JP2018017680A - Air cleaning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air cleaning device capable of improving detection accuracy of fine particles in a dirt detection unit.SOLUTION: A controller 21 includes: air quantity change means for changing an air quantity to be supplied to a dirt detection unit into a plurality of stages; a number concentration calculation unit for calculating number concentration of each particle size of fine particles detected by the dirt detection unit for each air quantity; a threshold table 22 for storing a number concentration threshold value set for each combination of the air quantity and the particle size of the fine particles; and a determination unit for performing dirt determination of each particle size by comparing calculated number concentration with the number concentration threshold value for each air quantity and particle size.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an air cleaner.

  Conventionally, the main body case has an air cleaning unit such as a filter and a blower unit such as a fan motor, and by driving the blower unit, dust or the like of air sucked from the suction port is driven by the air cleaning unit. An air cleaner that removes (collects) is known (see, for example, Patent Documents 1 and 2).

  The air cleaners of Patent Documents 1 and 2 include a dirt detection unit (a dust detector in Patent Document 2) that detects fine particles such as dust contained in the air, and the air cleaner of the blower unit is based on the detection result of the dirt detection unit. The drive is controlled.

  Such a dirt detector of an air cleaner has a light emitting element that emits light, a light receiving element that receives light, and a heating part. The dirt detection unit carries fine particles such as dust into the detection area of the light emitting element and the light receiving element by the rising air flow generated by the heating unit, irradiates the light of the light emitting element in the detection area, and from the fine particles existing in the detection area. The presence or absence of fine particles can be detected by receiving the reflected light with a light receiving element. The received signal is amplified so that it can be easily handled by a control unit such as a microcomputer.

Japanese Patent Laying-Open No. 2015-64173 JP 2002-89907 A

  By the way, in the dirt detection part of the air cleaner as described above, fine particles such as dust are carried into the detection area by the rising air flow generated by heating the heat source, and the fine particles carried into the detection area are detected. Yes.

  However, there is a problem that relatively large particles such as pollen cannot be carried into the detection area simply by heating the heat source.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an air cleaner that can improve the detection accuracy of fine particles in a dirt detection unit.

In order to solve the above problems, an air cleaner is provided in a main body case having a suction port and a blow-out port, a blower unit that sucks air from the suction port and blows out the air from the blow-out port, and the main body case. An air purifier that cleans the air that flows in from the suction port, and the main body case, and optically detects fine particles contained in the air that flows in from the suction port, according to the particle diameter of the fine particles. The dirt detection unit that outputs the output signal, the output signal of the dirt detection unit and the preset particle diameter threshold value are compared to make a dirt judgment, and the amount of air sucked by the blower and the operation of the air purifier are controlled. An air cleaner having a control unit that performs the control,
An air volume changing means for changing the air volume of the air supplied to the dirt detector in a plurality of stages, a number concentration calculator for calculating a number density for each particle diameter of the fine particles detected by the dirt detector for each air volume, By comparing the number concentration threshold calculated with the threshold value table storing the number concentration threshold set for each combination of the air volume and the particle diameter of the fine particles, and the number concentration threshold calculated for each of the air volume and the particle diameter, A determination unit for determining contamination for each particle diameter is provided.

  According to the air cleaner of the present invention, it is possible to improve the detection accuracy of fine particles in the dirt detection unit.

It is a perspective view of the air cleaner in an embodiment. It is sectional drawing of the air cleaner in the same as the above. It is a schematic block diagram of the dust sensor of an air cleaner same as the above. It is a block diagram which shows the electrical structure of the air cleaner same as the above. It is a schematic block diagram for demonstrating the arrangement | positioning aspect of the dust sensor of an air cleaner same as the above. (A)-(c) is sectional drawing of the air cleaner for demonstrating the operation | movement aspect of the air cleaner in the same as the above. (A) (b) is a graph for demonstrating the signal intensity | strength and particle diameter of the dust sensor of an air cleaner same as the above. It is explanatory drawing which shows the number density distribution curve set as a threshold value. It is explanatory drawing which shows the number density distribution curve set as a threshold value. It is a flowchart which shows a stain | pollution | contamination determination processing operation.

  Hereinafter, one embodiment of an air cleaner is described according to a drawing.

  As shown in FIG. 1, the air cleaner of the present embodiment has a substantially box-shaped main body case 1, and a suction port 2 is provided on the front side of the main body case 1. Further, a blowout port 3 is provided on the upper surface (top surface) side of the main body case 1.

  As shown in FIG.1 and FIG.2, the suction port 2 is provided with the filter 4 as an air purifying part so that attachment or detachment is possible. The filter 4 has two types of filters 4a and 4b. The filter 4a functions as a dust collecting filter that collects dust, so-called PM2.5, for example, and the filter 4b functions as a deodorizing filter that removes odors. In the main body case 1, a fan motor 5 is accommodated as a blower for blowing air flowing in from the suction port 2 through the blowout port 3.

  A front panel 6 is provided on the front side of the filter 4 so as to cover the filter 4.

  The front panel 6 can be moved in the front-rear direction by the panel actuator 6a (see FIG. 4), or only the lower end can be moved in the front-rear direction.

  A louver 7 is provided at the outlet 3 so as to be tiltable, and a tilting operation is performed by a louver actuator 7a (see FIG. 4).

  As shown in FIGS. 1 and 2, a dust sensor 8 as a dirt detection unit is provided in the main body case 1.

  More specifically, as shown in FIG. 5, the dust sensor 8 is provided in a flow path (air path) R2 different from the flow path R1 in which the filter 4 is provided. The flow path R2 in which the dust sensor 8 is provided is joined to the flow path R1 in which the filter 4 is provided on the downstream side. The fan motor 5 is housed in a merged flow path R3 where a flow path R2 in which the dust sensor 8 is provided and a flow path R1 in which the filter 4 is provided is merged. That is, since the flow path R2 in which the dust sensor 8 is provided communicates with the merging flow path R3, when the fan motor 5 operates, the air sucked from the suction port 2 flows from the flow paths R1 and R2 to the merging flow path R3. To be inhaled.

  As shown in FIGS. 3 and 4, the dust sensor 8 includes a heating unit 10 and a detection unit 11 in a sensor housing 9.

  As shown in FIG. 3, the sensor housing 9 is hollow, and includes a linear flow path forming portion 12 and two detection portions that house the detection portion 11 on both sides from the longitudinal intermediate portion of the flow path forming portion 12. The accommodating parts 13 and 14 are extended.

  An opening 12a through which air can mainly flow is formed at the base end portion (downward in FIG. 3) of the flow path forming portion 12, and mainly at the distal end portion (upward in FIG. 3) of the flow path forming portion 12. An opening 12b through which air can flow out is formed.

  The heating unit 10 is supported by a support unit (not shown) near the base end in the flow path forming unit 12.

  The heating unit 10 is configured by a resistance element, for example. That is, it is possible to generate an updraft in the sensor housing 9 by the heat of the heating unit 10 generated by supplying power to the heating unit 10. The heating unit 10 is not limited to a resistance element as long as it generates a certain amount of heat.

  Further, the two detection unit accommodating portions 13 and 14 are formed to have a three-pronged shape with the flow path forming unit 12 as a center. That is, the one detection unit accommodation unit 13 and the other detection unit accommodation unit 14 are provided so as to be positioned on the opposite sides with the flow path forming unit 12 as a center.

  The light receiving element 15 that constitutes the detection unit 11 is accommodated in one detection unit accommodation unit 13, and the light emitting element 16 that constitutes the detection unit 11 is accommodated in the other detection unit accommodation unit 14.

  As shown in FIG. 4, the detection unit 11 includes a light emitting element 16 that emits light, a light receiving element 15 that receives light and outputs a current signal according to the amount of light, and a current signal output from the light receiving element 15. Is converted to a pulse signal corresponding to the amount of fine particles and output.

  As the light emitting element 16, for example, a light emitting LED or a semiconductor laser that outputs light in one direction based on supply of power can be used. The light receiving element 15 can be a photodiode whose output current changes according to the amount of received light, for example.

  Condensing lenses 15a and 16a are arranged in the light irradiation direction of the light emitting element 16 and the light receiving direction of the light receiving element 15 to collect light so that the amount of light in the detection area Ar can be increased and finer fine particles can be detected. I have to. Since the condenser lenses 15a and 16a increase the amount of light, they can be omitted if the target detection specifications can be satisfied without being arranged.

  As shown in FIG. 4, the signal conversion unit 17 includes an amplifier circuit 18, a comparison circuit 19, and an output circuit 20.

  The amplification circuit 18 amplifies the signal output from the light receiving element 15 and outputs the amplified signal to the comparison circuit 19. The comparison circuit 19 compares the signal output from the amplifier circuit 18 with threshold values VA and VB serving as determination reference values, and outputs a pulsed signal to the output circuit 20 as a comparison result. Hereinafter, the comparison result compared with the threshold value VA is treated as an output A, and the comparison result compared with the threshold value VB is treated as an output B.

  The output circuit 20 appropriately converts the pulse signal output from the comparison circuit 19 to a voltage level that can be easily handled by the control unit 21 described later, and outputs the converted signal to the control unit 21. The heating unit 10 performs a heat generation operation based on a control signal output from the control unit 21.

  As shown in FIG. 4, the control unit 21 is electrically connected to the fan motor 5, the dust sensor 8, and the actuators 6a and 7a, and controls the air cleaner centrally by controlling each unit. It is. The control unit 21 controls each part to control the air purifier in three patterns of “odor / smoke” operation, “house dust” operation, and “pollen” operation.

  As shown in FIG. 6A, the “smell / smoke” operation moves the entire front panel 6 forward and moves the louver 7 relative to the main body case 1 when, for example, a dust sensor 8 detects fine particles of less than 2 μm. Then, the purified air is ejected in a state of being directed upward so as to be approximately 90 degrees. By such an operation, air in the entire room is sequentially taken in from the suction port 2 and odors and smoke are mainly removed by the filter 4a.

  As shown in FIG. 6B, in the “house dust” operation, for example, when the dust sensor 8 detects fine particles of 2 μm or more and less than 10 μm, the front panel 6 is moved forward only under the front panel 6. While being tilted, air purified in a state where the louver 7 is approximately 45 degrees with respect to the main body case 1 is ejected. By such an operation, air staying from the suction port 2 especially from the middle in the height direction to the lower part is taken in sequentially, and house dust that tends to stay in the region is mainly removed by the filter 4a.

  As shown in FIG. 6 (c), for example, when the dust sensor 8 detects fine particles of 10 μm or more in the dust sensor 8, the front panel 6 is tilted by moving only the lower part of the front panel 6 forward, The fan motor 5 is driven in a state where the louver 7 is approximately 30 degrees with respect to the main body case 1. By such an operation, air staying in the vicinity of the floor in the room in particular is sequentially taken in from the suction port 2, and pollen that tends to stay in the area is mainly removed by the filter 4a.

Moreover, in the air cleaner of this embodiment, as shown in FIGS. 4 and 5, the flow path R2 provided with the dust sensor 8 is in communication with the merge flow path R3 as described above. By controlling the rotational speed (output) of the fan motor 5, the wind speed (air volume) in the flow path R2 can be changed. In addition, the minimum air volume in the blower outlet 3 at the time of the drive of the fan motor 5 is 1.1 m < ³ > / min, and the maximum air volume is set to 8.7 m < ³ > / min.

  As shown in FIG. 3, the air volume introduced into the flow path forming unit 12 from the opening 12a of the dust sensor 8 is set to about 1/10 of the air volume of the outlet 3 shown in FIG. The control unit 21 shown in FIG. 2 recognizes the air volume per unit time introduced into the dust sensor 8 based on the rotational speed of the fan motor 5.

  Next, the change in the detection signal due to the difference in the air volume will be described with reference to FIGS.

  7A and 7B show the signal intensity (receiver signal) of the light receiving element 15 (see FIG. 3) and the pulse output waveform output to the control unit 21 (see FIG. 4) due to the difference in particle diameter. It is shown. The detection signal S1 in FIGS. 7 (a) and 7 (b) indicates the signal intensity when a fine particle having a particle diameter of about 1 μm and 1 μm or more is detected. The detection signal S2 in FIGS. 7 (a) and 7 (b) indicates the signal intensity when a fine particle having a particle diameter of about 2 μm and 2 μm or more is detected. The detection signal S3 in FIGS. 7 (a) and 7 (b) indicates the signal intensity when a fine particle having a particle diameter of about 8 μm and 8 μm or more is detected. The detection signal S4 in FIGS. 7A and 7B indicates the signal intensity when a fine particle having a particle diameter of about 10 μm and 10 μm or more is detected.

  FIG. 7 (a) shows the signal intensity of the light receiving element 15 at the air volume W1 where the air volume of the fan motor 5 is the smallest and the waveform of the pulse output associated therewith. FIG. 7B shows the signal intensity of the light receiving element 15 in the air volume W2 in which the air volume of the fan motor 5 is larger than the air volume W1, and the pulse output waveform associated therewith.

  As can be seen from FIGS. 7A and 7B, the larger the particle size of the fine particles, the higher the signal intensity in the light receiving element 15, and the longer the signal output time. Further, as can be seen by comparing FIG. 7 (a) and FIG. 7 (b), even if the particle diameter of the microparticles to be detected is the same, the signal intensity is different if the air volume is different. More specifically, even if the particle diameters of the fine particles are the same, if the air volume is small, the light emitted from the light emitting element 16 surely hits the fine particles and is reflected, so that the signal intensity increases.

  For this reason, in the present embodiment, the threshold value VB is used as a determination criterion for determining whether the fine particles to be detected are less than 2 μm or 2 μm or more in the state of the air volume W1, which is the smallest air volume, and similarly less than 1 μm or 1 μm. A criterion for determining whether or not the above is set as the threshold value VA. Here, the threshold value VB is a criterion for determining whether the particle diameter is less than 10 μm or more than 10 μm in the state of the air volume W2, and the threshold value VA is whether the particle diameter is less than 2 μm or more than 2 μm in the state of the air volume W2. It is set as a criterion for determination. Here, the comparison circuit 19 (see FIG. 4) outputs an off signal as the output A when the threshold value VA is below, and an on signal as the output A when the threshold value VA or more. Further, the comparison circuit 19 outputs an off signal as the output B when it is below the threshold VB, and an on signal as the output B when it is equal to or higher than the threshold VB.

  That is, the control unit 21 can determine the particle diameter of the fine particles from the states of the output A and the output B and the air volume. More specifically, it is as follows.

  When the output A and the output B are both off in the case of the air volume W1, the control unit 21 determines that there is no fine particle or the particle diameter is less than 1 μm. The control unit 21 (see FIG. 4) determines that the particle diameter of the fine particles is 1 μm or more and less than 2 μm when the output A is in the on state and the output B is in the off state in the case of the air volume W1. The control unit 21 (see FIG. 4) determines that the particle diameter of the fine particles is 2 μm or more when both the output A and the output B are on in the case of the air volume W1.

  The controller 21 (see FIG. 4) determines that the output A and the output B are both less than 2 μm when the air volume W2 is off. The control unit 21 (see FIG. 4) determines that the particle diameter of the fine particles is 2 μm or more and less than 10 μm when the output A is in the on state and the output B is in the off state in the case of the air volume W2. The control unit 21 (see FIG. 4) determines that the particle diameter of the fine particles is 10 μm or more when both the output A and the output B are on in the case of the air volume W2.

  Based on the determination operation as described above, the control unit 21 can recognize the number and particle size of fine particles detected per unit time in the air volumes W1 and W2 based on the outputs A and B of the dust sensor 8. .

  Then, based on the detection result of the fine particles, the control unit 21 performs, for example, five levels of dirt determination, and displays the determination result as, for example, five levels of dirt on a display unit provided above the front panel 6.

  On the other hand, if the amount of air introduced into the dust sensor 8 is different, the number of particles detected per unit time increases as the amount of air increases even if the concentration of the particles present in the indoor space is the same. Therefore, when the stain determination is performed based on the number of fine particles detected per unit time, the stain level increases as the air volume increases, and accurate stain determination cannot be performed.

  Further, when the air volume introduced into the dust sensor 8 is increased, the fine particles detected at the output B are detected only at the output A as shown in FIGS. 7A and 7B. There is a possibility that the particle diameter cannot be accurately determined and the louver 7 cannot be optimally controlled.

  Therefore, in this embodiment, in order to determine the dirt level, the control unit 21 has a function of calculating the number concentration of the detected fine particles and, as shown in FIG. The threshold value table 22 storing the threshold value for determining the number density is provided. Then, the contamination level is determined by comparing the number concentration of the fine particles with the threshold value of the number concentration.

  More specifically, in FIG. 8, distribution curves X1 and X2 indicate the distribution of signal intensity per suction flow rate when the dust sensor 8 detects fine particles having a particle diameter of 2 μm having a predetermined concentration q1 in the air volumes W1 and W2, respectively. ing. The area of the region surrounded by the distribution curves X1 and X2 is proportional to the number (abundance) of fine particles. Here, a description will be given using the distribution curve X1. A region surrounded by the upper side of the straight line indicating the threshold value VB and the distribution curve X1 is a region S1, and a region surrounded by the lower side of the straight line indicating the threshold value VB and the distribution curve X1 is S2. The number of fine particles represented by the area of the region S1 corresponds to the number of fine particles having a particle diameter of 2 μm exceeding the threshold value VB at a predetermined concentration q1. The number of fine particles represented by the area of the region S2 corresponds to the number of fine particles having a particle diameter of 2 μm that did not exceed the threshold value VB at a predetermined concentration q1. That is, the dust sensor 8 detects a fine particle having a particle diameter of 2 μm as a particle diameter of less than 2 μm at a ratio of S2 / (S1 + S2). Therefore, when the contamination level (of fine particles having a particle diameter of 2 μm) determined as an air cleaner is the concentration q1, the threshold value corresponding to the contamination level (the count number of the output B) can be expressed using the distribution curve X1. . That is, when the count number of the output B output from the dust sensor 8 (the count number exceeding the threshold value VB) is equal to or greater than the number of fine particles represented by the area of the region S1, the air particles to be measured are measured. It is determined that the concentration of the fine particles having a diameter of 2 μm has reached the concentration q1 or more. The distribution curve X2 shows a case where the air volume W1 is increased to the air volume W2, and the distribution of the number concentration of fine particles of 2 μm slides to the threshold value VA side. These distribution curves X1 and X2 are stored in the threshold value table 22 as threshold values for performing the dirt determination at the respective air volumes W1 and W2. Further, by storing a distribution curve representing a density other than the predetermined density q1 in the threshold value table 22, it is possible to determine another contamination level. These distribution curves X1 and X2 are distribution curves obtained from experiments.

  Similarly, in FIG. 9, distribution curves X3 and X4 indicate signal intensity distributions when the dust sensor 8 detects fine particles having a predetermined diameter q2 and a particle diameter of 1 μm in the air volumes W1 and W2, respectively. The distribution curve X4 shows the case where the air volume W1 is increased to the air volume W2, and the distribution of the number concentration of 1 μm fine particles slides to the threshold value VA side. These distribution curves X3 and X4 are stored in the threshold value table 22 as threshold values for performing the dirt determination at the respective air volumes W1 and W2. These distribution curves X3 and X4 are distribution curves obtained from experiments.

  In the present embodiment, the case of particles having a particle diameter of 1 μm and 2 μm has been described. However, the same threshold value is applied to other particle diameters, for example, fine particles having a particle diameter exceeding 5 μm and fine particles exceeding 8 μm. Can be set.

  Next, the operation (one operation example) of the air cleaner formed as described above will be described.

  In the air cleaner of the present embodiment, the operation unit is operated by the user, and the control unit 21 controls the driving of the fan motor 5 based on the operation.

  Further, the control unit 21 operates the air purifier by any one of the “odor / smoke” operation, the “house dust” operation, and the “pollen” operation depending on the particle size difference of the fine particles detected by the dust sensor 8. It is like that.

  In parallel with the cleaning operation as described above, an operation for determining the contamination level of the fine particles having the particle diameters of 2 μm and 1 μm will be described with reference to FIG.

  When the air cleaning operation is started (step 1), the control unit 21 detects the outputs A and B of the dust sensor 8 (step 2), and sets the number of pulses of the outputs A and B for a predetermined time set in advance. Count (step 3).

  Next, the operations in steps 2 and 3 are performed for each of the air volumes W1 and W2, and the number concentration of the fine particles output as pulse signals of outputs A and B is calculated based on the integrated number of pulses and the air volume within a predetermined time. (Step 4).

  Next, distribution curves X1, X2, X3, and X4, which are threshold values for the air volumes W1 and W2, are read from the threshold table 22 (step 5).

  Hereinafter, the expression “exceeds the distribution curve xx” means that the count number (output A or output B) exceeding the threshold is the distribution curve xx having a predetermined concentration stored in the threshold table 22. That is, the number of particles represented by a region surrounded by a straight line indicating the corresponding threshold value is exceeded.

  Next, it is determined whether or not the number density calculated in step 4 exceeds the distribution curve X1 in a range exceeding the threshold value VB (step 6). That is, the number corresponding to the area surrounded by the distribution curve X1 indicating the distribution of the predetermined density and the upper side of the threshold value VB is compared with the count number of the output B. If the number density exceeds the distribution curve X1 in the range exceeding the threshold value VB, the process proceeds to step 7 to determine whether or not the number density exceeds the distribution curve X2 in the range exceeding the threshold value VA.

  If the number concentration exceeds the distribution curve X2 in step 7, the process proceeds to step 8 where it is determined that the fine particles having a particle diameter of 2 μm exceed a predetermined contamination level and displayed on the display unit. Return to.

  When the number density does not exceed the distribution curve X1 in the range where the number density exceeds the threshold value VB in step 6, and when the number density does not exceed the distribution curve X2 in step 7, the process proceeds to step 9 and the number density is set to the threshold value. It is determined whether or not the distribution curve X3 is exceeded in a range exceeding VA. If the number concentration exceeds the distribution curve X3 in a range exceeding the threshold value VA, it is determined that the fine particle having a particle diameter of 1 μm exceeds a predetermined level of dirt and displayed on the display unit (step 10). Return to step 1.

  In step 9, when the number concentration does not exceed the distribution curve X3 in the range exceeding the threshold value VA, it is determined that the fine particles having the particle diameters of 2 μm and 1 μm do not exceed the predetermined dirt level and displayed on the display unit. (Step 11), the process returns to step 1.

  Further, the louver 7 is controlled to an optimum angle based on the determination results of Step 8, Step 10 and Step 11.

  Even for fine particles having a particle diameter of 5 μm and 10 μm, the threshold value table 22 is provided with a similar distribution curve as a threshold value, and the same determination as described above can be performed.

  In the air cleaner as described above, the following effects can be obtained.

  (1) The dust sensor 8 as a dirt detection unit is disposed on a flow path R2 of air generated in association with driving of the fan motor 5 as a blower unit. The control unit 21 changes the wind speed in the detection area Ar of the dust sensor 8 by changing the rotation speed (output) of the fan motor 5. By arranging the dust sensor 8 on the air flow path R <b> 2 generated when the fan motor 5 is driven in this way, the particle size of the large particle diameter that cannot be reached in the detection region Ar only by the rising airflow of the heating unit 10. The fine particles can easily reach the detection area Ar by the fan motor 5. Further, the focus of the particle diameter of the fine particles in the dust sensor 8 can be shifted using the change in the signal intensity of the detection signal in the dust sensor 8 that is generated by changing the rotation speed of the fan motor 5. As a result, the detection accuracy of the fine particles can be increased.

  (2) Since the number concentration of the fine particles detected by the dust sensor 8 is detected and compared with the number concentration threshold, the accuracy of the dirt determination does not decrease even if the amount of air supplied to the dust sensor 8 is changed.

  (3) Since the distribution curves X1 to X4 for each particle diameter and air volume stored in the threshold value table 22 are used as threshold values and compared with the detected number concentration, the accuracy of stain determination can be improved.

  (4) By comparing the change in the number concentration of fine particles and the change in the particle diameter with the change in the air volume with the distribution curves X1 to X4 set in advance as threshold values for each region divided by the threshold values VA and VB, And the number concentration can be accurately detected. Therefore, it is possible to improve the accuracy of the dirt determination for each particle diameter divided by the threshold values VA and VB.

  In addition, you may change the said embodiment as follows.

  If the threshold values VA and VB for determining the particle diameter are set in more stages and more types of distribution curves based on the combination of the air volume and the particle diameter are prepared, the accuracy of determining the particle diameter can be further improved.

  As described above, since the air cleaner according to the present invention can improve the detection accuracy of the particulates in the dust sensor, the above configuration can be applied when the dust sensor is used in, for example, another air conditioner.

1 Body Case 2 Suction Port 3 Blowout Port 4 Filter (Air Cleaner)
5 Fan motor (air blower, air volume changing means)
7 Louver 8 Dust sensor (dirt detector)
21 Control unit (air volume changing means, number concentration calculation unit, determination unit)
22 Threshold Table VA Threshold VB Threshold X1 to X4 Number density threshold.

Claims (4)

A main body case having a suction port and a blowout port;
A blower unit that sucks air from the suction port and blows it out of the blowout port;
An air purifier provided in the main body case for purifying air flowing in from the suction port;
A dirt detector provided in the body case for optically detecting fine particles contained in the air flowing from the suction port and outputting an output signal corresponding to the particle diameter of the fine particles;
An air cleaner having a control unit that compares the output signal of the dirt detection unit with a preset particle size threshold value to make a dirt judgment and controls the amount of air sucked by the blower and the operation of the air cleaner. There,
The controller is
An air volume changing means for changing the air volume of the air supplied to the dirt detector in a plurality of stages;
A number concentration calculation unit for calculating a number concentration for each particle diameter of the fine particles detected by the dirt detection unit for each air volume;
A threshold table storing a number concentration threshold set for each combination of the air volume and the particle size of the fine particles;
An air cleaner comprising: a determination unit configured to determine a contamination for each particle diameter by comparing the calculated number concentration and the number concentration threshold for each of the air volume and the particle diameter.   2. The determination unit according to claim 1, wherein the determination unit compares the change in the number concentration and the particle diameter of the fine particles accompanying the change in the air volume with the number concentration threshold for each region divided by the particle diameter threshold. Air cleaner.   The particle size threshold value is set in the threshold value table in at least two stages, and the number concentration threshold value is set for each combination of the air volume in the plurality of stages and the region divided by the particle diameter threshold value. Item 2. The air cleaner according to Item 1. The controller performs at least one level of dirt determination;
The air cleaner according to any one of claims 1 to 3, wherein the threshold value table uses a distribution curve of an output signal of the dirt detection unit at a number concentration corresponding to the level.

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