air purifier

Abstract

To provide an air cleaner that enables appropriate filter replacement in accordance with a situation, the air cleaner having a plurality of independent flow passages.SOLUTION: An air cleaner 1 includes a first air flow passage 20 and a second air flow passage 30 which are independent of each other. The first air flow passage 20 includes a first filter 21, a first fan 22 and a first differential pressure sensor 23 that detects a first pressure difference between an upstream side and a downstream side of the first filter 21. The second air flow passage 30 includes a second filter 31, a second fan 32 and a second differential pressure sensor 33 that detects a second pressure difference between an upstream side and a downstream side of the second filter 31. The air cleaner 1 includes a control section that controls the first fan 22 and the second fan 32. When one of the first pressure difference and the second pressure difference reaches a reference pressure difference or greater, the control section controls rotational frequency of at least one of the first fan 22 and the second fan 32 so as to reduce the difference between the first pressure difference and the second pressure difference.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an air cleaner.

Background Art

[0002] Patent Document 1 discloses a filter replacement estimation device that estimates the replacement timing of a mounted filter.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to the filter replacement estimation device of Patent Document 1, the shortest replacement prediction time and the longest replacement prediction time are obtained, and the air supply amount from the air supply outlet corresponding to the filter with a long prediction time until the replacement timing increases, and the air supply amount from the air supply outlet corresponding to the filter with a short prediction time decreases, so that air conditioning control is performed to match the filter replacement timing.

[0005] However, the filter replacement estimation device of Patent Document 1 describes air conditioning control of the air supply amount and filter replacement for a plurality of filters provided in a single same air flow path, but does not describe, for example, filter air conditioning control and filter replacement for a device having a plurality of independent air flow paths. Therefore, there is room for improvement in filter replacement for a device having a plurality of air flow paths for air conditioning.

[0006] Therefore, an object of the present invention is to provide an air cleaner capable of appropriately performing filter replacement according to the situation in an air cleaner having a plurality of independent flow paths.

Means for Solving the Problems

[0007] An air purifier according to one aspect of the present invention is, An air purifier having at least a first flow path and a second flow path that are independent of each other, The first filter and first fan are provided in the first flow path, The second filter and second fan are provided in the second flow path, A differential pressure sensor detects a first pressure difference, which is the pressure difference between the upstream pressure and the downstream pressure in the first filter, and a second pressure difference, which is the pressure difference between the upstream pressure and the downstream pressure in the second filter. A control unit that controls the first and second fans, It has, When the pressure difference between the first pressure difference or the second pressure difference exceeds a reference value, the control unit controls the rotation speed of at least one of the first fan and the second fan so as to reduce the difference between the first pressure difference and the second pressure difference. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an air purifier equipped with multiple independent flow paths that allows for appropriate filter replacement depending on the situation. [Brief explanation of the drawing]

[0009] [Figure 1] This is a perspective view of an air purifier according to an embodiment of the present invention. [Figure 2] This is a front cross-sectional view showing the internal structure of an air purifier. [Figure 3] This is a flowchart explaining the operation of an air purifier. [Figure 4] This is a flowchart explaining the operation of an air purifier. [Figure 5] This graph shows the relationship between the filter's aperture ratio and the airflow reduction rate of the air purifier. [Figure 6] This graph shows the relationship between the filter's aperture ratio and the rate of increase in pressure loss (pressure difference). [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings. For the sake of clarity, the description of components having the same reference numeral as those already described in the description of the embodiments will be omitted. Furthermore, the dimensions of the components shown in these drawings may differ from the actual dimensions of the components for the sake of clarity.

[0011] Figure 1 is a perspective view showing an example of an air purifier according to an embodiment of the present invention. Figure 2 is a cross-sectional view of the air purifier shown in Figure 1 along line AA. As shown in Figures 1 and 2, the air purifier 1 of this embodiment is a vertical type air purifier that can be used, for example, by being erected on the floor.

[0012] The air purifier 1 has a box-shaped housing 10 that is long in the vertical direction. A front panel 11 is attached to the front side of the housing 10 so as to cover the front. An operating unit 12 for controlling the operating status of the air purifier 1 is provided on the upper part of the front panel 11. A control unit 13 for controlling the operation of the air purifier 1 is provided on the back side of the front panel 11. The operating unit 12 is connected to the control unit 13.

[0013] Air intake ports 14 are provided on both the left and right sides of the housing 10 to draw outside air into the housing 10. In the example shown in the figure, a first air intake port 14A is provided on the left side of the housing 10, and a second air intake port 14B is provided on the right side.

[0014] An outlet 15 is provided on the top surface of the housing 10 for blowing out the air inside the housing 10, i.e., purified air, to the outside. The outlet 15 includes a first outlet 15A that blows out the air drawn in from the first intake port 14A, and a second outlet 15B that blows out the air drawn in from the second intake port 14B.

[0015] Inside the housing 10, an air flow path through which the air sucked into the housing 10 passes is provided. In the example shown in the figure, a first air flow path 20 communicating between the first suction port 14A and the first blowout port 15A, and a second air flow path 30 communicating between the second suction port 14B and the second blowout port 15B are provided. The air sucked into the housing 10 from the first suction port 14A does not pass through the second air flow path 30. Similarly, the air sucked into the housing 10 from the second suction port 14B does not pass through the first air flow path 20.

[0016] At the air inlet of the first air flow path 20, that is, the first suction port 14A, a first filter 21 is provided. The first filter 21 is a filter for purifying the air sucked into the housing 10 from the first suction port 14A, and is provided in the first air flow path 20 so as to face the outside of the housing 10 at the first suction port 14A.

[0017] At the air inlet of the second air flow path 30, that is, the second suction port 14B, a second filter 31 is provided. The second filter 31 is a filter for purifying the air sucked into the housing 10 from the second suction port 14B, and is provided in the second air flow path 30 so as to face the outside of the housing 10 at the second suction port 14B.

[0018] The first filter 21 and the second filter 31 are dust collection filters for removing dust, dirt, etc. from the air. For example, a HEPA (High Efficiency Particulate Air) filter is used.

[0019] In the first air passage 20, a first fan 22 is provided downstream of the first filter 21. The first fan 22 is a fan that draws air into the first air passage 20 from outside the housing 10 through the first intake port 14A and blows the drawn-in air through the first air passage 20 to the first outlet port 15A. The first fan 22 is provided with a drive motor (not shown) for driving the first fan 22. The drive motor of the first fan 22 is connected to the control unit 13. The first fan 22 is configured as, for example, a sirocco fan.

[0020] In the second air passage 30, a second fan 32 is provided downstream of the second filter 31. The second fan 32 is a fan that draws air into the second air passage 30 from outside the housing 10 through the second intake port 14B and blows the drawn-in air through the second air passage 30 to the second outlet port 15B. The second fan 32 is provided with a drive motor (not shown) for driving the second fan 32. The drive motor of the second fan 32 is connected to the control unit 13. The second fan 32 is configured as, for example, a sirocco fan.

[0021] The first air passage 20, in which the first filter 21 is located, is equipped with a first differential pressure sensor 23 for detecting the first pressure difference, which is the pressure difference between the pressure upstream and downstream of the first filter 21 in the first air passage 20. The second air passage 30, in which the second filter 31 is located, is equipped with a second differential pressure sensor 33 for detecting the second pressure difference, which is the pressure difference between the pressure upstream and downstream of the second filter 31 in the second air passage 30. The first pressure difference is the pressure loss occurring in the first filter 21, and is the pressure difference between the pressure value detected by the first differential pressure sensor 23 and the ambient pressure. The second pressure difference is the pressure loss occurring in the second filter 31, and is the pressure difference between the pressure value detected by the second differential pressure sensor 33 and the ambient pressure. The first differential pressure sensor 23 and the second differential pressure sensor 33 are connected to the control unit 13.

[0022] The control unit 13 controls the operation of the first fan 22 and the second fan 32 according to the operation signals output based on the operation of the operation unit 12. The control unit 13 also controls the rotation speed of the drive motors of the first fan 22 and the second fan 32 based on the first pressure difference detected by the first differential pressure sensor 23 and the second pressure difference detected by the second differential pressure sensor 33. Specifically, when one of the pressure differences, either the first or the second, exceeds a preset reference value, the control unit 13 controls the rotation speed of at least one of the drive motors of the first fan 22 and the second fan 32 so that the difference between the first and second pressure differences decreases. For example, when one of the pressure differences, either the first or the second, exceeds a reference value, the control unit 13 controls the rotation speed of the drive motor of the fan whose pressure difference exceeds the reference value to decrease, and the rotation speed of the drive motor of the fan whose pressure difference does not exceed the reference value to increase. Furthermore, the control unit 13 may, for example, control the fan drive motor to decrease only the rotation speed of the fan whose pressure difference exceeds the reference value when either the first or second pressure difference exceeds the reference value, or control the fan drive motor to increase only the rotation speed of the fan whose pressure difference does not exceed the reference value. The control unit 13 can control the first fan 22 and the second fan 32 individually.

[0023] Thus, in the air purifier 1, the first air passage 20 having a first intake port 14A, a first outlet port 15A, a first filter 21, and a first fan 22, and the second air passage 30 having a second intake port 14B, a second outlet port 15B, a second filter 31, and a second fan 32 are provided as independent air passages. Furthermore, the first air passage 20 and the second air passage 30 are provided as air passages having a symmetrical structure partitioned in the center of the housing 10.

[0024] Next, an example of the operation of the air purifier 1 will be explained with reference to the flowcharts shown in Figures 3 and 4. First, we will explain the operation of air purifier 1 as it is when it leaves the factory, referring to Figure 3. During manufacturing at the factory, the air purifier 1 is initially configured for the first pressure difference of the first filter 21 and the second pressure difference of the second filter 31 in the first air passage 20 and the second air passage 30.

[0025] Specifically, the control unit 13 of the air purifier 1 stores the first initial pressure difference PI1 as the initial value (P1initial) for the first pressure difference of the first filter 21, and the second initial pressure difference PI2 as the initial value (P2initial) for the second pressure difference of the second filter 31 (step S11). The first initial pressure difference PI1 and the second initial pressure difference PI2 are values ​​that are stored in advance as the pressure difference between the first filter 21 and the second filter 31 in an unused state. The first initial pressure difference PI1 and the second initial pressure difference PI2 are provided for each operating mode of the air purifier 1. The operating modes of the air purifier 1 are provided by differences in the rotation speed of the fan drive motor (hereinafter also referred to as the fan rotation speed), for example, a high-speed operating mode, a medium-speed operating mode, and a low-speed operating mode. Furthermore, the first initial pressure difference PI1 and the second initial pressure difference PI2 are set to 65 Pa in high-speed operation mode, 50 Pa in medium-speed operation mode, and 40 Pa in low-speed operation mode.

[0026] Furthermore, the control unit 13 sets the first limit pressure difference PL1 as the limit value (P1limit) for the first pressure difference of the first filter 21, and the second limit pressure difference PL2 as the limit value (P2limit) for the second pressure difference of the second filter 31 (step S12). The first limit pressure difference PL1 and the second limit pressure difference PL2 are the pressure loss limits of the first filter 21 and the second filter 31, that is, the replacement thresholds for the first and second pressure differences that indicate when it is time to replace the first filter 21 and the second filter 31. The limit values ​​of the first limit pressure difference PL1 and the second limit pressure difference PL2 are set to, for example, twice the initial values ​​of the first initial pressure difference PI1 and the second initial pressure difference PI2. That is, the first limit pressure difference PL1 and the second limit pressure difference PL2 are set to 130 Pa in high-speed operation mode, the first limit pressure difference PL1 and the second limit pressure difference PL2 are set to 100 Pa in medium-speed operation mode, and the first limit pressure difference PL1 and the second limit pressure difference PL2 are set to 80 Pa in low-speed operation mode.

[0027] Furthermore, the control unit 13 initializes the first reference pressure difference PB1 as the reference value (P1base) for the first pressure difference of the first filter 21, and the second reference pressure difference PB2 as the reference value (P2base) for the second pressure difference of the second filter 31 (step S13). The first reference pressure difference PB1 and the second reference pressure difference PB2 are target pressure difference values ​​set to synchronize the replacement timing of the first filter 21 and the second filter 31, and are target pressure difference values ​​that serve as a guideline when adjusting the rotation speed of the first fan 22 and the second fan 32. The first reference pressure difference PB1 and the second reference pressure difference PB2 are calculated by P(1 or 2)base = P(1 or 2)initial + P(1 or 2)initial × 10%. As shown in step S11, the first initial pressure difference PI1 and the second initial pressure difference PI2 are set, so the initial settings for the first reference pressure difference PB1 and the second reference pressure difference PB2 are set as follows: 71.5 (65 + 6.5) Pa for high-speed operation mode, 55 (50 + 5) Pa for medium-speed operation mode, and 44 (40 + 4) Pa for low-speed operation mode.

[0028] Next, the operation of the air purifier 1 after it leaves the factory will be explained with reference to Figure 4. As described above, the air purifier 1 will operate as follows when the control unit 12 is operated and the unit enters operation mode, for example, after being shipped from the factory. In this example, we will explain assuming that the air purifier 1 is operating in high-speed mode.

[0029] The control unit 13 measures the first pressure difference P1, which is the current pressure difference in the first filter 21, and the second pressure difference P2, which is the current pressure difference in the second filter 31 (step S21).

[0030] Next, the control unit 13 determines whether the current first pressure difference P1 or second pressure difference P2 measured in step S21 is less than 65 Pa, which is the first initial pressure difference PI1 of the first filter 21 and the second initial pressure difference PI2 of the second filter 31 stored in step S11 (step S22).

[0031] In step S22, if the first pressure difference P1 or the second pressure difference P2 is smaller than the first initial pressure difference PI1 and the second initial pressure difference PI2 (step S22: Yes), the control unit 13 determines that there is a defect in the air purifier 1 and notifies the user of a device error (step S23). The device error is notified, for example, by displaying text or a lamp on the operation unit 12. Examples of cases in which a device error is notified in step S23 include forgetting to install the first filter 21 or the second filter 31 in the air purifier 1, or damage to the first filter 21 or the second filter 31.

[0032] In step S22, if the first pressure difference P1 or the second pressure difference P2 is not smaller than the first initial pressure difference PI1 and the second initial pressure difference PI2 (step S22: No), the control unit 13 determines whether the measurement of the first pressure difference P1 and the second pressure difference P2 in step S21 is the first measurement (step S24). The first measurement includes, for example, the measurement taken when a user who has purchased the air purifier 1 uses it for the first time, or the measurement taken when the air purifier 1 is first started after the filter has been replaced.

[0033] In step S24, if the measurement of the first pressure difference P1 and the second pressure difference P2 is the first measurement (step S24: Yes), the control unit 13 determines whether the first pressure difference P1 or the second pressure difference P2 is greater than 130 Pa, which is the first limit pressure difference PL1 of the first filter 21 and the second limit pressure difference PL2 of the second filter 31 set in step S12 (step S25).

[0034] In step S25, if the first pressure difference P1 or the second pressure difference P2 is greater than the first limit pressure difference PL1 and the second limit pressure difference PL2 (step S25: Yes), the control unit 13 determines that there is a defect in the air purifier 1 and notifies the user of a device error (step S26). The device error is notified, for example, by displaying text or a lamp on the operation unit 12. An example of a device error notified in step S26 is forgetting to remove the packaging from the first filter 21 or the second filter 31 attached to the air purifier 1.

[0035] In step S25, if the first pressure difference P1 or the second pressure difference P2 is not greater than the first limit pressure difference PL1 and the second limit pressure difference PL2 (step S25: No), the control unit 13 determines whether the first pressure difference P1 or the second pressure difference P2 is 71.5 Pa or greater, which is the first reference pressure difference PB1 of the first filter 21 and the second reference pressure difference PB2 of the second filter 31 that were initially set in step S13 (step S27).

[0036] In step S27, if the first pressure difference P1 or the second pressure difference P2 is not equal to or greater than the first reference pressure difference PB1 and the second reference pressure difference PB2 (71.5 Pa) (step S27: No), the control unit 13 returns to step S21 at the rotational speed of the first fan 22 and the second fan 32 immediately before (step S28), that is, while maintaining the current rotational speed, and measures the first pressure difference P1 of the first filter 21 and the second pressure difference P2 of the second filter 31.

[0037] In step S27, if the first pressure difference P1 or the second pressure difference P2 is greater than or equal to the first reference pressure difference PB1 and the second reference pressure difference PB2 (71.5 Pa) (step S27: Yes), the control unit 13 changes the reference values, i.e., changes the first reference pressure difference PB1 and the second reference pressure difference PB2 (pressure difference target values) (step S29). The changed first reference pressure difference PB1 and the second reference pressure difference PB2 are calculated by P(1 or 2) base = P(1 or 2) base + P(1 or 2) initial × 10%. In other words, the changed first reference pressure difference PB1 and the second reference pressure difference PB2 are the current first reference pressure difference PB1 or the second reference pressure difference PB2 plus an increase equivalent to 10% of the first initial pressure difference PI1 or the second initial pressure difference PI2. Since the current first reference pressure difference PB1 and second reference pressure difference PB2 are 71.5 Pa, the revised first reference pressure difference PB1 and second reference pressure difference PB2 will be 78(71.5 + 6.5) Pa.

[0038] Next, the control unit 13 controls the fan to increase the rotation speed of the fan whose pressure difference (either the first pressure difference P1 or the second pressure difference P2) is not equal to the first reference pressure difference PB1 or the second reference pressure difference PB2 (71.5 Pa) (step S30). Next, the control unit 13 controls the fan to decrease the rotation speed of the fan whose pressure difference (either the first pressure difference P1 or the second pressure difference P2) is equal to or greater than the first reference pressure difference PB1 or the second reference pressure difference PB2 (71.5 Pa) (step S31). Then, the control unit 13 returns to step S21 and measures the first pressure difference P1 of the first filter 21 and the second pressure difference P2 of the second filter 31. This controls the fan to reduce the difference between the first pressure difference of the first fan 22 and the second pressure difference of the second fan 32.

[0039] On the other hand, in step S24, if the measurement of the first pressure difference P1 and the second pressure difference P2 is not the first measurement (step S24: No), the control unit 13 determines whether the first pressure difference P1 or the second pressure difference P2 measured this time is lower than the previously measured pressure difference (step S32).

[0040] In step S32, if the first pressure difference P1 or the second pressure difference P2 measured this time is lower than the previously measured pressure difference (step S32: Yes), the control unit 13 performs a conversion of the reference values, i.e., a conversion of the first reference pressure difference PB1 and the second reference pressure difference PB2 (pressure difference target value) (step S33). An example of when the first pressure difference P1 or the second pressure difference P2 is lower than the previously measured pressure difference is when the first filter 21 or the second filter 31 attached to the air purifier 1 has been cleaned. The first reference pressure difference PB1 and the second reference pressure difference PB2 after conversion are calculated by P(1 or 2)base = P(1 or 2) + P(1 or 2)initial × 10%. That is, the first reference pressure difference PB1 and the second reference pressure difference PB2 after conversion are the first pressure difference P1 or the second pressure difference P2 measured this time plus an increase equivalent to 10% of the first initial pressure difference PI1 or the second initial pressure difference PI2.

[0041] Then, the control unit 13 determines whether the first pressure difference P1 or the second pressure difference P2 measured this time is greater than 130 Pa, which is the first limit pressure difference PL1 of the first filter 21 and the second limit pressure difference PL2 of the second filter 31 set in step S12 (step S34).

[0042] On the other hand, in step S32, if the first pressure difference P1 or the second pressure difference P2 measured this time is not lower than the previously measured pressure difference (step S32: No), the control unit 13 proceeds directly to step S34 and determines whether the first pressure difference P1 or the second pressure difference P2 is greater than 130 Pa, which is the first limit pressure difference PL1 of the first filter 21 and the second limit pressure difference PL2 of the second filter 31.

[0043] In step S34, if the first pressure difference P1 or the second pressure difference P2 is greater than the first limit pressure difference PL1 and the second limit pressure difference PL2 (step S34: Yes), the control unit 13 determines that the filter's purification capacity has decreased and notifies the user to replace the filter (step S35).

[0044] In step S34, if the first pressure difference P1 or the second pressure difference P2 is not greater than the first limit pressure difference PL1 and the second limit pressure difference PL2 (step S34: No), the control unit 13 proceeds to step S27 to determine whether the first pressure difference P1 or the second pressure difference P2 is greater than or equal to the currently set first reference pressure difference PB1 and second reference pressure difference PB2. The currently set first reference pressure difference PB1 and second reference pressure difference PB2 include the reference values ​​initially set in step S13, the reference values ​​changed in step S29, and the reference values ​​converted in step S33.

[0045] In step S27, if the first pressure difference P1 or the second pressure difference P2 is not equal to or greater than the first reference pressure difference PB1 and the second reference pressure difference PB2 (step S27: No), the control unit 13, if the reference values ​​were converted in step S33, sets the rotational speed of the first fan 22 and the second fan 32 to the initial rotational speed at the start of operation; otherwise, if the reference values ​​were not converted in step S33, it sets the rotational speed of the first fan 22 and the second fan 32 to the previous rotational speed (step S28) and returns to step S21.

[0046] In step S27, if the first pressure difference P1 or the second pressure difference P2 is greater than or equal to the first reference pressure difference PB1 and the second reference pressure difference PB2 (step S27: Yes), the control unit 13 changes the reference value in step S29. As described above, the change in the reference value is calculated by P(1 or 2)base = P(1 or 2)base + P(1 or 2)initial × 10%. Therefore, each time the reference value is changed, 10% of the initial pressure difference is added to the previously set reference value, and the reference value gradually becomes larger. Specifically, in the high-speed operation mode of this example, the reference value increases by 6.5 Pa each time, such as 71.5 Pa, 78 Pa, 84.5 Pa, and 91 Pa. In other words, the increase in the reference value is a constant 6.5 Pa, but each time it is changed, the ratio of the increase in pressure difference to the reference value before the change gradually decreases.

[0047] Incidentally, in the case of an air purifier 1, which has a first air passage 20 and a second air passage 30 that are independent of each other, depending on the operating environment in which the air purifier 1 is installed, a difference in the dust collection state (clogging) between the first filter 21 installed in the first air passage 20 and the second filter 31 installed in the second air passage 30 may occur. If a difference in dust collection state occurs, a difference will also occur in the timing of filter replacement due to a decrease in dust collection capacity, increasing the opportunities for users to perform filter maintenance. Therefore, in order to suppress such a decrease in maintainability, it is necessary to adjust the degree of clogging of the two filters and synchronize the timing of filter replacement.

[0048] In response, the inventor first investigated the relationship between the degree of filter clogging (hereinafter referred to as the decrease in the filter's opening ratio) and the rate of decrease in airflow at the air purifier's outlet. As shown in Figure 5, when the filter's opening ratio decreases to 40%, the airflow at the outlet decreases to 80% or less. Therefore, the inventor defined the period until the filter's opening ratio decreases to 40% as the usable period of the filter and considered adjusting the timing of filter replacement. However, accurately detecting the rate of decrease in airflow at the outlet was not always easy.

[0049] Next, the inventors investigated the relationship between the decrease in the filter's aperture ratio and the rate of increase in pressure loss due to the filter (pressure difference between the upstream and downstream sides of the filter). As shown in Figure 6, when the filter's aperture ratio decreases to 40% (the lower limit of the filter's usable aperture ratio), the pressure loss due to the filter increases to 200%. Furthermore, the lower the filter's aperture ratio, the greater the increase in pressure loss in response to the decrease in aperture ratio. In this case, the pressure difference between the upstream and downstream sides of the filter can be accurately detected by installing a pressure sensor. Therefore, the inventors considered setting the pressure loss due to the unused filter (hereinafter referred to as the initial pressure loss) at 100%, and adjusting the rotation speed of the two fans each time the pressure loss increases by a predetermined amount relative to the initial pressure loss, in order to bring the replacement timing of the two filters closer together.

[0050] As described above, the air purifier 1 of this embodiment includes a first air passage 20 provided with a first filter 21 and a first fan 22, a second air passage 30 independent of the first air passage 20 and provided with a second filter 31 and a second fan 32, a first differential pressure sensor 23 for detecting a first pressure difference P1 of the first filter 21, a second differential pressure sensor 33 for detecting a second pressure difference P2 of the second filter 31, and a control unit 13 for controlling the rotational speed of the first fan 22 and the second fan 32. The control unit 13 controls the rotational speed of at least one of the first fan 22 and the second fan 32 to reduce the difference between the first pressure difference P1 and the second pressure difference P2 when the pressure difference between the first pressure difference P1 of the first filter 21 or the second pressure difference P2 of the second filter 31 becomes greater than or equal to the first reference pressure difference PB1 or the second reference pressure difference PB2. With this configuration, even if the air purifier 1 is installed in an operating environment where there is a difference in the degree of clogging between the first filter 21 and the second filter 31, the fan rotation speed is controlled so that the pressure difference between the two filters decreases each time the pressure difference of one filter reaches a reference pressure difference. This makes it possible to bring the degree of decrease in the dust collection capacity of the first filter 21 and the degree of decrease in the dust collection capacity of the second filter 31 closer together, and to synchronize the replacement timing of both filters.

[0051] Furthermore, in the air purifier 1, the control unit 13 controls the fan rotation speed of the fan whose pressure difference exceeds the reference pressure difference, when either the first pressure difference P1 of the first filter 21 or the second pressure difference P2 of the second filter 31 becomes greater than or equal to the first reference pressure difference PB1 or the second reference pressure difference PB2, by reducing the rotation speed of the fan whose pressure difference exceeds the reference pressure difference and increasing the rotation speed of the fan whose pressure difference does not exceed the reference pressure difference. With this configuration, it is possible to adjust the degree of decrease in the dust collection capacity of the first filter 21 and the second filter 31 while maintaining an airflow that is approximately the same as the airflow of the set operating mode, thereby aligning the replacement timing of both filters.

[0052] Furthermore, in the air purifier 1, the control unit 13 varies the timing of controlling the fan's rotation speed from the timing of controlling the fan's rotation speed to the timing of controlling the fan's rotation speed again, according to the time change in the pressure difference of the filter. In the space where the air purifier 1 is installed, as the level of air cleanliness increases, the rate of increase in the pressure difference of the filter with respect to time decreases. For this reason, it is preferable to vary the timing of controlling the fan's rotation speed according to the time change in the pressure difference.

[0053] Furthermore, in the air purifier 1, the control unit 13 reduces the percentage increase in pressure difference relative to the first reference pressure difference PB1 or the second reference pressure difference PB2 each time it controls the fan rotation speed to reduce the difference between the first pressure difference P1 and the second pressure difference P2, while the first pressure difference P1 of the first filter 21 and the second pressure difference P2 of the second filter 31 continue to increase. The reference pressure difference is changed to a value obtained by adding 10% to the initial pressure difference each time the fan rotation speed is adjusted. Specifically, the first reference pressure difference PB1 or the second reference pressure difference PB2 is changed to 71.5 Pa, 78 Pa, 84.5 Pa, and 91 Pa, respectively, by adding 6.5 Pa, which is 10% of the first initial pressure difference PI1 and the second initial pressure difference PI2 (65 Pa). In other words, the first reference pressure difference PB1 or the second reference pressure difference PB2 has a constant increase of 6.5 Pa, but each time it is changed, the ratio of the increase (6.5 Pa) to the original first reference pressure difference PB1 or second reference pressure difference PB2 (65 Pa, 71.5 Pa, 78 Pa, 84.5 Pa) is controlled to gradually decrease. This makes the difference between the first pressure difference P1 and the second pressure difference P2 when the first pressure difference P1 or second pressure difference P2 reaches the first limit pressure difference PL1 or second limit pressure difference PL2 of 130 Pa (when the filter is replaced) smaller than, for example, the difference when the ratio of the increase in pressure difference to the first reference pressure difference PB1 or second reference pressure difference PB2 is kept constant.

[0054] Furthermore, in the air purifier 1, the increase in pressure difference relative to the first reference pressure difference PB1 or the second reference pressure difference PB2 is calculated based on the first initial pressure difference PI1 and the second initial pressure difference PI2, which are stored in advance. Since the first initial pressure difference PI1 and the second initial pressure difference PI2 are stored for each operating mode (high-speed operation mode, medium-speed operation mode, low-speed operation mode), the fan rotation speed can be appropriately controlled to minimize the difference between the first pressure difference P1 and the second pressure difference P2 based on the increase in pressure difference calculated for each operating mode.

[0055] Furthermore, in the air purifier 1, the control unit 13 issues a notification prompting the replacement of the first filter 21 and the second filter 31 when the pressure difference of at least one filter exceeds the replacement threshold, which is the first limit pressure difference PL1 and the second limit pressure difference PL2. Since the control is set to minimize the difference between the first pressure difference P1 and the second pressure difference P2, maintenance is improved by replacing the first filter 21 and the second filter 31 when the pressure difference of at least one filter exceeds the replacement threshold.

[0056] Furthermore, in the air purifier 1, the first limit pressure difference PL1 and the second limit pressure difference PL2 of the first filter 21 and the second filter 31 are set for each operating mode (high-speed operating mode, medium-speed operating mode, low-speed operating mode), so that the first filter 21 and the second filter 31 can be replaced at the appropriate timing in each operating mode.

[0057] Furthermore, in the air purifier 1, the control unit 13 notifies the system of a malfunction if it determines that the first pressure difference P1 or the second pressure difference P2 has decreased below the first initial pressure difference PI1 and the second initial pressure difference PI2. This allows the system to detect conditions such as when the air purifier is operated without a filter or when the filter is damaged, thereby preventing malfunctions in the air purifier 1.

[0058] Furthermore, in the air purifier 1, if the control unit 13 determines that the first pressure difference P1 or the second pressure difference P2 exceeds the first limit pressure difference PL1 and the second limit pressure difference PL2 at the start of operation of the air purifier 1, it will notify that there is a device malfunction. This allows the system to detect, for example, if the filter packaging is not removed when the air purifier 1 is operated for the first time or when it is operated for the first time after filter replacement, and prevents the air purifier 1 from malfunctioning.

[0059] Furthermore, in the air purifier 1, if the control unit 13 determines that the current detected value of the first pressure difference P1 or the second pressure difference P2 is smaller than the previous detected value, it sets the first reference pressure difference PB1 and the second reference pressure difference PB2 based on the current detected value. This allows for detection of situations such as when the filter is cleaned or replaced before the pressure difference across the filter reaches the first limit pressure difference PL1 and the second limit pressure difference PL2. As a result, the fan rotation speed can be appropriately controlled to minimize the difference between the first pressure difference P1 and the second pressure difference P2, and the replacement timing of both filters can be synchronized.

[0060] Although embodiments of the present invention have been described above, it goes without saying that the technical scope of the present invention should not be interpreted as being limited by the description of these embodiments. These embodiments are merely examples, and it will be understood by those skilled in the art that various modifications to the embodiments are possible within the scope of the invention described in the claims. The technical scope of the present invention should be determined based on the scope of the invention described in the claims and the scope of its equivalents.

[0061] For example, the above embodiment describes a case where there are two air passages (a first air passage 20 and a second air passage 30), but it is not limited to this. The number of air passages may be three or more. Also, the above embodiment describes a case where the structure of the first air passage 20 and the second air passage 30 is symmetrical, but it is not limited to a symmetrical structure. [Explanation of Symbols]

[0062] 1. Air purifier 10 cabinets 11 Front Panel 12 Control section 13 Control Unit 14 intake ports 14A First Inlet 14B Second Inlet 15 Air outlet 15A First outlet 15B Second outlet 20 First air passage 21 First Filter 22 First Fan 23 First differential pressure sensor 30 Second airflow channel 31 Second filter 32 Second Fan 33 Second differential pressure sensor P1 First pressure difference P2 Second pressure difference PB1 First reference pressure difference PB2 Second reference pressure difference PI1 First initial pressure difference PI2 Second initial pressure difference PL1 First Limit Pressure Difference PL2 Second Limit Pressure Difference

Claims

1. An air purifier having at least a first flow path and a second flow path that are independent of each other, The first filter and first fan are provided in the first flow path, The second filter and second fan are provided in the second flow path, A differential pressure sensor detects a first pressure difference, which is the pressure difference between the upstream pressure and the downstream pressure in the first filter, and a second pressure difference, which is the pressure difference between the upstream pressure and the downstream pressure in the second filter. A control unit that controls the first and second fans, It has, The control unit controls the rotation speed of at least one of the first and second fans to reduce the difference between the first and second pressure differences when the pressure difference of either the first or second pressure difference exceeds a reference value. Air purifier.

2. The control unit controls the fan whose pressure difference exceeds the reference value to decrease when either the first or second pressure difference exceeds the reference value, and increases the rotation speed of the fan whose pressure difference does not exceed the reference value. The air purifier according to claim 1.

3. The control unit varies the timing of controlling the rotation speeds of the first and second fans from the timing of controlling the rotation speeds of the first and second fans to the timing of controlling the rotation speeds of the first and second fans, according to the time change of the pressure difference. The air purifier according to claim 1.

4. The control unit, while the pressure difference continues to increase, reduces the ratio of the increase in the pressure difference to the reference value each time it controls the rotation speed of the fan to reduce the difference. The air purifier according to claim 3.

5. The increase in the pressure difference is a value calculated based on the initial value of the pressure difference that is stored in advance. The air purifier according to claim 4.

6. The control unit provides notification to prompt replacement of the first filter and the second filter when the pressure difference of at least one of the first filter and the second filter exceeds a threshold. The air purifier according to claim 4.

7. The aforementioned air purifier is equipped with multiple operating modes with different rotation speeds. The threshold is set for each of the operating modes. The air purifier according to claim 6.

8. The control unit shall notify that the device is malfunctioning if it determines that the first pressure difference or the second pressure difference has decreased below the initial value. The air purifier according to claim 1.

9. The control unit shall notify the system of a malfunction if it determines that the first pressure difference or the second pressure difference exceeds a threshold when the air purifier starts operating or immediately after the first and second fans are replaced. The air purifier according to claim 1.

10. If the control unit determines that the current detected value in the first pressure difference or the second pressure difference is smaller than the previous detected value, it sets a reference value for the pressure difference based on the current detected value. The air purifier according to claim 1.

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