Ventilation pipe and air purification system provided with same

Abstract

The invention relates to a breather pipe for an air purification system, comprising: an inlet end to be in airtight connection with an air outlet of a powered air purification respirator in the air purification system; the outlet end is opposite to the inlet end and is in airtight connection with a breathing mask in the air purification system; an audio acquisition module, a controller and an audio playing module are arranged in the vent pipe, and the controller is respectively in electric connection and data communication connection with the audio acquisition module and the audio playing module; wherein the audio acquisition module is used for acquiring an analog audio signal from the power air purification respirator and converting the analog audio signal into a digital audio signal; the controller receives the digital audio signal from the audio acquisition module and processes the digital audio signal to obtain a processed digital audio signal; and the audio playing module receives the processed digital audio signal from the controller and converts the digital audio signal into a processed analog audio signal for playing. The invention further relates to an air purification system provided with the breather pipe.

Description

Technical Field

[0001] The present invention generally relates to the technical field of powered air-purifying respirators (PAPRs), and particularly relates to an air duct capable of suppressing or even eliminating pneumatic noise and enhancing a prompting sound, which is used in an air purification system, and an air purification system equipped with the air duct. Background Art

[0002] A powered air-purifying respirator is an important component of an air purification system that ensures the normal work or healthy survival of an operator in an environment with pollution. The air purification system generally includes a breathing mask worn on a person's head and covering the face, a powered air-purifying respirator worn on the waist, for example, and an air duct that fluidly connects the two. The breathing mask can be, for example, a welding mask used in welding working conditions, a medical mask used in a healthcare environment (such as a place with airborne diseases), and so on. During operation, ambient air is inhaled into the respirator under the action of the power impeller of the powered air-purifying respirator, filtered by the air filtration unit, and then input to the breathing mask through the air duct for the user to inhale.

[0003] During the operation of a powered air-purifying respirator, various noises will be generated. Currently, the main noise sources are divided into: mechanical noise, electromagnetic noise, and BPF (blade passing frequency) pneumatic noise. Among them, the mechanical noise is mainly generated by mechanical friction of the motor's ball bearings, etc., and is low-frequency noise; the electronic noise is mainly related to the switching frequency of the motor drive; and the BPF pneumatic noise is mainly generated by the relative movement between the volute and the motor impeller, generally an integer multiple frequency of the impeller, and has a certain order characteristic. The pneumatic noise is also the main noise source of the PAPR device for the user.

[0004] On the other hand, as a protection device for an operator working in a polluted environment, the powered air-purifying respirator will also emit different prompting sounds or warning sounds to the operator under specific working conditions. Therefore, how to effectively eliminate the above-mentioned pneumatic noise, which is the main noise source, and enhance the prompting sound or warning sound transmitted from the main unit of the powered air-purifying respirator is an urgent problem to be solved in this technical field.

[0005] It should be noted that the "Background Art" paragraph is only used to help understand the content of the present invention. Therefore, the content disclosed in the "Background Art" paragraph may include some content that does not constitute the prior art known to those skilled in the art. The content disclosed in the "Background Art" paragraph does not represent the problems to be solved by this content or one or more embodiments of the present invention, which have been known or recognized by those skilled in the art before the filing of the present invention application. SUMMARY OF THE INVENTION

[0006] In view of the above defects in the prior art, it is necessary to provide a new type of ventilation pipe, which can be used to suppress or even eliminate the noise, especially pneumatic noise, transmitted from the main body of the powered air-purifying respirator to the operator's ear through pressurized air, and at the same time can enhance the prompt sound or warning sound transmitted from the main body.

[0007] To achieve the above object, the present invention provides a ventilation pipe for an air purification system, comprising:

[0008] An inlet end, which is to be hermetically connected to the air outlet of the powered air-purifying respirator in the air purification system; and an outlet end, which is opposite to the inlet end and is to be hermetically connected to the breathing mask in the air purification system; and

[0009] An audio acquisition module, a controller and an audio playback module are arranged in the ventilation pipe, and the controller is electrically connected and data communicatively connected to the audio acquisition module and the audio playback module respectively;

[0010] Wherein the audio acquisition module is used to acquire the analog audio signal from the powered air-purifying respirator and convert it into a digital audio signal;

[0011] The controller receives the digital audio signal from the audio acquisition module and processes it to obtain a processed digital audio signal;

[0012] The audio playback module receives the processed digital audio signal from the controller and converts it into a processed analog audio signal for playback.

[0013] Preferably, the controller includes a flash memory, and the flash memory pre-stores the pneumatic noise feature sequences of the powered air-purifying respirator at different air volume gears and the prompt sound feature sequences of the powered air-purifying respirator obtained through experimental acquisition and processing.

[0014] Preferably, the controller further includes a feature extraction module, which is used to extract the digital analog signal from the audio acquisition module in real time to obtain separated audio signals and their feature sequences. The separated audio signals include pneumatic noise signals and, when there is a prompt sound, also include prompt sound signals. The feature sequences of the separated audio signals include the real-time pneumatic noise feature sequences and the real-time prompt sound feature sequences at the current air volume gear.

[0015] Preferably, the controller is configured to compare the characteristic sequence of the separated audio signal with the pneumatic noise characteristic sequence and the prompt tone characteristic sequence pre-stored in the flash memory in terms of similarity, and based on the highest similarity obtained from the comparison, emit an inverted wave of the pneumatic noise characteristic sequence corresponding to the current air volume gear, and in the case of the presence of a prompt tone, perform gain on the prompt tone characteristic sequence, wherein the pneumatic noise signal is superimposed with the inverted wave and the prompt tone signal is superimposed with the gain-adjusted prompt tone characteristic sequence, and the above two superimposed results are mixed to obtain the processed digital audio signal.

[0016] Preferably, the similarity comparison is performed based on the comparison of the following items between different feature vectors of each characteristic sequence, and the items include any one or more of cosine similarity, norm, Euclidean distance, Manhattan distance, and Mahalanobis distance.

[0017] Preferably, the audio acquisition module is disposed in the ventilation pipe near the inlet end, and includes a microphone oriented towards the air outlet of the powered air purification respirator, and the microphone is used to acquire the analog audio signal from the powered air purification respirator.

[0018] Preferably, the audio acquisition module further includes a programmable gain amplifier and an analog-to-digital converter, and the programmable gain amplifier is used to amplify the analog audio signal acquired by the microphone and further convert it into the digital audio signal via the analog-to-digital converter.

[0019] Preferably, the audio playback module includes a digital-to-analog converter, a linear amplifier, and a speaker, wherein the digital-to-analog converter converts the processed digital audio signal from the controller into the processed analog audio signal, and the linear amplifier amplifies the processed analog audio signal to be played towards the inlet end of the ventilation pipe via the speaker, and the linear amplifier is controlled by a linear knob disposed at the outlet end of the ventilation pipe.

[0020] Preferably, the audio playback module further includes an additional speaker, and the additional speaker is disposed in the ventilation pipe in the direction towards the outlet end, and is configured to directly play an enhanced prompt tone towards the outlet end when the digital audio signal acquired and converted by the audio acquisition module is extracted as a prompt tone signal by the feature extraction module of the controller.

[0021] Preferably, the ventilation pipe further includes an integrated cable for electrically connecting and data communicating the controller with the audio acquisition module and the audio playback module respectively, and the cable is disposed attached to the outer wall of the ventilation pipe or disposed inside the hollow of the ventilation pipe, so that the wiring of the cable can conform to the flexible arrangement of the ventilation pipe.

[0022] Preferably, the ventilation pipe further includes a power supply port connected to the cable. When the inlet end of the ventilation pipe is hermetically connected to the air outlet of the powered air purification respirator, the power supply port can be electrically connected to an electrical connection component provided at the air outlet of the powered air purification respirator, so that the power from the power supply of the powered air purification respirator can be transmitted via the cable to supply power to the audio acquisition module, the controller, and the audio playback module.

[0023] According to another aspect of the present invention, there is provided an air purification system, characterized by comprising a powered air purification respirator, a breathing mask, and the ventilation pipe according to the foregoing invention content, wherein the inlet end of the ventilation pipe is hermetically connected to the air outlet of the powered air purification respirator, and the outlet end of the ventilation pipe is hermetically connected to the breathing mask. Brief Description of the Drawings

[0024] The following will more thoroughly understand and recognize the above and other aspects of the present invention in conjunction with the drawings, wherein:

[0025] Figure 1 shows a schematic external view of the air purification system according to the present invention;

[0026] Figure 2 shows in the Figure 1 schematic diagram of the ventilation pipe used in the air purification system shown;

[0027] Figure 3 shows Figure 2 the operating principle diagram of the ventilation pipe in

[0028] Figure 4 for suppressing / eliminating pneumatic noise and enhancing the prompt tone or warning tone in the form of an analog signal; Detailed Description of the Embodiments

[0029] In order to make the technical problems to be solved, technical solutions, and beneficial technical effects of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with the drawings and exemplary embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the protection scope of the present invention. Unless otherwise clearly stated in the drawings, the dimensions, positions, etc. of each component, feature, element, etc., and any distance between them are not necessarily drawn to scale, and may be out of proportion and / or exaggerated for clarity.

[0030] The terms used herein are for the purpose of describing particular exemplary embodiments only and are not intended to be limiting. As used herein, unless the context clearly dictates otherwise, the singular forms "a," "an," and "the" are intended to include the plural forms as well. It should be recognized that the terms "comprising," "including," and / or "consisting of," when used in this specification, specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof. Unless otherwise indicated, when listing a range of values, the upper and lower limits of the range, as well as any sub-ranges therebetween, are included. Unless otherwise stated, terms such as "first," "second," etc., are used only to distinguish one element from another. For example, one element may be referred to as "a first element," and similarly, another element may be referred to as "a second element," and vice versa. The paragraph headings used herein are for organizational purposes only and should not be construed as limiting the subject matter described.

[0031] Unless expressly indicated otherwise, the terms "about," "approximately," "substantially," etc. mean that the quantity, dimension, formulation, parameter, and other quantities and characteristics are not and need not be exact, but may be approximate and / or larger or smaller as desired.

[0032] Unless expressly indicated otherwise, all connections and all operative connections may be direct or indirect. Similarly, unless expressly indicated otherwise, all connections and all operative connections may be rigid or non-rigid. Additionally, in the present invention, the term "connected / coupled" includes not only mechanical connections, but also electrical connections and communicatively coupled connections between components and / or units / modules with each other.

[0033] Like reference numerals throughout the text refer to like elements. Thus, the same or similar reference numerals may be described with reference to other figures, even if they are neither mentioned nor described in the corresponding figures. Moreover, even elements that are not marked with reference numerals may be described with reference to other figures.

[0034] Figure 1The schematic external view of the air purification system according to the present invention is shown. The air purification system includes a breathing mask 100 for wearing on the head of an operator, a powered air purifying respirator 200 for wearing on the body of the operator (such as around the waist), and an air pipe 300 that is airtight connected between the breathing mask 100 and the powered air purifying respirator 200. Those skilled in the art can understand that, in the context of the present invention, the above-mentioned breathing mask 100 can be a welding mask used in welding working conditions, a medical mask used in a healthcare environment (such as in a situation where there is an airborne disease), or a corresponding mask adopted in other application fields with high demand for air purification.

[0035] As shown in the figure, the powered air purifying respirator 200 includes a housing, and components such as an air filter cartridge (not shown), a power source (such as a rechargeable battery), a control circuit board, and a fan 220 are provided inside the housing. In addition, an internal air duct (not shown) is constructed inside the housing, such that the air filter cartridge is located at the inlet of the internal air duct and the fan 220 is located in the internal air duct, and the outlet of the internal air duct can be used as the air outlet 210 of the powered air purifying respirator 200 and is airtight connected to the above-mentioned air pipe 300. The power source can controllably supply power to the fan 220. Corresponding electronic components are provided on the control circuit board for monitoring data related to the real-time air volume; and / or for connecting to the data interface of the air filter cartridge itself to read relevant parameter data, such as the usage time and usage times of the air filter cartridge; and / or for monitoring the real-time power of the rechargeable battery serving as the power source, etc. During the operation of the entire air purification system, the fan 220 in the powered air purifying respirator 200 is turned on under the control of the control circuit board, sucks outside air into the air filter cartridge through the air inlet of the housing, and discharges the filtered air from the air outlet 210 into the air pipe 300 and further transmits it to the inside of the breathing mask 100 for the operator to inhale. As mentioned above, the relative movement between the volute and the impeller of the fan 220 will generate significant pneumatic noise, and this part of the pneumatic noise will also be transmitted from the noise source of the fan 220 to the ear-wearing part of the breathing mask 100 through the air pipe 300, thereby reducing the comfort of the operator. In addition, a buzzer alarm and / or a vibrator are usually provided in the powered air purifying respirator 200 to emit a prompt sound or an alarm sound under specific working conditions (such as when the air filter cartridge reaches the usage period or the number of times and needs to be replaced, the air volume is insufficient, the power is insufficient, etc.), and this part of the audio will also be transmitted to the ear-wearing part of the breathing mask 100 through the air pipe 300. Different from the pneumatic noise, the above-mentioned prompt sound or alarm sound needs to be enhanced to ensure that the operator can be reminded in a noisy construction environment.

[0036] The object of the present invention is achieved by Figure 2It is realized by a new type of intelligent ventilation tube 300 used in combination with a powered air-purifying respirator and a breathing mask. As shown in the figure, an audio acquisition module 301, a controller 302, and an audio playback module 303 are provided in the ventilation tube. The controller 302 is electrically connected and data communicatively connected to the audio acquisition module 301 and the audio playback module 303 respectively. For clarity, the above components are schematically shown outside the ventilation tube in Figure 2 and the set positions are only exemplary and non-limiting in the figure. Preferably, the audio acquisition module 301 is provided at an inlet end 310 of the ventilation tube 300 to be connected to the powered air-purifying respirator, while the controller 302 and the audio playback module 303 are provided at another outlet end 320 of the ventilation tube 300 to be connected to the breathing mask, where the outlet end 320 is opposite to the inlet end 310. In addition, the ventilation tube 300 is integrated with a cable 330 to achieve power supply and data communication connections between the audio acquisition module 301, the controller 302, and the audio playback module 303. In practice, the power supply (such as a rechargeable battery) of the powered air-purifying respirator can directly or after being connected to an external power supply to provide electrical energy for the above-mentioned hardware. Further, the audio acquisition module 301 is used to acquire an analog audio signal from the powered air-purifying respirator at the inlet of the ventilation tube and convert it into a digital audio signal, and send the digital audio signal to the controller 302. It can be understood that depending on the operating state of the powered air-purifying respirator, the analog audio signal at the inlet of the ventilation tube includes a noise signal mainly composed of pneumatic noise, and additionally includes an audio signal representing a prompt tone or an alarm tone under specific working conditions. The controller 302 receives the digital audio signal from the audio acquisition module 301 and processes it to generate a processed digital audio signal that is the inverse of the pneumatic noise and / or has a gain for the prompt tone, and sends the processed digital audio signal to the audio playback module 303. Further, the audio playback module 303 receives the processed digital audio signal and converts it into a processed analog audio signal for playback. The processed analog audio signal cancels out the pneumatic noise signal on the one hand due to the opposite phase and the same amplitude, and on the other hand increases the gain of the prompt tone to effectively compensate for the loss of the prompt tone during transmission in the ventilation tube. Those skilled in the art can understand that the audio acquisition module 301 may include an audio acquisition device in the form of a microphone, a pickup, a piezoelectric ceramic sheet, etc., and also integrates a programmable gain amplifier PGA and an analog-to-digital converter ADC for preprocessing the analog audio signal (see Figure 3 ). Among them, Figure 2 the audio acquisition module 301 is shown by taking a directional microphone as an example. It is located at the connection interface of the ventilation tube and the powered air-purifying respirator and faces the main air outlet of the powered air-purifying respirator to acquire the analog audio signal emitted from the air outlet of the powered air-purifying respirator.

[0037] The following refers toFigure 3 The principle of the present invention is explained and illustrated as follows. As shown in the figure, first, the differential analog audio signal Sound collected by the directional microphone is input input to the programmable gain amplifier PGA. The PGA is used to adjust and amplify the analog audio signal (which is in the form of a continuous voltage analog signal), so that the full-scale signal of the subsequent analog-to-digital converter ADC can be equalized, thereby improving the measurement accuracy. The amplified analog audio signal is further input to the ADC to be converted into a digital audio signal, and the digital audio signal is communicated to the controller 302 for subsequent processing. The controller 302 includes a feature extraction module 3021, which is used to perform real-time feature extraction on the digital audio signal to obtain a separated audio signal and its feature sequence. Among them, the separated audio signal includes the pneumatic noise signal Sound noise and, in the presence of a prompt tone, also includes the prompt tone signal Sound use . The extracted features include, but are not limited to, the amplitude features and phase features of the initial spectrum obtained by performing a Fourier transform on the time-domain waveform of the audio signal, as well as the spectrogram features, FBank features, MFCC features, PLP features, etc. obtained based on the initial spectrum. On the other hand, the controller also includes a flash memory, in which the pneumatic noise feature sequence NOISE fs [m] and the prompt tone feature sequence USE fs [n] collected and processed through experiments are stored. In this article, the pneumatic noise feature sequence NOISE fs [m] includes m feature vectors S1, S2... S m , where m represents the number of air volume levels (for example, a total of 3 to 6 levels, and the specific number of levels can be selectively increased or decreased according to actual use). That is, NOISE fs [m] = [S1, S2... S m , where S1 represents the audio features extracted from the pneumatic noise audio signal at the first air volume level (i.e., the lowest air volume level) collected in the laboratory environment, and S m represents the audio features extracted from the pneumatic noise audio signal at the mth air volume level collected in the laboratory environment. On the other hand, the prompt tone feature sequence USE fs [n] includes n feature vectors W1, W2... W n , where n represents the number of operating states in which a prompt tone needs to be issued to the user during the operation of the powered air-purifying respirator. That is, USE fs [n] = [W1, W2... W n, where W1 is, for example, an audio feature obtained by extracting an audio signal of a prompt tone indicating that the air filter cartridge of the powered air-purifying respirator has reached its service life; W2 is, for example, an audio feature obtained by extracting an audio signal of a prompt tone indicating insufficient power of the powered air-purifying respirator; W n is, for example, an audio feature obtained by extracting an audio signal of a prompt tone indicating that a specific component of the powered air-purifying respirator has failed, and so on. During operation, the controller further compares the feature sequence of the separated audio signal extracted in real time by the feature extraction module with the pneumatic noise feature sequence NOISE fs [m] and the prompt tone feature sequence USE fs [n] stored in advance in the flash memory to read the pre-stored pneumatic noise features at the corresponding file air volume from the controller flash memory, and at the same time traverse USE fs [n] to determine whether there is a prompt tone. The above similarity comparison can be based on cosine similarity comparison, norm comparison known in the art, such as comparing the Euclidean distance, Manhattan distance, Mahalanobis distance, etc. between feature vectors, which will not be elaborated too much in this article.

[0038] Further, the controller inverts the pneumatic noise feature sequence in the real-time input sound source Sound input through an inverter, and amplifies the prompt tone feature sequence (if any) through an operational amplifier. Among them, the inverter includes not only hardware inverters, such as DTL type, TTL type, and CMOS inverters, etc., but can also be a signal phase inversion implemented through software algorithms (such as through programming languages, digital signal processing libraries, system-level logic control, etc.). Referring to Figure 3 , the pneumatic noise signal Sound noise extracted by the feature extraction module is superimposed with the inverted wave of NOISE fs [m] pre-stored in the flash memory, and the extracted prompt tone signal Sound use is superimposed with the amplified prompt tone feature sequence USE fs [n], and the two superimposed results are mixed by means of a mixer MIX to obtain a processed digital audio signal transmitted from the controller to the audio playback module. Referring to Figure 4 , which shows in the form of an analog signal the effect diagram of suppressing / eliminating pneumatic noise and enhancing the prompt tone or prompt tone according to the principle of the present invention. Among them, the first part I in the upper left corner shows the analog signal diagram of the pneumatic noise stripped by feature matching (see the solid waveform in the figure), and the white noise generated by the controller through the software inverter (see the dotted waveform in the figure), and the two are superimposed to obtain the analog signal diagram shown in the second part II in the upper right corner after effectively canceling the pneumatic noise. On the other hand, when the powered air-purifying respirator needs to emit a prompt tone to the user due to various abnormal operating conditions,Figure 4 The third part in the lower left corner shows the analog signal diagram of the prompting sound stripped through feature matching and the white noise of the prompting sound obtained through the controller gain. After the two are superimposed, the analog signal diagram of the gain prompting sound shown in the fourth part in the lower right corner is obtained. Through Figure 4 the second and fourth parts, it can be clearly seen that by operating the controller, the pneumatic noise is effectively suppressed and the prompting sound is enhanced. Next, further as Figure 3 shown, the digital audio signal obtained after being mixed by the mixer MIX is then converted into a processed analog audio signal by the digital-to-analog converter DAC in the audio playback module, and further drives the speaker SPK to play synchronously towards the input end of the ventilation pipe through the power amplifier. According to the superposition principle of sound waves, finally Figure 4 the suppression of pneumatic noise and the enhancement of the prompting sound shown in the analog signal diagrams of the second and fourth parts are transmitted into the breathing mask connected to the ventilation pipe. Using the technical solution of the embodiment shown in the present invention, not only the pneumatic noise transmitted into the breathing mask is effectively reduced, but also for the prompting sound, the loss of the prompting sound during transmission in the ventilation pipe is effectively compensated by means of gain, so as to facilitate reminding the user of the problems that occur during the operation of the powered air purifying respirator.

[0039] In addition to being able to achieve the functions of suppressing or eliminating pneumatic noise and increasing the gain of the prompting sound, combined with the description of the above embodiments, the technical concept of the present invention is to integrally arrange an audio acquisition module, a controller and an audio playback module in the ventilation pipe. In this way, the ventilation pipe can be modularly manufactured as a relatively independent whole. As long as the interface at the inlet end of the ventilation pipe is adapted to the air outlet of the powered air purifying respirator and the interface at the outlet end of the ventilation pipe is adapted to the input end of the breathing mask, then this modular ventilation pipe can be used in combination with powered air purifying respirators and breathing masks from different manufacturers without providing a complete air purification system. It can be understood that when the ventilation pipe and the powered air purifying respirator in the air purification system are manufactured by the same manufacturer, the aforementioned pneumatic noise feature sequence NOISE fs [m] and the prompting sound feature sequence USE fs [n] can be obtained through experimental acquisition and processing before leaving the factory and pre-stored in the flash memory of the controller. Optionally, when the powered air purifying respirators come from different manufacturers, after the entire air purification system is assembled and before it is officially enabled, an initialization operation can be performed to overwrite and replace the pneumatic noise feature sequence and the audio feature sequences representing various prompting sounds pre-stored in the flash memory of the controller with the pneumatic noise feature sequences at different air volume levels generated during the operation of the current powered air purifying respirator and the audio feature sequences representing various prompting sounds.

[0040] The present invention is not limited to the above specific structure, but can produce various variants.

[0041] For example, as can be seen in the Figure 2 illustrated embodiment, the audio acquisition module 301 is disposed near the inlet end 310 of the ventilation pipe 300 (i.e., the end connected to the air outlet of the powered air-purifying respirator), and the controller 302 and the audio playback module 303 are integrally disposed near the outlet end 320 of the ventilation pipe 300 (i.e., the end connected to the breathing mask). In this case, during practical operation, the pneumatic noise entering the ventilation pipe and the possible prompt sound can be sensed fastest. Although a certain degree of attenuation will occur during the relevant audio signal transmission process, this part of the attenuation can be compensated by software. In addition, the present invention is not limited to the above-described setting method. According to actual needs, the positions of the audio acquisition module, the controller, and the audio playback module in the ventilation pipe can be flexibly arranged. For example, the audio acquisition module can also be disposed together with the controller and the audio playback module near the outlet end of the ventilation pipe, so that the pneumatic noise to be discharged from the ventilation pipe can be collected while ignoring the attenuation during the transmission process caused by the length of the ventilation pipe. On the other hand, this also poses higher requirements on the "response" speed of the controller.

[0042] Optionally, in combination with Figure 2 and Figure 3 as shown, a linear amplifier LINE-AMP is also provided in the audio playback module 303 for amplifying the processed analog audio signal obtained by conversion by the digital-to-analog converter DAC and playing it via the speaker SPK. The linear amplifier LINE-AMP can be controlled by, for example, a linear knob 304 disposed at the outlet end of the ventilation pipe.

[0043] As described above, the ventilation pipe uses an integrated cable to achieve power supply and data communication connections between the audio acquisition module, the controller, and the audio playback module. Although Figure 2 it is schematically shown that the cable 330 is attached to the outer wall of the ventilation pipe 300, it can be understood that the cable 330 can also be disposed inside the hollow of the ventilation pipe 300, especially at least partially fixed or adhered to the inner wall of the ventilation pipe, so that the wiring of the cable can conform to the flexible arrangement of the ventilation pipe. The ventilation pipe of the present invention is also provided with a power supply port, and the form of the power supply port can be a pogopin or a type-c. When the inlet end of the ventilation pipe is hermetically connected to the air outlet of the powered air-purifying respirator, the power supply port of the ventilation pipe can be electrically connected to an electrical connection component (such as a male or female cable plug, a conductive bump, or a male or female end of a type-c) disposed on the inner wall or near the air outlet of the powered air-purifying respirator. Thus, the power from the power source of the powered air-purifying respirator (such as an external power source or a rechargeable battery) can be transmitted via the cable to supply power to the audio acquisition module, the controller, and the audio playback module integrated in the ventilation pipe.

[0044] Further, the air volume gear at which the powered air-purifying respirator is currently operating can be obtained through the data bus in the above cable and transmitted to the controller. The controller can read the pre-stored pneumatic noise feature sequence from the flash memory based on the air volume gear for matching, so as to emit an inverted wave of the pneumatic noise feature sequence corresponding to the current air volume gear. In this way, the above-mentioned similarity comparison process can be simplified.

[0045] In addition, the audio playback module may include an additional speaker, which is arranged in the ventilation pipe in the direction of the outlet end (i.e., the direction towards the connection with the breathing mask). In this case, when the digital audio signal collected and converted by the audio collection module is extracted by the feature extraction module of the controller to obtain the audio feature sequence related to the prompt sound, the enhanced prompt sound can be directly played towards the breathing mask through this additional speaker. In this way, the prompt sound can be decoupled from the pneumatic noise.

[0046] Correspondingly, the assembly and operation process of the air purification system equipped with the above ventilation pipe are as follows:

[0047] First, provide the aforementioned modular ventilation pipe, the breathing mask and the powered air-purifying respirator to be used in combination with it; second, airtightly connect the inlet end of the ventilation pipe to the air outlet of the powered air-purifying respirator adapted to it, and airtightly connect the outlet end of the ventilation pipe to the input end of the breathing mask adapted to it. At the same time, the power supply port of the ventilation pipe is electrically connected to the electrical connection component arranged on the inner wall or near the air outlet of the powered air-purifying respirator so as to obtain power from the powered air-purifying respirator; third, depending on whether the ventilation pipe and the breathing mask are manufactured by the same manufacturer, selectively perform an initialization operation on the ventilation pipe to obtain the pneumatic noise feature sequence and the prompt sound feature sequence for the powered air-purifying respirator; finally, in actual operation, the audio collection module, the controller and the audio playback module integrated in the ventilation pipe perform the corresponding functions as described above (in combination Figure 3 with the description) to suppress / eliminate the pneumatic noise propagating in the ventilation pipe and additionally enhance the prompt sound / alarm sound.

[0048] The feasible but non-limiting embodiments of the vent pipe according to the present invention and the air purification system equipped with the vent pipe have been described in detail with reference to the accompanying drawings. For those of ordinary skill in the art, modifications and supplements to the technology and structure, as well as the recombination of features in each embodiment, should be regarded as being included within the scope of the present invention without departing from the scope and essence of the present disclosure set forth in the following claims. Therefore, these modifications and supplements that can be conceived under the teachings of the present invention should be regarded as a part of the present disclosure. The scope of the present disclosure is defined by the following appended claims and includes equivalent technologies known at the filing date of the present disclosure application and equivalent technologies not yet foreseen.

Claims

1. An air pipe for an air purification system, comprising: An inlet end, which is to be hermetically connected to the air outlet of the power air purification respirator in the air purification system; And an outlet end, which is opposite to the inlet end and is to be hermetically connected to the breathing mask in the air purification system; and An audio acquisition module, a controller and an audio playback module are arranged in the air pipe, and the controller is electrically connected and data communicatively connected to the audio acquisition module and the audio playback module respectively; Wherein the audio acquisition module is used to acquire the analog audio signal from the power air purification respirator and convert it into a digital audio signal; The controller receives the digital audio signal from the audio acquisition module and processes it to obtain the processed digital audio signal; The audio playback module receives the processed digital audio signal from the controller and converts it into a processed analog audio signal for playback.

2. The vent pipe according to claim 1, wherein The controller includes a flash memory, and the pneumatic noise feature sequence of the power air purification respirator and the prompt tone feature sequence of the power air purification respirator obtained through experimental acquisition and processing are pre-stored in the flash memory.

3. The vent pipe according to claim 2, wherein, The controller further includes a feature extraction module, and the feature extraction module is used to extract the digital analog signal from the audio acquisition module in real time to obtain the separated audio signal and its feature sequence. The separated audio signal includes a pneumatic noise signal and, when there is a prompt tone, also includes a prompt tone signal. The feature sequence of the separated audio signal includes the real-time pneumatic noise feature sequence and the real-time prompt tone feature sequence at the current air volume level.

4. The vent pipe according to claim 3, wherein, The controller is configured to compare the feature sequence of the separated audio signal with the pneumatic noise feature sequence and the prompt tone feature sequence pre-stored in the flash memory for similarity, and based on the highest similarity obtained from the comparison, emit the inverse wave of the pneumatic noise feature sequence corresponding to the current air volume level, and when there is a prompt tone, perform gain on the prompt tone feature sequence, wherein the pneumatic noise signal is superimposed with the inverse wave and the prompt tone signal is superimposed with the gain-adjusted prompt tone feature sequence, and the above two superimposed results are mixed to obtain the processed digital audio signal.

5. The vent pipe according to claim 4, characterized in that, The similarity comparison is performed based on the comparison of the following items among the different feature vectors of each feature sequence, and the items include any one or more of cosine similarity, norm, Euclidean distance, Manhattan distance, and Mahalanobis distance.

6. The vent pipe according to any one of claims 1 to 5, characterized in that, The audio acquisition module is arranged in the air pipe close to the inlet end, and includes a microphone arranged in a direction facing the air outlet of the power air purification respirator, and the microphone is used to acquire the analog audio signal from the power air purification respirator.

7. The vent pipe according to claim 6, characterized in that, The audio acquisition module further includes a programmable gain amplifier and an analog-to-digital converter, and the programmable gain amplifier is used to amplify the analog audio signal acquired by the microphone and further convert it into the digital audio signal through the analog-to-digital converter.

8. The vent pipe according to any one of claims 1 to 5, characterized in that, The audio playback module includes a digital-to-analog converter, a linear amplifier, and a speaker. The digital-to-analog converter converts the processed digital audio signal from the controller into the processed analog audio signal. The linear amplifier amplifies the processed analog audio signal to be played via the speaker toward the inlet end of the ventilation tube. The linear amplifier is controlled by a linear knob provided at the outlet end of the ventilation tube.

9. The vent pipe according to claim 8, characterized in that, The audio playback module further includes an additional speaker. The additional speaker is arranged in the ventilation tube in the direction toward the outlet end and is configured to directly play an enhanced prompt sound toward the outlet end when the digital audio signal collected and converted by the audio collection module is extracted by the feature extraction module of the controller to obtain a prompt sound signal.

10. The vent pipe according to any one of claims 1 to 5, characterized in that, It further includes an integrated cable for electrically connecting and data communicating the controller with the audio collection module and the audio playback module respectively. The cable is arranged attached to the outer wall of the ventilation tube or inside the hollow of the ventilation tube so that the wiring of the cable can conform to the flexible arrangement of the ventilation tube.

11. The vent pipe according to claim 10, characterized in that, It further includes a power supply port connected to the cable. When the inlet end of the ventilation tube is airtightly connected to the air outlet of the powered air-purifying respirator, the power supply port can be electrically connected to the electrical connection component provided at the air outlet of the powered air-purifying respirator, so that the power from the power supply of the powered air-purifying respirator can be transmitted via the cable to supply power to the audio collection module, the controller, and the audio playback module.

12. An air purification system, characterized in that, It includes a powered air-purifying respirator, a breathing mask, and the ventilation tube according to any one of claims 1 to 11, wherein the inlet end of the ventilation tube is airtightly connected to the air outlet of the powered air-purifying respirator, and the outlet end of the ventilation tube is airtightly connected to the breathing mask.

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