Automatic limiting detection device
By using the water level sensor and lifting mechanism of the automatic limit detection device, the sample water level is dynamically adjusted, which solves the problem of unstable sample position in water and improves the accuracy of initial packaging inspection of sterile medical devices.
Patent Information
- Application Number
- CN202520657185.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-09
- Publication Date
- 2026-02-24
- Estimated Expiration
- 2035-04-09
AI Technical Summary
In existing tests for the integrity of the initial packaging of sterile medical devices, the position of the sample in water is not easily controlled, resulting in large measurement errors. In particular, the change in water level during the inflation process affects the experimental results.
An automatic limit detection device is adopted, which uses a water level sensor and a lifting mechanism in conjunction with a ball screw to achieve dynamic adjustment of the sample, ensuring that the sample is detected at a constant water level. The sample is fixed by a movable net and a guide rod to reduce errors caused by water level changes.
It improved the accuracy of the test results and reduced the measurement error caused by water level changes. In particular, it enabled stable control of the water level during the experiment for samples with a large coefficient of expansion.
Smart Images
Figure CN223940465U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of medical device testing technology, specifically an automatic limit detection device. Background Technology
[0002] The fundamental characteristic of a sterile medical device primary packaging system is its ability to prevent external microorganisms from entering the packaging. The sealed packaging material provides a sterile, clean environment for the contained medical device, maintaining its sterile state before use; therefore, primary packaging is considered a microbial barrier system. The integrity of the primary packaging material is essential for ensuring the safety of terminally sterilized medical devices throughout their shelf life; therefore, primary packaging is considered a component of sterile medical devices.
[0003] National Standard GB / T 19633.1—2015, "Packaging for Terminally Sterilized Medical Devices—Part 1: Requirements for Materials, Aseptic Barrier Systems and Packaging Systems," specifies the requirements and test methods for primary packaging materials, pre-formed primary packaging systems, aseptic barrier systems, and packaging systems intended to maintain the sterility of terminally sterilized medical devices before use. YY / T 0681 is a series of standards for "Test Methods for Packaging Materials for Sterile Medical Devices," which can be used to verify standard test methods and procedures that conform to the requirements of part of GB / T 19633.1.
[0004] YY / T 0681.5 "Test Methods for Sterile Medical Device Packaging - Part 5: Internal Pressure Method for Detecting Coarse Leaks (Bubble Method)" describes a test method that injects gas into the packaging to create a positive pressure condition and checks the packaging surface for signs of leakage, thus proving whether the tested packaging bag has any potential defects. A typical sign of leakage is the appearance of air bubbles on the surface of the packaging material. Therefore, the sample needs to be completely immersed in the medium water during the experiment for observation. Defective pores on the surface of the packaging material will generate bubbles under a certain internal pressure. The pressure point at which the first bubble is generated is the breathing point pressure of the pore. According to the liquid pressure formula P = ρgh, the interfering factor affecting the magnitude of the breathing point pressure of the same pore is the longitudinal position h of the test sample in the medium water. The closer the pore is to the water surface, the smaller h is, and the smaller the reaction force of the water pressure on the breathing point pressure. When the distance from the pore to the water surface is greater, the reaction force of the medium water pressure on the breathing point pressure of the pore is greater.
[0005] Based on the pressure theory formula, controlling the position of the sample in the water during the experiment can reduce the uncertainty of the measurement results and reduce measurement errors.
[0006] Currently, the method for fixing the position of the sample in water during this test is a one-time limiting fixation. During the inflation test, the packaging will expand underwater. As different samples have different specifications or expansion coefficients, the initial water level will change, making it difficult to control the sample to be at the standard required water depth, or to control the underwater depth of parallel samples uniformly, which becomes a type of uncertainty in the test results.
[0007] Based on this, the present utility model is proposed. Utility Model Content
[0008] This utility model addresses the shortcomings of existing technologies by providing an automatic limit detection device, the technical solution of which is as follows:
[0009] An automatic limit detection device includes a water tank, a movable net for limiting the test sample in the water tank, a movable frame for connecting the movable net, a lifting mechanism for driving the movable frame to rise and fall, and a water level sensor module for controlling the lifting mechanism. The water level sensor module includes a water level sensor installed on the movable frame.
[0010] As a further embodiment of this utility model, the lifting mechanism includes a stepper motor, a synchronous shaft driven to rotate by the stepper motor, and two lead screws. The stepper motor and the synchronous shaft are driven by bevel gears or by a worm gear and a worm. The synchronous shaft and the lead screws are driven by bevel gears. The lead screws and the moving frame are connected by ball nuts to form a ball screw.
[0011] As a further embodiment of this utility model, it also includes multiple guide rods, and the end of the movable frame is provided with a through hole that matches the guide rod, and the end of the movable frame is slidably connected to the guide rod.
[0012] As a further embodiment of this invention, a movable marking needle is slidably connected to the guide rod.
[0013] As a further embodiment of this utility model, the movable net includes a mesh plate, a fixed shaft is fixedly connected to the tail end of the mesh plate, a buckle is provided at the head end of the mesh plate, the tail end of the mesh plate is hinged to the movable frame through the fixed shaft, and the head end of the mesh plate is connected to the movable frame through the buckle.
[0014] As a further embodiment of this utility model, a water level gauge is slidably connected to the movable frame, and the water level sensor is fixed on the water level gauge, with the lower end of the water level sensor aligned with the zero-point scale line of the water level gauge.
[0015] As a further embodiment of this utility model, the water level sensor includes a columnar sensor body, with a “︸”-shaped confluence end at the lower end of the sensor body. A hydrophobic line array is provided on the outer wall of the sensor body. The hydrophobic line array is composed of multiple linear hydrophobic coatings arranged along the height direction of the sensor body, and the hydrophobic coatings are arranged at equal intervals. An electrode one located on one side of the confluence end and an electrode two located on the other side of the confluence end are provided at the lower part of the sensor body.
[0016] As a further embodiment of this utility model, a wave-damping ring is also fitted on the lower part of the sensor body, and the first electrode, the second electrode, and the bus terminal are all located inside the wave-damping ring.
[0017] A current technical shortcoming in laboratory testing of the integrity of the initial packaging of sterile medical devices is the control of the sample's position in water. Manual control by operators is the least stable approach, and this non-fixed constraint significantly affects the test data due to pressure changes in the water level, resulting in substantial operational errors. While fixed constraints can address measurement errors caused by water level shifts during the experiment, this method fails to adequately address the impact of the sample's expansion on the water level. As the sample expands, the water level rises, and although the pre-marked sample position remains unchanged, the immersion depth deviates due to the water level change, leading to similar measurement errors.
[0018] The automatic limit detection device described in this utility model can avoid both human operation errors and fixed errors. By fixing and dynamically adjusting the sample being tested, the sample is kept at a constant water level during the experiment, thus solving the uncertainty caused by water pressure and improving the accuracy of the experimental measurement results.
[0019] Compared with the prior art, the beneficial effects of this utility model are:
[0020] The automatic limit detection device described in this utility model is used for the integrity detection of the initial packaging of sterile medical devices. It can effectively solve the problem of inconsistent experimental positions of the test samples in water, especially for test samples with a large expansion coefficient. During the inflation process of the experiment, the device can dynamically adjust the experimental water depth of the test sample by utilizing automation, avoiding measurement errors caused by changes in water level during the experiment. Attached Figure Description
[0021] Figure 1 This is a schematic diagram of the structure of an automatic limit detection device according to the present invention;
[0022] Figure 2 This is a schematic diagram of the structure of the mobile net auction of this utility model;
[0023] Figure 3 This is a schematic diagram showing the distribution of the water level sensor and water level gauge of this utility model;
[0024] Figure 4 This is a schematic diagram of the structure of the water level sensor of this utility model;
[0025] Figure 5 This is a schematic diagram of the structure of the sensor body of this utility model. Detailed Implementation
[0026] The present invention will be described in detail below with reference to specific embodiments. These embodiments are merely some, not all, implementations of the present invention. All other implementations obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.
[0027] Example 1
[0028] like Figure 1 As shown, an automatic limit detection device includes a water tank 1, a movable mesh 6 for limiting the sample to be tested in the water tank 1, a movable frame 9 for connecting the movable mesh 6, a lifting mechanism for driving the movable frame 9 to rise and fall, and a water level sensor module for controlling the lifting mechanism. The water level sensor module includes a water level sensor 5 installed on the movable frame 9.
[0029] like Figure 3 As shown, the lifting mechanism includes a stepper motor 4, a synchronous shaft 7 driven by the stepper motor 4, and two lead screws 2. The stepper motor 4 and the synchronous shaft 7 are driven by bevel gears or by a worm gear and a worm. The synchronous shaft 7 and the lead screw 2 are driven by bevel gears. The lead screw 2 and the moving frame 9 are connected by ball nuts to form a ball screw.
[0030] The automatic limit detection device also includes multiple guide rods 3. The end of the movable frame 9 is provided with a through hole that matches the guide rod 3, and the end of the movable frame 9 is slidably connected to the guide rod 3.
[0031] A movable marker needle 8 is slidably connected to the guide rod 3.
[0032] During operation, the water level sensor module converts the signal from the water level sensor 5 into a working command to drive the stepper motor 4. The synchronous shaft 7 transmits the driving force of the stepper motor 4 to the lead screw 2. The rotation of the ball screw 2 controls the displacement of the moving frame 9. The sample being tested is limited by the movable mesh 6 on the moving frame 9, thus controlling the water level depth of the sample in the water tank 1 through the moving frame 9. The guide rod 3 enhances the stability of the moving frame 9 by being fixed in parallel, preventing single-axis instability during lead screw 2 movement. Simultaneously, the guide rod 3 also serves as the carrier for the moving marker needle 8.
[0033] Example 2
[0034] like Figure 2 As shown, the movable net 6 includes a mesh plate 61. The tail end of the mesh plate 61 is fixedly connected to a fixed shaft 62, and the head end of the mesh plate 61 is provided with a latch 63. The tail end of the mesh plate 61 is hinged to the movable frame 9 through the fixed shaft 62, and the head end of the mesh plate 61 is connected to the movable frame 9 through the latch 63.
[0035] The mesh plate 61 has a hollow structure, which can be used to pre-fix the sample to be tested when necessary; the mesh plate 61 can be locked on the moving frame 9 by the latch 63 to overcome the buoyancy generated by the sample to be tested during the experiment and ensure the stability of the mesh plate 61 during the experiment.
[0036] A water level gauge 11 is slidably connected to the movable frame 9, and the water level sensor 5 is fixed on the water level gauge 11. The lower end of the water level sensor 5 is aligned with the zero mark of the water level gauge 11.
[0037] The water level gauge 11 is slidably connected to the movable frame 9, and the two can be locked together with locking bolts. The horizontal section of the mesh plate 61 and the scale of the water level gauge 11 represent the water level control depth of the sample being tested in the experiment. That is, the depth of the sample being tested in the water tank 1 is controlled by controlling this scale value. For samples with a large expansion coefficient, the sample can be pre-inflated to confirm the highest point of the water level in the water tank 1 after expansion. The moving marker needle 8 on the guide rod 3 is used to mark the two sides of the water tank, and the resulting marking line is the zero point line of the experimental water level. The relative experimental position of the water level gauge 11 can be preset using this zero point line to avoid continuous adjustments caused by the expansion of the sample during the experiment, reduce unnecessary adjustments known beforehand during the experiment, and improve the continuity of the testing process and the efficiency of the experimental progress.
[0038] Example 3
[0039] like Figure 4 , 5As shown, the water level sensor 5 includes a cylindrical sensor body 51. A “︸”-shaped confluence end 511 is provided at the lower end of the sensor body 51. A hydrophobic line array is provided on the outer wall of the sensor body 51. The hydrophobic line array consists of multiple linear hydrophobic coatings 512 arranged along the height direction of the sensor body 51, with the hydrophobic coatings 512 arranged at equal intervals. An electrode 1 52 is located on one side of the confluence end 511, and an electrode 2 53 is located on the other side of the confluence end 511. A wave-damping ring 10 is also fitted over the lower part of the sensor body 51, and the electrode 1 52, electrode 2 53, and confluence end 511 are all located inside the wave-damping ring 10.
[0040] The function of the anti-wave ring 10 is to shield the water level sensor 5 from the disturbance ripples generated on the water surface by the underwater test sample during the inflation process, so as to ensure that the water surface around the water level sensor 5 is always in a static state and avoid intermittent interference caused by water ripples.
[0041] The working principle of the water level sensor 5 is the electrode method. It utilizes the conductivity of the medium water. When electrode 1 52 and electrode 2 53 come into contact with the water surface, a path is formed. This path is recognized by the water level sensor module, which then sends a working signal to the stepper motor 4 to move the movable net 6 upward. Once electrode 1 52 and electrode 2 53 leave the water surface, the path is broken. The water level sensor module recognizes this and stops driving the stepper motor 4, keeping the horizontal cross-section of the movable net 6 at the expected position in the water.
[0042] The hydrophobic linear array can accelerate the downward flow of liquid water contaminated on the surface of the water level sensor 5 to the confluence end 511. The special structure of the end section of the confluence end 511, coupled with the fact that the end of the confluence end 511 is lower than the cross section of electrode 1 52 and electrode 2 53, makes it easier for the liquid that has formed droplets to detach. This avoids short circuits between electrodes caused by the formation of droplets from the runoff on the surface of the water level sensor 5, which would otherwise send incorrect signals to the water level sensor module.
[0043] Furthermore, it should be understood that those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.
Claims
1. An automatic limit detection device, characterized in that: It includes a water tank (1), a movable net (6) for limiting the test sample in the water tank (1), a movable frame (9) for connecting the movable net (6), a lifting mechanism for driving the movable frame (9) to rise and fall, and a water level sensor module for controlling the lifting mechanism. The water level sensor module includes a water level sensor (5) installed on the movable frame (9).
2. The automatic limit detection device according to claim 1, characterized in that: The lifting mechanism includes a stepper motor (4), a synchronous shaft (7) driven by the stepper motor (4) to rotate, and two lead screws (2). The stepper motor (4) and the synchronous shaft (7) are driven by bevel gears or by a worm gear and a worm. The synchronous shaft (7) and the lead screw (2) are driven by bevel gears. The lead screw (2) and the moving frame (9) are connected by ball nuts to form a ball screw.
3. The automatic limit detection device according to claim 1, characterized in that: It also includes multiple guide rods (3), and the end of the movable frame (9) is provided with a through hole that matches the guide rod (3), and the end of the movable frame (9) is slidably connected to the guide rod (3).
4. The automatic limit detection device according to claim 3, characterized in that: A movable marker needle (8) is slidably connected to the guide rod (3).
5. The automatic limit detection device according to claim 1, characterized in that: The movable net (6) includes a mesh plate (61), the tail end of which is fixedly connected to a fixed shaft (62), the head end of which is provided with a buckle (63), the tail end of which is hinged to the movable frame (9) through the fixed shaft (62), and the head end of which is connected to the movable frame (9) through the buckle (63).
6. The automatic limit detection device according to claim 1, characterized in that: A water level gauge (11) is slidably connected to the mobile frame (9), and the water level sensor (5) is fixed on the water level gauge (11). The lower end of the water level sensor (5) is aligned with the zero mark of the water level gauge (11).
7. The automatic limit detection device according to claim 1, characterized in that: The water level sensor (5) includes a columnar sensor body (51). The lower end of the sensor body (51) is provided with a "︸"-shaped confluence end (511). The outer wall of the sensor body (51) is provided with a hydrophobic line array. The hydrophobic line array is composed of multiple linear hydrophobic coatings (512) arranged along the height direction of the sensor body (51). The hydrophobic coatings (512) are arranged at equal intervals. The lower part of the sensor body (51) is provided with an electrode one (52) located on one side of the confluence end (511) and an electrode two (53) located on the other side of the confluence end (511).
8. An automatic limit detection device according to claim 7, characterized in that: The lower part of the sensor body (51) is also fitted with a wave-shielding ring (10), and the first electrode (52), the second electrode (53) and the bus terminal (511) are all located inside the wave-shielding ring (10).