second pressure vessel. When the pressure sensed by the gaseous working medium pressure sensor (C2-1) exceeds a second boost closing threshold, the gaseous working medium output solenoid valve (L5-4) in the gaseous working medium output pipeline (L5) closes.

[0054] The working pressure of the gaseous working fluid pressure vessel (C2) is dynamically maintained within the working pressure range. When the pressure collected by the gaseous working fluid pressure sensor (C2-1) is higher than the second pressure reduction opening threshold, the gaseous working fluid pressure relief valve (C2-2) opens, and the gaseous working fluid pressure vessel (C2) is discharged to the atmosphere through the gaseous working fluid pressure relief valve (C2-2) to reduce pressure. When the pressure collected by the gaseous working fluid pressure sensor (C2-1) is lower than the second pressure reduction closing threshold, the gaseous working fluid pressure relief valve (C2-2) is closed.

[0055] The second boost opening threshold, the second boost closing threshold, the second decompression opening threshold and the second decompression closing threshold dynamically maintain the working pressure of the gaseous working medium pressure vessel (C2) within the working pressure range; the second boost opening threshold is less than the second boost closing threshold; the second decompression opening threshold is greater than the second decompression closing threshold; the lower limit of the working pressure range of the gaseous working medium pressure vessel (C2) is less than the second boost opening threshold; and the upper limit of the working pressure range of the gaseous working medium pressure vessel (C2) is greater than the second decompression opening threshold.

[0056] In one embodiment, a third pressure sensor (i.e., a phase change pressure transmitter L5-2) for monitoring the third pressure vessel is provided on the fifth pipeline (i.e., the gaseous working medium output pipeline L5) to obtain a third current pressure. A heating device (i.e., a phase change heating device C3-2) is provided on the third pressure vessel to heat the liquid working medium in the third pressure vessel to change the phase into a gaseous working medium and increase the third current pressure. When the third current pressure reaches a third preset pressure value, the heating device stops heating.

[0057] In this embodiment, the third pressure vessel is equipped with a liquid level sensor (C3-4) and a temperature sensor (C3-5) to obtain a third current liquid level and a third current temperature. The third current liquid level and the third current temperature are used to determine the control of the heating device. When the third current liquid level and the third current temperature meet the expected conditions, the heating device stops heating.

[0058] See Figure 2One end of a gaseous working medium output pipe (L5) fixed to the top end cap of the liquid working medium pressure vessel (C1) extends into the phase change pressure vessel (C3). The bottom of the phase change pressure vessel (C3) is provided with a liquid working medium one-way flow device (C3-1), which can be understood as being located below the liquid level in the first pressure vessel. The liquid working medium in the liquid working medium pressure vessel (C1) can enter the phase change pressure vessel (C3) through the liquid working medium one-way flow device (C3-1). The liquid working medium one-way flow device (C3-1) prevents liquid or gaseous working medium from entering the liquid working medium pressure vessel (C1) from the phase change pressure vessel (C3). The phase change heating device (C3-2) is located in the phase change pressure vessel (C3). In order to avoid affecting the liquid working medium in the first vessel during the heating process, an isolation layer for isolating heat conduction (i.e., a vessel insulation layer (C3-3)) is provided on the third pressure vessel. The vessel insulation layer (C3-3) thermally isolates the phase change pressure vessel (C3) from the liquid working medium pressure vessel (C1).

[0059] Automatic pressure control of the third pressure vessel (i.e. phase change pressure vessel C3):

[0060] The gaseous working medium in the phase change pressure vessel (C3) can enter the gaseous working medium pressure vessel (C2) through the gaseous working medium output pipeline (L5).

[0061] The working pressure of the phase change pressure vessel (C3) is dynamically maintained within the working pressure range through the gaseous working medium output pipeline (L5), the liquid working medium one-way circulation device (C3-1), the phase change heating device (C3-2), the phase change pressure transmitter (L5-2), the liquid level sensor (C3-4) and the temperature sensor (C3-5); the phase change pressure transmitter (L5-2) collects the third current pressure of the phase change pressure vessel (C3), and the third current pressure is used to determine whether the working pressure of the phase change pressure vessel (C3) is within the expected range.

[0062] The working pressure of the phase change pressure vessel (C3) is dynamically maintained within the working pressure range. During the period when the pressure collected by the phase change pressure transmitter (L5-2) increases from the third boost opening threshold to the third boost closing threshold, the liquid level information of the liquid level sensor (C3-4) and the temperature information of the temperature sensor (C3-5) are used to determine whether the boosting process is effective:

[0063] During the period when the pressure collected by the phase change pressure transmitter (L5-2) is boosted from the third boost on threshold to the third boost off threshold, when the liquid level collected by the liquid level sensor (C3-4) is less than the first low liquid level threshold and the temperature collected by the temperature sensor (C3-5) is less than the first high temperature threshold, the pressure collected by the phase change pressure transmitter (L5-2) is greater than the third boost lower limit threshold, the boosting process ends, the phase change heating device (C3-2) stops heating, and the boosting process is valid; when the liquid level collected by the liquid level sensor (C3-4) is less than the first low liquid level threshold and the temperature collected by the temperature sensor (C3-5) is greater than the first high temperature threshold, the pressure collected by the phase change pressure transmitter (L5-2) is less than the third boost lower limit threshold, the boosting process ends, the phase change heating device (C3-2) stops heating, the boosting process is invalid, and the boosting process as described above is repeated.

[0064] Of course, during the entire pressure linkage process, the phase change pressure vessel (C3) is over-pressurized. Therefore, the third pressure vessel is provided with an exhaust pressure relief pipe, on which is provided an electromagnetic valve (i.e., the phase change vessel pressure relief electromagnetic valve (L5-3)) that opens at a preset pressure to implement pressure relief, so that the third current pressure is dynamically maintained within the working pressure range. In this embodiment, the phase change vessel pressure relief electromagnetic valve (L5-3) is provided on the gaseous working medium output pipe (L5-1). When the phase change pressure transmitter (L5-2 ) drops to the third pressure reduction opening threshold, the phase change container pressure relief solenoid valve (L5-3) in the gaseous working medium output pipeline (L5) opens, and the gaseous working medium in the phase change pressure vessel (C3) is discharged to the atmosphere through the gaseous working medium output pipe (L5-1) and the phase change container pressure relief solenoid valve (L5-3), thereby reducing the pressure. When the pressure collected by the phase change pressure transmitter (L5-2) drops to the third pressure reduction closing threshold, the phase change container pressure relief solenoid valve (L5-3) in the gaseous working medium output pipeline (L5) closes.

[0065] The third boost opening threshold, the first liquid level closing threshold, the third boost closing threshold, the first low liquid level threshold, the first high temperature threshold, the third boost lower limit threshold, the third pressure reduction opening threshold and the third pressure reduction closing threshold dynamically maintain the working pressure of the phase change pressure vessel (C3) within the working pressure range; the third boost opening threshold < the third boost lower limit threshold < the third boost closing threshold; the third pressure reduction opening threshold > the third pressure reduction closing threshold; the lower limit of the working pressure range of the phase change pressure vessel (C3) < the third boost opening threshold; the upper limit of the working pressure range of the phase change pressure vessel (C3) > the third pressure reduction opening threshold; the first liquid level closing threshold > the first low liquid level threshold; the first high temperature threshold ≤ room temperature; the first low liquid level threshold, the first high temperature threshold and the third boost lower limit threshold participate in the judgment of the pressurization effectiveness of the phase change pressure vessel (C3).

[0066] The working pressure of the liquid working medium pressure vessel (C1), the working pressure of the gaseous working medium pressure vessel (C2), the working pressure of the phase change pressure vessel (C3), the first boost opening threshold, the first boost closing threshold, the first decompression opening threshold, the first decompression closing threshold, the second boost opening threshold, the second boost closing threshold, the second decompression opening threshold, the second decompression closing threshold, the third boost opening threshold, the first liquid level closing threshold, the third boost closing threshold, the first low liquid level threshold, the first high temperature threshold, the third boost lower limit threshold, the third decompression opening threshold and the third decompression closing threshold are dynamically maintained within their respective working pressure ranges.

[0067] The working pressure of the pressure vessel is dynamically maintained within the working pressure range. The cryoablation working pressure boost solenoid valve (L4-2), the gaseous working fluid output solenoid valve (L5-4), and the phase change container pressure relief solenoid valve (L5-3) participate in the pressure boosting process of the pressure vessel; the cryoablation working pressure reducing solenoid valve (L3-2), the gaseous working fluid pressure relief valve (C2-2), and the phase change container pressure relief solenoid valve (L5-3) participate in the pressure relief process of the pressure vessel; it is prohibited for the cryoablation working pressure boost solenoid valve (L4-2) and the cryoablation working pressure reducing solenoid valve (L3-2) to operate at the same time; it is prohibited for the gaseous working fluid output solenoid valve (L5-4) and the gaseous working fluid pressure relief valve (C2-2) to operate at the same time.

[0068] The working pressure range of each pressure vessel is dynamic. The specific range setting method is:

[0069] See Figure 1 The cryoablation equipment and the second pressure vessel are connected through the seventh pipeline (i.e., the return air recovery pipeline L7) and the eighth pipeline (i.e., the system flow monitoring and recovery condition control pipeline L8). The eighth pipeline is equipped with a system flow monitoring and recovery condition control flowmeter (L8-4), and the setting of the working pressure range can be adjusted according to the flow data of the system flow monitoring and recovery condition control flowmeter (L8-4) in the system flow monitoring and recovery condition control pipeline (L8).

[0070] In one embodiment, the second pressure vessel delivers heated gaseous working fluid to the cryoablation device via the sixth pipeline (i.e., the replacement and rewarming pipeline L6) to displace air and moisture within the cryoablation device before operation. The working fluid for the second pressure vessel originates from the third pressure vessel and the cryoablation device. The gaseous working fluid output from the third pressure vessel is heated by a phase change heating device, while the working fluid from the cryoablation device is heated by a system flow monitoring and recovery condition control heat exchanger (L8-2) located on the eighth pipeline.

[0071] The working fluid pressure vessel system for cryoablation of the present application recycles the nitrogen generated by the cryoablation equipment and stores it in a gaseous working fluid pressure vessel. The pressure of the gaseous working fluid pressure vessel is controlled to remain stable by a phase change pressure vessel and a pressure reducing exhaust pipeline used to heat liquid nitrogen to generate nitrogen. The pressure of the gaseous working fluid pressure vessel is controlled by an output pressure control element to maintain the pressure of the liquid working fluid pressure vessel at the working pressure, thereby realizing automatic cycle control of the pressure. At the same time, the first pressure vessel relies on the pressure compensation of the second pressure vessel, and thus cryoablation can be performed at a lower working pressure, reducing the safety risks of surgery.

[0072] See attached Figure 1 An embodiment of the present application discloses a low-pressure fluid system for enhancing the performance of interventional cryoablation, which adopts the pressure control system of the above-mentioned embodiment, wherein the low-pressure fluid system includes at least one of the following: a liquid working fluid pressure vessel (C1), a gaseous working fluid pressure vessel (C2), a phase change pressure vessel (C3), a liquid refrigerant output pipeline (L1), a pre-cooling fluid recovery pipeline (L2), a cryoablation working pressure reducing pipeline (L3), a cryoablation working pressure boosting pipeline (L4), a gaseous working fluid output pipeline (L5), a replacement and rewarming pipeline (L6), a return gas recovery pipeline (L7), a system flow monitoring and recovery condition control pipeline (L8), a vacuum degree creation pipeline (L9) and a cryoablation device (CP) as an interventional ablation device.

[0073] The modules, containers, pipelines, and related equipment and methods described above are applicable to low-pressure cryoablation, for example, less than 3 MPa (e.g., operating pressure of approximately 0.5 MPa). Each module can independently perform certain unit operations and, in some cases, can be integrated into a more complete low-pressure fluid system. The following describes each component separately, but does not strictly require them to be configured simultaneously:

[0074] 1) Pressure vessels for accommodating liquid and gaseous working fluids: liquid working fluid pressure vessel (first pressure vessel C1), gaseous working fluid pressure vessel (second pressure vessel C2), and phase change pressure vessel (third pressure vessel C3).

[0075] ① A first pressure vessel (C1) stores a liquid working medium therein and is connected to the cryoablation device CP via a first pipeline L1 to transport the liquid working medium;

[0076] The first pressure vessel C1 is connected to the second pressure vessel C2 through a fourth pipeline L4; a third pressure vessel C3 is provided in the first pressure vessel C1, which can change the liquid phase working medium into the gas phase working medium.

[0077] The first pressure vessel C1 is provided with a third pipeline L3 for exhaust and pressure relief;

[0078] The liquid working fluid pressure vessel (C1), preferably a Dewar pressure vessel, is used to store the liquid working fluid during the freezing process in a cryoablation procedure; and comprises: a liquid working fluid pressure sensor (C1-1) and a liquid working fluid level sensor (C1-2).

[0079] ② A gaseous working medium pressure vessel (i.e., a second pressure vessel C2), wherein the second pressure vessel (C2) stores a gaseous working medium therein and is connected to the first pressure vessel (C1) via a fourth pipeline L4 and delivers the gaseous working medium to the first pressure vessel (C1);

[0080] The second pressure vessel (C2) is connected to the third pressure vessel (C3) via a fifth pipeline (L5) and receives the gaseous working medium from the third pressure vessel (C3);

[0081] The second pressure vessel (C2) is connected to the cryoablation device (CP) via a sixth pipeline (L6) and transports the heated gaseous working medium;

[0082] The second pressure container (C2) is connected to the cryoablation device (CP) and / or the gaseous working medium of the first pipeline (L1) through an eighth pipeline (L8).

[0083] The preferred embodiment is a Dewar pressure vessel, which is used to store gaseous working fluids used in pre-displacement, rewarming process and return gas channel recovery during cryoablation procedures; and comprises: a gaseous working fluid pressure sensor (C2-1) and a gaseous working fluid pressure relief valve (C2-2).

[0084] ③The phase change pressure vessel (i.e., the third pressure vessel C3) is connected to and transported to the second pressure vessel (C2) through the fifth pipeline (L5).

[0085] It is used to change the phase of liquid working fluid into gaseous working fluid, and then transport the phase-changed gas through the gaseous working fluid output pipeline (L5) and the pressure control element (L5-5) to the gaseous working fluid pressure vessel (C2). It includes: a liquid working fluid one-way flow device (C3-1), a phase change heating device (C3-2), a vessel insulation layer (C3-3), a liquid level sensor (C3-4), and a temperature sensor (C3-5).

[0086] 2) Nine functional pipelines including valves, sensors and control elements: liquid refrigerant output pipeline (first pipeline L1), pre-cooling fluid recovery pipeline (second pipeline L2), cryoablation working pressure reduction pipeline (third pipeline L3), cryoablation working pressure boosting pipeline (fourth pipeline L4), gaseous working fluid output pipeline (fifth pipeline L5), replacement and rewarming pipeline (sixth pipeline L6), return air recovery pipeline (seventh pipeline L7), system flow monitoring and recovery condition control pipeline (eighth pipeline L8), and vacuum creation pipeline (ninth pipeline L9).

[0087] ① A conveying device comprising the above embodiment, wherein the liquid refrigerant output pipeline (first pipeline L1) is used to transmit the liquid working medium, comprising:

[0088] Liquid refrigerant pipe (L1-1); liquid refrigerant output valve (L1-2); safety pressure relief valve (L1-3); and liquid refrigerant output pipeline pressure transmitter (L1-4) and temperature sensor (L1-5) involved in closed-loop control, used to monitor the state parameters of the fluid entering the flexible cryoprobe; liquid refrigerant output one-way valve (L1-6) to prevent backflow.

[0089] ② A gaseous working medium flows through the interior of the pre-cooling fluid recovery pipeline (i.e., the second pipeline (L2), one end of the second pipeline (L2) is connected to the first pipeline (L1), and the other end is connected to the eighth pipeline (L8) and is finally transported to the second pressure vessel (C2).

[0090] The second pipeline (L2) is used to transmit the fluid working medium to the system flow monitoring and recovery condition control pipeline (L8) during the pre-cooling process in the cryoablation procedure, and includes:

[0091] Pre-cooling fluid recovery tube (L2-1); pre-cooling fluid recovery solenoid valve (L2-2), which opens the heat exchanger during the cryoablation procedure and closes after reaching the pre-cooling temperature threshold range; pre-cooling fluid recovery one-way valve (L2-3) to prevent backflow.

[0092] ③ A cryoablation working pressure reducing pipeline (i.e., the third pipeline (L3), which is connected to the first pressure vessel (C1) and is used to release the pressure of the liquid working medium Dewar pressure vessel (C1). It includes:

[0093] A cryoablation working pressure reducing pipe (L3-1); a cryoablation working pressure reducing solenoid valve (L3-2), which opens when the pressure of the liquid working medium in the liquid nitrogen working medium pressure container (C1) exceeds the release pressure threshold, and closes when the pressure falls below the release pressure threshold.

[0094] ④ A cryoablation working pressure boosting pipeline (i.e., the fourth pipeline (L4), which connects the first pressure vessel (C1) and the second pressure vessel (C2), and is used to input the gaseous working medium in the gaseous working medium pressure vessel (C2) into the liquid working medium Dewar pressure vessel (C1) for pressurization, including:

[0095] A cryoablation operating pressure booster tube (L4-1); a cryoablation operating pressure booster solenoid valve (L4-2) opens when the liquid working fluid pressure in the liquid nitrogen working fluid pressure vessel (C1) falls below the boost pressure threshold, and closes when it rises above the boost pressure threshold. A cryoablation operating pressure control element (L4-3) participates in closed-loop control and is used to adjust the cryoablation operating pressure.

[0096] ⑤ The gaseous working medium output pipeline (i.e., the fifth pipeline (L5) connects the third pressure vessel (C3) and the second pressure vessel (C2) and is used to input the gaseous working medium in the phase change pressure vessel (C3) into the gaseous working medium pressure vessel (C2) for pressurization, including:

[0097] Gaseous working medium output pipe (L5-1), pressure monitoring element of phase change pressure vessel (C3): phase change pressure transmitter (L5-2); phase change vessel pressure relief solenoid valve (L5-3), which is opened to empty the gaseous working medium in the phase change pressure vessel (C3), or to create a pressure difference between the liquid working medium pressure vessel (C1) and the phase change pressure vessel (C3), so that the liquid working medium enters the phase change pressure vessel (C3) from the liquid working medium pressure vessel (C1), and is closed when liquid working medium enters; when the pressure threshold of the phase change pressure transmitter (L5-2) is higher than the gaseous working medium output pressure threshold, the gaseous working medium output solenoid valve (L5-4) is opened, otherwise it is closed; the gaseous working medium output pressure control element (L5-5) is used to adjust the pressure in the gaseous working medium pressure vessel (C2).

[0098] ⑥ The replacement and rewarming pipeline (i.e., the sixth pipeline (L6) connects the second pressure vessel (C2) and the cryoablation device (CP) and is used to selectively heat the gaseous working medium in the gaseous working medium pressure vessel (C2) and then transport it to the cryoablation device (CP) during the replacement process in the cryoablation procedure, including:

[0099] Replacement and rewarming tube (L6-1); replacement and rewarming solenoid valve (L6-2), which opens when in the replacement process of the cryoablation procedure and closes after the replacement process, and is used to replace the air in the cryoablation equipment; opens when in the rewarming process of the cryoablation procedure, and at the same time the replacement and rewarming heat exchanger (L6-3) is started, and is used to heat the gas working medium in the replacement and rewarming tube (L6-1) to reach the threshold temperature, and at the same time the rewarming temperature sensor (L6-4) participates in the rewarming process, and cooperates to adjust the heating power of the replacement and rewarming heat exchanger (L6-2) so that the gas working medium in the replacement and rewarming tube (L6-1) reaches the threshold temperature; replacement and rewarming one-way valve (L6-5) is used to prevent backflow.

[0100] ⑦ The return gas recovery pipeline (i.e., the seventh pipeline (L7) has one end connected to the cryoablation device (CP) and the other end connected to the eighth pipeline (L8), which is used to transport the return gas generated during the freezing process during the cryoablation procedure to the system flow monitoring and recovery condition control pipeline (L8), including:

[0101] Return air recovery pipe (L7-1); return air recovery pipe one-way valve (L7-2) to prevent backflow.

[0102] ⑧ The system flow monitoring and recovery condition control pipeline (i.e., one end of the eighth pipeline (L8) is connected to the seventh pipeline (L7) and the second pipeline (L2) at the same time, and the other end is connected to the second pressure vessel (C2), which is used to heat the fluid working medium flowing from the pre-cooling fluid recovery pipeline (L2) during the pre-cooling process in the cryoablation procedure and then pump it to the gaseous working medium pressure vessel (C2). In addition, during the freezing process in the cryoablation procedure, the fluid working medium flowing from the return gas recovery pipeline (L7) is heated and then pumped to the gaseous working medium pressure vessel (C2) after the flow rate is measured by a flow meter; the measured flow rate participates in the pressure control of the system. Including:

[0103] System flow monitoring and recovery condition control pipe (L8-1); System flow monitoring and recovery condition control heat exchanger (L8-2), used to heat the fluid flowing in from the pre-cooling fluid recovery pipe (L2) during the pre-cooling process in the cryoablation procedure and make it reach the threshold temperature; and the fluid flowing in from the return air recovery pipe (L7) during the freezing process in the cryoablation procedure and make it reach the threshold temperature; System flow monitoring and recovery condition control temperature sensor (L8-3) participates in closed-loop control and is used to cooperate with the adjustment of the heating power of the system flow monitoring and recovery condition control heat exchanger (L8-2), The fluid in the system flow monitoring and recovery condition control pipe (L8-1) reaches the threshold temperature. If the fluid cannot reach the threshold temperature after heating, the gas recovery release valve (L8-7) opens, releasing the fluid to the atmosphere. The system flow monitoring and recovery condition control flowmeter (L8-4) is primarily used to monitor the freezing process during the cryoablation procedure. The fluid flow entering the system flow monitoring and recovery condition control pipe (L8-1) from the return gas recovery pipe (L7-1) participates in closed-loop control, predicting the cryoablation effect and coordinating pressure regulation to ensure the desired cryoablation effect. The system flow monitoring and recovery condition control extraction booster pump (L8-5) adjusts the suction power and operating pressure to further promote smooth gas return and achieve the desired cryoablation effect. The system flow monitoring and recovery condition control check valve (L8-6) prevents backflow.

[0104] ⑨The vacuum creation pipeline (i.e., the ninth pipeline L9) connects the cryoablation device (CP) and the vacuum device (L9-3) to create a high vacuum for the cryoablation device (CP) to achieve a good vacuum insulation effect, including:

[0105] Vacuum creation tube (L9-1); vacuum gauge (L9-2) is used to monitor whether the vacuum degree reaches the threshold requirement; vacuum creation pump group is used to create high vacuum degree, and the flexible freezing probe has good vacuum insulation effect.

[0106] 3) Cryoablation device (CP) containing temperature sensor and heating element.

[0107] ① Cryoablation device (CP) is used to enter the human body through natural cavities and perform cryoablation procedures on lesions, including:

[0108] A structure used to enhance interventional cryoablation performance; the cryoablation device's distal thermocouple (CP1) monitors the temperature within the cryoprobe and participates in closed-loop control; and the cryoablation device's distal nickel-chromium wire is used for the rewarming process during the cryoablation procedure. The cryoablation device can be, for example, a flexible cryoprobe.

[0109] The following combination Figures 3 to 8 Explain the workflow of the low-pressure fluid system

[0110] The various steps in the figure are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the figure may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

[0111] 1) The system starts, initializes, and reads the control threshold parameters stored in the memory; at the same time, it obtains the data of the system sensors.

[0112] 2) First, determine the liquid level in the liquid working medium Dewar pressure vessel (C1). LLC1-2_ Lower Limit is the low liquid level warning threshold of the vessel. Execute the judgment procedure:

[0113] If the current liquid level of the liquid working fluid level sensor (C1-2) is less than LLC1-2_Lower Limit, the system determines that the liquid level cannot sustain the current cryoablation procedure. In other words, LLC1-2_Lower Limit represents the liquid nitrogen volume required for one cryoablation procedure, including redundancy. The liquid nitrogen replenishment procedure is then executed. When LLC1-2_CL exceeds LLC1-2_Upper Limit, liquid nitrogen refilling is complete.

[0114] If the current liquid level LLC1-2_CL of the liquid working fluid level sensor (C1-2) is ≥ LLC1-2_ Lower Limit, the system considers that the cryoablation procedure can be performed.

[0115] 3) Determine the pressure inside the liquid working medium Dewar pressure vessel (C1), PC1_IWP is the pressure threshold at the time of initialization of the pressure vessel; execute the judgment procedure:

[0116] If the current pressure of the liquid working fluid pressure sensor (C1-1) is PC1-1_CP ≤ PC1_IWP, the system assumes that the pressure within the pressure vessel meets the initialization pressure requirement and can continue with subsequent procedures. PC1_IWP is the initialization pressure of the liquid working fluid Dewar pressure vessel (C1) before use in a cryoablation procedure. This pressure is typically the pressure of the liquid working fluid Dewar pressure vessel (C1) when it is not in use. Note: The initialization pressure of the pressure vessel, PC1_IWP, must be less than the operating pressure of the liquid working fluid Dewar pressure vessel, PC1_WP.

[0117] If the current pressure of the liquid working fluid pressure sensor (C1-1) PC1-1_CP>PC1_IWP, the pressure relief procedure is executed, and the cryoablation working pressure relief solenoid valve (L3-2) is opened to relieve the pressure until PC1-1_CP≤PC1_IWP.

[0118] 4) Determine the pressure inside the gaseous working medium pressure vessel (C2). PC2_IWP is the pressure threshold value during initialization of the pressure vessel. Execute the determination procedure:

[0119] If the current pressure PC2-1_CP of the gaseous working fluid pressure sensor (C2-1) is ≤PC2_IWP, the system considers that the pressure in the pressure vessel meets the pressure requirements at the time of initialization and can continue to execute subsequent procedures; PC2_IWP is the initialization pressure of the gaseous working fluid pressure vessel (C2) before the cryoablation procedure is used. This pressure is usually the gaseous working fluid stored in the gaseous working fluid pressure vessel (C2) after the last cryoablation procedure; since the gas in the gaseous working fluid pressure vessel (C2) is the gas recovered during the pre-cooling process and the cryoablation process, the gas will be output during the rewarming process. In order to ensure normal recovery during the pre-cooling and cryoablation processes for the next surgery, the pressure PC2_IWP is less than the working pressure PC2_WP of the gaseous working fluid pressure vessel (C2).

[0120] If the current pressure of the gaseous working medium pressure sensor (C2-1) PC2-1_CP>PC2_IWP, the pressure relief procedure is executed, and the gaseous working medium pressure relief valve (C2-2) is opened to relieve the pressure until PC2-1_CP≤PC2_IWP.

[0121] 5) Determine the pressure inside the phase change pressure vessel (C3). PC3_IWP is the pressure threshold at the time of initialization of the pressure vessel. Execute the determination procedure:

[0122] If the current pressure PL5-2_CP of the phase change pressure transmitter (L5-2) is less than or equal to PC3_IWP, the system will determine that the pressure inside the pressure vessel meets the initialization pressure requirement and can continue to execute subsequent procedures. This pressure PC3_IWP is less than the working pressure PC3_WP inside the phase change pressure vessel (C3).

[0123] If the current pressure PL5-2_CP of the phase change pressure transmitter (L5-2) is greater than PC3_IWP, the pressure relief procedure is executed and the phase change container pressure relief solenoid valve (L5-3) is opened to relieve the pressure until PL5-2_CP ≤ PC3_IWP.

[0124] 6) Determine whether the current pressure PL5-2_CP of the phase-change pressure transmitter (L5-2) is greater than the current pressure PC2-1_CP of the gaseous working fluid pressure sensor (C2-1). The gaseous working fluid output solenoid valve (L5-4) is opened, and the output pressure of the gaseous working fluid output pressure control element (L5-5) is set to PL5-5_SP_OUT > PC2-1_CP. At this point, the gaseous working fluid in the phase-change pressure vessel (C3) enters the gaseous working fluid pressure vessel (C2). This continues until PL5-2_CP - PC2-1_CP < ΔP0, meaning the current pressure in the phase-change pressure vessel (C3) equals the pressure in the gaseous working fluid pressure vessel (C2). The gaseous working fluid output solenoid valve (L5-4) is closed, and the output of the gaseous working fluid output pressure control element (L5-5) is shut off. This utilizes the gaseous working fluid in the phase-change pressure vessel (C3), improving its efficiency.

[0125] 7-1) Open the liquid refrigerant outlet valve (L1-2), starting the cryoablation precooling process. All components in the precooling fluid recovery pipeline (L2) and the system flow monitoring and recovery condition control pipeline (L8) enter operation. Open the precooling fluid recovery solenoid valve (L2-2), and the system flow monitoring and recovery condition control heat exchanger (L8-2) will start.

[0126] The system flow monitoring and recovery condition control flowmeter (L8-4) and the system flow monitoring and recovery condition control extraction booster pump (L8-5) have fluid temperature restrictions. Therefore, the system sets temperature thresholds: TL8-2_ET_ Lower Limit: The first heat exchange temperature of the system flow monitoring and recovery condition control heat exchanger; and TL8-2_ET_ Upper Limit: The second heat exchange temperature of the system flow monitoring and recovery condition control heat exchanger; these thresholds correspond to the lower and upper limits of the temperature range, respectively.

[0127] If: The current fluid temperature collected by the system flow monitoring and recovery condition control temperature sensor (L8-3):

[0128] TL8-3_CT≥TL8-2_ET_ Lower Limit&&TL8-3_CT≤TL8-2_ET_ Upper Limit; the gas working medium recovery release valve (L8-7) is closed, and the fluid passes through the system flow monitoring and recovery condition control flowmeter (L8-4) and the system flow monitoring and recovery condition control extraction booster pump (L8-5) into the gaseous working medium pressure vessel (C2) for pressurization.

[0129] If TL8-3_CT < TL8-2_ET_ Lower Limit || TL8-3_CT > TL8-2_ET_ Upper Limit, the gas working medium recovery and release valve (L8-7) opens. The fuzzy self-tuning PID temperature control algorithm is invoked to adjust the temperature to meet the conditions TL8-3_CT ≥ TL8-2_ET_ Lower Limit && TL8-3_CT ≤ TL8-2_ET_ Upper Limit. The gas working medium recovery and release valve (L8-7) closes, and the fluid flows through the system flow monitoring and recovery condition control flowmeter (L8-4) and the system flow monitoring and recovery condition control extraction booster pump (L8-5) into the gas working medium pressure vessel (C2) for pressurization.

[0130] The cyclic pressurization of the above steps reaches the event: the current temperature TL1-5_CT - TL1-5_PT pre-cooling threshold temperature collected by the liquid refrigerant output pipe temperature sensor (L1-5) is less than △T0||(or) the current pressure of the gaseous working fluid pressure sensor (C2-1) of the second pressurization closing pressure PC2_PB_CV-PC2-1_CP of the gaseous working fluid pressure vessel (C2) is less than △P0.

[0131] If TL1-5_CT - TL1-5_PT < △T0 occurs in the above OR logic, it indicates that the pre-cooling process is completed, the liquid refrigerant output valve (L1-2) is closed, and the system delay device is started. The delay interval △t is set so that after the liquid refrigerant output valve (L1-2) is closed, the residual fluid in the liquid refrigerant output pipeline (L1) and the pre-cooling fluid recovery pipeline (L2) enters the gaseous working fluid pressure vessel (C2); then the system flow monitoring and recovery condition control extraction booster pump (L8-5) are turned off.

[0132] If TL1-5_CT - TL1-5_PT < △T0 is false in the above OR logic, then the event PC2_PB_CV - PC2-1_CP < △P0 must have occurred. The pressure in the gaseous working fluid pressure vessel (C2) has reached the boosting requirement. Therefore, the system flow monitoring and recovery condition control extraction booster pump (L8-5) are shut down. The gas working fluid recovery release valve (L8-7) is opened to discharge the fluid in the pipeline into the atmosphere until the event TL1-5_CT - TL1-5_PT < △T0 occurs, meeting the pre-cooling condition.

[0133] Then close the liquid refrigerant output valve (L1-2), start the system delay device, and delay the interval △t so that after the liquid refrigerant output valve (L1-2) is closed, the residual fluid in the liquid refrigerant output pipeline (L1) and the pre-cooling fluid recovery pipeline (L2) enters the gaseous working fluid pressure vessel (C2); then close the system flow monitoring and recovery condition control extraction booster pump (L8-5).

[0134] Next, the pressure condition of the gaseous working fluid pressure vessel (C2) is judged. When the current pressure of the gaseous working fluid pressure sensor (C2-1) is less than △P0 (the second pressure reduction opening threshold PC2_RP_OV - PC2-1_CP), the gaseous working fluid pressure relief valve (C2-2) is opened to relieve pressure. The gaseous working fluid pressure relief valve (C2-2) is closed until the current pressure of the gaseous working fluid pressure sensor (C2-1) is less than △P0 (the second pressure reduction closing threshold PC2-1_CP - PC2_RP_CV).

[0135] 7-2) Determine whether the current pressure PL5-2_CP of the phase change pressure transmitter (L5-2) is ≥ PC1-1_CP and the current pressure PC1-1_CP of the liquid working fluid pressure sensor (C1-1); open the phase change container pressure relief solenoid valve (L5-3); and when the current pressure PL5-2_CP–atm of the phase change pressure transmitter (L5-2) is < △P0 and the first liquid level closing threshold LLC3-4_CV– LLC3-4_CL of the liquid level sensor (C3-4) is < △L0; close the phase change container pressure relief solenoid valve (L5-3) and start the phase change heating device (C3-2) to heat.

[0136] If it is determined that the current pressure PL5-2_CP of the phase change pressure transmitter (L5-2) is less than PC1-1_CP and the current liquid level value LLC3-4_CL of the phase change pressure vessel (C3) liquid level sensor (C3-4) is less than the first low liquid level threshold of LLC3-4_Lower Limit liquid level sensor (C3-4), the phase change vessel pressure relief solenoid valve (L5-3) is opened. When the current pressure PL5-2_CP–atm of the phase change pressure transmitter (L5-2) is less than △P0 and the first liquid level closing threshold LLC3-4_CV–LLC3-4_CL of the liquid level sensor (C3-4) is less than △L0, the phase change vessel pressure relief solenoid valve (L5-3) is closed, and the phase change heating device (C3-2) starts heating.

[0137] 7-2-2) If it is determined that the current pressure PL5-2_CP of the phase change pressure transmitter (L5-2) is less than PC1-1_CP and the current liquid level value LLC3-4_CL of the liquid level sensor (C3-4) of the phase change pressure vessel (C3) is greater than or equal to the first low liquid level threshold of the liquid level sensor (C3-4), the phase change heating device (C3-2) starts heating.

[0138] After the phase-change heating device (C3-2) is started, if the current pressure PL5-2_CP of the phase-change pressure transmitter (L5-2) exceeds the third boost lower limit threshold (PC3_PB_Lower Limit), and the current temperature TC3-5_CT collected by the temperature sensor (C3-5) is less than TC3-5_Upper Limit, the temperature sensor (C3-5) reaches the first high temperature threshold; the phase-change heating device (C3-2) continues heating.

[0139] Until: the current temperature TC3-5_CT collected is greater than or equal to the first high temperature threshold of the temperature sensor (C3-5) or the third boost shutdown threshold PC3_PB_CV-PL5-2_CP, and the current pressure of the variable pressure transmitter (L5-2) is less than △P0; the heating device (C3-2) stops heating.

[0140] If the current pressure PL5-2_CP of the phase change pressure transmitter (L5-2) is less than or equal to the third boost lower limit threshold (PC3_PB_Lower Limit) and the current temperature TC3-5_CT collected by the temperature sensor (C3-5) is greater than or equal to the first high temperature threshold (TC3-5_Upper Limit) of the temperature sensor (C3-5), heating is stopped, the current boost is invalidated, and the boost process is restarted. Otherwise, heating continues until one of the above judgment conditions is met.

[0141] When the device meets the requirements and the current temperature TC3-5_CT collected by the temperature sensor (C3-5) ≥ TC3-5_UpperLimit the first high temperature threshold of the temperature sensor (C3-5) or the third boost closing threshold PC3_PB_ CV-PL5-2_CP the current pressure of the pressure transmitter (L5-2) < △P0, the output program is executed. The gaseous working medium output solenoid valve (L5-4) opens, and the output pressure of the gaseous working medium output pressure control element (L5-5) is set to: PL5-5_SP_OUT>PC2-1_CP; at this time, the gaseous working medium in the phase change pressure vessel (C3) enters the gaseous working medium pressure vessel (C2); until the third boost opening threshold value of the variable pressure transmitter (L5-2) PL5-2_CP-PC3_PB_OV is less than △P0|| (or) the current pressure of the variable pressure transmitter (L5-2) PL5-2_CP - PC2-1_CP The current pressure of the gaseous working medium pressure sensor (C2-1) is less than △P0<. This limit is determined by the controller. When the gaseous working medium pressure vessel (C2) is gradually pressurized, PC2-1_CP will gradually increase. However, the pressure controller requires that the upstream pressure should be greater than the downstream pressure, so this logic should be provided here>|| (or) the second boost closing pressure of the gaseous working medium pressure vessel (C2) PC2_ When the current pressure of the PB_ CV - PC2-1_ CP gaseous working fluid pressure sensor (C2-1) is less than △P0, the gaseous working fluid output solenoid valve (L5-4) is closed and the gaseous working fluid output pressure control element (L5-5) is turned off.

[0142] The above-mentioned pressurization process may be multiple cycles until the event: the second pressurization closing pressure PC2_PB_CV of the gaseous working medium pressure container (C2) - PC2-1_CP current pressure of the gaseous working medium pressure sensor (C2-1) is less than △P0 occurs, indicating that the initialization pressurization process of the gaseous working medium pressure container (C2) is completed.

[0143] To prevent the pressure in phase-change pressure vessel C3 from being too high when stopped, a pressure relief check is introduced: when the current pressure of the phase-change pressure transmitter (L5-2) (PL5-2_CP - PC3_RP_OV) and the third pressure reduction opening threshold of the phase-change pressure vessel (C3) are less than △P0, the phase-change vessel pressure relief solenoid valve (L5-3) is opened. When the current pressure of the phase-change pressure transmitter (L5-2) (PL5-2_CP - PC3_RP_CV) and the third pressure reduction closing threshold of the phase-change pressure vessel (C3) are less than △P0, the phase-change vessel pressure relief solenoid valve (L5-3) is closed. This prevents excessive pressure in C3.

[0144] Next, the pressure condition of the gaseous working fluid pressure vessel (C2) is judged. When the current pressure of the gaseous working fluid pressure sensor (C2-1) is less than △P0 (the second pressure reduction opening threshold PC2_RP_OV - PC2-1_CP), the gaseous working fluid pressure relief valve (C2-2) is opened to relieve pressure. The gaseous working fluid pressure relief valve (C2-2) is closed until the current pressure of the gaseous working fluid pressure sensor (C2-1) is less than △P0 (the second pressure reduction closing threshold PC2-1_CP - PC2_RP_CV).

[0145] 8) After the above process, the gaseous working medium pressure vessel (C2) has met its working pressure requirements: PC2_WP; the phase change pressure vessel (C3) has also met its working pressure requirements; PC3_WP; the liquid refrigerant output pipeline (L1) has been fully pre-cooled.

[0146] Therefore, it meets the requirements of the subsequent cryoablation procedure, detects or connects the system consumables, and enters the steps of building pressure of the liquid working fluid Dewar pressure vessel (C1) and replacing the gas inside the consumables after the system is connected to the consumables.

[0147] 9) Open the replacement and rewarming solenoid valve (L6-2) to initiate the replacement process. The purpose of this replacement process is to replace the air and moisture in the consumables' internal piping with the gaseous working fluid in the gaseous working fluid pressure vessel (C2) before the freezing process. The replacement and rewarming heat exchanger (L6-3) is activated, and after a fuzzy self-tuning PID temperature control algorithm, the temperature of the replacement gas is raised to room temperature, satisfying the condition TL6-4_CT – room temperature < △T0. The gas passes through the return gas recovery pipeline (L7) and enters the system flow monitoring and recovery condition control pipeline (L8). It then enters the gaseous working fluid pressure vessel (C2) using a recovery process similar to the pre-cooling process, as follows:

[0148] The system flow monitoring and recovery condition control flowmeter (L8-4) and the system flow monitoring and recovery condition control extraction booster pump (L8-5) have fluid temperature restrictions. Therefore, the system sets temperature thresholds: TL8-2_ET_ Lower Limit: The first heat exchange temperature of the system flow monitoring and recovery condition control heat exchanger; and TL8-2_ET_ Upper Limit: The second heat exchange temperature of the system flow monitoring and recovery condition control heat exchanger; these thresholds correspond to the lower and upper limits of the temperature range, respectively.

[0149] If: The current fluid temperature collected by the system flow monitoring and recovery condition control temperature sensor (L8-3):

[0150] TL8-3_CT≥TL8-2_ET_ Lower Limit&&TL8-3_CT≤TL8-2_ET_ Upper Limit; the gas working medium recovery release valve (L8-7) is closed, and the fluid passes through the system flow monitoring and recovery condition control flowmeter (L8-4) and the system flow monitoring and recovery condition control extraction booster pump (L8-5) into the gaseous working medium pressure vessel (C2) for pressurization.

[0151] If TL8-3_CT < TL8-2_ET_ Lower Limit || TL8-3_CT > TL8-2_ET_ Upper Limit, the gas working medium recovery and release valve (L8-7) opens. The fuzzy self-tuning PID temperature control algorithm is invoked to adjust the temperature to meet the conditions TL8-3_CT ≥ TL8-2_ET_ Lower Limit && TL8-3_CT ≤ TL8-2_ET_ Upper Limit. The gas working medium recovery and release valve (L8-7) closes, and the fluid flows through the system flow monitoring and recovery condition control flowmeter (L8-4) and the system flow monitoring and recovery condition control extraction booster pump (L8-5) into the gas working medium pressure vessel (C2) for pressurization.

[0152] This replacement process is output from the gaseous working medium pressure vessel (C2) and then flows back to the gaseous working medium pressure vessel (C2). This process does not cause a sharp change in pressure, so no pressure judgment is performed during this process. In addition, the entire replacement process is maintained for a time of △t1.

[0153] The replacement process is completed and Probe_ZH_Flag is sent.

[0154] 10) Raise the pressure of the liquid working fluid dewar pressure vessel (C1) to the working pressure; open the cryoablation working pressure boost solenoid valve (L4-2); set the output pressure PL4-3_SP_OUT of the cryoablation working pressure control element (L4-3) to be greater than the first boost initialization closing threshold PC1_PB_CV; thereby causing the gaseous working fluid pressure vessel (C2) to boost the pressure of the liquid working fluid dewar pressure vessel (C1) through the cryoablation working pressure boost pipeline (L4) until: the first boost initialization closing threshold PC1_PB_CV - PC1-1_CP liquid working fluid pressure sensor (C1-1)

[0155] The collected current pressure is less than △P0, indicating that the liquid working medium Dewar pressure vessel (C1) has been pressurized, the cryoablation working pressure boosting solenoid valve (L4-2) is closed, and the cryoablation working pressure control element (L4-3) is turned off.

[0156] The pressure buildup before ablation of the liquid working medium Dewar pressure vessel (C1) is completed, and PC1_PreCyro_Flag is sent.

[0157] 11-1) When the event Probe_ZH_Flag == 1 & PC1_PreCyro_Flag == 1 occurs, cryoablation is ready. Wait for the event Probe_Cyro_Star == 1; set the cryoablation delay timer to △t2; open the liquid cryogen outlet valve (L1-2); and start cryoablation timer timer2. When the cryoablation delay reaches △t2, the freezing process for this cycle ends, and the number of freezing cycles during the cryoablation process is Cryo_Cycle++. Then, close the liquid cryogen outlet valve (L1-2). The freezing process for this cryoablation cycle ends.

[0158] 11-2) The rewarming process of the cryoablation cycle begins, and the displacement and rewarming heat exchanger (L6-3) is activated. The fuzzy self-tuning PID temperature control algorithm is used to set the rewarming gas temperature to the following: TL6-4_CT < TL6-3_RW_ Upper Limit && TL6-3_RW_ Lower Limit < TL6-4_CT. Then, rewarming timer 3 is started. When the rewarming duration during cryoablation reaches △t3, the number of cycles (Cryo_Cycle++) is reset. Solenoid valve L6-2 is then closed, and the displacement and rewarming heat exchanger (L6-3) is turned off.

[0159] After a freezing and thawing cycle, determine the event:

[0160] Cryo_Cycle==Cryo_Set&&ReWarm_Cycle==RW_Set

[0161] When this occurs, it indicates that the freezing cycle is finished; otherwise, the cryoablation procedure will continue.

[0162] 11-3) In the above process, the recovery process is executed, and the gas passes through the return air recovery pipeline (L7) and then enters the system flow monitoring and recovery condition control pipeline (L8).

[0163] Then, the gas enters the gaseous working medium pressure vessel (C2) using a recovery process similar to the pre-cooling process, as follows:

[0164] The system flow monitoring and recovery condition control flow meter (L8-4) and the system flow monitoring and recovery condition control extraction booster pump (L8-5) have limits on fluid temperature, so the system sets temperature thresholds: TL8-2_ET_ Lower Limit: the first heat exchange temperature of the system flow monitoring and recovery condition control heat exchanger and TL8-2_ET_ Upper Limit: the second heat exchange temperature of the system flow monitoring and recovery condition control heat exchanger; respectively

[0165] Corresponds to the lower limit of the temperature range and the upper limit of the temperature range.

[0166] If the current fluid temperature collected by the system flow monitoring and recovery condition control temperature sensor (L8-3) is: TL8-3_CT ≥ TL8-2_ET_ Lower Limit && TL8-3_CT ≤ TL8-2_ET_ Upper Limit; the gas working fluid recovery release valve (L8-7) is closed, and the fluid enters the gas working fluid pressure vessel (C2) for pressurization through the system flow monitoring and recovery condition control flowmeter (L8-4) and the system flow monitoring and recovery condition control extraction booster pump (L8-5).

[0167] If: TL8-3_CT<TL8-2_ET_ Lower Limit || TL8-3_CT>TL8-2_ET_ Upper Limit; the gas working medium recovery release valve (L8-7) is opened.

[0168] The fuzzy self-tuning PID temperature control algorithm is invoked to ensure that the temperature satisfies TL8-3_CT ≥ TL8-2_ET_ Lower Limit && TL8-3_CT ≤ TL8-2_ET_ Upper Limit. The gas recovery release valve (L8-7) is then closed, and the fluid flows through the system flow monitoring and recovery condition control flowmeter (L8-4) and the system flow monitoring and recovery condition control extraction booster pump (L8-5) into the gaseous working fluid pressure vessel (C2) for pressurization. If the event PC2_PB_CV-PC2-1_CP<△P0 occurs, the recovered fluid no longer enters the gaseous working fluid pressure vessel (C2) and is discharged to the atmosphere via the bypass. If the event PC2_PB_CV-PC2-1_CP<△P0 occurs, the recovered fluid no longer enters the gaseous working fluid pressure vessel (C2) and is discharged to the atmosphere via the bypass.

[0169] Cryo_Cycle==Cryo_Set&&ReWarm_Cycle==RW_Set

[0170] When it occurs, it indicates that the freezing cycle is finished, otherwise it continues to execute.

[0171] When cryoablation begins, the vacuum device (L9-3) starts working and the vacuum degree is set to Vaccum; until the cryoablation procedure is completed.

[0172] The technical features of the above-described embodiments may be combined in any manner. To simplify the description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as no contradiction exists between these combinations of technical features, they should be considered to be within the scope of this specification. When technical features of different embodiments are embodied in the same drawing, it can be deemed that the drawing also discloses examples of combinations of the various embodiments involved.

[0173] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A working fluid pressure vessel system for cryoablation, characterized in that: It includes a first pressure vessel, a second pressure vessel and a third pressure vessel, wherein The first pressure vessel is used to store liquid working fluid and supply the liquid working fluid to the cryoablation device during the ablation process; The second pressure vessel is used to store gaseous working fluid and is in controlled communication with the first pressure vessel through a fourth pipe, while receiving reflux working fluid from the cryoablation device; The third pressure vessel is arranged in the first pressure vessel and is used to change the phase of the liquid working medium into the gaseous working medium. The third pressure vessel is controllably connected to the first pressure vessel through a one-way flow device to receive the liquid working medium. The third pressure vessel is equipped with a heating device to heat the liquid working medium in the third pressure vessel to change the phase into the gaseous working medium and increase the third current pressure. The third pressure vessel is also controllably connected to the second pressure vessel through a fifth pipeline. The fifth pipeline is equipped with a third pressure sensor for monitoring the third pressure vessel to obtain the third current pressure. The third pressure vessel is equipped with an exhaust pressure relief pipeline. Controlled elements are respectively arranged on the fourth pipeline and the fifth pipeline. Each controlled element and the one-way flow device are opened and closed accordingly under expected conditions, so that the pressures of the first pressure vessel, the second pressure vessel and the third pressure vessel are correlated.

2. The working fluid pressure vessel system for cryoablation according to claim 1, characterized in that: The first pressure vessel is equipped with a first pressure sensor for obtaining a first current pressure; The controlled elements on the fourth pipeline are a fourth pressure control element and a fourth solenoid valve connected in series in sequence between the second pressure vessel and the first pressure vessel; The fourth solenoid valve opens when the first current pressure reaches a first preset pressure value, connecting the second pressure container and the first pressure container, and the fourth pressure control element automatically controls its own output pressure to be lower than its own input pressure.

3. The working fluid pressure vessel system for cryoablation according to claim 1, characterized in that: The second pressure vessel is provided with a second pressure sensor for obtaining a second current pressure; The controlled elements on the fifth pipeline are a fifth solenoid valve and a fifth pressure control element which are sequentially connected in series between the third pressure vessel and the second pressure vessel; The fifth solenoid valve opens when the second current pressure is lower than the second pressure preset value, connecting the third pressure container and the second pressure container, and the fifth pressure control element automatically controls its own output pressure to be lower than its own input pressure.

4. The working fluid pressure vessel system for cryoablation according to claim 1, characterized in that: When the third current pressure reaches a third preset pressure value, the heating device stops heating.

5. The working fluid pressure vessel system for cryoablation according to claim 4, characterized in that: The third pressure vessel is provided with a liquid level sensor and a temperature sensor for obtaining a third current liquid level and a third current temperature; When the third current liquid level and the third current temperature meet the expected conditions, the heating device stops heating.

6. The working fluid pressure vessel system for cryoablation according to claim 4, characterized in that: The third pressure vessel is provided with an isolation layer for isolating heat conduction.

7. The working fluid pressure vessel system for cryoablation according to claim 5, characterized in that: The second pressure vessel delivers the heated gaseous working medium to the cryoablation device through a sixth pipeline, so as to replace the air and moisture inside the cryoablation device before the cryoablation device works.

8. The working fluid pressure vessel system for cryoablation according to claim 5, characterized in that: When the third current pressure and the third current liquid level meet the expected conditions, the one-way flow device works to receive the liquid working medium from the first pressure container.

9. The working fluid pressure vessel system for cryoablation according to claim 1, characterized in that: The one-way flow device is arranged at the bottom of the third pressure container and is below the liquid level in the first pressure container.

10. The working fluid pressure vessel system for cryoablation according to claim 1, characterized in that: The first pressure vessel and the second pressure vessel are respectively provided with an exhaust pressure relief pipe, and each of the exhaust pressure relief pipes is respectively provided with a solenoid valve which opens at a preset pressure to implement pressure relief.

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