Disposable infusion pump infusion termination prompting device

Abstract

This invention discloses a disposable infusion pump infusion termination reminder device, belonging to the technical field of continuous infusion auxiliary devices. The device includes an elastic collar, a piezoelectric excitation element, a piezoelectric vibration pickup element, a signal processing unit, and a reminder component. The piezoelectric excitation element and the piezoelectric vibration pickup element are fixed to the inner wall of the elastic collar. The piezoelectric excitation element applies a sweep frequency excitation signal to the drug reservoir housing, and the piezoelectric vibration pickup element detects the mechanical vibration response frequency of the housing and the internal drug reservoir. The signal processing unit has a self-calibration function, automatically recording the reference frequency of the filling state when the device is first installed, and setting the emptying threshold to a preset multiple of the reference frequency. When the detected vibration response frequency exceeds the emptying threshold and remains unchanged for a period of time, it is determined that the drug reservoir is empty and the reminder component is triggered. This invention achieves adaptive emptying monitoring that is ready to use immediately without damaging the original structure of the infusion pump.

Description

Technical Field

[0001] This document relates to the field of infusion termination monitoring technology, and in particular to a disposable infusion pump infusion termination prompt device. Background Technology

[0002] Disposable infusion pumps rely on the elastic recoil force of the drug reservoir to drive the continuous infusion of medication. They have advantages such as compact structure, no need for external power supply, and controllable cost, and are widely used in clinical scenarios such as postoperative analgesia and tumor chemotherapy.

[0003] In clinical use, even those infusion pumps with transparent casings that allow for visual observation often lack a clear linear relationship between the morphological changes of the reservoir capsule as it gradually contracts and adheres to the internal support structure (such as the inner column) during drug emptying. Furthermore, the extremely slow infusion rate (typically 1 ml / h to 20 ml / h) and the duration of a single infusion (which can last from several hours to several days) make it difficult for healthcare professionals to accurately determine whether the infusion has stopped visually or through experience. The infusion pump itself does not provide any indication after the reservoir capsule empties; healthcare professionals can only estimate based on experience or check periodically. This makes it difficult to detect infusion termination promptly, especially at night or during busy periods, increasing the risk of complications such as venous inflammation, thrombosis, or infection.

[0004] To address the aforementioned issues, some solutions already exist. Chinese patent CN203861683U places a liquid level sensor inside the drug reservoir, but the sensor directly contacts the liquid, compromising the sterile barrier and posing a risk of contamination, and is incompatible with existing infusion pumps. Chinese patent CN203802884U uses a detection end clamped to the infusion tubing to determine emptiness, but this is prone to false alarms due to tubing bends or compression, and cannot provide early warnings.

[0005] Furthermore, products with remaining medication level indicators and infusion termination alarms are primarily electronic infusion pumps, which rely on built-in electronic sensors, battery power, and alarm modules to achieve these functions. However, electronic infusion pumps have the following problems: First, the electronic components contain metal parts, making them susceptible to electromagnetic interference, and patients cannot undergo special examinations such as MRI during infusion; second, the indicator device is integrated with the main body of the electronic pump, making it impossible to separate and adapt to disposable infusion pumps, and electronic pumps have high production costs and complex maintenance, which does not meet the cost control requirements of disposable products; third, electronic infusion pumps are relatively heavy, resulting in poor ease of use.

[0006] Chinese patent CN118067221A discloses a liquid level monitoring method based on the piezoelectric resonance principle. However, this solution is designed for industrial scenarios with fixed installation and manual calibration. The sensor is permanently fixed to a specific container and cannot be reused. Furthermore, it requires manual calibration before use, which also fails to meet the clinical use requirements of disposable infusion pumps.

[0007] Therefore, there is an urgent need for a disposable infusion pump infusion termination indication device that does not damage the original structure of the infusion pump, is reusable, has a self-calibration function, and is easy to operate. Summary of the Invention

[0008] This specification provides one or more embodiments of a disposable infusion pump infusion termination reminder device, which aims to solve the technical problems in the prior art where the drug reservoir cannot automatically remind the user after it is emptied, existing monitoring devices require manual calibration, cannot be reused, and are complex to operate.

[0009] A disposable infusion pump infusion termination notification device according to an embodiment of the present invention includes: The elastic collar, made of elastic material, has a ring structure and is used to be fitted onto the outer wall of the drug reservoir shell of a disposable infusion pump; A piezoelectric excitation element is fixed to the inner wall of the elastic collar and is used to apply an alternating excitation signal to the drug storage bladder shell. A piezoelectric vibration pickup element is fixed to the inner wall of the elastic collar and arranged adjacent to the piezoelectric excitation element. It is used to detect the mechanical vibration response of the drug storage bladder shell under the alternating excitation and output the corresponding vibration electrical signal. The signal processing unit is electrically connected to the input terminal of the piezoelectric excitation element and the output terminal of the piezoelectric pickup element. The signal processing unit includes a frequency detection circuit and a calibration circuit. The calibration circuit is used to automatically perform calibration after the elastic collar is fitted onto the drug storage bladder shell, and record the measured resonant frequency as a reference value for the filling state. The prompt component is electrically connected to the output terminal of the signal processing unit; The signal processing unit applies a sweep frequency excitation signal to the drug storage bladder shell through the piezoelectric excitation element and detects the vibration response frequency through the piezoelectric vibration pickup element. When the detected vibration response frequency exceeds a preset multiple of the filling state reference value and the frequency remains constant for a preset duration, the unit determines that the drug storage bladder is empty and triggers the prompt component.

[0010] The technical solution of this invention has the following beneficial effects.

[0011] First, the flexible collar allows for a detachable connection with the pump housing without damaging any of the pump's original structure. The installation process requires no tools and can be completed by hand.

[0012] Secondly, it has a self-calibration function. Once the device is put on, it automatically completes the calibration without the need for manual parameter setting. It is ready to use immediately and extremely easy to operate.

[0013] Third, it adopts the piezoelectric resonance detection principle, and judges the state of the medium inside the capsule by monitoring the change of the system's resonant frequency. The detection method is non-contact, does not come into contact with the drug solution, does not damage the sterile barrier, and has high safety.

[0014] Fourth, the resonant frequency is an intrinsic physical parameter of the system, which is less affected by interference factors such as ambient light and temperature fluctuations, resulting in high detection reliability.

[0015] Fifth, the device is reusable and only needs to be reinstalled when the infusion pump is replaced. The device automatically recalibrates, and the additional cost per use is extremely low.

[0016] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in one or more embodiments of this specification or in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall structure of the disposable infusion pump infusion termination indication device according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the unfolded internal structure of the elastic collar according to an embodiment of the present invention; Figure 3 This is an external schematic diagram of the unfolded elastic collar according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the signal processing unit according to an embodiment of the present invention. Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solutions in one or more embodiments of this specification, the technical solutions in one or more embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this specification, and not all of the embodiments. Based on one or more embodiments of this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this document.

[0020] The infusion termination indicator device described in this embodiment is compatible with conventional disposable infusion pumps. A disposable infusion pump, also known as a flexible infusion pump, mainly includes a rigid plastic housing, a flexible drug reservoir, a drug inlet, a flow limiter, and an infusion extension tubing.

[0021] The rigid plastic shell, cylindrical or spherical in shape, encloses the elastic drug reservoir, providing protection and shape maintenance. The shell is made of medical-grade rigid plastic such as PC or ABS. The elastic drug reservoir, made of medical-grade silicone, is highly elastic and contains the medication; it is the core driving component of the infusion pump. The drug inlet is located at one end of the shell, communicating with the inside of the reservoir for injecting the medication. It is usually equipped with a one-way valve to prevent backflow. A flow rate limiter, connected to the output end of the reservoir and employing a precision capillary or microporous membrane structure, controls the infusion rate within a preset range, commonly ranging from 1 ml / h to 20 ml / h. One end of the infusion extension tubing connects to the flow rate limiter, and the other end connects to the patient's intravenous access, used to deliver the medication into the body.

[0022] During use, medical staff inject medication into the reservoir through the injection port. Common sizes are 100ml, 150ml, 200ml, or 300ml. The reservoir expands elastically, converting the potential energy of the injected medication into elastic potential energy stored within the reservoir wall. Once the infusion begins, the reservoir continuously pushes out the medication using its own elastic recoil force. The medication is controlled within a constant flow rate by the flow rate limiter before entering the patient's body through the infusion extension tubing. Throughout the infusion process, the flow rate limiter ensures a relatively constant flow rate. As the medication continues to be output, the reservoir gradually contracts and decreases in volume. When all the medication has been output, the reservoir adheres tightly to the inner column, the elastic recoil force disappears, and the infusion automatically stops. For example, with a common 100ml size, the infusion time is approximately 20 hours at a flow rate of 5ml / h, and up to 100 hours (approximately 4 days) at a flow rate of 1ml / h. Due to the slow infusion rate and long duration, it is difficult to detect infusion termination in a timely manner, posing a safety hazard.

[0023] Example 1 like Figure 1 As shown, this embodiment discloses a disposable infusion pump infusion termination indication device, including an elastic collar 1, a piezoelectric excitation element 2, a piezoelectric vibration pickup element 3, a signal processing unit 4, an indication component, and a power supply module.

[0024] The elastic collar 1 is integrally molded from medical-grade silicone and has a cylindrical elastic clamp structure. The elastic collar 1 has an elastically expandable fitting hole. The normal inner diameter of the fitting hole is slightly smaller than the outer diameter of the drug reservoir shell of a commonly used disposable infusion pump. In use, it is elastically expanded and fitted onto the outer wall of the drug reservoir shell, and relies on its own elastic contraction force to tightly hug it, achieving tool-free and detachable fixation.

[0025] The axial width of the elastic collar 1 is 15mm to 25mm, ensuring sufficient contact area with the outer wall of the housing to prevent loosening or slippage. The inner wall of the elastic collar 1 is integrally formed with a silicone coupling layer. The silicone coupling layer is a thin and soft structure with a thickness of 0.2mm to 0.5mm, which fits tightly against the outer wall of the drug reservoir housing to reduce vibration signal transmission loss and improve detection sensitivity and stability.

[0026] The piezoelectric excitation element 2 is a circular piezoelectric ceramic sheet with a diameter of 8mm to 12mm and a thickness of 0.3mm to 0.8mm. It is fixedly attached to the inner wall of the elastic collar 1 and tightly adhered to the silicone coupling layer. The piezoelectric excitation element 2 is electrically connected to the output terminal of the signal processing unit 4 through a flexible shielded wire. Under the control of the signal processing unit 4, it is used to apply an alternating frequency sweep excitation signal of 100Hz to 10kHz to the drug reservoir shell, so that the shell generates stable mechanical vibration.

[0027] The piezoelectric vibration pickup element 3 uses a piezoelectric ceramic sheet with the same specifications, material, and operating frequency band as the piezoelectric exciter element 2. It is fixedly attached to the inner wall of the elastic collar 1 and arranged adjacent to the piezoelectric exciter element 2 with a spacing of 5mm to 15mm to avoid mutual interference. The piezoelectric vibration pickup element 3 is also closely attached to the silicone coupling layer 12 and electrically connected to the input end of the signal processing unit 4 through a flexible shielded wire. It is used to collect the mechanical vibration response of the drug storage bladder shell under excitation, convert the mechanical vibration signal into an electrical signal, and output it to the signal processing unit 4.

[0028] The outer wall of the elastic collar 1 is integrally formed with a sealed circuit compartment 14. The circuit compartment 14 has a rectangular box structure, which is waterproof and dustproof and can withstand clinical alcohol wiping disinfection. The outer wall of the circuit compartment 14 is provided with indicator light windows and sound outlets. Figure 2 This is a schematic diagram of the internal structure of the elastic collar in an embodiment of the present invention. Figure 3 This is an external schematic diagram of the unfolded elastic collar according to an embodiment of the present invention.

[0029] Figure 4 This is a schematic diagram of the signal processing unit according to an embodiment of the present invention. The signal processing unit 4 is encapsulated in a circuit compartment and includes a circuit board 41, a frequency detection circuit 43, a calibration circuit 45, a comparator 44, and a timing circuit 46.

[0030] Circuit board 41 is a rigid printed circuit board, fixedly installed inside circuit compartment 14. The input terminal of frequency detection circuit 43 is electrically connected to piezoelectric pickup element 3. It has a preamplifier, bandpass filter and waveform shaping unit. The preamplifier circuit is used to amplify the weak electrical signal output by piezoelectric pickup element. The bandpass filter circuit is used to filter out environmental interference signals. The waveform shaping unit is used to convert analog signals into digital signals that are easy to detect frequency. It is used to amplify, filter and convert weak vibration electrical signals into standard square wave signals to extract the current vibration response frequency.

[0031] The calibration circuit 45 is electrically connected to the frequency detection circuit 43 and is used to automatically perform calibration when the elastic collar 1 is fitted onto the drug reservoir shell, and record the currently measured resonant frequency as the filling state reference value f0.

[0032] The venting determination of this device is based on the following physical principle, according to the frequency formula of a resonant system: Where k is the system elastic coefficient, which remains essentially constant throughout the infusion process, and m is the equivalent mass participating in the vibration, including the mass of the shell itself and the effective mass of the drug reservoir and the internal drug solution tightly coupled to it. As the drug reservoir gradually empties from its full state, the equivalent mass m continuously decreases, and the system resonant frequency f continuously increases. As long as there is still drug solution output from the drug reservoir and the drug reservoir is still contracting, the equivalent mass m is in a continuous state of change, and the frequency f cannot remain constant for a long time. Only when the drug reservoir is tightly attached to the inner column and all the drug solution has been output does the equivalent mass m decrease to its minimum value and stop changing, at which point the frequency f reaches its maximum value and remains stable.

[0033] Based on the above physical principles, signal processing unit 4 employs dual decision-making logic: First, the signal processing unit 4 applies a frequency sweep excitation signal to the housing through the piezoelectric excitation element 2, and detects the current vibration response frequency through the piezoelectric vibration pickup element 3. The calibration circuit 45 sets the emptying judgment threshold to a preset multiple of the filling state reference value f0, which is greater than 1. The specific value of this preset multiple can be pre-calibrated based on the infusion pump's housing material, wall thickness, and clinical measurement data. Its function is to ensure that the device has entered the high-frequency region and eliminate instantaneous frequency fluctuations caused by accidental disturbances during the initial stage of infusion.

[0034] Second, the timing circuit 46 times the duration after the frequency exceeds a preset multiple and monitors the stability of the frequency. When If the frequency remains above a preset multiple and the frequency change is less than a preset fluctuation threshold within a preset time period, the emptying determination is ensured by the dual conditions of constant frequency and fluctuation limitation. The drug storage bag is determined to be completely emptied and the infusion is terminated, and then the prompt component is triggered.

[0035] In the aforementioned dual-judgment logic, maintaining a constant frequency for a preset duration is the core criterion for purging. The theoretical basis for this is that during infusion, the equivalent mass continuously changes, inevitably causing the frequency to change continuously and making a prolonged constant frequency impossible; conversely, after purging, the equivalent mass stops changing, and the frequency inevitably stabilizes. This logic is determined by fundamental laws of physics and does not rely on empirical data. The preset duration can be set from 10 to 60 seconds, and the preset fluctuation threshold can be set to ±1%. These parameters can be adaptively adjusted according to the casing material, wall thickness, and infusion rate of different infusion pump specifications.

[0036] Comparator 44 is electrically connected to frequency detection circuit 43 and calibration circuit 45 respectively, and is used to convert the real-time detected frequency. It is compared with the emptying threshold. The timing circuit 46 is electrically connected to the comparator 44, and the real-time frequency is... When the purging threshold is exceeded, a timing is started. When the high-frequency state continues for a preset duration and the frequency fluctuation is less than the preset fluctuation threshold, a valid purging judgment signal is output.

[0037] The notification components include LED indicator lights and a buzzer, both soldered onto circuit board 41. The LED indicator lights are positioned corresponding to the indicator light window and are used to display the operating status: a solid green light indicates normal monitoring, and a solid red light indicates the infusion has stopped. The buzzer is positioned corresponding to the sound outlet and is used to emit an intermittent audible alarm when the infusion stops.

[0038] The power supply module uses a CR2032 button battery, which is installed inside the circuit compartment 14 and is electrically connected to the piezoelectric excitation element 2, the piezoelectric vibration pickup element 3, the signal processing unit 4, and the prompting component, respectively, to provide a stable power supply for all electrical components.

[0039] The working process of this embodiment is as follows: 1. Installation and Automatic Calibration: Expand the elastic collar 1 and place it on the outer wall of the drug reservoir shell that is already filled with drug solution. The device automatically powers on and starts the calibration circuit 45, performing a complete frequency sweep test, acquiring the current resonant frequency and storing it as the filling reference value, while automatically calculating the emptying threshold. After calibration, the LED indicator light remains solid green, and the device enters the monitoring state.

[0040] 2. Real-time monitoring: The signal processing unit 4 controls the piezoelectric excitation element 2 to output frequency sweep excitation at a fixed cycle, and the piezoelectric vibration pickup element 3 collects the shell vibration frequency in real time and transmits it to the frequency detection circuit 43. As the liquid medicine is gradually output, the drug storage bladder contracts, the equivalent mass of the shell decreases, and the vibration frequency gradually increases.

[0041] 3. Emptying Judgment and Notification: When the real-time frequency exceeds 3 to 5 times the filling reference value, comparator 44 outputs a valid signal, and the timing circuit starts timing. If this high-frequency state remains stable without significant fluctuations and continues for a preset time, such as 30 seconds, the signal processing unit 4 confirms that the drug reservoir has been completely emptied and the infusion has terminated. It then drives the LED indicator to turn red and the buzzer to emit an intermittent alarm, reminding medical staff to replace the infusion pump.

[0042] 4. For reuse, after the prompt is triggered, the elastic collar 1 can be removed from the old injection pump housing and put on the new injection pump housing in a full state. The device will automatically recalibrate and can be put into use again without manual settings.

[0043] Example 2 Based on Example 1, this embodiment adopts an adaptive detection interval strategy to reduce the overall power consumption of the device and extend the service life of the power supply module, taking into account the characteristics of slow infusion speed and low resonant frequency change rate of the disposable infusion pump.

[0044] The signal processing unit 4 controls the piezoelectric excitation element 2 to periodically output a sweep frequency excitation at variable time intervals. Specifically, the signal processing unit 4 adjusts the frequency according to the real-time frequency. The detection interval is dynamically adjusted based on its proximity to the emptying judgment threshold. when When the value is far from the emptying threshold, it indicates that the infusion is still in the early stage and far from the emptying time. Therefore, a longer detection interval should be used, such as performing a frequency sweep detection every 30 minutes.

[0045] when When the infusion rate approaches the emptying threshold, it indicates that the infusion has entered the later stage and is about to be emptied. The detection interval is automatically shortened, such as performing a frequency sweep detection every 5 minutes.

[0046] when When the purging judgment threshold is reached or exceeded, it indicates that the threshold condition has been triggered and the purging confirmation stage is entered. The signal processing unit 4 switches to continuous monitoring mode and continuously detects the frequency until it stabilizes to confirm the purging status.

[0047] During the interval between two frequency sweep detections, signal processing unit 4 and its related circuits enter a low-power standby state, retaining only the necessary timed wake-up function. This adaptive detection interval strategy significantly reduces the average power consumption of the device while ensuring the reliability of the empty detection.

[0048] Taking a 100ml infusion pump, a flow rate of 5ml / h, and a total infusion time of 20 hours as an example, the scheme using a fixed interval of 10 minutes for detection requires about 120 frequency sweeps, while the adaptive interval strategy only requires about 40 frequency sweeps, reducing power consumption by about two-thirds and correspondingly extending the service life of the power supply module.

[0049] Example 3 This embodiment illustrates the usage scenarios and compatibility of this device when a patient undergoes a magnetic resonance imaging (MRI) examination, as well as the self-calibration process when the device is removed and re-worn.

[0050] Patient Zhang required continuous analgesia post-surgery, using a disposable infusion pump equipped with this infusion termination indicator. During treatment, the patient underwent a head MRI due to his condition.

[0051] Because MRI equipment generates a strong magnetic field, this field can potentially affect electronic devices containing metallic components. While the elastic collar and most components within the circuit compartment of this device are made of non-metallic materials, and the piezoelectric excitation element 2 and piezoelectric pickup element 3 utilize non-ferromagnetic piezoelectric ceramic sheets, the power supply module housing is made of stainless steel, which still presents uncertainties and risks in a strong magnetic field environment. Furthermore, the electronic circuitry in the signal processing unit 4 may be interfered with by the strong magnetic field. Therefore, in accordance with clinical operating procedures and safety principles, this device should be removed from the infusion pump housing before the patient enters the MRI examination room to ensure absolute safety.

[0052] Before the patient entered the MRI examination room, the nurse manually removed the elastic collar 1 from the infusion pump housing, a process that took approximately 3 seconds. After removal, the device automatically entered a low-power standby mode, but retained the previously stored calibration parameters (filling reference value f0 and emptying judgment threshold).

[0053] At this point, the disposable infusion pump detaches from the device and continues to infuse the medication independently using its own elastic recoil force, without affecting the infusion process. This is the fundamental difference between this device and an electronic infusion pump: the pump body and indicator device of an electronic infusion pump are integrated as one unit and cannot be separated; once the entire electronic infusion pump is removed, the infusion is interrupted. In contrast, this device and the infusion pump are designed separately; even after the indicator device is removed, the infusion pump can still operate normally independently.

[0054] The patient entered the examination room alone to complete the MRI examination, which lasted approximately 30 minutes. During this time, a disposable infusion pump continuously infused the medication at a constant rate.

[0055] After the patient returns to the ward following the examination, the nurse re-attaches the same elastic collar 1 to the infusion pump housing. Upon detecting the renewed contact with the housing, the device automatically awakens and executes a rapid self-calibration process: the piezoelectric excitation element 2 emits short sweep pulses, and the frequency detection circuit 43 acquires the current resonant frequency. The calibration circuit 45 will Compare with the stored filling baseline value f0. Because the infusion pump operates continuously during the MRI examination (approximately 30 minutes), the drug solution in the reservoir has decreased, the reservoir volume has shrunk accordingly, and the equivalent mass has decreased. Therefore, the current measured frequency... Typically higher than the original filling reference value f0. The calibration circuit 45 automatically updates the filling reference value to the current measured value. The system then recalculates the emptying threshold based on this. The entire recalibration process takes approximately 5 seconds. Once completed, the LED indicator returns to a solid green light, and the device resumes normal monitoring, continuing to monitor the infusion process of the remaining medication.

[0056] In contrast, if the patient is using an electronic infusion pump, the pump body and the indicator device are integrated into one unit, containing a large number of metal parts and sensitive electronic circuits. In the strong magnetic field environment of MRI, electronic infusion pumps face the following risks: (1) the metal parts may be attracted by the strong magnetic field, causing the device to shift or the patient to be injured; (2) the electronic circuits may be interfered with or damaged by the magnetic field, resulting in the failure of the alarm function or the pump body; (3) the device itself may interfere with the quality of MRI images. Therefore, patients usually need to remove the entire electronic infusion pump before the examination, resulting in the interruption of analgesia treatment. After the examination, the pump needs to be reconnected or replaced with a new one, which is complicated and affects the continuity of treatment.

[0057] This example demonstrates that the device employs a split design, allowing the indicator and infusion pump to be separated. Removing the indicator does not affect the normal operation of the infusion pump. After removal, the device automatically enters a low-power standby mode, retaining calibration parameters. Upon re-wearing, the device automatically completes calibration without requiring manual parameter setting; it is ready to use immediately.

[0058] The technical solution of this invention has the following beneficial effects.

[0059] First, the flexible collar allows for a detachable connection with the pump housing without damaging any of the pump's original structure. The installation process requires no tools and can be completed by hand.

[0060] Secondly, it has a self-calibration function. Once the device is put on, it automatically completes the calibration without the need for manual parameter setting. It is ready to use immediately and extremely easy to operate.

[0061] Third, it adopts the piezoelectric resonance detection principle, and judges the state of the medium inside the capsule by monitoring the change of the system's resonant frequency. The detection method is non-contact, does not come into contact with the drug solution, does not damage the sterile barrier, and has high safety.

[0062] Fourth, the resonant frequency is an intrinsic physical parameter of the system, which is less affected by interference factors such as ambient light and temperature fluctuations, resulting in high detection reliability.

[0063] Fifth, the device is reusable and only needs to be reinstalled when the infusion pump is replaced. The device automatically recalibrates, and the additional cost per use is extremely low.

[0064] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A disposable infusion pump end-of-infusion prompting device, characterized by, include: The elastic collar, made of elastic material, has a ring structure and is used to be fitted onto the outer wall of the drug reservoir shell of a disposable infusion pump; A piezoelectric excitation element is fixed to the inner wall of the elastic collar and is used to apply an alternating excitation signal to the drug storage bladder shell. A piezoelectric vibration pickup element is fixed to the inner wall of the elastic collar and arranged adjacent to the piezoelectric excitation element. It is used to detect the mechanical vibration response of the drug storage bladder shell under the alternating excitation and output the corresponding vibration electrical signal. The signal processing unit is electrically connected to the input terminal of the piezoelectric excitation element and the output terminal of the piezoelectric pickup element. The signal processing unit includes a frequency detection circuit and a calibration circuit. The calibration circuit is used to automatically perform calibration after the elastic collar is fitted onto the drug storage bladder shell, and record the measured resonant frequency as a reference value for the filling state. The prompt component is electrically connected to the output terminal of the signal processing unit; The signal processing unit applies a sweep frequency excitation signal to the drug storage bladder shell through the piezoelectric excitation element and detects the vibration response frequency through the piezoelectric vibration pickup element. When the detected vibration response frequency exceeds a preset multiple of the filling state reference value and the frequency remains constant for a preset duration, the unit determines that the drug storage bladder is empty and triggers the prompt component.

2. The apparatus of claim 1, wherein, The elastic collar is a ring-shaped or cylindrical structure, integrally molded from medical-grade silicone or thermoplastic elastomer.

3. The apparatus of claim 1, wherein, Both the piezoelectric excitation element and the piezoelectric pickup element are piezoelectric ceramic sheets or PVDF piezoelectric films, and their operating frequency bands are matched, with an operating frequency range of 100Hz to 10kHz.

4. The apparatus according to claim 1, characterized in that, The signal processing unit further includes a comparator and a timing circuit. The first input terminal of the comparator is connected to the output terminal of the frequency detection circuit, and the second input terminal of the comparator is connected to a reference voltage. The reference voltage corresponds to a preset multiple of the charging state reference value. The timing circuit is used to record the duration after the frequency exceeds the preset multiple.

5. The apparatus according to claim 1, characterized in that, The preset multiple is greater than 1.

6. The apparatus according to claim 1, characterized in that, The prompting component includes an LED indicator and a buzzer. The LED indicator is used to display the working status of the device, and the buzzer is used to issue an audible alarm when the infusion is terminated.

7. The apparatus according to claim 1, characterized in that, The outer wall of the elastic collar is provided with a circuit compartment, and the signal processing unit and the prompting component are encapsulated in the circuit compartment. The outer wall of the circuit compartment is provided with an indicator light window and a sound outlet.

8. The apparatus according to claim 1, characterized in that, It also includes a power supply module, which is a button battery or a rechargeable lithium battery, and the power supply module is electrically connected to the piezoelectric excitation element, the piezoelectric pickup element, the signal processing unit and the prompting component.

9. The apparatus according to claim 1, characterized in that, The inner wall of the elastic collar is also provided with a silicone coupling layer, which is located between the piezoelectric excitation element and the piezoelectric pickup element and the drug storage bladder shell, and is used to improve the transmission efficiency of vibration signals.

10. The apparatus according to claim 1, characterized in that, It also includes a wireless communication module, which is electrically connected to the output of the signal processing unit and is used to wirelessly transmit the infusion termination event to an external receiving terminal.

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