Working fluid pre-cooling system for cryoablation

Abstract

The present application provides a working fluid pre-cooling system for cryoablation, comprising a first pressure vessel, a second pressure vessel, a first pipeline, and a second pipeline. The first pressure vessel is used to store liquid-phase cryogenic working fluid; the second pressure vessel is used to store gaseous working fluid; the second pipeline is connected between the first pressure vessel and the second pressure vessel; the first pipeline is connected between the first pressure vessel and the cryoablation device to transport the liquid-phase cryogenic working fluid to the cryoablation device during the ablation process. The first pipeline has an inner and outer double-layer structure. During pre-cooling, the liquid-phase cryogenic working fluid flows from the first pressure vessel through the inner layer of the first pipeline, the outer layer of the first pipeline, the second pipeline, and finally to the second pressure vessel. This system can effectively reduce the vaporization of the working fluid caused by temperature differences and eliminate air blockage. The working fluid in the outer layer acts as an isolation layer to limit heat exchange between the working fluid in the inner layer and the air, thereby extending the cryoablation time. Corresponding pipelines for recovering the working fluid are also provided, which is environmentally friendly and economical.

Description

Technical Field

[0001] The present application relates to the technical field of medical devices, and in particular to a working fluid pre-cooling 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] The existing phase change cooling method using liquid refrigerant is prone to cause "air blockage" in the pipeline or cooling ablation equipment, which ultimately leads to failure of cryoablation and seriously affects the safety of the operation. Summary of the Invention

[0005] The present application discloses a working fluid pre-cooling system for cryoablation, which can reduce the occurrence of gas blockage.

[0006] The present application provides a working fluid pre-cooling system for cryoablation, comprising:

[0007] a first pressure vessel, the first pressure vessel being used to store a liquid-phase refrigeration working medium;

[0008] A second pressure vessel; the second pressure vessel is used to store a gaseous working medium;

[0009] a second pipeline connected between the first pressure vessel and the second pressure vessel;

[0010] The first pipeline is connected between the first pressure vessel and the cryoablation device and is used to transport liquid-phase cryogenic working medium to the cryoablation device during the ablation process. The first pipeline has an inner and outer double-layer structure. During pre-cooling, the liquid-phase cryogenic working medium flows from the first pressure vessel through the inner layer of the first pipeline, the outer layer of the first pipeline, the second pipeline, and finally to the second pressure vessel.

[0011] 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.

[0012] Optionally, the end of the first pipe adjacent to the first pressure vessel is the first end, and the end of the first pipe adjacent to the cryoablation device is the second end;

[0013] The inner layer of the first pipe is connected to the first pressure container at a first end and to the cryoablation device at a second end;

[0014] The outer layer of the first pipe is connected to the second pipe at a first end, and is connected to the inner layer of the first pipe at a second end.

[0015] Optionally, a first output valve is disposed on the first pipeline, the first output valve having an output channel connected to the inner layer and a return channel connected to the outer layer, and the opening and closing of the first output valve controls the opening and closing of the output channel and the return channel;

[0016] The second pipeline is provided with a second solenoid valve for controlling the on-off of the second pipeline.

[0017] Optionally, the first pressure vessel is provided with a first liquid level sensor for obtaining a first current liquid level. When the first current liquid level meets a preset condition, the first output valve is allowed to open.

[0018] Optionally, a first temperature sensor is disposed on the first pipe adjacent to the second end, for obtaining a first current temperature of the inner layer;

[0019] When the first current temperature meets a preset condition, the first output valve and the second solenoid valve are closed.

[0020] Optionally, a safety pressure relief valve is arranged on the outer layer of the first pipeline.

[0021] Optionally, during pre-cooling, the liquid-phase freezing working fluid also enters the cryoablation device from the second end of the inner layer of the first pipe, and the working fluid pre-cooling system also includes a seventh pipe. The liquid-phase freezing working fluid flows from the first pressure vessel through the inner layer of the first pipe, the cryoablation device, the seventh pipe, and finally to the second pressure vessel.

[0022] Optionally, the second pressure vessel is connected to the first pressure vessel through a fourth pipe, and a controlled element is arranged on the fourth pipe. The controlled element is opened and closed accordingly under expected conditions, so that the pressures between the first pressure vessel and the second pressure vessel are balanced.

[0023] Optionally, the seventh pipeline and the second pipeline are connected to the second pressure vessel via a booster pump to increase the pressure of the working fluid in the seventh pipeline and the second pipeline and then deliver it to the second pressure vessel.

[0024] Optionally, a first temperature sensor is disposed on the first pipe adjacent to the second end, for obtaining a first current temperature of the inner layer;

[0025] When the first current temperature meets a preset condition, the boost pump is shut down with a delay.

[0026] The precooling system provided in the present application precools the first pipeline before cryoablation to prevent the working fluid from being vaporized due to temperature difference during cryoablation, and can also recycle the working fluid used for precooling. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of the low-pressure fluid system of this application (part of which is a schematic diagram of the pre-cooling system);

[0028] Figure 2 Schematic diagram of the liquid refrigerant tube-in-tube structure;

[0029] Figure 3 This is a structural diagram of a liquid refrigerant pipe gas-liquid separation device;

[0030] Figure 4 This is a schematic diagram of the structure of the liquid refrigerant output valve;

[0031] Figure 5 Schematic diagram of the liquid refrigerant tube structure;

[0032] Figure 6 Schematic diagram of the phase change pressure vessel structure;

[0033] Figures 7 to 12 This is a method flow chart. The connection relationship between the various figures can be seen from the corresponding labels at the boundary parts. DETAILED DESCRIPTION

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] Current liquid nitrogen cryoablation systems use supercritical pressure transmission to solve the "gas blockage" problem. However, the operating pressure of this type of cryoablation system is too high, posing a safety hazard. In addition, the system has high material requirements for equipment such as liquid nitrogen transmission pipelines, resulting in high costs.

[0039] Combine Figure 1The present application provides a working fluid pre-cooling 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), a first pipeline (i.e., a liquid refrigerant output pipeline L1), and a second pipeline (i.e., a pre-cooling fluid recovery pipeline L2). The first pressure vessel is used to store liquid-phase refrigerant, the second pressure vessel is used to store gaseous-phase refrigerant, and the second pipeline is connected between the first and second pressure vessels. The first pipeline is connected between the first pressure vessel and a cryoablation device (CP) to deliver liquid-phase refrigerant to the cryoablation device during the ablation process. The first pipeline has an inner and outer double-layer structure. During pre-cooling, the liquid refrigerant flows from the first pressure vessel through the inner layer of the first pipeline (i.e., the inlet channel L1-1-3), the outer layer of the first pipeline (i.e., the return channel L1-1-2), the second pipeline, and finally to the second pressure vessel. As can be seen, one end of the second pipeline is connected to the outer layer of the first pipeline, allowing the working fluid to cool the entire inner layer of the first pipeline before flowing to the second pressure vessel for recovery. The cooling method of the pre-cooling system of the present application is to rely on liquid cryogenic working fluid to cool the inner layer, outer layer, etc. that it passes through, and the pre-cooling can be stopped until the temperature of at least the inner layer meets the preset conditions. When performing cryoablation, the temperature difference between the inner layer and the working fluid is reduced or equal to 0 compared with the existing cryoablation technology during the process of the corresponding working fluid being output from the inner layer to the cryoablation device, which greatly reduces the vaporization amount of the liquid cryogenic working fluid, eliminates the gas blockage phenomenon, and improves the stability and safety of the operation. In addition, the working fluid in the outer layer can form an isolation layer to block the heat exchange between the inner layer working fluid and the air outside the first pipe, thereby extending the time of the cryoablation operation.

[0040] It should be noted here that the state change of the working fluid before or after entering the second pressure vessel is not the focus, but the flow path of the working fluid. For example, the working fluid in the pre-cooling process can be recovered to the second pressure vessel for storage, which is environmentally friendly.

[0041] The end of the first pipe adjacent to the first pressure vessel is designated as the first end, and the end adjacent to the cryoablation device is designated as the second end. The inner layer of the first pipe connects to the first pressure vessel at the first end and to the cryoablation device at the second end. The outer layer of the first pipe connects to the second pipe at the first end and to the inner layer of the first pipe at the second end. The isolation layer covers the entire inner layer, further reducing the amount of working fluid vaporized.

[0042] In one embodiment, a first output valve (i.e., liquid refrigerant output valve L1-2) is disposed on the first pipeline. The first output valve has an output channel (L1-2-1) connected to the inner layer and a return channel (L1-2-2) connected to the outer layer. The opening and closing of the first output valve controls the opening and closing of the output channel and the return channel. The liquid refrigerant output valve (L1-2) includes two pairs of input-output channels: a first input-output channel (corresponding to output channel L1-2-1) and a second input-output channel (corresponding to return channel L1-2-2). The first input-output channel communicates with the liquid refrigerant pipe inlet channel (L1-1-3), while the second input-output channel communicates with the liquid refrigerant pipe return channel (L1-1-2). The first input-output channel is used to supply liquid refrigerant, while the second input-output channel is used to pre-cool the valve body of the liquid refrigerant output valve (L1-2). When the liquid refrigerant output valve (L1-2) is in an open state, the fluid in the liquid refrigerant tube inlet channel (L1-1-3) of the liquid refrigerant tube (L1-1) dynamically flows into and out of the first input-output channel.

[0043] In this embodiment, a second solenoid valve (i.e., pre-cooling fluid recovery solenoid valve L2-2) is configured on the second pipeline to control the on / off state of the second pipeline. During the pre-cooling sequence of the cryoablation process, the pre-cooling fluid recovery solenoid valve (L2-2) is in an open state, and the reflux fluid in the liquid refrigerant tube reflux channel (L1-1-2) dynamically flows into and out of the second input-output channel. After the pre-cooling sequence of the cryoablation process is completed, the pre-cooling fluid recovery solenoid valve (L2-2) is in a closed state, and the reflux fluid in the liquid refrigerant tube reflux channel (L1-1-2) stops flowing, and the fluid in the second input-output channel stops flowing.

[0044] In one embodiment, the first pressure vessel is equipped with a first liquid level sensor for obtaining a first current liquid level. When the first current liquid level meets a preset condition, the first output valve is allowed to open, thereby preventing flow interruption during pre-cooling or cryoablation.

[0045] In another embodiment, a first temperature sensor is arranged on the first pipe near the second end to obtain the first current temperature of the inner layer. Preferably, the first current temperature is the temperature of the inner layer at the first end. When the first current temperature meets the preset conditions, the pre-cooling ends and the first output valve and the second solenoid valve are closed.

[0046] In one embodiment, a safety pressure relief valve (L1-3) is disposed on the outer layer of the first pipe. During the pre-cooling process of the cryoablation procedure, the reflux fluid in the liquid cryogen tube reflux channel (L1-1-2) flows dynamically. After the pre-cooling process of the cryoablation procedure is completed, the reflux fluid in the liquid cryogen tube reflux channel (L1-1-2) stops flowing. After the reflux fluid in the liquid cryogen tube reflux channel (L1-1-2) stops flowing, the fluid pressure in this layer should be limited to an operating pressure range. The safety pressure relief valve (L1-3) prevents the pressure in the liquid cryogen tube reflux channel (L1-1-2) from being too high. When the pressure exceeds the threshold pressure of the liquid cryogen tube reflux channel, the safety pressure relief valve (L1-3) opens and releases pressure. When the pressure falls below the threshold pressure of the liquid cryogen tube reflux channel, the safety pressure relief valve (L1-3) closes.

[0047] In another embodiment, during pre-cooling, the liquid refrigerant also enters the cryoablation device from the second end of the inner layer of the first pipe. The refrigerant pre-cooling system also includes a seventh pipe (i.e., a return air recovery pipe L7). The liquid refrigerant flows from the first pressure vessel, sequentially through the inner layer of the first pipe, the cryoablation device, the seventh pipe, and finally to the second pressure vessel. This also cools the internal piping of the cryoablation device to prevent air blockage within the device. Similarly, the refrigerant from the pre-cooling process is recovered to the second pressure vessel.

[0048] In one embodiment, the second pressure vessel is connected to the first pressure vessel via a fourth pipeline (i.e., the cryoablation working pressure boosting pipeline L4). A controlled element is configured on the fourth pipeline. The controlled element switches on and off accordingly under desired conditions to balance the pressures between the first and second pressure vessels. The desired condition is that when the first current pressure in the first pressure vessel falls below a preset value, the fourth pipeline is connected, allowing the gaseous working fluid in the second pressure vessel to flow into the first pressure vessel, maintaining the pressure of the first pressure vessel within the operating pressure range and enabling continuous output of the liquid-phase cryogenic working fluid. The controlled elements are a fourth pressure control element and a fourth solenoid valve, connected in series between the second and first pressure vessels. When the first current pressure reaches the first preset pressure value, the fourth solenoid valve opens, connecting the second and first pressure vessels. The fourth pressure control element automatically controls its output pressure to be lower than its input pressure.

[0049] The seventh and second pipelines are connected to the second pressure vessel via a booster pump (L8-5), which increases the pressure of the working fluid within the seventh and second pipelines before delivering it to the second pressure vessel. This allows the working fluid to circulate. At the end of pre-cooling (when the first current temperature meets a preset condition), the booster pump is delayed in shutting off. This allows the working fluid in the second and seventh pipelines to be recovered before cryoablation. This delayed shutdown can be achieved by setting a system delay within the system.

[0050] The present invention's fluid precooling system for cryoablation is a modification of the existing cryoablation system, dividing the first pipeline used to transport the working fluid into an inner and outer layer. This precooling system effectively reduces the amount of working fluid vaporized during the cryoablation process, eliminating air blockage. Furthermore, the working fluid in the outer layer acts as an isolation layer, limiting heat exchange between the working fluid in the inner layer and the air outside the first pipeline. This prolongs the cryoablation period, particularly during cryoablation procedures, and improves stability and safety. Furthermore, a corresponding pipeline for recovering the working fluid is added, contributing to environmental conservation.

[0051] Combine Figures 1 to 6 The present application provides a gas-liquid separation device. First, the inner and outer layer structures of the first pipeline in the above embodiment can be understood as including an outer tube (L1-1-4) and an isolation sleeve (L1-1-5) in the outer tube. The outer tube and the isolation sleeve constitute a liquid refrigerant tube (L1-1). The isolation sleeve divides the first pipeline into an inner and outer double-layer structure in the radial direction.

[0052] The gas-liquid separation device is a cylindrical structure housed within an isolation sleeve. The first end of the cylindrical structure is open, while the second end is closed. The interior of the cylindrical structure defines a first channel (i.e., the gas-liquid separation device base tube L1-1-4-2). A second channel is formed between the outer wall of the cylindrical structure and the inner wall of the isolation sleeve. A through hole (i.e., the vent L1-1-4-3) is provided in the sidewall of the cylindrical structure, connecting the first and second channels. Due to the presence of the through hole, some of the working fluid enters the first channel, and the mass flow rate of this two-phase flow is higher than the mass flow rate of the liquid. The gas-liquid two-phase flow that flows through the second channel and does not enter the liquid refrigerant tube (L1-1-4-2) within the gas-liquid separation device base tube has a higher mass flow rate of the liquid than the gas. This reduces the amount of working fluid vaporized in the second channel, lowering the probability of gas blockage during pre-cooling or ablation. Because the second end of the gas-liquid separation device is closed, working fluid entering the first channel flows toward the first end, in the opposite direction of the working fluid flow in the second channel. Combined with further analysis of the flow path of the working fluid in the first path, the flow path of the working fluid is also divided into two paths: the third path passes through the second channel to the cryoablation device or the outer layer; the fourth path passes through the second channel, the through hole, the first channel to the first end of the first channel.

[0053] In this embodiment, the working fluid stored in the first pressure vessel is liquid nitrogen, which reduces the proportion of liquid nitrogen vaporized due to temperature influences, and at the same time separates the nitrogen vaporized due to unavoidable factors such as friction from the liquid nitrogen, avoids gas blockage, and makes the output liquid nitrogen dosage stable and controllable, thereby achieving a stable cryoablation effect.

[0054] A method for reducing gas blockage may be to reduce the temperature difference between the inner layer temperature and the working medium during cryoablation. For example, in another embodiment, the liquid refrigerant tube (L1-1) is a tube-in-tube structure, including at least two or more tube-in-tube structures; it has: a liquid refrigerant tube thermal insulation channel, a liquid refrigerant tube return channel (L1-1-2), a liquid refrigerant tube inlet channel (L1-1-3), and a liquid refrigerant tube gas-liquid separation device (L1-1-4). The three channels, from the outside to the inside, divide the liquid refrigerant tube (L1-1) into a thermal insulation channel (L1-1-1), a return channel (L1-1-2), and an inlet channel (L1-1-3). The thermal insulation channel can be connected to the return channel (L1-1-2) and flow through the same working medium, or it can be disconnected from the return channel (L1-1-2) and the inlet channel (L1-1-3) and flow through other low-temperature working medium, further blocking heat exchange. In other embodiments, heat exchange is blocked by providing an insulation layer on the outer layer.

[0055] The outer wall of the cylindrical structure is provided with a guide groove for forming a second channel. The guide groove connects the first end and the second end, so that the working medium can flow on the guide groove. In order to achieve effective gas-liquid separation, a through hole is provided on the groove wall of the guide groove. Among them, the outer wall of the cylindrical structure is in contact with the inner wall of the isolation sleeve, and the guide groove is a groove structure, so the working medium can only flow through the guide groove, and then the working medium must pass through the through hole, thereby improving the gas-liquid separation efficiency. In the cross section, the second channel is surrounded by the groove wall of the guide groove and the inner wall of the isolation sleeve, wherein the groove wall of the guide groove is arc-shaped and smooth, which reduces the heat generated by friction with the working medium. The through hole is opened at the bottom of the arc, and the shape of the through hole is circular, which is convenient for processing.

[0056] Combine Figure 3 To further improve separation efficiency, methods include spirally winding guide grooves around the outer wall of the cylindrical structure to form a spiral channel, extending the flow path of the working medium. Alternatively, multiple through-holes are arranged along the guide grooves. Each spiral winding of the guide grooves contains 1 to 8 through-holes, and these through-holes are evenly spaced around the circumference of the cylindrical structure.

[0057] In one embodiment, the first end of the isolation sleeve extends beyond the first end of the outer tube. This extended portion serves as a bottom tube and is at least long enough to extend below the liquid level within the first pressure vessel, enabling continuous delivery of liquid working fluid during pre-cooling and ablation. The first end of the outer tube is located outside the first pressure vessel, allowing the working fluid to be delivered from the first end of the inner layer, then flow through the second end and back to the first end of the outer layer, cooling most or all of the inner layer.

[0058] The first end of the cylindrical structure and the first end of the isolation sleeve are axially adjacent to each other. Mutually adjacent means that the first end of the gas-liquid separation device is also below the liquid level in the first pressure vessel. Therefore, when the working fluid is discharged, it directly enters the second channel for gas-liquid separation. The working fluid that enters the first channel can return to the first pressure vessel and be liquefied, achieving local circulation and saving resources.

[0059] Combine Figure 4 In one embodiment, an output valve (i.e., liquid refrigerant output valve L1-2) is disposed on the first pipeline. The output valve has an output channel (L1-2-1) connected to the inner layer and a return channel (L1-2-2) connected to the outer layer. The liquid refrigerant output valve (L1-2) includes two pairs of input-output channels, a first input-output channel (corresponding to the output channel) and a second input-output channel (corresponding to the return channel). The first input-output channel is connected to the liquid refrigerant pipe inlet channel (L1-1-3); the second input-output channel is connected to the liquid refrigerant pipe return channel (L1-1-2). When the liquid refrigerant output valve (L1-2) is in an open state, the fluid in the liquid refrigerant pipe inlet channel (L1-1-3) of the liquid refrigerant pipe (L1-1) dynamically flows into and out of the first input-output channel.

[0060] The gas-liquid separation device of the present application can increase the liquid content of the mass flow of the working fluid delivered to the cryoablation equipment, and further reduce the gas blockage phenomenon.

[0061] See attached Figure 1 An embodiment of the present application discloses a low-pressure fluid system for enhancing the performance of interventional cryoablation, comprising 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) serving as an interventional ablation device.

[0062] 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:

[0063] 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).

[0064] 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;

[0065] 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.

[0066] The first pressure vessel C1 is provided with a third pipeline L3 for exhaust and pressure relief;

[0067] 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).

[0068] 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);

[0069] 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);

[0070] The second pressure vessel (C2) is connected to the cryoablation device (CP) via a sixth pipeline (L6) and transports the heated gaseous working medium;

[0071] 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).

[0072] 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).

[0073] 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).

[0074] 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).

[0075] 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).

[0076] 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:

[0077] 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.

[0078] 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).

[0079] 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:

[0080] 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.

[0081] 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:

[0082] 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.

[0083] 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:

[0084] 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.

[0085] 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:

[0086] 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).

[0087] 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:

[0088] 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.

[0089] 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:

[0090] Return air recovery pipe (L7-1); return air recovery pipe one-way valve (L7-2) to prevent backflow.

[0091] 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:

[0092] 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.

[0093] 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:

[0094] 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.

[0095] 3) Cryoablation device (CP) containing temperature sensor and heating element.

[0096] ① Cryoablation device (CP) is used to enter the human body through natural cavities and perform cryoablation procedures on lesions, including:

[0097] 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.

[0098] The following combination Figures 7 to 12 Explain the workflow of the low-pressure fluid system

[0099] 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.

[0100] 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.

[0101] 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:

[0102] 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.

[0103] 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.

[0104] 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:

[0105] 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.

[0106] 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.

[0107] 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:

[0108] 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).

[0109] 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.

[0110] 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:

[0111] 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).

[0112] 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] If: The current fluid temperature collected by the system flow monitoring and recovery condition control temperature sensor (L8-3):

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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).

[0123] 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).

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] To prevent the pressure in phase-change pressure vessel C3 from being too high when stopped, a pressure relief check is introduced: if 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. If 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.

[0133] 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).

[0134] 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.

[0135] 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.

[0136] 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:

[0137] 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.

[0138] If: The current fluid temperature collected by the system flow monitoring and recovery condition control temperature sensor (L8-3):

[0139] 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.

[0140] 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.

[0141] 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.

[0142] The replacement process is completed and Probe_ZH_Flag is sent.

[0143] 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)

[0144] The collected current pressure is less than △P0, indicating that the liquid working medium Dewar pressure vessel (C1) is pressurized, the cryoablation working pressure boosting solenoid valve (L4-2) is closed, and the cryoablation working pressure control element (L4-3) is turned off.

[0145] The pressure buildup before ablation of the liquid working medium Dewar pressure vessel (C1) is completed, and PC1_PreCyro_Flag is sent.

[0146] 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.

[0147] 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.

[0148] After a freezing and thawing cycle, determine the event:

[0149] Cryo_Cycle==Cryo_Set&&ReWarm_Cycle==RW_Set

[0150] When this occurs, it indicates that the freezing cycle is finished; otherwise, the cryoablation procedure will continue.

[0151] 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).

[0152] Then, the gas enters the gaseous working medium pressure vessel (C2) using a recovery process similar to the pre-cooling process, as follows:

[0153] 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

[0154] Corresponds to the lower limit of the temperature range and the upper limit of the temperature range.

[0155] 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).

[0156] 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.

[0157] 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.

[0158] Cryo_Cycle==Cryo_Set&&ReWarm_Cycle==RW_Set

[0159] When it occurs, it indicates that the freezing cycle is finished, otherwise it continues to execute.

[0160] When cryoablation begins, the vacuum device (L9-3) starts working and the vacuum degree is set to Vaccum; until the cryoablation procedure is completed.

[0161] 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.

[0162] 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 pre-cooling system for cryoablation, characterized in that: include: a first pressure vessel, the first pressure vessel being used to store a liquid-phase refrigeration working medium; a second pressure vessel; The second pressure vessel is used to store gaseous working medium; a second pipeline, the second pipeline being connected between the first pressure vessel and the second pressure vessel, and an eighth pipeline being connected between the second pressure vessel and the second pipeline; A first pipeline, the first pipeline is connected between the first pressure vessel and the cryoablation device and is used to transport liquid-phase cryogenic working fluid to the cryoablation device during the ablation process. The first pipeline is a double-layer structure with an inner and outer layer. The end of the first pipeline adjacent to the first pressure vessel is the first end, and the end adjacent to the cryoablation device is the second end. The inner layer of the first pipeline is connected to the first pressure vessel at the first end and to the cryoablation device at the second end. The outer layer of the first pipeline is connected to the second pipeline at the first end and to the inner layer of the first pipeline at the second end. During pre-cooling, the liquid-phase cryogenic working fluid flows from the first pressure vessel through the inner layer of the first pipeline, the outer layer of the first pipeline, the second pipeline and the eighth pipeline in sequence to the second pressure vessel.

2. The working fluid pre-cooling system for cryoablation according to claim 1, characterized in that: The first pipe is provided with a first output valve, the first output valve having an output channel connected to the inner layer and a return channel connected to the outer layer, and the opening and closing of the first output valve controls the opening and closing of the output channel and the return channel; The second pipeline is provided with a second solenoid valve for controlling the on-off of the second pipeline.

3. The working fluid pre-cooling system for cryoablation according to claim 2, characterized in that: The first pressure container is equipped with a first liquid level sensor for obtaining a first current liquid level. When the first current liquid level meets a preset condition, the first output valve is allowed to open.

4. The working fluid pre-cooling system for cryoablation according to claim 2, characterized in that: A first temperature sensor is disposed on the first pipe adjacent to the second end, for obtaining a first current temperature of the inner layer; When the first current temperature meets a preset condition, the first output valve and the second solenoid valve are closed.

5. The working fluid pre-cooling system for cryoablation according to claim 2, characterized in that: A safety pressure relief valve is arranged on the outer layer of the first pipeline.

6. The working fluid pre-cooling system for cryoablation according to claim 1, characterized in that: A booster pump and a heat exchanger are arranged on the eighth pipeline. The booster pump is used to increase the pressure of the working fluid and then deliver it to the second pressure vessel. The heat exchanger is used to heat the working fluid and then pump it to the second pressure vessel.

7. The working fluid pre-cooling system for cryoablation according to claim 6, characterized in that: During pre-cooling, the liquid-phase freezing working fluid also enters the cryoablation device from the second end of the inner layer of the first pipeline. The working fluid pre-cooling system also includes a seventh pipeline. The liquid-phase freezing working fluid flows from the first pressure vessel through the inner layer of the first pipeline, the cryoablation device, the seventh pipeline, and finally to the second pressure vessel.

8. The working fluid pre-cooling system for cryoablation according to claim 7, characterized in that: The second pressure vessel is connected to the first pressure vessel through a fourth pipe. A controlled element is provided on the fourth pipe. The controlled element is turned on and off accordingly under expected conditions, so that the pressures between the first pressure vessel and the second pressure vessel are balanced.

9. The working fluid pre-cooling system for cryoablation according to claim 7, characterized in that: The seventh pipeline and the second pipeline are connected to the eighth pipeline and are connected to the second pressure vessel through the booster pump to increase the pressure of the working medium in the seventh pipeline and the second pipeline and then transport it to the second pressure vessel.

10. The working fluid pre-cooling system for cryoablation according to claim 9, characterized in that: A first temperature sensor is disposed on the first pipe adjacent to the second end, for obtaining a first current temperature of the inner layer; When the first current temperature meets a preset condition, the boost pump is shut down with a delay.

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