JP3287675B2 - Air quality monitoring device and air quality monitoring method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air quality monitoring device and an air quality monitoring method used for maintaining and improving a comfortable living environment.

[0002]

2. Description of the Related Art Changes in the air quality of a living environment, that is, changes in odor levels originating from the human body and various other sources,
Conventionally, various gas sensors, such as an odor sensor and a carbon dioxide sensor, have been exclusively used as air quality detecting means for detecting a change in carbon dioxide concentration or the like resulting from human respiration.

[0003]

The gas that changes the air quality of the living environment is generally a reducing gas. However, when the gas sensor is placed in such an environment for a long period of time, gas adsorption to the sensitive body or the housing progresses, and the reference state of the sensor, that is, the resistance value of the sensor in a clean environment or the reference output corresponding thereto changes, It often takes an extremely long time to desorb the gas and return to the reference state. Further, in some cases, a chemical reaction occurs between the gas and the sensor-sensitive material, causing an irreversible change, resulting in a decrease in gas sensitivity. In any case, accurate air quality monitoring cannot be performed.

In view of the above-mentioned problems of the conventional air quality monitoring device, the present invention quickly returns the characteristics of the gas sensor to the reference state, and always maintains the characteristics of the gas sensor at a predetermined reference state. It is an object of the present invention to provide an air quality monitoring device and a method therefor.

[0005]

SUMMARY OF THE INVENTION The present invention provides an air quality detecting means for detecting air quality, an air quality detecting control means for controlling the air quality detecting means, an ozone generating means for generating ozone, and an ozone generating means. And an ozone generation control unit that controls the ozone generation unit based on the detection result of the ozone detection unit.

[0006]

In the present invention, for example, the ozone generation means
A predetermined concentration and a predetermined amount of ozone are generated based on preset conditions, and the ozone is brought into contact with the gas sensor of the air quality detection means, and the reducing gas adsorbed on the gas sensor is oxidized and decomposed to clean the sensitive body surface of the gas sensor, The characteristics of the gas sensor are quickly returned to the reference state. Furthermore, by detecting the residual ozone concentration after the ozone generation is stopped by the ozone sensor of the ozone detection means, and by controlling the ozone generation means by the ozone generation control means so as to obtain an appropriate ozone generation amount based on the information, The characteristics of the gas sensor can always be maintained at a predetermined reference state.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of an air quality monitoring apparatus according to the present invention. In the figure, 1 is an air quality detection means, 2 is an air quality detection control means, 3 is an ozone generation means, 4 is an ozone generation control means, and 5 is an ozone detection means.

An air quality detecting means 1 detects an odorous gas or the like existing in a living environment and controls an air quality controlling means (not shown) such as an air purifier in accordance with the concentration level of the detected gas. It has a function of outputting a signal. In this embodiment, the air quality is detected by an outside air suction method, that is, a method of sucking outside air at a predetermined flow rate and introducing it to the air quality detection means. The introduced outside air is naturally discharged from the air quality detecting means.

The air quality detection control means 2 has a function of controlling the air quality detection means 1 in accordance with a preset air quality detection mode such as an intermittent mode or a continuous mode, and works in conjunction with the control of the air quality detection means 1. A function of controlling the operation of the generation control means 4.

The ozone detection means 5 has a function of detecting residual ozone and transmitting ozone concentration information to the ozone generation control means 4. In the present embodiment, a method of detecting the ozone remaining in the discharged air in a natural discharge process of the introduced outside air accompanying the suction of the outside air following the stop of the ozone generation is used.

The ozone generation control means 4 has a function of controlling the ozone generation means 3 in accordance with a predetermined air quality detection mode, a function of controlling the residual ozone concentration detected by the ozone detection means 5 and a preset threshold ozone concentration. To calculate the ozone concentration and the amount of ozone to be generated during the next air quality monitoring suspension period, and control the ozone generating means 3.

FIG. 2 is a flowchart showing the operation of the air quality monitoring device of the present embodiment. Here, the case of air quality detection in the intermittent mode will be described.

First, an operation signal is transmitted from the air quality detection control means 2 to the air quality detection means 1 and the intake of outside air is started, and at the same time, the air quality detection means 1 starts monitoring the air quality in the first cycle (step 11). ). Next, the air quality monitor is stopped at a preset timing (step 1).
2). Stop information of the air quality monitor is transmitted to the ozone generation control means 4.
Is transmitted by the ozone generator 3, a predetermined amount of ozone is generated (step 13). The generated ozone comes into contact with the gas sensor of the air quality detecting means 1 and oxidizes and decomposes the gas adsorbed on the gas sensor to clean it, and the characteristics of the gas sensor quickly return to the reference state. Next, the generation of ozone is stopped at a preset timing (step 14), and the intake of outside air is started to start the second cycle air quality monitoring (step 15). At the same time as entering the air quality monitoring period of the second cycle, the ozone sensor of the ozone detecting means 5 detects residual ozone (step 16), and the detected residual ozone concentration information is transmitted to the ozone generation control means 4. The ozone generation controller 4 compares the detected residual ozone concentration with a preset threshold concentration of residual ozone, and calculates the ozone concentration and the amount of ozone to be generated during the next air quality monitoring suspension period (step S3). 17).
Thereafter, the processes of (Step 12) to (Step 17) are repeated a predetermined number of times.

Next, experimental results will be described. An air quality monitor was performed on air containing 0.5 ppm of methyl mercaptan and 0.5 ppm of hydrogen sulfide. As a gas sensor used for the air quality detecting means 1, a gas sensor for detecting volatile sulfide having a SnO ₂ thick film sensitive body was used. Further, as the ozone sensor used for the ozone detecting means 5, an ozone sensor having a thin-film sensitive body containing In ₂ O ₃ and SnO ₂ as main components was used. As the ozone generation means 3, a creeping discharge type ozone generation electrode having an induction electrode and a discharge electrode formed on an alumina substrate was used. The air quality monitoring was performed in an intermittent mode for an air quality monitoring period of 10 minutes and an air quality monitoring stop period of 1 minute. The ozone concentration was 0.1 ppm, and the generation time was 10 seconds after the air quality monitor was stopped. The threshold concentration of residual ozone was 0.02 ppm. In the same monitor cycle, an air quality monitor without ozone generation was performed for comparison. One cycle of “air quality monitor-air quality monitor stop” is defined as one cycle, and this cycle is continuously performed for 1000 cycles. After 1000 cycles, the resistance value of the gas sensor in the air and the methyl mercaptan 0.5 pp
The sensitivity to the mixed gas of m and 0.5 ppm of hydrogen sulfide was determined and compared with the initial value. FIG. 3 shows the result. Circles indicate resistance values, and triangles indicate sensitivity. The solid line indicates the case where ozone is generated, and the broken line indicates the case where no ozone is generated. As can be seen from FIG. 3, when ozone was generated, both the resistance value and the sensitivity hardly changed compared to the initial value, but when ozone was not generated, the resistance value was changed. It is reduced to about 85% of the initial value, and the sensitivity is about 30%.
% Decreased. When ozone was generated, almost no gas adsorption was recognized in both the sensor sensitive body and the housing. However, when ozone was not generated, it was found that a considerable amount of gas adsorbed on the sensor-sensitive body and the housing remained adsorbed. Furthermore, even if a process of increasing the heating temperature of the sensor to promote desorption of gas is performed,
The gas adsorbed on the sensitive body was almost completely desorbed, but the gas adsorbed on the housing was hardly desorbed, so that the resistance value and the sensitivity could not be completely returned to the original reference state. If the heating temperature of the sensor is further increased in order to desorb the gas adsorbed on the housing, the physical properties of the sensitive body itself may change, which is not preferable.

As has been clarified in the above embodiment, by using the air quality monitoring device and the air quality monitoring method according to the present invention, the characteristics of the gas sensor used for the air quality detecting means can always be kept at the reference state. Therefore, the air quality can be accurately detected over a long period of time.

Unlike the above embodiment, a predetermined amount of ozone is generated at the same time when the air quality monitoring device is operated, and the characteristics of the gas sensor are set to a reference state before the air quality detection in the first cycle. It is also possible to program. In the case where the air quality monitoring device is not used for a long period of time, various gases may be adsorbed on the gas sensor and the characteristics may be changed. In such a case, this method is particularly effective. Also in the intermittent mode, the time of each process and the concentration of generated ozone can be changed according to the environmental conditions for monitoring the air quality.

Further, in the above embodiment, the case of detecting the air quality in the intermittent mode has been described. However, the same effect can be obtained in the continuous mode.

Further, in the above embodiment, a gas sensor for detecting volatile sulfide having a SnO ₂ thick film sensitive body was used as the air quality detecting means, but other materials or other forms of gas sensors may be used in the same manner. Can be used. In addition, a gas sensor that detects another gas according to a target odor can be used.

In the above embodiment, an ozone sensor having a thin-film sensitive body containing In ₂ O ₃ and SnO ₂ as main components is used as the ozone detecting means. However, other materials or other forms of the ozone sensor are used. May be used.

[0021]

As is apparent from the above description,
By using the air quality monitoring device and the air quality monitoring method according to the present invention, the characteristics of the gas sensor used for the air quality detection means can be constantly maintained in the reference state, so that the air quality can be accurately detected over a long period of time. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of an air quality monitoring device according to the present invention.

FIG. 2 is a flowchart showing an operation of the air quality monitoring device according to the embodiment of the present invention.

FIG. 3 is a graph showing a comparison of changes in characteristics of a gas sensor.

[Description of Signs] 1 Air quality detection means 2 Air quality detection control means 3 Ozone generation means 4 Ozone generation control means 5 Ozone detection means

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-306150 (JP, A) JP-A-3-71051 (JP, A) JP-A-5-126391 (JP, A) 37245 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F24F 1/00

Claims (7)

(57) [Claims] An air quality detecting means for detecting air quality, an air quality detecting control means for controlling the air quality detecting means, an ozone generating means for generating ozone, an ozone detecting means for detecting ozone, An air quality monitoring device comprising: an ozone generation control unit that controls the ozone generation unit based on a detection result of the ozone detection unit. 2. An air quality detecting means having a gas detecting function by a gas sensor and a function of outputting a signal for controlling an air quality controlling means for changing air quality. Air quality monitoring device. 3. The air quality detection control means has a function of controlling the air quality detection means according to a predetermined air quality detection mode.
The air quality monitoring device according to claim 1, further comprising a function of controlling the ozone generation control means. 4. An ozone generation controller compares the residual ozone concentration detected by the ozone detector with a preset residual ozone concentration, calculates the concentration of ozone to be generated and the amount of ozone to be generated, and calculates the ozone generation. The air quality monitoring device according to claim 1, further comprising a function of controlling the means. 5. An air quality monitoring apparatus according to claim 1, wherein said ozone detecting means has an ozone detecting function by an ozone sensor and a function of transmitting the detected ozone concentration to said ozone generation controlling means. 6. An air quality monitor is performed intermittently at predetermined time intervals by an air quality detection means, and a predetermined concentration and a predetermined amount of ozone are generated by an ozone generation means during an air quality monitor stop period. An air quality monitoring method, wherein the ozone generation control means controls the amount of ozone generated by the ozone generation means by calculating and controlling the amount of ozone generated by the ozone generation means. 7. An air quality monitor is continuously performed by an air quality detection means, and a predetermined concentration and a predetermined amount of ozone are generated by an ozone generation means at predetermined time intervals, and the ozone generation means is brought into contact with the air quality detection means to stop ozone generation. An air quality monitoring method, characterized in that the remaining ozone is detected by an ozone detector and the amount of ozone generated by the ozone generator is controlled by an ozone generation controller.