Anti-reflux urinary catheter device

Abstract

The utility model relates to a kind of anti-reflux urinary catheter device, including urinary catheter and the anti-backflow valve assembly and sealing ring of its inner cavity, anti-backflow valve assembly includes the retaining rod extending along urinary catheter axial direction, and valve piece is slidably sleeved on it;Valve piece proximal end surface is provided with inclined sealing surface, to form sealing fit with the inner side corresponding slope of sealing ring;Retaining rod is provided with the variable stiffness spring around, and proximal end is abutted on the bottom surface of valve piece far end.This utility model's urinary catheter device is combined with the nonlinear resilience of spring and the impact damping effect of limiting flange, so that valve piece can be gradually reset along axial direction, to realize dynamic sealing balance in the case of pressure mutation.This design is particularly suitable for coping with the common bladder pressure sudden rise in neurogenic bladder, ensure that the device can still effectively maintain sealing state when pressure increases suddenly, reduce the risk of urine reflux.

Description

Technical Field

[0001] This utility model relates to the field of medical device technology, and in particular to a portable anti-backflow catheterization device. Background Technology

[0002] Neurogenic bladder (NB) is a group of diseases caused by neurological disorders leading to bladder and / or urethral dysfunction (i.e., storage and / or voiding dysfunction), resulting in a series of lower urinary tract symptoms and complications. NB can be caused by neurological diseases such as spinal cord injury (SCI), multiple sclerosis, Parkinson's disease, cerebral palsy, and stroke. Its main pathological feature is detrusor-sphincter dyssynergia (DSD), where abnormal detrusor contraction and uncoordinated closure of the urethral sphincter occur simultaneously, causing a sudden and rapid increase in intravesical pressure beyond the physiological range. This high-pressure state is dynamically fluctuating, often accompanied by frequent, disordered pressure spikes, which can easily lead to bladder wall damage, urine reflux, and upper urinary tract dilation, ultimately resulting in hydronephrosis and renal failure.

[0003] Existing anti-reflux designs for conventional urinary catheters are primarily designed for the low-pressure steady-state environment of the bladder. Their check valve spring stiffness and sealing structure are typically only adapted to conventional pressure thresholds. When applied to neurogenic bladder, three main drawbacks exist: First, traditional spring valves exhibit delayed response under high-pressure spikes. When instantaneous pressure exceeds the spring preload, the valve body opens rapidly but cannot reset in time, leading to backflow protection failure. Second, rigid valve seats and sealing surfaces are prone to micro-deformation under repeated high-pressure impacts, causing chronic leakage. Third, the catheter lumen lacks anti-collapse design; urethral bending or external compression can easily interrupt drainage, further exacerbating intrabladder pressure buildup. Furthermore, NB patients often have bladder wall fibrosis and increased urinary sediment, making the straight-through flow path of conventional catheters susceptible to blockage by impurities, exacerbating the conflict between drainage efficiency and pressure control. These issues make existing catheters insufficient to meet the safety requirements of long-term management of NB patients, necessitating a dedicated anti-reflux device that can dynamically adapt to high-pressure fluctuations, suppress backflow, and ensure drainage reliability.

[0004] CN211659034U discloses a valved anti-backflow urinary catheter, which has a one-way valve structure on the catheter body. When urine flows out, the one-way valve opens automatically, and when urine flows back, the opening element closes the channel for urine backflow, thus preventing urine backflow.

[0005] However, this technical solution has significant shortcomings in addressing the specific high-pressure dynamic environment of neurogenic bladder. First, the elastic stiffness of the flow channel opening component is based on conventional pressure design and cannot adapt to instantaneous high-pressure spikes. Under extreme pressure, the valve core may fail to reset in time due to inertial lag, leading to backflow protection failure. Second, the planar closed structure of the one-way valve is prone to micro-deformation under high-pressure impact, and long-term pressure fluctuations may cause fatigue of the elastic valve, resulting in chronic leakage. In addition, urinary sediments often present in patients with neurogenic bladder tend to accumulate at the valve hinge, and this solution lacks a drainage or self-cleaning structure. Long-term use may result in impurities clogging the seal and affecting its reliability.

[0006] Furthermore, on the one hand, there are differences in understanding among those skilled in the art; on the other hand, the applicant studied a large number of documents and patents when making this utility model, but due to space limitations, not all details and contents were listed in detail. However, this does not mean that this utility model does not have the features of these prior art. On the contrary, this utility model has all the features of the prior art, and the applicant reserves the right to add relevant prior art to the background art. Utility Model Content

[0007] In view of the shortcomings of the prior art, this application proposes an anti-backflow catheterization device, which aims to solve one or more technical problems in the prior art.

[0008] This utility model relates to an anti-backflow catheterization device, which includes a catheter and an anti-backflow valve assembly and a sealing ring disposed in its inner cavity. The anti-backflow valve assembly includes a retaining rod extending axially along the catheter, on which a valve is slidably sleeved. The proximal end face of the valve is provided with an inclined sealing surface to form a sealing fit with the corresponding inclined surface on the inner side of the sealing ring. A variable stiffness spring is arranged around the retaining rod, with its proximal end abutting against the bottom surface of the distal end of the valve. When the bladder pressure increases, the valve is pushed by the urine force to overcome the resistance of the variable stiffness spring and slides distally to form a flow channel between the inclined sealing surface and the sealing ring. When the pressure drops, the variable stiffness spring drives the valve to reset with a nonlinear rebound force, and achieves gradual closure by colliding with the limiting flange radially bulging at the proximal end of the retaining rod.

[0009] The inclined sealing surface and the inclined surface of the sealing ring form a progressive contact seal in the closed state, effectively improving the interface fit and significantly reducing the risk of minor leakage. During a sudden increase in neurogenic bladder pressure, the valve is driven to slide distally by the force of urine. The variable stiffness spring, through its tapering helical diameter, generates increasing compressive stiffness. In the low-pressure stage, low stiffness allows the valve to quickly open the flow channel; during the pressure peak stage, high stiffness limits the valve's displacement. When the pressure drops, the spring, based on the synergistic effect of nonlinear rebound force and the collision damping of the limiting flange, causes the valve to gradually return to its axial position along the variable diameter section, achieving dynamic sealing balance under sudden pressure changes. Furthermore, the collision contact mechanism between the limiting flange at the end of the retaining rod and the valve further slows the closing speed through energy dissipation from mechanical collision, achieving a smooth transition from partial contact to complete sealing, effectively eliminating the repeated opening and closing phenomenon caused by pressure fluctuations during the closure process of traditional valves.

[0010] According to a preferred embodiment, the distal end of the check valve assembly is provided with a base, and the distal end of the variable stiffness spring abuts against the proximal end face of the base. The base provides stable support to the distal end of the spring, ensuring that the force transmission path always extends axially along the catheter during spring compression, thus avoiding the risk of misalignment of the sealing surface caused by lateral displacement.

[0011] According to a preferred embodiment, the inner wall of the catheter is provided with an annular groove, and the base is fixed to the annular groove by a plurality of radially peripheral support arms, so that a gap for urine to pass through can be formed between the base and the inner wall of the catheter. The support arms are evenly distributed circumferentially between the base and the inner wall of the catheter, forming a stable radial support network, which not only ensures that the base remains in a fixed position in the axial direction of the catheter, but also creates a continuous flow channel around the base through the gaps between the support arms, effectively reducing the resistance to urine flow.

[0012] According to a preferred embodiment, the end of the support arm forms a barb structure bent in the direction of the catheter lumen axis. The inner wall of the annular groove is provided with a stepped locking groove that matches the barb. When the support arm is inserted into the annular groove, the barb and the stepped locking groove form a bidirectional self-locking mechanism, restricting axial and radial displacement of the base. The bending direction of the barb end forms an acute angle with the catheter axis. During the insertion of the support arm into the annular groove, the barb contacts the inclined surface of the locking groove, generating radial elastic deformation until it is fully engaged in the locking groove and returns to its original shape, forming a circumferentially uniformly distributed mechanical self-locking node. The bidirectional self-locking mechanism restricts axial movement of the base through the perpendicular engagement of the barb and the stepped surface of the locking groove. Simultaneously, the curved surface fit between the sidewall of the barb and the inner wall of the locking groove effectively suppresses radial displacement, eliminating the risk of loosening caused by single-point stress concentration in traditional fixing methods. During dynamic catheterization, this structure can withstand the reverse thrust generated by spring compression and resist vibration displacement caused by urine impact, ensuring precise alignment of the valve and the sealing ring.

[0013] According to a preferred embodiment, the urinary catheter is divided into three regions along its axial direction: proximal, mid-section, and distal. A check valve assembly is located in the mid-section region. The sealing ring serves as a transition structure between the proximal and mid-sections, while the base serves as a transition structure between the mid-section and distal section. The sealing ring, as the transition interface between the proximal and mid-sections, naturally connects its annular contour with the inner wall of the catheter, ensuring a smooth transition in the proximal lumen while forming the first-level sealing reference surface of the check valve assembly, effectively preventing localized stagnation caused by proximal urine bypassing. The base, as the support hub between the mid-section and distal section, forms a mechanical coupling with the catheter wall through its circumferentially distributed support arms. This maintains the axial positioning accuracy of the check valve assembly while constructing an annular channel for distal urine flow, reducing flow resistance.

[0014] According to a preferred embodiment, the proximal region of the catheter has a tapering flow channel with an inlet in the shape of a flared funnel, forming a cross-section that gradually narrows from proximal to distal. This reduces turbulent flow resistance and guides the urine to converge towards the catheter's axis. The flared funnel extends into the catheter lumen with a naturally transitioning curved shape. When bladder pressure fluctuates, it rapidly captures the urine flow by increasing the inlet cross-sectional area, while the gradient change in the cross-sectional area of ​​the tapering flow channel guides the fluid to converge orderly towards the central region. This flow channel configuration allows the urine to form a stable laminar flow state before entering the mid-section check valve assembly, reducing flow energy loss and enhancing the directional driving force for subsequent valve opening through fluid aggregation.

[0015] According to a preferred embodiment, a vortex generator is disposed inside the constricting channel to create a vortex flow of urine using centrifugal force. The vortex generator includes several spiral guide vanes circumferentially distributed on the inner wall of the constricting channel. The height of the spiral guide vanes gradually decreases axially from the proximal end to the distal end to avoid pressure fluctuations caused by abrupt changes in the flow channel. The circumferentially uniformly distributed spiral guide vanes form a continuous centrifugal acceleration channel through their gradually decreasing height, causing the fluid to gradually transform from a proximal diffusion state to a laminar vortex flow around the lumen axis. Furthermore, the gradual decrease in the height of the spiral guide vanes matches the narrowing trend of the constricting channel, causing the vortex intensity to gradually increase axially, avoiding local pressure oscillations caused by traditional abrupt flow guidance structures, and maintaining a smooth transition of fluid pressure during bladder emptying.

[0016] According to a preferred embodiment, the distal section of the catheter is fixedly provided with a drainage channel within the catheter lumen through integral molding, shape interlocking, welding, or bonding. A skeleton is provided between the drainage channel and the inner wall of the catheter, wherein the skeleton is configured as a ring-shaped wire mesh to wrap around the drainage channel. The ring-shaped wire mesh skeleton wraps the drainage channel with a three-dimensional woven structure. Its geometric characteristics of uniformly distributed mesh holes provide circumferential elastic support for the drainage channel and enhance its compressive strength through the stress dispersion effect of the wire intersections, preventing lumen collapse caused by external pressure. The skeleton and the inner wall of the catheter are mechanically coupled through integral molding or bonding processes, ensuring that the drainage channel maintains axial alignment during dynamic catheterization, avoiding flow channel displacement or blockage caused by tube bending.

[0017] According to a preferred embodiment, the inner wall of the drainage channel is provided with several strip-shaped depressions extending along the direction of urine discharge. The cross-section of each depression is parabolic, with its maximum depth located in the central axis region of the bottom wall, and the depth smoothly decreasing towards the periphery until it is flush with the inner wall of the drainage channel. The strip-shaped depressions extend axially along the drainage channel to form a continuous guide channel structure. The geometric characteristics of the parabolic cross-section create a low-resistance mainstream pathway in the central region of the depression, guiding the core flow of urine to move at high speed along the axis, while the gently transitioning curved boundaries on both sides promote the formation of a laminar shear flow in the outer liquid. This velocity gradient distribution effectively suppresses stagnant areas at the contact surface between urine and the tube wall, reducing the adhesion probability of deposits such as proteins and crystals through shearing action, thereby reducing bacterial biofilm formation.

[0018] According to a preferred embodiment, the variable stiffness spring is a conical helical spring with a helical diameter that increases from the proximal end to the distal end. The distal, larger diameter end is welded and fixed to the end face of the base, while the proximal, smaller diameter end elastically abuts against the distal bottom surface of the valve. When the valve slides, the conical helical spring generates a nonlinear stiffness response through the diameter difference. The gradient change in the helical diameter of the conical spring causes it to exhibit a progressive stiffness enhancement characteristic during compression. When bladder pressure acts on the valve, the initial low stiffness of the proximal, smaller diameter end allows the valve to respond quickly and form a flow path, while the progressively increasing stiffness of the distal, larger diameter end suppresses excessive valve displacement through enhanced elastic resistance, ensuring that the sealing surface maintains a controllable gap opening under high pressure. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of a preferred urinary catheterization device according to this utility model;

[0020] Figure 2 This is a schematic diagram of the internal structure of the proximal segment of a preferred catheterization device of this utility model from a first-view perspective.

[0021] Figure 3 This is a schematic diagram of the internal structure of the proximal segment of a preferred catheterization device of this utility model from a second perspective.

[0022] Figure 4 This is a schematic diagram of the internal structure of the middle section of the catheter of a preferred catheterization device of this utility model from a first-view perspective;

[0023] Figure 5 This is a schematic diagram of the internal structure of the middle section of the catheter of a preferred catheterization device of this utility model from a second perspective.

[0024] Figure 6 This is a schematic diagram of the internal structure of the distal section of the catheter in a preferred catheterization device of this utility model.

[0025] List of reference numerals

[0026] 100: Proximal segment; 110: Gradual narrowing flow channel; 111: Trumpet-shaped flare; 120: Swirl generator; 121: Spiral guide vane; 200: Mid-section; 210: Check valve assembly; 211: Base; 215: Support arm; 216: Annular groove; 212: Holding rod; 217: Limiting flange; 213: Variable stiffness spring; 214: Valve; 250: Sealing ring; 300: Distal segment; 310: Skeleton; 320: Drainage channel; 321: Recess; 400: Urinary catheter. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the accompanying drawings.

[0028] Position definition: When the urinary catheter 400 is inserted into place, the part of its end remaining in the bladder cavity is called the proximal end, and the part extending outside the body is called the distal end.

[0029] This embodiment relates to an anti-backflow catheterization device, such as... Figure 1As shown, the device mainly includes a urinary catheter 400, which can be a clinically common double-lumen urinary catheter 400. It is a slender tubular structure made of medical-grade silicone material, with the proximal end being the inlet for insertion into the bladder and the distal end being the outlet for urine. The lumen of the urinary catheter 400 is divided axially into three continuous regions: a proximal segment 100, a mid-segment 200, and a distal segment 300. The proximal segment 100 employs a gradually changing cross-section design to optimize fluid dynamics, ensuring a smooth transition in urine flow velocity and reducing turbulent resistance. The mid-segment 200 integrates a check valve assembly 210 to achieve unidirectional urine flow guidance, effectively preventing backflow. The distal segment 300 serves as the main channel for urine discharge; its lumen is reinforced with an embedded skeleton 310 to enhance the catheter 400's resistance to bending while maintaining shape stability, ensuring unobstructed urine flow during long-term use. Preferably, the length ratio of the proximal 100mm, mid-section 200mm, and distal 300mm can be flexibly adjusted according to clinical needs. For example, a 1:1:3 ratio is suitable for short-distance catheterization scenarios requiring enhanced proximal 100mm fluid guidance, a 1:2:5 ratio is suitable for cases requiring extended mid-section 200mm to accommodate complex anti-backflow structures, while a 2:1:4 ratio prioritizes the long-term indwelling requirement for distal 300mm drainage stability. All ratio designs must balance hydrodynamic performance and structural strength, with the distal 300mm typically occupying the largest proportion to accommodate urethral anatomy differences among patients.

[0030] like Figure 4 , Figure 5 As shown, a check valve assembly 210 is fixedly installed along the axial centerline of the inner cavity of the middle section 200 of the catheter 400. This assembly consists of a retaining rod 212, a valve element 214, a variable stiffness spring 213, a base 211, and a sealing ring 250, forming a functional whole. The base 211 serves as the distal fixing base of the assembly and is rigidly anchored to the inner wall of the catheter 400 through a mechanical connection. The sealing ring 250 serves as the proximal sealing interface and forms a transition connection with the proximal edge of the inner cavity of the middle section 200. The retaining rod 212, the valve element 214, and the variable stiffness spring 213 are distributed along the axial space between the base 211 and the sealing ring 250, forming a dynamically opening and closing anti-backflow structure.

[0031] like Figure 4 , Figure 5 As shown, the retaining rod 212 is made of rigid metal material, and its body extends along the axis of the catheter 400, with its length matching the middle section 200 region. The proximal end of the rod body is provided with a radially bulging limiting flange 217, which is a thin-walled annular flange with an outer diameter smaller than the inner diameter of the catheter 400 to retain movement clearance; the distal end is laser-welded to the center hole of the base 211 to form a non-removable axial connection, constituting a continuous rigid support frame from the base 211 to the limiting flange 217.

[0032] like Figure 4 , Figure 5As shown, valve component 214 is integrally molded from a conical polymer. Its central through-hole forms a sliding fit with retaining rod 212, and its axial movement range is determined by the effective rod length between limiting flange 217 and base 211. The proximal end face of valve component 214 is machined with an inclined sealing surface of 45 degrees ± 15 degrees. In its natural state, this surface forms a surface contact seal with the corresponding inclined surface inside the sealing ring 250. A medical-grade silicone layer is laminated onto the contact area surface to improve interface adaptability. The distal bottom surface of valve component 214 has a planar structure, directly contacting the proximal end of variable stiffness spring 213 to form a force transmission interface.

[0033] Preferably, the selection of the variable stiffness spring 213 covers a variety of nonlinear elastic elements, including variable pitch springs, nested combination springs, wave springs, and conical helical springs. When using a conical helical spring, its helical diameter increases linearly from the proximal end to the distal end. The minimum diameter at the proximal end forms a fitting gap with the outer diameter of the retaining rod 212, while the maximum diameter at the distal end remains in a non-contact state with the outer edge of the base 211. The spring as a whole is welded and fixed to the proximal end face of the base 211 through the distal large-diameter end, and the free end at the proximal end elastically abuts against the bottom surface of the valve 214. When the valve 214 is compressed and moved, each coil of the spring participates in compression deformation in order of increasing diameter, producing a nonlinear stiffness response that is first flexible and then stiff, realizing adaptive matching between the opening degree and the fluid pressure, and better coping with the excessive movement of the valve core caused by the frequent occurrence of instantaneous bladder high pressure in neurogenic bladder and the inability to reset in time due to inertial hysteresis.

[0034] like Figure 4 , Figure 5 As shown, the base 211 serves as a transition structure between the middle section 200 and the distal section 300. Its outer edge is fixed to the annular groove 216 on the inner wall of the catheter 400 by multiple sets of circumferentially distributed support arms 215. The support arms 215 are made of elastic stainless steel sheet by stamping, and the ends form barbs that bend towards the axis of the lumen. The tips of the barbs are sharp-angled to enhance the locking effect. A stepped locking groove is provided at the corresponding position on the inner wall of the catheter 400. Its cross-section is in the shape of two steps. When the support arm 215 is embedded in the annular groove 216, the tips of the barbs engage with the second step to form a bidirectional self-locking mechanism, which restricts the axial displacement of the base 211 and prevents radial swaying. An annular gap is maintained between the base 211 and the inner wall of the catheter 400. The height of this gap can be designed to be 1mm to 2mm depending on the model of the catheter 400, more preferably 1.2mm to 1.8mm, and even more preferably 1.4mm to 1.6mm. This gap is evenly distributed circumferentially between the connected support arms 215 to form a urine flow channel. Preferably, multiple sets of axially penetrating through holes are added to the end face of the base 211. The diameter of the through holes accounts for 30% to 40% of the cross-sectional area of ​​the base 211, forming a multi-path urine flow channel and significantly reducing local flow resistance.

[0035] like Figure 2 , Figure 3As shown, in the proximal region 100 of the catheter 400, a funnel-shaped flare 111 is provided at the initial (proximal) end of its lumen, with its diameter gradually decreasing from the proximal end to the distal end to form a converging flow channel 110. Multiple spiral guide vanes 121 are evenly distributed circumferentially on the inner wall of the converging flow channel 110. These spiral guide vanes 121 together constitute a vortex generator 120 to utilize centrifugal force to create a vortex in the urine, reducing sediment adhesion and improving drainage efficiency. The initial height of the spiral guide vanes 121 is designed proportionally to the inlet diameter of the converging flow channel 110, extending axially at a constant spiral angle, with the vane height gradually decreasing until it disappears completely. The surface of the spiral guide vanes 121 adopts a streamlined profile, with a smooth transition at the leading edge to eliminate flow separation, and a natural connection between the trailing edge and the tube wall, guiding the urine to form a vortex motion upon entry. The vortex generator 120 uses centrifugal force to migrate suspended particles towards the tube wall, while simultaneously reducing the velocity gradient in the central region and minimizing turbulent energy loss. The connection between the distal end (far end) of the proximal section 100 and the middle section 200 adopts a smooth transition design to avoid pressure fluctuations caused by abrupt changes in the cross-sectional area of ​​the flow channel. Preferably, the outer wall of the proximal section 100 is provided with a radiopaque line, which is co-extruded using a barium sulfate-containing silicone material, and appears clearly visible under X-ray to assist in positioning.

[0036] like Figure 6 As shown, in the distal segment 300 region of the catheter 400, a seamless drainage channel 320 is formed between the inner lumen at the distal end of the base 211 and the main body of the catheter 400 through injection molding. The outer wall of this drainage channel 320 is wrapped with an annular wire mesh skeleton 310, whose wires are woven in a diamond-shaped interlaced pattern to form a continuous mesh structure. Each weaving node is fused to the silicone tube wall through a hot-pressing process, resulting in a smooth transition between the wire mesh surface and the inner layer of the tube wall. This eliminates interference from surface protrusions on urine flow and resists external compression through the controllable deformation capability of the mesh. The geometric symmetry of the diamond-shaped mesh allows for uniform stress distribution when the catheter bends, and local mesh openings can expand or contract with deformation, dynamically maintaining the circular cross-section of the drainage channel 320 and preventing collapse.

[0037] Preferably, such as Figure 6 As shown, the inner wall of the drainage channel 320 is uniformly distributed with multiple axially extending strip-shaped recesses 321. The cross-section of the recesses 321 has a standard parabolic profile, with a gentle hydrodynamic depression forming in the central axis region, gradually rising to both sides and naturally merging with the curved surface of the pipe wall. The surface of the recesses 321 is treated with a multi-stage polishing process, significantly reducing wall friction resistance. The parabolic profile of the recesses 321 can guide the near-wall fluid to form a stable laminar boundary layer, while the gentle transition design of the recesses 321 edges can weaken the generation of turbulent vortices and reduce energy loss. In addition, the continuous axially extending structure of the recesses 321 forms directional flow guidance, which enhances the wall shear force to destroy the adhesion basis of bacterial biofilms, achieving a physical antibacterial effect.

[0038] When the intrabladder pressure increases, urine enters the constricting channel 110 from the proximal flared opening 111. Guided by the spiral guide vane 121, it forms a swirling flow and impacts the proximal sealing surface of the valve 214. When the hydraulic pressure reaches the opening threshold, the valve 214 slides distally under the action of fluid thrust, overcoming the resistance of the variable stiffness spring 213. At this time, the inclined sealing surface separates from the inner inclined surface of the sealing ring 250, forming a wedge-shaped guiding gap. As the displacement of the valve 214 increases, the large-diameter end of the conical spring begins to participate in compression, and the spring stiffness increases nonlinearly, making the opening of the valve 214 exponentially related to the pressure. This effectively improves the situation where the valve 214 is damaged due to excessive displacement caused by a sudden increase in bladder pressure. After passing through the guiding gap, the urine enters the distal drainage channel 320 through the gap between the base 211 and the support arm 215, and is discharged from the body in a stable laminar flow state under the guidance of the strip-shaped recess 321.

[0039] When the bladder pressure drops, the spring drives the valve 214 to reset through the nonlinear rebound force generated by the diameter difference. When it approaches the closed position, the valve 214 collides with the limiting flange 217 near the end of the retaining rod 212. The gradual sealing is achieved through elastic collision energy dissipation, avoiding the water hammer effect. At this time, the inclined sealing surface and the sealing ring 250 re-form a surface contact seal, completely blocking the reverse flow.

[0040] It should be noted that the above specific embodiments are exemplary. Those skilled in the art can devise various solutions inspired by the disclosure of this utility model, and these solutions all fall within the scope of this utility model and its protection scope. Those skilled in the art should understand that this utility model specification and its drawings are illustrative and do not constitute a limitation on the claims. The protection scope of this utility model is defined by the claims and their equivalents. Throughout the text, features introduced by "preferred" are merely optional and should not be construed as mandatory. Therefore, the applicant reserves the right to abandon or delete relevant preferred features at any time.

Claims

1. A backflow prevention catheterization device, comprising a catheter (400) and a check valve assembly (210) and a sealing ring (250) disposed within its inner cavity, characterized in that, The check valve assembly (210) includes a retaining rod (212) extending axially along the catheter (400), on which a valve member (214) is slidably sleeved; the valve member (214) has an inclined sealing surface on its proximal end face to form a sealing fit with the corresponding inclined surface on the inner side of the sealing ring (250); the retaining rod (212) is surrounded by a variable stiffness spring (213) whose proximal end abuts against the bottom surface of the distal end of the valve member (214); When the bladder pressure increases, the valve (214) is pushed by the urine to overcome the resistance of the variable stiffness spring (213) and slides to the distal end to form a flow channel between the inclined sealing surface and the sealing ring (250). When the pressure drops, the variable stiffness spring (213) drives the valve (214) to reset with a nonlinear rebound force, and achieves progressive closure by collision constraint with the limiting flange (217) that bulges radially at the proximal end of the retaining rod (212).

2. The catheterization device according to claim 1, characterized in that, The check valve assembly (210) has a base (211) at its distal end, and the distal end of the variable stiffness spring (213) abuts against the proximal end face of the base (211).

3. The catheterization device according to claim 2, characterized in that, The inner wall of the catheter (400) is provided with an annular groove (216) in the circumferential direction. The base (211) is fixed to the annular groove (216) by a plurality of radially peripheral support arms (215) so that a gap for urine to pass through can be formed between the base (211) and the inner wall of the catheter (400).

4. The urinary catheterization device according to claim 3, characterized in that, The end of the support arm (215) forms a barb structure that bends toward the axis of the catheter (400) lumen, and the inner wall of the annular groove (216) is provided with a stepped locking groove that matches the barb. When the support arm (215) is embedded in the annular groove (216), the barb and the stepped locking groove form a bidirectional self-locking mechanism, restricting the axial and radial displacement of the base (211).

5. The catheterization device according to claim 3, characterized in that, The catheter (400) is divided into three sections along its axial direction: a proximal section (100), a middle section (200), and a distal section (300). The check valve assembly (210) is located in the middle section (200) section. The sealing ring (250) serves as a transition structure between the proximal section (100) and the middle section (200), and the base (211) serves as a transition structure between the middle section (200) and the distal section (300).

6. The catheterization device according to claim 5, characterized in that, The proximal section (100) of the catheter (400) is provided with a gradually narrowing flow channel (110), the inlet of which has a funnel-shaped flared structure (111), forming a cross-section that gradually narrows from the proximal end to the distal end, so as to reduce the turbulent resistance of urine and guide the urine to converge towards the axis of the catheter (400).

7. The catheterization device according to claim 6, characterized in that, The gradually narrowing channel (110) is internally equipped with a vortex generator (120) that uses centrifugal force to create a vortex flow in the urine. The swirling generator (120) includes a plurality of spiral guide vanes (121) circumferentially distributed on the inner wall of the tapering channel (110). The height of the spiral guide vanes (121) gradually decreases from the proximal end to the distal end along the axial direction to avoid pressure fluctuations caused by abrupt changes in the flow channel.

8. The catheterization device according to claim 5, characterized in that, The distal segment (300) of the catheter (400) is fixedly provided with a drainage channel (320) in the inner cavity of the catheter (400) by means of integral molding, shape interlocking, welding or bonding. A skeleton (310) is provided between the drainage channel (320) and the inner wall of the catheter (400), wherein the skeleton (310) is configured as a ring-shaped wire mesh to wrap the drainage channel (320).

9. The catheterization device according to claim 8, characterized in that, The inner wall of the drainage channel (320) is provided with several strip-shaped depressions (321) extending along the direction of urine discharge. The cross-section of the depression (321) is parabolic, and its maximum depth is located in the central axis area of ​​the bottom wall. The depth smoothly decreases to be flush with the inner wall of the drainage channel (320) in all directions.

10. The catheterization device according to claim 2, characterized in that, The variable stiffness spring (213) is a conical helical spring with a helical diameter that increases from the near end to the far end. The large diameter end at the far end is welded and fixed to the end face of the base (211), and the small diameter end at the near end elastically abuts against the bottom surface of the far end of the valve (214). When the valve (214) slides, the conical helical spring generates a nonlinear stiffness response through the diameter difference.

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