A liquid injection device and a thermal vapor ablation apparatus

Abstract

The application discloses a liquid injection device and a hot steam ablation device. The liquid injection device comprises a conveyor, a positioning seat for positioning the conveyor and a push injection mechanism. The conveyor comprises a barrel and a movable plug movably arranged in the barrel. The movable plug and the inner wall of the front end of the barrel form a containing cavity. The positioning seat is provided with a positioning structure. A limit sensor is arranged below the positioning structure. The push injection mechanism comprises a motor, a screw rod, a moving seat connected to the screw rod and a push rod horizontally connected to the moving seat. The push rod is coaxially arranged with the barrel. A pressure sensor is arranged between the tail of the push rod and the moving seat. The front end of the push rod acts on the movable plug. The hot steam ablation device comprises the above-mentioned liquid injection device. The application significantly improves the reliability of the installation detection of the conveyor, the accuracy and consistency of the push injection process, and has intelligent overload protection and abnormal diagnosis functions, thereby comprehensively enhancing the safety of clinical operation and treatment effect.

Description

Technical Field

[0001] This invention belongs to the field of medical device technology, and in particular relates to an injection device and a hot steam ablation device. Background Technology

[0002] In recent years, steam ablation technology based on thermal steam therapy equipment has received increasing attention. Taking the treatment of benign prostatic hyperplasia (BPH) as an example, by injecting high-temperature steam into the prostate tissue, the heat released during steam condensation ablates the lesions or hyperplastic tissue, thus maximizing the protection of surrounding normal tissue. Thermal steam therapy equipment typically includes a delivery system for pushing sterile water and a steam generator to vaporize the pushed sterile water. The injection device, as the core actuator for fluid delivery, directly affects the injection volume and speed control of steam, thereby determining the treatment effect and safety.

[0003] In the prior art, there are already related injection device solutions. For example, Chinese Invention Patent Publication No. CN120267394B discloses an injection device for a hot steam therapy device, which includes a syringe, an injection assembly, a force sensor, a syringe holder, a linear module, and a controller. In this solution, a positioning member is provided above the syringe holder, and the positioning member has a receiving chamber for accommodating the syringe. The chamber wall has at least two limiting portions protruding towards the center of the receiving chamber, and the syringe is limited between the corresponding two limiting portions. However, this prior art solution still has the following shortcomings: (1) There is a lack of electrical detection mechanism for the delivery device to be installed in place. The above scheme only uses the limiting part of the receiving chamber to mechanically position the syringe, and does not set up a special electrical detection element to confirm whether the syringe is installed in place. In this scheme, the control system cannot know the actual installation status of the syringe and only relies on the mechanical structure for positioning constraint. In clinical operation, if the syringe is not fully installed in place and the equipment starts to push the injection, it may cause safety problems such as the plunger being pushed dry, liquid leakage or plunger deviation. (2) Lack of flexible clamping compensation for the installation state of the delivery device. The limiting part of the above scheme is a rigid structure protruding towards the center of the receiving chamber. It has a rigid fit with the syringe. In particular, there are dimensional tolerances in the manufacturing process of the cylinder part. After long-term use, the surface of the positioning structure may be worn. The rigid limiting structure cannot adaptively compensate for these tolerances and wear, which leads to a decrease in the repeatability of the syringe after each installation, affecting the coaxial fit between the push rod and the syringe, and thus affecting the consistency and reliability of the injection.

[0004] Therefore, it is necessary to provide a liquid injection device and a hot steam ablation device to solve the above-mentioned technical problems. Summary of the Invention

[0005] The main objective of this invention is to provide an injection device that significantly improves the reliability of delivery device installation detection, the accuracy and consistency of the injection process, and has intelligent overload protection and abnormality diagnosis functions, thereby comprehensively enhancing the safety of clinical operations and the therapeutic effect.

[0006] The present invention achieves the above objective through the following technical solution: a liquid injection device, comprising: A conveyor, comprising a cylindrical body and a movable plug movably disposed inside the cylindrical body, wherein the movable plug and the inner wall of the front end of the cylindrical body form a receiving cavity; A positioning seat, wherein a positioning structure for positioning the conveyor is provided on the positioning seat, and a limit sensor is provided below the positioning structure; The injection mechanism includes a motor, a lead screw driven by the motor, a movable seat connected to the lead screw and reciprocating along a first direction, and a push rod horizontally connected to the movable seat. The first direction is the axial direction of the cylinder. The push rod is coaxially arranged with the cylinder and the outer diameter of the push rod is smaller than the inner diameter of the cylinder. A pressure sensor is provided between the tail of the push rod and the movable seat, and the front end of the push rod acts on the movable plug.

[0007] Furthermore, the conveyor also includes a liquid inlet / outlet head disposed at the front end of the cylinder and a push rod extending from the rear end of the cylinder into the interior of the cylinder. A hollow cavity is formed inside the cylinder, and the liquid inlet / outlet head communicates with the receiving cavity. The diameter of the receiving cavity is in the range of 15~17mm, and the length of the receiving cavity is greater than 120mm.

[0008] Furthermore, the movable plug is detachably connected to the front end of the push rod, one end of the movable plug is provided with a first internal thread, and the front end of the push rod is provided with a first external thread that mates with the first internal thread; the outer periphery of the movable plug is provided with a first annular groove, and a sealing ring is provided in the first annular groove.

[0009] Furthermore, the liquid inlet / outlet head is eccentrically positioned on the front end face of the cylinder, and the liquid inlet / outlet head is positioned above when the conveyor is positioned on the positioning structure; a locking connector is provided on the outer periphery of the liquid inlet / outlet head, a limit ring is provided on the inner side of the tail of the cylinder, and the push rod passes through the limit ring and connects to the movable plug.

[0010] Furthermore, the motor is mounted on the PCB board and is located at the bottom of the support plate. The support plate has a first mounting seat and a second mounting seat at its two ends respectively. One end of the positioning seat is connected to the first mounting seat. The two ends of the lead screw are rotatably mounted on the first mounting seat and the second mounting seat respectively. A transmission belt is wound around the output shaft end of the motor, and the other end of the transmission belt is wound around one end of the lead screw.

[0011] Furthermore, a first sensor and a second sensor are provided at both ends of one side of the support plate, and a sensing plate that works in conjunction with the first sensor and the second sensor is provided on one side of the movable seat; a pair of guide rails extending along a first direction are provided between the first mounting seat and the second mounting seat, and the movable seat is movably mounted on the guide rails via bearings; both ends of one of the guide rails are provided with limiting members, and the movable seat is located between the two limiting members, the position of the limiting members being adjustable along the first direction.

[0012] Furthermore, a sleeve is movably sleeved on the outer periphery of the front end of the push rod. The sleeve is adjustablely positioned on the first mounting base by means of an adjustment structure. The first mounting base is provided with a positioning groove for positioning the sleeve.

[0013] Furthermore, the positioning structure includes a positioning cavity disposed on the positioning seat, a first positioning hole disposed at one end of the positioning cavity and positioning the tail of the cylinder, and a limiting unit disposed at the other end of the positioning cavity. A coaxial clearance hole is disposed on one side of the first positioning hole. The clearance hole communicates with the first positioning hole, and the diameter of the clearance hole is smaller than the diameter of the first positioning hole, thereby forming a limiting step to limit the tail of the cylinder. The push rod passes through the clearance hole and extends into the cylinder to push the movable plug to move.

[0014] Furthermore, a notch is provided at the bottom center of the positioning cavity, and the limiting sensor is located at the notch; the limiting unit includes a limiting plate and a pair of limiting blocks abutting against both sides of the cylinder, the limiting plate is provided with a limiting groove, and the limiting blocks are provided with grooves on their opposite inner sides, the grooves are embedded with elastic elements, and the elastic elements are elastically clamped on both sides of the cylinder; the positioning cavity is provided with an avoidance cavity communicating with the positioning cavity on the side near the limiting unit.

[0015] Another object of the present invention is to provide a hot steam ablation device, which includes a housing and a liquid injection device as described above, the liquid injection device being disposed on the housing, the housing being provided with an installation groove, the position of the installation groove corresponding to the position of the positioning structure.

[0016] Compared with the prior art, the beneficial effects of the liquid injection device and hot steam ablation equipment of the present invention are as follows: (1) Realize electrical detection of the conveyor installation and eliminate the risk of accidental start: The positioning structure on the positioning seat is equipped with a limit sensor, which can perform real-time electrical detection on whether the conveyor is placed in place. This design overcomes the defect of existing technology that relies only on mechanical limit and lacks electrical confirmation. The control system can only start the injection action after receiving the position signal from the limit sensor, thereby preventing safety hazards such as push rod empty push, liquid leakage or movable plug deviation caused by the conveyor not being fully installed in place. (2) Ensure precise coaxiality between the push rod and the cylinder to improve the consistency and reliability of the injection: The push rod is set coaxially with the cylinder, and the diameter of the push rod is smaller than the diameter of the cylinder. This structure ensures that when the push rod extends into the cylinder to push the movable plug, it does not come into contact with or scrape the inner wall of the cylinder, so that the thrust is transmitted smoothly along the axis of the cylinder. This effectively avoids the movable plug jamming, seal ring wear or push rod bending deformation caused by the skewed torque, thus ensuring the repeatability of positioning accuracy and motion consistency of each injection. (3) Construct a force-displacement collaborative monitoring mechanism to realize intelligent overload protection and abnormal diagnosis: A pressure sensor is installed between the tail of the push rod and the moving seat. During the injection process, the sensor can monitor the magnitude of the axial thrust in real time, which together with the displacement stroke of the moving seat constitutes a dual criterion of force and displacement. On the one hand, when the thrust is detected to exceed the safety threshold (such as pipeline blockage or pushing to the hard limit), the system can immediately perform emergency stop or reverse to prevent damage to the moving plug, sealing ring or cylinder due to overpressure. On the other hand, if the moving seat moves normally but the pressure is abnormally low, the system can accurately determine that it is in an empty push or liquid exhaustion state, thereby alarming in time and greatly improving the safety and fault diagnosis capability of the equipment in clinical use. (4) Ensure precise injection of micro-volume liquid through automated precision drive: The motor drives the lead screw to move the moving seat and push rod back and forth along the first direction. This automated transmission mechanism can achieve high-precision linear displacement control of the push rod. Combined with the real-time feedback of the pressure sensor, the injection speed and stroke can be precisely adjusted to ensure that the single injection dose is accurate and controllable, thereby significantly improving the consistency and stability of the treatment effect. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the liquid injection device according to Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the liquid injection device according to Embodiment 1 of the present invention from another angle; Figure 3 This is a schematic diagram of the injection mechanism according to Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the positioning seat according to Embodiment 1 of the present invention; Figure 5 This is a structural schematic diagram of the positioning seat from another angle according to Embodiment 1 of the present invention; Figure 6 This is a schematic diagram of the structure of the limiting sensor according to Embodiment 1 of the present invention; Figure 7 This is a schematic diagram of the conveyor structure according to Embodiment 1 of the present invention; Figure 8 This is a cross-sectional structural schematic diagram of the conveyor in Embodiment 1 of the present invention; Figure 9 This is Embodiment 1 of the present invention. Figure 8 A schematic diagram of the structure at point D in the middle section; Figure 10 This is a schematic diagram of the structure of the cylinder according to Embodiment 1 of the present invention; Figure 11 This is a schematic diagram of the structure of the conveyor in Embodiment 1 of the present invention when the movable plug is pulled to the maximum size of the accommodating cavity; Figure 12 This is an exploded structural diagram of the conveyor of Embodiment 1 of the present invention; Figure 13 This is a schematic diagram of the structure of the hot steam ablation device according to Embodiment 2 of the present invention; The numbers in the diagram represent: Injection device-100; Hot steam ablation equipment-200, housing-201, mounting groove-202; Positioning seat-1, positioning structure-11, positioning cavity-111, first positioning hole-112, limiting unit-113, limiting plate-1131, limiting block-1132, groove-1133, limiting groove-1135, clearance hole-114, notch-115, clearance cavity-116, limiting sensor-12, sensing end-121, main body-122, metal spring-123, first fastener-13, mating protrusion-14; Conveyor-2, cylinder-21, hollow cavity-211, push rod-22, first external thread-221, movable plug-23, first internal thread-231, first annular groove-232, sealing ring-233, liquid inlet Protrusion-24, Second external thread-241, Slot-242, Limiting part-243, Inlet / outlet liquid channel-244, Inlet / outlet positioning section-245, Receiving cavity-25, Locking connector-26, Second internal thread-261, Buckle-262, Limiting ring-27; Pushing mechanism-3, Motor-31, Transmission belt-311, Lead screw-32, Moving seat-33, Sensing plate-331, Push rod-34, Sleeve-341, Waist-shaped hole-342, Pressure sensor-35, Support plate-36, First mounting seat-361, Positioning groove-3611, Mating groove-3612, Second mounting seat-362, Guide rail-363, Bearing-364, First sensor-365, Second sensor-366, Limiting part-367, PCB board-37. Detailed Implementation

[0018] Example 1: Please refer to Figures 1-12 This embodiment is a liquid injection device 100, which includes: Conveyor 2, which includes a cylinder 21 and a movable plug 23 movably disposed inside the cylinder 21, wherein the movable plug 23 and the inner wall of the front end of the cylinder 21 form a receiving cavity 25; Positioning seat 1, with positioning structure 11 of positioning conveyor 2 provided on positioning seat 1, and limit sensor 12 provided below positioning structure 11; The injection mechanism 3 includes a motor 31, a lead screw 32 driven by the motor 31, a movable seat 33 connected to the lead screw 32 and reciprocating along a first direction, and a push rod 34 horizontally connected to the movable seat 33. The first direction is the axial direction of the cylinder 21. The push rod 34 is coaxially arranged with the cylinder 21 and the outer diameter of the push rod 34 is smaller than the inner diameter of the cylinder 21. A pressure sensor 35 is provided between the tail of the push rod 34 and the movable seat 33. The front end of the push rod 34 acts on the movable plug 23.

[0019] The conveyor 2 also includes a liquid inlet / outlet head 24 disposed at the front end of the cylinder 21 and a push rod 22 extending from the rear end of the cylinder 21 into the interior of the cylinder 21. A hollow cavity 211 is formed inside the cylinder 21. The liquid inlet / outlet head 24 communicates with a receiving cavity 25. An inlet / outlet channel 244 is provided inside the liquid inlet / outlet head 24, and the receiving cavity 25 communicates with the inlet / outlet channel 244. One end of the cylinder 21 is integrally connected to the liquid inlet / outlet head 24, and the other end of the cylinder 21 is open. The push rod 22 extends into the cylinder 21 from the opening to drive the movable plug 23 to reciprocate, thereby allowing liquid to enter the receiving cavity 25 from the liquid inlet / outlet head 24, or allowing liquid in the receiving cavity 25 to be pumped out from the liquid inlet / outlet head 24. In this embodiment, the liquid is water. In other embodiments, the specific type of liquid can be adjusted according to actual conditions and is not limited here.

[0020] The movable plug 23 is detachably connected to the front end of the push rod 22. One end of the movable plug 23 has a first internal thread 231, and the front end of the push rod 22 has a first external thread 221 that mates with the first internal thread 231. The movable plug 23 and the push rod 22 are connected by a detachable thread, a design that offers several advantages: when the movable plug 23 wears out, only the movable plug 23 needs to be replaced, eliminating the need to scrap the entire assembly of the push rod 22 and the movable plug 23, thus reducing maintenance costs; the split design allows each component to be disassembled and cleaned independently, avoiding the risk of residual contaminants at the threaded connection points; each component can be sterilized independently, preventing cross-contamination; in actual operation, the push rod 22 is only used for liquid aspiration or auxiliary degassing. After the aspiration or degassing operation is completed, the push rod 22 can be unscrewed from the movable plug 23 and pulled out. The push rod 34 then directly pushes the movable plug 23 to move, achieving automated injection. The use of a motor 31 to drive the push rod 34 ensures precise movement. The pulled-out push rod 22 can be cleaned, disinfected, and reused, saving consumables.

[0021] The movable plug 23 has a first annular groove 232 on its outer periphery, and a sealing ring 233 is disposed within the first annular groove 232. The sealing ring 233 elastically abuts against the inner wall of the cylinder 21 to achieve dynamic sealing. This sealing structure maintains good sealing performance while ensuring low frictional resistance, avoiding jamming of the movable plug 23 during pushing and pulling due to excessive sealing, and also preventing liquid and gas leakage caused by insufficient sealing, thereby ensuring the accuracy of injection metering and smooth operation. In addition, the annular groove structure can stably accommodate and position the sealing ring 233, preventing it from shifting or twisting during reciprocating pushing and pulling, ensuring that the sealing ring is always tightly fitted against the inner wall of the cylinder 21, thereby obtaining a reliable and durable dynamic sealing effect, effectively preventing leakage of liquid or vapor in the receiving cavity 25.

[0022] The liquid inlet / outlet head 24 is eccentrically positioned on the front end face of the cylinder 21. When the delivery device 2 is positioned on the positioning structure 11, the liquid inlet / outlet head 24 is located at the top, facilitating the discharge of gas from the containment cavity 25. This design has several outstanding advantages: First, utilizing the physical property that gas density is less than liquid density, residual gas in the containment cavity 25 will naturally float to the highest point under buoyancy, and be preferentially and thoroughly discharged through the top-positioned liquid inlet / outlet head 24. This effectively avoids the risk of air embolism caused by gas being injected into the human body along with the liquid, ensuring treatment safety and absolute accuracy of the injection dosage. Precision; secondly, the top venting layout allows clinical operators to clearly observe the venting status of air bubbles before injection, and also facilitates uninterrupted connection of external tubing from above, avoiding tubing bends or interference with other components, thereby comprehensively improving the ease of operation, reliability, and clinical efficiency of the equipment; in addition, the eccentric structure, combined with the positioning installation design on the instrument, ensures that the liquid inlet / outlet head 24 always faces upwards, providing directional error prevention and ensuring that the venting position is accurately reached without deliberate adjustment each time it is loaded, avoiding the misinstallation or angle deviation problems that may be caused by the centrally symmetrical structure.

[0023] A locking connector 26 is fitted around the outer periphery of the liquid inlet / outlet head 24. One end of the locking connector 26 has a second internal thread 261, and the outer periphery of the liquid inlet / outlet head 24 has a second external thread 241 that mates with the second internal thread 261. The other end of the locking connector 26 has a latch 262, and the outer periphery of the liquid inlet / outlet head 24 has a groove 242 that mates with the latch 262. A limiting part 243 is provided on the outer periphery of the liquid inlet / outlet head 24 near the cylinder 21, and the limiting part 243 axially limits the locking connector 26. The locking connector 26 provides axial locking force through the second internal thread 261 and the second external thread 241, which, together with the snap fastener 262 and the slot 242, achieves quick positioning and anti-rotation. Simultaneously, a limiting part 243 located on the outer periphery of the liquid inlet / outlet head 24 near the cylinder 21 axially limits the locking connector 26. This complete design has multiple advantages: First, the limiting part 243 provides a clear screw-in endpoint for the locking connector 26 during thread tightening, preventing excessive tightening that could cause stripping or damage to the second external thread 241 or the second internal thread 261. It also avoids excessive compression of the sealing surface by the locking connector 26, which could lead to deformation and failure of the sealing ring. Thus, it effectively protects the long-term service life of the threaded pair and sealing structure while ensuring a secure connection. Second, the limiting part 243 ensures that the locking connector 26 is in a consistent axial position during each assembly, allowing the snap fastener 262 to... The locking part 243 precisely aligns with and reliably engages with the slot 242, preventing the buckle 262 from failing to enter the slot or from being insufficiently engaged due to deviations in the screwing depth, thus losing its anti-rotation function and improving the synergistic reliability of the dual locking mechanism. Third, in clinical operations, the limiting part 243 provides a clear tactile feedback and a limiting stop, allowing the operator to perceive that the locking connector 26 is tightened without visual inspection, reducing the risk of loose or overtight connections due to differences in operating experience. At the same time, the limiting part 243 also prevents the locking connector 26 from accidentally slipping off the front end of the liquid inlet / outlet head 24 during disassembly, preventing small parts from falling into the sterile area and causing contamination or loss. In addition, combined with the eccentric venting design and the detachable movable plug structure, the limiting part 243 ensures the consistency of the tubing interface orientation, keeping the external tubing in the predetermined position and preventing tubing twisting and pulling from affecting the venting effect or injection accuracy. In summary, this design comprehensively optimizes the reliability of interface connections and the human-computer interaction experience from four dimensions: overload protection, positioning consistency, operation feel, and anti-drop. It fully meets the stringent requirements of high-pressure medical scenarios for connection structures that are safe, durable, easy to use, and prevent misoperation.

[0024] A limiting ring 27 is provided on the inner side of the tail of the cylinder 21. The diameter of the push rod 22 is smaller than the inner diameter of the cylinder 21, and the diameter of the push rod 22 is smaller than the inner diameter of the limiting ring 27. The push rod 22 passes through the limiting ring 27 and connects to the movable plug 23. The limiting ring 27 can prevent the movable plug 23 from falling out of the cylinder 21 and prevent leakage. The limiting ring 27 is internally interference-fitted with the cylinder 21. Its core advantage lies in achieving three functions—fixation, sealing, and limiting—with a simple structure: First, it provides a stable and reliable fixation, firmly locking in place without the need for threads or adhesives, and can withstand repeated impacts from the movable plug 23 without shifting, ensuring a constant starting position for pulling and guaranteeing metering accuracy. Second, it enhances leak-proof performance; the interference-fit interface itself also acts as a seal, forming a double leak-proof barrier with the sealing ring 233 of the movable plug 23. Even if the sealing ring 233 ages and wears, it can effectively seal the tail channel of the cylinder 21, preventing leakage. Third, it facilitates assembly and maintenance, eliminating complex processes such as bonding, curing, or thread tightening. Furthermore, it can be pressed out and disassembled when necessary, facilitating internal cleaning or parts replacement, combining the efficiency of one-time assembly with maintainability. In summary, this design solves the problems of limiting, sealing, and impact resistance simultaneously with minimal cost and structural complexity. In other embodiments, the limiting ring 27 and the cylinder 21 can also be fixedly connected via threads.

[0025] In this embodiment, the diameter of the receiving cavity 25 ranges from 15 to 17 mm. In actual use, the single ablation volume is 0.4 mL, meaning the volume of liquid injected from the receiving cavity 25 in a single operation is 0.4 mL. Preferably, the diameter of the receiving cavity 25 is 16 mm, meaning that in... Figure 11In the diagram, the dimension of A is 16mm. When the movable stopper 23 moves 1mm, the corresponding volume change is: π×8²×1≈201mm³=0.201mL. Therefore, the liquid volume corresponding to each 1mm movement of the movable stopper 23 is approximately 0.2mL. Thus, a single ablation operation only requires the movable stopper 23 to move 2mm. This size design offers multiple practical advantages: First, the stroke and dosage have an integer correspondence, allowing for quick calculation and precise control by the operator or control system, whether manually injected according to the cylinder scale or driven by the device's motor, avoiding measurement deviations or misoperations caused by non-integer strokes. Second, the short 2mm stroke significantly shortens the injection time per session, reducing the uncertainty of the patient's tissue heating time and minimizing the impact of operator hand tremors on dosage accuracy, making each injection more stable and reliable. Third, the 15-17mm diameter range balances sealing and smoothness, ensuring sufficient contact area between the sealing ring 233 and the inner wall of the cylinder 21 for reliable sealing, while avoiding excessive frictional resistance due to an excessively large diameter, making the movable plug 23 responsive and free from jamming during the micro-movement stroke. In addition, this design optimizes clinical efficiency; the short stroke combined with the large-capacity cavity allows for the storage of multiple ablation solutions in a single aspiration, avoiding frequent refills, and is particularly suitable for multi-lesion surgeries. In summary, this size parameter is a precise engineering match derived from the clinical requirement of 0.4 mL per ablation volume, achieving an optimal balance between metrological accuracy, ease of operation, sealing reliability, and surgical efficiency.

[0026] In this embodiment, the length of the receiving cavity 25 is greater than 120mm, preferably 130mm. Figure 11The size of B is 130mm. Based on the above volume calculation, when each 1mm corresponds to a volume of 0.2mL, the volume of the receiving cavity 25 corresponding to a length of 130mm is 26mL. Among them, about 3mL of liquid is used to fill the catheter connected to the liquid inlet / outlet head 24 to ensure that the tubing is free of air bubbles, and about 2mL is reserved as an alarm reserve volume. When the liquid level drops to this threshold, the operator is prompted to replace or replenish the liquid in time. After removing the above about 5mL of liquid, the effective liquid is 21mL, which means that it can be ablated about 50 times. However, the maximum number of times a single-use prostate thermal steam ablation catheter can be used in clinical practice is 15 times. In special cases, if more than 15 ablations are required, a new ablation catheter and delivery device need to be replaced. The design capacity of this solution is about three times the actual clinical needs. This sufficient redundancy brings multiple safety advantages. This design offers multiple clinical and engineering advantages: First, the ample single-load capacity significantly reduces the frequency of fluid changes during surgery, with a single load sufficient for approximately 50 ablation procedures. For multi-lesion or multi-round surgeries, it avoids interruptions caused by frequent infusion changes or repeated fluid aspiration, significantly shortening the overall surgical time and improving treatment fluency. Second, the reserved 3mL catheter residue and 2mL alarm volume ensure the integrity and safety of the dosage output. The 3mL residue ensures the tubing remains full and air-free, preventing gas from being injected into the body with the fluid, while the 2mL alarm reserve serves as a safety margin, triggering an alert when the fluid level is nearly depleted to prevent... The stopper 23, when pushed to its limit, prevents dry injection or gas aspiration, providing the operator with ample buffer time for replacement. Furthermore, the large-volume design, combined with a short 2mm single-stroke advance distance, ensures that the fluid level in the cavity decreases extremely slowly during multiple injections. Minor changes in the fluid level have almost no impact on the static pressure and venting effect at the fluid inlet / outlet head 24, further guaranteeing consistent dosage with each injection. In addition, the combination of a 130mm cavity length and a 16mm diameter maintains a slender ratio while ensuring sufficient volume, facilitating handheld operation and compatibility with the instrument's positioning mechanism, avoiding the inconvenience of gripping or loading interference caused by excessively short or thick cavities. Overall, this parameter design, based on actual clinical needs, achieves a precise balance between operational efficiency, safety redundancy, dosage stability, and ergonomics, fully embodying the end-in-the-world engineering design philosophy.

[0027] In this embodiment, when the diameter of the receiving cavity 25 is 16mm, the length of the receiving cavity 25 is 130mm, and the length of the cylindrical body 21 is approximately 150mm, that is... Figure 8The dimension of C is approximately 150mm. The length of push rod 22 is approximately 155mm, meaning the tail of push rod 22 extends approximately 5mm beyond the cylinder 21. In other embodiments, the length of the receiving cavity 25 is 130±5mm, or other parameters are designed, such as 140mm, 150mm, etc. In this case, the lengths of cylinder 21 and push rod 22 can be adjusted according to the actual situation. Therefore, the lengths of receiving cavity 25, cylinder 21, and push rod 22 are set according to the actual situation and are not limited here.

[0028] The motor 31 is mounted on the PCB board 37 and is located at the bottom of the support plate 36. The support plate 36 has a first mounting seat 361 and a second mounting seat 362 at its two ends. One end of the positioning seat 1 is connected to the first mounting seat 361 via a first fastener 13. The positioning seat 1 conforms to the first mounting seat 361; specifically, the first mounting seat 361 has a mating groove 3612, and one end of the positioning seat 1 has a mating protrusion 14. The two ends of the lead screw 32 are rotatably mounted on the first mounting seat 361 and the second mounting seat 362, respectively. A transmission belt 311 is wound around the output shaft end of the motor 31, and the other end of the transmission belt 311 is wound around one end of the lead screw 32. When the motor 31 drives the transmission belt 311, it drives the lead screw 32, thereby moving the movable seat 33 along the first direction, causing the push rod 34 to push the movable plug 23, thus pushing out the receiving cavity 25.

[0029] A first sensor 365 and a second sensor 366 are provided at both ends of one side of the support plate 36. A sensing element 331, which works in conjunction with the first sensor 365 and the second sensor 366, is provided on the side of the movable seat 33 to detect the position of the movable seat 33. To ensure the stability of the movable seat 33's movement along the first direction, a pair of guide rails 363 extending along the first direction are provided between the first mounting base 361 and the second mounting base 362. The movable seat 33 is movably mounted on the guide rails 363 via bearings 364, and moves along the guide rails 363. Limiting members 367 are provided at both ends of one of the guide rails 363. The movable seat 33 is located between the two limiting members 367, and the two limiting members 367 limit the forward and backward position of the movable seat 33. Preferably, the position of the limiting members 367 along the first direction is adjustable, which can limit different movement ranges of the movable seat 33. The first sensor 365 and the second sensor 366, together with the sensing element 331, detect the extreme stroke position of the moving seat 33 in real time. Together with the adjustable limiters 367 at both ends, they form an electromechanical dual overtravel protection system, preventing damage to the moving seat 33 from impacts. Simultaneously, they provide a zero-point reference for the motor 31 to precisely control the displacement of the push rod 34. A pair of guide rails 363 and bearings 364 ensure stable linear movement of the moving seat 33 along the first direction, ensuring coaxiality between the push rod 34 and the cylinder 21, reducing sway and friction, and improving injection smoothness and accuracy. Furthermore, the adjustable position of the limiters 367 allows for flexible adaptation to different stroke requirements. Overall, these designs, from four aspects—position closed-loop monitoring, safety redundancy protection, motion guidance stability, and stroke adjustability—jointly ensure the high precision, high reliability, and clinical operational safety of the injection mechanism in automated injection.

[0030] The pressure sensor 35 installed between the tail of the push rod 34 and the moving seat 33 can detect the pressure when the push rod 34 pushes the movable plug 23, thus preventing excessive pressure from damaging the movable plug 23. The pressure sensor 35 monitors the axial thrust in real time, and together with the displacement detection of the first sensor 365 and the second sensor 366, it forms a dual force-displacement criterion: On the one hand, when the pressure exceeds the safety threshold, such as when the pipeline is blocked or pushed to the hard limit, the system can immediately stop or reverse to prevent the movable plug 23, the sealing ring 233, or the cylinder 21 from being damaged by overpressure, thus achieving physical overload protection; on the other hand, if the movable seat 33 moves according to the command but the pressure is abnormally low, it can be judged as empty push, such as when the liquid is exhausted or the movable plug is dislodged. If the pressure rises suddenly and the displacement stops, it is judged as a blockage, thus accurately diagnosing abnormalities and alarming, avoiding the risk of empty injection or high-pressure injection; in addition, the pressure feedback can also be used for closed-loop speed regulation of the motor 31, automatically decelerating at the end of the injection to prevent the single 0.4mL dose from overshooting due to inertia, ensuring smooth and accurate micro-injection, and ultimately ensuring the safety of clinical operation and the protection of patient tissues from high pressure damage from the mechanical source.

[0031] A sleeve 341 is movably fitted around the front end of the push rod 34. The sleeve 341 is adjustable in position on the first mounting base 361 via an adjustment structure. The first mounting base 361 has a positioning groove 3611 for positioning the sleeve 341. Specifically, the adjustment structure includes a second positioning hole on the first mounting base 361, a vertically extending oblong hole 342 on the sleeve 341, and a second fastener passing through both the second positioning hole and the oblong hole 342. The position of the sleeve 341 can be adjusted vertically to ensure that the push rod 34 is coaxial with the cylinder 21, thereby ensuring the accuracy and stability of the push rod 34 during push. Through the engagement of the waist-shaped hole 342 with the second fastener, the sleeve 341 can be easily adjusted up and down to ensure that the push rod 34 and the cylinder 21 are precisely coaxial, thereby eliminating the adverse effects of eccentric torque on the movable plug 23 and the sealing ring 233, ensuring that the thrust is smoothly transmitted along the axial direction, improving the injection accuracy, sealing durability and long-term repeatable positioning reliability, and the adjustment structure is simple, requires no special tools, and is easy to assemble, calibrate and maintain.

[0032] The positioning structure 11 includes a positioning cavity 111 disposed on the positioning seat 1, a first positioning hole 112 disposed at one end of the positioning cavity 111 and at the tail of the positioning cylinder 21, and a limiting unit 113 disposed at the other end of the positioning cavity 111. A coaxial clearance hole 114 is disposed on one side of the first positioning hole 112, the clearance hole 114 communicating with the first positioning hole 112, and the diameter of the clearance hole 114 being smaller than the diameter of the first positioning hole 112, thereby forming a limiting step to limit the tail of the cylinder 21. The push rod 34 passes through the clearance hole 114 and extends into the cylinder 21 to push the movable plug 23 to move. The limiting step formed by the first positioning hole 112 and the clearance hole 114 provides a fixed axial reference for the tail of the cylinder 21, ensuring consistent loading position and guaranteeing measurement accuracy. The clearance hole 114 also provides proximal guide support for the slender push rod 34, allowing it to automatically maintain coaxiality with the cylinder 21, avoiding misalignment that could cause uneven wear of the movable plug 23, deformation of the sealing ring 233, or deflection of the push rod, ensuring smooth axial transmission of thrust and reducing frictional resistance. The overall structure is simple and integrated, with the first positioning hole 112, clearance hole 114, and limiting step designed as a single unit, which simplifies assembly and allows the conveyor 2 to be positioned immediately upon insertion and easy to pick up and drop. It ensures consistent injection accuracy and long-term use from three aspects: unified reference, coaxial guidance, and structural reliability.

[0033] The limit sensor 12 is used to detect whether the conveyor 2 is in place. A notch 115 is provided at the bottom center of the positioning cavity 111, and the limit sensor 12 is located at the notch 115. Specifically, the sensing end 121 of the limit sensor 12 extends into the notch 115 to contact the outer periphery of the cylinder 21. The main body 122 of the limit sensor 12 is installed below the positioning cavity 111, and the sensing end 121 and the main body 122 are connected by a metal spring 123. The limit sensor 12, through the notch 115, allows the sensing end 121 to contact the outer periphery of the cylinder 21. Combined with the elastic floating of the metal spring 123, it compensates for tolerances and buffers against damage, achieving reliable placement detection. The sensor main body 122 is hidden below the positioning cavity 111, not interfering with the placement and removal of the conveyor 2, and has a compact structure. The electrical signal of the limit sensor 12, together with the mechanical limit of the first positioning hole 112 and the limit unit 113, constitutes a dual placement verification, ensuring that injection can only be initiated when the device is actually in place, thus guaranteeing injection safety and reliability from the source.

[0034] The limiting unit 113 includes a limiting plate 1131 for limiting the liquid inlet / outlet head 24 and a pair of limiting blocks 1132 abutting against both sides of the cylinder 21. At this time, the liquid inlet / outlet head 24 is positioned at the top to facilitate the discharge of gas from the cylinder 21. The front end face of the cylinder 21 and one side of the limiting portion 243 are respectively located on both sides of the limiting plate 1131. The limiting plate 1131 is provided with a limiting groove 1135. The inlet / outlet positioning section 245 on the liquid inlet / outlet head 24 is engaged in the limiting groove 1135 of the limiting plate 1131. The limiting portion 243 and the front end face of the cylinder 21 abut against both sides of the limiting plate 1131. The groove width at the lower end of the limiting groove 1135 is contoured to the outer diameter of the inlet / outlet positioning section 245, while the groove width at the upper end of the limiting groove 1135 is smaller than the outer diameter of the inlet / outlet positioning section 245. The limiting plate 1131 is elastic. The elastic limiting groove 1135 of the limiting plate 1131, through the structure of the lower end conforming and the upper end narrowing, realizes the rapid guidance and elastic clamping to prevent the liquid inlet / outlet head positioning section 245 from falling off. It works in conjunction with the eccentric design to ensure that the liquid inlet / outlet head 24 is always facing upward. At the same time, the elastic clamping can adaptively eliminate tolerances and provide a clear and precise feel. Thus, it provides comprehensive protection in four dimensions: loading convenience, orientation error prevention, positioning accuracy, and operational reliability.

[0035] The limiting block 1132 has a groove 1133 on its inner side. An elastic element is embedded in the groove 1133. The elastic element is elastically clamped on both sides of the cylinder 21. The elastic element applies elastic clamping to both sides of the cylinder 21 through the groove 1133, adaptively compensating for manufacturing tolerances and wear, and providing a stable clamping force. At the same time, it flexibly buffers the impact of injection, protects the surface of the cylinder, reduces the picking and placing force, and works with the limiting plate 1131 to form a two-way flexible positioning in the axial and radial directions, ensuring repeatability and avoiding over-constraint.

[0036] The positioning cavity 111 has a clearance cavity 116 connected to it on the side near the limiting unit 113, so that the operator's hand can be placed down or taken out of the conveyor 2 from here. The clearance cavity 116 provides the necessary finger operating space for picking up and putting down the conveyor 2, so that the actions of pinching the cylinder 21, rotating and pressing down, and lifting in the opposite direction can be smooth and unobstructed, avoiding interference between the fingers and the side wall of the positioning cavity 111. At the same time, it guides the operator to follow the correct assembly sequence, improving the convenience of picking up and putting down, the smoothness of the action, and the prevention of misoperation.

[0037] When using the liquid injection device 100 provided in this solution, the operator first connects the first external thread 221 at the front end of the push rod 22 with the first internal thread 231 of the movable plug 23, fixing the push rod 22 and the movable plug 23 as one unit. Then, the operator pulls the push rod 22 backward, driving the movable plug 23 to move backward along the inner wall of the cylinder 21, drawing the liquid into the receiving cavity 25 through the inlet / outlet channel 244 of the liquid inlet / outlet head 24. After the liquid is drawn in, the eccentrically positioned liquid inlet / outlet head 24 is placed horizontally upward. Since the gas density is less than that of the liquid, the residual gas naturally floats to the top. The operator gently pushes the push rod 22 to move the movable plug 23 forward, allowing the gas to be preferentially discharged through the liquid inlet / outlet head 24 until it reaches the inlet / outlet channel. Continuous liquid flow at point 244 ensures no air bubbles in the pipeline; after venting, rotate push rod 22 to disengage it from movable plug 23 and pull it out. The pulled-out push rod 22 can be reused after cleaning and disinfection. At this time, movable plug 23 remains independently inside cylinder 21; next, the operator inserts their fingers into the clearance chambers 116 on both sides of positioning chamber 111, pinches the front part of cylinder 21, and first inserts the tail of cylinder 21 obliquely into the first positioning hole 112 on positioning seat 1 until the tail end face of cylinder 21 abuts against the limiting step formed by clearance hole 114 and first positioning hole 112. Then, using the tail as a fulcrum, the front end is rotated downward and pressed so that the inlet / outlet positioning section 245 of liquid inlet / outlet head 24 is engaged with elastic limiting plate 113. In the limiting groove 1135 of cylinder 21 (with lower end contour guide and upper end constricted elastic clamping), the elastic elements embedded in the grooves 1133 on both sides of cylinder 21 apply elastic clamping force to it, adaptively compensating for tolerances and buffering vibrations, until the sensing end 121 of the limit sensor 12 is triggered by contact with the outer periphery of cylinder 21. The position deviation is compensated by the elastic floating of the metal spring 123, and a position signal is sent to the control system, forming a double position verification with the mechanical limit. After the control system confirms the position, the starter motor 31 drives the lead screw 32 to rotate through the transmission belt 311, which drives the moving seat 33 to move forward along the guide rail 363, so that the push rod 34 passes through the clearance hole 114 and extends into the tail of cylinder 21 and pushes the movable plug 23. During this process, the sensing plate 331 on the side of the moving seat 33, together with the first sensor 365 and the second sensor 366, detects the displacement in real time, while the pressure sensor 35 at the tail of the push rod 34 synchronously monitors the axial thrust. The two constitute a force-displacement dual criterion. When the pressure exceeds the threshold, an emergency stop and reversal are implemented to achieve overload protection. When the displacement is normal but the pressure is abnormally low, an alarm is triggered to indicate an empty push or liquid exhaustion. When the pressure rises sharply and the displacement stops, an alarm is triggered to indicate blockage. At the same time, the pressure feedback is used for the closed-loop speed regulation of the motor 31 to achieve automatic deceleration at the end of the push to prevent over-rushing. The control system accurately controls the moving seat 33 to advance 2mm according to the conversion relationship of 0.2mL per millimeter for a diameter of 16mm in the receiving cavity 25.4 mL of liquid is dispensed through the liquid inlet / outlet head 24. A single 26 mL load (minus 3 mL for tubing filling and 2 mL for alarm retention, leaving 21 mL effective) can support approximately 50 dispensing cycles. After a set number of dispensing cycles, such as 20, the motor 31 reverses, causing the push rod 34 to retract. The operator's fingers, through the clearance cavity 116, first lift the front end of the cylinder 21 upwards, disengaging the inlet / outlet head positioning section 245 from the limiting groove 1135, and then diagonally pull out the tail section, completing the removal of the conveyor 2.

[0038] Example 2: Please refer to Figure 13 This embodiment provides a hot steam ablation device 200, which includes a housing 201 and a liquid injection device 100 as described in Embodiment 1. The liquid injection device 100 is disposed on the housing 201, and the housing 201 is provided with an installation groove 202. The position of the installation groove 202 corresponds to the position of the positioning structure 11, so as to position the conveyor 2 from the installation groove 202 to the positioning structure 11.

[0039] The above descriptions are merely some embodiments of the present invention. Those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A liquid injection device, characterized in that, It includes: The conveyor (2) includes a cylinder (21) and a movable plug (23) movably disposed inside the cylinder (21), wherein the movable plug (23) and the inner wall of the front end of the cylinder (21) form a receiving cavity (25). Positioning seat (1), the positioning seat (1) is provided with a positioning structure (11) for positioning the conveyor (2), and a limit sensor (12) is provided below the positioning structure (11). The injection mechanism (3) includes a motor (31), a lead screw (32) driven by the motor (31), a movable seat (33) connected to the lead screw (32) and reciprocating along a first direction, and a push rod (34) horizontally connected to the movable seat (33). The first direction is the axial direction of the cylinder (21). The push rod (34) is coaxially arranged with the cylinder (21) and the outer diameter of the push rod (34) is smaller than the inner diameter of the cylinder (21). A pressure sensor (35) is provided between the tail of the push rod (34) and the movable seat (33). The front end of the push rod (34) acts on the movable plug (23).

2. The liquid injection device as described in claim 1, characterized in that: The conveyor (2) further includes a liquid inlet / outlet head (24) disposed at the front end of the cylinder (21) and a push rod (22) extending from the tail end of the cylinder (21) into the interior of the cylinder (21). A hollow cavity (211) is formed inside the cylinder (21). The liquid inlet / outlet head (24) is connected to the receiving cavity (25). The diameter of the receiving cavity (25) is in the range of 15~17mm, and the length of the receiving cavity (25) is greater than 120mm.

3. The liquid injection device as described in claim 2, characterized in that: The movable plug (23) is detachably connected to the front end of the push rod (22). One end of the movable plug (23) is provided with a first internal thread (231), and the front end of the push rod (22) is provided with a first external thread (221) that mates with the first internal thread (231). The outer periphery of the movable plug (23) is provided with a first annular groove (232), and a sealing ring (233) is provided in the first annular groove (232).

4. The liquid injection device as described in claim 2, characterized in that: The liquid inlet / outlet head (24) is eccentrically positioned on the front end face of the cylinder (21). When the conveyor (2) is positioned on the positioning structure (11), the liquid inlet / outlet head (24) is located above it. A locking connector (26) is provided on the outer periphery of the liquid inlet / outlet head (24). A limit ring (27) is provided on the inner side of the tail of the cylinder (21). The push rod (22) passes through the limit ring (27) and connects to the movable plug (23).

5. The liquid injection device as described in claim 1, characterized in that: The motor (31) is mounted on the PCB board (37) and the motor (31) is located at the bottom of the support plate (36). The support plate (36) has a first mounting seat (361) and a second mounting seat (362) at both ends. One end of the positioning seat (1) is connected to the first mounting seat (361). The two ends of the lead screw (32) are rotatably mounted on the first mounting seat (361) and the second mounting seat (362) respectively. The output shaft end of the motor (31) is wound with a transmission belt (311), and the other end of the transmission belt (311) is wound around one end of the lead screw (32).

6. The liquid injection device as described in claim 5, characterized in that: The support plate (36) has a first sensor (365) and a second sensor (366) at both ends on one side. The movable seat (33) has a sensing plate (331) on one side that works in conjunction with the first sensor (365) and the second sensor (366). A pair of guide rails (363) extending in a first direction are provided between the first mounting seat (361) and the second mounting seat (362). The movable seat (33) is movably mounted on the guide rails (363) via bearings (364). Each end of one of the guide rails (363) is provided with a limiting member (367). The movable seat (33) is located between the two limiting members (367). The position of the limiting member (367) is adjustable in the first direction.

7. The liquid injection device as described in claim 5, characterized in that: The front end of the push rod (34) is movably fitted with a sleeve (341). The sleeve (341) is adjustablely positioned on the first mounting base (361) by means of an adjustment structure. The first mounting base (361) is provided with a positioning groove (3611) for positioning the sleeve (341).

8. The liquid injection device as described in claim 1, characterized in that: The positioning structure (11) includes a positioning cavity (111) disposed on the positioning seat (1), a first positioning hole (112) disposed at one end of the positioning cavity (111) and positioning the tail of the cylinder (21), and a limiting unit (113) disposed at the other end of the positioning cavity (111). A coaxial clearance hole (114) is provided on one side of the first positioning hole (112). The clearance hole (114) communicates with the first positioning hole (112), and the diameter of the clearance hole (114) is smaller than the diameter of the first positioning hole (112), thereby forming a limiting step to limit the tail of the cylinder (21). The push rod (34) passes through the clearance hole (114) and extends into the cylinder (21) to push the movable plug (23) to move.

9. The liquid injection device as described in claim 8, characterized in that: The positioning cavity (111) has a notch (115) at its bottom center, and the limiting sensor (12) is located at the notch (115). The limiting unit (113) includes a limiting plate (1131) and a pair of limiting blocks (1132) abutting against both sides of the cylinder (21). The limiting plate (1131) has a limiting groove (1135), and the limiting blocks (1132) have grooves (1133) on their opposite inner sides. An elastic element is embedded in the groove (1133), and the elastic element is elastically clamped on both sides of the cylinder (21). The positioning cavity (111) has an avoidance cavity (116) communicating with the positioning cavity (111) on the side near the limiting unit (113).

10. A hot steam ablation device, characterized in that: It includes a housing (201) and a liquid injection device (100) as described in any one of claims 1 to 9, wherein the liquid injection device (100) is disposed on the housing (201), and the housing (201) is provided with a mounting groove (202), the position of which corresponds to the position of the positioning structure (11).

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