JPH0450494B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application The present invention relates to an automatic air blower that controls a blower section using an air pollution sensor made of a reduced or oxidized metal oxide semiconductor, and specifically relates to an air blower that controls an air blower using an air pollution sensor made of a reduced or oxidized metal oxide semiconductor. Used in machines, ventilation fans, deodorizers, air conditioners, etc.

(b) Prior art The air pollution sensor made of metal oxide semiconductors such as ZnO and SnO ₂ used in the present invention was developed in the
As shown in the characteristic diagram shown in Figure 1 of Publication No. 13680,
It has a characteristic that the sensor resistance decreases from infinity to several KΩ with the passage of time in the initial stage of energization, and then increases again and stabilizes from several +KΩ to several hundred +KΩ. The time it takes for an air pollution sensor to stabilize is not constant due to various problems in the manufacture of semiconductors such as metal oxides, and the stable sensor resistance also varies.

Therefore, the blower controlled using the air pollution sensor takes a long time (approximately 5 minutes) until the sensor stabilizes.
It was controlled independently of the addition of the sensor resistance of the air pollution sensor. This time (approximately 5 minutes) was set to be long enough to allow for variations in sensors.

As a result, if the blower uses an air pollution sensor that takes less time to stabilize than this set time, even if it stabilizes, it will not be possible to switch to automatic operation control using the sensor until the set time has elapsed; This could not be said to be sufficient for an automatic air blower that needs to shift to automatic control operation.

(c) Problems to be solved by the invention The present invention changes the time required to shift to automatic operation using an air pollution sensor, which was constant in conventional technology, and uses an air pollution sensor that stabilizes quickly. The automatic air blower is designed to shift to automatic operation in a short period of time.

(d) Means for solving the problems The configuration of the present invention will be explained based on FIGS. 1 and 2.

The automatic air blower includes an air pollution sensor 1 made of metal oxide semiconductors such as ZnO and SnO ₂ whose conductive properties change in response to reducing gases such as CO, and a sensor that detects peaks at wavelengths of 9 to 10 μm emitted from the human body. a human body sensor 2 that senses far-infrared rays and detects the presence of a person without contact; a blower section 3 whose operation is controlled by detection of at least one of the air pollution sensor 1 and the human body sensor 2; The air conditioner 4 is provided with an air conditioning section 4 through which the air flow A generated in the air conditioner passes.

The air conditioning section 4 is formed of a filter that collects smoke, dust, etc. contained in the air, and the filter includes a fiber filter made of a dielectric material to which an electric charge is applied and a deodorizing filter to which a deodorizing agent such as activated carbon is applied. Note that the air conditioning unit 4 may have any configuration as long as it can purify indoor air, and when the air conditioning device is a ventilation fan, the air conditioning unit 4 is an opening that communicates with the outdoors.

The sensor resistance of the air pollution sensor 1 is the gas detection part 2.
1, and after being processed there, is input to the automatic driving control unit 23. After being processed by the automatic operation control section 23, it is processed by the operation selection control section 24, and is output to the electric motor control section 25, so that the blowing section 3 is controlled. Here, each of these control units 23, 24, 2
5 is a control section as referred to in the claims.

(E) Effect In the present invention, as explained in the prior art, the sensor resistance R _S of the air pollution sensor 1 changes as shown by the solid line, dotted line, and dashed-dotted line in FIG. 5, and becomes stable.
Therefore, when the air pollution sensor 1 is stable, the sensor resistance differs only by _ΔR as shown in _{FIG .} The sensor resistance became stable.

Also, the time it takes for the sensor resistance R _S to stabilize is
Focusing on the characteristic that the sensor resistance is not constant but remains approximately constant for a predetermined period of time before stabilizing, we set a target value and conversely control it so that the sensor resistance becomes stable after a predetermined period of time has passed since it exceeded the target value. .

As a result, although there are some differences depending on the air pollution sensor, it is possible to determine the stable timing of almost all the air pollution sensors, and based on this, it is possible to shift to automatic operation using the gas detection unit 21 of the blower unit 3 at an early stage.

(f) Embodiment The present invention will be specifically explained using an air cleaner 5, which is a specific device of an automatic blower, as an example.

FIG. 3 is a perspective view, and FIG. 4 is a cross-sectional view. The air cleaner 5 has an air outlet 6 formed on one side of the upper surface, and a removable suction grille 7 formed at the front. A dispersion plate 8 is attached to the inner surface of the suction grill body 7 to divide the sucked air flow A to both sides. A breathable filter support plate 10 is disposed within the main body case 9 facing the dispersion plate 8. The filter support plate 10 is made of a wire mesh lath plate and is grounded as shown in FIG. The filter support plate 10 has an air conditioning section 4.
A fiber filter and a deodorizing filter are stacked and supported. The main body case 9 portion located on both sides of the dispersion plate 8 which is distributed from the suction grill body 7 to the air conditioning unit 4 is provided with a plate for ionizing the air flow A and charging the dust contained therein. A shaped counter electrode 11 and a needle shaped ionization electrode 12 are provided.
A blower 3 consisting of an electric motor 13 and blower blades 14 is mounted inside the main body case 9. The air flow A sent from the blower blade 14 is blown out. A plate-shaped counter electrode 15 and a needle-shaped ionization electrode 16 for ionizing the air flow A are disposed behind the air outlet 6.

The air cleaner 5 changes the amount of air blown by the air blower blades 14 by changing the rotational speed of the electric motor 13, thereby changing the amount of dust collected per hour by the air conditioner 4. In this structure, the electric motor 13
is changed to three stages: high speed, medium feed, and low speed.
The air cleaner 5 is controlled to switch between rapid operation, standard operation, and weak operation.

A control section 17 of the air cleaner 5 is formed on the other side of the upper surface of the main body case 9, and the control section 17 is formed of a box with electrical components inside, and is separable from the main body case 9. The main body case 9 and the control unit 17 may be electrically and mechanically connected by a lead wire,
The control signal from the control unit 17 may be transmitted wirelessly using a carrier such as infrared rays.

An air pollution sensor 1 made of a metal oxide semiconductor and a human body sensor 2 for detecting the presence of a person in a non-contact manner are mounted inside the upper surface of the main body case 9. The human body sensor 2 can be housed in the main body case 9 or protruded from the main body case 9 as needed, and can be directed in an appropriate direction in the protruding state.

The human body sensor 2 uses what is called a pyroelectric infrared sensor, which utilizes the pyroelectric effect of LiTaO ₃ single crystal. Pyroelectric infrared sensors operate with all wavelengths of infrared rays, such as light bulbs and the sun.9
Human body sensor 2 is used to detect far infrared rays from the human body surface and clothing that have a peak wavelength of ~10 μm.
A filter is attached to the light entrance part of the pyroelectric infrared sensor. In addition, since the human body sensor 2 is used to detect the presence of a person within a certain range rather than measuring local temperature, a light-receiving area and a non-light-receiving area are formed on the pyroelectric infrared sensor. The movement of the sensor causes a pyroelectric effect on the pyroelectric infrared sensor to detect the presence of a person. Therefore, a lens body is attached to the light entrance part of the pyroelectric infrared sensor to form a light receiving area and a non-light receiving area. The lens body is made of a Fresnel lens made of polyethylene that transmits human body infrared wavelengths of 7 to 14 μm. In this structure, the detection range of the human body sensor 2 is set to 80 degrees in the horizontal direction and 20 to 25 degrees in the vertical direction, and the detection distance is approximately 5 m.

The air purifier 5 can be used in various configurations such as floor-mounted, shelf-mounted, wall-mounted, and ceiling-mounted. When mounted on a wall, in order to obtain indoor air circulation effects, the air purifier 5 is placed on the floor as shown in Fig. 3. It is used in reverse.

The electric circuit of the air purifier 5 is as shown in FIG. An automatic operation control section 23 receives detection signals from the detection section 21 and the human body detection section 22 and outputs control signals for performing automatic operation, which will be described later. and a motor control section 25 that controls the electric motor 13 based on command signals from the operation selection control section 24.
and the counter electrode 11, in conjunction with the motor control unit 25.
15, a DC high voltage section 26 that applies a high voltage between the ionization electrodes 12 and 16, an operation section 27 that issues operation instructions to the operation selection control section 24, a security switch 28, and an operation detection operation for the air purifier 5. It includes an operation display section 29 that shows the state, a gas detection display section 30, a human body detection display section 31, and a notification section 32. The operating section 27 is formed by a switch and a variable resistor,
Stop switch and automatic operation, weak operation, standard operation,
It is equipped with an operation changeover switch that sequentially switches between rapid operations, a timer selection switch that selects the time for timer operation, and a sensitivity adjustment resistor that adjusts the sensitivity of the air pollution sensor 1. The security switch 28 is for providing a function of detecting a person using the human body sensor 2 in parallel with the operation as the air purifier 5. When the security switch 28 is turned on, when the human body sensor 2 detects a person, Notification section 32
The buzzer that makes up the sound sounds. The operation display section 29
It is formed of a light emitting body such as an LED, and displays automatic, weak, standard, and rapid operation, timer operation time, and whether the security switch 28 is on or off. The gas sensing display unit 30 is formed of a light emitting body that changes color between red and green, and if the air is dirty as detected by the air pollution sensor 1, it lights up in red, and if it is full, it lights up in green. The human body sensing display section 31 is formed of a light emitting body such as an LED that lights up when the human body sensor 2 detects the detection. The notification section 32 is formed of a sounding body such as a piezoelectric buzzer, and emits a confirmation sound when the operation section 27 is operated, and also outputs a confirmation sound when the operation section 27 is operated.
8. Produces a warning sound when charging.

Next, the operation of the air cleaner 5 will be explained based on FIG. 1.

First, when the operation selector switch on the operation unit 27 is operated, it is determined whether it is "manual or automatic", and if manual, so-called weak operation, standard operation, or rapid operation is selected, the selected operation state is selected. Operated continuously. When automatic operation, so-called operation based on air pollution sensor 1 and human body sensor 2, is selected, weak operation is started. This weak operation is a temporary operation until the air pollution sensor 1 can perform normal detection.

Temporary operation will be explained based on Fig. 1. It is determined whether the sensor resistance R _S of the air pollution sensor 1 exceeds the target value. If it exceeds the target value, then a timer for T ₁ minute is activated, and the timer for T ₁ minute is activated. If the time has elapsed, it is determined that the detection by the air pollution sensor 1 is being performed normally. However, if the air pollution sensor 1 does not reach the target value, or even if it reaches the target value but a considerable amount of time has elapsed, the transition to steady operation will not occur smoothly. This phenomenon occurs due to variations in the characteristics of the air contamination sensor 1 and when automatic operation is started in a room where the air is contaminated from the beginning. Therefore, in parallel with the operation described above, after automatic operation is selected, a timer is activated for the so-called elapsed time t ₁ minute after the power is turned on, and when the state is reached, whichever comes first, the air pollution sensor 1 is activated.
It is determined that normal detection has become possible.
In this structure, T ₁ minute is set to 2 minutes, and t ₁ minute is set to 5 minutes.

Furthermore, the operation of the above-mentioned provisional operation will be explained together with the change in the sensor resistance R _S of the air pollution sensor 1. Figures 5 and 6 show changes in sensor resistance R _S at the initial stage of operation. In FIG. 5 and FIG. 6, the air pollution sensor 1 has changed due to changes in its manufacturing conditions.
As shown by the solid line, dotted line, and dashed-dotted line, even when the sensor resistance changes and at the same time reaches a steady state, the sensor resistance value differs by approximately ΔR. The air pollution sensor 1 has a high sensor resistance at first, then rapidly decreases, then increases again and becomes stable, and when it increases again, the sensor resistance value that normally passes is set as a target value, and the passing point is set as P. , Q, R, and W. When passing P, Q, R, and W, the T _1- minute (2-minute) timer is activated, and after the time has elapsed, it is determined that it has stabilized, and the sensor resistances R _SP , R _SQ , and R _SW are input as detected by air pollution sensor 1. be done.
However, the one-dot chain line in Figure 5 indicates that t _{1 minute (5 minutes) will pass before T 1 minute} (2 minutes) after passing point R, and that t will be stable after t ₁ minute (5 minutes) has passed. , and input the sensor resistance R _SR as detection. 6th
The dotted line in the figure indicates that the target value has not been reached, so t ₁ minute (5 minutes)
After the elapsed time, it is determined that it has stabilized and the sensor resistance R _SX is input as a detection.

In addition, the 5 minutes set as t ₁ minute was set because it is the time when air pollution sensor 1 is normally stabilized, but there is no particular need to set t ₁ minute to 5 minutes, and it may be 4 minutes or 6 minutes. . Also, T ₁ minute is set to 2 minutes, so it may be 1 minute or 3 minutes. However, it is best to keep the interim operation short after the air purifier 5 starts operating, and a maximum of 5 minutes is optimal, and even if there is some variation in performance of the air pollution sensor 1, t ₁
Provisional operation will not be carried out for more than a minute. Since the sensor resistance is 80 to 130KΩ when stabilized, the target value that is the standard for T ₁ minute is about 2 minutes before that.
The resistance was set to 20KΩ, and the time _T1 was 2 minutes. The optimum values of 20KΩ and 2 minutes were determined through experiments, but 30KΩ and 1 minute and 30 seconds are also acceptable, and can be determined as appropriate.

When the provisional operation ends, first a comparison is made between the reference value and the sensor resistance R _S. In the comparison judgment that is first made after the provisional operation, reference values for that purpose are stored in advance as temporary reference values shown in FIGS. 5, 6, and are compared with the temporary reference values. The provisional standard value is a value at which the sensor resistance when the air pollution sensor 1 is stabilized in an atmosphere with clean air will not be less than this even if there is a difference in the characteristics of the air pollution sensor 1.
It is set to 70KΩ. Therefore, in Fig. 5, since the sensor resistances R _SP , R _SQ , and R _SR after provisional operation are all larger than the provisional reference values, it is determined that the air in the room is clean, and the sensor resistances R _S , R _SP , R _SQ , R _SR
is stored as a reference value, and the process moves to the step shown in FIG.

In Fig. 6, the sensor resistance R _SW after provisional operation,
Since R _SX is smaller than the provisional standard value, it is determined that the air in the room is contaminated, and the system shifts to regular air cleaning operation. As shown in Figs. 5 and 6, the air pollution sensor 1 indicates that reducing gases such as CO contained in the air increase (increases in proportion to smoking, and in this state it increases in proportion to the increase in smoke). In this case, the sensor resistance is reduced.

When automatic operation is selected in a state where the indoor air is clean, the human body sensor 2 detects the presence or absence of a person and the air pollution sensor 1 detects the magnitude of the sensor resistance R _S relative to the reference value, starting at the point in Figure 1. . When the human body sensor 2 detects a person, a human body timer for counting T minutes is started, and it is determined whether the security switch 28 is turned on or not. When the security switch 28 is turned on, a notification section 32 sounds to notify the presence of a person in the room. The notification by the notification section 32 at this time is made different from the confirmation sound when the operation section 27 is operated. If there is a detection by the human body sensor 2, the air purifier 5 is operated in a weak manner, and the weak operation is continued until the human body timer finishes measuring T minutes (20 minutes), and after T minutes have passed, the air purifier 5 is started to stop operation. Return to

Even while the human body timer is measuring time, the air pollution sensor 1 detects the magnitude of the sensor resistance R _S with respect to the reference value, and the human body timer detects the person again. If there is a detection by the air pollution sensor 1 at the initial stage or during timing by the human body timer, the operation shifts to a steady air cleaning operation.

Human body sensor 2 during time measurement by human body timer
If a person is detected, the human body timer is reset and starts counting. Therefore, if a person is constantly moving indoors without being detected by the air pollution sensor 1, the person's movement will stop and the weak operation will continue unless the person leaves the room. Wet operation based on the human body sensor 2 is set because dust, etc. is suspended in the air due to the movement of people indoors, and low operation is optimal for collecting dust in terms of dust collection ability and operation noise. has been done. Furthermore, if there are people present, it is expected that people will smoke, and since the initial stage of smoking is handled smoothly and there is a flow in the air, the transition to regular air purification operation by the air pollution sensor 1 is also performed smoothly. .

Also, although it is not clear in the flowchart of FIG. 1 that the time measurement of the human body timer based on the detection of the human body sensor 2 and the time measurement performed by resetting the time based on the re-detection are performed, the operation control of the air purifier 5 is Even if the operation shifts to steady operation using the air pollution sensor 1, the human body sensor 2
The human body timer always measures time by detecting a person by the human body sensor 2, and returns to the point when the steady operation by the air pollution sensor 1 ends, and stops after the human body timer finishes measuring T minutes. When returning to , the timing of T minutes will be a weak operation with only the remaining T minutes.

Therefore, automatic operation of the air purifier 5 based on the air pollution sensor 1 and the human body sensor 2 is started by detection of the sensor output of either the air pollution sensor 1 or the human body sensor 2, and the detection of both sensor outputs is started. It is stopped when it disappears.

Steady operation by the air pollution sensor 1 will be explained. The transition to steady operation based on the detection of the air pollution sensor 1 is performed in a state where the sensor resistance R _S has become smaller than the reference value, but the operation of the air purifier 5 includes rapid operation, standard operation, and weak operation, and each operation The transition to is performed at the ratio of the sensor resistance R _S to the reference value. In this structure, if 0.6<R _S /Reference value<0.7, it will be in weak operation, if 0.5<R _S /Reference value<0.6, it will be in standard operation, and if R _S /Reference value<0.5, it will be in rapid operation.
These 0.5, 0.6, and 0.7 are set values, and R _S /Reference value>
At 0.7, there is no need to purify the air, so they wait for the air to become even more polluted.

When the detection by the air pollution sensor 1 becomes smaller than the set value of 0.7, which is sufficient to shift to operation, this structure does not immediately shift to the selected operation, but operates for 10 minutes in standard operation. This 10 minute standard operation is called stirring operation. In other words, if particularly dirty air is temporarily detected in some areas by the air pollution sensor 1, there is no need to shift to steady operation, so first stir the indoor air and then compare it again with the set value. It is something to do. After stirring operation, R _S / If the reference value is greater than 0.7, it will shift to, and if it is less than 0.7, it will change to the set value.
Shift to operation against the R _S /reference value. After transitioning to each operation, the ratio of the sensor resistance R _SS detected a certain period of time (3 minutes) ago to the latest sensor resistance R _S
Based on the comparison between R _S /R _SS and the set value, each operation is switched as appropriate, and the air conditioner 4 cleans the indoor air. When it is determined that air purification has finished, the OFF timer is started and measures T ₂ minutes (set as appropriate between 20 and 40 minutes), and then T ₂
If it is determined that the air is contaminated again while counting the minutes.
Air purification is started again in each of the above-mentioned operations in which the OFF timer is reset. When the OFF timer finishes counting _T2 minutes, the reference value is transferred to the sensor resistance R _S when the OFF timer finishes counting.

The change in sensor resistance during the above-mentioned steady operation is as shown in FIG. Referring to FIG. 7, as detected by the air pollution sensor 1, when stirring operation is performed for 10 minutes as standard, the sensor resistance becomes large and the operation is stopped. After that, the sensor resistance became small again, so the agitation operation was performed for 10 minutes, and when it was detected again, it corresponded to weak operation compared to the set value, so it became weak operation, and then switched to standard operation due to the progress of air pollution. When operating in standard operation, the difference between R _S and R _SS becomes small and the OFF timer starts counting, but the air becomes dirty again and the degree of contamination corresponds to rapid operation, so rapid operation is performed, and eventually R _S and R _SS
The OFF timer starts counting and stops as the difference between the two becomes smaller. Note that even when the air purifier 5 is operated, the sensor resistance R _S does not become as large as it was at the beginning of operation, as shown in Fig. 7, because smoke is collected by the air conditioner 4, but the reducing nature of CO, etc. This is because the gas is not collected. Therefore, the sensor resistance R _S when the operation of the air pollution sensor 1 is completed is updated to the reference value. Note that the reference value is updated using the sensor resistance.
This is also done when R _S increases, and the sensor resistance R _S increases due to the natural attenuation of reducing gas and ventilation by opening and closing windows and doors, so that the reference value is always set at the indoor reducing gas concentration. I have to.

(G) Effects of the Invention According to the automatic air blowing device of the present invention, automatic operation by the gas detection unit is started as soon as the characteristics of the sensor become stable, without having to wait for a certain period of time after the start of energization to the air pollution sensor as in the conventional case. This allows the air pollution sensor to fully utilize its functions at an early stage.

[Brief explanation of the drawing]

The drawings show the present invention: Fig. 1 is a flowchart, Fig. 2 is a block circuit diagram, Fig. 3 is a perspective view, Fig. 4 is a sectional view, and Figs. 5, 6, and 7. FIG. 2 is a characteristic diagram showing sensor resistance and time changes in different situations. 1... Air pollution sensor, 3... Air blower, 4...
Air conditioning section, 21... Gas detection section, 23... Automatic operation control section, 24... Operation selection control section, 25...
Electric motor control section.

Claims (1)

[Claims] 1. An air pollution sensor made of a metal oxide semiconductor whose sensor resistance changes upon contact with a reducing gas, etc.; a gas detection section that processes the sensor resistance of the air pollution sensor; In the process of increasing, the output of the gas detection section is changed to the output of the gas detection section at the earlier of a predetermined time after the value reaches the target value, or after a predetermined time longer than the predetermined time from the start of the energization. An automatic blower device comprising: a control section that controls the blower section;