CN203169862U - Positive pressure air supply semi-open type air-purifying helmet mask - Google Patents

Abstract

The utility model discloses a semi-open air-purifying helmet mask with positive pressure air supply, which comprises a helmet, a mask, a power device, an air filter device, and an air pressure and voltage alarm device. The lower extension cover is outside the face of the human body, and there is a gap between the mask and the face of the human body; the power device includes a fan and a power supply; Inside, the two ends of the plenum box are the air inlet and outlet respectively; the front edge of the helmet is provided with a downward blowing port; the fan and air filter in the power unit are respectively arranged in the middle of the plenum On the air side, the air filter device is a filter using electret air filter material as the filter element. The helmet mask of the utility model has the functions of preventing dust and exhaust gas and preventing bacteria and viruses at the same time, and does not need to drag any external pipeline equipment, has a simple structure, is easy to wear, and breathes smoothly and comfortably.

Description

A semi-open air-purifying helmet mask with positive pressure air supply

technical field

The utility model relates to a helmet mask, in particular to a positive-pressure air-supply semi-open air-purifying helmet mask.

Background technique

With the occurrence and prevalence of respiratory diseases such as SARS and bird flu, as well as the increasingly serious pollution of dust and exhaust gas in the atmospheric environment, people are increasingly aware of the importance of respiratory protection and respiratory health, and respiratory protective equipment is receiving more and more attention. more attention. However, although the relevant respiratory protective equipment has been developed for nearly a century, it is still difficult to enter people's daily life, and it is even difficult to play a role in preventing epidemics. The reason is that the current respiratory protective equipment has the following shortcomings and problems:

1. Whether it is the simplest mask or a complex gas mask, they are basically sealed, which greatly affects the comfort of breathing;

2. The protection effect of general products is not good, and the self-priming filter structure is usually used, which has poor air tightness and safety. It can only prevent part of the dust and cannot protect against bacteria, viruses or exhaust gas pollution. The isolated equipment that can protect against bacterial viruses or exhaust gas pollution is usually bulky, heavy and complicated, expensive, and must be dragged with compressed gas cylinders and long tubes for conveying purified air, which is very inconvenient to wear, use and move.

3. Recently, the power air-supply air-purifying mask that has appeared recently also needs to wear complicated parts such as air-supply fan, breathing tube and driving power supply on the body, and most of them can only prevent dust and cannot protect against relevant viruses and bacteria.

For this reason, people need a new type of air purification equipment, which should have the protective functions of dust prevention and protection against bacterial viruses or exhaust gas pollution, which are only available in large respiratory protective equipment in the past, and it is light, convenient, affordable, and beautiful in appearance. , breathing comfortably and smoothly. It is not only suitable for medical personnel, traffic police and road administrators who work in highly infectious or high dust exhaust environment all the year round, but also can be used by ordinary people for breathing safety.

Utility model content

The purpose of this utility model is to overcome the deficiencies of the prior art and provide a semi-open air purification helmet mask with positive pressure air supply. Function, and simple structure, light and beautiful, easy to wear, smooth and comfortable breathing.

The technical scheme that the utility model realizes above-mentioned purpose is:

A semi-open air-purifying helmet mask with positive pressure air supply, including a helmet, a mask, a power unit, an air filter device, and an air pressure and voltage alarm device, wherein the mask is arranged on the front of the helmet, and the mask body extends downward Outside the face of the human body, there is a gap between the mask and the face of the human body; the power device includes a fan and a power supply; it is characterized in that:

It also includes a static pressure box, the static pressure box, the power unit, the air filter device and the air pressure and voltage alarm device are all arranged in the helmet, wherein the two ends of the static pressure box are respectively the air inlet end and the air outlet end, wherein the air outlet end is located at the front of the helmet; the front edge of the helmet is provided with a downward blowing port, which communicates with the air outlet end of the static pressure box;

The fan and the air filter in the power unit are arranged at the middle part and the air inlet end of the plenum box respectively, wherein the air filter is a filter using electret air filter material as a filter element.

A preferred solution of the present utility model, wherein, the helmet is a double-layer structure composed of an outer helmet shell and an inner helmet shell, and a sandwich space is formed between the outer helmet shell and the inner helmet shell, and the gap is 15-25mm , the static pressure box, the power unit, the air filtering device and the air pressure and voltage alarm device are all arranged in the interlayer space. The entire helmet visor does not drag any external pipes, wires or other external devices, and only one power charging socket is left for charging the power supply.

In a preferred solution of the present utility model, the static pressure tank is an arc-shaped channel with a smooth inner surface, and the arc-shaped channel extends from the rear of the helmet across the top of the helmet to the front of the helmet.

A preferred solution of the present utility model, wherein, the air outlet is an arc-shaped opening arranged along the front edge of the helmet.

In a preferred solution of the present invention, the length of the arc-shaped opening is slightly longer than the length from the outer edge of the wearer's left eye to the outer edge of the right eye.

In a preferred solution of the present utility model, wherein, the mask is a cover body made of anti-fogging highly transparent PVC with a smooth arc-shaped face, and the mask is combined with the helmet to provide the wearer with Curtain-shaped positive pressure purification airflow drainage channels from the forehead down to the chin and covering the outer corners of the eyes and the cheeks.

A preferred solution of the present utility model, wherein, the length of the static pressure tank is 80-125 mm, and the cross-sectional area thereof is 256-976 mm ² . The wind speed of the wind blown out from the blowing port is 0.28m/s-0.31m/s, and forms a curtain-shaped wind belt with a range greater than 15cm.

A preferred solution of the present utility model, wherein, the electret air filter material is an electret electrostatic synthetic fiber filter material.

In a preferred solution of the present utility model, wherein the air pressure and voltage alarm device includes a pressure sensing system and a voltage sensing system, wherein the pressure sensing system includes a pressure sensor for detecting the air pressure in the static pressure box and when filtering A pressure early warning circuit that sends an alarm when the required working resistance of the device is too large; the voltage sensor system includes a voltage detection and early warning circuit that is used to detect the voltage of the power supply and sends an alarm when the voltage is too low; the pressure early warning circuit includes sequentially connected A reference power supply, an inverter, a multivibrator and a buzzer; the voltage detection and warning circuit includes a sequentially connected sampling circuit, an inverter, a multivibrator and a buzzer.

A preferred solution of the present utility model, wherein the power supply is a rechargeable micro-lithium battery pack with an output voltage of 10V and a capacity ≥ 2700mAh, and the fan has an air volume range of 13CFM to 20CFM and a power consumption current of no more than 280mA low power fans.

The working principle of the utility model is: after the fan works, the air is driven to flow, and under the pressurization of the static pressure box, a sufficient pressure difference is established on both sides of the filter, so that the air can pass through the electret with better filtering performance. The air filter material is used as the filter of the filter element. When the air passes through the filter, the dust particles in the air and the bacteria and viruses attached to them are filtered out due to electrostatic adsorption; Delivered downward for the user to breathe, the wind speed is large enough to generate sufficient positive pressure in the space between the mask and the user's face, preventing external air from passing through the gap between the user's face and the edge of the mask However, the wind speed will not be so great that the user feels uncomfortable, usually 0.28m/s ~ 0.31m/s, and the range is greater than 15cm, so as to reach the wearer's chin and cover all the wearer's breathing-related organs (mouth , nose, eyes); so that the wearer can only breathe the purified air provided by it, and not let the externally polluted air enter, so as to achieve the effect of not only filtering out bacteria and viruses but also removing dust and exhaust gas.

The design and the work of several parts of the utility model cooperate with each other and are closely linked. First choose the electret air filter material as the filter of the filter element to ensure that dust exhaust gas and bacteria and viruses can be filtered efficiently; but even those skilled in the art know that the filter using the electret air filter material as the filter element can simultaneously filter dust and Bacteria and viruses, because the air-tightness of the electret air filter material is better, it is necessary to provide a large enough pressure difference to allow the air to pass through it, and if this filter is to be applied to the helmet mask, it needs to be installed on the user's face. In addition, wearing high-power powerful air blower, breathing tube, driving power and other complicated parts on the body will inevitably lead to complex structure and inconvenient use; and the utility model is provided with a static pressure box in the helmet, through which the utility model can The new type can also obtain enough wind pressure to pass through the filter when using a miniature low-power fan, and can still maintain a wind speed of 0.28m/s to 0.31m/s after passing through the filter. And just because of adopting miniature low power consumption fan, just make the utility model can adopt miniature battery to keep up to 8 hours power supply and work normally, also just can make all these parts all can be placed in the helmet, and need not involve other The utility model not only has the function of preventing dust and waste gas and preventing bacteria and viruses, but also simplifies the structure and is quite convenient to use.

Compared with the prior art, the utility model has the following beneficial effects:

1. The utility model has the functions of preventing dust, exhaust gas and bacteria and viruses at the same time, and all components are arranged in the helmet, without connecting complicated external devices, and without dragging any external pipeline equipment. It is not only simple in appearance, but also very convenient to use. In the prior art, only large-scale respiratory protective devices that are bulky, heavy and complicated, expensive and inconvenient to use have the functions of preventing dust and preventing bacteria and viruses.

2. The utility model is a semi-open helmet mask with positive pressure air supply, which actively sends filtered fresh air to the user's mouth and nose, and the user does not need to cover the mouth and nose, and can breathe naturally and smoothly, with high comfort Greatly enhanced, especially the air outlet is an arc-shaped opening set along the front edge of the helmet, blowing the purified air downward at a wind speed of 0.28m/s~0.31m/s, forming a curtain-like wind with a range of >15cm The belt makes the airflow even, comfortable and better.

3. It can use miniature low-power fans and miniature long-term rechargeable batteries. It can work continuously for more than 8 hours without external power supply after one charge, and can be used in various occasions. It is not only suitable for traffic police, road administration and related production workshop staff who are often in the environment of dust, haze and exhaust gas pollution, but also suitable for hospital medical staff and health and epidemic prevention personnel to wear and use. In particular, it is lightweight, beautiful, and easy to wear, and is also suitable for ordinary people to use on occasions such as riding motorcycles and bicycles.

4. Possess battery voltage safety warning and filter replacement warning functions, prompting the user to replace or charge the filter when the power supply voltage is lower than the normal working voltage, and the filter is too dusty, resulting in excessive working resistance. It can ensure that the helmet mask of the utility model is in the normal working state of dust-removing and bacteria-filtering when the user wears the helmet mask of the utility model.

5. The utility model can filter out dust particles ≥0.5 μm and bacterial viruses. And it has been proved by measurement that under the slightly polluted external environment, the air purification effect of wearing the helmet mask of the present utility model between the nose and the mouth, the cheeks outside the nose, the outer corners of the eyes and various parts of the chin can reach the national standard (GB/ T16292) tenth level or international standard level 4 air purification level, the number of bacteria is zero. Even in the heavily polluted external environment, its purification effect can still reach the level of 10,000-level purification, achieving a very ideal effect of filtering and purifying the air.

Description of drawings

Fig. 1～Fig. 4 is the structural representation of a specific embodiment of positive pressure air supply semi-open air purification helmet mask of the present utility model, and wherein, Fig. 1 is main view (full section), and Fig. 2 is left view (full section ), Fig. 3 is a bottom view, and Fig. 4 is a partial perspective view.

Fig. 5 is the electrical schematic diagram of the pressure early warning circuit in the positive pressure air supply semi-open type purified air helmet mask of the present invention.

Fig. 6 is the electrical schematic diagram of the voltage detection and early warning circuit in the positive pressure air supply semi-open type purified air helmet mask of the present invention.

Fig. 7 is a schematic diagram of wearing the positive-pressure air-supply semi-open air-purifying helmet mask of the present invention on the dummy head model for effect testing.

Detailed ways

The utility model will be further described in detail below in conjunction with the embodiments and accompanying drawings, but the implementation of the utility model is not limited thereto.

Referring to Figures 1 to 4, the positive pressure air supply semi-open air purification helmet mask of the present utility model is mainly composed of a helmet 1, a mask 2, a power unit, an air filter device, a static pressure box 4, and an air pressure and voltage alarm device, wherein :

The helmet 1 is a double-layer structure composed of an outer helmet shell 11 and an inner helmet shell 12, with a closed interlayer space between the two. The helmet 1 is made of engineering plastics, its size is designed according to the shape and average size of the human head, and its rigidity meets the relevant national impact resistance standards. The interlayer space has a gap of 15-25mm, which is used to place the power unit, air filter unit, static pressure box 4 and air pressure and voltage alarm unit.

The face shield 2 is arranged on the front portion of the helmet 1, and the face shield 2 body extends downward to cover the face of the human body (including the area from the forehead down to the chin and the outer corners of the left and right eyes). There is a gap between them; the mask 2 is an anti-fogging transparent cover body made of highly transparent PVC, and its surface is a smooth arc-shaped curved surface of the face. The face mask 2 is used to block the external air from blowing directly to the user's mouth and nose, and is combined with the helmet 1 to form a curtain for the wearer from the forehead down to the chin and covers the outer corners of the eyes and the cheeks. Positive pressure purification airflow drainage channel. When working, the speed of the positive pressure purification airflow is preferably 0.28m/s～0.3m/s, and the working distance is> 15cm (that is, the distance from the forehead to the mouth of ordinary people); so that the positive pressure purification airflow can make the wearer While breathing fresh and purified air, air viruses and bacteria that can block the external environment cannot enter its respiratory pathway. In addition, the purified airflow with a wind speed of about 0.3m/s will not cause discomfort to the wearer's skin, etc., making the wearer feel like a spring breeze, very comfortable, especially in summer, the purified airflow can also have a cooling effect. On the whole, it can make the wearer's breathing safe, comfortable and clean.

The power unit includes a fan 5 and a power supply, wherein the fan 5 is a miniature low-power fan 5, such as a MAGIC4012VB-C28 hybrid fan, whose air volume ranges from 13CFM to 20CFM, and the power consumption current is not more than 280mA. The power supply adopts a rechargeable long-life micro-battery pack 101, such as a lithium-ion battery pack with a capacity of ≥2700mAh, which can provide a DC voltage of ≥10V to ensure that the fan 5 can work continuously for more than 8 hours.

The air filter device is a filter 7 using an electret air filter material as a filter element 8, wherein the electret air filter material is an electret electrostatic synthetic fiber filter material. It uses electrostatic interaction to simultaneously filter out bacteria, viruses, exhaust gas and dust, and the filtration efficiency for particles with a particle size of 0.5 μm or more, bacteria and viruses is above 99.99%. The working life of the filter element 8 of the electret air filter material filter works in a slightly polluted environment, and can be as long as more than 7 years. Even if it works in a heavily polluted environment, the service life will be longer than half a year.

The plenum box 4 is arranged in the interlayer space, and its two ends are respectively an air inlet end and an air outlet end, wherein the air outlet end is located at the front of the helmet 1, and the air inlet end is located at the rear of the helmet 1; specifically, the The static plenum 4 is a circular arc-shaped channel with a smooth inner surface, and the arc-shaped channel extends from the rear of the helmet 1 across the top of the helmet 1 to the front of the helmet 1 . The arc-shaped channel is formed in the following manner: two wall panels 41 are provided in the interlayer space across the top of the helmet 1 from the rear of the helmet 1 and extend to the front of the helmet 1, and the two wall panels 41 The inner surface and the inner surfaces of the outer helmet shell 11 and the inner helmet shell 12 located between the two wall panels 41 jointly form a smooth and sealed arc-shaped air passage. Generally, the arc-shaped channel has a length of 80-125 mm and a cross-sectional area of 256-976 mm ² , and the pressurization effect is better. In this embodiment, the length of the arc-shaped channel is 100 mm, and the cross-sectional area is 400 mm ² . In addition, the arc-shaped channel can also be formed by a component independent of the outer helmet shell and the inner helmet shell, for example, the inner cavity of an arc-shaped pipe formed by injection molding, and the arc-shaped pipe is fixedly connected to the In the mezzanine space.

The blower fan 5 and the air filter device in the power unit are arranged on both sides of the plenum box 4 respectively, and adopt the arrangement mode of the blower fan 5 in front and the filter 7 in the rear, that is, the filter 7 is arranged at the rear of the helmet 1 On the air inlet end of the static pressure box 4, the blower fan 5 is arranged at the middle front part of the helmet 1. The filter 7 includes a filter seat, the filter element 8 is arranged in the filter seat, and the end of the filter seat is a detachable end cap, so that the filter element 8 can be replaced. In addition, an arrangement in which the fan 5 is placed in the rear and the filter 7 is placed in the front can also be used, which can also achieve the purpose of the utility model.

The front edge of the helmet 1 is provided with a blowing outlet 6 facing downwards, and the blowing outlet 6 communicates with the air outlet end of the static pressure box 4 . Specifically, the air outlet 6 is arranged between the outer helmet shell and the circular edge of the inner helmet shell at the front of the helmet 1, and the air outlet is an arc-shaped opening arranged along the front edge of the helmet 1, and the arc-shaped The length of the opening is slightly greater than the length from the outer edge of the wearer's left eye to the outer edge of the right eye.

Referring to the arrow in Figure 1, when working, under the pressurization of the fan 5 and the plenum box 4, the external air passes through the filter 7 and enters the plenum box 4 through the air inlet end of the plenum box 4, and passes through the plenum box 4. After the pressure box 4 is output from the air outlet of the static pressure box 4, it is finally blown out from the air outlet 6 to form a curtain-like wind belt.

Referring to Figure 5 and Figure 6, the air pressure and voltage alarm device includes a pressure sensing system and a voltage sensing system, wherein:

Referring to Fig. 5, the pressure sensing system includes a pressure sensor 9 for detecting the air pressure in the static pressure tank 4 and a pressure early warning circuit that sends an alarm when the required working resistance of the filter is too large, and the pressure sensor 9 has an accuracy higher than 10pa The electronic pressure sensor is used to sense the working pressure in the plenum box 4. When the filter 7 accumulates too much dust and the working resistance is greater than 240Pa, the switch will be activated. The pressure warning circuit includes a reference power supply, an inverter, a multivibrator and a buzzer 102 . When the filter 7 is working normally, its working resistance is less than 240Pa, so the electronic pressure sensor connected in parallel with the reference power supply is in an open circuit state, the input to the inverter is high level, and the output is low level after passing through the inverter , the multivibrator cannot work, cannot generate an oscillation signal, and the buzzer 102 does not emit an alarm sound; but when the filter 7 accumulates too much dust, resulting in a working resistance greater than 240Pa, the electronic pressure sensor is in a power-on state, giving the reverse phase The input of the multivibrator is low level, and the output is high level after passing through the inverter, thereby starting the multivibrator to generate an output rectangular wave signal, triggering the buzzer 102 to sound an alarm to remind the user to replace the filter 7 .

Referring to Figure 6, the voltage sensor system includes a voltage detection and early warning circuit for detecting the voltage of the power supply and giving an alarm when the voltage is too low, the voltage detection and early warning circuit includes a sampling circuit, an inverter, a multivibrator and a buzzer device 102. The sampling circuit is connected in parallel to the output terminal of the battery pack 101 to collect the voltage of the battery pack 101; when the voltage of the battery pack 101 is ≥10V, the collected voltage signal of the battery pack 101 is high level, and the output is low level after passing through the inverter , the multivibrator can’t work, can’t generate oscillating signal, and buzzer 102 doesn’t send alarm sound; It is low level, and the output is high level after passing through the inverter, thereby starting the multivibrator to work to generate an output rectangular wave signal, triggering the buzzer 102 to sound an alarm, to remind the user to replace the battery pack 101 or replace the battery pack 101 Group 101 is charged.

Referring to Fig. 1, the above-mentioned pressure sensor 9, buzzer 102, battery pack 101 and related circuit board 10 and wires are all arranged in the interlayer space; the user does not need to drag any tubes and lines to connect other wind sources when wearing it. For the power supply, there is only one power charging socket for charging the power supply, so it is light and beautiful, and easy to wear.

The effect of the positive pressure air supply semi-open helmet mask of the present utility model is further verified in conjunction with specific experiments below.

Referring to Fig. 7, the positive pressure air supply semi-open helmet mask of the present utility model is worn on the simulation head model, and it is placed in a glass box with a broad-spectrum aerosol generator specially imitating atmospheric pollution, respectively pressing International standards set lightly polluted environment (the concentration of suspended particles in the air is about 3×10 ⁵ /L); moderately polluted environment (the concentration of suspended particles in the air is about 10 ⁷ /L); and heavily polluted environment (The concentration of suspended particles in the air is about 10 ⁹ /L). Then under the working situation of starting the utility model's positive pressure air supply semi-open air purification helmet mask, the air velocity and bacteria and dust particles and air flow rate at each point of the nose, mouth, chin and both sides of the outer corners of the eyes and the cheeks wearing the head model The amount of sol was measured. The obtained effect is: the wind speed at each point is between 0.28 and 0.3m/s. In a lightly polluted environment, the amount of dust particles and aerosols with a particle size of 0.5 μm to 5 μm at each point is less than 350/m ³ , the amount of dust particles and aerosols with a particle size greater than 5 μm is zero, and the number of planktonic bacteria per m ³ in the air The number and the number of settled bacteria per collection dish within 30 minutes are also zero, which is better than the tenth level of the national standard cleanliness. In a moderately polluted environment, the amount of dust particles and aerosols from 0.5 μm to 5 μm at each point is less than 3385/m ³ , the amount of dust particles and aerosols larger than 5 μm is zero, and the number of airborne bacteria/m ³ and sedimentation bacteria Each dish/dish 30min is also zero, which is better than the national standard cleanliness level of 100. Even in a heavily polluted environment, the air cleanliness of each point is far better than the national standard cleanliness level of 10,000. To ensure that the wearer can breathe very clean and safe air in various polluted environments.

The above is a preferred implementation of the utility model, but the implementation of the utility model is not limited by the above content, and any other changes, modifications, substitutions, combinations, Simplification should be equivalent replacement methods, all of which are included in the protection scope of the present utility model.

Claims (10)

1. forced draft semi open model faceplate that purifies air, comprise the helmet, face shield, power set, air filter and air pressure and voltage alarm device, wherein, described face shield is arranged on the front portion of the helmet, face shield body extension downwards covers in outside the human face, has the gap between face shield and the human face; Described power set comprise blower fan and power supply; It is characterized in that:

Also comprise plenum chamber, this plenum chamber and described power set, air filter and air pressure and voltage alarm device all are arranged in the helmet, and wherein, the two ends of described plenum chamber are respectively air intake and outlet air end, and wherein outlet air end is positioned at the front portion of the helmet; The leading edge place of the described helmet is provided with blowing mouth down, and this blowing mouth is communicated with the outlet air end of plenum chamber;

Blower fan in the described power set and air filter are arranged at middle part and the air intake of plenum chamber respectively, and wherein, described air filter is for using electret air filtering material as the filter of filter core.

2. the forced draft semi open model according to claim 1 faceplate that purifies air, it is characterized in that, the described helmet double-decker that outer helmet shell and interior helmet shell combine of serving as reasons, form mezzanine space between outer helmet shell and the interior helmet shell, its gap is 15～25mm, and described plenum chamber, power set, air filter and air pressure and voltage alarm device all are arranged in this mezzanine space.

3. the forced draft semi open model according to claim 2 faceplate that purifies air is characterized in that described plenum chamber is the smooth circular arc passage of inner surface, and the top that this circular arc passage strides across the helmet by the rear portion of the helmet extends to the front portion of the helmet.

4. the forced draft semi open model according to claim 1 faceplate that purifies air is characterized in that, described blowing mouth is the circular arc opening that the leading edge along the helmet arranges.

5. the forced draft semi open model according to claim 4 faceplate that purifies air is characterized in that, the length of described circular arc opening is slightly larger than wearer's left eye outer rim to the length of right eye outer rim.

6. the forced draft semi open model according to claim 5 faceplate that purifies air, it is characterized in that, the cover body with shape of face slick and sly arc-shaped curved surface of described face shield for being made by the high transparent PVC of preventing atomization, this face shield and the described helmet combine formation to the wearer from forehead down to its chin and the covering curtain shape positive pressure purification air-flow drainage channel to two ectocanthion and cheek.

7. the forced draft semi open model according to claim 5 faceplate that purifies air is characterized in that the length of described plenum chamber is 80～125mm, and its cross section sectional area is 256～976mm ²

8. according to each described forced draft semi open model of claim 1～7 faceplate that purifies air, it is characterized in that described electret air filtering material is electret static synthetic fibers filtering materials.

9. the forced draft semi open model according to claim 1 faceplate that purifies air, it is characterized in that, described air pressure and voltage alarm device comprise pressure capsule system and voltage sensor system, wherein, pressure capsule system comprises for detection of the pressure sensor of plenum chamber internal gas pressure and the pressure early warning circuit that gives the alarm when the required working resistance of filter is excessive; Described voltage sensor system comprises voltage detecting and the early warning circuit that gives the alarm for detection of power source voltage and when the brownout; Described pressure early warning circuit comprises reference power supply, phase inverter, multivibrator and the buzzer that connects successively; Described voltage detecting comprises sample circuit, phase inverter, multivibrator and the buzzer that is connected successively with early warning circuit.

10. the forced draft semi open model according to claim 1 faceplate that purifies air, it is characterized in that, described power supply is that output voltage is the chargeable miniature lithium battery group of 10V, capacity 〉=2700mAh, described blower fan be the air quantity excursion between 13CFM～20CFM and static current of lcd be not more than the low-power consumption blower fan of 280mA.

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