Air purifier and method for controlling the same
The air purifier is provided with a housing having an air intake port and an exhaust port, a filter unit including a photocatalytic filter and housed in a unit housing section within the housing, a light source that irradiates the photocatalytic filter with light, an air blowing fan that generates an air flow passing through the unit housing section, and a contamination sensor provided between the photocatalytic filter and the air blowing fan. In a case where a controller determines that organic substances excessively adheres to the photocatalytic filter on the basis of detection values of the contamination sensor, it drives the light source at the maximum light quantity and drives the air blowing fan at the minimum air speed to refresh the photocatalytic filter.
1 . An air purifier comprising:
an air blowing fan;
a photocatalytic filter that includes a photocatalyst;
a light source that irradiates the photocatalytic filter;
a first sensor that is disposed on a downstream side of the photocatalytic filter, in an air blowing direction of air blown by the air blowing fan, the first sensor being configured to detect organic substances contained in the air, and
a controller configured to:
refresh the photocatalytic filter by causing the light source to emit light at a maximum light quantity that is a largest one of light quantities emitted during operation of the air purifier, and by driving the air blowing fan at a minimum air speed that is a slowest one of air speeds generated during the operation of the air purifier,
perform first check processing to check an amount of organic substances adhering to the photocatalytic filter, the first check processing comprising:
causing the light source to emit light at a first light quantity and obtaining, from the first sensor, a first detection value indicative of a first amount of organic substances contained in the air,
causing the light source to emit light at a second light quantity, different from the first light quantity, and obtaining, from the first sensor, a second detection value indicative of a second amount of organic substances contained in the air, and
calculating a difference between the first detection value and the second detection value, and
determine, based on the calculated difference, whether further refreshing of the photocatalytic filter is necessary.
2 . The air purifier according to claim 1 , wherein:
the first detection value is an average value of detection results corresponding to a first predetermined number of times, obtained by driving the light source at the first light quantity, for a first predetermined period of time,
the second detection value is an average value of detection results corresponding to the first predetermined number of times, obtained by driving the light source at the second light quantity larger than the first light quantity, for the first predetermined period of time,
the maximum light quantity is larger than the second light quantity, and the light source is caused to emit light at the maximum light quantity in a case that the difference is smaller than a first determination value.
3 . The air purifier according to claim 2 , wherein
the difference is calculated for a second predetermined number of times that is two or more, and
the photocatalytic filter is refreshed in a case that a number of times that the difference is calculated as smaller than the first determination value is equal to a third predetermined number of times.
4 . The air purifier according to claim 1 , wherein
the first check processing is performed in a case that an initial detection value of the first sensor is equal to, or more than, a first predetermined value in a state in which the light source is turned off.
5 . The air purifier according to claim 1 , further comprising:
a second sensor that detects organic substances contained in air on an upstream side of the photocatalytic filter in the air blowing direction by the air blowing fan, wherein
the controller is further configured to perform, in a state in which the light source is caused to emit light at a predetermined light quantity based on a detection value of the second sensor, second check processing for checking contamination of the photocatalytic filter by determining a second difference between a third detection value obtained from the first sensor and a fourth detection value obtained from the second sensor.
6 . The air purifier according to claim 5 , wherein
the controller refreshes the photocatalytic filter by causing the light source to emit light at the maximum light quantity and driving the air blowing fan at the minimum air speed in a case that the second difference is smaller than a second determined value.
7 . The air purifier according to claim 5 , wherein
the second check processing is performed in a case that an initial detection value of the first sensor or an initial detection value of the second sensor, in a state in which the light source is turned off, is equal to, or more than, a first predetermined value.
8 . The air purifier according to claim 5 , wherein
the second difference is calculated for a first predetermined number of times that is two or more, and
the photocatalytic filter is refreshed in a case that a number of times that the second difference is calculated as smaller than the second determination value is equal to a second predetermined number of times.
9 . The air purifier according to claim 1 , wherein
the controller is configured to refresh the photocatalytic filter when an operation for sterilization and deodorization ends.
10 . The air purifier according to claim 9 , wherein
the controller is further configured to determine a time at which to refresh the photocatalytic filter based on a time taken for the operation for sterilization and deodorization.
11 . The air purifier according to claim 1 , wherein the photocatalytic filter is formed in a wave shape in which a hill section and a valley section that extend in a first direction are alternately arranged in a second direction orthogonal to the first direction, and an air flow is generated by the air blowing fan flow along the first direction.
12 . A method for controlling an air purifier, the air purifier comprising:
an air blowing fan;
a photocatalytic filter that includes a photocatalyst;
a light source that irradiates the photocatalytic filter; and
a first sensor that is disposed on a downstream side of the photocatalytic filter, in an air blowing direction of air blown by the air blowing fan, the first sensor being configured to detect organic substances contained in the air, the method comprising:
refreshing the photocatalytic filter by causing the light source to emit light at a maximum light quantity that is a largest one of light quantities emitted during operation of the air purifier, and by driving the air blowing fan at a minimum air speed that is a slowest one of air speeds generated during the operation of the air purifier;
performing first check processing to check an amount of organic substances adhering to the photocatalytic filter, the first check processing comprising:
causing the light source to emit light at a first light quantity and obtaining, from the first sensor, a first detection value indicative of a first amount of organic substances contained in the air,
causing the light source to emit light at a second light quantity different from the first light quantity and obtaining, from the first sensor, a second detection value indicative of a second amount of organic substances contained in the air, and
calculating a difference between the first detection value and the second detection value, and
determining, based on the calculated difference, whether further refreshing of the photocatalytic filter is necessary.