A negative pressure wound therapy device and its control method

Abstract

This invention discloses a negative pressure wound therapy device and its control method. The device includes a negative pressure adsorption module, a measurement module, a display module, a human-machine interaction module, and a control module. The control module includes a main control PCB circuit board and a main control chip. The main control chip is connected to the above modules, receives signals from the measurement module, transmits data signals to the display module and the human-machine interaction module, receives command signals from the human-machine interaction module, processes the data, and transmits control signals to the negative pressure adsorption module. By integrating multiple functional modules, including the human-machine interaction module, a continuously adjustable negative pressure design is achieved, making the treatment method more user-friendly and intelligent, and the device is small and portable. The control method uses fitting control of the negative pressure value and introduces an incremental PID control algorithm. These two elements form a dual-loop negative feedback system, enabling the system negative pressure to quickly stabilize at the user-set negative pressure value, improving accuracy and stability.

Description

Technical Field

[0001] This invention belongs to the field of medical device technology, and more specifically, relates to a negative pressure wound therapy device and its control method. Background Technology

[0002] Surgical site infections (SSIs) are widely recognized as a high global epidemiological burden and remain one of the most serious surgical complications. It is estimated that healthcare-associated infections (HAIs) add nearly $10 billion to the cost of US healthcare, with over $3.2 billion in HAI costs attributed annually to the treatment of SSI complications. In addition to increasing the financial burden on the national healthcare system, SSIs also lead to a range of serious consequences, including prolonged treatment times, increased morbidity, and mortality.

[0003] Numerous peer-reviewed articles have demonstrated that prophylactic use of negative pressure wound therapy (NPWT) on closed wounds can reduce surgical site infection (SSI) by more than 50%. NPWT refers to the continuous or intermittent application of sub-atmospheric pressure (typically -55 mmHg to -175 mmHg) to the wound surface using a wound dressing system. Clinical studies have shown that timely prophylactic use of NPWT devices before surgical site infection occurs can reduce the incidence of postoperative complications and promote wound healing. The use of NPWT devices to treat wounds has a comprehensive effect, including increasing local blood flow, eliminating local edema, reducing the accumulation of wound exudate, inhibiting bacterial growth, and promoting cell proliferation and granulation tissue growth. However, currently, negative pressure wound therapy machines used clinically are generally geared towards hospitalized critically ill patients, and therefore generally suffer from problems such as large size, high noise levels, disturbance to others during use, and inconvenience in operation.

[0004] Currently, NPWT technology is widely used in the treatment of various acute and chronic wounds, including acute soft tissue defects, various chronic (pressure, vascular, diabetic) ulcers, surgical incision dehiscence or infection, etc., and various negative pressure wound therapy devices have emerged on the market. Kunshan Weirui Medical Technology Co., Ltd., in its patent application "A Negative Pressure Wound Therapy Device" (application number: 201510071559.8, announcement number: CN104667360A), proposed an NPWT device with a rotatable collection bottle. This invention patent takes into account that the sample observation chamber in the collection bottle can only store a certain amount of wound exudate for medical staff to observe, and the wound exudate in the sample observation chamber needs to be emptied regularly. The collection device connects to the negative pressure source and achieves the function of emptying wound exudate. However, this invention mainly improves the convenience for medical staff to perform nursing care and sampling after the user's treatment, and is not suitable for users who want to treat at home. Xiamen Shengci Medical Equipment Co., Ltd., in its patent application "Negative Pressure Wound Treatment Device, System and Method" (Application No.: 201711497896.9, Publication No.: CN109985283A), proposed a portable negative pressure wound treatment device. This device connects to a dressing and includes a shell, control circuit board, pump, and suction tubing, achieving a good negative pressure treatment function while maintaining a small size. Although the core functions are relatively complete, the invention lacks intelligent expansion functions that align with current social development trends. Furthermore, operation relies solely on buttons, resulting in a less intelligent and user-friendly human-computer interaction that needs improvement. Summary of the Invention

[0005] The purpose of this invention is to address the above-mentioned shortcomings by providing a negative pressure wound therapy device and its control method.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0007] A negative pressure wound therapy device, including

[0008] The negative pressure adsorption module includes a wound adsorption device and a negative pressure suction channel connected thereto. The negative pressure suction channel is connected to a negative pressure sensor, a vacuum pump and a drainage bottle respectively via a T-junction.

[0009] The measurement module includes a temperature and humidity sensor, an air pressure sensor, a negative pressure sensor, and a liquid level monitor, used to monitor ambient temperature and humidity, air pressure, negative air pressure, and the liquid level inside the drainage bottle;

[0010] The display module, including a touch screen and a display screen, is used to display the monitoring data of the measurement module and the instrument's operating status;

[0011] The human-computer interaction module includes an operation interface displayed on a touch screen, which displays real-time environmental parameters and operating status, and sets different working modes and parameters;

[0012] The control module includes a main control PCB circuit board, which is equipped with a main control chip. The main control chip is connected to the above-mentioned modules, receives signals from the measurement module, transmits data signals to the display module and the human-machine interaction module, receives instruction signals from the human-machine interaction module, processes the data, and transmits control signals to the negative pressure adsorption module.

[0013] Furthermore, the wound adsorption device consists of a dressing and a medical restraint strap, and uses medical-grade materials for negative pressure wound treatment, which can effectively improve the treatment effect.

[0014] Furthermore, the touchscreen, display screen, temperature and humidity sensor, and air pressure sensor are all housed within the casing of the therapeutic device, while the negative pressure sensor and vacuum pump are located inside the device. The drainage bottle is mounted externally via a drainage bottle bracket. This design makes the overall structure of the therapeutic device more integrated and compact, making it easy to carry.

[0015] Furthermore, the human-computer interaction module also includes a cloud-based mini-program, and the main control PCB circuit board is equipped with a WiFi module. The main control chip connects to and controls the WiFi module to connect to the cloud-based mini-program through the Internet of Things.

[0016] Furthermore, the human-computer interaction module also includes a host computer. The main control chip is connected to the host computer via a USB serial port. The host computer is used to display the current working status of the therapeutic device and various parameters of the surrounding environment, as well as to set the working parameters.

[0017] Furthermore, it also includes an alarm module, including an alarm indicator light set on the housing of the therapeutic device and a buzzer module set on the main control PCB circuit board. The main control chip receives the monitoring results of the liquid level monitor, and controls the alarm indicator light and the buzzer module to sound an alarm when the liquid level in the drainage bottle exceeds the threshold, and switches the working state of the therapeutic device to pause. The alarm indicator light also displays the status signal of the current working state.

[0018] Furthermore, the alarm indicator light can be an RGB full-color LED strip, which can automatically switch colors as the current status signal as the working state changes.

[0019] Furthermore, it also includes a speaker module mounted on the main control PCB circuit board, which can be controlled by the main control chip to broadcast voice messages to remind the user of the current status when treatment starts, pauses, or stops.

[0020] Furthermore, it also includes touch buttons, which are located on the housing of the therapeutic instrument and connected to the main control PCB circuit board, for controlling the start, pause, stop and emergency braking of the instrument.

[0021] Furthermore, the touch buttons have a higher control priority than the human-computer interaction module. This allows for emergency braking of the system, unconditionally suspending the treatment device and significantly improving its safety.

[0022] Furthermore, the therapeutic device is equipped with a UPS (Uninterruptible Power Supply) for power supply, and the casing of the therapeutic device is equipped with a charging interface for the UPS. The UPS ensures the therapeutic effect of the device under special circumstances, such as sudden power outages or when the patient needs to be treated while moving.

[0023] Furthermore, the display screen is an e-ink screen used to display the operating status of the therapeutic device and environmental parameters, including but not limited to real-time time, real-time temperature and humidity, real-time air pressure, WiFi status, and the current operating status and remaining treatment time of the therapeutic device. This not only allows users to conveniently view the treatment status in real time but also saves on the instrument's power consumption.

[0024] Furthermore, the touchscreen display includes switchable SCREEN, SET, and MODE interfaces.

[0025] The SCREEN interface is used to display the current time, ambient temperature, humidity, and air pressure read by the system, and has a touch hotspot for controlling the start, pause, and end of the treatment device's working status.

[0026] The SET interface is used for, but is not limited to, selecting the working mode, turning WiFi on / off, turning voice prompts on / off, and setting the automatic sleep time of the therapy device;

[0027] The MODE interface is used to set treatment parameters for each working mode, including but not limited to treatment time, maximum negative pressure value, minimum negative pressure value, peak-to-trough alternation time, and peak-to-trough ratio.

[0028] The present invention also provides a control method for a negative pressure wound therapy device, used to control the negative pressure of the device, comprising the following steps:

[0029] The negative pressure normalization coefficient is calculated by comparing the set target negative pressure value with the current negative pressure value of the therapeutic device.

[0030] The PWM duty cycle coefficient is fitted by a negative voltage normalized proportional coefficient.

[0031] The PWM duty cycle of the vacuum pump is controlled by the PWM duty cycle coefficient obtained by fitting.

[0032] When the negative pressure inside the wound adsorption device reaches 90% of the set target negative pressure value, an incremental PID control algorithm is used to calculate and control the pumping speed of the vacuum pump to stabilize the negative pressure inside the wound adsorption device at the target negative pressure value.

[0033] The above method adjusts the duty cycle by controlling the negative pressure value of the current system. The closer the negative pressure value is to the target value, the slower the vacuum pump needs to pump. The higher the duty cycle, the slower the vacuum pump pumps.

[0034] Furthermore, the operating modes of the therapeutic device include peak / trough mode, user-defined mode, and automatic mode.

[0035] The target negative pressure value of the peak-valley mode is set alternately between peak negative pressure and valley negative pressure, wherein the peak-valley alternation time and the peak-valley ratio coefficient can be adjusted through the human-computer interaction module.

[0036] The target negative pressure value in the user-defined mode can be freely set by the user.

[0037] The target negative pressure value in the automatic mode is randomly selected between the maximum and minimum negative pressure values ​​set by the user.

[0038] Furthermore, the formula for calculating the negative pressure normalization proportional coefficient is as follows:

[0039]

[0040] Wherein, pressure_value is the current negative pressure value of the therapeutic device, pressure_set is the set target negative pressure value, and pressure_ratio is the negative pressure normalization ratio coefficient.

[0041] Furthermore, the fitting function for fitting the PWM duty cycle coefficient is:

[0042] obj = 464.8 pressure_ratio 3 -733 pressure_ratio 2 +393.3 pressure_ratio -46.4

[0043] Where obj is the PWM duty cycle coefficient and pressure_ratio is the negative pressure normalization ratio coefficient.

[0044] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0045] The negative pressure wound therapy device of the present invention integrates multiple functional modules, including human-computer interaction, and realizes a continuously adjustable negative pressure design. It can select intermittent or continuous negative pressure treatment mode, making the treatment method more humane and intelligent. It is also small in size and easy to carry.

[0046] The human-computer interaction module of this invention is designed with a more intelligent and user-friendly interface, presenting rich functions in a graphic style, simplifying the operation process to the greatest extent, and improving the user experience of this invention.

[0047] This invention features priority-based touch buttons that enable emergency braking of the system, causing the therapeutic device to unconditionally enter a pause state, significantly improving product safety.

[0048] The control method of the negative pressure therapy device described in this invention, by fitting the negative pressure value and introducing an incremental PID control algorithm, forms a dual-loop negative feedback system, which enables the system negative pressure to stabilize at the negative pressure value set by the user within two seconds, greatly improving accuracy and stability. Attached Figure Description

[0049] Figure 1 This is a system control structure diagram of a negative pressure wound therapy device provided in Example 1;

[0050] Figure 2 This is a perspective view of the shell structure of the negative pressure wound therapy device described in Example 1;

[0051] Figure 3 This is a schematic diagram of the front view of the negative pressure wound therapy device described in Example 1;

[0052] Figure 4 This is a top view of the negative pressure wound therapy device described in Example 1;

[0053] Figure 5 This is a schematic diagram of the left side of the negative pressure wound therapy device described in Example 1;

[0054] Figure 6 This is a SCREEN interface diagram of the touchscreen display operation interface described in Example 1;

[0055] Figure 7 This is a SET interface diagram of the touchscreen display operation interface described in Example 1;

[0056] Figure 8 This is a MODE interface diagram of the touchscreen display operation interface described in Example 1;

[0057] Figure 9 This is a diagram of the display interface of the e-ink screen described in Example 1;

[0058] Figure 10This is an interface diagram of the WeChat mini program described in Example 1;

[0059] Figure 11 This is a diagram of the display interface of the host computer described in Example 1;

[0060] Figure 12 This is a control relationship block diagram of the method described in Example 2;

[0061] Figure 13 This is a flowchart illustrating the operation of the negative pressure wound therapy device described in this invention.

[0062] In the diagram: 1. Touch screen, 2. Alarm indicator light, 3. Touch button, 4. E-ink screen, 5. UPS uninterruptible power supply, 6. Temperature and humidity sensor, 7. Air pressure sensor, 8. Drainage bottle bracket, 9. Liquid level monitor, 10. USB serial port, 11. Charging interface. Detailed Implementation

[0063] Preferred embodiments of the present invention will now be described in more detail with reference to the accompanying drawings and specific examples.

[0064] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0065] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0066] Example 1

[0067] This embodiment provides a negative pressure wound therapy device, the system control structure of which is as follows: Figure 1 As shown, including

[0068] The negative pressure adsorption module includes a wound adsorption device and a negative pressure suction channel connected thereto. The negative pressure suction channel is connected to a negative pressure sensor, a micro vacuum pump and a drainage bottle via a three-way valve.

[0069] The measurement module, including the clock module on the main control PCB circuit board, as well as temperature and humidity sensors, air pressure sensors, negative pressure sensors and liquid level monitors, is used to monitor the ambient temperature, humidity and air pressure, negative air pressure and liquid level in the drainage bottle, measure the working environment of the system in real time, and can provide parameters for control to the other modules.

[0070] The display module, including a touch screen and an e-ink screen, is used to display the monitoring data of the measurement module and the instrument's operating status;

[0071] The human-computer interaction module includes an operation interface displayed on a touchscreen for displaying real-time environmental parameters and operating status, and setting different working modes and parameters; it also includes a cloud-based mini-program and a host computer. A WiFi module is provided on the main control PCB circuit board, and the main control chip connects to and controls the WiFi module to connect to the cloud-based mini-program via the Internet of Things; the main control chip connects to the host computer via a USB serial port 10.

[0072] The control module includes a main control PCB circuit board, which is equipped with a main control chip and various expansion modules. The main control PCB circuit board is connected to the core board of the main control chip and acts as a converter. The main control chip is connected to the above modules, receives signals from the measurement module, transmits data signals to the display module and the human-machine interaction module, receives instruction signals from the human-machine interaction module, processes the data, and transmits control signals to the negative pressure adsorption module.

[0073] like Figures 2 to 5 As shown, the touchscreen 1, e-ink screen 4, temperature and humidity sensor 6, and air pressure sensor 7 are all housed within the casing of the therapeutic device. The negative pressure sensor and vacuum pump are located inside the therapeutic device. The miniature vacuum pump is positioned within a clip on the base of the outer casing to generate a negative pressure environment inside the negative pressure suction channel. The drainage bottle is mounted externally to the therapeutic device via a drainage bottle bracket 8.

[0074] The therapeutic device's casing is also equipped with a touch button 3, which is connected to the main control PCB board and used to control the device's start, pause, stop, and emergency braking. The touch button 3 has a higher control priority than the human-machine interface module. This allows for system emergency braking, unconditionally suspending the therapeutic device and significantly improving its safety.

[0075] The therapeutic device is equipped with a UPS (Uninterruptible Power Supply) for power supply, and its casing has a UPS charging interface 11. The UPS ensures the therapeutic effect of the invention under special circumstances, such as sudden power outages or when the patient needs treatment while moving. The main control chip of the therapeutic device is also connected to a host computer via a USB serial port to display the current operating status of the therapeutic device and various parameters of the surrounding environment.

[0076] The therapeutic device described in this embodiment also includes an alarm module, comprising an alarm indicator light 2 mounted on the device housing and a buzzer module mounted on the main control PCB circuit board. The main control chip receives the monitoring results from the liquid level monitor 9 and controls the alarm indicator light 2 and the buzzer module to sound an alarm when the liquid level in the drainage bottle exceeds a threshold, and switches the therapeutic device to a paused state. The alarm indicator light 2 also displays the status signal of the current working state. In this embodiment, the alarm indicator light 2 uses an RGB full-color LED strip, which can automatically change color as the current status signal according to the switching of working states.

[0077] In this embodiment, the touchscreen 1 is an IPS capacitive touchscreen. The operation interface displayed on the touchscreen 1 includes a SCREEN interface, a SET interface, and a MODE interface that can be switched between each other, such as... Figures 6 to 8 As shown, the SCREEN interface is used to display the current time, ambient temperature, humidity, and air pressure read by the system, and has touch hotspots for controlling the start, pause, and end of the treatment device's working status.

[0078] The SET interface is used for, but is not limited to, selecting the working mode, turning WiFi on / off, turning voice prompts on / off, and setting the automatic sleep time of the therapy device;

[0079] The MODE interface is used to set treatment parameters for each working mode, including but not limited to treatment time, maximum negative pressure value, minimum negative pressure value, peak-to-trough alternation time, and peak-to-trough ratio.

[0080] The e-ink screen 4 described in this embodiment has the following display interface: Figure 9 As shown, this display shows the operating status of the therapeutic device and environmental parameters, including but not limited to real-time time, real-time temperature and humidity, real-time air pressure, WiFi status, as well as the current operating status of the therapeutic device and the remaining treatment time. This allows users to conveniently view the treatment status in real time while also saving on the instrument's power consumption.

[0081] The main control PCB circuit board described in this embodiment is equipped with multiple functional modules, including a WiFi module, a speaker module, an active buzzer module, and a Matlab host computer application. The WiFi module is used to connect to an IoT server, enabling real-time viewing and adjustment of the therapeutic instrument's parameters via a WeChat mini-program in the cloud. The interface of the WeChat mini-program is as follows: Figure 10As shown; the Speaker module can broadcast voice prompts to remind the user of the current status when treatment starts, pauses, and stops, while the buzzer will sound an alarm when the water level monitoring module detects that the liquid level in the drainage bottle exceeds the threshold. The host computer interacts with the main control chip via USB serial port 10, allowing the user to observe the current working status of the treatment device and various parameters of the surrounding environment in real time, as well as set the working parameters. The host computer's display interface is shown below. Figure 11 As shown.

[0082] Example 2

[0083] This embodiment provides a control method for a negative pressure wound therapy device, used to control the negative pressure of the negative pressure wound therapy device described in Embodiment 1, the control relationship being as follows: Figure 12 As shown, it includes the following steps:

[0084] The negative pressure normalization coefficient is calculated by comparing the set target negative pressure value with the current negative pressure value of the therapeutic device.

[0085] The PWM duty cycle coefficient is fitted using a negative voltage normalized proportional coefficient, and the fitting function is:

[0086] obj = 464.8 pressure_ratio 3 -733 pressure_ratio 2 +393.3 pressure_ratio -46.4

[0087] Where obj is the PWM duty cycle coefficient and pressure_ratio is the negative pressure normalization ratio coefficient;

[0088] The formula for calculating the negative pressure normalization ratio is as follows:

[0089]

[0090] Where pressure_value is the current negative pressure value of the therapeutic device, pressure_set is the set target negative pressure value, and pressure_ratio is the negative pressure normalization ratio coefficient;

[0091] The PWM duty cycle of the vacuum pump is controlled by the PWM duty cycle coefficient obtained by fitting.

[0092] When the negative pressure inside the wound adsorption device reaches 90% of the set target negative pressure value, an incremental PID control algorithm is used to calculate and control the pumping speed of the vacuum pump to stabilize the negative pressure inside the wound adsorption device at the target negative pressure value.

[0093] The above method adjusts the duty cycle by controlling the negative pressure value of the current system. The closer the negative pressure value is to the target value, the slower the vacuum pump needs to pump. The higher the duty cycle, the slower the vacuum pump pumps.

[0094] The working modes of the therapeutic device described in this embodiment include peak-valley mode, user-defined mode and automatic mode. The target negative pressure value of the peak-valley mode is set alternately between peak negative pressure and valley negative pressure. The peak-valley alternation time and the peak-valley ratio coefficient can be adjusted through the human-computer interaction module.

[0095] The target negative pressure value in the user-defined mode can be freely set by the user.

[0096] The target negative pressure value in the automatic mode is randomly selected between the maximum and minimum negative pressure values ​​set by the user. After the user starts the treatment device through the operation interface or touch buttons, the system will first determine the working mode set by the user in the SET interface, and then set the running status to RUN.

[0097] The complete operating procedure of the negative pressure wound therapy device described in this invention is as follows: Figure 13 As shown.

[0098] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and principles of the described embodiments, and these modifications and variations should also be considered within the scope of protection of the present invention.

Claims

1. A negative pressure wound therapy apparatus, characterized in that Comprising A negative pressure suction module comprising a wound suction device and a negative pressure suction channel connected thereto, the negative pressure suction channel being connected to a negative pressure sensor, a vacuum pump and a drainage bottle respectively; A measurement module comprising a temperature and humidity sensor, a barometric pressure sensor, a negative pressure sensor and a liquid level monitor for monitoring the ambient temperature and humidity, barometric pressure, negative pressure and liquid level in the drainage bottle; A display module comprising a touch screen and a display screen for displaying the monitoring data of the measurement module and the operating status of the instrument; A human-computer interaction module comprising an operating interface displayed on the touch screen for displaying real-time environmental parameters and operating status and setting different working modes and parameters; A control module comprising a main control PCB circuit board, the main control PCB circuit board being provided with a main control chip, the main control chip being connected to the above-mentioned modules, receiving the measurement module signal, transmitting the data signal to the display module and the human-computer interaction module, receiving the human-computer interaction module instruction signal, performing data processing and then transmitting the control signal to the negative pressure suction module; The control module is configured to perform the following steps: A negative pressure normalization proportion coefficient is calculated by the set target negative pressure value and the current negative pressure value of the therapeutic instrument, The PWM duty cycle coefficient is fitted by the negative pressure normalization proportion coefficient; The PWM duty cycle of the vacuum pump is controlled by the fitted PWM duty cycle coefficient; When the negative pressure value inside the wound suction device reaches 90% of the set target negative pressure value, an incremental PID control algorithm is used for calculation, and the negative pressure inside the wound suction device is stabilized at the target negative pressure value by controlling the suction speed of the vacuum pump.

2. The negative pressure wound therapy apparatus of claim 1, wherein, The touch screen, display screen, temperature and humidity sensor and barometric pressure sensor are all arranged in the shell of the therapeutic instrument, the negative pressure sensor and vacuum pump are arranged inside the therapeutic instrument, and the drainage bottle is arranged outside the therapeutic instrument through a drainage bottle support.

3. The negative pressure wound therapy apparatus of claim 1, wherein, The human-computer interaction module further comprises a cloud applet, the main control PCB circuit board is provided with a WiFi module, and the main control chip is connected to and controls the WiFi module to connect to the cloud applet through the Internet of Things.

4. The negative pressure wound therapy apparatus of claim 1, wherein, The human-computer interaction module further comprises a host computer, and the main control chip is connected to the host computer through a USB serial port.

5. The negative pressure wound therapy apparatus of claim 1, wherein, Further comprising an alarm module comprising an alarm indicator arranged in the shell of the therapeutic instrument and a buzzer module arranged on the main control PCB circuit board, the main control chip receives the monitoring result of the liquid level monitor, controls the alarm indicator and buzzer module to alarm when the liquid level in the drainage bottle exceeds the threshold value, and converts the working state of the therapeutic instrument to pause, and the alarm indicator also displays the state signal of the current working state.

6. The negative pressure wound therapy apparatus of claim 1, wherein, Further comprising a touch key arranged on the shell of the therapeutic instrument and connected to the main control PCB circuit board for controlling the start, pause, stop and emergency brake of the instrument.

7. The negative pressure wound therapy apparatus of claim 6, wherein the valve is a duckbill valve. The control priority of the touch key is higher than that of the human-computer interaction module.

8. The negative pressure wound therapy apparatus of claim 1, wherein, The therapeutic instrument is provided with a UPS uninterruptible power supply for power supply, and the shell of the therapeutic instrument is provided with a charging interface of the UPS uninterruptible power supply.

9. The negative pressure wound therapy apparatus of claim 1, wherein, The display screen is an ink screen for displaying the working state of the therapeutic instrument and the environmental parameters, including but not limited to real-time time, real-time temperature and humidity, real-time barometric pressure, WiFi state, and the current working state and treatment remaining time of the therapeutic instrument.

10. The negative pressure wound therapy apparatus of claim 1, wherein, The operation interface displayed on the touch screen comprises SCREEN interface, SET interface and MODE interface which can be switched with each other, The SCREEN interface is used to display the current time and the environment temperature, humidity and air pressure read by the system, and is provided with touch hot areas for starting, pausing and ending the working state of the therapeutic instrument; The SET interface is used to select the working mode, turn on / off the WiFi, switch on / off the voice prompt and set the automatic sleep time of the therapeutic instrument; The MODE interface is used to set the treatment parameters in each working mode, including but not limited to the treatment time, maximum negative pressure value, minimum negative pressure value, peak-to-trough alternating time and peak-to-trough ratio.

11. The negative pressure wound therapy apparatus of claim 1, wherein, The working modes of the therapeutic instrument comprise peak-to-trough mode, user-defined mode and automatic mode, The target negative pressure value of the peak-to-trough mode is alternately set between the peak negative pressure value and the trough negative pressure value, wherein the peak-to-trough alternating time and the peak-to-trough ratio coefficient can be adjusted through the human-computer interaction module; The target negative pressure value of the user-defined mode is freely set by the user; The target negative pressure value of the automatic mode is randomly selected between the maximum negative pressure value and the minimum negative pressure value set by the user.

12. The negative pressure wound therapy apparatus of Claim 1, wherein, The calculation formula of the negative pressure normalization ratio coefficient is as follows: ； wherein, is the current negative pressure value of the therapy device, is the set target negative pressure value, is the negative pressure normalization proportionality factor.

13. The negative pressure wound therapy apparatus of Claim 1, wherein, The fitting function for fitting the PWM duty cycle coefficient is as follows: ； wherein, is a negative pressure normalization proportionality coefficient, is a PWM duty cycle coefficient.

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