Ventilation device, heat-exchanging ventilation device, nad blowing device

Abstract

To accurately determine a clogging of a filter even under an impact of external wind for a long period of time such as when a typhoon approaches.SOLUTION: A ventilation device includes: filters 3, 4 provided in a first air path which is at least one air path of air inlet paths 5, 6 and air outlet paths 7, 8 for removing contaminants from air sucked into the first air path; and a control part 14 for acquiring a first current of motors 9a, 10a when the motors 9a, 10a of first blowers 9, 10 provided on the first air path are rotated at a first rotation speed, and a second current of the motors 9a, 10a when the motors 9a, 10a of the first blowers 9, 10 are rotated at a second rotation speed which is larger than the first rotation speed, calculates a ratio of differences between the second current and the first current with respect to a difference between the second rotation speed and the first rotation speed, and determines that the filters 3, 4 are clogged when the ratio is a reference value or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a ventilation device, a heat exchange type ventilation device, and an air blower. [Background technology]

[0002] Living spaces where people live, such as homes and offices, are subject to pollutants that contaminate the indoor air environment, such as carbon dioxide emitted from human breath, viruses emitted from human breath, volatile organic compounds (VOCs) emitted from building materials, odors from toilets, kitchens, and animals. As a countermeasure against these pollutants, homes and offices are equipped with ventilation systems. Ventilation systems purify the indoor environment by replacing polluted indoor air with outdoor air.

[0003] Conventional ventilation systems are equipped with filters that remove pollutants from the air flowing through the air duct. When the ventilation system is operated for a long time, foreign matter adheres to the filter, causing it to become clogged. When the filter becomes clogged, the ventilation volume of the ventilation system decreases, making it impossible to ventilate sufficiently. Furthermore, in the case of heat exchange type ventilation systems that have a heat exchanger, the heat exchange efficiency of the ventilation system decreases, making it impossible to exchange heat sufficiently inside and outside the ventilation system. Therefore, in order to maintain the performance of the ventilation system, it is necessary to properly clean or replace the filter before it becomes clogged.

[0004] Patent Document 1 discloses a heat exchange ventilator that stores, as initial values, the current and / or rotation speed of an air supply motor adjusted to maintain a constant air supply volume, and then stores a value obtained by averaging the stored multiple currents and / or rotation speeds. If the difference between the current current and / or rotation speed and the current and / or rotation speed stored as the initial value exceeds a predetermined value, the heat exchange ventilator issues a warning that the air supply filter is clogged. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-90593 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the ventilation device disclosed in Patent Document 1 has a problem in that it is not possible to accurately determine whether the filter is clogged when the device is subject to the influence of outside winds for a long period of time, such as when a typhoon is approaching.

[0007] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a ventilation device that can accurately determine whether a filter is clogged, even when it is affected by outside winds for a long period of time, such as when a typhoon is approaching. [Means for solving the problem]

[0008] The ventilation device of the present disclosure includes an intake air duct for supplying outdoor air into a room, an intake air blower provided in the intake air duct, an exhaust air duct for exhausting indoor air to the outside, an exhaust air blower provided in the exhaust air duct, a filter provided in a first air duct which is at least one of the intake air duct and the exhaust air duct and which removes contaminants from air drawn into the first air duct, and a control unit that acquires a first current of a motor of a first blower provided in the first air duct when the motor is rotated at a first rotation speed and a second current of the motor when the motor of the first blower is rotated at a second rotation speed greater than the first rotation speed, calculates the ratio of the difference between the second current and the first current to the difference between the second rotation speed and the first rotation speed, and determines that the filter is clogged if this ratio is equal to or less than a reference value. [Effects of the Invention]

[0009] According to the ventilation device of the present disclosure, it is possible to accurately determine whether the filter is clogged, even when the device is exposed to outside wind for a long period of time, such as when a typhoon is approaching. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating the configuration of a ventilation device according to a first embodiment. [Figure 2] 5 is a flowchart illustrating a method for performing initial setting to determine whether a filter of the ventilation device of the first embodiment is clogged. [Figure 3] 4 is a graph showing the relationship between the rotation speed and current of the air supply motor in the ventilation device of the first embodiment. [Figure 4] 10 is a graph showing the relationship between air volume Q and static pressure P, and the relationship between air volume Q and current I, when the air supply motor is controlled to have a constant rotation speed in the ventilation device of the first embodiment. [Figure 5] 4 is a graph showing the relationship between the rotation speed and current of the air supply motor in the ventilation device of the first embodiment. [Figure 6] FIG. 4 is a diagram showing the relationship between the air volume and the slope (dI / dN) in the ventilation device of the first embodiment. [Figure 7] 4 is a flowchart illustrating a method for determining whether a filter of the ventilation device is clogged in the first embodiment. [Figure 8] 4 is a graph showing an example of a change over time in current of an air intake motor or an exhaust motor in the ventilation device of the first embodiment. [Figure 9] 1 is a graph illustrating the influence of outside wind in the ventilation device of the first embodiment, showing the relationship between the rotation speed of the air intake motor or the exhaust motor and the current. [Figure 10] 10 is a graph showing the relationship between the cumulative operation time since the start of use of the filter and the slope (dI / dN), for illustrating a method for determining whether the filter of the ventilation device of the second embodiment is clogged. DETAILED DESCRIPTION OF THE INVENTION

[0011] Embodiments for implementing the subject matter of the present disclosure will be described with reference to the accompanying drawings. In each drawing, the same or corresponding parts are designated by the same reference numerals, and redundant explanations are appropriately simplified or omitted. In each drawing, the scale of each component may differ from the actual scale for ease of understanding. Note that the subject matter of the present disclosure is not limited to the following embodiments, and any component of the embodiments may be modified or omitted within the scope of the gist of the present disclosure.

[0012] Embodiment 1 Fig. 1 is a diagram illustrating the configuration of a ventilation device according to embodiment 1. Ventilation device 1 according to embodiment 1 includes an intake air blower 9, an exhaust air blower 10, a heat exchanger 2, an intake air filter 3, an exhaust air filter 4, a control unit 14, an outdoor air temperature sensor 11, and an indoor temperature sensor 12. Ventilation device 1 according to embodiment 1 is a heat exchange type ventilation device having heat exchanger 2 therein.

[0013] The ventilation device 1 has an outdoor air inlet 15 and an outdoor air outlet 18 on one side surface, and an indoor air outlet 16 and an indoor air inlet 17 on the side surface opposite to this side surface. The ventilation device 1 has an intake air duct 5 on the outdoor side of the heat exchanger 2, an intake air duct 6 on the indoor side of the heat exchanger 2, an exhaust air duct 7 on the indoor side of the heat exchanger 2, and an exhaust air duct 8 on the outdoor side of the heat exchanger 2. The outdoor air supply duct 5 and the indoor air supply duct 6 are air supply ducts that connect the outdoor air intake 15 and the indoor air outlet 16, and the indoor air exhaust duct 7 and the outdoor air exhaust duct 8 are exhaust ducts that connect the indoor air intake duct 17 and the indoor air outlet 16. Inside the ventilation device 1, supply air passages 5 and 6 and exhaust air passages 7 and 8, which are partitioned from each other, are formed so as to pass through the heat exchanger 2.

[0014] The ventilation device 1 is installed, for example, in the ceiling of a building, and exchanges indoor air with outdoor air. That is, the ventilation device 1 supplies outdoor air OA (Outdoor Air) into the room as supply air SA (Supply Air), and discharges indoor air RA (Return Air) to the outside as exhaust air EA (Exhaust Air). Heat is exchanged between the outdoor air and the indoor air by a heat exchanger 2.

[0015] The air intake blower 9 has an air intake motor 9a therein for driving the air intake blower 9. The exhaust blower 10 has an exhaust motor 10a therein for driving the exhaust blower 10. The air intake blower 9 detects the rotation speed and current of the air intake motor 9a and outputs them to the control unit 14. The exhaust blower 10 detects the rotation speed and current of the exhaust motor 10a and outputs them to the control unit 14.

[0016] The control unit 14 includes an electric circuit for controlling the various devices that make up the ventilation device 1, a microcomputer, a memory unit 14a, and the like. The control unit 14 uses the rotation speed or current of the air supply motor 9a and the rotation speed or current of the exhaust motor 10a input from the air supply blower 9 and the exhaust blower 10, respectively, to adjust the output to the air supply motor 9a and the exhaust motor 10a so that they operate at the target rotation speed or target current for each pre-set air volume notch.

[0017] The intake air filter 3 is provided in the intake air duct 5 on the outdoor side, and captures contaminants such as dust contained in the intake air flow generated by the intake air blower 9. The exhaust filter 4 is provided in the exhaust air duct 7 on the indoor side, and captures pollutants such as dust contained in the exhaust airflow generated by the exhaust fan 10. The intake air filter 3 and the exhaust air filter 4 are disposed in the immediate vicinity of and upstream of the heat exchanger 2, respectively. In the following description, when there is no need to distinguish between the intake air filter 3 and the exhaust air filter 4, they may be simply referred to as "filters."

[0018] An outdoor air temperature sensor 11 is provided in the supply air duct 5 on the outdoor side of the ventilation device 1. The outdoor air temperature sensor 11 measures the temperature of the outdoor air (i.e., air supplied from the outdoors to the indoors) drawn into the ventilation device 1. The temperature measured by the outdoor air temperature sensor 11 is stored in the memory unit 14a of the control unit 14. Similarly, an indoor temperature sensor 12 is provided in the indoor exhaust air duct 7. The indoor temperature sensor 12 measures the temperature of the indoor air drawn into the ventilation device 1 (i.e., the air exhausted from the room to the outside). The temperature measured by the indoor temperature sensor 12 is stored in the memory unit 14a of the control unit 14.

[0019] The control unit 14 communicates with a terminal communication unit 70 of the information terminal 60, which will be described later. The communication method between the control unit 14 and the terminal communication unit 70 may be wireless communication using Wi-Fi (registered trademark) (Wireless Fidelity) or Bluetooth (registered trademark), or may be wired communication.

[0020] The memory unit 14a is a memory unit that stores information necessary for controlling the ventilation device 1. The memory unit 14a stores information such as various control setting values ​​and programs for controlling the operation of the ventilation device 1. The memory unit 14a stores information such as the power-on time of the ventilation device 1, the operation time of the ventilation device 1, the stop time of the ventilation device 1, and the setting pattern of the ventilation air volume of the ventilation device 1 (for example, patterns such as strong operation, weak operation, and constant air volume operation). The memory unit 14a is a non-volatile memory unit, and is configured with a semiconductor storage medium such as a flash memory. In FIG. 1, the storage unit 14a is provided inside the control unit 14 as an integral part of the control unit 14, but it may be provided outside the control unit 14 as a separate unit.

[0021] The control unit 14 is a control unit that controls the overall operation of the ventilation device 1. The control unit 14 is placed in a position accessible from an inspection hatch of the ventilation device 1 so that maintenance can be easily performed outside the housing (not shown) that encloses the main body of the ventilation device 1. The control unit 14 controls the operation of the intake air blower 9 and the exhaust air blower 10 to control the operation of the ventilation device 1. The control unit 14 controls the air volume of the intake air blower 9 and the exhaust air blower 10 to control the ventilation air volume. The control unit 14 can send and receive information via the terminal communication unit 70 of the information terminal 60.

[0022] An outdoor air supply duct 20 is connected to the ventilation device 1, and connects an outdoor air intake 31 provided on the exterior wall of the building 600 to the outdoor air inlet 15 of the ventilation device 1. In addition, air intakes (not shown) to each room are provided inside the building 600, and an indoor air supply duct 21 is connected to the ventilation device 1, connecting the air intakes to the indoor air outlet 16 of the ventilation device 1. The flow path that connects the outside of the building 600 (i.e., the outdoors) with the inside of the building 600, passing through the outdoor air supply duct 20, the supply air ducts 5 and 6 of the ventilation device 1, and the indoor air supply duct 21 to the air intakes to each room, corresponds to the air supply flow path.

[0023] An indoor exhaust duct 22 is connected to the ventilation device 1, and connects a return air vent (not shown) provided in a room of the building 600 to an indoor air inlet 17 of the ventilation device 1. An outdoor exhaust duct 23 is also connected to the ventilation device 1, and connects an outdoor air outlet 18 to an exhaust vent 32 provided on the outer wall of the building 600. The flow path that connects the indoor and outdoor areas of the building 600, from the return air vent through the indoor exhaust duct 22, exhaust air passages 7 and 8 of the ventilation device 1, and the outdoor exhaust duct 23 to the exhaust vent 32, corresponds to the exhaust flow path.

[0024] The information terminal 60 is an operating device that can operate the operation of the ventilation device 1, that is, an operating device that allows the administrator of the ventilation device 1 to select the operation of the ventilation device 1. The information terminal 60 can operate instructions to control the operation of the ventilation device 1. The information terminal 60 operates, stops, and switches the ventilation volume of the ventilation device 1. In addition, the administrator of the ventilation device 1 operates the information terminal 60 to change settings for information related to the maintenance of the intake air filter 3 and exhaust filter 4. The results of operating the information terminal 60 are displayed, for example, on the display unit of the information terminal 60.

[0025] The control unit 14 processes the operation information acquired from the information terminal 60 and the operation information of the ventilation device 1 stored in the memory unit 14a, and controls the air supply motor 9a and the exhaust motor 10a in accordance with the processed information.

[0026] In the above explanation, the control unit 14 obtains information regarding the operation of the ventilation device 1 and maintenance information for the intake air filter 3 and exhaust filter 4 from the information terminal 60, but this information may also be obtained from a cloud server via the Internet using an app dedicated to the ventilation device 1.

[0027] A method for determining whether the filter of the ventilation device 1 is clogged will be described with reference to FIG. FIG. 2 is a flowchart illustrating a method for performing initial setting for determining whether the filter of the ventilation device according to the first embodiment is clogged. In step S11, the control unit 14 determines whether or not the ventilation device 1 can transition to the test operation mode. The control unit 14 determines that the ventilation device 1 can transition to the test operation mode when the following conditions (1) to (3) are met. (1) The surrounding environment at the installation location of the ventilation device 1 is free of problems (for example, there is no strong wind blowing in due to the influence of a typhoon, etc.). (2) Each ventilation duct (specifically, the outdoor air supply duct 20, the indoor air supply duct 21, the indoor exhaust duct 22, and the outdoor exhaust duct 23) is connected to the ventilation device 1. (3) The intake air filter 3 and exhaust air filter 4 are installed correctly. If the installer or manager of the ventilation device 1 determines that there are no problems with the above conditions (1) to (3) by visually checking or the like, the installer or manager inputs the information into the information terminal 60. The control unit 14 acquires the information input into the information terminal 60 by the installer or manager from the information terminal 60, and determines whether the ventilation device 1 can transition to the trial operation mode.

[0028] If the control unit 14 determines that the ventilation device 1 can transition to trial operation mode (i.e., if the answer is Yes in step S11), the processing proceeds to step S13, and if the control unit 14 does not determine that the ventilation device 1 can transition to trial operation mode (i.e., if the answer is No in step S11), the processing proceeds to step S12.

[0029] In step S12, the control unit 14 prompts the installer or manager of the ventilation device 1 to confirm and input the above conditions (1) to (3) via the information terminal 60, and repeats the process of step S11.

[0030] In step S13, the control unit 14 notifies the information terminal 60 that a test run can be started, and upon receiving a test run start command from the information terminal 60, causes the air intake motor 9a and the exhaust motor 10a to start operating at a preset rotation speed N1, and proceeds to step S14. The control unit 14 starts acquiring measurement information on the current and rotation speed of the air intake motor 9a and the exhaust motor 10a.

[0031] In step S14, the control unit 14 determines whether the measurement information of the current and rotation speed of the air intake motor 9a and the exhaust motor 10a is stable. If the control unit 14 determines that the measurement information of the current and rotation speed of the air intake motor 9a and the exhaust motor 10a is stable (i.e., if Yes in step S14), the process proceeds to step S15, and if the control unit 14 does not determine that the measurement information is stable (i.e., if No in step S14), the process of step S14 is repeated until the measurement information is stable.

[0032] In step S15, the control unit 14 stores in the memory unit 14a the measurement information of the current and rotation speed of the air supply motor 9a and the exhaust motor 10a when the air supply motor 9a and the exhaust motor 10a are operated at a predetermined rotation speed N1, and then proceeds to step S16.

[0033] In step S16, the control unit 14 starts operating the air intake motor 9a and the exhaust motor 10a at a preset rotation speed N2, and the process proceeds to step S17. The rotation speed N2 is set to be higher than the rotation speed N1. The control unit 14 starts acquiring measurement information on the current and rotation speed of the air intake motor 9a and the exhaust motor 10a.

[0034] In step S17, the control unit 14 determines whether the measurement information of the current and rotation speed of the air intake motor 9a and the exhaust motor 10a is stable, as in step S14. If the control unit 14 determines that the measurement information of the current and rotation speed of the air intake motor 9a and the exhaust motor 10a is stable (i.e., if Yes in step S17), the process proceeds to step S18, and if the control unit 14 does not determine that the measurement information is stable (i.e., if No in step S17), the process of step S17 is repeated until the measurement information is stable.

[0035] In step S18, the control unit 14 stores in the memory unit 14a the measurement information of the current and rotation speed of the air supply motor 9a and the exhaust motor 10a when the air supply motor 9a and the exhaust motor 10a are operated at a predetermined rotation speed N2, and then proceeds to step S19.

[0036] In step S19, the control unit 14 determines whether the number of repetitions of the series of processes from step S13 to step S18 has reached a preset number n. If the control unit 14 determines that the number of repetitions has reached n (i.e., if Yes in step S19), the process proceeds to step S20, and if the control unit 14 does not determine that the number of repetitions has reached n (i.e., if No in step S19), the process from step S13 to step S18 is repeated until the number of repetitions reaches n.

[0037] In step S20, the control unit 14 calculates the average values ​​of the current and rotation speed measured when the motor is operated at rotation speed N1 and the average values ​​of the current and rotation speed measured when the motor is operated at rotation speed N2, which are stored in the n-time repetitions of the series of processes from step S13 to step S18, and proceeds to step S21.

[0038] In step S21, the control unit 14 calculates the ratio of change in current I to change in rotation speed N using the average values ​​of current and rotation speed when operated at rotation speed N1 and the average values ​​of current and rotation speed when operated at rotation speed N2. In the following description, the rate of change in current relative to change in rotation speed may be referred to as "slope (dI / dN)." Also, in the following description, the current when rotated at rotation speed N1 may be referred to as "first current," and the current when rotated at rotation speed N2 may be referred to as "second current."

[0039] The processing in steps S21 and S22 in FIG. 2 will be described with reference to FIG. In the following explanation of Figures 3 to 6, we will explain a method of controlling the air intake motor 9a to determine whether the air intake filter 3 is clogged, but the exhaust motor 10a can also be controlled in a similar manner to determine whether the exhaust filter 4 is clogged.

[0040] Figure 3 is a graph showing the relationship between the rotation speed and current of the air intake motor in the ventilation device of embodiment 1, and is a graph showing the relationship between the average value of the current of the air intake motor when the air intake motor is rotated at rotation speed N1 and the average value of the current of the air intake motor when the air intake motor is rotated at rotation speed N2. 3, the rate of change in the current of the air intake motor 9a relative to the rotation speed of the air intake motor 9a when the air intake filter 3 is new is indicated as "initial value (dI0 / dN0)." In step S21, the control unit 14 calculates the initial value of the slope (dI0 / dN0). In addition, the air intake filter 3 is in a new state when a newly installed ventilation device 1 has just been put into use, or when the air intake filter 3 has been replaced or cleaned and the ventilation device 1 has just been put into use.

[0041] In addition, in FIG. 3, the ratio of the change in current of air supply motor 9a to the change in the rotation speed of air supply motor 9a when it is determined that the air supply filter is clogged is shown as "determination threshold value (dI2 / dN2)." In step S22, the control unit 14 calculates the slope determination threshold value (dI2 / dN2) from the initial slope value (dI0 / dN0) calculated in step S21, stores it in the storage unit 14a, and ends the initial setting.

[0042] Even if the rotation speed of the air intake motor 9a is constant, clogging will reduce the airflow and current. The minimum airflow limit at which the ventilation device 1 can be used without problems (e.g., a 20% reduction from the initial airflow) is pre-stored in the memory unit 14a. The slope determination threshold (dI2 / dN2) is calculated from the average current corresponding to the rotation speed N1 of the air intake motor 9a when the air intake filter 3 is new, the average current corresponding to the rotation speed N2 of the air intake motor 9a, and the current reduction rates corresponding to the rotation speeds N1 and N2 when the airflow is at the minimum limit. The slope determination threshold (dI2 / dN2) is the reference value for determining whether the air intake filter 3 is clogged.

[0043] In other words, the control unit 14 calculates the ratio as an initial value when the use of the intake air filter 3 begins, and calculates the reference value based on the calculated initial value and the rate of change of the first current and the second current when the air volume in the intake air ducts 5, 6 decreases from the air volume when the use of the intake air filter 3 begins to the air volume at which the intake air filter 3 is determined to be clogged.

[0044] It should be noted that the current change rate used to calculate the slope judgment threshold is not constant, and a map may be stored in the control unit 14 so that it changes depending on the initial value (for example, characteristic values ​​such as current and air volume when the filter is new).

[0045] Next, a method for determining whether a filter is clogged will be described. FIG. 4 is a graph showing the relationship between airflow Q and static pressure P, and the relationship between airflow Q and current I, when the air intake motor is controlled to a constant rotation speed in the ventilation device of embodiment 1. FIG. 4 also shows P-Q curves for rotation speeds N1 and N2, as well as a pressure loss curve for a brand new air intake filter and a pressure loss curve for a clogged air intake filter. As shown in FIG. 4, when the air intake filter 3 is brand new, the airflow is Q1 at rotation speed N1. As the rotation speed is increased from N1 to N2, the airflow increases to Q2. When the ventilation device 1 is operated for a long period of time, dust and other particles accumulate on the air intake filter 3, gradually increasing the pressure loss, and both the airflow Q1 at rotation speed N1 and the airflow Q2 at rotation speed N2 decrease.

[0046] 4 also shows the current when air intake filter 3 is new and when it is clogged, for each of rotation speeds N1 and N2. Memory unit 14a of control unit 14 has stored in advance data on changes in current when air intake filter 3 is new and when it is clogged, for each of rotation speeds N1 and N2. Control unit 14 derives the current (current decrease rate) when air intake filter 3 is clogged from this current change data and the current at air volumes Q1 and Q2 when air intake filter 3 is new, and calculates the slope determination threshold (dI2 / dN2).

[0047] FIG. 5 is a diagram showing the relationship between the rotation speed and current of the air intake motor of the ventilation device of the first embodiment. As shown in FIG. 5, when the air intake filter 3 is new, the current is I2 at rotation speed N1 and is I1 at rotation speed N2. When the air intake filter 3 is clogged, the current decreases from I2 to I21 at rotation speed N1, and decreases from I1 to I11 at rotation speed N2. The rate of decrease in current when the air intake filter 3 is clogged is greater at rotation speed N2, which is higher, than at rotation speed N1, which is lower. Therefore, the rate of change in current with respect to change in rotation speed (i.e., the "slope (dI / dN)") is large when the air intake filter 3 is new and decreases when the air intake filter 3 is clogged.

[0048] FIG. 6 is a diagram showing the relationship between air volume and slope (dI / dN) in the ventilation device of embodiment 1. When the air intake filter 3 is new, the slope (dI / dN) is large and the air volume is also large. The air volume when the air intake filter 3 is new is the initial value. As the air intake filter 3 becomes more clogged, the pressure loss increases and the slope (dI / dN) decreases. When the air intake filter 3 is clogged, the slope (dI / dN) is small and the air volume is also small. The slope (dI / dN) at the lowest air volume at which the ventilation device 1 can be used without problems is set as the judgment threshold value.

[0049] FIG. 7 is a flowchart illustrating a method for determining whether a filter of the ventilation device is clogged according to the first embodiment. In step S30, the control unit 14 determines whether or not the initial settings for determining clogging of the intake air filter 3 and the exhaust air filter 4 have been completed, as described with reference to Fig. 2. If the control unit 14 determines that the initial settings have been completed (i.e., if Yes in step S30), the process proceeds to step S13, and if the control unit 14 does not determine that the initial settings have been completed (i.e., if No in step S30), the process proceeds to step S31. In step S31, the control unit 14 performs initial settings for determining whether the intake air filter 3 and the exhaust air filter 4 are clogged, and then returns the process to step S30.

[0050] The processing from step S13 to step S20 in FIG. 7 is the same as the processing from step S13 to step S20 in FIG. 2, and therefore a description thereof will be omitted.

[0051] When the process of step S20 ends, the control unit 14 advances the process to step S40. In step S40, the control unit 14 calculates the ratio of change in current I to change in rotation speed N (i.e., the slope (dI / dN)) using the average value of the measurement information of current and rotation speed when operating at rotation speed N1 and the average value of the measurement information of current and rotation speed when operating at rotation speed N2, and proceeds to step S41.

[0052] In step S41, control unit 14 determines whether the slope (dI / dN) calculated in step S40 is equal to or less than the judgment threshold calculated in the initial setting. If the slope (dI / dN) is equal to or less than the judgment threshold, control unit 14 determines that intake air filter 3 or exhaust filter 4 is clogged. If the slope (dI / dN) is greater than the judgment threshold, control unit 14 determines that intake air filter 3 and exhaust filter 4 are not clogged. If control unit 14 determines that the slope calculated in step S40 is equal to or less than the judgment threshold (i.e., if Yes in step S41), control unit 14 proceeds to step S42. If control unit 14 does not determine that the slope calculated in step S40 is equal to or less than the judgment threshold (i.e., if No in step S41), control unit 14 returns to step S13.

[0053] In step S41, control unit 14 notifies the manager of ventilation device 1 that intake air filter 3 or exhaust filter 4 is clogged, and the process returns to step S13. This notification is made, for example, by control unit 14 sending information that the filter is clogged to information terminal 60, and information terminal 60 displaying or emitting a sound that intake air filter 3 or exhaust filter 4 is clogged. This notification lets the manager of ventilation device 1 know that intake air filter 3 or exhaust filter 4 is clogged, and they can clean or replace intake air filter 3 or exhaust filter 4.

[0054] Here, the effect of wind outside the ventilation device 1 (i.e., outside wind) on filter clog detection will be described. FIG. 8 is a graph showing an example of the change over time in the current of the intake air motor or the exhaust air motor. In FIG. 8, the horizontal axis represents the current observation time, and the vertical axis represents the current of the intake air motor 9a or the exhaust air motor 10a. In FIG. 8, the current is almost constant from midnight on the left side of the graph to around 6:00, then decreases from around 6:00 to around 14:00 the following day, and from around 14:00 the following day, the current returns to its pre-decline state and becomes almost constant. The reason why the current fluctuates greatly and decreases from around 6:00 to around 14:00 the following day is because outside wind is blowing in from outside the ventilation device 1, causing the current to be affected by the outside wind.

[0055] In conventional ventilation systems, when the influence of outside wind is short-term, it is sometimes possible to eliminate the influence of outside wind by averaging the acquired current. The "average current" in Figure 8 is the average current value when the influence of outside wind is short-term, but when the influence of outside wind continues for a long period of time, as in Figure 8, the average current value decreases due to the influence of outside wind. For this reason, when the influence of outside wind continues for a long period of time, as in Figure 8, the influence of outside wind cannot be eliminated even by averaging the current, and the current will include the influence of outside wind, resulting in a problem where the system mistakenly determines that the filter is clogged and issues an alarm even when it is not actually clogged.

[0056] In contrast to this, the ventilation device 1 of the first embodiment can suppress the influence of outside wind and accurately determine whether the intake air filter 3 and the exhaust air filter 4 are clogged. The reason for this will be explained using FIG. FIG. 9 is a graph illustrating the relationship between the rotation speed and current of the intake motor or exhaust motor in the ventilation device of the first embodiment, illustrating the effect of outside wind. Even when the current decreases due to the effect of outside wind, as shown in FIG. 9, the amount of decrease in current is the same when the rotation speed is N2, which is high, and when the rotation speed is N1, which is low. Therefore, the slope (dI / dN) does not change regardless of whether or not there is an effect of outside wind. As such, since the slope (dI / dN) is not easily affected by outside wind, by using the slope (dI / dN) to determine filter clogging, it is possible to suppress false detection of filter clogging and accurately determine clogging even when there is an effect of outside wind for a long period of time, such as during a typhoon.

[0057] Although the first embodiment has been described as an example in which both the intake air filter 3 and the exhaust air filter 4 are provided, it is also possible to provide only one of the intake air filter 3 and the exhaust air filter 4. For example, only the intake air filter 3 may be provided to prevent pollutants from flowing into the room from the outside.

[0058] Although the first embodiment describes a method for simultaneously determining whether both the intake air filter 3 and the exhaust filter 4 are clogged, the intake air filter 3 and the exhaust filter 4 may be determined to be clogged at different times. Also, the clogging of only one of the intake air filter 3 and the exhaust filter 4 may be determined.

[0059] In the first embodiment, an example has been described in which the slope at the start of filter use is calculated as an initial value, and this initial value is used to calculate a reference value for determining whether the filter is clogged. Calculating the reference value using the initial value makes it less susceptible to the influence of individual differences in the ventilation device 1 or the installation environment, allowing for accurate determination of whether the filter is clogged. However, whether the filter is clogged may also be determined by comparing with a preset reference value.

[0060] In the first embodiment, the ventilator 1 measures the current at two rotation speeds and calculates the slope (dI / dN), but it may also measure the current at three or more rotation speeds and calculate the slope (dI / dN). That is, it may measure the current at multiple rotation speeds and calculate the slope (dI / dN).

[0061] In the first embodiment, an example of a heat exchange type ventilation device having a heat exchanger 2 has been described, but a ventilation device without a heat exchanger 2 may also be used.

[0062] As described above, the ventilation device 1 of the first embodiment includes the intake air ducts 5, 6 for supplying outdoor air into the room, the intake air blower 9 provided in the intake air ducts 5, 6, the exhaust air ducts 7, 8 for exhausting indoor air to the outside, the exhaust air blower 10 provided in the exhaust air ducts 7, 8, a filter (intake air filter 3 or exhaust filter 4) provided in a first air duct (the intake air ducts 5, 6 or the exhaust air ducts 7, 8) which is at least one of the intake air ducts 5, 6 and the exhaust air ducts 7, 8 and which removes pollutants from the air drawn into the first air duct, and The ventilation device 1 further includes a control unit 14 that acquires a first current of a motor (air supply motor 9a or exhaust motor 10a) of a first fan (air supply fan 9 or exhaust fan 10) installed in the first air passage when the motor is rotated at a first rotation speed and a second current of the motor when the motor of the first fan is rotated at a second rotation speed greater than the first rotation speed, calculates the ratio of the difference between the second current and the first current to the difference between the second rotation speed and the first rotation speed, and determines that the filter is clogged if this ratio is equal to or less than a reference value. The ventilation device 1 configured in this manner can accurately determine whether the filter is clogged even when it is subject to external winds for a long period of time, such as when a typhoon is approaching.

[0063] The ventilation device 1 of the first embodiment may measure the current multiple times over two or more days and calculate the slope (dI / dN) using the average value. Filter clogging is caused by the accumulation of dust on the filter and does not occur suddenly in a short period of time. In this way, the current is measured multiple times over a period of time, and the slope (dI / dN) is calculated using the average value. If the slope (dI / dN) is determined to be equal to or less than the determination threshold, the filter is determined to be clogged. This method makes the ventilation device 1 even less susceptible to the effects of outside wind, thereby further improving the accuracy of determining whether the filter is clogged.

[0064] The ventilation device 1 of the first embodiment may be configured to calculate the above-mentioned slope (dI / dN) at a time when a user is absent from the environment in which the ventilation device 1 is installed, and determine whether the intake air filter or the exhaust air filter 4 is clogged. The time when a user is absent is, for example, late at night. The ventilation device 1 may be configured so that the time when a user is absent can be set by an administrator of the ventilation device 1.

[0065] To determine whether the intake air filter 3 and the exhaust air filter 4 are clogged, the intake air motor 9a and the exhaust air motor 10a are operated at two rotation speeds, but these operating modes are different from the preset normal operating mode. Therefore, when a user is in the environment where the ventilation device 1 is installed, the switching sound caused by the change in rotation speed, especially when changing the rotation speed, may lead the user to mistakenly believe that there is an abnormality in the ventilation device 1. In response to this, by setting the control to calculate the slope (dI / dN) to occur when the user is absent, it is possible to prevent the user from mistaking the situation.

[0066] As shown in FIG. 1, when the ventilation device 1 is a heat exchange type ventilation device having a heat exchanger 2, it is possible to prevent the heat exchange efficiency of the ventilation device 1 from decreasing, preventing sufficient heat exchange between the inside and outside of the ventilation device 1.

[0067] In the first embodiment, the ventilation device 1 has been described as having the supply air passages 5, 6 and the exhaust air passages 7, 8, but the ventilation device may not be provided with the exhaust air passages 7, 8. This air blower includes air intake ducts 5 and 6 for supplying outdoor air into the room, an air intake fan 9 having an air intake motor 9a and provided in the air intake ducts 5 and 6, an air intake filter 3 provided in the air intake ducts 5 and 6 for removing contaminants from the air drawn into the air intake ducts 5 and 6, and a control unit 14 that rotates the air intake motor 9a at a first rotation speed, acquires a first current through the air intake motor 9a when the motor is rotated at the first rotation speed, and a second current through the air intake motor 9a when the motor is rotated at a second rotation speed greater than the first rotation speed, calculates the ratio of the difference between the second current and the first current to the difference between the second rotation speed and the first rotation speed, and determines that the air intake filter 3 is clogged if this ratio is equal to or less than a reference value. This air blower can accurately determine whether the air intake filter 3 is clogged, even when exposed to external winds for a long period of time, such as when a typhoon is approaching.

[0068] Embodiment 2 A ventilation device of a second embodiment will be described with reference to Fig. 10. The ventilation device 1 of the second embodiment differs from the ventilation device 1 of the first embodiment in that it estimates when the filter of the ventilation device 1 will become clogged. In the following explanation, only the differences from the ventilation device 1 of the first embodiment will be described.

[0069] FIG. 10 is a graph illustrating the relationship between the cumulative operating time since the start of filter use and the slope (dI / dN) for explaining a method for determining clogging of the filter of the ventilation device of the second embodiment. In FIG. 10, the horizontal axis represents the cumulative operating time of the ventilation device 1 since the filter was new, and the vertical axis represents the slope (dI / dN) calculated using the method described in the first embodiment. As shown in FIG. 10, the slope (dI / dN) gradually decreases as the cumulative operating time of the ventilation device 1 since the filter was new increases. This is because dust adhesion to the filter increases pressure loss through the filter, resulting in a decrease in current. In FIG. 10, the slope (dI / dN) calculated by measuring the current multiple times over a period of approximately 34 months from the filter's new state is shown as a solid line, and the dashed line represents an extrapolated line from that line. The period indicated by the solid line can be considered to be an actual measurement period, and the period indicated by the dashed line can be considered to be an estimated period without actual measurements. The dashed line reaches the threshold slope (dI / dN) approximately 70 months after the filter is new. In this way, the ventilation device 1 can estimate that the filter will become clogged approximately 36 months from the current time. The ventilation device 1 displays the number of days until the filter becomes clogged on the information terminal 60 as the number of days remaining until maintenance such as filter cleaning or filter replacement is performed, allowing the administrator of the ventilation device 1 to know when maintenance is due. In addition, the control unit 14 may not only display the number of days remaining until the filter is cleaned or replaced on the information terminal 60, but may also send the information on the number of days remaining to a cloud server via the Internet using an app dedicated to the ventilation device 1, and notify the administrator of the ventilation device 1 of the information on the number of days remaining via the cloud server.

[0070] As described above, according to the ventilation device 1 of the second embodiment, the time when the filter will become clogged is predicted and reported before the filter becomes clogged, so that the manager of the ventilation device 1 can grasp the clogged state of the filter in the actual environment in which the ventilation device 1 is used. This allows the manager of the ventilation device 1 to consider a maintenance plan, from arranging parts such as filters to performing maintenance, before the operation of the ventilation device 1 is stopped. This makes it possible to solve the problem of the room or building in which the ventilation device 1 is installed being unable to be used for a long period of time due to concerns about insufficient ventilation in the environment in which the ventilation device 1 is used, from the time the ventilation device 1 is stopped until maintenance is completed. [Explanation of symbols]

[0071] 1 ventilation device, 2 heat exchanger, 3 intake air filter, 4 exhaust filter, 5 outdoor intake air duct, 6 indoor intake air duct, 7 indoor exhaust air duct, 8 outdoor exhaust air duct, 9 intake air blower, 9a intake air motor, 10 exhaust air blower, 10a exhaust motor, 11 outdoor air temperature sensor, 12 indoor temperature sensor, 14 control unit, 14a memory unit, 15 outdoor air intake port, 16 indoor air outlet, 17 indoor air intake port, 18 outdoor air outlet, 20 outdoor intake air duct, 21 indoor intake air duct, 22 indoor exhaust duct, 23 outdoor exhaust duct, 31 outdoor air intake port, 32 exhaust port, 60 information terminal, 60a terminal communication unit, 600 buildings.

Claims

1. an air supply duct for supplying outdoor air into the room; an air supply fan provided in the air supply duct; an exhaust air duct for exhausting indoor air to the outside; an exhaust fan provided in the exhaust air duct; a filter provided in a first air passage, which is at least one of the intake air passage and the exhaust air passage, and which removes contaminants from air drawn into the first air passage; a control unit that acquires a first current of a first motor of a first fan provided in the first air passage when the motor is rotated at a first rotation speed and a second current of the motor when the motor of the first fan is rotated at a second rotation speed that is greater than the first rotation speed, calculates a ratio of a difference between the second current and the first current to a difference between the second rotation speed and the first rotation speed, and determines that the filter is clogged when this ratio is equal to or less than a reference value; A ventilation device comprising:

2. the control unit calculates the ratio as an initial value when use of the filter starts, and calculates the reference value based on the calculated initial value and a rate of change of the first current and the second current when the air volume in the first air passage decreases from the air volume when use of the filter starts to an air volume at which the filter is determined to be clogged.

10. The ventilation device of claim 1.

3. the control unit acquires the first current and the second current multiple times, and calculates the ratio using an average value of the acquired first current and an average value of the acquired second current.

10. The ventilation device of claim 1.

4. the control unit acquires the first current and the second current multiple times over two or more days, and calculates the ratio using an average value of the acquired first current and an average value of the acquired second current.

10. The ventilation device of claim 1.

5. The control unit calculates the ratio at a timing when a user in an environment where the pre-exchange ventilation device is installed is absent.

10. The ventilation device of claim 1.

6. The control unit acquires a change in the ratio over time from the start of use of the filter, extrapolates the acquired change in the ratio over time to determine a time when the ratio will reach the reference value, and predicts that clogging of the filter will occur at that time.

10. The ventilation device of claim 1.

7. The ventilation device according to claim 1 , wherein the control unit, when determining that the filter is clogged, notifies the user that the filter is clogged.

8. The ventilation device according to any one of claims 1 to 7; a heat exchanger that exchanges heat between the exhaust airflow flowing through the exhaust airflow duct and the intake airflow flowing through the intake airflow duct; A heat exchange type ventilation device equipped with:

9. an air supply duct for supplying outdoor air into the room; an air supply fan having a motor and provided in the air supply air passage; a filter provided in the air supply duct to remove contaminants from the air drawn into the air supply duct; a control unit that acquires a first current of the motor when the motor is rotated at a first rotation speed and a second current of the motor when the motor is rotated at a second rotation speed that is greater than the first rotation speed, calculates a ratio of the difference between the second current and the first current to the difference between the second rotation speed and the first rotation speed, and determines that the filter is clogged when this ratio is equal to or less than a reference value; A blower device comprising:

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