Dropping liquid monitoring device

Abstract

The invention relates to the technical field of automatic control, in particular to a dropping liquid monitoring device which comprises a shell, a liquid level sensor, a liquid level sensor and a liquid level sensor. The fixing piece is used for fixing the measuring pipe on the shell; the sensing module is fixed on the shell, the sensing module comprises a PMUT device, and the PMUT device forms vibration information through vibration of the side wall of the measuring tube; the control module is arranged in the accommodating cavity, the control module is in signal connection with the PMUT device, and the control module outputs liquid dropping result information according to the vibration information; the power supply module is used for supplying power to the control module and the PMUT device; the display module is in signal connection with the control module, the display module outputs display information according to the result information, and according to the dropping liquid monitoring device, accurate monitoring is guaranteed, meanwhile, the system is simplified, and low maintenance is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of automatic control, in particular to a liquid drop monitoring device. Background Art

[0002] The three core technical approaches currently adopted in the field of droplet monitoring are: weighing method (monitoring using weighing liquid bags), monitoring droplets (by monitoring droplet dynamics) and flow in the measuring tube (observing changes in flow velocity inside the measuring tube). However, each of these methods has its limitations. Specifically, although the weighing method is intuitive, it is easily disturbed by the vibration of the surrounding environment, resulting in unstable monitoring data. As for the two methods of monitoring droplets and flow velocity in measuring tubes, most of them rely on infrared or photoelectric sensors. This type of sensor has a complex structure and includes two major components: the transmitting source and the receiving source. It not only increases the complexity of the system, but also makes battery maintenance and replacement a frequent and tedious task, which greatly affects the continuous and stable operation of the equipment. Summary of the invention

[0003] The object of the present invention is to provide a drip monitoring system which simplifies the system and realizes low maintenance while ensuring accurate monitoring.

[0004] To achieve the above object, the present invention provides the following technical solution: a drip monitoring device, comprising:

[0005] A housing is formed with a receiving cavity;

[0006] A fixing member, used for fixing the measuring tube on the housing;

[0007] A sensing module, fixed on the housing, the sensing module comprising a PMUT device, the PMUT device forming vibration information through the vibration of the side wall of the measuring tube;

[0008] A control module is disposed in the accommodating cavity, the control module is connected to the PMUT device signal, and the control module outputs the result information of the dripping according to the vibration information;

[0009] A power supply module to supply power to the control module and the PMUT device; and

[0010] The display module is connected to the control module signal, and the display module outputs display information according to the result information.

[0011] Furthermore, the number of the PMUT devices is an even number, the even number of PMUT devices are arranged to form an even number of columns, and the PMUT devices between two adjacent columns are staggered and cross-arranged.

[0012] Furthermore, the sensing module includes a packaging body for packaging all the PMUT devices, the packaging body includes a transmission part for transmitting the vibration of the side wall to the PMUT device, the transmission part is made of polyurethane material, and the PMUT device is packaged in the transmission part.

[0013] Furthermore, the fixing member has a base fixed on the shell and elastic arms bent from both sides of the base, the base and the two elastic arms surround a clamping cavity for clamping the measuring tube, a monitoring window is provided on the base, and the transmission part abuts against the side wall through the monitoring window.

[0014] Furthermore, the transmission part is formed with a sensing surface, and the sensing surface is located in the clamping cavity.

[0015] Furthermore, the PMUT device comprises a piezoelectric layer and an electrode formed on the piezoelectric layer, wherein the electrode is located at a zero-charge position of the piezoelectric layer.

[0016] Furthermore, the shell is made of metal material, and the control module and the display module are connected by a shielded cable signal.

[0017] Furthermore, the power supply module is a battery arranged in the accommodating cavity.

[0018] Furthermore, the control module includes a charge amplification module, a data acquisition module and a signal processing module, the sensing module has a ground terminal and a signal output terminal, the ground terminal and the signal output terminal are both connected to the input terminal of the charge amplification module, the output terminal of the charge amplification module is connected to the input terminal of the signal acquisition module, and the output terminal of the signal acquisition module is connected to the input terminal of the signal processing module.

[0019] Furthermore, the control module forms a time-frequency diagram according to the vibration information, and obtains dripping speed information and dripping information according to the time-frequency diagram, and the result information includes the time-frequency diagram information, dripping speed information and dripping state information.

[0020] The beneficial effects of the present invention are as follows: the drip monitoring device of the present application utilizes the PMUT device to form vibration information through the vibration of the side wall of the measuring tube, and then outputs the result information of the dripping according to the vibration information through the control module, thereby ensuring accurate monitoring of the dripping. Among them, since the PMUT device only has a receiving source but no transmitting source, it helps to simplify the system, and it only requires microampere-level current, which helps to reduce battery maintenance. Therefore, the drip monitoring device simplifies the system and achieves low maintenance while ensuring accurate monitoring.

[0021] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of an infusion monitoring device shown in an embodiment of the present invention;

[0023] Figure 2 for Figure 1 A partially exploded view of an infusion monitoring device is shown;

[0024] Figure 3 For installation with measuring tube Figure 1 The structural schematic diagram of the infusion monitoring device shown;

[0025] Figure 4 This is a schematic diagram of the PMUT device structure layer shown in an embodiment of the present application;

[0026] Figure 5 A schematic diagram of the arrangement of a PMUT device shown in an embodiment of the present application;

[0027] Figure 6a It is the signal waveform under different drip irrigation rates;

[0028] Figure 6b It is the time-frequency diagram of drip irrigation signal under different drip irrigation rates;

[0029] Figure 7a It is the signal waveform diagram of different contact positions;

[0030] Figure 7b The signal waveforms at different tilt angles. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0033] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] The drip monitoring device is used to monitor the dripping situation, such as the dripping speed, etc. The drip monitoring device is widely used in intravenous infusion and agriculture. The following is an example of intravenous infusion.

[0036] Intravenous infusion is one of the commonly used treatment methods in modern medicine and is widely used in scenarios such as drug delivery, nutritional supplementation, and fluid resuscitation. Intravenous infusion delivers fluids to the patient's body by gravity or pumps. Controlling the drip rate is crucial in drug delivery, nutritional supplementation, and fluid resuscitation. First, drug delivery needs to maintain a specific concentration range. Too fast may cause side effects, and too slow may affect the efficacy; at the same time, the drug's kinetic process is also affected by the drip rate. Secondly, in nutritional supplementation, the drip rate needs to be adjusted according to the patient's metabolic needs. Too fast may cause hyperglycemia or electrolyte imbalance, while too slow may not meet the body's needs. In addition, during fluid resuscitation, controlling the drip rate helps avoid excessive heart burden and electrolyte imbalance, while providing medical staff with time to monitor patient reactions and adjust treatment plans in a timely manner. Finally, an appropriate drip rate can reduce the risk of infusion reactions and thrombosis. Therefore, in clinical practice, drip monitoring devices are the key to improving treatment effects and ensuring safety.

[0037] Please combine Figures 1 to 3The liquid drop monitoring device includes a housing 1, a fixing member 2 disposed on the housing 1, a sensing module 3 fixed on the housing 1, a control module (not shown) and a power supply module (not shown) disposed in the housing 1, and a display module (not shown) disposed outside the housing 1. In this embodiment, a receiving cavity (not shown) is formed in the housing 1, and the housing 1 includes a box body 11 and a cover plate 12 disposed on the box body 11, and the box body 11 and the cover plate 12 are arranged to form the receiving cavity. The control module and the power supply module are both fixed in the receiving cavity, and the sensing module 3 is partially located in the receiving cavity. The fixing member 2 is fixed on the front side plate 111 of the box body 11 to clamp the measuring tube 20, and the front side plate 111 is arranged opposite to the cover plate 12. The sensing module 3 includes a PMUT device, and the PMUT device forms vibration information through the vibration of the side wall of the measuring tube 20 (the vibration of the side wall is that when the droplet falls, the liquid in the measuring tube 111 vibrates, causing the side wall to vibrate, and the vibration will generate a vibration signal). The control module is connected to the PMUT device signal, and the control module outputs the result information of the dripping according to the vibration information. The power supply module is used to supply power to the control module and the PMUT device. The display module is separately arranged from the housing 1, and the display module is connected to the control module signal, and the display module outputs the display information according to the result information.

[0038] The drip monitoring device utilizes the PMUT device to generate vibration information through the vibration of the side wall of the measuring tube 20, and then outputs the drip result information according to the vibration information through the control module, thereby ensuring accurate monitoring of the drip. Among them, since the PMUT device only has a receiving source but no transmitting source, it helps to simplify the system, and it only requires microampere-level current, which helps to reduce battery maintenance. Therefore, the drip monitoring device simplifies the system and achieves low maintenance while ensuring accurate monitoring.

[0039] In this embodiment, the fixing member 2 and the housing 1 are fixed by fasteners (not shown). The fixing member 2 is located on the front side plate 111 of the housing 1. In this way, when the power supply module in the housing 1 needs to be replaced or maintained, it is only necessary to open the cover plate 12. The fixing member 2 is a chuck to facilitate the installation of the measuring tube 20. Specifically, the structure of the chuck is in the shape of a hoop with an opening. The fixing member 2 has a base 21 fixed on the front side plate 111 and two elastic arms 22 formed by bending and extending from both sides of the base 21. The base 21 and the two elastic arms 22 are surrounded to form a clamping cavity 23 for clamping the measuring tube 20. The transverse cross-section of the two elastic arms 22 is a variable diameter arc (i.e., composed of multiple arc segments with different diameters). A monitoring window 24 is provided on the fixing member 2 to facilitate the transmission of the vibration of the side wall to the PMUT device. The sensing module 3 is partially located in the monitoring window 24. By setting the monitoring window 24, it is helpful to reduce the structure of the housing 1.

[0040] The PMUT device can adopt an existing structure, which will not be described in detail here. Although the PMUT device is a known sensing element, the vibration signal generated when the droplet falls is very weak, so the PMUT device needs to have high sensitivity to monitor these tiny mechanical vibrations, and its sensitivity range needs to be between -170dB re 1V / μPa and -210dB re 1V / μPa.

[0041] In order to solve the above problems, the PMUT device is packaged in this application and is packaged with 1.5 MRayl polyurethane. Specifically, please combine Figures 1 to 5 The sensing module 3 includes a package body for encapsulating the PMUT device 33, the package body includes a substrate 32 and a packaging glue for fixing the PMUT device 33 on the substrate 32, the packaging glue is a transmission part 31 for transmitting the vibration of the side wall to the PMUT device 33, the transmission part 31 is made of a polyurethane material with an acoustic impedance of 1.5 MRayl, and the PMUT device 33 is encapsulated in the transmission part 31. The transmission part 31 abuts against the side wall of the measuring tube 20 through the monitoring window 24. The transmission part 31 is formed with a sensing surface, and the sensing surface is located in the clamping cavity 23.

[0042] By setting the transmission part 31 made of 1.5MRayl polyurethane material, the vibration of the side wall of the measuring tube 20 can be better transmitted to the PMUT device 33, which helps to improve the sensitivity of the PMUT device 33. After testing, the sensitivity of the PMUT device 33 of this embodiment is -170dB re 1V / μPa. In addition, since the sensing surface is located in the clamping cavity 23, when the measuring tube 20 is clamped by the fixing member 2, the sensing surface will be pressed against the measuring tube 20, and the part of the measuring tube 20 in contact with the sensing surface will be deformed after being pressed by the sensing surface, and the part becomes a plane that fits the sensing surface. In this way, the contact between the sensing surface and the measuring tube 20 is surface contact, which helps to effectively transmit the vibration of the measuring tube 20 to the PMUT device 33 and improve the signal amplitude. Of course, in other embodiments, the fixing member 2 can also be other structures such as a strap, and it only needs to be fixed on the housing 1 so that the measuring tube 20 can contact the sensing surface.

[0043] As mentioned above, the fixing member in this embodiment is in the shape of a hoop with an opening, and this structure can match and clamp several different sizes of measuring tubes, and because the transverse cross-section of the elastic arm 22 is in a variable diameter arc, the measuring tube 20 can be squeezed in the radial direction, ensuring the stable fixation of the measuring tube 20 while helping to improve the contact between the measuring tube 20 and the sensing surface. In order to improve the fixation, the inner side of the elastic arm 22 is coated with an anti-slip material to improve the fixation of the measuring tube 20.

[0044] The contact between the sensing surface and the measuring tube 20 is not to change the pressure between the two, but to increase the contact area between the two. Experiments have shown that the change in pressure only increases the sensitivity by a few percentage points, while the increase in the contact area between the measuring tube 20 and the transmission part 31 can increase the amplitude of the vibration signal by about twice.

[0045] The number of the PMUT devices 33 is an even number, and the even number of PMUT devices 33 are arranged to form an even number of columns, and the PMUT devices 33 between two adjacent columns are staggered. All PMUT devices 33 are packaged in the package body, and the PMUT devices 33 are staggered and cross-arranged to improve the coverage rate and further improve the sensitivity. In this embodiment, the number of PMUT devices 33 is twelve, and the twelve are divided into four columns, and three are one column, specifically referred to as the first column, the second column, the third column and the fourth column, wherein the six PMUT devices 33 in the first column and the second column are first connected in series, and the six PMUT devices 33 in the third column and the fourth column are first connected in series, and then in parallel.

[0046] As mentioned above, the PMUT device 33 can adopt the existing structure. However, it is found through application that the existing PMUT device 33 still has the following problems in practical application: when external sound pressure is applied to the surface of the PMUT device 33, causing the piezoelectric layer to vibrate, the stretching state of the center area and the edge is opposite, which will lead to different charge polarities. In order to solve this problem, please combine Figure 4 In this embodiment, the positive electrode 331 is set to be located at the zero charge position of the piezoelectric layer 332. The simulation results show that when the positive electrode 331 on the piezoelectric layer 332 covers 55-60% of the piezoelectric layer, the best receiving performance is obtained.

[0047] In the application of the drop monitoring device, when the drop falls, the main energy of the vibration signal is concentrated between 38Hz and 56Hz, which is very close to or even overlaps with the 50Hz power supply frequency interference, making the signal filtering design more complicated. In the prior art, the conventional method of directly filtering out the 50Hz interference (such as a band-stop filter) may also affect the useful signal of the drop vibration, resulting in signal loss or distortion. In order to solve this problem, the following solutions are adopted in this embodiment:

[0048] The first solution: the housing 1 is made of metal material, and the control module and the display module are connected by shielded cable signals;

[0049] The second solution: the power supply module is a battery arranged in the accommodating cavity;

[0050] The third solution: the control module includes a charge amplification module, a data acquisition module and a signal processing module. The sensing module 3 has a ground terminal and a signal output terminal. The ground terminal and the signal output terminal are both connected to the input terminal of the charge amplification module. The output terminal of the charge amplification module is connected to the input terminal of the signal acquisition module. The output terminal of the signal acquisition module is connected to the input terminal of the signal processing module.

[0051] In this embodiment, the dripping speed increasing signals will also interfere with each other. The second drop falling after the liquid surface has not yet calmed down will weaken the high-frequency signal amplitude at the moment of the drop falling. In order to solve this problem, the control module forms a time-frequency diagram based on the vibration information, and obtains the dripping speed information and dripping processing information based on the time-frequency diagram. The result information includes the time-frequency diagram information, the dripping speed information and the dripping state information. Specifically, the vibration information (in this case, the signal waveform) is converted into a signal processing module. Figure 6a The time-frequency diagram is drawn by wavelet transform (see Figure 6b ), and the signal processing module obtains dripping speed information and dripping processing information according to the time-frequency diagram, wherein the dripping processing information is used to determine whether dripping occurs through the processing module. It should be noted that the use of the time-frequency diagram also helps to avoid the use of complex filtering processing methods, which helps to simplify the system.

[0052] The time-frequency diagram information is the time-frequency diagram (see Figure 6b ), the display module displays the time-frequency diagram, through which medical staff can clearly observe the dripping speed.

[0053] In this application, in order to know whether the PMUT device 33 has an influence on the sensitivity of the PMUT device 33 when it is located at different relative positions of the liquid surface, see Figure 7a , in this experiment, the sensing surface ( Figure 7a The PMUT device 33 is shown in the figure) and is located 4 mm above the surface of the liquid, at the center, and 4 mm below the surface of the liquid. In the above three positions, when the measuring tube 20 is in a naturally drooping state, the installation position and the results are as follows. Figure 7aAs shown, the positive voltage peaks at these three locations are 22.9mV, 37.5mV and 61.6mV, respectively, and the negative voltage peaks are -11.7mV, -25.3mV and -45.7mV, respectively. Experiments were conducted at four locations below the liquid surface, and positive voltage peaks of 68.0mV, 55.6mV, 74.2mV and 61.8mV were measured. The single-sample t-test statistic is 0.832, which is less than the critical value of 3.182 and is not significantly different from 61.6mV. The positive voltage peak generated when the drop impacts the liquid surface and the attenuation at these three locations indicate that the pressure wave generated by the vibration is the main source of the signal. The positive voltage peak corresponds to the high-voltage area generated at the moment of impact, after which the pressure wave propagates outward and gradually decays, which is consistent with the observed signal attenuation pattern. There is no significant difference in the signal from the PMUT contact surface located below the liquid surface, indicating a high tolerance for the mounting position.

[0054] In order to find out whether the natural inclination of the measuring tube 20 has an influence on the sensitivity of the PMUT device 33. Figure 7b In this experiment, three different tilt states of the measuring tube 20 are given. The measuring tube 20 accurately controls the tilt angle by pulling the infusion tube with a belt. In these three different tilt states of the measuring tube 20, the drip impact position is in different relative positions with the circular sensor. Taking the first drip as an example, when the infusion chamber is located in the middle and right positions, the measured positive voltage peaks are 30mV and 101.6mV, respectively. In both cases, the signal shows a typical peak attenuation characteristic, and the first peak is significantly higher than the second peak, usually several times. In contrast, when the chamber is located on the left, the observed signal characteristics change significantly. The high peak value during the drip impact disappears and is replaced by two smaller peaks with values ​​of only 4.1mV and 10.8mV. This change in signal intensity is related to the impact position of the water drop, the propagation direction of the pressure wave, and the reflection characteristics of the wave. It is worth noting that although the waveform measured at the left position is significantly different from the typical waveform, the drip event can still be clearly identified by plotting time-frequency analysis, such as Figure 7b The results show that this method has good robustness under different tilt conditions.

[0055] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0056] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A drip monitoring device, characterized in that: include: A housing is formed with a receiving cavity; A fixing member, used for fixing the measuring tube on the housing; A sensing module, fixed on the housing, the sensing module comprising a PMUT device, the PMUT device forming vibration information through the vibration of the side wall of the measuring tube; A control module is disposed in the accommodating cavity, the control module is connected to the PMUT device signal, and the control module outputs the result information of the dripping according to the vibration information; A power supply module to supply power to the control module and the PMUT device; as well as The display module is connected to the control module signal, and the display module outputs display information according to the result information.

2. The drip monitoring device according to claim 1, characterized in that: The sensing module includes a packaging body for packaging all the PMUT devices, the packaging body includes a transmission part for transmitting the vibration of the side wall to the PMUT device, the transmission part is made of polyurethane material, and the PMUT device is packaged in the transmission part.

3. The drip monitoring device according to claim 1 or 2, characterized in that: The PMUT device has a piezoelectric layer and an electrode formed on the piezoelectric layer, wherein the electrode is located at a zero-charge position of the piezoelectric layer.

4. The drip monitoring device according to claim 2, characterized in that: The fixing member comprises a base fixed on the shell and elastic arms bent from both sides of the base. The base and the two elastic arms surround a clamping cavity for clamping the measuring tube. A monitoring window is provided on the base, and the transmission part abuts against the side wall through the monitoring window.

5. The drip monitoring device according to claim 4, characterized in that: The transmission part is formed with a sensing surface, and the sensing surface is located in the clamping cavity.

6. The drip monitoring device according to claim 1 or 2, characterized in that: The number of the PMUT devices is an even number, the even number of PMUT devices are arranged to form an even number of columns, and the PMUT devices between two adjacent columns are staggered and cross-arranged.

7. The drip monitoring device according to claim 1, characterized in that: The housing is made of metal material, and the control module and the display module are connected by shielded cable signals.

8. The drip monitoring device according to claim 1 or 7, characterized in that: The power supply module is a battery arranged in the accommodating cavity.

9. The drip monitoring device according to claim 1, characterized in that: The control module includes a charge amplification module, a data acquisition module and a signal processing module. The sensing module has a ground terminal and a signal output terminal. The ground terminal and the signal output terminal are both connected to the input terminal of the charge amplification module. The output terminal of the charge amplification module is connected to the input terminal of the signal acquisition module. The output terminal of the signal acquisition module is connected to the input terminal of the signal processing module.

10. The drip monitoring device according to claim 1, characterized in that: The control module forms a time-frequency diagram according to the vibration information, and obtains dripping speed information and dripping information according to the time-frequency diagram, and the result information includes the time-frequency diagram information, dripping speed information and dripping state information.

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