KR101020171B1 - Apparatus and method for monitoring air filter - Google Patents

Abstract

The present invention relates to an air filter monitoring device and method for monitoring the contamination level of the air filter to inform the replacement time.

Air filter monitoring device according to an embodiment of the present invention, the air filter unit for filtering the contaminants through the air in the target space; A reference temperature detector configured to measure a temperature of the target space and detect a reference temperature; A temperature change detector including a flow path associated with the pollutant filtering and detecting a temperature change according to a change in air flow rate flowing through the flow path; And a pollution degree determination unit that determines the pollution degree of the air filter based on the reference temperature and the temperature change.

According to the present invention, a device equipped with a plurality of air filters can notify the user of the degree of contamination or replacement time for each air filter, and operation of a product equipped with an air filter monitoring device when detecting an air filter having a serious pollution level. It can also stop the operation of the contaminated air filter.

Air filter, contamination level, filter replacement time

Description

Air filter monitoring device and method {APPARATUS AND METHOD FOR MONITORING AIR FILTER}

1 is a schematic configuration diagram of an air filter monitoring device according to the present invention.

2 is a view showing the position of the temperature change detection unit according to an embodiment of the present invention.

3 is a cross-sectional view of a temperature change detector and a reference temperature detector according to an embodiment of the present invention.

4 is a circuit diagram illustrating a temperature change detector and a reference temperature detector.

5A to 5B are diagrams illustrating an internal configuration of a memory for storing pollution degree data.

6 is a view showing a temperature change detection unit having an air guide according to an embodiment of the present invention.

FIG. 7 is a diagram illustrating another embodiment of a position between a mesh and a temperature change detector of the air filter.

8 is a diagram illustrating an example of a temperature change detector having a mesh.

9 is a diagram illustrating an example of a temperature change detector having a protection mesh.                 

10 is a diagram illustrating an example of an air filter monitoring device including a plurality of air filters.

FIG. 11 is a diagram illustrating a circuit diagram of a temperature change detector and a reference temperature detector in the air filter monitor according to FIG. 10.

12 is a flowchart illustrating a process of detecting a pollution level of an air filter and performing a control operation according to the embodiment of the present invention.

13 is a flowchart illustrating a control operation for notifying the replacement time of the air filter according to the embodiment of the present invention.

14 is a cross-sectional view of the first and second temperature change detectors and the reference temperature detector according to another embodiment of the present invention.

FIG. 15 is a circuit diagram of the first and second temperature change detectors and the reference temperature detector.

FIG. 16 is a graph illustrating a change in voltage measured by the first and second temperature change detectors and the reference temperature detector according to an exemplary embodiment of the present invention.

17 is a graph illustrating a change in voltage measured by the first and second temperature change detectors and the reference temperature detector according to another embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

10: air filter unit 10-1, 10-2, 10-3: air filter

11: air filter frame 12: mesh of air filter

20: reference temperature sensing unit 21: reference temperature sensing element                 

22: closure of the reference temperature sensing unit

30: (first) temperature change detection unit 31: (first) temperature change detection element

33: air guide of the temperature change detection unit

34: mesh of temperature change detector 35: protective mesh of temperature change detector

40: pollution degree determination unit 50: pollution degree display unit

60: memory 70: speaker

80: detection board

90: second temperature change detection unit 91: second temperature change detection element

The present invention relates to an apparatus and method for monitoring an air filter, and more particularly, to an apparatus and method for measuring the contamination level of the air filter and informing the user of the replacement time of the air filter.

With the industrialization, environmental pollution is rapidly progressing, and in particular, as the concern about air pollution increases, the use of air purifiers is increasing day by day. Generally, the air purifier is equipped with an air filter for removing the dust in the air. It is. Not only an air purifier but also an air conditioner used for cooling in summer, an air filter for removing dust in the indoor air is used. The demand for home appliances using such an air filter is increasing.                         

In general, an air filter removes contaminants in the air by filtering using a mesh without permeating contaminants such as dust, pollen, asbestos, industrial dust, and the like contained in the air flowing into the filter. However, dust (contaminants) that do not penetrate the air filter continues to accumulate in the filter, thereby reducing the permeation area of air passing through the air filter. As the transmittance decreases as described above, a phenomenon occurs in which air flows to another gap portion without passing through a predetermined mesh portion, and this phenomenon causes a problem of decreasing dust removal efficiency in an apparatus equipped with an air filter.

In addition, if the contaminated air filter is used continuously for a long time without replacing the air filter, bacteria may be rather harmful to the human body due to the growth of bacteria due to the dust of the air filter.

For the various reasons mentioned above, the air filter is preferably replaced after it is used for a certain period of time.

The usual method of determining the replacement time of the air filter is to calculate the service period and to determine the replacement time uniformly. However, the method of calculating the usage period is calculated under the assumption that the air filter is used for a predetermined time in a space where the degree of contamination is constant, and includes the following problems.

First, since the amount of dust varies depending on the location where the device using the air filter is installed, the replacement time of the air filter should also be changed in consideration of the installation location. In other words, because the size or distribution of dust varies depending on the installation site, the amount of dust filtered through the air filter may also be reflected.

Secondly, the amount of air treated in the apparatus using the air filter depends on the discharge air volume of the air filter, and thus the degree of contamination of the air filter should further consider the throughput of air associated with the discharge air volume as well as the period of use.

On the other hand, in a device that does not apply even the conventional method of notifying the replacement time of the air filter by simply calculating the use time of the air filter, the user has to check the state of the air filter directly in order to know when to replace the air filter. There is this. In particular, when using a plurality of air filters with different dust collection performance in a single air cleaning device, the replacement timing of each air filter is not the same, and the user needs to remember or check the replacement time by each air filter. There is a feeling.

The present invention has been made to improve the prior art as described above, it is an object of the present invention to provide an apparatus and method for monitoring the air filter to automatically measure the contamination of the air filter to inform the user.

It is an object of the present invention to provide a method and apparatus which can determine the replacement timing of an air filter more specifically in consideration of the degree of contamination of the actual air filter rather than the period of use.

It is another object of the present invention to provide an apparatus and method for individually measuring the pollution level of each air filter in a device having a plurality of air filters and displaying the resulting message.

It is still another object of the present invention to provide an apparatus and method for preventing the operation of an air filter seriously contaminated enough to contaminate indoor air after a replacement time.

It is still another object of the present invention to provide an air filter monitoring apparatus and methods having various structures to more accurately measure the degree of contamination.

In order to achieve the above object and to solve the problems of the prior art, the present invention comprises: an air filter unit for filtering contaminants through the air in the target space; A reference temperature detector configured to measure a temperature of the target space and detect a reference temperature; A temperature change detector including a flow path associated with the pollutant filtering and detecting a temperature change according to a change in air flow rate flowing through the flow path; And a pollution degree determining unit configured to determine the pollution degree of the air filter based on the reference temperature and the temperature change.

According to one aspect of the invention, the step of measuring the reference voltage for comparing the degree of air pollution and storing in the memory; Measuring a room temperature at which the air filter is installed; Measuring a voltage value according to an air pollution level of the air filter; And calculating the contamination level of the air filter by comparing the measured voltage value with a reference voltage value corresponding to the pollution level of the stored air filter according to the measured room temperature. Monitoring method is provided.                     

Hereinafter, with reference to the accompanying drawings will be described embodiments of the present invention;

1 shows a schematic configuration diagram of an air filter monitoring apparatus according to the present invention. As shown in FIG. 1, the air filter monitoring device includes an air filter unit 10, a reference temperature detector 20, a temperature change detector 30, a pollution degree determination unit 40, a pollution degree display unit 50, and a memory ( 60, and a speaker 70. The function of each component will be described in detail with reference to FIG. 1.

The air filter unit 10 performs a function of filtering (filtering) contaminants through the air in the target space where the air filter monitoring apparatus is installed. The air filter unit 10 may include one or a plurality of air filters depending on the use place and purpose.

The reference temperature detector 20 measures the temperature of the target space and detects the reference temperature. As one example, the reference temperature sensor 20 is installed in a separate space (for example, a closed space) that is not affected by the air flow through the air filter, so that the reference temperature sensor 20 Detect room temperature

The temperature change detector 30 is installed in a space separated from the reference temperature detector 20 and includes a flow path through which air can flow. The flow rate of the air flowing through the flow path is changed in association with the contaminant filtering of the air filter, and the temperature change detector 30 detects the temperature change according to the change of the air flow rate.

The pollution degree determination unit 40 determines the pollution degree of the air filter based on the reference temperature detected by the reference temperature detection unit 20 and the temperature change detected by the temperature change detection unit 30. That is, the voltage value according to the reference temperature and the temperature change is measured, and the contamination value of the air filter is determined (measured) by comparing the measured value with the reference value (pollution degree data) previously stored in the memory 60. A more detailed description of the pollution degree will be described later.

In addition, the pollution degree determination unit 40 may determine the replacement time of the air filter according to the measured pollution degree. As an example for determining the replacement time, when the predetermined pollution degree value is exceeded, it can be determined that the replacement time has arrived. As a further embodiment, the pollution degree determining unit 40 according to the present invention may stop the operation of the air filter when the air filter that has passed the replacement time is not replaced and continues to operate. That is, it is also possible to stop the operation of the device equipped with the air filter after the replacement time or the device for monitoring the state of the air filter. In addition, when the air filter is seriously detected, the product equipped with the air filter monitoring device may be stopped so that the product no longer operates with the contaminated filter.

The pollution degree display unit 50 displays a message indicating a pollution degree or replacement time of the air filter on the display according to the determination result of the pollution degree determination unit 40. For example, you can display a message such as "Current air filter has 95% contamination. Please replace the air filter." As an example of the display method, the pollution degree display unit 50 may display the message associated with the pollution degree of the air filter step by step or temporarily display according to the pollution level. In addition, the pollution degree determination unit 40 may transmit a text message or voice message indicating the pollution degree of the air filter or a replacement time thereof to the mobile communication terminal of the air filter manager when the device using the air filter can communicate.                     

The memory 60 stores the pollution degree data as a reference value regarding the pollution degree. The stored pollution degree data is used by the pollution determination unit 50 to measure pollution. A more detailed description of the pollution degree data will be described later.

In addition, the air filter monitoring apparatus according to the present invention may further include a speaker 70, the speaker 70 may transmit a pollution degree warning message or a warning sound according to the determination result of the pollution degree determination unit 40. As an example, the speaker 70 may be included as some component of the pollution degree indicator 50.

2 is a view showing the position of the temperature change detection unit 30 according to an embodiment of the present invention. The air filter 10 may include an air filter frame 11 and a mesh 12, and the temperature change detector 20 may be installed over the air filter frame 11. As shown in FIG. 2, the dust in the air passing through the mesh of the air filter is filtered and accumulated to fill the empty space of the mesh, thereby reducing the air flow rate through the mesh. As a result, the air flow is disturbed by the pressure difference between the front end and the rear end of the filter, and the air flow finds a flow path in addition to the mesh portion. Therefore, more air flows into the flow path of the artificially drilled temperature change detector 30. Will flow.

In the present invention, the blocking rate is measured as an example of the degree of contamination. The blockage rate indicates the degree of decrease in the flow rate of air passing through the air filter due to contaminants caught on the mesh of the air filter. For example, when the blockage rate is 75%, the air blockage rate is 0%. This means that 75% of the air flow that could pass through the filter does not pass through the air filter.                     

3 is a cross-sectional view of the reference temperature sensor 20 and the temperature change detector 30 according to an embodiment of the present invention.

As shown in FIG. 3, the air passing through the mesh 12 flows into the flow path of the temperature change detection unit 30, which is a new passage, as dust accumulates in the mesh. The pollution detection board 80 includes a reference temperature sensing element 21 and a temperature change sensing element 31.

As a preferred embodiment of the present invention, the reference temperature sensor 20 and the temperature change detector 30 are arranged in separate spaces so that the detection zones are separated from each other. The closing part 22 of the reference temperature sensing unit 20 measures the temperature of the outside of the apparatus, that is, the room in which the apparatus is installed, rather than the internal temperature of the apparatus in which the reference temperature sensing element 21 is equipped with the air filter. In order to separate the space inside the apparatus from the reference temperature sensing element 21. That is, the reference temperature sensor 20 is installed in a closed space that is not affected by the air flow through the mesh 12 of the air filter, thereby accurately measuring the room temperature of the space in which the device equipped with the air filter is installed. .

4 is a circuit diagram of the reference temperature sensor 20 and the temperature change detector 30 according to an embodiment of the present invention.

The reference temperature detector 20 and the temperature change detector 30 each include a thermistor. A thermistor is a semiconductor element for temperature detection, and has a characteristic in which a resistance value changes as temperature increases. As an example of a thermistor, a thermistor having the characteristics of negative temperature coefficient (NTC) whose resistance decreases as the temperature increases, and a positive resistance temperature coefficient (PTC) that increases the resistance when the temperature increases There is a thermistor with the characteristic of Temperature Coefficient. In the detailed description of the present invention, embodiments using thermistors having a negative resistance temperature coefficient (NTC) will be described above. However, the technical concept applied to the embodiments may be applied to the thermistors having a constant resistance temperature coefficient (PTC). .

As shown in FIG. 4, the NTC1 and the resistor R1 connected in series thereto correspond to the temperature change sensing element 31, and the NTC2 and the resistor R2 connected in series thereto correspond to the reference temperature sensing element 21, respectively. Voltage distribution is made between the resistors. The temperature change sensing element 31 and the reference temperature sensing element 21 may be connected in parallel as shown in FIG. 4.

Due to the dust accumulated in the mesh, air of a higher flow rate flows in the flow path of the temperature change detection unit 30, and an increase in the air flow rate affects the temperature of the temperature change detection element 31, causing a temperature drop. . The temperature drop of the temperature change sensing element 31 (NTC1) causes an increase in the NTC1 resistance value, thus reducing the magnitude of the voltage Vout1 for R1 in the voltage distribution relationship with NTC1.

In addition, since the temperature change of the temperature change detecting element 31 is affected by not only the flow rate of air flowing therein but also the temperature of the indoor air, the reference temperature detecting unit 20 serves as the reference temperature sensing element 21 in the room temperature. Needs to be measured. For example, if the reference temperature in the room rises, the resistance value of the reference temperature sensing element 21 (NTC2) is reduced, thus increasing the magnitude of the voltage Vout2 relative to R2 in the voltage distribution relationship with NTC2. do.

As a result, the change in temperature and the change in reference temperature due to the flow rate increase can be measured by the voltages Vout1 and Vout2 measured at the respective resistances.

By using the above-described circuit characteristics of FIG. 4, the present invention senses a change in resistance value of the NTC element and a change in flow rate associated therewith by using a change in voltage value measured in the resistance, thereby ultimately contaminating the air filter. We would like to propose a new method to measure the inverse of.

To this end, in the present invention, the pollution degree data is constructed as a reference value in relation to the reference temperature and the resistance value, and the pollution degree is measured by referring to the pollution degree data using the voltage value measured by the actual air filter monitoring device. Hereinafter, with reference to FIGS. 5A and 5B, how the pollution degree determination unit 40 determines the pollution level will be described in detail.

5A and 5B show an internal configuration of a memory for storing pollution degree data according to the present invention. As shown in FIGS. 5A and 5B, the pollution degree data stores and stores the voltages Vout1 and Vout2 applied to the resistors connected to the NTC elements NTC1 and NTC2 in relation to the reference temperature and the resistance according to the blockage rate. . Accordingly, when the voltages applied to the NTC element are measured according to the reference temperature and the resistance, the pollution degree determining unit 40 may measure the blockage rate (contamination degree) by referring to the pollution degree data of FIGS. 5A and 5B.

5A and 5B, when the voltage Vin applied to the entire circuit of FIG. 4 is 5 (V) or 10 (V), the reference temperature is changed to 20 (° C) or 26 (° C) or the resistance While the value is changed to 50 (막) or 100 (Ω), the voltage value according to the blockage rate (%) is measured and stored. As a more preferred embodiment according to the present invention, the overall applied voltage Vin, the reference temperature, the resistance value is more varied, or the unit of the blockage rate more finely (for example, the blockage rate in Figures 5a and 5b) Is stored in 25% units, but more precisely, the contamination data can be measured and stored in 10% or less units.) By repeatedly measuring the voltage value and obtaining the average value, the reliability of the pollution data can be further improved.

5A and 5B, it can be seen that the voltage Vout1 applied to R1 decreases as the blocking rate increases, and the voltage Vout2 applied to R2 has a substantially constant value.

5A and 5B, as a specific example of the blockage rate measurement, when the total applied voltage Vin is 5 (V), the reference temperature is 26 (° C), and the resistance is 100 (kPa), Vout1 If 2.76 (V) and Vout2 were measured as 2.76 (V), the blockage rate could be calculated as 25 (%).

On the other hand, in consideration of the blocking rate measured in this way, the pollution degree determining unit 40 can determine the replacement time of the air filter. As an example, if the blocking rate is set to 75% as a reference value for the timing of replacement, the replacement may be determined when the blocking rate exceeding the reference value is measured.

According to the present invention, various embodiments related to the temperature change detection unit are further provided. Hereinafter, with reference to FIGS. 6 to 11, it will be described in detail.

6 illustrates a temperature change detector 30 including an air guide 32. The temperature of the NTC element provided in the temperature change sensing element 31 depends on the heat taken away by the amount of air contacted. For example, the shape of the flow path may be modified in various forms other than the straight line as shown in FIG. The temperature change detector 30 of FIG. 6 includes an air guide 32, and the air guide 32 may change the cross-sectional area of the flow path to adjust the flow rate of air passing through the temperature change detector 30. Structure. According to FIG. 6, the flow path may be configured to have a smaller width as it approaches the temperature change sensing element 31, thereby narrowing the cross-sectional area of the flow path. As shown in Figure 6, by configuring the cross-sectional area of the flow path in various ways, it is possible to change the flow rate in contact with the temperature change sensing element, and eventually various voltage measurement is possible according to the characteristic value of the temperature change sensing element.

Figure 7 shows another embodiment of the position between the mesh 12 and the temperature change detection unit 30 of the air filter in accordance with the present invention.

In the embodiment according to FIG. 7, the temperature change detecting element 31 is installed at the rear end of the air filter mesh 12 so that air passing through the air filter 12 passes through the flow path of the temperature change detecting unit 30. It is. In FIG. 3, the temperature change detector 30 is a space for performing air flow by performing a detour function due to an increase in pollutants of the mesh, while the temperature change detector 30 in FIG. Due to the phenomenon that the air flow is lowered provides a method for measuring the contamination of the air filter.                     

8 illustrates an example of the temperature change detector 30 having a mesh. As shown in FIG. 8, the temperature change detection unit 30 further includes a mesh 33 for filtering contaminants of air introduced into the front end of the temperature change detection element 31. As an example, the mesh 33 of the temperature change detector 30 is denser than the mesh 12 of the air filter, and thus may detect the temperature change more sensitively than the mesh of the air filter mesh 12.

9 illustrates another example of the temperature change detector 30 including a mesh, and includes a protective mesh 34 at a front end of the temperature change detector 30. The protective mesh 34 blocks the contaminants large enough to affect the operation of the temperature change detecting element 31 to flow into the flow path in order to prevent the temperature change detecting element 31 from being degraded due to air pollution. .

Meanwhile, the pollution degree data according to FIGS. 5A and 5B may have different measured values depending on the structure of the temperature change detector illustrated in FIGS. 6 to 9, and thus, reference values corresponding to the structure may be individually measured to obtain pollution degree data. The storage can further increase the reliability of the contamination measurement.

FIG. 10 shows another example of the air filter monitoring apparatus in which the air filter unit 10 includes a plurality of air filters 10-1, 10-2, and 10-3. The air filter unit 10 may include a plurality of air filters according to the use place and purpose, and the plurality of air filters may not have the same dust collection performance or may have the same operating environment. You may not. Therefore, it is more preferable to determine the pollution degree of the plurality of air filters and the replacement time thereof uniformly, instead of individually determining them through specific measured values.

According to FIG. 10, the temperature change detector 30 detects a temperature change associated with each air filter, and the pollution degree determiner 40 determines the pollution degree based on each temperature change.

FIG. 11 illustrates a detailed circuit diagram of the reference temperature sensor 20 and the temperature change detector 30 in the air filter monitoring device of FIG. 10.

As shown in FIG. 11, in addition to the NTC element NTC1 for measuring the temperature change of the air filter 10-1, the NTC elements NTC3 for measuring the temperature change for the air filters 10-2 and 10-3. And NTC4) and its associated resistors R3 and R4. In a preferred embodiment, the reference temperature sensing element NTC2 is installed in a space separate from the temperature change sensing elements NTC1, NTC3, and NTC4, respectively. According to FIG. 11, the resistances R1, R2, R3, and R4 are changed according to the resistance value change of the reference temperature sensing element NTC2 and the temperature change sensing elements NTC1, NTC3, and NTC4 according to the degree of contamination of each air filter. By measuring the voltages Vout1, Vout2, Vout3, and Vout4 respectively, the contamination levels of the air filters 10-1, 10-2, and 10-3 can be measured separately. Since the method of measuring the pollution level in each air filter using the pollution degree data has been described above, it will be omitted here.

According to FIG. 11, in an air filter monitoring apparatus including a plurality of air filters, only one portion (for example, a reference temperature sensing unit) commonly used in the temperature change detection unit 30 may be used for all the plurality of air filters. By configuring the circuit, it is possible to install the circuit more simply, so that the degree of contamination and its replacement time can be easily measured for a plurality of air filters at once.

12 is a diagram illustrating a process of detecting a pollution degree of an air filter and performing a control operation according to the air filter device according to the present invention. Referring to Figure 12 will be described in detail the processes performed in each step.

First, in step 1210, a reference voltage value for comparing the degree of air pollution is measured, and in step 1220, the pollution degree determining unit 40 stores the measured reference voltage value in the memory 60 as pollution degree data. As an example for measuring the reference voltage value, the temperature change detector may include a thermistor element for measuring the reference temperature and the temperature change, and measure voltage values applied to a resistor connected to the thermistor element. These reference voltage values are measured in association with the reference temperature and resistance values according to the blockage rate and the measurements are stored as contamination data.

Next, in step 1230, the reference temperature sensing unit 20 measures the indoor (reference) temperature at which the device with the air filter is installed through the reference temperature sensing element 21. In operation 1240, the temperature change detector 30 measures the voltage value applied to the resistance R1 connected to the temperature change detection element 31 to measure the voltage value according to the degree of air pollution of the air filter.

In operation 1250, the pollution degree determination unit 40 may determine the reference voltage value stored in the memory 60 according to the room temperature measured by the reference temperature sensor 20 and the degree of air pollution measured by the temperature change detection unit 30. Compare the voltage values accordingly. In step 1260, the pollution level (degree of contamination) of the air filter is calculated according to the comparison result of step 1260.

In operation 1270, the pollution degree display unit 50 displays a message indicating the pollution level of each air filter included in the air filter unit 10 according to the result calculated by the pollution degree determination unit 40. In addition, the speaker 70 transmits a message indicating the degree of contamination of each air filter provided in the air filter unit 10 according to the result calculated by the pollution degree determining unit 40.

13 is a flowchart illustrating a control operation for notifying the replacement time of the air filter according to the embodiment of the present invention.

Referring to FIG. 13, in operation 1310, the pollution degree determining unit 40 displays a message indicating the time to replace the air filter on the pollution degree display unit 50 according to a result of determining the pollution level of the air filter. In addition, the pollution degree determination unit 40 may send a message to the speaker 70 informing the replacement time of the air filter according to the pollution degree determination result.

In step 1320, it is determined whether a predetermined replacement time has elapsed. If it is determined that the designated replacement time has elapsed, it is determined in step 1330 whether the air filter is replaced. If it is determined that the replacement air filter has not been replaced, the operation of the air filter after the replacement time is stopped in step 1340.

On the contrary, if it is determined that the air filter indicating the replacement time has been replaced, the operation of monitoring the contamination level of the air filter as shown in FIG. 12 is continuously performed in step 1350.                     

According to FIG. 13, the operation of the air filter that has not been replaced but the replacement time has elapsed automatically prevents the problem that the indoor air is further contaminated due to contamination of the air filter.

14 and 15 illustrate a modification of the temperature change detection unit according to another embodiment of the present invention, and relate to an embodiment in which a pollution degree may be determined using two temperature change detection units. 14 is a cross-sectional view of the first and second temperature change detectors 30 and 90 and the reference temperature detector 20, and FIG. 15 is a reference temperature detector 20 and a first detector according to another embodiment of the present invention. A circuit diagram of the temperature change detector 30 and the second temperature change detector 90 is illustrated.

Referring to FIGS. 14 and 15, the reference temperature detector 20, the first temperature change detector 30, and the second temperature change detector 90 may include thermistors NTC1, NTC2, NTC5 and thermistors. Resistors R1, R2, and R5 in series with NTC1, NTC2, and NTC5, respectively. Voltage distribution is made between the thermistors NTC1, NTC2, NTC5 connected in series and resistors R1, R2, R5, respectively. The first temperature change sensing element 31 (NTC1), the second temperature change sensing element 91 (NTC5), and the reference temperature sensing element 21 (NTC2) are respectively connected in parallel as shown in FIG. 15. The reference temperature sensing unit 20 and the reference temperature sensing element 21, which is installed in a separate space 22 is not affected by the change in the flow rate of air passing through the mesh 12 of the air filter and the reference The resistor R2 is connected in series with the temperature sensing element 21 (NTC2). The first temperature change detector 30 may include a thermistor NTC1 as the first temperature change detector 31 and a first temperature change detector 31 in a flow path of air that does not pass through the mesh 12 of the air filter. It consists of a resistor (R1) in series with NTC1). The second temperature change detection unit 90 includes a thermistor NTC5 as the second temperature change detection element 91 and a second temperature change monitoring element 91 (NTC5) in a flow path of air passing through the mesh 12 of the air filter. It is composed of a resistor (R5) connected in series with). As shown in FIG. 14, the second temperature change detection unit 90 positions the second temperature change detection element 91 (NTC5) on the rear surface of the mesh 12 of the air filter to position the mesh 12 of the air filter. The temperature change according to the flow rate of the air passing through can be detected.

The first temperature change detector 30 measures the voltage Vout1 of the resistor R1 connected in series with the first temperature change detector 31 (NTC1), and measures the first temperature change detector 31 (NTC1). Detects the change in temperature according to the flow rate of the air that does not pass through the mesh 12 of the air filter through the). The first temperature change detector 30 detects that the temperature has dropped as more air flows into the flow path of the first temperature change detector 30 due to dust accumulated in the mesh 12 of the air filter. do. Since the internal resistance of the first temperature change detecting element 31 (NTC1) increases as the temperature decreases, the voltage with respect to the resistor R1 having a voltage distribution relationship with the first temperature change detecting element 31 (NTC1). (Vout1) is relatively reduced. That is, as the degree of contamination of the air filter increases, the temperature detected by the first temperature change detecting element 31 (NTC1) decreases, and the voltage applied to the first temperature change detecting element 31 (NTC1) increases, while the first temperature increases. The voltage Vout1 measured at the resistor R1 connected in series with the change sensing element 31 NTC1 becomes low.

The second temperature change detector 90 measures the voltage Vout5 of the resistor R5 connected in series with the second temperature change detector 91 (NTC5), and the second temperature change detector 91 (NTC5). Detects the temperature change according to the flow rate of the air passing through the mesh 12 of the air filter through the). As the pollution degree of the air filter increases, the second temperature change detector 90 installed at the rear of the air filter may change the second temperature change as a small amount of air flows through the flow path due to dust accumulated in the mesh 12 of the air filter. The temperature rise is sensed by the sensing element 91 (NTC5). When the temperature detected by the second temperature change sensing element 91 (NTC5) is high, the voltage applied to the second temperature change sensing element 91 (NTC5) is lowered, and the second temperature change sensing element 91 (NTC5) The voltage Vout5 measured at the resistor R5 connected in series with the signal becomes high.

As described above, as the amount of dust accumulated in the mesh 12 of the air filter increases, that is, as the pollution degree of the air filter increases, the voltage Vout1 measured by the first temperature change detector 30 gradually decreases. In addition, the voltage Vout5 measured by the second temperature change detector 90 gradually increases. At this time, the voltage Vout2 measured by the reference temperature sensor 20 is constant. The above contents can be summarized by Equation 1 together with the graph shown in FIG. 16.

Vout2 = K (constant), const (constant)

Vout5 → Vout2,

Equation 1 is measured by the reference temperature detector 20 by increasing the voltage Vout5 measured by the second temperature change detector 90 as shown in FIG. 16 as the pollution degree of the air filter increases. The voltage Vout2 is gradually approached.

In addition, if it is assumed that the contamination of the air filter has reached the limit and it is time to replace the air filter, it is represented by the following equation (2).

∴ Vout5 ≒ Vout2

Equation 2 is that when the pollution degree of the air filter is serious enough to replace the air filter, the voltage Vout5 measured by the second temperature change detector 90 continuously increases, and as a result, the reference temperature detector 20 This indicates that the voltage Vout2 is equal to the measured voltage.

In addition, as the mesh 12 of the air filter is blocked, the voltage Vout1 measured by the first temperature change detector 30 may be expressed as Equation 1 of Equation 3 below.

Vout1 → 0 ------------------------------------- (1)

∴ Vout2-Vout1 ≒ Vout5-Vout1

(Vout2-Vout1)-(Vout5 -Vout1) ≒ 0 ---------- (2)

(Vout2-Vout1) / (Vout5-Vout1) ≒ 1 ----------- (3)

(Vout5-Vout1) / Vout2 ≒ 1 --------------------- (4)

The pollution degree determination unit 40 is such that the difference between the voltage Vout5 measured by the second temperature change detection unit 90 and the voltage Vout5 measured by the reference temperature detection unit 20 converges to “0”. Determine the level of contamination. That is, the pollution determination unit 140 converges Equation (1) or (2) described in Equation (3) to "0", and Equations (3) and (4) described in Equation (3) are "1". In case of convergence, it is determined that the air filter has reached its limit and the air filter needs to be replaced.

In other words, the pollution degree determining unit 40 determines that the absolute value of the difference between the voltage Vout1 measured by the first temperature change detection unit 30 and the voltage Vout5 measured by the second temperature change detection unit 90 is determined. If the difference between the voltage Vout2 measured by the reference temperature detector 20 and the voltage Vout1 measured by the first temperature change detector 30 is equal to the absolute value, the contamination of the air filter reaches a limit. You can judge that.

As another example, it should be noted that the above mathematical approach is capable of the opposite interpretation and application by the circuit approach. For example, the opposite interpretation by the circuit approach is to use a thermistor with a constant temperature coefficient instead of a thermistor with a negative temperature coefficient or to connect the thermistor and a resistor in parallel instead of a series connection. It is possible in the case.

Vout2 = K (constant), const (constant)

Vout5 → Vout1,

Vout1 → Vout5,

In Equation 4, the voltage Vout2 measured by the reference temperature detector 20 is constant, and as the pollution degree of the air filter increases, the second temperature change detector 90 is measured as shown in the graph of FIG. 17. The voltage Vout5 gradually decreases, and the voltage Vout1 measured by the first temperature change detector 30 gradually increases. That is, the voltage Vout5 measured by the second temperature change detector 90 increases as the voltage Vout1 measured by the first temperature change detector 30 increases as the pollution degree of the mesh 12 of the air filter increases. By decreasing), the magnitudes of the measured voltages Vout1 and Vout5 are gradually approached.

Here, if it is assumed that the contamination of the air filter reaches the limit and the air filter needs to be replaced, it may be expressed as Equation 5 below.

∴ Vout5 ≒ Vout1 ----------------------------- (1)

∴ Vout2-Vout1 ≒ Vout5-Vout1 ------------- (2)

(Vout2-Vout1)-(Vout5-Vout1) ≒ 0 --------- (3)

(Vout2-Vout1) / (Vout5-Vout1) ≒ 1 ----------- (4)

(Vout5-Vout1) / Vout2 ≒ 0 --------------------- (5)

The pollution degree determining unit 40 substitutes the values of the measured voltages Vout1, Vout2, and Vout5 into Equation 5, and as a result of Equation (3) and Equation (5) converges to " 0 " Determine the contamination level of the air filter according to the degree to which 4) converges to "1", and determine when to replace the air filter. That is, the pollution degree determining unit 40 determines that the difference between the voltage Vout1 measured by the first temperature change detector 30 and the voltage Vout5 measured by the second temperature change detector 90 is '0'. The degree of convergence determines the degree of contamination of the air filter. Therefore, the pollution degree determining unit 40 determines that the absolute value of the difference between the voltage Vout1 measured by the first temperature change detector 30 and the voltage Vout5 measured by the second temperature change detector 90 is the reference temperature. If the absolute value of the difference between the voltage Vout2 measured by the detector 20 and the voltage Vout1 measured by the first temperature change detector 30 is equal to the absolute value, it is determined that the pollution degree of the air filter has reached the limit. Can be.

As such, the pollution degree determining unit 40 may calculate the voltages Vout1, Vout2, and Vout5 measured by the resistors R1, R2, and R5 connected in series with the three thermistors NTC1, NTC2, and NTC5, respectively. The approach enables automatic determination of air filter contamination and when to replace the air filter without being affected by the environment.

14 to 17, the voltage measured by the first temperature change detector 30 and the second temperature change detector 90 without storing the pollution degree data of the air filter according to each temperature in the memory. The pollution value of the air filter may be affected by an environmental variable by a difference value between Vout1 and Vout5 or a difference value between voltages Vout1 and Vout2 measured by the first temperature change detector 30 and the reference temperature detector 20. Can be measured in real time or step by step without receiving.

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above-described embodiments, which can be variously modified and modified by those skilled in the art to which the present invention pertains. Modifications are possible. Accordingly, the spirit of the present invention should be understood only by the claims set forth below, and all equivalent or equivalent modifications thereof will belong to the scope of the present invention.

According to the present invention, there is provided a method and apparatus for automatically informing the degree of contamination and the replacement time by measuring the degree of contamination of the air filter in a device using the air filter.

In addition, according to the present invention, there is provided a method and apparatus for determining the replacement time through a specific measurement of the degree of contamination, rather than the conventional uniform standard according to the period of use.

In addition, according to the present invention, it is possible to prevent the air pollution generated by the contaminated air filter by blocking the operation of the air filter after the replacement time in the device having the air filter.

In addition, according to the present invention, it is possible to improve the reliability of the contamination measurement by providing the air filter monitoring apparatus and methods having various structures.

Claims (15)

An air filter unit configured to filter contaminants by passing air in the target space; A reference temperature detector configured to measure a temperature of the target space and detect a reference temperature; A temperature change detector including a flow path associated with the pollutant filtering and detecting a temperature change according to a change in air flow rate flowing through the flow path; And And a pollution degree determining unit configured to determine the pollution level of the air filter based on the reference temperature and the temperature change. The reference temperature detector and the temperature change detector include first and second thermistors, respectively, The first and second thermistors are respectively connected in series with a first resistor and a second resistor having a predetermined resistance value. The pollution degree determining unit determines the pollution degree based on the magnitudes of the first voltage and the second voltage measured by the first and second resistors, respectively. The method of claim 1, Further comprising a pollution indicator, And the pollution display unit transmits a message related to the pollution degree to a speaker or displays the message on a display. delete delete The method of claim 1, A memory for storing pollution degree data in association with the reference temperature and the resistance value, And the pollution degree determining unit determines the pollution level by referring to the pollution degree data. The method of claim 1, The temperature change detection unit further comprises an air guide for adjusting the cross-sectional area of the flow path. The method of claim 1, And the temperature change detector is installed at a rear end of the air filter unit, and the air passing through the air filter unit passes through the flow path of the temperature change detector. The method of claim 1, And the air filter unit and the temperature change detector include first and second meshes, respectively, and the second mesh is denser than the first mesh. The method of claim 1, The temperature change detector includes a protection mesh, wherein the protection mesh prevents contaminants large enough to affect the operation of the temperature change detector to enter the flow path. The method according to any one of claims 1, 2 and 5 to 9, The air filter unit includes a plurality of air filters, The temperature change detector detects a temperature change associated with each of the air filters, respectively. And the pollution degree determining unit determines the pollution degree of each air filter individually based on each temperature change. The method of claim 1, The reference temperature sensing unit includes a thermistor and a first resistor connected to the thermistor, The temperature change detection unit A first temperature change sensing element including a thermistor configured to sense a temperature change according to a change in air flow rate flowing through the flow path; A second resistor connected to the first temperature change sensing element; A second temperature change sensing element installed at a rear surface of the air filter unit and including a thermistor configured to sense a temperature change according to a change in air flow rate passing through the air filter; And A third resistor connected to the second temperature change sensing element Air filter monitoring device comprising a. The method of claim 11, The first, second and third resistors are connected in series with respective thermistors, The pollution degree determining unit may be configured such that the difference between the first voltage measured by the first resistor and the third voltage measured by the third resistor converges to “0” or the second voltage measured by the second resistor is “0”. Air filter monitoring device characterized in that it determines the degree of contamination of the air filter by the degree of convergence. The method of claim 11, The thermistor has a characteristic of a constant resistance temperature coefficient, The pollution degree determining unit determines the contamination level of the air filter by the degree that the difference between the second voltage measured by the second resistor and the third voltage measured by the third resistor converges to “0”. Air filter monitoring device. A method for monitoring an air filter in the apparatus of claim 1, Measuring a reference voltage for comparing the degree of air pollution and storing the pollution degree data in a memory; Measuring a room temperature at which the air filter is installed; Measuring a voltage value according to an air pollution level of the air filter; And Calculating a degree of contamination of the air filter by comparing the measured voltage value with the stored pollution degree data according to the measured room temperature Monitoring method of an air filter comprising at least. The method of claim 14, Notifying when to replace the air filter, and determining whether to replace the air filter after a predetermined time elapses; And Stopping the operation of the air filter when it is determined that the air filter is not replaced Air filter monitoring method further comprising.

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